JP4483233B2 - Surface light source and liquid crystal display device - Google Patents

Description

The present invention relates to a surface light source for displaying a stereoscopic image on a liquid crystal display panel, and a liquid crystal display device .

Conventionally, as a liquid crystal display device for displaying a stereoscopic image, an image for the left eye is displayed by every other column of pixels of the liquid crystal display panel, and an image for the right eye is displayed by every other column of pixels. And right-eye images are divided into the left-eye direction and the right-eye direction of the display observer for the light emitted from the pixels in one row and the light from the pixels in the other row of the liquid crystal display panel. Alternatively, the left and right eyes of the observer can be observed through a parallax barrier formed in stripes by alternately arranging a plurality of transmission parts and light-shielding parts parallel to the pixel rows of the liquid crystal display panel. (See Patent Documents 1, 2, and 3).
Japanese Laid-Open Patent Publication No. 3-19889 JP-A-7-005400 Japanese Patent Laid-Open No. 10-268230

  However, since a conventional liquid crystal display device that displays a stereoscopic image displays an image for the left eye by every other row of pixels of the liquid crystal display panel and an image for the right eye by every other row of pixels, The image resolution is low.

  Moreover, in the conventional liquid crystal display device, a lenticular lens having a lens pitch corresponding to the pixel pitch of the liquid crystal display panel, or a parallax barrier having a transmissive portion pitch corresponding to the pixel pitch, and each lens portion or transmissive portion of the lenticular lens are The pixels in each row of the liquid crystal display panel must be arranged with high precision in a predetermined positional relationship, and thus manufacturing is difficult.

An object of the present invention is to provide a surface light source capable of displaying a high-resolution three-dimensional image on a liquid crystal display device and to provide a liquid crystal display device capable of displaying a high-resolution three-dimensional image. is there.

The surface light source according to claim 1 is made of a plate-shaped transparent member, and has a light guide plate having a predetermined thickness between one plate surface and the other plate surface, and a first of the light guide plates. A first light-emitting element that emits light toward the end face; and a second light-emitting element that emits light toward the second end face of the light guide plate facing the first end face. The optical plate has a first parallel region in which a predetermined region of the one plate surface is formed in parallel to a plane perpendicular to the first end surface or the second end surface, and the first parallel region The light guide plate in the region is formed in a second parallel region formed so that the other plate surface is parallel to the one plate surface , and on the first end surface side than the second parallel region. And the thickness at the first end face side is the thickness at the second parallel region according to the distance from the second parallel region. A first inclined region that is thinner than the second parallel region, and the thickness on the second end surface side in accordance with the distance from the second parallel region. A second inclined region that is thinner than the thickness of the second parallel region, and each of the second parallel region, the first inclined region, and the second inclined region includes the first end surface or the second inclined region, respectively. A plurality of grooves extending in a direction along the second end surface are formed on the other plate surface .

The surface light source according to claim 2 is the surface light source according to claim 1, wherein each of the grooves has a V-shaped cross section.

The surface light source according to claim 3 is the surface light source according to claim 2, wherein two sides of the groove centered on the apex angle of the groove having a V-shaped cross-section are a method for the plane. It is formed at an angle symmetrical to each other with respect to the line.

The surface light source according to claim 4 is the surface light source according to any one of claims 1 to 3, wherein the grooves are arranged at a predetermined constant pitch over the entire area of the first parallel region. It is characterized by.

The surface light source according to claim 5 is the surface light source according to any one of claims 1 to 4, wherein the first inclined region corresponds to the one plate surface according to a distance from the second parallel region. The inclination angle of the other plate surface is different.

The surface light source according to claim 6 is the surface light source according to claim 5, wherein the inclination angle of the first inclined region is larger on the first end surface side than on the second parallel region side. It is characterized by being.

The surface light source according to claim 7 is the surface light source according to any one of claims 1 to 6, wherein the second inclined region is relative to the one plate surface in accordance with a distance from the second parallel region. The inclination angle of the other plate surface is different.

The surface light source according to claim 8 is the surface light source according to claim 7, wherein the inclination angle of the second inclined region is larger on the second end surface side than on the second parallel region side. It is characterized by being.

The surface light source according to claim 9 is the surface light source according to any one of claims 1 to 8, wherein the first inclined region and the second inclined region are formed in symmetrical shapes. It is characterized by.

The liquid crystal display device according to claim 10 is made of a plate-shaped transparent member, and has a light guide plate having a predetermined thickness between one plate surface and the other plate surface, and a first of the light guide plates. A first light emitting element that emits light toward the end face of the light emitting element, a second light emitting element that emits light toward the second end face of the light guide plate facing the first end face, and the light guide plate A liquid crystal display panel disposed on the one plate surface side and having a plurality of display pixels formed in a predetermined display area, wherein the predetermined region of the one plate surface is the first region of the light guide plate A first parallel region formed parallel to an end surface or a plane perpendicular to the second end surface, and the light guide plate in the first parallel region has the other plate surface of the one plate a second parallel region formed so as to be parallel to the plane than said second parallel region first A first inclined region formed on an end surface side, wherein the thickness on the first end surface side is thinner than the thickness on the second parallel region according to the distance from the second parallel region; The second end surface is formed on the second end surface side with respect to the parallel region, and the thickness on the second end surface side is thinner than the thickness on the second parallel region according to the distance from the second parallel region. A plurality of grooves extending in a direction along the first end surface or the second end surface, respectively, the second parallel region, the first inclined region, and the second inclined region. Is formed on the other plate surface .
The liquid crystal display device according to claim 11 is the liquid crystal display device according to claim 10, wherein light from the first light emitting element or the second light emitting element is the one plate surface in the first parallel region. To the display area.
A liquid crystal display device according to a twelfth aspect of the invention is the liquid crystal display device according to the tenth or eleventh aspect, wherein the liquid crystal display panel selectively displays a left-eye image and a right-eye image on the liquid crystal display panel; A first lighting state in which the first light emitting element is set to a light emitting state and the second light emitting element is set to a non-light emitting state, and the second light emitting element is set to a non-light emitting state and the second light emitting element is set to And a lighting control unit that switches a second lighting state to be in a light emitting state in synchronization with a display switching timing between the left-eye image and the right-eye image.
The liquid crystal display device according to a thirteenth aspect of the present invention is the liquid crystal display device according to the twelfth aspect, wherein the left-eye image and the right-eye image are respectively composed of a red component image, a green component image, and a blue component image. The control unit selectively switches the color component images to display on the liquid crystal display panel.
The liquid crystal display device according to a fourteenth aspect is the liquid crystal display device according to the thirteenth aspect, wherein the first light emitting element and the second light emitting element emit red light, green light, and blue light, respectively. The lighting control unit causes the first light emitting element or the second light emitting element to emit light of a color corresponding to a color component of an image displayed on the liquid crystal display panel.
A liquid crystal display device according to claim 15 is the liquid crystal display device according to any one of claims 10 to 14, wherein the first plate surface is interposed between the light guide plate and the liquid crystal display panel. A first diffusion plate whose degree of diffusion with respect to the light emitted from one light emitting element is higher than the degree of diffusion with respect to the light emitted from the second light emitting element via the one plate surface ; A second degree of diffusion of light emitted from the second light emitting element through the plate surface is higher than a degree of diffusion of light emitted from the first light emitting element through the one plate surface . And a diffusion plate.

ADVANTAGE OF THE INVENTION According to this invention, the surface light source which can display a high-resolution three-dimensional image on a liquid crystal display device can be provided. In addition, a liquid crystal display device that can display a stereoscopic image with high resolution can be provided.

  1 to 10 show an embodiment of the present invention. FIG. 1 is an exploded perspective view of a liquid crystal display device, and FIG. 2 is a side view of the liquid crystal display device.

  As shown in FIGS. 1 and 2, the liquid crystal display device has a display area A in which a plurality of pixels (not shown) are arranged in a matrix, so that the pixels can be observed with separate left and right eyes. The left-eye image data and the right-eye image data are selectively written, and the left-eye image and the right-eye image are selectively displayed according to the left-eye and right-eye image data. A display panel 1, a surface light source 8 disposed on the opposite side (hereinafter referred to as an incident side) of the liquid crystal display panel 1 from the observation side (upper side in the figure), and the liquid crystal display panel 1 and the surface light source 8. First and second directional diffusers 17 and 18 disposed between them, and a control means 19 for driving the liquid crystal display panel 1 and the surface light source 8 are provided.

  The liquid crystal display panel 1 is an active matrix liquid crystal display panel using TFTs (thin film transistors) as active elements, and the internal structure thereof is not shown, but a pair of transparent substrates 2 and 3 bonded via a frame-shaped sealing material. Among them, a plurality of transparent pixel electrodes arranged in a matrix in the row direction and the column direction on one substrate, for example, the surface of the incident side substrate 2 facing the observation side substrate 3 are connected to these pixel electrodes, respectively. A plurality of TFTs, a plurality of gate wirings for supplying gate signals to the TFTs in each row, and a plurality of gate wirings for supplying gate signals to the TFTs in each column, respectively. On the surface facing the incident side substrate 2, a single-film shape that forms a plurality of pixels arranged in a matrix by regions facing the pixel electrodes, respectively. A transparent counter electrode is provided, a liquid crystal layer is provided in a region surrounded by the sealing material between the substrates 2 and 3, and polarizing plates 4 and 5 are disposed on the outer surfaces of the pair of substrates 2 and 3, respectively. It becomes the composition.

  The liquid crystal display panel 1 is, for example, a TN (twisted nematic) liquid crystal display panel in which the liquid crystal molecules of the liquid crystal layer are twist-aligned between the pair of substrates 2 and 3 with a twist angle of substantially 90 °, or , A non-twisted homogeneous alignment type liquid crystal display panel in which the liquid crystal molecules of the liquid crystal layer are aligned homogeneously with the molecular long axis aligned in one direction, and the incident side polarizing plate 4 is formed on the outer surface of the pair of substrates 2 and 3. And the display-side polarizing plate 5 are arranged so that their transmission axes are substantially orthogonal or substantially parallel to each other.

  Further, on the incident side substrate 2 of the liquid crystal display panel 1, driver mounting portions 2a and 2b are formed on one end edge in the row direction and one end edge in the column direction so as to project outward from the observation side substrate 3. The plurality of gate lines are connected to a gate side driver 6 mounted on the driver mounting section 2a in the row direction, and the plurality of data lines are connected to the data side driver 7 mounted on the driver mounting section 2b in the column direction. And the counter electrode is connected to the gate-side driver via a counter connection wiring formed in one or both of a cross connection portion provided in a substrate bonding portion made of the sealing material and the driver mounting portions 2a and 2b. 6 and the data side driver 7 are connected to one or both of the reference potentials.

  The surface light source 8 has a peak of emitted light intensity in a first direction inclined at a predetermined angle in the direction of one of the left and right eyes of the display observer with respect to the normal line of the liquid crystal display panel 1. Directivity in which there is a first light beam having a directivity and a peak of emitted light intensity in a second direction inclined at a predetermined angle in the direction of the other eye of the observer with respect to the normal line. The surface light source 8 is emitted to the liquid crystal display panel 1. The surface light source 8 includes a light guide plate 9 and first and first light sources disposed on both ends of the light guide plate 9. 2 light emitting elements 16a and 16b.

  3 is a side view of the light guide plate 9, and FIG. 4 is an enlarged side view of one end side of the light guide plate 9. The light guide plate 9 is made of a plate-like transparent member, and the transparent members 2 are opposed to each other. The first and second incident end faces 10a and 10b, on which light is incident, are formed on one of the two opposing plate surfaces (upper surface in the figure) of the transparent member, and the incident end face 10a , 10b and is formed on the horizontal emission surface 11 for emitting the light guided in the transparent member and the other plate surface (lower surface in the drawing) of the transparent member, and the incident end surfaces 10a, 10b A reflection surface that reflects the light incident on the transparent member toward the emission surface;

  The reflection surface 12 of the light guide plate 9 is formed in a parallel plane between the two end surfaces, that is, between the first and second incident end surfaces 10a and 10b, substantially parallel to the emission surface 11. The portions on both sides of the parallel surface on the incident end faces 10a and 10b, that is, both end sides of the reflecting surface 12, are inclined toward the parallel plane, and the inclination angles become closer to the incident end faces 10a and 10b, respectively. An inclined surface portion 13 in which a plurality of inclined surfaces having a large inclination angle is continuous is formed of a directional reflecting surface formed continuously with the parallel surface.

  In this embodiment, the inclined surface portions 13 on both sides of the parallel surface of the reflecting surface 12 have three inclined surfaces 13a, 13b, 13c continuous in the direction from the incident end surfaces 10a, 10b toward the central portion, and The inclination angles of the three inclined surfaces 13a, 13b, and 14b (the angles with respect to the light exit surface 11 of the light guide plate 9) are respectively the first inclined surfaces 13c on the incident end surfaces 10a and 10b side from the third inclined surface 13c on the central portion side. A directional reflecting surface is formed by the parallel surface and the inclined surface portion 13 including the three inclined surfaces 13a, 13b, and 13c on both sides of the parallel surface. Yes.

  The light guide plate 9 is made of an acrylic resin having a refractive index of 1.49, and has a length of 46 mm and a central plate between two end surfaces (between the first and second incident end surfaces 10a and 10b). It is a rectangular plate having a thickness of 2.1 mm, and the inclined surface portions 13 on both ends of the reflecting surface 12 are formed over a length of 14 mm from the incident end surfaces 10a and 10b, respectively. The length portion is formed on a parallel plane substantially parallel to the emission surface 11.

  In this embodiment, the inclined surface portions 13 on both end sides of the reflecting surface 12 are formed over a length of 5 mm from the incident end surfaces 10a and 10b as shown in FIG. A first inclined surface 13a inclined at an inclination angle of 6 ° with respect to the surface 11, and a length of 5 mm from the end of the first inclined surface 13a, and an inclination of 4 ° with respect to the emitting surface 11 A second inclined surface 13b inclined at an angle, and a third inclined surface formed over a length of 4 mm from the end of the second inclined surface 13b and inclined at an inclination angle of 2 ° with respect to the emission surface 11 13c.

  5 and 6 are enlarged views of the V part and the VI part of FIG. 4, and the light guide plate 9 has a reflective surface 12 over the substantially entire area of the light guide plate 9 in the width direction (first and second incidences). A plurality of horizontally long groove portions 14 along a direction parallel to the end faces 10a and 15b are formed in parallel with each other at a predetermined pitch.

  Each of the plurality of horizontally elongated grooves 14 is inclined at an angle of 50 ° with respect to the normal line h of the light exit surface 11 of the light guide plate 9 in the first incident end face 10a direction and the second incident end face 10b direction, respectively. The V-shaped groove portions having an apex angle of 100 ° and a depth of 20 μm, and these horizontally long groove portions 14 are formed at a pitch of 100 μm.

  In this embodiment, the plurality of horizontally long grooves 14 are formed in portions near the first and second incident end faces 10a and 10b, for example, 40 mm excluding portions of 3 mm length from the incident end faces 10a and 10b. It is formed in the area of the length.

  The light exit surface 11 of the light guide plate 9 is formed except for the portions near the first and second incident end surfaces 10a and 10b, and both ends of the light exit surface 11 and the first and second incident surfaces. An exit side inclined surface that inclines toward the central portion between the two end surfaces at a portion between the end surfaces 10a and 10b and reflects the light incident from the incident end surfaces 10a and 10b toward the reflecting surface 12. 15 is formed.

  In this embodiment, as shown in FIG. 4, the exit surface 11 is 3 mm in length from the formation region of the horizontally elongated groove 14 of the reflection surface 12, that is, the first and second incident end surfaces 10a and 10b. It is formed in a region having a length of 40 mm excluding the portion, and a length of 3 mm from both ends of the emission surface 11 and the first and second incident end surfaces 10a and 10b, that is, the incident end surfaces 10a and 10b. Of the three inclined surfaces 13a, 13b, and 13c that form the inclined surface portions 13 on both ends of the reflecting surface 12 of the light guide plate 9, the same as the first inclined surface 13a on the incident end surfaces 10a and 10b side. An exit side inclined surface 15 that is inclined in a direction opposite to the first inclined surface 13a at an inclination angle of 6 ° is formed.

  As described above, the thickness of the central portion between the two end surfaces of the light guide plate 9 is 2.1 mm, and the three inclined surfaces 13a forming the inclined surface portions 13 at both ends of the reflecting surface 12 of the light guide plate 9 are provided. , 13b, and 13b have lengths of 5 mm, 5 mm, and 4 mm, respectively, and inclination angles of these inclined surfaces 13a, 13b, and 13b (angles with respect to the emission surface 11 of the light guide plate 9) are 6 °, 4 °, and 2 °, respectively. In addition, the length and the inclination angle of the inclined surface 15 formed in the portion between both ends of the exit surface 11 of the light guide plate 9 and the first and second incident end surfaces 10a and 10b (of the light guide plate 9). Since the angle with respect to the emission surface 11 is 3 mm and 6 °, the heights of the first and second incident end faces 10a and 10b of the light guide plate 9 are 0.8 ± 0.2 mm, respectively.

  The surface light source 8 selectively emits light from the first and second light emitting elements 16a and 16b arranged to face the first and second incident end faces 10a and 10b of the light guide plate 9, respectively. The light from these light emitting elements 16a and 16b is guided by the light guide plate 9 and emitted from the emission surface 11. The light is emitted from the first light emitting element 16a and enters the light guide plate 9. The light incident from the end face 10a and the light emitted from the second light emitting element 16b and incident on the light guide plate 9 from the second incident end face 10b are respectively applied to both ends of the reflection surface 12 of the light guide plate 9. Reflected by the parallel surface of the central portion between the two end surfaces of the inclined surface portion 13 and the reflecting surface 12 formed of the three inclined surfaces 13a, 13b, 13c, and the light incident from the first incident end surface 10a. The light guide plate 9 The directivity in which the peak of the emitted light intensity exists from the exit surface 11 in a first direction inclined at a predetermined angle in a direction opposite to the first incident end face 10a with respect to the normal h of the exit surface 11 is provided. The light incident on the second incident end face 10 b is emitted from the second incident end face 10 b from the outgoing face 11 of the light guide plate 9 with respect to the normal h of the outgoing face 11. The light is emitted as the second light having directivity in which the peak of the emitted light intensity exists in the second direction inclined at a predetermined angle in the opposite direction to 10b.

  FIG. 7 shows a state in which the first light is emitted from the surface light source 8. At this time, the first light emitting element 16a is turned on and the second light emitting element 16b is turned off.

  The light emitted from the first light emitting element 16a is incident on the light guide plate 9 from the first incident end face 10a, and as shown by the arrow in FIG. The surface 11 is guided through the light guide plate 9 while being reflected by total reflection at the interface between the reflection surface 12 and the emission surface 11 and the outside air (an air layer having a refractive index of 1), and in the process, the reflection surface Among the light reflected by the light 12, the light incident on the interface between the emission surface 11 and the outside air at an incident angle smaller than the critical angle of line reflection (the angle with respect to the normal h of the emission surface 11 is small) passes through the interface. Then, the light is emitted from the emission surface 11.

  FIG. 8 shows a state in which the second light is emitted from the surface light source 8. At this time, the second light emitting element 16b is turned on and the first light emitting element 16a is turned off.

  The light emitted from the second light emitting element 16b enters the light guide plate 9 from the first incident end face 10a, and as shown by the arrow in FIG. The light is guided through the light guide plate 9 while being reflected by total reflection at the interface between the reflecting surface 12 and the emitting surface 11 and the outside air, and in the process, out of the light reflected by the reflecting surface 12, Light incident on the interface between the exit surface 11 and the outside air at an incident angle smaller than the critical angle for line reflection exits from the exit surface 11.

  The reflection surface 12 of the light guide plate 9 is formed such that a central portion between the two end surfaces is a parallel surface substantially parallel to the emission surface 11, and the central portion is provided at both end sides of the reflection surface 12. The three inclined surfaces 13a, 13b, 13c that are inclined toward the surface are continuous, and the inclination angle (angle with respect to the emission surface 11) of the plurality of inclined surfaces 13a, 13b, 13c is the center in the length direction of the light guide plate 9 Since this is a directional reflecting surface on which the inclined surface portion 13 that is sequentially set at a steep angle is formed from the third inclined surface 13c on the portion side toward the first inclined surface 13a on the incident end surface 10a, 10b side, the first Light emitted from one light emitting element 16a and incident on the light guide plate 9 from the first incident end face 10a is three inclined surfaces of the inclined surface portion 13 formed on both end sides of the reflecting surface 12 of the light guide plate 9. 13a, 13b, 13c and the above As shown in FIG. 7, the light beam is reflected by the central parallel surface and predetermined in the direction opposite to the first incident end surface 10 a with respect to the normal line of the emission surface 11 from the entire area of the emission surface 11 of the light guide plate 9. The light is emitted as first light having directivity in which the peak of the emitted light intensity exists in the first direction inclined at an angle, emitted from the second light emitting element 16b, and applied to the light guide plate 9. The light incident from the incident end surface 10b is reflected by the three inclined surfaces 13a, 13b, 13c of the inclined surface portion 13 formed on both ends of the reflecting surface 12 of the light guide plate 9 and the parallel surface of the central portion. As shown in FIG. 8, the light exits from the entire exit surface 11 of the light guide plate 9 in a second direction inclined at a predetermined angle in a direction opposite to the second incident end surface 10 b with respect to the normal line of the exit surface 11. The second light with the directivity where the peak of the incident light intensity exists It is emitted.

  In this embodiment, the thickness of the central portion in the length direction of the light guide plate 9 is 2.1 mm, and the inclined surface portions 13 on both ends of the reflection surface 12 of the light guide plate 9 are respectively formed from the incident end surfaces 10a and 10b. A first inclined surface 13a formed over a length of 5 mm and inclined at an inclination angle of 6 ° with respect to the emission surface 11 of the light guide plate 9, and over a length of 5 mm from the end of the first inclined surface 13a A second inclined surface 13b formed at an inclination angle of 4 ° with respect to the emission surface 11 and a length of 4 mm from the end of the second inclined surface 13b. The light is incident on the light guide plate 9 from the first incident end surface 10a and the second incident end surface on the light guide plate 9 because the third inclined surface 13c is inclined at an inclination angle of 2 °. 10b and the incident light from Specifically, the first light having directivity in which the peak of the emitted light intensity exists in the first direction and the second light having directivity in which the peak of the emitted light intensity exists in the second direction. It can be emitted as light.

  Therefore, the surface light source 8 is arranged on the side opposite to the observation side of the liquid crystal display panel 1 to constitute a liquid crystal display device, and image data for the left eye and right eye image to a plurality of pixels of the liquid crystal display panel 1 are formed. In synchronism with selective writing of image data, a first tilted in the direction opposite to the first incident end face 10a from the surface light source 8 with respect to the normal h of the exit surface 11 of the light guide plate 9. A first light having directivity in which a peak of the emitted light intensity exists in a direction, that is, a direction inclined by a predetermined angle in the direction of one of the left and right eyes of the display observer, and the light guide plate 9 In the second direction inclined in the direction opposite to the second incident end face 10b with respect to the normal line h of the exit surface 11, that is, in the direction inclined at a predetermined angle in the direction of the other eye of the observer. The liquid crystal display panel with the second light having directivity in which the peak of the radiant intensity exists By exiting toward the liquid crystal display panel 1, the left-eye image corresponding to the left-eye image data and the right-eye image corresponding to the right-eye image data are all displayed on the liquid crystal display panel 1. These pixels can be used for sequential display, and a display observer can observe a stereoscopic image.

  Therefore, according to the surface light source 8, it is possible to display a high-resolution stereoscopic image on the liquid crystal display device, and the surface light source 8 includes the light guide plate 9 and the first and second incident end surfaces 10a. , 10b, and the first and second light emitting elements 16a, 16b. The liquid crystal display device can be easily manufactured.

  Further, in this embodiment, the reflective surface 12 of the light guide plate 9 of the surface light source 8 has a length of 40 mm, excluding substantially 3 mm from the first and second incident end surfaces 10a and 10b. The plurality of horizontally elongated grooves 14 along the width direction of the light guide plate 9 are formed in parallel with each other at a predetermined pitch, and thus the first and second light beams having the directivity are emitted. The direction is close to the front direction of the surface light source 8 (the direction near the normal of the exit surface of the light guide plate 9), and the liquid crystal display device can observe a bright stereoscopic image.

  In the surface light source 8 of this embodiment, as described above, the refractive index of the light guide plate 9 is 1.49, the thickness of the central portion in the length direction of the light guide plate 9 is 2.1 mm, and the reflection surface 12 is The lengths of the three inclined surfaces 13a, 13b, and 13b forming the inclined surface portions 13 at both ends are 5 mm, 5 mm, and 4 mm, respectively, and the inclination angles of these inclined surfaces 13a, 13b, and 13b (relative to the emission surface 11 of the light guide plate 9). The angle) is 6 °, 4 °, and 2 °, respectively, and the angles of the two inclined surfaces of the plurality of horizontally long grooves 14 formed on the reflecting surface 12 (the angle of the exit surface 11 with respect to the normal h) are 50 °. Therefore, as shown in FIGS. 7 and 8, the first tilted from the exit surface 11 of the light guide plate 9 by approximately 10 ° in the direction opposite to the first incident end surface 10a with respect to the normal h. First direction of intensity distribution in which there is a peak of emitted light intensity in the direction And second directional light having an intensity distribution in which a peak of emitted light intensity exists in a second direction inclined by approximately 10 ° in a direction opposite to the second incident end face 10b with respect to the normal h. Can be emitted.

  FIG. 9 is an intensity distribution diagram of the first and second directional light emitted from the surface light source 8. In FIG. 9, the viewing angle on the horizontal axis is the observation angle of the emitted light in the length direction of the light guide plate 9 as viewed from the emission side of the surface light source 8 (observation side of the liquid crystal display panel 1). Is a direction opposite to the first incident end face 10a with respect to the normal h of the exit surface 11, and a negative viewing angle is opposite to the second incident end face 10b with respect to the normal h. Is the angle.

  Although omitted in FIGS. 7 and 8, the light incident on the light guide plate 9 from the first and second incident end faces 10 a and 10 b, reflected by the reflecting surface 12, and emitted from the emitting surface 11. Some of them are incident at a shallow incident angle (an angle within the total reflection critical angle) with respect to the interface between the exit surface 11 and the outside air, refracted greatly at the interface, and greatly with respect to the normal h of the exit surface 11. Some light exits in an inclined direction.

  Therefore, each of the first and second directional lights emitted from the surface light source 8 is inclined by approximately 10 ° with respect to the normal h of the emission surface 11 of the light guide plate 9 as shown in FIG. In addition to the direction, the light has an intensity distribution in which a certain peak of emitted light intensity exists in the direction near 50 ° to 60 ° with respect to the normal h, but the light exits in the direction near 50 ° to 60 °. Since the outgoing light in the oblique direction having the peak of the emitted light intensity is not observed by the display observer, the outgoing light in the oblique direction does not affect the display of the liquid crystal display device.

  Further, in the surface light source 8 of this embodiment, the exit surface 11 of the light guide plate 9 is a portion in the vicinity of the first and second incident end surfaces 10a and 10b (a portion having a length of 3 mm from each of the incident end surfaces 10a and 10b). And between the both ends of the emission surface 11 and the first and second incident end surfaces 10a and 10b, toward the incident end surfaces 10a and 10b, respectively, in the direction of the reflecting surface 12 of the light guide plate 9. Since the inclined surface 15 that is inclined and reflects the light incident from the incident end surfaces 10a and 10b toward the reflecting surface 12 is formed, the light guide plate 9 has the first and second incident end surfaces 10a and 10b. First light having directivity in which the peak of the emitted light intensity exists in the first direction (direction of about 10 ° with respect to the normal h of the emission surface 11) with each incident light efficiently. And the second direction (normal h of the exit surface 11) It can be emitted as a second light having a directivity in which a peak of emission intensity direction) of approximately -10 ° exists for.

  That is, since the light emitted from the first and second light emitting elements 16a and 16b is light that spreads radially around the light emitting point, the emission surface 11 of the light guide plate 9 extends to the incident end surfaces 10a and 10b. Then, of the light incident from the incident end faces 10a and 10b, the light directed to the vicinity of the incident end faces 10a and 10b of the exit surface 11 passes through the interface between the part and the outside air and becomes stray light. Exit.

  On the other hand, in this embodiment, the light exit surface 11 of the light guide plate 9 is formed excluding the portions near the first and second incident end surfaces 10a and 10b, and both ends of the light exit surface 11 and the first and second surfaces are formed. Since the inclined surfaces 15 are formed between the incident end surfaces 10a and 10b, the light emitted as the stray light is totally reflected by the interface between the inclined surface 15 and the outside air, and the light is transmitted to the light guide plate. 9 can be reflected from the reflecting surface 9 and emitted from the emitting surface 11 as the first and second directional light.

  As described above, the light exit surface 11 of the light guide plate 9 is formed by removing portions of a length of 3 mm from the first and second incident end surfaces 10a and 10b, and both ends of the light exit surface 11 and the Three portions forming the inclined surface portion 13 of the reflecting surface 12 of the light guide plate 9 in the portion between the first and second incident end surfaces 10a and 10b, that is, the portion extending 3 mm from the incident end surfaces 10a and 10b. Of the inclined surfaces 13a, 13b, 13c, the inclined surface 15 is inclined (inclined in the opposite direction to the first inclined surface 13a at the same inclination angle of 6 ° as the first inclined surface 13a on the incident end surface 10a, 10b side. In this way, most of the light incident on the light guide plate 9 from the first and second incident end faces 10a and 10b and reflected by the inclined surface 15 is made to be in the first direction. The peak of the emitted light intensity Can be emitted first and light having a directivity present, as a second light having a directivity peak of emission intensity in the second direction are present.

  The surface light source 8 faces the side opposite to the observation side of the liquid crystal display panel 1 and faces the exit surface 11 of the light guide plate 9 in parallel to the incident surface of the liquid crystal display panel 1 (the outer surface of the incident side polarizing plate 4). The light guide plate 9 is arranged such that the length direction of the light guide plate 9 is substantially parallel to the left-right direction of the display area A of the liquid crystal display panel 1.

  In this embodiment, the surface light source 8 is directed to the right side when the arrangement side of the first light emitting element 16a is viewed from the observation side (upper side in FIGS. 1 and 2) of the liquid crystal display panel 1, and the second light emitting element is arranged. 16b is disposed toward the left side when viewed from the observation side, and the light from the first light emitting element 16a is emitted from the light exit surface of the light guide plate 9 in the direction of the left eye of the display observer. The light is emitted as first directional light having directivity in which a peak exists, and light emitted from the second light emitting element 16b is emitted from the light emitting surface of the light guide plate 9 toward the right eye of the display observer. It is made to radiate | emit as 2nd directivity light with the directivity in which this peak exists.

  Hereinafter, of the first and second light emitting elements 16a and 16b of the surface light source 8, the first light emitting element 16a on the right side (left side in FIGS. 1 and 2) as viewed from the observation side of the liquid crystal display panel 1 is referred to. The left-eye light-emitting element is referred to as a left-eye light-emitting element, and the second light-emitting element 16b on the left side (right side in FIGS. 1 and 2) viewed from the observation side is referred to as a right-eye light-emitting element.

  The display area A of the liquid crystal display panel 1 has an area that is slightly smaller than the area of the exit surface 11 of the light guide plate 9 of the surface light source 8, and therefore the entire area of the exit surface 11 of the light guide plate 9. The first and second directional light emitted from the light enters the entire display area A of the liquid crystal display panel 1.

  On the other hand, of the first and second directional diffusers 17 and 18 disposed between the liquid crystal display panel 1 and the surface light source 8, the first directional diffuser 17 is the left of the surface light source 8. First directional light emitted from the light emitting element for eye 16a and incident on the light guide plate 9 from the first incident end face 10a and emitted from the output surface 11 of the light guide plate 9, that is, the normal line of the output surface 11 Diffusion characteristics with respect to light having directivity (hereinafter referred to as left-eye illumination light) in which the peak of the emitted light intensity exists in a direction inclined by approximately 10 ° in the direction of the left eye of the display observer with respect to h The second directional diffuser plate 18 is emitted from the light emitting element 16b for the right eye of the surface light source 8 and enters the light guide plate 9 from the second incident end surface 10a. Display observer with respect to the second directional light emitted from the emission surface 11, that is, the normal h of the emission surface 11. Light peak of the emitted light intensity to approximately 10 ° inclined to the direction of the right eye with a directivity present a diffuser having a diffusion characteristic with respect to (hereinafter, right eye say illumination light).

  FIG. 10 shows the diffusion of the first directional diffuser plate (hereinafter referred to as the left-eye directional diffuser plate) 17 and the second directional diffuser plate (hereinafter referred to as the right-eye directional diffuser plate) 18. FIG. In FIG. 10, the viewing angle on the horizontal axis is the observation angle of diffused light in the left-right direction of the display area A of the liquid crystal display panel 1, and the positive viewing angle is the normal line (surface light source) of the diffusion plates 17 and 18. The angle of the left eye direction of the display observer and the negative viewing angle with respect to the normal line h of the output surface 11 of the light guide plate 9 and the normal line of the liquid crystal display panel 1 are This is the angle of the observer's right eye direction.

  As shown in FIG. 10, the left-eye directional diffuser 17 transmits the right-eye illumination light out of the left-eye illumination light and right-eye illumination light emitted from the surface light source 8 with little diffusion. The right-eye illumination light is diffused and emitted to the liquid crystal display panel 1 side, and the right-eye directional diffuser 18 transmits the left-eye illumination light and the right-eye illumination light emitted from the surface light source 8. Among them, the left-eye illumination light is transmitted without being diffused, and the right-eye illumination light is diffused and emitted to the liquid crystal display panel 1 side.

  The diffusion start angle of the left-eye directional diffuser plate 17 and the right-eye directional diffuser plate 18 (the angle with respect to the normal of the diffuser plates 17 and 18) is the left emitted from the surface light source 8 as shown in FIG. The angle is set around 10 ° in accordance with the angle in the direction in which the intensity peaks of the eye illumination light and the right eye illumination light exist.

  The left-eye directional diffuser plate 17 and the right-eye directional diffuser plate 18 are laminated with each other, and one of the directional diffuser plates, for example, the left-eye directional diffuser plate 17 is attached to the liquid crystal display panel 1. The other directional diffuser plate, for example, the right-eye directional diffuser plate 18, is brought into contact with or close to the incident surface (the outer surface of the incident-side polarizing plate 4) on the output surface 11 of the light guide plate 9 of the surface light source 8. An air layer is secured between the light emitting surface 11 and the light emitting surface 11 so as to face each other.

  Next, the control means 19 for driving the liquid crystal display panel 1 and the surface light source 8 will be described. Although the specific configuration of the control means 19 is not shown, the gate side driver 6 of the liquid crystal display panel 1 and The writing control circuit controls the data-side driver 7 and the illumination control circuit controls the emission of light from the left-eye light-emitting element 16a and the right-eye light-emitting element 16b of the surface light source 8.

  The control means 19 sequentially writes image data for the left eye and image data for the right eye for observation with the left and right eyes to each pixel of the liquid crystal display panel 1, and the first and second of the surface light source 8. Of the first light emitting elements 16a and 16b, the right first light emitting element as viewed from the viewing side of the liquid crystal display panel 1, that is, the left eye light emitting element 16a is synchronized with the writing of the left eye image data. Is emitted in synchronization with the writing of the right-eye image data from the second light-emitting element on the left side as viewed from the observation side, that is, the right-eye light-emitting element 16b.

  In this embodiment, the surface light source 8 is provided with light emitting elements that selectively emit light of three colors of red, green, and blue as the first and second light emitting elements 16a and 16b, and the control means 19 Are displayed in one frame for displaying one stereoscopic image, red, green and blue unit color image data for displaying a left-eye image and red for displaying a right-eye image. , Green and blue unit color image data are selected in an arbitrary order and sequentially written to each pixel of the liquid crystal display panel 1, and the first and second light emitting elements 16a and 16b of the surface light source 8 are selected. The left-eye light-emitting element 16a viewed from the viewing side of the liquid crystal display panel 1 emits red, green, and blue light of the three colors red, green, and blue for displaying the left-eye image. For the right eye on the left side as seen from the observation side The light elements 16b emit the light of the three colors red, green, and blue in synchronization with the writing of the unit color image data of the three colors red, green, and blue for displaying the right-eye image. It is configured.

  The light emitting elements 16a and 16b for the left eye and right eye of the surface light source 8 are not shown in their internal structure, but a red LED (light emitting diode) that emits red light, a green LED that emits green light, and blue light. A solid state light emitting device including a blue LED that emits light, and selectively driving light of three colors of red, green, and blue toward the incident end faces 10a and 10b of the light guide plate 9 by selectively driving these LEDs. To exit.

  The light emitting elements for the left eye and the right eye may be three cold cathode tubes that respectively emit red, green, and blue light.

  The unit color image data of three colors red, green, and blue for displaying the left eye image and the unit color image data of three colors red, green, and blue for displaying the right eye image are: For example, image data of each color component of red, green, and blue by a left lens of a color image captured by a digital camera having two left and right imaging lenses arranged at predetermined intervals, and red, green, and blue by a right lens The image data of each color component.

  In this liquid crystal display device, unit color image data of three colors red, green, and blue for displaying an image for the left eye is displayed by the control means 19 during one frame for displaying one stereoscopic image. Unit color image data of three colors red, green, and blue for displaying an image for the right eye is selected in an arbitrary order and sequentially written to each pixel of the liquid crystal display panel 1, and the surface light source is controlled by the control means 19 8 controls the lighting of the left-eye and right-eye light-emitting elements 16a and 16b, and the color and direction corresponding to the unit color image data written to each pixel of the liquid crystal display panel 1 from the surface light source 8. By emitting the illumination light having the characteristic from the surface light source 1 in synchronization with the writing of the unit color image data, the red image for the left eye, the green image, the blue image, and the right 6 in total, red, green and blue images for eyes Sequentially displayed unit color images in a predetermined order.

  That is, this liquid crystal display device forms one frame for displaying one stereoscopic image with six fields, and for each field, a red image for the left eye, a green image for the left eye, a blue image for the left eye, Field sequential display is performed for sequentially displaying one of six unit color images of a right-eye red image, a right-eye green image, and a right-eye blue image in an arbitrary order. The six unit color images can be displayed using all the pixels of the liquid crystal display panel, and a three-dimensional color image in which the six unit color images appear to overlap can be observed. An image can be displayed.

  In this liquid crystal display device, it is preferable to set the 1 frame to 1/30 seconds or less and the 1 field to 1/180 seconds or less. An image can be displayed.

  In addition, the liquid crystal display device can be easily manufactured because the configuration of the surface light source 8 is simple as described above.

  Further, the liquid crystal display device has a left-eye directional diffuser plate 17 having diffusion characteristics with respect to left-eye illumination light emitted from the surface light source 8 between the liquid crystal display panel 1 and the surface light source 8. And a right-eye directional diffuser plate 18 having a diffusion characteristic with respect to the right-eye illumination light emitted from the surface light source 8, and thus higher quality without glare and uneven brightness. 3D color images can be displayed.

  The liquid crystal display device can display not only a stereoscopic color image but also a planar image in a field sequential manner. In this case, red, green, and blue unit color image data for either one of the left and right eyes is used. Or red, green, and blue unit color image data captured by one imaging lens are sequentially written to each pixel of the liquid crystal display panel 1, and the unit colors written are synchronized with the writing of the unit color image data. The illumination light for the left eye and the right eye corresponding to the image data may be emitted from the surface light source 8 at the same time.

  Further, the liquid crystal display device of the above embodiment uses the liquid crystal display panel 1 that does not include a color filter, and selectively emits light of three colors of red, green, and blue to the surface light source 8 for the left eye and the right eye. By providing the light emitting elements 16a and 16b for use, a stereoscopic color image is displayed by field sequential display. However, the present invention provides a liquid crystal display panel with a plurality of colors corresponding to the plurality of pixels, for example, red, The present invention can also be applied to a liquid crystal display device that includes three color filters of green and blue and includes a light emitting element for left eye and right eye that emits white light to the surface light source 8. The left-eye image data and the right-eye image data are sequentially written to each pixel of the liquid crystal display panel, and light is emitted from the left-eye light emitting element of the surface light source in synchronization with the writing of the left-eye image data. Is emitted The left eye color image and the right eye color image are alternately displayed sequentially by emitting light from the right eye light emitting element in synchronization with the writing of the right eye image data. What is necessary is just to make it observe the three-dimensional image which an image appears to overlap.

  Further, in the above embodiment, the surface light source 8 is arranged so that the direction in which the intensity peaks of the left-eye illumination light and the right-eye illumination light exist is approximately 10 ° with respect to the normal h of the exit surface 11 of the light guide plate 9. The direction in which the intensity peaks of the left-eye illumination light and the right-eye illumination light exist is designed according to the viewing distance of the display depending on the use of the liquid crystal display device. The direction in which the intensity peaks of the left-eye illumination light and the right-eye illumination light exist may be set so as to coincide with the direction toward the left and right eyes of the display observer, and the length of the light guide plate 9 is adjusted accordingly. What is necessary is just to set the plate | board thickness of the center part of a length direction, and the length and inclination | tilt angle of several inclined surface 13a, 13b, 13c which form the inclined surface part 13 of the both ends side of the reflective surface 12 of the said light-guide plate 9. FIG.

  Moreover, in the said Example, although the inclined surface part 13 of the both ends side of the reflective surface 12 of the light-guide plate 9 of the said surface light source 8 is formed by the three inclined surfaces 13a, 13b, 13c, two inclined surface parts 13 are formed. You may form with the above several inclined surface, In that case, the inclination angle (angle with respect to the output surface 11 of the light-guide plate 9) of each of these inclined surfaces is the center part side of the length direction of the light-guide plate 9, respectively. The light is emitted from the first light emitting element 10a and incident on the light guide plate 9 from the first incident end face 10a by sequentially setting a steep angle from the inclined face toward the inclined face on the incident end face 10a, 10b side. And the light emitted from the second light emitting element 10b and incident on the light guide plate 9 from the second incident end face 10b, respectively, with the inclined surface portions 13 formed on both ends of the reflection surface 12 of the light guide plate 9, and The central portion of the reflecting surface 12 in the length direction The light that is more reflected and incident from the first incident end face 10a is inclined at a predetermined angle in the direction opposite to the first incident end face 10a with respect to the normal line h from the outgoing face 11 of the light guide plate 9. The first light having the directivity in which the peak of the emitted light intensity exists in the first direction is emitted, and the light incident from the second incident end surface 10b is transmitted from the output surface 11 of the light guide plate 9 to the first light. Output as a second light having directivity in which a peak of the emitted light intensity exists in a second direction inclined at a predetermined angle in a direction opposite to the second incident end face 10b with respect to the normal h. Can do.

1 is an exploded perspective view of a liquid crystal display device showing an embodiment of the present invention. The side view of the said liquid crystal display device. The side view of the light-guide plate of the surface light source in the said liquid crystal display device. An enlarged side surface on one end side of the light guide plate. The enlarged view of the V section of FIG. The enlarged view of the VI section of FIG. The figure which shows the emission state of the 1st light from the said surface light source. The figure which shows the emission state of the 2nd light from the said surface light source. The intensity distribution diagram of the 1st and 2nd light radiate | emitted from the said surface light source. The diffusion characteristic figure of the 1st and 2nd directional diffusion plate of the said liquid crystal display device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display panel, A ... Display area, 8 ... Surface light source, 9 ... Light guide plate, 10a, 10b ... Incident end surface, 11 ... Output surface, 12 ... Reflecting surface, 13 ... Inclined surface part, 13a, 13b, 13c ... Inclination Surface, 14 ... Horizontally long groove part, 15 ... Inclined surface, 16a, 16b ... Light emitting element, 17, 18 ... Directional diffuser plate, 19 ... Control means.

Claims (15)

A light guide plate made of a plate-shaped transparent member and having a predetermined thickness between one plate surface and the other plate surface ;
A first light emitting element that emits light toward the first end face of the light guide plate;
A second light emitting element that emits light toward the second end face of the light guide plate facing the first end face,
The light guide plate has a first parallel region in which a predetermined region of the one plate surface is formed in parallel to a plane perpendicular to the first end surface or the second end surface,
The light guide plate in the first parallel region is
A second parallel region formed so that the other plate surface is parallel to the one plate surface ;
It is formed on the first end face side with respect to the second parallel region, and the thickness on the first end face side is larger than the thickness on the second parallel region according to the distance from the second parallel region. A first sloping region that becomes thinner;
It is formed on the second end surface side from the second parallel region, and the thickness on the second end surface side is larger than the thickness on the second parallel region according to the distance from the second parallel region. A second inclined region that becomes thinner;
Have
In the second parallel region, the first inclined region, and the second inclined region, a plurality of grooves extending in a direction along the first end surface or the second end surface are formed on the other plate surface , respectively. A surface light source characterized by that.   2. The surface light source according to claim 1, wherein each of the grooves has a V-shaped cross section.   The two sides of the groove centered on the apex angle of the groove having a V-shaped cross-sectional shape are formed at angles symmetrical to each other with respect to the normal to the plane. 2. A surface light source according to 2.   4. The surface light source according to claim 1, wherein the grooves are arranged at a predetermined pitch over the entire area of the first parallel region. 5. The first inclined region may be any of claims 1 to 4, characterized in that the inclination angle of said other plate surface is different for the one plate surface according to the distance from the second parallel region The surface light source described in 1.   6. The surface light source according to claim 5, wherein in the first inclined region, the inclination angle is formed such that the first end surface side is larger than the second parallel region side. The said 2nd inclination area | region differs in the inclination angle of said other board surface with respect to said one board surface according to the distance from said 2nd parallel area | region. The surface light source described in 1.   8. The surface light source according to claim 7, wherein in the second inclined region, the inclination angle is formed such that the second end surface side is larger than the second parallel region side.   9. The surface light source according to claim 1, wherein the first inclined region and the second inclined region are formed in symmetrical shapes. A light guide plate made of a plate-shaped transparent member and having a predetermined thickness between one plate surface and the other plate surface ;
A first light emitting element that emits light toward the first end face of the light guide plate;
A second light emitting element that emits light toward a second end face of the light guide plate facing the first end face;
A liquid crystal display panel disposed on the one plate surface side of the light guide plate and having a plurality of display pixels formed in a predetermined display area,
The light guide plate has a first parallel region in which a predetermined region of the one plate surface is formed in parallel to a plane perpendicular to the first end surface or the second end surface,
The light guide plate in the first parallel region is
A second parallel region formed so that the other plate surface is parallel to the one plate surface ;
It is formed on the first end face side with respect to the second parallel region, and the thickness on the first end face side is larger than the thickness on the second parallel region according to the distance from the second parallel region. A first sloping region that becomes thinner;
It is formed on the second end surface side from the second parallel region, and the thickness on the second end surface side is larger than the thickness on the second parallel region according to the distance from the second parallel region. A second inclined region that becomes thinner,
In the second parallel region, the first inclined region, and the second inclined region, a plurality of grooves extending in a direction along the first end surface or the second end surface are formed on the other plate surface , respectively. A liquid crystal display device. 11. The liquid crystal according to claim 10, wherein light from the first light-emitting element or the second light-emitting element is irradiated from the one plate surface in the first parallel region toward the display area. Display device. A display control section for selectively switching and displaying the left-eye image and the right-eye image on the liquid crystal display panel;
A first lighting state in which the first light emitting element is set to a light emitting state and the second light emitting element is set to a non-light emitting state, and the second light emitting element is set to a non-light emitting state and the second light emitting element is set to The lighting control part which switches the 2nd lighting state made into a light emission state synchronizing with the display switching timing of the said image for left eyes, and the image for right eyes is provided, The lighting control part characterized by the above-mentioned. Liquid crystal display device. The left eye image and the right eye image are respectively composed of a red component image, a green component image, and a blue component image,
The liquid crystal display device according to claim 12, wherein the display control unit selectively switches the color component images to be displayed on the liquid crystal display panel. The first light emitting element and the second light emitting element emit red light, green light and blue light, respectively.
The lighting control unit causes the first light emitting element or the second light emitting element to emit light having a color corresponding to a color component of an image displayed on the liquid crystal display panel. A liquid crystal display device according to 1. Between the light guide plate and the liquid crystal display panel,
Higher than the diffusion degree for light diffusing degree against light coming emitted from the through the one plate surface first light emitting element comes emitted from the second light emitting element via the one plate surface A diffusion degree of light emitted from the second light emitting element through the first diffusion plate and the one plate surface is emitted from the first light emitting device through the one plate surface. The liquid crystal display device according to claim 10, further comprising a second diffusion plate having a higher degree of diffusion with respect to light.

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