JP2000305545A - Image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To give variation to image quality, when a television image is displayed on a CRT for a personal computer. SOLUTION: A table 31 for an image converts image data 102 into data for a television image 103, and a table 32 for a personal computer converts the image data 102 into data for a personal computer 104. On the table 32 for the personal computer, a pallet constant for converting its input into an output is set less than one, and hereby brightness of the data 104 is set relatively lower than brightness of the data 103. A graphics controller 1 provides the table 31 for the image and the table 32 for the personal computer with data in a frame buffer 2, and discriminates the kind of the data. A selector 33 switches the table 31 for the image and the table 32 for the personal computer by an indication from the graphics controller 1 and selects either of the two.

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, and more particularly to an image display device of a personal computer device capable of displaying television images.

[0002]

2. Description of the Related Art In recent years, a multimedia type image display device capable of displaying both a television image and a personal computer image has attracted attention. For example, Japanese Unexamined Patent Publication No. Hei 9-182003 discloses that a display unit having a larger number of pixels than an input image information signal is used, the input image information signal is converted into a signal format corresponding to the display unit, and the display unit outputs an image. An image display device for displaying is described.

The image display device will be described with reference to FIG. 4 showing one embodiment. The display means 17 is, for example, XG
A (eXtended Graphics Array) compatible TFT (Thin Film Tran
(sistor) It is of high image quality like a liquid crystal panel. From the input terminal 11, NTSC (National Television System Co.)
mmittee) TV signal is received and NTSC-VGA (Video
The image data is converted into a VGA signal format video signal by a graphics array (converting circuit) 14. Further, from the input terminal 2, an image information signal of a signal format such as VGA, SVGA (Super VGA), XGA or the like from a personal computer is input, and a switch 15 outputs a video signal of a VGA signal format from an NTSC-VGA conversion circuit 14. Switching is selected.

The output signal of the switch 15 is converted into an image signal of the XGA signal format by a VGA-XGA conversion circuit 16 and supplied to a display means 17. Thus, the input terminals 11, 1
All the image signals input from 2 are displayed on the display means 17 with the number of pixels corresponding to XGA (1024 × 768).

[0005]

However, in the above-mentioned conventional technique, an image of a personal computer and a television image can be displayed on the same display device, but a CRT (Cathod) used in the personal computer is used.
(e-Ray Tube) The brightness of the device is a CRT for general television.
The device has different characteristics such as γ (gamma). For this reason, even if an image made for display on a general television CRT device is displayed on a CRT device used in a personal computer, the image cannot be displayed correctly and the image is not sharp. There is a problem that it becomes.

SUMMARY OF THE INVENTION An object of the present invention is to provide an image display apparatus for displaying an image for television on a CRT device for a personal computer with a sharp image quality.

[0007]

According to a first aspect of the present invention, there is provided an image display apparatus which converts input data into data which conforms to the characteristics of the input data, and judges a type of the input data. Control means for supplying the input data to the conversion means, and switching means for switching the conversion means in accordance with an instruction from the control means and selecting one of the conversion means, and outputting the output of the switching means by the same display means. It is characterized by displaying.

According to a second aspect of the present invention, there is provided an image display device for converting input data into television video data, a personal computer table for converting the input data into personal computer data, and a frame. The data in the buffer is supplied to the video table and the personal computer table, and the graphics controller for determining the type of the data, and the video table and the personal computer table are instructed by the graphics controller. And a switch for selecting either one of the switches. The output of the switch is displayed on the same display.

According to a third aspect of the present invention, there is provided an image display apparatus for converting an input data into a personal computer data, and a video for amplifying an output of the personal computer table into television video data. An amplifier, an amplifier for a personal computer for amplifying the output of the table for the personal computer into data for a personal computer, and graphics for supplying data in a frame buffer to the table for the personal computer and determining the type of the data A controller for switching between the video amplifier and the personal computer amplifier in accordance with an instruction from the graphics controller, and selecting one of the amplifiers. The output of the switch can be displayed on the same display. The features.

In the present invention, the video data for television and the image data of a personal computer have characteristics suitable for each. For this reason, even a CRT for a personal computer can correctly display video data for television. In addition, by lowering the brightness of only the image data of the personal computer, the display of the television image data can be apparently displayed brightly, and a reduced image can be displayed.

[0011]

Next, embodiments of the present invention will be described in detail with reference to the drawings.

Referring to FIG. 1 showing an embodiment of the present invention, a graphics controller 1 reads out image data from a frame buffer 2 to display a screen.
AMDAC (Random Access Memory-Digital Analog Conver
tor) 3. The RAMDAC 3 stores the image data 102 in the video table 31 and the PC (Personal Computer) table 3.
2 to obtain conversion data 103 and 104.

The switch 33 selects one of the conversion data 103 and 104 and inputs it to a DAC (Digital Analog Converter) 34. The DAC 34 converts the selection signal 105 into an analog signal 106 and outputs it to the CRT.

Next, the operation of the present embodiment will be described with reference to the drawings.

Generally, a CR from a personal computer is used.
The output to the T device is performed by the graphics controller sequentially reading out the image data stored in the frame buffer and converting it into an analog signal.
The image data is usually composed of three types of signals of RGB (Red, Green, Blue), but here, since the same processing is performed for all three types, in the following description, only one type of data will be described. Actually, three types of RGB are required.

In FIG. 1, a graphics controller 1 reads out image data 101 from a frame buffer 2 for screen display and inputs it to a RAMDAC 3. In the RAMDAC 3, the image data 102 is input to the video table 31 and the PC table 32.

The video table 31 is a table for television video, and when input is X and output is Y, Y = MM (X / M) γ. Here, M is the maximum value that can be represented by the bits that constitute the input X and the output Y. In the case of 8 bits, M = 255
Becomes Γ is the gamma value of the television, NT
In the case of SC, γ = 2.2.

On the other hand, the PC table 32 is a table for pallet data for a PC screen. When there is no pallet, usually, if the input is X and the output is Y, Y = X. Then, a constant a is prepared and Y = a · X. Here, a is 0 <a <1, and for example, by setting a = 0.7, the brightness of the image data of the personal computer can be reduced.

The switch 33 switches between the conversion data 103 output from the video table 31 and the conversion data 104 output from the PC table 32. The switch 33 outputs the conversion data 104 if the current data is a screen of a personal computer, and the conversion data 104 if the data is a television image embedded in the screen of the personal computer.
103 is selected and output as selection data 105.

The DAC 34 has a selection data 1 which is a digital signal.
05 is converted to an analog signal 106 that can be received by the CRT. As a result, it is possible to perform a gamma correction for only the television image correctly, and to provide a display that is apparently higher in brightness than the personal computer screen and has a sharp appearance.

Next, a description will be given of a method in which the switching unit 33 determines whether to switch the conversion data 103 and 104.

Normally, when a television picture is fitted on a personal computer screen, it is superimposed on a rectangular area as shown in FIG. Here, since the graphics controller 1 knows which part of the data on the screen is currently being read from the frame buffer 2, FIG.
By setting the values of (x1, y1) and (x2, y2), the switch 33 can easily determine the television image area.

When the television screen is displayed on the entire screen, the switch 33 may always select the conversion data 103.

Next, another embodiment of the present invention will be described with reference to FIG. 3 and FIG. 1, the same components are denoted by the same reference numerals.

Referring to FIG. 3, the PC table 32 in the RAMDAC 3 is a pallet table. When the pallet is not used, if the input is X and the output is Y, Y = X. The DAC 32 converts image data 107, which is a digital signal, into an image signal 108, which is an analog signal. The video amplifier 35 is a television video amplifier,
Assuming that X is Y and output is Y, it has the characteristic of Y = MM (X / M) γ Here, M is input X and output
This is the maximum value that can be represented by the bits that make up Y.

The PC amplifier 36 is an amplifier for an image of a personal computer and has a characteristic of Y = a · X, where X is an input, Y is an output, and a constant is a. Here, a is such that a is 0 <a <1. For example, by setting a = 0.7, the brightness of image data of a personal computer can be reduced.

The switch 37 switches between the image signals 109 and 110 and sends the analog signal 106 to the CRT device. The switch 37 is an image signal if the current image signal is video data for television.
109, and the image signal 110 for image data of a personal computer.

As a result, the γ-correction can be correctly performed only for the television image, and the display can be displayed with a higher apparent brightness than the personal computer screen.

[0029]

A first effect of the present invention is that the characteristics of video data for television can be correctly output, and therefore, a natural display can be performed even in a CRT device for a personal computer. The reason is that a table for video data for television is provided separately from the image data for the personal computer.

The second effect is that apparently only the video data for television can have a higher luminance.
For this reason, it is possible to display television video data with a sharp display. The reason is,
This is because the brightness of the image data of the personal computer is slightly reduced.

[Brief description of the drawings]

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

FIG. 2 is a diagram for explaining an operation of a part of FIG. 1;

FIG. 3 is a block diagram of another embodiment of the present invention.

FIG. 4 is a diagram showing an example of a conventional technique.

[Explanation of symbols]

 1 Graphics controller 2 Frame buffer 3 RAMDAC 31 Video table 32 PC table 33 Switch 34 DAC 35 Video amplifier 36 PC amplifier 37 Switch 101 Image data 102 Image data 103 Conversion data 104 Conversion data 105 Selection signal 106 Analog Signal 107 Image data 108 Image signal 109 Image signal 110 Image signal

Claims (6)

[Claims] A conversion unit for converting the input data into data that matches characteristics of the input data; a control unit for determining a type of the input data and supplying the input data to the conversion unit; Switching means for switching the conversion means in response to an instruction from the control means, and selecting one of the conversion means, wherein the output of the switching means is displayed on the same display means. 2. A video table for converting input data into television video data; a personal computer table for converting the input data into personal computer data; and a video table using data in a frame buffer. And to the personal computer table,
A graphics controller for determining the type of the data; and a switch for switching between the video table and the personal computer table according to an instruction from the graphics controller, and selecting one of the tables. An image display device for displaying on the same display. 3. A table for a personal computer for converting input data into data for a personal computer; a video amplifier for amplifying an output of the table for the personal computer to data for television video; An amplifier for a personal computer for amplifying an output to data for a personal computer; a graphics controller for supplying data in a frame buffer to the table for the personal computer, and determining a type of the data; An image display device comprising: a switch for switching between the video amplifier and the personal computer amplifier according to an instruction and selecting one of the amplifiers, and displaying the output of the switch on the same display. 4. The image display apparatus according to claim 2, wherein a pallet constant for converting an input into an output of the personal computer table is set to less than 1. 5. The image display device according to claim 3, wherein the amplification degree of the personal computer amplifier is set to less than 1. 6. When a television image is fitted to a personal computer screen, the graphic controller issues a switching instruction to the switch by detecting an area occupied by the television image in the frame buffer. 4. The image display device according to claim 2, wherein: