JP2963348B2 - Pyroelectric sensor element and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pyroelectric sensor element for converting infrared rays into an electric signal by utilizing a pyroelectric effect, a method of manufacturing the same, and a pyroelectric sensor device.

[0002]

2. Description of the Related Art Conventionally, for example, a so-called dual type of pyroelectric infrared sensor element is shown in FIG.
A concave-shaped electrode 2 is deposited in a matrix on the surface of a ceramic substrate 1 having a pyroelectric effect, and electrodes 3 are deposited on the rear surface of the concave-shaped electrode 2 corresponding to both ends, respectively. After these electrodes were formed, the sensor element 5 was formed by dividing the electrode 2 by the dividing line 4. This sensor element 5 is about 5 m
It was housed in a case having an m-square and having a light-receiving window together with an FET or the like for converting an output signal from the sensor element into an impedance.

[0003]

However, in the case of the above conventional technique, it cannot be said that the sensor element 5 is formed efficiently from the ceramic substrate 1 on which the sensor element 5 is formed, and the sensor element itself is useless. There was space. Therefore, the use efficiency of the ceramic substrate 1 is poor, which hinders miniaturization and cost reduction of the sensor element.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and a pyroelectric sensor element capable of efficiently forming a small sensor element with a simple structure, a method of manufacturing the same, and a pyroelectric element. It is an object to provide a sensor device.

[0005]

According to the present invention, a metal thin film is formed on the surface of a rectangular sensor substrate such as PZT having a pyroelectric effect by slightly opening both ends on the short side of the rectangle. On the back surface, the metal thin film is divided at the center of the substrate so that the metal thin film on the front side is partially separated from the metal thin film by sandwiching the sensor substrate. It is a formed pyroelectric sensor element.

Further, according to the present invention, a metal thin film is formed in a stripe shape at a predetermined interval on the surface of a substrate having a pyroelectric effect, and a metal thin film is similarly formed in a stripe shape at a predetermined interval on the back surface.
A metal thin film on the front surface and a metal thin film on the back surface are formed at positions facing each other between the stripes, and the substrate is divided in parallel with the metal thin film at a portion between the metal thin films on the front surface to form a back surface. The metal thin film on the side is divided into two parts, and the substrate is also divided in a direction perpendicular to the longitudinal direction of the metal thin film, and the side in the longitudinal direction of the metal thin film becomes a short side after the division. This is a method for manufacturing a pyroelectric sensor element that forms a rectangular sensor element. In addition, the present invention includes the above-described pyroelectric sensor element housed in a disk-shaped metal bottom plate constituting a case body and a cylindrical metal cap covering the same, and the metal cap has an upper surface center. A pyroelectric sensor device in which a light receiving window is formed in the portion, an infrared incident filter is attached to the light receiving window, the sensor element is supported by a support in the cap, and electrical connection with a circuit board is achieved. It is.

[0007]

The pyroelectric sensor element and the method of manufacturing the same according to the present invention
A large number of pyroelectric sensor elements can be efficiently divided from a single substrate, and the sensor element itself can be reduced in size.

[0008]

An embodiment of the present invention will be described below with reference to the drawings. In the pyroelectric sensor element 5 of this embodiment, as shown in FIGS. 1 and 2, a metal thin film 7 of Ni, Cr or Ag is formed on the surface of a sensor substrate 6 made of a ferroelectric ceramic such as PZT or PT. ing. This metal thin film 7 is shown in FIG.
As shown in (A), the rectangular sensor substrate 6 is formed with both short-side end portions left. On the back surface of the sensor substrate 6, as shown in FIG. 1 (B), a metal thin film 8 which is an electrode independent from each other is formed at both ends on the short side of the rectangle with the substrate center partly opened. I have. This sensor substrate 6
Has a ratio of long side to short piece of about 2: 1.

The method of manufacturing the pyroelectric sensor element 5 is as follows. First, a ceramic substrate 1 for dividing and obtaining a large number of sensor elements 5 is formed and subjected to a polarization treatment. The metal thin film 7 is deposited on the mask 30 shown in FIG. Similarly, a metal thin film 8 as an electrode material is deposited on the back surface using the mask 32 shown in FIG. Openings 34 and 36 for forming the metal thin films 7 and 8 are formed in the masks 30 and 32, respectively, and a positioning through hole 38 is also formed in each. Thus, the metal thin films 7 and 8 are formed at predetermined intervals in a stripe shape. The metal thin films 7 and 8 are formed at positions where the metal thin film 7 on the front surface and the metal thin film 8 on the rear surface face each other in the gap between the stripes.

[0010] Thereafter, the substrate 1 is divided into individual sensor elements 5. The dividing method is to divide the metal thin film 7 at a portion between the metal thin films 7 on the front surface side in parallel with the metal thin film 7 and
Is divided into two. At the same time, the substrate 1 is divided also in the direction perpendicular to the longitudinal direction of the metal thin film 7,
As shown in FIG. 1, the sensor element 5 after division is formed in a rectangular shape in which the long sides of the metal thin films 7 and 8 are short sides.

A pyroelectric sensor element 5 according to this embodiment is shown in FIG.
As shown in FIG. 6, the case body is housed in a hermetic base 10, which is a disk-shaped metal bottom plate constituting a case body, and a cylindrical hermetic metal cap 12 covering the same. A light receiving window 16 is formed at the center of the upper surface of the cap 12, and the light receiving window 16 has an infrared incident filter 17.
Is attached.

A ceramic substrate 20 shown in FIGS. 5 and 6 is mounted on the hermetic base 10, and a resistor 21 and an FET 22 are soldered to a circuit pattern 18 formed on the surface of the ceramic substrate 20. Installed. Further, on the ceramic substrate 20, the base ends of a pair of metal columns 24 supporting the sensor element 5 are fixed by solder and connected to the circuit pattern 18.
The column 24 is, for example, solder plated on a copper round bar, supports the sensor element 5 with the two columns 24, and also achieves electrical connection between the sensor element 5 and the ceramic substrate 20. . The sensor element 5 is mounted on the tip of the support post 24 and is fixed by, for example, a conductive adhesive 26 in which silver or the like is mixed with an epoxy resin.

Three lead terminals 28 penetrate the periphery of the hermetic base 10 and the ceramic substrate 20. The lead terminal 28 is connected to the support 2 supporting the sensor element 5.
4, which penetrates through the hermetic base 10 and the ceramic substrate 20, and whose tip is connected to the circuit pattern 18 on the ceramic substrate 20 by solder 30 and is fixed to the ceramic substrate 20. And
It is connected to the FET 22 and the like on the ceramic substrate 20 via the circuit pattern 18 on the ceramic substrate 20.

The periphery of the cap 12 is resistance-welded to the periphery of the hermetic base 10 to completely seal the inside. Then, the inside of the case body is filled with nitrogen gas, and the influence of the characteristic change due to the change of the external environment is suppressed.

The operation of the pyroelectric sensor element of this embodiment is as follows. First, when there is no infrared radiator in the field of view of the sensor element 5,
The output signal from the sensor element 5 is only noise, and no detection signal is output. On the other hand, when an infrared radiator such as a person passes through the field of view of the sensor element 5, the output signal from the sensor element 5 swings positive and negative when a person enters and exits, respectively. Then, a detection signal whose impedance has been converted to a predetermined level by the FET 22 is output from the lead terminal 28.

According to the pyroelectric sensor element of this embodiment, the sensor element 5 can be efficiently divided from the ceramic substrate 1 to obtain a large number, and the pyroelectric sensor element 5 can be obtained from one ceramic substrate 1. Significantly increases the number of sensors, which contributes to cost reduction, and also greatly contributes to downsizing of the sensor device. Note that the size of the sensor element 5 can be appropriately selected, and the number, shape, or width of the metal thin film serving as an electrode can be appropriately set.

Next, another embodiment of the pyroelectric sensor element of the present invention will be described with reference to FIG. Here, the same members as those in the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted.
In this embodiment, a rectangular sensor substrate 6 having a pyroelectric effect is used.
A metal thin film 7 is formed on a part of the surface of the sensor substrate 6, and an electrode of the metal thin film 8 is formed on the back surface of the sensor substrate 6 at a position facing the metal thin film 7 with the sensor substrate 6 interposed therebetween. The metal thin films 7 and 8 need only be at least partially overlapped on the front and back surfaces with the sensor substrate 6 interposed therebetween, and the size and number thereof can be set as appropriate.

In the method of manufacturing a pyroelectric sensor element according to this embodiment, a metal thin film 7 is formed in stripes at predetermined intervals on the surface of a substrate 1 having a pyroelectric effect, and likewise on the back surface in stripes at predetermined intervals. A metal thin film 8 is formed. At this time, the metal thin film 7 on the front surface and the metal thin film 8 on the back surface are formed so that a part thereof faces each other with the sensor substrate 6 interposed therebetween. Then, the metal thin films 7 and 8 are each divided in a direction parallel to the longitudinal direction of the stripes of the metal thin films 7 and 8. Further, the substrate 1 is divided also in the direction perpendicular to the longitudinal direction of the metal thin films 7, 8 to form a rectangular sensor element 5 in which the longitudinal sides of the metal thin films 7, 8 are short sides in the divided state. .

With the pyroelectric sensor element of this embodiment, the same effects as those of the above embodiment can be obtained, and the present invention can be applied to pyroelectric sensor elements other than the dual type.

[0020]

According to the pyroelectric sensor element of the present invention, it is possible to divide a large number of sensor elements from a multi-piece substrate and obtain a large number of sensor elements with a simple structure. The size can also be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a front surface (A) and a back surface (B) of a pyroelectric sensor element according to an embodiment of the present invention.

FIG. 2 is a partially cutaway plan view of a ceramic substrate for obtaining a pyroelectric sensor element of this embodiment.

FIG. 3 is a plan view of a mask for vapor deposition on the front surface side to obtain a pyroelectric sensor element of this embodiment.

FIG. 4 is a plan view of a vapor deposition mask on the back surface side for obtaining the pyroelectric sensor element of this embodiment.

FIG. 5 is a perspective view of a sensor device to which the pyroelectric sensor element of this embodiment is attached.

FIG. 6 is a longitudinal sectional view of the pyroelectric sensor device of the embodiment.

FIG. 7 is a plan view of a pyroelectric sensor element according to another embodiment of the present invention.

FIG. 8 is a plan view of a conventional pyroelectric sensor element.

[Explanation of symbols]

 Reference Signs List 1 substrate 5 sensor element 6 sensor substrate 7, 8 metal thin film

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-187918 (JP, A) JP-A-58-66828 (JP, A) JP-A-6-147979 (JP, A) JP-A-Heisei 4- 116430 (JP, A) JP-A-61-88118 (JP, A) JP-A-4-59428 (JP, U) JP-A-2-141833 (JP, U) JP-A-4-59428 (JP, U) Hikaru 4-116373 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) G01J 1/02 G01J 5/02

Claims (4)

(57) [Claims] 1. A metal thin film is formed on the entire surface of a rectangular sensor substrate having a pyroelectric effect at both longitudinal ends thereof,
On the back side of this sensor board, the longitudinal direction of this sensor board
A pyroelectric sensor element in which electrodes are formed by a pair of metal thin films spaced apart from each other at a central portion . 2. A rectangular sensor substrate with a pyroelectric effect one
One end in the longitudinal direction on one side
Is formed on the other surface, and the one surface is formed on the other surface.
Open the other end opposite to the end
Pyroelectric sensor element with poles formed . Wherein the individual sensor element substrate with a pyroelectric effect
A metal thin film is formed in stripes at predetermined intervals on the surface of the large substrate to be divided, and a metal thin film is also formed in stripes at predetermined intervals on the back surface. portions of which face each other across the sensor substrate, the substrate, a metal thin film of the surface-side stripe
The metal thin film on the back side between
At the dividing position, when dividing in the longitudinal direction for each metal thin film
In both cases, the substrate is also divided in a direction perpendicular to the longitudinal direction of the metal thin film, and after being divided into individual sensor element substrates ,
Longitudinal sides of the metal thin film on the substrate of the large-size, the
A method for manufacturing a pyroelectric sensor element that divides a sensor element substrate so as to be a short side thereof . 4. The method according to claim 1, wherein each of the sensor element substrates having a pyroelectric effect is
The metal thin film is formed in a stripe pattern at predetermined intervals in the divided large substrate surface is likewise a metal thin film is formed in a stripe pattern at predetermined intervals on the back surface, and a metal thin film of a metal thin film and the back surface of the surface to each other Perpendicular to the longitudinal direction of each stripe
This large substrate, which is formed facing each other with a shift in the angular direction ,
Between the metal thin film on the front side and the metal thin film next to it
Part is alternately cut in the longitudinal direction, the substrate is also divided in a direction perpendicular to the longitudinal direction of the metal thin film, and the individual sensor element bases are divided.
In the state after being divided into plates, the long side of the metal thin film on the large substrate is a short side of the sensor element substrate.
Method for manufacturing a pyroelectric sensor element that is divided as follows .