JPH0634448A - Radiation thermometer - Google Patents

Abstract

PURPOSE:To obtain a high-performance thermometer without providing a separate means for measuring a room temperature by providing an infrared ray detection part and a temperature-sensitive part on one surface of a semiconductor substrate and forming a recessed cut-out part by eliminating the substrate by etching at a part corresponding to the lower part of the infrared ray detection part on the other surface of the substrate. CONSTITUTION:An infrared ray detection part 2 and a temperaturesensitive part 3 are provided on one surface of a semiconductor substrate 1 and a recessed cut-out part K is formed at a part corresponding to the lower part of the detection part 2 on the other surface of the substrate 1 by eliminating the substrate 1 by etching. The detection part 2 and the temperature-sensitive part 3 consist of an infrared ray detection thermistor 4 with equal temperature characteristics, a temperature-sensitive thermistor 5, amorphous silicon etc. Then, an infrared ray absorption film 9 is formed on the surface of a thermal insulation thin film 6, a plurality of electrodes 7 and 8, and further the detection surface 2. The detection part 2 and the substrate 1 are thermally isolated by the thin film 6, thus increasing temperature rise of the detection part 2 owing to infrared ray radiation for improved sensitivity. Also, the recessed cut-out part K allows a thermally isolated space with a high heat-insulating effect to be formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation thermometer for measuring temperature without contact.

[0002]

2. Description of the Related Art Conventionally, as a generally used non-contact thermometer for measuring temperature, an infrared radiation thermometer for detecting temperature of infrared radiation from an object to be measured is known. This uses a pyroelectric element, a thermopile, etc. for the infrared detecting section, but a means for measuring the reference temperature, in other words, the current environmental temperature (room temperature) is additionally required.

FIG. 7 shows a block diagram of a conventional radiation thermometer using a pyroelectric element for an infrared detecting section. With respect to this figure, the procedure for measuring the temperature of the object to be measured will be described. Infrared rays X emitted from the object to be measured are condensed by the optical system A, and the incident infrared rays are blocked by the chip B to cause a temperature change, The temperature change is detected by the pyroelectric element (infrared ray detecting element) C, and the output from the pyroelectric element C changes due to the temperature difference from the reference room temperature.
The surface temperature of the object to be measured is measured by combining with the room temperature obtained by the reference temperature detecting element D. In FIG. 6, E is a sync signal generation, F is an amplifier, G is an amplified phase detection, H is a combination, and I is an output.

[0004]

The conventional radiation thermometer described above detects a temperature change due to infrared rays radiated from an object to be measured as an output of the infrared detection element.
What is obtained by the infrared detecting element is the temperature difference from the room temperature, and in order to know the temperature of the surface of the measured object, the room temperature must be measured by another means.

According to the present invention, in order to solve such a problem, an object is to provide a high-performance radiation thermometer with a simple structure without providing another means for measuring the room temperature. There is.

[0006]

To achieve the above object, the radiation thermometer of the present invention comprises an infrared detecting section and a temperature sensitive section on one side of a semiconductor substrate, and the other side of the semiconductor substrate. On one side, at a location corresponding to the lower portion of the infrared detection section, the semiconductor substrate is removed by etching to form a recessed section, but the infrared detection section and the temperature sensing section are composed of a thermistor. The infrared detecting section and the temperature sensing section respectively form a bridge circuit connected in series with a fixed resistor.

[0007]

The operation of the present invention will be described. Since the infrared detection unit and the temperature sensing unit provided on one side of the semiconductor substrate are in a state of being thermally separated, the temperature rise of the infrared detection unit due to infrared radiation is large, and the other side of the semiconductor substrate is , At the location corresponding to the bottom of the infrared detector,
The semiconductor substrate is removed by etching to form a recessed portion, thereby forming a heat separation space having a high heat insulating effect.

[0008]

Embodiments of the present invention will be described in detail below with reference to the drawings. 1 (a) is a plan view of an infrared detection unit and a temperature sensing unit of a radiation thermometer of the present invention, FIG. 1 (b) is a sectional view of the same, and FIG. 2 (a) is a radiation temperature of the present invention. The top view of the infrared detection part and temperature sensing part which show the other example of a meter, (b) has shown sectional drawing same as the above.

In FIG. 1, an infrared detecting section 2 and a temperature sensing section 3 are provided on one side of a semiconductor substrate 1. On the other side of the semiconductor substrate 1, a semiconductor is provided at a portion corresponding to a lower portion of the infrared detecting section 2. This shows a structure in which the substrate 1 is removed by etching to form a recess k. In addition, in FIG.
By the semiconductor process, in addition to the structure shown in FIG. 1, fixed resistors R, R are further formed on one surface of the same semiconductor substrate 1 to form a bridge circuit as shown in FIG.

The infrared detecting section 2 and the temperature sensing section 3 are formed on one surface of the semiconductor substrate 1 by using a thin film forming technique and a fine processing technique similar to the semiconductor process in the usual IC circuit production. Further, the infrared detecting section 2 and the temperature sensing section 3 include an infrared detecting thermistor 4 and a temperature sensing section thermistor 5 having equal temperature characteristics, a thin film resistor 6 made of amorphous silicon or polycrystalline silicon,
It is composed of a plurality of electrodes 7 and 8 formed on this surface, and further, an infrared absorption film 9 is formed on the surface of the infrared detection section 2.
Is formed.

The thin-film resistor 6 has a low thermal conductivity and is made of a material suitable for a semiconductor process, such as a silicon oxide film, a silicon nitride film, or a multilayer film of these films. The thin film resistor 6 thermally separates the infrared detecting section 2 and the semiconductor substrate 1, and the temperature rise of the infrared detecting section 2 due to infrared radiation increases, and the sensitivity becomes better accordingly. Of. Since the semiconductor substrate 1 is removed by etching to form the recess k, it is possible to form a heat separation space having a high heat insulation effect.

Since the temperature sensing portion 3 does not absorb infrared rays, it has almost no sensitivity to incident infrared rays. Even if some heat is absorbed, the absorbed heat diffuses to the semiconductor substrate 1. Since it does not contribute to the temperature change of the temperature sensing part thermistor 5, the resistance value of the temperature sensing part thermistor 5 shows a resistance value corresponding to room temperature. The infrared rays that have entered the infrared detection section 2 are absorbed by the infrared absorption film 9 and the temperature of the infrared detection thermistor 4 changes, so that the electric resistance value changes. Therefore,
In FIG. 3, the room temperature can be measured by the potential at point b in the electric circuit diagram showing the first embodiment of the radiation thermometer of the present invention. If the sensitivity of the infrared detecting section 2 (increased temperature of the infrared detecting thermistor 4 per unit infrared incident quantity) is known, the incident infrared quantity to the infrared detecting section 2 can be obtained, and measured by the Stefan-Boltzmann law. The temperature of the object is obtained.

The above will be briefly described. The power supply voltage is V, the resistance and the fixed resistance of the infrared detection thermistor 4 at room temperature To are R, and the resistance change rate of the infrared detection thermistor 4 is B (B: constant). Further, at the ambient temperature Te, the potentials at the points a and b when a certain infrared ray is input are Vr and Ve. The resistance Re of the temperature sensing part thermistor 5 at this time can be expressed by the following equation from the potential Ve at the point b.

Re = R · (V−Ve) / Ve Therefore, the room temperature Te can be expressed by the following equation. Te = 1 / {(1 / To) −ln (R / Re) / B) On the other hand, the resistance Rr of the infrared detection thermistor 4 is Rr = Rf · (V−Vr) / Vr from the potential Vr at the point a. Therefore, the surface temperature Ts of the infrared detection thermistor 4
Is Ts = 1 / {(1 / To) -ln (R / Rr) / B).

Here, when the thermistor temperature change Δt per unit input is known, the infrared ray incident amount on the thermistor is given by the following equation, and the incident amount and the room temperature and the temperature of the object to be measured according to the Stefan-Boltzmann law. Can be obtained. Pr = (Ts-Te) / Δt FIG. 4 is an electric circuit diagram showing a second embodiment of the radiation thermometer of the present invention. As in the case of the first embodiment described above, the temperature sensing part thermistor 5 exhibits a resistance value corresponding to room temperature, and the infrared detection thermistor 4 exhibits a resistance change due to room temperature and incident infrared rays. Then, in the circuit of the thermistor Th and the fixed resistance R shown in FIG. 5, the relationship of the output voltage V ₀ with respect to room temperature is shown in FIG. This indicates that the output voltage is larger and the accuracy is higher near the room temperature than when the room temperature is low or high.

In the electric circuit diagram of FIG. 4, the temperature sensing part thermistor 5 is used.
And the infrared detection thermistor 4 are connected in series, and a difference from the reference voltage due to the fixed resistance R is detected, so that a certain accuracy can be maintained without being affected by room temperature. However, in order to know the room temperature, it is necessary to add a temperature sensitive part.

[0017]

The present invention is constructed as described above and has the following effects. That is, since the infrared detecting section and the temperature sensitive section provided on one side of the semiconductor substrate are in a state of being thermally separated, the temperature rise of the infrared detecting section due to infrared radiation becomes large, and the other side of the semiconductor substrate Then
At the location corresponding to the lower part of the infrared detector, the semiconductor substrate is removed by etching to form a recessed portion to form a heat separation space with a high heat insulation effect.Therefore, provide another means to know the room temperature. In addition, it has the feature that a high-performance radiation thermometer can be obtained with a simple configuration.

[Brief description of drawings]

FIG. 1A is a plan view of an infrared detection unit and a temperature sensing unit of a radiation thermometer of the present invention, and FIG. 1B is a sectional view of the same.

FIG. 2A is a plan view of an infrared detection unit and a temperature sensing unit showing another example of the radiation thermometer of the present invention, and FIG. 2B is a sectional view of the same.

FIG. 3 is an electric circuit diagram showing a first embodiment of a radiation thermometer of the present invention.

FIG. 4 is an electric circuit diagram showing a second embodiment of the radiation thermometer of the present invention.

FIG. 5 is an electric circuit diagram of a thermistor and a fixed resistor.

6 is a diagram showing a relationship of an output voltage with respect to room temperature in the electric circuit diagram of FIG.

FIG. 7 is a block diagram of a conventional radiation thermometer using a pyroelectric element for an infrared detection unit.

[Explanation of symbols]

 1 Semiconductor Substrate 2 Infrared Detector 3 Temperature Sensing 4 Infrared Detector Thermistor 5 Temperature Sensing Thermistor 6 Thin Film Resistor k Recessed

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[Procedure amendment]

[Submission date] October 12, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

The infrared detecting section 2 and the temperature sensing section 3 are formed on one surface of the semiconductor substrate 1 by using a thin film forming technique and a fine processing technique similar to the semiconductor process in the usual IC circuit production. Further, the infrared detecting section 2 and the temperature sensing section 3 include an infrared detecting thermistor 4 and a temperature sensing section thermistor 5 having the same temperature characteristics, and thermal insulation.
The thin film 6 is composed of a plurality of electrodes 7 and 8 formed on the surface of the thin film 6, and an infrared absorbing film 9 is formed on the surface of the infrared detecting section 2.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

Re = R · (V−Ve) / Ve Therefore, the room temperature Te can be expressed by the following equation. Te = 1 / {(1 / To) −ln (R / Re) / B) On the other hand, the resistance Rr of the infrared detection thermistor 4 is Rr = R · (V−Vr) / Vr from the potential Vr at the point a. Therefore, the surface temperature Ts of the infrared detection thermistor 4
Is Ts = 1 / {(1 / To) -ln (R / Rr) / B).

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1A is a plan view of an infrared detection unit and a temperature sensing unit of a radiation thermometer of the present invention, and FIG. 1B is a sectional view of the same.

FIG. 2A is a plan view of an infrared detection unit and a temperature sensing unit showing another example of the radiation thermometer of the present invention, and FIG. 2B is a sectional view of the same.

FIG. 3 is an electric circuit diagram showing a first embodiment of a radiation thermometer of the present invention.

FIG. 4 is an electric circuit diagram showing a second embodiment of the radiation thermometer of the present invention.

FIG. 5 is an electric circuit diagram of a thermistor and a fixed resistor.

6 is a diagram showing a relationship of an output voltage with respect to room temperature in the electric circuit diagram of FIG.

FIG. 7 is a block diagram of a conventional radiation thermometer using a pyroelectric element for an infrared detection unit.

[Explanation of reference numerals] 1 semiconductor substrate 2 infrared detection section 3 temperature sensing section 4 infrared detection section thermistor 5 temperature sensing section thermistor 6 thermal insulation thin film k concave

[Procedure amendment 4]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

Claims (2)

[Claims] 1. A semiconductor substrate is provided with an infrared detecting section and a temperature sensing section on one side, and the semiconductor substrate is provided on the other side of the semiconductor substrate at a location corresponding to a lower portion of the infrared detecting section. A radiation thermometer, characterized in that a recess is formed by removing it by etching. 2. The thermistor constitutes an infrared detecting section and a temperature sensing section, and the infrared detecting section and the temperature sensing section respectively constitute a bridge circuit connected in series with a fixed resistor. The radiation thermometer according to 1.