JP2010054250A - Infrared detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent contact of a circuit block with sealing compound while the clearance in a cap is sealed airtightly by the sealing compound, and to prevent reduction of the detection sensitivity of infrared rays and breakage of a circuit block. <P>SOLUTION: This infrared detector comprises an infrared detecting element 1, a circuit block 2 having a signal processing circuit, a stem 3, a cap 4, and a cover 5. The stem 3 is formed in a plate shape, and the circuit block 2 is mounted on one surface thereof. The cap 4 is formed in a closed-end cylindrical shape whose one end is opened, stores the circuit block 2 inside, and is stuck to the stem 3. An opening window section 4b is disposed on a bottom section 4a facing the infrared detecting element 1 of the cap 4. The cover 5 is made of light-transmitting material, and is arranged from the inside of the cap 4 so as to cover the window section 4b. The cap 4 has a stepped section 4d projected in the inside direction over the whole circumference in a side wall section 4c near the bottom section 4a, and the clearance between the cover 5 and the window section 4b is filled with the sealing compound. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an infrared detector used for human body detection and the like.

Conventionally, various infrared detectors that detect a human body by reading the amount of change in infrared rays have been provided (see, for example, Patent Documents 1 and 2). Such infrared detectors are widely used in crime prevention devices that detect the entry of suspicious persons and control devices that perform load control such as lighting as energy saving measures.

An example of the infrared detector is shown in FIG. This infrared detector includes an infrared detection element 51 and a circuit block 52 provided with a signal processing circuit for processing a signal output from the infrared detection element 51, a stem 53, a cap 54, and a cover 55. The stem 53 is formed in a substantially disc shape, and the circuit block 52 is placed on one surface side. The cap 54 is formed in a bottomed cylindrical shape with one end opened, and the circuit block 52 is formed inside the cap 54.
And is attached to the stem 53. In addition, a window portion 54b that is opened in a rectangular shape is provided at the center portion of the bottom portion 54a that faces the infrared detection element 51 of the cap 54. The cover 55 is formed of a translucent material as a whole in substantially the same shape as the window portion 54b, and the lens portion 5
5a and a flange portion 55b, and closes the window portion 54b from the inside of the cap 54. The lens portion 55a refracts infrared light from the outside to receive the light receiving surface of the infrared detecting element 51 (upper surface in FIG. 9).
Condensed to The flange portion 55b extends outward from the periphery of the lens portion 55a and is fixed to the periphery of the window portion 54b.

By the way, an operation procedure for fixing the cover 55 to the window portion 54b of the cap 54 will be briefly described with reference to FIG. First, as shown to Fig.10 (a), a conductive adhesive is apply | coated to the adhesion part 56 of the periphery of the window part 54b. Next, as shown in FIG.
A is fitted into the window portion 54b from the inside of the cap 54, and the flange portion 55b is bonded to the bonding portion 56 via a conductive adhesive. However, the cover 55 and the window portion 5 are only bonded by the conductive adhesive.
The gap with 4b cannot be completely sealed. Therefore, as shown in FIG. 10C, after the conductive adhesive is sufficiently cured, the gap is sealed by pouring the sealant into the periphery of the flange portion 55b. The sealing portion 57 is a member in a state where the sealing agent is solidified.
JP 2008-20420 A JP 2008-128912 A

However, in the case of a conventional infrared detector, the sealant that contacts the side wall 54c in the vicinity of the bottom 54a is exposed to the opening side of the cap 54 along the side wall 54c by the surface tension as shown in FIG. Direction). Then, if the sealing agent is solidified as the sealing portion 57 in this scooping state, the end portion of the circuit block 52 contacts the scooping portion in the cap 54 when the cap 54 is attached to the stem 53. To do. This contact
There is a difference between the center of the light receiving surface of the infrared detecting element 51 and the optical axis of the lens portion 55a, or there is a difference in the distance between the light receiving surface and the lens portion 55a with respect to the optical axis direction. Therefore, there has been a problem that the detection sensitivity of infrared rays is lowered. Further, there is a problem that the circuit block 52 is damaged by this contact.

The present invention has been made in view of the above reasons, and its purpose is to prevent contact between the circuit block and the sealant while airtightly sealing the gap in the cap with the sealant, and to detect infrared rays. An object of the present invention is to provide an infrared detector capable of preventing a reduction in sensitivity and a circuit block from being damaged.

In order to achieve the above-mentioned object, the invention according to claim 1 is formed in a plate shape and a circuit block provided with an infrared detection element and a signal processing circuit for processing a signal output from the infrared detection element. A stem on which the circuit block is placed on one surface side, a cap formed in a bottomed cylindrical shape with one end opened, the circuit block being housed therein and attached to the stem, and the infrared detection of the cap A translucent cover that closes a window that opens at the bottom facing the element, the cover condensing infrared rays on the light receiving surface of the infrared detection element, and from the periphery of the lens part to the outside A cap that extends and is fixed to the periphery of the window, and the cap includes a stepped portion projecting inward over the entire circumference on the side wall near the bottom. The gap between the cover and the window is Characterized in that it is sealed by a sealant.

According to this invention, since the cap includes a stepped portion projecting inwardly over the entire circumference on the side wall portion near the bottom portion, from the stepped portion to the opening side of the cap, The sealant does not scoop up due to surface tension. Therefore, the gap between the cover and the window in the cap is hermetically sealed with a sealant, while preventing contact between the circuit block and the sealant, and the light receiving surface of the infrared detection element It is possible to prevent a decrease in infrared detection sensitivity due to a positional shift and damage to the circuit block.

According to a second aspect of the present invention, in the first aspect of the invention, the circuit block is in contact with the stepped portion in the optical axis direction of the lens portion.

According to this invention, since the circuit block contacts the stepped portion in the optical axis direction of the lens portion, the distance between the light receiving surface of the infrared detecting element and the lens portion can be kept constant. it can. Therefore, the circuit block can be stably disposed at a place where the infrared rays from the lens unit are efficiently condensed on the light receiving surface.

According to a third aspect of the present invention, in the first or second aspect of the invention, the circuit block is held in a direction perpendicular to the optical axis of the lens portion by the side wall portion on the opening side from the stepped portion of the cap. It is characterized by that.

According to this invention, the circuit block is held in the direction perpendicular to the optical axis of the lens portion by the side wall portion on the opening side of the step portion of the cap. The circuit block can be maintained at a position where the optical axis of the lens unit intersects, and infrared rays can be efficiently condensed on the light receiving surface.

In the present invention, while the gap in the cap is hermetically sealed with a sealant, the contact between the circuit block and the sealant can be prevented, the infrared detection sensitivity can be reduced, and the circuit block can be prevented from being damaged. effective.

(Embodiment 1)
Hereinafter, Embodiment 1 of the present invention will be described with reference to FIGS.

As shown in FIGS. 1 and 2, the infrared detector according to the first embodiment includes an infrared detection element 1 including a pyroelectric element, a circuit block 2 provided with a signal processing circuit, a stem 3, a cap 4, And a cover 5.

As shown in FIG. 2, the circuit block 2 has a first printed wiring board 6, a resin layer 7, a shield plate 8, and a second printed wiring board 9, which are formed in the substantially same octagonal plate shape. It is formed by doing. On one surface side of the first printed wiring board 6, an IC 10 that is a component of the signal processing circuit described above is flip-chip mounted, and on the other surface side, a plurality of chip-shaped electronic components 11 are mounted.
Is mounted by solder reflow (the IC10 mounting surface in FIG. 2 is the lower surface). The IC 10 is integrated with an amplifier circuit that amplifies the output of the infrared detection element 1. The resin layer 7
It is formed of a synthetic resin material. The shield plate 8 is formed by coating the surface of an insulating substrate such as glass epoxy with a metal layer formed of a metal material (for example, copper). The shield plate 8 is for preventing an oscillation phenomenon due to capacitive coupling between the infrared detection element 1 and the amplifier circuit. When the amplification degree of the amplifier circuit is relatively small and the oscillation phenomenon hardly occurs, The shield plate 8 may be omitted. The infrared detection element 1 is mounted on the second printed wiring board 9, and a thermal insulation hole 9 a for thermally insulating the infrared detection element 1 and the second printed wiring board 9 is provided in the thickness direction. Has been. The heat insulating hole 9a forms an air layer between the infrared detecting element 1 and the shield plate 8, and the sensitivity of the infrared detecting element 1 is increased. And these 1st printed wiring boards 6, resin layer 7, shield board 8, and 2nd printed wiring board 9
The through holes 6b, 7b, 8b, and 9b are respectively provided in the thickness direction.

The stem 3 is formed in a substantially disc shape by a steel material, and a flange portion 3a extending outward is provided on the periphery thereof. Three stems 3 (for power supply, signal output, and ground)
The terminal pin 3b is provided penetrating in the thickness direction. The three terminal pins 3b are sequentially inserted into the through holes 6b, 7b, 8b, 9b of the circuit block 2 and fixed with an adhesive so that the circuit block 2 is attached to one surface side of the stem 3 (FIG. 1). And on the upper surface side in FIG. And the infrared detection element 1 and the signal processing circuit of the 1st printed wiring board 6 are electrically connected through the terminal pin 3b. Note that a spacer 12 formed in an approximately square shape with an insulating material is interposed between the stem 3 and the circuit block 2.

The cap 4 is formed in a bottomed cylindrical shape whose one end is opened by a steel material (the lower surface in FIGS. 1 and 2), and an outer flange portion 4e is extended outward from the periphery of the opening. The cap 4 is attached to the stem 3 by housing the circuit block 2 placed on the stem 3 and welding the outer flange portion 4 e to the flange portion 3 a of the stem 3. In addition, a window portion 4b having a rectangular shape (in the present embodiment, a square shape) is provided at the center portion of the bottom portion 4a of the cap 4 facing the infrared detection element 1. And the cap 4 of this Embodiment 1
As shown in FIGS. 1 and 3, the side wall 4c in the vicinity of the bottom 4a is provided with a step 4d projecting inward along the entire circumference.

The cover 5 is formed of a translucent material as a whole in substantially the same shape as the window portion 4b, has a lens portion 5a and a flange portion 5b, and is disposed from the inside of the cap 4 so as to cover the window portion 4b. Yes.
The lens unit 5a is a semiconductor lens made of a silicon lens, and refracts infrared light from the outside to collect it on the light receiving surface (upper surface in FIG. 1) of the infrared detecting element 1. The flange portion 5b extends outward from the periphery of the lens portion 5a, and is fixed to the adhesive portion 13 to which the conductive adhesive on the periphery of the window portion 4b is applied. Since the cover 5 and the cap 4 are electrically connected via the adhesive portion 13, the electromagnetic shielding effect against external noise can be enhanced and the infrared detecting element 1 can be protected from electromagnetic noise.

  The gist of the infrared detector according to the first embodiment will be described.

As described in the prior art, the gap between the cover 5 and the window 4b cannot be completely sealed only by fixing with the conductive adhesive, and it is necessary to pour the sealant. In the conventional infrared detector, the sealant causes the surface tension to crawl up toward the opening side of the cap 4 along the side wall portion 4c, and the circuit block 2 and the sealing portion 14 solidified in the crawl-up state contact each other. There was a case.

However, the side wall 4c in the vicinity of the bottom 4a of Embodiment 1 is provided with a step 4d.
As shown in FIG. 3, the sealing agent may be poured into a recess formed by the bottom 4 a, the step 4 d, and the flange 5 b of the cover 5. That is, if the sealant is poured so as not to overflow from the step 4d to the opening side of the cap 4, the sealant crawls up to the side wall 4c on the cap 4 opening side by the surface tension from the step 4d. There is nothing. Therefore, the gap between the cover 5 and the window 4b in the cap 4 is hermetically sealed with a sealant, while preventing contact between the circuit block 2 and the sealant, reducing the infrared detection sensitivity, and Damage to the circuit block 2 can be prevented. The sealing part 14 is a member in a state where the sealing agent is solidified.

(Embodiment 2)
Hereinafter, Embodiment 2 of the present invention will be described with reference to FIGS. Since the basic configuration of the second embodiment is the same as that of the first embodiment, the same components are denoted by the same reference numerals and description thereof is omitted.

In the second embodiment, as shown in FIG. 4, the circuit block 2 is connected to the lens unit 5 with respect to the stepped portion 4d.
It is characterized in that it abuts in the optical axis direction a (vertical direction in the figure). By this contact, the distance from the lens portion 5a to the light receiving surface of the infrared detecting element 1 in the optical axis direction can be kept constant. That is, the circuit block 2 can be stably disposed at a position where the focal length of the lens portion 5a matches the distance from the lens portion 5a to the light receiving surface. Therefore, the infrared rays from the lens unit 5a can be efficiently collected on the light receiving surface.

By the way, in the above description, the circuit block 2 is in contact with the step portion 4d shown in the first embodiment. However, as shown in FIG. 5, if another step portion 4f is formed in the same manner in addition to the step portion 4d and brought into contact with the step portion 4f, the effect of preventing contact between the circuit block 2 and the sealant is achieved. Can be increased. Moreover, all the above-mentioned step part 4d (or 4f) protruded inward in the shape of a right-angled step. However, as shown in FIG. 6, the side wall portion c in the vicinity of the bottom portion 4a is bent inward over the entire circumference and further contracted in the optical axis direction of the lens portion 5a, whereby the step portion 4d (or 4f) is formed. If formed and brought into contact with the step 4d (or 4f), the effect of preventing contact between the circuit block 2 and the sealant can be enhanced.

(Embodiment 3)
Hereinafter, Embodiment 3 of the present invention will be described with reference to FIGS. Since the basic configuration of the third embodiment is the same as that of the first embodiment, common components are denoted by the same reference numerals and description thereof is omitted.

As shown in FIG. 7, the circuit block 2 according to the third embodiment is arranged in a direction (left and right direction in the drawing) orthogonal to the optical axis of the lens portion 5a by the side wall portion 4c on the opening side from the step portion 4d of the cap 4. It is characterized by being pinched. That is, the side wall portion 4c is similarly provided with another step portion 4g other than the step portion 4d, and the inner wall of the step portion 4g holds the circuit block 2. By this clamping, the circuit block 2 can be maintained at a position where the center of the light receiving surface of the infrared detecting element 1 and the optical axis of the lens portion 5a intersect. And the infrared detection range of the infrared detector is as shown in FIG.
Since it is in the detection zone 15 that expands outward in a fan shape with the lens portion 5a as the center, the infrared rays can be efficiently condensed on the light receiving surface via the lens portion 5a by maintaining the position in the above position.

For example, the side wall portion 4c formed so as to expand toward the opening side of the cap 4 may sandwich the circuit block 2 without providing the step portion 4g on the side wall portion 4c. . Also,
As described in the second embodiment, the circuit block 2 may be held by the side wall portion 4c while being in contact with the step portion 4d or the step portion 4f.

The infrared detector of Embodiment 1 of this invention is shown, (a) is a top view, (b) is sectional drawing. It is a disassembled perspective view in the same as the above. It is principal part sectional drawing in the same as the above. The infrared detector of Embodiment 2 of this invention is shown, (a) is a top view, (b) is sectional drawing. The infrared detector which has two step parts in the same as above is shown, (a) is a top view, (b) is sectional drawing. The infrared detector which has the step part which protrudes in the acute angle same as the above is shown, (a) is a top view, (b) is sectional drawing. The infrared detector of Embodiment 3 of this invention is shown, (a) is a top view, (b) is sectional drawing. It is a side view which shows the range which detects the infrared rays in the same as the above. An example of the conventional infrared detector is shown, (a) is a top view, (b) is a sectional view. The operation | work process which adheres a cover to the window part of an example of the conventional infrared detector is shown, (a) is the partial cross section perspective view which apply | coated the electrically conductive adhesive, (b) is the partial cross section which coat | covered the cover on the window part. A perspective view and (c) are partial cross-sectional perspective views into which sealing agent was poured. It is principal part sectional drawing of an example of the conventional infrared detector.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Infrared detector 2 Circuit block 3 Stem 4 Cap 4a Bottom part 4b Window part 4c Side wall part 4d Step part 5 Cover

Claims (3)

An infrared detection element, a circuit block provided with a signal processing circuit for processing a signal output from the infrared detection element, a stem formed in a plate shape on which the circuit block is placed on one side, and one end A translucent cap that is formed in an open bottomed cylindrical shape, houses the circuit block therein and is attached to the stem, and closes a window opening at the bottom of the cap that faces the infrared detection element. The cover includes a lens part that collects infrared rays on a light receiving surface of the infrared detection element, and a flange part that extends outward from the periphery of the lens part and is fixed to the periphery of the window part. The cap includes a stepped portion projecting inward along the entire circumference on the side wall near the bottom, and the gap between the cover and the window is sealed with a sealant. Red characterized by being stopped Line detector. The infrared detector according to claim 1, wherein the circuit block is in contact with the step portion in an optical axis direction of the lens unit. 3. The infrared detector according to claim 1, wherein the circuit block is held in a direction perpendicular to the optical axis of the lens unit by the side wall portion on the opening side of the stepped portion of the cap. .

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