JP2010175442A - Thermopile type infrared detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that a conventional method employs the calculation of a detection temperature by adjusting an output by using a thermopile type infrared detector in line with emissivity of a detection object and reveals a fall in temperature measurement accuracy of the detection object when the emissivity is changed by an operation of changing the detection object. <P>SOLUTION: The configuration of this detector in which a reflectivity measuring element such as a photo-reflector or the like and a reflectivity measuring circuit are mounted on the same board, is characterized in that a detection output from the thermopile type infrared detector is subjected in an emissivity compensating processing, based on an output measured by the reflectivity measuring circuit. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a thermopile infrared detector that measures temperature with high accuracy regardless of the surface state of an object by measuring and correcting the reflectance of the object.

Conventional thermopile infrared detectors that have been used in the past accurately detect the temperature of an object by adjusting the output according to the emissivity of the object to be detected.
Therefore, if the emissivity of the temperature measurement object is different, the adjustment output will be shifted, so the reflectance of the temperature measurement object will be measured separately using a photoreflector, etc., to the detection temperature in the thermopile infrared detector. The detection output is corrected externally by providing a circuit and obtaining the emissivity.

Japanese Patent Application No. 2008-163651

In the conventional method, the detection temperature is calculated by adjusting the output with a thermopile infrared detector in accordance with the emissivity of the detection object, so if the emissivity changes due to the change of the detection object, the detection object There is a problem that temperature measurement accuracy decreases.
FIG. 3 shows a block schematic diagram of calculation of the detected temperature of the conventional thermopile type infrared detecting device.

  In order to solve the above-mentioned problems, the present invention has a reflectance measuring element such as a photoreflector and a reflectance measuring circuit mounted on the same substrate, and a thermopile infrared detection is performed based on the output measured by the reflectance measuring circuit. It is characterized by a configuration in which emissivity correction processing is performed on the detection output from the apparatus.

  In the present invention, a reflectance measuring element such as a photoreflector and a reflectance measuring circuit are mounted on the same substrate in a single circuit substrate, and the detection output from the thermopile infrared detection device. By performing the emissivity correction process, the object temperature can be accurately measured regardless of the surface state of the object.

1 is a circuit diagram of a thermopile type infrared detection device including an emissivity correction circuit according to Embodiment 1 of the present invention. FIG. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of an emissivity correction block of a thermopile type infrared detecting device including an emissivity correction circuit according to a first embodiment of the present invention. It is a block schematic diagram of detection temperature calculation of the conventional thermopile type infrared detecting device. It is a thermopile signal output characteristic in the emissivity of a thermopile type infrared detector. It is a reflectance measurement output characteristic in a reflectance measurement circuit. It is a thermopile output characteristic at the time of performing the emissivity correction which concerns on Example 1 of this invention. It is a list of each output characteristic concerning Example 1 of the present invention.

Hereinafter, the present invention will be described in detail with reference to the drawings.
The thermopile type infrared detector of the present invention includes a reflectance measuring element such as a photoreflector for calculating the emissivity of a detection target by measuring the reflectance of the detection target, and the reflectance measurement circuit on the same substrate. Provided by the shape mounted above. FIG. 1 shows a circuit diagram of a thermopile type infrared detection device equipped with an emissivity correction circuit as a thermopile type infrared detection device. FIG. 2 shows a schematic diagram of the emissivity correction block.

Details of the present invention according to Example 1 will be described below. FIG. 1 is a circuit of a thermopile infrared detector equipped with an emissivity correction circuit.
In the present embodiment, the amount of infrared incident on the thermopile chip that enables the temperature of the detection target to be detected by measuring the amount of infrared radiation radiated from the detection target by receiving infrared rays is defined from the detection target projection area. Uses a planar filter made of silicon to guide the infrared detection area by optical design, a metallic CAN case with an infrared transmission window, a header with lead terminals electrically connected to a thermopile chip, and external environmental changes and electromagnetic interference Reflection of the object to be detected by a photo reflector using an LED for the light emitting part and a phototransistor for the light receiving part on the same substrate as the thermopile infrared detector, which is a general structure with a hermetic seal to prevent The emissivity of the object to be detected is calculated by measuring the rate, and the thermopile sensor is output at the calculated emissivity. It has a structure of the thermopile-type infrared detection device which performs correction calculation at the same substrate a correction to. In this embodiment, silicon is used as the optical system substrate, but a substrate having wavelength dependency such as glass may be used.

In this embodiment, a plane filter is used as an optical design. However, for example, a plano-convex lens, a plano-concave lens, a biconvex lens, or a biconcave lens may be used.
Moreover, as a thermopile type infrared detection device, not only a one-area detection thermopile chip that can measure the amount of radiated infrared rays of an object and detect the temperature of the object, but also a dual type thermopile having two infrared light receiving parts. Type infrared detectors, infrared detectors like inline type thermopile array type infrared detectors with infrared detectors arranged in a line, temperature detectors of matrix type thermopile matrix type infrared detectors with infrared detectors arranged in a matrix A multi-element type thermopile type infrared detecting device having 1 to 16 light receiving portions may be used.

Using the thermopile type infrared detector of the present invention, heat source temperature: 100 ° C. object A (emissivity: 1.0), object B (emissivity: 0.5), object C (emissivity: 0.3) Measured.
FIG. 4 is a thermopile electromotive force characteristic in a difference in emissivity between the objects A, B, and C of the thermopile infrared detector. In the thermopile infrared detector, when the emissivity of the detection target is 1.0, the output is 1.0 V, the emissivity is 0.5, the output is 0.5 V, and the emissivity is 0.3. 0.3V.
FIG. 5 shows reflectance measurement output characteristics of the objects A, B, and C in the reflectance measurement circuit. When the emissivity of the object is measured using a photo reflector or the like, the object A is 0.0 V, the object B is 0.5 V, and the object C is 0.7 V. Since only the photoreflector or the like has a low output voltage level, an inverting amplifier circuit as shown in FIG. 1 is provided to amplify and adjust the output so as to obtain the emissivity output.
FIG. 6 shows thermopile electromotive force characteristics when objects A, B, and C are detected when the emissivity correction process of the present invention is performed. As shown in FIG. 6, the thermopile electromotive forces of the objects A, B, and C are all 1.0 V regardless of the emissivity of the objects.

The circuit as shown in FIG. 1 for adding the reflectance measurement output to the thermopile electromotive force in order to compensate for the attenuated thermopile signal output by the emissivity of the object based on the characteristics shown in FIGS. By adopting the configuration, it is possible to perform emissivity correction processing on the same substrate, and it was confirmed that the thermopile electromotive force is constant even if there is a difference in emissivity between the objects A, B, and C.
FIG. 7 shows a list of output characteristics of the embodiment.
FIG. 4 is a graph showing the output characteristics at the emissivity of the conventional thermopile infrared detector, FIG. 6 is a comparison of the output characteristics graph at the emissivity of the thermopile infrared detector of the present invention, and FIG. As shown, the effect of the emissivity correction processing circuit on the same substrate was confirmed.

DESCRIPTION OF SYMBOLS 1 Thermopile element 2 Thermistor 3 Photo reflector 4 Inverting amplification amplifier 5 Emissivity addition, thermopile electromotive force amplification amplifier

Claims (1)

  The thermopile infrared detector has a reflectivity measurement circuit that measures the reflectivity of the object to be detected on the same substrate, and outputs a thermopile signal that has undergone emissivity correction processing on the same substrate. A thermopile infrared detector.

Images