US20120073308A1

US20120073308A1 - Apparatus and method for controlling the temperature of a black body

Info

Publication number: US20120073308A1
Application number: US13/375,750
Authority: US
Inventors: Geon Hee Kim; Jeong Min Lee; Sun Choel Yang; Ki Soo Chang; Hyo Sik Kim; Moon Seop Yang
Original assignee: Korea Basic Science Institute KBSI
Current assignee: Korea Basic Science Institute KBSI
Priority date: 2009-11-06
Filing date: 2010-11-05
Publication date: 2012-03-29
Also published as: WO2011056010A3; KR20110049996A; WO2011056010A2; KR101081378B1

Abstract

Provided is an apparatus for controlling temperature of a black body. The apparatus includes a black body emitting radiant energy of infrared rays; a first Peltier element adjacent to the black body, the first Peltier element having a 1a surface and a 1b surface that selectively emit or absorb heat; a copper plate adjacent to the 1b surface; a second Peltier element adjacent to the 2b surface, the second Peltier element having a 2a surface and a 2b surface that selectively emit or absorb heat; a heat transfer member comprising a bent surface adjacent to the 2a surface, and an arm extending toward both ends of the black body to be adjacent to the both ends of the black body and a control unit controlling the 2a surface to emit heat when the 1a surface emits heat, and the 2a surface to absorb heat when the 1a surface absorbs heat.

Description

BACKGROUND OF THE INVENTION

The present invention relates to an apparatus and method for controlling the temperature of a black body, and more particularly, to an apparatus and method for controlling the temperature of a black body using a Peltier element.
Generally, a black body is used for test and temperature correction of a thermal imaging camera. Since the emissivity of a black body is about 1, it emits almost 100% of its energy. The thermal imaging camera includes a detector for sensing a black body. The detector is formed of a sensor array with a plurality of detecting sensors. For an example, one detector is formed of a sensor array including 76,800 sensors, i.e., 320 sensors horizontally and 240 sensors vertically. Such an array is called Focal Plane Array (FPA).
However, each of sensors that constitute a sensor array shows a little difference in its performance due to errors during a manufacturing process. Particularly, this phenomenon, unevenness of performance level, is especially critical for detectors in thermal imaging cameras. Thus, when an electronic circuit is assembled and images are generated, it is hard to recognize the images because the sensors have such a great difference in their performance capability. A device is needed to compensate for different performances of sensors in the thermal imaging camera using ambient temperature and the temperature of black body source such that such characteristics show almost uniform performance through compensation and correction in advance.
In domestic military and specialized industry fields, military thermal imaging apparatuses and medical thermo-graphic imaging apparatuses are generally imported, which are technologies that are not common in private sectors of industry. In the field of software adequate for user environments, standard measuring and analyzing devices for thermal image apparatuses have not been developed at all.
In the global market, there are SBIR from the U.S., CI from Israel, MICRON from EU produce black bodies as manufacturers of black bodies, and there are Chinese manufacturers that produce low-price products. SBIR is the company that has the most advanced technology among them, developing and selling various black bodies. However, even SBIR is not adopting a black body with vacuum package for fine temperature stabilization.
Since the technology for temperature correction is not actively developed neither domestically nor internationally, errors cannot be corrected, causing miscalculation to the measured values. Accordingly, a technology for temperature correction and performance evaluation of a thermal imaging camera that changes a difference in infrared radiant energy into an image visible to human eyes needs to be developed.

SUMMARY OF THE INVENTION

The present invention provides an apparatus and method for controlling the temperature of a black body in which temperature distribution is uniform.
The present invention also provides an apparatus and method for controlling the temperature of a black body by changing the temperature of the black body into a desired temperature and photographing the black body using a thermal imaging camera.
In accordance with an exemplary embodiment, an apparatus for controlling temperature of a black body includes: a black body emitting radiant energy of infrared rays; a first Peltier element adjacent to the black body, the first Peltier element having a 1a surface and a 1b surface that selectively emit or absorb heat; a copper plate adjacent to the 1b surface; a second Peltier element adjacent to a 2b surface, The second Peltier element having a 2a surface and the 2b surface that selectively emit or absorb heat; a heat transfer member comprising a bent surface adjacent to the 2a surface, and an arm extending toward both ends of the black body to be adjacent to the both ends of the black body; and a control unit controlling the 2a surface to emit heat simultaneously when the 1a surface emits heat, and the 2a surface to absorb heat simultaneously when the 1a surface absorbs heat.
Particularly, when the black body is cooled, the temperature of the 1a surface may be lower than the temperature of the 2a surface.
And, when the black body is heated, the temperature of the 1a surface may be higher than the temperature of the 2a surface.
Further, the second Peltier element has a through hole at the center thereof, and the apparatus further comprises a heat-emitting member contacting the copper plate to exhaust heat generated in the copper plate.
The heat-emitting member may include a heat-emitting plate connected to the copper plate, which performs heat exchange in a water-cooling manner or in an air-cooling manner.
In accordance with another exemplary embodiment, a method for controlling temperature of a black body includes: measuring temperature of the black body emitting radiant energy of infrared rays; determining whether the measured temperature is higher or lower than a predetermined temperature; and emitting heat from a 1a surface adjacent to the black body and a 2a surface of a second Peltier element adjacent to a heat transfer member comprising an arm adjacent to both ends of the black body 2 when the measured temperature is lower than the predetermined temperature, and absorbing heat into the 1a surface and the 2a surface adjacent to the black body when the measured temperature is higher than the predetermined temperature.
When heat is emitted from the 1a surface, the temperature of the 1a surface may be lower than the temperature of the 2a surface, and when heat is absorbed into the 1a surface, the temperature of the 1a surface may be higher than the temperature of the 2a surface.
In accordance with embodiments, an apparatus and method for controlling the temperature of a black body can be applied to apparatuses for evaluating performance and reliability of a thermal imaging camera for monitoring a forward area, testers for performance of a semiconductor wiper block, non-destructive thermo-conductive analysis in the non-destructive field, medical equipment for diagnosing body heat, and, and satellite mounted optical systems for infrared rays, thereby securing calibration technology.
Also, a dual Peltier element structure is used for heating and cooling of a black body, increasing the cooling efficiency. A temperature compensation plate near both ends of a black body is connected to the dual Peltier element structure to allow the black body to have uniform temperature distribution and thus reduce a deviation between temperatures of the center and the edge of the black body, thereby efficiently heating and cooling the dual Peltier element structure together with the black body and miniaturizing them.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments can be understood in more detail from the following description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a view illustrating an arrangement of Peltier elements according to an embodiment of the present invention;

FIG. 2 is a view illustrating an apparatus for controlling the temperature of a black body in an air-cooling manner according to an embodiment of the present invention;

FIG. 3 is a view illustrating an apparatus for controlling the temperature of a black body in a water-cooling manner according to an embodiment of the present invention; and

FIG. 4 is a flowchart illustrating a method for controlling the temperature of a black body according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a view illustrating an arrangement of Peltier elements according to an embodiment of the present invention. However, detailed configuration including a through hole is not shown in FIG. 1.
Generally, Peltier elements include thermoelectric elements that are disposed in parallel to each other and include a semiconductor with N-type impurity ions and a semiconductor with P-type impurity ions. Electrodes formed of copper plate may be coupled to an upper side and a lower side of the thermoelectric element. Also, a ceramic substrate may be attached to surround the electrodes.
The Peltier elements generate a Peltier effect in which an upper portion is cooled and a lower portion is heated because heat is emitted from the upper portion to the lower portion while electrons of an N-type semiconductor or holes of a P-type semiconductor move from an upper electrode to a lower electrode by application of a current to a junction. The Peltier effect, which is one of electrical phenomena, refers to a phenomenon in which when a current is applied to a junction between two different types of metal, heat is generated or absorbed at the junction.
Accordingly, when a current is applied to a Peltier element, one side of the Peltier forms a heat-absorbing surface of a low temperature, and the other side thereof forms a heat-emitting surface of a high temperature. If a current is applied in the reverse direction, the heat-absorbing surface and the heat-emitting surface may be switched.
As shown in FIG. 1, a first Peltier element 10 and a second Peltier element 20 may be arranged, and a copper plate 30 may be disposed between the first Peltier element 10 and the second Peltier element 20.
The first Peltier element 10 may have a 1a surface 12 and a 1b surface 14 that can selectively emit or absorb heat, and the second Peltier element 20 may have a 2a surface 22 and a 2b surface 24 that can selectively emit or absorb heat.
Particularly, the 1a surface 12, the 1b surface 14, the 2b surface 24, and the 2a surface 22 may be arranged sequentially from right to left. When an exothermic reaction occurs in the 1a surface 12, an exothermic reaction may also occur in the 2a surface 22. On the other hand, when an endothermic reaction occurs in the 1a surface 12, an endothermic reaction may also occur in the 2a surface 22.
FIG. 2 is a view illustrating an apparatus for controlling the temperature of a black body in an air-cooling manner according to an embodiment of the present invention.
An apparatus for controlling the temperature of a black body according to an embodiment of the present invention may include a black body 2 emitting radiant energy of infrared rays, a first Peltier element 10 adjacent to the black body 2, a copper plate 30 adjacent to the 1b surface 14, a second Peltier element 20 adjacent to the copper plate 30, and a heat transfer member 40 adjacent to the 2a surface 22.
The apparatus for controlling the temperature of the black body may further include a control unit 50. The control unit may control the 2a surface 22 to emit heat simultaneously when the 1a surface 12 emits heat, and control the 2a surface 22 to absorb simultaneously when the 1a surface 12 absorbs heat. In other words, the control unit 50 may control the 2b surface 24 to emit heat simultaneously when the 1b surface 14 emits heat and control the 2b surface 24 to absorb heat simultaneously when the 1b surface 14 absorbs heat.
The heat transfer member 40 may include a bent surface adjacent to the 2a surface 22, and an arm 44 connected to the bent surface 42. The arm 44 may extend toward to both ends of the black body 2 to deliver heat received from the surface 2 a and the bent surface 42 to the black body 2.
A through hole 26 may be formed in the center of the second Peltier element 20. A heat-emitting member 27 may be disposed in the through hole 26. The heat-emitting member 27 may contact the copper plate 30 to emit heat generated from the copper plate 30. When the temperature of the copper plate 30 is higher than the outside temperature, the heat-emitting member 27 may be heated to exhaust heat of the copper plate 30 to the outside. When the temperature of the copper plate 30 is lower than the outside temperature, the heat-emitting member 27 may be cooled to supply heat to the copper plate 30.
As shown in FIG. 2, a heat-emitting plate 28 may be disposed at one end of the heat-emitting member 27 to exchange heat with the outside. The heat-emitting plate 28 may include a plurality of cooling fins. A fan 60 may be provided in the heat-emitting plate 28 to efficiently perform heat exchange in an air-cooling manner.
Since the heat exchange by the heat-emitting plate 28 and the fan 60 is performed similarly to the principle of a heat exchanger, a detailed description thereof will be omitted herein.
The control unit 50 may control the operation of the fan 60 to improve the efficiency of heat exchange performed by the heat-emitting plate 28. For example, when the temperature of the heat-emitting plate 28 is higher or lower than normal temperature, the fan 60 may be operated to facilitate the heat exchange.
The control unit 50 may heat or cool the black body 2 by controlling the direction of a current flowing in the first Peltier element 10 and the second Peltier element 20, and may exchange heat delivered to the copper plate 30 with the outside by controlling the fan 60.
FIG. 3 is a view illustrating an apparatus for controlling the temperature of a black body in a water-cooling manner according to an embodiment of the present invention. The apparatus shown in FIG. 3 differs from that of FIG. 2 in that heat exchange is performed using water, and other features thereof are similar to those of FIG. 2. Therefore, the following description of the apparatus of FIG. 3 will be focused on the difference from that of FIG. 2.
A receiving unit 62 may be disposed adjacent to the heat-emitting plate 28. The receiving unit 62 may receive water and allow water to circulate for heat exchange. Since the heat exchange by the heat-emitting plate 28 and the receiving unit 62 is performed similarly to the principle of a heat exchanger, a detailed description thereof will be omitted herein.
Unlike that of FIG. 2, the control unit 50 may control the flow rate and the flow amount of cooling water in the receiving unit 62. When the temperature of the heat-emitting plate 28 is higher or lower than normal temperature, or when heat exchange needs to be promptly performed, the control unit 50 may control the flow rate of water such that heat exchange can be smoothly performed between the receiving unit 62 and the heat-emitting plate 28.
FIG. 4 is a flowchart illustrating a method for controlling the temperature of a black body according to an embodiment of the present invention. Hereinafter, a detailed description of the method will be made with reference to FIG. 4.
It is difficult for sensors installed in a thermal imaging camera to measure exact values due to the characteristics of sensors or external factors. Accordingly, correction or compensation may be performed on the sensors by measuring energy emitted from the black body while varying the temperature of the black body.
Temperature to be measured by a thermal imaging camera is set. In this case, if there are a variety of temperatures to be measured by the thermal imaging camera, the predetermined temperature may be diversified. Generally, when correcting the thermal imaging camera, the predetermined temperature may be selected in plurality from a temperature range of about −10° C. to about 70° C.
The temperature of the black body 2 may be measure (S10).
The measured temperature of the black body 2 may be compared with the predetermined temperature (S20).
If the measured temperature is higher than the predetermined temperature (S30), the temperature of the black body 2 may need to be cooled to the predetermined temperature (S42). Accordingly, the control unit 50 may apply a current to the first Peltier element 10 and the second Peltier element 20 such that the 1a surface 12 of the first Peltier element 10 and the 2a surface 22 of the second Peltier element 20 serve as a heat-absorbing surface. In this case, since the 1b surface 14 of the first Peltier element 10 and the 2b surface 24 of the second Peltier element 20 serve as a heat-emitting surface, the temperature thereof may rise.
Since the temperature T1 of the 1a surface 12 decreases, the black body 2 adjacent to the 1a surface 12 may be cooled. In this case, the temperature at the central portion of the black body 2 may become lower than the temperature at both ends of the black body 2. In other words, the temperature distribution of the black body 2 may form a two-dimensional curve in which the temperature is the more low at the center thereof. More convection of external air may occur at both ends of the black body 2 and both ends of the 1a surface 12 than at their central portions, and the cooling effect is not uniform on the whole of the 1a surface 12 in practice, not in theory.
The temperature T2 of the 2a surface 22 may be set lower than the temperature T1 of the 1a surface 12 (S44). The temperature T2 may be delivered to the bent surface 42 adjacent to the 2a surface 22, and the bent surface 42 may be connected to the arm 44 such that heat transfer is possible. Accordingly, temperature T2 may be substantially delivered to the arm 44. Since the arm 44 is adjacent to the both ends of the black body 2, the both ends of the black body 2 may be cooled by the arm 44. Furthermore, since the temperature T2 is lower than the temperature T1, the both ends of the black body 2 may be cooled to a temperature lower than the temperature T1 of the 1a surface 12 by the temperature T2 of the 2a surface 22. Accordingly, the temperature of the black body 2 may be corrected such that the temperature is uniform at the both ends and the central portion of the black body 2. On the other hand, heat may be generated from the 1b surface 14 and the 2b surface 24. The generated heat may be delivered to the copper plate 30, and then may be delivered from the copper plate 30 to the heat-emitting plate 28 connected to the heat-emitting member 27, allowing heat to be exchanged by the fan 60 or the receiving unit 62 in an air-cooling manner or a water-cooling manner.
If heat is not emitted to the outside by the copper plate 30, the black body 2 may not be cooled to a desired temperature due to heat generated in the 1b surface 14 and the 2b surface 24. Although not shown in the drawings, the first Peltier element 10 and the second Peltier element 20 may be airtightly disposed in one case, and heat by the 1b surface 14 and the 2b surface 24 may affect the 1a surface 12 and the 2a surface 22.
When the measured temperature is lower than the predetermined temperature, the black body 2 may need to be heated to the predetermined temperature (S52). Accordingly, the control unit 50 may apply a current to the first Peltier element 10 and the second Peltier element 20 such that the 1a surface 12 of the first Peltier element 10 and the 2a surface 22 of the second Peltier element 20 serve as a heat-emitting surface. In this case, since the 1b surface 14 of the first Peltier element 10 and the 2b surface 24 of the second Peltier element 20 serve as a heat-absorbing surface, the temperature thereof may fall.
Since the temperature T1 of the 1a surface 12 increases, the black body 2 adjacent to the 1a surface 12 may be heated. In this case, the temperature at the central portion of the black body 2 may become higher than the temperature at both ends of the black body 2. In other words, the temperature distribution of the black body 2 may form a two-dimensional curve in which the temperature is highest at the center thereof. More convection of external air may occur at both ends of the black body 2 and both ends of the 1a surface 12 than at their central portions, and the heating effect is not uniform on the whole of the 1a surface 12 in practice, not in theory.
The temperature T2 of the 2a surface 22 may be set higher than the temperature T1 of the 1a surface 12 (S44). The temperature T2 may be delivered to the bent surface 42 adjacent to the 2a surface 22, and the bent surface 42 may be connected to the arm 44. Accordingly, temperature T2 may be substantially delivered to the arm 44. Since the arm 44 is adjacent to the both ends of the black body 2, the both ends of the black body 2 may be heated by the arm 44. Furthermore, since the temperature T2 is higher than the temperature T1, the both ends of the black body 2 may be heated, thereby correcting the temperature of the black body 2 to be uniform at the both ends and the central portion of the black body 2. Accordingly, the thermal distribution may form a straight line, not a quadratic curve.
On the other hand, the 1b surface 14 and the 2b surface 24 may be cooled. The cooled surfaces 14 and 24 may affect the copper plate 30, and then the copper plate 30 may affect the heat-emitting plate 28 connected to the heat-emitting member 27. Thereafter, heat exchange may be performed by the fan 60 or the receiving unit 62 in an air-cooling manner or a water-cooling manner.
If the cooled copper plate 30 does not exchange heat with the outside, the 1b surface 14 and the 2b surface 24 may affect the surface 1a surface 12 and the 2a surface 22. Accordingly, the black body 2 is difficult to heat to a desired temperature.
In order to perform correction on a thermal imaging camera at various temperatures, the above process may be performed while varying the predetermined temperature of a black body.
Although an apparatus and method for controlling the temperature of a black body has been described with reference to the specific embodiments, it is not limited thereto. Therefore, it will be readily understood by those skilled in the art that various modifications and changes can be made thereto without departing from the spirit and scope of the present invention defined by the appended claims.

Claims

1. An apparatus for controlling temperature of a black body, comprising:

a black body emitting radiant energy of infrared rays;

a first Peltier element adjacent to the black body, the first Peltier element having a 1a surface and a 1b surface that selectively emit or absorb heat;

a copper plate adjacent to the 1b surface;

a second Peltier element adjacent to the 2b surface, the second Peltier element having a 2a surface and a 2b surface that selectively emit or absorb heat;

a heat transfer member comprising a bent surface adjacent to the 2a surface, and an arm extending toward both ends of the black body to be adjacent to the both ends of the black body; and

a control unit controlling the 2a surface to emit heat simultaneously when the 1a surface emits heat, and the 2a surface to absorb heat simultaneously when the 1a surface absorbs heat,

wherein the second Peltier element has a through hole at the center thereof, and the apparatus further comprises a heat-emitting member contacting the copper plate to exhaust heat generated in the copper plate.

2. The apparatus of claim 1, wherein when the black body is cooled, the temperature of the 1a surface is lower than the temperature of the 2a surface.

3. The apparatus of claim 1, wherein when the black body is heated, the temperature of the 1a surface is higher than the temperature of the 2a surface.

4. (canceled)

5. The apparatus of claim 1, wherein the heat-emitting member comprises a heat-emitting plate connected to the copper plate, which performs heat exchange in a water-cooling manner or in an air-cooling manner.

6. A method for controlling temperature of a black body using the apparatus of claim 1 comprising:

measuring temperature of the black body emitting radiant energy of infrared rays;

determining whether the measured temperature is higher or lower than a predetermined temperature; and

emitting heat from a 1a surface adjacent to the black body and a 2a surface of a second Peltier element adjacent to a heat transfer member comprising an arm adjacent to both ends of the black body 2 when the measured temperature is lower than the predetermined temperature, and absorbing heat into the 1a surface and the 2a surface adjacent to the black body when the measured temperature is higher than the predetermined temperature.

7. The method of claim 6, wherein when heat is emitted from the 1a surface, the temperature of the 1a surface is lower than the temperature of the 2a surface, and when heat is absorbed into the 1a surface, the temperature of the 1a surface is higher than the temperature of the 2a surface.