JP2003215589A - Forward illumination device and reflecting type liquid crystal display device equipped with it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve utilization efficiency of light source light in a forward illumination device arranged at a front face of illuminated material of reflecting type LCD or the like. <P>SOLUTION: Flat parts 21 and slanted parts 22 are alternately arranged on the interface 23 of a light guide body 24a in a front light 20a. The sum of a width in each flat part 21 and a width in each slanted part 22 is gradually decreased as the distance to a light source 26 is increased. That is, the number of the slanted parts 22 per unit area is increased as the distance to the light source 26 is increased. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used by being arranged between an object to be illuminated and an observer, irradiating the object to be illuminated with light, and allowing an observer to visually recognize reflected light from the object to be illuminated. The present invention relates to a front illumination device configured to transmit the reflected light as described above, and a reflective liquid crystal display device including the front illumination device as an auxiliary light source.

[0002]

2. Description of the Related Art A liquid crystal display device is a CRT (Cathode Ray T
ube), PDP (Plasma Display Panel), or EL (E
Unlike other displays such as lectro Luminescence), the liquid crystal itself does not emit light, but characters and images are displayed by adjusting the amount of light transmitted from a specific light source.

A conventional liquid crystal display device (hereinafter, LCD: Liqu
The “id Crystal Display” can be roughly classified into a transmissive LCD and a reflective LCD. Transmission type LC
In D, a surface emitting light source such as a fluorescent tube or EL is disposed as a light source (backlight) on the back surface of the liquid crystal cell.

On the other hand, the reflective LCD has the advantages that it does not require a backlight and consumes less power because it uses ambient light for display. Further, in a very bright place such as exposed to direct sunlight, the display of the emissive display and the transmissive LCD becomes almost invisible, while the display of the reflective LCD becomes clearer. Therefore, the reflection type L
The CD is applied to mobile information terminals and mobile computers, which have been in increasing demand in recent years.

However, the reflective LCD has the following problems. That is, since the reflective LCD uses ambient light, the display brightness is highly dependent on the surrounding environment, and the display may not be recognized at all in the darkness such as at night. In particular, in the reflective LCD using a color filter for colorization or the reflective LCD using a polarizing plate, the above-mentioned problem is large, and auxiliary lighting is necessary in case sufficient ambient light cannot be obtained. Become.

However, the reflective LCD has a reflector installed on the back surface of the liquid crystal cell, and cannot use a backlight like the transmissive LCD. A device called a semi-transmissive LCD using a half mirror as a reflector has also been proposed, but its display characteristics are halfway between a transmissive type and a reflective type and are considered to be difficult to put into practical use.

Therefore, a front light system for arranging it in front of a liquid crystal cell has been conventionally proposed as auxiliary illumination for a reflective LCD when the surroundings are dark. This front light system generally comprises a light guide and a light source arranged on a side surface of the light guide. The light source light incident from the side surface of the light guide body travels inside the light guide body, is reflected by the shape formed on the surface of the light guide body, and is emitted to the liquid crystal cell side. The emitted light is dimmed according to the display information while passing through the liquid crystal cell, and is reflected by the reflecting plate arranged on the back side of the liquid crystal cell, and again passes through the light guide body to the viewer side. Is emitted. This allows the observer to recognize the display even when the amount of ambient light is insufficient.

Such a front light is disclosed, for example, in Japanese Patent Laid-Open No. 5-158034, SID DIGEST P.375 (1).
995) and the like.

[0009]

[Problems to be Solved by the Invention] Here, SID DIGEST
The operation principle of the front light system disclosed in P.375 (1995) will be briefly described with reference to FIG. In the above front light system, the flat portion 10
One side surface of the light guide body 104 having the interface 101 formed of 1a and the inclined portion 101b is defined as an incident surface 105 on which light from the light source 106 is incident. That is, the light source 10
6 is arranged at a position facing the incident surface 105 of the light guide 104.

Of the light that has entered the light guide 104 from the light source 106 through the incident surface 105, some of the light goes straight, and some of the light enters the interface 101.1 between the light guide 104 and its surrounding medium.
It is incident on 08. At this time, assuming that the surrounding medium of the light guide body 104 is air and the refractive index of the light guide body 104 is about 1.5, the interface 1 is calculated from Snell's law (Equation 1).
It can be seen that the light whose incident angle with respect to 01 · 108 is about 41.8 ° or more is totally reflected at the interfaces 101 · 108.

N ₁ · sin θ ₁ = n ₂ · sin θ ₂ θ _c = arcsin (n ₂ / n ₁ ) (Equation 1) where n ₁ is the first medium (here, the light guide 104) Refractive index, n ₂ is the refractive index of the second medium (here, air),
θ ₁ is the incident angle from the light guide 104 to the interface 101, θ ₂ is the exit angle from the interface 101 to the second medium, θ _c is the critical angle,
Is.

In the light incident on the interfaces 101 and 108,
The light totally reflected by the inclined portion 101b, which is a reflection surface, and the interface 1
After being totally reflected at 08, the light reflected by the inclined portion 101 b of the interface 101 enters the liquid crystal cell 110. Liquid crystal cell 11
The light that has entered 0 is modulated by a liquid crystal layer (not shown), is then reflected by a reflection plate 111 provided on the back surface of the liquid crystal cell 110, and is incident on the light guide 104 again to enter the flat portion 10.
The light passes through 1a and is emitted to the observer 109 side.

The light that has passed from the light source 106 through the incident surface 105 and is incident on the flat portion 101a instead of the inclined portion 101b is between the interface 101 and the interface 108.
It propagates while repeating total reflection until it reaches b. The area of the inclined portion 101b viewed from the observer 109 side is
The area is sufficiently smaller than the area of the flat portion 101a.

The above conventional front light system has the following problems. (1) As shown in FIG. 52, the light that cannot reach the inclined portion 101b even if the total reflection is repeated, or the light that is incident substantially perpendicularly to the incident surface 105 is the surface 10 facing the incident surface 105.
7 becomes the light 114 emitted to the outside of the light guide 104 and cannot be used for display. That is, the utilization efficiency of light is poor. (2) The shape of the interface 101 composed of the inclined portion 101b and the flat portion 101a is similar to the shape in which the apex of the prism sheet is just flattened, and as shown in FIG. It is likely to be reflected to the side, leading to deterioration in display quality.

These problems are common to most of the conventional front light systems, and improvement of utilization efficiency of light from the light source is desired.

The present invention has been made in view of the above problems, and an object of the present invention is to improve the utilization efficiency of light from a light source and to provide a uniform and brighter illumination to an object to be illuminated. An object is to provide an illuminating device and a reflective liquid crystal display device using the front illuminating device.

[0017]

In order to solve the above-mentioned problems, a front lighting device according to the present invention has a light source and a light guide arranged in front of an object to be illuminated. The light body includes an incident surface on which light from the light source is incident, a first emission surface on which light is emitted toward the object to be illuminated, and the first
And a second emission surface that emits the reflected light from the object to be illuminated, and that mainly emits light from the light source to the second emission surface. An inclined portion that reflects toward the surface and a flat portion that mainly transmits the reflected light from the object to be illuminated are alternately formed, and as the distance from the light source increases, the width of the flat portion and the width of the inclined portion are increased. The feature is that the sum of is gradually decreased.

In order to solve the above-mentioned problems, another front illumination device according to the present invention has a light source and a light guide arranged in front of the object to be illuminated. Is an incident surface on which the light from the light source is incident, a first emission surface that emits light toward the object to be illuminated, and a reflected light from the object to be illuminated that faces the first emission surface. A second emitting surface for emitting light, and an inclined portion that mainly reflects light from the light source toward the first emitting surface, and the illuminated object is mainly the second emitting surface. Flat portions that transmit reflected light from are alternately formed, and the number of the inclined portions per unit area increases as the distance from the light source increases.

In the former configuration, the sum of the pitch of the flat portion and the pitch of the inclined portion becomes smaller as the distance from the light source increases. In the latter configuration, the number of the inclined portions per unit area becomes greater from the light source. Increase with the increase. As a result, the brightness on the surface of the object to be illuminated improves as the position moves away from the light source. Usually, since the brightness tends to decrease as the position is farther from the light source, in any of the above configurations, the decrease in the brightness of the illuminated object due to the distance from the light source is offset, and the light from the light source is emitted at a high angle. It is possible to efficiently guide the entire object to be illuminated. As a result, the luminance distribution on the surface of the illuminated object can be averaged.

The front lighting device according to the present invention is characterized in that, in addition to the above configuration, the incident surface is present on a side surface of the light guide.

According to the above arrangement, since light is incident from the side surface of the light guide, there is an advantage that the light source cannot be directly seen by the observer. As a result, the front illumination device is realized in which the direct light from the light source does not affect the image of the illuminated object and a clear image of the illuminated object is obtained.

The front illumination device according to the present invention is characterized in that, in addition to the above-mentioned structure, it further comprises a condensing means for making the light from the light source incident only on the incident surface.

According to the above arrangement, the loss of light from the light source can be further reduced, so that the utilization efficiency of the light from the light source is further improved and a front illumination device as a brighter surface light source is realized.

The reflection type liquid crystal display device according to the present invention is characterized in that, in order to solve the above-mentioned problems, the front illumination device having the above-mentioned structure is arranged on the entire surface.

Thus, when there is a sufficient amount of ambient light such as outdoors in the daytime, the front illumination device is used in the off state, while when the sufficient amount of ambient light cannot be obtained, the front illumination device is used. Can be lit and used. As a result, it is possible to provide a reflective liquid crystal display device that can always realize bright and high-quality display regardless of the surrounding environment.

In order to solve the above problems, another reflection type liquid crystal display device according to the present invention has a light source and a light guide arranged in front of an object to be illuminated. The light body includes an incident surface on which the light from the light source is incident, a first emission surface that emits light toward the object to be illuminated, and a first emission surface that faces the object and is reflected from the object to be illuminated. A second emitting surface that emits light is provided, and an inclined portion that mainly reflects the light from the light source toward the first emitting surface is provided on the second emitting surface, and mainly the illuminated surface. A front illumination device in which flat portions that transmit reflected light from an object are alternately formed; and a reflective liquid crystal element having a reflection plate on the first emission surface of the front illumination device. reflective liquid crystal device comprises a scanning line, the pitch P ₁ of the scanning lines, the front lighting apparatus Serial relationship with the sum w ₃ between the pitch of the pitch and the inclined portion of the flat portion of the second exit surface, w ₃ ≠ P
It is characterized by being ₁ .

According to the above arrangement, the pitch of the inclined portion of the front lighting device and the pitch of the black matrix formed around the pixels of the reflective liquid crystal element deviate from each other. As a result, it is possible to suppress the generation of moire fringes due to the interference between the black matrix and the inclined portion, and thus it is possible to improve the display quality of the obtained reflective liquid crystal display device.

In the reflection type liquid crystal display device according to the present invention, in addition to the above structure, the relationship between P ₁ and w ₃ is w ₃ > 2.
The feature is that P ₁ or w ₃ <1 / 2P ₁ .

According to the above structure, since it is possible to further suppress the generation of moire fringes due to the interference between the black matrix and the inclined portion, it is possible to further improve the display quality of the obtained reflection type liquid crystal display device. it can.

[0030]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [Embodiment 1] An embodiment of the present invention will be described with reference to FIGS.
It is as follows.

The reflective LCD according to this embodiment is shown in FIG.
As shown in, a reflective liquid crystal cell 10 (reflective liquid crystal element)
The front light 20 (front illumination device) is provided on the front surface of the.

The front light 20 mainly comprises a light source 26.
And a light guide 24. Light source 26
Is a linear light source such as a fluorescent tube, and is arranged along the side surface (incident surface 25) of the light guide 24. The light guide 24 is
The interface 28 (first emission surface) on the liquid crystal cell 10 side is formed flat. On the other hand, in the light guide 24, the interface 28
The interface 23 (second emission surface) that faces the flat portion 21 and the flat portion 21 that are formed parallel or substantially parallel to the interface 28.
The inclined portions 22 that are inclined at a constant angle in the same direction with respect to 1 are formed alternately. That is, as is apparent from FIG. 1, the light guide body 24 is formed in a stepwise shape that lowers as it goes away from the light source 26 in a cross section whose normal line is the longitudinal direction of the light source 26.

The inclined portion 22 mainly acts as a surface for reflecting the light from the light source 26 toward the interface 28. On the other hand, the flat portion 22 mainly acts as a surface for transmitting the reflected light to the observer side when the illumination light from the front light 20 returns from the liquid crystal cell 10 as the reflected light.

Now, the shape of the light guide 24 will be described in more detail with reference to FIGS. 2 (a) to 2 (c). 2A is a plan view of the light guide 24 as seen from above in the normal direction of the flat portion 21, and FIG. 2B is a side view of the light guide 24 as seen in the direction of normal to the incident surface 25. 2C is a cross-sectional view of the light guide 24 taken along a plane perpendicular to both the incident surface 25 and the interface 28.

The light guide 24 is made of, for example, PMMA (polymethy).
It can be formed by injection molding using lmetacrylate) or the like. The light guide 24 according to this embodiment has a width W = 1.
10.0 mm, length L = 80.0 mm, incident surface 25 portion thickness h ₁ = 2.0 mm, flat portion 21 width w ₁ = 1.9
mm. Further, the step h ₂ of the inclined portion 22 is 50 μm,
By setting the inclination angle α of the inclined portion 22 with respect to the flat portion 21 to be 30 °, the width w ₂ of the inclined portion 22 is about 87 μm.

The front light 20 has the following advantages because the light guide 24 is formed in a stepwise shape. First, as shown in FIG. 2B, when viewed from the direction normal to the incident surface 25, if the flat portion 21 is formed completely parallel to the interface 28, the flat portion 21 is visually recognized. Instead, only the inclined portion 22 is visually recognized. That is, the sum of the projections of the inclined portion 22 on the incident surface 25 is equal to the incident surface 25.

In such a case, of the light source light incident from the incident surface 25, all the components perpendicular to the incident surface 25 are directly incident on the inclined portion 22 and reflected toward the interface 28. As a result, the problem that a large amount of light is emitted to the outside of the light guide from the surface facing the incident surface, unlike the above-described conventional front light system, does not occur. That is, since the front light 20 is provided with the step-shaped light guide 24, the light utilization efficiency is significantly improved as compared with the conventional configuration.

Next, the structure of the liquid crystal cell 10 and its manufacturing method will be described. As shown in FIG. 1, the liquid crystal cell 10 basically has a structure in which a pair of electrode substrates 11 a and 11 b sandwich a liquid crystal layer 12. The electrode substrate 11a includes a transparent electrode 15a on a glass substrate 14a having optical transparency.
A (scanning line) is provided, and a liquid crystal alignment film 16a is formed so as to cover the transparent electrode 15a.

The glass substrate 14a is realized by, for example, a Corning glass substrate (trade name: 7059). The transparent electrode 15a is made of, for example, ITO (Indium Tin Oxid).
Use e) as a material. The liquid crystal alignment film 16a is, for example, an alignment film material manufactured by Japan Synthetic Rubber Co., Ltd. (trade name: AL-4552).
Is applied by a spin coater on the glass substrate 14a on which the transparent electrode 15a is formed, and a rubbing process is performed as an alignment process.

Like the electrode substrate 11a, the electrode substrate 11b is also formed by sequentially laminating the glass substrate 14b, the transparent electrode 15b, and the liquid crystal alignment film 16b.
An insulating film or the like may be formed on the electrode substrates 11a and 11b, if necessary.

The electrode substrates 11a and 11b are the liquid crystal alignment film 1
6a and 16b are arranged so as to face each other, and the rubbing processing directions are parallel and opposite (so-called anti-parallel), and they are bonded using an adhesive. At this time,
Glass electrode spacers (not shown) having a particle diameter of 4.5 μm are previously dispersed between the electrode substrates 11a and 11b, so that voids are formed at uniform intervals.

The liquid crystal layer 12 is formed by introducing liquid crystal into the voids by vacuum degassing. As the material of the liquid crystal layer 12, for example, a liquid crystal material manufactured by Merck Ltd. (trade name: ZLI-3926) can be used. The Δn of this liquid crystal material is 0.2030. However, the liquid crystal material is not limited to this, and various liquid crystals can be used.

Further, on the outer surface of the glass substrate 14b, a hairline-processed aluminum plate is used as the reflection plate 17.
For example, a polarizing plate 18 is attached to the outer surface of the glass substrate 14a while the polarizing axis is set so as to form 45 ° with the alignment direction of the liquid crystal of the liquid crystal layer 12 while being adhered by an epoxy adhesive.

Through the above steps, the reflective liquid crystal cell 10
Is manufactured. By combining the liquid crystal cell 10 with the front light 20 as described below, a reflective LCD with a front illumination device is manufactured. First, the liquid crystal cell 1
The light guide 24 is laminated on the zero polarizing plate 18. It should be noted that spacers (not shown) having a particle size of 50 μm are previously dispersed between the polarizing plate 18 of the liquid crystal cell 10 and the light guide 24, so that a uniform thickness approximately equal to the particle size of the spacer is obtained. A void 29 is formed. That is, the interface 28 of the light guide 24 optically corresponds to the interface between the PMMA and the air layer. Since the gap 29 has a thickness of about 100 times the wavelength of light, the occurrence of interference or the like due to the gap 29 is suppressed.

Next, a fluorescent tube is installed as a light source 26 so as to face the incident surface 25 of the light guide 24, and the light source 26 and the incident surface 25 are surrounded by a reflecting mirror 27 (light collecting means). Reflector 2
7 focuses the light from the light source 26 only on the incident surface 25. As the reflecting mirror 27, for example, aluminum tape or the like can be used. Through the above steps, the reflective LCD including the front light 20 as auxiliary illumination is completed.

This reflective LCD is used in a lighting mode in which the front light 20 is turned on when ambient light is insufficient, and when sufficient ambient light is obtained, the front light 2 is used.
It can be used in reflection mode with 0 turned off.

Here, the operation principle of the front light 20 will be described with reference to FIGS. 3 (a) to 3 (c). As described above, in the light guide 24, the sum of the projections of the inclined portion 22 on the incident surface 25 is equal to that of the incident surface 25. Therefore, of the incident light from the light source 26, the component perpendicular to the incident surface 25 is reflected by the inclined portion 22 as shown in FIG. 3 (a), and is reflected from the interface 28 in FIG. 3 (a). It is output toward the liquid crystal cell 10 (not shown).

As shown in FIG. 3B, the light source 26
Of the incident light from, the component that first enters the interface 23 is
There are two types according to the behavior in the light guide 24. One is the inclined portion 22 like the light 31a shown in FIG.
Is directly incident on and reflected by the output light 31 to the liquid crystal cell 10.
It is the light which becomes b. The second is the light 32 shown in FIG.
As indicated by a, the light propagates in the light guide 24 while being totally reflected between the flat portion 21 and the interface 28, and finally reaches the inclined portion 22 and is reflected to become the output light 32b.

As shown in FIG. 3C, the light source 26
Of the incident light from, the component that first enters the interface 28 is
The light propagates in the light guide 24 while being totally reflected between the interface 28 and the flat portion 21 of the interface 23, finally reaches the inclined portion 22 and is reflected, and is output from the interface 28 toward the liquid crystal cell 10. .

As can be seen from the above description, almost all the components of the incident light from the light source 26 to the light guide 24 are reflected by the inclined portion 22 and are emitted to the liquid crystal cell 10 through the interface 28. That is, the front light 20 of the present embodiment
Since the light guide 24 having the stepwise interface 23 is provided, the loss of light from the light source 26 is extremely small and the utilization efficiency of the light from the light source is improved.

Next, the conditions 1. of the inclined portion 22 or the flat portion 21 for further improving the utilization efficiency of the light from the light source. ~ 3.
Will be described.

1. About the inclined portion 22 In the light guide 24, the inclined portion 22 of the interface 23 mainly functions as a reflecting surface that reflects the incident light from the light source 26. On the other hand, the flat portion 21 of the interface 23 mainly functions as a transmission surface that transmits the light reflected by the reflection plate 17 provided on the back surface of the liquid crystal cell 10 and the ambient light.

In order for the incident light from the light source 26 to be totally reflected by the inclined portion 22, the following conditions must be satisfied. That is, the light incident on the surface (interface) where substances having different refractive indices come into contact is totally reflected at the interface when the incident angle is equal to or greater than the critical angle. Therefore, in order for the light incident on the inclined portion 22 to be totally reflected by the inclined portion 22, the incident angle θ represented by θ ₁ ≧ θ _c = arcsin (n ₂ / n ₁ ) (Equation 2) _The incident light may be incident on the inclined portion 22 at ₁ .

However, in the above equation 2, θ ₁ is the angle of incidence on the inclined portion 22, n _{1 is} the refractive index of the light guide 24, n _{2 is} the refractive index θ _{c of the} substance in contact with the light guide 24 on the inclined portion 22. : The critical angle of the inclined portion 22.

As described above, if the inclined portion 22 is formed so that the incident angle θ ₁ of the light on the inclined portion 22 satisfies the expression 2, the leakage of light from the inclined portion 22 to the outside of the light guide 24 is prevented. It is suppressed, and the light utilization efficiency can be further improved.

2. Regarding the flat portion 21, it has been described above that the flat portion 21 is a region that mainly transmits light, but as the light that passes through the flat portion 21,
(A) There are reflected light from the liquid crystal cell 10 and (b) ambient light when used in the reflection mode.

The output light of the above (a) is dimmed by the liquid crystal layer 12 of the liquid crystal cell 10, reflected by the reflection plate 17 and incident on the light guide 24 again, and then emitted from the interface 23 to the observer side. At this time, the output is mainly from the flat portion 21. The light reflected by the reflector 17 becomes diffused light. This diffused light is incident on the flat portion 21 at a critical angle or less so that it is transmitted with very little reflection on the flat portion 21 and is transmitted. The critical angle changes depending on the refractive index of the light guide 24, but is approximately 42 ° when PMMA is used as the material of the light guide 24. That is, the liquid crystal cell 1
The output light from 0 is approximately 40 ° on the flat portion 21 of the light guide 24.
It is preferable that the light is incident at the following.

The flat portion 21 does not necessarily have to be parallel to the interface 28. The angle of incidence on the flat portion 21 also depends on the light scattering range of the reflector 17. Therefore, if the characteristics of the reflection plate 17 are also taken into consideration, as shown in FIG. 4, for example, the main range in which light is scattered in the reflection plate 17 is about ± 30 ° with respect to the normal line of the reflection plate 17. If so, if the inclination angle δ of the flat portion 21 with respect to the reflection plate 17 is within approximately ± 10 °, the component 33 of the light reflected by the flat portion 21 can be extremely reduced. In addition, in FIG. 4, in order to make it easy to understand that the flat portion 21 is inclined with respect to the interface 28, the inclination angle δ is shown to be larger than the above preferable range.

Thus, if the flat portion 21 is formed parallel to the interface 28 or inclined within ± 10 °,
Since the incident light from the light source 26 is incident on the flat portion 21 at an incident angle larger than the incident angle on the inclined portion 22, the light incident on the flat portion 21 from the light source 26 is unlikely to leak to the outside and is reflected by the flat portion 21. The amount of light emitted increases. Thereby, the loss of light from the light source is suppressed.

Further, considering the ambient light when used in the reflection mode (b), when the reflection type LCD is used in the reflection mode in which the front light 20 is turned off,
In order to take in sufficient ambient light into the liquid crystal cell 10, it is preferable that the area of the flat portion 21 is large.

3. Arrangement of the inclined portion 22 and the flat portion 21 at the interface 23 Regarding the arrangement of the inclined portion 22 and the flat portion 21 of the interface 23, (a) when the user looks at the reflective LCD from the interface 23 side, Two conditions are important: the area of 22 is small and the area of the flat portion 21 is large, and (b) the total sum of the projections of the inclined portion 22 on the incident surface 25 is large and the total sum of the projections of the flat portion 21 is small. is there.

The condition of (a) above is that the interface 28
It means that the total sum of the projections of the flat part 21 on the is larger than the total sum of the projections of the inclined part 22. Slope 2 to interface 28
The magnitude of the projection of 2 is determined by the inclination angle α of the inclined portion 22 with respect to the interface 28 shown in FIG. Therefore, by adjusting the size of the inclination angle α, the area of the inclined portion 22 seen from the user can be made extremely smaller than the area of the flat portion 21.

Further, the pitch of the slanted portion 22 and the flat portion 21 is matched with the blanking of the scanning line or the bus line of the liquid crystal cell 10, so that the flat portion 21 is arranged over the entire area where the liquid crystal cell 10 is actually displayed. You can
The light utilization efficiency is further improved.

As described above, the condition of (b) is that in order to effectively use the incident light from the light source 26, the incident surface 25
It means that it is preferable that only the inclined portion 22 of the interface 23 is visually recognized when viewed from the normal direction.

Next, the measurement result of the illumination light intensity of the front light 20 will be described. A measurement system as shown in FIG. 5 was used to measure the illumination light intensity of the front light 20. That is, the normal direction of the interface 28 of the front light 20 was set to 0 °, and the light intensity in the range of 0 ° to ± 90 ° was measured by the detector 34.

The results are shown in FIG. As is apparent from FIG. 6, in the front light 20, the light that has entered the light guide 24 from the light source 26 through the incident surface 25 is the light guide 2.
It is understood that the light is emitted in the substantially normal direction of the interface 28 by the action of 4. That is, the front light 20 can allow light from the light source 26 arranged on the side surface of the light guide 24 to enter the liquid crystal cell 10 substantially vertically, and functions as bright auxiliary illumination.

Further, the reflective LCD of the present embodiment has an advantage that brighter display is possible as compared with a transmissive LCD, a self-luminous display such as a CRT or PDP. That is, as shown in FIG. 7A, the light 36 a from the self-luminous display 35 has a traveling direction opposite to that of the ambient light 37. Therefore, the observer recognizes the component 36b obtained by subtracting the ambient light 37 from the light 36a.

On the other hand, the reflective LCD of this embodiment
Then, when used in the illumination mode, as shown in FIG. 7B, the auxiliary light 39a from the front light 20 and the ambient light 37 are reflected by the reflection plate (not shown) of the liquid crystal cell 10. The component 39b corresponding to the sum of the auxiliary light 39a and the ambient light 37 is recognized by the observer. As a result, brighter display is realized not only in a dark place but also in a bright place such as outdoors during the day.

As described above, in the structure according to the present embodiment, since the front light 20 is provided with the step-shaped light guide 24, the utilization efficiency of the light emitted from the light source 26 is improved. Thereby, when the ambient light is not sufficient, sufficient illumination light can be given to the liquid crystal cell 10.
Reflective LCD that can always display brightly regardless of the surrounding environment
Can be provided.

[Second Embodiment] The following will describe another embodiment of the present invention in reference to FIGS. 8 to 11. It should be noted that configurations having the same functions as the configurations described in the above-described first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

The reflective LCD according to this embodiment is shown in FIG.
As shown in FIG. 5, a front light system 51 including the front light 20 (first light guide body) and the wedge-shaped second light guide body 40 described in the first embodiment on the front surface of the liquid crystal cell 10. It is characterized by having.

The second light guide 40 is arranged between the light guide 24 of the front light 20 and the liquid crystal cell 10, and has a slope 41 parallel to the interface 28 of the light guide 24 and the liquid crystal cell. And a bottom surface 42 parallel to the surface of 10. As shown in FIG. 9A, the inclination angle of the inclined surface 41 with respect to the bottom surface 42 is defined by a line 49 connecting the portions where the inclined portion 22 and the flat portion 21 contact with each other in a ridge shape at the interface 23 of the light guide 24.
It is preferably designed to be parallel to the bottom surface 42.

The second light guide 40 is preferably made of a material having at least the same refractive index as that of the light guide 24 which is the first light guide. Needless to say, the second light guide 40 may be made of the same material as the light guide 24. If the light guide 24 and the second light guide 40 are integrally formed by, for example, injection molding, the manufacturing process can be simplified.

In the gap between the light guide 24 and the second light guide 40, spacers (not shown) having a particle size of 50 μm are previously dispersed. As a result, in the gap between the light guide 24 and the second light guide 40, a void 43 having a particle diameter substantially equal to the particle diameter of the spacer is formed.

The space between the bottom surface 42 of the second light guide 40 and the polarizing plate 18 of the liquid crystal cell 10 is filled with a filler (not shown) for matching the refractive indexes of the two. As a result, light attenuation due to reflection at the interface between the second light guide 40 and the polarizing plate 18 is prevented, and the loss of light from the light source is further suppressed.
As the filler, for example, a UV curable resin or methyl salicylate can be used.

Now, the effect of providing the second light guide 40 between the light guide 24 and the liquid crystal cell 10 will be described. As shown in FIG. 9B, in the configuration in which the second light guide 40 is not provided (Embodiment 1), the inclined portion 2 is provided.
The distance l _n (l ₁ , l _{2 in the} drawing) from 2 to the interface 28 as the exit surface to the liquid crystal cell 10 decreases as the distance x _n (x ₁ , x _{2 in the} drawing) from the light source 26 increases. Become.
On the other hand, the front light system 5 of the present embodiment
In FIG. 1, as shown in FIG. 9A, since the second light guide body 40 is provided, the bottom surface 42 of the second light guide body 40, which is the exit surface from the inclined portion 22 to the liquid crystal cell 10, is provided. Distance to
_n is substantially equal regardless of the distance x _n from the light source 26.

That is, the second light guide 40 plays a role of keeping the distance from the inclined portion 22 of the front light 20 to the liquid crystal cell 10 constant, so that the front light system 51 can detect the distance from the light source 26. It functions as a surface light source that emits light with a constant brightness.

Here, in order to confirm the effect of the second light guide 40, as shown in FIG.
Was moved in parallel to the bottom surface 42 of the second light guide 40, and the luminance distribution of the output light of the front light system 51 was measured. The vicinity of the incident surface 25 was set as the measurement start position P _S, and the position on the bottom surface 42 farthest from the light source 26 was set as the measurement end position P _E. The measurement result is shown in FIG.
It is as shown in (a).

Similarly, for comparison, the second light guide 40
In order to measure the luminance distribution of the output light of the configuration (Embodiment 1) in which no is provided, as shown in FIG.
The measurement was performed while moving the detector 44 parallel to the interface 28 of the front light 20. The incident surface 2
The vicinity of 6 is the measurement start position P _S, and the position farthest from the light source 26 at the interface 28 is the measurement end position P _E. The measurement result is as shown in FIG.

As is clear from comparison between FIGS. 11A and 11B, when the second light guide 40 is not provided, as shown in FIG. The pitch p is larger as it is closer to the light source 26 and smaller as it is farther from the light source 26, whereas the front light system 51 of the present embodiment is as shown in FIG.
The pitch p of the luminance peak is the bottom surface 42 of the second light guide 40.
Almost the same throughout, and the brightness peak is also uniform.

As described above, the reflective LCD of this embodiment
The front light system 51 on the front of the liquid crystal cell 10.
The front light system 51 includes a light guide 24 as a first light guide and the liquid crystal cell 10 so that the distance from the inclined portion 22 of the light guide 24 to the liquid crystal cell 10 is constant. By providing the second light guide 40 for
Even when the front light system 51 illuminates the liquid crystal cell 10 evenly and sufficient ambient light cannot be obtained, a bright and even high-quality display is achieved.

[Third Embodiment] The following description will explain still another embodiment of the present invention with reference to FIGS. 5 and 12 to 14. It should be noted that configurations having the same functions as the configurations described in the above-described respective embodiments are denoted by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 12, the reflective LCD of this embodiment has a front light 20 on the front surface of the liquid crystal cell 10.
And a front light system 52 constituted by the second light guide body 45 and the second light guide body 45.

As shown in FIG. 13, the second light guide member 45 is a front scattering plate having a function of scattering the incident light from the light guide member 24 only in the traveling direction side thereof, and has a predetermined shape. An anisotropic scattering plate having a property of scattering only light incident from an angle range and transmitting incident light from a range other than the predetermined angle range. As the second light guide 45 satisfying such a condition, for example, a viewing angle control plate (trade name: Lumisty) manufactured by Sumitomo Chemical Co., Ltd. is commercially available.

The angular range in which the second light guide 45 scatters the incident light preferably completely includes the angular range in which the outgoing light from the light guide 24 is incident. As a result, the light emitted from the light guide 24 can be scattered without difficulty,
It is possible to improve the utilization efficiency of the light from the light source. In addition, the second light guide 45 is anisotropic scattering having a property of scattering only light incident from a predetermined angle range and transmitting incident light from a range other than the predetermined angle range. The second light guide member 4 receives the incident light from outside the predetermined angle range.
Since 5 does not act, the display quality is prevented from being deteriorated by unnecessary scattered light.

In the gap between the light guide 24 and the second light guide 45, spacers (not shown) having a particle size of 50 μm are previously dispersed. As a result, as shown in FIG. 12, in the gap between the light guide 24 and the second light guide 45, a void 46 having a particle diameter substantially equal to the particle diameter of the spacer is formed.

The space between the second light guide member 45 and the polarizing plate (not shown) of the liquid crystal cell 10 is filled with a filler (not shown) that matches the refractive indexes of the two. As a result, light attenuation due to reflection at the interface between the second light guide 45 and the liquid crystal cell 10 is prevented, and the loss of light from the light source is further suppressed.

Now, the measurement result of the illumination light intensity of the front light system 52 will be described. In order to measure the illumination light intensity of the front light system 52, the same measurement system as that used in the first embodiment (see FIG. 5) described above was used. Here, the front light system 52
The normal direction of the second light guide body 45 is 0 °, and 0 ° is ±
In the range of 90 °, the liquid crystal cell 1 of the second light guide body 45
The light intensity from the surface located on the 0 side was measured by the detector 34. The result of the measurement is shown in FIG.

As is clear from FIG. 14, in the front light system 52 of this embodiment, the light emitted from the light guide 24 serving as the first light guide is scattered by the second light guide 45. It can be seen that, as compared with the first embodiment, it has a flat angle characteristic.

As described above, the structure described in the present embodiment is provided with the second light guide 45 that scatters the light emitted from the light guide 24, so that the brightness of the light emitted to the liquid crystal cell 10 is increased. The distribution is averaged, and the liquid crystal cell 10 can be uniformly irradiated.

As the second light guide 45, it is possible to use a hologram or the like in addition to the anisotropic scattering plate.

[Fourth Embodiment] The following description will explain still another embodiment of the present invention with reference to FIGS. It should be noted that configurations having the same functions as the configurations described in the above-described respective embodiments are denoted by the same reference numerals, and the description thereof will be omitted.

As described in the first embodiment, when the viewer-side interface 23 of the light guide 24 is formed by the inclined portion 22 and the flat portion 21, it is reflected by the liquid crystal cell 10. When the light incident on the light guide 24 again passes through the interface 23, image blurring or blurring may occur.

That is, as shown in FIG. 15, the liquid crystal cell 1
The output light 48a from 0 is transmitted not only from the flat portion 21 but also from the inclined portion 22 to the observer side. At this time, the emitted light 48b from the inclined portion 22 and the emitted light 48c from the flat portion 21 are emitted in different directions and intersect with each other, so that blurring or blurring may appear in the image to be displayed.

In order to solve such a problem, the reflective LCD of the present embodiment is provided with a light guide 2 as shown in FIG.
In the interface 23 of No. 4, a metal reflection film 47 (reflection member) that reflects light is added to the surface of the inclined portion 22. As shown in FIG. 16, the metal reflection film 47 reflects all the light incident on the inclined portion 22 regardless of the incident angle. As a result, the light emitted from the interface 23 to the observer side is only the light transmitted through the flat portion 21. As a result, a clear display image without bleeding or blurring can be obtained.

An example of the method of manufacturing the metal reflection film 47 will be described below by taking the case of using aluminum as an example. The material of the metal reflection film 47 is not limited to aluminum, and a metal such as silver may be used.

First, as shown in FIG. 17A, an aluminum film 61 is formed on the entire surface of the interface 23 of the light guide 24 by sputtering. Furthermore, FIG. 17 (b)
As shown in, the photoresist 62 is applied to the surface of the aluminum film 61. Next, through an exposure process, FIG.
As shown in (c), the photoresist 62 is patterned. Then, as shown in FIG. 17D, the aluminum film 61 is etched using the patterned photoresist 62 as a mask. After that, the photoresist 62 is peeled off to form a metal reflection film 47 made of aluminum on the surface of the inclined portion 22 of the interface 23, as shown in FIG.

As described above, since the metal reflection film 47 is provided on the surface of the inclined portion 22, it is possible to increase the inclination angle α of the inclined portion 22 with respect to the flat portion 21, as shown in FIG. is there. For example, as shown in FIG. 18, in the configuration in which the metal reflection film 47 is not provided on the inclined portion 22,
When the inclination angle α is as large as 60 °, the light 49a incident on the inclined portion 22 at an incident angle smaller than the critical angle θ _c is
The light 49b is transmitted through the inclined portion 22 to the viewer side. Such light 49b is not preferable because it deteriorates the display quality.

On the other hand, in the structure of the present embodiment, since the metal reflection film 47 is formed on the inclined portion 22, even if the inclination angle α is made large, the inclined portion 22 like the above light 49b. There is no light that passes through, and all the light is reflected by the inclined portion 22.

As described above, since the inclination angle α of the inclined portion 22 can be made large, the inclined portion 22 is less visible when viewed from the normal direction of the flat portion 21,
There is an advantage that the display quality can be improved.

As shown in FIG. 19, if a black matrix 47b (light-shielding member) for preventing reflection of ambient light is laminated on the surface of the metal reflection film 47, ambient light is reflected to the observer side. Can be prevented. This prevents deterioration of display quality due to reflection of ambient light to the observer side, which is more preferable.

As described above, the front light 20 according to the present embodiment is characterized in that the metal reflection film 47 for eliminating the transmitted light from the inclined portion 22 to the observer side is formed in the inclined portion 22. I am trying. As a result, the light emitted from the interface 23 to the observer side is only the light emitted from the flat portion 21, and therefore, in the reflective LCD having the front light 20 on the front surface of the liquid crystal cell 10, there is no bleeding or blurring. It is possible to obtain a clear display image.

[Fifth Embodiment] The following description will explain still another embodiment of the present invention with reference to FIG. 15 and FIGS. 20 to 22. It should be noted that configurations having the same functions as the configurations described in the above-described respective embodiments are denoted by the same reference numerals, and the description thereof will be omitted.

The reflective LCD according to this embodiment is shown in FIG.
As shown in FIG.
The front light system 53 configured by the front light 20 described above and the optical compensation plate 64 (compensation means) provided on the interface 23 of the front light 20.
It is characterized by having.

In the optical compensating plate 64, a bottom surface 64a which is a surface facing the light guide 24 of the front light 20.
As shown in FIG. 20, has a stepped shape complementary to the interface 23 of the light guide 24. That is, on the bottom surface 64 a, the inclined portion 65 parallel to the inclined portion 22 is formed at a position facing the inclined portion 22 of the light guide 24, and at the position facing the flat portion 21 of the light guide 24, the flat portion 21 is formed. Is formed with a flat portion 66 parallel to. On the other hand, in the optical compensation plate 64, the surface 64 b, which is the surface located on the observer side, has the interface 28 of the light guide 24.
Is formed as a plane parallel to.

The optical compensation plate 64, like the light guide 24,
For example, it can be produced by injection molding using PMMA. As described above, the optical compensation plate 64 and the light guide 24 are arranged so that their inclined portions and flat portions face each other, and are bonded via a spacer (not shown) having a particle diameter of about 20 μm. As a result, the air layer 6 having a substantially uniform thickness is provided between the bottom surface 64 a of the optical compensation plate 64 and the interface 23 of the light guide 24.
7 will intervene.

By providing the optical compensator 64 on the front surface of the light guide 24 and the air layer 67 existing between the light guide 24 and the optical compensator 64, the following effects can be obtained. To be

That is, in FIG.
As described with reference to FIG. 5, the lights 48 a and 48 a that are incident on the light guide 24 again from the liquid crystal cell 10 are
Even if they proceed in the same direction inside 4, by passing through the inclined portion 22 or the flat portion 21 of the interface 23, respectively,
The light is emitted from the interface 23 of the light guide in different directions, causing blurring or blurring of the image.

On the other hand, in the front light system 53 of this embodiment, as shown in FIG.
Light 68a / 69 that is incident on the light guide 24 from 0 in the same direction
After being emitted from the light guide 24, a is refracted at the bottom surface 64a serving as the interface between the air layer 67 and the optical compensation plate 64, and becomes light that travels in the same direction again, as shown as light 68b and 69b. The light is emitted from the surface 64b of the optical compensation plate 64 in the same direction. As a result, a clear image without bleeding or blurring can be obtained when viewed from the observer side.

In addition to the above-mentioned optical compensation plate 64, FIG.
As shown in FIG. 2A, the optical compensation plate 71 formed in a flat plate shape may be arranged on the front surface of the light guide 24. in this case,
As shown in FIG. 22B, the optical compensation plate 71 has a region 7 into which the light emitted from the inclined portion 22 of the light guide 24 is incident.
1a and the region 71b on which the light emitted from the flat portion 21 of the light guide 24 is incident have refractive indexes different from each other, so that the emission angle of light from the respective surfaces of the regions 71a and 71b to the observer side. θ _a · θ _b are substantially equal. Alternatively, the region 71a may be formed of a member having a diffractive function (for example, a diffractive element) in order to diffract the light transmitted through the region 71a in the same direction as the light transmitted through the region 71b.

Alternatively, as shown in FIG. 22C, in the optical compensating plate 71, the black mask 7 for blocking the light incident on the region where the light emitted from the inclined portion 22 of the light guide 24 enters.
The light emitted from the inclined portion 22 may be prevented from reaching the observer side by being formed of 1c.

As described above, according to the configuration of this embodiment, the inclined portion 22 and the flat portion 2 of the interface 23 of the light guide 24 are formed by the optical compensation plate 64 (or the optical compensation plate 71).
By aligning the emission direction of the light from each of 1, the reflective LC that enables clear display without blurring or blurring.
D is realized.

[Sixth Embodiment] The following description will explain still another embodiment of the present invention with reference to FIGS. 20 and 23 to 26. In addition, the configuration having the same function as the configuration described in each of the above-described embodiments,
The same reference numerals are given and the description thereof is omitted.

The reflective LCD according to the present embodiment is obtained by adding a touch panel function to the front light system 53 (see FIG. 20) of the reflective LCD described in the fifth embodiment.

In order to realize the above-mentioned touch panel function, the reflection type LCD of this embodiment is provided with a transparent electrode 72 made of, for example, ITO on the bottom surface 64a of the optical compensation plate 64 as shown in FIG. The inclined portion 22 of the light body 24 is provided with a reflective electrode 73 made of a material that reflects light and has conductivity, such as aluminum. The transparent electrode 72 and the reflective electrode 73 constitute a position detecting means.

The lower part of FIG. 24 is a plan view showing the shape of the reflective electrode 73 when viewed from the direction normal to the flat portion 21 of the light guide 24. As shown in FIG. 24, since the reflective electrode 73 is provided on the entire surface of the inclined portion 22 of the light guide 23, it has a stripe shape when viewed from the normal direction of the flat portion 21 of the light guide 24. Further, as shown in FIG. 25, the transparent electrodes 72 formed on the optical compensation plate 64 are also formed in a stripe shape, and the reflective electrodes 73 and the transparent electrodes 72 form a matrix orthogonal to each other.

A plastic bead spacer (not shown) having a particle size of about 10 μm is dispersed between the reflective electrode 73 of the light guide 24 and the transparent electrode 72 of the optical compensation plate 64. Voids are formed that are approximately equal in diameter.

The optical compensating plate 64 has flexibility and is shown in FIG.
As shown in FIG. 6, by being pressed by the pen 74, the transparent electrode 72 and the reflective electrode 73 come into contact with each other. The recognition of the coordinates pressed by the pen 74 is performed as follows. Figure 25
As shown in FIG. 7, the transparent electrode 72 and the reflective electrode 73 are scanned with a signal line-sequentially so that the contact point 7
The X coordinate and the Y coordinate of 5 are detected, and the coordinates of the position pressed by the pen 74 can be specified in the plane of the touch panel.

Here, the structure in which the stripe-shaped transparent electrode 72 is formed on the optical compensation plate 64 has been described as an example, but the transparent electrode may be formed on the entire bottom surface 64a of the optical compensation plate 64. . However, as described above, forming the transparent electrode 72 in a stripe shape has an advantage of high light utilization efficiency.

As described above, according to the structure of the present embodiment, the optical compensator 64 functions as a touch panel, so that a reflective LCD capable of pen input with respect to the content displayed in the liquid crystal cell 10 is provided. It becomes possible.

[Seventh Embodiment] The following description will explain still another embodiment of the present invention with reference to FIGS. 27 to 30. It should be noted that configurations having the same functions as the configurations described in the above-described respective embodiments are denoted by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 27, the front light included in the reflection type LCD according to the present embodiment has, in addition to the structure described in the first embodiment, an incident surface of the light source 26 and the light guide 24. 25 between the light source 26 and the incident surface 2
5, a prism sheet 81 and a diffusion plate 82 are provided as a light control means for controlling the spread angle of the light incident on the light source 5. In addition, here, the prism sheet 8
The apex angle of the prism 1 is 100 °. In addition, the light guide 2
4 and the polarizing plate 18 of the liquid crystal cell 10 are filled with a filler 84 for relaxing the difference in refractive index.

The light source 26 is realized by, for example, a fluorescent tube, but the output light from the fluorescent tube does not have a particular directivity and is randomly generated. For this reason, there is light that enters the inclined portion 22 of the light guide 24 at an angle larger than the critical angle, and there is a risk that leakage light from the inclined portion 22 will cause deterioration in display quality.

Considering that the refractive index of PMMA which is preferably used as the material of the light guide 24 is about 1.5,
Light having an incident angle to the inclined portion 22 that is equal to or less than the critical angle (about 42 °) becomes leakage light. In order to eliminate such leaked light, the spread angle of the output light from the light source 26 may be controlled in advance so that the incident light that becomes the leaked light component does not enter the light guide 24.

Here, as shown in FIG. 28, the inclination angle of the inclined portion 22 with respect to the interface 28 is α. Note that FIG.
For the sake of convenience of explanation, the positional relationship among the inclined portion 22, the interface 28, and the incident surface 25 of the light guide 24 is extracted and shown, and the light guide 24 actually has such a shape. Do not mean.

Further, the spread angle of the light incident from the incident surface 25 of the light guide 24 is ± β, and the critical angle of the inclined portion 22 is θ _c.
Then, the incident angle θ of the light on the inclined portion 22 is represented by θ = 90 ° −α−β.

Therefore, the condition for the light incident on the inclined portion 22 from the incident surface 25 not to pass through the inclined portion 22 is θ _c <θ = 90 ° −α−β, that is, β <90 ° − (θ _c + α ) (Expression 3)

In this embodiment, the inclination angle α of the inclined portion 22 is 10 °. Since this and the critical angle θ _c are 42 °, β <38 ° is derived based on the above equation 3.

The output light from the light source 26 is once diffused by the diffusion plate 82 and then enters the prism sheet 81. The prism sheet 81 has a function of condensing diffused light in a specific angle range. When the apex angle of the prism is 100 °, the diffused light is scattered within an angle range of about ± 40 ° as shown in FIG. Focus. The light collected in the angle range of about ± 40 ° is guided by the light guide 2.
4 is further condensed by refraction at the incident surface 25 to become a spread light in the range of about ± 25.4 °. That is, it can be seen that the divergence angle of the light incident from the incident surface 25 is sufficiently within the above range of β <38 °, and leak light from the inclined portion 22 does not occur.

As described above, the reflection type L according to this embodiment is
In the CD, the prism sheet 81 is installed between the light source 26 and the incident surface 25 of the light guide 24 in order to suppress the spread of the light from the light source. It is further improved.

In this embodiment, the prism sheet 8 is used.
Although the apex angle of 1 is 100 °, it is not necessarily limited to this angle. Further, the prism sheet 81 is used as the light control means for limiting the spread of the light from the light source, but the invention is not limited to this as long as the same effect can be obtained, and for example, a collimator or the like may be used. Further, as shown in FIG. 30A, the same effect can be obtained by a configuration in which the periphery of the light source 26 is covered with an ellipsoidal mirror 98 and the light source 26 is installed at the focal point of the ellipsoidal mirror 98. In addition, SID DI
As shown in GEST P.375 (1995), FIG.
The spread of the incident light from the light source 26 may be controlled using the light pipe 99 shown in (b).

[Embodiment 8] FIG. 1, FIG. 3, and FIG. 31 to FIG. 3 of still another embodiment of the present invention.
The following is a description based on item 3. It should be noted that configurations having the same functions as the configurations described in the above-described respective embodiments are denoted by the same reference numerals, and the description thereof will be omitted.

The reflective LCD according to this embodiment is the same as the reflective LCD described in each of the above-described embodiments, because of the difference in refractive index between the front light (or front light system) and the liquid crystal cell 10. It is filled with a filler (matching agent) that prevents light from being attenuated.

Here, the reflection type L described in the first embodiment is used.
Description will be given by taking as an example a configuration in which the above-mentioned filler is applied to a CD. In the first embodiment, as described with reference to FIG. 1, the light guide 24 of the front light 20 has the liquid crystal cell 1
It is laminated on the polarizing plate 18 of No. 0 through a spacer having a particle size of about 50 μm. As a result, a void 29 is formed between the liquid crystal cell 10 and the light guide 24 with a uniform thickness that is approximately equal to the particle size of the spacer.

In the reflective LCD of this embodiment, the voids 29 are filled with a filler 84 as shown in FIG. As the filler 84, for example, a UV curable resin or methyl salicylate can be used. As a result, the interface 28 of the light guide 24 comes into contact with not the air but the filler 84 having a refractive index higher than that of the air. The filler 84 preferably has a refractive index substantially equal to that of the light guide 24.

As described above, the case where the interface 28 of the light guide 24 is in contact with the filler 84 and the case where the interface 28 of the light guide 24 is in contact with air as in each of the above-described embodiments. , The behavior of light at the interface 28 is different.

Of the incident light from the light source 26, FIG.
As shown in (a), the component that is substantially vertically incident on the incident surface 25 is directly incident on the inclined surface 22 from the incident surface 25, reflected, and then passes through the interface 28 and the filler 84 to pass through the liquid crystal cell 10.
Incident on. The behavior of light at the interface 28 at this time is as follows.
This is the same as when the interface 28 is in contact with air (see FIG. 3A).

On the other hand, of the incident light from the light source 26, FIG.
As shown in FIG. 1 (b), among the components that are first incident on the interface 23 from the incident surface 25, the flat portion 21 such as the light 85 a is included.
There is also one that is incident on the interface 28 after being reflected at. Of such light 85a and incident light from the light source 26, FIG.
As shown in (c), the component that first enters the interface 28 from the incident surface 25 has no effect on the interface 28 because the interface 28 is in contact with the filler 84 having a refractive index substantially equal to that of the light guide 24. Transparent without receiving.

These lights are emitted by the liquid crystal layer 12 of the liquid crystal cell 10.
Will be incident at a very large angle of incidence,
Since the light is reflected by the reflection plate 17 and re-enters the interface 28 of the light guide 24 at the above-mentioned large incident angle, it does not reach the observer.

However, in order to improve the utilization efficiency of the light from the light source, it is preferable to eliminate the component directly incident on the interface 28 from the light source 26. Therefore, as shown in FIG. 32, by tilting the incident surface 25 so that the incident surface 25 and the interface 28 form an obtuse angle, it is possible to eliminate a component that is directly incident on the interface 28 from the incident surface 25.

The angle γ formed by the incident surface 25 and the interface 28 is
As shown in FIG. 33, considering the spread angle β after the light from the light source 26 is incident on the incident surface 25, it is more preferable that the magnitude of γ be ≧≧ 90 ° + β. As a result, almost all of the light source light that has entered from the incident surface 25 enters the interface 23, and the utilization efficiency of the light source light can be further improved.

[Ninth Embodiment] The following will describe still another embodiment of the present invention in reference to FIG. In addition, the same reference numerals are given to the configurations having the same functions as the configurations described in the respective embodiments,
The description is omitted.

The reflective LCD according to the present embodiment is characterized in that the front light 20 is formed in a lid shape that can be opened and closed with respect to the liquid crystal cell 10.

In each of the above-described embodiments, various forms of the front light or the front light system as the front lighting device have been described. Particularly, as in the configuration described in the fourth embodiment, the inclination of the light guide 24 is inclined. When the portion 22 is provided with the metal reflection film 47, the metal reflection film 47 prevents the ambient light from entering the light guide 24. Therefore, the ambient environment is not so dark as to require the reflective LCD to be used in the illumination mode, but the display in the reflective mode is not preferable especially in the situation where the ambient light amount is not enough to be used in the reflective mode. May become dark.

Therefore, as shown in FIG. 34, in the reflective LCD 91 of the present embodiment, the front light 20 is fixed to the liquid crystal cell 10 by fixing one side of the front light 20 with, for example, a hinge (not shown). It is openable and closable. The front light 20 is formed as an inner lid that can be opened and closed independently of a lid 92 that covers the liquid crystal cell 10 and the front light 20.

Therefore, when the reflective LCD 91 is used in the illumination mode, the front light 2 is placed on the surface of the liquid crystal cell 10.
When the reflective LCD 91 is used in the reflective mode when the reflective LCD 91 is used in a state in which 0 is covered, that is, only the lid 92 is opened,
The front light 20 can be used with the liquid crystal cell 10 open.

As a result, when used in the reflection mode, a reflection type LCD which can always realize a bright display without light loss due to the front light 20 is realized.

In the above description, at least a part of the front light 20 is fixed to the liquid crystal display device. However, the front light 20 is completely unitized and can be attached to and detached from the liquid crystal cell 10. Also good. However, in this case, it is necessary to consider how to store the front light 20 when it is removed from the liquid crystal cell 10.

Although the reflective LCD provided with the front light 20 in the shape of an inner lid has been described here, the front light system described in each of the above embodiments may be provided in the shape of an inner lid. .

[Embodiment 10] The following description will discuss still another embodiment of the present invention with reference to FIGS. 35 and 36. It should be noted that configurations having the same functions as the configurations described in the above-described respective embodiments are denoted by the same reference numerals, and the description thereof will be omitted.

In each of the above-described embodiments, the reflection type LCD having a structure in which the front light or the front light system as the front illumination device and the reflection type liquid crystal cell as the object to be illuminated are combined has been described. However, the front light or the front light system as the front lighting device of the present invention is not used only in combination with the reflective liquid crystal cell. For example, as shown in FIG. 35, the illumination device 95 according to the present embodiment is a device in which the front light or the front light system described in each of the above-described embodiments is formed as an independent unit, and various objects are provided. It is possible to illuminate.

For example, the illuminating device 95 can be used by being arranged on a book 96 as shown in FIG. As a result, as shown in FIG. 36, it is possible to illuminate only a region substantially directly under the illumination device 95, and thus it is possible to avoid annoying other people when reading in a bedroom, for example. is there.

The embodiments described above do not limit the present invention, and various modifications can be made within the scope of the invention. For example, as the material of the light guide, PMMA
However, a material such as glass, polycarbonate, polyvinyl chloride, or polyester may be used as long as it can uniformly guide light without attenuation and has an appropriate refractive index. Further, the dimensions and the like of the inclined portion and the flat portion of the light guide body described above are merely examples, and can be freely designed within a range in which equivalent effects can be obtained.

Further, as the liquid crystal cell, various LCDs such as a simple matrix type LCD and an active matrix type LCD can be used. Further, in the above, an ECB mode (single polarizing plate mode) liquid crystal cell using one polarizing plate that also serves as a polarizer and an analyzer is used, but in addition, PDLC or PC-GH without a polarizing plate is used. Etc. may be applied.

[Embodiment 11] The following description will discuss still another embodiment of the present invention with reference to FIGS. 37 to 48. It should be noted that configurations having the same functions as the configurations described in the above-described respective embodiments are denoted by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 37, the reflective LCD of the present embodiment is similar to that of the first embodiment in that the front face of the reflective liquid crystal cell 10a is provided with the front light 20a. The antireflection film (antireflection film) 13, which is the second light guide (optical means), is arranged between the reflective liquid crystal cell 10a and the front light 20a, and is formed in the light guide 24a. Different from the first embodiment, the width (pitch) of the flat portion 21 and the inclined portion 22 is different, and the reflection electrode (reflection plate) 17a is formed inside the reflection type liquid crystal cell 10a. There is.

First, the front light 20a will be specifically described. The front light 20a is mainly composed of the light source 26 and the light guide 24 as in the first embodiment.
a, and the incident surface 25 of the light guide 24a.
A light source 26 as a linear light source covered with a reflecting mirror 27 is provided so as to be in contact with.

The interface (first emission surface) 28 on the liquid crystal cell 10a side of the light guide 24a is formed flat, and the interface (second emission surface) 23 facing this interface is parallel to the interface 28. Alternatively, the flat portion 21 formed substantially parallel to the flat portion 21 and the inclined portion 22 inclined in the same direction with respect to the flat portion 21 at a constant angle
And are formed alternately.

As described above, the light guide body 24a is similar to the light guide body 24 in the first embodiment in that, as shown in FIG. It is shaped like a staircase that goes down as it goes away.

Here, the shape of the light guide 24a will be described in more detail with reference to FIGS. 38 (a) to 38 (c). FIG. 38 (a) is a plan view of the light guide seen from above in the normal direction of the flat portion, and FIG. 38 (b) is a side view of the light guide seen from the direction normal to the incident surface. , FIG. 38 (c)
[FIG. 4] is a cross-sectional view of the light guide body taken along a plane perpendicular to both the incident surface and the interface.

As the material of the light guide 24a, an acrylic plate is used in this embodiment, and the light guide 24a can be processed into a step shape by molding the acrylic plate. The light guide 24a has a width W in the present embodiment.
= 75 mm, length L = 170 mm, thickness h ₁ of incident surface 25 = 2.0 mm, width w _{1 of} flat portion 21 = 0.2 mm
And Further, by setting the step h ₂ of the inclined portion 22 to 10 μm and the inclination α with respect to the flat portion 21 to be 45 °, the width w ₂ of the inclined portion is about 10 μm.

Furthermore, in this embodiment, the light guide 24a is used.
Is in the direction away from the incident surface 25, that is, the light source 26.
The width w of the flat portion 21₁And the width w of the inclined portion 22₂With
Sum w ₃= 0.21 mm gradually decreases
Have In the structure of the flat portion 21 and the inclined portion 22,
In addition to FIG. 38 (a) to (c), FIG.
It will be described more specifically based on this. The light guide 24a
The light source 2 in the direction away from the light source 26 in
The direction in which the longitudinal direction of 6 is the normal is hereinafter referred to as the first direction.
38 and 39, and is indicated by an arrow A.

As shown in FIG. 39, the flat portion 21 and the inclined portion 22 are combined one by one to form one set, and the flat portion 21 and the inclined portion 22 from the side closest to the light source 26 are set in the first block. Let B ₁ . And this first block B ₁
The distance w ₄ in the first direction is 21 mm.

The second block B _2, which is the next 100 sets of blocks, is formed so that the interval w ₄ is 20 mm. Furthermore, the interval w in the next third block B _3
4 is formed to be 19 mm, the distance w ₄ in the fourth block B ₄ formed to have a 18 mm, to form a gap w ₄ in the fifth block B ₅ such that the 17 mm.

Therefore, in this embodiment, the light guide 24a is formed.
In the above, in each block from the end surface on the light source 26 side to the end surface on the side where the light source 26 is not arranged along the first direction,
The distance w ₄ between the blocks is reduced by 1 mm. That is, as the distance from the light source 26 increases, the flat portion 21
Pitch and pitch sum of the inclined portion 22 (the sum w ₃ of the width w ₂ of width w ₁ and the inclined portion 22 of the flat portion 21), 10 [mu] m of
It is formed so as to decrease by (1/100 mm). Note that, in FIGS. 38A to 38C, the reduction of the pitch of the flat portion 21 and the inclined portion 22 is not shown for convenience of description.

In the light guide 24a, the inclined portion 22 mainly functions as a minute light source portion which is a surface for reflecting the light from the light source 26 toward the interface 28. on the other hand,
The flat portion 21 mainly functions as a surface for transmitting the reflected light to the observer side when the illumination light from the front light 20a returns from the liquid crystal cell 10a as the reflected light. The operation of each of these parts is the same as in the first embodiment.

Further, the light guide 24a in the front light 20a has, in addition to this stepwise structure, a pitch of one set for every 100 sets of the flat portion 21 and the inclined portion 22 reduced by, for example, 10 μm, that is, A configuration is provided in which the pitch of the stairs is reduced as the distance from the light source 26 increases. Therefore, as shown in FIG. 40A, the number of the inclined portions 22 per unit area increases as the distance from the light source 26 increases.

Incident light from the incident surface 25 from the light source 26 is reflected by the inclined portion 22 acting as a minute light source portion, but the number of inclined portions 22 per unit area increases as the distance from the light source 26 increases. , Front light 20a
The reflection type liquid crystal cell 10a which is an illuminated object illuminated by
The brightness increases as the position moves away from the light source 26. Normally, the brightness tends to lower as the position is farther from the light source 26. Therefore, with the configuration of the light guide 24a of the present embodiment, the interface 28 (first emission surface) is further away from the light source 26. It is possible to cancel the decrease in brightness due to this and efficiently guide the light from the light source 26 to the entire illuminated object at a high angle. As a result, it is possible to average the luminance distribution on the interface 28 side, which is the interface on the illuminated object side (first emission surface).

On the other hand, as shown in FIG. 40B, in the conventional front light 120 in which the light guide 124 is formed in a wedge-shaped flat plate shape, the light source 26 is incident on the incident surface 125.
The incident light incident on is reflected by the interface 123 as it is. Therefore, the brightness on the first emission surface (the interface 128 in the front light 120) is equal to that of the light source 2.
It decreases as it goes away from 6.

Further, as shown in FIG. 41, the luminance distribution state on the first exit surface is as shown in FIG.
Compared to the graph F showing the brightness distribution of No. 20, the graph E showing the brightness distribution of the front light 20a of the present embodiment is substantially constant even at a position where the distance from the light source 26 is large. Therefore, the front light 20 of the present embodiment
It can be seen that a is more excellent in the uniformity of the luminance distribution on the first emission surface (interface 28).

In the light guide 24a having the above structure, since the pitch of the steps is 0.21 mm, the black matrix formed around the pixels of the reflection type liquid crystal cell 10a corresponding to the light guide 24a. The pitch and the pitch of the groove of the inclined portion 22 are deviated. As a result, since it is possible to suppress the generation of moire fringes due to the interference between the black matrix and the inclined portion 22, it is possible to improve the display quality of the obtained reflective LCD. Note that this point will be described later.

The results of the emission angle characteristics of the light guide 24a are shown in FIG. 42. In the graph G on the reflective LCD side (interface 28 side) which is the object to be illuminated, the light receiving angle is -10. 2,000c with a peak between ° and -5 °
The brightness is increased to the extent that it reaches d / m ² . On the other hand, in the graph H on the observer side (interface 23 side), when the light-receiving angle is -60 °, the maximum luminance is 500 cd / m ² , and the angle at which the reflective LCD is observed is 0 °. The luminance is 100 cd / m ² or less in the vicinity.

Thus, the light from the light source 26 arranged on the end face of the light guide 24a can be emitted from the interface 28 at an angle substantially perpendicular to the object to be illuminated (reflection type LCD). At the same time, there is almost no light leakage on the observer side, which is the interface 23 side, and the light from the light source 26 can be efficiently guided to the illuminated object at a high angle.

In this embodiment, a fluorescent tube is used as the light source 26, but the light source 26 is not limited to this. For example, an LED (light emitting diode), an EL element, or a tungsten lamp is used. Can be used.

Next, the liquid crystal cell 10a will be described. As shown in FIG. 37, the liquid crystal cell 10a has the same basic configuration as the liquid crystal cell 10 of the first embodiment, but the reflector 17a is used. Is different in that it is formed in the liquid crystal cell 10a.

As shown in FIG. 43, the liquid crystal cell 10a is composed of a pair of electrode substrates 11a and 11c which form a liquid crystal layer 12.
And the retardation plate 49 and the polarizing plate 18 on the electrode substrate 11a side which is the display surface side.
Although only one retardation plate 49 (not shown in FIG. 37) is provided in FIG. 43, it may be two or more, or may not be provided.

In the electrode substrate 11a, the color filter 38 is provided on the glass substrate 14a having a light transmitting property, the transparent electrode 15a (scanning line) is provided thereon, and the liquid crystal is formed so as to cover the transparent electrode 15a. An alignment film 16a is formed. An insulating film or the like may be formed on the electrode substrate 11a if necessary. The color filter 38 is not shown in FIG.

On the other hand, the electrode substrate 11c is the glass substrate 14
An insulating film 19 is formed on b, a reflective electrode (reflecting plate) 17a is further formed thereon, and a liquid crystal alignment film 16b is formed so as to cover the reflective electrode 17a. A plurality of uneven portions are formed on the surface of the insulating film 19, and a plurality of uneven portions are also formed on the surface of the reflective electrode 17a covering the insulating film 19.

The reflection electrode 17a serves both as a liquid crystal drive electrode for driving the liquid crystal layer 12 and as a reflection plate. As the reflective electrode 17a, aluminum (A
l) A reflective electrode is used. In addition, the insulating film 19
Is formed of an organic resist, and contact holes and irregularities in this insulating film 19 are formed by photolithography described later. The glass substrate 14a
14b, transparent electrodes 15a and 15b, and liquid crystal alignment film 1
The material and forming method of 6a and 16b are the same as those in the first embodiment.

Regarding the method of forming the electrode substrate 11c,
This will be described in more detail based on FIGS. 44 (a) to 44 (e). First, as shown in FIG. 44A, the glass substrate 14
An organic resist is applied on the entire surface of the substrate b and baked to form the insulating film 19. Thereafter, as shown in FIG. 44B, the insulating film 19 is irradiated with the ultraviolet rays 30a through the mask 30. Thereby, the ultraviolet rays 30 in the insulating film 19
The irradiation portion of a is removed, and as shown in FIG. 44C, the irradiation portion of the ultraviolet rays 30a is formed in a predetermined pattern.

Next, as shown in FIG. 44 (d), the insulating film 19 formed in a predetermined pattern is subjected to heat treatment at 180 ° and baked to cause heat drop in the organic resist. Let Due to this heat sag, the uneven portion 19a
To form.

Finally, as shown in FIG. 44 (e), aluminum (Al) is vacuum-deposited so as to cover the uneven portion 19a. As a result, the reflective electrode 17a having the uneven portion formed on the surface is formed along the uneven portion 19a. Note that in FIGS. 44A to 44E, the insulating film 1
9 is formed as an uneven portion 19a having a predetermined pattern, but as shown in FIGS. 37 and 43, the uneven portion may be formed only on the surface of the insulating film 19.

The electrode substrate 11c and the electrode substrate 11a thus obtained are arranged so that the liquid crystal alignment films 16a.
6b are opposed to each other, and the rubbing treatment directions are arranged antiparallel to each other, and they are bonded together using an adhesive. Further, glass bead spacers (not shown) having a particle diameter of 4.5 μm are previously dispersed between the electrode substrates 11a and 11c in order to make the intervals of the voids formed by the electrode substrates 11a and 11c uniform. ing. Then, the liquid crystal layer 12 is formed by introducing liquid crystal into the voids by vacuum deaeration. The material of the liquid crystal layer 12 is the same as that of the first embodiment.

The reflective liquid crystal cell 10a of the present embodiment is manufactured as described above, but the manufacturing steps and manufacturing conditions other than those described above are the same as those of the reflective liquid crystal cell 10 of the first embodiment. Therefore, it is omitted.

The reflective electrode 17 on the electrode substrate 11c.
The pattern of the uneven portion formed on the surface a (that is, the pattern of the uneven portion 19a of the insulating film 19) is irregularly formed to diffusely reflect incident light incident on the reflective liquid crystal cell 10a in a specific direction. Is formed.

In the uneven portion of the insulating film 19, it is preferable that the difference between the peak of the convex portion and the bottom surface of the concave portion is within the range of 0.1 μm to 2 μm. When the difference between the peak of the convex portion and the bottom surface of the concave portion in the concave-convex portion is within this range, incident light can be diffused without affecting the alignment of liquid crystal molecules and the cell thickness of the liquid crystal cell.

[0187] The reflective electrode 17a thus formed
4 is compared with the reflection characteristic of a standard white plate (MGO) that exhibits a diffuse reflection characteristic almost similar to that of paper.
It will be described based on 5. Above MGO (and paper etc.)
Indicates a reflection characteristic showing isotropicity as shown by a broken line graph M in the figure. On the other hand, the reflective electrode 17a
(MRS) is ± 30 as shown by the solid line graph N in the figure.
It has a diffuse reflection characteristic showing directivity at an angle of °.

Even if light is incident on the reflection type liquid crystal cell 10a having such a reflection electrode 17a from a direction other than the regular reflection direction, an image can be observed. The reflection characteristics of the reflection electrode 17a are not limited to the characteristics shown in FIG. 45, and the design of the reflection electrode 17a can be changed as appropriate to meet the type of equipment used for the reflection type LCD. It is possible to correspond to the characteristics.

Further, since the reflective electrode 17a is formed so as to be adjacent to the liquid crystal layer 12 in the reflective liquid crystal cell 10a, the reflective plate is in contact with the back side of the reflective liquid crystal cell 10a (the light guide 24a). Compared with the case where it is formed on the surface opposite to the side surface), the occurrence of parallax due to the glass substrate 14b can be eliminated. Therefore, the obtained reflective LCD
In the above, it is possible to suppress the double reflection of the image. Moreover, the configuration of the reflective liquid crystal cell 10a can be simplified.

The reflective electrode 17 in this embodiment is the same.
As shown in FIGS. 37 and 43, a may be a polarization mode in which the reflective liquid crystal cell 10a has a polarizing plate 18, and as shown in FIG. It may be a reflective liquid crystal cell (without a polarizing plate). The basic structure of this reflective liquid crystal cell is almost the same as that of the reflective liquid crystal cell 10a, and therefore detailed description thereof is omitted.

Next, the pixel structure arranged in the liquid crystal cell 10a will be described. As shown in FIG.
The reflective liquid crystal cell 10a is the reflective liquid crystal cell 10a.
A plurality of scanning lines 54 are formed along the longitudinal direction of the, and a plurality of signal lines 55 are formed in a direction orthogonal to the direction in which the scanning lines 54 are formed. And
The plurality of pixels 56 ... Corresponding to the grid pattern formed by the scanning lines 54 and the signal lines 55.
Are formed.

One pixel 56 includes red (R), green (G), and
Pixel electrode 5 corresponding to three blue (B) color filters
It consists of 6a. These pixel electrodes 56a are arranged in the order of R, G, B along the direction in which the scanning lines 54 are formed.

As the shape of the reflection type liquid crystal cell 10a, in the present embodiment, a diagonal 6.5-inch size (vertical W _L =
58 mm, width L _L = 154.5 mm), 54 scanning lines X
m = 240, and the number of signal lines 55 is Yn = 640. The pitch P _{L of the} pixels 56 arranged in the reflective liquid crystal cell 10a is 0.24 mm (R, G, B). A black matrix (not shown) (hereinafter abbreviated as BM) is formed around the pixels 56 so as to have a width of 8 μm.

In the reflective LCD according to this embodiment,
The reflective liquid crystal cell 10a and the front light 20a described above.
It is a combination of and. Here, in the front light 20a, the pitch of the flat portion 21 and the inclined portion 22 of the light guide 24a is 0.21 mm as described above, which is smaller than the pitch of the scanning lines 54, that is, the BM. Therefore, B in the reflective liquid crystal cell 10a is
The pitch of M and the pitch of the groove of the inclined portion 22 can be shifted. When these pitches are deviated, it is possible to suppress the generation of moire fringes due to the interference between the BM and the inclined portion 22. Therefore, the display quality of the obtained reflective LCD can be improved.

In the configuration of the light guide 24a described above, the pitch of the flat portions 21 and the inclined portions 22 is smaller than the pitch of the scanning lines 54 ...
It may be larger than the pitch. That is, in order to suppress the generation of moire fringes, the pitch of the grooves of the inclined portion 22 and the pitch of the BM may be deviated.

Here, the width w ₁ of the flat portion 21 and the inclined portion 22
The sum w ₃ of the width w ₂ and the pitch of the groove of the inclined portion 22 of the.
Further, the BM is formed so as to shield the scanning lines 54 and the signal lines 55. However, since the scanning lines 54 are parallel to the groove of the inclined portion 22, the scanning lines 54 ... The pitch P ₁ is the pitch of BM.

[0197] For the pitch of the pitch and BM of the grooves of the inclined portion 22 is shifted, the above w ₃ and P ₁ does not coincide (w ₃ ≠ P ₁₎ it is sufficient if the state, and this w ₃ The relationship with P ₁ is that w ₃ has a width larger than twice P ₁ (w ₃ > 2P ₁ ), or w ₃ has a width smaller than half P ₁ (w ₃ <2 1/2 P ₁ ) is particularly preferable.

If the relationship between w ₃ and P ₁ deviates from the above range, the groove pitch of the inclined portion 22 and the BM pitch may deviate from each other. It is possible to see. Therefore, it is not preferable because the generation of moire fringes cannot be effectively suppressed.

[0199] The width w ₂ and the width w ₁ and the inclined portion 22 of the flat portion 21 in the present embodiment, these w ₁ and w ₂ sum of w _3, such angle of the inclined portion 22, the above numerical The present invention is not limited to this, and may be formed according to the pixel structure of the reflective liquid crystal cell 10a used.

Further, in this embodiment, in order to average the luminance distribution, the direction away from the light source 26 (first direction).
This is dealt with by reducing the pitch of the flat portion 21, but the sum of the pitches of the flat portion 21 and the inclined portion 22 may be reduced by changing the angle of the inclined portion 22 instead of the pitch. . For example, the flat portion 21 is made small, and the angle α formed by the flat portion 21 and the inclined portion 22 is set to the light source 26.
The sum of the pitches of the flat portion 21 and the inclined portion 22 can be reduced by reducing the distance in the direction away from (first direction). Even in this case, since the incident light can be efficiently emitted to the inclined portion 22 in the direction (first direction) away from the light source 26, the luminance distribution can be averaged.

Furthermore, the reflective LC according to the present embodiment
D denotes the front light 2a in addition to the front light 20a having the above-described configuration and the reflective liquid crystal cell 10a having the above-described configuration.
0a and the reflective liquid crystal cell 10a, an antireflection film as a second light guide is arranged.

Explaining this antireflection film, in the reflection type LCD, as shown in FIG. 37, the interface (first emission surface) between the polarizing plate 18 disposed in the reflection type liquid crystal cell 10a and the light guide 24a. Then, the antireflection film 13 as the antireflection film is adhered.

As the antireflection film 13, an antireflection film (trade name: TAC-HC / AR) manufactured by Nitto Denko Corporation is used in this embodiment. The antireflection film 13 is a multilayer structure film having a four-layer structure. Specifically, using a triacetyl cellulose (TAC) film as a substrate layer, thereon, MgF ₂ layer as a first layer, CeF ₃ layer as the second layer, TiO ₂ layer as the third layer, fourth The antireflection film 13 has MgF ₂ layers formed as layers.

The TAC film has a refractive index n _t = 1.
At 51, the thickness is 100 μm. Also, the first layer M
The gF ₂ layer has a refractive index of _nm = 1.38 and a thickness of about 100 n.
m, the second CeF ₃ layer has a refractive index n _C = 2.30 and a thickness of about 120 nm, and the third TiO ₂ layer has a refractive index n _ti =
The thickness of 1.63 is about 120 nm, and the fourth MgF ₂ layer is
The refractive index n = 1.38 and the thickness is about 100 nm.
These first to fourth layers are sequentially formed on the TAC film of the base material layer by a vacuum deposition method.

Further, at the time of adhering to the front light 20a, a layer of an acrylic adhesive agent having a refractive index n ₁ substantially the same as the refractive index n _{2 of the} acrylic material used for the light guide 24a is used. Is forming. Therefore, the antireflection effect can be improved without substantially changing the light input / output conditions in the light guide 24a, and the unevenness of the luminance distribution and the occurrence of the rainbow color spectrum can be prevented.

The TAC film of the first layer is not essential for the structure of the antireflection film 13. For example, the second to fourth layers except the first layer are used as the light guide 24a. You may laminate directly. However, in this case, the manufacturing cost may increase slightly.

The antireflection film 13 of the above-mentioned multilayer structure film
Is λ / 4−λ for incident light of wavelength λ = 550 nm.
The configuration is a / 2-λ / 4-λ / 4 wave plate.
Therefore, the antireflection film 13 can act as the antireflection film 13 in a wide wavelength band.

In the light guide 24a described above, the light guide 24a
The inclined portion 22 formed on the surface (interface 23) of a is
It functions as a minute light source unit for the reflective liquid crystal cell 10a. Therefore, the reflective liquid crystal cell 10a is irradiated with light from the inclined portion 22, but the interface 28, which is a surface facing the interface between the light guide 24a and the reflective liquid crystal cell 10a, that is, the interface 23. At the inclined portion 2
About 4% of the light from 2 is reflected and becomes reflected light.

By the generation of this reflected light, a reflected image is formed from the interface 28 to the interface 23 side. for that reason,
This reflected image and the image on the inclined portion 22 interfere or diffract with each other, resulting in uneven brightness distribution and iridescent spectrum on the surface of the reflective LCD as viewed by an observer.

However, in the reflective LCD according to the present embodiment, the antireflection film (antireflection film 13) is provided between the reflective liquid crystal cell 10a and the front light 20a, that is, on the interface 28 side of the light guide 24a. ) Is arranged, it is possible to suppress the generation of reflected light generated by the incident light from the inclined portion 22 being reflected at the interface 28.

Therefore, it is possible to prevent interference or diffraction between the image on the inclined portion 22 acting as the minute light source portion and the reflected image reflected on the interface 28 side. for that reason,
It is possible to prevent the unevenness of the luminance distribution on the display observed on the observer side (the interface 23 side) and the occurrence of rainbow color spectrum.

Comparing the brightness distribution of the display in the reflective LCD of the present embodiment with and without the antireflection film 13, as shown in FIG. The graph C when the antireflection film 13 is arranged is more uniform and uniform in brightness distribution than the graph D when 13 is not arranged, and the brightness itself is also improved. Recognize.

The antireflection film 13 having the above structure
Since the commercially available one can be used as it is, it is possible to suppress an increase in the manufacturing cost of the front light 20a. Therefore, inexpensive front light 2
It is possible to obtain 0a and a reflective LCD having the same.

Further, the light guide 24a which is the first light guide.
Refractive index n of₂Refractive index n which is almost equal to ₁To the adhesive that has
Since the antireflection film 13 is adhered to the
Reflection without changing the input / output conditions of light inside the body 24a
The prevention effect can be improved.

The structure and material of the antireflection film 13 are not limited to those described above. For example, as the structure of the wave plate, λ /
The configuration may be 4-λ / 2-λ / 2-λ / 2-λ / 4. With such a structure of the wave plate, the antireflection effect can be obtained in a wider wavelength band. Further, it may be an antireflection film having a single layer structure of a λ / 4 wavelength plate. However, in this case, the wavelength band in which the antireflection effect is obtained may be narrowed.

As described above, the pitch between the flat portion 21 and the inclined portion 22 formed on the surface (interface 23) of the light guide 24a is increased in the direction away from the light source 26 (first direction). By making it small, the amount of reflected light reflected by the inclined portion 22 can be increased in the direction away from the light source as compared with the conventional case. Therefore, the luminance distribution at the interface 23 (first emission surface) of the light guide 24a can be averaged.

Further, the flat portion 21 and the inclined portion 2 formed at the interface 23 of the light guide 24a in the front light 20a.
2 is formed smaller than the pitch of the reflection type liquid crystal cell 10a, the moire fringes caused by the interference of light by the BM formed around the pixels 56 and the groove of the inclined portion 22. Occurrence can be suppressed. Therefore, it is possible to prevent the display quality of the reflective LCD from deteriorating.

Further, by providing an antireflection film (antireflection film 13) between the reflective liquid crystal cell 10a and the front light 20a, the interface 23 of the light guide 24a is provided.
It is possible to prevent the unevenness of the luminance distribution and the occurrence of iridescent spectrum in the. Therefore, it is possible to obtain a reflective liquid crystal LCD that is brighter and has a higher display quality.

In addition, by forming an uneven portion on the reflective electrode 17a in the reflective liquid crystal cell 10a, incident light is diffused without affecting the orientation of liquid crystal molecules and the cell thickness. Therefore, an image can be observed even when light is incident on the reflective liquid crystal cell 10a from a direction other than the regular reflection direction.

[Embodiment 12] The following description will discuss still another embodiment of the present invention with reference to FIGS. 49 and 50. It should be noted that configurations having the same functions as the configurations described in the above-described respective embodiments are denoted by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 49, the reflection type LCD of this embodiment has the same basic structure as that of the second embodiment, but it is provided between the reflection type liquid crystal cell 10 and the front light system 51. The difference is that an antireflection film (antireflection film) 13 which is a third light guide (optical means) is arranged.

The antireflection film 13 is the same as that used in the first embodiment. The description of the antireflection film 13, the reflective liquid crystal cell 10, and the front light system 51 will be omitted because they have been described in the second and eleventh embodiments.

In this embodiment, the antireflection film 13 includes the third light guiding member in addition to the light guiding member 24 which is the first light guiding member and the light guiding member 40 which is the second light guiding member. It functions as a body.

When the antireflection film 13 is not formed, the light from the inclined portion 22 formed on the interface 23 (first emission surface) of the first light guide 24 is the second light guide. About 4% is reflected by the bottom surface (second surface) 42 of 40 to become reflected light. Inclined portion 22 formed by this reflected light
Image and the inclined portion 22 of the light guide 24 interfere with each other, and as a result, the interface 28 of the light guide 24.
The unevenness of the luminance distribution occurs on the (second emission surface).

Therefore, the reflective LC according to the present embodiment
In D, the same antireflection film 13 as in Embodiment 11 is arranged between the bottom surface 42 of the second light guide 40 and the surface of the reflective liquid crystal cell 10 on the display surface side. The arrangement of the antireflection film 13 can effectively suppress the generation of the reflected light. Therefore, it is possible to realize a reflective LCD that suppresses unevenness in the luminance distribution at the interface 28 and can realize high-quality display.

The antireflection film 13 is used as a reflection type LCD.
Comparing the case of arranging with No. and the case of not arranging, as shown in FIGS. 50 (a) and (b), as compared with FIG.
FIG. 50A showing the luminance distribution in the case where the antireflection film 13 is arranged has a luminance peak pitch p that is substantially equal over the entire bottom surface 42 of the second light guide 40 and a luminance peak. The unevenness of the luminance distribution is reduced due to the gentle slope. Therefore, it can be seen that the state of the brightness distribution is improved. Note that the measurement conditions at this time have been described in Embodiment 2 above with reference to FIG.

The antireflection film 13 has a second
The antireflection film 13 is adhered with an adhesive having a refractive index n _{4 which} is substantially equal to the refractive index n ₃ of the light guide body 40. Therefore, the antireflection effect can be improved without substantially changing the input / output conditions of the light in the second light guide 40.

Further, the antireflection film 13 having the above structure.
As for the above, since a commercially available one can be used as it is, an increase in the manufacturing cost of the front light system 51 can be suppressed. Therefore, an inexpensive front light system 51 and a reflective LC including the same are provided.
D can be obtained.

[0229]

As described above, in the front illumination device according to the present invention, the second light emitting surface of the light guide body is inclined so that the light mainly from the light source is reflected toward the first light emitting surface. Portions and flat portions that mainly transmit reflected light from the object to be illuminated are alternately formed, and as the distance from the light source increases, the sum of the width of the flat portion and the width of the inclined portion gradually decreases. Configuration, or away from the light source,
This is a configuration in which the number of the inclined portions per unit area increases.

According to each of the above structures, the brightness on the surface of the object to be illuminated is improved as the position is farther from the light source. Usually, since the brightness tends to decrease as the position is farther from the light source, in any of the above configurations, the decrease in the brightness of the illuminated object due to the distance from the light source is offset, and the light from the light source is emitted at a high angle. It is possible to efficiently guide the entire object to be illuminated.
As a result, there is an effect that the luminance distribution on the surface of the illuminated object can be averaged.

Further, the reflection type liquid crystal display device according to the present invention has a structure in which the front illumination device having the above structure is arranged on the entire surface as described above.

Thus, when there is a sufficient amount of ambient light, such as outdoors during the day, the front illumination device is used in the off state, while when the amount of ambient light cannot be obtained, the front illumination device is used. Can be lit and used. As a result, there is an effect that it is possible to provide a reflective liquid crystal display device that can always realize bright and high-quality display regardless of the surrounding environment.

Alternatively, in the other reflective liquid crystal display device according to the present invention, as described above, the light from the light source is mainly directed to the second emission surface of the light guide. A front illuminating device in which inclined portions that reflect light from the object to be illuminated and flat portions that mainly transmit the reflected light from the object to be illuminated are alternately formed, and a reflecting plate is provided on the first emission surface of the front illuminating device. A reflective liquid crystal element, wherein the reflective liquid crystal element has a scanning line, and the scanning line pitch P ₁
The relation of the sum w ₃ of the pitch of the flat portion and the pitch of the inclined portion on the second emission surface of the front illumination device is w ₃ ≠
The configuration is P ₁ .

According to the above arrangement, the pitch of the inclined portion of the front lighting device and the pitch of the black matrix formed around the pixels of the reflective liquid crystal element are deviated from each other. As a result, since it is possible to suppress the generation of moire fringes due to the interference between the black matrix and the inclined portion, it is possible to improve the display quality of the obtained reflective liquid crystal display device.

[Brief description of drawings]

FIG. 1 is a sectional view showing a configuration of a reflective LCD according to an embodiment of the present invention.

FIG. 2 is a view showing a shape of a light guide of a front light included in the reflective LCD, and FIG. 2 (a) is a plan view of the light guide seen from above in a normal direction of a flat portion. (B) is
The side view of the light guide seen from the direction normal to the incident surface, FIG.
[FIG. 3] is a cross-sectional view of the light guide body taken along a cross section whose normal line is the longitudinal direction of the light source.

3 (a) to (c) are explanatory diagrams showing the behavior of light from a light source inside a light guide.

FIG. 4 is an explanatory diagram showing a behavior of light reflected by a reflective plate of a reflective LCD.

FIG. 5 is an explanatory diagram of a measurement system for measuring the light intensity of the front light.

FIG. 6 is a graph showing a measurement result of light intensity of the front light.

FIG. 7A is an explanatory diagram showing a relationship between light emitted from the light-emitting display and ambient light, and FIG.
FIG. 4 is an explanatory diagram showing a relationship between light emitted from the reflective LCD and ambient light.

FIG. 8 is a sectional view showing a configuration of a reflective LCD according to another embodiment of the present invention.

9A is a front light system included in the reflective LCD shown in FIG. 8, in which the distance from the inclined portion of the light guide to the surface serving as the emission surface of the front light system is uniform. A cross-sectional view showing that, FIG.
For comparison, in the front light included in the reflective LCD of the above-described embodiment, it is a cross-sectional view showing that the distance from the inclined portion to the surface serving as the emission surface of the front light is not uniform.

FIGS. 10A and 10B are explanatory views showing a measurement system for measuring the luminance distribution of the illumination light according to the configurations shown in FIGS. 9A and 9B, respectively.

11A and 11B are graphs showing measurement results of the luminance distribution of illumination light with the configurations shown in FIGS. 9A and 9B, respectively.

FIG. 12 is a cross-sectional view showing a configuration of a reflective LCD according to still another embodiment of the present invention.

13 is a schematic diagram showing a behavior of light in a front light system included in the reflective LCD shown in FIG.

14 is a graph showing measurement results of luminance distribution of illumination light of the front light system included in the reflective LCD shown in FIG.

FIG. 15 is an explanatory diagram showing the principle of image blurring or blurring in a reflective LCD according to still another embodiment of the present invention.

FIG. 16 is an enlarged cross-sectional view showing a part of an inclined portion of the light guide of the reflection type LCD, showing a configuration in which a metal reflection film is provided on the inclined portion.

FIGS. 17A to 17E are cross-sectional views showing a step of forming the metal reflection film.

FIG. 18 is a schematic diagram showing a behavior of light when the metal reflection film is not provided.

19 is a cross-sectional view showing a modified example of the configuration shown in FIG.

FIG. 20 is a cross-sectional view showing a configuration of a reflective LCD according to still another embodiment of the present invention.

FIG. 21 is a schematic diagram showing a behavior of light between a light guide and an optical compensation plate in the reflective LCD.

22 shows a structure of a reflective LCD as a modified example of the structure shown in FIG. 20, and FIG. 22 (a) is a sectional view of the reflective LCD, FIG. 22 (b) and FIG. 22 (c). FIG. 3 is a cross-sectional view showing a configuration example of an optical compensation plate of this reflective LCD.

FIG. 23 is a cross-sectional view showing a configuration of a touch panel included in a reflective LCD according to still another embodiment of the present invention.

FIG. 24 is a cross-sectional view of the touch panel and a plan view of reflective electrodes provided on the touch panel.

FIG. 25 is a plan view showing a configuration for detecting coordinates of a position pressed by a pen on the touch panel.

FIG. 26 is a cross-sectional view showing a state in which a part of the touch panel is pressed by a pen.

FIG. 27 is a cross-sectional view showing a configuration of a reflective LCD according to still another embodiment of the present invention.

28 is an explanatory diagram for explaining a condition for totally reflecting the light incident from the incident surface in the inclined portion in the light guide body of the reflective LCD shown in FIG. 27.

29 is a graph showing the light-collecting characteristics of the prism sheet included in the reflective LCD shown in FIG.

30 (a) and 30 (b) are explanatory views showing another configuration example applicable to the reflection type LCD shown in FIG. 27 for limiting the spread of incident light.

31 (a) to 31 (c) are cross-sectional views showing the behavior of light in the light guide body, together with the structure of the light guide body provided in a reflective LCD according to still another embodiment of the present invention. It is a figure.

FIG. 32 is a cross-sectional view showing a configuration of a reflective LCD as still another embodiment of the present invention.

33 is an explanatory diagram for explaining a condition of a tilt angle of an incident surface of the front light of the reflective LCD shown in FIG. 32.

FIG. 34 is a perspective view showing a configuration of a reflective LCD according to still another embodiment of the present invention.

FIG. 35 is a perspective view showing a usage example of a lighting device according to still another embodiment of the present invention.

FIG. 36 is a plan view showing an example of use of the lighting device shown in FIG. 35.

FIG. 37 is a cross-sectional view showing a configuration of a reflective LCD according to still another embodiment of the present invention.

38 shows the shape of the light guide body of the front light included in the reflective LCD shown in FIG. 37, and FIG.
Is a plan view of the light guide seen from above in the normal direction of the flat portion, (b) of the figure is a cross-sectional view of the light guide seen from the direction of the normal of the incident surface, and (c) of FIG. It is sectional drawing which cut | disconnected the optical body by the cross section which makes the longitudinal direction of the light source the normal.

39 is an explanatory diagram illustrating a configuration of a flat portion and an inclined portion in the light guide body shown in FIG. 38.

FIGS. 40 (a) and 40 (b) are explanatory views showing the behavior of the light from the light source in the light guide.

41 is a graph showing the relationship between the distance from the light source and the brightness in the front light included in the reflective LCD shown in FIG. 37.

42 is a graph showing the characteristics of the angle of emitted light in the front light included in the reflective LCD shown in FIG.

43 is a cross-sectional view showing the configuration of a reflective liquid crystal cell included in the reflective LCD shown in FIG. 37.

44A to 44E are process diagrams showing a method of forming a reflective electrode in the reflective liquid crystal cell shown in FIG. 43.

45 is a graph showing the reflectance angle dependence of the reflective electrode in the reflective liquid crystal cell shown in FIG. 43.

FIG. 46 is a cross-sectional view showing another example of the reflective liquid crystal cell shown in FIG. 43.

47. Pixels in the reflective liquid crystal cell shown in FIG. 43,
It is a top view showing composition of a scanning line and a signal line.

48 is a graph showing luminance and luminance distribution characteristics of emitted light in the front light included in the reflective LCD shown in FIG. 37.

FIG. 49 is a cross-sectional view showing the configuration of a reflective LCD according to still another embodiment of the invention.

50 (a) and 50 (b) are graphs showing measurement results of luminance distribution of illumination light in a front light and a conventional front light included in the reflective LCD shown in FIG. 49, respectively.

FIG. 51 is a cross-sectional view showing a schematic configuration of a conventional reflective LCD with auxiliary illumination and a behavior of light in the reflective LCD.

FIG. 52 is a cross-sectional view showing a behavior of light in the conventional reflective LCD.

[Explanation of symbols]

10 Liquid crystal cell (reflection type liquid crystal element) 12 Liquid crystal layer 13 Antireflection film (antireflection film, optical means) 17 Reflector 18 Polarizer 19 Insulating film 20 Front light (front lighting device) 21 Flat part 22 Inclined part 23 Interface (second emission surface) 24 Light Guide (First Light Guide) 25 Incident surface 26 light source 27 Reflector (Condensing means) 28 Interface (first emission surface) 45 Second light guide 64 Optical Compensation Plate (Compensation Means) 72 Transparent electrode (position detection means) 73 Reflective electrode (position detection means)

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takeshi Masuda             22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka             Inside the company (72) Inventor Takeshi Ebi             22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka             Inside the company F-term (reference) 2H091 FA02Y FA08X FA11X FA14X                       FA16Y FA16Z FA19X FA21X                       FA23X FA32X FA32Y FA34X                       FA35X FA35Y FA37X FA41X                       FA42X FA44X FA45X FB02                       FB07 FB08 FC02 FC10 FC17                       FC19 FC23 FC26 FD06 FD14                       GA02 HA06 HA08 HA09 JA01                       JA02 KA01 KA10 LA03 LA16                       LA17 LA18 LA21

Claims (7)

[Claims] 1. A light source and a light guide body arranged in front of an object to be illuminated, wherein the light guide body has an incident surface on which light from the light source enters.
A first emission surface that emits light toward the object to be illuminated and a second emission surface that faces the first emission surface and that emits reflected light from the object to be illuminated are provided. An inclined portion that mainly reflects the light from the light source toward the first emission surface and a flat portion that mainly transmits the reflected light from the object to be illuminated are alternately formed on the second emission surface. The front illumination device is characterized in that the sum of the width of the flat portion and the width of the inclined portion gradually decreases as the distance from the light source increases. 2. A light source and a light guide body arranged in front of an object to be illuminated, wherein the light guide body has an incident surface on which light from the light source is incident,
A first emission surface that emits light toward the object to be illuminated and a second emission surface that faces the first emission surface and that emits reflected light from the object to be illuminated are provided. An inclined portion that mainly reflects the light from the light source toward the first emission surface and a flat portion that mainly transmits the reflected light from the object to be illuminated are alternately formed on the second emission surface. The front lighting device is characterized in that the number of the inclined portions per unit area increases as the distance from the light source increases. 3. The front lighting device according to claim 1, wherein the incident surface is present on a side surface of the light guide. 4. The front illumination device according to claim 1, further comprising a light condensing unit that allows light from a light source to enter only the incident surface. 5. A reflection type liquid crystal display device comprising the front illumination device according to claim 1 arranged on the entire surface. 6. A light source and a light guide body arranged in front of an object to be illuminated, wherein the light guide body has an incident surface on which light from the light source enters.
A first emission surface that emits light toward the object to be illuminated and a second emission surface that faces the first emission surface and that emits reflected light from the object to be illuminated are provided. On the second emission surface, an inclined portion that mainly reflects the light from the light source toward the first emission surface and a flat portion that mainly transmits the reflected light from the object to be illuminated are alternately formed. And a reflection type liquid crystal element having a reflection plate on the first emission surface of the front illumination apparatus. The reflection type liquid crystal element includes a scanning line, and the pitch P of the scanning lines is provided. _The reflective liquid crystal display is characterized in that the relationship between ₁ and the sum w ₃ of the pitch of the flat portion and the pitch of the inclined portion on the second emission surface of the front illumination device is w ₃ ≠ P _1. apparatus. 7. The relationship between P ₁ and w ₃ is w ₃ > 2.
7. The reflective liquid crystal display device according to claim 6, wherein P ₁ or w ₃ <1 / 2P ₁ .