JPH07212636A - Television camera equipment - Google Patents

Abstract

PURPOSE:To control an optical passing quantity to an image pickup element when a strobo for the television camera is flashed. CONSTITUTION:A light passing quantity controller 15 is provided at a lens side 14 of a television camera 10. An AND gate 34 and a multivibrator 35 generate a pulse F synchronously with a vertical synchronizing signal of a television signal. A control circuit 37 flashes a strobo 39 depending on the pulse F and a control circuit 33 controls the light passing quantity of the light passing quantity controller only for a prescribed period.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television that controls the amount of light passing through an image pickup device in synchronization with the light emission of a strobe
Regarding a camera device.

[0002]

2. Description of the Related Art In a television camera, light from an object to be photographed irradiates an image pickup device such as a CCD through a lens to generate an electric signal according to the intensity of the light. Further, in synchronization with the vertical and horizontal synchronizing signals of the television signal, an electric signal is taken out from the image pickup device, and the synchronizing signal is added to the electric signal to generate a television signal. If the television signal is interlaced, 2 fields are 1
Since it becomes a frame, it takes two fields, that is, one frame time to obtain one image. When the subject is moving at high speed, the optical image on the image sensor changes during one frame, and the image reproduced from the output television signal is distorted. In particular, in the case of interlaced scanning, there is a time difference of about 1 field between adjacent scanning lines, so that the reproduced image is blurred.

In order to clearly photograph an object moving at high speed in this way, a shutter is attached to the lens side of the television camera, and the light of the object to be photographed is momentarily applied to the image pickup device. By opening the shutter only for a short period of time, a clear image can be obtained because an optical image at the moment the shutter is opened is formed on the image sensor even if the object moves at high speed.
However, since the shutter is momentarily opened, the light amount of the optical image on the image sensor is insufficient, and the reproduced image becomes dark as a whole. In order to improve this point, it has been proposed to illuminate the object to be photographed with a strobe in synchronization with the opening of the shutter.

By the way, since the illumination of the strobe has a high illuminance, the light image on the image pickup device may have an excessive amount of light. In this case, when the image is reproduced by the output signal from the television camera, the brightness is increased too much and the contrast is deteriorated. In order to prevent this, conventionally, the mechanical aperture of the television camera was adjusted to match the brightness.

[0005]

However, the mechanical diaphragm has a slow response speed and it is difficult to arbitrarily control the light amount. Therefore, it is difficult to reduce the light amount only when the strobe is emitting light and to return the light amount to the original amount after the strobe is finished emitting light. Further, the mechanical structure has a problem in its durability. Therefore, an object of the present invention is to provide a television camera device capable of arbitrarily controlling the amount of light passing through the image pickup device while the strobe is emitting light.

[0006]

The television of the present invention
The camera device is an electronically controllable light passage amount controller provided on the lens side of a television camera or on a strobe,
A pulse generating means for generating a pulse in synchronization with a vertical synchronizing signal of a television signal, a first control means for causing a strobe to emit light in response to a pulse from the pulse generating means, and a predetermined period according to the pulse from the pulse generating means. Second control means for controlling the light passage amount of the light passage amount controller to a predetermined value.

Further, in the television camera device of the present invention, the shutter provided on the lens side of the television camera and the light from the object to be photographed passes through the shutter for a desired period according to the pulse from the pulse generating means. And third control means for controlling the shutter so as to control the shutter.

[0008]

In the present invention, when the strobe emits light, the amount of light passing through the image pickup device of the television camera or the amount of light passing through the strobe from the subject is controlled to a predetermined value. It is possible to prevent the brightness of the light image on the device from rising extremely. Further, the brightness of the light image when the strobe is made to emit light in synchronization with the opening of the shutter and the brightness of the light image when normal shooting is performed without using the strobe and the shutter are made substantially constant. be able to. Therefore, even if the normal photographing is switched to the high-speed image photographing using the shutter and the strobe, the luminance of the reproduced image does not change. Therefore, even if the normal shooting and the high-speed shooting are sequentially repeated to record a series of shootings on the VTR, or even when observing with the finder, the brightness does not change due to the change in illumination by the strobe, and a natural state is obtained.

[0009]

1 is a block diagram of a preferred embodiment of the present invention. A lens member 14 is attached via a lens attachment member 12 to a light receiving portion of a television camera 10 having an image pickup device such as a CCD. The lens in the lens member 14 focuses the optical image of the object to be photographed on the image sensor. Further, in the lens member 14, an electronic aperture 15 which is a light quantity passage controller and an electronic shutter 16 such as a liquid crystal shutter are provided. In FIG. 1, the electronic diaphragm 15 and the electronic shutter 16 are arranged in this order from the image sensor side.
The order of the electronic diaphragm 15 and the electronic shutter 16 may be reversed. The configurations of the electronic diaphragm 15 and the electronic shutter 16 will be described later in detail.

The camera drive circuit 18 extracts an electric signal corresponding to the input optical image from the image pickup device of the camera 10 in response to the vertical and horizontal synchronizing signals from the synchronizing circuit 20, and adds the synchronizing signal to this electric signal. , A television signal is generated at the output terminal 22. The synchronizing circuit 20 generates vertical and horizontal synchronizing signals and supplies them to the camera driving circuit 18 in synchronization with an external synchronizing signal from the terminal 24 or independently of the outside, and also supplies a frame signal (or field 1). Vertical synchronization signal). Since the camera drive circuit 18 and the synchronization circuit 20 are similar to those of the conventional art, detailed description thereof will be omitted.

The shutter switch 26 includes a voltage divider 28.
The DC voltage from the circuit is selectively supplied to the clock terminal of the monostable multivibrator 30. Mode switch 32
Selects the output signal of the monostable multivibrator 30 or a positive voltage. The AND gate 34 is used for the synchronization circuit 20.
Receives the frame signal from the switch 32 and the output signal of the switch 32, and calculates the logical product of these signals by the monostable multivibrator 3
5 and 36 clock terminals. Therefore, the AND gate 34 operates as pulse generating means for generating a pulse in synchronization with the vertical synchronizing signal of the television signal.

The output signal of the monostable multivibrator 36 is supplied to the inverted clock terminal of the monostable multivibrator 38. These monostable multivibrators 35, 3
Since 6 and 38 use a variable resistor in the time constant circuit, the time constant is variable and the output pulse width can be adjusted. Further, while the monostable multivibrators 35 and 36 are clocked at the rising edge of the clock signal,
Note that the monostable multivibrator 38 is clocked on the falling edge of the clock signal. The output pulse of the multivibrator 38 is supplied to the shutter control circuit 40 to control the on / off state of the liquid crystal shutter 16.

The output pulse of the monostable multivibrator 35 is supplied to the diaphragm control circuit 33 and the strobe control circuit 37. This strobe control circuit 37 is triggered by the falling edge of the output pulse of the monostable multivibrator 35,
The strobe 39 is made to emit light for a predetermined period. The aperture control circuit 33 limits the amount of light passed by the electronic aperture 15 to a predetermined value while the strobe control circuit 37 is causing the strobe 39 to emit light. The light amount controller 31 sets this predetermined value. The diaphragm control circuit 33 and the controller 31 will be described in detail later. In addition, the light passage amount controller 15 is
Although not shown, instead of being provided on the lens 14 side, it should be noted that the amount of light to the image pickup device of the television camera 10 can be adjusted via the object to be photographed from the strobe 39 even if it is provided on the front surface of the strobe 39.

FIG. 2 is an operation waveform diagram of FIG. In FIG. 2, the waveform A is the output voltage of the switch 26,
Waveform B is the output voltage of monostable multivibrator 30, waveform C is the frame signal voltage from synchronization circuit 20, and waveform D is the output voltage of monostable multivibrator 36. Further, the waveform E is the monostable multivibrator 3
8 and the waveform F is the output voltage of the monostable multivibrator 35. The frame signal C is generated for each frame, that is, at time points T1, T3, ... When the mode switch 32 selects the monostable multivibrator 30, when the operator turns on the shutter switch 26 at time T2, the switch signal A is generated. The signal A causes the monostable multivibrator 30 to be clocked to generate the output signal B. The period of this output signal is at least one frame, and the shutter is operated by the frame signal next to the ON operation of the shutter switch 26.

The AND gate 34 allows the output signal B of the monostable multivibrator 30 to pass through the frame signal C during the high level period, so that the monostable multivibrator 3 is provided.
6 produces an output pulse D at time T3. The generation period T3-T4 of the output pulse D is variable. Further, the monostable multivibrator 38 is clocked at the trailing edge (falling edge) T4 of the output pulse D to generate an output pulse E having a variable width. Therefore, although the time points of the leading edge and the trailing edge of the output pulse E are synchronized with the frame signal C, they can be controlled arbitrarily.

The shutter control circuit 40 outputs the output pulse E
The electronic shutter 16 is controlled to turn on (open) the shutter only for a period corresponding to Therefore, when the shutter switch 26 is turned on, the electronic shutter 16 is turned on for a period determined by the time constants of the monostable multivibrators 36 and 38. Therefore, a clear still image can be obtained even for a fast-moving object to be photographed.

When the mode switch 32 selects the high level, the monostable multivibrator 36 is clocked for each frame signal C, so the electronic shutter 16 is also turned on for each frame signal. Therefore, a clear moving image can be obtained even for a fast-moving object to be photographed. In either case of the mode switch 32, the time constants of the monostable multivibrators 36 and 38 may be adjusted according to the light intensity and the speed of movement of the object to be photographed. That is, in the case of darkness or slow movement, the time constant is lengthened to lengthen the exposure time of the image sensor of the camera 10, and in the case of bright or fast movement the time constant is shortened to shorten the exposure time. .

Further, the monostable multivibrator 35 is
Clocked by the output pulse of AND gate 34, pulse F is generated. This output pulse F simultaneously controls the strobe control circuit 37 and the aperture control circuit 33. That is, during the period in which the strobe control circuit 37 causes the strobe 39 to emit light in synchronization with the frame signal to illuminate the object to be photographed, the aperture control circuit 33 causes the electronic aperture (light passage amount controller) to operate.
The amount of light to the image sensor can be reduced by controlling 15.

As described above, if the strobe light is illuminated by the strobe 39, the shutter opening time can be shortened, and an object moving faster can be photographed. At this time, the electronic diaphragm 15 can prevent the brightness of the strobe from being too high and the amount of light to the image pickup element of the television camera 10 from rapidly increasing. Further, since the electronic diaphragm 15 reduces the amount of light when the strobe emits light, the operating conditions of the stroboscopic illumination and the electronic shutter (the state of the amount of light to the image pickup element) can be the same as when the stroboscopic illumination is not performed. By adjusting the relationship between the time constants of the monostable multivibrators 35, 36, 38, the relationship between the strobe illumination timing and the shutter opening timing can be optimally controlled.

In the preferred embodiment of the present invention, the electronic shutter 16 is a liquid crystal shutter. Since this liquid crystal shutter has no movable mechanical part, its life is dramatically improved as compared with the mechanical shutter. A model explanatory view of the liquid crystal shutter 16 is shown in FIG. The polarization angles of the first polarization filter 82 and the second polarization filter 42 that form the liquid crystal shutter 16 differ by 90 degrees, for example. That is, the polarization filter 42 has a vertical transmission axis 46 and a horizontal absorption axis 48, and the polarization filter 82 has a vertical absorption axis 84 and a horizontal transmission axis 86.

The liquid crystal cell 54 acts as a variable optical delay device, and when an electric field is supplied, the liquid crystal cell 54
Allows the passing light to pass without rotating. Therefore, the light passing through the polarization filter 82 passes through the liquid crystal cell 54 as it is, so that the light is blocked by the polarization filter 42 and the shutter 16 is turned off. However, the liquid crystal cell 5
When the electric field is not supplied to 4, the light passing through the polarization filter 82 is rotated by 90 degrees in the liquid crystal cell 54, so that the light can pass through the polarization filter 42. That is, the shutter 16 is turned on. A π cell is suitable for the liquid crystal cell 54 in view of its operating speed, and it is disclosed in detail in JP-A-60-196728.

As described above, the dimming liquid crystal sheet is suitable for the electronic diaphragm 15. For example, the product name "ACT" developed and manufactured and sold by Ajinomoto Co., Inc. and Takiron Co., Ltd.
There is. This principle diagram is shown in FIGS. The light control liquid crystal sheet 15 has a structure in which a liquid crystal resin dispersion layer of a resin 154 and a liquid crystal 156 is sandwiched between transparent conductive films 150 and 152. The transparent conductive films 150 and 152 are supported by a polyester film (not shown).

When the diaphragm controller 33 applies an AC voltage between the transparent conductive films 150 and 152 to generate an electric field, the liquid crystals 156 are uniformly arranged in the direction of the electric field as shown in FIG. 156 and the resin 154 have the same refractive index, and the light from the transparent conductive film 152 side is transmitted and propagated to the transparent conductive film 150 side. That is, the light control liquid crystal sheet 15 becomes transparent.

On the other hand, when the diaphragm control device 33 does not generate an AC voltage, as shown in FIG. 5, due to the random arrangement of the liquid crystal 156, the refractive indexes of the liquid crystal 156 and the resin 154 do not match, and the incident light beam is scattered. . Therefore, the light control liquid crystal sheet 15 becomes opaque. Further, since the transparency of the dimming liquid crystal sheet 15 can be controlled by the value of the applied AC voltage, the transparency of the dimming liquid crystal sheet 15 can be arbitrarily controlled by controlling the value of the AC voltage by the light amount controller 31. it can.

During a period in which the pulse F from the monostable multivibrator 35 is not received, the diaphragm control device 33 supplies the maximum level AC voltage to the dimming liquid crystal sheet 15 in a transparent state, that is, the diaphragm is completely opened. Turn it on. However, while the monostable multivibrator 35 is generating the output pulse F, the AC voltage value supplied to the dimming liquid crystal sheet 15 is lowered to a desired value to bring the dimming liquid crystal sheet 15 into a desired translucent state. The amount of light passing therethrough, that is, the diaphragm is adjusted.
Therefore, it is possible to reduce the amount of light directed to the television camera 10 while the strobe 39 is emitting light.

FIG. 6 is an example of a circuit diagram of the aperture control circuit 33. The non-inverting input terminal of the operational amplifier 330 is grounded, and the AC generator 331 is connected to the inverting input terminal via the input resistor 332. Further, a variable resistor and a resistor 333 which are the light quantity controller 31 are provided at the inverting input terminal.
Is connected to the fixed contact of the analog switch 334. The movable contact of the analog switch 334 connects to the output terminal of the operational amplifier 330 and the primary winding of the transformer 335. The secondary winding of the transformer 335 is connected to the transparent conductive films 150 and 152 of the light control liquid crystal sheet which is the electronic diaphragm 15.

Since the analog switch 334 selects the variable resistor 31 when the output pulse F of the monostable multivibrator 35 is at a high level (during the stroboscopic light emission period), the operational amplifier 330 sets the AC voltage to an arbitrary voltage. Amplify to value. Further, when the output pulse F is at a low level (when the strobe does not emit light), the switch 334 selects the fixed resistor 333, so the operational amplifier 330 outputs a predetermined AC voltage at which the dimming liquid crystal sheet 15 becomes completely transparent. AC voltage generator 331 to generate
Amplifies the output of.

Although the preferred embodiment of the present invention has been described above, various modifications and changes can be made without departing from the spirit of the present invention. For example, the light quantity passing controller 15
Is the strobe 3 instead of the television camera 10 side.
It may also be provided on the front surface of 9. That is, by adjusting the amount of light passing from the strobe 39 to the object to be photographed, and adjusting the amount of light to the image pickup element of the television camera 10, the light amount passage controller 15 causes the television camera 1 to operate.
It can be the same as the one provided on the 0 side.

The light quantity passing controller 15 and the electronic shutter 16 may be provided outside the lens 14, or may be provided in the middle of the lens, on the side of the camera, or on the side opposite to the camera. Further, the flash emission timing, that is, the control timing of the light quantity passage controller and the shutter on timing can be controlled by using a programmable counter in addition to the monostable multivibrator. In this case, the output of the AND gate 34 causes the programmable counter to start counting and output pulses until the counting ends. Further, the light quantity passage controller may be an electronically controllable mechanical diaphragm instead of the dimming liquid crystal sheet. Furthermore, the relationship between the operation timing of the light quantity passing controller and the strobe is
Since it is sufficient that the light quantity passing controller operates before the strobe emits light, it does not have to operate at the same time.

[0030]

As described above, according to the present invention, when the strobe emits light, the amount of light passing through the image pickup device of the television camera or the light from the strobe is controlled to a predetermined value. Thus, it is possible to prevent the brightness of the optical image on the image sensor from extremely increasing. Further, the brightness of the light image when the strobe is made to emit light in synchronization with the opening of the shutter and the brightness of the light image when normal shooting is performed without using the strobe and the shutter are made substantially constant. be able to.
Therefore, even if the normal photographing is switched to the high-speed image photographing using the shutter and the strobe, the luminance of the reproduced image does not change. Therefore, normal shooting and high-speed shooting are sequentially repeated to record a series of shooting on the VTR,
Even when observing through the viewfinder, the brightness does not change due to the change in the lighting caused by the strobe, and the state becomes natural.

[Brief description of drawings]

FIG. 1 is a block diagram of a preferred embodiment of the present invention.

FIG. 2 is a signal waveform diagram illustrating the operation of FIG.

FIG. 3 is an explanatory diagram of an electronic shutter.

FIG. 4 is an explanatory diagram of a light amount passage controller.

FIG. 5 is an explanatory diagram of a light quantity passage controller.

FIG. 6 is a circuit diagram of a control circuit that controls the operation of a light quantity passage controller.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 television camera 14 lens 15 light quantity passage controller 16 electronic shutter 33 second control means 34 pulse generation means 37 first control means 40 third control means

Claims (5)

[Claims] 1. A television camera and a strobe, an electronically controllable light passage amount controller provided on the lens side of the television camera or on the front surface of the strobe, and synchronized with a vertical synchronizing signal of the television signal. Pulse generation means for generating a pulse, first control means for causing the strobe to emit light in response to the pulse from the pulse generation means, and the light passage for a predetermined period according to the pulse from the pulse generation means. A television camera device comprising: second control means for controlling the amount of light passing through the quantity controller to a predetermined value. 2. The television camera device according to claim 1, wherein the light passage amount controller is a dimming liquid crystal sheet. 3. A television camera and a strobe, an electronically controllable light passage controller provided on the lens side of the television camera or on the front surface of the strobe, and on the lens side of the television camera. An electronically controllable light passage amount controller and shutter provided, pulse generating means for generating a pulse in synchronization with a vertical synchronizing signal of a television signal, and the strobe according to the pulse from the pulse generating means. The first control means for emitting light, the second control means for controlling the light passage amount of the light passage amount controller to a predetermined value for a predetermined period according to the pulse from the pulse generation means, and the pulse generation means. A television controller including third control means for controlling the shutter so that light from the object to be photographed passes through the shutter for a desired period according to the pulse. Camera device. 4. The television camera device according to claim 3, wherein the light passage amount controller is a dimming liquid crystal sheet. 5. The first shutter is different in polarization angle from the first shutter.
4. The television camera device according to claim 3, further comprising: a second polarization filter; and a liquid crystal cell provided between the first and second polarization filters.