infrared camera

Abstract

To provide an infrared camera that can easily measure the accurate temperature of an imaging target without providing means such as a mechanical shutter mechanism or cooling means.SOLUTION: An infrared camera comprises: an imaging unit 6 having a plurality of infrared detection elements 6a arranged on a two-dimensional plane; a lens 5 that focuses infrared rays emitted from an imaging target onto the imaging unit 6; an element temperature detection sensor 7 connected to the infrared detection element 6a and detecting the temperature of the infrared detection element 6a; and holding portions 2 and 3 that hold the lens 5 and also hold the imaging unit 6 directly or indirectly. The holding portions 2 and 3 are made of non-insulating material, and the lens 5 and the imaging unit 6 are connected via the holding portions 2 and 3 in a thermally coupled state.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an infrared camera having an imaging section configured by arranging a plurality of infrared detection elements on a two-dimensional plane. [Background technology]

[0002] Conventionally, an infrared camera has been proposed in which the imaging section is composed of a thermal, uncooled infrared detection element known as a bolometer (Patent Document 1). This infrared detection element changes its resistance value when it absorbs infrared rays, and outputs a voltage value corresponding to the amount of incident light when a current is passed through it. When an image of an object is captured, that is, when infrared rays emitted from the object are absorbed by the infrared detection element, a voltage value corresponding to the incident energy is output, and the temperature of the object can be calculated by calibrating the output voltage value based on the sensitivity obtained in advance.

[0003] It is known that the sensitivity of this infrared detection element varies from one element to another. Conventionally, generally, an image of an object at two different known temperatures T1 and T2, for example, a blackbody furnace (a device that approximates a blackbody), is captured, and the output V of each infrared detection element n obtained at that time is measured. n and the temperature T of the object to be imaged, the sensitivity of each infrared detection element n is calculated.

[0004] More specifically, the output V n The relationship between temperature T and output V1 at temperatures T1 and T2 is n ,V2 n From the two data points, the sensitivity coefficient a n and offset coefficient b n It is approximated by the following equation, which is a linear function using V n =a n ×T+b n Therefore, the temperature T of the object to be imaged can be calculated by the following formula: T=(V n -b n ) / a n =V n / an -b n / a n =V n ×A n +B n

[0005] Furthermore, even when the infrared detection element n absorbs infrared rays emitted from an object of the same temperature, its output V n Fig. 4 shows the relationship between the temperature Ft of the infrared detection element and the output V of the element when an image of an object at a predetermined temperature T is captured while the temperature Ft of the infrared detection element is changed. n As shown in FIG. 4, the element output V n fluctuates depending on the element temperature Ft.

[0006] Therefore, if the temperature of the infrared detection elements that make up the imaging unit fluctuates due to factors such as the ambient temperature, even when an image of an object having the same temperature is captured, the value output from each infrared detection element will fluctuate depending on the temperature of the infrared detection element, making it impossible to measure the accurate temperature of the object.

[0007] Furthermore, the lens for focusing infrared light onto the infrared detection element and the holding member that holds it each have a temperature, and infrared light corresponding to their temperature is radiated from these lenses and holding members toward the infrared detection element (background radiation). Therefore, if the temperature of the lens or holding member fluctuates due to fluctuations in the ambient temperature, the amount of infrared radiation radiated from these toward the infrared detection element (background radiation) will fluctuate, and in response, the value output from the infrared detection element will fluctuate. Thus, if the amount of background radiation fluctuates in this way, it will be impossible to accurately measure the temperature of the object being imaged. The offset coefficient b in the above equation n is determined under a predetermined environment, and its value fluctuates when the environment fluctuates.

[0008] Therefore, conventional infrared cameras have adopted a configuration such as that shown in Fig. 5. Specifically, this infrared camera 100 is composed of an imaging unit 103 having a plurality of infrared detection elements 103a arranged on a two-dimensional plane, a lens 102 that focuses infrared rays 110 emitted from an object to be imaged onto the imaging unit 103, a holding member 101 that holds the lens 102, a Peltier element 104 that cools the imaging unit 103, a processing board 105 that is connected to the imaging unit 103 with the Peltier element 104 in between, and a shutter 106 that is provided between the lens 102 and the imaging unit 103.

[0009] The holding member 101 is composed of a cylindrical member with both axial ends open, and the lens 102 is fixedly attached to one side of the holding member 101 so as to seal one opening of the holding member 101. The imaging unit 103 is provided within the holding member 101 with its sensing surface facing the lens 102, and the Peltier element 104 is adhered to its back surface. A processing board 105 connected to the imaging unit 103 with the Peltier element 104 sandwiched between them is fixed to the holding member 101.

[0010] In this infrared camera 100, the temperature of the infrared detection element 103a is adjusted to a constant value by the Peltier element 104. As described above, if the temperature of the infrared detection element 103a fluctuates due to factors such as the ambient temperature, the output value of the infrared detection element 103a fluctuates depending on the temperature of the infrared detection element 103a, even when an image of an object having the same temperature is captured, and the temperature of the object cannot be measured accurately. However, in this infrared camera 100, the infrared detection element 103a is adjusted to a constant temperature, so this problem does not occur.

[0011] In addition, in this infrared camera 100, only when the shutter 106 is open, infrared rays 110 emitted from the object to be imaged are collected by the image capturing unit 103 through the lens 102 and detected by the image capturing unit 103. At the same time, the temperature of the shutter 106 is detected by a temperature detection sensor as appropriate, and the offset coefficient b in the above formula is calculated according to the temperature.n As described above, if the amount of background radiation behind the lens 102 (the amount of infrared radiation radiated from the shutter 106 and the holding member 101 in the internal space 107) fluctuates, the value output from the infrared detection element 103a fluctuates, making it impossible to accurately measure the temperature of the object to be imaged. However, in this infrared camera 100, the temperature fluctuation of the shutter 106 is detected, and based on this, the fluctuation in the amount of background radiation is estimated, and the offset coefficient b in the above equation is calculated. n This solves the above problem caused by fluctuations in background radiation. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-193194 Summary of the Invention [Problem to be solved by the invention]

[0013] However, the conventional infrared camera 100 described above has the following problems.

[0014] In other words, the shutter 106 described above is composed of a plate having a mechanical shutter mechanism that opens and closes using electromagnetic force, and because it is a mechanical mechanism, it is prone to malfunction. Furthermore, naturally, there is a problem in that imaging by the infrared camera 100 can only be performed when the shutter 106 is open, making it impossible to continuously capture images of the object being imaged.

[0015] Furthermore, conventional infrared cameras 100 adjust the temperature of the imaging unit 103 using a Peltier element 104, but temperature control using the Peltier element 104 requires a considerable amount of power, which poses a problem in terms of power consumption, and the Peltier element 104 generates heat in the electrode portion on the opposite side to the cooling side, which poses a problem in that a mechanism is required to dissipate the generated heat. These problems have made it impossible to reduce the size of conventional infrared cameras 100.

[0016] The present invention has been made in consideration of the above-mentioned circumstances, and its object is to provide an infrared camera that can easily measure the accurate temperature of an object to be imaged without the need for a mechanical shutter mechanism or cooling means. [Means for solving the problem]

[0017] To solve the above problems, the present invention provides: an imaging unit having a plurality of infrared detection elements arranged on a two-dimensional plane; a lens that condenses infrared light emitted from an object to be imaged onto the imaging unit; an element temperature detection sensor connected to the infrared detection element to detect the temperature of the infrared detection element; an infrared camera including at least a holding part that holds the lens and directly or indirectly holds the imaging part, the holding portion is made of a non-insulating material, The lens and the imaging unit are connected to an infrared camera in a thermally coupled state via the holding unit.

[0018] In this infrared camera, the lens is held by a holding part made of a non-insulating material, in other words, a material with good thermal conductivity, and the imaging part is held directly or indirectly by the holding part, so that the lens and the imaging part are connected in a thermally coupled state via the holding part.

[0019] An infrared camera having the above configuration has good thermal conductivity between the lens, holding part, and imaging part, and as a result, the temperatures of these parts easily reach equilibrium and are maintained at a stable, constant temperature.

[0020] By maintaining the temperature of the imaging unit at a constant equilibrium temperature in this way, the values ​​output from each infrared detection element can be maintained at values ​​that do not fluctuate according to the temperature of the object being imaged, and by maintaining the temperatures of the lens and holding unit at a constant equilibrium temperature, the amount of infrared radiation (background radiation) radiated from the lens and holding unit to the imaging unit according to their temperatures can be maintained constant.

[0021] Thus, by maintaining the temperatures of the lens, holding unit, and imaging unit at a constant equilibrium temperature, it is sufficient to perform the calibration work once to calculate the calibration values ​​for calibrating the output from each infrared detection element according to the temperature of the imaging unit and the amount of background radiation, making it easy to perform calibrations based on these factors and enabling the accurate temperature of the object to be imaged to be measured.

[0022] Furthermore, since the infrared camera according to the present invention does not have a mechanical shutter mechanism, it can continuously capture images of the object to be imaged, and furthermore, since it does not have means such as a shutter mechanism or cooling means, it can be made smaller.

[0023] In the above infrared camera, the holding portion is composed of a cylindrical member having both axial ends open, the lens is fixedly attached to one side of the holding portion so as to seal one opening of the holding portion, The imaging section may be connected in close contact with the other side of the holding section so as to seal the other opening of the holding section.

[0024] With this type of infrared camera, the lens and imaging unit are tightly connected to the holding unit, allowing for better thermal coupling between the lens, imaging unit, and holding unit, and as a result, the temperatures of these units can be maintained more stably and constantly.

[0025] Furthermore, in the infrared camera of the above aspect, The imaging unit may be connected to the holder via a thermally conductive material, which provides a more favorable thermal connection between the imaging unit and the holder, thereby enabling the temperatures of the lens, imaging unit, and holder to be maintained at a more stable and constant state.

[0026] Examples of the thermally conductive material include, but are not limited to, resins such as silicone, acrylic, and polyolefin. The thermally conductive material may be in the form of a sheet, but is not limited to this. The thermally conductive material preferably has a thermal conductivity of 0.5 W / mK or more, and more preferably has a thermal conductivity of 1.5 W / mK or more.

[0027] The holding portion is preferably made of a metal material, for example, an aluminum alloy, but is not limited to this. [Effects of the Invention]

[0028] As described above, the infrared camera according to the present invention provides good thermal conductivity between the lens, holder, and imaging unit, resulting in their temperatures being in equilibrium and maintained at a stable, constant temperature. By achieving equilibrium among the lens, holder, and imaging unit, it is sufficient to perform a calibration operation only once to calculate a calibration value for calibrating the output from each infrared detection element in accordance with the temperature of the imaging unit and the amount of background radiation. This facilitates calibration based on these factors and enables accurate temperature measurement of the object being imaged.

[0029] Furthermore, since the infrared camera according to the present invention does not have a mechanical shutter mechanism, it can continuously capture images of the object to be imaged, and furthermore, since it does not have means such as a shutter mechanism or cooling means, it can be made smaller. [Brief explanation of the drawings]

[0030] [Figure 1] 1 is a block diagram showing an infrared camera according to an embodiment of the present invention; [Figure 2] 1 is an explanatory diagram showing the structure of an infrared camera according to an embodiment of the present invention; [Figure 3] 10A and 10B are explanatory diagrams showing the structure of an infrared camera according to another embodiment of the present invention. [Figure 4] FIG. 1 is an explanatory diagram for explaining problems of the conventional art. [Figure 5] FIG. 1 is an explanatory diagram showing the structure of a conventional infrared camera. DETAILED DESCRIPTION OF THE INVENTION

[0031] Specific embodiments of the present invention will be described below with reference to the drawings. Fig. 1 is a block diagram showing an infrared camera according to one embodiment of the present invention, and Fig. 2 is an explanatory diagram showing the structure of the infrared camera according to this embodiment.

[0032] As shown in Figures 1 and 2, the infrared camera 1 of this example is composed of a cylindrical housing 2 that is open at both axial ends, a lens 5 that is tightly attached and fixed to one side of the housing 2 so as to seal one of the openings of the housing 2, a ring-shaped joining member 3 with a hook-shaped cross section that is fixed to the inner surface of the housing 2 near the opening on the other side, an imaging unit 6 that is joined to the joining member 3 via a thermally conductive material 4, an element temperature detection sensor 7 that is connected to the imaging unit 6 and detects its temperature, and a processing board (data processing unit) 8 that is attached to the imaging unit 6 across the element temperature detection sensor 7.

[0033] The imaging unit 6 includes a plurality of infrared detection elements 6a arranged in rows and columns on a two-dimensional plane, with their sensing surfaces facing the lens 5 at predetermined intervals. The imaging unit 6 is accommodated within the ring of the joining member 3, and the processing board 8 is fixed to the lower surface of the joining member 3, whereby the upper surface of the imaging unit 6 is joined to the joining member 3 via the thermally conductive material 4. The infrared detection elements 6a are thermal, uncooled elements known as bolometers, and each infrared detection element 6a outputs a voltage value corresponding to the amount of incident light and inputs it to the data processing unit 8.

[0034] The element temperature detection sensor 7 is connected to the rear surface of the imaging unit 6, opposite to the sensing surface, and inputs data relating to the detected temperature of each infrared detection element 6a to the data processing unit 8. The element temperature detection sensor 7 detects the temperature of the infrared detection elements 6a as a whole.

[0035] As described above, the lens 5 is provided on one opening side of the housing 2, receives infrared rays 10 emitted from an object to be imaged, and collects the light on the image capturing unit 6.

[0036] The housing 2 and the joining member 3 constitute a holding portion and can be made of a non-insulating material, for example, a metal material such as an aluminum alloy. However, the material is not limited to this aluminum alloy, and can be made of a metal material or other material as long as it has good thermal conductivity.

[0037] In the infrared camera 1 of this example, the lens 5 is fixedly attached to the housing (holding portion) 2, and the imaging portion 6 is joined to the joining member (holding portion) 3 via a thermally conductive material 4. As a result, the lens 5 and imaging portion 6 are connected in a thermally coupled state via the housing 2, which is the holding portion, and the joining member 3.

[0038] Examples of the thermally conductive material include, but are not limited to, resins such as silicone, acrylic, and polyolefin. The thermally conductive material may be in the form of a sheet, but is not limited to this. The thermally conductive material preferably has a thermal conductivity of 0.5 W / mK or more, and more preferably has a thermal conductivity of 1.5 W / mK or more.

[0039] The infrared camera 1 of this example having the above configuration has good thermal conductivity between the lens 5, housing 2, joining member 3, and imaging unit 6, and as a result, the temperatures of these elements easily reach equilibrium and are maintained at a stable, constant temperature.

[0040] By maintaining the temperature of the imaging unit 6 at a constant equilibrium temperature in this manner, the values ​​output from the infrared detection elements 6a can be maintained at values ​​that do not fluctuate according to the temperature of the object being imaged. Furthermore, by maintaining the temperatures of the lens 5, the housing 2, and the joining member 3 at a constant equilibrium temperature, the amount of infrared radiation (amount of background radiation) radiated from the lens 5, the housing 2, and the joining member 3 to the imaging unit 6 in accordance with their temperatures can be maintained constant within the internal space 9.

[0041] Thus, by maintaining the temperatures of the lens 5, the housing 2, the joining member 3, and the imaging unit 6 at a constant equilibrium temperature, it is sufficient to perform the calibration work only once to calculate the calibration value for calibrating the output from each infrared detection element 6a according to the temperature of the imaging unit 6 and the amount of background radiation, which makes it easy to perform the calibration due to these factors and enables the accurate temperature measurement of the object to be imaged.

[0042] Furthermore, the infrared camera 1 of this example does not have a mechanical shutter mechanism as in the conventional case, so it can continuously capture images of the object to be imaged, and furthermore, since it does not have means such as a shutter mechanism or cooling means, it can be made smaller.

[0043] Although one embodiment of the present invention has been described above, the specific aspects that the present invention can adopt are not limited to the above-mentioned example.

[0044] For example, in the above example, the thermal conductivity (thermal bonding) between the imaging unit 6 and the bonding member 3 is improved by providing a thermally conductive material 4 in the gap between the upper surface of the imaging unit 6 and the bonding member 3. However, this is not limited to this embodiment, and as shown in FIG. 3, an infrared camera 1' may be configured in which a thermally conductive material 4' is provided in the gap between the upper surface and outer peripheral surface of the imaging unit 6 and the bonding member 3. In this way, the thermal conductivity (thermal bonding) between the imaging unit 6 and the bonding member 3 can be further improved. Note that in FIG. 3, the same components as those in FIG. 2 are denoted by the same reference numerals.

[0045] Alternatively, if the thermal conductivity (thermal bonding) between the imaging unit 6 and the joining member 3 is sufficient, an embodiment can be adopted in which the thermally conductive material 4 is not provided as in Figure 2, and the imaging unit 6 and the joining member 3 are closely attached to each other without any gaps. [Explanation of symbols]

[0046] 1. Infrared camera 2 Housing (holding part) 3 Joint member (holding part) 4. Thermally conductive materials 5 Lenses 6. Imaging unit 6a Infrared detector 7 Element temperature detection sensor 8 Processing board (data processing unit) 9. Interior Space 10. Infrared

Claims

1. an imaging unit having a plurality of infrared detection elements arranged on a two-dimensional plane; a lens that condenses infrared light emitted from an object to be imaged onto the imaging unit; an element temperature detection sensor connected to the infrared detection element to detect the temperature of the infrared detection element; an infrared camera including at least a holding part that holds the lens and directly or indirectly holds the imaging part, the holding portion is made of a non-insulating material, The infrared camera is characterized in that the lens and the imaging unit are connected in a thermally coupled state via the holding unit.

2. the holding portion is composed of a cylindrical member having both axial ends open, the lens is fixedly attached to one side of the holding portion so as to seal one opening of the holding portion, 2. The infrared camera according to claim 1, wherein the imaging unit is connected to the other side of the holding unit in close contact with the other opening of the holding unit so as to seal the other opening.

3. 2. The infrared camera according to claim 1, wherein the imaging unit is connected to the holding unit via a thermally conductive material.

4. 4. The infrared camera according to claim 1, wherein the holding portion is made of a metal material.

Images