JP4648338B2 - Liquid crystal display device - Google Patents

Description

  The present invention relates to a liquid crystal display device for a mobile product such as a mobile phone using a flat illumination device that can emit light from both the front and back surfaces of a light guide plate using a prism sheet or a diffusion sheet.

  Conventionally, when a liquid crystal display device displays in both the front surface direction and the back surface direction, for example, in a mobile product such as a mobile phone, when performing a liquid crystal display of a main screen and a liquid crystal display of a sub screen on the back side of a case, etc. It was the structure which was able to observe from the front and back using two liquid crystal display devices incorporating the.

  In addition, a conventional backlight is used for the liquid crystal display on the main screen, and a transmissive liquid crystal such as a clear and bright TFT liquid crystal is used. On the sub-screen, a reflector is provided on the back surface of the backlight to provide a reflective liquid crystal. There was a thing of the composition which made it possible to observe from two sides of the front and back.

  As described above, when displaying on the liquid crystal display device in both the front surface direction and the back surface direction in the related art, for example, in a mobile product such as a mobile phone, when performing the liquid crystal display of the main screen and the liquid crystal display of the sub screen on the back side of the case In the configuration in which two liquid crystal display devices incorporating a flat illumination device are used so that observation can be performed from the front and back surfaces, two sets of backlights are required, and a light guide plate that occupies a large proportion of the backlight configuration. Two sets of light sources are required as well as two sets.

  In addition, a light guide plate used as a liquid crystal display device of a mobile product (for example, a mobile phone) becomes a big factor in weight and thickness, and there is a problem in lightening and downsizing (thickness) of the mobile product. .

  In addition, since two sets of light sources are required, power consumption increases, battery life is shortened, and if the amount of batteries is increased to secure power, the size, weight, and economics can be reduced. There are challenges.

  In addition, when a liquid crystal display device is provided on both the front and back surfaces, a conventional backlight is used for the liquid crystal display on the main screen, a transparent liquid crystal such as a bright and bright TFT liquid crystal is used, and a back screen is used for the sub screen. An object having a structure in which a reflector or the like is provided on the back surface of the light and the reflection type liquid crystal is used so that the light can be observed from the front and back surfaces can be sufficiently satisfied with respect to light weight and downsizing. However, since a reflective liquid crystal is used for the sub-screen, there are problems that the luminance is low and the color is not clear in the case of a color image.

The present invention has been made to solve the above-described problems, and includes a front surface portion and a back surface portion provided between two liquid crystal panels, a main liquid crystal panel and a sub liquid crystal panel smaller than the main liquid crystal panel. A liquid crystal display device comprising a light guide plate that emits light from both sides, wherein a partial colored sheet having an opening part is provided between the light guide plate facing the sub liquid crystal panel to improve the contrast. The object is to provide a liquid crystal display device having two screens.

In order to solve the above problems, a liquid crystal display device according to claim 1 of the present invention includes a main liquid crystal panel, a sub liquid crystal panel smaller than the main liquid crystal panel, and a surface provided between the main liquid crystal panel and the sub liquid crystal panel. the light guide plate is emitted from both the parts and the bottom a liquid crystal display device which have a at least a planar lighting device,
A case having an opening window slightly opposite to the sub liquid crystal panel facing the sub liquid crystal panel is provided, and a partially colored sheet having an opening slightly smaller than the size of the opening window is provided on the opening window and the sub liquid crystal panel. It is provided between the facing case and the light guide plate .

The liquid crystal display device according to claim 1 emits light from both a main liquid crystal panel, a sub liquid crystal panel smaller than the main liquid crystal panel, and a front surface portion and a back surface portion provided between the main liquid crystal panel and the sub liquid crystal panel. the light guide plate which possess at least a planar lighting device, provided with a casing having a slightly smaller opening window than opposing sub LCD panel to the sub-liquid crystal panel, having a slightly smaller opening than the size of the opening window Since the partial partially colored sheet is provided between the opening window and the case facing the sub liquid crystal panel and the light guide plate, the contrast of the sub liquid crystal panel can be improved.
Further, only the light required for the sub liquid crystal panel can be emitted, and other light can be shielded. Further, the contrast of the sub liquid crystal panel can be improved, and when it is made particularly small, the scattered light generated at the end of a reflective case or the like can be shielded without returning.
Furthermore, when white is used as the color of the reflector, the contrast between the reflector and the opening can be reduced.

Furthermore, the liquid crystal display device according to claim 2 is characterized in that the partially colored sheet is colored in a dark color system and has a film shape.

In the liquid crystal display device according to the second aspect , since the partially colored sheet is colored in a dark color system and is in a film form, the contrast of the sub liquid crystal panel can be improved.

Furthermore, the liquid crystal display device according to claim 3 is provided with a light deflecting element on the front surface portion and / or the back surface portion of the light guide plate, and is totally reflected or / and refracted, and is emitted from both the own surface and the opposing surface. It is characterized by.

The liquid crystal display device according to claim 3 is provided with a light deflection element on the front surface portion and / or the back surface portion of the light guide plate, and is totally reflected or / and refracted, and is emitted from both the own surface and the opposite surface. And can be emitted from both sides.

Furthermore, the liquid crystal display device according to a fourth aspect is characterized in that a prism sheet or / and a diffusion sheet or / and a polarization reflection sheet are provided on the front surface portion and / or back surface portion side of the light guide plate of the flat illumination device.

In the liquid crystal display device according to the fourth aspect , since the prism sheet or / and the diffusion sheet or / and the polarization reflection sheet are provided on the surface portion or / and the back surface side of the light guide plate of the flat illumination device, the surface portion of the light guide plate By refracting the light beam having a large emission angle from the back surface portion by the prism sheet, the emitted light can be obtained from both surfaces of the light guide plate at a time.
Moreover, since the light emitted by total reflection is emitted to both sides of the light guide plate by the diffusion sheet and the pair of prism sheets, only the surface on which the light deflection element is provided using a directional light source or light beam. The emitted light can be obtained from both sides of the light guide plate at one time.
Furthermore, since the light emitted by the total reflection by the prism sheet and the diffusion sheet is emitted to both sides of the light guide plate, only once on the surface where the light deflection element is provided using a directional light source or light beam. In addition, the emitted light can be obtained from both sides of the light guide plate.
In addition, if a polarizing reflection sheet is provided, the visibility of the liquid crystal panel or the liquid crystal cell when high luminance is required can be further improved.

The liquid crystal display device according to claim 5 is characterized in that a reflector having an opening hole facing the sub liquid crystal panel is provided on one side of the light guide plate of the flat illumination device.

In the liquid crystal display device according to the fifth aspect , the reflector having the opening hole facing the sub liquid crystal panel is provided on one side of the light guide plate of the flat illumination device. The leaked light can be returned to the light guide plate again, and plane emission light having a size suitable for the purpose can be obtained.

Furthermore, in the liquid crystal display device according to claim 6 , the light deflection element is a true arc, an elliptical arc, a cone, a cylinder, a polygonal pyramid, a polygonal column, and a continuous or non-continuous cross section having an arc shape, a polygonal pillow shape. It is characterized by being provided at random or concentric positions on the front surface portion and / or the back surface portion of the light guide plate.

In the liquid crystal display device according to claim 6 , the light deflection element is a true arc, an elliptical arc, a cone, a cylinder, a polygonal pyramid, a polygonal column, and a continuous or non-continuous cross section having an arc shape or a polygonal pillow shape. These projections or recesses are provided at random or concentric positions on the front and / or back of the light guide plate, so that light with a large exit angle and light with a small exit angle are emitted from the front and back portions of the light guide plate. can do.

The liquid crystal display device according to claim 7 is characterized in that the prism sheet has a substantially triangular cross section or at least one inclined surface, and has a straight shape or a concentric arc shape on the prism sheet surface. .

In the liquid crystal display device according to claim 7 , the prism sheet has a substantially triangular shape or at least one inclined surface, and has a straight shape or a concentric arc shape on the prism sheet surface. A light beam having a large emission angle is emitted in a direction substantially perpendicular to the front surface portion and / or the back surface portion by the prism sheet. Thereby, the emitted light can be obtained from the entire front surface with respect to the observation side.

As described above, the liquid crystal display device according to claim 1 includes a main liquid crystal panel, a sub liquid crystal panel smaller than the main liquid crystal panel, and a front surface portion and a back surface portion provided between the main liquid crystal panel and the sub liquid crystal panel. possess at least a planar illumination device light guide plate is emitted from both the, provided with a casing having a slightly smaller opening window than opposing sub LCD panel to the sub-LCD panel, it is slightly smaller than the size of the opening window Since the partial partially colored sheet having the opening is provided between the opening window and the case facing the sub liquid crystal panel and the light guide plate, the contrast of the sub liquid crystal panel can be improved.
Further, only the light required for the sub liquid crystal panel can be emitted, and other light can be shielded. Further, the contrast of the sub liquid crystal panel can be improved, and when it is made particularly small, the scattered light generated at the end of a reflective case or the like can be shielded without returning.
Furthermore, when white is used as the color of the reflector, the contrast between the reflector and the opening can be reduced.
Therefore, the visual recognition of the sub screen through the opening of the reflector can be suppressed.

In the liquid crystal display device according to the second aspect , since the partially colored sheet is colored in a dark color system and is in the form of a film, the contrast of the sub liquid crystal panel can be improved. Therefore, it is possible to recognize bright and easy-to-see images and characters.

The liquid crystal display device according to claim 3 is provided with a light deflection element on the front surface portion and / or the back surface portion of the light guide plate, and is totally reflected or / and refracted, and is emitted from both the own surface and the opposite surface. And can be emitted from both sides.
Therefore, it is possible to obtain a plane light of a desired size from both the front and back sides, and to reduce the thickness as a plane illumination of a liquid crystal display device composed of two main and sub screens, and with one light source. Two flat illuminations can be obtained, and it is excellent in small size, thin economy.

In the liquid crystal display device according to the fourth aspect , since the prism sheet or / and the diffusion sheet or / and the polarization reflection sheet are provided on the surface portion or / and the back surface side of the light guide plate of the flat illumination device, the surface portion of the light guide plate By refracting the light beam having a large emission angle from the back surface portion by the prism sheet, the emitted light can be obtained from both surfaces of the light guide plate at a time.
Moreover, since the light emitted by total reflection is emitted to both sides of the light guide plate by the diffusion sheet and the pair of prism sheets, only the surface on which the light deflection element is provided using a directional light source or light beam. The emitted light can be obtained from both sides of the light guide plate at one time.
Furthermore, since the light emitted by the total reflection by the prism sheet and the diffusion sheet is emitted to both sides of the light guide plate, only once on the surface where the light deflection element is provided using a directional light source or light beam. In addition, the emitted light can be obtained from both sides of the light guide plate.
Therefore, it is easy to see and can improve the operability for the user, prevent misrecognition, and improve the convenience.
In addition, if a polarizing reflection sheet is provided, the visibility of the liquid crystal panel or the liquid crystal cell when high luminance is required can be further improved.
For this reason, since natural light and S wave components other than the P wave component are reflected to the light guide plate side, this reflected light component can be used as an increase in luminance on the main screen side.

In the liquid crystal display device according to the fifth aspect , the reflector having the opening hole facing the sub liquid crystal panel is provided on one side of the light guide plate of the flat illumination device. The leaked light can be returned to the light guide plate again, and plane emission light having a size suitable for the purpose can be obtained.
Therefore, plane emission light having a size suitable for the purpose can be emitted to two liquid crystal panels or liquid crystal cells. As a result, the size of the screen such as the sub-screen can be designed freely, and the versatility is high.

In the liquid crystal display device according to claim 6 , the light deflection element is a true arc, an elliptical arc, a cone, a cylinder, a polygonal pyramid, a polygonal column, and a continuous or non-continuous cross section having an arc shape or a polygonal pillow shape. These projections or recesses are provided at random or concentric positions on the front and / or back of the light guide plate, so that light with a large exit angle and light with a small exit angle are emitted from the front and back portions of the light guide plate. can do.
Therefore, the number of light sources, the positions to be provided, and the size of the liquid crystal display device can be freely designed without being limited.

In the liquid crystal display device according to claim 7 , the prism sheet has a substantially triangular shape or at least one inclined surface, and has a straight shape or a concentric arc shape on the prism sheet surface. A light beam having a large emission angle is emitted in a direction substantially perpendicular to the front surface portion and / or the back surface portion by the prism sheet. Thereby, the emitted light can be obtained from the entire front surface with respect to the observation side.
Therefore, it is possible to recognize bright and easy-to-see images and characters.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
In the present invention, light deflecting elements are provided on the front and back surfaces of a light guide plate provided between two liquid crystal panels, ie, a main liquid crystal panel and a sub liquid crystal panel smaller than the main liquid crystal panel. A liquid crystal display device comprising a light guide plate that emits light from both the part and a partially partially colored sheet having an opening slightly smaller than the size of the opening window of the case, facing the opening window and the sub liquid crystal panel An object of the present invention is to provide a thin liquid crystal display device having two main screens, which is provided between a case and a light guide plate and can improve contrast, and has an energy saving effect.

FIG. 1A is a schematic perspective view of a liquid crystal display device according to the present invention in which a flat illumination device that emits light from both sides is arranged between two liquid crystal panels or liquid crystal cells. FIG. 2A is a front perspective view of a foldable mobile phone, FIG. 2B is a rear perspective view of the foldable mobile phone, and FIG. 3 is a liquid crystal display device according to the present invention. FIG. 4 is a schematic side sectional view showing an example in which a main liquid crystal display device and a sub liquid crystal display device are provided on both sides of one flat illumination device, and FIG. 4 shows an example of the flat illumination device according to the present invention. FIG. 5 to FIG. 7 are partially enlarged side sectional views showing other examples of the flat lighting device according to the present invention, and FIG. 8 is a schematic perspective view showing still another example of the flat lighting device according to the present invention. 9 and 9 show the positions of the light deflection element and the light source formed on the light guide plate of the flat illumination device according to the present invention. FIG. 10 is a plan view of another example showing the positional relationship between the light deflection element and the light source formed on the light guide plate of the flat illumination device according to the present invention, and FIG. 11 is a BB line in FIG. FIG. 12 is a partial sectional view taken along line aa in FIG. 10, FIG. 12 is a schematic sectional side view showing another embodiment of the liquid crystal display device including the flat illumination device according to the present invention, and FIGS. diagram for explaining an effect of the opening of the partially colored sheet, FIG. 14 (a), (b) are diagrams for explaining the effect of the presence of partially colored sheet, FIG. 15 is a plan according to the present invention FIG. 16 is an exploded perspective view of a flat illumination device in the liquid crystal display device of FIG. 15. FIG. 16 is a schematic side sectional view showing still another embodiment of the liquid crystal display device including the illumination device.

  FIGS. 1A and 1B and FIGS. 2A and 2B show a mobile phone as an example of a mobile product including a liquid crystal display device using a flat illumination device according to the present invention.

  The mobile phone 2 stores various components in a front surface side case 3 and a back surface side case 4. The front case 3 is provided with a main screen 5 for displaying various push buttons such as numbers and various information as a telephone. The main screen 5 includes a main liquid crystal panel, a liquid crystal cell, and the like (not shown), and a backlight light guide plate is provided below the main screen 5.

  Further, the back case 4 is provided with a sub-screen 6 for displaying various information such as time and the telephone number of the other party at the time of incoming call. The sub screen 6 has a sub liquid crystal panel, a liquid crystal cell, and the like (not shown), and a light guide plate of a backlight is provided below the sub screen 6.

  The light guide plate used for the backlights of the main and sub liquid crystal panels and liquid crystal cells is composed of a single-sided or single-sided light guide plate.

  Hereinafter, the configuration of the liquid crystal display device 1 including the flat illumination device according to the present invention that is employed in mobile products such as the mobile phone 2 will be described.

As shown in FIG. 3, the liquid crystal display device 1 includes a light source 11 that supplies light to the light guide plate 7, and light that is present inside the light guide plate 7 by the light source 11 is emitted to both surfaces of the front surface portion 8 and the back surface portion 9. In order to achieve this, a light guide plate 7 provided with light deflecting elements 71 made of convex or concave prisms or dots on the front surface portion 8 and the back surface portion 9 respectively, and the front surface portion 8 and the back surface portion 9 of the light guide plate 7 The upper portion includes a prism sheet 12 for emitting light emitted from the front surface portion 8 and the back surface portion 9 substantially vertically, a diffusion sheet 13 for diffusing the emitted light uniformly, and the like. a planar lighting device comprising emitting area of the light emitted from the reflector 14 having an opening hole 14a partially to control 9, the liquid crystal on the upper position of the surface portion 8 and the rear surface portion 9 and the reflector 14 Panel 5, liquid crystal cell 5, liquid crystal panel 6, and liquid crystal cell Configured to include a.

  The light guide plate 7 is formed in a substantially rectangular shape using transparent acrylic resin (PMMA), polycarbonate (PC), or the like. The light guide plate 7 has at least one side surface portion as the incident portion 10 and has the light deflection element 71 on the front surface portion 8 and / or the back surface portion 9 (the front surface portion 8 and the back surface portion 9 in the example of FIG. 3). .

  Further, the arrangement, distribution, and shape of the light deflection element 71 provided on the light guide plate 7 are determined according to the purpose, as shown in FIGS.

Here, for example, when the material of the light guide plate 7 is polycarbonate (PC) resin, the refractive index n of the polycarbonate resin is 1.59. Accordingly, the light beam that has entered the light guide plate 7 from the incident portion 10 through the air layer has a relationship of 0 ≦ | α | ≦ sin ⁻¹ (1 / n) (where n is an air layer and the refractive index n = 1). From the equation, the light is present in the light guide plate 7 as light having a substantially refraction angle α = ± 38.997 °.

  Further, the light incident on the light guide plate 7 within the range of the refraction angle α = ± 38.997 ° is sin γ = (1 / n at the boundary surface between the light guide plate 7 and the air layer (refractive index n = 1). ) Can be used to express the critical angle. For example, since the refractive index of polycarbonate resin, which is a resin material used for a general light guide plate 7, is about n = 1.59, the critical angle γ is about γ = 38.97 °. In the case of a light guide plate using an acrylic resin (PMMA) material, the refractive index n of the acrylic resin is about n = 1.49 and the refraction angle α is about α = 42.38 °. The angle γ is also about γ = 42.38 °.

  As a flat illumination device used in the liquid crystal display device 1 of this example, as shown in FIG. 4, convex or concave light deflection elements 71 are formed on the front surface portion 8 and the back surface portion 9 of the light guide plate 7. The prism sheet 12 can be provided on both surfaces (the front surface portion 8 side and the back surface portion 9 side) of the light guide plate 7. In this case, among the light traveling from the incident portion 10 into the light guide plate 7, the light beams L 1, L 2, L 3, and L 4 travel in the direction of the front surface portion 8 and the back surface portion 9. Total reflection is performed by the inclined surface of the portion 10 in the opposite direction. The totally reflected light beams L12, L22, L32, and L42 travel in the direction of the opposing surfaces, break the critical angle, and emit light beams L13, L23, L33, and L43 from the light guide plate 7. That is, light rays are emitted from opposite sides opposite to the surface on which the light deflection element 71 is provided.

  At this time, depending on the shape of the light deflection element 71 provided on the light guide plate 7 (the angle at which the light is totally reflected), in the case of the light rays L33 and L43 having a large emission angle, the apex angle is directed toward the light guide plate 7. By the prism sheet 12 provided on the upper portion (surface portion 8) of the light guide plate 7, the light beams L33 and L43 having a large emission angle are slightly refracted from one inclined surface of the prism sheet 12, and proceed into the prism sheet 12 as light beams L34 and L44. . The light beams L34 and L44 are further totally reflected at the other inclined surface of the prism sheet 12, and are deflected substantially perpendicular to the surface of the light guide plate 7 to emit light beams L35 and L45.

  Further, as shown in FIGS. 5 and 6, a light deflection element 71 is formed on either the front surface portion 8 or the back surface portion 9 of the light guide plate 7, and the surface side on which the light deflection element 71 is formed (FIG. 5 or FIG. 5). In the example of FIG. 6, the diffusion sheet 13 is provided on the back surface portion 9 side of the light guide plate 7 and the surface side where the light deflection element 71 is not formed (in the example of FIGS. 5 and 6, the surface portion 8 side of the light guide plate 7). ) May be provided with a prism sheet 12. In this case, of the light beams L01 and LL1 that have reached the light deflecting element 71 depending on the shape of the light deflecting element 71 and the incident angle of the light beam, a part of the light beams L02 undergo total reflection, and in the facing surface direction (surface portion 8). The light beam L03 is emitted to the outside by breaking the critical angle of the light guide plate 7. Further, a part of the light beam LL2 is refracted and transmitted by the light deflecting element 71 and emits the light beam LL3 to the outside.

  At this time, depending on the shape of the light deflecting element 71 provided on the light guide plate 7 (the angle at which the light is totally reflected), in the case of the light ray L03 having a large emission angle, the light guide plate 7 has an apex angle directed toward the light guide plate 7. The light beam L03 having a large emission angle is slightly refracted from one inclined surface of the prism sheet 12 by the prism sheet 12 provided on the upper portion (surface portion 8) of the light beam 7, and proceeds into the prism sheet 12 as the light beam L04. The light beam L04 is further totally reflected at the other inclined surface of the prism sheet 12, and is deflected substantially perpendicular to the surface of the light guide plate 7 to emit the light beam L05.

Further, the light beam refracted by the light deflecting element 71, transmitted, and emitted to the outside exits the light cone LLd which is diffused and spread by the diffusion sheet 13 which diffuses the light.
5 shows a case where the light deflection element 71 has a concave shape, and FIG. 6 shows a case where the light deflection element 71 has a convex shape.

  Further, as shown in FIG. 7, convex or concave light deflection elements 71 are formed on the front surface portion 8 and the back surface portion 9 of the light guide plate 7, and both surfaces of the light guide plate 7 (the front surface portion 8 side and the back surface portion 9 are formed). The prism sheet 12 can be provided on the side). In this case, the light beam LB reaching the light deflecting element 71 is refracted by the light deflecting element 71, and the light beam LB1 is emitted from the front surface portion 8 and the back surface portion 9 to the outside.

  At this time, the outgoing light beam LB1 is emitted in the opposite direction to the incident portion 10. Therefore, the light beam LB1 emitted from the light guide plate 7 is slightly refracted from one inclined surface of the prism sheet 12 by the prism sheet 12 whose apex angle is directed to the light guide plate 7 by the prism sheet 12 provided on the upper surface portion 8 and the back surface portion 9. Then, the light beam LB2 travels into the prism sheet 12. The light beam LB2 further undergoes total reflection at the other inclined surface of the prism sheet 12, and is deflected substantially perpendicular to the surface of the light guide plate 7 to emit the light beam LB3.

  Here, the light deflecting element 71 has been described with an arc-shaped convex shape, concave shape, or the like, but other shapes such as an elliptical arc, a cone, a cylinder, a polygonal pyramid, a polygonal column, etc. are used as the surface of the light guide plate 7. The light deflecting elements 71 having a convex shape or a concave shape having a circular arc shape or a polygonal cross section or a concave shape may be provided continuously or discontinuously.

  Further, even when the light deflection element 71 has a convex shape or concave shape such as an elliptical arc, a cone, a cylinder, a polygonal pyramid, a polygonal column, etc., the same operation and effect as those described above can be obtained, and the description will be repeated. Is omitted.

  Further, as shown in FIGS. 8, 9, and 10, the light guide plate 7 is formed of pillow-shaped convex portions and concave portions having an arc shape or a polygonal cross section on both surfaces or one surface of the front surface portion 8 or the back surface portion 9. The light deflection element 71 may be provided continuously or discontinuously at the concentric position.

  In the example of FIG. 8, in order to provide the light source 11 at the corner with respect to the light guide plate 7, the light deflection element 71 is provided at a concentric position centering on the light source 11 so as to face the light source 11. A storage portion 70 for storing the light source 11 in the light guide plate 7 is integrally formed at the corner of the light guide plate 7. And the light source 11 is inserted in this accommodating part 70, and the mechanical stability is aimed at.

  Further, in FIG. 8, the prism sheets 12 provided on both sides of the light guide plate 7 have an apex angle 72 having an arc distribution corresponding to the light deflection element 71 in the same manner as the light deflection element 71 provided on the light guide plate 7. The apex angle 72 faces the front surface portion 8 and the back surface portion 9 of the light guide plate 7.

  Further, as shown in FIGS. 9 and 10, the light deflection element 71 may be provided continuously or discontinuously at a concentric position with the light source 11 as the center with respect to the front surface portion 8 and the back surface portion 9 of the light guide plate 7.

  FIG. 9 shows the light source 11 provided at the corner of the light guide plate 7, and FIG. 10 shows the light source 11 provided at the center of the light guide plate 7. The ridges and valleys alternately become, for example, odd numbers become ridges S1, S3, etc., and even numbers become valleys S2, S4, etc.

  Note that the BB line in FIG. 9 and the aa line in FIG. 10 are perpendicular to the normal of the concentric ridges, and FIG. 11 is a partially enlarged side sectional view of the light guide plate along the BB line and the aa line. Is shown.

  Incidentally, the light deflection element 71 of the light guide plate 7 in the cross section taken along the line BB shown in FIG. 9 and the cross section taken along the line aa shown in FIG. 10 has a triangular cross section as shown in FIG. It does not have to be an isosceles triangle according to the light emitted from the front surface portion 8 and the back surface portion 9 of the light guide plate 7. The shape of the light deflection element 71 may be, for example, a right triangle or trapezoid, and a triangle or trapezoid whose inclined surface forms an arc.

  As shown in FIG. 11, when the light deflecting element 71 is provided on the front surface portion 8 or the back surface portion 9 of the light guide plate 7, the light beam LC0 reaching the light deflecting device 71 is refracted by the light deflecting device 71. Thus, the light beam LC1 is emitted from the front surface portion 8 and the back surface portion 9 to the outside.

  Further, the light beam LCr that is totally reflected by the light deflecting element 71 travels to the opposite surface, and is refracted by the light deflecting element 71, and the light beam LC1 is emitted from the front surface portion 8 and the back surface portion 9 to the outside.

  Furthermore, a prism sheet 12 is provided on the upper surface portion 8 and the rear surface portion 9, and the light beam LC1 emitted from the light guide plate 7 is slightly refracted from one inclined surface of the prism sheet 12 by the prism sheet 12 having an apex angle toward the light guide plate 7. Thus, the light beam LC2 advances into the prism sheet 12. This light beam LC2 is further totally reflected by another inclined surface of the prism sheet 12, and is deflected substantially perpendicularly to the surface of the light guide plate 7 to emit a light beam LC3.

  In the example of FIG. 8, the light deflection element 71 of the light guide plate 7 has a prism shape. However, as described above, a convex shape or a concave shape such as an arc, an elliptical arc, a cone, a cylinder, a polygonal pyramid, or a polygonal column is used. You may provide a dot in a concentric position continuously.

The prism sheet 12 is formed from a transparent resin such as acrylic resin (PMMA) or polycarbonate (PC). The prism sheet 12 forms a prism surface having a substantially triangular cross section or at least one inclined surface, and deflects light emitted from the light guide plate 7 substantially vertically to the light guide plate 7 to totally reflect the light.
Further, the prism sheet 12 can be provided in a straight shape on the sheet surface, or can be provided in a concentric arc shape as shown in FIGS.

  The diffusion sheet 13 is formed from a transparent resin such as acrylic resin (PMMA) or polycarbonate (PC). The diffusion sheet 13 has a minute uneven surface and plays a role of spreading light like a wide light cone.

Reflector 14, for example, as shown in FIG. 3, an opening hole 14a which is corresponding to the size of the liquid crystal panel 6 and the liquid crystal cell 6 of small to be used for the sub screen 6 or the like provided, a flat light source required for the sub screen 6 Is supplied to the liquid crystal panel 6, the liquid crystal cell 6, and the like.

  In addition, the light that has leaked from the light guide plate 7 to the light guide plate 7, the prism sheet 12, the diffusion sheet 13, and the like is returned to the light guide plate 7 again by a metal, a glossy material of metal, a white material, or the like. Use light.

  The light source 11 is composed of a CCFL (cold cathode tube) or the like, and has a linear line shape, an L shape (L), a U shape, or the like, and direct light enters the light guide plate 7 from the incident portion 10 of the light guide plate 7. To do. Further, if necessary, using a reflector or the like (not shown), light other than incident from the incident portion 10 enters the light guide plate 7 through the space between the light source 11 and the reflector while being reflected by the reflector.

  The light source 11 is not limited to a linear CCFL, and may be an array having semiconductor light emitting elements arranged as a linear light source.

  Further, the light source 11 is composed of, for example, an LED or a laser made of a semiconductor light emitting element, and is converted into white light by wavelength conversion using monochromatic light, white of RGB (red, green, blue) or a fluorescent material. It can also be used.

  Further, when the light guide plate 7 has a plurality of incident portions 10 at the corner where the two side surface portions intersect, white light is emitted from the entire light guide plate 7 using light sources 11 of different emission colors at the respective incident portions. It may be emitted.

  Although not shown here, a reflector made of a metal, a glossy material of metal, or a white material may be provided on the outer periphery of the light source 11.

  The liquid crystal panels 5 and 6 and the liquid crystal cells 5 and 6 are made of transmissive liquid crystal typified by TFTs and the like, have a large number of pixels corresponding to RGB, and have a light shutter function corresponding to RGB signals. Although not shown here, color filters corresponding to these RGB are also provided.

  By the way, in the present example, a liquid crystal display device including a flat illumination device may be configured as shown in FIG. In FIG. 12, the same components as those of the liquid crystal display device 1 of FIG. 3 are denoted by the same reference numerals, and the specific configuration and operation thereof are the same, and the description thereof is omitted.

12 includes a light source 11, a light guide plate 7, a prism sheet 12, a diffusion sheet 13, a polarization reflection sheet 21, a partially colored sheet 22, a case 23, a liquid crystal panel 5 or a liquid crystal cell 5 used as a main screen. The liquid crystal panel 6 or the liquid crystal cell 6 used as a sub-screen is schematically configured.

  The light source 11 supplies light to the incident portion 10 of the light guide plate 7. The light guide plate 7 has at least one side surface as an incident portion 10 and has a light deflection element 71 formed of a convex or concave prism or dot on the front surface portion 8 and / or the back surface portion 9 (see FIG. In the example of 12, the front surface portion 8 and the back surface portion 9).

  The prism sheet 12 is provided above the front surface portion 8 and below the back surface portion 9 of the light guide plate 7. The prism sheet 12 has a prism surface whose apex angle is directed to the light guide plate 7 and emits light beams emitted from the front surface portion 8 and the back surface portion 9 of the light guide plate 7 substantially vertically.

  The diffusion sheet 13 is provided above one prism sheet 12 and below the other prism sheet 12. The diffusion sheet 13 emits a light cone having a spread by diffusing the light emitted from the prism sheet 12 substantially vertically.

The polarization reflection sheet 21 is provided below the diffusion sheet 13 disposed on the back surface 9 side of the light guide plate 7. The polarizing reflection sheet 21 is a sub- light from the opening window 23a of the case 23 on the side of the liquid crystal panel 6 or the liquid crystal cell 6 used as a sub screen when a higher luminance is required as the required luminance of the flat illumination device (double-sided light emitting backlight). This is used to further improve the visibility of the screen. Further, the polarization reflection sheet 21 is installed so that the polarization axis is the same as the polarization axis of the liquid crystal panel 6 or the liquid crystal cell 6 used as the sub-screen.

  In the configuration including the polarization reflection sheet 21, only the P wave component of the P wave and S wave components radiated from the flat illumination device is transmitted with the direction axis aligned. At that time, natural light and S wave components are reflected and reflected to the flat illumination device side. The component of the light reflected toward the flat illumination device side is used for the increase in luminance on the liquid crystal panel 5 or liquid crystal cell 5 side used as the main screen. Thereby, the brightness | luminance of the liquid crystal panel 5 or the liquid crystal cell 5 side used as a main screen can be raised about 10 to 20%.

  Further, by utilizing the function of reflection of the polarizing reflection sheet 21, the liquid crystal panel 5 used as the main screen or the liquid crystal panel 6 used as the sub screen from the liquid crystal cell 5 side or the opening 23a of the case 23 facing the liquid crystal cell 6 is visually recognized. Can be reduced.

  Further, by matching the polarization axis of the polarizing reflection sheet 21 with the polarization axis of the liquid crystal panel 6 or liquid crystal cell 6 used as the sub screen, the luminance after transmission of the liquid crystal panel 6 or liquid crystal cell 6 used as the sub screen is about 5%. Can be increased by -10%.

The partially colored sheet 22 is located below the polarizing reflection sheet 21 and is disposed in the lowermost layer of the case 23 in which each component of the flat illumination device is accommodated. The partially colored sheet 22 has an opening 22 a corresponding to the opening window 23 a of the case 23. The opening 22a and the opening window 23a are formed in accordance with the size of the liquid crystal panel 6 or the liquid crystal cell 6 used as a sub-screen. And from the opening window 23a of the case 23 and the opening 22a of the partially colored sheet 22, the surface of the liquid crystal panel 6 or the liquid crystal cell 6 used as a sub-screen faces. A liquid crystal panel 5 or a liquid crystal cell 5 used as a main screen is disposed above the diffusion sheet 13 on the surface portion 8 side of the light guide plate 7.

By the way, when the opening 22a of the partially colored sheet 22 has the same size as the opening window 23a of the case 23, as shown in FIG. 13B, scattered light generated at the end face of the opening window 23a of the case 23. This causes a problem that the return light to the flat illumination device side cannot be blocked.

Therefore, in this example, when the case 23 is light (white), the opening 22a of the partially colored sheet 22 is set slightly smaller than the size of the opening window 23a of the case 23 as shown in FIG. is doing. Thereby, the return light to the plane illuminating device side of the scattered light generated at the end face of the opening window 23a of the case 23 can be shielded.

According to the configuration using the partially colored sheet 22, it is possible to reduce the contrast between the case 23 in which each component of the flat lighting device is accommodated and the opening window 23a.

More specifically, as shown in FIG. 14 (b), a conventional double-sided light emission type backlight includes a liquid crystal panel 6 or a liquid crystal cell 6 used as a sub-screen in the opening window 23a of the case 23 (a dark color and absorption unique to a polarizing plate). ) Is in a situation where it is viewed directly. For this reason, the difference in contrast between the case 23 and the liquid crystal panel 6 or the liquid crystal cell 6 used as the sub-screen is different from the side of the liquid crystal panel 5 or the liquid crystal cell 5 used as the main screen due to the difference in the degree of reflection. I can confirm.

Therefore, in this example, as shown in FIG. 14A, the lowermost layer on the liquid crystal panel 6 or liquid crystal cell 6 side used as the sub-screen, that is, the inner surface of the case 23 is colored with a dark color system (black, dark gray, etc.). The film-like partially colored sheet 22 is provided to reduce the contrast. Thereby, the visual recognition of the liquid crystal panel 5 used as the main screen or the liquid crystal panel 6 used as the sub screen from the liquid crystal cell 5 side or the opening window 23a of the case 23 facing the liquid crystal cell 6 can be suppressed.

  3 and 12 described above, the apex angle 72 of the prism surface of the prism sheet 12 provided on the front surface portion 8 and / or the back surface portion 9 of the light guide plate 7 faces the light guide plate 7 side. As shown in FIGS. 15 and 16, the apex angle 72 of the prism surface of the prism sheet 12 may be configured to face the opposite side of the light guide plate 7.

  15 is a schematic sectional side view showing another embodiment of a liquid crystal display device including a flat illumination device, and FIG. 16 is an exploded perspective view of the flat illumination device in FIG. Note that the same components as those in FIGS. 3 and 12 are denoted by the same reference numerals, and the specific configurations and functions thereof are the same, and the description thereof is omitted.

A liquid crystal display device 1 shown in FIG. 15 includes a light source 11, a light guide plate 7, a diffusion sheet 13, a prism sheet 12, a polarizing reflection sheet 21, a partially colored sheet 22, a case 23, a liquid crystal panel 5 or a liquid crystal cell 5 used as a main screen. The liquid crystal panel 6 or the liquid crystal cell 6 used as a sub-screen is schematically configured.

  The light source 11 supplies light to the incident portion 10 of the light guide plate 7. The light guide plate 7 has at least one side surface portion as an incident portion 10 and has a light deflection element 71 formed of a convex or concave prism or dot on the front surface portion 8 or the back surface portion 9 (see FIG. 15). In the example, the back surface 9).

  The diffusion sheet 13 is provided above the front surface portion 8 of the light guide plate 7 and below the back surface portion 9. The diffusion sheet 13 emits a light cone having a spread by diffusing light emitted from the front surface portion 8 and the back surface portion 9 of the light guide plate 7.

  The prism sheet 12 is composed of a pair of prism sheets 12A and 12B whose prism surfaces intersect each other (90 °). The prism sheet 12 is provided above one diffusion sheet 13 and below the other diffusion sheet 13. The pair of prism sheets 12 </ b> A and 12 </ b> B has a prism surface whose apex angle is directed to the opposite side of the light guide plate 7, and emits light beams emitted from the diffusion sheet 13 substantially vertically.

  The polarizing reflection sheet 21 is provided below the prism sheet 12 disposed on the back surface 9 side of the light guide plate 7. The polarization reflection sheet 21 is installed so that the polarization axis is the same as the polarization axis of the liquid crystal panel 6 or the liquid crystal cell 6 used as a sub-screen, and has the above-described functions and effects.

The partially colored sheet 22 has the above-described functions and functions described with reference to FIGS. 13 and 14. This partially colored sheet 22 is located below the polarizing reflection sheet 21 and is disposed in the lowermost layer of the case 23 in which each component of the flat illumination device is accommodated. The partially colored sheet 22 has an opening 22 a corresponding to the opening window 23 a of the case 23. And from the opening window 23a of the case 23 and the opening 22a of the partially colored sheet 22, the surface of the liquid crystal panel 6 or the liquid crystal cell 6 used as a sub-screen faces. A liquid crystal panel 5 or a liquid crystal cell 5 used as a main screen is disposed above the prism sheet 12 on the surface portion 8 side of the light guide plate 7.

The opening 22a of the partially colored sheet 22 is set slightly smaller than the size of the opening window 23a of the case 23 when the case 23 is light (white). Thereby, the return light to the plane illuminating device side of the scattered light generated at the end face of the opening window 23a of the case 23 can be shielded.

  When the liquid crystal display device 1 configured as described above is employed in, for example, a mobile phone having a camera function, it can serve as a finder and check a still image such as a photograph. Similarly, in the case of a moving image, it can serve as a finder view (monitor) of the video camera and confirm a moving image.

Incidentally, in the liquid crystal display device 1 shown in FIGS. 12 and 15, instead of the case 23, as a reflector 14 having an opening hole 14a which is corresponding to the size of the liquid crystal panel 6 and the liquid crystal cell 6 of small to be used for the sub-screen Also good.

(A), (b) It is a schematic perspective view of the liquid crystal display device which concerns on this invention which has arrange | positioned the plane illuminating device which radiate | emits from both surfaces between two liquid crystal panels or liquid crystal cells, The front perspective view and back perspective view of a mobile telephone Figure (A), (b) It is a schematic perspective view of the liquid crystal display device which concerns on this invention which has arrange | positioned the plane illuminating device which radiate | emits from both surfaces between two liquid crystal panels or liquid crystal cells, A front perspective view of a foldable mobile phone, Rear perspective view It is a schematic side sectional view of the liquid crystal display device according to the present invention, and shows an example in which a main liquid crystal display device and a sub liquid crystal display device are provided on both sides of one flat illumination device. Partial enlarged side sectional view which shows an example of the plane illuminating device which concerns on this invention Partially enlarged side sectional view showing another example of the flat illumination device according to the present invention Partially enlarged side sectional view showing another example of the flat illumination device according to the present invention The disassembled perspective view which shows the other example of the planar illuminating device which concerns on this invention. Schematic perspective view showing still another example of the flat illumination device according to the present invention. The top view which shows an example of the light-guide plate of the plane illuminating device which concerns on this invention The top view of the other example which shows the positional relationship of the light deflection element formed in the light-guide plate of the planar illuminating device which concerns on this invention, and a light source. It is the fragmentary sectional view of the BB line of FIG. 9, and the aa line of FIG. 10, and the top view and back view of a liquid crystal display device which employ | adopted the planar illuminating device which concerns on this invention. FIG. 4 is a schematic side sectional view showing another embodiment of a liquid crystal display device including a flat illumination device according to the present invention. (A) opening window of the reflector partial sectional view of the case of providing the inner surface of the partially colored sheet reflectors having an opening window smaller than the opening of the (case) (case) (b) reflector (case) and partial sectional view of the partially colored sheet disposed on the inner surface side of the reflector (case) having an opening the same size (A) partial cross-sectional view of a case where there is no partial colored sheet on the inner surface side of the partial cross-section when the inner surface partially colored sheet is in the diagram (b) reflector (case) of the reflector (case) FIG. 6 is a schematic side sectional view showing still another embodiment of a liquid crystal display device including a flat illumination device according to the present invention. FIG. 15 is an exploded perspective view of a flat illumination device in the liquid crystal display device of FIG.

DESCRIPTION OF SYMBOLS 1 Liquid crystal display device 2 Cellular phone 3 Front side case 4 Back side case 5 Main screen (main liquid crystal panel, main liquid crystal cell)
6 Sub screen (Sub LCD panel, Sub LCD cell)
DESCRIPTION OF SYMBOLS 7 Light guide plate 8 Front surface part 9 Back surface part 10 Incident part 11 Light source 12 Prism sheet 13 Diffusion sheet 14 Reflector 14a Opening hole 21 Polarization reflection sheet 22 Partially colored sheet 22a Opening part 23 Case 23a Opening window 70 Storage part 71 Optical deflection element 72 Apex angle of arc distribution prism sheet α Refraction angle n Refractive index γ Critical angle S1, S3 Convex ridge line S2, S4 Valley (concave ridge) line LLd Light cone L01, L02, L03, L04, L05, L1, L2, L3 , L4, L12, L13, L22, L23, L32, L33, L34, L35, L42, L43, L44, L45, LB, LB1, LB2, LB3, LL1, LL2, LL3

Claims (7)

At least a main liquid crystal panel, a sub liquid crystal panel smaller than the main liquid crystal panel, and a light guide plate that emits light from both the front and back surfaces provided between the main liquid crystal panel and the sub liquid crystal panel . a liquid crystal display device which have a a flat illumination device,
A partial partially colored sheet having an opening slightly smaller than the size of the opening window is provided as a case facing the sub liquid crystal panel and having an opening window slightly smaller than the sub liquid crystal panel. A liquid crystal display device provided between the case facing the sub liquid crystal panel and the light guide plate . The partial colored sheet, a liquid crystal display device according to claim 1 Symbol mounting, characterized in that a is colored with a dark color film. The light guide plate, a light deflection element is provided in a surface portion and / or back surface, total reflection and / or refraction, No placement claim 1 Symbol, characterized in that emitted from both surfaces of its surface and the opposing surface Liquid crystal display device. The planar lighting device, a liquid crystal display device according to claim 1, characterized in that a prism sheet or / and diffusion sheet or / and polarization reflecting sheet to the surface portion and / or the back surface side of the light guide plate . The flat illumination device faces the sub liquid crystal panel on one side of the light guide plate, and is slightly smaller than the sub liquid crystal panel between the case and the partially colored sheet inside the case or the opening window. the liquid crystal display device according to claim 1, characterized in that a reflector which has the same opening hole with. The light deflecting element is a true arc, an elliptic arc, a cone, a cylinder, a polygonal pyramid, a polygonal column shape and a continuous or non-continuous cross section consisting of a convex portion or a concave portion of either an arc shape or a polygonal pillow shape, 4. The liquid crystal display device according to claim 3, wherein the light guide plate is provided at random or concentric positions on a front surface portion and / or a back surface portion of the light guide plate. 5. The liquid crystal display device according to claim 4 , wherein the prism sheet has a substantially triangular shape or at least one inclined surface, and has a straight shape or a concentric arc shape on the prism sheet surface.

Images