JPS6354877A - Exposure adjusting device for television camera - Google Patents

Abstract

PURPOSE:To provide a compact and light weighted device with no production of hunting or a flare by providing a liquid crystal iris for controlling the transparent and opaque areas of a liquid crystal according to an impressed voltage and executing a diaphragm adjustment and an image pickup element disposed at the back part of the liquid crystal iris and capable of adjusting the quality of charge by a video signal output. CONSTITUTION:The liquid crystal iris 10 is controlled in order to adjust the excessive deficit of the quantity of incident light to adjust the quantity of light. For instance, when it is required to set the liquid crystal iris 10 to an opening direction because the quantity of light is deficient, a switch 18 is connected to a terminal (c). Then, the voltage divided by a resistance (R1+R2+R3) and a resistance R4 is impressed to a driver 15, the voltage is impressed to the electrode part 12a1 of the electrode of 12a the liquid crystal iris 10 and a part opposite to the electrode part 12a1 of the liquid crystal 11 is opaque (slash part). Thereby, the title device is smaller, lighter and higher in a reliability for operation than the conventional device using an iris motor and is not stopped to more than a desired degree, so that the hunting or the flare or the like is not produced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an exposure adjustment device for a television camera such as a VTR, and particularly to an exposure adjustment device that uses a liquid crystal iris in combination with an image carrying element that can adjust the amount of charge by outputting a video signal. The present invention relates to an exposure adjustment device for a television camera that adjusts exposure.

BACKGROUND OF THE INVENTION FIG. 6 shows a block diagram of a conventional exposure adjustment device for a television camera. In the figure, light is transmitted through the zoom lens 1. Iris 2. The signal enters the solid-state image pickup device 4 via the master lens 3, is extracted therefrom as a video signal, and is extracted from the output terminal 6 via the amplifier 5. At this time, the output of the amplifier 5 is detected and rectified by the detector 7, and is used as a drive signal by the driver 8 to drive the iris motor 9, thereby operating the iris 2 and controlling it to obtain the optimum light amount.

Problems to be Solved by the Invention The above-mentioned conventional device uses the iris motor 9 when adjusting exposure, so it has a large volume, causes overlap, is expensive, and has no moving parts. Therefore, there was a problem that operation reliability was low. Furthermore, depending on the lighting, the aperture may be stopped down more than necessary, resulting in problems such as hunting and flare.

The present invention is small, lightweight, has high operational reliability, and
An object of the present invention is to provide an exposure adjustment device for a television camera that is free from the risk of hunting, flare, etc.

Means for Solving the Problems In FIG. 1, a liquid crystal iris 10 is a means for adjusting the aperture by controlling transparent and opaque areas of the liquid crystal according to applied voltage, and a solid-state image sensor 16 is provided after the liquid crystal iris 10. 3A and 3B are embodiments of an imaging means in which charge m can be adjusted by outputting a video signal.

The video signal output is controlled to a predetermined level by adjusting the charge amount of the solid-state image sensor 16 according to the video signal output, and the light amount is adjusted by controlling the transparent and opaque areas of the liquid crystal of the liquid crystal iris 1o. As a result, it is smaller, lighter, and has higher operational reliability than conventional devices using an iris motor, and since it is not narrowed down more than necessary, hunting, flaring, etc. do not occur.

Embodiment FIG. 1 shows a block system diagram of an embodiment of the apparatus of the present invention. In the figure, the same components as those in FIG. 5 are given the same numbers and their explanations will be omitted. In the figure, 10 is a liquid crystal iris,
It is provided between the zoom lens 1 and the master lens 3. The liquid crystal iris 10 has a configuration roughly shown in FIG.

In Fig. 2, 11 is a liquid crystal, and transparent electrodes 12a are placed on both sides of the liquid crystal.
, 12b are provided. For example, as shown in FIG. 3, the electrode 12a has four concentric electrode parts 12a+ to
It is divided into 12a4, and the electrode part 12a
The diameter of 1 to 12a4 is the aperture F2.8 (open) to F8, which will be described later.
The configuration is compatible with Electrode parts 12a1 to 12a
4 have lead wires drawn out from them, respectively, and are connected to a driver 15 in FIG. 1, which will be described later. Electrode 12b is electrode 12a
Not divided like. Note that 11' is a sealing part for the liquid crystal 11. 13a, 13b are glass, 14a, 14
b is a deflection plate, and is an electrode 12a.

They are provided on both side surfaces of 12b.

In FIG. 1, reference numeral 16 denotes, for example, a MOS type or CCD type solid-state image sensor, which is configured to be able to adjust the amount of charge using the detection output of the detector 7.

Here, solid carrier probe 16. Amplifier 5. In the loop of the wave detector 7, the amount of charge of the solid-state image sensor 16 is adjusted by the output of the wave detector 7, and the video signal output is controlled to a predetermined level. In this case, if the amount of incident light is sufficient, the video signal output will be 100%17, but if the amount of incident light is insufficient, the video signal output will not be 100%, and on the other hand, if the amount of incident light is excessive, the video signal output will be This will cause the signal to become too large, making it impossible to obtain signals at appropriate levels.

Therefore, it is necessary to control the liquid crystal iris 10 to adjust the light level. For example, the switch 17 is connected to the terminal M side to set the manual adjustment state. For example, if there is insufficient light and it is necessary to set the liquid crystal iris 10 in the open direction (for example, F4), the switch 18 is connected to the terminal C. As a result, a voltage divided by the resistor (R1+R2+R3) and the resistor R4 is applied to the driver 15, and in response, a voltage is applied to the electrode portion 12a1 of the electrode 12a of the liquid crystal iris 10, and the voltage is applied to the electrode portion 12a1 of the liquid crystal 11. The part facing the iris is opaque (hatched part), and the liquid crystal iris 10 is
The state shown in Figure (B) is reached.

Furthermore, when setting in the open direction (F 2.8), connect the switch 18 to the terminal d and apply zero ■ to the driver 15. 1o is brought into the state shown in FIG. 4(A).

In addition, when setting in the direction of narrowing down, for example, F5.
6 (@Fig. 4 (C)), connect the switch 18 to the terminal and apply voltage to the electrode portions 12a+ and 12az of the electrode 12a, and to obtain F8 (Fig. 4 (D)), connect the switch 18 to the terminal. 18 to the terminal a to connect the electrode part 12a of the electrode 12a.
A voltage is applied to 1 to 12a3.

As described above, since the device of the present invention has a configuration in which exposure is adjusted using both the solid-state image sensor 16 and the liquid crystal iris 10,
Compared to the conventional device that uses an iris motor to adjust exposure, it can be configured to be smaller and lighter in radius, and it is also lower in cost.Furthermore, since there are no moving parts, operational reliability can be improved, and it can be used at F8 or higher. Since it cannot be narrowed down, hunting, flaring, etc. do not occur as in conventional devices.

In this case, if only the liquid crystal iris 10 is used for adjustment, the operation speed is slow and there is a problem in response to aperture adjustment.
In the present invention, since the solid-state image sensor 16 is used in conjunction with the video signal output level adjustment, there is no particular problem in response.

Conversely, if only the video signal output level is adjusted by the solid-state image sensor 16, the depth of the image will be shallow when the depth of focus is constant; however, in the present invention, it is used in combination with the light amount adjustment by the liquid crystal iris 10. Therefore, this kind of problem does not occur.

On the other hand, if the switch 17 is connected to the terminal A side, an automatic adjustment state can be achieved. Color temperature detection signal from a color temperature sensor (R/G/B filter) provided near the light condensing diffuser plate 19 (reusing the color temperature sensor for auto white control used in current television cameras) is converted into a color temperature control signal by the amplifier 21 and taken out from the terminal 22, while it is converted into a control signal proportional to the illuminance level and sent to the controller 23.
supplied to The controller 23 has input/output characteristics shown in FIG. 5, and outputs a voltage according to a control signal proportional to the illuminance level. The output of the controller 23 is supplied to the driver 15, and as in the case described above, is supplied to each electrode part 12a1 to 72a4 of the electrode 12a, and the output is supplied to the liquid crystal iris 1.
The transparency and opacity of the liquid crystal 11 of 0 is controlled.

In this case, the midway (flat portion) of the stepped output in FIG. 5 is corrected by adjusting the charge m of the solid-state image sensor 16.

Note that it goes without saying that the color temperature sensor 20 may not be used and an illuminance detection sensor may be used.

Furthermore, if there is insufficient light when the exposure is adjusted using the solid-state image sensor 16, the amount of light is adjusted using the liquid crystal iris 10 as described above, and the AGC circuit (not shown) is also used.
Perform sensitivity correction. At this time, if the focal depth is to be withdrawn at a constant depth, the correction is made only by the AGC circuit.

Also, since the transmittance of liquid crystals can generally be controlled,
For example, the state of F4! 'i (Fig. 4(B)), the light D
If the amount is insufficient, the applied voltage to the electrode portion 12a1 of the electrode 12a may be varied to change the transmittance of the liquid crystal in this portion to bring it closer to a transparent state, thereby adjusting the light weight.

Furthermore, if the liquid crystal iris 1o is turned off to block light when the power is turned off, the solid-state image sensor 16 can be protected.

Effects of the Invention The device of the present invention is smaller, lighter, and less expensive than conventional devices using an iris motor, has no moving parts, and has high operational reliability. By setting the transparent and opaque areas of the liquid crystal as appropriate, the aperture shape can be freely and easily set, so unlike conventional devices, the aperture is not narrowed down more than necessary, eliminating hunting, flare, etc., and improving lens performance. It can be used in good condition and has the advantage of being able to perform so-called aperture-priority imaging, such as imaging with a constant F number and an aperture close to the maximum aperture to blur the background.

[Brief explanation of drawings]

FIG. 1 is a block system diagram of one embodiment of the device of the present invention, and FIG.
3 and 3 are respectively a schematic cross-sectional view of the liquid crystal iris and a schematic plan view of its electrodes, FIG. 4 is a diagram showing the aperture shape of the liquid crystal iris, FIG. 5 is an input/output characteristic diagram of the controller, and FIG. 6 is a conventional A block system diagram of an example of the device is shown. 6... Video signal output terminal, 7... Detector, 1o.
...Liquid crystal iris, 11...Liquid crystal, 12a, 12b.
...Electrode, 12a+ to 12a4...Electrode part, 15...
・Driver, 16... Solid-state image sensor, 17.18...
- Switch, 20... Color temperature sensor, 23... Controller. Patent applicant: Victor Japan Co., Ltd. Figure 1 Figure 2, Appearance - 12Q2 12CL3 Figure 4

Claims (1)

[Claims] It is characterized by having a liquid crystal iris that adjusts the aperture by controlling transparent and opaque regions of the liquid crystal according to applied voltage, and an image sensor that is provided after the liquid crystal iris and can adjust the amount of charge by outputting a video signal. Exposure adjustment device for television cameras.