JPS5822909B2 - color tv station yuzuki - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color television receiver in which the white balance can be shifted to a higher color temperature side using a color signal.

In conventional color television receivers, once the white balance is adjusted, all images are viewed at the same color temperature. Although it has the advantage of being able to visually reduce the degree of color unevenness that may occur on the cathode ray tube when there is high brightness in the image, it has poor color reproducibility of skin tones. It is known that it has the following drawbacks:

Therefore, the present invention detects a desired part of an image, that is, a part with high luminance and close to white, and changes the color temperature of that part to make the white part more white without deteriorating the reproducibility of skin tones. The object of the present invention is to provide a color television receiver that is visually appealing and that can visually reduce the degree of color unevenness.

In order to achieve the above object, the present invention includes a circuit that detects whether the amplitude of each of the red, green, and blue signals exceeds a predetermined set value, and a The screen was configured to have a circuit configured to shift the white balance of that part of the screen to the side with a higher color temperature, and the red, green, and blue signals all exceeded the set values and the screen became whitish. I only change the white balance between the shots.

Hereinafter, one embodiment of the present invention will be explained based on the drawings. In the drawings, R, G, and B are red, green, and blue signals, respectively, P is a luminance signal, and 1, 2.3 are polarities of an AND circuit 4.5. Inverting circuit for matching, 6 is a cathode ray tube, 1 and V2 are DC power supplies, TR is a luminance signal drive transistor, TR
2 is a switching transistor; TR3 to TR5 are blue, green, and red output transistors, respectively; R1 to R3 are semi-fixed volume controls for determining the setting value for changing the white balance;
4 is the collector resistance of the transistor TR1, R5 is the resistor that is connected in parallel to the drive adjustment volume R6 when the switching transistor TR2 is turned on, R7 is the drive adjustment volume, and R8-R1° are each the transistor TR.
The collector resistances of transistors TR3 to TR5 and R1□ to R13 are emitter resistances of transistors TR3 to TR5, respectively.

Red signal R1 green signal G, blue signal B are each inverted circuit 1
, 2.3, the outputs of the inverting circuits 1 and 2 are added to the AND circuit 4, and the output of the AND circuit 4 and the output from the inverting circuit 3 are added to the AND circuit 5, so that the signals R, G, B are obtained. A of
ND operation is performed, semi-fixed volume R, J R2J R
3 detects the presence or absence of a luminance signal pulse higher than the set signal, and outputs when each signal R1G, B is higher than the set signal of the semi-fixed columns R1, R2, R3.

Therefore, depending on the presence or absence of the output of the AND circuit 5, the magnitude of the blue signal applied to the blue cathode of the cathode ray tube 6 is changed by switching the switching transistor TR2 and connecting the resistor R5 in parallel to the drive adjustment volume R6 or not. , resulting in a change in color temperature.

That is, when an output is output to the AND circuit 5, the switching transistor TR2 is turned on, the resistor R5 is connected in parallel to the drive adjustment volume R6, and the blue signal is applied from the blue signal output transistor TR3 to the blue cathode of the cathode ray tube 6. The color temperature becomes higher when it becomes a dog.

As detailed above, according to the present invention, only when the amplitudes of each of the red, green, and blue signals exceed a predetermined setting value, the white balance of that part of the screen is changed to a color. Since the structure is configured so that the temperature moves toward the higher side, it is normally used at a color temperature that does not deteriorate the reproducibility of skin tones, but it can also be used to capture the desired part of the image, that is, the part with high brightness and close to white. By detecting this and changing the color temperature of that area, it is possible to make the white part look more like a mortar, and visually reduce the degree of color unevenness.

[Brief explanation of the drawing]

The drawing is a circuit diagram showing one embodiment of the present invention. R...Red light, G...Green light, B...
...Green signal, D...Brightness signal, 1.2,3
...Inverting circuit, 4゜5...AND circuit, 6...Cathode ray tube, Vl, ■2...
DC power supply, TR1... Brightness signal drive transistor, TR2... Switching transistor, TR3 to TR5... Output transistor, R1
-R3...Semi-fixed volume, R6...
Resistor, R6...Volume for drive adjustment.

Claims (1)

[Claims] 1. A circuit for detecting whether the amplitude of each of the primary color signals of red, green, and blue exceeds a predetermined setting value; and a circuit configured to shift the white balance toward a higher color temperature only when the amplitudes of the primary color signals exceed the predetermined set values. Machine.