JP2000171799A - Device and method for liquid crystal display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device in which a color filter is eliminated from a conventional liquid crystal display device to reduce the cost of the parts and the efficiency of the light utilization is greatly improved and to provide a liquid crystal display method. SOLUTION: A red color light source 1a, a green color light source 1b and a blue color light source 1c are not simultaneously lighted, rather, they are independently and cyclically lighted in the order of red to green to blue, for example. Red color light beams emitted from the light source 1a, which is turned on for 1/180 of a second, repeat reflection inside a light transmission plate 2, and are emitted from the top surface of the plate 2 as uniform red color light beams. Only the light beams having polarized in a certain direction by a polarization plate 3a are selected, pass a glass substrate 4a and made incident on a liquid crystal section 7. The red color light beams passed the section 7, pass red pixels 5R provided between a black matrix 6, emitted through a glass substrate 4b and a polarization plate 3b and display a red color picture on an optical emitting surface. Similarly, green and blue color light beams are emitted to display a picture.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a liquid crystal display device and a liquid crystal display method, and more particularly, to display an image on a light emitting surface by controlling transmission of light incident from a light incident surface using a liquid crystal. The present invention relates to a liquid crystal display device and a liquid crystal display method.

[0002]

2. Description of the Related Art Conventionally, as this type of liquid crystal display device, p.171 of “Amorphous” (Kodansha) edited by Yukinori Kuwano.
~ P.172 for details, such as LCD TVs and PCs
It has already been commercialized as a monitor.

FIG. 1 is a partial sectional view of a conventional liquid crystal display device.

In FIG. 1, 1 is a light source, 2 is a light guide plate, 8
Denotes a liquid crystal panel. Further, the liquid crystal panel 8 includes the polarizing plate 3.
a and 3b, glass substrates 4a and 4b, a color filter 5, a black matrix 6, and a liquid crystal unit 7. Liquid crystal molecules are sealed in the liquid crystal unit 7, and TFT elements and electrodes necessary for controlling the transmission / non-transmission of light by changing the twist direction of the liquid crystal molecules by 90 degrees are provided. .

[0005] The white light emitted from the light source 1 is
And the light is repeatedly reflected inside and emitted from the upper surface of the light guide plate 2. As for the light emitted from the light guide plate 2, only light having polarization in a certain direction is selected by the polarizing plate 3 a, passes through the glass substrate 4 a, and enters the liquid crystal unit 7.
The light modulated by the liquid crystal unit 7 is converted by the red pixel 5R, the green pixel 5G, and the blue pixel 5B of the color filter 5 into light of each of the three primary colors, and the light of the black matrix 6 for separating the pixels is separated. The light passes through the gap, is emitted through the glass substrate 4b and the polarizing plate 3b, and is
An image is displayed on the light emitting surface of the.

FIG. 2 is a timing chart of a control signal for causing one pixel unit composed of three pixels of red, green and blue to emit light. However, the control signal includes a luminance signal, which is not directly related to the present invention, and therefore, the description thereof is omitted.

When the light source 1 is turned on at time T1, white light is emitted. However, since all pixels are opaque until time T2, this pixel unit is black. Next,
From time T2 to time T3, only the red pixel becomes transparent, and this pixel unit changes to red. Also, from time T3 to time T
At 4, only the green pixel becomes transparent, this pixel unit changes to green, and from the last time T4 to time T5, only the blue pixel becomes transparent, this pixel unit changes to blue, and then becomes black again.

For example, in the case of the NTSC interlace system, this control signal is received as TV radio waves, and the video signal is 60 frames per second. Therefore, at time T2, this pixel unit changes to red for 1/60 second. Then, at time T3, which is 1/60 second after time T2, the color changes to green for 1/60 second, and at time T4, which is 1/60 second after time T3, the color changes to green.
The state of a control signal for changing the color to blue for one second is shown.

[0009]

Since the conventional liquid crystal display device is configured as described above, the light source 1 is always in the ON state, and the white light incident from the light guide plate 2 is
The polarizers 3a and 3b that align the polarized light lose 1/2 and the color filter 5 that separates the color loses 2/3. As a result, only 1/6 of the entire incident light is used for display. .

The loss due to the color separation is caused by the fact that the color filter 5 transmits only one color light of red, green and blue, absorbs the light of the other color and converts it into heat or the like. When white light, in which various colors are completely mixed, is incident on the color filter 5, two-thirds of three colors are lost. As a result, the display screen itself of the liquid crystal display device does not become bright or requires a large amount of power to eliminate it, so that heat proportional to the power consumption is generated, and portable products such as notebook PCs are used. When using a liquid crystal display device, there is a problem that the battery is quickly consumed and the usable time is shortened.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is possible to reduce the cost of parts by removing a color filter from a conventional liquid crystal display device and to significantly improve the light use efficiency. Accordingly, it is an object to provide a liquid crystal display device and a liquid crystal display method which reduce power consumption and are suitable for portable products.

[0012]

According to a first aspect of the present invention, there is provided a liquid crystal display device according to the first aspect of the present invention, in which a liquid crystal is used to control the transmission of light incident from a light incident surface to emit light. A liquid crystal display device that displays an image on a surface, wherein the light source independently and cyclically enters at least three or more colors of light on the light incident surface, and in synchronization with each of the light incident from the light source. Light transmission control means for controlling the transmission of light by changing the state of the liquid crystal.

According to a second aspect of the present invention, there is provided a liquid crystal display device comprising:
The liquid crystal display device according to claim 1, wherein the light source is:
It emits light of the color described in a) or b) below.

A) red, green and blue b) yellow, magenta and cyan The liquid crystal display method according to the third aspect of the present invention provides a light emitting surface by controlling transmission of light incident from a light incident surface using a liquid crystal. A liquid crystal display method for displaying an image on the light incident surface, wherein a first step of independently and cyclically incident light of at least three or more colors on the light incident surface; and synchronizing with each of the light incident from the light source. And controlling the transmission of light by changing the state of the liquid crystal.

According to a fourth aspect of the present invention, there is provided a liquid crystal display method comprising:
The liquid crystal display method according to the third aspect is characterized by including a third step of emitting light of the color described in the following a) or b).

A) red, green and blue b) yellow, magenta and cyan

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the following terms are defined.

The "light of at least three or more colors" described in the claims generally means "red, green and blue" colors which are three primary colors required to reproduce all colors. Although it is light, it may be a “yellow, magenta, and cyan” color that is in a complementary relationship between them. However, the combination and the number of these colors are not limited. For example, in the recent film industry, four colors of “red, green, blue and purple” are reproduced more vividly, and thus these four colors are reproduced. A combination of colors may be used, or a combination of colors that are unrelated to the three primary colors of “orange, yellow and indigo” depending on the application.

The expression "independently and cyclically entering light of three or more colors" means, for example, controlling a light source that independently emits red, green and blue, which are the three primary colors, to red → green →
It means that light enters in the order of blue → red → green → blue →.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It is assumed that light emitted from a light source is three primary colors, red, green and blue.

FIG. 3 is a partial cross-sectional view of the liquid crystal display device according to the present invention. The same components as those described with reference to FIG. 1 are denoted by the same reference numerals and description thereof is omitted. In particular, the difference from the conventional liquid crystal display device of FIG. 1 is that a light source and a color filter described below are removed.

Reference numerals 1a, 1b and 1c denote a red light source 1a, a green light source 1b and a blue light source 1c each composed of an LED or a cold cathode tube which independently emits one of the three primary colors. The amount of current is individually controlled.

The red light source 1a, the green light source 1b and the blue light source 1c do not light up at the same time, but emit light independently and cyclically in the order of red → green → blue → red → green → blue →. As described above, in the case of the NTSC interlace system, the video signal is 60 frames per second,
Red → green → blue light emission is repeated with 1/60 second as one cycle (that is, each light source repeats light emission for 180th of a second by shifting the timing).

First, the red light emitted when the red light source 1a is turned ON for 1/180 second is repeatedly reflected inside the light guide plate 2, and is emitted as uniform red light from the upper surface thereof. Only light having a polarized light in a certain direction is selected by 3a, passes through the glass substrate 4a, and enters the liquid crystal unit 7. The red light modulated so as to be transmitted by the liquid crystal unit 7 passes through the red pixel 5R arranged between the black matrices 6 separating the pixels, and is emitted through the glass substrate 4b and the polarizing plate 3b. Panel 8
A red image is displayed on the light exit surface of the. However, when modulated to be opaque, red light is not emitted from the light exit surface.

Next, after the red light source 1a is turned off, the green light emitted when the green light source 1b is turned on for 1/180 second is emitted in the same manner as the above-described red light. And a green image is displayed on the light emitting surface of the liquid crystal panel 8.

Finally, after the green light source 1b is turned off, the blue light source 1c is turned on for 1/180 second.
Similarly, the blue light emitted in the state becomes the blue pixel 5B.
And a blue image is displayed on the light-emitting surface of the liquid crystal panel 8 to generate a time difference of 1/180 second, thereby forming a red image, a green image, and a blue image.
One image is formed for 1/60 second, and this is defined as one cycle, and image display is repeated 60 times per second.

FIG. 4 is a view showing the red and red portions of the liquid crystal display device according to the present invention.
6 is a timing chart of a control signal for causing one pixel unit composed of three pixels of green and blue to emit light.

Taking the case of the NTSC interlace system as an example, the red light source 1a, the green light source 1b, and the blue light source 1
c emits light for 1/180 second only once every 1/60 second with a time difference of 1/180 second. Also,
The control signal for causing the three pixels of red, green, and blue to emit light shown in this figure is the control signal shown in FIG.
It is created by taking the product (AND) with the signal for OFF control.

The red light source 1a, the green light source 1b, and the blue light source 1c are in the ON state between the times T1 and T2, but each pixel is black because all the pixels are in the non-transmissive state.

Next, when the red light source 1a is ON from time T2 to time T3, the red pixel control signal is transparent and the other two colors are non-transparent, so that this pixel unit changes to red. From time T3 to time T4, only the green pixel becomes transparent, this pixel unit changes to red, and from the last time T4 to time T5, only the blue pixel becomes transparent,
This pixel unit changes to blue.

That is, FIG.
Changes the pixel unit to red for 1/180 second, and from time T3 (1/60 second after T2) to time T4
Changes the pixel unit to green for 1/180 second, and from time T4 (2/60 seconds after T2) to time T5
Shows the state of the control signal for changing the pixel unit to blue for 1/180 second. Although the time for which each pixel emits light is one third of the conventional time, the light emission intensity is sufficiently maintained because the light is not attenuated by the color filter.

FIG. 5 is a flowchart showing a pixel light emission processing routine in the liquid crystal display method according to the present invention.

When the power of the device itself is turned on, the pixel light emission control unit (not shown) of the liquid crystal display device is turned on in step 20.
At 0, the three primary colors of light are emitted independently and cyclically, and the process proceeds to step 201.

The pixel emission control unit determines in step 201 whether the red light source is ON and the blue pixel control signal is transparent. If NO, the process proceeds to step 203. On the other hand, if YES, the process proceeds to step 203. For example, in step 202, the red pixel is caused to emit light, and the process proceeds to step 203.

The pixel emission control unit determines in step 203 whether the green light source is ON and the green pixel control signal is transparent. If NO, the process proceeds to step 205. On the other hand, if YES, the process proceeds to step 205. For example, in step 204, the green pixel is made to emit light, and the process proceeds to step 205.

The pixel emission control unit determines in step 205 whether the blue light source is ON and the blue pixel control signal is transparent. If NO, the process proceeds to step 201. On the other hand, if YES, the process proceeds to step 201. For example, in step 206, the blue pixel is caused to emit light, and the process proceeds to step 201 to repeat this processing.

[0037]

As described above, according to the liquid crystal display device and the liquid crystal display method of the present invention, the three primary color lights are emitted independently and cyclically, and the state of the liquid crystal is changed in synchronization with each light. By controlling the transmission of light, the color filter can be removed from the conventional liquid crystal display device, and as a result, the cost of parts can be reduced.

Further, since the color filter is eliminated, the light use efficiency can be remarkably improved, and the power consumption can be reduced.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a conventional liquid crystal display device.

FIG. 2 is a timing chart of a control signal for causing one pixel unit of a conventional liquid crystal display device to emit light.

FIG. 3 is a partial cross-sectional view of the liquid crystal display device according to the present invention.

FIG. 4 is a timing chart of a control signal for causing one pixel unit of the liquid crystal display device according to the present invention to emit light.

FIG. 5 is a flowchart showing a pixel light emission processing routine in the liquid crystal display method according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 light source 1a red light source 1b green light source 1c blue light source 2 light guide plate 3a polarizing plate 3b polarizing plate 4a glass substrate 4b glass substrate 5 color filter 5R red pixel 5G green pixel 5B blue pixel 6 black matrix 7 liquid crystal unit 8 liquid crystal panel

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kenkichi Okamoto 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Michiaki Sato 2-chome, Keihanhondori, Moriguchi-shi, Osaka No. 5 Sanyo Electric Co., Ltd. (72) Yoshiaki Yamada 2-5-5 Keihan Hondori, Moriguchi-shi, Osaka 2-5 Sanyo Electric Co., Ltd. (72) Kenji Kiyota 2 Keihan-hondori, Moriguchi-shi, Osaka 5-5-5 Sanyo Electric Co., Ltd. F term (reference) 2H091 FA23Z FA35Z FA41Z FD06 FD12 GA11 LA15 LA30 2H093 NA65 NC31 NC43 ND17 ND39 ND54 NE06 NH15

Claims (4)

[Claims] 1. A liquid crystal display device for displaying an image on a light exit surface by controlling transmission of light incident from a light incident surface using a liquid crystal, wherein light of at least three or more colors is provided on the light incident surface. And a light transmission control unit that controls the transmission of light by changing the state of the liquid crystal in synchronization with each of the light incident from the light source. Liquid crystal display device. 2. The liquid crystal display device according to claim 1, wherein the light source emits light having a color described in a) or b) below. a) red, green and blue b) yellow, magenta and cyan 3. A liquid crystal display method for displaying an image on a light exit surface by controlling transmission of light incident from a light incident surface using a liquid crystal, wherein light of at least three colors is provided on the light incident surface. And a second step of controlling the transmission of light by changing the state of the liquid crystal in synchronization with each of the light incident from the light source. Liquid crystal display method. 4. The liquid crystal display method according to claim 3, further comprising: a third step of emitting light of a color described in a) or b) below. a) red, green and blue b) yellow, magenta and cyan