KR920005059Y1 - Defocusing selecting circuit - Google Patents

Abstract

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Description

Defocusing Switching Circuit

1 is a schematic diagram showing a schematic configuration of a defocusing switching circuit according to the present invention.

2 is a detailed embodiment of a defocusing switching circuit according to the present invention.

* Explanation of symbols for main parts of the drawings

10: combination means 20: automatic focusing amplifier

30: defocusing motor driver 40: switch element

50: motor 60: motor position detection unit

The present invention relates to a defocusing switching circuit, and more particularly, to a defocusing switching circuit capable of controlling a switching state of recording switching on / off defocusing in order to effectively photograph a subject with a video camera and a camcorder. will be.

In general, when shooting a subject with a video camera and a camforder, an appropriate exposure compensation switch is used to adjust the aperture of the camera lens. By using the exposure compensation switch, the subject may be close up to focus by the aperture and synchronized, and then zoomed back to capture the image regardless of the brightness of the background. On the other hand, in outdoor shooting, when the contrast of the subject is strong and the SN ratio is reduced in the shade, and the color is not reproduced cleanly, the shadow part tends to be a green screen. In addition, in the shooting, when the lighting is insufficient, the shadow part corresponds to the part of the steepness of the gamma characteristic, so the amplification degree is large. Therefore, the SN ratio is lowered, so that the color reproduction phenomenon and the afterimage increase. In this case, the use of a high-sensitivity selector switch increases the amplification of the camera image circuit, so that the SN ratio is lowered.

Contrary to the above, when the user wants to sharpen only the subject and fade out the background in an outdoor light, the auto iris is tightened to deepen the depth of field because the light is strong. In this case, a filter suitable for the camera lens can be used to weaken the incident light and open the aperture to shallow the depth of the subject to fade out or fade in the background gradually. There was a problem.

In order to solve the above problems, the present invention provides a defocusing switching circuit capable of more effective shooting by defocusing switching operation when recording or stopping recording by photographing a subject with a video camera and a camcorder. There is this.

The present invention to achieve the above object, Combining means for inputting and combining the defocus control signal and the recording stop signal; An automatic focusing amplifier for amplifying by inputting an AF signal through a switch to switch the combined signal of the combining means; A defocusing motor driver for inputting a combined signal output from the combining means and outputting a driving signal; A motor for operating a signal selected by the switch element; And a motor position detection unit for determining the position of the motor by driving a built-in AF ring by inputting a combination signal of the voltage and the combination means when the motor is operated.

Hereinafter, the configuration and effects of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic diagram showing a schematic configuration of a defocusing switching circuit according to the present invention.

In FIG. 1, the combining means 10 is configured such that the output is at the "high" level when the defocus control signal A and the recording stop signal B are at the "high" level, and the autofocusing amplifier 20 is It is configured to switch and amplify by inputting AF (Auto Focusing) signal.

The defocusing motor driver 30 is configured to input a combined signal output from the combining means 10 to output a drive signal for driving the motor. In this case, the switch element 40 selects one of the output signals of the auto focusing amplifier 20 and the defocusing motor driver 30 as a combination signal of the combination means 10.

On the other hand, the motor position detection unit 60 inputs the combination signal of the combination means 10 and the voltage of the motor 50 operating with the signal selected by the switching element 40 to drive the built-in AF ring 50 And determine the position of the) and transmit it to the defocusing motor driver 30.

2 is a detailed exemplary view of a defocusing switching circuit of the present invention according to FIG.

In Fig. 2, the combining means 10 causes the output to be " high " when the defocus control signal A and the write stop signal B are at " high " level to " turn on " the transistor Q1. When the transistor Q1 is " turned on ", the AF control signal input to a of the autofocusing amplifier 20 is " low " so that the autofocusing amplifier 20 is not operated. At this time, the switch SW1 (SW2) of the switch element 40 is switched toward the defocusing motor driving unit 30, and the motor position detecting unit 60 detects the AF position from the motor 50 and is present through the built-in AF ring. Drive away from position to defocus. When switching from the write stop mode to the write mode, the output of the combination means 10 becomes " low " to turn the transistor Q1 off. When the transistor Q1 is " turned off ", the AF control signal input to a of the autofocusing amplifier 20 becomes "high" and the autofocusing amplifier 20 operates to perform accurate focusing. In this case, however, when the defocusing signal A is input at the "high" level, the switch SW1 should be switched so that the AF signal is selected. On the other hand, the defocusing motor driver 30 has the transistor Q6 and Q3 turned on when the voltage of b is "high", so that the motor 50 is operated and the transistor Q4 when the voltage of b is "low". Q5 is " turned on " so that the motor 50 operates in the opposite direction to the above case. At this time, the AF ring built in the motor position detection unit 60 is set to the intermediate value of the variable resistor VR built in the motor position detection unit 60 to drive away from the current actual focusing position. When the initial value of the motor 50 is small compared with the reference voltage of the resistors R6 and R7 of the motor 30 and the initial DC value of the motor 50, the output of the differential amplifier OP1 becomes "high". When the output of the differential amplifier OP1 becomes "high", transistors Q3 and Q6 are "turned on" to operate motor 50 and at the same time transistor Q7 is "turned on".

When the transistor Q7 is "turned on", the reference voltage is increased to drive the motor 50 to the end opposite to the above direction.

Contrary to the above case, if the voltage at the current motor 50 position is higher than the reference voltage of the resistors R6 and R7, the output of the differential aeration OP1 is "low" and the transistors Q4 and Q5 are turned off. At the same time, transistor Q8 is " turned on " to lower the reference voltage. At this time, the motor 50 is driven to the end in the opposite direction to the above direction. Also, the actual write on / off operation should be operated after sufficient time for defocusing and actual focusing has elapsed even if the defocus inputs a “high” level.

As described above, the present invention has the advantage of controlling the switching of the recording switch on / off defocusing in order to effectively photograph with a video camera or a camcorder.

Claims (1)

Combining means (10) for inputting and combining the defocus control signal and the recording stop signal; An automatic focusing amplifier 20 for inputting and amplifying the AF signal through a switch SW switched to the combination signal of the combination means 10; A defocusing motor driver 30 for inputting a combined signal output from the combining means 10 and outputting a driving signal; A switch element 40 for selecting one of the output signals of the auto focusing amplifier 20 and the defocusing motor driver 30 as a combination signal of the combination means 10; A motor 50 operating with a signal selected by the switch element 40; And a motor position detection unit 60 for determining the position of the motor 50 by driving a built-in AF ring by inputting a combination signal of the combination means 10 and the voltage when the motor 50 is operated. Defocusing switching circuit characterized by.