JPS61290484A - Display unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a display device that displays multivalued images and characters in a superimposed manner on the same screen.

[Conventional technology]

Conventionally, in this type of display device, the gray scale is displayed in a fixed shape at a fixed position on the screen using hard-wired logic.

[Problem that the invention seeks to solve]

Therefore, in such conventional display devices, the shape of the gray scale and its display position are fixed, and when the display contents of one image become diverse, it is impossible to display the optimal gray scale for each image. There were drawbacks.

[Means for solving problems]

According to the present invention, gray scales of different values are defined in advance for each of a plurality of unused character codes, and the character codes are stored at an address in a character memory corresponding to an arbitrary position on the display screen. By extracting the character code as necessary and outputting the corresponding gray scale data from a gray scale generator, a gray scale of any shape can be displayed at any position on the display screen.

That is, in the display device of the present invention, gray scales of different values are defined in advance in correspondence to a plurality of unused character codes, and the character codes are written to addresses corresponding to positions on the display screen in the character memory. and a grayscale generator that inputs a character code output from a character memory and outputs grayscale data corresponding to the character code to a mixer.

〔Example〕

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

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

The display controller 1 inputs image data and controls writing it into the image memory 3, controls writing character data or grayscale data into the character memory 2, and controls the character memory 2 for various displays. The output from the character generator 5 is sent to both the character generator 5 and the gray scale generator 4. General characters are input from the character generator 5 as character dots to the mixer 6, and the gray scale data is converted into multi-tone gray by the gray scale generator 4. It is converted into a scale and input to the mixer 6. The mixer 6 mixes the output from the image memory 3, the output from the grayscale generator 4, and the character generator 5.
The outputs from the D/A converter 7 are mixed and input to the D/A converter 7.

The D/A converter 7 converts the input mixed data into an analog video signal and outputs it.

Table 1 shows an example in which a gray scale is defined as a character code in a display device that displays 256 levels of gray scale.

Here, 33 grayscale level values are assigned to 33 character codes (80)+6 to (9F)+6 and (FF)16, respectively. If you follow this definition, for example, if you write (90) 1G as a character code to the character memory, a gray scale/
l/L/Hell (80L& rectangular gray scale is displayed.

Table 1 [Effects of the Invention] As explained above, the present invention has gray scales of different values defined in advance corresponding to a plurality of unused character codes corresponding to the positions on the display screen of the character memory. By writing to an address and inputting the character code to a grayscale generator to output a grayscale with a specified level value at the position on the display screen corresponding to the address, it is as simple as displaying a character. Through operation, it is possible to display grayscale of any shape at any position on the display screen, and the effect is that the grayscale of the optimal shape and level can be easily displayed at the optimal position for the displayed content of the image. There is.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a display device according to the present invention. 1-m-display controller, 2-m-character memory, 3-
- one image memory, 4-m-grayscale generator, 5-m-character generator. 6-- Mixer, 7-- D/A converter.

Claims (1)

[Claims] A multi-valued image and characters are displayed superimposed on the same screen, comprising a character memory, an image memory, a character generator, and a mixer that mixes the output of the image memory and the output of the character generator. In a display device, gray scales of different values are defined in advance in correspondence with a plurality of unused character codes, and means for writing the character codes to addresses corresponding to positions on the display screen of a character memory; A display device comprising a grayscale generator that receives a character code output from a character memory and outputs grayscale data corresponding to the character code to a mixer.