JPS60134673A - Monitor camera - Google Patents

Abstract

PURPOSE:To increase speed of response from detection of light to stopping down and prevent burning of an image pickup tube by providing an intensity of illumination detecting element near the entrance of light and providing a filter for preventing burning having a liquid crystal part that changes smount of transmission of light responding to the detection output in front of a monitor camera. CONSTITUTION:The intensity of illumination detecting element 2 is provided near the entrance 4 of light and the filter 3 for preventing burning is provided in front of the entrance 4 of light. The filter 3 has a liquid crystal part 9 at the center. It is divided into sections and each can be controlled separately, and passing of light is controlled by application of an electric field. When light near the light entrance 4 is detected by the intensity of illumination detecting element, the detection output is A/D converted and digital converted and each section is controlled separately. However, for instance, when the light entrance 4 is exposed to direct sunlight, all sections of the liquid crystal part 9 is made opaque by an intensity of illumination detection controlling circuit 5 and burning is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a surveillance monitor camera installed outdoors.

[Background technology]

Conventionally, monitor cameras installed outdoors for surveillance use a built-in image pickup tube that operates a mechanical aperture mechanism using the output from a photoresponsive element to prevent it from being burned by direct sunlight, etc. The input intensity of the light was a sub-adjustment. In conventional monitor cameras like this, the response speed of the mechanical aperture is slow, and for example, when sunlight momentarily overlaps and enters the monitor camera due to a car mirror, the aperture mechanism cannot prevent this. There were drawbacks. In addition, mechanical aperture mechanisms often have the disadvantage of being complicated and large, and having a short lifespan.

[Purpose of the invention]

The present invention has been made focusing on the above-mentioned problems,
The purpose of the present invention is to obtain a monitor camera that has a fast response speed from light detection to aperture, is effective in preventing image pickup tube burn-in, and is compact and has a long lifespan.

[Disclosure of the invention]

In the present invention, an illuminance detection element is provided near the entrance of the monitor camera, and an anti-burning filter having a liquid crystal part that changes the amount of light transmitted in response to the output of the illuminance detection element is provided on the front surface of the monitor camera. The liquid crystal section is divided into a plurality of sections that can be individually controlled. 1-1 The illuminance detection regulator output is digitally converted and code converted, and each section is individually controlled to transmit light using the coded signal. By changing from the state to the opaque state, seizure of the tube was prevented.

Embodiments of the present invention will be explained below with reference to FIGS. 1 to 3. The present invention is a monitoring camera 1 mainly installed outdoors, and is provided near an illuminance detection element 2t and a light entrance 4 for detecting the intensity of external light. On the other hand, the anti-burning filter 3 prevents the image pickup tube of the monitor camera 1 from being burnt.
is arranged in front of the light input [4]. This anti-seize filter 3 has a liquid crystal section 9 in the center, and is divided into a plurality of sections 10.degree., 10. . . , each of which can be individually controlled. The molecular orientation of the liquid crystal is controlled by applying an electric field to the external processing O of the liquid crystal section 9, which is divided into sections 10, 10, . . . , so that light can pass through or be blocked by the light control plate. The liquid crystal section 9 is controlled by the illuminance detection control circuit 5 for each section 10, 113, . 1 in any n of opaque state
7) The 3 illuminance detection control circuit 5 is composed of three circuits. First, the illuminance detection circuit 6 converts the output of the illuminance detection element into an amplified analog signal VC as a valid control signal, and the illumination If
An A/D conversion circuit converts the analog output of the I injection circuit 6 into a digital signal, and a code conversion circuit 8 converts the digitally converted signal into a coded signal that can be controlled for each valley section of the liquid crystal section 9. It is composed of Eri. Each section 10, 10 of the liquid crystal section 9 is made to become opaque one after another from the one closest to the outside of the circle.

Next, the operation will be explained. In situations where the outdoor illuminance where the monitor camera l is installed is not so high that it does not cause any bad effects such as burn-in on the picture tube, each section 10, 10, etc. of the liquid crystal section 9 is completely closed. It is in a state where light is transmitted. Next, for example, when the VC is set such that direct sunlight hits the vicinity of the light entrance 4 of the monitor camera l, the illuminance detection element detects this and detects the illuminance detection port #! The code conversion circuit 7 converts the signal into a digital conversion field, and the code conversion circuit 8 converts it into sections io, io...(1 to 2).
1) are individually controlled. For example, sections N0123 and 4°9
．． 14 and 8.13.18 and 19, 20.

21 remains in a non-transmissive state, and the remaining sections are in a transparent state, so that the overall 1cld light incident stitch is somewhat reduced. Next, for example, if direct sunlight from the sun hits the light entrance 4 and light reflected from a car mirror enters the light entrance 4, then
Normally, the quaternary tube is at great risk of being burnt out, but in this case, all sections of the liquid crystal section 9 become opaque to prevent burn-in.

The time it takes to reach this non-transparent state is much faster than conventional mechanical devices, since they all have a drowsy structure.

In the present invention, each section of the liquid crystal section 9] 0, 10... is configured to change between two states, a fully transparent state and an opaque state. Good too.

〔Effect of the invention〕

As described above, according to the present invention, an illuminance detection element is provided near the entrance of the monitor camera (C5), and a liquid crystal part is provided that changes the transmitted sound of light in response to the ejection output of the illuminance detection element. The monitor camera configuration is characterized by having an anti-burn filter placed in front of the image pickup tube of the monitor camera, so it is possible to detect illuminance even if the intensity of light entering the light entrance of the monitor camera is suddenly 1'°C. Detection with element 1-1' Since the liquid crystal part is made opaque to light with a fast response speed,
Compared to mechanical apertures, liquid crystal apertures are more effective in preventing image-tube seizure, and as a result, miniaturization and longer lifespans have been achieved.

[Brief explanation of drawings]

Figures 1 to 3 show the implementation of the present invention; Figure 1 is a perspective view of a monitor camera; Figure 2 is an electrical circuit diagram; and Figure 3 is a front view of the liquid crystal section.・Monitor camera, 2... illuminance detection element, 3.
...Anti-seize filter, 4...Light entrance, 7...A
/D conversion circuit, 8... code conversion circuit, 9... crystal section, 1o... section. (6)

Claims (1)

[Scope of Claims] l) An illuminance detection element is provided near the entrance of the monitor camera, and an anti-burning filter equipped with a liquid crystal part changes the light transmission mt in response to the detection output of the illuminance detection element. A monitor camera characterized by being installed in front of the image pickup tube of the monitor camera. 2) A converting changes in the output of the illuminance detection element into digital values
/D conversion circuit, a code conversion circuit for encoding digital values, and a coded signal to selectively change each section of the liquid crystal section divided into control sections from a light transmitting state to a non-light transmitting state. A monitor camera featuring: