CA2090115C - Thermal image detection apparatus - Google Patents
Thermal image detection apparatusInfo
- Publication number
- CA2090115C CA2090115C CA002090115A CA2090115A CA2090115C CA 2090115 C CA2090115 C CA 2090115C CA 002090115 A CA002090115 A CA 002090115A CA 2090115 A CA2090115 A CA 2090115A CA 2090115 C CA2090115 C CA 2090115C
- Authority
- CA
- Canada
- Prior art keywords
- thermal
- detection element
- pyroelectric type
- thermal image
- detection apparatus
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 238000001514 detection method Methods 0.000 title claims abstract description 109
- 230000003287 optical effect Effects 0.000 claims abstract description 42
- 238000003491 array Methods 0.000 claims abstract description 9
- 230000000007 visual effect Effects 0.000 claims description 9
- 239000010409 thin film Substances 0.000 claims description 6
- 238000007789 sealing Methods 0.000 claims description 3
- 230000005855 radiation Effects 0.000 description 18
- 230000000694 effects Effects 0.000 description 5
- 230000035945 sensitivity Effects 0.000 description 5
- 238000001931 thermography Methods 0.000 description 4
- 238000001816 cooling Methods 0.000 description 2
- 239000000428 dust Substances 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 239000000779 smoke Substances 0.000 description 2
- 229910003781 PbTiO3 Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 239000010408 film Substances 0.000 description 1
- 238000010348 incorporation Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000012780 transparent material Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
- G01J5/02—Constructional details
- G01J5/08—Optical arrangements
- G01J5/0803—Arrangements for time-dependent attenuation of radiation signals
- G01J5/0805—Means for chopping radiation
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
- G01J5/10—Radiation pyrometry, e.g. infrared or optical thermometry using electric radiation detectors
- G01J5/34—Radiation pyrometry, e.g. infrared or optical thermometry using electric radiation detectors using capacitors, e.g. pyroelectric capacitors
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
- H04N23/20—Cameras or camera modules comprising electronic image sensors; Control thereof for generating image signals from infrared radiation only
- H04N23/23—Cameras or camera modules comprising electronic image sensors; Control thereof for generating image signals from infrared radiation only from thermal infrared radiation
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N3/00—Scanning details of television systems; Combination thereof with generation of supply voltages
- H04N3/02—Scanning details of television systems; Combination thereof with generation of supply voltages by optical-mechanical means only
- H04N3/08—Scanning details of television systems; Combination thereof with generation of supply voltages by optical-mechanical means only having a moving reflector
- H04N3/09—Scanning details of television systems; Combination thereof with generation of supply voltages by optical-mechanical means only having a moving reflector for electromagnetic radiation in the invisible region, e.g. infrared
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Spectroscopy & Molecular Physics (AREA)
- General Physics & Mathematics (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Health & Medical Sciences (AREA)
- Toxicology (AREA)
- Power Engineering (AREA)
- Electromagnetism (AREA)
- Radiation Pyrometers (AREA)
- Photometry And Measurement Of Optical Pulse Characteristics (AREA)
- Transforming Light Signals Into Electric Signals (AREA)
Abstract
It comprises a plurality of pyroelectric type of thermal detection element array 5 arranged in a line, an optical system 6, a structure 7 for incorporating the pyroelectric type of thermal detection element array 5 with the optical system 6, and a rotational axis 8 for rotating them. This structure provides a system for obtaining a two-dimensional thermal image with a plurality of pyroelectric type of thermal detection element arrays one-dimensionally arranged on a line with a small-sized and simple structure.
Description
SPECIFICATION
TITLE OF THE INVENTION
THERMAL IMAGE DETECTION APPARATUS
FIELD OF TECHNOLOGY
This invention relates to detection of radiation temperature and detection of motion of a human body by a thermal image of the temperature distribution of a living room in a home and the detection of motion of a human body.
BACKGROUND TECHNOLOGY
There have been found quantum type of infrared radiation sensors and thermal type of infrared radiation sensors as systems for measuring a temperature without contacting. The quantum type of infrared radiation sensor has a high sensibility and a quick response. However, it needs cooling (an extent of - 200~C), so that it is not suited for general use. On the other hand, though the thermal type of infrared radiation sensor has a relative low sensitivity and a slow response, it has been put to practical use in the market of the general use products because cooling is unnecessary.
Pyroelectric type of infrared radiation sensors which use the pyroelectric effect are used frequently in the thermal type of infrared radiation sensors. Fig. 1 shows its embodiment. Fig. l(a) is a structural drawing of pyroelectric type of infrared radiation sensor unit for 209011~
detecting a human body. In Fig. 1, numeral 1 is a pyroelectric type of infrared radiation sensor; numeral 2 is a Fresnel lens using a plyethlen resin. This Fresnel lens 2 is made to have a light distribution characteristic in the angle of visibility.
The pyroelectric type of infrared radiation sensor 1 has a differential change output characteristic and generates an output only when an incident temperature changes. When a human body goes across the front of the pyroelectric type of infrared radiation sensor, an input is inputted to the pyroelectric infrared radiation sensor 1, the input showing change with time such that a radiation temperature of the human body appears, disappears, appears, and disappears,---. Therefore, an output of the pyroelectric type of infrared radiation sensor is outputted in phase with this change with time.
Moreover, there has been proposed a system two-dimensionally arranging the pyroelectric type of infrared radiation sensors as a means for obtaining a two-dimensional thermal image.
However, though the prior art shown in Fig. 1 can detects the presence of the human body, it is impossible to measure a position and the temperature distribution.
Moreover, in a system in which the pyroelectric type of infrared radiation sensors are arranged two-dimensionally, ' -there are a problem that its system structure would be complicated.
Moreover, if a system is structured by a method that an array of pyroelectric type of thermal detection elements arranged one-dimensionally on a line is scanned, the size will be large because the optical system should cover the whole range of scanning area if the optical system is provided externally. Moreover, though the whole scanning area is covered, there is a problem that the sensitivities over the lo whole visual field becomes not uniform because the optical axis deviates.
This invention provides a system for detecting a thermal image with a relatively simple system structure.
DISCLOSURE OF THE INVENTION
This invention provides a two-dimensional image by a plurality of pyroelectric type of thermal detection element arrays one-dimensionally arranged in a linear axis and a rotational axis inclined by a predetermined angle wherein the pyroelectric type of thermal detection element array is rotated around the rotational axis.
This invention detects a temperature distribution within a detection area and detects a position, motion, and the like of a human body by detecting a thermal image with a relatively simple structure by rotating a pyroelectric type of thermal detection element array a~ranged one-dimensionally.
This invention provides a two-dimensional image by a plurality of pyroelectric type of thermal detection element arrays a~ranged one-dimensionally in a linear axis, an optical system incorporated with the pyroelectric type of thermal detection element arrays, and a rotational axis inclined by a predetermined angle wherein the pyroelectric type of thermal detection element arrays and the optical system are rotated around the rotational axis.
This invention provides a two-dimensional thermal 4 ~ 5 image detection system with a compact and simple structure by compacting an optical system by rotating a pyroelectric type of thermal detection element array one-dimensionally arranged in a line and the optical system in one.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 (a) and (b) is a structural drawing of a prior art pyroelectric type of infrared radiation unit for detecting a human body, Fig. 2 (a) and (b) is a structural drawing of an embodiment of this invention, Fig. 3 (a) and (b) is an explanatory drawing for illustrating a mechanism for obtaining a thermal image, Fig. 4 is a structural drawing where a transparent type of lens is used, Fig. 5 is a structural drawing where a reflective typ ~ .~
209011~i used, Fig. 6 is an approximate structural drawing showing a structure that a pyroelectric type of thermal detection element array is incorporated with a lens in one, Fig. 7 is a front view from an optical axis, showing a positional relation between a noncircular lens and the pyroelectric type of thermal detection element array, Fig. 8 is an approximate structural drawing of a two-dimensional thermal imaging apparatus using a stationary type of chopper having a grid shape, Fig. 9 is an approximate structural drawing of a two-dimensional thermal imaging apparatus using a rotational type of chopper, Fig. 10 is an approximate structural drawing of a two-dimensional thermal imaging apparatus where a stationary type of chopper is arranged between the pyroelectric type of thermal detection element array and a lens, Fig. 11 is an approximate structural drawing of a two-dimensional thermal imaging apparatus where a movable chopper is fixed to a rotational axis of the pyroelectric type of thermal detection element array and an optical system, Fig. 12 is an approximate structural drawing showing a relation between a visual field of the pyroelectric type of thermal detection element array and a movable range of the shopper in the system where the movable range of the chopper is limited.
PREFERRED EMBODIMENTS
Hereinbelow will be described embodiments of this 2~g~115 invention with Figs. 2 to 5.
Fig. 2 is a structural drawing of this invention.
In Fig. 2, numerals 3a to 3e are pyroelectric type of thermal detection elements (hereinafter referred to as element), numeral 4 is an pyroelectric type of thermal detection element array, and numeral 5 is a rotational axis.
Fig. 2 (a) shows a case where the rotational axis 5 is in parallel to the pyroelectric type of thermal detection element array 4 and Fig. 2 (b) shows a case where the rotational axis 5 is inclined from the pyroelectric type of thermal detection element array 4 by a predetermined angle ~.
The angle ~ is selected in accordance with an internal structure of apparatus built in and an angle of visibility of detection.
Hereinbelow will be described a mechanism for obtaining a thermal image with the pyroelectric type of thermal detection element array 4 using Fig. 3. Fig. 3 (a) shows a three-dimensional angle of visibility of a thermal image to be detected, and Fig. 3(b) shows a detection thermal image.
The pyroelectric type of thermal detection element array 4 has five elements. The vertical angle of visibility is divided into five angles which are assigned to the five elements respectively.
A horizontal angle of visibility of the pyroelectric 209011~
thermal detection element array 4 is designed to be a narrow angle and is successively moved with the rotation of the rotational axis 5. Measurement of temperatures by the pyroelectric type of thermal detection element array 4 at every successive movement provides a two-dimensional thermal image as shown in Fig. 3 (b).
Here, it is effective that a detection interval of the thermal image by rotation is approximately equal or less than one second for detecting a position and motion of a human body to be detected within a three-dimensional angle of visibility because it is generally said that a motion of a human body is from one to two Hz.
Moreover, the pyroelectric type of infrared radiation sensor generally used is of a so-called bulk type which uses a sintered body of a pyroelectric thick film.
The bulk type has a problem that its response is slow because its thermal time constant cannot be made small.
Thus, it is possible to decrease the response time to a degree of 1/10 of the bulk type one by using a pyroelectric thin film made of PbTiO3, etc. Use of pyroelectric type of thermal detection elements using this pyroelectric thin films provides decreasing of the response time to detect the motion of a human body with a high accuracy. Further, it is possible to further miniaturize the element by the use of the pyroelectric thin film.
209011~
Moreover, if a temperature distribution of a living room space or the like and the motion of a human body are detected, generally there is rather common cases that the angle of visibility of a detection space in the horizontal direction is broader than that in the vertical direction.
In this case, the angles of visibility of the pyroelectric type of thermal detection element array 4 can be small by setting the rotational direction to the horizontal direction, so that the number of the elements vanishes or its accuracy is improved.
Hereinbelow will be described embodiments of thermal image detection apparatus using optical systems with reference to Figs. 4 and 5.
Fig. 4 shows the case where a transparent type of lens is used. Fig. 5 shows the case where a reflective type of lens is used. In each of cases, one system of optical system for the pyroelectric type of thermal detection element array 4. Each of divided angles is assigned to each of elements 3a to 3e. The system is miniaturized and angles of visibility assigned to respective elements can be obtained easily because the number of the optical system is one.
It is easy to design the optical system with a small dimension using a transparent type of lens 6 shown in Fig.
4. Moreover, it is possible to realize a subminiature system by employing the pyroelectric thin film for the elements as mentioned above.
Moreover, though in the case of the transparent type of lens 6, a transparent material of infrared ray is limited considerably, the use of the reflective lens 7 shown in Fig. 5 provides the optical system easily and at a low cost because an infrared-radiation-reflective material can be obtained with aluminum coating and the like.
Hereinbelow will be described two-dimensional thermal image detection apparatus where an optical system is incorporated with a pyroelectric type of thermal detection element array with reference to Figs. 6 to 11.
In Fig. 6, numeral 15 is a pyroelectric type of thermal detection array, and numeral 15a to 15e are pyroelectric type of thermal detection elements. Numeral 17 is a structure for incorporating the pyroelectric type of thermal detection element array 15 with a lens 16. The pyroelectric type of thermal detection element array 15 is arranged in an optical axis 30 of the lens 16.
Fig. 7 shows an example of a noncircular lens where a lens obtained partially cutting a circular lens, that is, Fig. 7 shows a positional relation between the lens and the pyroelectric type of thermal detection element array viewed from the front of the direction of the optical axis.
Numeral 15 is a pyroelectric type of thermal detection 209011~
element array. The noncircular lens 16a having a dimension necessary for covering the angle of visibility of the pyroelectric type of thermal detection element array 15, is arranged in front of the pyroelectric type of thermal detection element array 15. This system is similar to the system as shown in Fig. 6 by fixing them by a not-shown structure for incorporating the pyroelectric type of thermal detection element array 15 with the lens 16. The chain line shows an outline if a circular lens is used.
In Fig. 8, numeral 20a is a chopper fixed outside the pyroelectric type of thermal detection element array 15 and the lens 16 and has a grid shape. Numeral 30 is an optical axis of the lens.
In Fig. 9, numeral 20b is a rotational chopper arranged outside the pyroelectric type of thermal detection element array 15 and the lens 16. A rotational axis 31 of the chopper is fixed to an external of the pyroelectric type of thermal detection element array 15 and the lens 16.
In Fig. 10, numeral 20a is a stationary chopper arranged between the pyroelectric type of thermal detection element array 15 and the lens 16.
In Fig. 11, a rotational axis 31 of the rotational chopper 20b is fixed to a rotational axis 18 of the pyroelectric type of thermal detection element array 15 and 2~ the lens 16.
209011~
In Fig. 12, numeral 25 is a window defining a visual field of the pyroelectric type of thermal detection element array 15. Numeral 20d is a movable chopper for opening and shutting the window 25. They are fixed a not-shown structure for incorporating the pyroelectric type of thermal detection element array 15 with the lens 16.
Rotations of the whole structures shown in Figs. 6 and 7 around the rotational axis 18 provide two-dimensional thermal images.
In Fig. 8, the rotation of the structure 17 for incorporating the pyroelectric type of thermal detection element array 15 with the lens 16 causes its visual filed to scan the stationary chopper 20a, so that a differential output signal is provided.
Moreover, in Fig. 9, the chopper 20b rotates at a sufficient rotational speed independently from the rotational speed of the rational axis 18.
In Fig. 10, the pyroelectric type of thermal detection element array 15 and the lens 16 are rotated in one with the stationary chopper 20a sandwiched between the pyroelectric thermal detection elements array 15 and the lens 16.
In Fig. 11, the rotational chopper 20b effects the chopping with it rotated around the rotational axis 18 together with the pyroelectric type of thermal detection 209011~
element array 15 and the lens 16.
In Fig. 12, the chopper 20d opens and shuts the window 25 by its reciprocating motion.
The detection with a uniform sensitivity over the visual field is obtained by incorporating the pyroelectric type of thermal detection element array 15 with the lens 16 as shown in Fig. 6 because the positional relation between the lens 16 and the pyroelectric type of thermal detection element array 15 does not change during the scanning, so that there is no deviation of the optical axis. The whole system can be more miniaturized than a system without incorporation because the lens 16 is made small.
Moreover, the system can be miniaturized by making the lens 16a noncircular as shown in Fig. 7 to decrease the size of th lens 16a.
Further, the thermal image can be obtained stable over a long period by sealing the space between the pyroelectric thermal detection element array 15 and the lens 6 as shown in Fig. 6 because this sealing can reduce dirt due to dust or smoke in the air.
Moreover, the two-dimensional thermal image can be obtained with a simple system comprising the rotating mechanism having the center of the rotational axis 18 by the chopper 20a which is fixed outside the pyroelectric type of thermal detection element array 15a and the lens 16 as shown in Fig. 8.
Moreover, the two-dimensional thermal image without a dead angle can be obtained by the rotational type of chopper 20b arranged outside the pyroelectric type of thermal detection element array 15 and the lens 16 as shown in ~ig. 9 and rotated at a sufficient rotational speed.
Moreover, the chopper 20a can be miniaturized with the structure as shown in Fig. 10 because at the position of the chopper 20a, the visual field of the pyroelectric type of thermal detection element array 15 is stopped down small.
Further, the chopper 20b can be miniaturized by the system where the movable chopper 20b is rotated with the pyroelectric type of thermal detection element array and the optical system as shown in Fig. 11, so that the whole system is miniaturized.
Moreover, the movable chopper 20d can be miniaturized by limiting the movable range of the movable chopper 20d within the visual field assigned to the pyroelectric type of thermal detection element array 15.
In Fig. 9, the rotational chopper 20b is used as a moveable chopper. However, a similar effect can be obtained with the movable chopper 20a having a grid shape as shown in Fig. 8 or with the opening and shutting type of chopper 20d shown in Fig. 12.
20901i5 Moreover, in Fig. 10, a similar effect can be obtained with a movable chopper in place of the stationary chopper 20a.
Moreover, in place with the rotational chopper 20b, a similar effect can be obtained with a chopper employing a method where a grid chopper is subjected to a translational motion or by that the opening-and-shutting type of chopper as shown in Fig. 11 is fixed to the rotational axis of the pyroelectric type of thermal detection element array and the optical system.
INDUSTRIAL APPLICATION
According to this invention, a thermal image can be detected with a relatively simple system structure by rotating the pyroelectric type of thermal detection element array arranged one-dimensionally.
Moreover, the position and motion of a human body can be detected with a high accuracy by setting the detection interval of a thermal image by rotation within approximately one second.
Further, the use of pyroelectric type of thermal detection element array using the pyroelectric thin film provides the improvement in the response to the thermal image and miniaturization of the system.
Moreover, setting the rotational direction to horizontal contributes the miniaturization of the system or 209011~-improvement in accuracy generally.
Moreover, setting the number of the optical systems to one provides miniaturization of the system and improvement in the accuracy of angles of visibility assigning to respective elements.
The use of the transparent type of lens provides miniaturization of the optical system.
Moreover, the reflective type of lens the optical system provides the structure easily at a low cost.
Moreover, according to this invention, the detection with a uniform sensitivity over the angle of visibility is obtained by a system where the pyroelectric type of thermal detection element array and the optical system are rotated in one because the positional relation between the optical system and the pyroelectric thermal detection element array does not change during the scanning, so that there is no deviation of the optical axis. The optical system can be miniaturized, so that whole system can be miniaturized.
Further, the system can be further miniaturized by use of a noncircular lens for the optical system.
Further, the decrease in the detection sensitivity due to dirt by dust or smoke or the like in the air is reduced by the structure where the space between the pyroelectric type of thermal detection element array and the lens is sealed.
~09011~
Moreover, the structure of the chopper portion can be simple using a stationary chopper.
Moreover, a dead angle of the two-dimensional thermal image obtained can be removed by use of a movable chopper.
Moreover, a chopper can be miniaturized by arranging the chopper between the pyroelectric type of detection element array and the optical system because the chopper should cover only angle of visibility stopped down by the lens.
Further, the chopper can be miniaturized by rotating the movable chopper with the pyroelectric type of thermal detection element array and the optical system, so that the system can be miniaturized.
Further, the chopper can be miniaturized by limiting the movable range of the movable chopper within the visual filed assigned to the pyroelectric type of thermal detection element array, so that the whole system can be miniaturized.
TITLE OF THE INVENTION
THERMAL IMAGE DETECTION APPARATUS
FIELD OF TECHNOLOGY
This invention relates to detection of radiation temperature and detection of motion of a human body by a thermal image of the temperature distribution of a living room in a home and the detection of motion of a human body.
BACKGROUND TECHNOLOGY
There have been found quantum type of infrared radiation sensors and thermal type of infrared radiation sensors as systems for measuring a temperature without contacting. The quantum type of infrared radiation sensor has a high sensibility and a quick response. However, it needs cooling (an extent of - 200~C), so that it is not suited for general use. On the other hand, though the thermal type of infrared radiation sensor has a relative low sensitivity and a slow response, it has been put to practical use in the market of the general use products because cooling is unnecessary.
Pyroelectric type of infrared radiation sensors which use the pyroelectric effect are used frequently in the thermal type of infrared radiation sensors. Fig. 1 shows its embodiment. Fig. l(a) is a structural drawing of pyroelectric type of infrared radiation sensor unit for 209011~
detecting a human body. In Fig. 1, numeral 1 is a pyroelectric type of infrared radiation sensor; numeral 2 is a Fresnel lens using a plyethlen resin. This Fresnel lens 2 is made to have a light distribution characteristic in the angle of visibility.
The pyroelectric type of infrared radiation sensor 1 has a differential change output characteristic and generates an output only when an incident temperature changes. When a human body goes across the front of the pyroelectric type of infrared radiation sensor, an input is inputted to the pyroelectric infrared radiation sensor 1, the input showing change with time such that a radiation temperature of the human body appears, disappears, appears, and disappears,---. Therefore, an output of the pyroelectric type of infrared radiation sensor is outputted in phase with this change with time.
Moreover, there has been proposed a system two-dimensionally arranging the pyroelectric type of infrared radiation sensors as a means for obtaining a two-dimensional thermal image.
However, though the prior art shown in Fig. 1 can detects the presence of the human body, it is impossible to measure a position and the temperature distribution.
Moreover, in a system in which the pyroelectric type of infrared radiation sensors are arranged two-dimensionally, ' -there are a problem that its system structure would be complicated.
Moreover, if a system is structured by a method that an array of pyroelectric type of thermal detection elements arranged one-dimensionally on a line is scanned, the size will be large because the optical system should cover the whole range of scanning area if the optical system is provided externally. Moreover, though the whole scanning area is covered, there is a problem that the sensitivities over the lo whole visual field becomes not uniform because the optical axis deviates.
This invention provides a system for detecting a thermal image with a relatively simple system structure.
DISCLOSURE OF THE INVENTION
This invention provides a two-dimensional image by a plurality of pyroelectric type of thermal detection element arrays one-dimensionally arranged in a linear axis and a rotational axis inclined by a predetermined angle wherein the pyroelectric type of thermal detection element array is rotated around the rotational axis.
This invention detects a temperature distribution within a detection area and detects a position, motion, and the like of a human body by detecting a thermal image with a relatively simple structure by rotating a pyroelectric type of thermal detection element array a~ranged one-dimensionally.
This invention provides a two-dimensional image by a plurality of pyroelectric type of thermal detection element arrays a~ranged one-dimensionally in a linear axis, an optical system incorporated with the pyroelectric type of thermal detection element arrays, and a rotational axis inclined by a predetermined angle wherein the pyroelectric type of thermal detection element arrays and the optical system are rotated around the rotational axis.
This invention provides a two-dimensional thermal 4 ~ 5 image detection system with a compact and simple structure by compacting an optical system by rotating a pyroelectric type of thermal detection element array one-dimensionally arranged in a line and the optical system in one.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 (a) and (b) is a structural drawing of a prior art pyroelectric type of infrared radiation unit for detecting a human body, Fig. 2 (a) and (b) is a structural drawing of an embodiment of this invention, Fig. 3 (a) and (b) is an explanatory drawing for illustrating a mechanism for obtaining a thermal image, Fig. 4 is a structural drawing where a transparent type of lens is used, Fig. 5 is a structural drawing where a reflective typ ~ .~
209011~i used, Fig. 6 is an approximate structural drawing showing a structure that a pyroelectric type of thermal detection element array is incorporated with a lens in one, Fig. 7 is a front view from an optical axis, showing a positional relation between a noncircular lens and the pyroelectric type of thermal detection element array, Fig. 8 is an approximate structural drawing of a two-dimensional thermal imaging apparatus using a stationary type of chopper having a grid shape, Fig. 9 is an approximate structural drawing of a two-dimensional thermal imaging apparatus using a rotational type of chopper, Fig. 10 is an approximate structural drawing of a two-dimensional thermal imaging apparatus where a stationary type of chopper is arranged between the pyroelectric type of thermal detection element array and a lens, Fig. 11 is an approximate structural drawing of a two-dimensional thermal imaging apparatus where a movable chopper is fixed to a rotational axis of the pyroelectric type of thermal detection element array and an optical system, Fig. 12 is an approximate structural drawing showing a relation between a visual field of the pyroelectric type of thermal detection element array and a movable range of the shopper in the system where the movable range of the chopper is limited.
PREFERRED EMBODIMENTS
Hereinbelow will be described embodiments of this 2~g~115 invention with Figs. 2 to 5.
Fig. 2 is a structural drawing of this invention.
In Fig. 2, numerals 3a to 3e are pyroelectric type of thermal detection elements (hereinafter referred to as element), numeral 4 is an pyroelectric type of thermal detection element array, and numeral 5 is a rotational axis.
Fig. 2 (a) shows a case where the rotational axis 5 is in parallel to the pyroelectric type of thermal detection element array 4 and Fig. 2 (b) shows a case where the rotational axis 5 is inclined from the pyroelectric type of thermal detection element array 4 by a predetermined angle ~.
The angle ~ is selected in accordance with an internal structure of apparatus built in and an angle of visibility of detection.
Hereinbelow will be described a mechanism for obtaining a thermal image with the pyroelectric type of thermal detection element array 4 using Fig. 3. Fig. 3 (a) shows a three-dimensional angle of visibility of a thermal image to be detected, and Fig. 3(b) shows a detection thermal image.
The pyroelectric type of thermal detection element array 4 has five elements. The vertical angle of visibility is divided into five angles which are assigned to the five elements respectively.
A horizontal angle of visibility of the pyroelectric 209011~
thermal detection element array 4 is designed to be a narrow angle and is successively moved with the rotation of the rotational axis 5. Measurement of temperatures by the pyroelectric type of thermal detection element array 4 at every successive movement provides a two-dimensional thermal image as shown in Fig. 3 (b).
Here, it is effective that a detection interval of the thermal image by rotation is approximately equal or less than one second for detecting a position and motion of a human body to be detected within a three-dimensional angle of visibility because it is generally said that a motion of a human body is from one to two Hz.
Moreover, the pyroelectric type of infrared radiation sensor generally used is of a so-called bulk type which uses a sintered body of a pyroelectric thick film.
The bulk type has a problem that its response is slow because its thermal time constant cannot be made small.
Thus, it is possible to decrease the response time to a degree of 1/10 of the bulk type one by using a pyroelectric thin film made of PbTiO3, etc. Use of pyroelectric type of thermal detection elements using this pyroelectric thin films provides decreasing of the response time to detect the motion of a human body with a high accuracy. Further, it is possible to further miniaturize the element by the use of the pyroelectric thin film.
209011~
Moreover, if a temperature distribution of a living room space or the like and the motion of a human body are detected, generally there is rather common cases that the angle of visibility of a detection space in the horizontal direction is broader than that in the vertical direction.
In this case, the angles of visibility of the pyroelectric type of thermal detection element array 4 can be small by setting the rotational direction to the horizontal direction, so that the number of the elements vanishes or its accuracy is improved.
Hereinbelow will be described embodiments of thermal image detection apparatus using optical systems with reference to Figs. 4 and 5.
Fig. 4 shows the case where a transparent type of lens is used. Fig. 5 shows the case where a reflective type of lens is used. In each of cases, one system of optical system for the pyroelectric type of thermal detection element array 4. Each of divided angles is assigned to each of elements 3a to 3e. The system is miniaturized and angles of visibility assigned to respective elements can be obtained easily because the number of the optical system is one.
It is easy to design the optical system with a small dimension using a transparent type of lens 6 shown in Fig.
4. Moreover, it is possible to realize a subminiature system by employing the pyroelectric thin film for the elements as mentioned above.
Moreover, though in the case of the transparent type of lens 6, a transparent material of infrared ray is limited considerably, the use of the reflective lens 7 shown in Fig. 5 provides the optical system easily and at a low cost because an infrared-radiation-reflective material can be obtained with aluminum coating and the like.
Hereinbelow will be described two-dimensional thermal image detection apparatus where an optical system is incorporated with a pyroelectric type of thermal detection element array with reference to Figs. 6 to 11.
In Fig. 6, numeral 15 is a pyroelectric type of thermal detection array, and numeral 15a to 15e are pyroelectric type of thermal detection elements. Numeral 17 is a structure for incorporating the pyroelectric type of thermal detection element array 15 with a lens 16. The pyroelectric type of thermal detection element array 15 is arranged in an optical axis 30 of the lens 16.
Fig. 7 shows an example of a noncircular lens where a lens obtained partially cutting a circular lens, that is, Fig. 7 shows a positional relation between the lens and the pyroelectric type of thermal detection element array viewed from the front of the direction of the optical axis.
Numeral 15 is a pyroelectric type of thermal detection 209011~
element array. The noncircular lens 16a having a dimension necessary for covering the angle of visibility of the pyroelectric type of thermal detection element array 15, is arranged in front of the pyroelectric type of thermal detection element array 15. This system is similar to the system as shown in Fig. 6 by fixing them by a not-shown structure for incorporating the pyroelectric type of thermal detection element array 15 with the lens 16. The chain line shows an outline if a circular lens is used.
In Fig. 8, numeral 20a is a chopper fixed outside the pyroelectric type of thermal detection element array 15 and the lens 16 and has a grid shape. Numeral 30 is an optical axis of the lens.
In Fig. 9, numeral 20b is a rotational chopper arranged outside the pyroelectric type of thermal detection element array 15 and the lens 16. A rotational axis 31 of the chopper is fixed to an external of the pyroelectric type of thermal detection element array 15 and the lens 16.
In Fig. 10, numeral 20a is a stationary chopper arranged between the pyroelectric type of thermal detection element array 15 and the lens 16.
In Fig. 11, a rotational axis 31 of the rotational chopper 20b is fixed to a rotational axis 18 of the pyroelectric type of thermal detection element array 15 and 2~ the lens 16.
209011~
In Fig. 12, numeral 25 is a window defining a visual field of the pyroelectric type of thermal detection element array 15. Numeral 20d is a movable chopper for opening and shutting the window 25. They are fixed a not-shown structure for incorporating the pyroelectric type of thermal detection element array 15 with the lens 16.
Rotations of the whole structures shown in Figs. 6 and 7 around the rotational axis 18 provide two-dimensional thermal images.
In Fig. 8, the rotation of the structure 17 for incorporating the pyroelectric type of thermal detection element array 15 with the lens 16 causes its visual filed to scan the stationary chopper 20a, so that a differential output signal is provided.
Moreover, in Fig. 9, the chopper 20b rotates at a sufficient rotational speed independently from the rotational speed of the rational axis 18.
In Fig. 10, the pyroelectric type of thermal detection element array 15 and the lens 16 are rotated in one with the stationary chopper 20a sandwiched between the pyroelectric thermal detection elements array 15 and the lens 16.
In Fig. 11, the rotational chopper 20b effects the chopping with it rotated around the rotational axis 18 together with the pyroelectric type of thermal detection 209011~
element array 15 and the lens 16.
In Fig. 12, the chopper 20d opens and shuts the window 25 by its reciprocating motion.
The detection with a uniform sensitivity over the visual field is obtained by incorporating the pyroelectric type of thermal detection element array 15 with the lens 16 as shown in Fig. 6 because the positional relation between the lens 16 and the pyroelectric type of thermal detection element array 15 does not change during the scanning, so that there is no deviation of the optical axis. The whole system can be more miniaturized than a system without incorporation because the lens 16 is made small.
Moreover, the system can be miniaturized by making the lens 16a noncircular as shown in Fig. 7 to decrease the size of th lens 16a.
Further, the thermal image can be obtained stable over a long period by sealing the space between the pyroelectric thermal detection element array 15 and the lens 6 as shown in Fig. 6 because this sealing can reduce dirt due to dust or smoke in the air.
Moreover, the two-dimensional thermal image can be obtained with a simple system comprising the rotating mechanism having the center of the rotational axis 18 by the chopper 20a which is fixed outside the pyroelectric type of thermal detection element array 15a and the lens 16 as shown in Fig. 8.
Moreover, the two-dimensional thermal image without a dead angle can be obtained by the rotational type of chopper 20b arranged outside the pyroelectric type of thermal detection element array 15 and the lens 16 as shown in ~ig. 9 and rotated at a sufficient rotational speed.
Moreover, the chopper 20a can be miniaturized with the structure as shown in Fig. 10 because at the position of the chopper 20a, the visual field of the pyroelectric type of thermal detection element array 15 is stopped down small.
Further, the chopper 20b can be miniaturized by the system where the movable chopper 20b is rotated with the pyroelectric type of thermal detection element array and the optical system as shown in Fig. 11, so that the whole system is miniaturized.
Moreover, the movable chopper 20d can be miniaturized by limiting the movable range of the movable chopper 20d within the visual field assigned to the pyroelectric type of thermal detection element array 15.
In Fig. 9, the rotational chopper 20b is used as a moveable chopper. However, a similar effect can be obtained with the movable chopper 20a having a grid shape as shown in Fig. 8 or with the opening and shutting type of chopper 20d shown in Fig. 12.
20901i5 Moreover, in Fig. 10, a similar effect can be obtained with a movable chopper in place of the stationary chopper 20a.
Moreover, in place with the rotational chopper 20b, a similar effect can be obtained with a chopper employing a method where a grid chopper is subjected to a translational motion or by that the opening-and-shutting type of chopper as shown in Fig. 11 is fixed to the rotational axis of the pyroelectric type of thermal detection element array and the optical system.
INDUSTRIAL APPLICATION
According to this invention, a thermal image can be detected with a relatively simple system structure by rotating the pyroelectric type of thermal detection element array arranged one-dimensionally.
Moreover, the position and motion of a human body can be detected with a high accuracy by setting the detection interval of a thermal image by rotation within approximately one second.
Further, the use of pyroelectric type of thermal detection element array using the pyroelectric thin film provides the improvement in the response to the thermal image and miniaturization of the system.
Moreover, setting the rotational direction to horizontal contributes the miniaturization of the system or 209011~-improvement in accuracy generally.
Moreover, setting the number of the optical systems to one provides miniaturization of the system and improvement in the accuracy of angles of visibility assigning to respective elements.
The use of the transparent type of lens provides miniaturization of the optical system.
Moreover, the reflective type of lens the optical system provides the structure easily at a low cost.
Moreover, according to this invention, the detection with a uniform sensitivity over the angle of visibility is obtained by a system where the pyroelectric type of thermal detection element array and the optical system are rotated in one because the positional relation between the optical system and the pyroelectric thermal detection element array does not change during the scanning, so that there is no deviation of the optical axis. The optical system can be miniaturized, so that whole system can be miniaturized.
Further, the system can be further miniaturized by use of a noncircular lens for the optical system.
Further, the decrease in the detection sensitivity due to dirt by dust or smoke or the like in the air is reduced by the structure where the space between the pyroelectric type of thermal detection element array and the lens is sealed.
~09011~
Moreover, the structure of the chopper portion can be simple using a stationary chopper.
Moreover, a dead angle of the two-dimensional thermal image obtained can be removed by use of a movable chopper.
Moreover, a chopper can be miniaturized by arranging the chopper between the pyroelectric type of detection element array and the optical system because the chopper should cover only angle of visibility stopped down by the lens.
Further, the chopper can be miniaturized by rotating the movable chopper with the pyroelectric type of thermal detection element array and the optical system, so that the system can be miniaturized.
Further, the chopper can be miniaturized by limiting the movable range of the movable chopper within the visual filed assigned to the pyroelectric type of thermal detection element array, so that the whole system can be miniaturized.
Claims (15)
1. A thermal image detection apparatus comprising a plurality of pyroelectric type of thermal detection element arrays one-dimensionally arranged on a line and a rotational axis inclined by a predetermined angle wherein said pyroelectric type of thermal detection element arrays are rotated around said rotational axis.
2. A thermal image detection apparatus as claimed in claim 1, wherein an interval for detecting a thermal image by the rotation is equal or less than approximately one second.
3. A thermal image detection apparatus as claimed in claim 1, wherein the pyroelectric type of thermal detection element array comprises pyroelectric thin films.
4. A thermal image detection apparatus as claimed in claim 1, wherein a rotational direction is substantially horizontal.
5. A thermal image detection apparatus as claimed in claim 1, further comprising one optical system which assigns independent angles of visibility to elements of the pyroelectric type of thermal detection element array respectively.
6. A thermal image detection apparatus as claimed in claim 5, wherein a transparent type optical system is used.
7. A thermal image detection apparatus as claimed in claim 5, wherein a reflective type of optical system is used.
8. A thermal image detection apparatus for obtaining a two-dimensional image, comprising a plurality of pyroelectric type of thermal detection element arrays one-dimensionally arranged on a line, an optical system incorporated with said pyroelectric type of thermal detection element array, wherein said pyroelectric type of thermal detection element arrays are rotated around a rotational axis inclined from the line by a predetermined angle.
9. A thermal image detection apparatus as claimed in claim 8, wherein the optical system comprises a noncircular lens.
10. A thermal image detection apparatus as claimed in claim 8, further comprising a structure for sealing a space between the pyroelectric type of thermal detection element array and said optical system.
11. A thermal image detection apparatus as claimed in claim 8, further comprising a chopper fixed outside the pyroelectric type of thermal detection element and said optical system.
12. A thermal image detection apparatus as claimed in claim 8, further comprising a movable chopper outside the pyroelectric type of thermal detection element and said optical system.
13. A thermal image detection apparatus as claimed in claim 8, further comprising a chopper provided between the pyroelectric type of thermal detection element and said optical system.
14. A thermal image detection apparatus as claimed in claim 12, wherein the movable chopper is fixed to said rotational axis.
15. A thermal image detection apparatus as claimed in claim 14, wherein a movable range of the movable chopper is limited within the visual filed assigned to said pyroelectric type of thermal detection element array.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3151415A JPH04372828A (en) | 1991-06-24 | 1991-06-24 | Thermal-image detecting apparatus |
| JP3-151415 | 1991-06-24 | ||
| PCT/JP1992/000549 WO1993000576A1 (en) | 1991-06-24 | 1992-04-27 | Device for sensing thermal image |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2090115A1 CA2090115A1 (en) | 1992-12-25 |
| CA2090115C true CA2090115C (en) | 1999-06-22 |
Family
ID=15518117
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002090115A Expired - Fee Related CA2090115C (en) | 1991-06-24 | 1992-04-27 | Thermal image detection apparatus |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPH04372828A (en) |
| KR (1) | KR970003680B1 (en) |
| CA (1) | CA2090115C (en) |
| DE (2) | DE4292011T1 (en) |
| WO (1) | WO1993000576A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5858531A (en) * | 1996-10-24 | 1999-01-12 | Bio Syntech | Method for preparation of polymer microparticles free of organic solvent traces |
| CN104662397B (en) * | 2013-07-31 | 2017-06-27 | 松下电器（美国）知识产权公司 | Sensor cluster |
| EP3688662A1 (en) | 2017-09-27 | 2020-08-05 | 3M Innovative Properties Company | Personal protective equipment management system using optical patterns for equipment and safety monitoring |
Family Cites Families (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4121454A (en) * | 1976-12-03 | 1978-10-24 | Monitek, Inc. | Clamp on electromagnetic flow transducer |
| JPS55158524A (en) * | 1979-05-28 | 1980-12-10 | Kureha Chem Ind Co Ltd | Pyroelectric image sensor |
| JPS5620479A (en) * | 1979-07-30 | 1981-02-26 | Sofuia Kk | Pinball machine |
| JPS57124981A (en) * | 1981-01-27 | 1982-08-04 | Mitsubishi Electric Corp | Monitor for infrared ray |
| JPS57168045A (en) * | 1981-04-08 | 1982-10-16 | Toyota Motor Corp | Air-fuel-ratio control device for internal combustion engine |
| JPH073362B2 (en) * | 1984-06-14 | 1995-01-18 | 株式会社村田製作所 | One-dimensional pyroelectric sensor array |
| JPS61173124A (en) * | 1985-01-28 | 1986-08-04 | Matsushita Electric Ind Co Ltd | Pyroelectric type thermal image device |
| JPS61186826A (en) * | 1985-02-14 | 1986-08-20 | Matsushita Electric Ind Co Ltd | Thermal imaging device |
| JPS61290330A (en) * | 1985-06-18 | 1986-12-20 | Matsushita Electric Ind Co Ltd | Pyroelectric type heat image apparatus |
| DE3616374A1 (en) * | 1986-05-15 | 1987-11-19 | Siemens Ag | PYRODETECTOR, SUITABLY SUITABLE FOR DETECTING MOTION AND DIRECTIONAL |
| ATE109274T1 (en) * | 1986-06-20 | 1994-08-15 | Lehmann Martin | METHOD AND ARRANGEMENT FOR MEASURING A TEMPERATURE OF A BODY WITHOUT CONTACT. |
| GB8913450D0 (en) * | 1989-06-12 | 1989-08-02 | Philips Electronic Associated | Electrical device manufacture,particularly infrared detector arrays |
| JP2523948B2 (en) * | 1990-06-11 | 1996-08-14 | 松下電器産業株式会社 | Pyroelectric infrared detector |
-
1991
- 1991-06-24 JP JP3151415A patent/JPH04372828A/en active Pending
-
1992
- 1992-04-27 DE DE4292011T patent/DE4292011T1/de active Pending
- 1992-04-27 DE DE4292011A patent/DE4292011C2/en not_active Expired - Fee Related
- 1992-04-27 CA CA002090115A patent/CA2090115C/en not_active Expired - Fee Related
- 1992-04-27 WO PCT/JP1992/000549 patent/WO1993000576A1/en active Application Filing
-
1993
- 1993-02-19 KR KR93700477A patent/KR970003680B1/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| DE4292011T1 (en) | 1993-07-15 |
| WO1993000576A1 (en) | 1993-01-07 |
| KR970003680B1 (en) | 1997-03-21 |
| CA2090115A1 (en) | 1992-12-25 |
| JPH04372828A (en) | 1992-12-25 |
| DE4292011C2 (en) | 1997-09-04 |
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| EEER | Examination request | ||
| MKLA | Lapsed |