JP2011095143A - Infrared sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact infrared sensor which can perform temperature correction with high accuracy at high speed. <P>SOLUTION: The infrared sensor includes a temperature sensor element, a quantum-type infrared sensor element that receives the external infrared ray from outside, a resin package encapsulating the infrared sensor element and the temperature sensor element, and an opening provided on the resin package to guide the infrared ray to a light receiving surface of the infrared sensor element. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an infrared sensor, and more specifically, an infrared sensor that detects infrared rays to measure temperature, detect people / things, detect gas concentration, etc. The present invention relates to an infrared sensor.

  In general, an infrared sensor can detect infrared rays and measure the temperature of an object in a non-contact manner. Infrared sensors are used in various applications such as human body detection, non-contact temperature measurement, and atmospheric gas concentration measurement. As a temperature measurement technique using a conventional infrared sensor, Patent Document 1 and the like are known. In order to correct the direct influence from the visual field while making the structure that makes the temperature of the metal part that becomes the light guide tube less affected by the outside world by combining resin and metal well in the visual field of the infrared sensor A highly accurate temperature sensor is realized by providing a correction thermometer in the visual field. In addition, as in Patent Document 2 and Patent Document 3, a method is known in which the temperature of the infrared sensor is reduced as much as possible by dynamically controlling the temperature of the package. Further, a method of correcting the influence of the light guide tube using a plurality of thermistors as in Patent Document 4 is known.

  In general, in order to realize a highly accurate thermometer and human sensor, an infrared sensor element such as a pyroelectric sensor or a thermopile is placed in a CAN package, and its periphery is covered with a metal block or the like to further increase thermal conductivity. Thus, it is known that the structure becomes relatively large.

Japanese Patent Laid-Open No. 08-191800 JP-A-11-155819 Japanese Patent No. 3346583 JP 2007-248201 A

  As described above, high-accuracy thermometers and human sensors are often used in which an infrared sensor element such as a pyroelectric sensor or a thermopile is incorporated in a CAN package having a large heat capacity. These peripheral parts must be equipped with external size components that limit the angle of infrared rays incident on the light receiving surface of the infrared sensor and have a large heat capacity, and external parts such as a heat sink. It was difficult to do.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an infrared sensor that is used for non-contact thermometer applications, human sensor applications, gas sensor applications, and the like, and is small, capable of temperature compensation with high speed and high accuracy.

  In order to solve such a problem, the infrared sensor according to claim 1 includes a temperature sensor element, a quantum infrared sensor element that receives infrared rays from the outside, the infrared sensor element, and the temperature sensor element. And an opening provided in the resin package so as to guide infrared rays to a light receiving surface of the infrared sensor element.

  An infrared sensor according to a second aspect is the infrared sensor according to the first aspect, wherein the temperature sensor element is disposed in contact with the infrared sensor element.

  The infrared sensor according to claim 3 is the infrared sensor according to claim 1 or 2, wherein a side surface of the opening is covered with a metal frame thermally coupled to the infrared sensor element. It is characterized by.

  The infrared sensor according to claim 4 is the infrared sensor according to claim 1 or 2, wherein a resin layer thermally coupled to the infrared sensor element is provided so as to surround a side surface of the opening portion, The resin layer has a higher thermal conductivity than the resin of the resin package around the resin layer.

  An infrared sensor according to a fifth aspect is the infrared sensor according to any one of the first to fourth aspects, wherein a depth of the opening portion of the resin package is 5 mm or less.

  The infrared sensor according to claim 6 is the infrared sensor according to any one of claims 1 to 5, wherein the infrared ray sensor is provided at any location on a surface other than the surface facing the surface having the opening portion in the resin package. The infrared sensor element and the temperature sensor element are provided with a plurality of notches so as not to be exposed to the outside.

  The infrared sensor according to the present invention does not need to be fitted with a field-of-view limiter having a large size and a large heat capacity, and a heat sink, so that the entire infrared sensor can be miniaturized. Therefore, a very small non-contact thermometer can be configured only by the infrared sensor and the post-processing signal processing system according to the present invention without preparing a special optical system. Therefore, a non-contact thermometer can be easily incorporated in a PDA terminal, a mobile phone, a wristwatch, a small electronic device, and the like. Furthermore, since the infrared sensor to be used is not a thermal infrared sensor such as a thermopile or pyroelectric sensor, but a quantum infrared sensor, the sensor itself has a high responsiveness and requires a CAN package with a large heat capacity. In this case, since the temperature and change of the infrared sensor itself are fast, the temperature between the infrared sensor and the package is good and temperature correction can be performed at high speed and with high accuracy.

  The infrared sensor according to the present invention provides a heat conduction between the quantum infrared sensor element and the resin package by providing a metal frame thermally coupled to the quantum infrared sensor element so as to cover the side surface of the opening. The temperature can be improved, and the temperature of the quantum infrared sensor element and the opening portion can be well tracked, so that temperature correction can be performed at high speed and with high accuracy.

  The infrared sensor according to the present invention is provided with a resin layer thermally coupled to the quantum infrared sensor element so as to surround the side surface of the opening, and the resin layer has a higher thermal conductivity than the resin of the surrounding resin package. By adopting such a configuration, it is possible to configure an infrared sensor that is less susceptible to external influences.

  The infrared sensor according to the present invention increases the thermal conductivity between the quantum infrared sensor element and the resin package by setting the depth of the opening portion of the resin package to 5 mm or less, and the quantum infrared sensor element and the resin package. And temperature correction can be performed at high speed and with high accuracy.

  In the infrared sensor according to the present invention, by providing a notch portion on the surface of the resin package and further increasing the contact surface with the outside air, the temperature of the infrared sensor element itself and the resin package portion are always the same temperature. As a result, the necessary temperature correction of the infrared sensor element can be performed quickly and accurately with only the temperature sensor element incorporated in the resin package.

It is a perspective view of the infrared sensor which concerns on this invention. It is sectional drawing of the infrared sensor which concerns on this invention. It is sectional drawing of the infrared sensor which concerns on Example 1 of this invention. 1 is a cross-sectional view of a miniaturized exemplary infrared sensor according to the present invention. It is sectional drawing of the infrared sensor which concerns on Example 2 of this invention. It is sectional drawing of the infrared sensor which concerns on Example 3 of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a perspective view of an infrared sensor according to the present invention. FIG. 2 is a cross-sectional view of an infrared sensor according to the present invention. As shown in FIGS. 1 and 2, the infrared sensor according to the present invention includes a resin package 1, and a quantum infrared sensor element 4 and a temperature sensor element 5 encased in the resin package 1. The resin package 1 is provided with an opening 2.

  The quantum infrared sensor element 4 and the temperature sensor element 5 are embedded in a thin resin package 1. The temperature sensor element 5 is disposed so as to be close to the quantum infrared sensor element 4. The opening 2 is provided by cutting through the resin package 1 on the light receiving surface 3 of the quantum infrared sensor element 4. The opening 2 serves as a light guide tube that guides light to the light receiving surface 3 of the quantum infrared sensor element 4 and a visual field limiter that narrows the visual field. The shape of the opening portion 2 is not particularly limited, and may be a square shape or a round shape. As will be described later, if necessary, a thin film optical filter may be attached to the resin package 1 so as to close the opening 2. There may be a plurality of the opening portions 2, and the depth of the opening portion 2 is several mm or less.

  An infrared sensor according to the present invention amplifies a signal of an infrared sensor element and adjusts a value uniquely determined from a temperature signal from the temperature sensor element, and a terminal for interface with the signal processing circuit (not shown) Prepared). Here, the signal processing circuit is a circuit that amplifies a signal from the infrared sensor element and performs a correction operation based on the temperature signal from the temperature sensor element. Thereby, temperature correction of the output of an infrared sensor element can be easily performed from the output of a temperature sensor element.

  In addition, the infrared sensor according to the present invention may have a configuration in which a terminal (not shown) for extracting signals from the quantum infrared sensor element 4 and the temperature sensor element 5 is provided in the resin package 1. That is, the signal processing circuit unit may be a separate package.

  Furthermore, as will be described later, the resin package 1 may have a structure in which a plurality of cutout portions are provided. Thereby, a surface area can be enlarged and the temperature of the resin package 1 and the temperature of the quantum type infrared sensor element 4 can be more effectively made the same.

  Furthermore, the height from the top of the opening 2 to the bottom of the resin package 1 can be 10 mm or less. Thereby, in addition to making it possible to reduce the heat capacity of the package, it is possible to ensure a sufficient field of view restriction and use it as a non-contact thermometer at a short distance.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 3 is a cross-sectional view of the infrared sensor according to Embodiment 1 of the present invention. As described above, the quantum infrared sensor element 4 and the temperature sensor element 5 are embedded in the thin resin package 1, and the opening portion 2 is provided in the resin package 1 so that the light receiving surface 3 of the quantum infrared sensor element 4 is exposed. . The opening part 2 serves as a visual field restriction part. The resin package 1 is a thin resin package 1 in which the opening 2 has a depth of 5 mm or less. By using such a thin resin package 1, the temperature difference between the resin package 1 on the side surface of the opening 2 and the quantum infrared sensor element 4 can be reduced. In FIG. 3, an optical filter that cuts a wavelength of 5 μm or less is attached to the resin package 1 so as to close the opening 2. As the quantum infrared sensor element 4, a room temperature operation type infrared sensor element using InSb was used.

  As shown in FIG. 3, a resin layer or metal frame 8 with high thermal conductivity that is thermally coupled to the quantum infrared sensor element 4 can be provided so as to surround the side surface of the opening portion 2. When a resin with high thermal conductivity or a resin with high thermal conductivity is used in the metal frame 8, the thermal conductivity of a normal PPS resin is about 0.4 W / m · K, but a metal filler is put into the resin. For example, a resin whose thermal conductivity is increased to several W / m · K is known and may be used.

  Furthermore, in recent years, resins having a thermal conductivity increased to about 25 W / m · K are also known. By providing such a resin with high thermal conductivity so as to surround the side surface of the opening portion 2, the temperature of the quantum infrared sensor element 4 and the temperature of the side surface of the opening portion 2 can be made substantially the same. Thereby, the thermal conductivity between the quantum infrared sensor element 4 and the resin package 1 can be increased, and temperature correction can be performed at high speed and with high accuracy. Similarly, when a metal frame is used in the resin layer or the metal frame 8 having a high thermal conductivity, the thermal conductivity between the quantum infrared sensor element 4 and the resin package 1 can be increased, and the quantum infrared sensor element 4 and the temperature of the opening portion can be tracked well, so that temperature correction can be performed at high speed and with high accuracy.

  In order to suppress the influence of heat conduction from the outside, a specific resin layer thermally coupled to the infrared sensor element is provided on the side surface of the opening 2, and the specific resin layer is a resin of the surrounding resin package 1. It is good also as a structure which becomes higher in heat conductivity. For example, a resin layer having high thermal conductivity may be provided so as to surround the side surface of the opening portion 2, and a resin having poor thermal conductivity can be used for the resin package 1 in other portions. Thereby, the infrared sensor which is hard to receive external influence can be comprised.

  Such a resin or metal frame 8 having a high thermal conductivity is obtained by first molding a part other than the resin or the metal frame 8 having a high thermal conductivity and then separately molding the resin or the metal frame 8 having a high thermal conductivity. It can be provided by inserting and affixing and incorporating a molded cylindrical thing later. Alternatively, the quantum infrared sensor element 4 and the molded part of the resin or metal frame 8 having high thermal conductivity may be bonded together first, and then integrally formed later.

  If the temperature of the quantum infrared sensor element 4 and the temperature of the resin package 1 on the side surface of the opening 2 are likely to be the same even though it is easily affected by the external temperature, the quantum infrared sensor element 4 can be measured by a high-speed temperature monitor. Temperature characteristics can be corrected at high speed.

  FIG. 4 shows an example in which the size of the resin package 1 is reduced as much as possible so that the temperature inside the resin package 1 and the temperature outside the resin package 1 become uniform. By reducing the thickness of the package resin 1 while leaving the field-of-view restriction part, the structure is such that the heat conduction efficiency from the package resin 1 to the quantum infrared sensor element 4 is increased. Although not shown, a lead wire and a pad are provided for signal extraction. In the structure as shown in FIG. 4, although it is easily affected by the external temperature, it is difficult for a temperature difference to occur between the quantum infrared sensor element 4 and the resin package 1 on the side surface of the opening 2. 4 can be corrected at high speed. Hereinafter, an example of a structure that is not easily affected by external temperature but hardly causes a temperature difference between the quantum infrared sensor element 4 and the resin package 1 on the side surface of the opening 2 will be described.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 5 is a cross-sectional view of an infrared sensor according to Embodiment 2 of the present invention. As described above, the quantum infrared sensor element 4 and the temperature sensor element 5 are embedded in the thin resin package 1, and the opening portion 2 is provided in the resin package 1 so that the light receiving surface 3 of the quantum infrared sensor element 4 is exposed. . The opening part 2 serves as a visual field restriction part. In the resin package 1, a cutout portion 7 is provided up to the vicinity of the quantum infrared sensor element 4 at any location on the surface where the opening portion 2 is provided. In this way, by providing a notch portion to further increase the contact surface with the outside, the structure is such that the temperature difference between the resin package 1 on the side surface of the opening portion 2 and the quantum infrared sensor element 4 is reduced. .

  Since it is necessary to follow the temperature of the resin package 1 on the side surface of the quantum infrared sensor element 4 and the opening portion 2 at a high speed, a resin or metal frame 8 having high thermal conductivity is provided on the side surface of the opening portion 2 to It may be thermally coupled to the sensor element 4. As the material of the resin package 1 other than the resin having a high thermal conductivity on the side surface of the opening 2 or the metal frame 8, a resin having a low thermal conductivity (ordinary resin) is used. Further, a resin or metal frame 8 having a partially high thermal conductivity may be provided around the cut portion 7. Preferably, a resin or metal frame 8 having high thermal conductivity is provided so as to connect the cut portion 7 and the quantum infrared sensor element 4. By providing the cutout portion 7, the temperature difference between the side surface of the opening portion 2 and the quantum infrared sensor element 4 is reduced, so that the temperature of the resin package 1 on the side surface of the opening portion 2 and the temperature of the quantum infrared sensor element 4 are reduced. The temperature correction can be performed at high speed and with high accuracy.

  If necessary, the optical filter 6 may be attached to the resin package 1 so as to close the opening 2.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 6 is a cross-sectional view of an infrared sensor according to Embodiment 3 of the present invention. As described above, the quantum infrared sensor element 4 and the temperature sensor element 5 are embedded in the thin resin package 1, and the opening portion 2 is provided in the resin package 1 so that the light receiving surface 3 of the quantum infrared sensor element 4 is exposed. The opening part 2 serves as a visual field restriction part. The cutout portion 7 is provided to the vicinity of the quantum infrared sensor element 4 in any place other than the surface of the resin package 1 where the opening portion 2 is provided and the surface of the resin package 1 opposite to the surface having the opening portion 2. Is provided. In this way, by providing a notch portion to further increase the contact surface with the outside, the structure is such that the temperature difference between the resin package 1 on the side surface of the opening portion 2 and the quantum infrared sensor element 4 is reduced. .

  As described in the second embodiment, a resin or metal frame 8 having high thermal conductivity may be provided on the side surface of the opening portion 2 and thermally coupled to the quantum infrared sensor element 4. As the material of the resin package 1 other than the resin having a high thermal conductivity on the side surface of the opening 2 or the metal frame 8, a resin having a low thermal conductivity (ordinary resin) is used. Further, a resin or metal frame 8 having a partially high thermal conductivity may be provided around the cut portion 7. Preferably, a resin or metal frame 8 having high thermal conductivity is provided so as to connect the cut portion 7 and the quantum infrared sensor element 4.

  Further, in combination with the second embodiment, the cutout portion 7 may be provided up to the vicinity of the quantum infrared sensor element 4 in any location other than the surface facing the surface having the opening portion 2 in the resin package 1. .

  By providing the cutout portion 7, the temperature difference between the resin package 1 on the side surface of the opening portion 2 and the quantum infrared sensor element 4 is reduced, so that the temperature on the side surface of the opening portion 2 and the temperature of the quantum infrared sensor element 4 are reduced. The temperature correction can be performed at high speed and with high accuracy.

  If necessary, the optical filter 6 may be attached to the resin package 1 so as to close the opening 2.

DESCRIPTION OF SYMBOLS 1 Resin package 2 Opening part 3 Light-receiving part 4 Quantum type infrared sensor element 5 Temperature sensor element 6 Optical filter 7 Notch part 8 Resin or metal frame with high heat conductivity

Claims (6)

A temperature sensor element;
A quantum-type infrared sensor element that receives infrared rays from the outside;
A resin package enclosing the infrared sensor element and the temperature sensor element;
An infrared sensor, comprising: an opening provided in the resin package so as to guide infrared light to a light receiving surface of the infrared sensor element.   The infrared sensor according to claim 1, wherein the temperature sensor element is disposed in contact with the infrared sensor element.   3. The infrared sensor according to claim 1, wherein a side surface of the opening portion is covered with a metal frame thermally coupled to the infrared sensor element.   A resin layer thermally coupled to the infrared sensor element is provided so as to surround a side surface of the opening portion, and the resin layer has higher thermal conductivity than a resin of the resin package around the resin layer. The infrared sensor according to claim 1 or 2, characterized in that   The infrared sensor according to claim 1, wherein a depth of the opening portion of the resin package is 5 mm or less.   In the resin package, a plurality of notched portions that are notched so as not to expose the infrared sensor element and the temperature sensor element to the outside are provided at any location other than the surface facing the surface having the opening portion. The infrared sensor according to claim 1, wherein the infrared sensor is provided.

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