JP2011112508A - Pyroelectric infrared detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that, since mounting members are small in number, and a heat capacity is small relative to a capacity in a pyroelectric infrared detector, when an abrupt temperature change is caused, a heat influence on a pyroelectric element is large, and a drift of an output signal has a limit to the temperature change. <P>SOLUTION: In order to enlarge the heat capacity, to reduce the heat influence on the pyroelectric element even if the abrupt temperature change is caused, and to suppress the drift of the output signal to the temperature change, a two-storied substrate structure having two built-in substrates in the pyroelectric infrared detector is adopted. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a pyroelectric infrared detector used for human body detection, lighting fixture control, and the like.

  As shown in FIG. 2, the conventional pyroelectric infrared detecting device receives infrared rays and generates charges by changing the amount of incident infrared rays, and an FET that converts charges generated from the pyroelectric elements into voltages. And an amplifier circuit composed of a resistor, an operational amplifier IC, a resistor and a capacitor packaged in a TO-5 type hermetically mounted on a header having lead terminals that are electrically connected to a metal can case having an infrared transmitting material. Is known as the prior art.

  In addition, the internal structure of a conventional pyroelectric infrared device includes a pyroelectric element in which a component such as a capacitor is mounted on one side, infrared rays are received on the other side, and electric charges are generated by a change in the amount of incident infrared rays. A lead terminal that is electrically connected to a substrate on which a conductive pattern is formed on the surface on which a support base that supports the substrate, an FET that converts electric charges generated from the pyroelectric element into a voltage, a resistor, and an operational amplifier IC are provided. It is mechanically installed on the upper surface of the header provided with the AU wire and is electrically connected to the header having a lead terminal for electrical connection with the substrate on which the conductor pattern or the like is formed on the surface. It becomes a structure.

Japanese Patent Application No. 2009-12648

  However, the conventional technology has fewer mounting members than the internal volume of the pyroelectric infrared detector, and the heat capacity is small. Therefore, when a sudden temperature change is applied, the pyroelectric element is greatly affected by heat, and the temperature change On the other hand, there is a problem that the output signal drifts.

  As shown in FIG. 2, a conventional TO-5 type package pyroelectric infrared detector has an internal structure in which components such as a capacitor are mounted on one side of one substrate, infrared rays are received on the other side, Mounted are a pyroelectric element that generates a charge by change, a support that supports the pyroelectric element, an FET that converts the charge generated by the pyroelectric element into a voltage, a resistor, and an operational amplifier IC. Compared with the conventional flat pack package pyroelectric infrared detector shown in FIG. 3, the output signal for the rapid temperature change of the conventional TO-5 package pyroelectric infrared detector shown in FIG. However, as shown in FIG. 4, the conventional TO-5 type package pyroelectric infrared detector shown in FIG. 2 has insufficient output signal stability against a sudden temperature change. Met.

  In order to solve the above-described problems, the present invention increases the heat capacity, reduces the thermal effect on the pyroelectric element even when a sudden temperature change is applied, and suppresses the drift of the output signal with respect to the temperature change. Therefore, it is characterized by a two-story substrate structure in which two substrates are built in the pyroelectric infrared detector.

  In the pyroelectric infrared detector, there are four capacitors for determining amplifier amplification gain frequency characteristics on one side of the substrate on which the internal wiring is formed, and an FET for converting the electric charge generated from the pyroelectric element into a voltage, and A resistor and a regulator circuit for stabilizing the voltage applied to the pyroelectric infrared detector, and an operational amplifier IC in which the amplifier circuit and the comparator circuit are housed in one package are mounted. A substrate formed and arranged with an internal wiring on which a pyroelectric element that receives an infrared ray on one side and generates an electric charge due to a change in the amount of incident infrared rays, a metal can case having an infrared transmitting material, and the substrate Hermetically sealing with a header with lead terminals that make electrical connections increases the volume of the mounting member inside the pyroelectric infrared detector, that is, pyroelectric red It is possible to increase the heat capacity of the line detector itself, by having a thermal fluctuation immunity from foreign, improved temperature drift performance.

  In addition, since the pyroelectric infrared detector of the present invention can be stored in a general TO-5 type package, the conventional pyroelectric infrared detector and the conventional pyroelectric infrared detector are not different from the conventional pyroelectric infrared detector. It is easy to replace.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded external view showing a pyroelectric infrared detection device according to a first embodiment of the present invention. It is a disassembled external view which shows the conventional TO-5 type package pyroelectric infrared detection apparatus. It is a disassembled external view which shows the conventional flat pack type package pyroelectric infrared detection apparatus. It is the graph which showed the output change at the time of the rapid ambient temperature change of the pyroelectric infrared detection apparatus of Example 1 of this invention and the conventional TO-5 type pyroelectric infrared detection apparatus.

Hereinafter, the present invention will be described in detail with reference to the drawings.
FIG. 1 is an exploded external view of a pyroelectric infrared detection apparatus according to the present invention. A metal can case 2 having a filter material 1 that allows infrared rays to enter and transmit, a pyroelectric element 3, a substrate 5a that supports the pyroelectric element, and a substrate 9a on which internal wiring is formed. A substrate 9b having an internal wiring on which an FET 8, a resistor 7, an operational amplifier IC6, a capacitor 10, and a support column 14 for electrically and mechanically fixing the substrate 9a are formed on the lower surface, and electrical connection with the substrate are formed. The header 11 provided with the lead terminal 12 has a hermetic seal in order to prevent environmental changes from outside and electromagnetic injuries.

  The substrate 9a is a thin substrate on which internal wiring (in FIG. 1, the wiring is complicated and omitted). The pyroelectric element 3 is formed with an electrode 4 for receiving infrared rays. A support base 5 for supporting the pyroelectric element 3 is provided on one side of the substrate 9a, and the pyroelectric element is provided on the support base 5. And is mechanically and electrically connected by a conductive adhesive or the like to receive infrared rays and take out the electric charges generated from the electrodes 4 that receive the infrared rays due to temperature changes.

  Further, the substrate 9b is provided with an impedance converting FET 8 and a resistor 7 for taking out electric charges as voltage conversion, and further, a regulator circuit for stabilizing the voltage applied to the pyroelectric infrared detecting device, impedance conversion is performed. The amplifier circuit is composed of an amplifier circuit 6 for amplifying the detected signal, and an operational amplifier IC6 having one comparator for determining detection / non-detection based on the signal output level extracted from the amplifier circuit, and the amplifier Four capacitors 10 for determining the frequency characteristics of the amplification gain are mounted.

  It should be noted that the impedance conversion FET8, the resistor 7, and the regulator circuit for stabilizing the voltage applied to the pyroelectric infrared detector for taking out the electric charges mounted on the substrate 9b and the substrate 9b as voltage conversion, impedance conversion An amplifier circuit for amplifying the detected signal, and an operational amplifier IC6 having a comparator for determining detection / non-detection based on the signal output level taken out from the amplifier circuit, and the amplifier circuit. The header 11 provided with the lead terminal 12 that electrically connects the four capacitors 10 for determining the frequency characteristics of the amplification gain and the substrate 9 b is electrically connected by the AU wire 13.

  The substrate 9b is provided with four support columns 14 for electrically and mechanically connecting and fixing the substrate 9a and the substrate 9b. The mounting position / height / equilibrium of the substrate 9a is maintained by mounting the substrate 9a on the upper portion of the four columns 14 for electrically and mechanically connecting and fixing the substrate 9a and the substrate 9b.

  Furthermore, among the four support posts 14 for electrically and mechanically connecting and fixing the substrate 9a and the substrate 9b, one is for impedance conversion for taking out the electric charge mounted on the substrate 9b as voltage conversion. The FET 8 and the resistor 7 are electrically connected to the pyroelectric element 3 mounted on the substrate 9a. The other three are grounded to improve shielding performance.

  The pyroelectric element 3, the support base 5 that supports the pyroelectric element, and the substrate 9 a on which the internal wiring is formed, and the lower surface of the substrate 9 a are applied to the FET 8, the resistor 7, and the pyroelectric infrared detector. A regulator circuit for stabilizing the voltage to be output, an amplifier circuit for amplifying the impedance-converted signal, and a comparator circuit for determining detection / non-detection based on the signal output level extracted from the amplifier circuit The substrate 9b on which the packaged operational amplifier IC6, the amplifier circuit, and the internal wiring on which the feedback capacitor 4 points 10 for determining the frequency characteristics of the amplifier circuit are mounted is formed between the metal can case 2 and the substrate 9b. Hermetically sealed to a header 11 having lead terminals 12 for electrical connection. Since these are housed in a general TO-5 type package, the design of optical lenses and mirrors for condensing infrared rays onto the light receiving electrode portion of the pyroelectric element, and the degree of freedom of use are greatly improved. The structure can be replaced with a product. In addition, this leads to a reduction in the size of the connection board that performs control and the like in a later circuit, and the pyroelectric infrared detection device itself can be reduced in cost and size. Furthermore, since the metal can case 2 and the header 11 having the lead terminal 12 that is electrically connected to the substrate 9 are connected to the ground of the pyroelectric infrared detector and are grounded. The structure is shielded against environmental changes from outside and electromagnetic injuries.

  FIG. 4 is a graph showing an output change when a sudden temperature change (about 4 ° C./min.) Is applied to the pyroelectric infrared detector of the present invention and the conventional pyroelectric infrared detector. In the conventional structure shown in FIG. 2, the internal structure of the pyroelectric infrared detector uses one substrate, whereas the pyroelectric infrared detector of the present invention shown in FIG. 1 uses two substrates. Therefore, the heat capacity is increased, and even when a sudden temperature change is applied, the thermal effect on the pyroelectric element can be reduced. Therefore, as shown in FIG. 4, it was confirmed that the drift of the output signal at the time of environmental temperature change was improved to 1/3.

  In the pyroelectric infrared detection apparatus of this embodiment, the infrared light receiving electrode 4 is a two-element dual type. However, an infrared detection circuit may be configured with various pyroelectric element sizes and light receiving electrode patterns. I can do it. Also, it is easy to provide an optical system for condensing infrared rays onto the light receiving electrode 4 of the pyroelectric element 3. These are configured without any particularity from conventional manufacturing techniques and assembly processes.

DESCRIPTION OF SYMBOLS 1 Filter material 2 Metal can case 3 Pyroelectric element 4 Electrode 5 Support stand 6 Operational amplifier IC
7 Resistance 8 FET
9 Substrate 10 Capacitor 11 Header 12 Lead terminal 13 AU wire 14 Post

Claims (1)

  By using a two-story substrate structure that contains two substrates with conductive patterns formed on the surface inside the pyroelectric infrared detector, a member that becomes a thermal absorber is placed, increasing the volume and heat capacity of the internal member. A pyroelectric infrared detecting device characterized in that it is stored in a TO-5 type package by a metal can case provided with an infrared transmitting material and a header.

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