JP2003131228A - Liquid crystal illuminator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a light source device that emits light easily passing through the transmission axis of a polarizer attached to a liquid crystal display element. SOLUTION: This light source device (10) is constituted by attaching a light emission diode (12) to both side ends of a light guide rod (11) made of acrylic resins. Triangular grooves (100) are formed on the side face (11a) of the light guide rod, opposite to a light transmission plate, and the grooves are arranged at the same interval and are deeper as the grooves get far from the light emission diodes. When a refractive index is 1.49, the angle α of a first inclination surface (110) is set as α=32 deg.. Light reflected by the first inclination surface and made to emit vertically from the side surface (11b) of a light transmission plate is only an S wave, and light made to emit at other angles is an S wave in many cases. Even though the light is reflected at a prism array included in a prism (23) where mountains (23a) and valleys (23b) on the surface (22) of the light transmission plate respectively extend in an X direction and goes toward the liquid crystal display element through the polarizer, the light is inclined to go through the transmission axis of the polarizer because of many S waves.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal lighting device for illuminating a liquid crystal display element.

[0002]

2. Description of the Related Art Liquid crystal display devices are used in large quantities in many fields, but as is well known, liquid crystal display devices used in liquid crystal display devices do not have a function of emitting light by themselves, and therefore liquid crystal lighting devices. It is necessary to irradiate light with.
For example, as a liquid crystal lighting device, a light guide plate is disposed so as to face the surface of a liquid crystal display element, and a light emitting diode is provided in parallel with the end face of the side part of the light guide plate so as to face the incident end face of the side part of the light guide plate. The light source device attached to the end of the elongated light guide rod extending in the direction is provided, and the light emitted from the light emitting diode is reflected or refracted in the light guide rod, and the surface of the light guide rod on the light guide plate side. There is a device in which the light is emitted toward the incident surface of the light guide plate.

By the way, a liquid crystal display element is formed by sealing a liquid crystal material between transparent plates and attaching a polarizer to the liquid crystal display element. The polarizer has a transmission axis (an axis including a vibrating surface of light that can pass therethrough). ) Has. The transmission axis is usually not parallel to the light incident side end surface of the light guide plate (= one side end surface of the liquid crystal display device). However, in the conventional liquid crystal lighting device, light having a vibrating surface that matches the transmission axis of the polarizer attached to this liquid crystal display element is not guided, and the light emitted by the liquid crystal lighting device is not always fully utilized. There wasn't.

[0004]

In view of the above problems, the present invention provides a liquid crystal illuminating device that illuminates a liquid crystal display surface with light emitted from a light source device through a light guide plate, and the light emitted from the light source device is applied to a liquid crystal display element. The purpose is to allow the light to easily pass through the transmission axis of the attached polarizer.

[0005]

According to the invention of claim 1, the light emitted from the light source device is guided to the inside from the light incident side end surface of the light guide plate arranged outside one surface of the liquid crystal display element, A liquid crystal illuminating device for illuminating a liquid crystal display element by reflecting the liquid crystal display element of the light guide plate inside a distal first surface and causing the liquid crystal display element of the light guide plate to exit from a second surface proximal to the liquid crystal display element.
When Y and Z are three directions orthogonal to each other, the liquid crystal display element is formed by sandwiching a liquid crystal material between transparent plates and spreads in the XY directions, and a polarizer spreading in the XY directions is attached to the light guide plate side.
The polarizer has a transmission axis inclined from the Y direction in the XY plane, and the light guide plate has a light incident side end face elongated in the XZ direction, and a first face and a second face extended in the XY direction. A prism array is formed in the prism array, and the ridges and valleys of the prism array extend in the X direction, and the light source device faces the light incident side end face of the light guide plate and is long in the X direction in the Z direction. The side surface of the light guide plate that extends in a narrow and narrow manner, the side surface of the anti-light guide plate parallel to the side surface of the light guide plate, and the side surface of the light guide plate that connects the side surface of the anti-light guide plate to
Of a light guide rod having two surfaces that are elongated in the Y direction and elongated in the Y direction, and a light emitting diode is attached to at least one of the two end surfaces in the X direction. A plurality of first inclined surfaces extending toward the light guide plate side, and the first inclined surface has a side opposite to the light guide plate closer to the light emitting diode and a side closer to the light guide plate than the light emitting diode, and the side opposite to the light guide plate of the first inclined surface. Liquid crystal lighting device, wherein the angle α from the X direction is selected to be an angle at which light emitted perpendicularly from the side surface of the light guide plate toward the light source side end surface of the light guide plate is only S-wave light. Will be provided. In the liquid crystal lighting device configured as described above, the light perpendicular to the incident end surface of the light guide plate is only S-wave light.

According to a second aspect of the present invention, in the first aspect of the invention, the light guide rod is formed of a first substance, and the first substance has a refractive index of n ₁ and the first inclined surface serves as a boundary. When the refractive index of the second substance that is in contact with the guide rod and goes from the first substance to the first inclined face and through which the light transmitted through the first inclined face passes is n ₂ , tan (1-α) = n ₂ / n ₁ A liquid crystal lighting device is provided which is selected to satisfy

According to the invention of claim 3, in the invention of claim 2, the refractive index n ₁ of the first substance forming the light guide rod is 1.49, the second substance is air, and α is 32
A liquid crystal lighting device is provided, which is characterized in that

According to the invention of claim 4, in the invention of claim 1, the Y-direction anti-light guide plate side tip of the first inclined surface is on the anti-light guide plate side surface of the light guide rod, and the Y-direction light guide plate side. A liquid crystal lighting device is provided, wherein the tip is inside the light guide rod, and a second inclined surface reaching the side opposite to the light guide plate of the light guide rod is coupled to the tip on the light guide plate side.

According to the invention of claim 5, in the invention of claim 4, the depth from the side of the light guide plate opposite to the coupling portion of the first inclined surface and the second inclined surface increases as the distance from the light emitting diode increases. A liquid crystal lighting device is provided.

According to the invention of claim 6, in the invention of claim 1, the light emitting diode is attached to only one of the two ends of the light guide rod in the X direction, and the λ / 4 plate is attached to the other end. And a first inclined surface includes a pair of diode-side first inclined surfaces on the light emitting diode side and an anti-diode-side first inclined surface facing the diode-side first inclined surfaces. A liquid crystal lighting device is provided in which a second substance is interposed between the diode-side first inclined surface and the anti-diode-side first inclined surface.

According to the invention of claim 7, in the invention of claim 6, the Y-direction anti-light guide plate side tip of the first inclined surface is on the anti-light guide plate side surface of the light guide rod, and the Y-direction light guide plate side. There is provided a liquid crystal lighting device, wherein the tip is on the side surface of the light guide plate of the light guide rod.

According to the invention of claim 8, in the invention of claim 6, the second inclined surface is provided in addition to the first inclined surface, and the second inclined surface is provided.
The inclined surface includes a pair of a diode-side second inclined surface on the light emitting diode side and an anti-diode-side second inclined surface facing the diode-side second inclined surface, and the diode-side second inclined surface and the anti-diode-side second inclined surface. There is provided a liquid crystal lighting device, characterized in that a second substance is interposed between the inclined surfaces.

According to the invention of claim 9, in the invention of claim 8, the diode-side first inclined surface and the anti-diode-side second inclined surface, and the anti-diode-side first inclined surface and the diode-side second inclined surface. However, each is connected inside the light guide rod, and a liquid crystal lighting device is provided.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION A liquid crystal lighting device of the present invention will be described below with reference to the accompanying drawings. It should be noted that some of the drawings are exaggerated for the sake of explanation. FIG. 1 is a schematic diagram for explaining a liquid crystal lighting device according to a first embodiment of the present invention, in which X and Y directions are defined as shown in the figure, and the Z direction is a direction perpendicular to the plane of the figure. Define to.

Although the light source device 10 and the light guide plate 20 are shown in FIG. 1, the light source device 10 comprises a light guide rod 11 and light emitting diodes 12 attached to both ends of the light guide rod 11 in the X direction. The light guide rod 11 is made of a transparent resin such as acrylic and has a refractive index n ₁ of 1.49. Side 1 of the light guide plate 11 opposite to the light guide plate
As shown in the drawing, a triangular groove 100 is formed in 1a. The grooves 100 are formed at the same interval c, but the groove depth d is increased as the distance from the light emitting diode increases and becomes the deepest at the center. On the other hand, a prism array 22 including a large number of prisms 23 is formed on the surface of the light guide plate 20, and the peaks 23 a and the valleys 23 of the prism 23 are formed.
Each of b extends in the X direction.

In the case of this embodiment, the pitch P is 0.3 mm, and the groove depth d is set so as to satisfy the following equation. d = 0.015 × N ² + 0.5 × N + 15 (N = 1 to 1
83) = 0.015 x {166- (N-1)} ² +0.
5 × {166− (N−1)} + 15 (N = 84 to 16)
6) [Unit is μm] However, 166 grooves 100 are formed, and N is the groove 1
The number of the groove 100 at the left end is 1, and the number of the groove at the right end is 166. FIG. 2 is a diagram showing a change in the depth d of the groove 100. The groove depth d is 15.5 μ at both ends.
m and 159.8 μm at the center.

A group of grooves 100 shown to the left of the center,
The groups of grooves 100 shown on the right side of the center are similar to each other in size. The groove 100 has a first inclined surface 110 inclined inward at an angle α from a position near the light guide plate 11 on the side opposite to the light guide plate, and an angle β from a position far from the light guide diode on the side opposite the light guide plate 11.
In the present embodiment, the angle α of the first inclined surface 110 is 32 degrees, and the angle β of the second inclined surface 120 is 87 degrees. As shown in FIG. 3 in which the groove 100 is enlarged, the first inclined surface 110 and the second inclined surface 120 are connected by a bottom surface 130, and the bottom surface 13
The length of 0 is constant and is 0.005 mm.

In FIG. 4, the angle α of the first inclined surface 110 is set to 32.
FIG. 4 is a diagram for explaining the reason for setting the degree, in which the horizontal axis represents the angle α of the first inclined surface 110 and the vertical axis represents the side surface of the light guide plate of the light guide rod 11 with respect to the intensity of incident light including P waves and S waves. 11a
It shows the intensity of the P-wave light emitted from. The solid line shows the value of the light of the vertical component vertically emitted from the side surface 11a of the light guide plate of the light guide rod 11, and the broken line shows the value of the integral value of all the components. As can be seen from FIG. 4, when the angle α is 32 degrees, the maximum P
There are few waves and most S waves.

FIG. 5 is a view showing a path of light of a vertical component which is incident on the first inclined surface 110 inclined at 32 degrees as described above and vertically emerges from the side surface 11a of the light guide plate. At 110, the light is split into transmitted light and reflected light, and the reflected light becomes vertical component light. FIG. 5 is a diagram showing the ratio of the reflection and transmission of P waves and S waves incident on the first inclined surface 110 inclined at 32 degrees with respect to changes in the incident angle, and is shown by a thick solid line. Is the reflection rate of the S wave, the thick broken line is the transmission rate of the S wave, the thin solid line is the reflection rate of the P wave, and the thin broken line is the transmission rate of the P wave. From this figure, it can be seen that when the incident angle is 34 °, about 14% of S-wave is reflected and about 86% is transmitted, and almost all of P-wave is transmitted and almost all is transmitted.

FIG. 6 is a diagram showing the path of light incident on the first inclined surface 110 inclined at 32 degrees at an incident angle of 34 ° as described above. In this case, reflected light is emitted from the side surface 11a of the light guide plate. It becomes the light of the vertical component that emerges vertically.

FIG. 7 shows the first tilted at 32 degrees as described above.
FIG. 6 is a graph showing an extinction ratio (P wave / P wave + S wave) of reflected light which is incident on the inclined surface 110 and reflected, that is, a ratio between a thin solid line and a thick solid line in the graph of FIG. When the angle is 34 °, the extinction ratio is the smallest (zero),
Only S waves are emitted. The above value is the refractive index n ₁
Is the case of 1.49 as described above.

FIG. 8 is a diagram for explaining the path of light emitted from the light source device 10 including the light guide rod 12 constructed as described above until it reaches the liquid crystal display element 30, and is shown in an exploded view. However, in reality, each member is closely attached. The light emitted from the light emitting diode 12 is reflected inside the first inclined surface 110 of the light guide rod 11 as described above, goes toward the light guide plate side surface 11a, is emitted from the light guide plate side surface 11a, and is incident on the light guide plate 20. The light enters the light guide plate 20 from the surface 21. The light that is incident on the light guide plate 20 is only the S wave that is vertically incident, and the light that is obliquely incident is also a light that has many S waves.

The light incident on the light guide plate 20 is reflected by the inner surface of the prism 23 on the surface of the light guide plate 20,
The light is emitted from the surface of the liquid crystal display element side. The light emitted from the surface of the light guide plate 20 on the liquid crystal display element side reaches the liquid crystal display element 30 after passing through the polarizer 40. The transmission axis W of the polarizer 40 is neither parallel nor perpendicular to the X-axis and is inclined about 45 degrees with respect to the X-axis, but it is considered that light having many S waves when entering the light guide plate 20. When exiting the cage light guide plate 20, S
Since the light has many waves, it easily passes through the transmission axis W of the polarizer 40. Therefore, much light is emitted from the liquid crystal display element 3.
It reaches 0, and the brightness of the liquid crystal display element 30 is improved.

Next, the features of the second embodiment will be described. FIG. 9 shows the light guide rod 13 of the second embodiment.
FIG. 9 is a diagram showing the structure of FIG. 1, in which the light guide rod 13 is formed of two types of material substances, that is, the first substance portion 13A made of the first substance and the mesh in the diagram which are shown in white in the figure. It is formed of a second material portion 13B composed of the second material shown by being hung. The first substance portion 13A is the first
The second material portion 13B is made of an acrylic material having a refractive index of 1.49 similar to that of the first embodiment, but the second material portion 13B is an adhesive material having a lower refractive index.

On the other hand, the light emitting diode 12 is attached to the end portion of the light guide rod 13 in the X direction, but unlike the first embodiment, it is attached only to one end portion. A reflecting plate 15 is attached to the other end through the quarter-wave plate 14. In addition, the light guide rod 13
A reflection plate 18 is attached to the side surface 13a of the opposite light guide plate.

The first substance portion 13A has a first inclined surface 210 on the light emitting diode side and a first inclined surface 220 on the anti-light emitting diode side which are parallel to each other, and a light guide plate side surface and an anti-light guide plate side surface. The second material portion 13B fills a space between two adjacent first material portions 13A, and the light guide plate side surface and the anti-light guide plate side surface are flush with the light guide plate side surface and the anti-light guide plate side surface of the first material portion 13A. Has been The angle between the first inclined surface 210 on the light emitting diode side and the first inclined surface 220 on the anti-light emitting diode side from the X direction is about 45 degrees. While the angle of the first inclined surface is 32 in the first embodiment, such an angle is set because the refractive index n ₂ of the second substance portion 13B is equal to that of the first substance portion 13A. This is because it is close to the refractive index n ₁ .

From the light emitting diode 12 to the light guide rod 1
The light that has entered P. 3 contains P waves and S waves, but
The first surface 210 on the light emitting diode side of the member 13A is divided into reflected light and transmitted light, and the reflected light is mostly S waves. The transmitted light passes through the second member 13B and then enters the next first member 13A from the anti-light emitting diode side first inclined surface 220. At this time, the refractive index n ₂ of the second member 13B <the first member 13B.
Since the refractive index is n ₁ , the reflection does not occur. When exiting the first member 13A, the above-described operation is similarly performed.

The light which has reached the end face 13c on the side opposite to the light emitting diode of the light guide rod 13 by repeating the above-described action exits the end face 13c on the side opposite to the light emitting diode 13 and exits from the end face 13c.
After passing through, the light is reflected by the reflection plate 15, passes through the quarter-wave plate 14 again, enters the inside of the light guide rod 13 from the end surface 13c on the side opposite to the light emitting diode, and advances in the first member 13A toward the end surface on the side of the light emitting diode. To do. This light is 1/4 wave plate 1
Due to the action of 4, only the S wave is generated.

The light traveling toward the end surface 13d on the light emitting diode side is reflected by the first inclined surface 220 on the anti light emitting diode side and goes out of the light guide rod 13 from the side surface of the anti light guide plate, but is reflected by the reflection plate 16 and is again emitted. The light enters the guide rod 13. The light that has re-entered the light guide rod 13 reaches the anti-light emitting diode side first inclined surface 220, but since the incident angle to this surface (the angle from the normal to the surface) is small, it is almost transmitted, and then the It passes through the two members 13B and reaches the light emitting diode side first surface 210 of the adjacent first member 13A, but here it does not reflect due to the relationship of the above-mentioned refractive index, and from the side surface of the light guide plate of the adjacent first member 13A. The light is emitted toward the incident surface 21 of the light guide plate 20. The light that is re-incident from the side surface of the anti-light emitting diode into the light guide rod 13 is assumed to be only S waves, and the light that advances toward the incident surface 21 of the light guide plate 20 as described above is also only S waves.

In the second embodiment, light travels as described above, and almost only S-wave light enters the light guide plate 20. The light that enters the light guide plate 20 has the properties described in the first embodiment, and exits the light guide plate 20 and becomes light that easily passes through the transmission axis of the polarizer (see FIG. 7) 40. Therefore, the brightness of the liquid crystal display element 30 (see FIG. 7) is improved.

Next, the features of the third embodiment will be described. FIG. 10 shows an optical guide rod 1 according to the third embodiment.
7 is a diagram showing the structure of FIG. 7, in which the light guide rod 17 is made of two kinds of materials as in the second embodiment.
That is, the first substance portion 17 shown in white in the figure
The second material portion 17B is shown by A and is shaded in the figure.

However, the first material portion 17A and the second material portion 17B are not finely separated as in the second embodiment, but are a continuous second material portion 17B.
Therefore, the first substance portion 17A is only divided into two in the Y direction. That is, the second inclined surface 320 is formed continuously with the first inclined surface 310 on the center side (light guide plate side) of the first material portion 17A _{1 on} the side opposite to the light guide plate, and the first inclined surface 310 on the light guide plate side is formed.
A second inclined surface 420 is formed continuously with the first inclined surface 410 on the center side (anti-light guide plate side) of the substance portion 17A ₂ .

The first material portion 17A is made of acrylic having a refractive index of 1.49 similar to that of the first embodiment, but the second material portion 17B is an adhesive material having a lower refractive index. The angle of each inclined surface from the X direction is about 45 degrees. While the angle of the first inclined surface is 32 in the first embodiment, such an angle is set because the refractive index n ₂ of the second material portion 17B is the refractive index of the first material portion. Rate n ₁
Because it is close to.

From the light emitting diode 12 to the light guide rod 1
The light that has entered the inside of 7 includes the P wave and the S wave, but in the case of this embodiment, for example, as shown by the solid line, of the first material portion 17A ₂ on the light guide plate side. Second inclined surface 4
At 20, the reflected light is separated into the transmitted light, and the reflected light has many S waves. Transmitted light, then passes through the second member 17B, is incident from the first material portion 17A ₂ in the first inclined surface 320 of the light guide plate, when the refractive index _{n 2} <first second member 17B No reflection occurs because the refractive index of the member 17B is n ₁ . Then, the above-described operation is similarly performed again through the first substance portion 17A ₂ on the light guide plate side.

The light which has reached the end face on the side opposite to the light emitting diode side of the light guide rod 17 by repeating the above-described action exits the end face 17c on the side opposite to the light emitting diode, passes through the quarter wavelength plate 14, and is reflected by the reflection plate 15. Through the quarter-wave plate 14 again, from the end face 17c on the side opposite to the light emitting diode to the optical guide rod 17
The light enters the inside and travels through the first material portion 17A ₁ on the side opposite to the light guide plate toward the end face 17d on the light emitting diode side. This light is only S waves due to the action of the quarter-wave plate 14.

The light traveling toward the end surface 17d on the light emitting diode side is divided into reflected light and transmitted light at the second inclined surface 320 of the first material portion 17A ₁ on the side opposite to the light guide plate. Although the reflected light goes out of the light guide rod 17 from the side surface of the anti-light guide plate, the reflection plate 16
The light is reflected by and enters the light guide rod 17 again. The light that is re-incident in the light guide rod 17 reaches the second inclined surface 320 of the first material portion 17A ₂ on the light guide plate side, but this light is almost an S wave, and the second member 17B and the light guide plate side. First of
The light guide plate 20 is transmitted from the side surface of the light guide plate 20 through the substance portion 17A _2.
The light is emitted toward the incident surface 21 of.

On the other hand, in the case shown in this figure, the transmitted light is divided into reflected light and transmitted light by the first inclined surface 310 of the first material portion 17A ₁ on the side opposite to the light guide plate, and the reflected light is guided. The light guide plate side surface 17a is transmitted through the first material portion 17A ₂ on the light plate side.
The light is emitted from the light guide plate 20 toward the incident surface 21 of the light guide plate 20, and the transmitted light does the same at the second inclined surface 320 next to the first material portion 17A ₁ on the side opposite to the light guide plate.

In the third embodiment, light travels as described above, and almost only S-wave light enters the light guide plate 20. The light that enters the light guide plate 20 has the properties described in the first embodiment, and exits the light guide plate 20 and becomes light that easily passes through the transmission axis of the polarizer (see FIG. 7) 40. Therefore, the brightness of the liquid crystal display element 30 (see FIG. 7) is improved.

[0039]

According to the invention described in each claim, the light emitted from the light source device is guided to the inside from the end surface on the light incident side of the light guide plate arranged outside one surface of the liquid crystal display element, and the liquid crystal of the light guide plate is guided. A liquid crystal illuminating device for illuminating a liquid crystal display element by reflecting the light inside the first surface distal to the display element and causing the liquid crystal display element of the light guide plate to exit from the second surface proximal to the liquid crystal display element. When the three directions are orthogonal to each other, the liquid crystal display element is formed by sandwiching a liquid crystal material between transparent plates and spreads in the XY directions.
Is provided with a polarizer that extends in the direction, the polarizer has a transmission axis that is inclined from the Y direction in the XY plane, and the light guide plate has an end surface on the light incident side that is elongated in the XZ direction and has a first surface and a second surface. Is XY
The prism array is formed on the first surface, and the ridges and valleys of the prism array extend in the X direction, and the light source device faces the light incident side end surface of the light guide plate. The side surface of the light guide plate that extends in a slender shape so as to be long in the X direction and short in the Z direction, the side surface of the anti-light guide plate parallel to the side surface of the light guide plate, and the side surface of the light guide plate and the side surface of the anti-light guide plate are connected to each other so that they are long in the X direction and short in the Y direction A light guide rod having two surfaces extending in a slender shape, and a light emitting diode attached to at least one of the two end faces in the X direction, and the light guide rod extends from the side opposite to the light guide plate toward the light guide plate. The first inclined surface has a plurality of first inclined surfaces, the side opposite to the light guide plate is closer to the light emitting diode, and the side closer to the light guide plate is farther from the light emitting diode, and the angle α of the first inclined surface from the side opposite to the light guide plate is X. From the side of the light guide plate to the light source side end face of the light guide plate It is selected at an angle of only light of S-wave light emitted vertically me. In the liquid crystal lighting device configured as described above, the light perpendicular to the incident end surface of the light guide plate is only S-wave light, and the non-vertical light also has many S-waves.
After passing through the light guide plate, when passing through the polarizer disposed in front of the liquid crystal display element, a large amount of light is aligned with the transmission axis of the polarizer, and the brightness of the liquid crystal display element is improved.

[Brief description of drawings]

FIG. 1 is a top view of a first embodiment.

FIG. 2 is a diagram showing a change in groove depth of the light guide rod according to the first embodiment.

FIG. 3 is an enlarged view of the light guide rod of the first embodiment.

FIG. 4 is a diagram showing a relationship between an angle of an inclined surface of the light guide rod on the light emitting diode side of the first embodiment and an extinction ratio.

FIG. 5 is a diagram showing a reflection rate and a transmission rate of S waves in incident light, and a reflection rate and a transmission rate of P waves with respect to a change in an incident angle.

FIG. 6 is a diagram showing a typical path of light in the light guide rod according to the first embodiment.

FIG. 7 is a diagram showing a relationship between an incident angle of light striking an inclined surface of the light guide rod on the light emitting diode side of the first embodiment and an extinction ratio.

FIG. 8 is a diagram illustrating light traveling in a liquid crystal display device including the liquid crystal lighting device according to the first embodiment.

FIG. 9 is a top view of the second embodiment.

FIG. 10 is a top view of the third embodiment.

[Explanation of symbols]

Reference numeral 10 ... Light source 11 ... Optical guide rod 12 ... Light emitting diode 13 ... Optical guide rod 13A ... First material portion 13B ... Second material portion 14 ... Quarter wave plate 15 ... Reflector 16 ... Reflector 17 ... Optical guide rod 17A ₁ ... 1st substance part 17A (on the side opposite to a light guide plate) ₂ ... 1st substance part 17B (on the side of a light guide plate) 2nd substance part 20 ... Light guide plate 23 ... Prism 23a ... Peak 23b ... Valley 30 ... Liquid crystal display element 40 ... Polarizer 100 ... Groove 110 ... First slanted surface 120 ... Second slanted surface 210 ... Light emitting diode side first slanted surface 220 ... Anti light emitting diode side first slanted surface 310. ) First inclined surface 320 ... (Second light-guide plate side first material portion) Second inclined surface 410 ... (Light-guide plate side first material portion) First inclined surface 420 ... (Light-guide plate side first material portion) Second inclined surface

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G09F 9/00 G09F 9/00 336J H01L 33/00 H01L 33/00 M // F21Y 101: 02 F21Y 101: 02 F term (reference) 2H038 AA52 AA55 BA06 2H091 FA11X FA21Z FA23Z FA45Z LA17 LA18 5F041 AA14 DC07 EE23 EE25 FF11 5G435 AA03 BB12 BB15 BB16 EE22 EE27 FF02 FF08 FF12 GG23 GG26 HH02

Claims (9)

[Claims] 1. A first surface of the light guide plate distal to the liquid crystal display element, which guides light emitted from the light source device to the inside from an end surface of the light guide plate disposed outside one surface of the liquid crystal display element. A liquid crystal illuminating device for illuminating a liquid crystal display element by reflecting the light inside a liquid crystal display element of a light guide plate from a second surface proximal to the liquid crystal display element, wherein X, Y and Z are three orthogonal directions, The liquid crystal display element is formed by sandwiching a liquid crystal material between transparent plates.
A polarizer that extends in the Y direction and extends in the XY direction is attached to the light guide plate side, and the polarizer has a transmission axis that is inclined from the Y direction in the XY plane, and the light guide plate has a light incident side end face in the XZ direction. The first surface and the second surface spread in the XY directions, a prism array is formed on the first surface, and the ridges and valleys of the prism array extend in the X direction. The light source device includes a light guide plate side surface that faces the light incident side end surface of the light guide plate and extends slenderly so as to be long in the X direction and short in the Z direction, an anti-light guide plate side surface parallel to the light guide plate side surface, a light guide plate side surface, and an anti-light guide plate. A light guide rod having two surfaces extending in a slender shape so as to be long in the X direction and short in the Y direction by connecting to a side surface is formed by attaching a light emitting diode to at least one of the two end surfaces in the X direction. Extends from the opposite light guide plate side toward the light guide plate side A number of first inclined surfaces, and the first inclined surface has a light guide plate side closer to the light emitting diode and a light guide plate side farther from the light emitting diode, and an angle α of the first inclined surface from the opposite light guide plate side from the X direction is A liquid crystal lighting device, wherein the light vertically emitted from the side surface of the light guide plate toward the light source side end surface of the light guide plate is selected to have an angle of only S-wave light. 2. The light guide rod is formed of a first material,
The refractive index of the first substance is n ₁ , the refraction of the second substance that is in contact with the light guide rod with the first inclined surface as a boundary, goes from the first substance to the first inclined face, and through which the light transmitted through the first inclined face passes. The liquid crystal lighting device according to claim 1, wherein tan (1−α) = n ₂ / n ₁ is selected so that the ratio is n ₂ . 3. The refractive index n ₁ of the first substance forming the light guide rod is 1.49, the second substance is air, and α is set to 32 degrees. 2. The liquid crystal lighting device according to item 2. 4. The Y-direction anti-light guide plate side tip of the first inclined surface is on the anti-light guide plate side surface of the light guide rod, and the Y-direction light guide plate side tip is inside the light guide rod and is on the light guide plate side. The liquid crystal lighting device according to claim 1, wherein a second inclined surface reaching an opposite side of the light guide plate of the light guide rod is coupled to a tip of the liquid crystal lighting device. 5. The depth from the side opposite to the light guide plate of the coupling portion of the first inclined surface and the second inclined surface is set to increase as the distance from the light emitting diode increases. The described liquid crystal lighting device. 6. The light emitting diode is attached to only one of two ends of the light guide rod in the X direction, and a reflector is attached to the other end of the light guide rod via a λ / 4 plate.
The inclined surface includes a pair of a diode-side first inclined surface on the light emitting diode side and an anti-diode-side first inclined surface facing the diode-side first inclined surface. The diode-side first inclined surface and the anti-diode-side first inclined surface The liquid crystal lighting device according to claim 1, wherein the second substance is interposed between the inclined surfaces. 7. The Y-direction anti-light guide plate side end of the first inclined surface is on the anti-light guide plate side face of the light guide rod, and the Y direction light guide plate side end is on the light guide plate side face of the light guide rod. The liquid crystal lighting device according to claim 6, wherein the liquid crystal lighting device is a liquid crystal lighting device. 8. A second inclined surface is provided in addition to the first inclined surface,
The second inclined surface includes a pair of diode-side second inclined surfaces on the light emitting diode side and an anti-diode-side second inclined surface facing the diode-side second inclined surfaces, and the diode-side second inclined surface and the anti-diode side. The liquid crystal lighting device according to claim 6, wherein a second substance is interposed between the second inclined surfaces. 9. A diode-side first inclined surface and an anti-diode-side second inclined surface, and an anti-diode-side first inclined surface and a diode-side second inclined surface are connected inside an optical guide rod, respectively. The liquid crystal lighting device according to claim 8, wherein the liquid crystal lighting device is a liquid crystal lighting device.