JPH04270375A - Projection type liquid crystal display device - Google Patents

Abstract

PURPOSE:To improve the degree of freedom of a projecting position and to shorten the time required for setting by providing a rotary mirror, and a projection lens which rotates centering around a rotation axis of this mirror, and enlarges and projects a composite image onto a screen. CONSTITUTION:Light emitted from a light source 1 is condensed by a reflector, separated into spectral components of three primary color light of R, G and B by three pieces of dichroic mirrors 3-5, and is made incident on three pieces of black-and-white liquid crystal panels 6-8, respectively. To each liquid crystal panel 6-8, a driving signal is applied, and images based on RGB signals are displayed, respectively. As for the images which transmit through three pieces of black-and-white liquid crystal panels 6-8, one piece of composite image is obtained by dichroic mirrors 9-11. Also, this device is provided with a total reflection mirror 14 for rotating centering around a rotation axis being on a production of an optical axis of the composite image, and a projection lens 12 for rotating centering around the rotation axis of this total reflection mirror 14. In such a way, the composite image is enlarged and projected onto a screen 13.

Description

[Detailed description of the invention]

[Object of the invention]

0002

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type liquid crystal display device using a liquid crystal panel.

0003

[Background Art] In recent years, as video display devices have become larger in size,
It takes advantage of the small size and light weight of LCD panels because it is smaller and lighter than conventional CRT-type projection display devices, does not require troublesome convergence adjustment, and is not affected by the earth's magnetic field. Projection type liquid crystal display devices are attracting attention.

FIG. 6 is an explanatory diagram showing the structure of the optical system of such a conventional projection display device.

[0005] White light emitted from a light source 1 is collected by a reflector 2, separated into three primary color lights of RGB by three dichroic mirrors 3 to 5, and is incident on three black and white liquid crystal panels 6 to 8. . A driving signal is applied to each of the liquid crystal panels 6 to 8, and an image based on an RGB signal is displayed on each of the liquid crystal panels 6 to 8. Each image transmitted through three black and white liquid crystal panels 6 to 8 is
Three dichroic mirrors 9 to 11 combine the images into one image, which is magnified by a projection lens 12 and projected onto a screen 13.

[0006] Such a configuration has the problem that there is no degree of freedom in the projection position, and the housing 15 must always face the screen 13 perpendicularly. Therefore, there are problems in that it takes time to install the housing 15, and when the screen 13 is installed at an angle, screen distortion occurs, which is difficult to correct.

[0007]

[Problems to be Solved by the Invention] As described above, in the above-mentioned conventional projection display device, since there is no freedom in the projection position, it takes time to install it, and the screen must be installed at an angle. There is a problem in that it is not possible to correct screen distortion that occurs when the screen is distorted.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a projection type liquid crystal display device that can improve the degree of freedom of projection position, shorten installation time, and correct screen distortion. .

[Configuration of the invention]

0010

[Means for Solving the Problems] A projection type liquid crystal display device according to the present invention as set forth in claim 1 includes: a light source; a means for splitting white light from the light source into three primary color lights; a plurality of liquid crystal panels that output images of each color; means for optically superimposing images from the plurality of liquid crystal panels to obtain one composite image; and reflecting the composite image and extending the optical axis of the composite image. It is equipped with a mirror that rotates around a rotation axis on a line, and a projection lens that rotates around the rotation axis of this mirror and enlarges and projects the composite image onto a screen.

Further, the projection type liquid crystal display device according to the present invention as set forth in claim 2 includes a light source, a means for splitting the white light of the light source into three primary color lights, and a means for splitting the white light of the light source into three primary color lights, and displaying an image of each color using the three primary color lights. A plurality of liquid crystal panels to output, a means for optically superimposing images from the plurality of liquid crystal panels to obtain one composite image, and a means for reflecting the composite image and rotating on an optical axis extension line of the composite image. A mirror that rotates around an axis, a projection lens that rotates around the rotation axis of this mirror and enlarges and projects the composite image on a screen, and a mirror that rotates in conjunction with the rotation of this projection lens. and means for setting the rotation angle of the mirror to 1/2 of the rotation angle of the projection lens.

0012

[Operation] In the present invention, the optical axis of the composite image is rotated by rotating a mirror that totally reflects the composite image. Further, by rotating the projection lens around the rotation axis of this mirror, the elevation angle of the projection optical axis can be freely set. Moreover, by rotating the mirror and the projection lens in conjunction with each other, it is possible to perform projection so that the optical axes of the mirror and the projection lens are always aligned.

Furthermore, by setting the elevation angle of the projection optical axis in accordance with the inclination angle of the screen, the projection optical axis can always be set perpendicular to the screen surface.

[0014]

[Example] An example will be described with reference to the drawings.

FIG. 1 is an explanatory diagram showing the structure of an optical system of a projection type liquid crystal display device according to an embodiment of the present invention.

In FIG. 1, light emitted from a light source 1 is collected by a reflector 2, separated into three primary color lights of RGB by three dichroic mirrors 3 to 5, and transmitted to three black and white liquid crystal panels 6 to 8, respectively. It is incident. A drive signal is applied to each of the liquid crystal panels 6 to 8, and images based on RGB signals are displayed on each panel. The image transmitted through three black and white liquid crystal panels 6 to 8 is 3.
One composite image is obtained using the dichroic mirrors 9 to 11. Furthermore, by providing a total reflection mirror 14 that rotates around a rotation axis that is an extension of the optical axis of the composite image, and providing a projection lens 12 that rotates around the rotation axis of this total reflection mirror 14, the composite image can be created. The image is enlarged and projected onto the screen 13.

Next, the relationship between the rotation angle of the total reflection mirror and the change angle of the output optical axis of the composite image will be explained with reference to FIG.

As shown in FIG. 2, the total reflection mirror is [1]
Let θi be the incident angle of the optical axis of the composite image when it is at the position, θm be the rotation angle when the total reflection mirror rotates from the position [1] to the position [2], and the output optical axis of the composite image If the angle of change is θa, then equation (1) holds true because when the total reflection mirror is in position [2], the incident angle and the exit angle of the optical axis of the composite image are equal.

θi −θm =θi +θm −θa
(1) If the variation angle θa of the output optical axis of the composite image is calculated from this equation, it will be as shown in equation (2).

θa =2θm
(2) Therefore, the change angle θa of the output optical axis of the composite image is the rotation angle θm of the total reflection mirror.
It is twice as much. Here, in order to align the output optical axis of the composite image with the optical axis of the projection lens 12, it is necessary to rotate the projection lens 12 by an angle equal to the change angle of the output optical axis of the composite image. In other words, the rotational elevation angle of the projection lens 12 is θl
If this is the case, the total reflection mirror 14 may be rotated by θl/2.

Next, a case where the projection screen 13 is tilted will be explained with reference to FIG.

As shown in FIG. 3, at any projection position, the following equation holds true, where the inclination angle of the screen is θs, the elevation angle of the projection lens is θl, and the rotation angle of the total reflection mirror is θm.

[0023] θs = θl = 2θm
(3) When the relationship shown in equation (3) holds true, the projection optical axis becomes perpendicular to the screen, and it is possible to project onto the projection screen 13 without causing trapezoidal screen distortion.

FIGS. 4 and 5 are explanatory diagrams showing one embodiment of a mechanism for interlocking the total reflection mirror and the projection lens at the rotation angle explained in FIG. 2. FIG. 4 shows a side view, and FIG. 5 shows a plan view.

In these figures, 12 is a projection lens;
22 is the pillar of the projection lens, 14 is the total reflection mirror, 16 is the rotation axis of the projection lens, and 17 is the rotation axis 1 of this projection lens.
6 is a gear that rotates in conjunction with the gear 17; 18, 19, and 20 are gears that rotate in conjunction with the gear 17; and 21 is the rotation axis of the total reflection mirror. When the projection lens 12 is rotated around the rotation axis 16, the gear 17 that is interlocked with it rotates. Similarly, the gears 18, 19, and 20 rotate, and the total reflection mirror 14 fixed to the gear 20 rotates around the rotation axis 2 of the total reflection mirror.
It will rotate around 1. This rotating shaft 21 is coaxial with the rotating shaft 16. At this time, the gear 17,
If the rotation ratio of 18, 19, and 20 is set to 2:1:1:1, the total reflection mirror 14 will rotate by an angle that is half the rotation angle of the projection lens 12.

The interlocking mechanism between the total reflection mirror and the projection lens has, in addition to the mechanical structure as in the above embodiment, an electrical mechanism that detects the rotation angle of one and interlocks the other based on this. It is also possible to implement it with a similar circuit configuration.

[0027]

As described above, according to the present invention, the degree of freedom in the projection position can be improved and the time required for setting up the apparatus can be shortened. Another advantage is that trapezoidal screen distortion that occurs when the projection screen is tilted can be easily corrected.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the structure of an optical system of an embodiment of a projection type liquid crystal display device according to the present invention.

FIG. 2 is an explanatory diagram showing the relationship between the rotation of a total reflection mirror and the angle of change of a composite image output optical axis in an embodiment of the projection type liquid crystal display device according to the present invention.

FIG. 3 is an explanatory diagram showing the relationship among the rotation angle of the total reflection mirror, the rotation angle of the projection lens, and the tilt angle of the screen in an embodiment of the projection type liquid crystal display device according to the present invention.

FIG. 4 is a side view showing an embodiment of a mechanism for interlocking a total reflection mirror and a projection lens according to the present invention.

FIG. 5 is a plan view showing an embodiment of a mechanism for interlocking a total reflection mirror and a projection lens according to the present invention.

FIG. 6 is an explanatory diagram showing the structure of an optical system of a conventional projection display device.

[Explanation of symbols]

1...Light source 2...Reflector 3-5, 9-11...Dichroic mirror 6-8
...Black and white liquid crystal panel 12...Projection lens 13...Screen 14...Total reflection mirror 15...Housing

Claims (2)

[Claims] Claims: 1. A light source, means for separating white light from the light source into three primary color lights, a plurality of liquid crystal panels that output images of each color using the three primary color lights, and images from the plurality of liquid crystal panels. means for optically superimposing the images to obtain one composite image, a mirror that reflects this composite image and rotates around a rotation axis that is on the optical axis extension line of this composite image, and 1. A projection type liquid crystal display device comprising a projection lens that rotates around the center and projects the composite image on a screen in an enlarged manner. 2. A light source, means for separating white light from the light source into three primary color lights, a plurality of liquid crystal panels that output images of each color using the three primary color lights, and images from the plurality of liquid crystal panels. means for optically superimposing the images to obtain one composite image, a mirror that reflects this composite image and rotates around a rotation axis that is on the optical axis extension line of this composite image, and a projection lens that rotates around the center and enlarges and projects the composite image onto a screen; and a mirror that rotates in conjunction with the rotation of the projection lens, the rotation angle of the mirror being the rotation angle of the projection lens. 1
/2.