JPS6043989A - Automatic white balance adjusting device - Google Patents

Abstract

PURPOSE:To eliminate the fluctuation of a very small white balance by pausing the operation of the titled device, when a white balance goes into some prescribed range by the titled device. CONSTITUTION:The respective beam currents of the time of a low voltage power source and the time of a high voltage power source of three primary color parts are measured, and the respective measured values are inputted to a comparing and operating means 33, compared and operated with the reference data stored in a storage means 31, and the shift of a white balance is detected. In case the shift exists in the outside of some range, an operational amplifier is controlled through an amplification degree and DC bias control means 34. If three colors go into the range, the operation of the control means 34 and a reference primary color voltage control means 32 is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is applicable to color television receivers, color monitor televisions, and other video P14J devices using color brown color. This invention relates to a rib balance adjustment device.

Conventional configuration and M points between them Conventionally, white balance (d manually adjusted n or (r-L beam current detected and automatic white balance adjusted so that the beam current matches the absolute value of the reference) There was an adjustment device.The latter is very convenient, and if the cathode emission level of the cathode ray tube changes over time due to factors such as temperature, it will automatically make corrections, but even if the temperature has stabilized, it will not make corrections. If you continue to do this, the bright line for measuring the beam current will become like a cathode ray tube.
Alternatively, there were shortcomings such as isolated noise and loss of white balance in the no (iM) state.

Purpose of the Invention 1] The present invention eliminates such conventional drawbacks by comparing the detected beam current with a pre-stored reference voltage value, and detects an image if the drift of the beam current falls within a certain range. VC is set such that the DC level of the amplification stage and the limit j of Jso1llll', '1 degree are fixed and the reference voltage is not generated.
By fixing the control operation in L, the above-mentioned inconvenience is eliminated.

Structure of the Invention The present invention provides a primary color signal amplifier that amplifies red, green, and blue primary color signals and can individually vary the DC level and amplification degree of each; The output of the amplifier is applied; (2) a reference primary color voltage generating means for generating a high beam current and a high beam current; (-) a switching circuit for switching between the reference primary color voltage and the primary color signal and supplying the signal to a primary color signal amplifier; One of the d!lI
The determined value of the beam tE current and the other two beam currents are adjusted to the above [la-flow level and increase a first control means for controlling the amplitude of the reference primary color voltage; and a second control means for fixing the DC level and the amplification degree and stopping the supply of the reference primary color voltage if the measured beam current falls within a certain range. 2 control means, it is possible to eliminate the problem of blurring as a side effect during automatic white balance adjustment, and to always obtain images with a well-balanced white balance.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 depicts the basic part of the entire circuit of this exact example, and shows only one primary color part of each primary color.

2 shows a specific example of the control circuit shown in FIG. 1.

The primary color signal is applied to the input terminal 1 and is applied to the operational amplifier 6 through the n-signal switch 18. The resistors 2, 3.degree. 4 and the transistor 5 set the amplification degree and DC bias of the operational amplifier 6 to arbitrary values. The output of the operational amplifier 6 is amplified to a voltage sufficient to drive a cathode ray tube by a transistor 7 (r) and resistors 8 and 9.

The collector of the transistor 7 is a PNP type transformer/star 1.
11 (
]γi: 11 f, + (Q and can-1 of the cathode ray tube
・Drive ゛. The diode 12 is connected between the PNP transistor 10 and the emitter, and the diode 12 is connected between the PNP transistor 10's terminal and the emitter.
Pl・Lanzosta 1o Heath, between emitters or vice versa・
・It functions as a storage device in the event of an IAS, and has a function to quickly charge the cathode floating container. All cathode current flows through the collector of transistor 1o and resistor 1
3 is detected by the A/D converter 14 based on the voltage drop across both ends of the signal. The A/D converted data is the control circuit I18? '1
1.5.

↑1ill ii Hit Il l: 516 (consists of bow, microcomputer and memory; jL, if control 11 is required, start '1till
! rl similar t1 D/A conno (-evening 16 and O・
One person sends data to the D/A converter 17 for the Kane system i:ill, and controls the onset voltage of the operational amplifier and the Kane.

On the other hand, the reference primary color voltage for measuring Beano current is
Usually, two types of power supplies, a low voltage power supply 19 and a high voltage power supply 20, are prepared and applied to the signal switch 18 through a signal switch 21.

Next, the operation of the VC will be explained with reference to FIG.

First, we obtain a color television receiver that has undergone all adjustments, including white balance, in the factory. Place this color television receiver (R) and connect the signal switch 18 to terminal B.
(When switched to I'ill, the information signal is turned off +!l: Device 2
By switching and connecting 1 to the high voltage power supply side and the low voltage power supply (till), in addition to the reference primary color voltages of 11. from the low voltage power supply 19 and the high voltage power supply 20, all operational amplifiers 6,
The beam current at that time is detected as a voltage from one end of the resistor 13, converted to a digital signal by the A-D converter 14, and the value is stored in the initial reference data storage means 31. 1] Similarly for the two primary color portions of t (C, add a low voltage power supply and a high voltage power supply to an operational amplifier (not shown), measure the beam current at that time, and store it in the initial reference data storage means 31. Therefore, six types of reference data are stored in the initial reference data storage means 31.

Then, while the Australian color television receiver was in operation, 1.
- Horizontal or vertical blanking period (Figure/
l-3zu/) Example: tJ, ITi, Direct Branging Period)
, a reference source voltage control means 3 which operates based on vertical pulses;
2, 1: During the vertical blanking period, the signal switch 18 is connected to the terminal a side, and the signal switch 18 is connected to the terminal a side during the vertical blanking period. Switch the 21C low voltage power supply 19 and the high voltage power supply 2o to fL, and measure the beam current at that time.Similarly, for the other two primary color parts, 1 blanking period 7
The heel current of 1"L It is all i1!11 constant. That is, during each blanking period, for example, by a time division method, when the three primary color parts are at a low voltage power supply, and at a high voltage power supply, If+
The beam current of 2't is determined 1flll, and each measured value is passed through the A-D Compaq 14 to the comparison calculation means 33.
VC is taken in, and here the rf+ is stored in the storage means 31 in advance.
2 memories, +1. A comparison calculation is made with the reference data that is being used to detect a deviation in white balance. Any-Ironozu/1. If it's outside a certain range, increase it by 11? The operational amplifier 6 is controlled through the DC bias suppressing means 34. Note that the switching of the bow switching device 18 does not have to be performed every horizontal or every vertical blanking period, but may be performed at any period.

Then, within a certain range of fluctuations in the measured beam current, 3
If both colors are input, the comparison output discrimination means 35 outputs an output to stop the operation of the amplification degree/DC bias control means 34 and the reference primary color voltage control means 32.

Thereafter, the automatic white balance adjustment operation will not be performed unless the television receiver or color monitor is turned on again, or the user commands the automatic white balance adjustment device to operate again.

As described above, the effect of the invention is that the white balance can be adjusted automatically by stopping the white balance operation within a certain range using an automatic white balance adjusting device. The brightness of the retrace line that occurs as a side effect during white balance adjustment and the minute white balance fluctuations caused by noise are eliminated, and a stable image with a good white balance can be obtained at all times.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a television receiver according to an embodiment of the present invention, and FIG. 2 is a block diagram showing a specific example of the control circuit of FIG. 1. 1... Primary erotic bow input stop 111 child, 6... operational amplifier, 7.10... transistor, 14...
... A/D converter, 15 ... Control circuit, 16.
17...D/A-r7 converter, 18.21...
The signal is a switch, 19 +20... (quasi-primary color voltage source.

Claims (1)

[Claims] The primary color signals of red, green, and blue can be amplified and the DC level and amplification degree of each can be individually varied.
There is a primary color intensifier that emits pressure, and a color cathode ray tube that reproduces a color image when its output is applied.
/L beam current detection circuit, and the reference 'r1.
Memorize the beam current of ti'J of uI:f-1 in advance and compare it with the value of n: +1e! If you control (/C)
Where is the said σI11 determined: converted beam? An automatic white balance adjustment device that fixes the DC level and the degree of amplification and fixes the control operation by not generating the reference voltage when the drift of the d current falls within a certain range.