JPS6051884A - Charactor superinposition display - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a character superimposition display capable of switching the color tone of displayed characters in a display device that superimposes characters on both sides of the image receiving surface of an image receiver. .

Prior art When displaying characters in a superimposed manner on the image receiving screen of a conventional television receiver, a character superimposing display device is used which superimposes characters of a color tone of Qli-1 on both sides of the image by adding the character signal to the entire video signal. -ta. FIG. 1 is a block diagram showing a conventional character superimposition display, in which an output section 1a of a video signal source 1 is connected to an input section 2a of a receiver 20, and is composed of a synchronizing signal separation circuit 3 and a waveform shaping circuit 4. A central processing unit (hereinafter simply r CI) U J) 7t
= connected, and the output section 6C was connected to the input section 2a of the image receiver 2 via the diode D. Then, when the character 1 number is input and stored from the CPU 7 to the character signal generation circuit B, it is synchronized. A character signal is output in synchronization with the synchronization signal from the circuit 5, and the character signal is added to the video signal 1 and input to the receiver 2, and as a result, bright-colored characters are displayed on the receiving screen of the receiver 2. It was displayed superimposed.

However, when a bright object GIJ image is received on the receiving screen, even if it is superimposed on the brightly colored text on the receiving screen, there is little contrast between the image and the text, making it difficult to distinguish between the characters. there were.

Purpose of the Invention The present invention has been made in view of the above, and it is possible to superimpose display characters with excellent visibility by switching the color tone of the displayed characters using a character Yin/Yang switching circuit according to the brightness of the image receiving screen. It is an object of the present invention to provide a character superimposition display device capable of switching the color tone of superimposed characters automatically or manually using a manual switch with an illuminance sensor and a moss mechanism. The license fee will be explained based on FIGS. 2 and 6. In FIG. 2, 1 is a video signal source,
The output section 1a of the video signal source 1 is connected to the input section 2a of the receiver 2, and the first input signal of the character signal generation circuit 6 is connected to the output section 1a of the video signal source 1 through a synchronization circuit 5 consisting of a synchronization signal separation circuit 6 and a waveform shaping circuit 4. A central processing unit (hereinafter simply referred to as "CPU") 7 is connected to the sixth input section 6b of the character signal generating circuit 6.
The output section 6C is connected to one input section 8a of the character Yin-Yang switching circuit 8, and the output section 9a of the switch circuit 9 is connected to the other input section 8b of the character Yin-Yang switching circuit 8.
The output section 8C is connected to the input section 2a of the image receiver 2.

Father, Figure 6 is a circuit diagram showing a specific example of the character Yin/Yang switching circuit 8 and switch circuit 9 in Figure 2.
One human power section 8a of the character Yin/Yang switching circuit 8 is connected to the skin open contact 82 of the relay 81 via a diode D2, and is grounded via resistors RJ, R2, and R3.

In addition, a transistor T1 is connected to the connection point between the M resistors R1 and R2.
The emitter of a transistor T1 is connected to the connection point between the resistors R2 and R5, and the collector of the transistor T is connected to the normally closed contact 86 of the relay 81. The movable contact 84 of the relay 81 is connected to the output section 80 of the character Yin/Yang switching circuit 8, and the coil 85 is connected to the other input section 8b.

Furthermore, a resistor R4k is connected to the emitter of the transistor T.
A constant voltage source 86 is connected thereto.

Furthermore, a Jd diode D3 is connected to the output section 9a of the switch circuit 9.
and the cathode of the diode D4 are connected, the anode of the diode D is connected to the DC power supply 92 via the first switch 91, and the anode of the diode D4 is connected to the output section 93a of the illuminance judgment circuit 9. There is.

Further, the output section 9roa of the illuminance judgment circuit 93 is connected to the collector of the transistor T2, the emitter of the transistor T is connected to one input section 9rob, and a resistor R5 is connected between the base and the emitter. The base of the connection is connected to the output of the differential amplifier Q through a resistor R6.

A resistor R7 is connected between the non-inverting input part of the input part 9Fib and one input part 9Fib.
is connected, and the non-inverting input portion is grounded via resistor R8.

Father 1. The inversion input section of the differential excitation intensifier QI is connected to the input section 93c of the curved blade, and a resistor R0 is interposed between the input section 93b on one side and the manual section 93c on the other side.

Furthermore, one input section 93b of the illuminance determination circuit 93 is connected to the DC source 92 via a second switch 94, and the other input section 93c is grounded via an illuminance sensor 95. The first switch 911'
i, for example, a lighting switch or a manual switch for turning on the vehicle's lights at night; the second switch 94 is, for example, an ignition switch;
*The sensor 95 is constructed of, for example, a photo-quaternary element using a light guide effect or an optical sensor using a photowake effect, and is installed near a television camera or the like.

In addition, the video signal source 1 is, for example, Q for monitoring the rear of the vehicle.
) is a television camera.

Operation Next, the operation of the character superimposition display device according to the present invention having the above configuration will be explained in detail.

FIG. 4 shows voltage waveforms at various parts of a block diagram showing a preferred example of the present invention in FIG.
The video signal shown in FIG. Further, the potential of VB (volts) corresponds to the dark part of the image, and the higher the voltage, the brighter the part of the image is. When the video signal shown in FIG. The first human power section 6a of the signal generation circuit B [human power section 71. Further, the vertical synchronizing signals shown in FIG. 4O are respectively input to the second input section 6a'.

The character signal generation circuit 6 outputs the character signals input and accumulated from the CPU 7 to the output section 6 in synchronization with the horizontal and vertical synchronization signals.
C to one of the human power sections 8a of the character yin-yang switching circuit 8.

At this time, the character signal waveform outputted from the output section 6C is as shown in (i) in FIG. 4. In FIG. 3, when the first manual switch 91 is turned on, or the second manual switch 94 is turned on, and
When 3a is still at potential, relay 81 of character Yin-Yang switching circuit 8
The coil 85 is energized to connect the normally open contact 82 and the movable contact 84.
is closed, and a circuit is formed so that the character signal shown in FIG.

Therefore, the character signal is added to the video signal shown in FIG.

At this time, the characters are brightly colored.

Conversely, when the first manual switch 91 is turned off and the output section 93a of the illuminance determination circuit 93 is in the low 4th position, the coil 85 is not energized, the normally closed contact 83 and the movable contact 84 are closed, and the fourth When the character signal shown in FIG. However, the emitter potential of the transistor T is biased to approximately VBC volts by the constant voltage source 86 and the resistors R4+R3, and the potential of the output section 8C, which has decreased due to the on-action of the transistors T and U), is below VBC volts. It won't go down.

Then, due to the ON action of the transistor T1, the fourth
The character signal is subtracted from the video signal shown in Figure 4.
The character superimposed signal shown in ' is sent to the receiver 1'4; the human power σ is sent to the receiver 2. When this θ〕U) character, the character 1-1 is VB
-AI is a dark color because it is a signal of the potential of
O) It becomes a letter.

Furthermore, the present invention U] will be explained about the operation of superimposing characters on the image receiving screen of a rear monitoring device using a television camera mounted on a vehicle, for example. First, at night, the image receiving screen is almost entirely dark;
When the lighting switch, which is a manual switch 91, is turned on, or when the illuminance sensor 95 detects that the amount of outside light is low, a text signal is added to the video signal by excitation of the coil 85, and bright-toned text is superimposed on a dark screen. be done. Next, during the daytime, the entire image receiving screen is almost entirely bright, and when the lighting switch is turned off and the illuminance sensor 5 detects that there is a large amount of external light, the coil 85 is turned on and off. Transistor T.

0] Due to the ON action, the character signal is subtracted from the image signal, and the dark tone U] character is displayed on the bright screen.

Note that the character Yin/Yang switching circuit and the switch circuit are not limited to the embodiments, and may be used to automatically or manually switch to a good color tone (for visual recognition of the superimposed characters depending on the brightness of the screen). good.

Q. Effects of the Invention The character superimposition display having the above-mentioned configuration has the following effects.
It is something that

(b) The characters displayed on the iL screen can be changed to characters in bright colors such as white characters, or characters in dark colors such as black characters, depending on the brightness of the image receiving screen. can be displayed.

(b) The color i and In of the superimposed characters can be automatically or semi-automatically switched by the action of the illuminance sensor or lighting switch, providing excellent operability.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a conventional character superimposition display. Figure d52 is a block diagram showing a preferred embodiment of the present invention. FIG. 6 is an electric circuit diagram showing a specific circuit example of the character Yin/Yang switching circuit and the switch circuit constituting the present invention. Fig. 4 1r, f, dE Each part θ of the block diagram shown in Fig. 2)
FIG. 3 is a characteristic diagram showing a voltage waveform. 1... Video signal source, 2... Image receiver, 3...
... Synchronization signal separation circuit, 4 ... Waveform shaping circuit, 5 ... Synchronization circuit, 6 ... - Character signal generation circuit, 7 ... Central processing bag +# , 8...-character Yin-Yang switching circuit, 9... switch circuit. "Niji 1♀Kaise, J: Person A Niles Parts Co., Ltd. No. 1@

Claims (3)

[Claims] (1) A synchronization circuit connected to the video signal source that completely separates the synchronization signal for character display from the video signal, and outputs the character signal input and accumulated from the central processing unit in synchronization with the output signal from the synchronization circuit. Preferably, a character signal generation circuit connected to a synchronization circuit and a central processing unit, and a character signal from the character signal generation circuit are displayed in a superimposed manner on both sides of the image receiver of a receiver that receives the video signal, and the character signal is displayed in a superimposed manner by the input of a switch circuit. A character superimposition display device comprising a character signal generation circuit, an image receiver, and a Sochi circuit for switching the color tone of the displayed characters. (2) Switch circuit? The character superimposition display device according to claim 1, characterized in that the display device includes an illuminance sensor. (3) The character superimposition display according to claim 1, characterized in that the switch circuit is constituted by a lighting switch.