JPH0253798B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Field of Industrial Application The present invention relates to a color display device, and particularly to a color display device.
This invention relates to a color display device that inputs RGB primary color signals and displays colors. Incidentally, such a device is used as a terminal device such as a personal computer.

(b) Conventional technology Conventionally, as a color display for this type of device,
A system that displays eight colors (including black) by adding RGB primary color signals in binary format has been widely used. Although this color display provides the desired display effect, when using text displays for long periods of time, the eyes may become tired, so it is recommended to switch from color display to a single color, for example, green display. is desirable.

The applicant of the present application previously proposed a color display device in which a color display mode and a single color display mode can be selected in Japanese Patent Application No. 185607/1983.

However, since the single color display mode in the above application is applied to one of the three electrodes of the cathode ray tube corresponding to the three primary colors of RGB, RG.
Only one of the B3 primary colors can be displayed,
For example, it is not possible to display a single color other than the three primary colors, such as amber, which is said to cause relatively little eye fatigue. Moreover, in addition to the single color display function of green, it is desired by users to have a single color display function other than the three primary colors.

(c) Problems to be solved by the invention The present invention has been made in view of the above points,
An object of the present invention is to provide a color display device that can switch display between a single color display mode other than the three primary colors of RGB and a color display mode.

(d) Means for solving the problems The present invention provides a color display mode and a binary RGB3
It has a switching means for selecting a single color display mode that displays a single color other than the primary colors, and RGB output terminals, and when the color display mode is selected by the switching means, the three primary color signals or the composite image The signals obtained by converting the signal into three primary color signals are
output from each of the RGB output terminals, and when the single color display mode is selected, at least one of the three primary color signals or the luminance signal in the composite video signal is weighted at a predetermined ratio and the
It is equipped with an output circuit that outputs from each RGB output terminal.

(e) Effect By the means described above, the present invention can display intermediate colors other than the three primary colors of RGB in the single color display mode.

(F) Embodiment An embodiment of the present invention will be described below with reference to the drawings.

The display color in the single color display mode of this embodiment is amber color, and this amber color is R:G:B
It is obtained by mixing at a ratio of =1:a:0 (a<1). That is, each binary signal may be weighted and added. If you want to get this on screen,
Signals as shown in FIG. 1 or 2 may be applied to the three electrodes corresponding to the three primary colors of RGB of the cathode ray tube. That is, in FIG. 1, by adjusting the amplitude, and in FIG. 2, by adjusting the bottom level of the G signal, R:G:B=
1:a:0.

Next, FIG. 3 shows a circuit diagram of a first embodiment of the present invention. In this embodiment, RGB is input as a binary signal, and when a G signal is input and the changeover switch is switched from color display mode to single color display mode, amber color display is performed.

In the figure, 1, 2, and 3 are the first to third input terminals 4, 4, etc., into which RGB binary signals are input, respectively, are waveform shaping circuits, _S1 is the R input in color display mode, and single color display The first selector switch _S2 selects each G input in the color display mode, and the G input passes through one waveform shaping circuit 4 in the single color display mode, and the G input passes through two waveform shaping circuits in the single color display mode. 4,4
a second selector switch that respectively selects the one that passes through the
S ₃ is connected to ground in color display mode, and connected to the 12V power supply in single color display mode, and is the third changeover switch. S ₄ selects B input in color display mode, and is connected to ground in single color display mode. Fourth
It is a changeover switch.

5, 6, and 7 are first, second, and third terminals that output RGB signals to the corresponding three electrodes of the cathode ray tube, respectively.
This is an output circuit, and the first output circuit includes a first output transistor TR ₁ and resistors R ₁ and R ₂ that set the bias of the transistor. The second output circuit 6 also includes a second output transistor TR ₂ , resistors R ₃ and R ₄ for setting the bias of the transistor, a resistor R ₅ connectable in parallel with the resistor R ₄ , and a connection of the resistor R ₅ .
It consists of a switching transistor _TR4 whose disconnection is controlled by the output of the third changeover switch _S3 . Further, the third output circuit 7 includes a third output transistor TR ₃
and a resistor that sets the bias of the transistor.
It consists of R ₆ and R ₇ . The resistance values of the resistors R ₁ , R ₃ , R ₆ and the resistors R ₂ , R ₄ , R ₇ are set to be equal. That is, the first to third output transistors
The biases of TR ₁ to TR ₃ are the same when the switching transistor TR ₄ is off.

Note that after the G signal input from the second input terminal 2 passes through the waveform shaping circuit 4, the first and second changeover switches
The reason why the waveform shaping circuits 4, 4 are arranged on the paths supplied to S ₁ and S ₂ , respectively, is to achieve impedance matching with the first and second output circuits, respectively.

Next, the operation of the above circuit will be explained.

First, in the color display mode, the first to fourth changeover switches S ₁ to S ₄ fall to the upper contacts in FIG. 3, and input from the first to third input terminals 1 to 3 is
Each RGB input signal is sent to a waveform shaping circuit 4, 4,
4. First, second and fourth changeover switches S ₁ , S ₂ and
_S4 , and then output from the first to third output circuits 5 to 7.

Here, since the third changeover switch _S3 is connected to the ground side, the switching transistor _TR4
is turned off. Therefore, the bias states of the first to third output transistors TR ₁ to TR ₃ are set to be the same, and the DC voltage corresponding to "1" of each input binary signal is constant.

Next, in the single color display mode, the first to fourth changeover switches are turned to their lower contacts.

Then, the G signal input from the second input terminal 2 is 2
It is supplied to the first and third changeover switches S ₁ and S ₃ through the waveform shaping circuits 4 and 4, respectively, and is output as an R output and a G output from the first and second output circuits 5 and 6, respectively. . At this time, the third changeover switch _S3 is
Since it is connected to the 12V power supply, the switching transistor TR ₄ is turned on and the resistor R ₅ is inserted in parallel with R ₄ . Therefore, during the period corresponding to "1" of the input binary signal, the base potential of the second output transistor (TR ₂ ) is lower than that of the first output transistor TR ₁ , so the emitter output is R
The G output is lower than the output (R output:G output=1:a). In addition, “0” of the input binary signal
During the period corresponding to , the base potentials of the first and second output transistors TR ₁ and TR ₂ become approximately ground potential, and both transistors are cut off, so that both emitter outputs are respectively 0V.

On the other hand, since the base of the third output transistor _TR3 is at approximately ground potential regardless of the input signal, the emitter output of this transistor, that is, the B output, is 0V.

Therefore, by inverting each of the RGB outputs weighted as described above using an inverting circuit (not shown), the electrode drive waveform shown in FIG. 1 can be obtained, thereby producing an amber color display.

According to the embodiment described above, when displaying characters, for example, if the background is entirely blue and the character portion is green, only the character portion can be converted to amber color.

Next, another embodiment will be described with reference to FIG.

In this example, in the background part other than text,
If there is no RGB signal, the text will be displayed in amber if any of the RGB input signals is present in the text area.

In the figure, 8 is an OR circuit that takes the logical sum of inputs from the first to third input terminals 1 to 3, S ₁₁ is a first changeover switch that selects the R signal input or the OR circuit output, and S ₁₂ is the G signal A second changeover switch _S13 for selecting the input or the output of the OR circuit is a third changeover switch connected to the B signal input or ground. Reference numeral 9 denotes clamp circuits 5', 6', which DC clamp the outputs of the first to third changeover switches step by step.
Reference numeral 7' indicates first, second, and third output circuits, and the first output circuit is composed of a first output transistor _TR1 and an emitter resistor _R8 . Further, the second output circuit 6' includes a second output transistor TR ₂ and emitter resistors R ₉ and R _{10 .}
and a fourth changeover switch _S14 for selecting the emitter of the second output transistor and the midpoint of connection between the emitter resistors _R9 and _R10 . Also the third
The output circuit 7' is composed of a third output transistor _TR3 and an emitter resistor _R11 . The resistance value of the emitter resistor _R8 , the combined resistance value of _R9 and _R10 , and the resistance value of _R11 are set to be equal.

Further, the first to fourth changeover switches are configured to be switched by movement, respectively.

Next, the operation of the above circuit will be explained.

First, in the color display mode, the first to fourth changeover switches S ₁₁ to _{S 14} are pushed down to their upper contacts, respectively, and the RGB signal inputs from the first and third input terminals 1 to 3 are transferred to the waveform shaping circuits 4 and 4. , 4 and the first to third changeover switches S ₁₁ to S ₁₃ to the clamp circuit 9. Each output clamped here is the first to third output.
It is supplied to each base of output transistors TR ₁ to TR ₃ and output from each emitter. At this time, the fourth changeover switch _S14 is connected to the emitter of the second output transistor _TR2 , so each of the RG and B signal outputs
The DC level becomes the same, and this output is converted into a negative polarity signal by an inverting circuit (not shown) and applied to three electrodes of a cathode ray tube (not shown) to display a predetermined color display.

Next, in the single display mode, the first to fourth changeover switches S ₁₁ to S ₁₄ are respectively switched to the lower contacts. Then, when there is any of the RGB signal inputs, an output appears in the OR circuit 8, and the output is the first
and is selected by the second changeover switches S ₁₁ and S ₁₂ and supplied to the first and second output circuits 5' and 6'. At this time, the fourth changeover switch _S14 is switched to the connection point of the emitter resistors _R9 and _R10 , so R
The DC level of the G output is lower than that of the output.
On the other hand, since the third changeover switch _S13 is connected to ground, the B signal input to the third output circuit 7' is cut off, and the emitter output of the third output transistor _TR3 corresponds to "0" of the R signal output. The DC level is output.

Therefore, by inverting the above three outputs using an inverting circuit and adjusting the DC level, the second
The electrode drive waveform shown in the figure is obtained, and amber color display is possible.

Next, another embodiment will be described with reference to FIG.

This embodiment shows a case where the input signal is a composite video signal, and the demodulated R-Y signal, R-Y signal, and B-Y signal are input to the first to third input terminals 1 to 3, respectively. . 5″, 6″, and 7″ are first, second, and third output circuits, and the first output circuit 5″ is composed of a first output transistor TR ₁ and a load resistor R ₁₂ connected to its collector. . Further, the second output circuit 6'' includes a second output transistor TR ₂ , a load resistor R ₁₃ ,
A switching transistor _TR5 connected between the base and emitter of this second output transistor and a resistor connected between the collector of this switching transistor and the base of the second output transistor.
Consists of R ₁₄ . The third output circuit 7'' is composed of a third output transistor _TR3 , a load resistor _R15 , and a switching transistor _TR6 connected between the base and emitter of the third output transistor. The base of the transistor is biased by a bias circuit (not shown).

(SW) is a changeover switch that is connected to ground in the color display mode and connected to the 12V power supply in the single color display mode, and its output is applied to the bases of the two switching transistors TR ₅ and TR ₆ . Ru.

Further, in the single color display mode, the color signal reproducing circuit (not shown) is configured to stop operating in conjunction with the changeover switch. .about.3, no color difference signal is input to each of them.

Further, a Y signal (luminance signal) is supplied to each emitter of the first to third transistors, and RGB signal outputs are respectively taken out from each collector. Note that each collector resistance has the same value.

Next, the operation of the above circuit will be explained.

First, in the color display mode, the changeover switch (SW) is pushed to the upper contact point, turning off both the switching transistors _TR5 and _TR6 .

Therefore, from the collector of each output transistor
RGB outputs are obtained and applied to each of the three electrodes of the cathode ray tube to produce a color display.

Next, when in single color display mode, the selector switch is
Since SW is connected to the 12V power supply, the switching transistors TR ₅ and TR ₆ are respectively turned on.

Since the operation of the color signal reproducing circuit (not shown) is stopped in conjunction with the changeover switch, the first
~No color difference signals are input to the third input terminals 1-3.

Therefore, the first and second output transistors TR ₁ ,
A Y signal output appears at the collector of TR ₂ , but since a resistor R ₁₄ is inserted between the base and emitter of the second output transistor TR ₂ , the gain of this transistor is smaller than that of the first output transistor TR ₁ . The G signal output is smaller than the R signal output.
Furthermore, the base and emitter of the third output transistor _TR3 are at the same potential and the transistor is turned off, so that no Y signal is output from the collector.

Therefore, each RGB signal output has a waveform as shown in FIG. 1, thereby realizing an amber color display.

(G) Effects of the Invention As described above, according to the present invention, when performing a graphic display, a color display effect can be obtained by setting the color display mode, and when displaying characters, a single color display mode is used. This makes it possible to display a single color other than the RGB three primary colors, such as amber, which causes less eye fatigue, according to the user's preference.

[Brief explanation of drawings]

1 and 2 are explanatory diagrams of electrode application waveforms for amber color display, respectively. FIG. 3 is a circuit diagram of a main part of a color display device according to an embodiment of the present invention. FIG. FIG. 5 is a circuit diagram of the same essential parts in another embodiment of the present invention. 1, 2, 3...first to third input terminals, 5, 5',
5''...First output circuit, 6,6',6''...Second output circuit, 7,7',7''...Third output circuit, _S1 ~
S ₄ , S ₁₁ ~ S ₁₄ ... 1st ~ 4th changeover switch, SW
...Switching switch, TR ₄ , TR ₅ , TR ₆ ...Switching transistor.

Claims (1)

[Claims] 1. Inputting a binary RGB three primary color signal or a composite video signal created based on the three primary color signals,
A color display device for displaying color, comprising a switching means for selecting a color display mode and a single color display mode for displaying a single color other than the three RGB primary colors, and an RGB output terminal, and the switching means selects the color display. When the mode is selected, the three primary color signals or the signals obtained by converting the composite video signal into the three primary color signals are output from the RGB output terminals, and when the single color display mode is selected, the three primary color signals are output. at least one of
or an output circuit that weights a luminance signal in the composite video signal at a predetermined ratio and outputs the weighted signal from each of the RGB output terminals.