JPH055658A - PN junction type temperature sensor - Google Patents

Abstract

(57) [Summary] [Purpose] The temperature of an object can be accurately detected, and the responsiveness of temperature detection can be improved. [Structure] When infrared rays corresponding to the temperature of the object to be measured are radiated, the tip 3B side of each N-type semiconductor portion 3 made of a plurality of silicon carbide fibers absorbs the infrared rays and rises in temperature. The temperature ranges from the tip 3B of each N-type semiconductor part 3 to the base 3
Conducted toward A. Thereby, each of the N-type semiconductor portions 3
The temperature of the junction between the P-type semiconductor section 2 and the P-type semiconductor section 2 rises, and the current value flowing from the P-type semiconductor section 2 to each N-type semiconductor section 3 via the junction increases. Then, the ammeter detects the current value and outputs a detection signal to the control unit, and the control unit reads the temperature from the temperature-current map based on the detection signal from the ammeter and displays the temperature on the display. To display.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is suitable for detecting temperature such as product temperature and engine combustion temperature.
The present invention relates to an N-junction type temperature sensor.

[0002]

2. Description of the Related Art Generally, in the field of industry and the like, the temperature of a product or the like is detected by a temperature sensor in order to perform quality control, characteristic test, etc. of the product. As the temperature sensor, a thermocouple, a resistance temperature detector, etc. are known.

[0003]

By the way, in the above-mentioned temperature sensor according to the prior art, the temperature is measured by contacting the object to be measured. Therefore, when the object is small, the temperature sensor itself has a heat capacity to measure the object. There is a problem in that the temperature changes and the detection accuracy drops significantly. Further, since the thermocouple and the like have low responsiveness, when the temperature of the object changes at high speed, there is a problem that the temperature change cannot be followed.

The present invention has been made in view of the above-mentioned problems of the prior art, and provides a PN junction type temperature sensor capable of accurately detecting the temperature of an object and improving the responsiveness of temperature detection. The purpose is to do.

[0005]

The structure adopted by the present invention to solve the above-mentioned problems is a cylindrical casing,
A P-type semiconductor portion provided in the casing and formed in a flat plate shape as a P-type semiconductor, and a cylindrical shape using silicon carbide fiber as an N-type semiconductor, and the base end side is joined to the P-type semiconductor portion. The tip side is composed of an N-type semiconductor portion provided so as to protrude from the tip of the casing to the outside, and a pair of electrodes for supplying a voltage between the P-type semiconductor portion and the N-type semiconductor portion.

[0006]

The tip side of the N-type semiconductor portion absorbs infrared rays radiated from the object to be measured according to the temperature of itself and rises in temperature, and this temperature is conducted from the tip side to the base side of the N-type semiconductor portion. Then, the temperature of the junction between the N-type semiconductor portion and the P-type semiconductor portion rises. As a result, the value of the current flowing from the P-type semiconductor section to the N-type semiconductor section via the junction increases, and the temperature of the measurement object can be detected by detecting this current value.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.

In the figure, reference numeral 1 denotes a casing formed of an insulating material such as resin or ceramics in a cylindrical shape with a lid, and the casing 1 is located at the base end side and fixed to a mounting bracket (not shown) or the like. A large diameter portion 1A, and a small diameter portion 1B projecting from the large diameter portion 1A toward the tip side,
The small-diameter portion 1B is formed on the inner peripheral side and is substantially configured of a housing hole 1C that houses a P-type semiconductor portion 2 and an N-type semiconductor portion 3 described later, and the casing 1 has a lead plate 6 described later. Insertion holes 1D, 1D through which the holes are inserted are formed.

Reference numeral 2 denotes a P-type semiconductor portion provided in the accommodation hole 1C of the casing 1. The P-type semiconductor portion 2 is formed of P-type silicon in a flat plate shape as shown in FIG.
The P-type semiconductor portion 2 has one surface side (right side in the drawing).
The N-type semiconductor portion 3 is provided by being joined to the other surface side (in the figure,
On the left side), an electrode 4 for a P-type semiconductor section described later is provided.

.. are located in the accommodation holes 1C of the casing 1, and as shown in FIG. 2, a plurality of N-type semiconductor portions provided on one surface side of the P-type semiconductor portion 2 are spaced apart from each other. Each of the N-type semiconductor portions 3 is formed in a columnar shape from silicon carbide fiber (SiC) as an N-type semiconductor. Also,
The outer peripheral side of the base end 3A of each N-type semiconductor portion 3 is a P-type semiconductor portion 2
The front end 3B side of each N-type semiconductor portion 3 is provided so as to project to the outside from the front end of the small diameter portion 1B of the casing 1. The silicon carbide fiber is black and has a thickness of 10 μm.
It is a fiber having a small diameter of about m and has thermistor characteristics in which the resistance value changes with heat (infrared rays).

Reference numeral 4 denotes a P-type semiconductor portion electrode provided on the other surface side of the P-type semiconductor portion 2, and 5 denotes an N-type semiconductor portion electrode provided on one surface side of each N-type semiconductor portion 3, respectively. Each of the electrodes 4 and 5 is connected to a DC power source 8 and the like described later via lead plates 6 and 6 made of a conductive material such as gold alloy.

Reference numeral 7 denotes a disc-shaped cover which is provided by covering the opening of the accommodation hole 1C of the casing 1 and is made of an insulating material such as ceramics.
As shown in FIG. 5, an insertion hole 7A through which the tip end side of each N-type semiconductor portion 3 is inserted is formed in an elongated hole shape on the inner peripheral side thereof.

Reference numeral 8 denotes a DC power source provided outside the casing 1, and the DC power source 8 is a P type on the plus side via the electrodes 4 and 5 and the lead plates 6 as shown in FIG. It is connected to the semiconductor section 2 and the negative side is connected to each N-type semiconductor section 3. Then, the DC power source 8 is connected to a control unit 10 described later, and applies a predetermined DC voltage to each semiconductor section 2 and 3 via each electrode 4 and 5 based on a control signal from the control unit 10. To do.

Reference numeral 9 denotes an ammeter provided between the DC power source 8 and the N-type semiconductor part electrode 5, and the ammeter 9 is connected to the control unit 10. The ammeter 9 detects the value of the current flowing from the P-type semiconductor section 2 toward each N-type semiconductor section 3, and outputs this detection signal to the control unit 10.

Reference numeral 10 denotes a control unit composed of a CPU and the like as a microcomputer, and a storage area 10A of the control unit 10 stores a temperature-current map 11 shown in FIG. An ammeter 9 is connected to the input side of the control unit 10, and a DC power source 8 and a display (not shown) are connected to the output side of the control unit 10. here,
As shown in FIG. 5, the temperature-current map 11 shows the temperature of the junction formed between the P-type semiconductor section 2 and each N-type semiconductor section 3, and the P-type semiconductor section 2 via the junction. The relationship with the current value flowing in each N-type semiconductor section 3 is stored as a map. Then, the control unit 10 reads the detection signal from the ammeter 9, reads the temperature from the temperature-current map 11 based on the detection signal, and displays this temperature on the display as the temperature of the measurement object.

The PN junction type temperature sensor according to the present embodiment has the above-mentioned configuration, and when infrared rays are emitted from the object to be measured according to its own temperature, the tip 3B side of each N type semiconductor portion 3 is exposed. The infrared rays are absorbed and the temperature rises, and this temperature is conducted from the tip 3B to the base 3A of each N-type semiconductor portion 3. As a result, the temperature of the junction between the N-type semiconductor section 3 and the P-type semiconductor section 2 rises, and the value of the current flowing from the P-type semiconductor section 2 to the N-type semiconductor section 3 via the junction increases. .. Then, the ammeter 9 detects this current value and outputs a detection signal to the control unit 10, and the control unit 10 reads the temperature from the temperature-current map 11 based on the detection signal from the ammeter 9, This temperature is displayed on the display.

Thus, according to this embodiment, the infrared rays radiated from the object to be measured are absorbed by the tip 3B side of each N-type semiconductor section 3 and converted into a temperature, and this temperature is converted into each temperature. To the casing 1 side via the
By increasing the temperature of the junction between the semiconductor parts 3 and 3, it is possible to effectively change the value of the current flowing between the semiconductor parts 2 and 3 through the junction according to the temperature of the object to be measured. The unit 10 can read the temperature from the temperature-current map 11 based on the detection signal detected by the ammeter 9 to detect the temperature of the measurement target. As a result, since the temperature of the measurement target can be detected in a non-contact manner, the temperature of the measurement target can be accurately detected even when the heat capacity of the measurement target is small.

Each N-type semiconductor portion 3 has a diameter of 10 μm.
Since it is made of silicon carbide fiber with a small diameter and has a structure in which a plurality of fibers are arranged, infrared rays from the measurement object can be quickly absorbed to raise the temperature, and the temperature of the measurement object can be detected with high responsiveness. can do.

In the above embodiment, the electrode 4 for the P-type semiconductor portion is formed thinner than the electrode 5 for the N-type semiconductor portion, but instead of this, the thickness of each electrode 4, 5 is changed. The dimensions may be formed to be substantially equal.

Further, in the above-mentioned embodiment, the cover 7 is described as being formed with the elongated hole-shaped insertion hole 7A through which the tip 3B of each N-type semiconductor portion 3 is inserted. It is also possible to form the same number of insertion holes as the respective N-type semiconductor portions 3 and insert the tips 3B of the N-type semiconductor portions 3 into the respective insertion holes.

Further, in the above-described embodiment, the configuration in which the N-type semiconductor 3 is arranged in a flat plate is illustrated, but instead of this, for example, a plurality of silicon carbide fibers may be bundled into one. Alternatively, it may be formed into a single flat plate.

[0022]

As described in detail above, according to the present invention, a cylindrical casing, a P-type semiconductor portion provided in the casing and formed in a flat plate shape as a P-type semiconductor, and an N-type semiconductor are provided. An N-type semiconductor portion formed in a columnar shape using silicon carbide fibers, the base end side of which is joined to the P-type semiconductor portion and the tip end side of which is provided outside the tip of the casing to the outside.
Since the P-type semiconductor portion and the pair of electrodes for supplying a voltage between the P-type semiconductor portion and the N-type semiconductor portion are configured, when the infrared radiation is emitted from the measurement object according to the temperature of the measurement object, The tip side absorbs this infrared ray and rises in temperature. Then, this temperature is conducted to the base end side of the N-type semiconductor portion,
The temperature of the junction between the p-type semiconductor part and the p-type semiconductor part rises. As a result, the value of the current flowing from the P-type semiconductor portion to the N-type semiconductor portion via the junction increases, so that by detecting this current value, the temperature of the measuring object can be detected accurately and with good responsiveness. be able to.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a PN junction type temperature sensor according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a plan view in the direction of arrow III-III in FIG.

FIG. 4 is a block diagram showing a circuit configuration.

FIG. 5 is a characteristic diagram showing a temperature-current map.

[Explanation of symbols]

 1 Casing 2 P-type semiconductor part 3 N-type semiconductor part 3A Base end 3B Tip 4 P-type semiconductor electrode 5 N-type semiconductor electrode

Claims (1)

Claim: What is claimed is: 1. A cylindrical casing, a P-type semiconductor portion formed in the casing and having a flat plate shape as a P-type semiconductor, and a silicon carbide fiber as an N-type semiconductor. An N-type semiconductor portion formed in a columnar shape, the base end side of which is joined to the P-type semiconductor portion and the tip end side of which is provided to project outward from the tip of the casing; and the P-type semiconductor portion and the N-type semiconductor portion. P composed of a pair of electrodes for supplying a voltage between them
N-junction type temperature sensor.