JPH02240630A - Projection type display device - Google Patents

Abstract

PURPOSE:To independently adjust the position of a liquid crystal panel and a focal point without requiring a special test pattern generator by incorporating a pattern generator in a projection type display device. CONSTITUTION:The pattern generator 25 is incorporated into the projection type display device possessing a driving circuit. A clock from a clock generator 24 is inputted to the pattern generator 25 generating a cross-shaped pattern, and a signal from the pattern generator 25 is inputted to switching circuits 5 to 7. They normally pass a signal from a video signal 1, and a signal from the pattern generator 25 when they are used as a pattern generator mode. Consequently, the projection type display device is obtained which can be used as a test chart when the position of three primary color liquid crystal panels are adjusted in all directions and which can be readily adjusted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a projection type display device using a transmission type light valve.

[Prior Art] As a projection type color display device using a conventional transmission type light valve, NisIday 86 Digest Publication No. 20
．． As shown in 4, a liquid crystal panel for a light valve dedicated to each of the three primary colors is used, and the light valve is irradiated with separated three primary color lights using a guichroic, a mirror, and a guichroic prism to form a color image. There was an example of that.

[Problems to be Solved by the Invention] When three liquid crystal panels are used for the three primary colors, a problem arises in that the positions of the three liquid crystal panels must be adjusted. At that time, we usually prepare a test pattern generator that generates vertical and horizontal line signals externally, and adjust the focus and vertical and horizontal positions of each color LCD panel without looking at the enlarged image projected on the screen. Was. For this reason, conventional projection type color display devices always require a test pattern generator when adjusting the position, which not only delays product throughput but also imposes space constraints.

In addition, if the LCD panel becomes distorted due to temperature, external photography, impact, etc., it will be extremely difficult to adjust it without a test pattern generator, and the manufacturer will have to readjust it. This made the product extremely inconvenient to maintain for users.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a projection type display device that has a built-in test pattern generator and can be easily adjusted.

[Means for Solving the Problems 1] A projection type display device of the present invention includes at least a transmissive light valve and a drive circuit for driving the transmissive light valve and displaying an image. It is characterized by having a built-in container.

[Example 1 Examples of the present invention will be described in detail below. FIG. 1 is a circuit block diagram of a projection type display device as an embodiment of the present invention. The operation of each part will be explained below along with the flow of signals.

The video signal 1 passes through the luminance-chrominance signal separation circuit 2, and the luminance (Y)
The six color signals 102 separated into the signal lot and the color (C) signal 102 pass through a delay circuit 4 for time adjustment with the luminance signal, and are input to the demodulation circuit 3 together with the luminance signal 101. The primary color signals are green (G) and blue (B). The red signal 103, green signal 104, and blue signal 105 pass through the switching circuit 5.6.7 and are input to the process circuit 8.9.10. The process circuit performs amplification, DC regeneration, gamma correction, etc., and AC drive circuits 11, 12, and 13 perform AC drive. AC primary color signal 109.
110 and 111 are input to the horizontal driver circuit 14 mounted on the red liquid crystal panel mounting board 26. Normally, this type of horizontal driver circuit is integrated. The horizontal driver circuit used here is of a type called a line sequential driving type, and is a type of writing one horizontal row of video signals to the source line 112 of the liquid crystal panel 18 at one time. still,
The liquid crystal panel shown in this example is a so-called active matrix type having one writing transistor per pixel.
It is a normally black type that blocks light when there is no signal. The horizontal driver 14 includes a sample and hold circuit 16 that temporarily holds the video signal, and a sample and hold circuit 16 that temporarily holds the video signal.
, and a buffer amplifier 17 for writing the signal held in the sample and hold circuit 16 to the source line 112 of the liquid crystal panel 18.

On the other hand, the video signal l is input to the synchronization separation circuit 22, where a synchronization signal is extracted and input to the PLL circuit 23.

The PLL circuit 23 generates a clock synchronized with the synchronization signal, and the clock generator 24 generates various clocks.The generated clocks are generated by the horizontal driver circuit 1.
These are start pulses 114 and shift pulses 115 for driving the shift register I4 of No. 4, and start pulses 116 and shift pulses 117 for driving the shift register 20 of the vertical driver circuit 19. Further, a clock is inputted from the clock generator 24 to a pattern generator 25 that generates a cross pattern. The signal from the pattern generator 25 is input to the switching circuits 5 and 6.7.The switching circuit 5.6.7 normally passes the signal from the video signal l, and when used in the pattern generator mode, the signal from the pattern generator 25 is input to the switching circuits 5 and 6.7. The signal from the device 25 is passed through.

FIG. 2 shows a signal waveform diagram generated by the pattern generator 25. Further, FIG. 3 shows a display image diagram based on a signal waveform diagram of the pattern generator 25. In FIG. It can be used as a test chart when adjusting the position of the three primary color liquid crystal panels in the vertical and horizontal directions. The signal that causes the vertical and horizontal black cursors to intersect in the center of the screen is as shown in Figure 2.
Within the horizontal period, a part of the center part of the white level is set to the black level, and the 130th line corresponding to the center part in the vertical direction is set to 0.
This can be obtained by setting the entire horizontal period to black level.

In this embodiment, a pattern generator that generates one black cursor in each vertical and horizontal direction is used, but even if the pattern generates multiple vertical and horizontal cursors, or if it is a circle or a curved cursor,
It may be characters, figures, etc.Also, in this embodiment, a black pattern on a white background is generated, but conversely, a white pattern on a black background may also be generated.Also, in this embodiment, Although the switching circuit switches between the video signal and the test chart from the pattern generator, it is also possible to display the test chart over the video signal by using a mixing circuit instead of the switching circuit. In the embodiment, a projection type display device using three liquid crystal panels for primary colors was shown, but a device using only two liquid crystal panels or a single panel projection type display device using only one liquid crystal panel can also be used. It is applicable. Furthermore, although an active matrix type liquid crystal panel was used as the liquid crystal panel in this embodiment, there is no problem even if it is a simple matrix type liquid crystal panel.Furthermore, although a line sequential driving type is shown as an example of the driving method of the liquid crystal panel, , a point-sequential driving method in which writing is performed pixel by pixel can be similarly applied.

〔Effect of the invention〕

As described above, the projection type display device of the present invention has a built-in pattern generator, so that the position adjustment and focus adjustment of the liquid crystal panel can be performed independently without the need for a special test pattern generator. became. This not only increases product throughput in the factory, but also allows for on-the-spot adjustments during maintenance services, making it possible to provide prompt service.

[Brief explanation of drawings]

FIG. 1 is a circuit block diagram of a projection type display device showing one embodiment of the present invention. FIG. 2 is a signal waveform diagram of a pattern generator built into the projection display device of the present invention. FIG. 3 is a display image diagram based on the signal waveform diagram of FIG. 2. 21...Buffer amplifier 27...Green liquid crystal panel mounting board 28...Blue liquid crystal panel mounting board 113...Data line or higher

Claims (1)

[Claims] (1) A projection display device comprising at least a transmissive light valve and a drive circuit for driving the transmissive light valve and displaying an image, the projection display device having a built-in pattern generator.