JP2008070418A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device of a transmission/reflection dual purpose type, wherein a viewing angle characteristic of a transmission mode display is sufficiently improved and a bright display in reflection mode is attained. <P>SOLUTION: The liquid crystal display device is provided with a liquid crystal display panel 20 and an illumination element 10 which emits light toward the liquid crystal display panel 20, and has a plurality of pixels for performing display. Each of the plurality of pixels has a transmission region T of performing a transmission mode display by using light from the illumination element 10 and a reflection region R of performing a reflection mode display by using light from the observer side, and the liquid crystal display panel 20 has a first light diffusion layer 31 and a second light diffusion layer 32 which are disposed on the observer side than a liquid crystal layer 23. The first light diffusion layer 31 is arranged in the transmission region T and the second light diffusion layer 32 is arranged in the reflection region R. The haze value of the second light diffusion layer 32 is smaller than the haze value of the first light diffusion layer 31. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device, and more particularly to a transmission / reflection liquid crystal display device capable of performing transmission mode display and reflection mode display.

  In recent years, portable electronic devices represented by portable telephones and PDAs (Personal Digital Assistants) have been widely used. A liquid crystal display device having advantages such as thinness, light weight, and low power consumption is used for a display portion of a portable electronic device.

  The liquid crystal display device is not a self-luminous display device such as a CRT or a PDP (plasma display panel). Therefore, in a transmissive liquid crystal display device, an illumination element called a backlight is provided on the back side of the liquid crystal display panel, and the liquid crystal display panel controls the amount of transmitted illumination light from the backlight for each pixel. The image is displayed by.

  Various types of liquid crystal display devices are known. However, some methods (for example, a method using a TN type or STN type liquid crystal display element) have a disadvantage that the viewing angle is narrow, and various technical developments have been made to solve the problem. Yes.

  As a typical technique for improving the viewing angle characteristics of a liquid crystal display device, there is a method of adding an optical compensator. Further, the light emitted from the backlight is made incident on the liquid crystal display element after increasing its directivity (parallelism), and the light that has passed through the liquid crystal display element is received by a lenticular lens sheet disposed in front of the liquid crystal display element. A diffusion method is also known (for example, Patent Document 1).

  FIG. 9 shows a liquid crystal display device 800 disclosed in Patent Document 1. The liquid crystal display device 800 includes a liquid crystal display panel 820 including a liquid crystal layer (not shown), a backlight 810 disposed on the back side of the liquid crystal display panel 820, and a lenticular lens disposed on the viewer side of the liquid crystal display panel 820. And a sheet 830.

  The backlight 810 includes a light source 801, a light guide plate 802 that guides light emitted from the light source 801 to the liquid crystal display panel 820, and a reflective layer 804 that reflects light leaking from the light guide plate 802 toward the light guide plate 802. Yes. The light guide plate 802 has an emission surface that emits light toward the liquid crystal display panel 820, and a back surface that faces the emission surface, and a plurality of prisms 802a are formed on the back surface.

  The light emitted from the light source 801 is reflected on the liquid crystal display panel 820 side by the prism 802a on the back surface while propagating through the light guide plate 802, and is emitted from the emission surface. The prism 802a on the back surface has two inclined surfaces that are inclined at predetermined angles different from each other with respect to the emission surface, so that the light emitted from the backlight 810 is normal to the display surface (front direction). ) Is significantly stronger. That is, the light emitted from the backlight 810 is given high directivity.

  If the light emitted from the backlight 810 has high directivity, the light passing through the liquid crystal layer of the liquid crystal display panel 820 can be uniformly modulated (that is, the light passing through the liquid crystal layer is uniform). Therefore, the viewing angle dependence of the display quality due to the refractive index anisotropy of the liquid crystal molecules can be reduced. The light that has passed through the liquid crystal display panel 820 has high directivity as it is and has a large bias in luminance (the luminance in the normal direction of the display surface is extremely high and the luminance in the oblique direction is low). Is diffused by the lenticular lens sheet 830, thereby reducing the unevenness of luminance, thereby widening the viewing angle. In this manner, the liquid crystal display device 800 realizes a wide viewing angle display in which the viewing angle dependency of the display quality is reduced.

  On the other hand, in recent years, a liquid crystal display device capable of high-quality display both outdoors and indoors has been proposed (for example, Patent Document 2). This liquid crystal display device can perform a transmission mode display using light from a backlight and a reflection mode display using ambient light (external light), and is referred to as a transflective liquid crystal display device.

  The transflective liquid crystal display device performs display with a bright high contrast ratio that is less affected by the low power consumption characteristic of the reflective liquid crystal display device and the ambient brightness of the transmissive liquid crystal display device. It has the feature of being able to. Further, the disadvantage of the transmissive liquid crystal display device that visibility is deteriorated in a very bright usage environment (for example, outdoors on a sunny day) is also improved.

However, the transflective liquid crystal display device disclosed in Patent Document 2 does not include a light diffusing element on the viewer side of the liquid crystal layer, and therefore cannot display a wide viewing angle. Therefore, it is conceivable to apply a method using a light diffusing element as disclosed in Patent Document 1 to a transflective liquid crystal display device.
JP-A-9-22011 Japanese Patent Laid-Open No. 11-101992

  However, even if the method disclosed in Patent Document 1 is applied to a transflective liquid crystal display device as it is, it is difficult to perform high-quality display in both the transmissive mode and the reflective mode. This is because when a light diffusing element is simply provided in a transmissive / reflective liquid crystal display device, light used for transmissive mode display (light from the backlight) passes through the light diffusing element only once. This is because light used for mode display (light from the observer side) passes through the light diffusing element twice.

  For example, when the haze value (the degree of light diffusion) of the light diffusing element is optimized with respect to the light used for the transmission mode display, the light used for the reflection mode display passes through the light diffusing element twice. Since the light is excessively diffused, the reflection mode display becomes dark.

  Also, if the haze value of the light diffusing element is set to be weak so that the display in the reflection mode does not become dark, the light used for the display in the transmission mode is not sufficiently diffused because it passes through the light diffusing element only once. The viewing angle cannot be sufficiently wide for the display in the transmission mode.

  The present invention has been made in view of the above problems, and an object of the present invention is to sufficiently improve the viewing angle characteristics of a transmission mode display and to display a bright display in a reflection mode in a transmission / reflection liquid crystal display device. Is to realize.

  A liquid crystal display device according to the present invention includes a liquid crystal display panel having a pair of substrates and a liquid crystal layer provided between the pair of substrates, and an illumination element that emits light toward the liquid crystal display panel, and performs display. A liquid crystal display device having a plurality of pixels for each of the plurality of pixels, wherein each of the plurality of pixels uses a transmissive region that performs display in a transmissive mode using light from the illumination element and light from an observer side. The liquid crystal display panel includes first and second light diffusing layers provided closer to the viewer than the liquid crystal layer, and the first light diffusing layer is provided. The layer is disposed in the transmission region, the second light diffusion layer is disposed in the reflection region, and the haze value of the second light diffusion layer is the first light diffusion. Less than the haze value of the layer.

  In a preferable embodiment, the haze value of the first light diffusion layer is 85% or more.

  In a preferred embodiment, the haze value of the second light diffusion layer is 83% or less.

  In a preferred embodiment, the haze value of the second light diffusion layer is 70% or more.

  In a preferred embodiment, the pair of substrates includes a first substrate disposed on the viewer side with respect to the liquid crystal layer and a second substrate disposed on the side opposite to the viewer with respect to the liquid crystal layer. The first and second light diffusion layers are disposed between the first substrate and the liquid crystal layer.

  In a preferred embodiment, the liquid crystal display panel further includes a light reflection layer disposed closer to the illumination element than the liquid crystal layer.

  In a preferred embodiment, the illumination element has a light distribution such that luminance in a direction forming an angle of 30 ° or more with respect to the normal direction of the display surface is 13% or less of luminance in the normal direction of the display surface. Have

  In a preferred embodiment, the illumination element has a light distribution such that luminance in a direction forming an angle of 30 ° or more with respect to the normal direction of the display surface is 3% or less of luminance in the normal direction of the display surface. Have

  In a preferred embodiment, the illumination element includes a light source and a directivity control element that controls the directivity of light emitted from the light source.

  The liquid crystal display panel included in the liquid crystal display device according to the present invention includes a first light diffusion layer disposed in the transmission region and a second light diffusion layer disposed in the reflection region. The haze value of the light diffusion layer is smaller than the haze value of the first light diffusion layer. In other words, the light diffusion layer that diffuses light weaker than the light diffusion layer provided in the transmission region is provided in the reflection region. Therefore, the number of times of passing through the light diffusion layer is different between the light used for display in the transmission mode (light from the illumination element) and the light used for display in the reflection mode (light from the observer side) (each 1 Despite this, the light used in the transmission mode can be sufficiently diffused without excessively diffusing the light used in the reflection mode. Therefore, it is possible to sufficiently improve the viewing angle characteristics of the display in the transmission mode and realize a bright display in the reflection mode.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, this invention is not limited to the following embodiment.

  FIG. 1 shows a transflective liquid crystal display device 100 according to this embodiment. As shown in FIG. 1, the liquid crystal display device 100 includes a liquid crystal display panel 20 and a lighting element (backlight) 10 that emits light toward the liquid crystal display panel 20, and has a plurality of displays. Has pixels. Each of the plurality of pixels includes a transmissive region T that performs display in a transmissive mode using light from the illumination element 10 and a reflective region R that performs display in a reflective mode using light from the viewer side. Yes.

  The liquid crystal display panel 20 includes a pair of substrates 21 and 22 and a liquid crystal layer 23 provided therebetween. On the surface of the substrates 21 and 22 on the liquid crystal layer 23 side, electrodes for applying a voltage to the liquid crystal layer 23 and alignment films (both not shown) for defining the alignment direction of the liquid crystal layer 23 are formed. Yes. Hereinafter, of the pair of substrates 21 and 22, the substrate 21 disposed on the illumination element 10 side of the liquid crystal layer 23, that is, on the opposite side of the liquid crystal layer 23 from the observer is referred to as a “rear substrate”. The substrate 22 disposed on the viewer side with respect to the layer 23 is referred to as a “front substrate”.

  A light reflecting layer 24 is provided on the rear substrate 21 on the liquid crystal layer 23 side. The light reflection layer 24 is selectively formed in the reflection region R. In other words, the reflection region R is defined by the light reflection layer 24, and the transmission region T is defined by the region 25 of the back substrate 21 where the light reflection layer 24 is not formed. The light reflecting layer 24 is made of a metal having a high light reflectivity such as aluminum or silver, and has a thickness (for example, about 100 nm) that can reflect light with a sufficiently high reflectivity. . The light reflecting layer 24 may function as an electrode for applying a voltage to the liquid crystal layer 23.

  A color filter 26 and a black matrix 27 are provided on the front substrate 22 on the liquid crystal layer 23 side. The color filter 26 typically includes a red (R) color filter, a green (G) color filter, and a blue (B) color filter.

  On the surface of the front substrate 22 on the viewer side, retardation plates 41 and 42 and a polarizing plate (polarizing element) 51 are provided in this order. In addition, retardation plates 43 and 44 and a polarizing plate (polarizing element) 52 are provided in this order on the surface of the back substrate 21 opposite to the viewer.

  In this embodiment, two retardation plates 41 and 42 are arranged between the polarizing plate 51 on the observer side and the liquid crystal layer 23, and the polarizing plate 52 on the lighting element 10 side and the liquid crystal layer 23 are disposed. Although the two retardation plates 43 and 44 are arranged in the above, the number and arrangement of the retardation plates are not limited to those exemplified here.

  The liquid crystal display panel 20 in the present embodiment includes a first light diffusion layer 31 and a second light diffusion layer 32 that are provided closer to the viewer than the liquid crystal layer 23. In the present embodiment, the first light diffusion layer 31 and the second light diffusion layer 32 are provided between the front substrate 22 and the color filter 26. As shown in FIG. 1, the first light diffusion layer 31 is disposed in the transmission region T, and the second light diffusion layer 32 is disposed in the reflection region R. When the liquid crystal display device 100 has an R pixel that displays red, a G pixel that displays green, and a B pixel that displays blue, as illustrated in FIG. 2, in each of the R pixel, the G pixel, and the B pixel, A first light diffusion layer 31 is disposed in T, and a second light diffusion layer 32 is disposed in the reflection region R.

  The first light diffusion layer 31 and the second light diffusion layer 32 have different light diffusion characteristics. Specifically, the haze value of the second light diffusion layer 32 (a parameter indicating the degree of light diffusion) is smaller than the haze value of the first light diffusion layer 31. That is, the second light diffusion layer 32 diffuses light weaker than the first light diffusion layer 31.

  The illumination element 10 emits light with high directivity. If the light emitted from the illumination element 10 has high directivity, the light passing through the liquid crystal layer 23 can be uniformly modulated (that is, the light passing through the liquid crystal layer 23 is given uniform retardation). Therefore, the viewing angle dependency of the display quality due to the refractive index anisotropy of the liquid crystal molecules can be reduced.

  The illumination element 10 includes a light source 1 and a light guide plate (light guide) 2 that guides light emitted from the light source 1 to the liquid crystal display panel 20. The light source 1 is, for example, a light emitting diode (LED) or a cold cathode tube. The light guide plate 2 has a structure for emitting light emitted from the light source 1 and entering the light guide plate 2 to the liquid crystal display panel 20 side. For example, a prism or a texture is formed on at least one of the two main surfaces of the light guide plate 2.

  A reflection sheet 3 is disposed on the back side of the light guide plate 2. The reflection sheet 3 reflects the light leaked from the light guide plate 2 to the back side toward the light guide plate 2 again.

  Further, a diffusion sheet 4, a lower lens sheet 5, and an upper lens sheet 6 are arranged in this order on the front side of the light guide plate 2. The diffusion sheet 4, the lower lens sheet 5, and the upper lens sheet 6 function as directivity control elements that control the directivity of light.

  The light emitted from the light guide plate 2 is once diffused by the diffusion sheet 4 and then condensed by the lower lens sheet 5 and the upper lens sheet 6. For example, one of the lower lens sheet 5 and the upper lens sheet 6 is focused in the vertical direction of the display surface, and the other is focused in the horizontal direction of the display surface.

  The upper lens sheet 6 further functions as a reflective polarizing plate. That is, only a specific polarization component (specifically, P wave) of the light from the lower lens sheet 5 is transmitted, and the other polarization component (specifically, S wave) is reflected. The upper lens sheet 6 that functions as a reflective polarizing plate is disposed such that its transmission axis coincides with the transmission axis of the polarizing plate 52 on the back side of the liquid crystal display panel 20.

  When the upper lens sheet 6 that functions as a reflective polarizing plate is not provided, the S wave of the light from the lower lens sheet 5 is absorbed by the polarizing plate 52 as shown on the left side of FIG. , Not used for display.

  On the other hand, when the upper lens sheet 6 functioning as a reflection type polarizing plate is provided, the S wave of the light from the lower lens sheet 5 is caused by the upper lens sheet 6 as shown on the right side of FIG. Reflected. The reflected S wave passes through the lower lens sheet 5, the diffusion sheet 4, and the light guide plate 2, is reflected by the reflection sheet 3, and travels toward the upper lens sheet 6 again. In this process, a part of the S wave is converted into a P wave, and is incident on the liquid crystal display panel 20 without being reflected by the upper lens sheet 6 or absorbed by the polarizing plate 52. Therefore, the light utilization efficiency is increased and the luminance is improved. As the upper lens sheet 6 that functions as a reflective polarizing plate, for example, BEF-RP manufactured by Sumitomo 3M Limited can be used.

  The light emitted from the illumination element 10 enters the liquid crystal display panel 20 through the polarizing plate 52, and then the retardation plates 44 and 43, the rear substrate 21, the liquid crystal layer 23, the color filter 26, and the first light diffusion layer. 31, the front substrate 22, and the phase difference plates 41 and 42 are sequentially passed. By modulating the light in this process, the amount of light that passes through the polarizing plate 51 on the viewer side is controlled, thereby displaying the transmission mode.

  Since the illumination element 10 can emit light with high directivity, in the transmission mode in which display is performed using light from the illumination element 10, the display quality depends on the viewing angle due to the refractive index anisotropy of liquid crystal molecules. Can be reduced. Simply using light with high directivity causes a large bias in luminance (the luminance in the normal direction of the display surface is extremely high and the luminance in the oblique direction is low), but in this embodiment, the light used in the transmission mode Is diffused by the first light diffusing layer 31, so that the luminance deviation is reduced, thereby widening the viewing angle.

  Ambient light (external light) is incident on the liquid crystal display panel 20 from the observer side via the polarizing plate 51, and then the phase difference plates 42 and 41, the front substrate 22, the second light diffusion layer 32, and the color. The light passes through the filter 26 and the liquid crystal layer 23 in order and is reflected by the light reflection layer 24, and again passes through the liquid crystal layer 23, the color filter 26, the second light diffusion layer 32, the front substrate 22, and the phase difference plates 41 and 42. By modulating the light in this process, the amount of light that passes through the polarizing plate 51 on the viewer side is limited, thereby displaying the reflection mode.

  The light used in the reflection mode is incident on the liquid crystal display panel 20 from the observer side, is reflected by the light reflecting layer 24, and is diffused by the second light diffusion layer 32 in the process of exiting to the observer side. The reflection due to the specular reflection at the light reflection layer 24 is prevented, and a suitable white display can be performed in the reflection mode. The viewing angle is also enlarged. Note that the arrangement of the light reflecting layer 24 is not limited to that illustrated. The light reflection layer 24 only needs to be disposed closer to the lighting element 10 than the liquid crystal layer 23.

  Thus, the liquid crystal display device 100 can perform transmission mode display using light from the illumination element 10 and reflection mode display using light from the viewer side.

  In the transflective liquid crystal display device 100 according to this embodiment, the first light diffusion layer 31 is provided in the transmission region T, and the second light diffusion layer 32 is provided in the reflection region R. In addition, the haze value of the second light diffusion layer 32 is smaller than the haze value of the first light diffusion layer 31. That is, a light diffusion layer that diffuses light weaker than the light diffusion layer provided in the transmission region T is provided in the reflection region R. Therefore, the number of times of passing through the light diffusion layer is different between the light used for display in the transmission mode (light from the illumination element) and the light used for display in the reflection mode (light from the observer side) (each 1 Despite this, the light used in the transmission mode can be sufficiently diffused without excessively diffusing the light used in the reflection mode. Therefore, it is possible to sufficiently improve the viewing angle characteristics of the display in the transmission mode and realize a bright display in the reflection mode. That is, it is possible to achieve both a wide viewing angle transmission mode and a high reflectance reflection mode.

  On the other hand, in the configuration in which the common light diffusion layer 631 is provided in the transmission region T and the reflection region R as in the liquid crystal display device 600 of the comparative example shown in FIG. 4, the haze value of the light diffusion layer 631 is set to the transmission mode. When the light used for the display is optimized, the light used for the reflection mode display is excessively diffused by passing through the light diffusion layer 631 twice, so that the reflection mode display becomes dark.

  If the haze value of the light diffusion layer 631 is set to be weak so that the reflection mode display does not become dark, the light used for the transmission mode display passes through the light diffusion layer 631 only once and is not sufficiently diffused. Therefore, the viewing angle cannot be sufficiently widened for the transmission mode display.

  Here, specific structures and preferred configurations of the first light diffusion layer 31 and the second light diffusion layer 32 will be described.

  The first light diffusion layer 31 and the second light diffusion layer 32 are light diffusion elements using internal scattering as shown in FIG. 5, for example. The first light diffusing layer 31 (or the second light diffusing layer 32) shown in FIG. 5 includes a matrix 33 formed of a resin material and a matrix 33 as shown in a partially enlarged view in the figure. And dispersed particles 34. The particles 34 have a refractive index different from the refractive index of the matrix 33, and light is diffused by scattering due to the difference in refractive index between the matrix 33 and the particles 34.

  A desired haze value can be obtained by adjusting the refractive index difference between the matrix 33 and the particles 34 and the mixing ratio of the particles 34. Accordingly, the first light diffusion layer 31 and the second light diffusion layer 32 can have different haze values by making the difference in refractive index between the matrix 33 and the particles 34 and the mixing ratio of the particles 34 different. . Moreover, since the haze value can be changed also by adjusting the thickness, the haze value can be varied by varying the thickness between the first light diffusion layer 31 and the second light diffusion layer 32. Also good. The first light diffusion layer 31 and the second light diffusion layer 32 are not limited to those illustrated, and various light diffusion elements can be used.

  The haze values of the first light diffusion layer 31 and the second light diffusion layer 32 are appropriately set according to the specifications of the liquid crystal display panel 20, desired display characteristics, and the like.

  In order to sufficiently expand the viewing angle of the transmission mode, the haze value of the first light diffusion layer 31 is preferably 85% or more. FIG. 6 shows the relationship between the haze value of the first light diffusion layer 31 and the viewing angle. The haze value can be measured, for example, with a haze meter NDH2000 manufactured by Nippon Denshoku Industries Co., Ltd. Further, the viewing angle shown in FIG. 6 is an angle range with a contrast ratio of 2 or more along a certain direction (for example, the vertical direction) in the display surface.

  As can be seen from FIG. 6, when the haze value of the first light diffusion layer 31 was 85% or more, a viewing angle of 40 ° or more was obtained, and the effect of widening the viewing angle was remarkable. Accordingly, the haze value of the first light diffusing element 31 is preferably 85% or more.

  In order to display the reflection mode appropriately, the haze value of the second light diffusion layer 32 is preferably 70% or more and 83% or less. FIG. 7 shows the relationship between the haze value of the second light diffusion layer 32 and the light reflectance of the liquid crystal display panel 20 (hereinafter simply referred to as “panel reflectance”).

  As can be seen from FIG. 7, when the haze value is less than 70%, the panel reflectivity is 10% or more lower than the maximum reflectivity (around 80% haze value). Therefore, from the viewpoint of securing a high panel reflectivity, the haze value of the second light diffusion layer 32 is preferably 70% or more.

  Further, when the haze value of the second light diffusion layer 32 was changed and the blur of display in the reflection mode was visually evaluated, if the haze value exceeded 83%, an unacceptable display blur could occur. For this reason, the haze value of the second light diffusion layer 32 is preferably 83% or less.

  In the configuration shown in FIG. 1, the first light diffusion layer 31 and the second light diffusion layer 32 are provided between the front substrate 22 and the liquid crystal layer 23, but the first light diffusion layer 31 is provided. The second light diffusion layer 32 may be provided on the viewer side of the front substrate 22. When the first light diffusion layer 31 and the second light diffusion layer 32 are provided between the front substrate 22 and the liquid crystal layer 23, from the liquid crystal layer 23 to the first light diffusion layer 31 and the second light diffusion layer 32. The distance becomes shorter and the display blur is less likely to occur.

  The illumination element 10 is not limited to the exemplified elements, and various backlights that can emit light with high directivity can be used. In order to obtain higher display quality, it is preferable to use a backlight that can emit light with higher directivity. Specifically, the illumination element 10 has a light distribution such that the luminance in a direction that forms an angle of 30 ° or more with respect to the normal direction of the display surface is 3% or less of the luminance in the normal direction of the display surface. A sufficiently high contrast ratio can be easily realized.

  FIGS. 8A and 8B show examples of preferable light distribution of the illumination element 10. In the light distribution shown in FIG. 8A, the luminance in the normal direction of the display surface is the highest, and the luminance suddenly decreases as the angle increases. In contrast, in the light distribution shown in FIG. 8B, a relatively high luminance is maintained from the normal direction of the display surface to around 30 °. In both of the light distributions shown in FIGS. 8A and 8B, the luminance in the direction forming an angle of 30 ° or more with respect to the display surface normal direction is the luminance in the display surface normal direction (0 °). 3% or less. Therefore, excellent display quality can be obtained by using the illumination element 10 having such a light distribution.

  Another example of the light distribution is shown in FIG. In the light distribution shown in FIG. 8C, the luminance in a direction that forms an angle of 30 ° or more with respect to the display surface normal direction is 8% to 13% or less of the luminance in the display surface normal direction (0 °). It is. Even when the lighting element 10 having such a light distribution is used, sufficient display quality can be obtained.

  According to the present invention, it is possible to sufficiently improve the viewing angle characteristics of the transmission mode display and realize a bright display in the reflection mode in the transmission / reflection liquid crystal display device. That is, it is possible to achieve both a wide viewing angle transmission mode and a high reflectance reflection mode.

  The liquid crystal display device according to the present invention is suitably used for all transmissive liquid crystal display devices having a backlight, and in particular, a liquid crystal display in a display mode (for example, STN mode, TN mode, ECB mode) having a low viewing angle characteristic. It is suitably used for an apparatus.

It is sectional drawing which shows typically the liquid crystal display device 100 in suitable embodiment of this invention. It is a top view which shows the example of arrangement | positioning of the 1st and 2nd light-diffusion layer in each of R pixel, G pixel, and B pixel. It is a figure for demonstrating the function of the lens sheet which functions as a reflection type polarizing plate. It is sectional drawing which shows typically the liquid crystal display device 600 provided with the light-diffusion layer common to a transmissive area | region and a reflective area | region. It is a figure which shows an example of the 1st and 2nd light-diffusion layer used for the liquid crystal display device of this invention. It is a graph which shows the relationship between the haze value (%) of a 1st light-diffusion layer, and a viewing angle (degree). It is a graph which shows the relationship between the haze value (%) of a 2nd light-diffusion layer, and panel reflectivity (%). (A), (b) and (c) is a graph which shows the example of the light distribution of the light radiate | emitted from an illumination element. It is a perspective view which shows the conventional liquid crystal display device 800 typically.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light source 2 Light guide plate 3 Reflection sheet 4 Diffusion sheet 5, 6 Lens sheet 10 Illumination element (backlight)
DESCRIPTION OF SYMBOLS 20 Liquid crystal display panel 21 Back substrate 22 Front substrate 23 Liquid crystal layer 24 Light reflection layer 25 Area | region in which the light reflection layer is not formed 26 Color filter 27 Black matrix 31 1st light diffusion layer 32 2nd light diffusion layer 33 Matrix 34 Particles 41, 42, 43, 44 Retardation plates 51, 52 Polarizing plate 100 Liquid crystal display device

Claims (9)

A liquid crystal display panel comprising a pair of substrates and a liquid crystal layer provided between the pair of substrates, and an illumination element that emits light toward the liquid crystal display panel, and having a plurality of pixels for display A display device,
Each of the plurality of pixels includes a transmissive region that performs display in transmissive mode using light from the illumination element, and a reflective region that performs display in reflective mode using light from the viewer side,
The liquid crystal display panel has first and second light diffusion layers provided closer to the viewer than the liquid crystal layer,
The first light diffusion layer is disposed in the transmission region;
The second light diffusion layer is disposed in the reflective region;
The liquid crystal display device, wherein a haze value of the second light diffusion layer is smaller than a haze value of the first light diffusion layer.   The liquid crystal display device according to claim 1, wherein the first light diffusion layer has a haze value of 85% or more.   The liquid crystal display device according to claim 1, wherein a haze value of the second light diffusion layer is 83% or less.   The liquid crystal display device according to claim 1, wherein the second light diffusion layer has a haze value of 70% or more. The pair of substrates are a first substrate disposed closer to the viewer than the liquid crystal layer and a second substrate disposed on the opposite side of the viewer from the liquid crystal layer,
5. The liquid crystal display device according to claim 1, wherein the first and second light diffusion layers are disposed between the first substrate and the liquid crystal layer. 6.   6. The liquid crystal display device according to claim 1, wherein the liquid crystal display panel further includes a light reflection layer disposed closer to the illumination element than the liquid crystal layer.   The lighting device has a light distribution such that luminance in a direction forming an angle of 30 ° or more with respect to the normal direction of the display surface is 13% or less of luminance in the normal direction of the display surface. A liquid crystal display device according to any one of the above.   The lighting device has a light distribution such that luminance in a direction forming an angle of 30 ° or more with respect to a normal direction of the display surface is 3% or less of luminance in the normal direction of the display surface. A liquid crystal display device according to any one of the above.   The liquid crystal display device according to claim 1, wherein the illumination element includes a light source and a directivity control element that controls directivity of light emitted from the light source.

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