JPH05224155A - Projection type liquid crystal display device - Google Patents

Abstract

PURPOSE:To eliminate the need of a gradation correction circuit which is more complicated as it becomes highly accurate by rotating the polarizing axis of a polarizing plate separately installed besides the polarizing plate of a liquid crystal panel and adjusting the quantity of light. CONSTITUTION:As to the projection type display device provided with the liquid crystal panel 5 using the polarizing plate 4 as a light valve, the light quantity is adjusted by rotating the polarizing axis of the polarizing plate 3 separately installed besides the polarizing plate 4 of the liquid crystal panel 5. In such a case, it is possible to have such a constitution that the liquid crystal panel used as a light controlling filter 7 is installed instead of the polarizing plate 3. Thus, a linearly polarized light is obtained by making a light beam irradiated from a light source 1 through a collimator lens 2 transmit through a polarizing plate 3 for adjusting light quantity, and the quantity of transmitted light is adjusted by rotating a polarization direction. Meanwhile, the rotation angle of the electrically transmitted light is adjusted by using the light controlling liquid crystal filter 7, and the quantity of the light irradiated to the liquid crystal panel 5 is easily adjusted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection display device. In particular, the present invention relates to a projection type liquid crystal display device that transmits light to a liquid crystal panel to perform enlarged projection.

[0002]

2. Description of the Related Art In a color projection display device using a liquid crystal panel, generally, three liquid crystal panels corresponding to RGB are used, and they are combined to form an image. The configuration of a typical device is shown in FIGS. 23, 24 and 25. Figure 23
In the figure, 301 is a light source, 308-1 and 308-2 are dichroic mirrors, 308-3 is color separation means by a dichroic mirror or a total reflection mirror, 302 is a collimator lens, 304 is a polarizing plate, 305 is a liquid crystal panel, and 306 is projection. It is a lens, and in FIGS. 24 and 25, similar parts are denoted by corresponding numbers. However, reference numeral 329 in FIG. 25 indicates a dichroic prism.
The operation will be described with reference to the example of FIG.

First, the light emitted from the light source 301 is separated by the color separation means for each light of RGB colors, and is condensed by the collimator lens 302. After that, polarizing plate 3
The linearly polarized light component is extracted by 04, and the liquid crystal panel 30
After the video information is written by 5, the projection lens 30
6 and is synthesized on the screen. Figure 2
4, the same applies to the example of FIG. 25, but in the example of FIG. 23, RGB images are separately projected and combined on the screen, whereas in FIGS. Different.

In the display device having such a configuration, the combined light rays are white in the pixels in which each liquid crystal panel is turned on (transmitted). However, the color of the pixel in this case is determined by the output ratio of the light rays that pass through the RGB liquid crystal panel, and it is necessary to consider the light source used, the color separation means, and the wavelength dependence of the transmittance of the liquid crystal panel. Since the wavelength dependence of the transmittance of the light source, the color separation means, and the liquid crystal panel varies, in order to obtain the desired color, the light output from the light source is divided into RGB by the separation means, and then each light is separated. The output needs to be corrected. In the conventional device, a method combining the following three methods has been used.

(1) The output is corrected for each color. The width of the wavelength separated by the color separation means is adjusted, or an ND filter is inserted after the color separation means for correction. (2) The correction is performed by changing the signal applied to each liquid crystal panel to change the transmittance when the liquid crystal panel is in the ON state. (3) The problem of (1) is solved by the method of (2). In other words, after the RGB ratio is corrected to a standard ratio by the color separation means or the filter, the transmittance is changed according to the change with time of the light source, the user's preference, the change of viewing environment, etc. by the signal applied to the liquid crystal panel. Let

[0006]

However, these methods have the following problems. According to the method (1), since the correction rate of the light intensity in each panel is fixed, it is not possible to cope with changes over time in the light source, user preferences, changes in the viewing environment, and the like. In the method of (2), it is necessary to facilitate the gradation for light control on the liquid crystal panel. For this reason, the number of gradations that can be used for image display is reduced compared to the gradation that the liquid crystal panel originally has.

The method (3) still has the same problem as the method (2) although the degree is small. INDUSTRIAL APPLICABILITY The present invention is a projection-type liquid crystal display device capable of adjusting color tone and dimming without reducing the gradation of a liquid crystal panel, and also capable of adjusting due to changes in the light source over time, user preference, changes in viewing environment, and the like. The purpose is to provide.

[0008]

FIG. 1 shows the basic principle of the present invention. In a projection display device having a liquid crystal panel using a polarizing plate as a light valve, the present invention provides:
It is characterized in that the amount of light is adjusted by rotating the polarization axis of a polarizing plate 3 installed separately from the polarizing plate 4 of the liquid crystal panel 5. In addition, as shown in FIG.
It is also possible to adopt a configuration in which a liquid crystal panel for use as a light control filter is provided.

[0009]

According to the present invention, the light beam emitted from the light source through the collimator lens is transmitted through the light amount adjusting polarizing plate to be linearly polarized light, and the light amount to be transmitted can be adjusted by rotating the polarization direction. On the other hand, when the liquid crystal filter for dimming is used, the optical rotation angle of the electrically transmitted light can be adjusted, so that the amount of light applied to the liquid crystal panel can be easily adjusted.

[0010]

【Example】

[Embodiment 1] FIG. 3 is a block diagram of Embodiment 1 according to the present invention. In FIG. 3, the projection type liquid crystal display device includes a light source 11,
Dichroic mirror or total reflection mirror 18-1, 18
Reference numerals -2 and 18-3, a collimator lens 12, a dimming polarizing plate 13, a polarizing plate 14, a liquid crystal panel 15, and a projection lens 16.

The operation will be described with reference to FIG. The light output from the light source 11 is dichroic mirrors 18-1, 18
Color separation is performed for each color by -2 and 18-3, and the light is condensed by the collimator lens 12. After that, the intensity of light incident on the liquid crystal panel 15 is adjusted by the inclination of the polarization axes of the light control polarizing plate 13 and the polarizing plate 14 near the liquid crystal panel. After that, image information is written by the liquid crystal panel 15 and visualized by the polarizing plate 14, and then the projection lens 1
6 is projected. Light control polarizing plate 13 and polarizing plate 14
In the initial state, it is possible to adjust the color balance of the image by arranging the polarization axes so that they are parallel to each other and rotating them independently for each RGB system.

Further, the brightness of the image can be adjusted by simultaneously rotating the dimming polarizing plate 13 in each of the RGB systems by the same angle. [Embodiment 2] Embodiment 1 shown in FIG. 3 is an example in which RGB images are combined on a screen, but FIG. 4 shows Embodiment 2 in the case where projection is performed after the combination. In FIG. 4, the projection type liquid crystal display device includes a light source 21, a dichroic mirror or total reflection mirrors 28-1, 28-2, 28-.
3, 28-4, 28-5, 28-6, collimator lens 22, dimming polarizing plate 23, polarizing plate 24, liquid crystal panel 2
5 and the projection lens 26.

The operation will be described with reference to FIG. The light output from the light source 21 is color-separated by the dichroic mirror 28-1, and each light is reflected by the liquid crystal panel 2 due to the inclination of the polarization axis between the dimming polarizing plate 23 and the polarizing plate 24 near the liquid crystal panel.
The intensity incident on 5 is adjusted. After this, the liquid crystal panel 2
After the video information is written by 5 and visualized by the polarizing plate 24, the dichroic mirrors 28-2, 28-
3 is combined and projected by the projection lens 26.

Also in this case, similarly to the first embodiment, the dimming polarizing plate 23 and the polarizing plate 24 are arranged such that their polarization axes are parallel to each other in the initial state, and the dimming polarizing plate 23 and the polarizing plate 24 are arranged in parallel with each other. The color balance of the image can be adjusted by rotating the system independently. In addition, the brightness of the image can be adjusted by rotating the dimming polarizing plate 23 in each of the RGB systems at the same angle at the same time.

[Embodiment 3] Similar to Embodiment 2, FIG. 5 shows an example of the configuration in the case of projecting after composition. In FIG. 5, the projection type liquid crystal display device includes a light source 31, a dichroic mirror or total reflection mirrors 38-1, 38-2, and 3.
8-3, 38-4, 38-5, collimator lens 32,
It is composed of a light control polarizing plate 33, a polarizing plate 34, a liquid crystal panel 35, a projection lens 36, and a dichroic prism 39.

The operation will be described with reference to FIG. The light output from the light source 31 is dichroic mirrors 38-1, 38.
-2, 38-3, and the intensity of each light incident on the liquid crystal panel 35 is adjusted by the inclination of the polarization axis between the dimming polarizing plate 33 and the polarizing plate 34 near the liquid crystal panel.
After that, the video information is written by the liquid crystal panel 35,
After being visualized by the polarizing plate 34, they are mixed by the dichroic prisms 39 and then projected by the projection lens 39.

Also in this case, similarly to the first embodiment, the dimming polarizing plate 33 and the polarizing plate 34 are arranged such that their polarization axes are parallel to each other in the initial state, and the dimming polarizing plate 33 and the polarizing plate 34 are respectively arranged in RGB. The color balance of the image can be adjusted by rotating the system independently. Further, the brightness of the image can be adjusted by rotating the dimming polarizing plate 33 in each of the RGB systems at the same angle at the same time.

[Embodiment 4] Embodiment 4 is shown in FIG. Figure 6
In the projection type liquid crystal display device, a light source 41, a dimming polarizing plate 43, a dichroic mirror or a total reflection mirror 48 is used.
-1, 48-2, 48-3, a collimator lens 42, a polarizing plate 44, a liquid crystal panel 45, and a projection lens 46. The configuration is similar to that of the first embodiment, but the fourth embodiment is different in that the light control polarizing plate 43 is disposed in front of the light source 41.

The light emitted from the light source 41 is used as a dimming polarizing plate 43.
After the light intensity is adjusted by, the color separation is performed and each light is projected by the projection lens 46 through the collimator lens 42, the polarizing plate 44, and the liquid crystal panel 45, and the color balance is not adjusted. [Fifth Embodiment] FIG. 7 shows a fifth embodiment. In Example 5, the projection type liquid crystal display device includes a light source 51, a dichroic mirror or a total reflection mirror 58-1, 58-2, 58-.
3, a collimator lens 52, a dimming polarizing plate 53, a polarizing plate 54, a liquid crystal panel 55, and a projection lens 56. Although the configuration is similar to that of the second embodiment of FIG. 4, the fifth embodiment is different in that the light control polarizing plate 53 is also arranged in front of the projection lens 51.

The light emitted from the light source 51 is adjusted by the dimming polarizing plate 53.
After the light intensity is adjusted by, the light is color-separated, each light passes through the collimator lens 52, the color balance is adjusted by the polarizing plate 54, and then the light is projected by the projection lens 56 through the liquid crystal panel 55. It Of course, it is also possible to adjust the overall brightness after adjusting the color balance. [Sixth Embodiment] A sixth embodiment is shown in FIG. In Example 6, the projection type liquid crystal display device includes a light source 61, a dichroic mirror or total reflection mirrors 68-1, 68-2, 68-.
3, a collimator lens 62, a dimming polarizing plate 63, a polarizing plate 64, a liquid crystal panel 65, a projection lens 66, and a dichroic prism 69. Although the configuration is similar to that of the third embodiment shown in FIG. 5, the sixth embodiment is different in that the dimming polarizing plate 63 is also arranged in front of the projection lens 61.

The light emitted from the light source 61 is used as a dimming polarizing plate 63.
After the light intensity is adjusted by, the color is separated and each light is transmitted through the collimator lens 52, and then the dimming polarizing plate 6
After the color balance is adjusted by 3, the image is projected by the projection lens 66 through the polarizing plate 64 and the liquid crystal panel 65.
Similar to the previous embodiment, the overall brightness can be adjusted after the color balance adjustment.

[Seventh Embodiment] FIG. 9 shows a seventh embodiment. In the seventh embodiment, the light source 71, the dichroic mirror or the total reflection mirrors 78-1, 78-2, 78-3, 78-4,
78-5, 78-6, collimator lens 72, polarizing plate 7
4, liquid crystal panel 75, light control polarizing plate 73, projection lens 7
It is composed of 6. Although the configuration is similar to that of the second embodiment of FIG. 4, the seventh embodiment is different in that the dimming polarizing plate 73 is arranged only in front of the projection lens.

In the initial state, the polarization axis of the dimming polarizing plate 73 is aligned with the polarization axes of the respective polarizing plates in parallel with each other, and the light intensity is adjusted by changing the angle of the dimming polarizing plate 73. be able to. [Embodiment 8] FIG. 10 shows an embodiment 8. In FIG. 10, the projection type liquid crystal display device includes a light source 31, a dichroic mirror or total reflection mirrors 88-1, 88-2, 88-.
3, 88-4, 88-5, collimator lens 82, polarizing plate 84, liquid crystal panel 85, dichroic prism 8
9, a dimming polarization plate 83, and a projection lens 86. The configuration is similar to that of the third embodiment shown in FIG. 5, except that the dimming polarizing plate 83 is arranged in front of the projection lens.

In the initial state, the polarization axis of the dimming polarizing plate 83 is aligned in parallel with the polarization axis of each polarizing plate, and the light intensity is adjusted by changing the angle of the dimming polarizing plate 83. be able to. [Embodiment 9] Embodiments 9 to 16 are embodiments in which the liquid crystal light control filter 97 is used. Example 9
Is shown in FIG. In Example 9, the projection liquid crystal display device includes a light source 91, a dichroic mirror or total reflection mirrors 98-1, 98-2, 98-3, and a collimator lens 9.
2, a polarizing plate 94, a liquid crystal dimming filter 97, a liquid crystal panel 95, and a projection lens 96.

In the ninth embodiment, the light output from the light source 91 is the dichroic mirrors 98-1, 98-2, 98.
The color is separated by -3 and collected by the collimator lens 92. Then, the polarizing plate 94 extracts the linearly polarized light component. The intensity of light incident on the liquid crystal panel 95 is adjusted by the optical rotation angle between the polarizing plate 94 and the liquid crystal light control filter 97. After that, image information is written by the liquid crystal panel 95, visualized by the polarizing plate 94, and then projected by the projection lens 96.

The liquid crystal dimming filter 97 adjusts the optical rotation angle by the applied voltage, so that fine adjustment is easy.
The color balance of the image can be adjusted by adjusting this independently for each RGB system. Further, the brightness of the image can be easily adjusted by adjusting the liquid crystal dimming filter 97 in each of the RGB systems simultaneously by the same ratio.
Although the ninth to twelfth embodiments are examples of synthesizing RGB images on the screen, the configurations shown in the thirteenth to sixteenth embodiments are used when projecting after synthesizing.

[Embodiment 10] An example of the construction of Embodiment 10 is shown in FIG.
2 shows. In FIG. 12, a light source 101, a dichroic mirror or total reflection mirrors 108-1, 108-2, 1
08-3, 108-4, 108-5, 108-6, the collimator lens 102, the polarizing plate 104, the liquid crystal light control filter 107, the liquid crystal panel 105, and the projection lens 106 are shown.

In FIG. 10, the light output from the light source 101 is the dichroic mirrors 108-1, 108-2,
108-3 color-separates and collimator lens 10
It is condensed by 2. After that, the linearly polarized light component is extracted by the polarizing plate 104. The intensity of light incident on the liquid crystal panel 105 is adjusted by the optical rotation angle between the polarizing plate 104 and the liquid crystal light control filter 107. After this, the liquid crystal panel 1
Video information is written by 05, visualized by the polarizing plate 104, and then combined and projected by the projection lens 106. The liquid crystal dimming filter 107 adjusts the optical rotation angle by the applied voltage, and therefore fine adjustment is easy. As in the ninth embodiment, it is possible to adjust the color balance of the image by adjusting this independently for each RGB system, and to adjust the brightness at the same time by adjusting the equal amount.

[Embodiment 11] FIG. 13 shows a configuration example of the embodiment 11. In FIG. 13, the projection type liquid crystal display device includes a light source 111, a dichroic mirror or mirror 118-1,
118-2, 118-3, 118-4, 118-5, a collimator lens 112, a polarizing plate 114, a liquid crystal dimming filter 117, a liquid crystal panel 115, a projection lens 116, and a dichroic prism 119 are shown.

In FIG. 11, after color separation, the respective lights are condensed by the collimator lens, pass through the polarizing plate 114, the liquid crystal light control filter 117, the liquid crystal panel 115, are combined by the dichroic prism 119, and are then projected. Lens 11
6 is projected. 19 and 20 show a configuration example in which a liquid crystal panel for video writing and a liquid crystal light control filter used in Examples 9 to 11 are laminated. Also,
21 and 22 show the case where a blocked liquid crystal light control filter is used.

FIG. 19 shows a case where the liquid crystal panels are laminated, but as shown in FIG. 20, two liquid crystal panels may be formed by integrating three glass substrates and integrated to make a compact size. By using the blocked liquid crystal light control filter shown in FIGS. 21 and 22, the applied voltage is changed for each block to change the transmitted light amount of each block, and the control for removing the uneven brightness of the panel is performed. The panel brightness can be kept constant. In this case, of course, the blocked liquid crystal light control filter can be used alone without being laminated.

[Twelfth Embodiment] FIG. 14 shows a twelfth embodiment. In Example 12, without adjusting the color balance,
This is a case where only brightness adjustment is performed. In Example 12, the projection type liquid crystal display device includes a light source 121 and a polarizing plate 12.
3, liquid crystal dimming filter 127, dichroic mirror 12
8-1, 128-2, 128-3, collimator lens 1
22, polarizing plate 124, liquid crystal panel 125, projection lens 1
It consists of 26.

In the twelfth embodiment, the linear component is extracted from the light of the light source 121 by the polarizing plate 127, and the amount of light entering the liquid crystal panel 125 is adjusted by the angle of rotation between the polarizing plate 123 and the light control filter 127. After that, the light that has been color-separated and imaged by the polarizing plate 124 is projected and combined on the screen. [Thirteenth Embodiment] FIG. 15 shows a thirteenth embodiment. The thirteenth embodiment, like the twelfth embodiment, is a case where only the brightness is adjusted without adjusting the color balance. Example 1
3, the projection type liquid crystal display device includes a light source 131, dichroic mirrors 138-1, 138-2, 138-.
3, 138-4, 138-5, 138-6, a collimator lens 132, a polarizing plate 134, a liquid crystal panel 135, a polarizing plate 133, a liquid crystal dimming filter 137, and a projection lens 136.

In the thirteenth embodiment, the color balance of the image after the color separation is not adjusted, and the brightness can be adjusted by the combined liquid crystal light control filter 137. [Embodiment 14] FIG. 16 shows Embodiment 14. The fourteenth embodiment, like the thirteenth embodiment, is a case where only the brightness is adjusted without adjusting the color balance.

In the fourteenth embodiment, the projection type liquid crystal display device includes a light source 141, dichroic mirrors 148-1 and 148-1.
48-2, 148-3, 148-4, 148-5, collimator lens 142, polarizing plate 144, liquid crystal panel 14
5, a dichroic film 149, a polarizing plate 143, a liquid crystal dimming filter 147, and a projection lens 146.

In the fourteenth embodiment, the color balance of the image after being decomposed is not adjusted, and only the brightness after being combined can be adjusted by the liquid crystal dimming filter 147. [Embodiment 15] Embodiment 15 is shown in FIG. Example 15
Is a liquid crystal filter 157 for dimming shown in FIG.
Is an example of using. The fifteenth embodiment has a configuration in which the light control polarizing plate 53 of the fifth embodiment is replaced with a light control liquid crystal panel 157, and the operation is exactly the same as that of the fifth embodiment. Here, the block liquid crystal light control filter shown in FIGS. 21 and 22 may be used alone as the liquid crystal light control filter to make the panel brightness uniform.

[Embodiment 16] Embodiment 16 is shown in FIG. Example 16 is also an example using the light control liquid crystal panel shown in FIG. 21 or FIG. Also in this case, the liquid crystal panel for dimming uses the liquid crystal dimming filter shown in FIG. 21 or FIG. 22 alone, and changes the applied voltage for each block of the block-shaped liquid crystal panel to change the transmitted light amount of each block. The panel brightness is controlled so as to eliminate the brightness unevenness of the panel. Example 16 is the same as Example 6.
In the configuration, the dimming polarizing plate 63 is replaced with the dimming liquid crystal panel 167, and the operation is exactly the same as in the sixth embodiment.

[0038]

As described above, according to the present invention, since the hue and brightness of an image can be adjusted without correcting the gradation of the liquid crystal panel (image writing section), it becomes complicated as the resolution becomes higher. A circuit for gradation correction becomes unnecessary. Therefore, these adjustments are facilitated and finer gradation display is possible, which greatly contributes to the performance improvement of the projection type liquid crystal display device. Also, since it can be electrically controlled, fine adjustment is possible.

[Brief description of drawings]

FIG. 1 is a diagram showing a basic principle 1 according to the present invention.

FIG. 2 is a diagram showing a basic principle 2 according to the present invention.

FIG. 3 is a diagram showing a first embodiment according to the present invention.

FIG. 4 is a diagram showing a second embodiment according to the present invention.

FIG. 5 is a diagram showing a third embodiment according to the present invention.

FIG. 6 is a diagram showing Embodiment 4 according to the present invention.

FIG. 7 is a diagram showing a fifth embodiment according to the present invention.

FIG. 8 is a diagram showing a sixth embodiment according to the present invention.

FIG. 9 is a diagram showing Embodiment 7 according to the present invention.

FIG. 10 is a diagram showing Embodiment 8 according to the present invention.

FIG. 11 is a diagram showing Embodiment 9 according to the present invention.

FIG. 12 is a diagram showing Embodiment 10 according to the present invention.

FIG. 13 is a diagram showing Embodiment 11 according to the present invention.

FIG. 14 is a diagram showing Embodiment 12 according to the present invention.

FIG. 15 is a diagram showing Embodiment 13 according to the present invention.

FIG. 16 is a diagram showing Embodiment 14 according to the present invention.

FIG. 17 is a diagram showing Embodiment 15 according to the present invention.

FIG. 18 is a diagram showing Example 16 according to the present invention.

FIG. 19 is a diagram showing a configuration example A of a laminated panel used in Examples 10 to 14.

FIG. 20 is a diagram showing a configuration example B of a laminated panel used in Examples 10 to 14.

FIG. 21 is a diagram showing a configuration example A of a blocked dimming liquid crystal panel used in Examples 15 to 16;

FIG. 22 is a diagram showing a configuration example B of a blocked dimming liquid crystal panel used in Examples 15 to 16;

FIG. 23 is a diagram showing a first conventional example.

FIG. 24 is a diagram showing a second conventional example.

FIG. 25 is a diagram showing a third conventional example.

[Explanation of sign]

1 Light source 2 Collimator lens 3 Light control polarizing plate 4 Polarizing plate 5 Liquid crystal panel 6 Projection lens 7 Light control liquid crystal filter 18, 28, 38, 48 Dichroic mirror or total reflection mirror) 39, 69, 99 129 Dichroic prism 210 Liquid crystal Light control cell 215 Blocked liquid crystal light control cell 220 Active matrix liquid crystal cell

Claims (2)

[Claims] 1. In a projection display device using a liquid crystal panel using a polarizing plate as a light valve, the amount of light is adjusted by rotating the polarization axis of a polarizing plate installed separately from the polarizing plate of the liquid crystal panel. A projection display device characterized by: 2. A liquid crystal display device using the liquid crystal panel as a light valve according to claim 1, wherein the amount of light is adjusted by a liquid crystal panel installed as a dimming filter installed separately from the liquid crystal panel used for image formation. Characteristic projection display device.