JPS6116077B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color display device capable of displaying two or more colors in each display unit of a display screen. Here, the display unit refers to a rectangular pixel that constitutes a display screen. For example, in the case of character display, the display unit is a display portion of one character.

First, the principle of superposition will be explained. FIG. 1 is a display example, and A in FIG. 1 is a superimposed view of B, C, and D in the same figure. It is a diagram in which a train 12 is superimposed on a track 11, and a train number 13 is superimposed on it. The color of the overlapping part should remain the same as the color of the higher priority pattern, and should not be mixed. Note that in FIG. 1, C is higher than B, and D is higher than C.

FIG. 2 is an example of a conventional color display device.
This figure is a block diagram of a color display device that superimposes two types of patterns. Display codes 21 and 22 sent from the controller of the color display device are stored in refresh memories 23 and 24.
Display codes 21 and 22 are decomposed into color information 25 and 26 and character symbol codes 27 and 28,
Color information 25 and 26 are sent to color flip-flops 29 and 30 and held until the next color information arrives. The character symbol codes 27 and 28 are sent to character symbol pattern generators 31 and 32;
It is converted into character symbol patterns 33 and 34 and sent to character symbol signal generators 35 and 36. The character symbol signal generators 35 and 36 perform parallel-to-serial conversion of the character symbol patterns 33 and 34 inputted as parallel signals, produce character symbol signals 37 and 38, and send them to the color controllers 39 and 40. Color controllers 39 and 40 AND the color flip-flop outputs 40 and 42 with character symbol signals 37 and 38 and send color signals 43 and 44 to priority combining circuit 45. The priority synthesis circuit 45 synthesizes the color signal 44, which has higher priority, so as to display it preferentially, and sends the display signal 46 to the display tube 47 for display. In this way, overlapping display was performed. When performing high-density display or large-capacity display, since a large amount of information is displayed per fixed time, the operating speed becomes 2 to 6 times faster than the conventional display. As a result, the priority combining circuit 45 could no longer follow the high operating speed.

In order to solve this problem, the present invention installs a priority circuit in front of the character/symbol signal generator, and will be described below with reference to FIGS. 3 and 4.

FIG. 3 is an embodiment of the present invention, and is a block diagram of a display device that superimposes two types of patterns. The priority combining circuit 45 in FIG. 2 is divided into priority circuits 51 and 52 and a combining circuit 53, and the priority circuit 51
and 52 are installed in front of the character/symbol signal generators 35 and 36, and the synthesis circuit 53 is replaced with the priority synthesis circuit 45. Here, the priority circuit 52 is the priority circuit 51
Higher priority. The inputs of the conventional priority combining circuit 45 are the color signals 43 and 44, which are serial signals, but the inputs of the priority circuits 51 and 52 are the character symbol patterns 33 and 34, which are parallel signals. If the bit width of the parallel signal is N, converting it to a serial signal will result in a frequency N times higher. Therefore, the inputs to the priority circuits 51 and 52 are the character symbol patterns 33 and 34 of the parallel signals, and the operating speed of the priority circuits 51 and 52 can be reduced.

FIG. 4 shows an embodiment of the priority circuits 51 and 52 shown in FIG. In the figure, 511 and 512 are AND gates, and 513 is an inversion gate. In the priority circuit 51, the upper priority circuit is the priority circuit 52, and there is no lower priority circuit. The priority circuit 52 has no upper priority circuit,
If there is no upper priority circuit whose lower priority circuit is the priority circuit 51, the valid signals 610 to 612 inputted from the upper priority circuit are at a significant level (high potential in this figure). Bit 1 (330) of the character symbol pattern is logically ANDed with the valid signal 610 input from the upper priority circuit and is output as the priority circuit output 6.
00 and is sent to the character symbol signal generator 35. Further, the valid signal 610 of bit 1 inputted from the upper priority circuit is ANDed with the inverted signal of bit 1 (330) of the character symbol pattern 33, and outputted as the valid signal 620 to the lower priority circuit. That is, when the character/symbol signal pattern 33 is at the significant level, it operates to inhibit the corresponding bit of the lower priority circuit.

Although the case where two types of patterns are superimposed and displayed has been described above, the refresh memory 2, character/symbol pattern generator 32, color flip-flop 30, and priority circuit 5 in FIG.
By adding a block consisting of 2, a character/symbol signal generator 36, and a color controller 40, it is possible to display three or more types of patterns in a superimposed manner.

As described above, according to the present invention, since the operating speed of the priority circuit can be lowered, it is possible to easily realize high-density and large-capacity display compared to the conventional art.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a display example to explain the principle of overlapping display, FIG. 2 is a configuration diagram of a conventional color display device, FIG. 3 is a configuration diagram of a color display device in which the present invention is implemented, and FIG. FIG. 4 is a circuit diagram of an embodiment of the priority circuit. In the figure, 23, 24 are refresh memories, 29,
30 is a color flip-flop, 31 and 32 are character symbol pattern generators, 35 and 36 are character symbol signal generators, 39 and 40 are color controllers, 47 is a display tube, 51 and 52 are priority circuits, and 53 is a It is a synthetic circuit. In addition, the same reference numerals are given to the same or corresponding parts in the figures.

Claims (1)

[Claims] 1. In a raster scan color display device that displays arbitrary patterns in combination or overlapping, N refresh memories (N
>1) has N pattern generators that store patterns corresponding to character symbol codes and generate character symbol patterns corresponding to the character symbol codes read from the refresh memory as parallel signals; N character/symbol signal generators that convert character/symbol patterns from parallel to serial to generate serial character/symbol signals, and an output from each pattern generator is provided between each of the pattern generators and the character/symbol signal generator. 1. A color display device characterized in that a priority circuit is provided for passing bits of higher priority among the character symbol patterns according to a predetermined priority order among the character symbol patterns.