JP2968711B2 - On-screen display method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-screen display system, and more particularly to a projection-type liquid crystal display device having two types of liquid crystal panels, a liquid crystal panel for displaying a transmissive image and a liquid crystal panel for on-screen. The present invention relates to a projection type liquid crystal display device capable of on-screen display in color.

[0002]

2. Description of the Related Art Conventionally, a display screen using this kind of on-screen display system has a display form as shown in FIG. The state of the screen at the time of performing the on-screen display is to display the on-screen signal by overwriting the character created as the on-screen on the video screen. The contents of the on-screen display often include an input signal display, a channel display, and a display for easily performing screen adjustment and the like. As an example, a case where screen adjustment is performed using on-screen display will be described. If the on-screen function includes a screen position adjustment item, first, on-screen display is performed to perform screen adjustment. When adjusting the position of the screen, a cursor or the like is displayed on the screen, and the screen is adjusted while watching the cursor or the like displayed on the image display screen and the on-screen. Performing screen adjustment by such a method has been put to practical use. Similarly, a channel display, an input signal display, and the like in which an on-screen signal is overwritten on a video signal have been put to practical use.

[0003]

The first problem is that, in the prior art, in the on-screen display system, characters and the like are displayed by overwriting on-screen information on a video display portion. Therefore, when adjusting the screen while watching the on-screen display, the color or character to be adjusted may be hidden below the on-screen character as shown in FIG.
When the video display screen has a character display, the character displayed on the screen may be bulky, so that the on-screen display is difficult to see. In particular, when a computer image is displayed, such a phenomenon is remarkable because the computer screen has a lot of character information.

In some cases, adjustment of a screen position, phase adjustment, and color adjustment are performed in on-screen display. In the adjustment of the screen position, the display position is determined by the relationship between the horizontal synchronization signal, vertical synchronization signal and the video signal, but in the case of a projection type liquid crystal display device, the display area of the liquid crystal and the position of the video signal output from the computer are adjusted There is a need to. Since the positions of the synchronization signal and the video signal are slightly different even in the same model of computer, the screen position of several dots to several tens of dots may be shifted. In this case, the screen position is adjusted to adjust the computer signal to the display area of the liquid crystal. At the time of this adjustment, an on-screen display is performed, and the adjustment is performed while viewing the adjustment screen and the on-screen. In this case, adjustment is performed in a limited display area without on-screen display. At this time, the necessary video screen was hidden by the on-screen display, so that it took a long time to perform the adjustment, or the adjustment could not be performed accurately. Similarly, when performing phase adjustment in a projection type liquid crystal display device, it is necessary to match one dot of a computer with one dot of a liquid crystal. At this time, if the display of the character or the like to be adjusted overlaps the on-screen display, the adjustment becomes difficult. Also, when performing color adjustment, the color to be adjusted may overlap the character color of the on-screen display.

[0005] The reason is that the above-mentioned problem occurs because the image display and the on-screen information are shared and displayed on one panel.

A second problem is that the frequency of a video signal or a synchronizing signal differs depending on the input device. The function of displaying video signals corresponding to different input frequencies when a personal computer, workstation, video signal, etc. is input is called multi-sync (hereinafter multi-sync). In the case of a multi-sync projection type liquid crystal display device In
The signal processing circuit for on-screen becomes complicated.

The reason is that the timing signal changes depending on the source of the input signal. That is, since the on-screen timing signal also changes according to the input signal, it is necessary to generate an on-screen timing signal corresponding to each signal. Further, in order to display the video signal with the on-screen signal superimposed thereon, it is necessary to switch and display the video signal and the on-screen display signal, so a switching circuit is required. When the video signal has a high frequency, it is difficult to match the timing of switching between the on-screen signal and the video signal and the phase of each signal.

It is an object of the present invention to provide an on-screen display system in which screen adjustment is easy and the circuit configuration can be simplified.

[0009]

According to the present invention, there is provided an image signal input system for inputting light from a light source to a liquid crystal panel for displaying an image signal, and on-screen display of the light from the light source via a total reflection mirror. An on-screen signal incidence system that enters the liquid crystal panel for display, and a projection optical system that combines the video signal from the liquid crystal panel for video signal display and the on-screen signal from the liquid crystal panel for on-screen display to project and display the screen. A liquid crystal panel for on-screen display.
The panel is a single panel capable of color display, and
Image signal display liquid crystal panel for three primary colors of red, green and blue
Three dichroic mirrors for color separation and color
It is arranged between the dichroic mirror for composition and operates the timing signals of the video signal and the on-screen signal independently, and it is possible to adjust the screen on-screen while viewing all the information on the video screen An on-screen display system characterized by the following is obtained.

[0010]

[0011]

Further, according to the present invention, light from a light source is reflected only by a blue reflection / separation dichroic mirror, and the blue light is converted into a blue light by a video signal display liquid crystal panel and an on-screen display liquid crystal panel. The green light and the red light that have passed through the liquid crystal panel are converted into a video signal and a blue light signal as an on-screen signal, and have passed through the blue reflection / separation dichroic mirror. Only is reflected, the green light passes through a green liquid crystal panel including a video signal display liquid crystal panel and an on-screen display liquid crystal panel, and is converted into a green light signal as a video signal and an on-screen signal,
The green light signal is incident on the blue transmission / combination dichroic mirror together with the blue light signal, and the blue transmission / combination dichroic mirror emits a blue / green light combination signal obtained by combining the green light signal and the blue light signal. The red light transmitted through the green reflection separating dichroic mirror passes through a red liquid crystal panel including a video signal display liquid crystal panel and an on-screen display liquid crystal panel, and serves as a video signal and an on-screen signal. The red light signal is converted into a red light signal, and the red light signal is incident on a red reflection synthesizing dichroic mirror together with the blue-green light synthesizing signal. The blue-green-red light composite signal is projected and displayed on a screen via a projection optical system, and the video signal and the
Independent timing signal for each on-screen signal
Operating on the screen.

[0013]

A signal is displayed on a screen by using two types of liquid crystal panels, a liquid crystal panel for displaying images and a panel for on-screen. Therefore, the video signal and the on-screen signal do not become difficult to see due to the overlap of the video signal with the on-screen signal.

In the case of a multi-sync projection type liquid crystal display device, a timing signal of a video signal changes due to a change in an input signal. Can operate independently. Therefore, the circuit configuration can be realized without being affected by the input signal, and the circuit configuration is simple.

[0015]

Next, embodiments of the present invention will be described with reference to the drawings. First, a first embodiment of the present invention will be described. As shown in FIG.
A liquid crystal panel 2 for image display which receives light from the light source, one system for inputting an optical signal passing through the panel to a projection optical system 4, and on-screen display of light from the light source 1 using total reflection mirrors 5 and 6. To the liquid crystal panel 3 for use, and a total reflection mirror 7,
The system 8 is used to project a light beam incident on the projection optical system 4 onto a combined screen 11.

Next, the operation of the first embodiment will be described in detail with reference to FIG. Light from a light source 1 is made incident on a liquid crystal panel 2 for video signal display capable of performing color display on a single plate. That is, by transmitting light through the liquid crystal panel 2 for displaying a video signal, a color video signal is passed. The transmitted color video signal enters the projection optical means 4 and is enlarged and projected on the screen 11. On the other hand, the light reflected by the total reflection mirrors 5 and 6 from the light source 1 is incident on the on-screen display liquid crystal panel 3. When the incident light passes through the on-screen display liquid crystal panel 3, the on-screen information is converted into an optical signal (on-screen signal), reflected by total reflection mirrors 7 and 8, incident on the projection optical unit 4 and screen. It is enlarged and displayed at 11.
The optical signals generated by the two types of systems, the video signal display liquid crystal panel 2 and the on-screen display liquid crystal panel 3, are synthesized and displayed on the screen.

FIG. 2 shows an example of a screen display area when actually projecting. The on-screen display liquid crystal panel 3 can change the display position of the on-screen signal to the upper part of the video signal depending on the arrangement in the projection type liquid crystal display device. Further, since the timing signal used for the on-screen display liquid crystal panel 3 has no correlation with the video input, the on-screen signal can always be generated with a constant control signal.

FIG. 3 shows an example of a display screen when actually projecting on the screen. From FIG. 3, it can be understood that the on-screen display is performed without overlapping the video display portion. The on-screen display liquid crystal panel 3 used in the above-described first embodiment can perform color display by using a single-panel color liquid crystal panel. Also,
By using a single-panel, single-color liquid crystal panel, a low-cost on-screen circuit can be realized.

Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 4 is a configuration diagram showing a second embodiment of the present invention. Light obtained from the light source 1 reflects only the B light by a blue light (hereinafter, referred to as B light) reflecting dichroic mirror. The B light is totally reflected by the total reflection mirror 54 and passes through the B light video signal display liquid crystal panel 59 and the B light on-screen display liquid crystal panel 62. The passed optical signal passes through the color synthesizing dichroic mirrors 55 and 56 and enters the projection optical unit 4. In the light passing through the B light reflecting dichroic mirror 51, only the G light is reflected by the green light (hereinafter referred to as G light) reflecting dichroic mirror 52, and the G light image signal display liquid crystal panel 58 and the G light on-screen display Incident on the liquid crystal panel 61. The incident light is converted into a video signal and an on-screen signal into optical signals, reflected by the color synthesizing dichroic mirror 55, and further passes through the color synthesizing dichroic mirror 56. Then, the light enters the projection optical unit 4. Finally, the red light (hereinafter, referred to as R light) passes through the G light reflecting dichroic mirror, enters the R light video signal display liquid crystal panel 57 and the R light on-screen display liquid crystal panel 60, and outputs the respective signals. The light is converted into an optical signal, reflected by the total reflection mirror 53, and further reflected by the dichroic mirror 56 for color synthesis, so that the light enters the projection optical unit 4. The R, G, and B optical signals are enlarged by the projection optical unit 4 and displayed on the screen 11. A display image screen similar to that shown in FIG. 3 is obtained. Therefore, in the above-described configuration using the video signal display liquid crystal panel and the on-screen display liquid crystal panel for R, G, and B, it is possible to realize high-definition color display.

Next, a description will be given of a third embodiment obtained by combining the above-described first embodiment and the above-described second embodiment. The configuration is shown in FIG . As for the optical path through which the video signal passes, as described in the second embodiment, the R light, G light, and B light signals are individually controlled, and for the on-screen signal, the first light is used. As shown in the embodiment, control is performed via the on-screen display liquid crystal panel 3 so that the video signal and the on-screen signal are finally made incident on the projection optical unit 4, and they are combined to form the The synthesized signal is enlarged and projected. Therefore, in the video signal display portion, high-definition video signals are displayed using three liquid crystal panels for R light, G light, and B light, and in the on-screen signal display portion, color display or monochrome display on a single plate is performed. By using a liquid crystal panel that can be used, the on-screen display system of the present invention can be realized.

[0021]

The first effect of the present invention is that on-screen characters do not overlap with a video signal so that they are difficult to see. This makes it possible to easily adjust the screen while watching the on-screen. The reason for this is that it has two types of panels, a video signal display liquid crystal panel and an on-screen display liquid crystal panel.

The second effect of the present invention is that the circuit configuration can be simplified. In the conventional circuit configuration, a video signal and an on-screen signal are switched in one screen, so a switching circuit is required. Further, in the case of a video signal having a high frequency, it is necessary to match the phase of each signal to display the on-screen signal superimposed on the video signal, so that the circuit is complicated. According to the present invention, the above-mentioned problems are solved, so that the cost of parts and the number of development steps can be reduced. The reason is that the on-screen display liquid crystal panel does not depend on the input signal, so that the on-screen display system can always be configured with a constant control signal.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a first embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of a screen display area when projection is performed.

FIG. 3 is a diagram showing an on-screen display screen according to the present invention.

FIG. 4 is a diagram for explaining a second embodiment of the present invention.

FIG. 5 is a diagram for explaining a third embodiment of the present invention.

FIG. 6 is a diagram showing an on-screen display screen according to a conventional method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light source 2 Liquid crystal panel for video signal display 3 Liquid crystal panel for on-screen display 4 Projection optical means 5, 6, 7, 8 Total reflection mirror 10 Projection type liquid crystal display device 11 Screen

Claims (2)

(57) [Claims] 1. A video signal input system for inputting light from a light source to a video signal display liquid crystal panel, and an on-screen signal input for inputting light from the light source to an on-screen display liquid crystal panel via a total reflection mirror. system and the having a projection optical system that projects and displays on a screen an on-screen signal from the video signal and the on-screen display liquid crystal panel combined and from the video signal display liquid crystal panel, the on-screen display liquid crystal panel Is a veneer color
The liquid crystal panel for displaying a video signal can be displayed in three colors, red, green and blue.
Three color dichroic mirrors for color separation
And the timing signal of the video signal and the on-screen signal are operated independently, and the on-screen screen is viewed while viewing all information of the video screen. An on-screen display system that can be adjusted. 2. The light from a light source is reflected only by a blue reflection / separation dichroic mirror on blue light, and the blue light passes through a blue liquid crystal panel comprising a video signal display liquid crystal panel and an on-screen display liquid crystal panel. The green light and the red light which are converted into a blue light signal as a video signal and an on-screen signal through the blue reflection separation dichroic mirror enter the green reflection separation dichroic mirror, and only the green light is reflected. The green light passes through a green liquid crystal panel including a video signal display liquid crystal panel and an on-screen display liquid crystal panel, and is converted into a green light signal as a video signal and an on-screen signal, and the green light signal is the blue light signal. Is incident on the dichroic mirror for blue transmission synthesis, and the green light signal and the green light signal are transmitted from the dichroic mirror for blue transmission synthesis. A blue-green light composite signal synthesized with the color light signal is emitted, and the red light transmitted through the green reflection separating dichroic mirror passes through a red liquid crystal panel including a video signal display liquid crystal panel and an on-screen display liquid crystal panel. Is converted into a red light signal as a video signal and an on-screen signal, and the red light signal is incident on the red reflection synthesizing dichroic mirror together with the blue-green light synthesizing signal, and they are synthesized from the red reflection synthesizing dichroic mirror. And the combined blue-green-red light is projected and displayed on a screen via a projection optical system, and the timing signals of the video signal and the on-screen signal are operated independently. An on-screen display method characterized by the following.