JP2005227753A - Liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transflective liquid crystal display having an opening filled with a transparent resin layer as a part of a color filter layer in a reflection region so as to match optical densities in a transmissive region and in the reflective region and to decrease difference in the tone between transmissive display and reflective display and to improve the display quality of the above display without reducing a color reproducing range even when a backlight using an LED is used as a light source in transmissive display and external light such as sun rays as the light source in reflective display. <P>SOLUTION: The liquid crystal display has a first substrate having transmissive pixel electrodes and reflective pixel electrodes, a liquid crystal layer, and a second substrate having a counter electrode, in this order, and has a color filter layer formed on the substrate. A pigment having a light transmission peak at 430 to 480 nm or 550 to 780 nm wavelength is dispersed by 1 to 5 mass% or 6 to 10 mass% concentration ratio in the photosensitive acrylic transparent resin which constitutes the opening formed in a part of the color filter layer in the reflective region. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a transflective liquid crystal display device. More specifically, the present invention relates to a liquid crystal display panel used for a transmissive / reflective liquid crystal display device, and more particularly to a transparent resin layer filled in an opening provided in a color filter layer.

In recent years, liquid crystal display devices have been widely used as office automation devices such as word processors and personal computers, portable information devices such as electronic notebooks, monitors for camera-integrated VTRs, etc., taking advantage of their thinness and low power consumption. . This liquid crystal display device is roughly classified into a reflection type and a transmission type according to its structure. That is, since the liquid crystal display device is not a self-luminous display device such as a CRT (CRT) or EL (electroluminescence), the transmissive type illumination device (hereinafter, referred to as a liquid crystal display panel) Display is also performed using light of “backlight”), while the reflective type is configured to perform display using ambient light.

The advantages and improvements of both of these will be explained in detail. In the case of a transmissive type, a backlight is used, so that it is less affected by ambient brightness, and a bright and high contrast ratio display is achieved. Although there is an advantage that it can be performed, the power consumption is large as much as the backlight is used, and the backlight occupies about 50% or more of the total power consumption. Furthermore, under very bright usage environments such as outdoors on a sunny day, the visibility is lowered, and the power consumption is further increased if the luminance of the backlight is increased in order to maintain the visibility.
On the other hand, in the case of the reflection type, there is an advantage that the power consumption is extremely small because the backlight is unnecessary, but the display brightness and contrast ratio are greatly influenced by the usage environment such as ambient brightness. In particular, in a dark usage environment, the visibility is extremely lowered.

Therefore, a transmissive / reflective type liquid crystal display device having a structure having a display function in both a reflective type and a transmissive type is devised in consideration of points such as power consumption and visibility while taking advantage of both. Proposed. FIG. 9 is a cross-sectional view schematically showing the configuration of the main part of the liquid crystal display panel of the transflective liquid crystal display device. As shown in FIG. 9, the transmissive / reflective liquid crystal display device includes a reflective pixel electrode 105 that reflects ambient light incident from above in each pixel and a backlight incident from below in FIG. The pixel electrode for transmission 106 that transmits the light of the light source can be used, and both display modes can be used together and the mode can be switched between transmissive display and reflective display according to the use environment (ambient brightness). Yes. Therefore, the transmissive / reflective liquid crystal display device has the advantage of low power consumption that the reflective liquid crystal display device has, and a bright and high contrast ratio display that is less affected by the ambient brightness of the transmissive liquid crystal display device. In addition, the reduction in visibility in a very bright use environment that occurs in a transmissive liquid crystal display device is reduced.

In such a transmissive / reflective liquid crystal display device, the counter electrode substrate 101 has a counter electrode 108, and the counter electrode 108 is opposed to the reflective pixel electrode 105 and the transmissive pixel electrode 106 of the TFT substrate 102. And a color filter layer 124 as a colored layer. As the color filter layer 124, the conventional transflective liquid crystal display device covers the entire transmission region T of the pixel, but the reflection region R is only partially covered. (For example, refer to Patent Documents 1 to 4.) Patent Document 1 also discloses a configuration in which the color filter layer 124 has a laminated structure of a colored layer and a transparent layer, and the colored layer in the reflective region is thinner than the colored layer in the transmissive region. With these configurations, light absorption of the color filter layer in the reflection region is reduced, and the brightness is improved. Further, in Patent Document 1, regarding the thickness of the liquid crystal layer between the front substrate and the rear substrate, the thickness Rd of the liquid crystal layer in the reflective region is ½ times the thickness Td of the liquid crystal layer in the transmissive region (Rd). = Td × 1/2) is also disclosed.

However, in such a transmissive / reflective liquid crystal display device, the light from the backlight on the back of the liquid crystal display panel is used for transmissive display, while external light such as sunlight is used for reflective display. For the calculation of the reflected chromaticity, a D65 standard light source capable of irradiating light close to the outdoor use environment is used. In this way, in the transmissive / reflective liquid crystal display device, the light source in each display method is different, so that a difference occurs in the color tone (white balance) of white display during transmissive display and reflective display. Furthermore, in recent years, the use frequency of high color temperature LEDs has increased as a backlight from the viewpoint of luminance and price. When this high color temperature LED is used as a backlight, the white balance during transmissive display is blue. While shifting in the direction, the white balance at the time of reflective display does not change greatly, so that the difference in color tone is easily recognized.
Therefore, in a transflective liquid crystal display device excellent in characteristics as a liquid crystal display device, that is, power consumption, contrast ratio, visibility, etc., by reducing the difference in color tone without reducing the color reproduction range, Furthermore, there was room for improvement in order to improve the basic performance and achieve high quality.
JP 2001-166289 A (page 1-7, FIGS. 1, 5) Japanese Patent Laid-Open No. 11-183892 (first page, FIG. 1) Japanese Patent Laid-Open No. 2002-311423 (first page, FIG. 1) JP 2003-233063 A (first page, FIG. 1)

The present invention has been made in view of the above situation, and provides a liquid crystal display device capable of reducing a difference in color tone due to a difference in light source between transmissive display and reflective display without reducing the color reproduction range. It is intended to provide.

The present inventors have examined the difference in color tone caused by the difference in the light source of a liquid crystal display device that can be used as a transmission / reflection type, and can match the optical density between transmissive display and reflective display. Therefore, attention was paid to the fact that a liquid crystal display device provided with an opening formed by filling a transparent resin in a part of the color filter layer is effective for improving the display quality. And by dispersing the pigment in the transparent resin in this opening, or providing a colored color filter layer, the color tone at the time of transmissive display and / or reflective display can be adjusted without reducing the color reproduction range. The inventors have found that the difference in color tone due to the difference in light source between the transmissive display and the reflective display can be reduced, and that the above problem can be solved brilliantly. Further, in such a liquid crystal display device, for example, each pixel has a reflective region and a transmissive region, and a blue pigment or a blue colored color filter layer is used at the opening of the color filter layer corresponding to the reflective region. Can increase the absorption of light in the long wavelength region and suppress the yellowishness of the reflection chromaticity even when the D65 light source is used for calculation of the reflection chromaticity, which effectively improves the display quality of the transflective liquid crystal display device. The present invention has been found to be improved.

That is, the present invention includes a first substrate provided with a transmissive pixel electrode and a reflective pixel electrode, a liquid crystal layer, and a second substrate provided with a counter electrode in this order, and a liquid crystal having a color filter layer formed on the substrate. In the display device, the color filter layer is provided with an opening made of a transparent resin layer in a region corresponding to the reflective pixel electrode, and the transparent resin layer has a pigment dispersed therein. This is a liquid crystal display device.
The present invention is described in detail below.

The liquid crystal display device of the present invention includes a first substrate having a transmission pixel electrode and a reflection pixel electrode, a liquid crystal layer, and a second substrate having a counter electrode in this order, and a color filter layer is formed on the substrate. It has been done. That is, in the liquid crystal display device of the present invention, a liquid crystal display panel is configured by arranging a liquid crystal layer between a first substrate having a transmissive pixel electrode and a reflective pixel electrode and a second substrate having a counter electrode. In general, peripheral members such as a driving LSI and a backlight are arranged around the liquid crystal display panel. The color filter layer is formed on at least one of the first substrate and the second substrate.
The liquid crystal display device of the present invention may or may not include other components as long as such components are essential, and is not particularly limited. The production method is not particularly limited.

The first substrate may be any substrate provided with a transmissive pixel electrode and a reflective pixel electrode. For example, an insulating layer, a transmissive pixel electrode, a reflective pixel electrode, an alignment film, etc. on a glass substrate. And the like are laminated. As the insulating layer, for example, a thin film made of SiO ₂ , SiNx or the like is preferably used. As the transmissive pixel electrode, for example, a transparent conductive film made of ITO (Indium Tin Oxide) or the like is preferably used. As the reflection pixel electrode, for example, a metal reflection film made of aluminum (Al) or the like is preferably used. As the alignment film, for example, a rubbed polyimide thin film is preferably used.

Examples of the liquid crystal layer include those made of a liquid crystal material, a spacer, and the like. As the spacer, for example, silica particles, resin particles and the like are preferably used. The liquid crystal material and the spacer are each composed of one or more materials.

The second substrate may be any substrate provided with a counter electrode, and examples thereof include a substrate in which a counter electrode and an alignment film are laminated on a glass substrate. The counter electrode is usually arranged so as to face the transmissive pixel electrode and the reflective pixel electrode. As this counter electrode, for example, a transparent conductive film made of ITO or the like is preferably used.

In the first substrate and / or the second substrate, usually three color filter layers of red, green, and blue are arranged in parallel as colored layers for each pixel. As the color filter layer, for example, a layer made of a transparent resin containing a dye or a pigment is suitable. This color filter layer is provided with an opening made of a transparent resin layer in a region corresponding to the reflective pixel electrode. That is, by providing an opening in the area of the color filter layer through which light is transmitted during reflective display, the amount of light transmitted through each color filter layer during reflective display is increased, and during transmissive display and reflective display. It is possible to match the optical densities of the two. Preferably, each of the three color filter layers arranged in parallel for each pixel is provided in a region corresponding to the reflective pixel electrode.

In the present invention, the transparent resin layer is one in which a pigment is dispersed. For example, a layer obtained by dispersing a pigment in a photosensitive acrylic resin is preferably used. Thus, by dispersing the pigment in the transparent resin layer constituting the opening, the color tone at the time of transmission display and / or reflection display is adjusted, and the difference between the color tone at the time of transmission display and the color tone at the time of reflection display is determined. It becomes possible to reduce. Since the transparent resin layer adjusts the color tone difference between the transmissive display and the reflective display, the same composition is formed for each of the red, green, and blue color filter layers as the colored layers. It is preferable. For example, a transparent resin layer in which a blue pigment is dispersed is formed also in an opening portion of a red color filter layer, and a transparent resin in which a blue pigment is dispersed in an opening portion of a blue color filter layer. A layer will be formed. In this case, in the blue color filter layer, the type, concentration, and the like of the blue pigment contained are usually different between the opening and the region other than the opening.

The pigment dispersed in the transparent resin layer is not particularly limited, and is appropriately selected according to the spectral distribution of the emitted light from the backlight that is the light source during transmissive display. For example, when a high color temperature LED is used for the backlight and an opening is provided in a part of the reflection region, a blue pigment used for a blue color filter or the like is preferably used. Are preferably those having a light transmission peak at a wavelength of 430 to 480 nm and those having high light absorption at a wavelength of 500 to 700 nm. Among these, the transparent resin layer is more preferably one in which a pigment having a light transmission peak at a wavelength of 430 to 480 nm is dispersed at a concentration ratio of 1 to 5% by mass. That is, the preferable lower limit of the concentration ratio of the pigment having a light transmission peak at a wavelength of 430 to 480 nm is 1% by mass, and the preferable upper limit is 5% by mass. By configuring the transparent resin layer in this way, the light that passes through the opening is absorbed by the pigment in the long wavelength range, and as a result, the reflective display is compared with the case where a transparent resin layer made of only transparent resin is used. The white balance at the time can be moved in the blue direction, and the color tone difference from the transmissive display when the LED having a high color temperature is used for the backlight can be reduced. If the density ratio is less than 1% by mass, the white balance at the time of reflective display may not be sufficiently moved in the blue direction. If it exceeds 5% by mass, the white balance at the time of reflective display may be moved too much in the blue direction.

In addition, as a pigment dispersed in the transparent resin layer, for example, an LED having a low color temperature is used for a backlight, and when an opening is provided in a part of a reflection region, it is used for a yellow color filter or the like. The yellow pigment is preferably used, and specifically, one having a light transmission peak at a wavelength of 550 to 780 nm or one having high light absorption at a wavelength of 380 to 500 nm is preferable. Among these, the transparent resin layer is more preferably one in which a pigment having a light transmission peak at a wavelength of 550 to 780 nm is dispersed at a concentration ratio of 6 to 10% by mass. That is, the preferable lower limit of the concentration ratio of the pigment having a light transmission peak at a wavelength of 550 to 780 nm is 6% by mass, and the preferable upper limit is 10% by mass. By configuring the transparent resin layer in this way, the light transmitted through the opening is absorbed by the pigment in the short wavelength region, and as a result, compared to the case where a transparent resin layer made of only a transparent resin is used, a reflective display is achieved. The white balance at the time can be moved in the yellow direction, and the difference in color tone from the transmissive display when the LED having a low color temperature is used for the backlight can be reduced. If the density ratio is less than 6% by mass, the white balance at the time of reflective display may not be sufficiently moved in the yellow direction. If it exceeds 10 mass%, the white balance at the time of reflective display may be moved too much in the yellow direction.

As a configuration of the liquid crystal display device of the present invention, a first substrate having a transmissive pixel electrode and a reflective pixel electrode, a second substrate, and a liquid crystal layer disposed between the first substrate and the second substrate are provided. In addition, for each pixel, a reflective region corresponding to the reflective pixel electrode and a transmissive region corresponding to the transmissive pixel electrode are formed, and at least one of the first substrate and the second substrate, It is preferable that the convex portion is formed so that the layer thickness of the liquid crystal layer in the reflective region is smaller than the layer thickness of the liquid crystal layer in the transmissive region. Since the reflective region and the transmissive region are formed for each pixel, the liquid crystal display device of the present invention can function as a transflective liquid crystal display device. In addition, by changing the thickness of the liquid crystal layer in the reflective area to be smaller than the thickness of the liquid crystal layer in the transmissive area by forming a projection for each pixel, changes in the light characteristics due to the liquid crystal layer in the reflective and transmissive areas can be achieved. You can get closer. Preferably, the thickness of the liquid crystal layer in the reflective region is ½ of the thickness of the liquid crystal layer in the transmissive region.

The present invention also includes a first substrate having a transmissive pixel electrode and a reflective pixel electrode, a liquid crystal layer, and a second substrate having a counter electrode in this order, and a liquid crystal having a color filter layer formed on the substrate. In the display device, the color filter layer has an opening formed of a transparent resin layer in a region corresponding to the reflective pixel electrode, and the transparent resin layer is opposite to the liquid crystal layer. It is also a liquid crystal display device including a colored color filter layer arranged on the side or the liquid crystal layer side.

In the liquid crystal display device, the transparent resin layer includes a colored color filter layer disposed on the side opposite to the liquid crystal layer or on the liquid crystal layer side. That is, the transparent resin layer constituting the opening provided in the color filter layer has a structure in which a layer made of a transparent resin such as a photosensitive acrylic resin and a colored color filter layer are laminated, and the colored color filter layer is liquid crystal. It is arranged on the side opposite to the layer or on the liquid crystal layer side. Thus, by setting the color filter layer on the transparent resin layer, the color tone at the time of transmissive display and / or reflective display is adjusted, and the difference between the color tone at the time of transmissive display and the color tone at the time of reflective display. Can be reduced.

The colored color filter layer is not particularly limited, and is appropriately selected according to the spectral distribution of the emitted light from the backlight, which is a light source during transmissive display, and is made of a transparent resin such as a photosensitive acrylic resin containing a dye or pigment. A thing etc. are suitable. When an LED having a high color temperature is used for the backlight and an opening is provided in a part of the reflective region, a blue colored color filter layer is preferably used. Specifically, the light has a wavelength of 430 to 480 nm. Those having a transmission peak and those having high light absorption at a wavelength of 500 to 700 nm are preferable. Especially, as for a transparent resin layer, it is more preferable that a blue coloring color filter layer is arrange | positioned by the layer thickness of 1-5% with respect to the layer thickness of a transparent resin layer. That is, the preferable lower limit of the layer thickness ratio of the blue colored color filter layer to the transparent resin layer is 1%, and the preferable upper limit is 5%. When the transparent resin layer has such a structure, the blue colored color filter layer absorbs a long wavelength region of light transmitted through the opening, and as a result, a transparent resin layer made of only a transparent resin is used. As compared with the above, the white balance at the time of reflective display can be moved in the blue direction, and the color tone difference from that at the time of transmissive display when an LED having a high color temperature is used for the backlight can be reduced. If the layer thickness ratio of the blue colored color filter layer is less than 1%, the white balance at the time of reflective display may not be sufficiently moved in the blue direction. If it exceeds 5%, the white balance during reflective display may be moved too much in the blue direction.

Further, as the colored color filter layer, when an LED having a low color temperature is used for the backlight and an opening is provided in a part of the reflective region, a yellow colored color filter layer is preferably used. Specifically, those having a light transmission peak at a wavelength of 550 to 780 nm and those having high light absorption at a wavelength of 380 to 500 nm are preferable. Especially, as for a transparent resin layer, it is more preferable that a yellow coloring color filter layer is arrange | positioned by 6-10% of layer thickness with respect to the layer thickness of a transparent resin layer. That is, the preferable lower limit of the layer thickness ratio of the yellow colored color filter layer to the transparent resin layer is 6%, and the preferable upper limit is 10%. When the transparent resin layer has such a configuration, the light transmitted through the opening is absorbed by the yellow colored color filter layer in the short wavelength region, and as a result, a transparent resin layer made of only transparent resin is used. As compared with the above, the white balance at the time of reflective display can be moved in the yellow direction, and the difference in color tone from that at the time of transmissive display when an LED having a low color temperature is used for the backlight can be reduced. If the layer thickness ratio is less than 6%, the white balance at the time of reflective display may not be sufficiently moved in the yellow direction. If it exceeds 10%, the white balance during reflection display may be moved too much in the yellow direction.

In the transparent resin layer, the colored color filter layer is disposed on the side opposite to the liquid crystal layer or on the liquid crystal layer side. When the colored color filter layer is disposed on the side opposite to the liquid crystal layer, a colored color filter layer is previously provided in the opening provided in the color filter layer, and a transparent resin such as a photosensitive acrylic resin is provided thereon. Fill. When the colored color filter layer is disposed on the liquid crystal layer side, the colored color filter layer is laminated after filling the opening with a transparent resin such as a photosensitive acrylic resin. Whether the colored color filter layer is disposed on the side opposite to the liquid crystal layer or on the liquid crystal layer side, the optical system of the transparent resin layer itself is the same. Similar effects can be obtained.

Since the liquid crystal display device of the present invention has the above-described configuration, it is possible to disperse the pigment by dispersing the pigment in the transparent resin layer constituting the opening provided in the color filter layer or by providing the colored color filter layer. The color tone at the time of display and / or reflection display can be adjusted to reduce the difference between the color tone at the time of transmissive display and the color tone at the time of reflection display. Especially, LEDs with high color temperature are used for the backlight. Even in this case, it is possible to reduce the color tone difference between the transmissive display and the reflective display, and to improve the visibility.

EXAMPLES Although an Example is hung up below and this invention is demonstrated still in detail based on drawing, this invention is not limited only to these Examples.

(Example 1)
FIG. 1-1 is a plan view schematically showing a main part of a second substrate (counter electrode substrate) in a liquid crystal display panel of a transflective liquid crystal display device of the present invention according to Examples 1 to 3, FIG. 1-2 is a plan view schematically showing the main part of the first substrate (pixel electrode substrate) facing each other. FIG. 2 is a cross-sectional view schematically showing a cross section taken along a broken line (i) in FIG. 1-1 in the liquid crystal display panel according to the first embodiment. This liquid crystal display device can display by using both the transmissive display mode and the reflective display mode.

The liquid crystal display panel of the present liquid crystal display device includes a TFT substrate 102 as a first substrate (pixel electrode substrate) having a reflective pixel electrode 105 and a transmissive pixel electrode 106 for each pixel, and a counter electrode 108. A color filter substrate (hereinafter also referred to as a “CF substrate”) 101 as a second substrate (counter electrode substrate) in which the electrode 108 is disposed so as to face the reflective pixel electrode 105 and the transmissive pixel electrode 106 of the TFT substrate 102. And. A liquid crystal layer 103 is disposed between the two substrates 101 and 102. In this liquid crystal display panel, an ECB (Electrically Controlled Birefringence) mode in which the arrangement of the liquid crystal molecules 103a is changed by an electric field and transmission and blocking of incident light are controlled using the birefringence of the liquid crystal layer 103 at that time. belongs to.

The reflective pixel electrode 105 on the TFT substrate 102 is formed of a metal reflective film made of aluminum (Al), and a region 105a of the liquid crystal layer 103 corresponding to the reflective pixel electrode 105 is a reflective used in the reflective display mode. Region R is designated. In this case, the metal reflective film made of aluminum (Al) functions as a pixel electrode. In addition to this, for example, a metal reflective film made of aluminum (Al) functioning as a reflective film may be provided as a reflective pixel electrode below a partial region of the transmissive pixel electrode. On the other hand, the transmissive pixel electrode 106 is formed of a transparent conductive film made of ITO (Indium Tin Oxide), and is connected to the end surface of the reflective pixel electrode 105 at its inner peripheral end surface. A region 106a of the liquid crystal layer 103 corresponding to the transmissive pixel electrode 106 is a transmissive region T used in the transmissive display mode. In this embodiment, the metal reflective film of the reflective pixel electrode 105 and the transparent conductive film of the transmissive pixel electrode 106 are connected in a state where the end faces are in contact with each other. You may make it the connection form with which the edge part and the edge part of a transparent conductive film were piled up. Alternatively, the reflective pixel electrode 105 may be configured by disposing the transparent conductive film also in the reflective region R and disposing a metal reflective film above or below the reflective region R portion of the transparent conductive film.

On the other hand, a color filter layer 124 is provided for each pixel on the liquid crystal layer 103 side of the CF substrate 101. In a part of the region corresponding to the reflective pixel electrode 105 of the color filter layer 124, an opening 125 as a non-colored portion (color removal portion of the color filter layer 124) penetrating the color filter layer 124 in the layer thickness direction. The opening 125 is filled with a transparent resin. A counter electrode 108 is provided on the color filter layer 124. The counter electrode 108 is also formed of a transparent conductive film made of ITO like the transmission pixel electrode 106.

The CF substrate 101 has a convex portion 127 provided so that the layer thickness Rd of the liquid crystal layer 105a in the reflection region R is smaller than the layer thickness Td of the liquid crystal layer 106a in the transmission region T (Rd <Td). . Specifically, the reflective region R portion of the counter electrode 108 is directed toward the reflective pixel electrode 105 of the TFT substrate 107 between the reflective region R portion of the color filter layer 124 and the reflective region R portion of the counter electrode 108. A transparent resin layer 128 made of a transparent resin is provided so as to be raised, and the convex portion 127 is formed by the transparent resin layer 128. Further, the opening 125 of the color filter layer 124 is constituted by a part of the transparent resin layer 128.

The transparent resin constituting the transparent resin layer 128 is a blue pigment (concentration ratio: 1.2 mass% and film thickness: 1.3 μm) with respect to the photosensitive acrylic transparent resin (acrylic negative resin): x = 0 .1
36, a color material of y = 0.140) is dispersed. By dispersing the pigment in this manner, the transparent resin layer 128 has higher light absorption in the longer wavelength region than that of the conventional transparent resin, and the light transmitted through the opening 125 is bluish. Become. As a result, the white balance at the time of reflective display can be moved in the blue direction as compared with the case of using a conventional transparent resin, and even when a high color temperature LED backlight is used, It becomes possible to reduce the color tone difference.

(Example 2)
FIG. 3 is a cross-sectional view schematically showing a cross section taken along a broken line (i) in FIG. 1-1 in the liquid crystal display panel according to the second embodiment. In the present embodiment, the transparent resin layer 128 is a layer made of a photosensitive acrylic transparent resin and a blue color filter (color material having a film thickness of 1.2 μm: x = 0.146, y = 0.176) 100. The blue color filter 100 has a stacked structure, and is disposed on the side opposite to the liquid crystal layer 103. That is, the blue color filter 100 is provided in advance in the opening 125 of the color filter layer 124, and the transparent resin layer 128 is formed by filling the photosensitive acrylic transparent resin thereon. By disposing the blue color filter 100 as the blue colored color filter layer in this manner, the transparent resin layer 128 absorbs light in a longer wavelength region than the conventional transparent resin, and the opening portion 125. The light that has passed through is bluish. As a result, the white balance at the time of reflective display can be moved in the blue direction as compared with the case where a conventional transparent resin is used, and the color tone difference from that at the time of transmissive display can be reduced. Since the other structures are the same as those in the first embodiment, description thereof is omitted here.

(Example 3)
FIG. 4 is a cross-sectional view schematically showing a cross section taken along a broken line (i) in FIG. 1-1 in the liquid crystal display panel according to the third embodiment. In the second embodiment, the blue color filter 100 is disposed on the side opposite to the liquid crystal layer 103, whereas in the present embodiment, the blue color filter (when the film thickness is 1.2 μm: x = 0.146). , Y = 0.176 color material) 100 is disposed on the liquid crystal layer 103 side. That is, the transparent resin layer 128 is formed by filling the opening 125 of the color filter layer 124 with a photosensitive acrylic transparent resin and then laminating the blue color filter 100 thereon. Since the other structures are the same as those in the second embodiment, the description thereof is omitted here. In the present embodiment, only the arrangement of the blue color filter 100 is changed with respect to the second embodiment, so that the optical system (light travel path) is the same, and the chromaticity is theoretically the same. Therefore, the same effects as those of the second embodiment are obtained.

Example 4
FIG. 5A is a plan view schematically illustrating the main part of the second substrate (counter electrode substrate) in the liquid crystal display panel of the transflective liquid crystal display device according to the fourth embodiment of the present invention. -2 is a plan view schematically showing the main part of the opposing first substrate (pixel electrode substrate). 6A is a cross-sectional view schematically showing a cross section taken along a broken line (ii) in FIG. 5A in the liquid crystal display panel according to the fourth embodiment. FIGS. It is an expanded sectional view of the opening part vicinity shown to -1. The opening shown in FIG. 6B has a structure corresponding to the first embodiment, and the opening shown in FIG. 6-3 has a structure corresponding to the second embodiment. The opening shown in FIG. 6 has a structure corresponding to the third embodiment.
This embodiment differs from the first to third embodiments in that (1) a convex portion provided to make the layer thickness Rd of the liquid crystal layer 105a in the reflection region R smaller than the layer thickness Td of the liquid crystal layer 106a in the transmission region T. 127 is formed not on the counter electrode substrate 101 side but on the pixel electrode substrate 102 side, and (2) an opening 125 provided in a part of the reflection region R of the color filter layer 124 is filled. The layer thickness of the transparent resin. That is, the convex portion 127 provided to make the layer thickness Rd of the liquid crystal layer 105a in the reflective region R smaller than the layer thickness Td of the liquid crystal layer 106a in the transmissive region T is formed on the pixel electrode substrate 102 side. The electrode substrate 101 is flat, and the layer thickness of the transparent resin filled in the opening 125 is substantially the same as that of the color filter layer 124. In addition, in order to move the white balance at the time of reflection display in the blue direction by the transparent resin layer, in FIG. 6B, the opening 125 of the color filter layer 124 is photosensitive acrylic transparent as in the first embodiment. A resin in which a blue pigment is dispersed is filled, and in FIGS. 6-3 and 4, a blue color filter 100 is laminated on a layer made of a photosensitive acrylic transparent resin as in Examples 2 and 3. ing. By these, like Example 1-3, the white balance at the time of reflective display can be moved to a blue direction rather than the case where the conventional transparent resin is used, and the color tone difference at the time of transmissive display can be reduced. It becomes possible.

(Examples 5 and 6)
Examples 1 to 4 were an example of a configuration that reduces the chromaticity difference in white balance between transmissive display and reflective display when a high color temperature LED is used as a backlight. 6 shows an example of a configuration that reduces the chromaticity difference in white balance between transmissive display and reflective display when an LED having a low color temperature is used as the backlight. That is, in Example 5, instead of the blue pigment, a yellow pigment (a color material with x = 0.449 and y = 0.466 when the density ratio is 1.2 mass% and the film thickness is 1.3 μm) is used. Except for being dispersed in the transparent resin constituting the transparent resin layer 128, the configuration is the same as that of Example 1. In Example 6, instead of the blue color filter 100, a yellow color filter (in the case of a film thickness of 1.3 μm: a color material of x = 0.449, y = 0.466) is used as the transparent resin layer 128. Except for being included, the configuration is the same as in the second embodiment.
Normally, when an LED with a low color temperature is used as the backlight, the white balance at the time of transmissive display shifts in the yellow direction, while the white balance at the time of reflective display does not change greatly, so that the difference in color tone is recognized. . However, according to the configuration of Example 5 or 6, the transparent resin layer 128 has higher light absorption in a short wavelength region than that of the conventional transparent resin, and the light passing through the opening 125 is yellow. It will have a taste. As a result, the white balance at the time of reflective display can be moved in the yellow direction compared to the case of using a conventional transparent resin, and even when an LED backlight having a low color temperature is used, It is possible to reduce the color tone difference.

(Evaluation-chromaticity simulation)
The chromaticity coordinates x and y in the XYZ color system for white display were simulated for the transflective liquid crystal display device of the present invention according to Examples 1 and 4. As a procedure for the simulation, first, the chromaticity coordinates x and y of the white display at the time of transmissive display were calculated for the LED having a high color temperature (manufactured by Nichia) and the LED having a slightly high color temperature (manufactured by Nichia). . Next, while changing the blending ratio of the blue pigment dispersed in the transparent resin layer (when the concentration ratio is 1.2 mass% and the film thickness is 1.3 μm: x = 0.136, y = 0.140 color material) The chromaticity coordinates x and y of the white display at the time of reflection display using the D65 standard light source were calculated. And each chromaticity coordinate x and y was plotted and compared. The result is shown in FIG.
Similarly, the chromaticity coordinates x and y in the XYZ color system for white display were simulated for the transflective liquid crystal display device of the present invention according to Example 5. As a point of the simulation, first, chromaticity coordinates x and y of white display at the time of transmissive display were calculated for the LED having a low color temperature and the LED having a slightly low color temperature. Next, while changing the blending ratio of the yellow pigment dispersed in the transparent resin layer (when the concentration ratio is 1.2% by mass and the film thickness is 1.3 μm: x = 0.449, y = 0.466 colorant) The chromaticity coordinates x and y of the white display at the time of reflection display using the D65 standard light source were calculated. And each chromaticity coordinate x and y was plotted and compared. The result is shown in FIG.

As shown in FIG. 7, as the blending ratio of the blue pigment increases, the chromaticity coordinates x and y of the white display at the time of reflection display become small, and the white balance moves in the blue direction. Here, chromaticity coordinates x, y of white display at the time of reflective display, and chromaticity coordinates x, y of white display at the time of transmissive display when an LED having a high color temperature or an LED having a slightly high color temperature is used as a backlight. When the ratio of the blue pigment blended in order to match y was read from FIG. 7, it was found to be 1 to 5% by mass.
Further, as shown in FIG. 8, as the blending ratio of the yellow pigment increases, the chromaticity coordinates x and y of the white display during the reflective display increase, and the white balance moves in the yellow direction. It was. Here, chromaticity coordinates x, y of white display at the time of reflective display, and chromaticity coordinates x, y of white display at the time of transmissive display when an LED having a low color temperature or an LED having a slightly low color temperature is used as a backlight. When the ratio of the yellow pigment blended to match y was read from FIG. 8, it was found to be 6 to 10% by mass.

Therefore, actually, the transflective liquid crystal display device of the present invention according to Examples 1 to 4 and 6 and the transflective liquid crystal display device according to Comparative Examples 1 to 4 corresponding to Examples 1 to 4 and 6 are used. The chromaticity coordinates x and y and the color reproduction range (NTSC ratio) of white display during transmission display and reflection display were calculated. Specifically, in Example 1, a transparent resin layer 128 in which a blue pigment is dispersed in a photosensitive acrylic transparent resin at a concentration ratio of 1.2% by mass is used, and in Comparative Example 1, a blue pigment is dispersed. Transparent resin layer 128 is used, and the area ratio of the opening 125 in the reflection region R of each of the red, green, and blue color filter layers 124 is red / green / blue = 21% / 43% / 16%. . In the calculation according to Example 1, it was assumed that a high color temperature (blue) LED (manufactured by Nichia Chemical) was used as a light source (backlight) during transmissive display. In Examples 2 and 3, the transparent resin layer 128 in which the blue color filter 100 is laminated with a thickness of 0.06 μm (1.3% of the thickness of the transparent resin layer) is used. In Comparative Example 2, the blue color filter is used. The transparent resin layer 128 on which the filter 100 is not laminated is used, and the area ratio of the opening 125 in the reflection region R of each of the red, green, and blue color filter layers 124 is red / green / blue = 17% / 31%. / 9%. In Example 4, the transparent resin layer 128 obtained by laminating the blue color filter 100 with a thickness of 0.04 μm (2.2% of the thickness of the transparent resin layer) is used. In Comparative Example 3, the blue color filter 100 is used. Is used, and the area ratio of the opening 125 in the reflection region R of each of the red, green and blue color filter layers 124 is red / green / blue = 17% / 31% / 9. %. In the calculations according to Examples 2 to 4, it was assumed that an LED (manufactured by Nichia) having a slightly higher color temperature (slightly blue) was used as a light source (backlight) during transmissive display. In Example 6, the yellow color filter 100 has a thickness of 0.225 μm (6% of the thickness of the transparent resin layer: Example 6-1) or a thickness of 0.4 μm (10% of the thickness of the transparent resin layer: Example). 6-2) is used, and in Comparative Example 4, the transparent resin layer 128 without the yellow color filter 100 is used, and the red, green, and blue color filter layers are used. The area ratio of the opening 125 in the reflection region R of 124 was red / green / blue = 20% / 30% / 10%. In the calculation according to Example 6-1, it is assumed that a slightly low (slightly yellow) LED (manufactured by Nichia Chemical) having a low color temperature is used as a light source (backlight) during transmissive display. In the calculation according to -2, it was assumed that a LED having a low color temperature (yellow) (manufactured by Nichia) was used as a light source (backlight) during transmissive display. The results are shown in Tables 1 and 2.

As shown in Table 1, by using a blue or yellow pigment or a blue or yellow color filter 100 for the transparent resin layer 128, the color tone difference in white display between transmissive display and reflective display is reduced. In addition, the NTSC ratio is not reduced, and there is an effect of suppressing a deterioration in display quality due to a color tone difference between white display and transmissive display.
In the above-described embodiment, the configuration in which the pixel electrode for reflection and the pixel electrode for transmission exist for each pixel has been described. However, the present invention is not limited to such a configuration. For example, the transmissive pixel electrode has a stripe shape extending in the lateral direction across a plurality of pixels, the reflective pixel electrode is disposed below the transmissive pixel electrode in a partial region of the pixel, and the counter electrode is A configuration in which the pixel is patterned into a shape defining the pixel is also included in the present invention.

It is the top view which showed typically the structure of the principal part of the 2nd board | substrate (counter electrode board | substrate) in the liquid crystal display panel of the transflective liquid crystal display device of this invention which concerns on Examples 1-3. It is the top view which showed typically the structure of the principal part of the 1st board | substrate (pixel electrode substrate) in the liquid crystal display panel of the transflective liquid crystal display device of this invention which concerns on Examples 1-3. 1 is a cross-sectional view schematically showing a cross section taken along a broken line (i) in FIG. 1-1 in a liquid crystal display panel according to Example 1. FIG. It is sectional drawing which showed typically the cross section in the broken line (i) of FIGS. 1-1 in the liquid crystal display panel which concerns on Example 2. FIG. It is sectional drawing which showed typically the cross section in the broken line (i) of FIGS. 1-1 in the liquid crystal display panel which concerns on Example 3. FIG. FIG. 10 is a plan view schematically showing a main part of a second substrate (counter electrode substrate) in a liquid crystal display panel of a transflective liquid crystal display device of the present invention according to Example 4. FIG. 10 is a plan view schematically showing a main part of a first substrate (pixel electrode substrate) in a liquid crystal display panel of a transflective liquid crystal display device of the present invention according to Example 4. FIG. 5 is a cross-sectional view schematically showing a cross section taken along a broken line (ii) in FIG. 5A in a liquid crystal display panel according to Example 4; It is an expanded sectional view of the opening part vicinity shown to FIGS. The opening has a structure corresponding to the first embodiment. It is an expanded sectional view of the opening part vicinity shown to FIGS. The opening has a structure corresponding to the second embodiment. It is an expanded sectional view of the opening part vicinity shown to FIGS. The opening has a structure corresponding to the third embodiment. D65 standard while changing chromaticity coordinates x and y for white display and transmission ratio of blue pigment dispersed in transparent resin layer at the time of transmissive display using LED with high color temperature and LED with slightly higher color temperature as light source It is the graph which compared and showed the simulation result with chromaticity coordinates x and y of white display at the time of reflective display using a light source. D65 standard while changing chromaticity coordinates x, y for white display and transmission ratio of yellow pigment dispersed in transparent resin layer in transmissive display using LED with low color temperature and LED with slightly low color temperature as light source It is the graph which compared and showed the simulation result with chromaticity coordinates x and y of white display at the time of reflective display using a light source. It is sectional drawing which showed typically the structure of the principal part in the liquid crystal display panel of the conventional transflective liquid crystal display device.

Explanation of symbols

100: Color filter (blue or yellow) 101: Second substrate (color filter substrate)
102: First substrate (TFT substrate)
103: Liquid crystal layer 103a: Liquid crystal molecule 105: Reflection pixel electrode 105a: Liquid crystal layer 106 in the reflection region 106: Transmission pixel electrode 106a: Liquid crystal layer 108 in the transmission region 108: Counter electrode 119: Insulating layer 122: Alignment film 123: Glass substrate 124: Color filter layer 125: Opening part 126: Part where the color filter layer is cut out 127: Convex part 128: Transparent resin layer 129: Black matrix (BM)
130: Source bus line 131: Gate bus line 132: CS electrode T: Transmission region R: Reflection region Td: Layer thickness of liquid crystal layer in transmission region Rd: Layer thickness of liquid crystal layer in reflection region

Claims (6)

A liquid crystal display device having a first substrate having a transmissive pixel electrode and a reflective pixel electrode, a liquid crystal layer, and a second substrate having a counter electrode in this order, and a color filter layer formed on the substrate. ,
The color filter layer is provided with an opening made of a transparent resin layer in a region corresponding to the reflective pixel electrode.
The transparent resin layer is a liquid crystal display device in which a pigment is dispersed. 2. The liquid crystal display device according to claim 1, wherein the transparent resin layer comprises a pigment having a light transmission peak at a wavelength of 430 to 480 nm dispersed in a concentration ratio of 1 to 5 mass%. 2. The liquid crystal display device according to claim 1, wherein the transparent resin layer comprises a pigment having a light transmission peak at a wavelength of 550 to 780 nm dispersed in a concentration ratio of 6 to 10% by mass. A liquid crystal display device having a first substrate having a transmissive pixel electrode and a reflective pixel electrode, a liquid crystal layer, and a second substrate having a counter electrode in this order, and a color filter layer formed on the substrate. ,
The color filter layer is provided with an opening made of a transparent resin layer in a region corresponding to the reflective pixel electrode.
The liquid crystal display device, wherein the transparent resin layer includes a colored color filter layer disposed on the side opposite to the liquid crystal layer or on the liquid crystal layer side. 5. The liquid crystal display device according to claim 4, wherein the transparent resin layer is a layer in which a blue colored color filter layer is disposed with a layer thickness of 1 to 5% with respect to the layer thickness of the transparent resin layer. 5. The liquid crystal display device according to claim 4, wherein the transparent resin layer is a layer in which a yellow colored color filter layer is disposed with a layer thickness of 6 to 10% with respect to a layer thickness of the transparent resin layer.

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