JPH03139637A - Liquid crystal video projector - Google Patents

Abstract

PURPOSE:To permit a single projector to be used for both vertical projection and axis-deviating projection by operating the device in such a manner that beams of light are condensed in a reflecting mirror, condensor lenses, and the pupil position of a projecting lens when the projecting lens is slid and shifted from the central axis of a liquid crystal panel in order to deviate its optical axis. CONSTITUTION:The liquid crystal video projector is provided with dichroic mirrors 20a-20d for separating light from a light source 12 into red, blue, and green. Also the device is provided with the projecting lens 13 for receiving lights outputted from the liquid crystal panels 16a-16c, which receive lights from the condenser lenses 14a-14c, respectively, and which are provided with a switching element for each picture element, and for projecting a formed picture element onto a screen. The device operates in such a manner that beams of light are condensed in the reflecting mirror 18a, the condenser lenses 14a-14c, and the pupil position of the projecting lens 13 when the projecting lens 13 is slid and shifted from the central axis of the liquid crystal panel in order to deviate its optical axis to a prescribed position. Thus, both the vertical projection and axis-deviating projection can be selected only by switching the inside composition.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a liquid crystal image projection device for enlarging and projecting an image onto a screen.

2. Description of the Related Art In recent years, liquid crystal image projection devices are expected to become widely used as a means for enlarging and projecting images.

An example of the above-mentioned conventional liquid crystal image projection device will be described below with reference to the drawings.

3, 4, 5, and 6 show the principle of a conventional liquid crystal image projection device, and FIG. 7 shows the principle of a conventional liquid crystal image projection device.

FIG. 8 shows the basic structure of a conventional liquid crystal image projection device.

In FIG. 3, FIG. 4, FIG. 5, FIG. 6, FIG. 7, and FIG. 8, 2 is the main body of the liquid crystal image projection device. Reference numeral 6 denotes a set stand, which is used when installing the liquid crystal image projection device 2 at an arbitrary height. 8 is the floor and 10 is the screen. Reference numeral 12 denotes a light source section that emits parallel light rays. A projection lens 13 projects an image. L4 (14a, 141),
Reference numeral 14c) is a condensing lens that focuses the light beam onto the pupil position of the projection lens 13. 16 (16a, 16b, 16
c) is a liquid crystal panel that is equipped with switching elements and displays video information. 1B (18a, 18b
, 18c) is a reflecting mirror. 20 (20a, 20b
20c, 20d) are dichroic mirrors that reflect only light of a specific wavelength.

The operation of the liquid crystal image projection device configured as described above will be described below.

FIG. 3 shows a method of projecting an image onto the screen 10 by placing the liquid crystal image projection apparatus main body 2 on a set table 6 of an arbitrary height. FIG. 4 shows a method of placing the main body of the liquid crystal image projection apparatus 2 on a low place such as the floor 8 and projecting an image onto the screen 10. FIG. 5 shows the principle of the liquid crystal image projection device in the case of FIG.
The liquid crystal panel 16 and the projection lens 13 are arranged so that their optical axes are aligned in a straight line. Therefore, the height of the center of the screen of the projected image and the center of the projection lens 13 match. FIG. 6 shows the principle of the liquid crystal image projection apparatus in the case of FIG. 4, in which the projection lens 13 is slid with respect to the liquid crystal panel 16 in a direction perpendicular to the optical axis. In other words, the axis is shifted, and the center of the screen of the projected image is projected upward from the center position of the projection lens 13. Even in that case, in order to prevent brightness from attenuating, the angle of the light source section 12 and condensing lens 14 must be changed so that they pass through the pupil position of the projection lens 13.

FIG. 7 shows a liquid crystal image projection device constructed based on the principle shown in FIG. The parallel light rays emitted from the light source section 12 are reflected by the reflecting mirror 18b. Only red light is reflected by the dichroic mirror 20a, reflected again by the reflecting mirror 18b, focused by the condenser lens 14a, and guided to the projection lens 13 through the liquid crystal panel 16a. Of the light that has passed through the dichroic mirror 20a, only blue light is reflected by the dichroic mirror 20b, focused by the condenser lens 14b, passed through the liquid crystal panel 16b, reflected by the dichroic mirror 20c, and sent to the projection lens 1.
Leads to 3. The light that has passed through the dichroic mirror 20b, that is, the green light, is focused by the condenser lens 14c, passes through the liquid crystal panel 16c, is reflected by the reflector 18c and the dichroic ink mirror 20d, and is guided to the projection lens 13. A liquid crystal panel 16a that emits red, blue, and green light, respectively;
16b and 16c are combined before the projection lens 13, and a color image is displayed on the screen.

FIG. 8 shows a liquid crystal image projection device constructed on the basis of the principle shown in FIG. Basically, the configuration is the same as that shown in FIG.
], 4c are arranged so that the light beam emitted from the light source section 12 passes through the pupil position of the projection lens 13.

Problems to be Solved by the Invention However, the above configuration has a problem in that the liquid crystal image projection device cannot be installed at an arbitrary height due to the difference in projection method.

In view of the above-mentioned problems, the present invention provides a liquid crystal image projection device that can select both vertical projection and off-axis projection with respect to the screen by switching the internal configuration.

Means for Solving the Problems In order to solve the above problems, the liquid crystal image projection device of the present invention includes a light source section that emits parallel light rays, a reflecting mirror for changing the optical path of the parallel light rays, and a light source section that directs the light from the light source section. a dichroic mirror for separating light into red, blue, and green; a condenser lens for converging parallel light; a liquid crystal panel that receives light from the condenser lens and has a switching element in each pixel; and the liquid crystal panel. a projection lens that receives output light from the panel and projects pixels formed on the liquid crystal panel onto a screen;
When the projection lens is slid and shifted from the central axis of the liquid crystal panel to a predetermined position, light rays are focused on the reflecting mirror and the condensing lens at the pupil position of the projection lens. It is designed so that it can operate as follows.

Operation According to the present invention, by changing the internal configuration, it is possible to select both vertical projection and off-axis projection with respect to the screen.

Embodiment Hereinafter, a liquid crystal image projection apparatus according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 and FIG. 2 are configuration diagrams of a liquid crystal image projection device according to an embodiment of the present invention.

In FIGS. 1 and 2, reference numeral 12 denotes a light source section that emits parallel light rays. A projection lens 13 projects an image. 14a, 14b, and 14c are condenser lenses that converge light rays to the pupil position of the projection lens 13.

16a, 16b, and 16c are liquid crystal panels that are equipped with switching elements and display video information.

18a, 18b, and 18c are reflecting mirrors. 20a, 20
b20c and 20d are dichroic mirrors that reflect only light of a specific wavelength. 15a15
b 15 c and 15 d are stoppers for positioning the reflecting mirror 18a. 13a
, 13b is a position detection lever. 22a and 22b are switches which are operated by being pressed by position detection levers 13a and 13b. lla, llb, Ilc, and lid are solenoids, and condenser lenses 14a, 14b,
14c and the reflecting mirror 18a can be set at one predetermined angle.

The operation of the liquid crystal image projection apparatus configured as described above will be explained below with reference to FIGS. 1 and 2.

The parallel light rays emitted from the light source section 12 are reflected by the reflecting mirror 18a. Only red light is reflected by the dichroic mirror 20a, reflected again by the reflecting mirror 18b, and focused by the condenser lens 14a, and the liquid crystal panel 16a
and is guided to the projection lens 13.

Of the light that has passed through the dichroic mirror 20a, only the blue light is reflected by the dichroic mirror 20b, is focused by the condenser lens 14b, passes through the liquid crystal panel 16b, is reflected by the dichroic ink mirror 20c, and is guided to the projection lens 13. It will be destroyed. The light that has passed through the dichroic mirror 20b, that is, the green light, is focused by the condenser lens 14c, passes through the liquid crystal panel 16c, is reflected by the reflecting mirror 18c and the dichroic mirror 20d, and is guided to the projection lens 13. LCD panel 1 that emits red, blue, and green light respectively
6a, 16b, and 16c are combined in front of the projection lens 13, and a color image is displayed on the screen. In this case, in FIG. 1, vertical projection is performed in which the central axis of the projection lens 13 and the center of the screen of the liquid crystal panels 16a16b to 16c coincide.

In FIG. 2, by sliding the projection lens 13, the central axis of the projection lens 13 and the liquid crystal panel 16a16b are
This results in axis-shifted projection in which the center of the screen of 16c is shifted. At this time, when the position detection lever 13a presses the switch 22a, the solenoids lla, llb, and 1lclid are activated, and the condenser lenses 14a, 14b,
14 c; One angle position of the reflecting mirror 18a can be corrected.

As described above, according to this embodiment, vertical projection and axis-shifted projection can be selected by sliding the projection lens 13.

Note that when the projection lens 13 is returned so that its central axis and the screen center of the liquid crystal panels 16a, 16b, 16c coincide with each other as shown in FIG. 1, the position detection lever 13b
The switch 22b operates, and the condensing lenses 14a, 1
4b14c and reflector 18a return to the angular position of FIG.

Effects of the Invention As described above, according to the present invention, a light source section that emits parallel light rays, a reflecting mirror for changing the optical path of the parallel light rays, and a mirror that separates the light from the light source section into red, blue, and green are provided. a dichroic mirror, a condenser lens for converging parallel light rays, a liquid crystal panel that receives light from the condenser lens and has a switching element in each pixel, and a liquid crystal panel that receives output light from the liquid crystal panel. a projection lens for projecting pixels formed on a screen onto a screen, and when the projection lens is slid and axially shifted from the central axis of the liquid crystal panel to a predetermined position, the reflecting mirror Then, the condenser lens can be operated so that the light beam is focused on the pupil position of the projection lens. Therefore, 1
The projector can be used for both vertical and off-axis projection.

[Brief explanation of the drawing]

1 and 2 are configuration diagrams showing mutually different states of a liquid crystal image projection device according to an embodiment of the present invention, and FIGS.
5, 6, 7, and 8 are block diagrams of conventional liquid crystal image projection apparatuses. 12...Light source section, 13...Projection lens, 14a, 14b14c...Condensing lens, 16
a, 16b, 16c...Liquid crystal panel, 18a
・・・・・Reflector, 20a, 20b, 20c, 20
d...Dichroic mirror

Claims (1)

[Claims] A light source unit that emits parallel light rays, a reflecting mirror that changes the optical path of the parallel light rays, a dichroic mirror that separates the light from the light source unit into red, blue, and green, and a condenser that focuses the parallel light rays. an optical lens; a liquid crystal panel that receives light from the condensing lens and includes a switching element in each pixel; and a projection system that receives light output from the liquid crystal panel and projects an image formed on the liquid crystal panel onto a screen. and a lens, when the projection lens is slid and axially shifted from the central axis of the liquid crystal panel to a predetermined position, the reflecting mirror and the condensing lens are connected to the pupil of the projection lens. A liquid crystal image projection device characterized in that it operates so that a beam of light is focused at a certain position.