JP2002221702A - Field sequential liquid crystal display - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To increase the light emission time from a light source without lowering the frame frequency, provide sufficient brightness, do not cause flickering in the display, and produce a high-quality moving image. Provided is a field sequential liquid crystal display device capable of displaying. A plurality of divided areas (2a, 2b, 2c, 2) obtained by dividing a screen area (2) of a liquid crystal display element (1) into a predetermined number of pixel rows.
d, a plurality of surface light sources 10a, 10b, 10c, and 10d that sequentially emit light of a plurality of unit colors are arranged, and a plurality of pixel rows of the liquid crystal display element 1 are arranged in a scanning period for each field. Image data of one unit color is sequentially written to the pixels of each row, and the surface light source corresponding to the divided area is turned off during the selection period of each pixel row of the plurality of divided areas for each of the fields. In the period between the selection period of the segmented region of the previous field and the next field, from the surface light source corresponding to the segmented region to the unit color image data written in the selection period of the previous field. Light of a corresponding color was emitted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a field sequential liquid crystal display device.

[0002]

2. Description of the Related Art In a field sequential liquid crystal display device, a plurality of pixels are arranged in a plurality of rows in a screen area, and a plurality of units are provided behind a liquid crystal display element for controlling transmission of light of these pixels. A light source for sequentially emitting light of different colors is arranged, and a plurality of the liquid crystal display elements are provided for each field for displaying one unit color among a plurality of unit colors for displaying an arbitrary color by mixing colors. A pixel row is sequentially selected, and image data of one of the plurality of unit colors is written to the pixels of each row, and correspondingly, light of a color corresponding to the unit color image data is emitted from the light source. Thus, a color image is displayed.

FIG. 3 is a timing chart of light emission from a light source in a conventional field-sequential liquid crystal display device. Here, three unit colors of red, green and blue are applied to pixels of a plurality of rows of a liquid crystal display element in one frame. An example is shown in which image data is sequentially written, and light of three colors of red, green, and blue is sequentially emitted from a light source in accordance with the image data to display a full-color image.

As shown in FIG. 3, a conventional field-sequential liquid crystal display device forms one color image.
The frame is composed of three continuous fields for displaying images of three unit colors of red, green, and blue. Each of these fields includes a scanning period for sequentially selecting all pixel rows of the liquid crystal display element. And a blanking period after the scanning period. During the scanning period of the first field, a plurality of pixel rows of the liquid crystal display element are sequentially selected, and red unit color image data is written to the pixels of each row, and thereafter, Red light is emitted from the light source, and during the scanning period of the second field, a plurality of pixel rows of the liquid crystal display element are sequentially selected to write green unit color image data to the pixels of each row, and thereafter, the green light is emitted from the light source. A light is emitted, a plurality of pixel rows of the liquid crystal display element are sequentially selected during a scanning period of the third field, blue unit color image data is written to the pixels of each row, and then blue light is emitted from the light source. This By, red, green, in order to display the unit color image of the blue, to display a full-color image that looks overlap these unit color image.

As described above, the conventional field-sequential liquid crystal display device is configured to emit red, green, and blue light from a light source using the retrace period, as shown in FIG. .

In this field sequential liquid crystal display device, since it is not necessary to provide a color filter in the liquid crystal display element, light is not absorbed by the color filter, and a plurality of unit colors are provided for all pixels of the liquid crystal display element. Since a color image is displayed by sequentially writing image data, a brighter and higher-definition liquid crystal display device is provided, compared with a liquid crystal display device in which color filters of a plurality of colors are alternately arranged corresponding to each pixel. A color image can be displayed.

[0007]

In the conventional field sequential liquid crystal display device, as shown in FIG. 3, a plurality of pixel rows of a liquid crystal display element are sequentially selected during a scanning period for each field and a plurality of pixels are arranged in each row. And writing light of a color corresponding to the written unit color image data from a light source using a retrace period after the scanning period. Therefore, in order to display a bright color image, the light emission time from the light source must be sufficiently long, or the luminance of the light source must be increased.

However, in order to sufficiently lengthen the light emission time from the light source, it is necessary to lengthen one field and lengthen the retrace period, which requires a lower frame frequency. Not only does the display flicker, but the number of display screens per unit time is reduced and the display quality of the moving image is reduced. In addition, increasing the luminance of the light source increases power consumption.

The present invention extends the light emission time from the light source without lowering the frame frequency, provides sufficient brightness, does not cause flickering in the display, and consumes low-quality moving images. It is an object of the present invention to provide a field-sequential liquid crystal display device capable of displaying with electric power.

[0010]

A field-sequential liquid crystal display device according to the present invention comprises a liquid crystal display element in which a plurality of pixels are arranged in a matrix in a screen area, and controls the transmission of light of these pixels to display. A plurality of pixel rows of the liquid crystal display element are sequentially arranged for each field for displaying one unit color of the plurality of unit colors in one frame for displaying an arbitrary color by mixing a plurality of unit colors. Display element driving means for selectively writing image data of one of the plurality of unit colors to the pixels of each row, and a predetermined number of screen areas of the liquid crystal display element behind the liquid crystal display element A plurality of light sources that are arranged corresponding to a plurality of divided areas divided for each pixel row, and sequentially emit light of the plurality of unit colors toward the corresponding divided areas, and the display element driving unit. Yo Corresponding to the sequential selection of a plurality of pixel rows of the liquid crystal display element, during a selection period in which each pixel row of each of the divided regions is selected, the light source corresponding to the divided region is turned off, and the Light source driving means for emitting light of a color corresponding to the unit color image data written in the selection period of the field from the light source corresponding to the divided region during a period other than the selection period. It is a feature.

That is, this field sequential liquid crystal display device sequentially selects a plurality of pixel rows of a liquid crystal display element, writes image data of one of the plurality of unit colors into the pixels of each row, and Each time the unit color image data is written to a predetermined number of pixel rows of the display element, the screen area of the liquid crystal display element is made to correspond to a plurality of divided areas divided for each of the predetermined number of pixel rows. Light of a color corresponding to the written unit color image data is emitted from a light source corresponding to the segmented area where writing of the image data has been completed among the plurality of arranged light sources. According to the field sequential liquid crystal display device, the emission time of light from the light source is extended without lowering the frame frequency, and the brightness is sufficient.
In addition, the display does not flicker and a high-quality moving image can be displayed with low power consumption.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The field sequential liquid crystal display device of the present invention, as described above, has a plurality of divisions in which a screen area of the liquid crystal display element is divided into a predetermined number of pixel rows behind the liquid crystal display element. A plurality of light sources that sequentially emit light of a plurality of unit colors are arranged corresponding to the respective regions, and a plurality of unit colors are mixed by the display element driving unit. , A plurality of pixel rows of the liquid crystal display element are sequentially selected for each field for displaying one unit color of the plurality of unit colors in one frame to be displayed, and the plurality of unit colors are assigned to pixels in each row. The image data of one of the unit colors is written, and the light source driving unit corresponds to the sequential selection of a plurality of pixel rows of the liquid crystal display element by the display element driving unit. During the selected selection period, the light source corresponding to the divided region is turned off, and during a period other than the selection period in the one field, writing is performed from the light source corresponding to the divided region during the selection period of the field. By emitting light of a color corresponding to the unit color image data, the emission time of the light from the light source is lengthened without lowering the frame frequency, the brightness is sufficient, and the display flickers. A moving image of good quality is displayed with low power consumption.

In the field sequential liquid crystal display device, the light source driving means may respectively control the plurality of light sources corresponding to the respective divided regions in a non-selection period other than the selection period of each pixel row in each of the divided regions of the subsequent field. It is preferable to include a unit that emits light of a color corresponding to the unit color image data written in the selection period of the previous field.

[0014] Further, the light source means may include a plurality of light sources corresponding to the respective divided areas, each of which has at least one of a selection period during which a pixel row of another divided area in one field is selected and a flyback period. It is more preferable to provide means for emitting light of a color corresponding to the field during the period of the unit.

In this field sequential liquid crystal display device, it is preferable that the light emission periods of the colors corresponding to the unit color image data from the plurality of light sources are set to the same length.

[0016]

1 and 2 show an embodiment of the present invention. FIG. 1 is an exploded perspective view of a field sequential liquid crystal display device.

In the field sequential liquid crystal display device of this embodiment, as shown in FIG. 1, a plurality of pixels (not shown) are arranged in a plurality of rows in a screen area 2, and the transmission of light of these pixels is controlled. , A display element driving means 6 for driving the liquid crystal display element 1, and a plurality of surface light sources 10a arranged on the rear side of the liquid crystal display element 1.
10b, 10c, 10d and the plurality of surface light sources 10a,
And a light source driving means 13 for driving 10b, 10c and 10d.

The liquid crystal display element 1 is an active matrix liquid crystal display element using a TFT (thin film transistor) as an active element. Although the internal structure is not shown, the liquid crystal display element 1 is provided with a frame-shaped sealing material 5 surrounding the screen area 2. A plurality of transparent pixel electrodes arranged in a matrix in a row direction and a column direction on one substrate, for example, on the inner surface of the rear substrate 4, of the pair of front and rear transparent substrates 3 and 4, and these pixel electrodes And the TF of each row
A plurality of gate lines for supplying gate signals to T and a plurality of data lines for supplying data signals to TFTs in each column are provided, and the plurality of pixel lines are opposed to the plurality of pixel electrodes on the inner surface of the other front substrate 3. A structure in which a single film-shaped transparent counter electrode that forms a plurality of pixels by regions is provided, and a liquid crystal layer is provided in a screen region 2 surrounded by the sealing material 5 between the pair of substrates 3 and 4. It has become.

The liquid crystal display element 1 is formed, for example, of a TN type in which liquid crystal molecules are twisted at a predetermined twist angle.
(Twisted nematic) type or STN (super twisted nematic) type liquid crystal display device, homogenous alignment type liquid crystal display device in which liquid crystal molecules are aligned homogeneously along one direction, or ferroelectric or antiferroelectric liquid crystal display device Although not shown in the drawing, polarizing plates are disposed on the outer surfaces of the pair of substrates 3 and 4, respectively.

The display element driving means 6 includes a scanning drive circuit 7 for supplying a gate signal to each of a plurality of gate lines of the liquid crystal display element 1 and a data signal for each of a plurality of data lines of the liquid crystal display element 1. And a control unit 9 for controlling the scanning drive circuit 7 and the write drive circuit 8 based on display information supplied from the outside, and for displaying an arbitrary color by mixed color. A plurality of pixel rows of the liquid crystal display element are sequentially selected during a scanning period for each field for displaying one unit color of a plurality of unit colors, for example, red, green, and blue unit colors. Image data of one of the red, green, and blue unit colors is written.

On the other hand, the plurality of surface light sources 10a, 10b,
Reference numerals 10c and 10d denote a plurality of divided areas 2a and 2 that divide the screen area 2 of the liquid crystal display element 1 into a predetermined number of pixel rows.
b, 2c, and 2d.

The number of pixel rows of the liquid crystal display element 1 is, for example, 220. In this embodiment, the screen area 2 of the liquid crystal display element 1 is divided into four areas 2 every 55 pixel rows.
a, 2b, 2c, 2d, and four surface light sources 10a, 10b, 10 corresponding to the four divided areas 2a, 2b, 2c, 2d, respectively, on the rear side of the liquid crystal display element 1.
c and 10d are arranged.

The surface light sources 10a, 10b, 10c, 10
d indicates the red, green, and blue unit colors of light sequentially, respectively, in the corresponding divided areas 2a, 2b, and 2 of the liquid crystal display element 1.
Light is emitted toward c and 2d.

These surface light sources 10a, 10b, 10c,
10d is each divided area 2a, 2 of the liquid crystal display element 1.
b, 2c, and 2d, the light guide plate 11 having one end face (the right end face in FIG. 1) as an incident end face and an entire front face as an exit face; A plurality of light-emitting elements 12R, 12G, and 12B that respectively emit red, green, and blue unit colors of light. The red, green, and blue light emitted from the light-emitting elements 12R, 12G, and 12B are provided. Light of each color is incident on the light guide plate 11 from its incident end face, and the light is emitted from the entire front surface of the light guide plate 11.

The light guide plate 11 has a front surface formed as a flat surface, and a rear surface formed on an inclined surface inclined from the incident end surface side to the opposite side to approach the front surface. (For example, an acrylic resin plate). Although not shown in the figure, the rear surface and both side surfaces of the light guide plate 11 and the end surface opposite to the incident end surface are formed by vapor deposition of aluminum or the like over the entire area. Alternatively, a reflection film made of a plating film is provided.

Further, a plurality of light emitting elements 12R, 12G, 12B arranged opposite to the incident end face of the light guide plate 11 are provided.
For example, a light emitting diode (hereinafter, referred to as a red LED) that emits red unit color light, a light emitting diode (hereinafter, referred to as green LED) that emits green unit color light, and a light emitting diode (hereinafter, referred to as green LED) that emits blue unit color light , Blue LED)
It is.

Although omitted in FIG. 1, the incident end face of the light guide plate 11 and the LEDs 12R, 12G, 12B
And between the LEDs 12R, 12G, and 12B, respectively, to diffuse the red, green, and blue emitted lights, respectively.
Is provided with a diffusion layer for allowing light to enter from almost the entire area of the incident end face.

In FIG. 1, LEDs 12R, 12R of three colors of red, green, and blue are opposed to the incident end face of the light guide plate 11.
G and 12B are arranged one by one.
LED 12 of three colors arranged opposite to the incident end face of
The number of R, 12G, and 12B may be plural.

The light source driving means 13 corresponds to the sequential selection of a plurality of pixel rows of the liquid crystal display element 1 by the display element driving means 6, and the plurality of divided areas 2a, 2b, During a period for selecting each of the pixel rows 2c and 2d (hereinafter, referred to as a selection period of a segmented region), the surface light source 10 corresponding to the segmented region 2a, 2b, 2c, 2d
a, 10b, 10c, and 10d are turned off, and light of a color corresponding to the unit color image data written in the selection period of the field is emitted during periods other than the selection period.

That is, the light source driving means 13 applies the plurality of surface light sources 10a, 10b, 10c, 10d corresponding to the respective divided areas 2a, 2b, 2c, 2d to the respective divided areas 2a, 2b, Means for emitting light of a color corresponding to the unit color image data written in the selection period of the previous field during a non-selection period other than the selection period of each of the pixel rows 2c and 2d; A plurality of surface light sources 10 corresponding to the regions 2a, 2b, 2c, 2d
a, 10b, 10c, and 10d, respectively, are written in the selection period of the previous field during the period between the selection period of the previous field and the selection period of the next field among the adjacent fields. Light of a color corresponding to the unit color image data is emitted.

Further, the light source driving means 13 connects the plurality of surface light sources 10a, 10b, 10c, 10d corresponding to the respective divided areas 2a, 2b, 2c, 2d to the respective divided areas in one field. Means are provided for emitting light of a color corresponding to the field during at least a part of a blanking period and another selection period in which a pixel row is selected.

FIG. 2 shows the plurality of surface light sources 10a, 10b,
FIG. 11 is a timing chart of light emission from 10c and 10d. Here, three unit color image data of red, green, and blue are sequentially written into pixels of a plurality of rows of the liquid crystal display element 1 in one frame, and the data are written in correspondence thereto. Surface light sources 10a, 10b, 10c, 1
An example is shown in which three colors of red, green and blue are sequentially emitted from 0d to display a full-color image.

In this field sequential liquid crystal display device, one frame for forming one color image is constituted by three continuous fields displaying images of different unit colors (red, green and blue). Each of these fields includes a scanning period for sequentially selecting all the pixel rows of the liquid crystal display element 1 and a blanking period after the scanning period.

First, the writing of image data of each unit color to the pixels of each row of the liquid crystal display element 1 will be described.
Writing of the image data of each unit color is performed by sequentially selecting a plurality of pixel rows of the liquid crystal display element 1 during the scanning period of the first field among three consecutive fields in one frame as shown in FIG. The red unit color image data is written into the pixels of each row, and the liquid crystal display element 1 is scanned during the scanning period of the second field.
Are sequentially selected, and green unit color image data is written into the pixels of each row. During the scanning period of the third field, the plurality of pixel rows of the liquid crystal display element 1 are sequentially selected and the pixels of each row are selected. This is performed by writing blue unit color image data.

In this embodiment, in order to obtain a flicker-free display, one frame is set to 20 msec, and each field is set to 6.6 msec. The scanning period (writing period of the unit color image data) of each field and the retrace period after the scanning period are, for example, scanning period = 4.4.
msec, retrace period = 2.2 msec. As described above, the number of pixel rows of the liquid crystal display element 1 is 220, and the number of pixel rows of each of the divided areas 2a, 2b, 2c, 2d is 55.
If it is a row, each of the divided areas 2a, 2b, 2c,
The selection period of each pixel row of 2d is 1.1 msec, and the selection period of pixels of each row of the divided regions 2a, 2b, 2c and 2d is 20 μsec.

On the other hand, the four surface light sources 10a, 10b, 10c and 10d corresponding to the four divided areas 2a, 2b, 2c and 2d of the liquid crystal display element 1 respectively have red, green, Emit blue light sequentially.

As shown in FIG. 2, each of the surface light sources 10a, 10a
b, 10c, and 10d denote light of a color corresponding to the unit color image data in the divided area 2 to which the surface light sources 10a, 10b, 10c, and 10d correspond during the scanning period in one field.
a non-selection period other than the selection period for selecting each of the pixel rows a, 2b, 2c, and 2d (hereinafter, referred to as a non-selection period of the divided region)
And light of a color corresponding to the unit color image data of at least a part of a flyback period after the scanning period in the one field is emitted.

Each of the divided areas 2a, 2b, 2c, 2d
The non-selection period in one field is a period after the selection period in the first divided area 2a including 1 to 55 pixel rows.
A second segmented region 2b consisting of 6 to 110 pixel rows;
Third partitioned area 2c composed of 111 to 165 pixel rows
Now, both periods before the selection period and after the selection period, 166-2
In the fourth divided area 2d composed of 20 pixel rows, this is a period before the selection period.

The surface light sources 10a, 10b, 10c, 10
It is preferable that the emission time of the light from the light source d is as long as possible in order to display a bright color image. However, the emission time of the light from the surface light sources 10a, 10b, 10c, and 10d depends on the surface light sources 10a, 10b, and 10d. When 10c and 10d overlap with the selection period (write period of the next selected unit color image data) of the next field of the corresponding segmented area 2a, 2b, 2c, 2d, a color shift occurs in the display color.

Therefore, in this embodiment, as shown in FIG. 2, the emission time of the light from the surface light sources 10a, 10b, 10c, and 10d is set to be equal to the surface light source 10a during the scanning period in one field. , 10b, 10c, 10d
During the non-selection period of the corresponding segmented area 2a, 2b, 2c, 2d, the blanking period (2.2 msec)
To 1 to 2 pixel row selection periods (20 to 40 μsec)
Is set to a length obtained by adding the time obtained by subtracting
The emission of light from a, 10b, 10c, and 10d is terminated before the selection period of the next field of the segmented regions 2a, 2b, 2c, and 2d corresponding to the surface light sources 10a, 10b, 10c, and 10d. ing.

Each surface light source 10a, 10b, 1 shown in FIG.
The emission timing of light from 0c and 10d will be described.
These surface light sources 10a, 10b, 10c, and 10d respectively correspond to the divided areas 2a, 2b, and 2 corresponding to the surface light sources.
During the selection period for each of the first to third fields c and 2d,
All three LEDs 12R, 12G, and 12B of three colors are stopped and turned off, and are turned off. During a period between the selection period of the previous field and the selection period of the next field, red, Green and blue LED12
LE of the color corresponding to the unit color image data written in the selection period of the previous field among R, 12G, and 12B.
D is driven to emit light of that color for the above-mentioned emission time.

That is, the first surface light source 1 corresponding to the first divided area (1 to 55 pixel rows) 2a of the liquid crystal display element 1
0a is the first divided area 2 for each of the first to third fields.
a, the red light is emitted from a period after the selection period of the first divisional region 2a of the first field to a period immediately before the selection period of the first divisional region 2a of the second field. Green light is emitted for a period immediately before the selection period of the first divisional region 2a of the third field from after the selection period of the first divisional region 2a, and in the next frame after the selection period of the first divisional region 2a of the third field. The blue light is emitted over a period immediately before the selection period of the first division region 2a of the first field.

The liquid crystal display element 1 has the second divided region (5
Second surface light source 1 corresponding to 6 to 110 pixel rows) 2b
0b is the second divided area 2 for each of the first to third fields.
b, the red light is emitted during a period immediately after the selection period of the second divisional region 2b of the first field and immediately before the selection period of the second divisional region 2b of the second field. Green light is emitted for a period immediately before the selection period of the second divisional region 2b of the third field from after the selection period of the two divisional region 2b, and in the next frame after the selection period of the second divisional region 2b of the third field. The blue light is emitted over a period immediately before the selection period of the second divided region 2b of the first field.

Further, the third surface light source 10c corresponding to the third section area (111 to 165 pixel rows) 2c of the liquid crystal display element 1 includes the third section area 2c for each of the first to third fields. Is turned off during the selection period of the third field of the first field.
Red light is emitted for a period immediately after the selection period of the segmented region 2c and immediately before the selection period of the third segmented region 2c of the second field, and after the selection period of the third segmented region 2c of the second field, the red light is emitted. Green light is emitted over a period immediately before the selection period of the three-partitioned region 2c, and immediately after the selection period of the third divisional region 2c of the third field and immediately before the selection period of the third divisional region 2c of the first field in the next frame. Blue light is emitted over the period.

Further, the fourth surface light source 10d corresponding to the fourth section area (166 to 220 pixel rows) 2d of the liquid crystal display element 1 is provided with a fourth section area for each of the first to third fields. The light is turned off during the selection period of 2d, and after the selection period of the fourth divisional region 2d of the first field, the fourth field of the second field starts.
Red light is emitted over a period immediately before the selection period of the segmented region 2d, and green light is emitted over a period immediately after the selection period of the fourth segmented region 2d of the second field and immediately before the selection period of the fourth segmented region 2d of the third field. And emits blue light after the selection period of the fourth divisional region 2d of the third field and immediately before the selection period of the fourth divisional region 2d of the first field in the next frame.

As described above, this field sequential liquid crystal display device sequentially selects a plurality of pixel rows of the liquid crystal display element 1 and writes image data of one of the plurality of unit colors into the pixels of each row. A plurality of divisions obtained by dividing the screen area 2 of the liquid crystal display element 1 into the predetermined number of pixel rows each time the unit color image data is written to the predetermined number of pixel rows of the liquid crystal display element 1 The areas 2a, 2b,
2c and 2d, respectively, from the surface light sources corresponding to the segmented regions where the writing of the image data has been completed among the plurality of surface light sources 10a, 10b, 10c and 10d, respectively, from the adjacent light source The light of the color corresponding to the unit color image data is emitted over a period between the field of the second field and the selection period of the divided area in the next field.

The field sequential liquid crystal display device sequentially selects a plurality of pixel rows of the liquid crystal display element 1 and writes image data of one of the plurality of unit colors into the pixels of each row while the image data of one of the plurality of unit colors is written. Light of a color corresponding to the unit color image data is sequentially emitted from a plurality of surface light sources 10a, 10b, 10c, and 10d respectively corresponding to the plurality of divided areas 2a, 2b, 2c, and 2d of the display element 1. Therefore, the emission time of the light from the surface light sources 10a, 10b, 10c, and 10d can be lengthened without lowering the frame frequency. Therefore, the emission luminance of the surface light sources 10a, 10b, 10c, and 10d can be reduced. There is no need to force it high.

Therefore, according to the field sequential liquid crystal display device, it is possible to display a high-quality moving image with low power consumption, with sufficient brightness, without causing flicker in the display.

Further, in the field sequential liquid crystal display device, a plurality of surface light sources 10 corresponding to the respective divided areas 2a, 2b, 2c, 2d are provided to the light source driving means 13.
a, 10b, 10c, and 10d are respectively assigned to the color corresponding to the unit color image data written in the selection period of the previous field during the non-selection period other than the selection period of each pixel row in each of the divided areas of the subsequent field. Since the light emitting means is provided, the light emitting time from the light source can be made sufficiently long without lowering the frame frequency.

Further, in the above embodiment, the light source means 1
3, a plurality of surface light sources 10a, 10b, 10c, and 10d corresponding to the respective divided areas 2a, 2b, 2c, and 2d are respectively selected by another selection in which each pixel row of another divided area in one field is selected. Since a means for emitting light of a color corresponding to the field is provided during at least a part of the period and the retrace period, the surface light sources 10a, 10b,
The emission time of light from 10c and 10d can be made longer, and a brighter display can be obtained.

That is, in the above embodiment, the emission time of the light of the color corresponding to the unit color image data from the plurality of surface light sources 10a, 10b, 10c, 10d is set to the above-mentioned time in the scanning period in one field. Surface light sources 10a, 10
b, 10c, 10d correspond to the divided areas 2a, 2b, 2
During almost the entire non-selection period of each of the pixel rows c and 2d,
The length is set to the sum of at least a part of the retrace period after the scanning period in the one field, and therefore, the emission time of the light from the surface light sources 10a, 10b, 10c, and 10d is increased. By making it longer, a brighter display can be obtained.

Further, in this embodiment, the light emission periods of the colors corresponding to the unit color image data from the plurality of surface light sources 10a, 10b, 10c and 10d are set to the same length. Plural divided areas 2 of liquid crystal display element 1
The brightness of the display of a, 2b, 2c, 2d can be made uniform, and a good quality color image without luminance unevenness can be displayed.

In the above embodiment, the screen area 2 of the liquid crystal display element 1 is divided into four divided areas 2a, 2b, 2c, 2d, and the divided areas 2a, 2b, 2c, 2d are respectively associated with the divided areas 2a, 2b, 2c, 2d. Sequentially emit light of a plurality of unit colors 4
Although the two surface light sources 10a, 10b, 10c, and 10d are arranged, the number of divisions of the screen area 2 of the liquid crystal display element 1 and the number of surface light sources may be any number as long as it is two or more.

Further, in the above embodiment, the liquid crystal display element 1
A light guide plate 11 having one end face as an incident end face and an entire front face as an emission face, and a light guide plate 11 opposed to the incident end face of the light guide plate 11 corresponding to the plurality of divided regions 2a, 2b, 2c, and 2d, respectively. The surface light sources 10a, 10b, 10c, and 10d each including a plurality of light-emitting elements 12R, 12G, and 12B respectively emitting red, green, and blue unit colors are disposed. Plural divided areas 2a, 2
The light sources arranged corresponding to b, 2c, and 2d, respectively,
If the device sequentially emits light of a plurality of unit colors toward the corresponding divided regions 2a, 2b, 2c, and 2d, for example, a plurality of light emitting elements that emit light of a plurality of unit colors are arranged in a row direction and a column direction. The corresponding divided areas 10a and 10 of the liquid crystal display element 1 are projected by an array surface light source or a projection system having a lens or the like that emits light from a plurality of light emitting elements that emit light of a plurality of unit colors.
Light emitted toward b, 10c, and 10d may be used.

[0055]

According to the field sequential liquid crystal display device of the present invention, the screen area of the liquid crystal display element is provided on the rear side of the liquid crystal display element so as to correspond to a plurality of divided areas each of which is divided into a predetermined number of pixel rows. A plurality of light sources that sequentially emit light of a plurality of unit colors are arranged toward the corresponding divided regions, and the display element driving unit displays an arbitrary color by mixing a plurality of unit colors. A plurality of pixel rows of the liquid crystal display element are sequentially selected for each field for displaying one unit color of the plurality of unit colors, and pixels of each row are provided with one of the unit colors of the plurality of unit colors. The image data is written, and the light source driving unit corresponds to the sequential selection of a plurality of pixel rows of the liquid crystal display element by the display element driving unit, during a selection period in which each pixel row of each of the divided regions is selected. The light source corresponding to the segmented area is turned off, and the unit color image data written during the selection period of the field from the light source corresponding to the segmented area during a period other than the selection period in the one field. Since the light of the color corresponding to the light is emitted, the emission time of the light from the light source is increased without lowering the frame frequency, the brightness is sufficient, and the display may flicker. And high quality moving images can be displayed with low power consumption.

In this field sequential liquid crystal display device, the light source driving means respectively controls the plurality of light sources corresponding to the respective divided regions during a non-selection period other than the selection period of each pixel row of each of the divided regions of the subsequent field. It is preferable that a means for emitting light of a color corresponding to the unit color image data written in the selection period of the previous field is provided. In this way, the light source can be emitted from the light source without lowering the frame frequency. Can be made sufficiently long.

Further, the light source means may control each of the plurality of light sources corresponding to each of the divided regions to at least one of a selection period during which each pixel row of another divided region in one field is selected and a flyback period. It is more preferable to provide a unit for emitting light of a color corresponding to the field during the period of the unit, whereby the emission time of the light from the light source is made longer and a brighter display is provided. Can be obtained.

In this field sequential liquid crystal display device, it is preferable that the light emission periods of the colors corresponding to the unit color image data from the plurality of light sources are set to the same length. Making the display brightness of the plurality of divided areas of the liquid crystal display element uniform,
A good quality color image without luminance unevenness can be displayed.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a field sequential liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a timing chart of light emission from a plurality of surface light sources in the field sequential liquid crystal display device.

FIG. 3 is a timing chart of light emission from a light source in a conventional field sequential liquid crystal display device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display element 2 ... Screen area | region 2a, 2b, 2c, 2d ... Division area 6 ... Display element drive means 7 ... Scan drive circuit 8 ... Writing drive circuit 9 ... Control part 10a, 10b, 10c, 10d ... Surface light source 11 ... Light guide plate 12R ... Red LED 12G ... Green LED 12B ... Blue LED 13 ... Light source driving means

Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat II (Reference) G09G 3/36 G09G 3/36 F-term (Reference) 2H093 NA28 NA43 NC43 ND08 ND17 ND39 NF05 NF13 NF17 NF20 5C006 AA22 AC02 AC25 AF42 AF69 AF71 AF73 BA12 BA13 BA19 BB11 EA01 FA23 FA25 FA47 5C080 AA10 BB05 CC03 DD05 DD06 DD26 DD30 EE28 FF07 JJ04 JJ06

Claims (4)

[Claims] 1. A liquid crystal display element in which a plurality of pixels are arranged in a matrix in a screen area, and controls the transmission of light of these pixels, and an arbitrary color is displayed by mixing a plurality of unit colors. One for
A plurality of pixel rows of the liquid crystal display element are sequentially selected for each field for displaying one of the plurality of unit colors in the frame, and one of the plurality of unit colors is assigned to a pixel of each row. Display element driving means for writing image data of two unit colors, and a rear side of the liquid crystal display element, corresponding to a plurality of divided areas obtained by dividing a screen area of the liquid crystal display element into a predetermined number of pixel rows. A plurality of light sources that are arranged and sequentially emit the light of the plurality of unit colors toward the corresponding divided areas, corresponding to the sequential selection of a plurality of pixel rows of the liquid crystal display element by the display element driving unit, In a selection period in which each pixel row of each of the divided regions is selected, the light source corresponding to the divided region is turned off, and during a period other than the selected period in the one field, the light source corresponding to the divided region is turned off. , Field sequential liquid crystal display device comprising the light source driving means for emitting light of a color corresponding to the written the unit color image data into a selected period of the serial field. 2. The light source driving means writes a plurality of light sources corresponding to each of the divided regions in a non-selection period other than a selection period of each pixel row in each of the divided regions of a subsequent field, and in a selection period of a previous field. 2. The field-sequential liquid crystal display device according to claim 1, further comprising means for emitting light of a color corresponding to the input unit color image data. 3. A light source driving unit according to claim 1, wherein each of the plurality of light sources corresponding to each of the divided areas is provided in at least a part of another selection period in which each pixel row of another divided area in one field is selected and a blanking period. 2. The field sequential liquid crystal display device according to claim 1, further comprising means for emitting light of a color corresponding to the field during the period. 4. The field according to claim 1, wherein emission times of light of colors corresponding to unit color image data from a plurality of light sources are set to the same length. Sequential liquid crystal display device.