JP2008191686A - Display device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device and a display method with which the efficiency of using light is improved without incurring deterioration of display image quality, especially reduction of luminance. <P>SOLUTION: One frame is divided into three sub-frames for red, green, and blue colors respectively. In each sub-frame, a time period (T<SB>A</SB>) required for write scanning, a time period (T<SB>C</SB>) required for erase scanning, a time period (T<SB>B</SB>) extending from a timing of finish of the write scanning to a timing of start of the erase scanning, and a time period (T<SB>D</SB>) extending from a timing of finish of the erase scanning to a timing of start of the write scanning of the next color (the next sub-frame) occupy 25% of the sub-frame. Equations TB+TC=TA+TD and TB=TD are satisfied. A backlight is turned on during the period between the timing of start of the write scanning and the timing of finish of the erase scanning, and is turned off during the period between the timing of finish of the erase scanning and the timing of start of the write scanning of the next color. A turning-on time period of the backlight occupies 75% of the sub-frame. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a field sequential display device and a display method for performing display by synchronizing switching of light of each color incident on an optical switching element and input of display data of each color corresponding to a display image to the optical switching element. And a color filter type display device for performing color display by synchronizing the incidence of white light to the optical switching element provided with the color filter and the input of display data of each color corresponding to the display image to the optical switching element, and It relates to the display method.

  With the progress of the so-called information society in recent years, electronic devices represented by personal computers, PDAs (Personal Digital Assistants) and the like have been widely used. With the spread of such electronic devices, there is a demand for portable devices that can be used both in the office and outdoors, and there is a demand for reduction in size and weight. Liquid crystal display devices are widely used as one of means for achieving such an object. A liquid crystal display device is an indispensable technology for reducing power consumption of a battery-driven portable electronic device as well as reducing the size and weight.

  Liquid crystal display devices are roughly classified into a reflection type and a transmission type. The reflective type is a configuration in which light incident from the front of the liquid crystal panel is reflected on the back of the liquid crystal panel and the image is visually recognized by the reflected light. The transmissive type is from a light source (backlight) provided on the back of the liquid crystal panel. In this configuration, an image is visually recognized with transmitted light. Since the reflective type does not have a constant amount of reflected light depending on environmental conditions and is inferior in visibility, in particular, as a display device such as a personal computer for performing multi-color or full-color display, a transmissive color liquid crystal using a color filter is generally used. A display device is in use.

  Currently, color liquid crystal display devices of a TN (Twisted Nematic) type using a switching element such as a TFT (Thin Film Transistor) are widely used. This TFT-driven TN type liquid crystal display device has a higher display quality than an STN (Super Twisted Nematic) type, but the light transmittance of the liquid crystal panel is currently only about 4%, so that a high screen brightness can be obtained. Requires a high-brightness backlight. For this reason, the power consumption by a backlight will become large. In addition, since color display using a color filter is used, one pixel must be composed of three sub-pixels, and it is difficult to achieve high definition, and the display color purity is not sufficient.

  In order to solve such a problem, the present inventors have developed a field sequential type liquid crystal display device (see, for example, Non-Patent Documents 1 and 2). This field-sequential liquid crystal display device does not require sub-pixels as compared with a color filter-type liquid crystal display device, so that it is possible to easily realize a display with higher accuracy and without using a color filter. In addition, since the emission color of the light source can be used as it is for display, the display color purity is excellent. Furthermore, since the light utilization efficiency is high, there is an advantage that less power consumption is required. However, in order to realize a field-sequential liquid crystal display device, high-speed response of liquid crystal (2 ms or less) is essential.

Therefore, the present inventors have established a field-sequential type liquid crystal display device or a color filter type liquid crystal display device having excellent advantages as described above in order to increase the response speed by 100 to 1000 as compared with the prior art. We are researching and developing driving of switching devices such as TFTs for liquid crystals such as ferroelectric liquid crystals having spontaneous polarization that can be expected to achieve double the speed response. As shown in FIG. 15, in the ferroelectric liquid crystal, the major axis direction of the liquid crystal molecules changes by a tilt angle θ by applying a voltage. A liquid crystal panel sandwiching a ferroelectric liquid crystal is sandwiched between two polarizing plates whose polarization axes are orthogonal to each other, and the transmitted light intensity is changed using birefringence due to a change in the major axis direction of liquid crystal molecules.

  FIG. 16 is an example of a time chart showing display control in a conventional field-sequential liquid crystal display device. FIG. 16A is a scanning timing of each line of the liquid crystal panel, and FIG. Indicates the lighting timing of red, green, and blue colors. One frame is divided into three subframes. For example, as shown in FIG. 16B, red is emitted in the first subframe, green is emitted in the second subframe, and the third subframe is emitted. Blue light is emitted in the frame.

  On the other hand, as shown in FIG. 16A, image data writing scanning and erasing scanning are performed on the liquid crystal panel in sub-frames of red, green and blue colors. However, the timing is adjusted so that the start timing of the write scan coincides with the start timing of each subframe, and the end timing of the erase scan coincides with the end timing of each subframe, and is required for the write scan and the erase scan. Each time is set to half of each subframe. In writing scanning and erasing scanning, voltages having the same magnitude and different polarities based on the same image data are applied to the liquid crystal panel. The light emission time of each color is equal to the time of the subframe (see, for example, Patent Document 1).

  Therefore, the amount of light actually used for display is about half of the amount of emitted light. This is because the time during which light is transmitted from the liquid crystal panel, which is an optical switching element, is only about half the time of the subframe. Strictly speaking, even after the erasure scan, the same image as that after the write scan is displayed with a much lower luminance than the image after the write scan, but it can be regarded as a “black display” substantially. The time for light to pass through the liquid crystal panel is about half the time of the subframe.

In the present specification, scanning for obtaining a display image with high luminance is called “writing scanning”, and scanning for obtaining an image with low luminance or a black image is called “erasing scanning”.
Toshiaki Yoshihara, et al. (T. Yoshihara, et. Al.): AM-LCD '99 Digest of Technical Papers, 185 pages, 1999 Toshiaki Yoshihara et al. (T.Yoshihara, et. Al.): SID'00 Digest of Technical Papers, 1176, 2000 JP 11-119189 A

  The field-sequential liquid crystal display device has the advantages of higher light utilization efficiency and lower power consumption than the color filter liquid crystal display device, but as described above. In addition, only about half of the light from the light source is used for display, and further improvement in light utilization efficiency is desired. Similarly, in a color filter type liquid crystal display device using a ferroelectric liquid crystal material, write scanning and erasing scanning are performed in half each time, so that the amount of light emitted from the light source is about There is a problem that only half is used for display.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a display device and a display method capable of improving light utilization efficiency without causing deterioration of display image quality, particularly luminance.

  The display device disclosed in the present application synchronizes sequential switching of light of a plurality of colors incident on a light switching element from a light source and input of display data of each color corresponding to a display image to the light switching element. In a field-sequential display device that performs display, means for injecting light of a corresponding color from the light source into the optical switching element in synchronization with the start timing of writing scanning of display data to the optical switching element in each color And means for blocking light of the corresponding color from the light source from entering the optical switching element in synchronization with the end timing of erasure scanning of display data on the optical switching element in each color, Start of the next color light entering the optical switching element from the timing of blocking the incident light of the next color to the optical switching element Characterized in that so as to provide a predetermined time until timing.

  The display method disclosed in the present application synchronizes sequential switching of light of a plurality of colors incident on a light switching element from a light source and input of display data of each color corresponding to a display image to the light switching element. In the display method for performing field sequential display, the light of the corresponding color from the light source is incident on the optical switching element in synchronization with the start timing of writing scanning of display data to the optical switching element in each color, In synchronization with the end timing of erasure scanning of display data on the optical switching element in each color, the light of the corresponding color from the light source is blocked from entering the optical switching element, and the optical switching of light of one color is performed. A predetermined period of time between the incident blocking timing on the element and the timing of starting the incident on the optical switching element of the next color And wherein the providing.

  In the display device and the display method disclosed in the present application, light of a corresponding color is incident on the optical switching element in synchronization with the start timing of writing scanning of display data to the optical switching element in each color, and the optical switching in each color is performed. The light of the corresponding color is blocked from entering the optical switching element in synchronization with the end timing of the erasure scanning of the display data on the element, and the incident of the light of one color to the optical switching element is blocked. A predetermined time is provided after the light is blocked until the next color light enters the optical switching element. The light emission time of the light source can be shortened in a state where the time for the light from the light source to pass through the optical switching element is kept equal to or longer than that in the conventional case, that is, without degrading the display image quality. As a result, the light use efficiency can be improved.

  In the display device disclosed in the present application, in the above-described display device, the predetermined time is from an end timing of writing scanning of display data to the optical switching element to a start timing of erasing scanning of display data to the optical switching element. It is characterized by being equal to time.

  In the display device disclosed in the present application, a predetermined period of time from when light of one color is blocked from entering the optical switching element to when light of the next color is incident on the optical switching element, The time is equal to the time from the end timing of writing scanning of display data to the switching element to the start timing of erasing scanning of display data to the optical switching element. Therefore, when a liquid crystal display element is used as the display element, it becomes easy to suppress a voltage deviation between + polarity and −polarity applied to the liquid crystal material, and display burn-in can be prevented.

The display device disclosed in the present application synchronizes sequential switching of light of a plurality of colors incident on a light switching element from a light source and input of display data of each color corresponding to a display image to the light switching element. In the field sequential type display device that performs display, the end timing of writing scanning of display data to the optical switching element in each color is inconsistent with the start timing of erasing scanning of display data to the optical switching element. The time required for scanning is T _A , the time from the end timing of writing scan to the start timing of erasing scan is T _B , the time required for erasing scan is T _C , and the time from the end timing of erasing scan to the optical switching element in the next color. the time until the start timing of writing scanning in the case of a T _D of the display data, T _B + T _C Characterized in that so as to satisfy a relation of T _A + T _D.

In the display device disclosed in the present application, the end timing of writing scanning of display data to the optical switching element in each color does not match the start timing of erasing scanning of display data to the optical switching element. The sum of the time (T _B ) from the end timing of the erase scan to the start timing of the erase scan and the time required for the erase scan (T _C ) is the next color from the time required for the write scan (T _A ) and the end timing of the erase scan. Is equal to the sum of the time (T _D ) until the write scanning start timing of display data to the optical switching element. Therefore, when a liquid crystal display element is used as the display element, the time during which the + polarity voltage is applied to the liquid crystal material is equal to the time during which the −polarity voltage is applied, and display burn-in can be suppressed.

  The display device disclosed in the present application synchronizes sequential switching of light of a plurality of colors incident on a light switching element from a light source and input of display data of each color corresponding to a display image to the light switching element. In a field sequential display device that performs display, means for causing light of a corresponding color from the light source to enter the optical switching element before the start timing of writing scanning of display data to the optical switching element in each color And means for blocking the incident of light of the corresponding color from the light source to the optical switching element after the end timing of erasure scanning of display data on the optical switching element in each color.

  In the display device disclosed in the present application, light of a corresponding color is incident on the optical switching element before the start timing of writing scanning of display data to the optical switching element in each color, and display on the optical switching element in each color Incident light to the optical switching element is blocked after the end timing of the data erasing scan. By doing so, the light of the corresponding color is surely incident on the optical switching element when the writing scan of the display data of each color is started, and it is reliably handled after the erasing scan of the display data of each color is completed. Incident light is blocked. Therefore, it is possible to increase a margin in the light emission sequence considering the response of the light source or in the driving synchronization in the light emission of the optical switching element and the light source.

  The display device disclosed in the present application is characterized in that, in any of the display devices described above, the light of a plurality of colors incident on the optical switching element is red light, green light, and blue light.

  In the display device disclosed in the present application, since the light of a plurality of colors incident on the optical switching element is red light, green light, and blue light, full-color display is possible. In the case of monochromatic display of red, green, and blue, it takes a long time to turn off the light source, and power consumption can be greatly reduced.

  The display device disclosed in the present application is characterized in that, in any one of the display devices described above, light of a plurality of colors incident on the optical switching element is red light, green light, blue light, and white light. .

In the display device disclosed in the present application, since the light of a plurality of colors incident on the optical switching element is red light, green light, blue light, and white light, full color display is possible. Further, the gradation numbers r, g, and b of the display data of red, green, and blue are set to r ′ = r−w, g ′ = g−, depending on the gradation number w of the display data of white that is the common part of the three colors. When converting to the number of gradations of display data of four colors w, b '= b-w, w, the number of gradations of white w is the lowest of the gradations r, g, b of red, green, and blue. Generally, the number of gradations is used, and at least one of the converted gradation numbers r ′, g ′, and b ′ is zero. Therefore, the probability that the light source can be turned off increases. In particular, in the case of black-and-white display, the light is lit only in the white sub-frame and is not lit in the red, green, and blue sub-frames, so that power consumption can be greatly reduced. Note that the power consumption can be significantly reduced in the case of red, green, and blue monochromatic display, similar to the display device described above.

  The display device disclosed in the present application further includes control means for controlling on / off of the light source that emits light of a color corresponding to display data based on display data in any of the display devices described above. Features.

  In the display device disclosed in the present application, lighting / non-lighting of the light source is controlled according to the number of gradations of display data in each color. Therefore, the power consumption can be reduced by turning off the light source when unnecessary.

  In the display device disclosed in the present application, in any of the display devices described above, the irradiation region of the light incident on the optical switching element is divided, and the display data corresponds to the display data based on the display data of the divided region. The apparatus further comprises control means for controlling turning on / off of the light source that emits light of a desired color.

  In the display device disclosed in the present application, lighting / non-lighting of the light source is controlled in accordance with the number of gradations of display data for each color for each divided irradiation region of light incident on the optical switching element. Accordingly, since finer control can be performed, the ratio of turning off the light source is increased, and the power consumption can be further reduced.

  The display device disclosed in the present application, in any of the display devices described above, stops the scanning process to the optical switching element when the light source that emits light of a color corresponding to display data is not lit. The apparatus further comprises means.

  In the display device disclosed in the present application, when the light source is not turned on, the drive control of the optical switching element is stopped. When the light source is not lit, the display screen is “black” for that color, so driving control of the optical switching element that is not necessary to perform “black” display can be suppressed, reducing power consumption. Can be planned.

  The display method disclosed in the present application synchronizes the incidence of white light from a light source to an optical switching element provided with a plurality of color filters and the input of display data of each color corresponding to a display image to the optical switching element. In the display method in which color display is performed, the light from the light source is incident on the optical switching element in synchronization with the start timing of writing scanning of the display data to the optical switching element, and the display data to the optical switching element The light from the light source is blocked from being incident on the optical switching element in synchronization with the end timing of the erasing scan, and the light in the next frame is determined from the timing at which the light switching element is incident on the first frame. A predetermined time is provided until the incident start timing to the switching element.

  The characteristics of the display device and the display method described above are not limited to the field sequential display device and display method, and a plurality of colors (red, green, blue) color filters are provided on the optical switching element (liquid crystal panel). The present invention can also be applied to a color filter type display device and display method in which white light is incident on a light switching element (liquid crystal panel) from a light source to perform color display.

In the present invention, the optical switching element is a liquid crystal panel, and power consumption at the light source in the liquid crystal display device is suppressed. In the case of a liquid crystal display device, the power consumption of the light source in the total power consumption is about 80%, so the effect of the present invention that can suppress the power consumption of the light source is to reduce the power consumption in the liquid crystal display device. Greatly contribute. In addition, by using a ferroelectric liquid crystal material as a liquid crystal material, a high-speed response of 2 ms or less necessary for a field-sequential liquid crystal display device is realized, and stable display is performed. In addition, the voltage applied to the liquid crystal panel in the erase scan is equal in magnitude to the voltage applied to the liquid crystal panel in the write scan, and the polarity is inverted. Therefore, voltage deviation due to voltage application to the liquid crystal panel is suppressed, and display burn-in can be prevented.

  In the present invention, since a predetermined time is provided between the time when the light of one color is blocked from being incident on the optical switching element until the light of the next color from the light source is incident on the optical switching element, In a state in which the time for the light from the light source to pass through the optical switching element is kept equal to or higher than that in the past, that is, the display image quality is not deteriorated, and particularly the luminance is not reduced, the light emission time of the light source can be shortened It is possible to improve light utilization efficiency in a field sequential display device. Similarly, in the color filter type display device, the light use efficiency can be improved.

  The present invention will be specifically described with reference to the drawings showing embodiments thereof. In the following, a liquid crystal display device in which the optical switching element is a liquid crystal panel will be described as an example. However, the present invention is not limited to the following embodiment.

(First embodiment)
FIG. 1 is a block diagram showing a circuit configuration of the liquid crystal display device according to the first embodiment, FIG. 2 is a schematic sectional view of a liquid crystal panel and a backlight, and FIG. 3 is a schematic diagram showing an example of the overall configuration of the liquid crystal display device. FIG. 4 is a diagram illustrating a configuration example of an LED array that is a light source of a backlight.

  In FIG. 1, reference numerals 21 and 22 denote a liquid crystal panel and a backlight whose cross-sectional structure is shown in FIG. As shown in FIG. 2, the backlight 22 includes an LED array 7 that emits red, green, and blue light and a light guide and light diffusion plate 6.

  As shown in FIG. 2 and FIG. 3, the liquid crystal panel 21 includes a polarizing film 1, a glass substrate 2, a common electrode 3, a glass substrate 4, and a polarizing film 5 from the upper layer (front surface) side to the lower layer (back surface) side. .. Are formed in this order, and pixel electrodes (pixel electrodes) 40, 40... Arranged in a matrix are formed on the surface of the glass substrate 4 on the common electrode 3 side.

  A driving unit 50 including a data driver 32 and a scan driver 33 is connected between the common electrode 3 and the pixel electrodes 40. The data driver 32 is connected to a TFT (Thin Film Transistor) 41 via a signal line 42, and the scan driver 33 is connected to the TFT 41 via a scanning line 43. The TFT 41 is on / off controlled by the data driver 32 and the scan driver 33. The individual pixel electrodes 40, 40... Are connected to the TFT 41. Therefore, the transmitted light intensity of each pixel is controlled by a signal from the data driver 32 given via the signal line 42 and the TFT 41.

  An alignment film 12 is disposed on the upper surface of the pixel electrodes 40, 40... On the glass substrate 4, and an alignment film 11 is disposed on the lower surface of the common electrode 3, and a liquid crystal material is filled between the alignment films 11 and 12. A liquid crystal layer 13 is formed. Reference numeral 14 denotes a spacer for maintaining the layer thickness of the liquid crystal layer 13.

The backlight 22 is located on the lower layer (rear) side of the liquid crystal panel 21, and the LED array 7 is provided in a state where the backlight 22 faces the end face of the light guide and light diffusion plate 6 constituting the light emitting region. As shown in FIG. 4, the LED array 7 emits light of three primary colors, that is, red (R), green (G), and blue (B) on the surface facing the light guide and light diffusion plate 6. The LEDs are arranged sequentially and repeatedly. The red, green, and blue LEDs are turned on in the red, green, and blue sub-frames, respectively, and the red, green, and blue LEDs are turned on simultaneously in the white sub-frame. The light guide and light diffusing plate 6 functions as a light emitting region by guiding light emitted from each LED of the LED array 7 to its entire surface and diffusing it to the upper surface.

  The liquid crystal panel 21 and a backlight 22 capable of time division light emission of red, green, and blue are overlapped. The lighting timing and emission color of the backlight 22 are controlled in synchronization with the writing scan / erasure scanning of the image data on the liquid crystal panel 21.

  In FIG. 1, reference numeral 31 denotes a control signal generation circuit that receives a synchronization signal SYN from a personal computer and generates various control signals CS necessary for display. Pixel data PD is output from the image memory unit 30 to the data driver 32. Based on the pixel data PD and the control signal CS for changing the polarity of the applied voltage, a voltage having a different polarity and a substantially equal voltage is applied to the liquid crystal panel 21 via the data driver 32 during the data write scan and the data erase scan. Applied each time.

  A control signal CS is output from the control signal generation circuit 31 to the reference voltage generation circuit 34, the data driver 32, the scan driver 33, and the backlight control circuit 35, respectively. The reference voltage generation circuit 34 generates reference voltages VR1 and VR2, and outputs the generated reference voltage VR1 to the data driver 32 and the reference voltage VR2 to the scan driver 33, respectively. The data driver 32 outputs a signal to the signal line 42 of the pixel electrode 40 based on the pixel data PD from the image memory unit 30 and the control signal CS from the control signal generation circuit 31. In synchronization with the output of this signal, the scan driver 33 sequentially scans the scanning lines 43 of the pixel electrodes 40 line by line. The backlight control circuit 35 applies drive voltage to the backlight 22 and causes the LEDs of the red, green, and blue colors included in the LED array 7 of the backlight 22 to emit light in a time-sharing manner.

  Next, the operation of the liquid crystal display device according to the present invention will be described. When pixel data PD for display is input from the personal computer to the image memory unit 30, the image memory unit 30 temporarily stores the pixel data PD and then receives the control signal CS output from the control signal generation circuit 31. In addition, the pixel data PD is output. The control signal CS generated by the control signal generation circuit 31 is supplied to the data driver 32, the scan driver 33, the reference voltage generation circuit 34, and the backlight control circuit 35. When receiving the control signal CS, the reference voltage generation circuit 34 generates reference voltages VR1 and VR2, and outputs the generated reference voltage VR1 to the data driver 32 and the reference voltage VR2 to the scan driver 33, respectively.

  When receiving the control signal CS, the data driver 32 outputs a signal to the signal line 42 of the pixel electrode 40 based on the pixel data PD output from the image memory unit 30. When receiving the control signal CS, the scan driver 33 sequentially scans the scanning lines 43 of the pixel electrodes 40 line by line. The TFT 41 is driven in accordance with the output of the signal from the data driver 32 and the scan of the scan driver 33, a voltage is applied to the pixel electrode 40, and the transmitted light intensity of the pixel is controlled.

  When receiving the control signal CS, the backlight control circuit 35 applies a drive voltage to the backlight 22 to time-divide the red, green, and blue LEDs of the LED array 7 of the backlight 22. Light is emitted, and red light, green light, and blue light are sequentially emitted over time.

Hereinafter, specific examples will be described. After the TFT substrate having the pixel electrodes 40, 40... (Pixel number 640 × 480, electrode area 6 × 10 ⁻⁵ cm ² , diagonal 3.2 inches) and the glass substrate 2 having the common electrode 3 are washed, polyimide Was applied and baked at 200 ° C. for 1 hour to form about 200 mm of polyimide film as alignment films 11 and 12. Further, these alignment films 11 and 12 are rubbed with a rayon cloth, these two substrates are overlapped so that the rubbing directions are parallel, and a silica spacer with an average particle diameter of 1.6 μm is placed between them. A blank panel was produced by superposing the gaps at 14 while maintaining the gap. Between the alignment films 11 and 12 of this empty panel, a liquid crystal layer 13 was formed by encapsulating a ferroelectric liquid crystal material having naphthalene-based liquid crystal as a main component and exhibiting a bistable electro-optical response. The spontaneous polarization of the sealed liquid crystal material was 8 nC / cm ² . The produced panel is sandwiched between two polarizing films 1 and 5 in a crossed Nicol state to form a liquid crystal panel 21, and an average molecular axis of a liquid crystal molecular director and a polarizing axis of one polarizing film when a voltage of one polarity is applied. Were substantially matched so as to be in a dark state.

  The liquid crystal panel 21 manufactured in this manner and the backlight 22 using the LED array 7 capable of single-color surface emission switching of red, green, and blue as a light source are overlapped, and field sequential is performed according to a drive sequence as described later. Color display by the method was performed.

  FIG. 5 is a time chart showing display control in the first embodiment. FIG. 5 (a) shows the scanning timing of each line of the liquid crystal panel 21, and FIG. 5 (b) shows the red of the backlight 22 (LED). Indicates the on / off timing of green and blue colors. One frame is divided into three sub-frames. For example, the red LED is turned on in the first sub-frame in one frame to perform writing / erasing scanning of red image data, and the next second sub-frame. The green LED is turned on to perform writing / erasing scanning of green image data, and the blue LED is turned on in the last third subframe to perform writing / erasing scanning of blue image data.

In each subframe, the time required for the write scan (T _A ) and the time required for the erase scan (T _C ) are both 25% of the subframe, and the time from the end timing of the write scan to the start timing of the erase scan ( T _B ) is 25% of the subframe, and the time (T _D ) from the end timing of the erasure scan to the start timing of the write scan in the next color (next subframe) is 25% of the subframe. Therefore, the relationship of T _B + T _C = T _A + T _D and T _B = T _D is satisfied.

The backlight 22 (LED) is turned on between the write scan start timing and the erase scan end timing, and the write scan start timing for the next color (next subframe) from the erase scan end timing. Turns off until As a result, the lighting time (= T _A + T _B + T _C ) of the backlight 22 is 75% of the subframe.

  Note that the voltage applied to the liquid crystal of each pixel in the writing scan and the erasing scan is a voltage of opposite polarity and substantially equal in magnitude so that a higher light transmittance can be obtained in the writing scan. The polarity of the applied voltage was adjusted. The frame frequency was 60 Hz.

As a result of displaying in this way, a screen luminance of 176 cd / m ² was realized with respect to the luminance of 1850 cd / m ² of the backlight alone. Therefore, the light use efficiency was as high as 9.5%. Further, the power consumption of the backlight at this time was 1.1 W.

Using a similar liquid crystal panel and the backlight in the first embodiment, in the conventional driving sequence (each subframe as shown in FIG. 16, the time required for writing scanning (T _A) and erasing scanning time required ( T _C ) is 50% of the sub-frame, and the time from the write scan end timing to the erase scan start timing (T _B ) and the erase scan end timing in the next color (next sub-frame) Color display was performed according to the time (T _D ) until the start timing of the writing scan was 0%. A screen luminance of 174cd / m ² to the backlight single luminance 2465cd / m ^2, the light utilization efficiency was as low as 7.1%.
In addition, the power consumption of the backlight at this time was as large as 1.5 W.

  When the image quality in display between the first embodiment based on FIG. 5 and the conventional example based on FIG. 16 was compared, no difference was felt between the two. On the contrary, in the first embodiment having the time when the backlight is turned off, the black luminance is lowered and the contrast ratio is improved by about 1.3 times as compared with the conventional example. In addition, the color mixture was suppressed by improving the contrast ratio, and the display color purity was improved.

(Second Embodiment)
In the first embodiment, a liquid crystal material to be used and a second embodiment in which T _A , T _B , T _C , and T _D are different will be described. Since the circuit configuration and operation of the liquid crystal display device are the same as those in the first embodiment, description thereof will be omitted.

First, an empty panel was produced exactly as in the first embodiment. A ferroelectric liquid crystal material showing an isotropic phase-cholesteric phase-chiral smectic C phase transition sequence from the high temperature side and showing a monostable electro-optic response is enclosed between the alignment films 11 and 12 of this empty panel. The liquid crystal layer 13 was used, and alignment treatment was performed by applying DC 10 V to the liquid crystal layer 13 at a transition temperature of ± 3 ° C. (100 to 94 ° C.) from the cholesteric phase to the chiral smectic C phase. In the alignment treatment, the temperature of the liquid crystal was once raised to the isotropic phase (120 ° C.), the subsequent cooling rate was fixed at −1 ° C./min, and the solution was cooled to room temperature (25 ° C.). Uniform liquid crystal alignment could be obtained by such alignment treatment. The spontaneous polarization of the sealed liquid crystal material was 11 nC / cm ² . The produced panel is sandwiched between two polarizing films 1 and 5 in a crossed Nicol state to form a liquid crystal panel 21, and the average molecular axis of the liquid crystal molecular director when no voltage is applied and the polarizing axis of one of the polarizing films are substantially matched. To make it dark.

  The liquid crystal panel 21 manufactured in this manner and the backlight 22 using the LED array 7 capable of single-color surface emission switching of red, green, and blue as a light source are overlapped, and field sequential is performed according to a drive sequence as described later. Color display by the method was performed.

  FIG. 6 is a time chart showing display control in the second embodiment. FIG. 6A shows scanning timing of each line of the liquid crystal panel 21, and FIG. 6B shows red of the backlight 22 (LED). Indicates the on / off timing of green and blue colors.

In each subframe obtained by dividing one frame into three, the time required for the write scan (T _A ) and the time required for the erase scan (T _C ) are both 20% of the subframe. The time to start timing (T _B ) is 30% of the subframe, and the time (T _D ) from the end timing of erasing scan to the start timing of write scan in the next color (next subframe) is sub 30% of the frame. Therefore, the relationship of T _B + T _C = T _A + T _D and T _B = T _D is satisfied.

Similarly to the first embodiment, the backlight 22 (LED) is lit between the write scan start timing and the erase scan end timing, and the next color (next subframe) from the erase scan end timing. The light is turned off until the start timing of the writing scan at (1). As a result, the lighting time (= T _A + T _B + T _C ) of the backlight 22 is 70% of the subframe.

  Note that the voltage applied to the liquid crystal of each pixel in the writing scan and the erasing scan is a voltage of opposite polarity and substantially equal in magnitude so that a higher light transmittance can be obtained in the writing scan. The polarity of the applied voltage was adjusted. The frame frequency was 60 Hz.

As a result of displaying in this manner, a screen luminance of 183 cd / m ² was realized with respect to the luminance of the backlight alone, 1725 cd / m ² . Therefore, the light utilization efficiency was as high as 10.6%. In addition, the power consumption of the backlight at this time was as small as 1.0 W.

Using the same liquid crystal panel and backlight as in the second embodiment, color display was performed according to the driving sequence as shown in FIG. A screen luminance of 179cd / m ² to the backlight single luminance 2465cd / m ^2, the light utilization efficiency was as low as 7.3%. In addition, the power consumption of the backlight at this time was as large as 1.5 W.

  When the image quality in display between the second embodiment based on FIG. 6 and the conventional example based on FIG. 16 was compared, no difference was felt between the two. On the contrary, in the second embodiment having a time during which the backlight is turned off, the black luminance is lowered and the contrast ratio is improved by about 1.4 times compared to the conventional example. In addition, the color mixture was suppressed by improving the contrast ratio, and the display color purity was improved.

(Third embodiment)
_A description will be given of a third embodiment in which the values of T _A , T _B , T _C , and T _D are the same as in the first embodiment, but the backlight lighting time is different. Since the circuit configuration and operation of the liquid crystal display device are the same as those in the first embodiment, description thereof will be omitted. The configuration of the liquid crystal panel including the liquid crystal material to be used is the same as that of the first embodiment.

  FIG. 7 is a time chart showing display control in the third embodiment. FIG. 7A shows scanning timing of each line of the liquid crystal panel 21, and FIG. 7B shows red of the backlight 22 (LED). Indicates the on / off timing of green and blue colors.

In each sub-frame obtained by dividing one frame into three, the time required for the write scan (T _A ), the time required for the erase scan (T _C ), and the time from the end timing of the write scan to the start timing of the erase scan (T _B ) The time (T _D ) from the end timing of the erase scan to the start timing of the write scan in the next color (next subframe) is 25% of the subframe, as in the first embodiment. is there.

However, the timing of turning on / off the backlight 22 (LED) is different from that of the first embodiment. In the first embodiment, the lighting start timing of the backlight 22 and the writing scanning start timing are matched, and the backlight 22 extinguishing start timing and the erasing scanning end timing are matched. In this embodiment, the lighting start timing of the backlight 22 is set earlier by a predetermined time (T _E ) than the write scanning start timing, and the backlight 22 extinguishing start timing is set by a predetermined time (T _F) from the erase scanning end timing. ) Only late.

In the example shown in FIG. 7, these predetermined times (T _E , T _F ) are all 5% of the subframe. Therefore, the lighting time of the backlight 22 (= T _E + T _A + T _B + T _C + T _F ) is 85% of the subframe.

  Note that the voltage applied to the liquid crystal of each pixel in the writing scan and the erasing scan is a voltage of opposite polarity and substantially equal in magnitude so that a higher light transmittance can be obtained in the writing scan. The polarity of the applied voltage was adjusted. The frame frequency was 60 Hz.

As a result of displaying in this manner, a screen luminance of 177 cd / m ² was realized with respect to the luminance of the backlight alone, 2096 cd / m ² . Therefore, the light utilization efficiency was as high as 8.4%. In addition, the power consumption of the backlight at this time was 1.2 W.

  When the image quality in the display of the third embodiment based on FIG. 7 and the conventional example based on FIG. 16 was compared, no difference was felt between the two. On the contrary, in the first embodiment having a time when the backlight is turned off, the black luminance is lowered and the contrast ratio is improved by about 1.2 times as compared with the conventional example. In addition, the color mixture was suppressed by improving the contrast ratio, and the display color purity was improved.

(Fourth embodiment)
Red, green, and blue display data is detected, and for each subframe in which all display data in each color is black (the number of gradations of all display data is approximately 0), a corresponding color light source (LED ) Is not lit, and the fourth embodiment in which data scanning with respect to the liquid crystal panel is not performed will be described. In the example of the present invention, the display becomes brighter as the number of gradations of the pixel data increases. When the number of gradations is approximately 0, the display is “black” display.

  FIG. 8 is a block diagram showing a circuit configuration of the liquid crystal display device according to the fourth embodiment. In FIG. 8, the same or similar members as those in FIG. The liquid crystal panel in the fourth embodiment is the same as that in the second embodiment, including the liquid crystal material used.

  In FIG. 8, reference numeral 23 denotes pixel data PD for display from an external personal computer, for example, and a gradation number detection circuit 24 detects the number of gradations for each color (red, green, blue), and 24 is detected. It is a lighting / non-lighting control unit that controls lighting / non-lighting of LEDs corresponding to each color (red, green, blue) based on the number of gradations.

  The lighting / non-lighting control unit 24 has substantially zero gradation levels of all pixel data PD of each color (red, green, blue) corresponding to each subframe detected by the gradation number detection circuit 23. In this case, the non-lighting signal is output to the backlight control circuit 35 and the control signal generation circuit 31. When the non-lighting signal is input, the backlight control circuit 35 turns off the LED in the subframe corresponding to the color. Further, when this non-lighting signal is input, the control signal generation circuit 31 stops driving the liquid crystal panel 21 without sending out the control signal CS.

  FIG. 9 is a time chart showing display control in the fourth embodiment. FIG. 9A shows scanning timing of each line of the liquid crystal panel 21, and FIG. 9B shows red of the backlight 22 (LED). Indicates the on / off timing of green and blue colors.

  The drive sequence for the liquid crystal panel in the fourth embodiment is basically the same as the drive sequence in the second embodiment (FIG. 6). However, when the gradation number detection circuit 23 detects the gradation number of each color (red, green, blue) in the display data, and the detected gradation number of all the pixel data in the subframe is substantially zero. In addition, a non-lighting signal is sent from the lighting / non-lighting control unit 24 to the backlight control circuit 35, so that all pixel data in each color are subframes in which the number of gradations of all pixel data in each color is approximately 0. In the “black” sub-frame, the LED corresponding to the color is not lit, and a non-lighting signal is sent from the lighting / non-lighting control unit 24 to the control signal generation circuit 31 to stop driving the liquid crystal panel 21. .

In the display according to the fourth embodiment, a screen luminance of 183 cd / m ² can be realized with respect to the luminance of the backlight alone, 1725 cd / m ² . Therefore, the light utilization efficiency was as high as 10.6%. In addition, the power consumption of the backlight at this time was as small as 1.0 W.

It should be noted that the power consumption of the backlight is 1 for full color display such as natural images and monochrome display.
. Although it was 0W, in single color display (red black, green black, blue black display, etc.), it was possible to further reduce power consumption by not turning on the backlight based on the detection result of the display data. In the green-black display, the power consumption was as low as 0.28W.

  When the display is performed according to the conventional driving sequence in which the LEDs are always lit in each of the red, green, and blue subframes without detecting the number of gradations of the display data of red, green, and blue as in the fourth embodiment In addition to full color display and black and white display of natural images, etc., power consumption of 1.0 W was required not only for single color display (red black, green black, and blue black display). In addition, when the image quality in the display of 4th Embodiment and a prior art example was compared, difference was not felt in both.

(Fifth embodiment)
In the fifth embodiment, input red, green, and blue pixel data is converted into red, green, blue, and white pixel data, and the converted four-color pixel data is used for full color. Display. First, this conversion method will be described.

  FIG. 10A shows the original number of gradations of red (r), green (g), and blue (b) in each frame, and FIG. 10 (b) shows the converted red (r ′) in each frame. ), Green (g ′), blue (b ′), and white (w). In each frame, the minimum number of gradations is detected by comparing the number of gradations of red, green, and blue pixel data. For example, in the first frame shown in FIG. 10A, the number of gray levels of green display data is the lowest. In this case, in the red and blue display sub-frames, the number of gradations (r ′ = r−−) obtained by subtracting the number of gradations of green (g) from the number of gradations of red and blue (r, b) before comparison. g, b ′ = b−g), red display and blue display are performed.

  In the white display subframe, which is a mixed color of red, green, and blue, white display (w = g) corresponding to the number of green gradations (g) is performed. In the green display sub-frame, the green display corresponding to the gradation number (g ′ = g−g) obtained by subtracting the green gradation number (g) from the green gradation number (g) before the comparison is performed. However, since the subtracted number of gradations (g ′) is 0, this is generally “black” display.

  In the fifth embodiment, the green LED is turned off in the green sub-frame displaying “black”. In such a conversion process, since the number of gradations after conversion of at least one color is 0, the probability that the light source can be turned off is greater than in the fourth embodiment, and the power consumption is further reduced. Can be realized.

  Furthermore, in the fifth embodiment, the irradiation area of light incident on the liquid crystal panel is divided into a plurality of areas, and a light source corresponding to each color according to the number of gradations of pixel data of each color for each divided area. Controls lighting / non-lighting of (LED).

  As shown in FIG. 11, the region of the backlight 22 is divided into five small regions 22a to 22e, whereby the light irradiation region to the liquid crystal panel 21 is divided into five small irradiation regions. In addition to controlling lighting / non-lighting of each color LED in synchronization with scanning of the liquid crystal panel 21, the number of gradations of pixel data of red, green, blue, and white is detected for each small irradiation region. Then, when the number of gradations of all pixel data in the small irradiation area in each color is approximately 0, the LED corresponding to that color in the small irradiation area is not lit.

  FIG. 12 is a block diagram showing a circuit configuration of the liquid crystal display device according to the fifth embodiment. 12, the same or similar members as those in FIGS. 1 and 8 are denoted by the same reference numerals. The configurations of the liquid crystal panel and the backlight are the same as those in the first embodiment. In the white subframe, the red, green, and blue LEDs in the LED array 7 are turned on simultaneously.

  In FIG. 12, reference numeral 25 denotes a pixel data conversion circuit 25 that converts three-color pixel data PD for display input from an external personal computer, for example, into four-color pixel data PD ′ for display according to the above-described method. The pixel data conversion circuit 25 outputs the converted pixel data PD ′ to the gradation number detection circuit 23 and the image memory unit 30. The gradation number detection circuit 23 detects the number of gradations of each color (red, green, blue, white) for each of the five small irradiation areas of the liquid crystal panel 21, and sends the detection result to the lighting / non-lighting control unit 24. send. The lighting / non-lighting control unit 24 determines the number of gradation levels of all the converted pixel data PD ′ of each color (red, green, blue, white) corresponding to each subframe detected by the gradation number detection circuit 23. When it is substantially 0, a non-lighting signal is output to the backlight control circuit 35 and the control signal generation circuit 31. The backlight control circuit 35 emits red, green, blue, and white colored light from the backlight 22 in each small irradiation area. When this non-lighting signal is input, each small irradiation corresponding to the color is performed. The LED is not lit in the area. Further, when this non-lighting signal is input, the control signal generation circuit 31 stops driving the liquid crystal panel 21 without sending out the control signal CS.

  Note that the configuration and operation of other members such as the control signal generation circuit 31, the data driver 32, the scan driver 33, and the reference voltage generation circuit 34 only change the pixel data PD to the converted pixel data PD ′. , Which is basically the same as that of the fourth embodiment, the description thereof is omitted.

  FIG. 13 is a time chart showing display control in the fifth embodiment. FIG. 13A shows scanning timing of each line of the liquid crystal panel 21, and FIG. 13B shows red of the backlight 22 (LED). Indicates the lighting / non-lighting timing of each color of green, blue, and white. In each subframe in which one frame having a frequency of 60 Hz is divided into four, the timing of data write scan / erase scan with respect to the liquid crystal panel 21 is the same as in the third embodiment. However, as shown in FIG. 13B, the lighting / non-lighting of the backlight 22 is controlled for each of the five small irradiation areas in one subframe. When a non-lighting signal is input for a small irradiation region having a color, the LED is not lighted in the small irradiation region of that color, and the color is not emitted. The lighting time of the backlight 22 in each small irradiation region is shorter than 70% of the subframe.

  In exactly the same manner as in the second embodiment described above, a liquid crystal panel 21 is manufactured, and the backlight 22 using the manufactured liquid crystal panel 21 and an LED array 7 capable of monochromatic surface emission switching of red, green, and blue as a light source. And the color display by the field sequential method was performed according to the driving sequence shown in FIG. In the white subframe, red, green, and blue LEDs were turned on simultaneously.

  The number of gradations detection circuit 23 detects the number of gradations of each color (red, green, blue, white) in the converted display data for each small irradiation region, and all the conversions detected in each small irradiation region. When the number of gradations of the pixel data is substantially zero, a non-lighting signal is sent from the lighting / non-lighting control unit 24 to the backlight control circuit 35, and the number of gradations of all the converted pixel data in each color is substantially zero. In a small irradiation region, in other words, in a small irradiation region in which all converted pixel data is “black” in each color, the LED corresponding to that color is not lit. In addition, when the number of gradations of all the converted pixel data detected in each small irradiation area is approximately 0, a non-lighting signal is sent from the lighting / non-lighting control unit 24 to the control signal generation circuit 31, and the liquid crystal panel 21 is stopped.

As a result of such display, the power consumption of the backlight in a full color display such as a natural image was 1.7 W, but in the monochrome display, the power consumption was 0.9 W, and the monochrome color display (red black, green black, blue black display) ), The power consumption was lower, and the green-black display was extremely low at 0.26 W. A screen luminance of 180 cd / m ² was realized with respect to a luminance of 1190 cd / m ² of the backlight alone in monochrome display, and the light use efficiency was high at 15.1%.

  As in the fifth embodiment, the backlight is divided into five small areas, but each of the red, green, blue, and white sub-data is detected without detecting the number of gradations of the display data of red, green, blue, and white. When displayed according to the conventional driving sequence in which the LED is always lit in the frame, 1.7 W is consumed not only in full color display and monochrome display of natural images etc., but also in single color display (red black, green black, blue black display). It took power.

  When the image quality in the display of the fifth embodiment and the conventional example was compared, there was no difference between them, and the display image quality in the fifth embodiment was not deteriorated compared to the conventional example. .

  In each of the above-described embodiments, a field sequential type liquid crystal display device using a liquid crystal panel as an optical switching element has been described as an example. However, other optical switching elements such as a digital micromirror device (DMD) are used. Of course, the present invention can be similarly applied to other display devices. Further, although the light source used is an LED light source, it is not particularly limited to an LED light source as long as it is a switchable light source such as an EL.

  Further, it goes without saying that the same effect can be obtained in a color display device using a color filter, particularly a color liquid crystal display device using a ferroelectric liquid crystal material. This is because in the color filter system, the present invention can be similarly applied if the liquid crystal panel is provided with the red, green, and blue emission colors in the above-described embodiments as white.

  FIG. 14 is a schematic cross-sectional view of a liquid crystal panel and a backlight in a liquid crystal display device using a color filter. 14, the same parts as those in FIG. 2 are denoted by the same reference numerals, and description thereof is omitted. Three color filters 60, 60,... Of three primary colors (R, G, B) are provided below the respective pixel electrodes (pixel electrodes) 40, 40,. Alternatively, a color filter is provided between the common electrode 3 and the glass substrate 2 facing each pixel electrode (pixel electrode) 40, 40. The backlight 22 includes a white light source 70 that emits white light and a light guide and light diffusion plate 6.

  In such a color filter type display device, the time required for data writing scanning and erasing scanning in each frame is made smaller than 50% of the frame, and light is incident on the liquid crystal panel in one frame. Specifically, by providing a predetermined time between the shut-off timing and the start timing of light incident on the liquid crystal panel in the next frame, specifically, the same control as the control in each subframe of the field sequential method described above is performed. By executing it in each frame, the light use efficiency can be improved without causing deterioration of the display image quality (brightness).

  The following additional notes are disclosed with respect to the first to fifth embodiments described above.

(Supplementary Note 1) A field for performing display by synchronizing sequential switching of light of a plurality of colors incident on a light switching element from a light source and input of display data of each color corresponding to a display image to the light switching element. In the sequential display device, means for injecting light of the corresponding color from the light source into the optical switching element in synchronization with the start timing of writing scanning of display data to the optical switching element in each color, Means for blocking incident light of the corresponding color from the light source to the optical switching element in synchronization with the end timing of the erasing scan of the display data to the optical switching element. From the incident blocking timing to the optical switching element to the incident start timing of the next color to the optical switching element Display device is characterized in that so as to provide a predetermined time.

(Additional remark 2) The said predetermined time is equal to the time from the completion | finish timing of the write scanning of the display data to the said optical switching element to the start timing of the erasing scanning of the display data to the said optical switching element, It is characterized by the above-mentioned. The display device described.

(Supplementary Note 3) A field that displays in synchronization with sequential switching of light of a plurality of colors incident on the optical switching element from the light source and input of display data of each color corresponding to the display image to the optical switching element. In the sequential type display device, the time required for writing scanning is different because the end timing of writing scanning of display data to the optical switching element in each color and the start timing of erasing scanning of display data to the optical switching element are inconsistent. T _A , T _{B is} the time from the end timing of the write scan to the start timing of the erase scan, T _{C is} the time required for the erase scan, and the display data to the optical switching element in the next color from the end timing of the erase scan The relationship of T _B + T _C = T _A + T _D , where T _D is the time until the write scan start timing A display device characterized by satisfying the above.

(Supplementary Note 4) A field for performing display by synchronizing sequential switching of light of a plurality of colors incident on a light switching element from a light source and input of display data of each color corresponding to a display image to the light switching element. In the sequential type display device, means for injecting light of the corresponding color from the light source into the optical switching element before the start timing of writing scanning of display data to the optical switching element in each color, and the color in each color A display device comprising: means for blocking incident light of the corresponding color from the light source to the optical switching element after the end timing of the erasure scanning of the display data to the optical switching element.

(Supplementary note 5) The display device according to any one of supplementary notes 1 to 4, wherein the light of a plurality of colors incident on the optical switching element is red light, green light, and blue light.

(Appendix 6) The display device according to any one of appendices 1 to 4, wherein the light of a plurality of colors incident on the optical switching element is red light, green light, blue light, and white light.

(Supplementary note 7) The control unit according to any one of supplementary notes 1 to 6, further comprising control means for controlling on / off of the light source that emits light of a color corresponding to the display data based on the display data. Display device.

(Additional remark 8) The irradiation area | region of the light which injects into the said optical switching element is divided | segmented, Based on the display data of the divided | segmented area | region, the lighting / extinction of the said light source which radiate | emits the light of the color corresponding to display data The display device according to any one of supplementary notes 1 to 6, further comprising control means for controlling the control.

(Additional remark 9) When the said light source which radiate | emits the light of the color corresponding to display data is made into non-lighting, the stop means which stops the scanning process to the said optical switching element is further provided, Additional remarks 1-8 characterized by the above-mentioned. The display apparatus in any one of.

(Supplementary note 10) The display device according to any one of supplementary notes 1 to 9, wherein the optical switching element is a liquid crystal panel.

(Supplementary note 11) The display device according to supplementary note 10, wherein the liquid crystal material used in the liquid crystal panel is a ferroelectric liquid crystal material.

(Additional remark 12) The applied voltage at the time of writing scanning of the display data with respect to the said liquid crystal panel and the applied voltage at the time of erasing scanning of the display data with respect to the said liquid crystal panel are magnitude | sizes, and polarity is opposite. Display device.

(Supplementary Note 13) A field sequential system in which sequential switching of light of a plurality of colors incident on a light switching element from a light source is synchronized with input of display data of each color corresponding to a display image to the light switching element In the display method for performing the display, the light of the corresponding color from the light source is incident on the optical switching element in synchronization with the start timing of writing scanning of display data to the optical switching element in each color, and the light in each color The light of the corresponding color from the light source is blocked from entering the optical switching element in synchronization with the end timing of the erasure scanning of the display data on the switching element, and the light of one color is incident on the optical switching element. Providing a predetermined time between the shut-off timing and the start timing of the next color to the optical switching element Display method and butterflies.

(Supplementary Note 14) Color display by synchronizing incidence of white light from a light source to a light switching element provided with a plurality of color filters and input of display data of each color corresponding to a display image to the light switching element In the display method, the light from the light source is incident on the optical switching element in synchronization with the start timing of writing the display data to the optical switching element, and the display data is erased and scanned on the optical switching element. The light from the light source is blocked from entering the optical switching element in synchronization with the end timing, and from the incident blocking timing to the optical switching element in one frame to the optical switching element in the next frame. A display method characterized by providing a predetermined time before the incident start timing.

It is a block diagram which shows the circuit structure of the liquid crystal display device (1st, 2nd, 3rd embodiment) of this invention. It is typical sectional drawing of a liquid crystal panel and a backlight. It is a schematic diagram which shows the structural example of the whole liquid crystal display device. It is a figure which shows the structural example of a LED array. It is a time chart which shows the display control in the liquid crystal display device (1st Embodiment) of this invention. It is a time chart which shows the display control in the liquid crystal display device (2nd Embodiment) of this invention. It is a time chart which shows the display control in the liquid crystal display device (3rd Embodiment) of this invention. It is a block diagram which shows the circuit structure of the liquid crystal display device (4th Embodiment) of this invention. It is a time chart which shows the display control in the liquid crystal display device (4th Embodiment) of this invention. It is a figure which shows the conversion example of the pixel data in the liquid crystal display device (5th Embodiment) of this invention. It is a figure which shows the example of a division | segmentation of the backlight in the liquid crystal display device (5th Embodiment) of this invention. It is a block diagram which shows the circuit structure of the liquid crystal display device (5th Embodiment) of this invention. It is a time chart which shows the display control in the liquid crystal display device (5th Embodiment) of this invention. It is typical sectional drawing of a liquid crystal panel and a backlight. It is a figure which shows the alignment state of the liquid crystal molecule in a ferroelectric liquid crystal panel. It is a time chart which shows the display control in the conventional liquid crystal display device.

Explanation of symbols

3 common electrode 7 LED array 21 liquid crystal panel 22 backlight 23 gradation number detection circuit 24 lighting / non-lighting control unit 25 pixel data conversion circuit 31 control signal generation circuit 35 backlight control circuit 60 color filter 70 white light source

Claims (8)

A field-sequential system that performs display by synchronizing the sequential switching of light of a plurality of colors incident on a light switching element from a light source and the input of display data of each color corresponding to a display image to the light switching element. in the display device, and the start timing of display data erasing scanning end timing of display data writing scanning on the optical switching element in each color to the optical switching element is a discrepancy, the time required for write scan T _a, The time from the end timing of the write scan to the start timing of the erase scan is T _B , the time required for the erase scan is T _C , and the start of the write scan of display data to the optical switching element in the next color from the end timing of the erase scan If the time from the timing was T _D, satisfy the relationship of _{T B + T C = T a} + T D A display device characterized by that.   A field-sequential system that performs display by synchronizing the sequential switching of light of a plurality of colors incident on a light switching element from a light source and the input of display data of each color corresponding to a display image to the light switching element. In the display device, means for injecting light of a corresponding color from the light source into the optical switching element before the start timing of writing scanning of display data to the optical switching element in each color, and to the optical switching element in each color A display device comprising: means for blocking incident light of the corresponding color from the light source to the optical switching element after the end timing of the erasure scanning of the display data.   The display device according to claim 1, wherein the light of a plurality of colors incident on the optical switching element is red light, green light, and blue light.   3. The display device according to claim 1, wherein the light of a plurality of colors incident on the optical switching element is red light, green light, blue light, and white light.   5. The display device according to claim 1, further comprising control means for controlling on / off of the light source that emits light of a color corresponding to the display data based on the display data.   Control for controlling lighting / extinguishing of the light source that emits light of a color corresponding to display data based on display data of the divided area, where an irradiation area of light incident on the optical switching element is divided The display device according to claim 1, further comprising means.   7. The apparatus according to claim 1, further comprising a stopping unit that stops a scanning process to the optical switching element when the light source that emits light of a color corresponding to display data is not turned on. The display device described in 1.   Display method for performing color display by synchronizing incidence of white light from a light source to an optical switching element provided with a plurality of color filters and input of display data of each color corresponding to a display image to the optical switching element , The light from the light source is incident on the optical switching element in synchronization with the start timing of writing scanning of display data to the optical switching element, and is synchronized with the end timing of erasing scanning of display data on the optical switching element. Then, the incidence of light from the light source on the optical switching element is interrupted, and from the incidence interruption timing on the optical switching element in one frame to the incidence start timing on the optical switching element in the next frame A display method characterized by providing a predetermined time between.

Images