JPS59183341A - Manufacture of pyroelectric infrared sensor - Google Patents

Abstract

PURPOSE:To obtain a small-sized and low-cost sensor by a construction wherein the upper and lateral sides of a pyroelectric body provided with electrodes on both surfaces and disposed on a printed circuit board and the printed circuit board itself are covered with a subliming agent, an infrared long-pass filter slightly larger than the pyroelectric body is positioned with insulating resin, and the entire device is covered and heated. CONSTITUTION:A printed circuit board 2 to which EFT4 is connected and fixed is connected and fixed on the tops of terminals 3 buried in a base 5, and a pyroelectric body 1 having electrodes on both surfaces is disposed on the board 2. Then, a subliming agent 8, such as paraffin or wax, which is a (semi-)solid at normal temperature and is dissolved by heating is applied to cover the upper and lateral sides of the pyroelectric body 1 and the board 2 therewith. Next, an infrared long-pass filter 10 slightly larger (an angle or a diameter of 3-4mm.) than the pyroelectric body 1 (a 2mm. square) is positioned with insulating resin 9, and the entire device is covered with resin and cured. When or after it is cured, the entire device is heated to the sublimation temperature of the subliming agent 8, whereby the subliming agent 8 is made to sublime outside to be removed through innumerable pores in the resin 9. According to this construction, a visual field angle is maintained sufficiently even with the small filter 10, and thus a low-cost and small-sized sensor is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The industrial field of application is to reduce the amount of infrared radiation emitted from a single object by reducing the amount of infrared radiation emitted from a single object. This article relates to the manufacturing capacity of pyroelectric infrared sensors that are used as blowfish sensors.

Structure of a conventional example and its problems A conventional pyroelectric infrared sensor is structured as shown in FIG. 1 is a pyroelectric material, generally nickel, which has a high infrared absorption rate on the energy incidence surface.

A chromium alloy electrode is formed by vapor deposition or the like, and an aluminum electrode that reflects infrared rays is formed on the opposite side. Reference numeral 2 denotes a printed circuit board having a copper foil, on which the pyroelectric body 1 is disposed, and is connected to each terminal 3 by the steel Nfd soldering.

Reference numeral 4 denotes a field effect transistor (FET) with high input impedance for increasing the charge generated in the pyroelectric body 1. 5 is a base 1, 6 in which the terminal 3 is embedded;
is a metal cap, and an infrared long-pass filter 7 for cutting wavelengths in a specific region is fixed to the inside of the cap 6.

In this case, an infrared long-pass filter is required that is larger than the size of the infrared incident window of the metal cap = a. Generally, the size of the infrared incident window is 4 to 6 myhφ, and the thickness of the infrared long-pass filter is 6 to 7 mm, or 6 to 7 m.
It is m4j. Infrared long-pass filters are generally made by depositing several dozen layers of semiconductor material on a germanium or /licon substrate, so they are expensive. As a result, the cost of the pyroelectric infrared sensor has increased, which is one drawback.

To improve this, efforts have been made to reduce the cost of pyroelectric infrared sensors by reducing the size of the infrared entrance window in the metal cage and by reducing the dimensions of the infrared long filter to reduce the amount used. ing.

However, in this case, a new problem occurred in that the viewing angle became narrower, and the user needed to devise a new problem.

Purpose of the Invention The present invention: ・This invention eliminates the drawbacks of the conventional technology.
It is an object of the present invention to provide a thermoformed infrared sensor that can greatly reduce the amount of infrared long-pass filter used, reduce the cost of a pyroelectric infrared sensor, and secure a viewing angle.

1. Preparation of the Invention In order to achieve this object, the method for manufacturing a pyroelectric infrared sensor of the present invention includes coating the space between the pyroelectric material and the infrared long filter with a sublimating agent such as paraffin or wax. After positioning and molding an infrared long-pass filter, which is slightly larger than a pyroelectric material, with an insulating resin, when heating the insulating resin to harden it, the sublimating agent is sublimated through the countless pores in the insulating resin, and the pyroelectric material is heated. A gap is formed between the body and the insulating resin.

This manufacturing method allows the infrared aperture/green space to be reduced. In other words, the size of a typical Ejiaotun tree is about 2 mouths, so the infrared long filter is 3 to 48 cm.
It becomes possible to make the size Ll or 3 to 4 mmφ, and the amount of infrared rays required is about half that of the conventional infrared long filter.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. In FIG. 2, parts that are the same as those in FIG. 1 are given the same numbers.

Terminal 3 of base 5 where terminal 3 is buried
A printed circuit board 2 having copper foil on the front and back sides is connected and fixed to the upper part by soldering. Terminals of a field effect transistor (NET) 4 are connected and fixed to the lower part of the printed circuit board 2 by soldering. The upper part of the printed circuit board 2 is provided with electrodes on both sides, and the pyroelectric body 1 is connected and fixed with a conductive adhesive. In this state, a sublimating agent 8, which is solid or semi-solid at room temperature and easily melts when heated, is applied around the pyroelectric body 1, printed circuit board 2, and FET 4, and then a small infrared long-pass filter is formed. 10
The infrared long pass filter 10'7) is positioned on the upper surface of the pyroelectric body 1, and an insulating resin layer 9 is formed to form an overall coating, and this insulating resin layer 9 is cured. When formed, the insulating resin layer ζ is formed in the form 9, pyroelectric body 1, printed circuit board 2, FET 4
form a gap between them.

By such a manufacturing method, it is possible to obtain a pyroelectric infrared sensor that can drastically reduce the amount of infrared long-pass filters used, secure a viewing angle, and be miniaturized.

Effects of the Invention As described above, according to the method for manufacturing a pyroelectric infrared sensor of the present invention, the amount of infrared long-pass filter used can be drastically reduced.
It is possible to reduce the cost of pyroelectric infrared rays. In addition, the pyroelectric type has the advantage that it does not have the disadvantage of narrowing the viewing angle due to the reduction in the size of the infrared incident window in order to reduce the amount of infrared long-pass filter used in the past. We can provide infrared sensors.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a conventional pyroelectric infrared sensor;
FIG. 1d is a g-plane view showing the entire pyroelectric infrared sensor in the process of being manufactured in the manufacturing method of the present invention. 1 Focused body, 2 Printed circuit board, 8- Sublimation agent, 9
-~Insulating resin layer, 10- Infrared long pass filter. Name of agent - FP Physician Toshio Nakao and one other person Figure 1 q Figure 2

Claims (1)

[Claims] A pyroelectric body with electrodes on both sides is placed on a printed circuit board,
Said Jiao? A coating is formed on the top and side surfaces of body A with a sublimating agent such as paraffin or wax, and an insulating resin is used to position the infrared long-pass filter, forming a complete cover. The sublimating agent is used for 1121 months, and it sublimates through the pores of the sublimation agent. How to manufacture the sensor.