JP6354465B2 - Infrared sensor and method for adjusting sensitivity of infrared sensor - Google Patents

Description

  The present invention relates to an infrared sensor that detects infrared rays from a measurement object and measures the temperature of the measurement object, and a sensitivity adjustment method for the infrared sensor.

Conventionally, an infrared sensor is used as a temperature sensor that measures the temperature of an object to be measured by detecting infrared rays radiated from the object to be measured in a non-contact manner.
For example, in Patent Document 1, a resin film installed on a holder, a thermal element for detecting infrared rays that is provided on the resin film and detects infrared rays through a light guide portion of the holder, and provided in a light-shielded state on the resin film. An infrared temperature sensor including a temperature-compensating thermosensitive element for detecting the temperature of the holder is proposed.

  In this infrared temperature sensor, a shielding part for reducing the amount of infrared rays incident on the light guide part is provided in the light guide part, and a variable projecting part such as a screw is applied as the shielding part to increase the projecting distance into the light guide part. By varying the amount of incident infrared rays, the variation in detection temperature of each infrared temperature sensor is corrected.

JP 2002-156284 A

The following problems remain in the conventional technology.
In the technique of Patent Document 1, a variable protrusion such as a screw is incorporated in a case to correct a sensor error caused by manufacturing variations. However, the structure of the case becomes complicated because the variable protrusion is incorporated, and the component There was a disadvantage that the cost would increase.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide an infrared sensor and a sensitivity adjustment method for the infrared sensor that are inexpensive and can correct variations in detection sensitivity.

  The present invention employs the following configuration in order to solve the above problems. That is, the infrared sensor according to the first invention includes an insulating film, a first thermal element and a second thermal element provided on one surface of the insulating film so as to be separated from each other, and the insulating film. A conductive first wiring film connected to the first thermal element and a conductive second wiring film connected to the second thermal element, and at least the second An infrared reflection film provided on the other surface of the insulating film so as to face the thermal element, and the infrared reflection film is formed on the other surface of the insulating film facing the first thermal element. It also has a plurality of unit reflection film portions that are divided and patterned into regions.

  In this infrared sensor, since the infrared reflective film has a plurality of unit reflective film portions that are also divided and patterned in the region of the other surface of the insulating film that faces the first thermal element. The detection sensitivity can be adjusted by painting the unit reflection film portion with a paint having a high infrared emissivity and adjusting the amount of infrared rays on the infrared absorption region side. Therefore, it is not necessary to complicate the structure of the case or the case, and the sensitivity can be adjusted at a low cost with a simple configuration.

The infrared sensor according to a second aspect of the present invention is the infrared sensor according to the first aspect, wherein the plurality of unit reflection film portions avoid the space between the first thermal element and the second thermal element. It is arranged on the outside just above.
That is, when a plurality of unit reflection film portions are arranged between the first heat sensitive element and the second heat sensitive element, the infrared reflection film on the infrared reflection region side is increased and the balance of thermal resistance is lost. However, in the infrared sensor of the present invention, the plurality of unit reflection film portions are arranged on the outer side immediately above the first thermal element that avoids the space between the first thermal element and the second thermal element. Therefore, the balance of thermal resistance is difficult to break. That is, the response characteristic can be maintained without impairing heat transferability between the absorption region and the reflection region.

An infrared sensor according to a third invention is the infrared sensor according to the first or second invention, wherein the plurality of unit reflection film portions are formed in a square pad shape and are arranged in a plurality of rows at intervals from each other. It is characterized by.
That is, in this infrared sensor, since the plurality of unit reflection film portions are formed in a square pad shape and arranged in a plurality of rows at intervals from each other, the unit reflection film portions can be easily selected and painted. The reproducibility of sensitivity adjustment due to increases.

An infrared sensor according to a fourth invention is characterized in that, in any one of the first to third inventions, the plurality of unit reflection film portions are composed of at least two different areas.
That is, in this infrared sensor, since the plurality of unit reflection film portions are configured with at least two different areas, when the sensitivity adjustment is performed in different increments, the area corresponding to the magnitude of the sensitivity adjustment is reduced. The unit reflection film portion can be filled, and adjustment with higher accuracy becomes possible.

A sensitivity adjustment method for an infrared sensor according to a fifth invention is the sensitivity adjustment method for an infrared sensor according to any one of the first to fourth inventions, and any one or more of the plurality of unit reflection film portions. Further, a paint having an infrared emissivity higher than that of the unit reflection film portion is applied.
That is, in the sensitivity adjustment method of the infrared sensor, an infrared ray emissivity is higher than that of the unit reflection film part on any one or more of the plurality of unit reflection film parts. The amount of infrared rays on the absorption region side can be adjusted, and the detection sensitivity of the infrared sensor can be easily adjusted.

The present invention has the following effects.
That is, according to the infrared sensor and the sensitivity adjustment method of the infrared sensor according to the present invention, the infrared reflective film is also divided and patterned into the region of the other surface of the insulating film facing the first thermal element. Since it has multiple unit reflection film parts, the detection sensitivity is adjusted by painting the top of the multiple unit reflection film parts with paint with high infrared emissivity and adjusting the amount of infrared light on the infrared absorption area side. can do. Therefore, variations in detection sensitivity can be corrected, and the detection accuracy of the infrared sensor can be improved. In addition, the detection sensitivity can be adjusted not only after the infrared sensor is incorporated into the housing or the case but also before the incorporation.

It is the top view before (a) and after adjustment (b) which shows 1st Embodiment of the infrared sensor which concerns on this invention, and the sensitivity adjustment method of an infrared sensor. In 1st Embodiment, it is a perspective view which shows an infrared sensor. In 1st Embodiment, it is sectional drawing which shows an infrared sensor. In 1st Embodiment, it is a bottom view which shows the insulating film before a thermal element is adhere | attached. In 1st Embodiment, it is a perspective view which shows the infrared sensor except a housing | casing. It is a top view before adjustment which shows 2nd Embodiment of the sensitivity adjustment method of the infrared sensor which concerns on this invention, and an infrared sensor.

  Hereinafter, a first embodiment of an infrared sensor and an infrared sensor sensitivity adjustment method according to the present invention will be described with reference to FIGS. 1 to 5. In each drawing used for the following description, the scale is appropriately changed in order to make each member recognizable or easily recognizable.

  As shown in FIGS. 1 to 3, the infrared sensor 1 of the present embodiment includes an insulating film 2, a first thermal element 3 </ b> A and a first thermal element 3 </ b> A provided on one surface of the insulating film 2 so as to be separated from each other. 2 thermal element 3B and conductive first wiring film 4A formed on one surface of insulating film 2 and connected to first thermal element 3A and conductive element connected to second thermal element 3B The second wiring film 4B, the infrared reflecting film 6 provided on the other surface of the insulating film 2 so as to face at least the second heat sensitive element 3B, and fixed to one surface of the insulating film 2 A housing 7 is provided that supports the insulating film 2 and accommodates the first heat sensitive element 3A and the second heat sensitive element 3B in an internal accommodating portion 7a.

The infrared reflection film 6 has a plurality of unit reflection film portions 6a that are also divided and patterned into a region (absorption region) on the other surface of the insulating film 2 facing the first thermal element 3A. Yes.
The plurality of unit reflection film portions 6a are arranged on the outer side directly above the first thermal element 3A, avoiding the space between the first thermal element 3A and the second thermal element 3B.
The plurality of unit reflection film portions 6a are formed in a square pad shape, and are arranged in a plurality of rows at intervals. In the present embodiment, two rows of five unit reflection film portions 6a each having a size of about 0.2 mm square are arranged in one row.

  As shown in FIG. 4, the first wiring film 4A is arranged up to the periphery of the first thermal element 3A and has a larger area than the second wiring film 4B. These first wiring films 4 </ b> A are provided with the first thermosensitive element 3 </ b> A at the center of a pair, and the outer shape of the pair is set to be substantially the same as the infrared reflecting film 6. That is, the area and shape of the first wiring film 4A are set so that the heat capacity is substantially equal to the portion of the insulating film 2 where the infrared reflective film 6 is formed.

Further, the first wiring film 4A and the infrared reflecting film 6 have a shape that covers the upper portion of the storage portion 7a in plan view. That is, when viewed from the upper side of the insulating film 2 (plan view), the first wiring film 4A and the infrared reflective film 6 that are paired and whose outer shapes are set to be substantially the same rectangular shape as the infrared reflective film 6; Thus, substantially the entire upper portion of the rectangular parallelepiped storage portion 7a is closed.
The pair of first wiring films 4A is connected to the first adhesive electrode 5A formed on the insulating film 2 at one end thereof and to the other end portion on the insulating film 2 respectively. The first terminal electrode 8 </ b> A formed on is connected.

Further, the pair of second wiring films 4B are formed in a linear shape, and one end portion thereof is connected to the second adhesive electrode 5B formed on the insulating film 2, and the other end portion. A second terminal electrode 8B formed on the insulating film 2 is connected to each other.
Note that the terminal electrodes 3a of the first heat sensitive element 3A and the second heat sensitive element 3B are bonded to the first adhesive electrode 5A and the second adhesive electrode 5B, respectively, with a conductive adhesive such as solder.

  The insulating film 2 is formed of a polyimide resin sheet, and the infrared reflection film 6, the unit reflection film portion 6a, the first wiring film 4A, and the second wiring film 4B are formed of copper foil. That is, these are the float electrodes of copper foil used as the infrared reflective film 6, the unit reflective film part 6a, the first wiring film 4A, and the second wiring film 4B on both surfaces of the polyimide substrate used as the insulating film 2. Is produced by a double-sided flexible substrate on which a pattern is formed.

  Further, as shown in FIG. 4, the infrared reflection film 6 is arranged in a substantially square shape immediately above the second heat sensitive element 3B and surrounds an absorption region directly above the first heat sensitive element 3A. It is formed in a frame shape. In this frame-like infrared reflective film 6, a plurality of unit reflective film portions 6a arranged in two rows are arranged. That is, the substantially rectangular portion of the infrared reflecting film 6 formed immediately above the second thermosensitive element 3B becomes an infrared reflecting region, and the region surrounded by the frame-like infrared reflecting film 6 absorbs infrared rays. It becomes an area. The infrared reflective film 6 including these unit reflective film portions 6a is composed of a copper foil and a gold plating film laminated on the copper foil.

  The infrared reflecting film 6 is formed by applying a gold plating film on a copper foil. In addition to the gold plating film, for example, a mirror-deposited aluminum vapor deposition film or an aluminum foil may be used. The infrared reflective film 6 disposed immediately above the second heat sensitive element 3B is formed so as to cover it with a size larger than that of the second heat sensitive element 3B.

  The first thermal element 3A and the second thermal element 3B are chip thermistors in which terminal electrodes 3a are formed at both ends as shown in FIG. As this thermistor, there are thermistors of NTC type, PTC type, CTR type and the like. In this embodiment, for example, NTC type thermistors are employed as the first thermal element 3A and the second thermal element 3B. This thermistor is formed of a thermistor material such as a Mn—Co—Cu-based material or a Mn—Co—Fe-based material.

In particular, in the present embodiment, the first thermal element 3A and the second thermal element 3B are formed of a ceramic sintered body containing a metal oxide of Mn, Co, and Fe, that is, an Mn—Co—Fe-based material. Thermistor element is used. Furthermore, this ceramic sintered body preferably has a crystal structure having a cubic spinel phase as a main phase. In particular, as a ceramic sintered body, a single-phase crystal structure composed of a cubic spinel phase is most desirable.
The first thermal element 3A and the second thermal element 3B are mounted on the insulating film 2 by bonding the terminal electrodes 3a onto the corresponding first adhesive electrode 5A or the second adhesive electrode 5B. Has been.

The casing 7 is made of a resin such as PPS (polyphenylene sulfide resin), and houses the first thermal element 3A and the second thermal element 3B, and has an air conductivity lower than that of the insulating film 2. A storage portion 7a which is a space covered with is provided inside.
A bottom surface reflecting film 9 that reflects infrared rays is formed on the bottom surface of the housing 7 facing the insulating film 2. As the bottom reflective film 9, a film similar to the infrared reflective film 6 can be adopted.

  As shown in FIGS. 2 and 3, the housing 7 is provided on the side surface, and the upper end is connected to the second terminal electrode 8B of the first wiring film 4A or the second wiring film 4B and extends to the bottom. A plurality of side electrode portions 10a are provided, and a plurality of mounting external terminals 10b are provided that are connected to the lower end of the side electrode portion 10a at the lower portion of the side surface and are connected to an external circuit board. That is, the infrared sensor 1 of the present embodiment is a surface mount type. The side electrode part 10a and the mounting external terminal 10b are made of, for example, a tin-plated copper alloy.

  When the detection sensitivity is adjusted in the infrared sensor 1 of the present embodiment, the paint Ink having an infrared emissivity higher than that of the unit reflection film part 6a is provided on any one or more of the plurality of unit reflection film parts 6a. Apply. For example, as shown in FIG. 1A, among the unit reflection film portions 6a arranged in two rows, on the two unit reflection film portions 6a arranged at both ends of the left column in the drawing, As shown in 1 (b), paint Ink is applied and filled. As a result, the infrared reflectance in the entire absorption region is reduced by the amount of the unit reflection film portion 6a that is filled.

  As the paint Ink, for example, ink made of synthetic resin, pigment, dimethyl ether, or the like can be used. As a method for applying the coating material Ink, it is preferable to apply the ink by an ink jet method using ink for an ink jet printer that can be printed on a metal surface. In this case, the coating Ink can be printed accurately and at high speed on the minute unit reflective film portion 6a, and the mass productivity is excellent.

  Thus, in the infrared sensor 1 of the present embodiment, the infrared reflection film 6 is divided into a plurality of unit reflection patterns that are also divided into the region of the other surface of the insulating film 2 facing the first thermal element 3A. Since it has the film part 6a, the detection sensitivity is adjusted by painting the top of the plurality of unit reflection film parts 6a with a paint Ink having a high infrared emissivity and adjusting the amount of infrared light on the infrared absorption region side. Can do. Therefore, it is not necessary to complicate the structure of the case or the case, and the sensitivity can be adjusted at a low cost with a simple configuration.

Further, since the plurality of unit reflection film portions 6a are arranged on the outer side immediately above the first thermal element 3A avoiding the space between the first thermal element 3A and the second thermal element 3B, Balance is difficult to break. That is, the response characteristic can be maintained without impairing heat transferability between the absorption region and the reflection region.
Furthermore, since the plurality of unit reflection film portions 6a are formed in a square pad shape and arranged in a plurality of rows at intervals, it is easy to select and paint the unit reflection film portions 6a and adjust sensitivity by filling. The reproducibility of becomes higher.

  As described above, in the sensitivity adjustment method of the infrared sensor 1, the paint Ink having an infrared emissivity higher than that of the unit reflection film part 6a is applied on any one or more of the plurality of unit reflection film parts 6a. The amount of infrared rays on the infrared absorption region side can be adjusted, and the detection sensitivity of the infrared sensor 1 can be easily adjusted. Therefore, variations in detection sensitivity can be corrected, and the detection accuracy of the infrared sensor 1 can be improved. The detection sensitivity can be adjusted not only after the insulating film 2 is fixed to the housing 7 but also before the insulating film 2 is fixed to the housing 7.

  Next, a second embodiment of the infrared sensor and the sensitivity adjustment method of the infrared sensor according to the present invention will be described below with reference to FIG. Note that, in the following description of the embodiment, the same components described in the above embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  The difference between the second embodiment and the first embodiment is that in the first embodiment, the plurality of unit reflection film portions 6a are all of the same area, whereas in the infrared sensor of the second embodiment, As shown in FIG. 6, the plurality of unit reflection film portions 26a, 26b, and 26c are configured with at least two different areas.

That is, in the second embodiment, for example, the unit reflection film part 26a having the largest area, the unit reflection film part 26b having the next largest area, and the unit reflection film part 26c having the smallest area are large. A plurality of unit reflection film portions are formed by three kinds of areas of small and medium.
When the sensitivity adjustment is performed in the second embodiment, for example, when a large sensitivity adjustment is desired, the unit reflection film portion 26a having a large area is filled, and when a small sensitivity adjustment is desired, the unit reflection film portion 26c having a small area is painted. Crush.

  As described above, in the second embodiment, since the plurality of unit reflection film portions 26a, 26b, and 26c are configured with at least two different areas, the sensitivity adjustment is performed when the sensitivity adjustment is performed in different increments. The unit reflection film portion having an area corresponding to the size can be filled, and adjustment with higher accuracy becomes possible.

  The technical scope of the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention.

  For example, in the above embodiment, the first heat-sensitive element detects heat conducted from the insulating film that directly absorbs infrared rays. However, the first heat-sensitive element directly absorbs infrared rays on the insulating film immediately above the first heat-sensitive element. A film may be formed. In this case, the infrared absorption effect in the first thermal element is further improved, and a better temperature difference between the first thermal element and the second thermal element can be obtained. That is, the infrared absorption film absorbs infrared rays due to radiation from the object to be measured, and the temperature of the first thermosensitive element immediately below is obtained by heat conduction through the insulating film from the infrared absorption film that absorbs infrared rays and generates heat. May be changed. The unit reflection film portion is formed on the infrared absorption film.

Moreover, although the 1st thermal element and the 2nd thermal element of a chip | tip thermistor are employ | adopted, you may employ | adopt the 1st thermal element and the 2nd thermal element which were formed with the thin film thermistor.
As the thermal element, a thin film thermistor or a chip thermistor is used as described above, but a pyroelectric element or the like can be used in addition to the thermistor.

  Moreover, in the housing | casing of the said embodiment, although the one storage part which accommodates a 1st thermosensitive element and a 2nd thermosensitive element is provided in the inside, a partition wall is provided inside a housing | casing, and a 1st thermosensitive element is provided. In addition, a pair of storage portions that individually store the second thermosensitive elements may be provided. Moreover, although the inside of the accommodating part is made into the space by the air whose heat conductivity is lower than an insulating film, you may fill with the foamed resin whose heat conductivity is lower than an insulating film.

  Furthermore, in the above embodiment, the area of the first wiring film is increased and the second wiring film is formed in a linear shape. However, the area of the second wiring film may be set to be somewhat large. In this case, since the heat capacity on the infrared reflective film side changes, it is necessary to consider changes in the ambient temperature, and each wiring film and infrared reflective film have the same heat capacity as much as possible on the reflective side and the absorption side. It is necessary to set the shape and area.

  DESCRIPTION OF SYMBOLS 1 ... Infrared sensor, 2 ... Insulating film, 3A ... 1st thermal element, 3B ... 2nd thermal element, 4A ... 1st wiring film, 4B ... 2nd wiring film, 6 ... Infrared reflective film, 6a , 26a, 26b, 26c... Unit reflection film part, 7... Casing, 7 a.

Claims (5)

An insulating film;
A first thermal element and a second thermal element provided on one surface of the insulating film so as to be spaced apart from each other;
A conductive first wiring film formed on one surface of the insulating film and connected to the first thermal element; and a conductive second wiring film connected to the second thermal element;
An infrared reflective film provided on the other surface of the insulating film so as to face at least the second thermal element;
The infrared reflection film has a plurality of unit reflection film parts that are divided and patterned into a region of the other surface of the insulating film facing the first thermosensitive element ;
The infrared sensor characterized in that the plurality of unit reflection film portions are arranged on the outer side directly above the first thermal element, avoiding the space between the first thermal element and the second thermal element. . The infrared sensor according to claim 1 ,
2. The infrared sensor according to claim 1, wherein the plurality of unit reflection film portions are formed in a square pad shape and are arranged in a plurality of rows at intervals. The infrared sensor according to claim 1 or 2 ,
The infrared sensor, wherein the plurality of unit reflection film portions are formed of at least two different areas. An insulating film, a first heat sensitive element and a second heat sensitive element provided on one surface of the insulating film, and the first heat sensitive element formed on one surface of the insulating film. A conductive first wiring film connected to the element, a conductive second wiring film connected to the second thermal element, and at least the second thermal element facing the second thermal element; An infrared reflection film provided on the other surface, and the infrared reflection film is also divided into a region of the other surface of the insulating film facing the first heat sensitive element, and a plurality of patterns are formed. A method for adjusting the sensitivity of an infrared sensor having a unit reflection film part ,
A method of adjusting the sensitivity of an infrared sensor, wherein a paint having an infrared emissivity higher than that of the unit reflection film part is applied on any one or more of the plurality of unit reflection film parts. An insulating film;
  A first thermal element and a second thermal element provided on one surface of the insulating film so as to be spaced apart from each other;
  A conductive first wiring film formed on one surface of the insulating film and connected to the first thermal element; and a conductive second wiring film connected to the second thermal element;
  An infrared reflective film provided on the other surface of the insulating film so as to face at least the second thermal element;
  The infrared reflection film has a plurality of unit reflection film parts that are divided and patterned into a region of the other surface of the insulating film facing the first thermosensitive element;
  An infrared sensor, wherein a paint having an infrared emissivity higher than that of the unit reflection film part is applied on any one or more of the plurality of unit reflection film parts.

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