JPH04319930A - Image control device for light bulb image projector - Google Patents

Abstract

PURPOSE:To protect a light bulb unit, compensate the degradation of brightness with an image signal treatment circuit and keep projection without degradating the brightness feeling of a projected image, even when ambient temperature abnormally rises, by providing a control section to control the lighting power of a lamp with the temperature of the light bulb unit and the image signal treatment circuit to compensate the degradation of brightness on a screen when the lighting power of the lamp is lowered by the control section. CONSTITUTION:A lamp 1, a reflecting concave mirror 2, a lamp driving circuit 3, a converging lens 4, a light bulb unit 5, an image signal treatment circuit 6, a projection lens 7, a temperature sensor 8 and a control section 9 are provided. Even when the temperature of the light bulb unit 5 rises with abnormal ambient temperature rise, the control section 3 lowers the lighting power of the lamp 1 and treats image signals for the image signal treatment circuit 6 to compensate the lowering of the lighting power, so that projection effect is kept without degradating the brightness feeling of the image.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image control device for a light valve image projector using a light valve such as a liquid crystal image display device, which displays images on a large screen.

0002

2. Description of the Related Art In recent years, as television receivers have become larger in size, several types of projection television systems have been commercialized. One of these is a light valve video projector that uses a light valve such as an LCD video display device, which uses a powerful light source, so it is a challenge to protect the light valve and other parts from the heat. There is.

A conventional image control device for a light valve image projector will be explained below. FIG. 3 is a block diagram of a conventional image control device for a light valve image projector. In FIG. 3, 21 is a lamp serving as a light source, 22 is a condensing mirror for concentrating light emitted from the lamp 21 in one direction, 23 is a lamp drive circuit for lighting the lamp 21, and 24 is a light emitted from the lamp 21. Concave mirror 2 for direct light and condensing light
A condenser lens 25 condenses the light reflected by the condenser lens 24 again, and a liquid crystal display 25 displays images by controlling the light condensed by the condenser lens 24 in multiple stages from transmission to blocking. A light valve unit consisting of a device and two polarizing plates, 26 a video signal processing circuit for driving the liquid crystal display device of the light valve unit 25, and 27 projecting the light transmitted through the light valve unit 25 onto a screen. 28 is a temperature sensor that detects the temperature of the light valve unit 25; 29 is a switch connected to the power supply line of the lamp drive circuit 23; 30 is a projection lens that detects whether the temperature detected by the temperature sensor 28 may damage the light valve unit 25; This is a control unit that turns off the switch 29 and extinguishes the lamp 21 when the temperature exceeds the temperature that may cause damage.

The operation of the conventional image control device for a light valve image projector constructed as described above will be explained below. First, the lamp 21 is a light source for projecting onto a large screen of 100 inches or more and has a strong light output. The light emitted from this lamp 21 is collected by a concave mirror 2 for collecting light.
2, the light is focused by the condenser lens 24 and hits the light valve unit 25, so that the light valve unit 25 generates self-heating and a considerable temperature rise occurs. In such a light valve image projector, the light valve unit 25 is normally cooled by a cooling fan to prevent the light valve unit 25 from being damaged by heat.
The temperature of the light valve unit 25 may also rise due to an abnormal rise in the ambient temperature of the light valve image projector. When the temperature of the light valve unit 25 detected by the temperature sensor 28 exceeds a preset temperature, the control unit 30 turns off the switch 29, stops supplying power to the lamp drive circuit 23, and turns off the lamp 21. This prevents the expensive light valve unit 25 from being damaged by heat.

[0005]

However, in such a conventional configuration, the ambient temperature of the light valve image projector rises abnormally, and the temperature of the light valve unit 25 approaches a temperature that may cause damage. When this occurs, the lamp 21 is turned off, which naturally causes the problem that it becomes impossible to project an image.

The present invention solves the above-mentioned conventional problems, and provides an image of a light valve image projector that protects the light valve unit without turning off the lamp even if the ambient temperature of the light valve image projector increases. The purpose is to provide a control device.

[0007]

[Means for Solving the Problems] In order to achieve the above objects, the present invention includes a temperature sensor that detects the temperature of a light valve unit, and a light output of a lamp that is controlled based on the temperature of the light valve unit detected by the temperature sensor. 1. A video control device for a light valve video projector, characterized in that it is equipped with a control unit for controlling the light output of a lamp, and a video signal processing circuit that compensates for a decrease in brightness on a screen when the light output of a lamp is decreased by the control unit. It is.

[0008]

[Operation] With the above configuration, when the temperature sensor detects that the ambient temperature has risen abnormally and the temperature of the light valve unit has risen to a preset temperature, the control section reduces the light output of the lamp. By lowering the temperature of the light valve unit, it is possible to protect the light valve unit and continue to project images. In addition, in order to compensate for the decrease in brightness of the image on the screen due to the decrease in light output, R
The reduction in brightness is compensated for by a video signal processing circuit that can increase the GB drive, or increase the blue drive to increase the white color temperature to give an apparent sense of brightness, or both. It is possible to continue projecting images without reducing the brightness of the image.

[0009]

Embodiment An embodiment of the present invention will be described below with reference to FIG.

In FIG. 1, 1 is a lamp serving as a light source; 2 is a lamp serving as a light source;
3 is a condensing concave mirror for concentrating the light emitted from lamp 1 in one direction; 3 is a lamp drive circuit that can turn on lamp 1 and change the light output of lamp 1; 4 is lamp 1;
A condensing lens for condensing the direct light emitted from the condensing mirror 2 and the reflected light reflected by the condensing concave mirror 2, and 5 controls the light condensed by the condensing lens 4 in multiple stages from transmission to blocking. 6 is a light valve unit consisting of a liquid crystal image display device for displaying images and two polarizing plates; 6 is a light valve unit 5 for sending a video signal to the liquid crystal image display device; R;
A video signal processing circuit includes an amplifier circuit that can change the drive of each GB primary color signal, 7 is a projection lens for projecting the light transmitted through the light valve unit 5 onto the screen, and 8 is a light. A temperature sensor 9 that detects the temperature of the bulb unit 5 controls the lamp drive circuit 3 to reduce the light output of the lamp 1 when the temperature of the light bulb unit 5 detected by the temperature sensor 8 becomes higher than a preset temperature. It is also a control unit that sends information to the video signal processing circuit 6 that the optical output has been lowered.

The operation of the image control device for the light valve image projector constructed as described above will be explained. First, the lamp 1 is a light source for projecting onto a large screen of 100 inches or more, and has a strong light output. The light emitted from the lamp 1 is collected by the condensing concave mirror 2 and the condensing lens 4 and hits the light valve unit 5, so that the light valve unit 5 generates self-heating and undergoes a considerable temperature rise. In such a light valve image projector, the light valve unit 5 is normally cooled by a cooling fan to prevent the light valve unit 5 from being damaged by heat, but if the ambient temperature of the light valve image projector increases abnormally. etc., the temperature of the light valve unit 5 may also rise. When the temperature of the light valve unit 5 detected by the temperature sensor 8 exceeds a preset temperature, the control unit 9 controls the lamp drive circuit 3 to reduce the light output of the lamp 1, and the light valve unit 5 By lowering the temperature of the light valve unit 5, the light valve unit 5 is protected and at the same time images are continuously projected. At that time, the video signal processing circuit 6
In this case, the RGB drive is increased, and the blue drive is increased to give an apparent brightness, thereby increasing the white color temperature to compensate for the decrease in brightness, protect the light valve 5, and at the same time increase the brightness of the projected image. You can continue projecting without losing the quality of the image.

A second embodiment of the present invention will be described below with reference to the drawings. In FIG. 2, 11 is a lamp serving as a light source, 12 is a condensing mirror for concentrating light emitted from the lamp 11 in one direction, and 13 is capable of lighting the lamp 11 and changing the light output of the lamp 11. A lamp driving circuit 14 is a condensing lens for once again condensing the direct light emitted from the lamp 11 and the reflected light reflected by the condensing concave mirror 12; 15 is a condensing lens for condensing the light condensed by the condensing lens 14 from being transmitted; A light valve unit consisting of a liquid crystal image display device and two polarizing plates for displaying images through multi-step control until shutoff; 16 is an RGB light valve unit that sends image signals to the liquid crystal image display device of the light valve unit 15; A video signal processing circuit includes an amplifier circuit that can change the drive of each primary color signal, 17 is a projection lens for projecting the light transmitted through the light valve unit 15 onto the screen, and 18 is a light valve unit. This is a temperature sensor for detecting the temperature of No. 15, and the above structure is similar to that of FIG. The difference from the configuration in FIG. 1 is that the control unit 19 uses the light valve unit 15 detected by the temperature sensor
When the temperature of the lamp becomes higher than a preset temperature, the fan 20 is controlled to lower the temperature of the lamp 11 to reduce the light output and protect the light valve unit 15.

An image control device for a light valve image projector configured as described above will be explained. First lamp 1
If the light output is temperature dependent, such as a metal halide lamp, controlling the temperature of the lamp will also
The temperature of the light valve unit 15 can be lowered by controlling the light output. Therefore, as in the first embodiment, the temperature of the light valve unit 15 also rises due to an abnormal rise in the ambient temperature of the light valve image projector, and the temperature of the light valve unit 15 detected by the temperature sensor 18 changes from the preset temperature. When the temperature exceeds the specified temperature, the control unit 19 operates the cooling fan 20 directed toward the lamp 11 to lower the temperature of the lamp 11. Since the lamp 11 is temperature dependent, its light output decreases, and the temperature of the light valve unit 15 is lowered and protected. At the same time, similar to the first embodiment, the video signal processing circuit 16
increases the RGB drive, increases the blue drive to give an apparent brightness, and increases the white color temperature to compensate for the decrease in brightness, protects the light valve 5, and at the same time increases the brightness of the projected image. You can continue projecting without losing the quality of the image.

[0014]

As described above, the present invention provides a temperature sensor that detects the temperature of a light valve unit, a control unit that controls the light output of a lamp based on the temperature of the light valve unit detected by the temperature sensor, and a control unit that controls the light output of a lamp based on the temperature of the light valve unit detected by the temperature sensor. By providing a video signal processing circuit that compensates for the decrease in brightness on the screen when the light output of the lamp is decreased due to the
When the ambient temperature rises abnormally and the temperature of the light valve unit rises to the preset temperature, the control part will protect the light valve unit by reducing the light output of the lamp and lowering the temperature of the light valve unit. At the same time, it is possible to provide a video control device for a light valve video projector that can compensate for a decrease in brightness using a video signal processing circuit and continue projecting a projected video without reducing its brightness.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an image control device for a light valve image projector in a first embodiment of the present invention.

FIG. 2 is a block diagram of a video control device for a light valve video projector in a second embodiment of the present invention.

[Figure 3] Block diagram of a video control device for a conventional light valve video projector

[Explanation of symbols]

1 Lamp 2 Concave mirror for condensing light 3 Lamp drive circuit 4 Condensing lens 5 Light valve unit 6 Video signal processing circuit 7. Projection lens 8 Temperature sensor 9 Control section 11 Lamp 12 Concave mirror for condensing light 13 Lamp drive circuit 14 Condensing lens 15 Light valve unit 16 Video signal processing circuit 17 Projection lens 18 Temperature sensor 19 Control section 20 Fan 21 Lamp 22 Concave mirror for condensing light 23 Lamp drive circuit 24 Condensing lens 25 Light valve unit 26 Video signal processing circuit 27 Projection lens 28 Temperature sensor 29 Switch 30 Control section

Claims (1)

[Claims] 1. A lamp as a light source, a light valve unit for displaying an image, a temperature sensor for detecting the temperature of the light valve unit, and a temperature sensor that controls the light of the lamp based on the temperature of the light valve unit detected by the temperature sensor. A video control device for a light valve video projector, comprising a control unit that controls output, and a video signal processing circuit that compensates for a decrease in brightness on a screen when the control unit reduces the light output of a lamp.