JPH10267754A - Scan type infrared ray detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a infrared ray from only a heat source regardless of the existence of infrared radiation from a background by arranging an infrared ray detecting element array in two lines and making scanning to the heat source. SOLUTION: An infrared ray sensor 2 is composed by arranging the first and the second infrared ray detecting element arrays in parallel to each other, and scanning is carried out to a heat source 11 in a scanning direction 9 to amplify detection signals detected through the first and the second infrared ray detecting element to a specified level by each amplifier 5, and the difference of each detection signal is decided in an arithmetic circuit 6 to output the result of computation 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning infrared detector capable of effectively detecting infrared radiation from a heat source existing in background infrared radiation by scanning an infrared sensor.

[0002]

2. Description of the Related Art Conventionally, as a method of detecting infrared rays,
A single-element infrared sensor, a one-dimensional infrared detection element array, and an infrared image sensor are used, each of which detects infrared radiation obtained by superimposing infrared radiation from a heat source on infrared radiation from a background. In addition, a complicated signal processing circuit was required to extract only the target infrared radiation from the output signal of the infrared sensor. Further, it has been necessary to selectively use the detection element depending on the use in the case where the response performance of the infrared detection element is relatively slow such as a pyroelectric type and the response performance is relatively fast such as a quantum type.

[0003]

SUMMARY OF THE INVENTION The present invention eliminates the above-mentioned complicated signal processing circuit and solves these problems by improving the constitution of the infrared sensor. It is an object of the present invention to provide a scanning infrared detector capable of effectively detecting only target infrared radiation from background infrared radiation with a simple arithmetic circuit, regardless of the response performance of the scanning infrared detector.

[0004] Other objects and novel features of the present invention will become apparent in embodiments described later.

[0005]

In order to achieve the above object, a scanning infrared detector according to the present invention is provided with an infrared sensor which scans in a fixed direction and detects infrared radiation from a heat source via a lens. And an arithmetic circuit for calculating an output signal from an amplifier that amplifies the output from the infrared sensor.

In the above-mentioned scanning type infrared detector, the infrared sensor is constituted by arranging a plurality of infrared detecting element arrays in which infrared detecting elements are linearly arranged, and detecting infrared rays from a heat source existing in infrared radiation from a background. A configuration may be adopted in which only radiation is signal-enhanced by the interval between the plurality of infrared detection element arrays.

The infrared detecting element array may be constituted by arranging pyroelectric infrared detecting elements having relatively slow response characteristics, and the arithmetic circuit may calculate the difference between the outputs of the plurality of infrared detecting element arrays. Thereby, the response characteristic can be speeded up.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the scanning infrared detector according to the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of a scanning infrared detector according to the present invention, in which an infrared radiation 13 of a heat source 11 (including a lower temperature than the background) contained in an infrared radiation 12 of a background 10 is provided. It is a schematic diagram which detects. In this figure,
Reference numeral 8 denotes an infrared detector, which scans in a scanning direction 9 (for example, at a constant speed in the horizontal direction). The infrared detector 8 supports the lens 1 and the infrared sensor 2 in the case 8a.
And a housing 4 in which the infrared sensor 2
And an arithmetic circuit 6 for calculating the output of the amplifier 5. 7 is an operation output of the operation circuit 6. A hole 3 is formed in a portion of the case 8a corresponding to the front surface of the lens 1.

FIG. 2 shows an example in which an infrared sensor 2 having a five-element two-row array used in an experiment for realizing the present invention is used.
As shown in the figure, the infrared sensor 2 includes a first infrared detecting element array 14 in which infrared detecting elements 18 to 22 are linearly arranged in one line, and an infrared detecting element 23 to
27, and a second infrared detecting element array 15 in which the light receiving elements 27 are linearly arranged in one line. The array direction of each of the arrays 14 and 15 is a direction orthogonal to the scanning direction 9. Therefore, when the infrared sensor 2 is scanned, the infrared detecting elements 18 and 2
The pair 3 outputs the same detection output with a certain delay. Pair of infrared detecting elements 19 and 24,..., Infrared detecting elements 22 and 27
The same applies to the pair.

The amplifier 5 includes amplifier sections 16-1 to 16-5 for amplifying the detection outputs of the infrared detecting elements 18 to 22 of the first infrared detecting element array 14, respectively. Amplifier sections 17-1 to 17- that amplify the detection outputs of the infrared detection elements 23 to 27, respectively.
It consists of five.

The arithmetic circuit 6 comprises a pair of infrared detecting elements 1
A computing unit 6-1 for receiving the outputs amplified by the amplifier units 16-1 and 17-1 of the 8, 8 and the infrared detecting element 1 forming a pair
A computing unit 6-2 for receiving outputs amplified by the amplifier units 16-2 and 17-2, and an infrared detecting element 2 forming a pair
A computing unit 6-3 receiving the outputs amplified by the 0 and 25 amplifier units 16-3 and 17-3, and a pair of infrared detecting elements 2
A computing unit 6-4 for receiving outputs amplified by the amplifier units 16-4 and 17-4, and an infrared detecting element 2 forming a pair
Operation units 6-5 for receiving outputs amplified by the amplifier units 16-5 and 17-5.
Operation outputs 7-1 to 7-5 can be obtained from -1 to 6-5, respectively.

In this embodiment, the infrared detector 8
Is linearly scanned in the scanning direction 9 so as to face the background 10 and the heat source 11, so that infrared radiation 13 radiated from the heat source 11 is incident on the infrared sensor 2 through the lens 1 of the infrared detector 8, Is amplified to a fixed level by the amplifier 5, and the result calculated by the calculation circuit 6 is output as a calculation output 7. Here, as described above, the infrared sensor 2 has the infrared detecting element arrays 14 and 15 in two rows, and the amplifier 5 includes the individual infrared detecting elements 18 to 22 and 23 to 27 of the infrared detecting element arrays 14 and 15. The amplifier circuit 16-1 to 16-5, 17-1 to 17-5 has a function of amplifying the output to a constant level, and the arithmetic circuit 6 amplifies the infrared detection elements forming a pair of the infrared detection elements 14 and 15. Calculation outputs 7-1 to 7- obtained by calculating (specifically, taking a difference) the subsequent outputs by the calculation units 6-1 to 6-5, respectively.
5, that is, a function of outputting a target infrared detection signal corresponding to the heat source 11.

In this case, two infrared detecting element arrays 1
4, 15 are scanned in parallel and simultaneously with respect to the heat source 11, causing a difference in detection time, that is, a phase delay of a scanning time determined by an interval between both arrays occurs, and a phase shift occurs in a detection signal waveform. Utilizing the occurrence, the target heat source 11 is detected by calculating the difference between the two outputs in the arithmetic circuit.

FIG. 3 shows a pair of infrared detecting elements 20 and 15 arranged in parallel with each other in the scanning direction 9 in the infrared detecting element arrays 14 and 15 constituting the infrared sensor 2 in parallel.
5A and 5B are schematic diagrams of an infrared detection signal and an operation result of the infrared detection element 25, and FIG.
0 and the infrared detection signals of the infrared detection element 25 are separately shown, and FIG.
This is the operation output after the operation by the (operation unit 6-3). If there is a target heat source having a temperature difference with respect to the background as shown in FIG. Then, as shown in FIG. 3B, a target heat source is detected at the point where it crosses the zero level by taking the difference between the detection signals.

FIG. 4 shows experimental results actually verifying the present invention. Two pairs of infrared detections obtained by scanning the heat source included in the background at a position 50 m away from the heat source are obtained. This is a calculation output obtained by taking the difference between the detection output of the element and the two. As described above, a desired operation output result can be obtained with a simple operation circuit configuration that only calculates the difference between the outputs of the infrared detecting elements forming a pair.

In the circuit shown in FIG.
-1 to 7-5 are obtained. For example, the operation output 7-
If any one of 1 to 7-5 indicates target detection as shown in FIG. 4, it can be determined that there is a target.

According to this embodiment, as is apparent from the results of the demonstration experiment, the two rows of infrared detecting element arrays 14 and 15 arranged in parallel are simultaneously scanned to utilize the detection time difference. This is extremely effective for detecting only the infrared radiation of the heat source contained in the background by signal emphasis.

Further, it is possible to realize an infrared detector irrespective of the response performance of the detection element. By performing a difference operation on the outputs 14 and 15 in the arithmetic circuit 6, detection equivalent to that of a high-speed response infrared detection element is possible.

Further, the arithmetic circuit after the detection can be realized with a simple configuration.

Although FIG. 2 experimentally shows an example in which each infrared detecting element array of the infrared sensor 2 has five elements, the number of each infrared detecting element array is arbitrary.

Although the embodiments of the present invention have been described above, it is obvious to those skilled in the art that the present invention is not limited to the embodiments and that various modifications and changes can be made within the scope of the claims. There will be.

[0023]

As described above, according to the scanning type infrared detector according to the present invention, a complicated signal processing circuit is not required, and the scanning type infrared detector is simple regardless of the response performance of the infrared detecting element used in the infrared sensor. The arithmetic circuit can effectively detect only the target infrared radiation from the background infrared radiation.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of a scanning infrared detector according to the present invention.

FIG. 2 is a block diagram of an infrared sensor and a subsequent circuit in the embodiment.

FIG. 3 is a schematic diagram of an infrared detection element output and a calculation output forming a pair of the infrared sensor obtained in the embodiment.

FIG. 4 is a signal waveform diagram showing a background obtained in an experiment, a detection result of infrared radiation from a heat source, and a calculation output.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 lens 2 infrared sensor 3 hole 4 housing 5 amplifier 6 arithmetic circuit 7 arithmetic output 8 infrared detection unit 9 scanning direction 10 background 11 heat source 12 infrared radiation from background 13 infrared radiation from heat source 14 first infrared detection element array 15 2 infrared detection element arrays 18 to 27 infrared detection elements

Claims (3)

[Claims] An infrared sensor that scans in a certain direction and detects infrared radiation from a heat source via a lens, and an arithmetic circuit that calculates an output signal from an amplifier that amplifies an output from the infrared sensor. A scanning infrared detector. 2. The infrared sensor, wherein a plurality of infrared detection element arrays in which infrared detection elements are linearly arranged are arranged in parallel, and only a plurality of infrared radiation from a heat source existing in infrared radiation from a background are transmitted to the infrared sensor. 2. The scanning infrared detector according to claim 1, wherein the signal is emphasized by an interval between the infrared detecting element arrays. 3. The infrared detecting element array is configured by arranging pyroelectric infrared detecting elements having relatively slow response characteristics, and calculating the difference between outputs of the plurality of infrared detecting element arrays in the arithmetic circuit. 3. The scanning infrared detector according to claim 2, wherein the response characteristic is speeded up by the following.