JP2004061747A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device having luminance and precision suitable for various locations where the device is to be used. <P>SOLUTION: The display device is provided with: a display panel having a liquid crystal 16 and reflection pixel electrodes 24; and a plurality of light sources 40 for the display panel irradiation having mutually different emission wavelengths. A space-division type reflective mode and a time-division type transmissive mode can be switched in this display device. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a display device, and more particularly to a display device driven by a field sequential color.
[0002]
[Prior art]
An example of the display device is, for example, a liquid crystal display device. A conventional general color liquid crystal display device is configured as a space division type liquid crystal display device having red, green, and blue color filters. Also, a time-division type color liquid crystal display device called a field sequential color has been developed.
[0003]
In the space division type liquid crystal display device, one pixel includes three color portions of red, green, and blue, and red, green, and blue color filters and corresponding pixel electrodes are arranged in the respective color portions. Display is performed while controlling the red, green, and blue pixel electrodes. A liquid crystal display device including a color filter can easily realize a relatively excellent display, and is therefore widely used at present. However, the liquid crystal display device of the space division type has a problem that it is difficult to further enhance color reproducibility in addition to definition and luminance.
[0004]
In a time-division type liquid crystal display device, one pixel is formed as a single region, and a single region is sequentially irradiated with red, green, and blue light, and color display is performed while controlling pixel electrodes. For example, in a time-division type liquid crystal display device, one frame is divided into three fields, a first field emits red light, a second field emits green light, and a last field emits blue light. Is irradiated.
[0005]
Japanese Patent Laying-Open No. 2000-227782 discloses a time-division type projection type liquid crystal display device. In this publication, a white light source and a rotating color plate are used to sequentially emit red, green, and blue light while rotating the rotating color plate. However, a structure using a white light source and a rotating color plate cannot be used in a liquid crystal display device requiring a compact configuration.
[0006]
Therefore, it is conceivable to use red, green, and blue light sources (for example, red, green, and blue LEDs), sequentially turn on the red, green, and blue light sources, and perform color display while controlling the pixel electrodes. ing. If red, green, and blue light sources are used, a compact liquid crystal display device can be configured.
[0007]
In a time-division type liquid crystal display device, it is not necessary to spatially arrange color filters, so that high definition can be easily achieved. Further, since the color purity of the light of the LED is much better than the color purity of the color filter, the time-division type liquid crystal display device has very excellent color reproducibility.
[0008]
Further, there is a proposal in which a transparent electrode and a reflective electrode are arranged in one pixel, and the liquid crystal display device is switched between a transmissive liquid crystal display device and a reflective liquid crystal display device (for example, JP-A-11-109417, JP-A-2000-2000). -111902, JP-A-2000-29012). However, it is difficult to provide a transparent electrode and a reflective electrode on one substrate.
[0009]
[Problems to be solved by the invention]
Liquid crystal display devices are used in various applications such as PDAs, car navigation systems, mobile phones, and portable notebook PCs. A liquid crystal display device for mobile use is sometimes used indoors, and sometimes used outdoors. The time-division type liquid crystal display device is excellent in color purity and color reproducibility as described above, but when used outdoors, visibility is reduced or color reproducibility is reduced due to lack of luminance. There was a problem.
[0010]
Further, in the time-division type liquid crystal display device, there is a problem that the shorter the lighting time of the LED used as the light source, the lower the light emission intensity. For example, when the time of one frame is 16.7 ms and the time of one field is 5.6 ms, the light emission intensity when the LED is made to emit light for 5.6 ms is that the LED emits light for 16.7 ms. About half of the emission intensity when The actual light emission time of the LED is shorter than the time of one field, and the light emission intensity of the LED further decreases. Therefore, there is a need for a time-division type liquid crystal display device capable of increasing the light emission intensity of the LED.
[0011]
SUMMARY OF THE INVENTION An object of the present invention is to provide a display device having luminance and definition suitable for various use positions.
[0012]
[Means for Solving the Problems]
A display device according to the present invention includes a display panel having an optical shutter, and a plurality of light sources having different emission wavelengths for irradiating the display panel, and is capable of switching between a space division type reflection mode and a time division type transmission mode. It is characterized in that it is configured to be able to perform.
[0013]
According to this configuration, when performing display in the space division type reflection mode, it is possible to bring out the characteristics of the display in the reflection mode particularly when used outdoors, and to perform display in the time division type transmission mode. Therefore, when used indoors, excellent color reproducibility by field sequential color can be obtained.
[0014]
Further, a display device according to the present invention includes a display panel having an optical shutter, and a plurality of light sources having different emission wavelengths for irradiating the display panel, wherein the display panel includes a reflecting member for reflecting light emitted from the light source. The display may be configured such that light sequentially emitted from the plurality of light sources is reflected by the reflection member to perform display.
[0015]
According to this configuration, it is possible to realize display in a time-division type reflection mode.
[0016]
Further, the display device according to the present invention includes a display panel having an optical shutter, and a plurality of light sources having different emission wavelengths for irradiating the display panel, and simultaneously turns on at least two of the plurality of light sources; Light of different colors is sequentially emitted while changing the light source to be turned on.
[0017]
According to this configuration, since one color of light is composed of a plurality of colors of light simultaneously emitted from at least two light sources, the emission intensity can be increased.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0019]
FIG. 1 is a sectional view showing a liquid crystal display device as a display device according to a first embodiment of the present invention, and FIG. 2 is a plan view showing a second substrate of the liquid crystal display device of FIG. The liquid crystal display device 10 includes a liquid crystal display panel including first and second opposed transparent glass substrates 12 and 14 and a liquid crystal 16 inserted between the first and second substrates 12 and 14. The first substrate 12 is a color filter substrate, and has red, green, and blue color filters 18 (18R, 18G, 18B), a black matrix 20, and a transparent ITO common electrode 22.
[0020]
The second substrate 14 is a TFT substrate and includes a pixel electrode 24, a gate bus line 26, a data bus line 28, a TFT 30, and a storage capacitor electrode 32. The pixel electrode 24 is a reflective electrode made of aluminum. The size of the pixel electrode 24 is substantially the same as the size of the color filter 18, and the pixel electrode 24 and the color filter 18 are formed at positions overlapping each other. Thus, one pixel has three color portions, and each color portion includes the color filter 18 and the reflection member 24.
[0021]
FIG. 2 shows the black matrix 20 of the first substrate 12 by a broken line.
The black matrix 20 covers the gate bus line 26, the data bus line 28, and the TFT 30, and has an opening 20A that exposes the color filter 18 and the pixel electrode 24. The area of the opening 20A of the black matrix 20 is larger than the area of the color filter 18 and the pixel electrode 24. For example, the width of the opening 20A of the black matrix 20 is 52 μm, and the width of the pixel electrode 24 is 43 μm. Therefore, the transmission region 34 is formed around the pixel electrode 24. The area including the pixel electrode 24 is a reflection area. Note that an alignment film is provided on the first and second substrates 12 and 14 as needed.
[0022]
Further, as shown in FIG. 1, a polarizing plate 36 is provided outside the first substrate 12, and a polarizing plate 38 is provided outside the second substrate 14. Further, a backlight 40 is provided outside the polarizing plate 38. The backlight 40 includes a light guide plate 40A, an LED array 40B arranged on a side edge of the light guide plate 40A, and a reflector 40C.
[0023]
FIG. 3 is a partial plan view showing the backlight of FIG. The LED array 40B includes a red LED 42R, a green LED 42G, and a blue LED 42B.
These LEDs 42R, 42G, and 42B are a plurality of light sources having different emission wavelengths.
[0024]
In FIG. 1, since the color filter 18 is smaller than the opening 20A of the black matrix 20, a gap is formed between the color filter 18 and the black matrix 20. The common electrode 22 includes a portion covering the color filter 18 and a portion without the color filter 18. The cell thickness of the portion including the color filter 18 (the cell thickness of the reflection region) is larger than the cell thickness of the portion without the color filter 18 (the cell thickness of the transmission region 34).
[0025]
When the liquid crystal display device 10 is used, an electric field 44 is formed between the common electrode 22 and the pixel electrode 24. At the outer edge of the pixel electrode 24, the electric field (line of electric force) 44 </ b> E is formed to bulge outward from the outer edge of the pixel electrode 24. Therefore, although there is no pixel electrode 24 in the transmission region 34, the liquid crystal located in the transmission region 34 is driven by the electric field 44E.
[0026]
In this embodiment, the display in the space division type reflection mode and the display in the time division type transmission mode can be switched and performed.
[0027]
4A and 4B are schematic diagrams illustrating the operation of the liquid crystal display device of FIG. 1, wherein FIG. 4A is a diagram illustrating a space division type reflection mode, and FIG. 4B is a diagram illustrating a time division type transmission mode. FIG. 5 is a flowchart illustrating the operation of the liquid crystal display device 10 of FIG. The liquid crystal 16 and the pixel electrode 24 function as an optical shutter.
[0028]
In FIG. 5, a control device (not shown) provided in the liquid crystal display device 10 determines whether or not the user has selected the reflection mode in step S1. For example, the reflection mode and the transmission mode can be selected by operating buttons (not shown) provided on the liquid crystal display device 10. If the user decides to select the reflection mode, in step S2, all the LEDs 42R, 42G, and 42B of the LED array 40B of the backlight 40 are turned off, and the RGB pixel electrodes 24 are individually controlled. In this case, as shown in FIG. 4A, the external light EL incident on the liquid crystal display device 10 becomes the illumination source. The external light EL passes through the portion of the liquid crystal 16 located on the switched-on pixel electrode 24, is reflected by the pixel electrode 24, passes through the liquid crystal 16 again, and exits from the display surface of the liquid crystal display device 10.
[0029]
Therefore, in this case, the liquid crystal display device 10 functions as a typical reflection type liquid crystal display device including the color filter 18. In an outdoor environment where the external light EL is strong, in the case of a transmission type liquid crystal display device, display light may be obstructed by the external light EL and the display may not be visible. Is a light source, so that a clear display can be obtained. The brighter the outside light EL, the brighter the display and the better the visibility. Thus, the reflection mode is suitable for use outdoors, for example.
[0030]
In step S1, when the user determines that the transmission mode is selected, in step S3, the LEDs 42R, 42G, and 42B of the LED array 40B of the backlight 40 are sequentially turned on, and the pixel electrodes 24 of all the RGB color portions of one pixel are turned on. Control at the same time. In this case, as shown in FIG. 4B, one frame is divided into three fields, the red LED 42R is turned on in the first field, and all the pixels of one pixel are irradiated with the red light RL. The electrodes 24 are controlled simultaneously. The red light RL passes through the portion of the liquid crystal 16 in the transmission region 34 around the pixel electrode 24 that has been switched on, and exits from the display surface of the liquid crystal display device 10. In the next field, the green LED 42G is turned on, and similarly, the green light GL is transmitted. In the last field, the blue LED 42B is turned on, and similarly, the blue light BL is transmitted.
[0031]
In the transmission mode, since the color light of the LEDs 42R, 42G, and 42B is used, all colors can be output with one pixel, and high definition can be achieved. Further, since the color purity of the LED is much better than the color purity of the color filter, the time-division type liquid crystal display device has extremely excellent color reproducibility. However, when the transmission mode is used outdoors, the definition is reduced due to the influence of external light. Therefore, the transmission mode is suitable for indoor use. As a matter of course, the function of measuring the intensity of the external light may be added to the device 10, and the device may automatically switch between transmission and reflection according to the intensity of the external light.
[0032]
FIG. 10 is a chromaticity diagram of the liquid crystal display device. A triangle A represented by black triangle dots indicates a color reproduction range of a reflective liquid crystal display device including a color filter. A triangle B represented by a black dot indicates a color reproduction range of a transmission type liquid crystal display device including a color filter. A triangle C represented by a white circle dot indicates a color reproduction range of a field sequential color driven liquid crystal display device including the LEDs 42R, 42G, and 42B. The color reproduction range of a liquid crystal display device driven by a field sequential color is very wide.
[0033]
In the reflection mode of the space division type, when displaying red, displaying green, and displaying blue, the transmission regions 34 of all the color portions of one pixel are used. Is small, the total area of the transmissive regions 34 is large, and a bright display can be obtained. On the other hand, when used in the reflection mode, the area of the transmission region 34 can be small, so that the area of the reflection region does not need to be largely reduced.
[0034]
If the liquid crystal used is the same, it is desirable that the cell thickness in the case of the transmission type liquid crystal display device is larger than the cell thickness of the reflection type liquid crystal display device in order to adjust Δnd. In this embodiment, since the color filter 18 is not provided in the transmission region 34 outside the pixel electrode 24 as the reflection electrode, the cell thickness of the transmission region 34 can be increased. Therefore, it is possible to set the optimal cell thickness for each of the transmission region 34 and the reflection region. For example, when the cell thickness of the reflection region is 1.0 μm and the film thickness of the color filter 18 is 1.0 μm, the transmission region 34 can secure a cell thickness of 2.0 μm.
[0035]
In the examples, a liquid crystal display panel of homogeneous alignment was prepared using positive type liquid crystal with Δn = 0.2. The aperture ratio of the transmission path 34 around the pixel electrode 24 was about 12%. When used as a liquid crystal display device driven by a field sequential color, the light utilization efficiency was 91% of the light utilization efficiency of a general reflection type liquid crystal display device including a front light and a color filter. The color reproducibility is very excellent, which is unique to a liquid crystal display device driven by a field sequential color. Even when switching to the reflection mode, the area of the pixel electrode 24, which is a reflection electrode, is not reduced, so that extremely high visibility can be secured even when used outdoors.
[0036]
FIG. 6 is a plan view showing a modified example of the liquid crystal display device shown in FIGS. The liquid crystal display device 10 of this example has basically the same configuration as the liquid crystal display device 10 of FIGS. In this example, the pixel electrode 24 has an opening 46 formed as a cutout region or a cutout region, so that the aperture ratio of the transmission region 34 is increased.
The total aperture ratio of the transmission area 34 was set to 30%. In this case, the light use efficiency when used in the reflection mode is small, but this embodiment is effective when it is assumed that the device is used in the transmission mode indoors. A plurality of openings 46 provided in the pixel electrode 24 are provided in a stripe shape with a width of about 10 μm in a direction parallel to the gate bus line 26. An opening is also provided in the color filter 18 according to the shape of the opening 46 of the pixel electrode 24.
[0037]
The light use efficiency of the transmission mode liquid crystal display device of this example is 2.36 times the light use efficiency of the reflection type liquid crystal display device using the front light and the color filter, and the transmission type liquid crystal display device using the backlight and the color filter. The light use efficiency of the liquid crystal display device was reduced by about 30%, and the light use efficiency was considerably high. The transmission mode liquid crystal display device of this example is suitable mainly for indoor use.
[0038]
FIG. 7 is a cross-sectional view showing a modification of the liquid crystal display device shown in FIGS. The liquid crystal display device 10 of this example has basically the same configuration as the liquid crystal display device 10 of FIGS. In the liquid crystal display device shown in FIGS. 1 to 6, the cell thickness is changed between the transmission region 34 and the reflection region to optimize the cell thickness. In this example, the first substrate 12 has a flattening film 48 covering the color filters 18 (18R, 18G, 18B) and the black matrix 20, and the common electrode 22 is formed on the flattening film 48. . In this case, the cell thickness was optimized in the reflection area. As a result, the cell thickness of the transmission region 34 deviates from the optimum value, and the transmittance of the liquid crystal panel decreases. Nevertheless, the light utilization efficiency was within the usable range for some applications.
[0039]
FIG. 8 is a sectional view showing a modification of the liquid crystal display device shown in FIGS. In this example, a reflective liquid crystal display panel having color filters 18 (18R, 18G, 18B) and a front light 40F are used. Like the backlight 40, the front light 40F includes a light guide plate 40A, an LED array 40B arranged on a side edge of the light guide plate 40A, and a reflector 40C. As shown in FIG. 3, the LED array 40B includes a red LED 42R, a green LED 42G, and a blue LED 42B. In the backlight 40, a diffuse reflection layer is provided so that light passing through the light guide plate 40A is emitted upward (toward the liquid crystal display panel), whereas in the front light 40F, light passing through the light guide plate 40A is provided. Is provided on the surface so that the light exits downward (toward the liquid crystal display panel).
[0040]
In this example, the area of the color filter 18 and the area of the pixel electrode 24 are made larger than the area of the opening of the black matrix 20, so that the transmission region 34 of the previous example is eliminated. Therefore, the liquid crystal display device 10 is a reflection type liquid crystal display device driven by a field sequential color. That is, the pixels are sequentially irradiated with red, green, and blue light. The R, G, and B pixel electrodes 24 are controlled in synchronization with the irradiation of red, green, and blue light. Therefore, for example, the red light is irradiated on the red color filter 18, so that the color purity is increased. As a result, the light use efficiency is not much different from the light use efficiency of the reflection type liquid crystal display device driven normally, but the color reproducibility is dramatically increased, so that the use efficiency is high depending on the application.
[0041]
FIG. 9 is a cross-sectional view showing a modification of the liquid crystal display device shown in FIGS. The liquid crystal display device 10 of this example is configured as a reflective liquid crystal display device having pixels in a single area without a color filter. In this example, a front light 40F is used, and field sequential color driving is applied. That is, the pixels are sequentially irradiated with red, green, and blue light, and the pixel electrode 24 is controlled in synchronization with the irradiation of the color light. With this configuration, good color development and high light use efficiency can be obtained in a dark environment. However, when external light enters, reflected light is affected, so that color reproducibility is reduced.
[0042]
FIG. 11 is a schematic diagram showing a liquid crystal display device 50 as a display device according to a second embodiment of the present invention. FIG. 12 is a diagram showing a rubbing direction, a polarization axis, and a phase axis of the liquid crystal display device 50 of FIG. FIG. 13 is a sectional view showing a liquid crystal display panel of the liquid crystal display device of FIG. FIG. 14 is a plan view showing a second substrate of the liquid crystal display panel of FIG.
[0043]
11, the liquid crystal display device 50 includes a liquid crystal display panel 52, a phase difference plate 54, polarizing plates 56 and 58, and a backlight 60. As shown in FIG. 13, the liquid crystal display panel 52 includes first and second opposed transparent glass substrates 62 and 64 and a liquid crystal 66 inserted between the first and second substrates 12 and 14. Consists of The first substrate 12 has a transparent common electrode 68 and an alignment film 70. The second substrate 64 has a transparent pixel electrode 72 and an alignment film 74.
[0044]
As shown in FIG. 14, the second substrate 64 is a TFT substrate, and has a pixel electrode 72, a gate bus line 76, a data bus line 78, a TFT 80, and a storage capacitor electrode 82.
[0045]
12, arrows 83 and 84 indicate the rubbing directions of the alignment films 70 and 74, arrows 85 indicate the directions of the slow axes of the phase difference plates 54, and arrows 86 and 87 indicate the directions of the polarization axes of the polarizing plates 56 and 58. Indicates the direction.
[0046]
The backlight 60 includes a light guide plate 60A, an LED array 60B arranged on a side edge of the light guide plate 60A, and a reflector 60C. The LED array 60B includes a red LED, a green LED, and a blue LED, like the LED array 40B shown in FIG. These LEDs are a plurality of light sources having different emission wavelengths.
[0047]
FIG. 15 is a diagram illustrating an example of control of the light source of the liquid crystal display device of FIG. FIG. 16 is a diagram showing the light emission intensity of the light source of FIG. In this embodiment, field sequential color driving is applied. In this case, one frame (for example, 16.7 ms) is divided into three fields (5.6 ms), and at least two light sources among a plurality of light sources having different emission wavelengths are simultaneously turned on in each field, and the light sources to be turned on are determined. While changing, different colors of light are sequentially emitted.
[0048]
In FIG. 15, the red LED and the green LED are turned on in the first field, and yellow light is emitted. In the second field, the green LED and the blue LED are turned on to emit cyan light. In the third field, the blue LED and the red LED are turned on to emit magenta light. The pixel electrode 24 is controlled according to the irradiation color.
[0049]
In FIG. 16, each LED is lit twice in one frame, and a luminous intensity twice as high as when lit once is obtained, and the brightness is improved. With this configuration, good color development and high light use efficiency can be obtained in a dark environment. That is, when focusing on one light source, for example, red, red forms two colors of magenta and yellow. As described above, since the light emitted from one light source forms two or more colors of a plurality of colors that are sequentially irradiated, the time during which the light source is not turned on (does not contribute to brightness) can be shortened. Thus, the light source can be used effectively.
[0050]
FIG. 17 is a diagram showing a modification of the control of the light source in FIG. Also in this example, at least two of the plurality of light sources having different emission wavelengths are simultaneously turned on in each field, and different colors of light are sequentially emitted while changing the light source to be turned on. Further, in this example, one light emission from one light source forms two or more consecutive colors of the light of a plurality of colors that are sequentially irradiated.
[0051]
The green LED is continuously turned on during the period in which the irradiation colors are yellow and cyan.
The blue LED was lit continuously during the period when the irradiation colors were cyan and magenta. The red LED is lit continuously during the period in which the irradiation colors are magenta and yellow (although it looks like it is split in the figure, it is actually a continual light since the figure is a repetition). Thereby, the lighting time per one light source can be lengthened. Here, the lighting time per light source could be increased from 5.6 ms to 11.2 ms. The duty is improved from 33.3% to 66.7%.
FIG. 19 shows the relationship between the lighting time ratio (duty) and the light emission intensity when the power consumption of the light source is constant. The emission intensity increases as the duty increases. By improving the duty, the brightness can be improved about 1.4 times. Furthermore, the power consumption remains constant. In the case of FIG. 15, although the effect of increasing the luminance is obtained, the number of times of lighting is doubled, so that the power consumption is also doubled. In the example of FIG. 17, since the number of lightings does not increase, the brightness can be improved without increasing the power consumption.
[0052]
FIG. 18 is a diagram showing a modification of the control of the light source in FIG. Also in this example, at least two of the plurality of light sources having different emission wavelengths are simultaneously turned on in each field, and different colors of light are sequentially emitted while changing the light source to be turned on. Further, in this example, the light emission intensity of one light source or the number of lights of a plurality of light sources having substantially equal light emission wavelength characteristics is changed according to the irradiation color. In one example, the emission intensity was set to red: green = green: blue = blue: red = 1: 3.
[0053]
In the examples of FIGS. 15 and 17, although the luminance is high, there is a problem that the color reproducibility is reduced. For example, referring to the chromaticity diagram of FIG. 10, in a conventional field sequential color driving liquid crystal display device, the color reproduction range is represented by a triangle C represented by white circle dots. In the example of FIG. 15, by turning on a plurality of light sources having different emission wavelengths at the same time, the color reproduction range becomes a triangle connecting the midpoints of the sides of the triangle C, that is, a triangle D represented by white square dots. The range decreases.
[0054]
In order to improve this, when the light emission intensity of one light source is changed in accordance with the irradiation color, the triangle of the color reproduction range is a triangle composed of points closer to the vertex than the middle point of each side of the triangle C, that is, , A triangle E represented by white rhombic dots or a triangle F represented by white triangular dots, the brightness improvement effect is slightly reduced, but the color reproduction range is improved. It can be said that by using a light source such as an LED capable of a wide color reproduction range, a plurality of light sources can be simultaneously turned on and the brightness can be improved while ensuring color reproducibility.
[0055]
In addition to the above features, the irradiation color can be switched by an external switch or the like. For example, when priority is given to color purity (luminance is sacrificed), red, green, and blue light are sequentially emitted as in the related art. If you want to give priority to brightness (sacrifice color purity), press the external switch to turn on red and blue at the same time, blue and green at the same time, and green and red at the same time. It is possible to use them appropriately. Either the emission wavelength or the emission intensity of the light source that forms one irradiation color can be switched.
[0056]
In addition, three kinds of LEDs having emission wavelengths of red, blue and green were used as light sources (Nichia Chemical). An example has been described in which three light sources of red, blue, and green are used as the light source, and two of the LEDs are simultaneously lit. However, the light source and the lighting means used in the present invention are not limited to this example.
[0057]
The liquid crystal display panel had 320 × 240 pixels and a 3.5-inch screen size.
Alignment films 70 and 74 were formed on both substrates 62 and 64 using a printing method. As the alignment films 70 and 74, horizontal alignment films manufactured by JSR were used. Furthermore, after bonding both substrates 62 and 64 to the alignment films 70 and 74, rubbing was performed in a direction parallel and in a half body direction (arrows 83 and 84). Next, the two substrates were bonded together via a seal and a spacer to form an empty cell, and liquid crystal was injected by vacuum injection. As the liquid crystal material, a material made of Merck having a Δn of 0.2 and a positive dielectric anisotropy was used. The cell thickness was 2 μm.
[0058]
On one side of the liquid crystal display panel thus manufactured, in order to obtain sufficient black luminance when a high voltage is applied, a retardation film (phase difference plate) 54 having a phase difference of 100 nm is provided with a slow axis 85 perpendicular to the rubbing direction. It was arranged as follows. Further, polarizing plates 56 and 58 were arranged on both sides of the liquid crystal display panel such that the polarizing axes 86 and 87 were perpendicular to each other and were at 45 degrees from the rubbing direction.
[0059]
【The invention's effect】
As described above, according to the present invention, it is possible to obtain a display device having luminance and definition suitable for various use positions.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a liquid crystal display device according to a first embodiment of the present invention.
FIG. 2 is a plan view showing a second substrate of the liquid crystal display device of FIG.
FIG. 3 is a partial plan view showing the backlight of FIG. 1;
4A and 4B are schematic diagrams illustrating the operation of the liquid crystal display device of FIG. 1, wherein FIG. 4A is a diagram illustrating a space-division type reflection mode, and FIG. 4B is a diagram illustrating a time-division type transmission mode. .
FIG. 5 is a flowchart illustrating an operation of the liquid crystal display device of FIG. 1;
FIG. 6 is a plan view showing a modification of the liquid crystal display device shown in FIGS. 1 and 2.
FIG. 7 is a sectional view showing a modification of the liquid crystal display device shown in FIGS. 1 and 2;
FIG. 8 is a sectional view showing a modification of the liquid crystal display device shown in FIGS. 1 and 2.
FIG. 9 is a sectional view showing a modification of the liquid crystal display device shown in FIGS. 1 and 2;
FIG. 10 is a chromaticity diagram of the liquid crystal display device.
FIG. 11 is a view showing a liquid crystal display device according to a second embodiment of the present invention.
12 is a diagram illustrating a rubbing direction, a polarization axis, and a phase axis of the liquid crystal display device of FIG.
13 is a sectional view showing a liquid crystal display panel of the liquid crystal display device of FIG.
FIG. 14 is a plan view showing a second substrate of the liquid crystal display panel of FIG.
15 is a diagram illustrating an example of control of lighting of a light source of the liquid crystal display device of FIG. 11;
16 is a diagram showing the light emission intensity of the light source of FIG.
FIG. 17 is a diagram showing a modification of the lighting control of the light source in FIG. 15;
18 is a diagram showing a modification of the lighting control of the light source in FIG.
FIG. 19 is a diagram showing the relationship between the duty and emission intensity of an LED.
[Explanation of symbols]
12,14 ... substrate
16 ... Liquid crystal
18 ... Color filter
20 ... Black matrix
24 ... pixel electrode
34 ... Transmissive area
40 ... Backlight
42… LED
60 ... Backlight
72 ... pixel electrode

Claims (6)

A display panel having an optical shutter, and a plurality of light sources having different emission wavelengths for irradiating the display panel, and configured to be switchable between a space division type reflection mode and a time division type transmission mode. A display device, comprising: The display panel includes a liquid crystal display panel including a liquid crystal inserted between a pair of substrates and electrodes for applying an electric field to the liquid crystal, wherein one pixel includes three color portions, and each color portion includes a color filter. The display device according to claim 1, further comprising a reflection electrode. One substrate has a black matrix having an opening, the area of the color filter is substantially equal to the area of the reflective electrode, the area of the color filter and the area of the reflective electrode are smaller than the area of the opening of the black matrix, The display device according to claim 2, wherein a region outside the reflective electrode is a region through which light is transmitted in the transmission mode. A display panel having an optical shutter, and a plurality of light sources having different emission wavelengths for irradiating the display panel, the display panel includes a reflecting member for reflecting light emitted from the light source, and sequentially from the plurality of light sources A display device characterized in that irradiated light is reflected by the reflection member to perform display. A display panel having an optical shutter; and a plurality of light sources having different emission wavelengths for irradiating the display panel. A display device characterized in that light of colors is sequentially emitted. The display device according to claim 5, wherein the light emitted from one light source forms at least two colors of light of different colors sequentially emitted.

Images