WO1993000576A1

WO1993000576A1 - Device for sensing thermal image

Info

Publication number: WO1993000576A1
Application number: PCT/JP1992/000549
Authority: WO
Inventors: Takashi Deguchi; Tatsuo Nakayama; Toshiaki Yagi; Ryoichi Takayama; Yoshihiro Tomita
Original assignee: Matsushita Electric Industrial Co., Ltd.
Priority date: 1991-06-24
Filing date: 1992-04-27
Publication date: 1993-01-07
Also published as: DE4292011T1; JPH04372828A; DE4292011C2; CA2090115A1; KR970003680B1; CA2090115C

Abstract

A device for sensing a thermal image which has a group of plural pyroelectric type heat sensing elements (5) arranged on a line, an optical system (6), a structure (7) for making the pyroelectric type heat sensing element group (5) and the optical system (6) in one body, and a rotary shaft (8) for rotating the structure (7). By this configuration, the system for obtaining a two-dimensional thermal image by using the pyroelectric type heat sensing element group arranged on the line in one-dimensional way can be realized with a simple configuration of a small size.

Description

Specification

Title of invention

Thermal image detector

Technical field

The present invention relates to radiation temperature detection and human body behavior detection based on thermal images, such as temperature distribution in living rooms in a home and human body behavior detection.

Background art

Therefore, non-contact methods for measuring temperature are based on a quantum infrared sensor and a thermal infrared sensor. Quantum infrared sensors have high sensitivity and a high response speed. About 0 0), not suitable for consumer use. (1) Thermal infrared sensors have relatively low sensitivity and low response speed, but do not require cooling, so they have been put to practical use in the consumer market.

Of the thermal infrared sensors, pyroelectric infrared sensors utilizing the pyroelectric effect are often used. Fig. 1 shows the embodiment. Fig. 1 (a) is a structural diagram of a pyroelectric infrared sensor unit used for human body detection. In the figure, 1 is a pyroelectric infrared sensor, and 2 is a Fresnel lens using polyethylene resin. The Fresnel lens 2 has a light distribution characteristic for the viewing angle.

The pyroelectric infrared sensor 1 has a differential change output characteristic, and outputs only when the incident temperature changes. When the human body crosses in front of the pyroelectric infrared sensor unit, due to the light distribution characteristics of the Fresnel lens 2, the radiation temperature of the human body appears in the pyroelectric infrared sensor 1 as a time change input that appears, disappears, appears, and disappears. Entered. Therefore, the output of the pyroelectric infrared sensor Is output in synchronization with.

As a means for obtaining a two-dimensional thermal image, a method of arranging a pyroelectric infrared sensor in two dimensions was also considered.

However, in the conventional example shown in Fig. 1, it is impossible to measure the force position and temperature distribution that can detect the presence of the human body, and the system configuration becomes complicated when the pyroelectric infrared sensor is arranged two-dimensionally. I have a problem

Also, when configuring a system that runs a group of pyroelectric heat detecting elements arranged linearly in one dimension, if the optical system is outside the group of pyroelectric heat detecting elements, the optical system will have a scanning range. There is a problem that the whole area must be focused on & it must be large, and even if it covers the entire scanning range, the optical axis shifts and the sensitivity of the entire visual field is not uniform. .

The present invention provides a system for detecting a thermal image with a relatively simple system configuration.

Disclosure of the invention

Therefore, the present invention has a plurality of pyroelectric heat detecting element groups one-dimensionally arranged on a linear axis and a rotation axis parallel or inclined at a fixed angle to the linear axis. A two-dimensional image is obtained by rotating the group of heat detection elements.

The present invention detects a thermal image with a relatively simple configuration by rotating a group of one-dimensionally arranged pyroelectric heat detection elements, and detects a temperature distribution in a detection area, a haze motion of a human body, and the like. . The present invention also provides a plurality of pyroelectric heat detection element groups arranged one-dimensionally on a linear axis, and an optical element integrated with the pyroelectric heat detection element group. A two-dimensional thermal image is obtained by rotating the pyroelectric heat detecting element group and the optical system, which are integrated with a system and a rotation axis parallel or inclined at a fixed angle to the linear axis, about the rotation axis. That is,

The present invention provides a two-dimensional thermal image detection system having a compact and simple configuration by miniaturizing an optical system by integrally rotating a pyroelectric heat detecting element group and an optical system which are linearly arranged one-dimensionally. Things.

BRIEF DESCRIPTION OF THE FIGURES

FIGS. 1 (a) and 1 (b) show the configuration of a conventional pyroelectric infrared unit for detecting a human body. FIGS. 2 (a) and 2 (b) show the configuration of one embodiment of the present invention. (A) and (b) are explanations of the mechanism for obtaining a thermal image. FIG. 4 is a configuration using a transmission type lens. FIG. 5 is a configuration using a reflection type lens. 図 FIG. 6 is another embodiment of the present invention. The schematic structure of the structure integrating the pyroelectric heat detection element group and the lens in the example ¾ Fig. 7 is a front view in the optical axis direction showing the positional relationship between the non-circular lens and the pyroelectric heat detection element group. Schematic configuration of a two-dimensional thermal imaging device using a grid-type fixed chopper ¾ Fig. 9 shows a schematic configuration of a two-dimensional thermal imaging device using a rotating chopper ¾ Fig. 10 shows a pyroelectric heat detection element group Schematic configuration of a two-dimensional thermal imager with a fixed chopper arranged between the lens and the lens Fig. 11 shows a movable chopper connected to the pyroelectric heat detection element group and the optical system. Schematic configuration of the two-dimensional thermal imaging device fixed to the axis of rotation ¾ Fig. 12 schematically shows the relationship between the visual field of the group of pyroelectric heat detection elements and the movable range of the chopper in a system in which the movable range of the chopper is limited. FIG. The best form for carrying out KIKI

An embodiment of the present invention will be described with reference to FIGS.

FIG. 2 is a configuration diagram of an embodiment of the present invention.

In FIG. 2, reference numerals 3a to 3e denote pyroelectric heat detection elements (hereinafter, referred to as elements), 4 denotes a pyroelectric heat detection element, and 5 denotes a rotation axis. Fig. 2 (a) shows that the rotating shaft 5 is parallel to the pyroelectric heat detecting element group 4, and Fig. 2 (b) shows that the rotating shaft 5 and the pyroelectric detecting element group 4 are at a fixed angle '0' only. This shows the case where the vehicle is inclined. Angle 0 is selected depending on the internal structure of the device to be installed and the setting of the detection viewing angle.

Next, a mechanism for obtaining a thermal image using the pyroelectric heat detection element group 4 will be described with reference to FIG. Fig. 3 (a) shows the stereoscopic viewing angle of the detected thermal image, and Fig. 3 (b) shows the detected thermal image.

The pyroelectric heat detection element group 4 has five elements, and is responsible for dividing the viewing angle into five in the vertical direction.

The pyroelectric-type mature detection element group 4 has a narrow viewing angle in the horizontal direction, and sequentially shifts the viewing angle in the ice flat direction with the rotation of the rotating shaft 5. The pyroelectric type detection element group 4 measures the temperature each time it is sequentially moved, so that a two-dimensional thermal image shown in FIG. 3 (b) is obtained.

In order to detect the position and behavior of the human body within the three-dimensional viewing angle detected here, the motion of the human body is usually said to be l to 2 Hz. Is valid.

The commonly used pyroelectric infrared sensor is a so-called bulk type using a pyroelectric thick film sintered body. The problem is that the response cannot keep up because the constant cannot be reduced. Therefore, by using a pyroelectric heat detecting element using a pyroelectric thin film of PbTiOS, etc., the response time can be reduced to about 1Z10 of the bulk type. By using the pyroelectric heat detecting element using the pyroelectric thin film to shorten the response time, the behavior of the human body can be detected with high accuracy. Furthermore, the use of a pyroelectric thin film can further reduce the size of the element.

In addition, when detecting temperature distribution and human body behavior in a living space, etc., the detection space generally has a wider viewing angle in the horizontal direction than in the vertical direction. The responsible viewing angle of the detection element group 4 can be reduced, and this can contribute to reducing the number of elements or improving accuracy.

Next, an embodiment of a thermal image detecting apparatus using an optical system will be described with reference to FIGS. 4 and 5. FIG.

Fig. 4 shows the case where a transmission lens is used, and Fig. 5 shows the case where a reflection lens is used. In any case, the pyroelectric heat detection element group 4 is a single optical system, and the divided viewing angles are assigned to the elements 3a to 3e. By using one optical system, the system can be downsized and the accuracy of the viewing angle of each element can be easily obtained.

If the transmission lens 6 shown in FIG. 4 is used, the optical system can be designed to be small. Furthermore, if a pyroelectric thin film is used for the element as described above, a very small system can be realized.

In the case of the transmission type lens 6, the material that transmits infrared light is very limited, whereas the reflection type lens 7 shown in Fig. 5 is used. Then, the infrared light reflecting material can be easily obtained by aluminum coating or the like, so that the optical system can be easily and inexpensively constructed.

Next, a two-dimensional thermal image detection apparatus in which the optical system is integrated with a pyroelectric detection element group will be described with reference to FIGS. 6 to 11. FIG.

In FIG. 6, reference numeral 15 denotes a pyroelectric heat detecting element group, and 15a to 15e denote pyroelectric heat detecting elements. Reference numeral 17 denotes a structure for integrating the pyroelectric heat detecting element group 15 with the lens 16, and the pyroelectric heat detecting element group 15 is arranged on the optical axis 30 of the lens 16.

'Fig. 7 shows the positional relationship between the lens and the pyroelectric heat detection element group as viewed from the front in the optical axis direction when a circular lens is used as an example of a non-circular lens. It is. Reference numeral 15 denotes a group of pyrothermal type heat detecting elements, and a non-circular lens 16a having a size necessary to cover the field of view of the group of pyroelectric type thermal detecting elements 15 is arranged in front and illustrated. The pyroelectric heat detection element group 15 and the lens 16 that are not fixed are fixed to a structure that integrates the pyroelectric heat detection element group 15 and the lens 16 to form a system similar to that shown in FIG. The broken line shows the size of the lens when a circular lens is used.

In FIG. 8, reference numeral 20a denotes a chopper fixed outside the pyroelectric heat detection element group 15 and the lens 16 and has a lattice shape. 30 is the optical axis of the lens.

In FIG. 9, 20 b is a rotary chopper installed outside the pyroelectric heat detecting element group 15 and the lens 16, and the rotating shaft 31 of the chopper is a pyroelectric heat detecting element group. It is fixed to the outside of 15 and lens 16.

In FIG. 10, reference numeral 20a denotes a pyroelectric heat detection element group 15 and This is a fixed chopper installed between hands 16.

In FIG. 11, the rotation axis 31 of the rotary chopper 20 b is fixed to the rotation axis 18 of the pyroelectric heat detection element group 15 and the lens 16.

In FIG. 12, reference numeral 25 denotes a movable chopper for opening and closing the window 25, and reference numeral 25 denotes a movable chopper that opens and closes the window 25. The heat detection element group 15 and the lens 16 are fixed to a structure in which they are integrated.

6 ^ 1 Overall configuration shown in FIG. 7 A two-dimensional thermal image is obtained by rotating around the rotation axis 18.

In FIG. 8, the structure 17 in which the pyroelectric heat detection element group 15 and the lens 16 are integrated is rotated about the rotation axis 18 so that the field of view of the chopper 20 a is fixed. Is scanned to obtain the differential output signal.

In FIG. 9, the chopper 20b rotates at a sufficient rotation speed independent of the rotation speed around the rotation shaft 18. In Fig. 10, the fixed-type chopper 20a is sandwiched between the pyroelectric heat-detecting element group 15 and the lens 16, and the pyroelectric heat-detecting element group 15 and the lens around the rotation axis 18 are sandwiched. 1 6 rotates together ¾o

In FIG. 11, the rotary chopper 20b rotates around the rotation axis 18 together with the pyroelectric heat detection element group 15 and the lens 16 to perform ^ chic pinking.

In FIG. 12, the chopper 20 d reciprocates to open and close the window 25. By integrating the pyroelectric heat detecting element group 15 and the lens 16 as shown in FIG. 6, the positional relationship between the lens 16 and the pyroelectric heat detecting element group 15 does not change during scanning. There is no shift and the entire field of view can be detected with uniform sensitivity. Also, the lens 16 can be made smaller than a non-integrated system, and the entire system can be downsized.

Further, by making the lens 16a non-circular as shown in FIG. 7, the lens 16a can be made small, and thus the system can be downsized.

Further, by sealing the space between the pyroelectric heat detection element group 15 and the lens 16 in Fig. 6, it is possible to reduce contamination due to dust and smoke in the air, and as a result, a stable long-term thermal image can be obtained. Will be able to do things.

As shown in Fig. 8, the chopper 20a is fixed to the outside of the pyroelectric heat detection element group 15 and the lens 16 so that only the rotation mechanism around the rotation axis 18 is used. A two-dimensional thermal image can be obtained with a simple system.

As shown in Fig. 9, a rotary chopper 20b is placed outside the pyroelectric heat detecting element group 15 and the lens 16 and this chopper-20b is rotated at a sufficient speed. Thus, a two-dimensional thermal image without blind spots can be obtained.

Further, in the configuration as shown in FIG. 10, the field of view of the pyroelectric heat detection element group 15 is narrowed down at the position of the chopper 20a, so that the chopper 20a can be downsized.

Furthermore, as shown in Fig. 11, the movable chopper 20 b is The chopper 20b can be reduced in size by employing a method of rotating together with the heat detection element group and the optical system, and the entire system can also be reduced in size.

By limiting the movable range of the movable chopper 20d to the field of view assigned to the pyroelectric heat detection element group 15 as shown in Fig. 12, the movable chopper 20d can be downsized. it can.

In FIG. 9, a force using a rotary chopper 2 Ob as a movable chopper is a movable chopper 20a having a lattice shape shown in FIG. 8, or an openable chopper shown in FIG. The same effect can be obtained even with 10 d.

Also, in FIG. 10, a similar effect can be obtained by using a movable chopper instead of the fixed chopper 20a.

In addition, a chopper that translates a grid-shaped chopper in place of the rotary chopper 20b in Fig. 11 or an openable chopper as shown in Fig. 11 is used as a pyroelectric heat detecting element. The same effect can be obtained when fixed to the rotation axis of the group and the optical system.

Industrial use shadow

According to the present invention, a thermal image can be detected with a relatively simple system configuration by rotating a group of pyroelectric heat detection elements arranged one-dimensionally.

In addition, the position S behavior of the human body can be accurately detected by setting the thermal image detection time due to rotation to within approximately 1 second 1.

Furthermore, by using a pyroelectric thin-film pyroelectric heat detection element group, the response speed of a thermal image can be improved, and the system can be downsized. In addition, by setting the rotation direction to the horizontal direction, it is possible to contribute to miniaturization of the system or improvement of the accuracy in a normal case.

In addition, by using one optical system, the size of the system can be reduced. The accuracy of the viewing angle of each element can be improved.

Further, by using a transmission lens, the size of the optical system can be further reduced.

In addition, an optical system can be easily and inexpensively constituted by a reflection type lens.

Further, according to the present invention, by using a method in which the pyroelectric heat detection element group and the optical system arranged one-dimensionally and the optical system are integrally rotated, the positional relationship between the pyroelectric heat detection element group and the optical system is scanned. There is no change in the optical axis, and the entire field of view can be detected with uniform sensitivity. In addition, the optical system can be downsized, and the entire system can be downsized.

Furthermore, by using a non-circular lens as the optical system, the system can be reduced in size at any time.

Furthermore, by using a closed structure between the pyroelectric heat detection element group and the lens, it is possible to reduce the reduction in detection sensitivity due to dirt and dust in the air, and to use the system stably for a long period of time. I can do it.

In addition, the configuration of the chopper can be simplified by using a fixed chopper.

The use of a movable chopper can eliminate blind spots in the obtained two-dimensional thermal image.

In addition, a chopper is placed between the pyroelectric heat detection element group and the optical system. As a result, the chopper only needs to cover the field of view narrowed by the lens, and the chopper can be downsized.

Further, by rotating the movable chopper together with the pyroelectric heat detection element group and the optical system, the chopper can be downsized and the system can be downsized.

Furthermore, by limiting the movable range of the movable chopper within the field of view assigned to the pyroelectric heat detection element group, the chopper can be downsized, and the entire system can be downsized.

Claims

Scope of request

1. A plurality of pyroelectric heat detection elements arranged one-dimensionally on a linear axis, and a rotation axis parallel to or inclined at a certain angle to the linear axis. Thermal image detection device that obtains a two-dimensional image by rotating an electric heat detection element group ¾>

2. The thermal image detection device according to claim 1, wherein the thermal image detection time due to rotation is approximately within 1 second.

3. The thermal image detection device according to claim 1, wherein a pyroelectric thin film is used for the pyroelectric heat detection element group.

4. The thermal image detection device according to claim 1, wherein the rotation direction is substantially horizontal.

5. The thermal image detection device according to claim 1, wherein the thermal image detection device has one optical system in which the viewing angle is assigned to each element of the pyroelectric heat detection element group.

6. The thermal image detection device So according to claim 5, wherein a transmission type optical system is used.

7. The thermal image detection device according to claim 5, wherein a reflection type optical system is used.

8. A plurality of pyroelectric heat detection element groups arranged one-dimensionally on a linear axis, an optical system integrated with the pyroelectric heat detection element group, and a parallel or fixed angle to the linear axis A thermal image detection device that obtains a two-dimensional image by rotating the pyroelectric heat detection element group and the optical system around a rotation axis that is only inclined at the center.

9. The thermal image detecting device according to claim 8, wherein a non-circular lens is used as the optical system.

10. The thermal image detecting device S according to claim 8, wherein the pyroelectric heat detecting element group and the optical dish are sealed.

11. The thermal image detecting device according to claim 8, further comprising a pyroelectric type detection element group and a chopper fixed outside the optical system.

12. The thermal image detection device S> according to claim 8, further comprising a pyroelectric heat detection element group and a movable chopper outside the optical system.

9. The thermal image detection device according to claim 8, further comprising a chopper between the pyroelectric heat detection element group and the optical system.

3.The thermal image detecting device according to claim 1, wherein a movable chopper is fixed to said rotating shaft.

15. The thermal image detection device a according to claim 14, wherein the movable range of the movable chopper is limited within a field of view assigned to the pyroelectric heat detection element group.