JP6043828B2 - Pyroelectric infrared sensor - Google Patents

Description

  The present invention relates to a pyroelectric infrared sensor.

  In Patent Document 1, a first spacer made of a multilayer printed circuit board having a hollow structure is stacked on a base on which a circuit element is mounted, and a pyroelectric sensor element is installed on the first spacer. A pyroelectric infrared sensor that secures a space for mounting circuit elements below is disclosed. A metal film layer is formed on the inner side surface of the first spacer. In this metal film layer, a cut is formed so as to make both the poles of the pyroelectric sensor element conductive to the base.

JP2013-50359A

  In the configuration of Patent Document 1, since there is a cut in the metal film layer formed on the inner side surface of the first spacer, the pyroelectric sensor element is contaminated by gas and dust generated on the inner side surface of the first spacer. There is a fear.

  The objective of this invention is providing the technique which suppresses that a pyroelectric sensor element is contaminated.

According to an aspect of the present invention, a base substrate, a pyroelectric sensor element mounted on the base substrate, and a cylindrical frame body mounted on the base substrate and surrounding the pyroelectric sensor element are provided. There is provided a pyroelectric infrared sensor in which a metal film is formed over the entire inner side surface of the frame. According to the above configuration, since the pyroelectric sensor element is mounted on the base substrate, the metal film can be formed seamlessly across the entire inner side surface of the frame. Become. Further, since the metal film is formed over the entire area of the inner side surface of the frame body, the pyroelectric sensor element is prevented from being contaminated by gas or dust generated on the inner side surface of the frame body. be able to.
An electrode to which the pyroelectric sensor element is electrically connected is formed on the base substrate, and a bump is interposed between the electrode and the pyroelectric sensor element. According to the above configuration, since a gap is secured between the base substrate and the pyroelectric sensor element, the pyroelectric sensor element moves away from the base substrate, and thus the pyroelectric due to heat generation of the base substrate itself. A decrease in sensitivity of the sensor element can be suppressed.
The base substrate has a metal film that spreads outside the inner side surface of the frame. According to the above configuration, the electromagnetic noise resistance of the pyroelectric sensor element is improved.
The pyroelectric sensor element is disposed substantially at the center of the base substrate. According to the above configuration, the viewing angle of the pyroelectric sensor element can be effectively ensured.

  According to the present invention, since the metal film is formed over the entire area of the inner side surface of the frame body, the pyroelectric sensor element is contaminated by gas and dust generated on the inner side surface of the frame body. Can be suppressed.

It is a disassembled perspective view of a pyroelectric infrared sensor. It is sectional drawing of a pyroelectric infrared sensor.

  Hereinafter, the pyroelectric infrared sensor 1 will be described with reference to FIGS. 1 and 2.

  As shown in FIG. 1, the pyroelectric infrared sensor 1 includes an element housing 2, a pyroelectric sensor element 3, a circuit component 4, and an optical filter 5.

  The element housing 2 houses the pyroelectric sensor element 3 and the circuit component 4. As shown in FIG. 2, the element housing 2 includes a base substrate 6 and a cylindrical frame body 7.

  The base substrate 6 is composed of a multilayer printed board. The base substrate 6 includes an element mounting surface 8 and a bottom surface 9 that is a surface opposite to the element mounting surface 8. The base substrate 6 has a metal film 11 that spreads outside the inner side surface 10 of the frame 7 in plan view. The metal film 11 is embedded in the base substrate 6. At least three electrodes 12 are formed on the bottom surface 9 of the base substrate 6. Two element electrodes 19 are formed on the element mounting surface 8 of the base substrate 6.

  The frame body 7 is composed of a multilayer printed circuit board. The frame body 7 is formed in a rectangular tube shape. The frame body 7 is mounted on the element mounting surface 8 of the base substrate 6. The frame 7 has the inner side surface 10, the optical filter mounting surface 13, and the base facing surface 14. The base facing surface 14 is a surface facing the base substrate 6. The optical filter mounting surface 13 is a surface opposite to the base facing surface 14. A metal film 15 (metal film) such as copper plating is formed over the entire area of the inner side surface 10 of the frame 7. The metal film 15 is formed in an annular shape without a break. Since the metal film 15 is formed in an annular shape without a break, the shielding effect for the pyroelectric sensor element 3 is exhibited at a high level. In addition to the inner side surface 10, the metal film 15 is also formed on the optical filter mounting surface 13 and the base facing surface 14. Therefore, the cross-sectional shape of the inner side surface 10 is substantially U-shaped. The thickness of the metal film 15 is preferably 10 to 100 micrometers, for example. The metal film 15 is not formed in a region outside the optical filter mounting surface 13. In other words, the optical filter mounting surface 13 is exposed in the outer region. An annular resist 16 is formed on the optical filter mounting surface 13. The resist 16 is formed on the exposed portion of the optical filter mounting surface 13.

  The optical filter 5 is mounted on the optical filter mounting surface 13 of the frame body 7 using a conductive adhesive 17. Specifically, the optical filter 5 is mounted on the optical filter mounting surface 13 via the adhesive 17 and the metal film 15. The optical filter 5 is positioned in the horizontal direction by the annular resist 16. The adhesive 17 does not flow outward due to the presence of the annular resist 16. A sealing resin 18 is filled between the optical filter 5 and the resist 16. Further, due to the presence of the annular resist 16, high sealing performance of the pyroelectric infrared sensor 1 is realized.

  The pyroelectric sensor element 3 and the circuit component 4 are mounted on the element mounting surface 8 of the base substrate 6. Since the pyroelectric sensor element 3 and the circuit component 4 are mounted on the same element mounting surface 8, it contributes to a reduction in the height of the pyroelectric infrared sensor 1.

  The pyroelectric sensor element 3 is mounted via two bumps 20 on two element electrodes 19 (electrodes) formed on the element mounting surface 8 of the base substrate 6. The bump 20 is formed, for example, by overlapping copper plating several times. The bump 20 preferably has a thickness of, for example, 50 to 200 micrometers or more. Due to the presence of the bump 20, a gap 21 is formed between the pyroelectric sensor element 3 and the element mounting surface 8 of the base substrate 6. Due to the presence of the air gap 21, the sensitivity of the pyroelectric sensor element 3 due to heat transfer to the base substrate 6 is suppressed. In addition, the pyroelectric sensor element 3 is disposed substantially at the center of the base substrate 6. Therefore, the viewing angle θ of the pyroelectric sensor element 3 can be effectively ensured. The circuit component 4 is an FET or a resistance element. The circuit component 4 is disposed around the pyroelectric sensor element 3.

  As a manufacturing procedure of the pyroelectric infrared sensor 1, first, the circuit component 4 is mounted on the base substrate 6, and then the pyroelectric sensor element 3 is mounted. Next, the frame body 7 is bonded to the base substrate 6. Then, after mounting the optical filter 5 on the frame body 7, the sealing resin 18 is filled. A plurality of pyroelectric infrared sensors 1 can be manufactured simultaneously. Finally, the pyroelectric infrared sensor 1 is separated. The pyroelectric infrared sensor 1 is easy to manufacture because each component can be stacked in order from the bottom.

  Further, if the optical filter 5 is to be bonded to the metal film 15 of the frame body 7, the bonding surface may be weakened due to environmental changes such as temperature change and humidity change. On the other hand, in the present embodiment, the metal film 15 is not formed over the entire area of the optical filter mounting surface 13 of the frame body 7, but the outer peripheral region of the optical filter mounting surface 13 is intentionally exposed without forming the metal film 15. I am doing so. Accordingly, the adhesiveness between the optical filter 5 and the frame 7, the airtightness of the pyroelectric infrared sensor 1, and the electrical connection between the optical filter 5 and the frame 7 are satisfied at the same time.

  The preferred embodiment of the present application has been described above. The above embodiment has the following features.

  The pyroelectric infrared sensor 1 includes a base substrate 6, a pyroelectric sensor element 3 mounted on the base substrate 6, and a cylindrical frame 7 mounted on the base substrate 6 and surrounding the pyroelectric sensor element 3. . A metal film 15 is formed over the entire inner side surface 10 of the frame body 7. According to the above configuration, since the pyroelectric sensor element 3 is mounted on the base substrate 6, the metal film 15 can be formed seamlessly across the entire inner side surface 10 of the frame body 7. Become. Further, since the metal film 15 is formed over the entire area of the inner side surface 10 of the frame body 7, the pyroelectric sensor element 3 is prevented from being contaminated by gas or dust generated on the inner side surface 10 of the frame body 7. be able to.

  An element electrode 19 (electrode) to which the pyroelectric sensor element 3 is electrically connected is formed on the base substrate 6. A bump 20 is interposed between the element electrode 19 and the pyroelectric sensor element 3. According to the above configuration, since the air gap 21 (gap) is secured between the base substrate 6 and the pyroelectric sensor element 3, the pyroelectric sensor element 3 moves away from the base substrate 6 and thus heat to the base substrate 6 is obtained. A decrease in sensitivity of the pyroelectric sensor element 3 due to transmission can be suppressed.

  The base substrate 6 has a metal film 15 that spreads outside the inner side surface 10 of the frame body 7. According to the above configuration, the electromagnetic noise resistance of the pyroelectric sensor element 3 is improved.

  The pyroelectric sensor element 3 is disposed substantially at the center of the base substrate 6. According to the above configuration, the viewing angle θ of the pyroelectric sensor element 3 can be effectively ensured.

  Moreover, in the said embodiment, since the pyroelectric sensor element 3 is mounted on the base substrate 6, it contributes to the low profile of the pyroelectric infrared sensor 1. FIG.

DESCRIPTION OF SYMBOLS 1 Pyroelectric infrared sensor 2 Element container 3 Pyroelectric sensor element 4 Circuit component 5 Optical filter 6 Base board 7 Frame body 8 Element mounting surface 9 Bottom surface 10 Inner side surface 11 Metal layer 12 Electrode 13 Optical filter mounting surface 14 Base facing surface 15 Metal film 16 Resist 17 Adhesive 18 Sealing resin 19 Element electrode 20 Bump 21 Gap

Claims (4)

A base substrate;
A pyroelectric sensor element mounted on the base substrate;
A cylindrical frame mounted on the base substrate and surrounding the pyroelectric sensor element;
With
The frame is composed of a multilayer printed board,
A metal film is formed on the entire inner side surface of the frame body, a base facing surface that is a surface facing the base substrate of the frame body, and an optical filter mounting surface that is a surface opposite to the base facing surface of the frame body. Being
Pyroelectric infrared sensor. The pyroelectric infrared sensor according to claim 1,
The base substrate is formed with an electrode to which the pyroelectric sensor element is electrically connected,
A bump is formed between the electrode and the pyroelectric sensor element.
Pyroelectric infrared sensor. The pyroelectric infrared sensor according to claim 1 or 2,
The base substrate has a metal film that spreads outside the inner side surface of the frame,
Pyroelectric infrared sensor. The pyroelectric infrared sensor according to any one of claims 1 to 3,
The pyroelectric sensor element is disposed substantially at the center of the base substrate.
Pyroelectric infrared sensor.

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