JPH02107092A - Color television receiver - Google Patents

Abstract

PURPOSE:To reproduce the skin color with a natural color by interlocking a hue adjusting action by a color signal processing circuit to the variable action of a white balance. CONSTITUTION:When a first control voltage Vc1 of a white tone control circuit 4 is adjusted so as to become higher than direct current bias voltage Vb, V01<V02 is obtained, the emitter direct current potential of a driving transistor Tr1 for B becomes lower than that of a driving transistor Tr3 for R and the picture becomes slightly blue as a whole. The emitter potential of the transistor Tr7 of a control voltage adder circuit 6 advances, the voltage of (37) pins and (40) pins of IC 1 respectively advances, the hue is dislocated in the end direction a little and the control is executed in the direction in which the color of the picture becomes slightly thick. Thus, the skin color is corrected to the color close to the nature, a first control voltage Vc1 is adjusted so as to become Vc1<Vb, and then, the action of the reverse direction is not executed and the color is corrected so as to become the color close to the nature.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a color television (TV) receiver, and particularly to skin tone adjustment thereof.

(B) Conventional technology In recent color TV receivers, the white balance of the screen is not fixed uniquely, but is changed according to the surrounding brightness, etc., so that more natural white can be reproduced. This adjustment operation is called white tone control. In addition, a circuit that can perform such control automatically according to the surrounding brightness is disclosed in Japanese Patent Application Laid-Open No. 49-134233 [97(5)
) K7] etc.

(C) 7 Problems to be Solved by the Invention However, if such white tone control is performed to make the entire screen appear slightly reddish or bluish, the color balance will be disrupted, and skin tones in particular will appear unnatural. become. That is, a bluish screen gives the impression that skin tones are whitish, and a reddish screen gives the impression that skin tones are darker.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a color TV receiver that eliminates these drawbacks and is capable of reproducing skin tones in their own natural colors even when white tone control is performed.

(d) Means for Solving the Problems In the color TV receiver of the present invention, the hue adjustment operation in the color signal processing circuit, more preferably the hue adjustment operation and the saturation adjustment operation, are performed in the above-mentioned white tone control operation, that is, in the white tone control operation. It is linked to the variable balance movement.

(E) Effect 1-According to the purchase, the color deviation caused by the white tone control is corrected by the hue adjustment operation, so that the skin tone is reproduced in a color close to natural, and the deviation in saturation is also corrected. Through the correction, the skin color expressed in l'11 becomes closer to a natural color.

(f) Embodiment FIG. 1 shows an embodiment of the essential parts of a color television receiver according to the present invention. In the same figure, (1) is ACC,
This is an RC for color and luminance signal processing and synchronization that includes APC, color demodulation circuit, etc. Here, for example, Matsushita Electronics Co., Ltd.
AN5301NK manufactured by Co., Ltd. is used. This I
C(1) contains a color (saturation) control circuit to which a control voltage is applied from the [phase] bin and a tint (hue) control circuit to which a control voltage is applied from the 0 pin. The B-Y, G-Y, and R-Y color difference signals obtained by color demodulation are output to the θ, [phase], and [phase] pins in this order, respectively.

(2) is a color drive circuit, and this circuit consists of three drive transistors (T r
1) (T r −) (T r , ) and the IC (1
) is provided with a luminance signal amplifying transistor (Tr, ) to which the luminance signal (Y) from the 0 pin is input to the base, and the collector output signal of this amplifying transistor (Tr, ) is RC
The drive transistors (T r 1) (T
The configuration is the same as the conventional one, in which the primary color signals (R), (G), and (B) applied to each emitter of the color picture tube (T r +) and obtained at each collector are applied to each cathode of the color picture tube (3). I'm picking it up.

Next, (1) is a white tone control circuit, and this circuit receives the first fil+ 911 for white tone control from the control voltage generation circuit (5).
It pressure (Vc,) is applied to one base through a resistor (R,4) and a resistor (R,)(R,)(
A differential pair of transistors (T r ,) (T r
) and a constant current source transistor (T r #), etc., and the collector output voltage of each differential pair transistor is
'L is applied to each emitter of the drive transistors (Tr, ) and (Tr3) via resistors (R, , ) (R, , ), respectively. Note that (C1) is a smoothing capacitor for noise removal.

Next, (6) is a control voltage adding circuit, and this circuit, on the one hand, is a control voltage adding circuit for saturation adjustment introduced from the +7'+7 control voltage generating circuit (5) via a resistor (R+s). 2 control voltage (Vct) is semi-fixed resistance (V Ry
) and resistors (R, a) (R, , ) and is applied to the [phase] pin of the IC (1) through the resistor (Rls), and on the other hand through the resistor (RII). The third control voltage (Vct
) are similarly semi-fixed resistances (VRs) and resistances (R,.) (
R, l) is added to the DC voltage obtained by the resistance (R.

, ) The following configuration is further added to the basic configuration in which the voltage is applied to the 0 pin via the 0 pin. That is, the aforementioned first control voltage (Vct) is input to the base of the emitter follower transistor (Tr, ) for buffering and taken out from the emitter, and then the aforementioned first control voltage (Vct) is inputted to the base of the buffer emitter follower transistor (Tr, ) and taken out from the emitter through the resistors (Rts) (R1, ). This is the configuration that is added to the second and third control voltages (Vct) (Vct). Note that (C3) (Ct) is a capacitor for noise removal.

Further, the control voltage generation circuit (5) may be
H. The first to third control voltages (V c 1) (V c, ) are controlled by variable resistors (V R, ) (V R, , ) (V R, 1) that divide the DC voltage (+Vcc+), respectively.
(V c s>), but in addition to this, each of the control voltages (V
c , )(V c , )(V c s).

The embodiment shown in FIG. 1 is generally constructed as described above, and its operation will be explained below.

Each collector output voltage of the differential pair transistors (Tr1) (Tr-) of the white tone control circuit (4) is 70. ) (V., ) changes as shown in Figure 2 depending on the first control voltage (VCl), so now adjust the first control voltage (Vc,) to be higher than the DC bias voltage (Vb). Then, V I, , < V. 8, and the emitter DC potential of the B drive transistor (Tr+) becomes R.
It is lower than that of the drive transistor (Trs). At this time, the DC potential of the B cathode of the picture tube (3) becomes 6 lower than that of the R cathode, and the screen as a whole becomes slightly bluish.

On the other hand, as shown in Figure 3, the hue control circuit in rc(1) shifts the hue toward the edge when the voltage at pin 0 increases.
When the voltage of the [phase] pin becomes low, the saturation is shifted in the 7-Zenda direction.On the other hand, the saturation control circuit is designed so that as the voltage of the [phase] pin increases, the saturation increases, and as the voltage of the [phase] pin increases, the saturation decreases. Therefore, if white tone control is performed so that the first control voltage (Vc+) becomes high as described above, the emitter potential of the transistor (Tr, ) of the control voltage addition circuit (6) will rise. , thereby increasing the voltage on the pin and [phase] pin, respectively. Therefore, the bluish hue of the screen is slightly shifted toward the edge, and the screen color is controlled to become slightly darker.

Therefore, when it comes to skin tones, the white tone control brings the bluish and pale skin tones back towards yellow by slightly reducing the saturation.
This means that the color has been corrected to be close to natural.

Further, the first control voltage (VCl) is V c l < V b
If you adjust the white tone control so that it becomes 1. The operation in the opposite direction to that described in F is performed, and the reddish hue of the screen is slightly shifted in the 7 Zenda direction, and the saturation is slightly lowered by L, thereby correcting the skin tone to a color that is close to natural. It is.

(g) 5! Brightening effect The color TV receiver of the present invention is capable of reproducing natural skin tones by linking the hue adjustment operation to the white tone control adjustment when the white balance of the screen is slightly changed. It can be corrected so that By linking the white tone control operation with the saturation adjustment, the skin color correction can be performed more accurately to give a natural color.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the essential parts of a color TV receiver according to the present invention, and FIGS. 2 and 3 are control characteristic diagrams of each part thereof. (1): Color and luminance signal processing and synchronization IC1 (2)
Two-color drive circuit, (4): White tone control circuit, (5): Control voltage generation circuit, (6
): Control voltage addition circuit. Procedural amendment (indication of spontaneous case No. 1065 Patent Application No. 261834 Name of the invention Color television receiver Amendment to the case Relationship to the case Patent applicant name (18B) Sanyo Electric Co., Ltd.

Claims (2)

[Claims] (1) In a color television receiver in which the white balance is varied by changing the DC level of the color signal applied to the color picture tube, a color signal processing circuit is used to perform the white balance variable operation. A color television receiver characterized in that hue adjustment operations are linked. (2) In a color television receiver in which the white balance is varied by changing the DC level of the color signal applied to the color picture tube, a color signal processing circuit is used to perform the white balance variable operation. A color television receiver characterized in that a hue adjustment operation and a saturation adjustment operation are linked.