JPH0894438A - Infrared sensor - Google Patents

Abstract

PURPOSE: To provide an infrared sensor whose detection performance of infrared rays is high and whose detection region of the infrared rays is wide. CONSTITUTION: The main constitution part of an infrared sensor 1 is provided with an infrared lens 3 and with an infrared detection part 4. The infrared lens 3 takes into infrared rays radiated from a heat source 8, and its forms the infrared image of the heat source 8 on a three-dimensional curved-surface image-formation face due to the astigmatism of the infrared lens 3. The three- dimensional light-receiving face of the infrared detection part 4 is formed by combining and arranging a plurality of sensor element substrates 6 along the three-dimensional curved-surface image-formation face. A plurality of infrared sensor elements 5 which detect and output infrared detection signals according to the irradiation amount of the infrared rays are arranged and installed in a two-dimensional array shape on the substrates 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared sensor used for fire alarms, crime prevention devices and the like.

[0002]

2. Description of the Related Art FIG. 4 shows a schematic configuration example of a conventional infrared sensor 1 used by being incorporated in a system such as a fire alarm or a crime prevention device. The infrared sensor 1 includes an infrared lens 3 and an infrared detecting section 4.

The infrared lens 3 takes in infrared rays (heat) radiated from a heat source 8 such as a fire or a person in the infrared detection area, and irradiates and forms an infrared image of the heat source 8 on the light receiving surface of the infrared detecting section 4. It is a thing.

The light receiving surface of the infrared detecting section 4 is formed by a flat sensor element substrate 6 on which a plurality of infrared sensor elements 5 for detecting the applied infrared rays are arranged in a one-dimensional or two-dimensional array. There is. The infrared sensor element 5 is formed by a pyroelectric element that causes spontaneous polarization according to the infrared irradiation amount, a thermopile that generates an electromotive force according to the infrared irradiation amount, or a bolometer whose thermal resistance changes according to the infrared irradiation amount. Then, an infrared detection signal corresponding to the amount of infrared rays emitted is detected and output.

The infrared sensor 1 includes each infrared sensor element 5
The infrared image of the heat source 8 on the light receiving surface of the infrared detecting section 4 is detected based on the infrared detection signal.

[0006]

However, when infrared rays are radiated from the heat source 8 and irradiate the light-receiving surface of the infrared detection section 4 through the infrared lens 3, the infrared lens 3 is used as follows. Astigmatism or the like occurs, and the infrared image of the heat source 8 is not formed on the flat sensor element substrate 6, but an image is formed on a curved surface (solid curved image forming surface) as shown by a dotted line in FIG. Tie

For example, as shown in FIG. 5A, it is assumed that the infrared rays emitted from the heat source 8 enter the point C of the infrared lens 3 from a direction forming an angle θ with the optical axis of the infrared lens 3. Here, a plane including the infrared optical path and the optical axis of the infrared lens 3 is defined as a plane m, and the infrared optical path is included.
A plane perpendicular to the plane m is defined as a plane s. Also, FIG.
2B, the cross section of the infrared lens 3 cut along the plane m is taken as the cut surface M, and the cross section of the infrared lens 3 taken along the plane s is taken as the cut surface S.

The infrared ray incident on the infrared lens 3 is refracted in its optical path at a point C based on the refractive index of the infrared lens 3. However, as shown in FIG. 5B, since the radius of curvature R of the cut surface M and the radius of curvature r of the cut surface S are different, the refractive indices of infrared rays at the cut surfaces M and S are different, and the astigmatism is different. Aberration occurs. Due to this astigmatism, the image plane of infrared rays becomes a curved solid curved surface as shown in FIG. Even if this astigmatism does not occur, the image plane becomes a curved surface due to the difference in the refractive index.

Due to the above-mentioned astigmatism and the like, the flat light receiving surface of the infrared detecting portion 4 and the curved solid curved image forming surface of the infrared image of the heat source 8 do not actually coincide with each other, and the infrared detecting portion 4
The light receiving surface (sensor element substrate 6) is irradiated with an infrared image of the heat source 8 which is out of focus according to the amount of displacement (distance) between the light receiving surface and the three-dimensional curved image forming surface. That is, the central portion of the light receiving surface and the peripheral portion of the light receiving surface are irradiated with the infrared images of the heat source 8 having different focus shifts. For this reason, it is impossible to install so that a flat infrared receiving surface is uniformly illuminated with an infrared image in focus, and even if an infrared sensor element 5 with high sensitivity is installed, The infrared sensor 1 has a problem that the infrared image of the heat source 8 cannot be detected accurately.

Further, as shown in FIG. 4, the wider the infrared detection area is, the greater the distance between the peripheral edge of the light receiving surface and the three-dimensional curved image forming surface, that is, the amount of focus shift of the infrared image becomes. There is a problem that the detection performance of the sensor 1 deteriorates. Therefore, there is a problem that the infrared detection area of the infrared sensor 1 is limited to be narrow in order not to deteriorate the detection performance of the infrared sensor 1.

Therefore, as a means for widening the infrared detection area of the infrared sensor 1, for example, an infrared sensor 1 for detecting infrared rays by rotating an infrared detection member in which the infrared sensor elements 5 are arranged in a one-dimensional array is rotated. is there. But,
This infrared sensor 1 has a complicated structure due to the large number of movable parts of the module, and the price becomes high.
There is a problem that the movable portion is apt to cause troubles such as not operating smoothly and the reliability is low.

The present invention has been made to solve the above problems, and an object of the present invention is to detect infrared rays imaged on a curved surface due to astigmatism of an infrared lens with high accuracy and to detect infrared rays. An object is to provide an infrared sensor whose detection performance does not deteriorate even if a large area is taken.

[0013]

In order to achieve the above object, the present invention is constructed as follows. That is, the infrared sensor of the first invention is an infrared sensor having an infrared lens that forms an image of infrared rays emitted from a heat source, and a plurality of infrared sensor elements that detect the formed infrared rays. The element is characterized in that it is arranged at a surface position along the three-dimensional curved image forming surface of the infrared lens.

The infrared sensor of the second invention is the first sensor.
Infrared sensor elements constituting the infrared sensor of the invention of claim 1 are formed on a substrate individually or in a plurality of arrayed arrays, and the plurality of substrates on which the infrared sensor elements are formed are three-dimensional curved imaging planes of infrared lenses. A plurality of infrared sensor elements are arranged along the three-dimensionally curved image forming surface of the infrared lens by being combined and arranged along.

[0015]

In the present invention having the above structure, when a heat source such as a fire or a person is present within the detection area of the infrared sensor, the infrared lens takes in the infrared rays emitted from the heat source, and the taken infrared rays are not reflected by the infrared lens. Due to point aberration or the like, an image is formed on the three-dimensional curved image forming surface, that is, the position where the infrared sensor element is arranged. Then, each infrared sensor element detects an output signal corresponding to the amount of infrared irradiation, and the infrared sensor accurately detects the infrared image of the heat source based on the output signal of each infrared sensor element.

[0016]

Embodiments of the present invention will be described with reference to the drawings.
In the description of the present embodiment, the same reference numerals will be given to the same names as those in the conventional example, and detailed description thereof will be omitted.

FIG. 1 shows an infrared sensor 1 of this embodiment. This embodiment is different from the conventional example in that the light receiving surface of the infrared detecting section 4 is not formed on a flat plane, but a plurality of sensor element substrates 6 are formed on the infrared lens 3.
The three-dimensional curved surface formed by astigmatism and the like are combined and arranged to form the three-dimensional light receiving surface of the infrared detection unit 4.

As shown in FIG. 2, the sensor element substrate 6 is formed in a shape that can be incorporated along the three-dimensional curved image forming surface of the infrared lens 3, and the infrared sensor element 5 is formed on the substrate.
Are arranged in a two-dimensional array. Then, the respective sensor element substrates 6 are arranged in combination along the three-dimensional curved image forming plane,
The three-dimensional light receiving surface of the infrared detection unit 4 is formed along the three-dimensional curved image forming surface.

According to this embodiment, since the three-dimensional light receiving surface of the infrared detecting section 4 is formed by combining a plurality of sensor element substrates 6 along the three-dimensional curved image formation of the infrared lens 3, the infrared detecting section is formed. The stereoscopic light receiving surface of 4 and the stereoscopic curved image forming surface of the infrared lens 3 substantially coincide with each other, and the infrared image of the heat source 8 is displayed on the stereoscopic light receiving surface of the infrared detecting section 4 as in the conventional example. The image is clearly projected over the entire surface of the three-dimensional light receiving surface without causing a large focus shift and the infrared sensor 1 can detect the infrared image of the heat source 8 with high accuracy, and the detection performance of the infrared sensor 1 is high. Can be increased.

Further, as described above, since the three-dimensional light receiving surface of the infrared detecting section 4 is formed along the three-dimensional curved image forming surface,
With the flat light receiving surface of the conventional example, the infrared detection region is narrowly limited in order not to deteriorate the detection performance of the infrared sensor 1, but with the three-dimensional light receiving surface of this embodiment, a clear infrared image is formed on the entire surface of the three-dimensional light receiving surface. Therefore, even if the infrared detection area is expanded, the detection performance of the infrared sensor 1 does not deteriorate. From this, it becomes possible to provide the infrared sensor 1 having a wide infrared detection region.

Further, as described above, by forming the three-dimensional light receiving surface of the infrared detecting section 4 as in the present embodiment, it is excellent as described above even without the structure having a large number of movable parts as in the conventional example. In addition, the infrared sensor 1 can have a simple and compact structure because a movable part is not provided, and the infrared sensor 1 having a small size, high performance, and low price can be provided.

Furthermore, as described above, the infrared sensor 1 of the present embodiment does not have a movable portion which is likely to cause troubles, and thus the infrared sensor 1 having high reliability can be provided.

The present invention is not limited to the above-mentioned embodiment, but various modes can be adopted. For example, in the above embodiment, the three-dimensional light receiving surface of the infrared detecting section 4 is formed by using the plurality of sensor element substrates 6 in which the infrared sensor elements 5 are arranged in a two-dimensional array, but one infrared sensor element is used. 5
A plurality of minute sensor element substrates 6 provided with are combined and arranged along the three-dimensional curved image forming surface of the infrared lens 3,
You may form the three-dimensional light-receiving surface of the infrared detection part 4. As described above, the sensor element substrate 6 is made minute (in accordance with the size and shape of the sensor element substrate 6, the infrared sensor elements 5 are arranged on the substrate 6 in a one-dimensional or two-dimensional array, or
If a large number of sensor element substrates 6 (infrared sensor elements 5) are arranged in combination along the three-dimensional curved image forming surface of the infrared lens 3, as shown in FIG. It is possible to form a three-dimensional light receiving surface of the infrared detection unit 4 that matches with.

In addition, a sensor element substrate 6 in the form of a film (including a flexible substrate) and polyvinylidene fluoride (P
If a film-like infrared sensor element 5 formed of VDF) or the like is used and arranged in combination along the three-dimensional curved image forming surface in the same manner as described above, the three-dimensional shape of the infrared detecting section 4 that fits the three-dimensional curved image forming surface very well. A light receiving surface can be formed.

Further, the sensor element substrate 6 itself is molded so as to have a curved surface or a square surface along the three-dimensional curved image forming surface,
The infrared sensor elements 5 may be arranged in an array on the sensor element substrate 6 molded into the curved or square surface to form the three-dimensional light receiving surface of the infrared detecting section 4. By doing so, it is possible to omit a hand gap for arranging a plurality of sensor element substrates 6 as shown in FIG.

[0026]

According to the present invention, the infrared sensor element is
Instead of being placed on a flat plane like the conventional example,
The infrared rays emitted from the heat source are imaged on the three-dimensional curved image forming surface due to the astigmatism of the infrared lens, etc. However, that is because the image is formed at the arrangement position of the infrared sensor element, so the infrared sensor can accurately detect the infrared image of the heat source based on the detection output of the infrared sensor element. The infrared detection performance of can be improved.

Further, as described above, the infrared sensor element is
Since it is arranged along the three-dimensional curved image forming plane of the infrared lens, in the conventional example, in order to show appropriate infrared detection performance,
Although the infrared detection area for detecting infrared rays is narrowly limited, the present invention can exhibit the above-described excellent infrared detection performance without narrowing the infrared detection area. Therefore, it is possible to provide an infrared sensor having a wide infrared detection area.

Further, as described above, by arranging the infrared sensor element at the position of the three-dimensionally curved image forming surface, the above-mentioned excellent effects can be obtained even if the structure is not provided with many movable parts as in the conventional example. The infrared sensor has a simple and compact structure because the infrared sensor is not provided. From the above, it is possible to provide a small-sized, high-performance, low-cost infrared sensor.

Furthermore, as described above, the infrared sensor does not have a moving part which is likely to cause troubles, and thus an infrared sensor having high reliability in the detection operation can be provided.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an infrared sensor of the present embodiment.

FIG. 2 is an explanatory diagram showing an example of a three-dimensional light receiving surface of the infrared detection unit in FIG.

FIG. 3 is an explanatory diagram showing the configuration of another embodiment of the infrared sensor of the present invention.

FIG. 4 is an explanatory diagram showing a conventional example.

FIG. 5 is an explanatory diagram showing astigmatism of infrared rays by an infrared lens.

[Explanation of symbols]

 1 infrared sensor 3 infrared lens 5 infrared sensor element 6 sensor element substrate 8 heat source

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location G01J 5/08 B G01V 8/20

Claims (2)

[Claims] 1. An infrared sensor having an infrared lens for forming an infrared ray emitted from a heat source and a plurality of infrared sensor elements for detecting the formed infrared ray, wherein the plurality of infrared sensor elements are three-dimensional infrared lenses. An infrared sensor, which is arranged at a surface position along a curved image forming surface. 2. The infrared sensor element is a single element on a substrate,
Alternatively, by arranging a plurality of substrates, which are formed by arranging them in an array form and in which the infrared sensor elements are formed, in combination along the three-dimensional curved image forming surface of the infrared lens, the plurality of infrared sensor elements are arranged in the three-dimensional array The infrared sensor according to claim 1, wherein the infrared sensor is arranged along a curved image plane.