JPH05328210A - Led lighting device for television camera - Google Patents

Abstract

PURPOSE:To obtain the video image of a moving picture similar to that under lighting using an electric bulb by pulsating an LED synchronously with the shutter operation of a television camera. CONSTITUTION:The LED lighting device 14 is made up of a field selection circuit 2 switching a field with a lighting synchronization mode selector switch 4, a counter circuit 6 frequency-dividing the frequency according to a shutter time set from a setting switch 7, an automatic tracking circuit 8 automatically setting a lighting timing of the LED 10 and a lighting time traces by the drive timing from the counter circuit 6, an AND gate circuit 5 operating a field signal from a field selection circuit 2 and the lighting signal from the automatic tracking circuit 8 and outputting the operated signal to a drive circuit 9 of the LED 10. Then the LED 10 is driven relatively in the shutter operating timing of the television camera 1 and the image pickup is executed by lighting the object 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LED lighting device for a TV camera, which is used when shooting indoors or at night in a moving image shooting system using a TV camera.

[0002]

2. Description of the Related Art Conventionally, as a lighting device for photographing an image of a room or night by a television camera, a continuously lighted bulb or a strobe which emits light in conjunction with a shutter operation of the television camera is used as a light source. , The former has shortcomings such as short life and large power consumption, and the latter also has short life, and in high-speed repeated light emission, the amount of light for each light emission is uneven, making it difficult to adjust the amount of light. It had a defect such as

When shooting a moving image using a shutter camera such as a television camera, it is necessary to match the shutter timing with the flash emission timing. However, due to the light emission principle of various strobes currently in use, it is difficult to set a delicate timing, so generally, the shutter time is lengthened so that the strobe light emission time falls within the opening time. Therefore, this method has a drawback that the exposure time becomes the stroboscopic light emission time, the sampling interval is not stable, and the exposure amount is not stable when photographing a high-speed moving object.

[0004]

The present invention has been devised in view of the above problems, and (1) obtains a moving image similar to continuous illumination using a light bulb. (2) Stabilize the exposure amount (exposure time). (3) Stabilize the LED emission timing. (4) Automatically follow the deviation of the shutter timing and the variation of the LED light emission time that occur when the shutter time is changed, and always maintain the optimum light emission condition. (5) By making the LED emit light for each field,
Equivalently double the amount of light is obtained. (The light emission current of the LED can be doubled.) (6) The LED light source is used to simplify the light amount adjustment (adjust the light emission current). (7) Use an LED light source to save power. (8) The LED light source is used to extend the life of the device. It is an object of the present invention to provide an LED lighting device for a television camera that can be used.

[0005]

In order to achieve the above object, an LED lighting device for a television camera according to the present invention is characterized in that an LED is pulsed in synchronization with a shutter operation of the television camera. is there. That is, the LED illuminating device for a television camera according to the present invention is such that an LED is pulsed in synchronization with either one of the odd field and the even field of the video signal, or both fields. is there.

[0006]

According to the above structure, the emission current is reduced to 2 by causing pulse emission for each field of the television camera.
Since it can be doubled, the amount of light can be doubled as compared with the method of emitting light in both fields. Further, since the timing of pulsed light emission is synchronized with the shutter timing by counting the horizontal synchronizing signal in the video signal, shutter photographing can be performed at stable timing.

When the shutter time is changed, the light emission timing and light emission time of the LED are automatically made to follow it. Since the pulse emission time is set to be longer than the shutter time and the shutter priority exposure method is used, it is possible to shoot with a stable exposure time.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an LED lighting device for a television camera according to the present invention will be described below with reference to the drawings. Figure 1 LE
FIG. 3 is a block diagram of a state in which the D illumination device is combined with a CCD camera, which will be described with reference to the signal timing chart of FIG. 2.

As the television camera 1, a CCD type camera is generally used, and a frame transfer type CCD camera will be described as an example. In the description of the present embodiment of FIG. 1, the case where the synchronizing signal is used is shown, and the television camera 1 performs the video operation by the vertical synchronizing signal VD and the horizontal synchronizing signal HD from the image processing device 11, Video signal S to the image processing device 11
Is output.

The LED lighting device 14 of the present invention comprises a field selection circuit 2 for switching fields by means of a light emission synchronization mode selection switch 4, a counter circuit 6 for frequency division according to a shutter time set by a setting switch 7, and the counter circuit. LE to follow the drive timing from 6
An automatic follow-up circuit 8 for automatically setting the light emission timing and the light emission time of D10, and an AND for calculating and outputting the field signal from the field selection circuit 2 and the light emission signal from the automatic follow-up circuit 8 to the drive circuit 9 of the LED 10. It is composed of a gate circuit 5. Then, the LED 10 is driven to emit light relative to the shutter operation timing of the television camera 1 to illuminate the subject 13 and perform photographing.

The field selection circuit 2 has a function of selecting an odd field and an even field from the image processing apparatus 11, and sets which field the LED 10 emits in synchronization with the setting switch 3. Then, the light emission synchronization mode selection switch 4 selects "light emission in all fields" or "light emission in one field".

FIG. 2E shows the all-field light emission synchronization mode, in which a level signal for enabling light emission is input to the input terminal of the AND gate circuit 5, and the vertical synchronization signal VD of FIG. 2B is input. It emits light in synchronization with all of.

FIG. 2 (f) shows the one-field light emission synchronization mode, in which the AND gate circuit 5 has an input terminal as shown in FIG. 2 (b).
The field signal of FIG. 2 (c), which makes it possible to emit light only in the odd fields of the vertical synchronizing signal VD, is input, and light is emitted in synchronization only in the odd fields.

FIG. 2D shows the shutter operation of the television camera 1, and the shutter time can be set to an arbitrary time by the setting switch 7.

Further, the automatic tracking circuit 8 includes a setting switch 7
With the function to automatically follow the light emission timing and light emission time of the LED 10 with respect to the time set in
Figure 3 shows the shutter and L when the shutter time is changed.
6 is a timing chart showing the relationship of the ED light emission operation.
With this automatic tracking circuit 8, a short shutter time (see FIG.
The operation of the light emission signal with respect to (b)) (see FIG. 2 (c)), and the light emission timing of the LED 10 (see FIG. 2 (e)) when a long shutter time (see FIG. 3 (d)) is set, It is shown that the relationship of the light emission time of the LED 10 (see FIG. 3E) automatically follows.

On the other hand, in order to synchronize the shutter operation of the television camera 1 and the light emitting operation of the LED 10, the horizontal synchronizing signal HD (see FIG. 2A) sent from the image processing apparatus 11 is digitally converted by the counter circuit 6. Since it counts, it operates at accurate timing. (In the past, the timer was an analog timer.) Further, the light emission timing t1 is set to be a time earlier than the shutter is released, and LED1 is set.
This prevents the light emission timing of 0 from being delayed and resulting in insufficient exposure.

Further, the drive circuit 9 has a current amplification function for obtaining a drive current required for the LED 10, and emits the pulse drive light of the LED 10 by the light emission signal from the AND gate circuit 5. The LED 10 has a structure that takes into consideration the wavelength sensitivity characteristics of the television camera and the number of wavelengths that are selected according to the purpose of use to obtain the required amount of light, and the light distribution characteristics that match the size of the subject 13.

The present invention separates the vertical sync signal and the horizontal sync signal from the video signal (composite signal) S of the television camera by using the sync separation circuit 12 as shown by the dotted line in FIG. By setting the timing, it is possible to realize the same function as in the above embodiment. Further, in the embodiment shown in FIG. 1, the LED 10 part and the electronic circuit are housed in an integrated housing.
It goes without saying that it is possible to separate the parts so as to face the subject 13.

[0019]

Since the LED lighting device for the television camera according to the present invention is configured as described above, the LED lighting device is used as a light source.
By adopting a structure in which the light emission is driven in synchronization with the vertical and horizontal synchronizing signals from the image processing device which drives the television camera or the composite signal from the television camera, (1) lighting using a light bulb A similar moving image can be obtained. (2) The exposure amount can be stabilized. (3) The light emission timing can be stabilized. (4) The light amount adjustment can be simplified. (5) Power can be saved. (6) The life can be extended. (7) By causing the LED to emit light for each field of the television camera, it is possible to equivalently obtain twice the amount of light. The advantages obtained by implementing the present invention are extremely large.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an LED lighting device for a television camera according to the present invention in a state in which an LED lighting device is combined with a CCD camera.

FIG. 2 is a signal timing chart of the same device.

[Fig. 3] Shutter and L when the shutter time is changed
6 is a timing chart showing the relationship of the ED light emission operation.

[Explanation of symbols]

 1 TV camera 2 Field selection circuit 3 Setting switch 4 Light emission synchronization mode selection switch 5 AND gate circuit 6 Counter circuit 8 Automatic tracking circuit 9 Drive circuit 10 LED 11 Image processing device 12 Sync separation circuit 13 Subject 14 LED lighting device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Etsuo Iida 100 Maeda-cho, Totsuka-ku, Yokohama-shi, Kanagawa Koito Industry Co., Ltd.

Claims (1)

[Claims] 1. An LED lighting device for a television camera, wherein the LED emits a pulse light in synchronization with a shutter operation of the television camera.