JPH0772015A - Infrared sensor - Google Patents

Abstract

(57) [Abstract] [Purpose] An object is to provide an infrared sensor capable of detecting a wide range of angles of 120 ° or more by using a pyroelectric infrared sensor. [Structure] In a pyroelectric infrared array sensor, a plurality of pyroelectric elements 12 are arranged in a matrix, and a substrate 1
It is built into the front of 1. Further, a concave mirror is installed as a reflecting mirror 13 on the front surface of the substrate 11. Pyroelectric element 1
Reference numeral 2 is installed at the focal position of the concave mirror, and infrared rays 14 are reflected by the reflecting mirror 13 and are condensed on the pyroelectric element 12.
By using a concave mirror as the reflecting mirror 13, infrared rays 14 incident from a region of an angle of about 180 ° can be detected, and since there is no rotation mechanism, it can be made compact and can be manufactured at low cost. Further, since the pyroelectric element 12 is installed at the focus position of the concave mirror, infrared detection over a wide range is highly accurate and reliable. In addition, 15 is a chopping means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared sensor for detecting infrared rays.

[0002]

2. Description of the Related Art In recent years, there is an increasing demand for security and air-conditioning control by detecting the presence or absence of a person in a room and the amount of activity of the person. As one method for detecting the presence or absence of human beings in such a room and the amount of human activity, the infrared sensor is used to detect the infrared rays emitted from the human body, and the detected signal is used to determine the presence or absence of human beings. And methods of detecting the amount of human activity have been developed. For example, an infrared sensor is used to detect an infrared source in order to recognize a human body when controlling an environmental control device such as an air conditioner / lighting device or a crime prevention system.

Two types of infrared sensors are known: a quantum sensor that captures infrared rays as photons, and a thermal sensor that utilizes changes in the physical properties of the element that result from a rise in temperature of the element due to absorption of infrared light. However, since the former usually requires cooling with liquid nitrogen or the like, a thermal sensor is generally used. Among thermal sensors, the pyroelectric infrared sensor is more sensitive than others, so it is suitable for infrared source detection.
Pyroelectric infrared sensors basically detect infrared changes, so if you try to detect a stationary infrared source, the infrared will intermittently enter the sensor's light receiving part by some method. It is necessary to devise such a method, and normally, the intermittent incidence (chopping) of infrared rays is realized by rotating or vibrating a chopper such as a disk with a slit or a flat plate.

FIG. 5 is a schematic view of a conventional pyroelectric infrared sensor. A pyroelectric element 42 is incorporated on the substrate 41, and infrared rays 45 are incident on this pyroelectric element 42. The infrared rays 45 intermittently pass through the infrared transmission lens 43 by the chopper 44 and are condensed on the pyroelectric element 42. The mechanism of the chopper 44 allows infrared rays 45
Is intermittently incident on the pyroelectric element 42 to detect polarization change as voltage change.

[0005]

However, with such a mechanism, the infrared rays 45 incident on the pyroelectric element 42 will be described.
Is limited by the viewing angle of the infrared transmitting lens 43, so that the angle range is limited to about 120 °, and there is a problem that it is difficult to observe a wider range.

In view of the above-mentioned problems of the conventional infrared sensor, the present invention uses an infrared sensor such as a pyroelectric infrared sensor to achieve high reliability, low cost, and easy operation.
It is an object to provide an infrared sensor having a wide viewing angle of 0 ° or more.

[0007]

SUMMARY OF THE INVENTION The present invention is an infrared sensor having a plurality of light receiving portions for detecting infrared rays and a light collecting means for collecting the infrared rays on the light receiving portions by a reflecting means for reflecting the infrared rays. .

Further, the present invention is an infrared sensor, wherein the reflecting means is a concave mirror, and a plurality of light receiving portions are installed at the focal position of the concave mirror.

Further, the present invention provides that the above infrared sensor is
A pyroelectric infrared sensor, wherein the reflecting means is a concave mirror composed of a plurality of segment-shaped reflecting mirrors capable of focusing on each of a plurality of light receiving portions. The infrared light incident on is an infrared sensor that is interrupted intermittently by the chopping means.

The present invention is also an infrared sensor, wherein the infrared sensor is a fixed infrared sensor.

Further, the present invention is an infrared sensor, wherein the light condensing means includes, in addition to the reflecting means, a rotating means for simultaneously rotating the light receiving portion and the reflecting means.

[0012]

In the present invention, the plurality of light receiving portions detect infrared rays, and the condensing means condenses the infrared rays on the light receiving portions by the reflecting means for reflecting the infrared rays.

Further, in the present invention, since the reflecting means is a concave mirror and a plurality of light receiving parts are installed at the focal position of the concave mirror, infrared rays can be detected with high accuracy.

Further, according to the present invention, one of the plurality of light receiving parts is provided.
Since a plurality of segment-shaped reflecting mirrors capable of focusing on one focus the infrared light on the light receiving portion, the infrared light can be detected with higher accuracy.

Further, according to the present invention, a wide viewing angle can be secured even if the infrared sensor is a fixed infrared sensor.

Further, according to the present invention, since the rotating means simultaneously rotates the light receiving portion and the reflecting means, it is possible to secure a wider viewing angle.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic view of a pyroelectric infrared sensor according to the first embodiment of the present invention. A concave mirror (reflecting mirror) 13 as an example of a light converging means is installed on the front surface of a substrate 11 in which a plurality of pyroelectric elements 12 as an example of a light receiving section are incorporated in a matrix. These pyroelectric elements 13 form an infrared array sensor. The pyroelectric element 12 is installed at the focal position of the concave mirror 13.
Further, in front of the pyroelectric element 12, chopping means 15 for intermittently changing the infrared rays incident on the pyroelectric element 12 is arranged.

In this structure, when the infrared rays 14 are incident on the reflecting mirror 13, the infrared rays 14 reflected by the reflecting mirror 13 are condensed on the pyroelectric element 12 as shown in the figure.

As described above, by using the concave mirror as the reflecting mirror 13, it is possible to detect the infrared rays 14 incident from a wide range of an angle of about 180 °, and it is possible to make it compact because there is no rotation mechanism. Therefore, it can be manufactured at low cost. The infrared rays 14 in a wide range can be detected with high reliability and high accuracy. Further, since the pyroelectric element 12 is installed at the focal position of the concave mirror, the infrared rays 14 can be detected with higher accuracy.

The concave mirror that can be used at this time is infrared light 14
Any concave mirror may be used as long as it reflects light. Further, when sensing is performed using this concave mirror, the position behind the substrate 11 (or the pyroelectric element 12) cannot be detected. There is no particular problem because it is only a shadow of the area of the small substrate 11 (or the pyroelectric element 12).

As described above, according to this embodiment, by using the fixed type concave mirror reflecting mirror, the chopping means, and the pyroelectric element, infrared rays in a wide range can be obtained with high accuracy, high reliability, low cost. Can be easily detected.

Next, a pyroelectric infrared sensor according to a second embodiment of the present invention will be described with reference to the drawings.

FIG. 2 is a schematic view of a pyroelectric infrared sensor according to the second embodiment of the present invention. Two plane mirrors (reflecting mirrors) 23 are installed on the front surface of a substrate 21 in which a plurality of pyroelectric elements 22 as light receiving portions are incorporated in a matrix.

In such a structure, when the infrared rays 24 are incident on the plane mirror 23, the infrared rays 24 reflected by the two plane mirrors 23 are condensed on the pyroelectric element 22 as shown in the figure.

In this way, by using the plane mirror 23, the infrared rays 2 incident from a wide range of an angle of about 180 °
4 can be detected, and since it has no rotation mechanism, it can be made compact and can be manufactured at low cost. Furthermore, the reliability is high and the infrared rays 24 in a wide range can be detected with high accuracy.

The plane mirror 23 that can be used at this time may be of any type as long as it reflects the infrared rays 24.

As described above, according to this embodiment, the fixed type flat mirror, pyroelectric element, and chopping means (not shown) are used.
By using, high accuracy, high reliability and low cost,
It can easily detect infrared rays in a high range.

Next, a pyroelectric infrared sensor according to a third embodiment of the present invention will be described with reference to the drawings.

FIG. 3 is a schematic view showing a pyroelectric infrared sensor according to the third embodiment of the present invention.

A plurality of pyroelectric elements 32 as light receiving portions are arranged in a matrix. They form a pyroelectric infrared array sensor and are incorporated in the front surface of the substrate 31. Further, on the front surface of the substrate 31, a reflecting mirror 33 which is a concave mirror as a whole is arranged. The reflecting mirror 33 is composed of a segmented concave mirror capable of focusing on each of the matrix-shaped pyroelectric elements 32. The pyroelectric element 32 is installed at each focal position of each segment-shaped concave mirror.

In this structure, when the infrared rays 34 are incident on the reflecting mirror 33, the infrared rays 34 reflected by the reflecting mirror 33 are condensed on the corresponding pyroelectric element 32 as shown in the figure. To do.

As described above, by using the segment-shaped concave mirror capable of focusing on each of the plurality of matrix-shaped pyroelectric elements 32 as the reflecting mirror 33, an angle of about 180 ° can be obtained. Infrared rays 3 coming from a wide range
4 can be detected with higher reliability and higher accuracy. Moreover, since it has no rotation mechanism, it can be made compact and can be manufactured at low cost.

The reflecting mirror 33 that can be used at this time may be of any type as long as it reflects the infrared rays 34.

As described above, according to the present embodiment, a plurality of matrix-shaped pyroelectric elements and a segment-shaped concave mirror capable of focusing on each of the pyroelectric elements are used. This makes it possible to detect infrared rays in a wide range with high accuracy, high reliability and low cost.

Next, a pyroelectric infrared sensor according to a fourth embodiment of the present invention will be described with reference to the drawings.

FIG. 4 is a schematic view showing a pyroelectric infrared sensor according to the fourth embodiment of the present invention.

A plurality of pyroelectric elements 52 as light receiving portions are provided in a matrix. They constitute a pyroelectric infrared array sensor, which is incorporated in the front side of the substrate 51. Further, a reflecting mirror (concave mirror) 53 is installed on the front surface of the substrate 51. The pyroelectric element 52 is installed at the focal position of the concave mirror 53. Furthermore, the substrate 51 and the concave mirror 53 are connected to the motor 5 via the shaft 56.
5 in the same direction as the driven shaft of the shaft 56.
Rotation means is provided which forms a part of the light condensing means for rotating by 0 °.

In this structure, when the infrared ray 54 is incident on the reflecting mirror 53, the infrared ray 54 reflected by the reflecting mirror 53 is condensed on the pyroelectric element 52 as shown in the figure. Thus, by using a concave mirror as the reflecting mirror 53,
It is possible to detect the infrared rays 54 incident from a wide range of an angle of about 80 °. Further, it is possible to drive the shaft 5 by the motor 55 to rotate the substrate 51 and the concave mirror 53, and to detect the infrared rays 54 over a wider range than 180 ° and more than 360 °.

As described above, according to this embodiment, the rotary concave mirror and the chopping means (not shown) are used.
By using, it is possible to easily detect a wide range of infrared rays with high accuracy and high reliability.

The light converging means of the present invention includes the above-mentioned first to third embodiments.
In the third embodiment, only the reflecting means such as the concave mirror or the segmented reflecting mirror is used, and in the fourth embodiment, the rotating means is also used. However, various condensing mechanisms other than these may also be used together. good.

Further, the light receiving portion of the present invention is a pyroelectric element in the above embodiment, but may be an infrared sensor element other than that.

Further, although the reflecting means of the present invention is a mirror in the above-mentioned embodiment, in short, any number of convex mirrors, plane mirrors, concave mirrors, etc. can be used as long as they can reflect light and collect the light to the light receiving portion. Can be used.

[0044]

As is apparent from the above description, the present invention comprises a plurality of light receiving portions for detecting infrared rays, and a light collecting means for collecting the infrared rays on the light receiving portions by the reflecting means for reflecting the infrared rays. By preparing. It is possible to provide an infrared sensor having a simplified structure, a low cost, and a wide viewing angle.

In particular, by attaching the reflecting means to the front surfaces of the plurality of light receiving portions, it is possible to detect infrared rays in a wide range with high accuracy and high reliability.

Further, by using a concave mirror as the reflecting means, it is possible to detect infrared rays incident from a wide range of a viewing angle of about 180 °. Further, by installing the plurality of light receiving portions at the focal position of the concave mirror, infrared rays can be detected with high accuracy.

Further, if a segment-shaped reflecting mirror capable of focusing on each of a plurality of light-receiving portions in a matrix is used as the reflecting means, infrared rays can be detected with higher accuracy.

Further, the mechanism using the reflecting means has a wider viewing angle than that of the conventional one, so that the infrared sensor can be of a fixed type and structurally simple, so that the cost is low. Achieve high precision and high reliability.

Further, the condensing means of the present invention is provided with a rotating means for simultaneously rotating the plurality of light receiving portions and the reflecting means in addition to the reflecting means, so that the condensing means can be used in an even wider range such as 360 °. It is possible to sequentially detect the infrared rays of.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a pyroelectric infrared sensor according to a first embodiment of the present invention.

FIG. 2 is a schematic sectional view of a pyroelectric infrared sensor according to a second embodiment of the present invention.

FIG. 3 is a schematic sectional view of a pyroelectric infrared sensor according to a third embodiment of the present invention.

FIG. 4 is a schematic sectional view of a pyroelectric infrared sensor according to a fourth embodiment of the present invention.

FIG. 5 is a schematic sectional view of a conventional pyroelectric infrared sensor.

[Explanation of symbols]

 11,21,31,51 Substrate 12,22,32,52 Pyroelectric element 13,23,33,53 Reflector 14,24,34,54 Infrared 15 Chopping means

Claims (5)

[Claims] 1. An infrared sensor comprising: a plurality of light receiving parts for detecting infrared rays; and a light collecting means for collecting the infrared rays on the light receiving parts by a reflecting means for reflecting the infrared rays. 2. The infrared sensor according to claim 1, wherein the reflecting means is a concave mirror, and the plurality of light receiving parts are installed at a focal position of the concave mirror. 3. The infrared sensor is a pyroelectric infrared sensor, and the reflecting means is composed of a plurality of segmented reflecting mirrors capable of focusing on each of the plurality of light receiving portions. 3. The infrared sensor according to claim 1, wherein the infrared mirror is a concave mirror, and infrared rays incident on the pyroelectric infrared sensor are interrupted intermittently by chopping means. 4. The infrared sensor according to claim 1, wherein the infrared sensor is a fixed infrared sensor. 5. The infrared sensor according to claim 1, wherein the light condensing unit is provided with a rotating unit that simultaneously rotates the light receiving unit and the reflecting unit, in addition to the reflecting unit.