JPS6047584A - Color temperature controller - Google Patents

Abstract

PURPOSE:To control the gain of a control circuit for each color signal and control the color temperature of a TV image receiving tube easily by providing a circuit which controls the gains of the output circuits which drives a TV image receiving tube. CONSTITUTION:A microcomputer 31 discriminates on the operation key 32 of the TV receiver or a signal from a remote control transmitter 33 to control a storage element 35, channel selecting circuit 36, digital signal processing circuit 39, etc. A video and a sound signal from an intermediate frequency amplifying circuit 38 is applied to the circuit 39, which inputs the processed video and sound signals to a color output circuit 40 and a sound output circuit 43 respectively. Respective D/A converters of this circuit 40 convert the video signal into analog signals of three colors, which are applied to amplifying circuits. Further, a gain control voltage is applied from the computer 31 to each amplifying circuit to controls the gain of each color, and applied to the driving circuit which drives the image receiving tube 42, whose color temperature is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a color temperature control device for a picture tube of a television receiver.

Conventional configuration and its problems FIG. 1 shows an example of an output circuit of a conventional picture tube.

In the figure, 1, 2.3 are color difference signals, 4 is a luminance signal, and 5.
6.7 is a drive transistor, 8, 9.10 is a gain adjustment volume, 11.12.13 is a picture tube cutoff adjustment volume, 14, 15, 16° 17.18.19 is a load resistor, 2o is an image receiver tube, 21.22.23 is the picture tube grid voltage generation circuit 24.25 is the power supply, 26, 27.28
are cathode signals for each color. The operation of adjusting the white balance of the picture tube 20 in this output circuit will be described below. When you want to project white on a picture tube, white balance adjustment is performed using polyurethane 11, 12. 13 to adjust the D level of each color offset, and adjust the gain of each color signal by setting the volume to 8, 9, and 10. FIG. 2a is a characteristic diagram of the grid cathode tube voltage (G-) and the beam current IB for each color signal R, G, and B of the picture tube. Note that R is red, G is green,
B represents blue. Now, in FIG. 2, at a point A where the beam current is relatively small, the DC level is adjusted to one point using the volume controllers 11, 12, and 13, and the beam currents are adjusted. Furthermore, point B where the beam current is relatively high
, adjust the gain with the volume 8, 9.10,
The beam current characteristics are adjusted as shown in FIG. 2C.

Although the light emission state and the beam current do not necessarily match, in reality, the color temperature on the surface of the picture tube is measured and the white balance is adjusted. As shown in FIG. 1, once the white balance is adjusted using the volume, it is necessary to turn the volume to change all the operating points, which requires considerable effort. Next, let us consider the case where we try to adjust the color temperature. The color temperature is determined by the cathode signal 26°27.28 in FIG. Generally speaking, changing the color signal with the white balance adjusted means changing the gain, changing the cathode voltages 26, 27, 28 of the picture tube, and changing the beam current, as shown in Figure 3. To do something. For example, as shown in Figure 3a, if you increase the blue gain of B and decrease the red gain of H to make it look bluer, white characters will appear whiter. The result is a beautiful image.

Further, as shown in FIG. 3, by increasing the red gain of H and decreasing the blue gain of B, the image will appear warmer. By changing the color temperature in this way, it is possible to obtain an image that is optimal for the display content. However, in the conventional output circuit, once the white balance is achieved, it is necessary to adjust the volumes 8, 9, and 10 in order to change the color temperature, and an adjustment jig is also required, which requires a lot of effort.

OBJECTS OF THE INVENTION The present invention is intended to solve the above-mentioned conventional problems, and it is an object of the present invention to provide a device that can easily control the color temperature of a picture tube.

Structure of the Invention The color temperature control system R according to the present invention includes a picture tube, an output circuit for driving the picture tube, and a circuit for controlling the gain of the output circuit. By controlling the color temperature, the color temperature can be completely controlled.

Description of Embodiments In recent years, in television receivers, devices such as microcomputers and digital signal processing circuits that process or control television signals using digital data have been developed. FIG. 4 shows a basic digital signal processing television receiver. In Figure 4, 3
1 is a control microcomputer, 32 is an operation key, 3
3 is a remote control transmitter, 34 is a remote control signal receiving circuit, 3
6 is a memory element, 36 is a tuning circuit, 37 is a tuner, 38
39 is an intermediate frequency amplification circuit, 4 is a digital signal processing circuit, and 4 is an intermediate frequency amplification circuit.
0 is a color output circuit, 41 is a drive circuit, page 426 is a picture tube, 43 is an audio output circuit, and 44 is an audio output device.

The basic operation of FIG. 4 will be explained below.

The control microcomputer 31 determines the operation based on the signal from the operation key 32 or the remote control transmitter 33, and stores the memory element 369, channel selection circuit 36. Controls the signal processing circuit 39 and the like. Tuning data and data that serve as initial values for signal processing are stored in the memory element 36, and can be read out and written as appropriate.First, when a tuning operation is performed, the tuning When the circuit 36 operates and drives the tuner 37, the video image obtained there is transmitted through the intermediate frequency amplification circuit 38.
The audio signal is sent to the digital signal processing circuit 39. The digital signal processing circuit 39Fi converts the input signal into a digital signal, performs video/audio signal processing, performs various controls according to commands from the control microcomputer 31, and applies a color signal 46 to the color output circuit 40. This color output circuit 4
o can adjust the DC level and gain of the color signal using digital data 46 from the control microcomputer 31. The signal adjusted here is sent to the drive circuit 41.
is added to drive the picture tube 42. On the other hand, the audio signal 47
is applied to the audio output circuit 43 to drive the audio output device 44.

Now, in FIG. 4, color temperature control is performed by determining a color temperature switching command from the operation key 32 or remote control transmitter 33 by the control microcomputer 31, and then changing the color temperature to the memory element 3.
This is done by reading out the gain control data of the color output circuit 40 stored in the color temperature control data n and 6, and sending the result of calculation with the color temperature control data to the color output circuit 4o to change the gain of the color output circuit 4o.

In the circuit of FIG. 4, a specific circuit for color temperature control of the present invention is shown in FIG. FIG. 6 shows the color output circuit 40. Drive circuit 41
．． This shows the picture tube 42 taken out.

In FIG. 6, 4o is a color signal output circuit, 41 is a picture tube drive circuit, and 42 is a picture tube. 51゜52, 53 is a D/A converter that converts the three color output digital data processed by the digital signal processing circuit 39 in Fig. 4 into analog voltage, and 54, 56゜66 is an amplifier circuit that amplifies the color signal. ,
57, 58.

59 is a picture tube drive circuit, 60, 61, 62 is a picture tube cathode voltage, 63, 64, 65 is an amplifier circuit 54.55.6
The DC level adjustment voltage 66°67.68 is the gain adjustment voltage of the amplifier circuit 54, 65, 56.

1. Let us consider the case where the white balance is adjusted in the color signal output circuit 40 and drive circuit 41 shown in FIG.

The color signal data is sent to the D/A converter 61゜52.53.
The signal is converted to an analog signal and applied to an amplifier 64°56.56. Amplifiers 54, 55, 56 control voltages 63, 64 .
The DC level of the signal is adjusted by 66, and the control voltage 6
The gain is adjusted by 6.67.68. Therefore, as shown in the conventional example, the white balance is adjusted by adjusting the DC level and gain of each color signal in the amplifiers 54, 55, and 66.

The output of this amplifier 54, 55, 56 is the drive circuit 57.5
8.69 to drive the picture tube 42.

Next, color temperature control according to the present invention will be explained.

In Figure 5, signals 60, 61, and 62 are marked red, respectively.
Assuming ER, EG, and EB as green and blue color signals,
Color temperature T can be expressed using a certain function F as follows.

T=F(ER, Eo, EB) =.-(1) The color temperature T is determined by the ratio of the cathode voltage of the picture tube 42. After adjusting the white balance of the picture tube 42, the color temperature is set to T. Then, 7o==F("o"R+', β
. It is expressed as 3+b, roEB+c)-12-(2). Here, %”tβ r is white oot.

This is the gain when the balance is adjusted, a, b.

Similarly, C is the DC level when the white balance is adjusted. As an example of color temperature control, consider a method of changing the gain of each color output. The color temperature TR when lowering the color temperature, that is, when making it reddish, is: 107, -zoTR=F (a 1ER, β1EG, rlEB)
・・・・・・ (Represented by 3, basically 1α11)
1ao1, the color temperature can be lowered as shown in FIG. The color temperature TB when the color temperature is set high, that is, when the color temperature becomes bluish, is T B
= F (a2ER, β2EG?r2”B) --(
4), basically l r 2 + > l r
o l , the color temperature can be increased as shown in FIG. 3a.

Next, FIG. 6 shows an example of a specific gain control method for completely changing the color temperature. FIG. 6 shows a specific example of one of the amplifier circuits 54, 55, and 56 shown in FIG. 6th
In the figure, 71 is a color signal, 72 is an amplifier circuit, 73 is a color output signal, 74 is a DC level adjustment voltage, 76 is a gain adjustment voltage, 76.77 is a D/A converter, 78.79 is a data register, 80 .81 is digital data for control, 82 is a functional block of the control microcomputer 31, 83 is an arithmetic circuit, 84 is a memory data reading circuit, 86 is a color temperature switching circuit, 86 is a color temperature switching signal, 87
indicates a functional block of the memory element 36, 88 is gain data when white balance is adjusted, 89.90 is data for changing color temperature, and 91 is DC level data when white balance is adjusted.

The operation will be explained below with reference to FIG.

First, consider outputting a color signal in a state where the white balance is adjusted. As gain data in the memory 87,
39 σ. ,β. , ro, and 91 a, b, and c are stored as DC level data. These data are read out by the memory data reading circuit 84 of the control microcomputer 82 corresponding to 31 in FIG.
It is applied to the data register 79 as fi, D/A converted by the D/A converter 77, and applied to the amplifier circuit 72 as a gain control voltage 77 to adjust the gain of the color signal.

The level data 91 is added to the register 78 and D/
The signal is D/A converted by the A converter γ6 and applied to the amplifier circuit 72 as a DC level control voltage 74 to adjust the DC level of the color signal and maintain white balance.

Thus, in the present invention, the gain and DC level of the color output circuit 40 can be controlled by digital data. The data can also be stored in memory 87.35.

Next, consider the case of switching the color temperature. For example, when a command to display the color temperature is input from 86, the control microcomputer 82 determines this, drives the color temperature switching circuit 86, and tells the memory data reading circuit 84 to display the color temperature in the memory 87. It works to read the data 89 of 1°°. The read data 89 (σ1.β1.r1) is white balanced data σ. ,β. , ro are calculated by the calculation circuit 83 and sent to the data register 79 as gain data 81 with a lower color temperature to control the gain control voltage 76. If the color temperature is to be increased further, the data 9o of the color temperature parameter 2'' is read out from the memory 87 and the data 9 for controlling the entire gain is sent 9 to control the gain of the amplifier circuit 72 in the same manner as above.

13,...

As described above, in this embodiment, the DC level and gain of each color signal can be adjusted using digital data. Therefore, in order to control the color temperature, it is only necessary to change the value of the gain data, and any color temperature setting can be made. It becomes possible. In FIG. 6, the color temperature data 89 and 90 in the memory 87 may be fixed values, or may be calculated and output directly as gain data.

Effects of the Invention As described above, according to the present invention, in a digital signal processing circuit that can control the DC level and gain of a color output circuit using digital data, white balance adjusted data is stored in a storage element as a standard value. By calculating the standard data and the second data according to a color temperature control command and outputting the result to the color output circuit as digital data, arbitrary color temperature control can be easily performed.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing a conventional example of a color signal output circuit, Fig. 2 a, b, and c are explanatory diagrams on page 14 of how to take white balance, Fig. 3 a, b are explanatory diagrams of color temperature adjustment,・Figure 4 is a block diagram of a digital preview receiver including a color temperature control device according to an embodiment of the present invention. Figure 6 is a circuit diagram showing a specific circuit example of an embodiment of the present invention. FIG. 2 is a functional block diagram for explaining the invention. 31...Microcomputer, 32...
...Operation keys, 33...Remote control transmitter, 34
...Remote control signal receiving circuit, 35...
Memory element, 39...Digital signal processing circuit, 4
o... Color output circuit, 41... Drive circuit, 42... Picture tube, 61, 52, 53...
...D/A converter, 54, 55, 56... amplifier circuit, 67, 58, 59... drive circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2

Claims (3)

[Claims] (1) Equipped with a picture tube that has a device for emitting light of three different colors, an output circuit that outputs color signals to drive the picture tube, and a control circuit that controls the gain of this output circuit. . A color temperature control device that changes the color temperature of an image emitted onto a picture tube by changing the gain of the output circuit. (2) Equipped with a device that can control the gain of the output circuit using digital data, and by changing the digital data,
2. The color temperature control device according to claim 1, wherein the color temperature control device changes the color temperature of a picture tube. (3) Store a standard value of digital data for adjusting the gain of the output circuit in a storage element, and calculate the standard value with data for changing the color temperature, and use the result as the data for the gain control. 2. The color temperature control device according to claim 2, wherein the color temperature is changed from a standard value by changing the color temperature from a standard value.