JPH03273120A - Pyroelectric infrared detector - Google Patents

Abstract

PURPOSE:To facilitate the construction of a sensor circuit and to increase heat- insulation effect to a detecting element by connecting the detecting element to external lead terminals and fixing at a fixed position of the external lead terminals by caking conductive resin. CONSTITUTION:The detecting element 11 is fixed and supported stably on the three external lead terminals 19b-19d together with a circuit board 13 and the fitting position of the element 11 is freely set and fixed within the range of the length of the external lead terminals projecting on the board 13. The number of the external lead terminals which support the element 11 is not limited. Further, the lead terminal 10a which connects the photodetection electrode 11a of the element 11 to the circuit pattern of the board 13 is not lead out of a case 14, but when four holes for leading external lead terminals out are formed in the case 14, the terminal 19a is passed through the hole and held on the bottom plate 15 of the case 14. Then its outward projection end is covered with the insulating resin 21.

Description

[Detailed description of the invention] [Industrial Application Field J The present invention relates to the structure of a pyroelectric infrared detector.

[Prior Art] An electroless infrared detector utilizes, as a signal, a change in natural polarization caused by an A degree change in a pyroelectric material caused by absorption of infrared rays emitted from an object to be detected.

In a pyroelectric infrared detector, the pyroelectric element is made thin to about 50 to 100 μm to reduce heat capacity, and the detection sensitivity is improved by quickly responding to changes in infrared thermal energy.

4 to 7 show the support structure of a pyroelectric infrared detection element (hereinafter referred to as a detection element) used to prevent an increase in heat capacity. In each figure, l is a detection element, 1a is a light receiving electrode, I
b indicates a ground electrode, and 2 indicates an external lead terminal attached to the case 3. The detection element 1 is housed in a case 3 having a light-receiving window 4 together with a board on which electronic components constituting a circuit are mounted, but in each figure, the board on which child components 1a are mounted is not shown. . Figure 4 shows electrode 1 of detection element l.
a.

lb and the external lead terminal 2 are connected with the lead wire 5 to support the detection element l in the air. In the installed example shown in FIG. 6, a heat insulating pattern 8 is attached to a partially protruding insulating substrate 7 supported by an external lead terminal 2.
An example in which the detection element l is supported on a heat insulating pattern 8, and FIG. 7 shows an example in which the detection element l is installed on a perforated insulating substrate 9 attached to an external lead terminal 2.

[Problems to be Solved by the Invention] However, although the support structure shown in FIG. 4 is effective in preventing an increase in heat capacity, it lacks stability in supporting the detection element l, and also There is a problem in that it is difficult to handle and assemble due to its thinness. Although the support structure shown in FIG. 5 has excellent support stability for the detection element 1, the insulating substrate 7 does not have a sufficient heat insulating effect, and on the other hand, it has the drawback of increasing heat capacity and reducing sensitivity and responsiveness. be.

Furthermore, in the support structure shown in FIG. 6, it is difficult to make the heights of the heat insulation patterns 8 that partially protrude on the insulating substrate 7 uniform, so that the detection elements 1 may be mounted obliquely.
Furthermore, if the gap between the insulating substrate 7 and the detection element 1 is not aligned for each detector, the heat insulation effect will be different for each element, resulting in a disadvantage that the sensitivity and responsiveness of each detector will vary.

The support structure shown in FIG. 7 solves this drawback to a certain extent, but since it requires an area large enough to accommodate the detection element 1, there is a limit to the reduction in heat capacity. Although the back side of the insulating substrate 7 can be used as a mounting surface for electronic components such as resistors and FETs, the support structure shown in FIG. 7 reduces the planar area of the insulating substrate and saves mounting space. cannot be secured.

The fundamental cause C of the above-mentioned problem is also the manufacturing method of the detection element. The detector is usually made by the slicing method. In this method, a ferroelectric ceramic composition and particles are pressed into a columnar shape and fired at 1200°C, the resulting fired body is sliced into approximately 0.21M1 pieces, and 0.1ml is polished to form a sensing element. It is a method of finishing the material. When this Jj method number is reached, the finished element material has been sintered by firing, so it is almost impossible to drill holes in the material again.

Therefore, as long as an element material manufactured by the slicing method is used, the support structure shown in FIGS. 4 to 7 has no choice but to be used.

An object of the present invention is to solve the above-mentioned problems, to provide a sensor circuit that is easy to construct, has high strength against external vibrations and shocks, and
An object of the present invention is to provide a pyroelectric infrared detector that has a large heat insulation effect on a detection element.

[Means for Solving the Problems] In order to achieve the above object, in the pyroelectric infrared detector according to the present invention, a circuit board on which electronic components constituting a circuit are mounted and an infrared detecting element are It is an electric type infrared detector, and has multiple external lead terminals, the external lead terminal is for electrically connecting the electronic component or the infrared detection element to the external circuit, and the detection element is for connecting the element to the external circuit. A plurality of mounting holes or notches are formed through the surface, and the external lead terminal supports the circuit board and is inserted into the mounting hole or notch made in the detection element. It is electrically connected to the external lead terminal using a conductive exterior resin adhesive and is held at a fixed position on the external lead terminal.

[Function] In the present invention, unlike the conventional slicing method, the particles of the ferroelectric element composition are formed in advance into a sheet shape with a thickness of approximately 0°2 and then punched out using a press to form external lead terminals. After opening the mounting hole [1] and cutting it into a predetermined shape, it is fired at about 1200°C to sinter it. I
The element material is polished to a thickness of gw. FIG. 2 shows the obtained infrared detection element.

The detection element 11 is plate-shaped and has mounting holes 1 for external lead terminals at each corner.
2a to +2d, and the - side has the light receiving 'Wl pole 11a,
On the other side, a pattern of ground electrodes 11b is provided extending around the mounting holes 12a, 12b of the respective pairs of external lead terminals.

In the present invention, an external lead terminal is inserted into each mounting hole of the detection element and sealed with a conductive resin to support the detection element at a fixed position of the external lead terminal. In the pyroelectric infrared detector according to the present invention, since the detection element is directly held on the external lead terminal, the support stability and support strength of the detection element are high, and the circuit board and the detection element are also attached to the external lead terminal. By forming a gap therebetween, heat insulation can be easily ensured, and at the same time, the circuit board and the detection element can be electrically connected using external lead terminals.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 shows an infrared detection element manufactured by the sheet method. Detection element II is in the example.

It is a rectangular plate-like body, and mounting holes +2a-12d are opened at the four corners. On one surface of the detection element 11, a light receiving electrode 11a,
A pattern of ground electrodes 11b is provided on the other surface, and each pattern extends to one corner surrounding the corresponding mounting holes 12a and +2b.

In FIG. 1, the pyroelectric infrared detector has an infrared detection element 11 and a circuit board I3 mounted with electronic components constituting a circuit built into a case 14. Case! 4 covers the bottom plate 15 with a cover 16, and a light receiving window +6a is formed in a part of the upper surface of the cover 16. Circuit board! 3 is a plate-shaped body made of alumina porcelain;
The wiring pattern formed on the substrate 13 includes a resistor 17.
It is equipped with a semiconductor element 18 and the like.

The three external lead terminals 19b, 19c, 19d are supported by the bottom plate 15 of the case 14, and the circuit board 13 has three external lead terminals +9b, +9c, which protrude above the bottom plate 15.
19d and is held in place by conductive resin. The detection element 11 is installed above the substrate 13 with the light receiving electrode 11a facing the light receiving window 16a of the case 14. Each mounting hole 1.2a provided in the detection element 11
The opening position of +2d corresponds to the support position of the board by the external lead terminal, and the detection element 11 has each external lead terminal protruding onto the board 13 in its mounting holes 12b, +2c, and 12d! 9b, 19c, 19d are inserted, external lead terminals +9b, +9c, 19d
A conductive resin adhesive 20 applied between the detection element 11 and the detection element 11 fixes the detection element 11 in a fixed position on the substrate 13. Although the distance 11 between the substrate 13 and the detection element 11 is not particularly limited, it is appropriate to set it to a height of 50 μm or more.

The above three external lead terminals 19b, +9c, 19d
In the case of the embodiment, these are the input/output terminals and the ground terminal of the infrared detector, but a separate lead is provided in the mounting hole 12a around which the pattern of the terminal of the light-receiving electrode lea of the detection element 11 is attached. Insert the terminal +9a into the mounting hole 12a that leads to the circuit pattern of the corresponding circuit board 13, and fix it with conductive resin adhesive 20 to connect the circuit pattern of the board 13 and the pattern of the light receiving electrode +1a of the detection element. and conduct each other. The ground electrode 11b for the detection element is connected to the external lead wire 1 together with the ground electrode pattern of the circuit board 13.
It is directly electrically connected to 9b.

In addition, if necessary, the lead wire 11a connecting the detection element 11 and the wiring pattern of the board 13 and the bottom plate 1 of the case 14
Insulating resin 2I may be interposed between 5 and 5.

Further, the mounting hole is not limited to a completely circular shape, and may have a partially open end edge, or a shape in which a lead terminal is locked, for example, a portion of a corner may be cut out.

In the above embodiment, the detection element 11 has three external lead terminals 19b, 19c, and 19d together with the circuit board 13.
The mounting position of the detection element II can be set and fixed at the zero peak within the length range of the external lead terminal protruding onto the circuit board 13.

The number of external lead terminals supporting the detection element 11 is not limited. In the embodiment, the light receiving m of the detection element 11
The lead terminal +9a that connects the pole 11a and the circuit pattern of the circuit board 13 is not drawn out of the case 14, but when the case 14 has four holes for drawing out external lead terminals, Lead terminal inside this hole as shown in Figure 3! 9a is pushed through and held on the bottom plate 15 of the case 14, and its outwardly protruding end is inserted into the insulating resin 21.
It may be further covered with conductive resin 22 as a noise countermeasure.

[Effects of the Invention] As described above, according to the present invention, the detection element is passed through the external lead terminal provided in the infrared detector, and is fixed in the fixed position of the external lead terminal by solidifying it with a conductive resin. The element can be stably supported, and the conductive resin acts as a buffer against external vibrations and shocks, so the sensing element is not affected.
Further, by adjusting the spacing between the detection element and the circuit board, it is possible to secure the spacing necessary for heat insulation of the detection element. According to the present invention, the construction of the sensor circuit is easy and the quality is high.

It has the effect of mass producing products with uniform performance.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a pyroelectric infrared detector showing one embodiment of the present invention, Fig. 2 is a plan view of a detection element, and Fig. 3 is a pyroelectric infrared detector showing another embodiment of the invention. 4 to 7 are cross-sectional views showing conventional examples of pyroelectric infrared detectors. 11...Detection element 12a~! 2d...Mounting hole 13...Circuit board 14...Case 1
9b -+9d...External lead terminal 20...Conductive resin adhesive Fig. 2

Claims (1)

[Claims] (1) A circuit board equipped with electronic components that make up the circuit,
A pyroelectric infrared detector having an infrared detection element, having a plurality of external lead terminals, the external lead terminals electrically connecting the electronic component or the infrared detection element to an external circuit, The detection element has multiple mounting holes or notches formed through the element surface, and the external lead terminals support the circuit board and are inserted into the mounting holes or notches made in the detection element. A pyroelectric infrared detector, characterized in that the detection element is electrically connected to an external lead terminal using a conductive resin adhesive and is held at a fixed position on the external lead terminal.