JPS64707B2 - - Google Patents

Description

[Detailed Description of the Invention] <Technical Field> The present invention relates to a CRT that connects a personal computer to a television receiver and simultaneously displays data images from the personal computer by superimposing them on a CRT screen with television broadcast images. This invention relates to a display device.

Recently, personal computers have come to be used in ordinary households. Attempts are now being made to connect a home color television receiver as a CRT display device to a personal computer and display data from the personal computer on the color television receiver.

<Prior art> Figure 1 shows a general technology in which a personal computer is connected to a color television receiver.
1 is a schematic diagram of a CRT display device. First, referring to FIG. 1, when data entered from the keyboard 1 is input into the personal computer 2,
R, G, and B signals for displaying the data on the color television receiver 3 are applied to a signal mixing circuit 32 included in the television circuit 31.
Then, the R, G, and B signals are applied to the CRT 33 via the signal mixing circuit 32, and characters or graphs are displayed.

By configuring the CRT display device in this manner, data images such as various characters and graphs can be displayed using the color television receiver 3 as a monitor. Furthermore, recently, CRTs, which display data from personal computers superimposed on color television broadcasting screens, have become popular.
A display device has been devised.

<Problem> By the way, with such a CRT display device, television images (not only broadcast images)
Since data images from a personal computer are superimposed and displayed on images played back by a VTR or video disk player, etc., depending on the content of the television image, for example, characters or graphs may be included in news programs or educational programs. In such cases, the user may confuse the data image with the data from the personal computer.
There was a drawback that it was difficult to immediately identify which image it was.

<Purpose> The present invention has been made in view of the above points, and is intended to prevent the user from confusing the two images in a device that can simultaneously project and display a television image and a data image from a personal computer on a CRT screen. The purpose of the present invention is to provide a CRT display device that is free from the risk of such occurrence.

Particularly, the present invention provides a CRT display device that allows a user to easily identify which image the data image is by adding shading with appropriate contrast to the data image from a personal computer.

<Example> The present invention will be described below according to an example shown in the drawings. FIG. 2 shows a block diagram of an embodiment of the present invention, in which the same parts as in FIG. 1 are given the same reference numerals. Here, in particular, the shadow signal creation circuit 9 consisting of the OR gate 4, the monostable multivibrator 5, the buffer amplifier 6, the transistor 7, the variable resistor 8, etc., and the magnitude of the shadow signal created by this shadow signal creation circuit 9 are adjusted. a variable resistor 10 for adjusting shadow contrast, and a transistor 11,
12 and a shadow signal mixing circuit 15 consisting of buffer amplifiers 13, 14 and the like.

Now, in the CRT display device of the above embodiment, the data output from the personal computer 2 is displayed on the CRT screen as shown in FIG. 3a.
The operation when R, G, and B outputs are derived to display a character image will be described.

In this case, at least one of the R, G, and B outputs of the personal computer 2 is derived as an "H" output on the line that crosses the character 〓〓 on the CRT screen, for example, the A-A' line.
A rectangular wave pulse as shown in FIG. 3b is derived from the OR gate 4, and a monostable multivibrator 5
is supplied to At this time, the monostable multivibrator 5 is triggered by the falling edge of this pulse, and outputs a positive one-shot pulse with a constant pulse width _T0 as shown in Fig. 3c.
Supplied to the base of transistor 7. The transistor 7 is turned on only during this pulse period, and an inverted pulse signal of negative polarity is derived from the collector as shown in FIG. 3d, and this is supplied to the shadow signal mixing circuit 15 as a shadow signal. At this time, in the shadow signal mixing circuit 15, the aforementioned shadow signal is supplied to the base of the transistor 12 through the buffer amplifier 13. Furthermore, the television luminance signal (Y signal) obtained from the television circuit 31 is inverted and inputted to the base of this transistor 12, and when the negative polarity shadow signal is added, that is, a shadow signal is input. In this section, the Y signal is temporarily cut off. On the other hand, buffer amplifier 1
After the magnitude of the shadow signal obtained through 4 is appropriately adjusted by a variable resistor 10 for adjusting shadow contrast, it is supplied to a signal mixing circuit 32 in a television circuit 31. Note that when there is no shadow signal, the Y signal obtained from the television circuit 31 is amplified by the transistors 11 and 12, and then the Y signal is amplified by the signal mixing circuit 32 of the television circuit 31 again.
will be returned to. That is, in this manner, the shadow signal is mixed with the Y signal in the shadow signal mixing circuit 15, and the Y signal (Y') mixed with the shadow signal is supplied to the signal mixing circuit 32 of the television circuit 31.

As a result, the third screen appears on the CRT33 screen.
The trailing edge of the character image from the personal computer 2 as shown in FIG.

In the above embodiment, the width of the shadow projected on the screen is determined by varying the value of the output pulse width To of the multivibrator 5 using a pulse width adjustment variable resistor 8 attached to the monostable multivibrator 5. It can be set arbitrarily by
However, in this case, if the pulse width To is made so wide that the shadow of a character on the screen overlaps a part of the adjacent character image, or if the horizontal distance between the character itself or adjacent characters is narrow, even if the monostable multivibrator Even when a positive one-shot pulse is being output from the output terminal 5, the output of the OR gate 4 becomes "H" level due to the subsequent character output derived from the personal computer 2, and the output of the amplifier 6 also becomes "H" level. Therefore, at this time, the transistor 7 is in a cut-off state, and therefore no shadow signal is derived from the collector. On such a result screen, the shadow of one character will not erode part of the adjacent character.

Furthermore, in this embodiment, by appropriately adjusting the value of the variable resistor 10 for adjusting shadow contrast,
It is possible to arbitrarily set the intensity of the shading added to the trailing edge of the character image on the CRT screen.

In the above embodiment, a color television receiver and a personal computer are connected, and a CRT is used.
We have described the case of adding black shading to color characters from a personal computer on the screen, but of course it is also possible to add color shading as appropriate.Also, when a black and white television receiver is connected to a personal computer, can also be implemented.

<Effects> As described above, according to the present invention, a personal computer is connected to a television receiver, and a CRT
In a CRT display device that can simultaneously project and display data images from a personal computer on the screen, superimposing them on the television image, the data images from the personal computer are shaded with arbitrary contrast, so the user can The background television image and this data image can be immediately distinguished, so even if characters or data are displayed on the screen in a news program broadcast on television, confusion may occur. Never.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of a CRT display device in which a personal computer is connected to a color television receiver, Fig. 2 is a block diagram of an embodiment of the present invention, and Fig. 3 is a diagram for explaining the operation of the embodiment.
It is an example of a CRT screen and a signal waveform diagram at that time. 2...Personal computer, 3...Color television receiver, 32...Signal mixing circuit, 3
3...CRT, 9...Shading signal creation circuit, 10...
...Variable resistor for adjusting shadow contrast, 15...Shadow signal mixing circuit.

Claims (1)

[Claims] 1. In a CRT display device in which a personal computer is connected to a television receiver and data images from the personal computer can be simultaneously projected and displayed on a CRT screen by superimposing the television image on the screen, shading is created based on the data output from the personal computer. The apparatus includes means for creating a signal, means for arbitrarily adjusting the magnitude of this shadow signal, and means for mixing this adjusted shadow signal with a television image signal, and the apparatus includes a means for creating a signal, a means for arbitrarily adjusting the magnitude of this shadow signal, and a means for mixing this adjusted shadow signal with a television image signal, and the apparatus includes means for creating a shadow signal on a data image on a CRT screen. The feature is that the contrast of this shading can be adjusted as appropriate.
CRT display device.