JPS643273B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is capable of dividing one screen into multiple parts in an arbitrary shape, displaying a mixture of images with different properties, and displaying images of various colors with a small memory capacity. The present invention relates to an image display device capable of displaying images.

Conventionally, the following two methods have been mainly used to simultaneously display a plurality of pieces of information with different properties, for example, black and white characters and colored figures, on one screen.

FIG. 1 shows an example of the configuration of a conventional image display device according to the first method. 1, 2, and 3 are image memories, and 4 is a synthesis circuit. Different memories 1, 2, and 3 are used for each piece of information. The synthesizer circuit 4 synthesizes these signals and displays them in a superimposed manner. This method uses, for example, 1 bit/pixel memory for characters and 3 bits/pixel memory for graphics.
Since a bit/pixel memory is used, it is always necessary to have a 4 bit/pixel memory.

Figure 2 shows an example of the configuration of a conventional pixel display device using the second method, in which one memory is divided into upper and lower parts, the upper part 5 is used as a character area to write characters, and the lower part 6 is used as a graphic area. This is a method of writing shapes. When displaying an image, the presence or absence of color is switched by a switching signal generated from a signal generating circuit outside the memory. However, this method has the drawback that in order to simplify the signal generation circuit, only simple divisions such as vertical, horizontal, etc. are possible.

Figure 3 shows a configuration example of a conventional color conversion circuit used to display a variety of colors with a small memory capacity.The color code input 7 is decoded by a decoder 8 to output a red signal 9, a green signal, and a green signal. Signal output 10, green signal output 11
However, in the past, one circuit was fixedly connected to one memory, and in order to change the combination of colors to be displayed, it was necessary to replace the memory table in the color conversion circuit. .

In order to eliminate these drawbacks, the present invention provides a control bit for each pixel of the memory, changes the usage of the memory by referring to this control bit, and connects multiple color conversion circuits and memory outputs. A switch is provided in between to make the connection between each bit of the memory and the input of the color conversion circuit variable, and will be explained in detail below with reference to the drawings.

FIG. 4 is a configuration diagram showing an example of allocation of the contents of one address of the image memory used in the present invention.
12 is a control bit, and the other part 13 is an image bit indicating image data. For example, a binary number indicating the method of dividing the image bits is written into the control bit 12.

FIG. 5 shows an example of the division of image bits. A is a high-resolution display mode, and each bit of A, B, C, and D has the positional relationship shown in FIG. 6 on the screen. In this mode, the number of dots per pixel is small, but one memory address stores information for four pixels. B is a natural image display mode, in which information for one pixel (red component R, green component G, blue component B) is stored at one memory address. C is a multi-frame display mode, in which one memory address also corresponds to one pixel, but multiple images can be switched or displayed in a superimposed manner as in F1 to F4. For example, characters or the like can be displayed superimposed on a background image. In this way, when only characters are to be rewritten, only the character information needs to be provided, and there is no need to rewrite the background information.

FIG. 6 shows an example of pixel arrangement in the high resolution display mode, where 14 indicates a high resolution pixel and 15 indicates a standard resolution pixel.

The first feature of the present invention is that the various display modes described above can coexist on one memory, and furthermore, the control bits 12 are set for each memory address.
Since this is added, a display mode area of any shape can be realized in units of one memory address.

FIG. 7 shows an example of the display screen configuration according to the present invention, in which 16 is a high-resolution area, 17 is a natural image area, 18 is a multi-frame area, and 1
9 and 20 indicate, for example, a figure written in the first frame and a figure written in the second frame.

According to the present invention, by referring to the control bits 12 when sequentially reading out the memory for display, it is possible to easily know which display mode the content of the address is in. It is possible to easily display an image in a complex-shaped display mode area.

The second feature of the present invention is that it enables correspondence between color conversion circuits and image bits.

FIG. 8 shows an example of the configuration of a color conversion circuit used in the present invention. Reference numeral 21 indicates an image memory, 22 indicates a changeover switch, and 23 indicates a color conversion circuit. Since a changeover switch 22 is provided between a plurality of color conversion circuits 23 so that the connection relationship can be changed, if the color combinations of each color conversion circuit are made different, the corresponding color can be achieved simply by changing the connection. It is possible to change the color combination of a frame (a group of divided image bits), and for example, it is possible to instantly change the color of characters, figures, etc. displayed on the screen.

Note that the memory table of the color conversion circuit is 192 bits at most in the case of 8 colors (8 bits each of red, green, and blue output).
Therefore, having more than one of these is not an economic burden.

As explained above, according to the present invention, one screen is divided into a plurality of parts in an arbitrary shape using the control bit 12, and images with different properties, such as high-resolution characters and figures, and multicolored multicolored Natural images with gradations can be displayed in a mixed manner without increasing memory capacity, and since the correspondence between image bits and color conversion circuits can be changed, images with a variety of colors can be displayed with a small memory capacity. There are advantages.

[Brief explanation of drawings]

1 and 2 are diagrams showing an example of the configuration of a conventional image display device, FIG. 3 is a diagram showing an example of the configuration of a conventional color conversion circuit, and FIG. 4 is a diagram showing an example of the configuration of an image memory used in the present invention. 5 is a diagram showing an example of dividing image bits used in the present invention, FIG. 6 is a diagram showing an example of pixel arrangement in high resolution display mode, FIG. 7 is a diagram showing an example of the display screen configuration according to the present invention, and FIG. The figure is a diagram showing an example of the configuration of a color conversion circuit used in the present invention. 1, 2, 3...Image memory, 4...Signal synthesis circuit, 5...Character area, 6...Graphic area, 7...
...Color code input, 8...Decoder, 9...Red signal output, 10...Green signal output, 11...Blue signal output,
12...Control bit, 13...Image bit, 14
...High resolution pixel, 15...Standard resolution pixel, 1
6...High resolution area, 17...Natural image area,
18... Multi-frame area, 19... Figure written in the first frame, 20... Figure written in the second frame, 21... Image memory, 22...
...Selector switch, 23...Color conversion circuit.

Claims (1)

[Claims] 1. In a device that repeatedly reads data stored in an image memory for storing image signals and displays an image on a display device, one or more control bits correspond one-to-one to each memory address of the image memory. The control bit specifies the division method or usage type of bits other than the control bit belonging to the address, and converts the image memory output group and color code input into an output signal corresponding to the display color based on the specification. An image display device characterized in that it is configured such that a color conversion circuit group consisting of a plurality of color conversion circuits can be connected in any combination.