JP2006140078A - Lighting device, electro-optical device, and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electro-optical device capable of effectively utilizing reflection light reflected from a light guide plate for display. <P>SOLUTION: The electro-optical device comprises a light source 5 for generating light, a light guide body 6 which introduces the light generated by the light source 5 from a light incident face 6a and emits from a light outgoing face 6b, a light diffusion pattern 9 which is installed partially on the light outgoing face 6b, and a light reflection pattern 8 which is installed on the face opposite to the light outgoing face 6b of the light guide body 6. The light diffusion pattern 9 is installed on the light outgoing face 6b at a location corresponding to the emitting location of the light emitted from the light outgoing face 6b after reflected by the light reflection pattern 8. The light emitted from the light guide body 6 is diffused at the portion where the diffusion pattern 9 is located, and is taken out in high luminance at the portion where the diffusion pattern 9 is not located without diffusing. Thereby, surface light having high luminance while being uniform can be obtained. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electro-optical device such as a liquid crystal display device. The present invention also relates to an illumination device used for an electro-optical device or the like. The present invention also relates to an electronic apparatus using an electro-optical device.

  Currently, electro-optical devices are widely used in various electronic devices such as mobile phones and portable information terminals. These electro-optical devices are used, for example, as a display unit for visually displaying various types of information related to electronic devices. In this electro-optical device, for example, a device using liquid crystal as an electro-optical material, that is, a liquid crystal display device is known.

  The liquid crystal display device has a liquid crystal panel as an electro-optical panel. This liquid crystal panel generally has a structure in which a liquid crystal layer is interposed between a pair of substrates each having an electrode. In this liquid crystal display device, the orientation of liquid crystal molecules in the liquid crystal layer is controlled for each pixel by supplying light to the liquid crystal layer and controlling the voltage applied to the liquid crystal layer for each pixel. The light supplied to the liquid crystal layer is modulated according to the alignment state of the liquid crystal molecules, and by supplying the modulated light to the liquid crystal side surface of the polarizing plate, letters, numbers, figures, etc. are formed on the observation side surface of the polarizing plate. Is displayed.

  An illumination device may be used to supply light to the liquid crystal layer as described above. This illuminating device includes, for example, a light source that emits light and a light guide that emits light from the light source as planar light from a light emitting surface. As a daylighting method using such an illuminating device, a transmissive type and a transflective type are known. In transmissive and transflective liquid crystal panels, light can be supplied to the liquid crystal layer by disposing a lighting device as a so-called backlight on the opposite side of the display surface of the liquid crystal panel. In the transflective type, it is possible to selectively use light from the lighting device and external light such as sunlight or room light. In this case, the external light is reflected by the reflective layer inside the liquid crystal panel and supplied to the liquid crystal layer.

  Conventionally, the illumination device as described above has a structure in which a light reflection pattern is provided on the surface opposite to the light emission surface of the light guide, and a light diffusion layer is provided opposite to the light emission surface ( For example, see Patent Document 1).

Japanese Patent No. 2780046 (pages 2 and 3, FIG. 1)

  According to the illuminating device disclosed in Patent Document 1, by providing the diffusion pattern on the light emitting surface of the light guide, the light reflected by the light reflecting surface can be diffused by the diffusion pattern. Can emit planar light with uniform brightness. However, in the conventional lighting device, the light diffusion layer is provided over the entire surface of the light emitting surface. For this reason, there is a problem that the light reflected by the light guide cannot be effectively used as the light for illuminating the illumination object.

  The present invention has been made in view of the above problems, and an object thereof is to make it possible to effectively use reflected light reflected by a light guide plate for display.

  The illumination device according to the present invention is provided in part on the light emitting surface, a light source that generates light, a light guide that introduces light generated from the light source from the light incident surface and emits the light from the light emitting surface, and And a light reflection pattern provided on a surface opposite to the light exit surface of the light guide, and the light diffusion pattern is reflected by the light reflection pattern from the light exit surface. It is provided on the light emission surface at a position corresponding to the emission position of the emitted light.

  According to this illuminating device, since the light diffusing pattern is provided on the light emitting surface of the light guide, the light emitted from the inside of the light guide can be diffused at an appropriate place to emit light with uniform luminance from the light emitting surface. . Further, the light diffusion pattern is partially provided on the light emitting surface at a position corresponding to the emission position of the light reflected from the light reflecting pattern and emitted from the light emitting surface, and thus no light diffusion pattern is provided. Light that is not diffused can be emitted from the partial light exit surface. Since the light in the non-diffused state maintains a high intensity, the intensity of the light emitted from the entire light exit surface of the light guide is higher than that in the case where the light diffusion pattern is provided over the entire light exit surface. Become. Thereby, the illuminating device which concerns on this invention can illuminate an illumination target object brightly with the light which comes out of a light guide.

  Next, in the illuminating device according to the present invention, light in a region corresponding to an appropriate angle within a range of a half-value angle or more and a 1/10 value-angle or less in a viewing angle characteristic of light emitted from the light emission surface is emitted. It is desirable to provide the light diffusion pattern at a position where it can be diffused.

  Here, the viewing angle characteristic regarding the illumination device will be described with reference to a simple drawing. The light guide of the illuminating device of the present invention has a light reflection pattern 108 on the surface opposite to the light exit surface 106b, for example, as indicated by reference numeral 106 in FIG. In FIG. 6, the light reflecting pattern 108 is formed as a depression or groove, that is, a recess. When a light source 105, for example, an LED, disposed facing the light incident surface 106a of the light guide 106 emits light, the light is introduced into the light guide 106 through the light incident surface 106a, and part of the light is light. The light is reflected by the reflection pattern 108 and emitted from the light emission surface 106b to the outside.

  At this time, with respect to the linear direction (A-A ′ direction in FIG. 6) that crosses the light exit surface 106 b, the exit light is considered to exhibit viewing angle characteristics as indicated by the symbol Q with respect to its intensity. In the viewing angle characteristic Q, the vertical axis indicates the light intensity, and the horizontal axis indicates the light emission angle. This viewing angle characteristic is not simply provided by a single light reflection pattern 108, but a plurality of light reflection patterns 108 that affect the AA ′ direction, light that has propagated through the light guide 106, and the like. It is brought about by the combination of

In this viewing angle characteristic Q, the angle at the position P1 at which the light intensity is ½ of the light intensity I0 in the normal direction is a half-value angle. The angle of the position P2 at which the light intensity becomes 1/10 of the light intensity I0 in the normal direction is a 1/10 value angle. In FIG. 6, the half-value angle is
(A) α1 (+) which is an angle on the plus side from the normal direction N (angle 0 °),
(B) α1 (−) which is an angle on the negative side from the normal direction N, or (c) 1/2 of the angular width of the full width ((α1 (+) + α1 (−)) / 2
Can be represented by either In the following description, these half-value angles (a) to (c) may be collectively referred to as “α1”.

The 1/10 value angle is
(A) α2 (+) which is an angle on the plus side from the normal direction N,
(B) α2 (−) which is an angle on the minus side from the normal direction N, or (c) 1/2 of the angular width of the full width ((α2 (+) + α2 (−)) / 2
Can be represented by either In the following description, the 1/10 value angles of (a) to (c) may be collectively referred to as “α2”.

  In the electro-optical device according to the present invention having the above-described configuration, an appropriate angle α within the range of the half-value angle α1 or more and the 1/10 value angle α2 or less in the viewing angle characteristic Q is considered, and the region corresponding to the angle α The light diffusion pattern 109 is provided at a position where light (that is, the light indicated by the oblique lines) can be diffused, and the light diffusion pattern 109 is not provided in other regions.

Next, in the illuminating device according to the present invention, an appropriate angle within a range of a half-value angle or more and a 1/10 value-angle or less in a viewing angle characteristic of light emitted from the light exit surface is defined as α, and the light guide When the refractive index inside is n1, and the outside refractive index of the light guide is n2,
n1 · sin α = n2 · sin β (1)
It is desirable to provide the light diffusion pattern at a position that blocks the light reflected from the light reflection pattern within the range of the angle β determined by. The above equation (1) is an equation based on the so-called Snell's law in the field of optics.

  In the embodiment of the present invention, for example, in FIG. 3, the emission angle α of light that needs to be diffused out of the emitted light on the light emitting surface 6 b of the light guide 6 is defined as a viewing angle characteristic (for example, symbol Q in FIG. 6). From the determined angle α, the emission angle β inside the light guide 6 is obtained according to the above equation (1), and the angle β with respect to the light reflection pattern 8 provided on the light reflection surface of the light guide 6 is determined. The light diffusion pattern 9 is provided on the light exit surface 6b within the range. By adopting this configuration, it is possible to reliably diffuse light that needs to be diffused, and to obtain sufficient light intensity without meaninglessly diffusing light that should maintain its intensity.

  Next, in the illuminating device according to the present invention, from the light reflection pattern within the range of the plurality of angles β obtained based on viewing angle characteristics along a plurality of different linear directions crossing the plane of the light emitting surface. It is desirable to provide the light diffusion pattern at a position that blocks each light reflected in different directions.

  In the description using FIG. 6 above, the viewing angle characteristic Q along one direction crossing the light emitting surface 106b of the light guide 106 is simulated, and the angle α that requires diffusion based on the viewing angle characteristic Q is simulated. The angle β on the reflecting surface is obtained by calculation based on the angle α, and the position where the light diffusion pattern 109 is formed on the light emitting surface is determined by the angle β.

  Here, the viewing angle characteristic Q does not exist in only one direction in the light exit surface 106b but exists in innumerable directions in the light exit surface 106b. If the direction to be adopted is different, the viewing angle characteristic Q changes variously. Therefore, the light diffusion pattern having a shape suitable for the purpose may not be formed strictly by simply determining the formation position of the light diffusion pattern based on only one viewing angle characteristic Q. On the other hand, if the shape and the formation position of the light diffusion pattern are determined based on a plurality of viewing angle characteristics relating to one light exit surface, both the desired diffusion effect and the desired light intensity can be obtained.

  Next, in the illuminating device according to the present invention, it is desirable that the surface of the light guide opposite to the light exit surface is composed of the light reflection pattern and a mirror surface. In this way, high intensity reflected light can be obtained from the light guide.

  Next, in the electro-optical device according to the aspect of the invention, it is preferable that a light reflection layer is provided to face the surface of the light guide opposite to the light emitting surface. In this way, the light from the light source can be reflected by other than the light reflection pattern. Further, external light such as sunlight or room light can be reflected by the light reflection layer. These lights are emitted to the outside of the light guide without being diffused from the light emission surface of the portion where the light diffusion pattern is not provided. Thereby, the light reflected by the light guide can be used effectively. Further, since external light can be used in addition to the light from the light source, it can be expected to improve the display brightness.

  Next, in the illumination device according to the present invention, it is desirable to provide a reflective polarizer so as to face the light emitting surface. A reflective polarizer is an optical element that has the property of allowing specific polarized light to pass and reflecting other polarized light. The lighting device of the present invention can be configured without necessarily using a reflective polarizer, but if a reflective polarizer is not used, a part of the light emitted from the light exit surface is wasted by a polarizing plate or the like. There is a fear. On the other hand, if a reflective polarizer is provided facing the light exit surface, the light that has been wasted until then can be reused as recycled light, and as a result, the light can be used very effectively. become.

  Next, an electro-optical device according to the present invention includes the illumination device having the above-described configuration and an electro-optical panel that receives light from the illumination device and performs display, and a light emission surface of the light guide is It is provided facing the electro-optical panel. The electro-optical panel is a panel structure that changes an optical output state by controlling electrical input conditions. For example, a liquid crystal panel in a liquid crystal display device can be considered. According to the electro-optical device according to the present invention, the electro-optical panel can perform display using the planar light emitted from the light emitting surface of the light guide. Since the light guide described above can emit light with uniform luminance by efficiently using light, display with uniform luminance can be performed even in the electro-optical panel.

  Next, an electro-optical device according to the present invention includes a lighting device and an electro-optical panel that receives light from the lighting device and performs display. The illumination device includes a light source that generates light, a light guide that introduces light generated from the light source from a light incident surface and emits the light from the light emission surface, and a light guide surface that is partially provided on the light emission surface. A light diffusion pattern; and a light reflection pattern provided on a surface of the light guide opposite to the light emitting surface. And in this illuminating device, the said light-diffusion pattern is provided on the said light-projection surface of the position corresponding to the radiation | emission position of the light reflected from the said light reflection pattern and radiate | emitted from the said light-projection surface.

  According to this electro-optical device, since the light diffusing pattern is provided on the light emitting surface of the light guide, the light emitted from the inside of the light guide is diffused at an appropriate place, so that light of uniform brightness is emitted from the light emitting surface. It can be emitted. Further, the light diffusion pattern is partially provided on the light emitting surface at a position corresponding to the emission position of the light reflected from the light reflecting pattern and emitted from the light emitting surface, and thus no light diffusion pattern is provided. Light that is not diffused can be emitted from the partial light exit surface. Since the light in the non-diffused state maintains a high intensity, the intensity of the light emitted from the entire light exit surface of the light guide is higher than that in the case where the light diffusion pattern is provided over the entire light exit surface. Become. Thereby, the illuminating device which concerns on this invention can supply light with uniform and high brightness | luminance to the electro-optical panel which is an illumination target object with the light which comes out of a light guide. As a result, uniform and high luminance display can be performed by the electro-optical panel.

  Next, an electronic apparatus according to the present invention includes the electro-optical device having the above-described configuration. As such an electronic device, a mobile phone, a portable information terminal, an IC recorder, a personal computer, and other various electronic devices can be considered. According to the electro-optical device according to the present invention, it is possible to perform display with uniform luminance by using light efficiently. Therefore, the electronic device of the present invention using the electro-optical device is also related to the electronic device. The display can be displayed with uniform brightness.

(First embodiment of illumination device and electro-optical device)
Hereinafter, a case where the present invention is applied to a liquid crystal display device which is an example of an electro-optical device will be described as an example. In addition, embodiment described below is an example of this invention, Comprising: This invention is not limited. In the following description, reference will be made to the drawings as necessary. In this drawing, in order to clearly show important constituent elements among the structure composed of a plurality of constituent elements, the relative dimensions different from actual ones are shown. May be shown.

  FIG. 1 shows an embodiment of a liquid crystal display device which is one of electro-optical devices according to the present invention in an exploded state. FIG. 2 shows a cross-sectional structure of the liquid crystal display device according to the line BB in FIG. FIG. 3 is an enlarged view of a portion indicated by an arrow D in FIG. In FIG. 1, the liquid crystal display device 1 includes a liquid crystal panel 2 as an electro-optical panel, a driving IC 3 mounted on the liquid crystal panel 2, and an illumination device 4. The liquid crystal display device 1 listed here is an active matrix type using a TFD (Thin Film Diode) element which is a two-terminal nonlinear element as a switching element, and is a transmissive liquid crystal display device. In the liquid crystal display device 1, the side on which the arrow A is drawn is the observation side.

  The illuminating device 4 includes an LED (Light Emitting Diode) 5 as a light source and a light guide 6 formed of a translucent resin such as an acrylic resin. The light guide 6 is formed in a rectangular or square flat plate shape. A straight chamfer is applied to one corner of the light guide 6, and the LED 5 is provided to face the chamfer. The light generated from the LED 5 is introduced into the light guide 6 through the chamfered portion that is the light incident surface 6a, and is emitted to the outside from the light emitting surface 6b. The illumination device 4 is disposed on the back side of the liquid crystal panel 2 when viewed from the observation direction indicated by the arrow A, and functions as a backlight that illuminates the liquid crystal panel 2 from the back side.

  The surface of the light guide 6 on the side opposite to the observation side is configured as a mirror surface, and a plurality of light reflection patterns 8 are individually formed in a dot shape on the surface. The light reflecting layer 7 is provided on the surface on which the plurality of light reflecting patterns 8 are provided. The light reflecting layer 7 can be formed by adhering a light reflecting sheet or applying or vapor-depositing a light reflecting material. The plurality of light reflection patterns 8 are formed side by side in a circular arc shape, an elliptical arc shape, a long circular arc shape, or other curved shapes around the LED 5. The plurality of light reflection patterns 8 can also be formed side by side in a straight line. For example, as shown in FIG. 2, each of the light reflection patterns 8 is formed as a depression, that is, a recess having a triangular cross section. These light reflecting patterns 8 can reflect the light emitted from the LEDs 5 toward the light emitting surface 6b of the light guide 6 as indicated by an arrow Lr.

  A plurality of light diffusion patterns 9 are partially formed in a dot shape on the light exit surface 6 b of the light guide 6. These light diffusion patterns 9 can diffuse the light Lr reflected by the light reflection pattern 8 as indicated by an arrow Ld. Then, the diffused light Ld travels from the light exit surface 6b toward the liquid crystal panel 2. These light diffusion patterns 9 are not provided in the entire area of the light exit surface 6b, but are formed only at positions corresponding to positions where the light Lr reflected by the light reflection pattern 8 exits from the light exit surface 6b. That is, the light diffusion pattern 9 is provided for each of the individual light reflection patterns 8. Details of the positional relationship between the light reflection pattern 8 and the light diffusion pattern 9 will be described later.

  Returning to FIG. 1, the liquid crystal panel 2 is formed by bonding the element substrate 11 and the color filter substrate 12 together with a sealing material 13 having a square or rectangular frame shape. As shown in FIG. 2, a gap, so-called cell gap G, is formed between the element substrate 11 and the color filter substrate 12, and liquid crystal as an electro-optical material is sealed in the cell gap G, and the liquid crystal layer 14. Is formed. As the liquid crystal, for example, a TN (Twisted Nematic) liquid crystal can be used. The cell gap G is maintained at a constant interval by the spherical spacer 15. The electro-optical material is a material whose optical characteristics change according to changes in electrical conditions.

  The element substrate 11 has a first substrate 16a having translucency, and a phase difference plate 17a is attached to the outer surface of the first translucent substrate 16a by sticking or the like, and further thereon. A polarizing plate 18a is attached by sticking or the like. On the other hand, the color filter substrate 12 has a second substrate 16b having translucency, and a phase difference plate 17b is attached to the outer surface of the second translucent substrate 16b by adhesion or the like. A polarizing plate 18b is mounted thereon by sticking or the like. The first light transmissive substrate 16a and the second light transmissive substrate 16b are formed of glass, plastic, or the like. Further, optical sheets other than the retardation plate and the polarizing plate can be provided on the outer surfaces of these substrates 16a and 16b as required.

  On the inner surface of the first translucent substrate 16a, that is, the liquid crystal side surface, for example, a line wiring 21 functioning as a data line, a TFD element 22 as a non-linear resistance element or a switching element, a dot electrode 23, an alignment A film 24a is formed. The dot electrode 23 is formed in a dot shape with a metal oxide such as ITO (Indium Tin Oxide). The alignment film 24a is made of polyimide, for example, and a rubbing process is performed on the surface thereof. By this rubbing treatment, the initial alignment of liquid crystal molecules in the vicinity of the element substrate 11 is determined.

  A plurality of straight line wirings 21 are provided on the element substrate 11. Each of the line wirings 21 extends in the left-right direction in FIG. 2, and the plurality of line wirings 21 are arranged in parallel with each other at a predetermined interval in the direction perpendicular to the paper surface of FIG. As a whole, they are provided in a stripe shape when viewed from the direction of arrow A. The plurality of TFD elements 22 are connected along the individual line wirings 21 at appropriate intervals, and the dot electrodes 23 a are connected to the TFD elements 22.

  In FIG. 1, the element substrate 11 has a projecting portion 19 projecting outside the color filter substrate 12, and the driving IC 3 uses an ACF (Anisotropic Conductive Film) 25 on the projecting portion 19. It is implemented by the COG method. As shown in FIG. 2, an external connection terminal 26 is formed at the end of the overhanging portion 19. A plurality of the external connection terminals 26 are formed so as to be spaced apart from each other in the direction perpendicular to the paper surface of FIG. One end on the inner side (right side in FIG. 2) of these external connection terminals 26 is connected to an input terminal of the driving IC 3, for example, an input bump. Further, a wiring board (not shown) is connected to one end on the outside (left side in FIG. 2) of these external connection terminals 26 by an appropriate connection connection method, for example, ACF, soldering, heat sealing, or the like.

  On the other hand, a wiring 27 is formed on the liquid crystal layer side of the overhang portion 19. A plurality of the wires 27 are formed at intervals from each other in the direction perpendicular to the paper surface of FIG. One end outside these wirings 27 is connected to an output terminal of the driving IC 3, for example, an output bump. Further, these wirings 27 extend toward the inside of the liquid crystal panel 2, that is, toward the liquid crystal layer 14, and a part thereof is connected to the line wiring 21 inside the liquid crystal panel 2. In addition, the other wirings 27 are connected to the conductive element on the color filter substrate 12 side which is the counter substrate by the conductive material 28 dispersed in the seal material 13.

  A light shielding member 32 and a coloring element 33 are formed on the inner surface of the second translucent substrate 16b constituting the color filter substrate 12, that is, on the liquid crystal side surface. An overcoat layer 34 is formed on the photosensitive resin such as an acrylic resin or a polyimide resin. Furthermore, a strip electrode 35 is formed thereon, and an alignment film 24b is formed thereon. The alignment film 24b is formed of polyimide, for example, and a rubbing process is performed on the surface thereof. By this rubbing treatment, the initial alignment of the liquid crystal molecules in the vicinity of the color filter substrate 12 is determined.

  For example, each of the coloring elements 33 is formed in a rectangular dot shape, and each coloring element 33 exhibits any one of the three primary colors B (blue), G (green), and R (red). . The coloring elements 33 of these colors are arranged in a stripe arrangement, a delta arrangement, a mosaic arrangement, and other appropriate arrangements as viewed from the observation side indicated by an arrow A. The coloring element 33 can also be formed by three primary colors of C (cyan), M (magenta), and Y (yellow).

  The light shielding member 32 is formed in a state in which a space between the plurality of coloring elements 33 is filled with a light shielding material such as Cr (chromium). The light shielding member 32 functions as a black mask and improves the contrast of an image displayed by light transmitted through the coloring element 33. The light shielding member 32 is not limited to being formed of a specific material such as Cr, and may be formed by, for example, stacking, that is, stacking, each of the B, G, and R coloring elements constituting the coloring element 33. can do.

  A plurality of strip electrodes 35 are provided on the color filter substrate 12, and each of them extends in the direction perpendicular to the paper surface of FIG. Further, the plurality of strip electrodes 35 are arranged in parallel to each other at regular intervals in the left-right direction in FIG. Thus, the plurality of strip electrodes 35 are formed in a stripe shape when viewed from the observation side indicated by the arrow A. These strip electrodes 35 are formed of a metal oxide such as ITO. Further, these band-like electrodes 35 extend in a direction perpendicular to the line wiring 21 when the element substrate 11 and the color filter substrate 12 are bonded together by the sealing material 13.

  The individual band-like electrodes 35 overlap with a plurality of dot electrodes 23 arranged in a row in a plan view when viewed from the direction of the arrow A. Thus, the area | region where the strip | belt-shaped electrode 35 and the dot electrode 23 overlap comprises the display dot D which is a unit of a display. The display region V is formed by arranging the plurality of display dots D in a matrix in the vertical direction and the horizontal direction when viewed from the direction of the arrow A.

  When color display is performed using the coloring elements 33 composed of the three colors B, G, and R as in the present embodiment, 3 corresponding to the three coloring elements 33 corresponding to the three colors B, G, and R are displayed. One display dot D forms one pixel. On the other hand, when monochrome display is performed in black and white or any one color, one pixel is formed by one display dot D.

  In FIG. 2, a reflective polarizer 36 is provided between the liquid crystal panel 2 and the light guide 6, that is, between the polarizing plate 18 b of the color filter substrate 12 and the light guide 6. The reflective polarizer 36 is a well-known optical element having a function of allowing specific polarized light to pass through and reflecting polarized light other than the polarized light. The light reflected by the reflective polarizer 36 is reintroduced into the light guide 6 from the light exit surface 6b and reused. Hereinafter, in this embodiment, such light is referred to as recycled light.

Hereinafter, the overall operation of the liquid crystal display device 1 of the present embodiment will be described.
In FIG. 2, when the light source 5 in the illumination device 4 is turned on, planar light is emitted from the light emitting surface 6 b of the light guide 6. This light is supplied to the liquid crystal layer 14 through the color filter substrate 12. Thus, while light is supplied to the liquid crystal layer 14, a scanning signal and a data signal are selectively applied to the plurality of strip electrodes 35 and dot electrodes 23 sandwiching the liquid crystal layer 14 in accordance with the image signal. For example, a scanning signal is applied to the strip electrode 35 and a data signal is applied to the dot electrode 23.

  When the voltage applied to the liquid crystal layer 14 is controlled for each display dot D as described above, the orientation of the liquid crystal molecules is similarly controlled for each display dot D, whereby light passing through the liquid crystal layer 14 is displayed. Modulated every D. Then, the modulated light is supplied to the polarizing plate 18a, and a desired image such as letters, numbers, figures, etc. is displayed on the observation side of the polarizing plate 18a. In this way, display using light transmitted through the liquid crystal panel 2, that is, transmissive display is performed.

  By the way, in general, it is desirable that the light supplied to the transmissive liquid crystal display device as in the present embodiment is uniform planar light. For this reason, in the conventional liquid crystal display device, the light-diffusion layer was provided in the light-projection surface of the light guide. As a result, the light emitted from the light guide is diffused to make the light luminance uniform. However, in the conventional liquid crystal display device, since the light diffusing layer is disposed on the entire surface of the light emitting surface, recycled light and external light incident on the light guide are diffused by the light diffusing layer. For this reason, it is difficult to effectively use recycled light and external light.

  On the other hand, in the liquid crystal display device 1 according to the present embodiment, the light diffusion pattern 9 is partially provided on the light emitting surface 6b of the light guide 6 as shown in FIG. According to the liquid crystal display device 1, the light emitted from the light guide 6 is diffused at the portion where the light diffusion pattern 9 is provided, and the luminance of the emitted light can be made uniform. On the other hand, in a portion where the light diffusion pattern 9 is not provided, light with high luminance can be emitted without diffusing light. As a result, uniform and high luminance illumination light can be obtained.

  In particular, as shown in FIG. 3, the light diffusion pattern 9 of this embodiment is partially reflected on the light emission surface 6b at a position corresponding to the emission position of the light Ld reflected by the light reflection pattern 8 and emitted from the light emission surface 6b. Therefore, the reflected light from the light reflecting pattern 8 can be emitted in a sufficiently diffused state. Further, the light emitting surface 6b where the light diffusing pattern 9 is not provided can emit light having a high luminance that is not subjected to the diffusion treatment, and therefore the light reflected by the light guide 6 is effectively used for display. it can.

  Hereinafter, the positional relationship between the light reflection pattern 8 and the light diffusion pattern 9 will be described. In this embodiment, (1) First, in FIG. 3, the light that needs to be diffused among the light emitted from the light emitting surface 6b is defined by the emission angle α. That is, light within the emission angle α is diffused. (2) Next, the reflection angle β of the light that causes the emission angle α of the light reflected by the light reflection pattern 8 is obtained based on optical conditions, for example, Snell's law. (3) When the reflection angle β at the light reflection pattern 8 is obtained, the light emission area on the light emission surface 6b is determined, and the light diffusion pattern 9 is formed in that area.

  In the above items, the method of setting the light emission angle α that needs to be diffused will be described. In this embodiment, the viewing angle characteristics relating to the intensity of light emitted from the light emission surface 6b are measured or simulated, The emission angle α is determined based on the half-value angle and the 1/10 value angle in the viewing angle characteristic. Specifically, the viewing angle characteristic along the BB direction and the viewing angle characteristic along the CC direction in FIG. 1 are measured or simulated, and B based on the viewing angle characteristic along the BB direction is measured or simulated. The outgoing angle α in the −B direction is determined, and the outgoing angle α in the CC direction is determined based on the viewing angle characteristics along the CC direction.

  FIG. 4 shows the viewing angle characteristic along the BB direction. FIG. 5 shows viewing angle characteristics along the line CC. These viewing angle characteristics are obtained, for example, when the intensity of light emitted from the light emitting surface 6 b of the light guide 6 is measured while changing the viewing angle at a position facing the light guide 6. 4 and 5, the light emission angle α = 0 ° is the intensity of the front surface of the light emission surface 6b in FIG. The angle of the position P1 at which the intensity is halved with respect to the light intensity in the normal direction is the half-value angle. The angle of the position P2 at which the intensity becomes 1/10 with respect to the light intensity in the normal direction is a 1/10 value angle.

  The “half-value angle” is (1) indicated by a value α1 (+) on the plus side from the angle 0 °, (2) indicated by a value α1 (−) on the minus side from the angle 0 °, or (3) It can be expressed by ((α1 (+) + α1 (−)) / 2 which is 1/2. These values are not necessarily the same value. In addition, the “1/10 value angle” is ( 1) represented by a value α2 (+) on the plus side from the angle 0 °, (2) represented by a value α2 (−) on the minus side from the angle 0 °, or (3) ½ of the full width (( α2 (+) + α2 (−)} / 2 These values are not necessarily the same value, and in the following description, the half-value angle and 1/10 value angle are When it is not necessary to limit to a specific one of 1) to (3), the half-value angle is displayed as “α1” and the 1/10 value angle is displayed as “α2”. To.

The light emission angle α set in FIG. 3 is set as an appropriate angle α within the range of the half-value angle α1 or more and the 1/10 value angle α2 or less in FIGS. For example, if the half-value angle is α1 = 10.8 ° and the 1/10 value angle is α2 = 20 °, the angle α is
10.8 ° ≦ α ≦ 20 °
Any one of the angles is set. The light within the angle α selected in this way is considered to be light with high intensity in viewing angle characteristics and strongly illuminating a specific part. Therefore, it is considered desirable to obtain uniform illumination light if the light in this region is diffused.

As described above, when the emission angle α of the outgoing light to be diffused is set, the light reflection angle β that brings about the outgoing angle α of the light reflected by the light reflection pattern 8 in FIG. Determined based on optical conditions. In the present embodiment, Snell's law is used as the optical condition. Snell's law is a law representing the relationship between the incident angle and the outgoing angle when light enters the boundary between two media having different refractive indexes. Specifically, the refractive index inside the light guide 6 is n1, the refractive index outside the light guide is n2, the light reflection angle at the light reflection pattern 8 is β, and the light is refracted by the light reflecting surface 6b. When the angle of light exiting to the outside is α, Snell's law
n1 · sin α = n2 · sin β (1)
The relationship is established. If this relationship is used, it is possible to obtain by calculation how much the light reflection angle β of the light reflection pattern 8 corresponds to the emission angle α that has already been set.

  If the light reflection angle β is thus known, it can be known from which region of the light exit surface 6b the emitted light Ld is emitted. If this light emission region is covered with the light diffusion pattern 9, the light emitted within the range of the emission angle α can be diffused by the light diffusion pattern 9. Thereby, only the light that needs to be diffused can be diffused by the light diffusion pattern 9. Light that is not subjected to the diffusion process is emitted from the region where the light diffusion pattern 9 is not provided in the light emission surface 6b. This light can maintain a high brightness as much as it is not diffused.

  Assuming that the light emission angle α in FIG. 3 is set to a certain angle within the range of 10.8 ° ≦ α ≦ 20 ° as described above, the light guide 6 is formed of acrylic. For example, the reflection angle β of the light Lr reflected by the light reflection pattern 8 is obtained as a certain angle within the angle range of 7.2 ° ≦ β ≦ 13.3 ° from the above equation (1). Thus, if the reflection angle β at the light reflection pattern 8 is known, it is possible to know which region of the light exit surface 6b the light reflected at the reflection angle β reaches, so the light diffusion pattern 9 is formed in that region. As a result, only the light reflected by the light reflection pattern 8 and requiring diffusion can be diffused by the light diffusion pattern 9 and emitted to the outside.

  Note that the emission angle α and the reflection angle β described above are along two directions of the BB direction and the CC direction in FIG. In forming the light diffusion pattern 9, the reflection angle β must be determined for directions other than the BB direction and the CC direction. In the present embodiment, the reflection angle β of this region is appropriately set based on the reflection angle β in the BB direction and / or the reflection angle β in the CC direction. For example, a total of four points including two points determined on the light output surface 6b by the reflection angle β in the BB direction and two points determined on the light output surface 6b by the reflection angle β in the CC direction are straight lines or circular arc lines. The contour of the light diffusing pattern 9 can be determined by connecting with an elliptical arc line, a long arc line, and other appropriate lines.

  Next, in the liquid crystal display device 1 of FIG. 2, the light reflecting layer 7 is provided to face the surface of the light guide 6 opposite to the light emitting surface 6 b. In this way, the light Lr from the LED 5 can be reflected by other than the light reflection pattern 8. In addition, external light such as sunlight or room light can be reflected by the light reflecting layer 7. These lights are emitted to the outside of the light guide 6 from the light emitting surface 6b where the light diffusion pattern 9 is not provided, in a state where the intensity is maintained without being diffused. Thereby, light can be used efficiently. In addition to the light Lr from the LED 5, external light can also be used, so that the display brightness can be increased.

  In the present embodiment, as shown in FIG. 2, a reflective polarizer 36 is provided so as to face the light exit surface 6 b of the light guide 6. Since the reflective polarizer 36 has a function of passing a specific polarized light and reflecting the other polarized light, if the reflective polarizer 36 is provided to face the light exit surface 6b, the reflective polarizer 36 can be omitted. For example, polarized light that is wasted by the polarizing plate 18b can be reused as recycled light. As a result, the light reflected by the light guide 6 can be used very efficiently.

  The liquid crystal display device 1 having the structure shown in FIG. 2 is a transmissive liquid crystal display device capable of so-called micro-reflection display. In this micro-reflection type display, the light reflected from the reflection layer 7 of the light guide 6, the light exit surface 6b, etc. is displayed without using the light from the light source 5 in the illumination device 4. Is. Although it may be difficult to perform high-definition display using the entire display region V, it is considered that this fine reflection type display is sufficient for time display and other partial and simple displays. If this fine reflection type display is used, the power consumption of the liquid crystal display device 1 can be greatly reduced. If the light diffusing pattern 9 is partially provided on the light emitting surface 6b of the light guide 6 as in the present invention, the liquid crystal panel 2 emits light with high luminance by effectively using the reflected light from the light guide 6. This is particularly advantageous when performing a micro-reflection display.

(Second embodiment of illumination device and electro-optical device)
Hereinafter, other embodiments of the illumination device and the electro-optical device according to the present invention will be described. In this embodiment, in FIG. 4 which shows the viewing angle characteristic of the light guide 6 along the BB direction of FIG.
Regarding the half-value angle,
α1 (−) = 11.9 °, α1 (+) = 10.0 °,
Regarding 1/10 value angle,
α2 (−) = 19.8 °, α2 (+) = 17.8 °
Suppose that

Further, in FIG. 5 showing the viewing angle characteristic along the CC direction of FIG.
Regarding the half-value angle,
α1 (−) = 7.2 °, α1 (+) = 10.6 °
1/10 value angle
α2 (−) = 14.6 °, α2 (+) = 17.1 °
Suppose that

  Next, based on the positive half-value angle α1 (+) = 10.0 ° in FIG. 4 (B-B direction), the reflection angle on the upper end side of the light reflection pattern 8 as shown in FIG. For β, β = 6.7 ° is obtained from Snell's law. Then, β = 8.0 ° is obtained from Snell's law for the reflection angle β on the lower end side of the light reflection pattern 8 on the basis of the half-value angle α1 (−) = 11.9 ° on the negative side. Thereby, the dimension of the light diffusion pattern 9 corresponding to the half-value angle along the BB direction in FIG. 9A is determined.

  Next, based on the 1/10 value angle α2 (+) = 17.8 ° on the plus side of FIG. 4 (BB direction), as shown in FIG. 7B, the upper end side of the light reflection pattern 8 Β = 11.8 ° is obtained from Snell's law. Then, β = 13.1 ° is obtained from Snell's law for the reflection angle β on the lower end side of the light reflection pattern 8 based on the minus 1/10 value angle α2 (−) = 19.8 °. Thereby, the dimension of the light diffusion pattern 9 corresponding to the 1/10 value angle along the BB direction in FIG. 9B is determined.

  Next, based on the positive half-value angle α1 (+) = 10.6 ° in FIG. 5 (CC direction), the reflection angle on the upper end side of the light reflection pattern 8 is shown in FIG. For β, β = 7.1 ° is obtained from Snell's law. Then, β = 4.8 ° is obtained from Snell's law for the reflection angle β on the lower end side of the light reflection pattern 8 based on the half-value angle α1 (−) = 7.2 ° on the minus side. Thereby, the dimension of the light diffusion pattern 9 corresponding to the half-value angle along the CC direction in FIG. 9A is determined.

  Next, based on the plus-side 1/10 value angle α2 (+) = 17.1 ° in FIG. 5 (CC direction), as shown in FIG. Β = 11.4 ° is obtained from Snell's law. Then, β = 9.7 ° is obtained from Snell's law for the reflection angle β on the lower end side of the light reflection pattern 8 based on the minus 1/10 value angle α2 (−) = 14.6 °. Thereby, the dimension of the light diffusion pattern 9 corresponding to the 1/10 value angle along the CC direction in FIG. 9B is determined.

  As described above, the position of the light diffusion pattern 9 with respect to the light reflection pattern 8 is determined based on the half-value angle, that is, two positions in the BB direction and two positions in the CC direction, for a total of four positions. If the four points corresponding to these half-value angles are connected by elliptical arc lines, a light diffusion pattern 9 having a contour as shown in FIG. 9A is obtained. 7B and 8B, based on the 1/10 value angle, the position of two points in the BB direction and the position of two points in the CC direction, a total of four positions. Determined. If these four points corresponding to 1/10 value angles are connected by elliptical arc lines, a light diffusion pattern 9 having a contour as shown in FIG. 9B is obtained.

  Of course, the light diffusion pattern 9 can be formed by the contour shape obtained as described above. However, according to the present invention, the shape of the light diffusion pattern 9 is not limited to the critical shape, and FIG. ) And FIG. 9B may be used.

  Note that the contour line of the light diffusion pattern 9 is not limited to the elliptical arc line, and may be a straight line, an arc line, a long arc line, or any other appropriate line as necessary. If possible, the viewing angle characteristics are measured or simulated with respect to a large number of cross-sectional lines other than the BB line and the CC line in FIG. 1, and the contour line of the light diffusion pattern 9 is determined based on the large number of viewing angle characteristics. It is desirable.

(Other Embodiments Regarding Electro-Optical Device and Illumination Device)
The present invention has been described with reference to the preferred embodiments. However, the present invention is not limited to the embodiments, and various modifications can be made within the scope of the invention described in the claims. For example, in FIG. 2, the reflective polarizer 36 may not be provided in some cases. Further, the reflective layer 8 may not be provided depending on circumstances.

  In the above embodiment, the present invention is applied to a transmissive liquid crystal display device. However, the present invention can also be applied to a transflective liquid crystal display device. A transflective liquid crystal display device is a liquid crystal display device that has both a reflective display function and a transmissive display function, and can selectively execute one of them. More specifically, in this liquid crystal display device, a light reflecting film having a function of transmitting light is formed inside the liquid crystal panel, and the light reflected by the reflecting film is used when performing a reflective display. When transmissive display is performed, light transmitted through the reflective film is used.

  In the above embodiment, the present invention is applied to an active matrix type liquid crystal display device using a TFD element which is a two-terminal switching element. However, the present invention is applied to a TFT (Thin) which is a three-terminal switching element. The present invention can also be applied to a liquid crystal display device using a film transistor element. Further, the present invention can be applied to a simple matrix liquid crystal display device that does not use a switching element.

  In the above embodiment, the present invention is applied to a liquid crystal display device which is one type of electro-optical device. However, the present invention is applicable to any electro-optical device having a structure in which display is performed by receiving light. Is also applicable.

(Embodiment of electronic device)
Next, an embodiment of an electronic device according to the present invention will be described with reference to the drawings.
FIG. 10 shows a block diagram of an embodiment of an electronic apparatus according to the present invention. The electronic apparatus shown here includes a liquid crystal display device 71 and a control circuit 70 that controls the liquid crystal display device 71. The liquid crystal display device 71 includes a liquid crystal panel 72, an illumination device 78, and a drive circuit 73 configured with a semiconductor IC or the like. The control circuit 70 includes a display information output source 74, a display information processing circuit 75, a power supply circuit 76, and a timing generator 77.

  The display information output source 74 includes a memory such as a ROM (Read Only Memory) or a RAM (Random Access Memory), a storage unit such as a magnetic recording disk or an optical recording disk, and a tuning circuit that tunes and outputs a digital image signal. Have The display information output source 74 supplies display information to the display information processing circuit 75 in the form of an image signal or the like in a predetermined format based on various clock signals generated by the timing generator 77.

  The display information processing circuit 75 includes various well-known circuits such as a serial-parallel conversion circuit, an amplification / inversion circuit, a rotation circuit, a gamma correction circuit, and a clamp circuit, and executes processing of input display information to obtain image information. Are supplied to the drive circuit 73 together with the clock signal CLK. The drive circuit 73 includes a scanning line drive circuit, a data line drive circuit, and an inspection circuit. The power supply circuit 76 supplies a predetermined voltage to each of the above components.

  The liquid crystal display device 71 can be configured by, for example, the liquid crystal display device 1 shown in FIG. According to the liquid crystal display device 1 shown in FIG. 1, by devising the light guide 6, the reflected light reflected by the light guide plate 6 is effectively used to provide uniform and high luminance planar light to the liquid crystal panel 2. Since it can be supplied, in the liquid crystal display device 71 of FIG. 10 using this, bright display with uniform brightness and uniform brightness can be performed.

  Next, FIG. 11 shows an embodiment in which the present invention is applied to a mobile phone which is an example of an electronic apparatus. A cellular phone 80 shown here has a main body portion 81 and a display body portion 82 provided on the main body portion 81 so as to be opened and closed. A display device 83 configured by an electro-optical device such as a liquid crystal display device is disposed inside the display body portion 82, and various displays relating to telephone communication can be visually recognized on the display body portion 82 on the display screen 84. Operation buttons 86 are arranged on the main body 81.

  An antenna 87 is attached to one end of the display body portion 82 so as to be extendable. A speaker (not shown) is arranged inside the receiver unit 88 provided at the upper part of the display body unit 82. In addition, a microphone (not shown) is incorporated in the transmitter 89 provided at the lower end of the main body 81. A control unit for controlling the operation of the display device 83 is stored in the main body 81 or the display body unit 82 as a part of the control unit that controls the entire mobile phone or separately from the control unit. The

  The display device 83 can be configured by, for example, the liquid crystal display device 1 shown in FIG. According to the liquid crystal display device 1 shown in FIG. 1, by devising the light guide 6, the reflected light reflected by the light guide plate 6 can be effectively used to make the liquid crystal panel 2 uniform and high brightness planar light. 11 can also be used, and even in the mobile phone 80 of FIG. 11 using this, a bright display with uniform brightness and uniform brightness can be displayed in the display screen 84.

(Modification)
In addition to the mobile phone described above, the electronic device according to the present invention includes a personal computer, a liquid crystal television, a digital still camera, a wristwatch, a viewfinder type or a monitor direct view type video tape recorder, a car navigation device, a pager, An electronic notebook, a calculator, a word processor, a workstation, a video phone, a POS terminal, and other various devices can be considered.

1 is a perspective view showing an electro-optical device according to an embodiment of the present invention in an exploded state. It is sectional drawing according to the BB line of FIG. It is sectional drawing to which the part shown by the arrow D of FIG. 2 was expanded. It is a graph which shows the viewing angle characteristic of the emitted light of the part along the BB line in the illuminating device of FIG. It is a graph which shows the viewing angle characteristic of the emitted light of the part along CC line in the illuminating device of FIG. It is a figure for demonstrating the position which provides a light-diffusion pattern. FIG. 6 is a diagram illustrating a main part of another embodiment of the electro-optical device according to the invention. It is a figure which shows the other principal part of embodiment shown in FIG. It is a top view which shows the light-diffusion pattern used by embodiment shown in FIG.7 and FIG.8. It is a block diagram which shows one Embodiment of the electronic device which concerns on this invention. It is a perspective view which shows other embodiment of the electronic device which concerns on this invention.

Explanation of symbols

1. 1. liquid crystal display device (electro-optical device), LCD panel (electro-optical panel),
3. Driving IC, 4. Lighting device 5,105. LED (light source),
6,106. Light guide, 6a, 106a. Light incident surface, 6b, 106b. Light exit surface,
7). Light reflecting layer; Light reflection pattern, 9,109. Light diffusion pattern,
11. Element substrate, 12. 12. color filter substrate; Sealing material, 14. Liquid crystal layer,
15. Spacers, 16a, 16b. Substrates, 17a, 17b. Retardation plate,
18a, 18b. Polarizing plate, 19. 20. Overhang part, Line wiring,
22. TFD element, 23. Dot electrodes, 24a, 24b. Alignment film,
25. ACF, 26. 26. External connection terminal Wiring, 28. Conductive material,
32. Light shielding member, 33. Coloring elements, 34. Overcoat layer, 35. Strip electrode,
36. Reflective polarizer, 71. Liquid crystal display device, 80. Mobile phones (electronic devices),

Claims (10)

A light source that generates light;
A light guide that introduces light generated from the light source from the light incident surface and emits the light from the light exit surface;
A light diffusion pattern partially provided on the light exit surface;
A light reflection pattern provided on a surface opposite to the light emitting surface of the light guide,
The illumination device, wherein the light diffusion pattern is provided on the light emitting surface at a position corresponding to an emission position of light reflected from the light reflecting pattern and emitted from the light emitting surface.   2. The illumination device according to claim 1, wherein the light in a region corresponding to an appropriate angle within a range of a half-value angle or more and a 1/10 value angle or less in a viewing angle characteristic of light emitted from the light exit surface can be diffused. The light diffusing pattern is provided on the lighting device. The lighting device according to claim 2.
An appropriate angle in the range of the half-value angle and the 1/10 value angle or less in the viewing angle characteristic of the light emitted from the light exit surface is α, the refractive index inside the light guide is n1, and the When the refractive index outside the light guide is n2,
n1 · sinα = n2 · sinβ
The light diffusing pattern is provided at a position that blocks light reflected from the light reflecting pattern within the range of the angle β determined by The lighting device according to claim 3.
In a position that blocks each light reflected from the light reflection pattern in a different direction within a plurality of ranges of the angle β determined based on viewing angle characteristics along a plurality of different linear directions crossing the plane of the light emitting surface. An illumination device characterized by providing a light diffusion pattern. In the illuminating device as described in any one of Claims 1-4,
The illumination device according to claim 1, wherein a surface of the light guide opposite to the light exit surface is composed of the light reflection pattern and a mirror surface.   6. The lighting device according to claim 1, wherein a light reflection layer is provided to face a surface of the light guide opposite to a light emitting surface. 7.   7. The illumination device according to claim 1, further comprising a reflective polarizer facing the light emitting surface. 8.   A lighting device according to any one of claims 1 to 7, and an electro-optical panel that receives light from the lighting device and performs display, and a light emission surface of the light guide is the electric device. An electro-optical device provided to face an optical panel. An electro-optical device comprising: an illumination device; and an electro-optical panel that receives light from the illumination device and performs display.
A light source that generates light;
A light guide that introduces light generated from the light source from the light incident surface and emits the light from the light exit surface;
A light diffusion pattern partially provided on the light exit surface;
A light reflection pattern provided on a surface opposite to the light emitting surface of the light guide,
The light diffusion pattern is provided on the light exit surface at a position corresponding to an exit position of light reflected from the light reflection pattern and emitted from the light exit surface,
An electro-optical device, wherein a light emitting surface of the light guide is provided to face the electro-optical panel. An electronic apparatus comprising the electro-optical device according to claim 8.

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