JPS61262787A - Large-scale integrated circuit for crt display - 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 generates a video signal for displaying two numbers, two characters, two figures, etc. on a CRT screen, and outputs these characters in one of seven colors for each character. The present invention relates to a large-scale integrated circuit for CRT display, which is capable of selecting one color from the list and displaying it extremely clearly on a CRT screen.

Conventional technology Conventionally, a single CRT display semiconductor integrated circuit was used to perform CR.
When displaying characters of different colors on the T screen, as shown in FIG. -5, and by control signals 7-9 from the control microcomputer 6,
By turning on and off these AND gates, the color of the character display was changed. In this conventional example, it is impossible to change the color for each character due to limitations in the calculation speed of the microcomputer 6, and generally the limit is to change the color for each field on the screen.

In addition, in the conventional example, when displaying a character superimposed on a TV broadcast image on a CRT screen, if only the character display signal is output on the screen, both TV images overlap the part where the character is displayed. In order to display the characters, flickering occurs due to the movement of both TV images, so in order to prevent this, a method of blanking only the portion of the TV images displayed on the screen where the characters are displayed. was taken. In addition, in order to blank the TV broadcast image in the portion that overlaps with the character on the screen, an OR gate 14 is provided outside the CRT display semiconductor integrated circuit 1 as shown in FIG. Generally, if any of the outputs 3 to 5 is at a high level, the background output 17 for blanking is output.

Problems to be Solved by the Invention However, when characters are displayed using the method shown in FIG. 3, the ND gates 3 to 6 and the OR gate 14 are inevitably mounted separately. However, since the background output signal, like the character display signal, has a high frequency, signal delay due to wiring capacitance becomes a problem that cannot be ignored. That is, as shown in FIG. 4, this signal delay appears on the CRT screen as a misalignment between the character display and the blanked portion of the TV broadcast image. In addition, 'OR' with the large-scale integrated circuit 1 for CRT display.
- Since the gate 14 is on a different chip,
Since it is difficult to match the characteristics of both transistors, they have the disadvantage of being easily affected by temperature changes in the environment in which they are used. Furthermore, there are problems such as an increase in the mounting area due to mounting logic gates in addition to the large-scale integrated circuit for CRT display.

Means for Solving the Problems The present invention is intended to solve the above-mentioned problems, and includes a first memory for storing one screen's worth of display data and screen control data, and a first memory for storing characters such as characters, two figures, etc. A data memory section consisting of a second memory that controls these, a control circuit that controls these, and a CR that outputs data from the data memory section.
It is composed of an output circuit section that outputs T display data and also generates a background output for TV image blanking that is synchronized with this output. This is a large-scale integrated circuit for CRT display, which is capable of blanking both images and is equipped with three character output terminals for CRT display, which can independently control on and off of the character display output.

Effects According to the present invention, since it is possible to perform blanking of both TV images only on the portion where a character output exists on the CRT screen, the same character can be displayed clearly. In addition, since the background output circuit and the character display circuit are configured on the same chip, their characteristics are well matched and stability is good.

Embodiment FIG. 1 is a circuit diagram of an embodiment of the present invention, showing a background output signal output circuit section for blanking a background image only in a portion where a character is superimposed on a CRT screen. In this figure, x, y, and z are character output terminals R and G, respectively.
, B are signals for turning each color signal output on and off independently. By switching these three signals for each character, one color from among seven colors can be selected and displayed for each character. That is, serial character data 27 (VO
W) and color control signals 19, 20, 21 (X, Y.

2) NOR22, 23, 24 are input to DFF 29.30°31 at a display clock of 1 s (HCK), and character display outputs 33, 34, 35 (R, G
, B).

Also, character display output R, G, B (33°s4.s
s) is on, that is, the color control signal 19,
If the output of any one of 20, 21 (X, Y, Z) is low level /I/ (hereinafter abbreviated as -L), the output of the ND gate 25 becomes 'L', so the background output - When the group signal 28 (BLK) is L, NOROR gate 14 character te = l' 27 (VO'W) KaD F
It is input to F 32 as a7i1s (HCK) for display, and becomes the background output as (Y) for blanking the image only in the part where the character is on the screen.

Next, FIG. 2 shows an embodiment of a circuit for blanking the image on the 017 screen using this background output signal 36 (Y). In this figure, image signals 37 and 38.

39 (R, G, B) is the image signal of the TV displayed on the 017 screen, on-screen R, G, B (40, 41
, 42) respectively represent character display outputs of the large-scale integrated circuit for 0CRT display of the present invention. The transistor 50 to which the background output signal 43 (Y) is input in FIG.
(Q7) converts the background output signal 43(Y) from +5V level y to +12V level.

When this signal is ``L'', the controller 51 (QB)
turns on and the output of transistor 51 (QB) becomes L#, so transistors 44, 415°46 (Ql 1Q
31Q5) operates and displays an image on the 017 screen. When the background output 43 (Y) is at high level /L/ (hereinafter abbreviated as H'), the transistor 51 (Qj) is turned off, so that the image is in a blanking state on both screens. At this time, transistors 47, 48, and 49 (Q2, Q4, and Q6) operate, and only the character output is displayed on the 017 screen.

Background output 43 (Y) is character display output 4o/4
If even one of 1.42 (R, G, B) is 1H',
H', the image is blanked only in the part where the character is superimposed on the 017 screen.

Effects of the Invention As described above, according to the present invention, not only can characters be displayed on the 017 screen by selecting one color from seven colors for each character using a single-chip semiconductor integrated circuit, but also characters can be displayed on the 017 screen using one color from the same integrated circuit. By blanking the portion of the image that overlaps the character using the background output, the character can be displayed extremely clearly without being disturbed by the movement of the image. Moreover, since the background output circuit and the character display output circuit are configured on the same semiconductor chip, there is no difference in the temperature environment of the transistors, and the characteristics can be easily matched, which suppresses misalignment between the background output and the character on the screen. This has the effect of reducing the mounting area.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a main part of an embodiment of the present invention, Fig. 2 is a circuit diagram of a CRTR operating part according to an embodiment of the present invention, Fig. 3 is a circuit diagram of a conventional example, and Fig. 4 is a CRT display display according to a conventional example. - Shape the turf. 22～24.26...NOR gate, 26...
...AND gate, 29-32...DFF
, 33, 34° 35... Character output R, G
, B each terminal, 36... Background output terminal. Name of agent: Patent attorney Toshio Nakao and 1 other person 1st
Figure 2 Figure 3

Claims (1)

[Claims] The first one stores display data and screen control data for one screen.
A data memory section consisting of a second memory for storing characters such as letters and figures, and a control circuit for controlling these; and outputting the data output from the data memory section as CRT display data; It also includes an output circuit section that generates a background output for TV image blanking in synchronization with this output, and the background output can blank the TV image only in the portion where character output exists on the CRT screen. A large-scale integrated circuit for a CRT display, further comprising three CRT display character output terminals capable of independently controlling on/off of the character display output.