JPS6047571A - Video camera device - Google Patents

Abstract

PURPOSE:To detect the beam deterioration of an image pickup tube automatically and increase the beam amount automatically by detecting the signal level where a quantity of light is incident to the image pickup tube, and varying the electrode voltage of the image pickup tube automatically according to the variation in the signal level with time. CONSTITUTION:The signal level 112 in a range 102 scanned in the normal scanning period of the face plate 101 of the image pickup tube 201, and the signal level 111 of the optical black part 13 and the signal level 113 of a part 104 except in the range scanned in the normal scanning period are detected. Then, variation in signal level (a) of the signal level 112 out of the signal levels 111, 112 and 113 is detected, and this variation in signal level (a) is regarded as the beam deterioration of the image pickup tube 201. Then, the variation in the beam signal (a) is amplified by the signal level amplifier 202 of a video camera device and applied to the 1st grid voltage varying circuit to vary the electrode voltage of the image pickup tube 201, increasing the beam amount automatically.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a video camera device.

Conventional configurations and their problems Conventionally, in video camera devices using image pickup tubes, the lifespan of the image pickup tube is determined by the beam deterioration (reduction in emissions) of the image pickup tube. ~2000H was the limit.

When used as a surveillance camera, extending the lifespan is a very important issue from a practical standpoint, but this problem has not yet been resolved. On the other hand, even with current image pickup tubes, the beam output is increased at the beginning of beam deterioration.
By changing the grid voltage, it is possible to temporarily extend the practical period, that is, the service life.
Resetting the grid voltage has traditionally relied on manual methods. This poses practical adjustment difficulties, especially when the image pickup tube is used in a surveillance camera.

Purpose of the Invention The present invention eliminates the problems of the above-mentioned conventional example,
This system automatically detects beam deterioration of the image pickup tube and also automatically increases the beam amount.

Structure of the Invention In order to achieve the above object, the present invention scans a portion other than the normal scan (a portion always exposed to a constant amount of light) in the same manner during the vertical deflection period to the image pickup tube. 3. - The beam amount is changed by detecting the change in the scanning signal level in this part and changing the first grid voltage of the image pickup tube.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1, 2, and 3.
This will be explained in detail using figures.

FIG. 1 is a view of the image pickup tube viewed from the face plate side, where 101 is the face plate of the image pickup tube, 102 is the range scanned within the regular scanning period, and 103 is the optical black area (0
104 indicates a portion outside the range scanned within the normal scanning period. FIG. 2 shows the output waveform of the image pickup tube, where 111 is the signal level of the optical black part, 112 is the scanning signal level within the normal scanning period, and 113 is the part outside the range scanned within the scanning period. 104 is the output signal level of the image pickup tube.

FIG. 3 is a block diagram of the main parts of a video camera device according to an embodiment of the present invention, in which 201 is an image pickup tube;
Reference numeral 2 denotes an amplifier that amplifies the amount of change in signal level at a portion into which a fixed amount of light is incident, 203 a first grid voltage variable circuit of the image pickup tube, and 204 a first grid.

In the above configuration, by keeping the scanning portion 104 on the image pickup tube always exposed to a constant amount of light, the signal level a does not depend on changes in the subject, as shown in FIG. , the change in signal level a appears to be due to a change (deterioration) in the beam amount. When this signal level a reaches a level below the setting conditions (such as the surrounding environment), the first grid voltage variable circuit 203f, which is preset according to the level,
By changing (increasing) the voltage of the first grid 204 of the image pickup tube 201, the beam amount is increased.

Effects of the Invention The present invention has the above-mentioned configuration, and automatically detects the deterioration of the beam amount and automatically increases the beam @.As a result, the usage period of the image pickup tube is extended, and especially maintenance is required. It is effective for use in surveillance cameras that require maintenance.

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[Brief explanation of the drawing]

Fig. 1 is a diagram of an image pickup tube used in an embodiment of the present invention viewed from the face plate side, Fig. 2 is an output waveform diagram of the image pickup tube, and Fig. 3 is a block diagram of the main parts in an embodiment of the present invention. It is a diagram. 201... Image pickup tube, 202... Signal level amplifier, 203... First grid voltage variable circuit, 204... First grid electrode. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
figure

Claims (2)

[Claims] (1) Provide a part into which a certain amount of light enters the image pickup tube, detect the signal level of the part where the certain amount of light enters, and automatically adjust the electrode voltage of the image pickup tube according to the temporal change in the signal level. A video camera device characterized in that the video camera device is configured to change the direction of the video camera. (2) The video camera device according to claim 1, wherein the signal level is detected from the output of the image pickup tube.