WO2003001495A1 - Liquid crystal display and electronic device - Google Patents

Abstract

A liquid crystal display (1) having a liquid crystal (14) of an OCB mode, wherein image signals for three colors composed of two colors selected from red, green, and blue and of white according to an image signal inputted from an external device, an image is displayed during the sub−frame period during which a backlight (20) emits the lights of the three colors according to an image signal relating to the sub−frame period, black is displayed during the sub−frame period during which the backlight (20) emits the light of the nonselected color out of the three colors, thus displaying the image by the field−sequential color display method.

Description

 Details

Liquid crystal display and electronic equipment

〔Technical field〕

 The present invention relates to a liquid crystal display device that displays an image, and more particularly to a field sequential color liquid crystal display device having an OCB (Optically Self Compensated Birefringence) mode liquid crystal and an electronic apparatus including the liquid crystal display device.

 (Technical background.)

 A method for realizing a color display by a liquid crystal display device is that white light emitted from a light source passes through the color filters of three primary colors (red, green, and blue) provided for each pixel. The color-filled evening system, which provides a blank display, is the most popular. In the case of such a color filter system, when light emitted from a light source passes through a color filter, only light of a specific wavelength is selected and transmitted, and light of other wavelengths is absorbed. Therefore, there was a problem that the light use efficiency was low and the power loss was large. For this reason, a field-sequential color method has been proposed in which a plurality of light sources each emitting different color light are turned on in a time-division manner to perform color display. In the case of such a field sequential color system, light emitted from each color light source is used for image display without passing through a color filter. Therefore, high light use efficiency can be obtained, and power saving can be achieved. In addition, since color filters are not required, costs can be reduced.

Fig. 1 shows a conventional field-sequential color liquid crystal display device. (A) is a diagram showing light emission intensity and light emission time of each light source of red, green, and blue, and (b) is a timing chart showing a change in light transmittance of a liquid crystal display panel. FIG.

 As shown in Fig. 1 (a), one frame period of an image signal is composed of three sub-frame periods, and a red (R), green (G), and blue (B) light source is used for each sub-frame period. Each color light is emitted by sequentially emitting light at a predetermined emission intensity.

 Also, as shown in FIG. 1 (b), the light transmittance of the liquid crystal display panel is changed according to the image signal. Since the light transmittance of the liquid crystal display panel changes as described above, the color intensity of each color in the liquid crystal display panel is adjusted, and an image corresponding to the image signal is displayed.

 Generally, color display in a display device is realized by combining three colors of a color triangle on a chromaticity coordinate as shown in FIG. Therefore, as described above, it is possible to display an arbitrary color by changing the light transmittance of the liquid crystal display panel and adjusting the color intensities of the three colors red, green, and blue.

 In such a field sequential liquid crystal display device, one frame period of an image signal is composed of a plurality of subframe periods, and the liquid crystal completes a response in each of the subframe periods. There is a need. Therefore, if the response of the liquid crystal is slow, good image display cannot be realized. Therefore, it is desirable to use an OCB mode liquid crystal capable of high-speed response.

In a liquid crystal display device equipped with an OCB mode liquid crystal, a relatively high voltage is applied between a pixel electrode and a counter electrode to change the liquid crystal alignment state from a so-called splay alignment to a bend alignment. It is characterized by displaying an image depending on the state. The liquid crystal display device having such an OCB mode liquid crystal is described in “The Institute of Telecommunications Society of Japan, Academic report, EDI98-144, p.199 ”.

 In the case of the above-described liquid crystal display device of the field sequential color system, there is a problem that color breakage occurs when displaying a moving image. Here, color division refers to a phenomenon in which the outline of an image pattern is colored when a moving image is displayed. Such color breakup is due to the time-divisional color display as shown in FIG. Hereinafter, the occurrence of color breakup will be described more specifically.

 When white is displayed in a certain pixel, colors are displayed in the order of RGB in each subframe period. Similarly, when black is displayed, the transmittance of light is reduced, and none of the RGB colors is displayed. In the following, for example, the case where white display is performed over three frame periods is expressed as “RG B / RGB / RGB”, and the case where black display is performed over three frame periods is “nnn Z nnn / nnn ". Note that "/" indicates a frame period break.

 Here, it is assumed that a white image pattern moves in a predetermined direction, so that a certain pixel displays white for three frame periods and displays black for the next three frame periods. Suppose. In this case, according to the above description, “RGBZRGBZRGB / nnnZnnnZnnn” is obtained. However, there are cases where the observer cannot recognize the end of the frame period. In particular, such a situation may occur depending on the timing of blinking of the observer. If the observer is unable to recognize the frame period break, the observer may perceive it as "RGZBRG ZB RG / B n nZn n nZn nn / n", for example. is there. That is, it may be perceived that blue is displayed after white display is completed, and then black display is started thereafter. As a result, a color break that causes coloring in the contour of the image pattern is perceived by the observer.

DMD (Digital Micromirror Device) Japanese Patent Application Laid-Open No. 7-30999 discloses an example in which a color breakup can be reduced by high-frequency driving in the case of a display device of a char-color system. However, liquid crystal has a slow response compared to DMD, and such high frequency driving is extremely difficult.

 Also, 液晶 In a liquid crystal display device equipped with CB mode liquid crystal, when a voltage close to 0 V is repeatedly applied between the pixel electrode and the counter electrode, the alignment state of the liquid crystal reversely transitions from bend alignment to splay alignment. Sometimes. When such reverse transition occurs, images cannot be displayed normally. Therefore, it is necessary to take measures to prevent reverse transition in order to stably display good images.

 The present inventors have proposed that when displaying a desired color by displaying red, green, and blue, which are far apart on the chromaticity coordinates in a time-division manner, the color expression range is widened, but the degree of color breakup Was found to be large. Then, it was found that it is possible to reduce color breakup by displaying a plurality of colors at close positions on the chromaticity coordinates in a time-division manner.

 In addition, it was found that reverse transition can be prevented by performing black display in a subframe period related to a color that is not used for display among red, green, and blue.

 The present invention has been made based on such knowledge, and an object of the present invention is to provide a liquid crystal display device capable of reducing color cracking and preventing reverse transition.

 [Disclosure of the Invention]

In order to achieve this object, a liquid crystal display device according to the present invention includes a first substrate having a plurality of pixel electrodes arranged in a matrix, a second substrate facing the first substrate, A liquid crystal layer made of liquid crystal sandwiched between the first substrate and the second substrate; a counter electrode provided on the first substrate or the second substrate; and at least three colors of light. Light source An illumination device that irradiates light of a plurality of colors toward the liquid crystal layer; and driving the liquid crystal by generating a potential difference between each of the pixel electrodes and the counter electrode. Driving means for adjusting the transmittance of the illuminated light in the liquid crystal layer; and illuminating device controlling means for controlling the illuminating device so as to sequentially emit the light of each of the plurality of colors in one frame period, The alignment state in the display state of the liquid crystal is different from the alignment state in the non-display state of the liquid crystal, and in the alignment state in the display state, a predetermined voltage is applied between the pixel electrode and the counter electrode. It is necessary that the orientation state of the display state is maintained, and the one frame period includes four or more sub-frame periods, and the plurality of colors are provided in each of the sub-frame periods. The lighting device control means is controlled so that the one color light is emitted by the lighting device, and three colors are selected from the plurality of colors based on an image signal corresponding to an image to be displayed, and the selected one is selected. In a sub-frame period in which the illumination device irradiates light of three colors, a voltage corresponding to an image signal related to the sub-frame period is applied between each of the pixel electrodes and the counter electrode, and the selected 3 In a sub-frame period in which the illumination device irradiates light of a color other than the color, a voltage corresponding to a black display signal is applied between each of the pixel electrodes and the counter electrode to drive the liquid crystal and to output the image signal. And a voltage corresponding to the black display signal is equal to the predetermined voltage.

 Further, in the liquid crystal display device according to the present invention, the lighting device has a light source that emits red, green, and blue light, respectively, and the plurality of colors are four colors of red, green, blue, and white. Is preferred.

Further, in the liquid crystal display device according to the present invention, the length of a sub-frame period in which a voltage corresponding to the black display signal is applied between each of the pixel electrodes and the counter electrode is 10% of one frame period. It is preferable that this is the case. Further, in the liquid crystal display device according to the invention, it is preferable that the light source is a light emitting diode.

 Further, in the liquid crystal display device according to the invention, the liquid crystal is normally

It is preferable that the liquid crystal is an OCB mode liquid crystal in a white mode, the liquid crystal is in a bend alignment state in a display state, and the liquid crystal is in a splay alignment state in a non-display state.

 Further, the electronic device according to the present invention includes the liquid crystal display device according to the present invention, and is configured to output an image signal to the liquid crystal display device.

 The above objects, other objects, features, and advantages of the present invention will be apparent from the following detailed description of preferred embodiments with reference to the accompanying drawings.

 [Brief description of drawings]

 FIG. 1 is a timing chart showing the operation of a conventional field-sequential color liquid crystal display device, in which (a) shows the light emission intensity and light emission time of the red, green, and blue light sources. FIG. 3B is a diagram showing a change in light transmittance of the liquid crystal display panel.

 FIG. 2 is a diagram illustrating a color triangle on chromaticity coordinates.

 FIG. 3 is a perspective view showing a configuration of the liquid crystal display device of the present invention according to Embodiment 1.

 FIG. 4 is a cross-sectional view schematically showing the alignment state of the liquid crystal.

 FIG. 5 is a block diagram showing a configuration of the liquid crystal display device of the present invention according to Embodiment 1.

 FIG. 6 is a diagram illustrating a color triangle on chromaticity coordinates.

FIG. 7 is an evening timing chart showing the operation of the liquid crystal display device according to the first embodiment of the present invention, in which (a) shows the emission intensity and emission time of the red, green, and blue light emitting diodes. (B) is a diagram showing the transition of the light transmittance of the liquid crystal display panel. FIG. 8 is a diagram showing the appearance of an electronic device provided with the liquid crystal display device of the present invention according to Embodiment 1, wherein (a) shows the appearance of a digital video camera, and (b) shows the appearance. It is a figure showing the appearance of a portable terminal unit.

 [Best mode for carrying out the invention]

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

 (Embodiment 1)

 FIG. 3 is a perspective view showing a configuration of the liquid crystal display device of the present invention according to Embodiment 1. As shown in FIG. 3, the liquid crystal display device 1 according to the first embodiment includes a liquid crystal display panel 10. The liquid crystal display panel 10 includes two substrates, that is, an upper substrate 11 and a lower substrate 12 as shown in FIG. The upper substrate 11 and the lower substrate 12 are arranged to face each other via a spacer (not shown). Further, a liquid crystal layer 13 is formed by injecting a liquid crystal 14 into a gap formed between the upper substrate 11 and the lower substrate 12.

 The upper substrate 11 is formed by laminating a counter electrode 6 and an alignment film 4 on the lower surface of a glass substrate 2 and a phase difference compensator 7 and a polarizing plate 8 on the upper surface. Further, the lower substrate 12 is configured such that a pixel electrode 40 and an alignment film 5 described later are laminated on the upper surface of the glass substrate 3 and a polarizing plate 9 is laminated on the lower surface similarly.

 Needless to say, a phase difference compensating plate may be provided on the lower substrate 12 side as necessary. Further, as described above, the configuration may be such that the counter electrode 6 is not formed on the upper substrate 11 side, but is formed on the lower substrate 12 side. Therefore, for example, the configuration may be the same as that of a liquid crystal display device of an IPS (In-Plane-Switch) mode.

The liquid crystal display panel 10 thus configured is provided on the upper substrate 11. When a predetermined voltage is applied between the counter electrode 6 and the pixel electrode 40 provided on the lower substrate 12, the alignment state of the liquid crystal 14 is changed from the splay alignment (FIG. 4 (a)) to the bend alignment (FIG. 4 (a)). 4Transfer to Fig. (B)) and display an image according to this bend orientation state. That is, the liquid crystal display panel 10 is a liquid crystal display panel provided with a so-called OC B. mode liquid crystal. In the case of the field sequential color system, one frame period of an image signal is composed of a plurality of subframe periods, and it is necessary for the liquid crystal to complete a response in each subframe period. Therefore, if the response of the liquid crystal is slow, good image display cannot be realized. Therefore, it is desirable that the liquid crystal display panel included in the liquid crystal display device of the present invention be a liquid crystal display panel including an OCB mode liquid crystal capable of high-speed response of the liquid crystal.

 The liquid crystal display panel 10 has a relatively low voltage (about 1.5 V or more and about 2 V or less) between the counter electrode 6 provided on the upper substrate 11 and the pixel electrode 40 provided on the lower substrate 12. ) Is displayed when white is applied, and black when relatively high voltage (approximately 4.5 V or more and 6.5 V or less) is applied. That is, the liquid crystal display panel 10 is a so-called normally-mode liquid crystal display panel.

A backlight 20 as an illumination device is arranged below the liquid crystal display panel 10 described above. The backlight 20 includes a light guide plate 21 made of a transparent rectangular synthetic resin plate, and a light source 23 (a light source plate 23) disposed near the one end surface 22 of the light guide plate 21 and facing the end surface 22. 23 R, 23 G, and 23 B). The light sources 23 R, 23 G, and 23 B are light emitting diodes (LEDs) that emit red, green, and blue light, respectively. Light emitting diodes are characterized by excellent responsiveness (rapid rise and fall of light emission) and little afterglow. Therefore, it is a light source suitable for field sequential driving as described later. However, the light source provided in the liquid crystal display device of the present embodiment is not limited to the light emitting diode. For example, it may be a cold cathode tube, an electroluminescent light emitting element, or the like. Further, in the present embodiment, the description has been given by taking as an example an edge-light type backlight in which the light source is disposed near one end face 22 of the light guide plate 21, but the light source is disposed below the light guide plate 22. A direct-type backlight in which a light source is arranged may be used.

 In the backlight 20 configured as described above, light emitted from the light emitting diodes 23 R, 23 G, and 23 B of the respective colors enters the light guide plate 21 from the end face 22. The incident light is scattered inside the light guide plate 21 and emitted from the upper surface. As a result, the entire liquid crystal display panel .10 is irradiated with red, green, or blue light.

 FIG. 5 is a block diagram showing a configuration of the liquid crystal display device 1 according to the first embodiment of the present invention. Referring also to FIGS. 3 and 4, the liquid crystal display panel 10 is a well-known TFT (Thin Film Transistor) type liquid crystal display element, and has an upper substrate (a counter electrode 6 formed on an inner surface thereof). The counter substrate) 11 and the lower substrate (array substrate) 12 on which the pixel electrode 40, the gate line 31, the source line 32 and the switching element 33 are formed on the inner surface are the liquid crystal layer. They are arranged so as to oppose each other with 13 interposed therebetween. Further, in the array substrate 12, the gate lines 31 and the source lines 32 are arranged so as to intersect alternately, and the pixels are partitioned by the gate lines 31 and the source lines 32. Correspondingly, a pixel electrode 40 and a switching element 33 are formed. A gate line 31 and a source line 32 are driven by a gate driver 34 and a source driver 35, respectively.

 The operation of the knock light 20 is controlled by the backlight control circuit 37.

In the liquid crystal display device 1 configured as described above, the control circuit 36 controls the light-emitting diodes 23 R, 23 G, and 23 B to emit light corresponding to the sub-frame period. The control signal is output to 7. Further, the control circuit 36 displays an image related to each color in synchronization with the light emission of the light emitting diodes 23 R, 23 G, and 23 B based on an image signal input from an external device. An image signal to be output to the source driver 35 is generated as described later. Then, the control circuit 36 outputs the image signal thus generated, and outputs a control signal to the gate driver 34 and the source driver 35. As a result, the gate driver 34 outputs a scanning signal corresponding to a voltage for turning on the switching element 33 to the gate line 31 so as to sequentially turn on the switching element 33 of each pixel. On the other hand, the source driver 35 sequentially writes the image signal to the pixel electrode 40 of each pixel via the source line 32 at the timing.

 More specifically, the gate driver 34 outputs the above-described scanning signal to the gate line 31 of the first row, so that the switching element 33 connected to the gate line 31 of the first row is output. Turn on. When the switching element 33 is turned on, the image signal output from the source driver 35 to each source line 32 is written to the pixel electrode 40 of the pixel in the first row.

 Next, the gate driver 34 outputs a signal corresponding to a voltage for turning off the switching element 33 to the gate line 31 in the first row, and the gate line 31 in the first row. The switching element 33 connected to the second row is turned off, and the gate driver 34 simultaneously outputs the scanning signal to the gate line 31 in the second row, thereby setting the gate in the second row. Turn on the switching element 33 connected to the line 31. Then, similarly to the case of the first row, the image signal output from the source driver 35 to each source line 32 is written to the pixel electrode 40 of the pixel of the second row.

By performing the same operation thereafter, the image signal is sequentially written to the pixel electrodes 40 of the pixels in each row. As a result, the counter electrode 6 and the pixel electrode 40 The liquid crystal 14 is driven by the occurrence of a potential difference between them, and the transmittance of light emitted from the backlight 20 in the liquid crystal display panel 10 changes. As a result, an image corresponding to the image signal appears in the eyes of the observer.

 Next, the image signal generation processing executed by the control circuit 36 will be specifically described. In the liquid crystal display device 1 of the present invention, points on the chromaticity coordinates are represented by two colors of red, green, and blue and three colors of white (see FIG. 6). Therefore, the control circuit 36 determines the two colors of red, green, and blue and the three colors of white based on an image signal composed of information on the three colors of red, green, and blue input from an external device. An image signal composed of information related to color is generated. Note that the control circuit 36 includes an image memory for storing an image signal input from an external device in order to execute the following processing.

 For example, when an image is displayed in accordance with an image signal input from an external device, pixels where red, green, and blue are displayed with color intensities of 100%, 50%, and 30%, respectively, are displayed. Suppose. In this case, the color intensity of blue, which has the lowest color intensity value among red, green, and blue, is changed from 30% to 0%. Then, 30%, which is the blue color intensity before the change, is set as the white color intensity. The red and green color intensities shall be the values obtained by subtracting the blue color intensity before the change from those color intensities. That is, the red color intensity is 70 (= 1100-30)%, and the green color intensity is 20 (= 50-30)%. Therefore, image signals are generated such that the color intensities of red, green, blue, and white are 70%, 20%, 0%, and 30%, respectively. In this case, it is not necessary to display blue in the sub-frame period in which the blue light emitting diode 23B emits light. Therefore, a black display signal is written to the pixel electrode 40 during this sub-frame period.

In the case of the liquid crystal display device 1 of the first embodiment, white display is realized by simultaneously emitting the red, green, and blue light emitting diodes 23 R, 23 G, and 23 B. Thus, a white color intensity of 30% means that the red, green, and blue color intensities are each increased by 30%. So Therefore, if the color intensities of red, green, blue, and white are 70%, 20%, 0%, and 30%, respectively, as described above, the red and green displayed on the LCD panel 10 are , And blue color intensities are 100%, 50%, and 30%, respectively. Therefore, an image is displayed with the same color intensity as when displayed according to an image signal input from an external device.

 FIG. 7 is a timing chart showing the operation of the liquid crystal display device 1 according to the first embodiment of the present invention, in which (a) shows the emission intensity and emission time of the red, green, and blue light emitting diodes. And (b) is a diagram showing the transition of the light transmittance of the liquid crystal display panel. FIG. 7 illustrates a case where the color intensities of red, green, blue, and white are 70%, 20%, 0%, and 30%, respectively, as in the above-described example.

 As shown in Fig. 7 (a), one frame period of an image signal is composed of four sub-frame periods, and the red, green, and blue light emitting diodes 23 R, 23 G, and 2 are provided for each sub-frame period. 3B sequentially emits light of a predetermined emission intensity to emit light of each color, and in the last subframe period of each frame period, the light emitting diodes 23R, 23G, and 23B are simultaneously emitted. Emit white light. A white light emitting diode is provided separately from the red, green, and blue light emitting diodes 23 R, 23 G, and 23 B, and the light emitting diodes emit light to emit white light. Is also good.

 Further, the light transmittance of the liquid crystal display panel 10 changes according to the image signal generated by the control circuit 36 as described above. Since the blue color intensity is 0%, black is displayed during the sub-frame period during which the blue light emitting diode 23B emits light. Therefore, as shown in FIG. 7 (b), the light transmittance of the liquid crystal display panel 10 becomes zero during the sub-frame period.

Thus, black is displayed during the sub-frame period during which the blue light emitting diode 23B emits light. Therefore, this subframe period In this case, a voltage corresponding to the black display signal is applied between each pixel electrode 40 and the counter electrode 6. In the case of the normally white mode liquid crystal display panel 10, the voltage corresponding to the black display signal is a relatively high voltage. Thus, in the case of the liquid crystal display device 1 of the present invention, a relatively high voltage is applied between each pixel electrode 40 and the counter electrode 6 in at least one sub-frame period in each frame period. . Therefore, it is possible to prevent the liquid crystal from being reversely transitioned from the bend alignment to the splay alignment. As a result, good image display can be stably performed.

 Further, as can be understood with reference to FIG. 6, in the case of the liquid crystal display device according to the first embodiment, a desired color is displayed using three colors located at close positions on the chromaticity coordinates. Color breakage can be reduced as compared with the conventional case.

The liquid crystal display device of the present invention displays a desired color using three colors that are close to each other on the chromaticity coordinates among the four or more colors, and in a subframe period related to a color not used for display. What is necessary is just to display black. Therefore, in the liquid crystal display device 1 of the first embodiment, an image is displayed using four colors of red, green, blue, and white, but the present invention is not limited to these four colors, and other colors may be used. It may be configured to display an image using a. In the case of the liquid crystal display device 1 according to the first embodiment, as shown in FIG. 7, black is displayed in one of the four sub-frame periods. In this case, if the length of each sub-frame period is the same, a voltage corresponding to the black display signal is applied between each pixel electrode 40 and the counter electrode 6 during 25% of one frame period. Will be done. In order to prevent reverse transition of the liquid crystal orientation from the bend orientation to the splay orientation, a voltage corresponding to the black display signal is applied to each pixel electrode 40 and the counter electrode during a period of 10% or more of one frame period. It has been confirmed that it is sufficient to apply the voltage between 6 and 6. Therefore, the liquid crystal display device 1 of the present embodiment has confirmed the reverse transition. Indeed, it can be prevented.

 Further, in the liquid crystal display device 1 of the first embodiment, the field sequential mode is realized by providing sub-frame periods for four colors of red, green, blue, and white, respectively. The sub-frame periods for the colors may be provided respectively. For example, an image may be displayed by providing subframe periods for seven colors of red, green, blue, cyan, magenta, yellow, and white, and sequentially displaying these colors in a time-division manner. In this case, if the blue and green light emitting diodes are displayed when displaying cyan, the blue and red light emitting diodes are displayed when displaying magenta, and the green and red light emitting diodes are displayed simultaneously when displaying yellow. Good. In this case, black is displayed in at least one of the seven sub-frame periods. Therefore, assuming that the length of each sub-frame period is the same, the voltage corresponding to the black display signal is equal to that of each pixel electrode 40 in about 14% (= 1/7) of one frame period. Since the voltage is applied between the counter electrode 6 and the counter electrode 6, the reverse transition can be prevented. In the case of the present invention, the sub-frame period in which each pixel displays black may be different depending on the image to be displayed. However, even when black is displayed in different subframe periods in adjacent pixels, the effect of preventing reverse transition does not change.

By the way, as described above, in the liquid crystal display device 1 according to the first embodiment, based on an image signal input from an external device, images related to two colors of red, green, and blue and three colors of white are provided. Generating a signal. At this time, it was decided on the liquid crystal display device 1 side which of the two colors of red, green and blue was to be used. However, for example, it is determined in advance whether the external device uses two colors of red, green, and blue, and information indicating the two colors is transmitted to the liquid crystal display device together with the image signal. May be. Such a method can be applied particularly to digital television broadcasting and the like. In this case, LCD display measures 1 Since the processing on the side is simplified, the display processing can be speeded up. A personal computer can be considered as the external device described above. In that case, the video port provided in the personal computer can determine which of the two colors red, green, and blue to use based on the image signal displayed on the liquid crystal display device.

 Further, in the present invention, when the voltage at which the bend alignment is more stable than the splay alignment is defined as the critical voltage Vc, a voltage equal to or lower than the critical voltage Vc is applied between the pixel electrode and the counter electrode. An image may be displayed by applying the voltage. As described above, even when a voltage lower than the critical voltage Vc is used for display, in the present invention, a relatively high voltage used for black display is applied in at least one subframe period. . Reverse metastasis can be prevented.

 (Embodiment 2)

 The liquid crystal display device of the present invention according to Embodiment 1 described above can be used as a display device of various devices such as a monitor for a personal computer, a television receiver, a micro display, a head mounted display, and a projector. it can.

 In particular, in the case of the field sequential color liquid crystal display device as in the present invention, in order to minimize the effect of image degradation due to color breakup, a viewfinder of a digital video camera, a mobile phone, and It is suitable to be used for electronic equipment having a small display unit, such as a portable terminal device such as a PDA (Personal Digital Assistant). FIG. 8 is a diagram showing the appearance of a device provided with the liquid crystal display device according to the first embodiment of the present invention, wherein (a) shows a digital video camera, and (b) shows a mobile phone. ing.

As shown in FIG. 8 (a), the digital video camera 51 has a viewfinder 50. And this viewfinder 50 The liquid crystal display device according to the first embodiment of the present invention includes the liquid crystal display device. In addition, as shown in FIG. 8 (b), the mobile phone 52 has a display unit 53. The display unit 53 is similarly constituted by the liquid crystal display device according to the first embodiment of the present invention.

 Here, the digital video camera 51 outputs an image signal to the viewfinder 50, and the mobile phone 52 outputs an image signal to the display unit 53. Upon receiving the input of the image signal, the viewfinder 50 and the display unit 53 operate in the same manner as the liquid crystal display device of the present invention according to the first embodiment. As a result, color breakage can be reduced, and reverse transition can be prevented.

 From the above description, many modifications and other embodiments of the present invention are obvious to one skilled in the art. Accordingly, the above description is to be construed as illustrative only, and is provided for the purpose of teaching those skilled in the art the best mode of carrying out the invention. The structure and details of Z or function may be substantially changed without departing from the spirit of the invention.

 [Possibility of industrial use]

 The liquid crystal display device according to the present invention is useful as a display device for a liquid crystal television, a liquid crystal monitor, or a small electronic device such as a portable telephone and a viewfinder.

Claims

Scope of request 1. a first substrate having a plurality of pixel electrodes arranged in a matrix;  A second substrate facing the first substrate,  A liquid crystal layer composed of liquid crystal sandwiched between the first substrate and the second substrate;  A counter electrode provided on the first substrate or the second substrate; a lighting device having a light source that emits light of at least three colors, and irradiating the liquid crystal layer with light of a plurality of colors;  A driving unit that drives the liquid crystal by generating a potential difference between each of the pixel electrodes and the counter electrode, and adjusts a transmittance of light emitted from the lighting device in the liquid crystal layer;  Illuminating device control means for controlling the illuminating device so as to sequentially emit light of each of the plurality of colors in one frame period; and  With  An alignment state in a display state of the liquid crystal is different from an alignment state in a non-display state of the liquid crystal, and a predetermined voltage is applied between the pixel electrode and the counter electrode in the alignment state in the display state. Therefore, it is necessary to maintain the orientation state of the display state, The one-frame period includes four or more sub-frame periods, and controls the lighting device control means so that the lighting device irradiates one color light of the plurality of colors for each of the sub-frame periods. Selecting three colors from the plurality of colors based on an image signal corresponding to an image to be displayed, and irradiating the selected three colors of light with the lighting device in a sub-frame period. In between, a voltage corresponding to the image signal related to the sub-frame period is applied between each of the pixel electrodes and the counter electrode, and the sub-frame in which the illumination device emits light of a color other than the selected three colors is used. During the period, a voltage corresponding to a black display signal is applied between each of the pixel electrodes and the counter electrode to drive the liquid crystal and display an image corresponding to the image signal.  The voltage corresponding to the black display signal is equal to the predetermined voltage,  Liquid crystal display.  2. The lighting device has a light source that emits red, green, and blue light, respectively.  2. The liquid crystal display device according to claim 1, wherein the plurality of colors are four colors of red, green, blue, and white.  3. The length of a sub-frame period in which a voltage corresponding to the black display signal is applied between each of the pixel electrodes and the counter electrode is at least 10% of one frame period. A liquid crystal display device according to the item.  4. The liquid according to claim 1, wherein the light source is a light emitting diode. 5. The liquid crystal is a normally white mode and is an OCB mode liquid crystal, the alignment state in a display state of the liquid crystal is a bend alignment state, and the alignment state in a non-display state of the liquid crystal is a splay alignment state. The liquid crystal display device according to claim 1.  6. An electronic apparatus, comprising: the liquid crystal display device according to claim 1; and configured to output an image signal to the liquid crystal display device.