JP3317553B2 - Field sequential color display - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a field sequential color display. More specifically, the present invention relates to a color filter for a field sequential color display capable of obtaining good color reproducibility even during high-speed driving, a method of driving the color filter, and a field sequential color display using the color filter About.

[0002]

2. Description of the Related Art As one of the multi-color displays using liquid crystal cells, a field sequential type color display has been conventionally known. As shown in FIG. 3, such a field sequential color display 1 generally has a monochrome CRT 2.
And the like, and a color filter 3 provided on the front surface thereof, and the color filter 3 includes a plurality of polarization filters 4a, 4b, and 4c having different transmission wavelength characteristics.
And liquid crystal cells 5a and 5b provided therebetween. For example, as the first polarizing filter 4a, a filter that transmits vertical polarization of red (R) and horizontal polarization of all colors of red (R), green (G), and blue (B) is provided. 4b is provided that transmits vertical polarization of all colors of R, G, and B and horizontal polarization of G, and transmits the vertical polarization of B and the horizontal polarization of all colors of R, G, and B as a third polarization filter 4c. What is to be provided. In addition, the liquid crystal cells 5a, 5
As b, a π cell is provided.

According to such a color filter 3, 2
One of the liquid crystal cells 5a and 5b is turned on or off as appropriate.
By setting the state, the color filter 3 is set to R, G,
It can be controlled so that either light of B or white light in which all of them are mixed is transmitted. For example, the liquid crystal cell 5a is
n, and the liquid crystal cell 5b is turned off. Of the white light emitted from the CRT 2, the first polarization filter 4a causes the vertical polarization of R and the horizontal polarization of all of R, G, and B to be turned on in the liquid crystal cell 5a. The incident light is transmitted through the liquid crystal cell 5a without rotating the polarization plane, and is incident on the second polarizing filter 4b. Then, the second polarization filter 4b is set to R
Only vertical polarized light and horizontal polarized light G are transmitted, and the light is incident on the liquid crystal cell 5b in the off state, and the polarization plane is 90 °.
The liquid crystal cell 4b is rotated to emit light, and the third polarizing filter 4
c. Then, only the R horizontal polarized light is emitted from the third polarizing filter 4c.

Therefore, in the multi-color display 1 using such a color filter 3, as shown in FIG.
The component images of each color B are switched and displayed. Also, a signal as shown in the figure is generated as a color switching signal Y for switching the transmitted light color of the color filter 3, and the transmitted light color of the color filter 3 is synchronized with the switching timing of the video signal X so that R, G, and B are changed. The switching is performed in a frame-sequential manner. For example, while the electron beam of the CRT 2 scans from one end to the other end of the R screen (i) according to the video signal X, the color filter 3 transmits only the R light, and the electron beam of the CRT 2 The color filter 3 transmits only the G light while scanning the G screen (ii), and the color filter 3 transmits only the B light while the electron beam scans the next B screen (iii). In the same manner, the color of the light passing through the color filter 3 is switched in the order of R, G, and B in synchronization with the scanning of one screen by the electron beam. Thereby, R, G,
Since the images of the color B are sequentially switched and emitted, a multicolor image is obtained due to the afterglow phenomenon in the retina of the human eye.

[0005]

However, in the conventional field sequential type color display 1, the electron beam of the CRT 2 scans the screen sequentially from the upper end to the lower end. When the electron beam is driven at a high speed, a sufficient afterglow time cannot be ensured below the screen of the color display 1 because the entire surface is switched immediately when the upper edge of the screen is reached. Therefore, the original color cannot be reproduced. There was a problem. For example, at a certain time t1, the color filter 3 transmits R light, and the CRT 2
The electron beam scans the lower end of the screen and the color display 1 at the scanned portion starts emitting R light, but at the next time t2, the electron beam reaches the upper end of the screen and the color filter 3
When the transmitted light is completely switched to G light, the lower end of the color display 1 that has just started emitting R light is also switched to emit G light, so that the afterglow time of R light is sufficiently ensured. The original color cannot be reproduced in the image.

An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a field sequential color display capable of obtaining good color reproducibility even at high speed driving. Aim.

[0007]

According to the present invention, the above object is achieved by dividing a color filter in the vertical direction and sequentially shifting the switching timing of R, G, B between the divided areas. It has been found that a sufficient afterglow time can be secured in any of the divided areas, and the present invention has been completed.

That is, the present invention provides at least a first color,
White for switching and displaying the component images of the second color and the third color
Black image display apparatus, that Do a liquid crystal cell provided between the transmission wavelength characteristics different polarization filters each polarizing filter
Color filters, and component image in black and white image display device
Transmitted light color of color filter according to image switching timing
Equipped with a color switching signal circuit that generates a color switching signal
Field sequential type color display <br/> Oite, each liquid crystal cell in the vertical direction of the display screen
Is divided into independently drivable plurality of zones, independently can be transmitted a predetermined color of light in each area of the color filters corresponding to the respective liquid crystal cell is split, transmitted light color
The color switching signal for switching
A field system that is sequentially shifted between areas
Provide a sequential color display .

Also, such a field sequencer
At least as a driving method for
Also switch the component image of the first color, the second color and the third color
Black and white image display device,
Liquid crystal provided between a number of polarizing filters and each polarizing filter
For color filters composed of cells and monochrome image display devices
Color fill according to the switching timing of component images
Color switching signal that generates a color switching signal that switches the transmitted light color of the
Field sequential color data
In the display driving method, the color filter
LCD cells are independent of each other in the vertical direction of the display screen.
Divided into a plurality of sections that can be driven
Independent in each area of the color filter corresponding to the crystal cell
Use a material that can transmit light of the specified color
Then, in each area of the color filter divided in the vertical direction of the screen, at least the first color light, the second color light, and the third color light are sequentially switched and transmitted, and the transmitted light color < A method is provided for turning each liquid crystal cell on and off so that the switching timing of each of the liquid crystal cells is sequentially shifted between adjacent sections of the color filter.

[0010]

[0011]

In the color filter of the present invention, the liquid crystal cell is divided in the vertical direction of the display screen, and each liquid crystal cell is formed of an independently drivable area. This color filter is used for a field sequential type color display. Used in accordance with the driving method of the color filter of the present invention, and in this case, the transmitted light color of each area of the color filter is switched according to the switching timing of the component image of each color of the monochrome image display device. Then, at least the first color (for example, R) light, the second color (for example, G) light, and the third color (for example, light) are obtained from each area of the color filter divided in the vertical direction on the screen of the color display. B) are sequentially switched and emitted, and the switching timing of each color light between each area of the adjacent color filter is set to a black and white image table. While switching timing of each color component image of the device and have a fixed relationship, so successively shifted.
For example, at some point the CRT electron beam begins to scan the bottom area of the display screen, the color filters in that area become transparent to R light, and at the next time the electron beam scans the top area of the display screen. First, even if the color filter in the upper end area is switched to transmit G light, the transmitted light of the color filter in the lower end area is not switched to the G light at the same time as the color filter in the upper end area, and the electron beam The R light can be used until the scanning of the lower end area is started. Therefore, even if the electron beam is driven at a high speed, it is possible to secure a sufficient afterglow time for each color in any part of the screen, and it is possible to reproduce a desired color in an image.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings.

FIG. 2 is an explanatory diagram of the color display 11 according to the embodiment of the present invention. In the color display 11 of this embodiment, the monochromatic CRT 2 and the polarization filters 4a, 4b and 4c of the color filter 13 are constituted by the same ones as in the conventional example shown in FIG. , 5b are each divided into four sections 5a-1 to 5a-4, 5b-1 to 5b-4 which can be independently driven in the vertical direction of the display screen. As shown in FIG. 1, it is composed of four sections 13-1 to 13-4. Also,
A color switching signal generating circuit for generating color switching signals Y-1, Y-2, Y-3, Y-4 for switching the transmitted light colors of the respective areas 13-1 to 13-4 of the color filter; (Not shown).

The divided liquid crystal cells 5a, 5b
Are formed, for example, in the unit liquid crystal cells 5a-1 to 5a-5.
a-4, 5b-1 to 5b-4 may be separately formed and arranged in the vertical direction.
The transparent electrode b may be formed from four portions each of which can be independently turned on and off.

In this embodiment, the liquid crystal cell is divided into four sections in the vertical direction, but the number of divisions of the liquid crystal cell is not limited to this. By increasing the number of divisions, it is possible to further cope with high-speed driving of the electron beam. However, when the number of divisions is too large, a plurality of areas of the color filter 13 corresponding to the finely divided liquid crystal cells enter the field of view at the same time, and the boundary of the areas having different color tones can be seen on one screen, which is not preferable. . Therefore, for example, when the scanning speed of the electron beam is to be about three times the conventional speed, it is usually preferable that the number of divisions is 5 or less.

The color display 11 operates as shown in FIG. That is, the CRT 2 switches and displays the R, G, and B component images in a frame-sequential manner by the video signal X, similarly to the conventional example shown in FIG. At this time, the color switching signals Y-1, Y-2, Y-3, and Y-4 are respectively input to the color filters 13-1 to 13-4 in each area as shown in FIG. One area 13-1 of the filter is
The transmitted light color is switched in synchronization with the switching timing of the component image in the video signal X, and the transmitted light color switching timing is sequentially changed between the adjacent sections 13-1 to 13-4 including this section 13-1. It will shift. For example, at a certain time t1, the electron beam is moved below the R screen (i) (the lower end area 1 of the color filter).
3-4), the entire area of the color filter 13-1 to 13-4
R light is emitted from the G screen at the next time point t2.
When the color filter 13 reaches the upper end of (ii) (the upper end area 13-1 of the color filter), the color light of the color filter 13 is switched only in the upper end area 13-1, and the G light is emitted from the upper end area 13-1. Then, when the electron beam reaches the area 13-2 of the next color filter, the transmitted light color is switched only in the area 13-2, and the G light is emitted from the area 13-2. When the electron beam reaches the next area 13-3,
The transmitted light color is switched only in the area 13-3, and the G light is emitted from the area 13-3. When the electron beam finally reaches the lower area 13-4, only the lower area 13-4 is emitted. The transmitted light color is switched so that the G light is emitted from this area 13-4. Hereinafter, similarly, the transmitted light color of each area of the color filter is sequentially switched to R, G, and B.

Thus, for example, at a certain time t1, the electron beam starts scanning the lower end area 13-4 of the color filter,
At the next time point t2, the electron beam reaches the upper end area 13-1 of the color filter, and the G light is emitted from the upper end area 13-1. Thus, the R light is still emitted from the lower end area 13-4 of the color filter. The R light from the lower end area 13-4 switches to the G light when the electron beam next starts scanning the lower end area 13-4 of the color filter. Therefore, a sufficient afterglow time is secured in the lower end area 13-4, and the original color can be reproduced in the image.

In the above embodiment, the case where the light of each color of R, G, and B is sequentially switched and emitted in each section of the color filter has been described.
A blanking of white, which emits all the colors of B, or black, which does not emit any of R, G, and B, may be provided. This makes it possible to improve the contrast of the screen.

[0019]

When the color filter of the present invention is used in a field sequential type color display, it is possible to obtain good color reproducibility in an image even when an electron beam of a CRT is driven at a high speed.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an operation of a field sequential color display according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a field sequential type color display according to an embodiment of the present invention.

FIG. 3 is a configuration diagram of a conventional field sequential color display.

FIG. 4 is an explanatory diagram of an operation of a conventional field sequential color display.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Conventional field sequential type color display 2 Monochrome CRT 3 Conventional color filter 4a, 4b, 4c Polarizing filter 5a, 5b Liquid crystal cell 5a-1-5a-4, 5b-1-5b-4 Liquid crystal cell 11 Field of Example Sequential system color display 13 Color filter of embodiment 13-1, 13-2, 13-3, 13-4 Each area of color filter of embodiment X video signal Y, Y-1, Y-2, Y-3, Y-4 color switching signal

Claims (2)

(57) [Claims] At least a first color, a second color and a third color.
Monochrome image display apparatus, Luca color filter of a liquid crystal cell transmission wavelength characteristic is provided between a plurality of different polarizing filter and the polarizing filter to display by switching the color component image,
And switching of component images in black and white image display device
Color switching to switch the color of the transmitted light of the color filter according to the color
A field switch equipped with a color switching signal circuit that generates a signal
In a sequential color display , the liquid crystal cells are independent of each other in the vertical direction of the display screen.
Is divided into drivable plurality of zones, each zone of the color filters corresponding to the respective liquid crystal cells which are divided independently can be transmitted a predetermined color of light, color switching signal for switching the transmitted light color, Next to the color filter
Fields that are input so that they are sequentially shifted
A color sequential color display. 2. The method of claim 1, wherein the first color, the second color, and the third color
Black-and-white image display device that switches and displays component images of different colors, a plurality of polarizing filters with different transmission wavelength characteristics, and each polarizing filter.
Color filters consisting of liquid crystal cells provided between
And switching of component images in black and white image display device
Color switching to switch the color of the transmitted light of the color filter according to the color
A field switch equipped with a color switching signal circuit that generates a signal
The driving method of the kenshall color display
The liquid crystal cell is used as a color filter on the display screen.
Divided into multiple areas that can be driven independently in the vertical direction
Color filters corresponding to each divided liquid crystal cell.
In each area, light of a predetermined color can be transmitted independently.
And using at least the first color light, the second color light, and the third color light in each area of the color filter divided in the vertical direction of the screen by sequentially switching the light, and switching timing of the transmitted light color, so as to sequentially shift between each section of the adjacent color filters, on the respective liquid crystal cells - off feature
Method of driving a field sequential type color display.