JPS63221772A - Video camera equipment - Google Patents

Abstract

PURPOSE:To select proper and inexpensive iris with simple operation by selecting two systems where one is to control the iris in response to an output of an image pickup element and the other is to control a position of iris wing to a value corrected optionally by means of a switch. CONSTITUTION:An object image is subjected to luminous quantity control by an iris 2 through a lens 1 and is converted into a video signal by an image pickup element 3. The video signal is outputted via an amplifier 4 and inputted to a smoothing circuit 5 and inputted to a DC amplifier through an adder 6. Then it is outputted to a drive coil 14 via a switch 9 and a wing 16 is moved to control the luminous quantity of the object. On the other hand, a detector 10 detects the position of the wing of the iris and stores it in a memory 12 through a switch 11. Then the signal is fed to a terminal B of the switch 9 via a DC amplifier 13. In switching the switch 9, any of two feedback loops is selected to select the proper iris control system.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a video camera device having an aperture control mechanism.

[Prior Art] As an aperture control WA structure used in a video camera device, the following methods have been proposed in the past.

(b) Absolute value: Attach an encoder or potentiometer to the aperture control axis of the aperture control Ja structure of the vIll system video camera device, read the absolute value of the aperture, and manually manipulate it so that the read value becomes a predetermined value. Alternatively, a servo device performs self-lfJ control.

(b) Aperture control of signal value control type video camera device 911! Regardless of the absolute value of the aperture value of the structure, the average output signal of the image sensor is 1. Alternatively, it is a method that controls the peak value to a constant value.
It is used as a portable camera for broadcasting or a camera for home use, and is relatively inexpensive.

[Problems to be Solved by the Invention] In general, an aperture control mechanism not only keeps the average value and peak value of the output signal of an image sensor constant, but also opens or closes the aperture at α. There are many. At that time, it is desirable to be able to vary the aperture from the current control value to h, double, or quadruple. However, although this can be easily achieved with a conventionally used video camera device having an aperture control mechanism according to method (a) above, there is a problem that the device is large-scale and expensive; In a video camera device having an aperture control V4M configuration using the method (b) described above, especially in a home camera device, the absolute value of the aperture value is not known, so there is a problem that even if you try to open or close the aperture intentionally, it will not be possible. .

The present invention has been made in order to solve the above-mentioned conventional problems, and it is possible to create an aperture control mechanism that can be adjusted arbitrarily according to the output of the image sensor or independently of it by inexpensive and simple operations. The purpose of this invention is to provide a video camera device with improved performance.

[Means for Solving the Problems] In order to achieve the above object, the video camera device of the present invention includes a feedback system for controlling the blades of the aperture in order to keep the video signal constant, and a feedback system for controlling the blades of the aperture. It has a detector that detects the position, and a memory that holds the latest output value of this detector or a value obtained by adding an arbitrary correction f^ to the output value, and stores the output value of the detector in the memory. and a feedback system for setting the value to be maintained, and the two feedback systems can be switched by a switch.
-+ (The configuration includes an aperture control mechanism that enables the

[Function] By having the above configuration, two methods are possible: one in which the aperture is controlled according to the output of the image sensor, and the other in which the position of the aperture blades is controlled to a value corrected to a. You can simply select it with a switch.

[Embodiment] No. i+x is a block diagram schematically showing the main part of an embodiment of the aperture control mechanism in the video camera device of the present invention,
■ is an imaging lens, 2 is an aperture, 3 is an image sensor, 4 is an amplifier for video signal amplification, 5 is a smoothing circuit, 6 is an adder, 7 is a DC amplifier, 8 is a reference voltage, 9 is a switch circuit, IO is A detector for detecting the position of the blades of the diaphragm, 11 a switch circuit, 12 a memory composed of a large capacity capacitor, a FET buffer amplifier, etc., and storing analog information, 13 a DC amplifier, 14 a drive coil for the diaphragm, 15 16 is a brake coil of the diaphragm, 16 is a blade of the diaphragm, and 17 is a switch.

Now, the object image (not shown) passes through the imaging lens l and is stopped at the aperture 2.
After controlling the amount of light, it is imaged on the image sensor 3 and converted into a video signal, which is amplified by an amplifier 4 for amplifying the video signal, and a standard television signal is formed by a process amplifier and an encoder (not shown). On the other hand, the output of the amplifier 4 for amplifying the video signal is input to a smoothing circuit 5, passes through an adder 6, and is input to a DC amplifier 7. When the switch 17 is not pressed, the switch circuit 9 is connected to the A side, so the output of the DC amplifier is output to the drive coil 14, and the blades 16 move to control the amount of light of the subject image. do. Further, when the blade 16 moves, an electromotive force is generated in the braking coil 15, and this electromotive force is manually inputted to the DC amplifier 7 through the adder 6, forming a kind of speed servo closed circuit. Also, an aperture 2, a Dii image element 3. Amplifier 4 for video signal amplification
．． Smoothing circuit 5. Adder 6. DC amplifier 7, switch circuit 9. Drive coil 14. A negative feedback loop is formed through the path of the aperture blades 16, and control is performed so that the output of the slip circuit 5 becomes equal to the reference voltage 8.

On the other hand, the detector lO detects the position of the blade 2 of the diaphragm, and its detection output is connected to the memory 12 through the switch 11 so as to be inputted thereto. Switch ll is switch 17
When is not pressed, it is connected, and the memory 12 outputs the same voltage as the input voltage. The DC amplifier 13 is connected to one side of the output of the memory 12 and one side of the output of the detector 1O, and is connected to the drive coil 1 via the switch circuit 9.
Connected to 4. As described above, when the switch 17 is not pressed, the switch circuit 9 is connected to the A side, so the output of the DC amplifier 13 is not connected to the drive coil 14.

Now, when you press switch 17, first switch ++11
With wt1l open, memory 12 retains the previous state of the detector output. Further, the switch circuit 9 is connected to B. Then, the feedback circuit mentioned above is cut off,
A new negative feedback loop circuit is formed. That is, the detector 10, the DC amplifier 13. Switch circuit 9. Drive coil 14. Feather 16. This is a detector 10. The foot loop operates to maintain the output of the detector 10 at the output of the memory 12, that is, the output of the detector 1O immediately before the switch 17 is pressed.

FIG. 2 is a schematic diagram showing the outline of the mechanism of the main part of FIG. 1. In FIG. 2, 101 is an aperture magnet, 1
02 is an aperture coil including a drive coil and a braking coil; 1
03 is the aperture axis, to4. ios is the joint, 16 is the blade, 1
06 is a fulcrum, 107 is an opening, 10B is a detection magnet, 109 is a magnetic resistance, a de f-kF magnetic sensor, 110
is the amplifier for the output of the magnetic sensor lO9, 108,10
9,110 constitute a detector.

Now, when current flows through the drive coil, the magnet 101
generates a rotational torque, and one rotating shaft 103. Jt1 move 104,
The signal is transmitted to the aperture blade 16 via the filter 105. The blade 16 draws an arc around the fulcrum 106, and controls the light beam of the subject image by varying the surface area of the first part 107.On the other hand, a detection magnet 10B is added to a part of the blade 16, Feather 1
6 moves, the distance from the magnetic sensor 109 whose position is fixed changes, and the magnetic flux density changes, so the magnetic sensor 10
9 output changes are obtained. This is amplified by an amplifier 110 and output as the output of the detector.

No. 31-2] is a block diagram schematically showing the main parts of another embodiment of the present invention. In FIG. 3, 201 is set to 0.0 by external setting means. A correction signal generator that generates a predetermined positive or negative correction signal.

202 is an adder, and the same reference numerals as in FIG. 1 indicate the same or corresponding parts.

Now, when the switch 17 is not pressed, the movement is the same as in the embodiment of FIG. 1, but after the switch 17 is pressed,
When the output of the correction signal generating section 201 is 0, the above-mentioned first
Same as figure. However, when the output of the correction signal generating section 201 is positive, the input of the DC amplifier 13 is corrected to the positive side. Then, the above-mentioned negative foot pack loop works so that the value is the sum of the output of the detector lO or the value held in the memory 12 and the correction value, and the blade 16 moves to the corrected position and stops +h. .

Further, FIG. 4 is a block diagram schematically showing the main parts of still another embodiment of the present invention, and the same reference numerals as in FIG. 1 indicate the same or corresponding parts.

In FIG. 3, the output of DC amplifier 13 is inputted to adder 6 via switch circuit 9, and then inputted to DC amplifier 7. In this embodiment, since the DC amplifier 7 is always connected to the drive coil 14, only one DC amplifier with large drive power is required.
3 is! A small one with a small lK dynamic force is sufficient. Also in this embodiment, when the switch 17 is not pressed, the output of the smoothing circuit 5 is )&? f! The negative foot pack loop operates so that the pressure is equal to 8, and when the switch F is pressed, the output of the detector lO is corrected to the value held in the memory 12 by the output of the correction signal generator 201. The output of the brake coil 15 is 0 when the diaphragm is stopped, so the output of the brake coil 15 is 0 when the diaphragm is stopped, so it is in operation even when the switch 17 is pressed. has no effect.

In each of the embodiments described in E1 below, the detector is a combination of a detection magnet and a magnetic sensor, or, for example, a transmissive or reflective sensor using a phototransistor and an LED, or a proximity sensor using capacitance. Also good.

Further, although the memory is a combination of a capacitor and FET for capacity retention, a combination of a digital memory and a digital/analog or analog/digital converter, or another retention mechanism may be used. Furthermore, the correction signal generator and the switch may be linked together, and the diaphragm may not be mechanical but may be of another type or may be of liquid crystal or the like.

[Effects of the Invention] As described above, according to the present invention, the aperture can be controlled according to the output of the Wi image Hiroko, and the state of the aperture immediately before this control value can be maintained. Furthermore, it is possible to obtain an inexpensive video camera device equipped with an aperture mechanism that can correct the held state to an arbitrary value.

[Brief explanation of the drawing]

FIG. 1 is a block diagram schematically showing the main parts of an embodiment of the aperture control mechanism in the video camera device of the present invention, and FIG.
The figure is an explanatory view showing an outline of the mechanism of the main part of Fig. 1, and Fig. 3 is a block diagram showing an outline of the main part of another embodiment of the present invention. Figure S4 is a block diagram schematically showing the main parts of still another embodiment of the present invention. In the figure. l: Imaging lens 2: Aperture 3: Imaging element 4: Amplifier 5 Nido sliding circuit 6: Adder 7.1: l: DC amplifier 9, II: Switch circuit l Discharge detector] 2: Memory 11: Drive coil 15: Braking coil! 6 = Aperture blade 17: Switch 108: Detection magnet I0
9: Magnetic sensor 201: Correction signal generation section

Claims (1)

[Claims] A video camera device that converts a subject image into a video signal through a lens, an aperture, and an image sensor, includes a feedback system that controls the blades of an aperture to keep the video signal constant, and a feedback system that detects the position of the blades of the aperture. In order to have a detector and a memory that holds the latest output value of this detector or a value obtained by adding an arbitrary correction value to the output value, and to set the output value of the detector to the value held in the memory. 1. A video camera device comprising: a feedback system; and an aperture control mechanism that allows switching between the two feedback systems using a switch.