JPH07336703A - Convergence adjustment device - Google Patents

Abstract

PURPOSE:To provide a convergence adjustment device in which convergence is easily adjusted with high accuracy. CONSTITUTION:The convergence adjustment is discriminated by the state of a control signal 5 whose state transits depending on whether or not the convergence is adjusted, and a video signal processing circuit 6 adjusts automatically a voltage of a video signal of an adjustment pattern to be received and a DC voltage of a low luminance to desired values. Thus, the contrast of the video signal of the adjustment pattern and a black level are adjusted automatically to desired values and convergence is easily adjusted with high accuracy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display device equipped with a convergence adjusting device.

[0002]

2. Description of the Related Art Generally, in a projection type projector, a projection tube for image formation consisting of CRTs for red (hereinafter, R), green (hereinafter, G), and blue (hereinafter, B) is arranged in a row. It is arranged. As a result, the image of each color on the screen is displaced, so that R, G, and B projected from each CRT
Convergence is adjusted so that the light beams of the book converge at the same point at any position on the screen.

An example of the convergence adjusting device will be described with reference to FIG.

In FIG. 2, the adjustment pattern output from the adjustment pattern signal generation circuit 1 for convergence adjustment.
The video signal 2 of the video signal and the video signal 3 other than when the convergence is adjusted are input to the switch 4. In the switch 4, a control signal 5 that changes its state depending on whether or not convergence adjustment is being performed
(The control signal 5 whose state changes depending on whether or not the convergence is adjusted will be referred to as a control signal 5 hereinafter), so that the image signal 2 of the adjustment pattern is output during the convergence adjustment and other than during the convergence adjustment. Outputs the video signal 3 other than when the convergence is adjusted. The image signal 2 of the adjustment pattern output from the switch 4 or the image signal 3 other than when the convergence is adjusted is input to the image signal processing circuit 6, and after adjusting the contrast and the black level, it is amplified,
It is applied to the cathode of CRT 7R, 7G, 7B. As a result, the image signal 2 of the adjustment pattern or the image signal 3 other than during the convergence adjustment is displayed on the CRT 7R, 7G, 7B.
Is displayed on the screen and magnified with the lenses 8R, 8G, and 8B,
It is displayed on the screen 9.

At the time of convergence adjustment, the adjustment pattern is displayed on the screen 9, and the light receiving element 10 arranged at each adjustment point on the screen 9 receives the light. Then, the light amount data received by the light receiving element 10 is input to the microcomputer 11 and processed to detect the position of the adjustment pattern,
Data for operating the convergence circuit 12 is created and input to the convergence circuit 12.

In the convergence circuit 12, based on the input data, the convergence yokes 13R and 13R attached to the CRTs 7R, 7G and 7B, respectively.
By passing a current through G and 13B, the magnetic field in the CRT is demagnetized, and the convergence on the screen 9 is adjusted. As a device related to this type, there is, for example, Japanese Patent Laid-Open No. 4-70086.

[0007]

In the above prior art, when the convergence is adjusted, the light amount data of the adjustment pattern received by the light receiving element 10 arranged at each adjustment point on the screen 9 is input to the microcomputer 11. By processing it,
The position of the adjustment pattern is detected. For this reason, when the difference in brightness between the high-luminance portion and the low-luminance portion of the adjustment pattern is small, the position detection accuracy of the adjustment pattern decreases, and thus the convergence adjustment accuracy decreases. For this reason, conventionally, before performing the convergence adjustment, the contrast and the black level are adjusted by the video signal processing circuit 6 so that the difference in luminance between the high-luminance portion and the low-luminance portion of the adjustment pattern is increased, and then the convergence is performed. I was making adjustments. But,
In this case, there is a problem that it takes time to adjust the contrast and the black level.

[0008]

The present invention comprises means for discriminating the state of the control signal 5 and automatically adjusting the contrast and the black level at the time of convergence adjustment.

[0009]

According to the present invention, for example, before the convergence adjustment is performed, the contrast and black level of the video signal processing circuit 6 are adjusted so that the difference in brightness between the high brightness portion and the low brightness portion of the adjustment pattern becomes small. Even if the adjustment is being performed, the state of the control signal 5 is discriminated to automatically increase the difference in brightness between the high-luminance portion and the low-luminance portion of the adjustment pattern when the convergence adjustment is started. Then, the video signal processing circuit 6 adjusts the contrast and the black level. As a result, when performing the convergence adjustment, it is possible to perform the convergence adjustment with high accuracy without taking time and effort.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a diagram showing a rear projection type projector incorporating a convergence adjusting device of the present invention. The projection type projector of this embodiment is an example using three CRTs of R, G and B.

In FIG. 1, the adjustment pattern output from the adjustment pattern signal generating circuit 1 for adjusting the convergence.
The video signal 2 of the input signal and the video signal 3 other than when the convergence is adjusted are input to the switch 4. The switch 4 determines the state of the control signal 5 to output the image signal 2 of the adjustment pattern during the convergence adjustment, and the image signal 3 other than during the convergence adjustment except during the convergence adjustment.
Is output. Here, for example, before the convergence adjustment, the video signal 3 output from the switch 4 except for the time of the convergence adjustment is input to the video signal processing circuit 6, the contrast and the black level are adjusted, and then amplified.
It is applied to the cathode of CRT 7R, 7G, 7B. As a result, the video signal 3 other than when the convergence is adjusted is CR.
Displayed on T 7R, 7G, 7B, lens 8R, 8G,
It is enlarged by 8B and projected onto the screen 9 or in the vicinity of the screen 9.

The switch 4 is used for adjusting the convergence.
The output video signal 2 of the adjustment pattern is input to the video signal processing circuit 6. At this time, the video signal processing circuit 6 discriminates that it is during convergence adjustment based on the state of the control signal 5, and automatically adjusts the contrast and black level of the video signal 2 of the adjustment pattern to desired values. Make adjustments. Here, the desired values of the contrast and the black level may be values that maximize the contrast and minimize the black level, for example.

Thereafter, the image signal 2 of the adjustment pattern for which the contrast and the black level have been adjusted is amplified and CR
It is applied to the cathodes of T7R, 7G and 7B. As a result, the video signal 2 of the adjustment pattern is displayed on the CRT 7R, 7G,
7B, magnified by the lenses 8R, 8G, and 8B, and projected on or around the screen 9.

At this time, the data of the amount of light received by the light receiving element 10 arranged around the screen 9 is converted into the microcomputer 11
The position of the adjustment pattern is detected by inputting to and processed to create data for operating the convergence circuit 12, and the data is input to the convergence circuit 12. The convergence circuit 12 biases the magnetic field in the CRT on the screen 9 by applying a current to the convergence yokes 13R, 13G, 13B attached to the CRTs 7R, 7G, 7B based on the input data. Adjust convergence at. Then, the state of the adjustment pattern after the operation of the convergence circuit 12 is detected again by the light receiving element 10, and the convergence circuit 12 is operated based on the data. The above series of operations are repeated, and the convergence adjustment is ended when the convergence is achieved.

When the convergence adjustment is completed, the control signal 5 indicates a state other than during the convergence adjustment. Therefore, the switch 4 outputs the video signal 3 other than during the convergence adjustment again to the video signal processing circuit 6. Is entered. At this time, the video signal processing circuit 6 determines from the state of the control signal 5 that it is not during the convergence adjustment, and sets the contrast and black level of the video signal 3 other than during the convergence adjustment to those before the convergence adjustment is started. To automatically adjust.

In this embodiment, eight light-receiving elements 10 are used, but the number of light-receiving elements 10 to be used may be appropriately determined in accordance with the size of the screen and the required accuracy of convergence adjustment. Further, the screen 9 of the present embodiment is not exclusively used for the convergence adjustment and is also used for the normal image. Therefore, the image projected on the screen is not interrupted at the time other than the convergence adjustment.
It is arranged around the screen 9. However, when the screen is dedicated to the convergence adjustment, the light receiving element 10 may be arranged on the screen 9.

The control signal 5 input to the video signal processing circuit 6 in this embodiment can be realized by using a control signal as shown in FIG. 3, for example. The control signal shown in FIG. 3 is an example of state transition to Hi level during convergence adjustment and to Low level before and after convergence adjustment, but the polarity of the control signal may be reversed.

In this embodiment, the control signal 5 input to the switch 4 and the video signal processing circuit 6 uses the same control signal. However, in some cases, for example, control signals having different control timings or polarities are used. Good.

In the present embodiment, the contrast and the black level can be adjusted by the control signal 5 by using the configuration shown in FIG. 4, for example. In FIG. 4, the control signal 5 input to the video signal processing circuit 6 is input to the video signal processing circuit control microcomputer 14. The video signal processing circuit control microcomputer 14 determines the state of the control signal 5, and outputs the control signal 15 for contrast adjustment and the control signal 16 for black level adjustment according to the state. Further, the video signal 17 output from the switch 4 is input to the video signal processing circuit 6, and in the contrast adjusting circuit and the black level adjusting circuit 18, the contrast adjusting control signal 15 and the contrast adjusting control signal 15 output from the video signal processing microcomputer 14 are output. By the control signal 16 for black level adjustment,
After being adjusted respectively, they are output from the video signal processing circuit 6.

[0020]

According to the present invention, for example, before performing convergence adjustment, the contrast and black in the video signal processing circuit 6 are reduced so that the difference in brightness between the high brightness portion and the low brightness portion of the adjustment pattern becomes small. Even when the level is adjusted, it is determined during the convergence adjustment that the convergence is being adjusted, based on the state of the control signal 5, and the contrast of the image signal 2 of the adjustment pattern input to the image signal processing circuit 6 and The black level can be automatically adjusted to a desired value to increase the difference in brightness between the high brightness portion and the low brightness portion of the adjustment pattern. Thereby, highly accurate convergence adjustment can be easily performed.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of a convergence adjustment device.

FIG. 3 is a diagram showing an example of a control signal of the present invention.

FIG. 4 is a diagram showing an example of a video signal processing circuit of the present invention.

[Explanation of symbols]

2 ... video signal of adjustment pattern, 3 ... video signal other than during convergence adjustment, 4 ... switch, 5 ... control signal that changes state depending on whether or not convergence adjustment is performed, 7R, 7G, 7B ... CRT, 8R, 8G, 8B ... Lens, 9 ... Screen, 10 ... Light receiving element, 13R, 13G, 13B ... Convergence yoke, 14 ... Image signal processing microcomputer, 15 ... Control signal for contrast adjustment, 16 ... Control signal for black level adjustment, 17 ... Video signal output from switch 4, 18 ... Contrast adjustment circuit and black level adjustment circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Misako Nakagawa, 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa, Ltd. Information & Video Media Division, Hitachi, Ltd. (72) Taiji Noguchi, 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Stock company Hitachi Media Media Research Laboratories (72) Inventor Yuichiro Kimura 292 Yoshida-cho, Totsuka-ku, Yokohama-shi Kanagawa Stock Company Hitachi Media Media Research Laboratories

Claims (3)

[Claims] 1. A convergence circuit for adjusting the convergence on the screen, an adjustment pattern signal generation circuit for generating a video signal of an adjustment pattern used for the convergence adjustment, and the adjustment pattern signal generation circuit. A video signal processing circuit for processing the video signal of the adjustment pattern output from
Image display means for displaying the image signal of the adjustment pattern output from the image signal processing circuit on the screen or around the screen; a light receiving element for detecting the adjustment pattern displayed on the screen or around the screen; In a convergence adjustment device equipped with a microcomputer that processes a detection signal from an element to control a convergence circuit, during the period when the convergence adjustment is being performed, the adjustment output from the adjustment pattern signal generation circuit is performed. Convergence adjusting device for automatically controlling in the video signal processing circuit such that the voltage amplitude of the pattern video signal (the voltage amplitude of the video signal is hereinafter referred to as contrast) has a desired value. . 2. A convergence circuit for adjusting the convergence on the screen, an adjustment pattern signal generation circuit for generating a video signal of an adjustment pattern used for the convergence adjustment, and the adjustment pattern signal generation circuit. A video signal processing circuit for processing the video signal of the adjustment pattern output from
Image display means for displaying the image signal of the adjustment pattern output from the image signal processing circuit on the screen or around the screen; a light receiving element for detecting the adjustment pattern displayed on the screen or around the screen; In a convergence adjustment device equipped with a microcomputer that processes a detection signal from an element to control a convergence circuit, during the period when the convergence adjustment is being performed, the adjustment output from the adjustment pattern signal generation circuit is performed. Automatic control in the video signal processing circuit so that the DC voltage of the low-luminance part of the pattern video signal (the DC voltage of the low-luminance part of the video signal is hereinafter referred to as black level) becomes a desired value. Convergence adjusting device. 3. A plurality of projection tubes (hereinafter CR
T), a lens for enlarging the image of the CRT, a screen for projecting the image enlarged by the lens, and a CR for adjusting the convergence on the screen.
A projection-type projector having a convergence yoke for demagnetizing a magnetic field in T, at least
A projection type projector comprising the convergence adjusting device according to claim 2.