JPH04120994A - Liquid crystal projector - Google Patents

Abstract

PURPOSE:To attain adjustment of convergence in a short time without causing dirt on the surface of a liquid crystal display panel by providing a setting means setting one color liquid crystal display panel among three color use liquid crystal display panels into a state not displaying electrically a video image to the projector in the case of the adjustment of convergence. CONSTITUTION:A switch circuit 18 applying/interrupting a video signal outputted from a video signal processing circuit 17 to/from each of liquid crystal display panels 6-8 is provided circuit section 10 in addition. Then the switch circuit 18 is controlled by a control circuit provided in the circuit section 10 similarly, that is, a control signal from a microcomputer 19 used for function control such as color tone or power supply of the liquid crystal projector. Thus, the convergence is adjusted simply in a short time without causing dirt on the surface of the liquid crystal display panels 6-8.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid crystal projector that combines images of red, green, and blue liquid crystal display panels and projects the images on a screen in an enlarged manner.

BACKGROUND OF THE INVENTION Conventionally, such a liquid crystal projector has been used, for example, as shown in FIG.
(1) is a light source that emits white light source light, (
2) is a reflecting mirror with a quadratic curved surface that is installed behind the light source (1) and reflects the white light source light from the light source (1) forward, and (3) is a reflector that is installed in front of the light source (1) and reflects the white light source light from the light source (1). and reflector (2
), heat-resistant glass that transmits white light source light from (4) (5
) converts the white light source light transmitted through the heat-insulating glass (3) into red light,
Dichroic mirror that separates green light and blue light,
(6) is a red liquid crystal display panel (7
) is a green liquid crystal display panel into which the green light that has been spectrally (reflected) by the dichroic mirror (5) is incident, and (8) is the liquid crystal display panel for the green color that receives the blue light that has been spectrally (transmitted) by the dichroic mirror (5) and is totally reflected. This is a liquid crystal display panel for blue light incident through a mirror (9). Here, each liquid crystal display panel (6)
(7) (8) is an electric shutter that blocks light only in the area where voltage is applied (that is, reduces the light transmittance), and separates red, green, and blue incident light according to the video signal. Images are displayed by modulating the signals, and the video signals (in this case, the three primary color signals of red, green, and blue) are supplied from the video signal processing circuit in the circuit section (10). There is. (11) and (12) are the red light modulated by the liquid crystal display panel (6) and passed through the total reflection mirror (13), and the green and blue light modulated by each liquid crystal display panel (7) and (8), respectively. The dichroic mirror (14) is a projector lens unit that enlarges and projects the composite light incident from the dichroic mirror (12) onto the screen (15). Each liquid crystal display panel (6) (7)
A color image is obtained by combining and enlarging the monochrome images in (8). Note that (16) is the main body of the projector.

However, in an LCD projector with such a configuration, convergence adjustment during production is carried out by superimposing a light shielding plate on one of the three LCD panels to control the optical path of that LCD panel. This was done by cutting off the current and then adjusting the convergence between the remaining two liquid crystal display panels.

For example, as shown in Figure 3, a red liquid crystal display panel (
6) A light shielding plate (17
) are overlapped to block the red light from this liquid crystal display panel (6) and the remaining green color.

After adjusting the convergence between the blue liquid crystal display panels (7) and (8), the light shielding plate (17) is placed on the exit side of the green liquid crystal display panel (7), and this liquid crystal display panel By blocking the green light from (7) and adjusting the convergence between the remaining red and blue liquid crystal display panels (6) (8), the three liquid crystal display panels (6) (7) ( 8) The convergence adjustment between

However, with such a conventional adjustment configuration, there is a risk of staining the surface of the liquid crystal display panel when the light shielding plate is overlapped with the liquid crystal display panel, and it is difficult to overlap the light shielding plate, which requires considerable effort and time. Therefore, it was not possible to perform convergence adjustment in a short time.

The present invention has been made in view of these points, and an object of the present invention is to provide a liquid crystal projector in which convergence adjustment can be performed in a short time without staining the surface of a liquid crystal display panel.

In order to achieve the above-mentioned object of reducing "I", in the present invention, in a liquid crystal projector that combines images from each liquid crystal display panel for red, green, and blue and enlarges and projects the images on a screen, when adjusting the convergence, A setting means is provided for electrically setting one color of each of the three color liquid crystal display panels to a state in which no image is displayed. Specifically, the setting means is connected to a video signal to the liquid crystal display panel. This is a switch circuit that supplies and cuts off the power, and is controlled by a microcomputer that is used to control other functions of the liquid crystal projector.

According to a configuration like Tomoji's, when adjusting the convergence of a liquid crystal projector, one of the three liquid crystal display panels for red, green, and blue, for example, is set to a no-signal state by a switch circuit. The switch circuit will be controlled by the existing microcomputer in the liquid crystal projector.

Example An embodiment of the present invention will be described below with reference to the drawings.

It should be noted that the same parts as those in the prior art will be given the same reference numerals and the explanation thereof will be omitted.

In this embodiment, the convergence adjustment of the liquid crystal projector is performed by setting one of the red, green, and blue liquid crystal display panels (in this case, one of the three panels) to a state where no image is electrically displayed. (in this case, a no-signal state) to cause this to occur. Specifically, as shown in FIG. 1, each liquid crystal display panel (6) (7) ( 8) A switch circuit (for example, a switch IC) that supplies and cuts off the supply to (1)
B) is separately provided in the circuit section (10), and this switch circuit (18) is connected to a control circuit also provided in the circuit section (10) (in this case, for controlling functions such as the color tone of the liquid crystal projector and the power source). microcomputer used) (19)
It is designed to be controlled by control signals from.

Therefore, in convergence adjustment in such a configuration, first, the switch circuit (18) is controlled by a control signal from the control circuit (19) in response to the switch operation of the selection section (20).
For example, as shown in Figure 1, after cutting off the green video signal supply and setting the green liquid crystal display panel (7) to a state in which it does not electrically display images (no signal state), the state The images from the red and blue liquid crystal display panels (6) and (8) (in this case, the circles projected on the display sections (6a) and (8a)) are enlarged and projected onto the screen (15) and displayed on the liquid crystal display. Perform convergence adjustment between panels (6) and (8). Then, in response to a control signal from the control circuit (19) in response to the next switch operation of the selection section (20), the switch circuit (18) cuts off the supply of the video signal for red color to the liquid crystal display panel for red color ( After setting 6) to a state where no image is displayed electrically, the image from the green and blue liquid crystal display panels (7) and (8) (in this case,
The ellipses projected on the display sections (7a) and (8a) are enlarged and projected onto the screen (15) to display the liquid crystal display panel (7a).
) (8), the convergence adjustment between each liquid crystal display panel (6), (7), and (8) is performed.

In this embodiment, the no-signal state is set during convergence adjustment, but the maximum applied voltage may be applied so that the transmittance becomes zero, and the liquid crystal display set to the no-signal state may be The panels are not limited to those for red and green, but may also be for blue. Further, in this embodiment, a case has been described in which there are three liquid crystal display panels for red, green, and blue, but there may be more than three liquid crystal display panels, for example, two liquid crystal display panels are used for each color. It can also be applied to pipe type ones.

Effects of the Invention As described above, according to the liquid crystal projector of the present invention, during convergence adjustment, one of the three color liquid crystal display panels is electrically set to a state in which no image is displayed. Therefore, convergence adjustment can be easily performed in a short time without staining the surface of the liquid crystal display panel unlike the conventional structure using a light shielding plate. In addition, the switch circuit that electrically sets the state in which images are not displayed is controlled by the microcomputer used to control other functions of the LCD projector, so the circuit configuration is relatively simple. It can be made into something.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing an example of the configuration of a liquid crystal projector suitable for implementing the present invention,
FIG. 3 is a diagram showing an example of a conventional configuration for convergence adjustment. (6) (7) (8) One liquid crystal display panel, (1
0)-Circuit section (17)--1 video signal processing circuit. (18)--switch circuit, (19)-control circuit.

Claims (3)

[Claims] (1) In a liquid crystal projector that combines the images of each liquid crystal display panel for red, green, and blue and enlarges and projects it on the screen, when adjusting the convergence, one of the liquid crystal display panels for each of the three colors is selected. A liquid crystal projector characterized in that it is provided with a setting means for electrically setting the projector to a state in which no image is displayed. (2) The liquid crystal projector according to claim 1, wherein the setting means is a switch circuit that supplies or cuts off video signals to the liquid crystal display panel. (3) The liquid crystal projector according to claim 1, wherein the switch circuit is controlled by a microcomputer used to control other functions of the liquid crystal projector.