Source: http://www.google.com/patents/US5528038?dq=5,675,808
Timestamp: 2014-07-12 11:55:47
Document Index: 657281504

Matched Legal Cases: ['art 4', 'art 4', 'art 4', 'art 40', 'art 40', 'art 40', 'art 40', 'art 40', 'art 4', 'art 83', 'art 83', 'arts 83']

Patent US5528038 - Temperature distribution measurement apparatus and its application to a ... - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign in<nobr>Advanced Patent Search</nobr>PatentsA temperature distribution measurement apparatus has an infrared array sensor that includes a pyroelectric substrate with infrared array receiving electrodes and electrodes for compensation formed on its front side and opposing electrodes formed on its backside. Also included is an infrared lens to focus...http://www.google.com/patents/US5528038?utm_source=gb-gplus-sharePatent US5528038 - Temperature distribution measurement apparatus and its application to a human body detecting systemAdvanced Patent SearchPublication numberUS5528038 APublication typeGrantApplication numberUS 08/232,857Publication dateJun 18, 1996Filing dateApr 22, 1994Priority dateMay 7, 1991Fee statusLapsedPublication number08232857, 232857, US 5528038 A, US 5528038A, US-A-5528038, US5528038 A, US5528038AInventorsNobuyuki Yoshiike, Koji Arita, Susumu KobayashiOriginal AssigneeMatsushita Electric Industrial Co., Ltd.Export CitationBiBTeX, EndNote, RefManPatent Citations (12), Referenced by (9), Classifications (5), Legal Events (5) External Links: USPTO, USPTO Assignment, EspacenetTemperature distribution measurement apparatus and its application to a human body detecting systemUS 5528038 AAbstract A temperature distribution measurement apparatus has an infrared array sensor that includes a pyroelectric substrate with infrared array receiving electrodes and electrodes for compensation formed on its front side and opposing electrodes formed on its backside. Also included is an infrared lens to focus incident infrared lights on the array sensor, a chopper to cut off the incident infrared rays intermittently and a rotating part carrying and rotating parts of the apparatus. The detector elements of the infrared array sensor are laid out vertically and parallel with one another. A horizontal temperature distribution is measured by a lateral scanning with the rotating part rotating horizontally while a vertical temperature distribution is measured by driving the chopper in front of the infrared sensor. Thus, a two dimensional temperature distribution of an empty space is measured. The number and the position of persons in the empty space attained from the temperature distribution measurement data is useful for controlling air conditioners.
What is claimed is: 1. A temperature distribution measurement apparatus comprising:a) an infrared array sensor that includes a plurality of detector elements, b) focusing means that includes an infrared lens for focusing incident infrared rays on the infrared array sensor, c) chopping means for intermittently shielding the incident infrared rays from said plurality of detector elements, and d) rotating means for supporting and rotating together about an axis of rotation said infrared array sensor, said focusing means, and said chopping means, said axis of rotation intersects said plurality of detector elements. 2. A temperature distribution measurement apparatus comprising:a) an infrared array sensor that includes a plurality of detector elements, b) focusing means that includes an infrared lens for focusing incident infrared rays on the infrared array sensor, c) chopping means for intermittently shielding incident infrared rays from said plurality of detector elements, and d) rotating means for supporting and rotating together about an axis of rotation said infrared array sensor, said focusing means, and said chopping means, said rotating means rotates in synchronization with said chopping means, and said focusing means and said chopping means are positioned so that said incident infrared rays travel along a straight line between an object emitting said incident infrared rays and said focusing means. 3. The temperature distribution measurement apparatus of claim 2, wherein said plurality of infrared detector elements are formed adjacent to each other and adjacent to and parallel to said axis of rotation.
4. The temperature distribution measurement apparatus of claim 3, wherein said plurality of infrared detector elements are vertically stacked; and wherein said temperature distribution measurement apparatus further comprises:a) horizontal temperature measurement means for generating horizontal temperature distribution measurements by laterally rotating said rotating body rotating means; b) vertical temperature measurement means for generating vertical temperature distribution measurements by driving said chopping means; and c) two-dimensional temperature measurement means for generating spatial temperature distribution measurements by electrically combining said vertical and said horizontal temperature distribution measurements. 5. The temperature distribution measurement apparatus of claim 2, further comprising a stop switch for generating a switching signal to initiate a reverse rotation following a completion of forward rotation and wherein:a) said rotating means incrementally rotates said infrared array sensor; b) said chopping means shields a plurality of incident infrared rays from said plurality of detector elements at least one time for each angular increment; and c) said temperature distribution measurement apparatus further comprises a peak-holding circuit for obtaining a peak measurement output of each detector element while said detector elements are shielded from the plurality of incident infrared rays by said chopping means. 6. The temperature distribution measurement apparatus of claim 2, further comprising:a) computational means for determining number and position of persons in a space by measuring a temperature distribution in said space; and b) detector means for detecting movements of persons by analyzing changes in said temperature distribution of said space with respect to time. 7. The temperature distribution measurement apparatus of claim 6 further comprising an estimator means for estimating number and position of persons in said space using a membership function based on fuzzy theory.
8. An infrared array sensor comprising:a pyroelectric infrared array sensor comprising: (a) a pyroelectric substrate, (b) a multiple number of electrode pairs formed on the front side of said substrate at a certain distance in an array with a pair of said multiple number of electrode pairs including a first electrode for receiving infrared rays and a second electrode for compensation, said first electrode and said second electrode being connected electrically with each other through an electrode connecting part, (c) a multiple number of opposing electrode pairs formed on the back side of said substrate at the positions corresponding to those of said electrode pairs of the front side of the substrate, each opposing electrode of said multiple number of opposing electrode pairs corresponding to said electrodes for compensation are coupled to each other to form a single common electrode, lead out electrodes formed on the back side of said substrate which connect the multiple number of opposing electrodes to external electrical circuits, and a masking plate to shield the incident infrared rays off the electrodes for compensation while letting the infrared rays hit the receiving electrodes. 9. The infrared array sensor of claim 8, wherein said pyroelectric array sensor further includestwo rows of said multiple number of electrode pairs formed in an array pattern, and said opposing electrode pairs formed on the back side of said substrate on positions other than those corresponding to said electrode connecting parts formed on the front side of said substrate. 10. The infrared array sensor of claim 8, wherein said plurality of opposing electrode pairs formed on the back side of said substrate comprise:a) a plurality of opposing electrodes at positions corresponding to those of said electrodes for receiving infrared rays, and b) a broad electrode formed as the common opposing electrode to positions corresponding to those of said electrodes for compensation. Description
FIELD OF THE INVENTION This invention relates to a temperature radiation distribution measurement apparatus that utilizes a pyroelectric type infrared sensor and its application to a human body detecting system.
BACKGROUND OF THE INVENTION In recent years there has been a mounting demand for measurement of the room temperature distribution to detect the presence of human beings and their motion in a room in connection with security maintenance and air conditioning.
SUMMARY OF THE INVENTION This invention comprises an array sensor to detect infrared radiations, a focusing means composed of infrared lenses to focus infrared radiations on the array sensor, a chopping means that intermittently shields the incident infrared rays (together with a rotating part) and a driving means that rotates the rotating part in the direction of the shorter axis of the array sensor. The above set-up may be applied to a human body detecting system.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially cutaway perspective view to show the outline of a temperature distribution measurement apparatus as an embodiment of this invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS Example 1 FIG. 1 illustrates an exemplary embodiment of this invention. A rotating part 4 has a pyroelectric type infrared sensor array 1 wherein eight receiving elements are laid out vertically one after another. A silicone infrared lens 2 is positioned in front of the array sensor 1 to focus incident infrared rays on the pyroelectric sensor array. A chopper 3 in front of the lens 2 cuts off the incident infrared rays intermittently. The rotating part 4 is linked mechanically with a stepping motor 5.
Now, the array sensor 1 is installed with its longer axis positioned vertically and the chopper is driven at 10 Hz. Then, the vertical dose distribution of the thermal radiations, namely, the vertical temperature distribution of the space facing the array sensor 1 and the lens 2 can be measured every 1/10 second. The ranges of the space that can be covered by the measurement are dependent on the viewing angle of the lens 2 and the sensor dimensions and the vertical space resolution is decided by the number of the infrared receiving electrodes as installed in the array sensor 1. For example, when the viewing angle of the lens 2 is 80 degrees and the array sensor 1 has 10 receiving electrodes, the vertical resolving power is 10 and each electrode takes care of 8 degrees in temperature measurement. Next, the stepping motor 5 is turned on and the rotating part 4 is rotated intermittently. Thus, by changing the direction of the array sensor 1 and the lens 2 right and left, and also by driving the chopper 3 in the same way as in the foregoing, a temperature distribution is measured. After this measurement, the temperature distribution in the respective directions is connected with each other and a reversed two-dimensional temperature distribution in the open space is obtained. The horizontal (right and left) resolution is dependent on the rotational angle per one step of the stepping motor 5. For example, when signals are inputted every 3.6 degree rotation and a rotation of 180 degrees in total is completed, the horizontal space resolution becomes 50. This makes it possible to measure the temperature distribution of an open space from the sensor position in a scope of 80 degrees vertically and 180 degrees horizontally with a resolving power of 10�50.
Example 2 FIG. 3 shows a block diagram relating to the electrical signals of the measurement apparatus. An I/O port 18 is electrically connected with a stepping motor driver 15, a chopper driver 13, a sensor signal processor 11 and CPU 14. The CPU 14 is further connected with a clock signal generator 16 and a data memory 17. FIG. 4 shows the timing of various electrical signals.
Thus, the temperature distribution of the open space can be measured with a resolving power of n�m.
Example 3 With the help of FIGS. 5(a), 5(b) and 5(c), another specific example of an embodiment of this invention is explained. A rotating part 40 has a pyroelectric type infrared array sensor 10 wherein a multiple number of receiving elements are laid out in a linear form and a silicone infrared lens 20 in front of the array sensor 10. Thus, the incident infrared rays are focused on the pyroelectric sensor array. Furthermore, a chopper 30 in front of the lens cuts off the incident infrared rays intermittently. By a partial rotation of the chopper 30 with a guide pin 31 serving as a fixed point, a chopping of the infrared rays entering into the lens 20 is made possible. A permanent magnet 32 is fixed on the chopper 30 and a miniature solenoid 33 drives the chopper into a motion as the electromagnetic field changes according to the electric current flowing into the solenoid. The rotating part 40 is linked mechanically through a connecting means with the Stepping motor 50.
Example 4 In the next, FIGS. 6(a), 6(b) and 6(c) show another mechanical construction. A rotating part 40 has a pyroelectric type infrared array sensor 10 wherein a multiple number of receiving elements are laid out and a silicone infrared lens in front of the array sensor 10. Thus, the incident infrared rays are focused on the pyroelectric array sensor 10. Further, a disc type chopper 35 in front of the lens 20 cuts off the incident infrared rays intermittently. The chopper 35 is rotated with a shaft 36 serving as a fixed point. By a hole made on a part of the disc type chopper 35, a chopping action is applied to the infrared rays entering into the lens 20. Item 37 is a miniature motor and the chopper 35 is rotated by this motor. The rotating part 40 is linked with a stepping motor 50 mechanically through a connecting means 51. Item 70 is a mainframe of the sensor drive mechanism and holds the rotating part 40 firmly.
Example 5 Now, an explanation is given to an exemplary embodiment wherein a temperature distribution measurement apparatus of this invention is applied to a human body detecting system.
A measurement apparatus of the foregoing example is installed to the upper part of the walls of a room that measure about 6 meters by 6 meters to measure the temperature distribution of the whole room. The number of the receiving elements is chosen as 10 and the right and left rotational steps are set at 40. Then, the temperature distribution of the open space is expressed by a matrix of 10�40 as follows: ##EQU2##
Example 6 In another exemplary embodiment of this invention, a stepping motor 5 is rotated in the reverse direction after finishing the measurement of the last plane direction and the apparatus is returned to the initial plane direction in the waiting state for the next round of measurement.
At this moment, the chopper driver 13 is also inputted with a chopper drive signal (d), ON or OFF signal, and the chopper 3 is either opened or closed. Here, as shown in the drawing, by having the stepping signal and the chopper signal synchronized, proper timing is made possible. The output from each sensor is illustrated in FIG. 7(e) in tune with the OPEN/CLOSE of the chopper 3. The output is then stored in the data memory 17 through the sensor signal processor 11. When the number of the sensor receiving elements is n, the data addresses are expressed, for example, as S01, S02, - - - , S0n. After the storage of the data, the next stepping motor drive signals are outputted by the CPU 14. At the same time, chopper drive signals of ON/OFF are outputted and measurement for the next direction is started. After the measurement, the data addresses are set forth as S11, S12, - - - , S1n. In this way measurements are repeated with the directions changed m times. When the measurement for the last direction (m'th measurement) is finished, the stepping motor drive signal is changed to the backward direction (LOW for example) by a signal from the CPU 14. The stepping motor 5 is then rotated in reverse at great speed by a total angle of m�θ degrees. (c) Now, the sensor plane is returned to the initial direction and the whole set-up of the measurement is kept at a waiting status. (Step S 4) The reverse rotation speed is made as high as possible. Next, the measurement data is fed into the CPU 14 (Step S 5) and processed in a matrix relation as set forth below to obtain the space temperature distribution with a resolving power of n�m. ##EQU3##
Now, a temperature distribution is measured at this time by scanning the space area facing the array sensor 1 and the lens 2 with the rotating part 4 rotating intermittently in the forward direction and the chopper 3 being driven in the same way as described in the foregoing. At the completion of the measurement, a series of the data on the vertical temperature distribution for one direction are put together by a signal processing to get a two-dimensional temperature distribution of the open space in a reversed form. The horizontal (right and left) space resolving power is dependent on the rotation angle per step of the stepping motor 5. For example, when signals are inputted, every rotational movement is 3.6 degrees and the total angle of rotation is 180 degrees, the horizontal space resolving power equals to 50 and an open space extending horizontally over 180 degrees and vertically over 80 degrees from the sensor position is covered with a resolving power of 10�50 at an interval of a few minutes in the measurement of the temperature distribution.
Example 7 Another exemplary embodiment of this invention is described wherein the stepping motor 5 is driven by a different driving method.
Example 8 FIG. 10, FIG. 11 and FIG. 12 are schematic illustrations of pyroelectric bodies to explain exemplary embodiments of this invention. As shown in FIG. 10, a pyroelectric substrate 80 comprising PbTiO3, etc. that are made into a thin plate form by cutting and polishing processes, has a multiple number of receiving electrode 81 and compensating electrode 82 over its front surface formed by an evaporation process or by a sputtering process. Each of the foregoing electrodes has a provision for electrical connection through a connecting part 83. Furthermore, on the back side of the pyroelectric substrate 80, there are opposing electrodes for receiving 83 and opposing electrodes 84 both formed by an evaporation process or by a sputtering process and at the positions opposite to those of the receiving electrodes 81 and the compensating electrodes 82 respectively. Also lead out electrodes 85 are formed by the same process as employed in forming other electrodes and are intended for acting as a connecting means to connect electrically to external electrical circuits. The electrode patterns can be formed either by a metal masking method or by a photolithograph method. In this processing, it is better to have the distance between adjacent electrodes of the receiving electrodes ranged from 10 to 200 μm and the distance between the receiving electrode 81 and the compensating electrode 82, e.g., the length of the electrode connecting part 83, ranged from 500 μm to 2 μm. Also, it is desirable to make the areas of the receiving electrode and the compensating electrode equal to each other. The width of the electrode connecting part and the lead out electrode is better with the one ranging from 20 to 100 μm.
Actually, receiving electrodes and compensating electrodes are formed on a single pyroelectric substrate in a 10 element array and an infrared ray lens system having a viewing angle of 80 degrees are put together to build a measurement apparatus. Resultant accuracy of measurement shows �0.2� C. and a space resolving power of 10 (8 degrees) in detecting a one-dimensional temperature distribution of an open space along the direction of the array.
Since the vertical space resolving power is 10 as mentioned in the foregoing, an open space with the extent of 80 degrees vertically and 180 degrees horizontally (from the sensor position) is covered in the temperature distribution measurement with an accuracy of �0.2� C. and a space resolving power of 10�50.
Example 9 In connection with the configuration of the pyroelectric electrodes as described in Example 8, the opposing electrodes for compensation to be formed on the back side of the pyroelectric substrate are made into a single broad electrode called a common opposing electrode for compensation 104 as shown in FIG. 14.
Example 10 Another example of electrode patterns to be formed on the pyroelectric substrate is illustrated in FIGS. 15(a) and 15(b). As shown in FIGS. 15(a) and 15(b), receiving electrodes 81, electrode connecting parts 83 and compensating electrodes 82 are formed in two identical groups on the front side of a pyroelectric substrate 105. On the back side of a pyroelectric substrate 106, opposing electrodes for receiving 86 and opposing electrodes for compensation 84 are formed at the places corresponding to those of the receiving electrodes and compensating electrodes respectively. Item 85 is a lead out electrode to connect the various electrodes to the external circuits. The dimensions of all the electrodes are the same as in Example 8.
Actually, an arrangement of two lines of receiving electrodes and compensating electrodes formed on a single pyroelectric substrate in a 10 element array respectively with a masking plate installed above the pyroelectric substrate to pass the incident infrared rays only to the receiving electrodes, coupled with the use of an infrared ray lens system of 80 degree viewing angle has made it possible to measure the two-dimensional temperature distribution of an open space with an accuracy of �0.2� C. and a space resolving power of 2�10.
Next, in the same way as in Example 8 the pyroelectric substrate, the selective infrared penetrating substrate, the infrared penetrating lens and the chopper are put together to compose an integral body of the rotating part which is then linked mechanically to the stepping motor. Then, while chopping is applied to the receiving electrodes vertically along the direction of the array (in the direction of the longer axis), the stepping motor is driven to rotate the rotating part intermittently in the horizontal direction. Thus, the temperature distribution of an open space is measured by having the area facing the sensor and the lens scanned right and left. By connecting the vertical temperature distribution of each horizontal direction through the means of an electrical signal processing after the data acquisition, a two dimensional reversed temperature distribution of the open space is obtained. The horizontal (right and left) space resolving power is dependent on the rotating angle per step of the stepping motor. When a signal is inputted every 3.6 degrees of rotation and a total of 180 degrees is covered for example, the horizontal space resolving power gained is 100. Since the vertical space resolving power is 10 as mentioned in the foregoing, an open space with an extent of 80 degrees vertically and 180 degrees horizontally from the sensor position is covered in the temperature distribution measurement with an accuracy of �0.2� C. and a space resolving power of 10�100.
Example 11 It is desirable to have the same patterns for both of the receiving electrodes and the compensating electrodes. However, depending on the case as shown in FIGS. 17(a) and 17(b), the patterns can be different from each other as long as the areas of the receiving electrodes and the compensating electrodes are kept the same with each other. By that way, it is easier to design the patterns of the lead out electrodes on the back side of the pyroelectric substrate 106 in particular by having the lead out electrodes extended out from both ends of the pyroelectric substrate. Also, in order to reduce the number of the lead out electrodes, the opposing electrodes for compensation to be formed on the back side of the pyroelectric substrate are combined into a single broad electrode of common opposing electrode for compensation 104 as illustrated in FIGS. 18(a) and 18(b). In this case, the common opposing electrode for compensation is designed to match in location with all the compensating electrodes 82 formed on the front side of the pyroelectric substrate. Thus, the number of the lead out electrode for the compensating electrode 85 is reduced to only two and the electrical connection between the pyroelectric substrate and the external electric circuits is simplified.
Example 12 The performance of the temperature distribution measurement apparatus of this invention can be enhanced by using it together with various electric circuits.
Example 13 A block diagram of the measurement circuit incorporating a peak hold function as used with the temperature distribution measurement apparatus of this invention is shown in FIG. 23. The output signals from a sensor 110 having a multiple number of elements are amplified by an amplifier 112 after the signals are fed into a filter circuit III for noise elimination. The amplified signal corresponding to each of the sensor elements is then inputted in succession to an A/D converter 115 through a multiplexer 114 whereby each sensor signal is fed to the A/D converter at a certain fixed sampling frequency. The resultant A/D converted digital signals are then inputted into a CPU 116 having a memory for storing data, a processor and a clock signal generator. The multiplexer 114 and a chopper 119 are driven by the CPU 116. Item 117 is an I/O board whereby the chopper 117 is controlled.
Example 14 Now, another exemplary embodiment of this invention is explained in the following:
Example 15 A block diagram of measurement circuit is shown in FIG. 29. The output signals from a sensor 110 having a multiple number of sensor elements are amplified at an amplifier 112 after a filter 111 for noise elimination. The amplified signal corresponding to the output of each sensor element is then sampled in sequence at a certain sampling frequency by a multiplexer 114 and outputted to an A/D converter 115 for A/D conversion. Item 116 is a CPU which has a memory for storing data, a processor and a clock signal generator. Item 117 is an I/O board for controlling a chopper 119 and a stepping motor 118. A timing chart for the stepping motor drive signal, the chopper drive signal and the sensor output signal is shown in FIGS. 30(a), 30(b), and 30(c).
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS4072863 *Oct 26, 1976Feb 7, 1978Roundy Carlos BPyroelectric infrared detection systemUS4556796 *Jun 11, 1984Dec 3, 1985U.S. Philips CorporationInfrared radiation detectorUS4973843 *Aug 29, 1989Nov 27, 1990Murata Mfg. Co., Ltd.Pyroelectric infrared sensorUS5008522 *May 27, 1988Apr 16, 1991Saab Missiles AktiebolagDevice for the selective detection of objectsUS5045699 *Aug 3, 1989Sep 3, 1991Deutsche Airbus GmbhHeat imaging camera with a cooled detector mosaicGB2105460A * Title not availableJPH01185420A * Title not availableJPS6056229A * Title not availableJPS57124981A * Title not availableJPS57175931A * Title not availableJPS61186826A * Title not availableJPS61290330A * Title not available* Cited by examinerReferenced byCiting PatentFiling datePublication dateApplicantTitleUS5789751 *Nov 13, 1995Aug 4, 1998Samsung Electro-Mechanics Co., Ltd.Non-directional pyroelectric infrared sensorUS5826980 *Aug 28, 1996Oct 27, 1998Matsushita Electric Industrial Co., Ltd.Non-contact thermometerUS6252506 *Sep 22, 1999Jun 26, 2001Yuan-Tai HsiehDevice for finding a position of a humanUS7326932 *Jan 26, 2005Feb 5, 2008Analog Devices, Inc.Sensor and cap arrangementUS7718967Oct 20, 2006May 18, 2010Analog Devices, Inc.Die temperature sensorsUS7807972Feb 11, 2008Oct 5, 2010Analog Devices, Inc.Radiation sensor with cap and optical elementsUS8487260Oct 20, 2006Jul 16, 2013Analog Devices, Inc.SensorUS8523427Feb 27, 2008Sep 3, 2013Analog Devices, Inc.Sensor device with improved sensitivity to temperature variation in a semiconductor substrateUS20130119253 *Nov 15, 2012May 16, 2013Visonic Ltd.Motion detection systems and methodologies* Cited by examinerClassifications U.S. Classification250/342, 250/338.3International ClassificationG01J5/34Cooperative ClassificationG01J5/34European ClassificationG01J5/34Legal EventsDateCodeEventDescriptionAug 5, 2008FPExpired due to failure to pay maintenance feeEffective date: 20080618Jun 18, 2008LAPSLapse for failure to pay maintenance feesDec 24, 2007REMIMaintenance fee reminder mailedNov 18, 2003FPAYFee paymentYear of fee payment: 8Dec 6, 1999FPAYFee paymentYear of fee payment: 4RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services©2012 Google