JPH06276535A - White balance detector and white balance adjustment device and adjustment method - Google Patents

Abstract

PURPOSE:To facilitate the adjustment of white balance by providing a diffusion means diffusing luminous flux, a sensor sensing color balance and a means leading only the luminous flux passing through the diffusion means to the sensor and to average color unevenness. CONSTITUTION:A luminous flux emitted from a liquid crystal projector 10 is given to a white balance detector 11, in which the light is subject to diffusion and averaging and the white balance is detected as an analog signal. The detected value is converted into a digital value at an A/D converter 4, processed by a microcomputer 5 and the detected data is stored in a memory 12 and a difference between the data stored in the memory 12 and white balance data detected is displayed on a display device 6. Thus, the white balance of the entire pattern resulting from averaging uneven color specific to the liquid crystal projector is sensed by one color sensor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to white balance adjustment of a projection type image display device such as a liquid crystal projector.

[0002]

2. Description of the Related Art Not only projection type projectors but also image display devices generally require white balance adjustment. In particular, projectors using liquid crystal as a light valve are caused by an optical system as compared with projectors using cathode ray tubes. Very uneven color. Therefore, it is very difficult to visually adjust the white balance, and considerable skill is required.
Even if a measuring device or the like is used, it cannot be said that the data reflects the white balance of the entire screen when measuring only one point. Therefore, in order to know the white balance of the entire screen, it is conceivable to measure the white balance at each part of the screen and take an average thereof.

FIG. 5 shows such a conventional technique. In this figure, 1 is a screen, 2 is a color sensor, and 9 are provided on the screen 1. 3 is a changeover switch,
Reference numeral 4 is an A / D converter, 5 is a microcomputer, and 6 is a detection level display.

In this conventional example, 9 is displayed on the screen 1.
Each individually arranged color sensor 2 detects the white balance at each place. The detection value is selected by the changeover switch 3, the A / D converter 4 converts it into a digital signal, and the microcomputer 5 performs processing such as averaging the outputs of the color sensors 2. Further, the microcomputer 5 displays the result on the display 6. The adjuster adjusts the white balance while looking at this display.

However, in this conventional white balance adjusting apparatus, a large number of color sensors 2 are required, and since it is necessary to sequentially switch the changeover switches 3 to calculate an average value, it takes a lot of time for processing. There is.

[0006]

SUMMARY OF THE INVENTION The present invention solves the problems of the prior art as described above, and provides a white balance adjusting device and an adjusting method which have a simple structure and can easily adjust the white balance. .

Further, the present invention provides a white balance detector most suitable for use in the white balance adjusting apparatus and the adjusting method.

[0008]

To this end, the white balance detector of the present invention comprises a diffusing means for diffusing a light beam,
It has a sensor capable of detecting the color balance and a means for guiding only the light flux passing through the diffusing means to the sensor.

The white balance adjusting apparatus of the present invention comprises the white balance detector, and a comparator for comparing the detection output of the white balance detector with a predetermined reference value and outputting the difference. ing.

Further, the white balance adjusting method of the present invention diffuses the projection light of the projection type image display device, detects the white balance of the projection light after the diffusion, and detects the detected white balance and a predetermined reference value. And the white balance of the projection type image display device is adjusted so that the difference is minimized.

[0011]

Since the white balance detector of the present invention is constructed as described above, the diffusing means diffuses the luminous flux of the projection type image display device to average the color unevenness.

[0012]

FIG. 1 shows an embodiment of a white balance detector according to the present invention. FIG. 1A is an exploded view and FIG. 1B is an assembly view. In FIG. 1, 7 is a diffusion plate, 8 is a color sensor unit on which the color sensor 2 is mounted, and 9 is a cylindrical portion that guides only the light flux that has passed through the diffusion means to the color sensor 2.

Next, FIG. 2 is a diagram showing the principle of the present invention. In FIG. 2, 10 is a liquid crystal projector, and it is assumed that an image is projected from the liquid crystal projector 10. Then, the light flux emitted from the liquid crystal projector 10 is diffused by the diffusion plate 7, and as a result, the color sensor 2 detects the averaged white balance of the color unevenness. In addition, as the diffusion plate 7, rubbing glass,
Any material such as semitransparent plastic or white paper that diffuses the light flux may be used.

FIG. 3 shows a first embodiment of the white balance adjusting apparatus according to the present invention. In this figure, 11 is the white balance detector shown in FIG. 1, and 12 is a memory that stores a reference value.

The light flux emitted from the liquid crystal projector 10 is diffused and averaged by the white balance detector 11, and the white balance is detected as an analog value. The detected value is converted to digital by the A / D converter 4, processed by the microcomputer 5, and the detected data is stored in the memory 12, or the white balance data detected by the display 6 and the memory 12 are stored. Display the difference from the data.

An example of actual adjustment using this adjusting device will be shown. First, the white balance of the standard liquid crystal projector 10 is measured, and the data is stored in the memory 12. Next, the liquid crystal projector 10 is set to the set to be adjusted instead of the standard machine, and the white balance is measured. This white balance data is compared with the reference value obtained from the standard machine and stored in the memory 12. On the display unit 6, the difference between each of the RGB colors and the standard machine is displayed, and the operator adjusts the white balance so as to approach the standard set while observing the difference.

FIG. 4 shows a second embodiment of the white balance adjusting apparatus according to the present invention. Although the same configurations as those in FIG. 3 are denoted by the same reference numerals and the description thereof is omitted, the difference between this embodiment and the first embodiment is that the liquid crystal projector 10 is equipped with an electronic volume 13 and is compatible with automatic adjustment. It is that you are. Therefore, in the first embodiment, the automatic adjustment is realized by controlling the electronic volume 13 by the microcomputer 5 while the operator adjusts it while looking at the display 6. The electronic volume 13 referred to here is a volume for adjusting the output of each color of RGB of the liquid crystal projector 10, and when adjusting the white balance, it is preferable to adjust the R output and the B output while leaving the G output as it is.

[0018]

As described above, according to the white balance detector of the present invention, the diffused light beam is received by the color sensor, so that the white balance of the entire screen in which the color unevenness peculiar to the liquid crystal projector is averaged is obtained. , Can be detected with only one color sensor.

Further, according to the white balance adjusting device and the adjusting method of the present invention, only one color sensor is required, the structure of the adjusting device is simplified, the skill of an adjuster is not required, and the adjusting time is short. The effect is great.

[Brief description of drawings]

FIG. 1 is a view showing an embodiment of a white balance detector according to the present invention.

FIG. 2 is a drawing for explaining the principle of the present invention.

FIG. 3 is a view showing an embodiment of a white balance adjusting device according to the present invention.

FIG. 4 is a view showing another embodiment of the white balance adjusting apparatus according to the present invention.

FIG. 5 is a drawing showing a conventional white balance adjusting device.

[Explanation of symbols]

 1 Screen 2 Color Sensor 3 Changeover Switch 4 A / D Converter 5 Microcomputer 6 Display 7 Diffuser 8 Color Sensor Unit 9 Cylindrical Section 10 Liquid Crystal Projector 11 White Balance Detector 12 Memory 13 Electronic Volume

Claims (3)

[Claims] 1. A white balance detector comprising: a diffusing unit for diffusing a light beam; a sensor capable of detecting a color balance; and a unit for guiding only the light beam that has passed through the diffusing unit to the sensor. 2. A white balance adjusting device comprising: the white balance detector according to claim 1; and a comparator which compares a detection output of the white balance detector with a predetermined reference value and outputs the difference. . 3. The projection light of a projection type image display device is diffused, the white balance of the projection light after the diffusion is detected, and the detected white balance is compared with a predetermined reference value. A white balance adjusting method for adjusting the white balance of the projection type image display device so as to minimize the white balance.