JP4325631B2 - Display device and electronic device using the same - Google Patents

Description

  The present invention relates to a display device and an electronic apparatus using the display device, and more particularly to a transflective type that can be used both as a reflective display device that reflects external light and performs display, and a transmissive type that transmits light and transmits light. The present invention relates to a display device that performs reflective display and an electronic apparatus using the display device.

  Conventionally, display devices using a liquid crystal panel include a reflective type that performs display using external light and a transmissive type that emits light from the back surface of the liquid crystal panel. Here, in the case of a reflective display device, the amount of external light decreases in a dark place, so that the display becomes difficult to see. On the other hand, in the case of a transmissive display device, the power consumption is increased by the amount of the light source regardless of whether it is a bright place or a dark place, and is not particularly suitable for a portable display device operated by a battery.

  Thus, there is a transflective display device that can be used for both a reflective type and a transmissive type. In this display device, when used in a bright place, an optical element such as a liquid crystal or a polarizing plate arranged on the optical path is reflected while reflecting external light incident from the display screen by a light reflecting plate provided inside the device. The amount of light emitted from the display screen is controlled for each pixel to perform reflective display.

  On the other hand, when the display device is used in a dark place, the light source light is irradiated from the back side of the liquid crystal panel by a built-in light source such as a backlight, and the display is performed using the optical elements such as the liquid crystal and the polarizing plate. The transmissive display is performed by controlling the amount of light emitted from the screen for each pixel.

  In the display device, the liquid crystal filled in the liquid crystal panel uses TN (Twisted Nematic) liquid crystal, STN (Super-Twisted Nematic) liquid crystal, or the like, and the polarization axis of the liquid crystal depends on the presence or absence of a voltage applied to the pixel. Is rotated to make the transmission polarization axis variable.

  In addition, the present inventors use the reflective polarizing plate that reflects light having a linearly polarized light component in a predetermined direction and transmits light having a linearly polarized light component in a direction substantially perpendicular to the polarizing plate. Japanese Patent Application No. 11-023719 filed an application for improving the brightness at the time of mold display (hereinafter referred to as prior art).

  Further, when performing color display, a color filter is provided on the inner surface of the liquid crystal panel, and the reflected light is colored by passing through the color filter to perform color display.

  However, in the display device according to the above-described prior art, when the reflective display is performed, when incident light is reflected by the light reflection plate and emitted, the display device is short by a member sandwiched between the liquid crystal panel and the light reflection plate. The wavelength component is absorbed and colored yellow. Furthermore, since various polarizing members are sandwiched between the liquid crystal panel and the light reflecting plate, this thickness is increased, and light having a short wavelength component is absorbed more by this thickness, and incident light is absorbed. Will be colored yellowish.

  For this reason, when color display is performed by a display device, there is a problem that a yellowish color is displayed and a clear color display cannot be performed.

  The present invention has been made in view of the above-described circumstances, and a display device capable of realizing a bright and vivid color display regardless of whether the display mode is a reflective display or a transflective display, and uses the display device. The purpose is to provide electronic devices.

Display device of the present invention in order to achieve the above object, a red color system, a liquid crystal panel provided with a color filter having a colored region greenish and blue is provided on the rear side of the liquid crystal panel, translucent a lighting device to sexual light guide and light guide member having a deployable light source light, and the liquid crystal panel of the illumination device provided on the opposite side of a light reflection plate for reflecting external light, wherein A polarizing plate provided on the opposite side of the light reflecting plate of the liquid crystal panel, a transmissive display by light from the lighting device, and a reflective type by the external light reflected from the light reflecting plate. Display is possible, the white point is (0.310, 0.316), and the chromaticities of the red, green, and blue colored regions are R (xr, yr), G (xg, yg) and B (x b , y b ), the distance between the white point and R, white When the distance between the point and G and the distance between the white point and B are Rr, Rg, and Rb, respectively, the light emitted from the polarizing plate through the light guide is prevented from being colored. Thus, 1.6 <Rr / Rg <3.8 and 1.6 <Rb / Rg <3.8 are satisfied. Further, it is preferable that a light diffusing plate having a forward scattering characteristic is further provided so that the light passing through the color filter is diffused by the light diffusing plate. Moreover, you may provide the 1st polarizing means provided in the upper side of the liquid crystal panel and isolate | separating incident light according to the polarization component.

According to the display device of the present invention, by setting the chromaticity of each color of the color filter as described above, coloring by the light guide provided between the liquid crystal panel and the light reflection plate is prevented, and the display device is provided. It is possible to prevent the light emitted from the device from being yellowish and colored and to perform a clear color display.

  Further, it is preferable that a second polarizing means for separating incident light according to the polarization component is provided between the liquid crystal panel and the light reflecting means.

  By doing so, the external light transmitted through the liquid crystal panel is polarized and separated by the second polarizing means, thereby performing bright and dark display.

  As the second polarizing means, a polarizing means that substantially transmits the light of the first linearly polarized light component and substantially absorbs the light of the second linearly polarized light component substantially orthogonal to the one linearly polarized light component is adopted. preferable.

By adopting such a polarizing means, the dark light is displayed by absorbing the external light transmitted through the liquid crystal panel by the second polarizing means, and the bright display is obtained by transmitting the light to the second polarizing means and then reflecting it. Therefore, a display with extremely excellent contrast characteristics can be realized.
Also, a second linearly polarized light provided between the second polarizing means and the light reflecting means, substantially transmits the light of the first linearly polarized component and is substantially orthogonal to the one linearly polarized component. It is preferable that a reflection polarizer that substantially reflects the component light is provided, and that the transmission axis of the reflection polarizer and the transmission axis of the second polarizing means are substantially coincident.

  With this configuration, light having a polarization direction equal to the transmission axis direction of the reflective polarizer among the incident light is transmitted through the reflective polarizer. On the other hand, light having a polarization direction equal to the reflection axis of the reflective polarizer is reflected by the reflective polarizer. Then, it is reflected by the light reflecting means and returns to the reflective polarizer again. And while repeating this reflection, any of them will pass through the reflective polarizer. That is, most of the incident light is emitted toward the second polarizing means as light having a polarization direction equal to the transmission axis direction of the reflective polarizer. Then, the light passes through the second polarizing means whose transmission axis is set parallel to the transmission axis of the reflective polarizer and is emitted toward the liquid crystal panel. As a result, a reflective display with very good utilization efficiency of incident light is realized.

  The second polarizing means is a reflective polarizer that substantially transmits the light of the first linearly polarized light component and substantially reflects the light of the second linearly polarized light component that is substantially orthogonal to the one linearly polarized light component. It is preferable.

  Furthermore, according to the other aspect of this invention, it is further equipped with the illuminating device which has a translucent light guide and the light source which can introduce light into this light guide, The said illuminating device is the said light-diffusion means. And the light reflecting means.

  The display device according to the present invention relates to a so-called transflective display device that can perform transmissive display using light source light when dark and can perform reflective display using external light when bright. According to the display device of this aspect, a transflective display device capable of reflective display without parallax or color mixing is realized. Furthermore, since light emitted from the light source is sufficiently diffused by the light diffusing means having forward scattering characteristics even in the transmissive display, the liquid crystal panel can be irradiated with light uniformly.

  An electronic apparatus according to the present invention includes the display device described above.

  According to the electronic apparatus of the present invention, it is possible to realize color display without color mixing.

  Next, the display principle of the display device according to the present invention will be described in detail with reference to FIGS. Although an example of a transflective display device is shown below, the reflective display principle does not change even in a reflective display device.

  In this liquid crystal display device, a TN liquid crystal panel 140 is used as a transmission polarization axis variable optical element. Further, an upper polarizing plate 130 is provided on the upper side of the TN liquid crystal panel 140, and a color filter 150 made of RGB (red, green, blue), a lower polarizing plate 160, and light are provided on the lower side of the TN liquid crystal panel 140. A diffusion plate 170 and a reflective polarizing plate 180 are sequentially provided. Further, a backlight 190 serving as a light source and a light reflecting plate 200 are sequentially provided below the reflective polarizing plate 180.

  The transmission axis of the upper polarizing plate 130 and the transmission axis of the lower polarizing plate 160 are substantially orthogonal to each other, and the transmission axis of the lower polarizing plate 160 and the transmission axis of the reflective polarizing plate 180 are parallel to each other. The light diffusing plate 170 performs forward scattering having a haze value H.

  Further, 141 on the left side indicates a voltage non-application area where no voltage is applied to the TN liquid crystal panel 140, and 142 on the right side indicates a voltage application area where a voltage is applied.

  With respect to the display device configured as described above, the operation of the reflective display will be described with reference to FIG.

  First, a case where light incident from the outside passes through the no-voltage application region 141 of the TN liquid crystal panel 140 will be described.

  The incident light 111 incident from the outside of the display device is transmitted only by the upper polarizing plate 130 with light having a linearly polarized component in the direction parallel to the paper surface, and then this light is applied by the voltage non-application region 141 of the TN liquid crystal panel 140. Light having a linearly polarized light component in a direction perpendicular to the plane of the paper whose polarization direction is twisted by approximately 90 °, and the color filter 150, the lower polarizing plate 160, the light diffusion plate 170, and the reflective polarizing plate 180 are straight in the direction perpendicular to the paper surface. The light is transmitted as a polarization component, passes through the transparent backlight 190, reaches the light reflection plate 200, and is reflected. Of the light reflected by the light reflecting plate 200, only the light 112 having the linearly polarized component in the direction perpendicular to the paper surface is again the backlight 190, the reflective polarizing plate 180, the light diffusing plate 170, the lower polarizing plate 160, the color. The light is transmitted through the filter 150 and twisted by about 90 ° by the no-voltage application region 141 to have light having a linearly polarized component in a direction parallel to the paper surface, and this light is emitted as emitted light 113.

  The light reflected by the light reflecting plate 200 includes not only light 112 having a linearly polarized component in a direction perpendicular to the paper surface but also light 114 having a linearly polarized component in a direction parallel to the paper surface. For this reason, the light 114 is reflected by the reflective polarizing plate 180, is reflected again by the light reflecting plate 200, the polarization direction is changed, and the light 114 has a linearly polarized light component whose direction is perpendicular to the paper surface. Passes through the reflective polarizing plate 180. By repeating this, light can be used effectively, and the outgoing light 113 emitted from the upper polarizing plate 130 can be brightened by about 1.6 times as compared with the case where the reflective polarizing plate 180 is not used. .

  Here, although the incident light 111 and the outgoing light 113 appear to pass through the color filters 150 having different colors, the light diffusion plate 170 is provided between the lower polarizing plate 160 and the reflective polarizing plate 180. When passing through the light diffusion plate 170, the light passing through the color filters 150 of each color is diffused. For this reason, the light reflected by the light reflecting plate 200 is not mixed with red, green, and blue, and a specific color is not strongly colored. As a result, the light 113 emitted from the upper polarizing plate 130 is colored in the color of the color filter 150 through which the light reflected by the light reflecting plate 200 passes.

  Next, a case where light incident from the outside passes through the voltage application region 142 of the TN liquid crystal panel 140 will be described.

  Of the incident light 116 incident from the outside of the display device, only light having a linearly polarized component in a direction parallel to the paper surface is transmitted by the upper polarizing plate 130, and then this light is polarized by the voltage application region 142 of the TN liquid crystal panel 140. It passes without changing its direction, passes through the color filter 150, is absorbed by the lower polarizing plate 160 and becomes dark.

  As described above, in the no-voltage application region 141, the light incident on the display device can be effectively used by the reflective polarizing plate 180, and the light reflected by the light reflecting plate 200 is colored by the color filter 150. 113 is emitted. On the other hand, in the voltage application region 142, light is absorbed by the lower polarizing plate 160 and becomes dark.

  Next, the operation of the transmissive display will be described with reference to FIG.

  First, the case where the light emitted from the backlight 190 passes through the no-voltage application region 141 of the TN liquid crystal panel 140 will be described.

  Of the light source light generated from the backlight 190, the light 121 having a linearly polarized component in the direction perpendicular to the paper surface passes through the reflective polarizing plate 180, the light diffusing plate 170, the lower polarizing plate 160, and the color filter 150, and TN. The voltage non-application region 141 of the liquid crystal panel 140 becomes light having a linearly polarized component in a direction parallel to the plane of the paper whose polarization direction is twisted by approximately 90 °, and this light is emitted from the upper polarizer 130 as emitted light 122.

  The light source light from the backlight 190 includes not only light 121 having a linearly polarized component in a direction perpendicular to the paper surface but also light 123 having a linearly polarized component in a direction parallel to the paper surface. Therefore, the light 123 is reflected by the reflective polarizing plate 180, reflected by the light reflecting plate 200, the polarization direction is changed, and part of the light 123 is reflected as light 124 having a linearly polarized component in a direction perpendicular to the paper surface. Passes through the polarizing plate 180. By repeating this, light can be used effectively and the emitted light 122 can be brightened.

  Next, the case where the light source light from the backlight 190 passes through the voltage application region 142 of the TN liquid crystal panel 140 will be described.

  Of the light source light of the backlight 190, the light 125 having a linearly polarized component in a direction perpendicular to the paper surface passes through the reflective polarizing plate 180, the light diffusing plate 170, the lower polarizing plate 160, and the color filter 150, and then this light. Passes through the voltage application region 142 of the TN liquid crystal panel 140 without changing the polarization direction, and is absorbed by the upper polarizing plate 130 and becomes dark.

  Of the light source light from the backlight 190, the light 126 having a linearly polarized component in a direction parallel to the paper surface is reflected by the reflective polarizing plate 180 and reflected by the light reflecting plate 200 to change the polarization direction. The light becomes a light 127 having a linearly polarized light component whose direction is perpendicular to the paper surface, and passes through the reflective polarizing plate 180. However, the light 127 also passes through the voltage application region 142 of the TN liquid crystal panel 140 without changing the polarization direction, and is absorbed by the upper polarizing plate 130 and becomes dark.

  Thus, the emitted light 113 and 122 colored by the color filter 150 is emitted by the combination of voltage application / non-application of the TN liquid crystal panel 140.

  Moreover, in the display device according to the present invention, the light diffusing plate 170 and the light reflecting plate 200 are provided, so that the light having the linearly polarized component in the direction parallel to the paper surface, like the incident light 111 shown in FIG. By passing, for example, red of the color filter 150, the light is colored red and passes through the lower polarizing plate 160, the light diffusing plate 170, the reflective polarizing plate 180, and the backlight 190, and reaches the light reflecting plate 200. Since the red light is scattered forward when passing through the light diffusion plate 170, the light reaching the light reflection plate 200 passes not only the light passing through the red color filter 150 but also green and blue. The light that has undergone green and blue coloring will be mixed and approach white light. For this reason, the light 112 reflected by the light reflecting plate 200 seems to be red in FIG. 2, but substantially receives the coloring of other colors (green, blue) diffused by the light diffusing plate 160. Since the reflected light is reflected in the same manner, the reflected light is white. Then, the white light passes through the backlight 190, the reflective polarizing plate 180, the light diffusing plate 170, and the lower polarizing plate 160 again and passes through a specific color (for example, green) among the color filters 150, and the liquid crystal panel 140. The light emitted through the upper polarizing plate 130 is colored green.

  In addition, since the light diffusing plate 170 and the light reflecting plate 200 are provided in the display device according to the present invention, the light having the linearly polarized component in the direction parallel to the paper surface, such as the incident light 111 shown in FIG. By passing, for example, red of the filter 150, the filter 150 is colored red and passes through the lower polarizing plate 160, the light diffusing plate 170, the reflective polarizing plate 180, and the backlight 190, and reaches the light reflecting plate 200. Since the red light is scattered forward when passing through the light diffusion plate 170, the light reaching the light reflection plate 200 passes not only the light passing through the red color filter 150 but also green and blue. Therefore, it is desirable that the light which received the coloring of green and blue mixed, and to approach white light. However, a lower polarizing plate 160, a light diffusing plate 170, a reflective polarizing plate 180, a backlight 190, and the like are disposed between the color filter 150 and the light reflecting plate 200. For this reason, since the liquid crystal panel 140 and the light reflection plate 200 are separated from each other, light having a short wavelength component is absorbed, and the light reflected from the light reflection plate 200 is colored yellowish. Further, the member interposed between the TN liquid crystal panel 140 and the reflective polarizing plate 180, the color filter 150, the lower polarizing plate 160, the light diffusing plate 170, the reflective polarizing plate 180 and the backlight 190 are colored yellowish. Therefore, the light is also colored yellow.

  Therefore, the present inventor measured the chromaticity of the color filter 150 that causes such a problem and the chromaticity in the display color of the TN liquid crystal panel 140 that received the reflected light. As a result, the results shown in Table 1 below were obtained. Got.

  The separation dimension R in the table indicates the distance from the white point (0.310, 0.316) to the chromaticities R, G, and B of the red, green, and blue color filters.

When the coordinates of chromaticity when measured with a C light source are R (xr, yr), G (xg, yg), and B (xb, yb), the separation dimensions Rr, Rg, Rb are: Rr = {(xr −0.310) ² + (yr−0.316) ² } ^1/2 Rg = {(xg−0.310) ² + (yg−0.316) ² } ^1/2 Rb = {(xb−0) .310) ² + (yb−0.316) ² } ^1/2 .

  Thus, since the white coordinates on the liquid crystal panel 140 are (0.326, 0.358), they are colored lighter in terms of chromaticity than the standard white coordinates (0.310, 0.316). I understood.

Therefore, the inventor sets the chromaticity of the color filter 150 and repeats various experiments in order to make the light reflected by the light reflection plate 200 close to the white coordinate, for example, in the following Tables 2 and 3. The color filter designed in this way was detected to approach the white coordinate.

  Furthermore, it has been found that the chromaticity setting of each color of the color filter may be set so as to satisfy the following formula (1).

1.6 <Rr / Rg <3.8 and 1.6 <Rb / Rg <3.8 (1)
Here, the results of Tables 1 to 3 are shown in FIG.

  4A is a chromaticity diagram of a color filter, and FIG. 4B is a chromaticity diagram of display colors. W0 is a white point (0.310, 0.316), W1 is a white display coordinate according to the prior art, W2 is a white display coordinate obtained by Table 2, and W3 is a white display coordinate obtained by Table 3. Show.

  As can be seen from FIG. 4B, the white display coordinate W1 according to the prior art is out of the white region, but by increasing the values of Rr / Rg and Rb / Rg to be larger than 1.6, The white display coordinates enter the white area and approach the white point W0. As the display size further increases, the white display coordinates approach the white point W0, but when Rr / Rg> 3.8 or Rb / Rg> 3.8, the coordinates of R, G, B are in the white region. The red R and blue B cannot be displayed. For this reason, the range of said numerical formula (1) is set.

  Then, by setting the chromaticity of each color of the color filter, when the reflective display is performed in the display device according to the present invention, the reflected light incident on the color filter 150 can be made white and emitted from the display device. It is possible to prevent the light from being colored yellowish and to display a clear color.

  Further, if the color filter 150 is a dot matrix display composed of red, green, and blue, multicolor display and further full color display are possible.

  In the above description, the normally white mode has been described, but a normally black mode may be used. Moreover, in the normally white mode, there is an effect that the display becomes brighter in both cases of the reflective display and the transmissive display.

  In the display device having the above-described configuration, the transflective liquid crystal display device using the backlight 190 has been illustrated. However, the present invention is not limited thereto, and the present invention may be applied to a reflective liquid crystal display device in which the backlight 190 is omitted. Of course it is good.

  Next, the principle of the reflective polarizing plate will be described with reference to FIGS. FIG. 1 is a schematic perspective view of a reflective polarizing plate serving as a reflective polarizing means, and FIGS. 2 and 3 are schematic views of a display device using the reflective polarizing plate.

  First, the structure of the reflective polarizing plate 180 will be described with reference to FIG. The reflective polarizing plate 180 has a laminated structure in which two different layers 1 (A layer) and 2 (B layer) are alternately laminated. Here, in the layers 1 and 2, the refractive index (nAY) in the Y direction of the A layer 1 and the B layer 2 are different from the refractive index (nAX) in the X direction and the refractive index (nAY) in the Y direction of the A layer 1. Is formed so as to be substantially equal to the refractive index (nBY) in the Y direction.

Therefore, light having a linearly polarized light component in the Y direction out of light incident on the reflective polarizer 180 from a direction perpendicular to the upper surface 5 of the reflective polarizer 180 is transmitted through the reflective polarizer 180 and transmitted in the Y direction from the lower surface 6. It is emitted as light having a linearly polarized light component. Conversely, light having a linearly polarized light component in the Y direction out of light incident on the reflective polarizer 180 from a direction perpendicular to the lower surface 6 of the reflective polarizer 180 is transmitted through the reflective polarizer 180 and transmitted from the upper surface 5 to the Y direction. Is emitted as light having a linearly polarized light component. Here, the direction in which light is transmitted (Y direction) is referred to as a transmission axis. On the other hand, when the thickness of the A layer 1 in the Z direction is tA, the thickness of the B layer 2 in the Z direction is tB, and the wavelength of the incident light is λ,
tA · nAX + tB · nBX = λ / 2 (2)
The reflective polarizing plate 180 is formed so as to satisfy the above.

  As a result, light having a linearly polarized component in the X direction out of light having a wavelength λ incident on the reflective polarizer 180 from a direction perpendicular to the upper surface 5 of the reflective polarizer 180 is reflected by the reflective polarizer 180. . In addition, light having a linearly polarized light component in the X direction out of light incident on the reflective polarizing plate 180 from a direction perpendicular to the lower surface 6 of the reflective polarizing plate 180 is reflected by the reflective polarizing plate 180. Here, the direction in which light is reflected (X direction) is referred to as a reflection axis.

  Then, the reflective polarizing plate 180 varies the thickness tA in the Z direction of the A layer 1 and the thickness tB in the Z direction of the B layer 2 to satisfy the above formula (2) over the entire wavelength range of visible light. Thus, not only a single color but also the light having the X direction linearly polarized light is reflected as the light having the X direction linearly polarized light over the entire white light, and the light having the Y direction linearly polarized light is reflected by the Y direction linearly polarized light. It will be transmitted as light having.

  For example, a layer obtained by stretching polyethylene naphthalate (PEN) is used for the A layer of the reflective polarizing plate 180, and a copolyester (coPEN; copolyester) of naphthalene dicarboxylic acid and terephthalic acid is used for the B layer. of naphthalene dicarboxylic acid and terephthalic or isothalic acid). In addition, the material of the reflective polarizing plate 180 used for this invention is not limited to this, The material can be selected suitably. The details of such a reflective polarizing plate are disclosed as a reflective polarizer in, for example, JP-T-9-506985.

  Next, an embodiment of the present invention will be described with reference to the drawings.

1. Embodiment <First Embodiment>
FIG. 5 is a schematic configuration diagram of the color display device 10 according to the first embodiment. The display device 10 uses the STN cell 20 as a transmission polarization axis varying unit. In addition, the retardation film 14 and the upper polarizing plate 12 are sequentially provided on the upper side of the STN cell 20, and the light diffusion plate 30 and the lower polarizing plate 15 are sequentially provided on the lower side of the STN cell 20. A reflective polarizing plate 40, a light source 70, and a light reflecting plate 60 are sequentially provided below the lower polarizing plate 15.

  Here, the light source 70 uses an LED (Light Emitting Diode) 71, and the light guide 72 emits light upward. The light guide 72 is formed to a thickness of about 0.7 mm by a transparent resin such as acrylic resin, polycarbonate resin, and amorphous polyolefin resin, an inorganic transparent material such as glass, or a composite thereof. In addition, a plurality of small protrusions are formed on the surface of the light guide 72, and the size of each protrusion is such that the wavelength of visible light is about 380 nm to 700 nm. About 5 μm or more is necessary, and 300 μm or more is desirable for the size of the projections to be invisible to the naked eye.

  Further, the light reflecting plate 60 is made of aluminum film or silver film deposited on a PET film, aluminum foil or the like.

  Further, the STN cell 20 is configured by a liquid crystal panel having a configuration in which an STN liquid crystal 26 is sealed in a cell including two glass substrates 21 and 22 and a seal member 23. A transparent electrode 24 is formed on the lower surface of the glass substrate 21 and a transparent electrode 25 is provided on the upper surface of the glass substrate 22 to constitute a dot matrix. The transparent electrodes 24 and 25 are made of ITO (Indium Tin Oxide), tin oxide, or the like. Further, a color filter 27 made of red 27R, green 27G, and blue 27B is formed on the lower surface of the transparent electrode 24, and matches the electrode pattern of the transparent electrode 25. The color filter 27 may be formed between the glass substrate 21 and the transparent electrode 24 instead of the lower surface of the transparent electrode 24.

  The phase difference film 14 is used as an optical anisotropic body for color compensation, and corrects the coloring generated in the STN cell 20 to enable black and white display.

  The reflective polarizing plate 40 in the present embodiment uses the reflective polarizing plate 180 described with reference to FIG. 1, and the direction of the transmission axis of the reflective polarizing plate 40 and the direction of the transmission axis of the lower polarizing plate 15 are It almost matches.

  Further, the red 27R, the green 27G, and the blue 27B of the color filter 27 according to the present embodiment are set so that the chromaticity satisfies the formula (1).

  Next, the operation of the display device 10 according to the present embodiment will be described.

  First, in the voltage non-application region of the STN cell 20 in the reflective display, the light incident from the outside becomes light having a linearly polarized component in a predetermined direction by the upper polarizing plate 12, and then the polarization direction is changed by the STN cell 20 at a predetermined angle ( For example, the light has a twisted linearly polarized light component, passes through the light diffusing plate 30, the lower polarizing plate 15, and the reflective polarizing plate 40, and further passes through the light guide 72 and is reflected by the light reflecting plate 60. Is done. The reflected light again passes through the light guide 72, the reflective polarizing plate 40, the lower polarizing plate 15, and the light diffusing plate 30, and the light having the linearly polarized light component whose polarization direction is twisted by a predetermined angle by the STN cell 20. The light is emitted from the upper polarizing plate 12.

  Moreover, even if the polarization direction of the light reflected by the light reflecting plate 60 is changed, the light is repeatedly reflected between the reflecting polarizing plate 40 and the light reflecting plate 60, and eventually from the reflecting polarizing plate 40 to the STN cell 20. Since the light is emitted toward, bright display can be obtained. At this time, if the reflected light passes through the color filter 27, the light can be colored in any of red, green, and blue.

  In the voltage application region of the STN cell 20, light incident from the outside becomes light having a linearly polarized component in a predetermined direction by the upper polarizing plate 12, and then passes through the STN cell 20 as light having this linearly polarized component. It is absorbed by the lower polarizing plate 15 and darkens.

  Next, in the non-voltage application region of the STN cell 20 in the transmissive display, the light emitted from the light source 70 is transmitted as light having a linearly polarized component in a predetermined direction by the reflective polarizing plate 40 and is polarized by the STN cell 20. Light having a linearly polarized light component whose direction is twisted by a predetermined angle is emitted through the upper polarizing plate 12. At this time, the emitted light is colored in the color of the color filter 27 that passes therethrough.

  On the other hand, in the voltage application region of the STN cell 20, light emitted from the light source 70 is transmitted as light having a linearly polarized component in a predetermined direction by the reflective polarizing plate 40, and light having this linearly polarized component is transmitted through the STN cell 20. And passes through the upper polarizing plate 12 and becomes dark.

  As described above, in the display device 10 according to the present embodiment, bright color display can be realized by the color filter 27 composed of three colors of red, green, and blue in both the reflective display and the transmissive display.

  Furthermore, in the display device 10 according to the present embodiment, the chromaticities of red 27R, green 27G, and blue 27B constituting the color filter 27 are set so as to satisfy the formula (1).

  Thereby, the light reflected by the light reflecting plate 60 is not affected by the light diffusing plate 30, the lower polarizing plate 15, the reflective polarizing plate 40, the light source 70, etc., and the white light mixed with red, green, and blue can do. Since the reflected light incident on the STN cell 20 is white, the light emitted from the display device 10 is colored only by the color of the color filter 27 that passes therethrough.

  As a result, white light is emitted from the back side of the STN cell 20 (liquid crystal panel) during reflective display to prevent color display in a mixed color and achieve a clear and bright color display. can do.

<Second Embodiment>
FIG. 6 is a schematic view of a display device according to the second embodiment. In this embodiment, the display device 10 according to the first embodiment is configured as a reflective display device by omitting the light source 70. Even with such a configuration, color display in the reflective display can be performed clearly.

<Third Embodiment>
FIG. 7 is a schematic view of a display device according to the third embodiment. In this embodiment, in the display device 10 according to the first embodiment, the positions of the lower polarizing plate 15 and the light diffusing plate 30 are changed, and the lower polarizing plate 15 and the light diffusing plate 30 are placed below the STN cell 20. They are arranged in order.

<Fourth Embodiment>
FIG. 8 is a schematic view of a display device according to the fourth embodiment. In this embodiment, in the display device 10 according to the third embodiment, the reflective polarizing plate 40 is disposed between the lower polarizing plate 15 and the light diffusing plate 30, and the lower polarizing plate 15 is disposed below the STN cell 20. The reflective polarizing plate 40 and the light diffusing plate 30 are sequentially arranged.

<Fifth Embodiment>
FIG. 9 is a schematic view of a display device according to the fifth embodiment. In this embodiment, the lower polarizing plate 15 is omitted from the display device according to the fourth embodiment. Thus, in the display device according to the present embodiment, the display can be brightened by reducing the number of members through which light passes.

<Sixth Embodiment>
FIG. 10 is a schematic view of a display device according to the sixth embodiment. In this embodiment, in the display device according to the second embodiment, the lower polarizing plate 15, the light diffusing plate 30, the reflective polarizing plate 40 and the light reflecting plate 60 are arranged in this order on the lower side of the STN cell 20.

<Seventh embodiment>
In the second and sixth embodiments, the reflective display device is shown, but the lower polarizing plate 185 may be omitted.

2. Modifications In each of the above-described embodiments, the STN cell 20 is described as an example of the liquid crystal panel. However, the present invention is not limited to this, and the transmission polarization axis is set to the voltage in addition to the TN liquid crystal panel and the ECB liquid crystal panel. Any change may be made.

  The above-described display device 10 includes a personal computer, a pager, a liquid crystal television, a viewfinder type, a monitor direct-view type video tape recorder, a car navigation device, an electronic notebook, a calculator, a word processor, a workstation, a mobile phone, a video phone, The present invention can be applied to an electronic device of a device provided with a POS terminal and a touch panel.

  As described above, in the display device according to the present invention, the distances Rr, Rg, Rb between the white point (0.310, 0.316) and the colors R, G, B are 1. Since 6 <Rr / Rg <3.8 and 1.6 <Rb / Rg <3.8, the light reflected by the light reflecting means and incident on the transmission polarization axis variable means is set. White light can be obtained, and a clear color display can be realized.

It is a perspective view which shows the reflective polarizing plate used for the display apparatus by this invention. It is explanatory drawing which shows the principle of the reflection type display by this invention. It is explanatory drawing which shows the principle of the transmissive display by this invention. It is explanatory drawing which shows the parallax measurement experiment. 1 is a schematic configuration diagram illustrating a display device according to a first embodiment. It is a schematic block diagram which shows the display apparatus by 2nd Embodiment. It is a schematic block diagram which shows the display apparatus by 3rd Embodiment. It is a schematic block diagram which shows the display apparatus by 4th Embodiment. It is a schematic block diagram which shows the display apparatus by 5th Embodiment. It is a schematic block diagram which shows the display apparatus by 6th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Display apparatus 12, 130 ... Upper polarizing plate 15, 160 ... Lower polarizing plate 20 ... STN cell 26 ... Liquid crystal 27, 150 ... Color filter 30, 170 ... Light diffusing plate 40, 200 ... reflective polarizing plate 70 ... light source 80 ... light reflecting plate 140 ... TN liquid crystal panel 190 ... backlight

Claims (3)

Red color system, a liquid crystal panel greenish and color filter having a colored region of blue is provided,
An illuminating device provided on the back side of the liquid crystal panel, and having a light-transmitting light guide and a light source capable of introducing light into the light guide ;
A light reflecting plate that is provided on the opposite side of the lighting device from the liquid crystal panel and reflects outside light;
A polarizing plate provided on the opposite side of the liquid crystal panel from the light reflecting plate;
Comprising
A transmissive display by light from the illumination device and a reflective display by the external light reflected from the light reflector are possible.
The white point is (0.310, 0.316), and the chromaticities of the red, green, and blue colored regions are R (xr, yr), G (xg, yg), and B (x b , y b ), and when the distance between the white point and R, the distance between the white point and G, and the distance between the white point and B are Rr, Rg and Rb, respectively, it passes through the light guide. 1.6 <Rr / Rg <3.8 and 1.6 <Rb / Rg <3.8 are satisfied so as to prevent light emitted from the polarizing plate from being colored. A transflective display device. The display device according to claim 1, further comprising a light diffusing plate having forward scattering characteristics, wherein the outside light that has passed through the color filter is diffused by the light diffusing plate.   An electronic apparatus comprising the display device according to claim 1.

Images