JPS5872016A - Pyroelectric infrared sensor - Google Patents

Abstract

PURPOSE:To obtain a pyroelectric type IR sensor of simple constitution having high reliability by constituting the same in such a way that a reflection plate is formed into a tray shape projecting downward in the central part, a pyroelectric film is sandwiched by the circumferential edge of the reflection plate and an earth ring, and the film is connected to a metallic case by the earth ring and to a field effect type transistor by the reflection plate. CONSTITUTION:When IR ray is made incident to the sensor from the outside of a metallic case 27 through a window hole 26 and a window member 25, voltage is generated in a pyroelectric film 22. The IR ray transmitted through the film 22 is reflected by a reflection plate 21 and is made incident again to the film 22. The incident IR B1, C2 produce a ratio. The output of the film 22 is applied through the plate 21 to the gate of a field effect type transistor 17, and an earth circuit is grounded via an earth ring 23 to the case 27.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pyroelectric infrared sensor using a pyroelectric film.

As shown in FIG. 1, a conventional pyroelectric infrared sensor has a lead wire 2 drawn out from a circuit case 1 housing a circuit element, a field effect transistor 3 for impedance matching mounted on the circuit case 1, and a field effect transistor 3 for impedance matching mounted on the circuit case 1. A cylindrical support base 4 made of an insulating material, an insulating inner case 5 arranged around the outer periphery of the support base 4, a flat reflecting plate 6f placed on the support base 4, and a flat reflecting plate 6f placed on the supporting stand 4. A conductive spring 7 formed in a ring shape and a wave shape is disposed, and a pyroelectric film 10 whose peripheral portion is held by conductive rings 8 and 9 is disposed, and a pyroelectric film 10 is disposed on the conductive ring 9 and inside the insulating case. 5
A large-diameter conductive ring 11 is provided on top of the conductive ring 11, and a window portion 12 made of silicone or the like that allows infrared rays to pass through is placed on the conductive ring 11. It was made up of eight covers.

With this configuration, an electric signal passes through the conductive ring 8°, the conductive spring 71, and the reflective plate 6, enters the gate of the field effect transistor 3, passes through the ground circuit d, the conductive ring 9, and the conductive ring 11, and then reaches the metal case 14. In this way, the conventional pyroelectric infrared sensor uses a large number of conductive rings 8, 9, 11, conductive springs 7, etc., and each component is stacked on top of the other, and finally the metal case 14 is connected to the ground. Because the circuit case 1 and circuit case 1 are assembled firmly together, there are 19 disadvantages, such as misalignment of component parts, resulting in (2) ji connection failures, requiring time and effort to assemble, and being disadvantageous in terms of cost. /(,.

The present invention eliminates the following drawbacks of the conventional technology, and aims to provide a highly reliable pyroelectric infrared sensor without simplifying the configuration. It is.

In order to achieve the above object, the present invention II has a reflective plate having a dish shape with a central part protruding downward, and a peripheral part of the reflective plate and a grounding ring. The device is characterized in that it is configured such that it is connected to a metal ground and connected to a field effect transistor by a reflective plate.

Embodiments of the present invention will be described below with reference to FIG. 2.

15 is a stem whose outer periphery is made of metal and whose interior is filled with an insulator such as glass, and several terminals 16 are implanted in this stem 15; A field-effect transistor 17 for impedance matching is incorporated on the top 171. At the same time, a cylindrical support 18 made of an insulator such as synthetic '1811W is arranged around the field effect transistor 1. Two stepped portions 19 and 20 are provided on the two sides of this support stand 18,
A peripheral portion of a dish-shaped reflector plate 21 made of a shiny metal such as nickel silver and having a central portion protruding downward is disposed in the lower step portion 19, and a field-effect transistor 17 is disposed at the center of the reflector plate 21. gate is connected.

Further, a peripheral portion of a pyroelectric film 220 such as polyvinylidene fluoride is arranged on the upper step portion 2o of the support base 18,
This pyroelectric film 22 contacts the peripheral edge of the above-mentioned reflecting plate 21 and is electrically conductive thereto.

An earth ring 23 made of phosphor bronze or the like is arranged on the upper surface of the pyroelectric film 22 and the upper surface of the support base 18.

On the upper surface of this earth ring 23, a window portion A26 made of silicon or the like that allows infrared rays to pass through is arranged through an elastic ring 24 made of rubber or the like. This metal case 27 is connected to the steno, 16. This metal case 27v1 is made of nickel-plated iron or the like, -I: Nl' peripheral edge of the near sling 23 iJ: 11 that is in contact with and electrically connected to the inner circumference of the metal case 27. With this configuration, when infrared rays enter from the outside of the metal case 27 through the window hole 26 and the window portion 4'A26, a voltage is generated in the pyroelectric film 22. Note that the infrared rays that pass through the pyroelectric film 22 are reflected by the reflector 21 and enter the pyroelectric film 22 again to output an output according to the incident infrared rays. film 22
The output Q1 is applied to the gate of the field effect transistor 17 through the reflection plate 21, and the ground circuit is connected to the ground ring 2.
The case is grounded to the metal case 27 via 3.

Since the pyroelectric field/AHA sensor 11 of the present invention is configured as described above, electrical connections are made between the pyroelectric film and the field effect transistor using a reflector plate, and from the pyroelectric film to the metal case using only the ground ring. Squid, the conduction? cJ6, 211 oz. 9. □1 It not only has excellent flexibility but also greatly increases the reliability of its conduction.Furthermore, since it forms a pyroelectric filmed space using only the reflector, it accumulates heat from incident infrared rays and becomes a focal point. It has the advantage of being able to increase the reactivity of conductive films, and is of great industrial value.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a conventional pyroelectric infrared sensor;
The figure is a sectional view showing an embodiment of the pyroelectric infrared sensor of the present invention. 15...Stem, 16...Terminal, 17
・・・・・・Field effect transistor, 18・・・・・・
・Support stand, 19.20...Stepped part, 21...
・・Reflector, 22・・Buddha・φ・Pyroelectric film, 23・
... Earth ring, 24 ... Elastic ring, 26 ... Wind member, 26 ... Window hole, 27 ... Metal case.

Claims (1)

[Claims] A field-effect transistor is placed on a stem having a terminal, and a cylindrical support is placed on the support, and a reflective plate whose center part protrudes downward and a pyroelectric film are brought into contact with the pyroelectric film at the periphery. and connecting the center of the reflector to the gate of the field effect transistor,
A pyroelectric infrared sensor is obtained by covering the pyroelectric film with a metal case in which a window member that transmits infrared rays is attached to the window hole, and electrically connecting the ground ring to the metal case.