JP3764565B2 - Thermal infrared detector - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a thermal infrared detector in which a thermosensitive element made of a thermopile is provided in a container made of a can and a stem.
[0002]
[Prior art]
One type of temperature measuring device that measures the temperature of an object in a non-contact manner is a thermal infrared detector in which a thermosensitive element made of a thermopile is provided in a container formed of a conductor. As shown in FIG. 4 , this thermal infrared detector includes a thermosensitive element 51 composed of a thermopile in which a plurality of thermocouples connected to two types of thermoelectric materials are connected in series. And a heat sink 57 supported in an insulated state by a positive lead pin 55 and a negative lead pin 56 supported via an insulating member 54 on the bottom surface portion 53a of the container 53, and a ground lead pin. 58 is provided in the container 53 of a conductor via solder 58a, and an infrared transmissive window 59 made of, for example, calcium fluoride is bonded to the container 53, and measurement is performed at the temperature junction of the temperature sensing element 51. It detects infrared rays radiated from the target object.
[0003]
[Problems to be solved by the invention]
However, in the conventional thermal type infrared detector configured as described above, the heat generated from the infrared transmissive window 59 by the incident infrared ray A cannot be released. 59 is detected together with infrared rays transmitted through 59 . Therefore, the output error is large and the visual field characteristics are poor.
[0004]
Further, since the infrared transmissive window 59 is made of calcium fluoride, the infrared transmissive window 59 and the container 53 are not electrically coupled, and the infrared conductive window 59 and the container 53 are electrically connected. Therefore, the shielding property against electromagnetics was poor, and it was easy to receive electrical noise. Therefore, a thermal infrared detector that operates stably over a long period of time cannot be obtained.
[0005]
The present invention has been made in consideration of the above-mentioned matters, and an object of the present invention is to efficiently release the heat generated from the infrared transmitting window by the incident infrared rays and to prevent the generation of electric noise. It is to provide a detector.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a can in which a first infrared transmitting window is coupled so as to be electrically conductive, and a lead pin for extracting a signal that is vertically insulated in an electrically insulated state. in a container comprising a stem having a in a state sandwiched between the upper and lower heat sinks, heat temperature sensitive element made of a thermopile is disposed the cold junction so as to bind to the two heat sink and thermal In the type infrared detector, the stem is made of copper, and the lower heat sink is made of copper and is formed into a bowl shape. is fixed to the upper surface of the stem by good heat conductive adhesive, and the upper heat sink is formed in a donut shape having a hole in its center portion made of copper, on the upper surface of the upper heat sink, A thermal conductive semiconductor is used as a base material, and only infrared light having a specific wavelength is transmitted through the first infrared transmitting window on both sides of the base material to reach the light receiving portion of the temperature sensing element. A second infrared transmissive window forming a wavelength selective multilayer film to be attached is fixed by a heat conductive adhesive in a state of covering a central hole of the upper heat sink, and at least the lower heat sink The lead pin is thermally coupled .
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, details of the present invention will be described with reference to the drawings.
[0008]
1 to 3 show a first embodiment of the present invention. First, in FIG. 1, reference numeral 1 denotes a cylindrical can 2 whose lower side is opened, and a plate-like shape that closes the lower opening side of the can 2. 2 and 3 are joined together by, for example, pressure welding (or welding), whereby the container 1 is sealed.
[0009]
The can 2 is, for example, a copper plate having a thickness of about 0.3 mm formed in a hat shape by press working, and its outer surface is mirror-finished or gloss-plated. In the central portion of the upper surface of the can 2, an infrared ray having a base material of a semiconductor having good thermal conductivity such as silicon or germanium is formed in an opening formed by cutting the portion into a rectangular shape of an appropriate size. A transmissive window (first infrared transmissive window) 4 is formed by soldering a with a coating film on both surfaces of the base material. And since the semiconductor is used as a base material, electrical conductivity is good. In addition, 5 is a collar part formed in the open lower end part of the can 2.
[0010]
The stem 3 is made of, for example, a copper plate having a thickness of about 1 mm. The stem 3 is provided with two lead pins 6 for extracting signals, and the penetrating portions 7 are glass-welded to electrically insulate the lead pins 6 and the stem 3 from each other. b is the glass welded part. Reference numeral 8 denotes a ground lead pin fixed to the lower surface of the stem 3 by an appropriate method.
[0011]
2 and 3, a thermosensitive element 9 is composed of a thermopile in which a plurality of thermocouples connected to two thermoelectric materials 10 and 11 are connected in series, for example, a thin insulating substrate made of polyethylene resin, for example. 12 is formed such that the cold junction 13 is located on the outside and the warm junction 14 is located on the inside. Reference numeral 15 denotes a signal extraction lead. A light receiving portion R of the temperature sensitive element 9 is formed in a region on the insulating substrate 12 including the temperature joining portion 14 of the temperature sensitive element 9. The light receiving portion R is made of, for example, a gold black or silver black vapor deposition film.
[0012]
Reference numeral 16 denotes a lower heat sink for holding the temperature sensing element 9. For example, a copper plate having a thickness of about 0.4 mm is formed into a bowl shape with a hole 16 a at the bottom by pressing, and this is turned down. It is placed in contact with the upper surface of the stem 3, and the lower end of the open side of the side portion 17 is fixed by an adhesive 18 having excellent thermal conductivity such as epoxy resin. Then, the temperature sensing element 9 formed on the insulating substrate 12 is placed on the upper flat portion 19 of the heat sink 16 so as to cover the hole 16a.
[0013]
Reference numeral 20 denotes a second infrared transmissive window that transmits infrared light transmitted through the first infrared transmissive window 4. A semiconductor having good thermal conductivity, such as silicon or germanium, is used as a base material. And a wavelength-selective multilayer film. Thereby, only the infrared light of a specific wavelength permeate | transmits the 2nd infrared transparent window 20. FIG. The second infrared transmissive window 20 is, for example, an 8 μm cut-on filter.
[0014]
Reference numeral 21 denotes an upper heat sink that holds the second infrared transmissive window 20 so as to face the first infrared transmissive window 4 and is made of copper and formed in a donut shape. The second infrared transmissive window 20 is fixed to the upper surface c of the upper heat sink 21 with a heat conductive adhesive (for example, epoxy resin).
[0015]
The temperature sensing element 9 is disposed so as to thermally couple the cold junction 13 to both the heat sinks 21 and 16 while being sandwiched between the two upper and lower heat sinks 21 and 16. That is, the temperature sensing element 9 is fixed so that the upper side thereof is in close contact with the bottom inner annular surface 21a of the upper heat sink 21 and is attached to the bottom outer annular surface 21b via the step m extending downward from the bottom inner annular surface 21a. The insulating substrate 12 is in close contact with the upper flat portion 19 of the heat sink 16.
[0016]
Further, the diameter D of the hole 22 of the upper heat sink 21 is set to 1.5 times or less of the diameter d of the light receiving portion R of the temperature sensitive element 9.
[0017]
Thus, of the incident infrared light that has passed through the first infrared transmissive window 4, only infrared light having a specific wavelength passes through the second infrared transmissive window 20 and reaches the light receiving unit R. At this time, the heat generated by the second infrared transmissive window 20 by the incident infrared rays can be efficiently released to the upper and lower two heat sinks 21 and 16, and the infrared rays radiated by the heat are eliminated. The temperature sensitive element 9 is sensitive only to infrared light having a specific wavelength that has passed through the two infrared transmissive windows 20. Therefore, it is possible to obtain a thermal infrared detector with good visual field characteristics.
[0018]
Further, since the semiconductor container 1 made of silicon, germanium, or the like, which is the base material of the first infrared transmissive window 4, and the conductive container 1 are electrically coupled via the solder a, the shielding property against electromagnetics can be improved. You won't be subject to noise. Therefore, a thermal infrared detector that operates stably over a long period of time can be obtained.
[0019]
Further , the lower heat sink 16 and the lead pin 6 are thermally coupled.
[0020]
[0021]
The present invention is not limited to the above-described embodiments, and can be implemented with various modifications. For example, the can 2 may be formed of an iron-based alloy such as aluminum or fernico .
[0022]
Further, an electrically insulating coating having a thickness of about several μm may be applied to the surface of the heat sinks 16 and 30.
[0023]
【The invention's effect】
In this invention, the upper and lower two heat sinks and the two infrared transmissive windows are thermally coupled, and the heat generated by the second infrared transmissive window due to incident infrared rays can be efficiently released to the upper and lower two heat sinks, Incidence of infrared rays radiated by the heat generated by the second infrared transmissive window to the thermosensitive element can be prevented.
[0024]
Thus, since the temperature sensitive element is sensitive only to the infrared rays transmitted from the first infrared transmitting window to the second infrared transmitting window among the infrared rays radiated from the object, the output error can be reduced. In addition, it is possible to obtain a thermal infrared detector with good visual field characteristics.
[0025]
Further, since the semiconductor, which is the base material of the first infrared transmitting window, and the container of the conductor are electrically coupled, the shielding property against electromagnetics can be improved and no electrical noise is received. Therefore, a thermal infrared detector that operates stably over a long period of time can be obtained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a first embodiment of a thermal infrared detector of the present invention.
FIG. 2 is an exploded perspective view of the thermal infrared detector.
FIG. 3 is a plan view schematically showing a configuration of a temperature sensitive element used in the thermal infrared detector.
FIG. 4 is a cross-sectional view showing a conventional example .
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Container, 2 ... Can, 3 ... Stem, 4,20 ... Infrared transparent window, 6 ... Lead pin, 9 ... Temperature-sensitive element, 13 ... Cold junction, 16 , 21 ... Heat sink, 22 ... Hole, R ... Feel The light receiving part of the temperature element.

Claims (4)

In a container composed of a can in which a first infrared transmitting window is coupled so as to be electrically conductive and a stem having a lead pin for signal extraction extending vertically in an electrically insulated state, the top and bottom 2 In a thermal infrared detector in which a thermosensitive element made of a thermopile is disposed so as to be thermally coupled to both the heat sinks while being sandwiched between two heat sinks , the stem is made of copper. At the same time, the lower heat sink is made of copper and formed into a bowl shape, and the lower heat sink of the lower part is fixed to the upper surface of the stem with a good heat conductive adhesive. is, and the upper heat sink is formed in a donut shape having a hole in its central portion with copper, on the upper surface of the upper heat sink, good thermal conductivity semiconductor as a base material, the base material Of the incident infrared rays having passed through the first infrared transparent window on the surface, the forming a wavelength-selective multilayer film to bring the light receiving portion of the temperature-sensitive element by transmitting only the infrared light of a specific wavelength 2 The infrared transparent window is fixed with a heat conductive adhesive in a state of covering the hole in the center of the upper heat sink, and at least the lower heat sink and the lead pin are thermally coupled. Thermal infrared detector. 2. The heat according to claim 1, wherein the first infrared transmitting window and the can are joined by soldering, the can and the stem are joined by pressure welding or welding, and the lower heat sink and the stem are thermally coupled. Type infrared detector.   The thermal infrared detector according to claim 1 or 2, wherein a diameter of a hole of the upper heat sink is set to be 1.5 times or less of a diameter of a light receiving portion of the temperature sensing element. The heat according to any one of claims 1 to 3, wherein the first infrared transmitting window is configured by using a semiconductor as a base material and forming coating films that transmit infrared light on both surfaces of the base material. Type infrared detector.

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