JP3064442U - Pyroelectric infrared detector - Google Patents

Abstract

(57) [Summary] (Modified) [PROBLEMS] A conventional one-output four-element type pyroelectric infrared detector etches a single-plate pyroelectric body to thermally isolate between light-receiving elements. In such a case, the outer periphery of the light receiving element is cut out or dicing is performed to support two sides of the pyroelectric body divided for each light receiving element. However, complete thermal isolation is not possible by etching, and it is impossible to obtain a uniform output in all detection directions by supporting two sides of the pyroelectric body divided by dicing. Therefore, a one-output four-element type pyroelectric infrared detector having excellent thermal isolation between elements and no directionality of detection capability is provided. In a pyroelectric infrared detector of a one-output four-element type, a pyroelectric body 3 on which a light receiving element 4 is formed is divided for each element, and each pyroelectric body is provided with a distance. Each diagonal is supported at two vertices.

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 The present invention relates to a pyroelectric infrared detector used for detecting a human body and the like.

[0002]

[Prior art]

 The one-output, four-element pyroelectric detector mounted on the ceiling-mounted human body detection device is intended to detect micromotion, and increases the sensitivity by thermally isolating the light receiving elements and the thermal factors between each element. As shown in Fig. 2, a method of forming a cutout in the outer periphery of the light receiving element by etching or otherwise processing a single-plate pyroelectric body, or dicing each light receiving element The pyroelectric body was divided into two parts, and two sides of each pyroelectric body were supported on a support.

[0003]

[Problems to be solved by the invention]

 However, the method of forming cutouts in the outer periphery of the light receiving element by etching, as represented in FIG. 2, requires a bridge portion to be left on a part of the outer periphery of the light receiving element, so that complete thermal isolation is not possible. In addition, there is a problem that when infrared rays emitted from the detection target enter one light receiving element, crosstalk between the elements occurs due to heat propagation on the pyroelectric body. In addition, there was also a problem that uniform output could not be obtained when moving heat sources in all detection directions due to heat diffusion at the bridge. As a method of completely performing thermal isolation and eliminating crosstalk, there is a method of dividing each light receiving element by dicing and disposing each pyroelectric body on a support table as shown in FIG. However, in the prior art, since the two sides of each pyroelectric body were supported on a support base, the support when the pyroelectric body was warmed by the incidence of infrared rays emitted from the moving object to be detected. Since the degree of escape of heat transmitted through the table differs depending on the direction to be detected, there is a problem that a uniform output cannot be obtained in moving the heat source in all directions, as in the case of etching.

[0004]

Means for Solving the Problems In order to solve the above-mentioned problems, a one-output four-element type pyroelectric infrared detector according to the present invention uses a pyroelectric body divided for each light receiving element. Are supported on the support at two vertices.

[0005]

[Embodiment of the invention]

 FIG. 1 shows an embodiment of the present invention. The present invention is based on the idea that a pyroelectric body with a light receiving element formed by a technique such as evaporation is combined with a field effect transistor (FET) for impedance conversion, an internal wiring board (details of wiring pattern are omitted), and a resistor in one package. Hermetic.

[0006]

【Example】

 Hereinafter, an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a diagram showing the internal structure of a one-output four-element type pyroelectric infrared detector according to the present invention. Electronic components such as an electrolytic effect transistor (FET) for impedance conversion are mounted on the internal wiring board on which the wiring pattern is formed, and a support base for mounting the divided pyroelectric elements is provided on the surface thereof. Is formed. Further, the pyroelectric body on which the light receiving element is formed by a technique such as vapor deposition is cut slightly larger than the light receiving element size by a method such as dicing, so that one pyroelectric body is formed on one pyroelectric body. Only the light receiving element is formed. The pyroelectric element is mounted on the above-mentioned support base at a distance from each other and in a form supported at two diagonal vertices of the pyroelectric element, and is fixed and electrically connected by a conductive adhesive or the like. Has been established. Heat sources in the respective detection target directions of the one-output four-element pyroelectric infrared detector according to the present embodiment and the one-output four-element pyroelectric infrared detector according to the prior art shown in FIGS. 2 and 3. Fig. 4 shows a radar chart showing the output when moving. According to the radar chart, the one-output four-element type pyroelectric infrared detector according to the present embodiment has a uniform degree of escape of heat transmitted through the support irrespective of the detection target direction. It can be seen that a uniform output was obtained during the movement. In order to obtain a uniform output during the movement of the heat source in all detection target directions, there is a method of supporting each pyroelectric element at the four vertices as shown in Fig. 5, but the escape of heat transmitted through the support becomes large. Since sufficient sensitivity could not be obtained, two-vertex diagonal support was the most ideal.

[0007]

[Effect of the invention]

 According to the pyroelectric infrared detector of the one-output four-element type according to the present invention, since the thermal isolation between the light receiving elements is completely achieved, it is possible to completely avoid the crosstalk and not depend on the detection target direction. It is possible to obtain a uniform signal output in all directions.

[Brief description of the drawings]

FIG. 1 shows an example of a pyroelectric infrared detector of one output and four elements type according to an embodiment of the present invention.

FIG. 2 shows an embodiment of a pyroelectric infrared detector of one output and four elements type according to the prior art.

FIG. 3 shows another embodiment of a pyroelectric infrared detector of one output and four elements type according to the prior art.

FIG. 4 shows output comparison data between a one-output four-element type pyroelectric infrared detector according to an embodiment of the present invention and a one-output four-element type pyroelectric infrared detector according to the related art.

FIG. 5 is an embodiment of a pyroelectric infrared detector of one output and four elements type similar to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Window part 2 CAN 3 Pyroelectric body 4 Light receiving element 5 Internal wiring board 6 Support stand 7 Header

Claims (1)

[Utility model registration claims] 1. A one-output four-element type pyroelectric infrared detector mainly mounted on a ceiling-mounted type human body detection device that detects infrared rays, and a diagonal of each pyroelectric body divided for each light receiving element. A pyroelectric infrared detector characterized by supporting a pyroelectric body at two vertices.