JPS6074786A - Television receiver - Google Patents

Abstract

PURPOSE:To eliminate the need for adjustment at mode switching by increasing the contrast ratio between a display signal and a television video image signal when a superimposing display mode is detected in a receiver having the superimposing display mode. CONSTITUTION:When the superimposing display mode is detected, a transistor TR5 and a diode D3 in a detection circuit 8 are turned off. Thus, the voltage of a pin 13 in an IC16 is higher than that at the single display mode of an external RGB signal. Each amplitude is adjusted so as to increase each gain of the RGB signal in proportion to the rise of the voltage of the pin 13, then the circuit is controlled to increase the contrast ratio of the character and the TV picture.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a television receiver, and particularly to a television receiver capable of displaying display information such as characters from an external device.

Prior art: Recent television receivers display display signals (character pattern signals, etc.) from a pan 71 personal = + 7 viewer etc. on the screen alone or by superimposing them on the television image. There is something that can be released.

By the way, I am currently watching the TV video of Basohun Kamoji Patashii 8 Swords (No. 11YJ(a)) No. 8 (same figure (b
)) (Considering the superimposed display Morton, in this case, only the 'H' (high level) part representing the character part of the pattern signal is replaced with the video (tl %), so both The signal waveform after synthesis is as shown in Figure 2(c), and therefore, the level difference between the text and the video becomes small, making the text very difficult to see.For this reason, conventionally,
When in superimposed display mode, the contrast between text and images was adjusted to be optimal, but it was extremely troublesome to have to make adjustments every time I switched to the above mode.

(c) Purpose of the Invention The present invention has been made in view of the above points. An object of the present invention is to provide a pre-pin 3-pin receiver capable of automatically switching the digital trust to an optimum state.

2) Structure of the Invention The display receiver Rm of the present invention is capable of displaying information from an external device (
It is configured to detect the superimposed display mode of No. rJ, and control to increase the contrast ratio between the display signal and the television video signal based on the detection output.

(E) Embodiment FIG. 2 shows the main parts of an embodiment of a television receiver according to the present invention. This embodiment can be roughly divided into a tuner (1) and a VIF (video intermediate frequency) circuit (2). > TV signal receiving section (3) consisting of a TV signal/external synchronization signal cut-off PA circuit (4 channels, horizontal,
Vertical synchronization/deflection section (5) and TVI! I! An image signal processing unit (mutual), an industrial association standard 21-bin multi-connector (7) for connection with external equipment, an AV control signal detection circuit (8) for internal/external switching, and an external RGB digital camera. Before the control of (υ
Replacement part (91 to 48 completed).

The synchronization/deflection unit (manufactured by Tokyo Kochudenki Co., Ltd., in which the TV composite video signal after VIF detection or the external synchronization signal described later is input to the T4 [phase] pin through the switching circuit (4)) Synchronous/deflection drive IC: L A7820 (It
), a vertical amplitude switching circuit (12) connected between the C-bin and the vertical deflection circuit, and a horizontal position switching circuit (13) connected to the ■ pin.

Note that the above IC (11) has an internal configuration similar to the third section. <v Rx) (v R2), etc., and the horizontal position switching circuit (13) is equipped with a switching transistor (TR
3) (TR4) and 4th town variable resistance (VR4) etc. 1
However, the detailed explanation will be omitted since it is not directly related to the present invention.

Next, the TV video signal processing section (6) includes a comb-shaped filter <14) for separating a color signal and a luminance signal from the TV composite video signal introduced through the switching circuit (4), and the color The signal (C) is input to the ■bin, and the luminance signal υ(Y) or [
7 processing IC: L A760ON (1
5) etc.

In addition, in the multi-connector (7), each input/output signal connected to pins ①~ is determined by the above-mentioned standard, but here, in particular, the external A synchronization signal (external synchronization signal) from the device is input, the above-mentioned AV control signal is manually input to the C bin, and each of the external RGB signals representing character patterns etc. from the external device is [phase], It is important to note that the 0.0 pin is input. Furthermore, the bin has a YS control for switching between the external RGB signal and the internal RGB signal (that is, demodulated from the TV signal). A signal is input.

Further, the control signal detection circuit <8> includes a two-stage connected switching 1-transistor (T R5) that is turned on and off by the AV control signal from the C bin of the multi-connector (7).
) (TR6) as the main element, and the low level signal "L" and the high level signal "H" obtained at the lefter (point B) of the subsequent transistor (TR6) are connected to the switching circuit (4) and the vertical amplitude. The transistor (T) of the switching circuit (12)
RI) and the horizontal position switching circuit (13) as a switching signal for the run transistors (TR, li).

Ir1. Later, the RGB signal control/switching section (9>
16), the external RGB signal from the multi-connector (7) is input to the @, [phase], and [stock] pins of %, and the video chroma signal is input to the C, 3, 3, and C bins. For I
The RGB signal and Y (luminance) signal from C (15) are input, and the above-mentioned YS control signal is applied to the C bin, but the following points should be particularly noted here.

As shown in FIG. 4, the IC <16> is equipped with an amplitude adjustment circuit for each of the external RGB signals, and the amplitude of each signal is adjusted by the magnitude of the DC voltage applied to the C bin. Therefore, a brightness/contrast adjustment circuit (17) for external RGB signals is provided as shown in the figure, and in particular, a fifth variable resistor (VH2) for adjusting the contrast is provided here. ) is connected to the 0 point in the detection circuit (mutual) via a diode (D3) and a resistor (R5), which is a major feature. In addition, the sixth variable resistor (VH2) for brightness vR adjustment in the adjustment circuit (17) is connected to the above ■ through the bottle.
The brightness adjustment circuit (see Figure 4) in C(16)
f: This is for applying the uilc voltage.

The embodiment shown in FIG. 2 is generally configured as described above, and below, especially in the case of superimposed display mode of external RGB signals, the brightness/contrast 1n! The operation will be explained focusing on one circuit (17).

First, in the TV signal single reception mode and the superimposed display mode with external RGB signals, the multi connector (7) ■
The AV control signal from the bin becomes "L", and in the RGB signal independent display mode, this control signal becomes "H"), which is predetermined on the external device side. So now,
Assuming that the superimposed display mode is selected, the A'V control signal turns off the transistor (TR5) and turns on the transistor (TR6) of the Nakade circuit (1), causing the point B in the detection circuit (8) to turn off. The voltage becomes "L", which causes the switching circuit (4) to switch to the state shown in the figure, and the VIF circuit (
2) The TV composite video signal from I is used for synchronization/deflection drive.
It is input into the [phase] bin of C(16). Therefore, this I
C operates on TV synchronization signals.

In addition, by supplying the TV composite video signal that has passed through the switching circuit (4) to the external device via the 0 bin of the multi-connector (7), the external GRB signal υ synchronized with the TV synchronization signal is transmitted from the external device. will be input through the above-mentioned converter (7).

On the other hand, in the overlapping display mode, the YS control input 8 applied to the @ pin of the RGB signal control/switching IC (16)
When any one of the external RGB signals from the multi-connector (7) becomes "H", the signal becomes "H".

It becomes “H” only during the “H” period. Therefore, the RGB switching circuit (see Fig. 4) in this IC (16) switches the TV/R from the video chroma processing IC (15) only during the [H] period.
The GB signal is replaced with the external RGB signal and output to the ■, ■, ■ pins. Also, the brightness (Y) in the above IC (16)
The switching circuit uses the brightness adjustment circuit (see Figure 4) in this IC (16) instead of the TV brightness signal only during the "H" period.
Derive the constant DC voltage from to the 0 bin. Each of these signals is then input to a color picture tube drive circuit (not shown).

Here, the IC (16) contains external RGB as described above.
A fIt amplitude adjustment circuit (see Figure 4) is provided, and each iiiu circuit is equipped with a brightness/contrast adjustment circuit (see Figure 4).
The voltage obtained from the fifth variable resistor (VH2) of 17) is input through the ■ pin. At this time, in the superimposed display mode, the transistor (TR5) in the detection circuit (8) is off as described above, and the diode (D3) is also off. Therefore, the voltage at the ■ pin is higher than when in the external RGB signal independent display mode (that is, when TR5 and D3 are on). And, the higher the voltage of the (■) pin, the higher the gain of each of the RGB (ff) is operated, so that each amplitude 1Ill adjustment operation operates. Therefore, in the superimposed display mode, the characters and The contrast ratio with the TV image can be controlled to be large as shown in FIG. 5(a).

Also, the brightness within the IC (16) is u4v1. The DC 11L output from the circuit to the 0 bin through the Y switching circuit is applied from the 6th variable resistor (VH2) in the brightness/mount last adjustment circuit (17) to the brightness adjustment circuit 1 through the ■ pin. Determined by the voltage applied. Therefore, the brightness of the characters on the iTV video can be set using the sixth variable resistor (VH2).

In addition, in the external RGB signal independent display mode, as mentioned above, the AV control signal becomes "H" and the output voltage at point B of the detection circuit (8) becomes "H-", so the switching circuit (4) ) switches to the opposite state as shown. Therefore, the multi-connector (
7) The external synchronization signal introduced to the [F] pin is synchronized.
Since it is input to the [stock] pin of the deflection drive IC (11), external RGB (!) is performed in synchronization with the external synchronization signal.

In addition, the vertical amplitude switching circuit (12) and the water position switching circuit (13)
Although the display area of the screen is switched to the optimum state for each of the external RGB signal display mode (including the external RGB signal mode) and the external RGB signal independent display mode, such a point is outside the scope of the present invention, so we will not discuss it here. The above explanation will be omitted.

(f) Effects of the Invention According to the television receiver of the present invention, in the superimposed display mode of an external display signal and a TV video signal, the foot-last ratio of both signals is determined in the independent display mode of the external display signal. Since it is possible to allow an increase in the number of characters, characters, etc. can be displayed clearly on the TV image, and the contrast will not be too strong and difficult to see when displayed alone. Moreover,
Since such contrast switching is automatically performed, such adjustment is not required each time the mode is switched to the above-mentioned modes, which is convenient.

Note that, contrary to the case of the above embodiment, the same effect can of course be obtained even if the gain of the TV-RGB signal is lowered as shown in FIG. 5(b) in the superimposed display mode. It is.

[Brief explanation of drawings]

Fig. 1 is a signal waveform diagram for explaining problems in superimposed display of an external display signal and a TV video signal, Fig. 2 is a diagram showing a schematic configuration of an embodiment of the present invention, Figs. Figure 4 is not used in this embodiment. A: Diagram showing the internal configuration of the IC.
The figure is a diagram showing display signal waveforms in the superimposed display mode of the above embodiment. (Dan): TV signal receiving section, <4): TV signal receiving/external [;
Synchronous signal switching circuit, (base): horizontal, vertical synchronization/deflection section,
(12)・Vertical amplitude switching circuit, <13): Horizontal position switching circuit (6): TV video signal processing section, (7): 21-bin marteco, I/Futa, (heather): Control signal detection circuit, (9
): RGB signal control and switching section, (17): Brightness/contrast adjustment circuit for external RGB signals. Figure 1 (a) (b), (c) Figure 6 (a), (b) 1 - (

Claims (2)

[Claims] (1) We have carefully engineered a television receiver that has an independent display mode in which display No. 16 from an external device is displayed independently, and a superimposed display mode in which it is superimposed on the TV video signal and displayed. . A television receiver configured to detect when the superimposed display mode is in effect, and control to increase a foot-last ratio between the display signal and the television video signal based on the detected output. (2) The television receiver according to claim 1, wherein the detection output is used to increase the gain of the display signal by a factor of 7 to perform hjI load control.