JPH0379716B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a color display device used in computer terminal equipment and the like. BACKGROUND OF THE INVENTION In recent years, computers have made remarkable advances in the industrial world, and computer terminal equipment is now displaying multiple colors. For example, color display devices that take 4-bit output from a computer and display 16 colors based on a combination thereof are increasingly being used. An example of a conventional color display device as described above will be described below with reference to the drawings. FIG. 3 shows a conventional color display device. In Figure 3, 1, 2, 3, and 4 are input signals for video display, respectively RED, GREEN, BLUE,
INTENSITY signal (hereinafter R, G, B,
It is abbreviated as I signal. ). 5 is a 16-color display video signal processing circuit unit that creates 16 combinations of video display output signals R ₀ , G ₀ , B ₀ based on the combinations of video display input signals 1 to 4; 6 is for video display; A video amplification circuit 7 amplifies the output signals R ₀ , G ₀ , B ₀ , a color cathode ray tube;
output is connected. 8 is an inverter, 9 is an input signal for video display 1~
This is a circuit that sets the output level to 1/3 according to 4.
The resistance is _R1 . 10 is a circuit that sets the output level of O according to the input signal numbers 1 to 4 for video display, and 11 is a circuit that sets the output level of O according to the input signal numbers 1 to 4 for video display.
This is a circuit that sets the output level of 3, and the resistor is _R2 . 12 are operating resistors R ₃ and R ₄ ;
One end of R ₃ is connected to the operating power supply +E, one end of resistor R ₄ is grounded, and each connection point is connected to the respective terminals of the video display output signals R ₀ , G ₀ , B ₀ . There is. The operation of the color display device configured as described above will be explained below. First, R, G, B, and I signals, which are video display input signals 1 to 4, are input to the 16-color display video signal processing circuit section 5. Next, a circuit 9 in which the signal inverted by the inverter 8 sets an output level of 1/3;
The signal is input to a circuit 10 for setting an output level of 0 and a circuit 11 for setting an output level of 2/3. Now, when 1 is input to the input of the circuit 9 that sets the output level of 1/3, it is inverted by the inverter, the point a becomes O, and the output signal for video display _R0 .
G ₀ and B ₀ are at the level set by R ₁ ×R ₄ /R ₁ +R ₄ /R ₃ +R ₁ ×R ₄ /R ₁ +R ₄ ×E. Next, when 1 is input to all the inputs of the circuit 10 that sets the output level of O, point b becomes O by the NAND gate, and the output signal for video display _R0 .
G ₀ and B ₀ become 0. Next, when 1 is input to the input of the circuit 11 that sets the output level of 2/3, the inverter changes point c to O, and the video display output signals R ₀・G ₀ , B ₀ become R ₂ The level is set by ×R ₄ /R ₂ +R ₄ /R ₃ +R ₂ ×R ₄ /R ₂ +R ₄ ×E. Further, O is applied to the input of the circuit 11 which sets the output level of 0 and 2/3 to one end of the input of the circuit 10 which sets the output level of 0 and 0 to the input of the circuit 9 which sets the output level of 1/3, respectively. When input, the outputs a, b, and c of the inverter and NAND gate become 1,
The video display output signals R ₀ , G ₀ , and B ₀ have levels set by R ₄ /R ₃ +R ₄ (1). Here, when the level of the above formula (1) is set to 1, the combination level of the video display output signals R 0 , G ₀ , B ₀ is set by the combination of the video display input signals R, G, B, _and I. Table 1 shows how this is done.

[Table] Thus, a 16-color image is displayed on the color cathode ray tube 7 by the combination of the image display output signals R ₀ , G ₀ , and B ₀ . Problems to be Solved by the Invention However, in the above configuration, as is clear from Table 2, the input signal for video display, I
When the signal is 0 and at least one of the R, G, and B video display input signals is 1, only 2/3 of the level of the video display output signal is obtained. In general, in the past, short afterglow phosphors were used as the phosphors in cathode ray tubes, so there was no problem with practical brightness even at an output level of 2/3. Due to technical and cost constraints on increasing speed, cathode ray tubes with long afterglow phosphors have come into widespread use. In such a case, a conventional configuration in which only 2/3 of the output level of the video display output signal can be obtained has a problem in that the brightness is insufficient. In view of the above-mentioned problems, the present invention provides an output signal for video display of 1 when the I signal of the video display input signal is 0 and at least one of the R and GB video display input signals is 1. To provide a color display device that can display images with sufficient brightness. Means for Solving the Problems In order to solve the above-mentioned problems, the color display device of the present invention has a color display device in which the I signal of the input signal for video display is 0, and the input signal for video display of R, G, and B is 0. When at least one of these is 1, the output signal for video display is set to level 1, and when the above I signal is 0 and all R, G, and B signals are 1, 2/3 level is output independently. It consists of circuits that are combined to Effects According to the present invention, with the above-described configuration, when the I signal of the video display input signal is 0 and the R, G, and B video display input signals are all not 1, a level of 1 is output. This allows the display to be displayed with sufficient brightness. Embodiment An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a color display device in one embodiment of the present invention. In FIG. 1, 1, 2, 3, and 4 are R, G, B, and I video display input signals, 5 is a 16-color display video signal processing circuit, 6 is a video amplification circuit,
7 is a color cathode ray tube, 8 is an inverter, 9 is 1/3
10 is a circuit for setting an output level of 0, and 12 is an operating resistor, which is the same as the configuration shown in FIG. 2. 13 is a circuit that sets the output level of 2/3, changing from the conventional inverter to a NAND gate,
Further, an AND gate is provided which inputs R, G, and B video display input signals, and the output of the AND gate and the inverted output of the I signal, which is the video display input signal, are added to the input of the NAND gate. This is what I did. The operation of the color display device configured as described above will be explained below. First, R, G, and B signals, which are video display input signals 1 to 3, are sent to a 16-color display video signal processing circuit section 5, which determines the output level of the inverters 8 and 2/3.
It is input to the AND gate of 3. Next, the inverter 8 inverts R.
Circuit 9 sets the output level of G and B signals to 1/3
is input to a circuit 10 which sets an output level of 0. Further, the I signal, which is the input signal 4 for video display, is input to the inverter 8, and the inverted signal is 2/
It is input to the NAND gate of circuit 13 which determines the output level of 3. The output levels of 1/3, 0, 2/3, and 1 are the same as those explained in the conventional example, but the combination of the video display input signals R, G, B, and I increases the video display output signal R. The combinations of output levels of ₀ , G ₀ , and B ₀ are different. Table 2 shows how the combination level of the video display output signals R ₀ , G 0 , and B ₀ is set by the combination of the video display input signals R, G _, B, and I in the embodiment. The combination output level differs from the conventional example in the parts No. 2 to 7 in Table 2. Thus, the above video display output signals _R0・_G0・
A 16-color image is displayed on the color cathode ray tube 7 by the combination of _B0 . As described above, according to this embodiment, as is clear from Table 1, the video display input signals R, G, and B
There is a function to set a level of 1 when there is a function, a function to set a level of 1/3 when there is no video display input signal R, G, B, and a function to set a level of 1/3 when there is no video display input signal I. A function to sometimes set the above 1/3 level to 0 and input signal R for video display.
Since it has a function to set the level to 2/3 when G and B are present and the video display input signal I is not present, the video display input signal R, G,
While ensuring sufficient brightness when B and I are all 1,
When the video display input signal I is 0 and the video display input signals R, G, and B are 1, a level of 1 can be output, so that more sufficient brightness than before can be obtained.

[Table] A second embodiment of the present invention will be described below with reference to the drawings. FIG. 2 shows a color display device according to a second embodiment of the invention. In FIG. 2, numerals 1 to 13 have the same structure as in FIG. 1. The configuration that differs from the one in Figure 1 is the circuit 9 that sets the output level to 1/3, the circuit 10 that sets the output level to 0, and the circuit 1 that sets the output level to 2/3.
The point is that the resistor connected to 3 was changed to a variable resistor. The operation of the color display device configured as described above will be described below. The basic operation is the same as that in FIG. 1, so detailed explanation will be omitted. In Figure 2, compared to Figure 1, the resistor that sets the output level between 0 and 1 is changed to a variable resistor, so the output signal for video display represented by 1/3 and 2/3 is Since the output levels of R ₀ , G ₀ , and B ₀ can be set independently to any value, the input signal I for video display can be set to 0.
, and the input signals R, G, and B for video display are 1 in total.
It is possible to set the output level to any value between 0 and 1 while setting the output level to 1 when the color is not displayed, and it is possible to freely output levels with different color points. As mentioned above, by changing the resistor that sets the output level between 0 and 1 to a variable resistor, 0
The output level between 1 and 1 can be freely set, and different levels of color points can be freely output. Although all the resistors were changed to variable resistors in the second embodiment, it goes without saying that at least one resistor may be changed to a variable resistor or the resistance value of at least one resistor may be changed. Nor. Further, in the first and second embodiments, a cathode ray tube was used as the display medium, but it goes without saying that the present invention can also be used in a color display device using a liquid crystal panel. Effects of the Invention As described above, according to the present invention, the input signal for video display is 0 at I, and the input signal for video display is R.
Since the configuration is such that a level of 1 is output when G and B are not all 1, the brightness when the input signals R, G, B, and I for video display are all 1 is set to sufficient brightness, and the input signal for video display is If the video display input signals R, G, and B are 1 when the signal I is 0, then 1
level, it is possible to obtain more sufficient brightness than in the past.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a color display device according to an embodiment of the present invention, FIG. 2 is a circuit diagram of a color display device according to a second embodiment of the present invention, and FIG. 3 is a circuit diagram of a conventional color display device. It is a diagram. 1, 2, 3, 4...input signal for video display, 5...
...Video signal processing circuit for 16-color display, 6...Video amplification circuit, 7...Color cathode ray tube, 8...Inverter, 9...Circuit for setting 1/3 output level, 1
0...Circuit for setting the output level of 0, 11,1
3...Circuit for setting the output level of 2/3, 12...
...Resistance for operation.

Claims (1)

[Claims] 1. Generates a video display output signal consisting of a combination of the first, second, and third signals in response to the first, second, third, and fourth video display input signals. the circuit, when the first, second, and third video display input signals are present, the first, second, and third video display input signals are present;
a circuit for setting the video display output signal level to a first level; and a circuit for setting the video display output signal level to a first level;
a circuit for setting a third video display output signal level to a second level; and a circuit for setting a third video display output signal level to a second level;
A circuit that sets the second and third video display output signals to a third level, and the first, second, and third video display input signals are present, and a fourth video display input signal is provided. and a circuit for setting the first, second, and third video display output signals to a fourth level when no video display is present. 2. Claim No. 2 characterized in that when the first level is set to 1, the second level is set to 1/3, the third level is set to O, and the fourth level is set to 2/3. Color display device according to item 1. 3 Setting at least one of the first level, second level, third level, and fourth level to a different value for each of the first, second, and third video display output signals. A color display device according to claim 1, characterized in that: