JPH02281132A - Contamination detector - Google Patents

Abstract

PURPOSE:To detect contamination automatically by inputting light into a planar member which transmits the light, detecting the amount of the light propagating through the planar member, and detecting the degree of the contamination on the surface of the planar member based on the magnitude of the output. CONSTITUTION:When contaminants in the outer air stick to the surface of a planar member 13, light which is emitted from a light emitting element 16 and propagated through the inside of the member 13 is decreased in proportion to the degree of contamination. The light is inputted into a photodetector 17. When the electric output from the photodetector 17 is detected with a detecting part 19, the contamination of the member 13 can be automatically detected. When the signal from the detecting part 19 is received and a motor 15 is automatically driven, the contaminants stuck on the surface of the member 13 can be cleaned by using a wiper 14.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a dirt display device for a light transmission window used in a dustproof case of a television camera used in a dirty atmosphere for road monitoring, etc.

BACKGROUND OF THE INVENTION Conventionally, this type of dustproof case has been constructed as shown in FIG. In Figure 3, 1 is a surveillance television camera, 2
is a dustproof case, and 3 is a light transmission window.

4 is a wiper that cleans the light transmission window; 5 is a motor that drives the wiper 4; 6 is a hood that protects from direct rain and wind; and 7 is a stand that can change the direction of the television camera 1. In the same figure, dirt in the outdoor air.

In order to protect the television camera 21 and its lenses from dust, the television camera 1 is installed in a dustproof case 2, and monitors the outside world through a light transmission window 3. A wiper 4 was installed to clean the area.

Problems to be Solved by the Invention In such a conventional configuration, even though the television camera 1 is protected from dirt in the outside air, the light transmission window 3 of the dustproof case 2
is always affected by dirt in the outside air, so as soon as the surveillance image from the television camera 1 becomes unclear when visually inspected, the wiper 4 must be manually operated to clean the surface of the light-transmitting window 3. There were drawbacks.

The present invention solves these problems.

The object of the present invention is to provide a dirt detector that automatically detects dirt on a light transmission window.

Means for Solving the Problems In order to solve this problem, the present invention provides a light emitting element that allows light to enter from the outside into a plate member that constitutes a light transmission window of a dustproof case, and a The contamination detector is provided with a light receiving element that detects the light from the light emitting element that has propagated, and a detection unit detects an electrical output proportional to the amount of light incident on the light receiving element, thereby forming a dirt detector.

Effects of the present invention With the above-described configuration, the light emitted from one light emitting element propagates inside the plate-shaped member while repeating total reflection on both planes, so if there is dirt on the plane of the plate-shaped member, it will be totally reflected. Light is absorbed by the dirt.

Alternatively, the light is diffusely reflected and the amount of light propagating inside the plate member is reduced. Therefore, by detecting changes in the amount of light with a light receiving element, dirt on the surface of the plate member can be detected.

It can detect the degree of dirt and dirt, and functions as a dirt detector.

Embodiment FIG. 1 is a block diagram of a dirt detector according to an embodiment of the present invention. In this patent specification, the same numbers in each figure indicate the same members.

In FIG. 1, 11 is a surveillance television camera.

12 is a dustproof case in which the television camera 11 is installed;
Reference numeral 13 denotes a plate member such as a glass plate that constitutes a light transmission window; 14 a wiper for cleaning dirt on the surface of the plate member 130; 15 a motor that drives the wiper 14; A light emitting element that allows light to enter inside, 1
7 is a light receiving element that detects the light from the light emitting element 16 that has propagated inside the plate member 13; 18 is a light receiving element that detects only the light that has propagated inside the plate member 13 and blocks other light; A shielding plate that shields the periphery of the element 17, 19 is a light receiving element 17
This is a detection unit that detects the electrical output of the

The television camera 11 is provided inside surrounded by a dustproof case 12 and a plate member 13, and is protected from dirt in the outside air. The television camera 11 monitors the outside world through the light transmission window of the plate member 13, but since one surface of the plate member 13 is in contact with the outside world, dirt from the outside world adheres to that surface. .

Detection of dirt on the plate-shaped member 13 will be explained using the main part explanatory diagram of FIG. 2. In FIG. 2(a), the light emitting element 1
The light 20 emitted from the plate member 6 enters the inside of the plate member 13 from the end face of the plate member 13 . This light propagates through the plate member 13 while repeating total reflection at the boundary between the plate member 13 and the air layer 23, and enters the receiver 67.7 optical element 17.

When dirt 22 adheres to the surface of the plate-like member 13 (1) as shown in FIG.
The light 2o that propagated through the plate member 13 while undergoing total reflection 7 times at the boundary between the plate member 13 and the air layer 23 is reflected by the dirt 2.
As a result, the amount of light reaching the light receiving element 1 is reduced. Further, the amount of light reaching the light receiving element 1T decreases in proportion to the degree of dirt adhering to the surface of the plate member 130. Here, shielding plate 1
8 is provided so as to cover the periphery of the light receiving element 17.

It has a function of detecting only the light 21 propagated inside the plate member 13 and blocking the light of that song. Also, a light receiving element 17 that detects only light of a specific wavelength or light in a specific wavelength range
If used, it has the ability to distinguish between light from the luminescent confectionery and light incident from outside.

Returning to Figure 1 again, the explanation will continue. When dirt in the outside air adheres to the surface of the plate-like member 13, the light emitted from the light emitting element 7 and the light propagating inside the plate-like member 13 decreases in proportion to the degree of dirt, and the light received incident on element 17. Therefore, by detecting the electrical output of this light receiving element 1 with the detection section 19.

The degree of contamination of the plate member 13 can be automatically detected.

Furthermore, upon receiving the signal from this detection section 19.

If the motor 15 is automatically driven, the wiper 14 can be used to clean dirt adhering to the surface of the plate member 13.

This configuration is characterized by a light emitting element 16 that allows light to enter from the outside into the plate member 13 that constitutes the light transmission window of the dustproof case 12, and a light emitting element 16 that allows light to enter the plate member 13 that forms the light transmission window of the dustproof case 12. A detection unit 19 is provided with a light receiving element 17 that detects light, and an electric output proportional to the amount of light incident on the light receiving element 17 is provided.
It is detected by

As described above, in one embodiment of the present invention, the detection unit is used to
The degree of dirt attached to a plate-shaped member can be detected by the amount of light propagating through the plate-shaped member, so dirt can be automatically detected.
Furthermore, if the wiper is driven by a signal from the detection section, the surface of the plate-like member can be automatically cleaned depending on the dirt, thus functioning as an excellent dirt detector.

In addition, if the above-mentioned plate member is used as a light-transmitting window, an excellent dustproof case that automatically detects and cleans dirt can be constructed.If a TV camera is installed inside this dustproof case, it can be used outdoors where the air is heavily polluted. Demonstrates excellent functionality as a surveillance camera.

In addition, in this example, the light emitting element that makes light enter the inside of the plate-like member and the light-receiving element that detects the light propagated inside the plate-like member are each explained as one piece, but the size of the plate-like member You may use more than one depending on the situation.

In addition, in the drawings of this embodiment, it has been explained that light is made to enter from the end face of the plate-like member and the light from the end face is detected. For example, one means of light incidence and detection direction is not mentioned.

Furthermore, in this embodiment, the detection of dirt on one side of the plate-shaped member has been described, but it goes without saying that the same effect can be obtained even if dirt is detected on the other side.

Effects of the Invention According to the present invention, light is incident on the inside of a light-transmitting plate-like member, the amount of light propagating through the plate-like member is detected by the production unit, and the output of the light is detected. Since the degree of dirt on the surface of the plate member can be detected from the size, the effect of automatically detecting dirt can be obtained.

It is possible to provide a dirt detector that is one bite better than the conventional one.

In addition, if the wiper provided on the surface of the plate-shaped member is driven by the signal from this detection unit, the surface of the plate-shaped member can be automatically cleaned or banded depending on the dirt, and functions as an excellent dirt detector. It has the effect of

Furthermore, if the plate member is used as a light transmission window.

You can configure an excellent dustproof case that automatically detects and cleans dirt, and if you install a TV camera inside this dustproof case,
It provides excellent functionality as an outdoor surveillance camera where the air is highly polluted.

[Brief explanation of drawings]

FIG. 1 shows a contamination detector according to an embodiment of the present invention.
2. FIG. 2 is an explanatory diagram of the main parts of the embodiment shown in FIG. 1, and FIG. 3 is an explanatory diagram of a dustproof case for explaining conventional dirt detection. 11...Television camera, 12...Dust-proof case 13...Plate member that transmits light, 14.
...Wiper, 15...Motor, 16...
...Light emitting element, 17... Light receiving element, 18...
- Shielding plate, 19...detection section. 20.21...Arrow showing light, 22...
- Dirt. 23...Air layer. Name of agent: Patent attorney Shigetaka Awano and one other person
2 range ≦ Ugly 1 range

Claims (4)

[Claims] (1) A plate-like member that transmits light and has at least one surface in contact with an air layer, a light-emitting element that allows light to enter the inside of the plate-like member, and a light-emitting element that emits light from the light-emitting element, A light-receiving element detects the light propagated in the plate-like member while redirecting total reflection at the boundary between the surface of the plate and the air layer, and the magnitude of the electrical output of the light-receiving element indicates that the surface of the plate-like member is contaminated. A dirt detector comprising: a detection section that detects the degree of dirt. (2) The dirt detector according to claim 1, further comprising a wiper for cleaning the surface of the plate-like member, and the wiper is operated by a signal from the detection section. (3) The dirt detector according to claim 1, wherein the light receiving element detects only light of a specific wavelength or a specific wavelength range. (4) The dirt detector according to claim 1, characterized in that the area around the light receiving element is shielded so that only the light propagated inside the plate member is detected and other light is blocked. .