JPH08313339A - Inrfared ray detector - Google Patents

Abstract

PURPOSE: To hold positional relationship (an optical axis) between a condensing part and an infrared ray sensor always constant by installing the condensing part integrally formed with a support part in front of an incident window of the infrared ray sensor through the support part. CONSTITUTION: A condensing part 8 composed of a Fresnel lens or the like formed of polyethylene resin or the like being an infrared ray transmissive material, is arranged on a top surface 9A of a support part 9. When the condensing part 8 and the support part 9 are formed of the same material, both are integrally formed by an injection mold or the like. When a can case 11 of an infrared ray sensor is fitted to a space part of the support part 9, since the condensing part 8 and an opening part 15 arranged in a top surface 11 of the case 11 are correctly opposed to each other, a peripheral part of a metallic header 10 of the case 11 and a flange 17 on the lower end of a side surface 9B of the support part 9 are fixed together in this state. Therefore, since positional relationship between the condensing part 8 and an infrared ray sensing element part 12, that is, an optical axis of both is kept always constant, an adjustment of the optical axis becomes unnecessary, the number of parts is reduced, and this can be easily assembled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared detector for detecting infrared rays emitted from a heat source to be detected such as a human body and detecting information on the distribution, position, movement, etc. of the detection object.

[0002]

2. Description of the Related Art A pyroelectric infrared sensor or a bolometer is generally used as a sensor for detecting infrared rays emitted from a heating element. The pyroelectric infrared sensor uses a pyroelectric material having a pyroelectric effect such as lead titanate (PbTiO3) as an infrared sensing element. What is the pyroelectric effect?
When infrared rays are incident and a temperature change occurs on the surface of the infrared sensing element, the neutralized state of the electric charge, which was stable until now, is destroyed, and an electrical imbalance occurs, and the electric charge is generated. This generated charge is taken out as a voltage by impedance conversion. The bolometer is a resistance temperature sensor using a metal or semiconductor having a large resistance temperature coefficient as an infrared sensing element, and has a thin film or thick film structure to reduce the heat capacity and enhance the detection sensitivity. .

Various detection devices using such a sensor for detecting infrared rays have been proposed. However, particularly when used for crime prevention sensors and home electric appliances, the visual field range for detection is as wide as possible and the resolution is high to some extent. Is desired to be obtained. Therefore, an array sensor in which a plurality of infrared sensing elements are arranged one-dimensionally or two-dimensionally is used. Further, in order to focus the infrared rays emitted from the heating element on each infrared sensing element, it is common to use a condensing means such as a Fresnel lens, a spherical lens, or an aspherical lens in combination with the array sensor. Target.
The Fresnel lens is a plate made of plastic or the like in which a plurality of lenses each having a stepwise cross section are engraved so as to have a thick lens optical property, that is, a wide viewing angle.

FIG. 7 shows a schematic view of a thermal image detecting device disclosed in Japanese Patent Laid-Open No. 6-94532 as an example in which an array sensor and a lens are combined.

The thermal image detecting device comprises an infrared sensor 1, an infrared transmitting lens 2, a lens holder 3, a support portion 4,
It is composed of parts such as a chopper mechanism 5. The infrared sensor 1 has a pyroelectric type thin film heat detection element group 6 arranged one-dimensionally. An infrared transmitting lens 2 for focusing infrared rays radiated from a heat source within a visual field range to be detected on the pyroelectric thin film heat detecting element group 6 is provided on a front surface of an infrared incident window (not shown) of the infrared sensor 1. Will be placed. The infrared transmitting lens 2 is held by the lens holder 3, and the lens holder 3 is supported by the supporting portion 4. Further, on the front surface of the infrared transmitting lens 2, a chopper mechanism 5 for interrupting infrared rays incident on the infrared sensor 1 is provided.

[0006]

However, when the optical system portion of the thermal image detecting device is assembled using the infrared transmitting lens 2, the lens holder 3, and the supporting portion 4, the dimensional error of each of these plurality of parts is obtained. As a result, the positional relationship between the infrared transmissive lens 2 and the pyroelectric thin film heat detection element group 6, that is, the deviation of the optical axis of the infrared transmissive lens 2 becomes large. Therefore, it has been necessary to adjust the deviation of the optical axis for each thermal image detection device. Further, even if the adjustment is made, the deviation of the optical axis cannot be completely eliminated, so that there is a problem that the detection characteristics between the thermal image detection devices are not constant. Further, it takes time to adjust the optical axis and assemble a plurality of parts, which causes a problem of high manufacturing cost. Furthermore, since a plurality of parts are used, parts management is complicated.

Therefore, the present invention has an object to provide an infrared detector for solving the above problems.

[0008]

In order to achieve the above object, the present invention is configured as follows. That is, first,
In an infrared detector using an infrared sensor in which a plurality of infrared sensing elements are arranged in an array, a condensing section for condensing infrared rays on the infrared sensing element, and a support section formed integrally with the condensing section. And, wherein the condensing unit is attached to the infrared sensor via the supporting unit, secondly,
In the first invention, the light collecting portion and the support portion are formed of the same material. Thirdly, in the first invention,
A locking part for locking the infrared sensor and the support part is formed integrally with the support part by using the same material as the support part. Fourthly, in the first invention, The supporting portion is formed of a material having a thermal conductivity smaller than that of the case of the infrared sensor, and the infrared sensor is covered by the light collecting portion and the supporting portion. Fifthly, in the first invention, A Fresnel lens is used as the light collecting unit. Sixthly, in the second invention, the light collecting unit and the supporting unit are formed using polyethylene resin.

[0009]

Since the light collecting part and the supporting part are integrally formed, the light collecting part can be attached to the front surface of the infrared incident window of the infrared sensor through the supporting part. Therefore, the positional relationship between the condensing unit and the infrared sensor is maintained in a constant state.

By providing the engaging portion integrally with the supporting portion, the supporting portion is engaged with the infrared sensor. Therefore, the supporting portion is securely fixed to the infrared sensor, and the positional displacement does not occur.

When the supporting portion, or the light condensing portion and the supporting portion are formed by covering the infrared sensor with a material having a thermal conductivity smaller than that of the infrared sensor, the ambient temperature can be the case of the infrared sensor. It becomes difficult to communicate. Therefore, even when used in an environment where the ambient temperature fluctuates, it is less likely to be affected by the temperature change.

When the light collecting portion is integrally formed with the supporting portion and the fixing portion by using polyethylene resin, it is less expensive than the case where silicon, germanium or the like is used.
Further, it can be easily formed by using means such as injection molding.

When a Fresnel lens is used as the light collecting part, the thickness of the light collecting part becomes thin.

[0014]

【Example】

(Embodiment 1) A first embodiment of the present invention will be described with reference to FIGS.

The infrared detector comprises an infrared sensor 7, a condenser 8 and a support 9.

The infrared sensor 7 includes a metal header 10 and
It is composed of a can 11 and an element portion 12. The metal header 10 is, for example, in the shape of a rectangular plate, and has terminal pins 13 that are planted on the periphery via insulating cylinder pieces (not shown).
And the ground terminal pin 14 attached to the metal header
Is provided. The element portion 12 is supported and fixed on the upper surface of the metal header 10 via a substrate (not shown) connected to the terminal pins 13 and the ground terminal pins 14. In the element unit 12, a plurality of infrared sensing elements for detecting infrared rays radiated from a heat source within a visual field range to be detected are arranged in an array. The outputs of the plurality of infrared sensing elements are taken out via the terminal pin 13 and the ground terminal pin 14. An infrared filter 16 functioning as an infrared incident window is adhesively fixed to the opening 15 provided on the top surface 11A of the can case 11. In addition, in general
The thickness of the sleeve 11 is, for example, 0.2 mm because it is easy to process.
It is formed by pressing a thin iron-based metal plate material, and a flange 17 is formed at the lower end of the side surface 11B of the can case 11. The flange 17 may not be provided. After covering the metal header 10 with the casing 11, the flange 17 and the peripheral portion of the metal header 10 are fixed by means of, for example, resistance welding.

A Fresnel lens, a spherical lens, an aspherical lens, or the like is used for the condensing unit 8. The light condensing unit 8 is formed by using a substrate such as polyethylene resin, which is a material that transmits infrared rays, or silicon or germanium. When polyethylene resin is used, it is molded by means such as mold molding. When a substrate made of silicon, germanium, or the like is used, it is molded by means such as etching or polishing.

The supporting portion 9 is composed of a top surface 9A and a side surface 9B. The light collecting unit 8 is disposed on the top surface 9A. The top surface 9A is a rectangular plate, and a side surface 9B is formed so as to extend vertically from the peripheral edge of the top surface 9A in a connected state.
The case 11 of the infrared sensor 7 is fitted in the space of the support 9 formed by the top surface 9A and the side surface 9B. In order to prevent rattling when the case 11 is fitted in this space, the dimension of the space parallel to the top surface 9A is the dimension parallel to the top 11A of the case 11. The dimension of the space portion in the direction perpendicular to the top surface 9A is the same as or slightly shorter than the dimension perpendicular to the top surface 11A of the case 11. The light collector 8 is
It faces the opening 15 of the case 11. Support part 9
Is formed of vinyl chloride resin, polyethylene resin, or the like. When the condensing part 8 and the supporting part 9 are made of the same material that transmits infrared rays, the both are integrally molded by means of injection molding or the like. In the case of molding with different materials, the light collecting portion 8 is first molded and then integrally molded by means of insert molding or the like.

When the support case 9 is placed on the can case 11 and the can case 11 is fitted in the inner space of the support part 9, the top surface 11A of the can case 11 and the top surface 9 of the support part 9 are fitted.
The support portion 9 is securely fixed to the infrared sensor 7 in the state where A is in contact. As a result, the positional relationship between the condenser 8 and the infrared sensor 7 is maintained in a constant state.

The thermal conductivity of the resin material is extremely smaller than that of the metal material. For example, the thermal conductivity of polyethylene resin is about 0.25 to 0.34 (W · m-1 · K-1), whereas the thermal conductivity of iron is 83.5 (W · m-1 · K-1). ) Is about. Therefore, when the support portion 9 or the light converging portion 8 and the support portion 9 are formed by using, for example, polyethylene resin, it is difficult for the ambient temperature change to be transmitted to the can case 11 through the support portion 9. Therefore, even when the infrared detector is used in an environment where the ambient temperature fluctuates, malfunctions due to changes in the ambient temperature are reduced, and infrared rays radiated from a heat source within the visual field range to be detected can be reliably detected. .

(Second Embodiment) A second embodiment of the present invention will be described with reference to FIGS. 3 and 4. Since the parts other than the locking part 18 are the same as those in the first embodiment, the description thereof will be omitted and the same numbers will be used.

The engaging portion 18 is integrally provided by projecting at the center of the lower ends of the short side surfaces on both sides forming the side surface 9B. The locking portion 18 is composed of three rectangular plates 18A, 18B and 18C. The rectangular plates 18A and 18C are arranged so as to face each other, and the rectangular plates 18B are connected to the opposite ends of the rectangular plates 18A and 18C. The cross-sectional shape of the locking portion 18 formed in this way is a U-shape. The dimension between the side surface 9B and the rectangular plate 18B is made slightly longer than the width of the flange 17 of the casing 11. The dimension between the rectangular plate 18A and the rectangular plate 18C is the same as the thickness of the welded portion of the case 11 and the metal header-10. Rectangular plate 18
A is vertically installed at the center of the lower end of the short side surface of the side surface 9B so that the surface of the rectangular plate 18A and the top surface 9A are parallel to each other. The locking portion 18 is formed integrally with the support portion 9 at the same time.
Further, the locking portion 18 can be spread in the long side direction of the top surface 9A by the elasticity of the rectangular plate 18A.

After covering the support case 9 on the can case 11,
The locking portion 18A is expanded to lock the rectangular plate 18C on the bottom surface of the metal header-10. As a result, the support portion 9 is securely fixed to the infrared sensor 7 via the locking portion 18 and is not detached. The locking portion 18 is the side surface 9A of the support portion 9.
May be connected to the central portion of the lower end of the long side, or a plurality of pairs may be provided.

(Third Embodiment) A third embodiment of the present invention will be described with reference to FIGS. 5 and 6. Other than the locking portion 19 and the flange of the can case 11, the same as in the first embodiment,
The description is omitted and the same numbers are used.

The engaging portion 19 is integrally provided so as to project from the lower center of the short side surfaces on both sides constituting the side surface 9B. No flange 17 is provided on the case 11. Therefore, after covering the metal header 10 with the case 11 and using a means such as electric welding, the case 1
The lower part of 1 and the peripheral part of the metal header-10 are fixed. The locking portion 19 is a combination of two rectangular plates 19A and 19B in an L shape, and the rectangular plates 19A and 19B have the same plate thickness as the side surface 9B. The size between the lower portion of the side surface 9A of the support portion 9 and the rectangular plate 19B is the metal header-1.
The thickness is almost the same as 0. The rectangular plate 19A is vertically installed at the lower center of the short side surface of the side surface 9B such that the surfaces of the rectangular plate 19A and the side surface 9B are flush with each other. The locking portion 19 is integrally formed with the support portion 9 at the same time. The locking portion 19 can be spread in the long side direction of the top surface 9A of the support portion 9 by the elasticity of the rectangular plate 19A.

After covering the support case 9 on the can case 11,
The locking portion 19A is expanded to lock the rectangular plate 19B on the bottom surface of the metal header-10. As a result, the support portion 9 is securely fixed to the infrared sensor 7 via the locking portion 19,
It does not come off. The locking portion 19 may be connected to the central portion of the lower end surface of the long side of the side surface 9A of the support portion 9, or a plurality of pairs may be provided.

[0027]

Since the present invention is constructed as described above, it has the following effects. That is, first, since the light collecting section is formed integrally with the supporting section, the positional relationship between the infrared sensor and the light collecting section, that is, the optical axis of the light collecting section is always kept constant, and the optical axis can be adjusted. It becomes unnecessary. As a result, the process for adjusting the optical axis becomes unnecessary, and the number of parts is reduced, so that the assembly is simplified. As a result, it can be manufactured at low cost. Secondly, when the support portion and the infrared sensor are fixed by the locking portion, both are securely fixed and no positional deviation occurs. Therefore, for example, even when the infrared detector is used in an environment where vibration is applied, the optical axis of the condensing unit is always kept constant and the imaging performance is not deteriorated. Therefore, the reliability of the infrared detector is maintained for a long time.
Thirdly, when the supporting part, or the condensing part and the supporting part are formed of a material whose thermal conductivity is smaller than that of the case of the infrared sensor, even if the infrared detector is used in an environment where the ambient temperature fluctuates. Since it is less susceptible to temperature changes, malfunctions and the like are reduced, and the reliability of the infrared detector is improved. Fourthly, when the light collecting section is made of polyethylene resin integrally with the supporting section and the fixing section, the light collecting section can be manufactured inexpensively and easily. Fifth, when a Fresnel lens is used as the light collecting unit, the thickness of the light collecting unit becomes thin and the attenuation of infrared rays at the light collecting unit is reduced. As a result, the efficiency of condensing infrared rays is improved, and thus the sensitivity of the infrared detector is improved.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a first infrared detector according to the present invention.

FIG. 2 is a cross-sectional view taken along the line AA ′ of the first infrared detector shown in FIG.

FIG. 3 is an exploded perspective view of a second infrared detector according to the present invention.

FIG. 4 is a cross-sectional view taken along the line AA ′ of the second infrared detector shown in FIG.

FIG. 5 is an exploded perspective view of a third infrared detector according to the present invention.

6 is a cross-sectional view taken along the line AA ′ of the third infrared detector shown in FIG.

FIG. 7 is a diagram showing an outline of a conventional thermal image detecting device.

[Explanation of symbols]

 1 Infrared Sensor 2 Infrared Transmission Lens 3 Lens Holder 4 Supporting Part 7 Infrared Sensor 8 Condensing Part 9 Supporting Part 10 Metal Header-11 Can Case 12 Element Part 13 Terminal Pin 14 Ground Terminal Pin 15 Opening 16 Infrared Filter- 17 Flange 18, 19 Locking part

Claims (6)

[Claims] 1. An infrared detector using an infrared sensor in which a plurality of infrared sensing elements are arranged in an array, and a condensing section for condensing infrared rays on the infrared sensing element, and the condensing section are integrally formed. Infrared detector, characterized in that the condensing unit is attached to the infrared sensor via the supporting unit. 2. The infrared detector according to claim 1, wherein the light collecting portion and the supporting portion are formed of the same material. 3. The infrared detector according to claim 1, wherein the locking portion for locking the infrared sensor and the support portion is formed integrally with the support portion by using the same material as the support portion. . 4. The light collecting section and the supporting section are formed of a material having a thermal conductivity smaller than that of the case of the infrared sensor, and the infrared sensor is covered by the light collecting section and the supporting section. The infrared detector according to claim 1. 5. The infrared detector according to claim 1, wherein a Fresnel lens is used as the light condensing unit. 6. The infrared detector according to claim 2, wherein the light collecting portion and the supporting portion are formed of polyethylene resin.