JP2001255204A - Pyroelectric infrared sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pyroelectric infrared sensor with satisfactory characteristics by eliminating problems such as variations in sensitivity caused by positional displacement among a sensor element, sensor element support bodies, and a circuit board. SOLUTION: This pyroelectric infrared sensor is equipped with, at least, the sensor element, the support bodies for severally supporting both ends of the sensor element, and the circuit board, with the sensor element fixed to the circuit board by means of the support bodies. The support bodies for severally supporting both ends of the sensor element are formed in one body with each other out of a resin material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a pyroelectric infrared sensor having a small infrared sensor element for detecting infrared rays radiated from an object such as a human body.

[0002]

2. Description of the Related Art In recent years, pyroelectric infrared sensors have been widely used as human body detection sensors and the like.

FIG. 1 is a sectional view showing a conventional pyroelectric infrared sensor. The pyroelectric infrared sensor of FIG. 1 has a structure in which a sensor element 1 is supported on a circuit board 3 by a sensor element support 2. A front surface electrode and a back surface electrode (both not shown) are formed on the front and back surfaces of the sensor element 1 by vapor deposition or sputtering. The sensor element support 2 is made conductive by a conductive material or conductive plating, and the sensor element 1, the sensor element support 2 and the circuit board 3 are electrically connected by a conductive adhesive or the like.

[0004] Reference numeral 4 denotes an infrared filter, which emits infrared light of a certain wavelength that has passed through the infrared filter 4 onto the sensor element 1, thereby generating a charge proportional to the amount of received infrared light due to the pyroelectric effect of the sensor element 1. The voltage generated by the charge is taken out from the lead 6 attached to the base 5 through the circuit board 3. Base 5
The leads 6 are insulated by a hermetic seal or the like. In addition, 7 is a cap.

FIGS. 2A and 2B are views showing a sensor element supporting portion of the pyroelectric infrared sensor of FIG. 1, wherein FIG. 2A is a top view and FIG. 2B is a front view of FIG. The sensor element support 2 is fixed to a predetermined position on the circuit board 3, and the sensor element 1 is mounted on the upper surface of the sensor element support 2. The sensor element 1 has both ends supported by a sensor element support 2, and has a structure in which conduction is established via a conductive adhesive to a back electrode 1 b provided on the sensor element 1. 1a is a surface electrode provided on the sensor element.

[0006]

SUMMARY OF THE INVENTION The sensor element support is
Usually, it is fixed on the circuit board using a conductive adhesive or solder. The positioning of the sensor element support and the circuit board
This is performed using a dedicated positioning jig. Further, the sensor element is fixed to the upper surface of the sensor element support using a conductive adhesive. However, when the sensor element support and the sensor element, which are separate bodies, are fixed respectively, for example, the positional displacement between the circuit board 3 and the sensor element support 2 as shown in FIG. 3, the sensor element support 2 as shown in FIG. And the sensor element 1 are likely to be misaligned. Further, although not shown, a composite displacement between FIGS. 3 and 4 also occurs. Then, the bonding area is likely to vary, and thermal diffusion from the sensor element to the support base causes variation between products. This is a significant problem in characteristics as a variation in sensitivity. In addition, the displacement causes a displacement between the filter window and the surface electrode of the sensor element, which causes a problem in characteristics as a variation in a viewing angle.

[0007] In the manufacturing process, evaluation of the sensor element is performed in-line during mass production. In this case, infrared rays must be projected after the sensor element and the sensor element support are joined to the circuit board. In sensor element evaluation,
Each time a sensor element becomes defective, it must be removed from the circuit board and regenerated, which is a very troublesome operation. In some cases, the entire circuit board must be treated as defective. This results in a large loss of material costs and man-hours, leading to an increase in cost. In view of the above problems, an object is to provide a pyroelectric infrared sensor with good characteristics by eliminating problems such as sensitivity variations caused by displacement of a sensor element, a sensor element support, and a circuit board.

[0008]

According to the present invention, there is provided a pyroelectric infrared sensor comprising at least a sensor element and a sensor element support for supporting both ends of the sensor element, and a circuit board, wherein the sensor element is fixed to the circuit board via the sensor element support. In the sensor,
A pyroelectric infrared sensor in which supports for supporting both ends of the sensor element are integrally formed of a resin material.

[0009] The sensor element support body integrally formed is:
A pyroelectric infrared sensor is provided in which an electrode pattern for establishing conduction between an electrode formed on the sensor element and a circuit board is formed by metal plating.

[0010] The integrally formed sensor element support includes:
The pyroelectric infrared sensor is formed by insert-molding an electrode terminal for conducting between the electrode formed on the sensor element and the circuit board in a resin.

[0011] At least two or more projections are provided on the bottom surface of the integrally formed sensor element support, and the circuit board is provided with an insertion portion corresponding to the projection provided on the bottom surface of the sensor element support. A pyroelectric infrared sensor in which a projection provided on the element support is inserted into an insertion portion provided on the circuit board and positioned and fixed.

[0012]

FIG. 5 is a view showing a sensor element support of a pyroelectric infrared sensor according to a first embodiment of the present invention. (A) is a top view and (b) is a front sectional view.

Reference numeral 8 denotes a sensor element support, and step portions 8a and 8b for positioning and fixing a sensor element (not shown).
have. The sensor element support 8 is formed integrally with a resin material. Reference numeral 9 denotes a pattern which is formed from the steps 8a and 8b of the sensor element support 8 to the side surface of the sensor element support 8,
The voltage generated by the electric charge generated by the pyroelectric effect by being connected to the electrodes of the sensor element fixed to a and 8b is taken out. The pattern 9 is formed by patterning a copper material by plating, for example. Reference numeral 10 denotes a protrusion provided on the bottom surface of the sensor element support 8, which is used for positioning with a circuit board described later.

FIG. 6 is a sectional view of a pyroelectric infrared sensor according to the first embodiment of the present invention. Reference numeral 11 denotes a sensor element which is positioned and fixed to the steps 8a and 8b of the sensor element support 8. The sensor element support 8 is mounted on the circuit board 12, and at this time, the insertion section 12 provided on the circuit board 12 is provided.
By inserting the protruding portion 10 provided on the bottom surface of the support 8 into a, accurate positioning and fixation are achieved. It is sufficient that at least two or more projections 10 are provided, and the insertion portion may be a through hole or a recess.

The sensor element support 8 positioned and fixed on the circuit board 12 has a pattern 9 formed on the surface thereof and a pattern 12b formed on the circuit board 12 formed of the conductive adhesive 1.
Electrical connection is made via 2c, and the pyroelectric infrared sensor is completed.

FIGS. 7A and 7B show a sensor element support of a pyroelectric infrared sensor according to a second embodiment of the present invention. FIG. 7A is a top view and FIG. 7B is a front sectional view.

Reference numeral 13 denotes a sensor element support, which is a step portion 13a for positioning and fixing a sensor element (not shown).
13b. The sensor element support 13 is formed integrally with a resin material. Reference numeral 14 denotes a metal electrode terminal, which is insert-molded when the sensor element support 13 is integrally formed. The electrode terminals 14 are formed from the step portions 13a and 13b serving as the sensor element mounting portions of the sensor element support 13 to the side surface portions of the sensor element support 13, and the electrode terminals 14 of the sensor elements mounted on the step portions 13a and 13b are formed. Connected to an electrode (not shown), the generated voltage is taken out.

The steps 13a, 1a of the sensor element support 13
A sensor element (not shown) is positioned and fixed to 3b.
Further, the sensor element support 13 is provided with a protrusion 15, which is accurately positioned and fixed by inserting the protrusion 15 into an insertion portion provided on the circuit board, similarly to the first embodiment, and the pyroelectric type is provided. The infrared sensor is completed.

[0019]

According to the present invention, the sensor element support is integrally formed, and a step portion for positioning and fixing the sensor element is provided. Therefore, the positioning between the sensor element support and the sensor element is facilitated and the displacement is eliminated. In addition, since a projection is provided on the bottom surface of the sensor element support and inserted into an insertion portion provided on the circuit board and is positioned and fixed, positioning is facilitated, and there is no displacement between the circuit board and the sensor element support. Therefore,
Variations between products due to differences in thermal diffusion caused by a displacement between the sensor element and the sensor element support, and a displacement between the filter window and the sensor element surface electrode are eliminated, and a pyroelectric infrared sensor with good characteristics can be obtained.

Since the sensor element, the sensor element support, and the circuit board are accurately positioned, loss of man-hour can be prevented.

Since the metal plating is patterned on the integrally formed sensor element support, the thickness of the pattern can be reduced, so that the cross-sectional area can be reduced and the heat conduction can be reduced (the heat can hardly escape). In addition, since three-dimensional patterning can be performed by the MID technology, the degree of freedom in design increases.

By forming the sensor element support by insert molding the electrode terminals, an inexpensive sensor element support can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a conventional pyroelectric infrared sensor.

FIGS. 2A and 2B are diagrams showing a sensor element support portion of the pyroelectric infrared sensor of FIG. 1, wherein FIG. 2A is a top view and FIG. 2B is a front view of FIG.

FIG. 3 is a diagram showing a displacement between a circuit board and a sensor element support.

FIG. 4 is a diagram showing a displacement between a sensor support and a sensor element.

5A and 5B are diagrams showing a sensor element support of the pyroelectric infrared sensor according to the first embodiment of the present invention, wherein FIG.
(B) is a front view of (a).

FIG. 6 is a cross-sectional view of a pyroelectric infrared sensor according to the first embodiment of the present invention.

FIGS. 7A and 7B are views showing a sensor element support of a pyroelectric infrared sensor according to a second embodiment of the present invention, wherein FIG.
(B) is a front view of (a).

DESCRIPTION OF REFERENCE NUMERALS 1 sensor element 1a front electrode 1b back electrode 2 sensor element support 3 circuit board 4 infrared filter 5 base 6 lead 7 cap 8 sensor element support 8a step 8b step 9 electrode pattern 10 protrusion 11 sensor Element 12 Circuit board 12a Insertion section 12b Pattern 12c Conductive adhesive 13 Sensor element support 14 Electrode terminal 15 Projection

Claims (4)

[Claims] 1. A pyroelectric infrared sensor comprising a sensor element and a circuit board for supporting at least both ends of the sensor element and the sensor element, wherein the sensor element is fixed to the circuit board via the sensor element support. A pyroelectric infrared sensor, wherein support members for supporting both ends of the sensor element are formed integrally with a resin material. 2. An electrode pattern for establishing electrical connection between an electrode formed on the sensor element and a circuit board is formed on the integrally formed sensor element support body by metal plating. The pyroelectric infrared sensor as described in the above. 3. An electrode terminal for establishing conduction between an electrode formed on the sensor element and a circuit board is insert-molded in a resin on the integrally formed sensor element support. The pyroelectric infrared sensor according to claim 1. 4. At least two or more projections are provided on the bottom surface of the integrally formed sensor element support, and an insertion portion corresponding to the projection provided on the bottom surface of the sensor element support is provided on the circuit board. 4. The pyroelectric infrared sensor according to claim 1, wherein a protrusion provided on the sensor element support is inserted into an insertion portion provided on the circuit board and is positioned and fixed.