JP2005337772A - Infrared imaging apparatus having sensibility correction mechanism of infrared detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve a compact and lightweight sensitivity correction mechanism of a simplified constitution in an infrared imaging apparatus having a sensitivity correction mechanism of an infrared detector. <P>SOLUTION: The infrared imaging apparatus is provided with infrared detecting elements 12 and 13 corresponding to a plurality of optical systems. A rotating base plate 11 is arranged at a position which intersects with an infrared incident optical path of each optical system. The rotating base plate 11 is provided with a plurality of through holes for passing infrared incident light of each optical system and temperature reference plates 16, 32, 17, and 31 for correcting the sensitivity of the infrared detecting elements. The rotating base plate 11 is rotated to arrange the through holes at positions which intersect with the infrared incident optical path of each optical system when infrared images are taken and arrange the temperature reference plates at positions which intersect with the infrared incident optical path of each optical system in such a way as to oppose the temperature reference plates to the infrared detecting elements when the sensitivity of the infrared detecting elements is corrected. Sensitivity correction data on the side of low temperatures (or on the side of high temperatures) is measured from the infrared detecting elements 12 and 13, and temperature sensitivity correction data on the opposite side is measured by rotating the rotating base plate 11 by 180 degrees. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an infrared imaging device having a sensitivity correction mechanism for an infrared detector. The configuration of the infrared imaging apparatus is shown in FIG. The infrared imaging device collects infrared energy 51 radiated by an object with an infrared lens 52, detects an infrared image formed on the light receiving surface of the infrared detection element 54 of the infrared detector 53 with the infrared detection element 54, and outputs the infrared image. The current (or voltage) is amplified and A / D converted by the amplifying / AD converting circuit 58 and displayed on the monitor 60 via the signal processing circuit 59 as an image. In the infrared detector 53, a plurality of infrared detection elements 54 are arranged on a substrate 55 mounted on a base 56, and a circulation cooler 57 is further mounted on the base 56.

  Although there are many types of operation of infrared imaging devices, one example of operation is night monitoring, which is impossible to visually recognize, and this is because the optical system with appropriate magnification and sensitivity performance / resolution for each operation system The detection element is used for detecting, identifying and monitoring a target object in the dark.

  The sensitivity correction of the infrared detector 53 is performed in order to improve the deterioration of the image quality of the infrared imaging device due to the dark current component and sensitivity variation of the infrared detection element 54, and is particularly effective in an infrared detector having a plurality of infrared detection elements. Yes, image quality is greatly improved by sensitivity correction.

  As shown in FIG. 6, the sensitivity characteristic of the infrared detection element does not become a reception sensitivity characteristic linear with respect to the object temperature. That is, the receiving sensitivity characteristic of the infrared detection element is not proportional to the infrared energy emitted from each target object, but has a quadratic curve characteristic with respect to the infrared energy emitted from each target object. Furthermore, even if uniform infrared energy is received, the current (or voltage) output from each infrared detection element is non-uniform between pixels due to variations in sensitivity of each infrared detection element.

  If an infrared imaging device is used without correcting this variation in reception sensitivity, the displayed image will be of low quality. Therefore, as shown in FIG. 7, two types of temperature reference plates (on the low temperature side of normal temperature) having a uniform infrared radiation surface treated with a black body in front of the infrared incident optical path where the infrared detector 53 enters the infrared energy 51. And a high-temperature side reference heat source plate) 62 are mechanically inserted, the output current (or voltage) of each infrared detection element 54 is measured, and the steady-state deviation of each infrared detection element 54 is corrected.

  The temperature reference plate 62 is inserted in front of the infrared detector 53 only when sensitivity correction is performed by the sensitivity correction mechanism 61 driven by the drive circuit 63, and the temperature reference plate 62 is retracted from the infrared incident optical path during normal photographing. Moved to. As the temperature reference plate 62, a low-temperature and high-temperature reference heat source plate is necessary in order to perform sensitivity correction by measuring two points on the low-temperature side and the high-temperature side of normal temperature (near the background temperature).

  When performing sensitivity correction, the temperature reference plate 62 is inserted into the optical path of the infrared optical system. First, a high temperature reference heat source plate is inserted, high temperature data is acquired, and stored in a high temperature frame memory. Next, a low temperature reference heat source plate is inserted, low temperature data is acquired, and stored in a low temperature frame memory.

  The acquisition time of high-temperature or low-temperature data is a period in which output data from all detection elements of the infrared detector is acquired, and requires a time of 1 frame (1/30 second) at the shortest. By increasing the number, more stable sensitivity correction can be performed. Sensitivity correction calculation is performed based on data stored and held in the high-temperature frame memory and the low-temperature frame memory.

Hereinafter, the sensitivity correction calculation will be described. Difference temperature data is calculated for each detection element from the high temperature data and the low temperature data acquired by inserting two types of temperature reference plates into the incident optical path.
S11 (ΔT) = S11 (T1) −S11 (T2) (Formula 1-11)
S12 (ΔT) = S12 (T1) −S12 (T2) (Formula 1-12)
:
Slm (ΔT) = Slm (T1) −Slm (T2) (Formula 1-lm)

  Here, l is the number of horizontal pixels, m is the number of vertical pixels, T1 is the high temperature side temperature, T2 is the low temperature side temperature, ΔT is the difference temperature, Sij (T1), Sij (T2), Sij (ΔT) are respectively The high-temperature data, the low-temperature data, and the difference temperature data of the horizontal pixel position i (1 ≦ i ≦ l) and the vertical pixel position j (1 ≦ j ≦ m).

Next, an average value S (ΔT) of the difference temperature data obtained by (Equation 1-11) to (Equation 1-lm) is obtained by the following calculation formula.
S (ΔT) = ΣSlm (ΔT) / n (Expression 2)
Here, n is the total number of pixels.

Temperature correction coefficients k (11) to k (lm) for each detection element based on the difference temperature data obtained by (Expression 1-11) to (Expression 1-lm) and the difference temperature data average value obtained by (Expression 2) Is obtained by the following calculation formula.
k (11) = S11 (ΔT) / S (ΔT) (Equation 3-11)
k (12) = S12 (ΔT) / S (ΔT) (Formula 3-12)
:
k (lm) = Slm (ΔT) / S (ΔT) (Formula 3-lm)

The temperature correction coefficients k (11) to k (lm) obtained by the above (Expression 3-11) to (Expression 3-lm) are multiplied by the output data S11 to Slm of each detection element as shown in the following expression, and the sensitivity is obtained. The corrected output data S11 ′ to Slm ′ are obtained.
S11 ′ = S11 × k (11) (Formula 4-11)
S12 ′ = S12 × k (12) (Formula 4-12)
:
Slm ′ = Slm × k (lm) (Formula 4-lm)

  In FIG. 7, the signal processing circuit 59 converts the infrared image detection data after the sensitivity correction into a display format suitable for the television scanning method or the like, and sends a signal for displaying the captured infrared image on the monitor 10. The present invention relates to a sensitivity correction mechanism for improving deterioration in image quality due to dark current components or sensitivity variations of an infrared detection element in such an infrared imaging device.

  In general, infrared atmospheric transmittance varies greatly depending on the wavelength. Infrared wavelength bands used in infrared imaging devices include a long wavelength band of 8 to 12 μm and a short wavelength band of 3 to 5 μm. The short wavelength band is used in summer when the moisture in the atmosphere is relatively high. In many seasons, observations are often made using the long wavelength band.

  Infrared detectors are two-dimensionally arrayed with various semiconductor infrared detectors, but there is no highly sensitive infrared detector that can be used for both long and short wavelength bands. A configuration is employed in which infrared detection elements corresponding to the wavelength band and the short wavelength band are used separately.

  When observing a distant object, a high magnification optical system is provided for each of the short wavelength band and the long wavelength band. In the case of an infrared imaging device having only a high-magnification optical system, since only a narrow viewing angle can be searched, it is difficult to search for an object over a wide range. Therefore, a low-magnification optical system is also provided for a wide range search. That is, a high-magnification optical system and a low-magnification optical system corresponding to the long wavelength band and the short wavelength band are provided.

  A conventional two-wavelength optical system sensitivity correction mechanism is shown in FIG. In the figure, (a) is the overall layout of the two-wavelength optical system and the sensitivity correction mechanism, (b) is a plan view of the sensitivity correction mechanism as viewed from above, and (c) is a side view of the sensitivity correction mechanism as viewed from the side. Is shown. As shown in FIG. 2A, the two-wavelength optical system infrared imaging device includes an a-wavelength band optical system 61 and a b-wavelength band optical system 62, and in front of the infrared detection elements 63 and 64 of the respective optical systems. Sensitivity correction mechanisms 65 and 66 are provided (downward in the illustrated position).

  Since the sensitivity correction mechanisms 65 and 66 provided in the respective optical systems 61 and 62 have the same structure, the detailed configuration of the sensitivity correction mechanism 65 of the a wavelength band optical system 61 is shown in FIGS. The detailed configuration of the sensitivity correction mechanism 66 of the b wavelength band optical system 62 is not shown, but the configuration is simply a left-right reversal of the configuration shown in (b) and (c) of FIG. is there.

  When performing sensitivity correction of the detection elements 63 and 64 in the infrared detector of the optical system of each wavelength band, the drive motor 68 is driven by a command signal from the sensitivity correction drive circuit 67, the sensitivity correction base plate 69 is rotated, After the high-temperature temperature reference plate 70 is inserted into the infrared incident optical path, the infrared radiation energy of the temperature reference plate 70 is incident on the infrared detection element 63, and each detection element when receiving the radiation energy from the temperature reference plate 70 is received. Measure the output of.

  Next, after the low temperature reference plate 71 is inserted into the infrared incident optical path by a similar sensitivity correction mechanism (not shown), the output of each infrared detection element when the radiation energy from the temperature reference plate 71 is received is measured. To do. Then, by performing output correction corresponding to sensitivity variations at high and low temperatures, the output data is made uniform and sent to the monitor, and the infrared image is processed into uniform image quality.

  Next, conventional sensitivity correction mechanisms and cooling structures using Peltier elements are shown in FIGS. FIG. 9 shows a configuration viewed from the side of a conventional two-wavelength optical infrared imaging device. In FIG. 9, 101 is a high-magnification objective reflection optical system, 102 is a plane mirror, 104 is a long-wavelength band imaging refractive optical system, 106 is a long wavelength band detecting element, 107 is a low-magnification objective refracting optical system, 108 is a temperature reference plate for high temperature, 110 is a rotary table, 111 is a slide table, 115 is a primary reflecting mirror, 116 is a secondary reflecting mirror, 117 Is a condensing / refracting optical system, 118 is an optical substrate, and 119 is a rotation mechanism.

  FIG. 10 shows the configuration of the two-wavelength optical infrared imaging device of FIG. 9 as viewed from above. The same reference numerals as those in FIG. 9 denote the same components, 103 denotes a short wavelength band imaging refractive optical system, and 105 denotes a short configuration. A wavelength band detecting element 109 is a temperature reference plate for low temperature. FIG. 11 shows a configuration including a short wavelength band imaging / refractive optical system 103, a short wavelength band detecting element 105, and the like. The optical lens constituting the refractive optical system is shown in a simplified manner.

  The high-magnification objective reflection optical system 101 includes a concave primary reflecting mirror 115 and a planar secondary reflecting mirror 116, and reflects the infrared light collected by the primary reflecting mirror 115 upward by the secondary reflecting mirror 116. After the primary image formation, the light is condensed by the condensing / refractive optical system 117 and is incident on the flat mirror 102.

  After being reflected by the plane mirror 102 to generate secondary image formation, it is incident on the long wavelength band imaging refractive optical system 104 or the short wavelength band imaging refractive optical system 103. Then, on the upper part of the high-magnification objective reflection optical system 101, a long-wavelength band imaging refractive optical system 104 and a long-wavelength band detection element 106, a short-wavelength band imaging refractive optical system 103 and a short-wavelength band detection element 105, The low-magnification objective refracting optical system 107 is disposed so that the optical axes thereof are substantially parallel.

  The low-magnification objective refracting optical system 107 and the long wavelength band imaging refracting optical system 104 are arranged so as to coincide with each other. As described above, the long wavelength band detecting element 106 and the short wavelength band detecting element 105 use a semiconductor element having high detection sensitivity in each wavelength band, and cooling is omitted in order to improve infrared detection sensitivity. Cool by means.

  Further, the flat mirror 102 is supported on the rotary table 110 by a support mechanism (not shown) together with the rotation mechanism 119, and the high-temperature temperature reference plate 108 and the low-temperature temperature reference plate 109 are fixed at orthogonal positions. The rotary table 110 is rotated in the direction of the arrow a about the axis d (see FIG. 9) by a motor or the like (not shown), so that the high wavelength objective reflection optical system 101 has a long wavelength band. Switching between the imaging refractive optical system 104 and the short wavelength band imaging refractive optical system 103 is performed.

  Further, when the slide table 111 is slid in the direction of arrow A in FIG. 10 by a motor or the like (not shown) and the plane mirror 102 on the rotary table 110 is set to the dotted line position, the low magnification objective refractive optical system The flat mirror 102, the temperature reference plate, etc. that existed between the optical axis 107 and the optical axis of the long wavelength band imaging refractive optical system 104 are moved, and the secondary reflecting mirror 116 of the high-magnification objective reflective optical system 101 is moved. Infrared rays through are blocked. Therefore, infrared rays that have passed through the low-magnification objective refracting optical system 107 can be incident on the long wavelength band imaging refractive optical system 104 and imaged by the long wavelength band detecting element 106.

  In FIG. 9, when the plane mirror 102 is rotatably supported by the rotation mechanism 119, is rotated in the direction of the arrow b about the axis c, and the plane mirror 102 is moved to the dotted line position, the temperature reference plate for high temperature is used. 108 can be put in the field of view of the long wavelength band detecting element 106 to correct the high temperature side of the long wavelength band detecting element 106.

  Further, the low-temperature temperature reference plate 109 enters the field of view of the short wavelength band detecting element 105, and the low temperature side correction of the short wavelength band detecting element 105 can be performed. From this state, the rotary table 110 is rotated by 90 degrees, and the low temperature side temperature reference plate 109 is placed in the field of view of the long wavelength band detecting element 106 to correct the low temperature side.

  Similarly, the high temperature side of the short wavelength band detecting element 105 can be corrected by rotating the rotary table 110 so that the high temperature temperature reference plate 109 enters the field of view of the short wavelength band detecting element 105. Therefore, temperature correction of the short wavelength band detecting element 105 and the long wavelength band detecting element 106 can be performed at any time.

  FIG. 12 is an explanatory diagram of a conventional temperature reference plate. The same reference numerals as those in the above-described respective drawings indicate the same components, 112 denotes a high-temperature Peltier element, 113 denotes a low-temperature Peltier element, and 114 denotes a heat radiating fin. FIG. 12A shows a high temperature reference plate 108 and a low temperature reference plate 109 for pupil positions (long wavelength band detection of the long wavelength band imaging refractive optical system and the short wavelength band imaging refractive optical system, respectively. (The imaging range by the element 106 and the short wavelength band detecting element 105) is arranged at a position orthogonal to the rotary table 110, and by the rotation of the rotary table 110, the high-temperature temperature reference plate 108 and the low-temperature temperature reference plate 109. And the temperature correction process is executed.

  As shown in FIG. 12B, the high temperature temperature reference plate 108 and the low temperature temperature reference plate 109 are disposed in contact with the high temperature Peltier element 112 and the low temperature Peltier element 113, respectively. The high temperature reference plate 108 and the low temperature reference plate 109 maintain the high temperature reference temperature and the low temperature reference temperature by current control by a control circuit (not shown) of the Peltier device 112 and the low temperature Peltier device 113. The heat radiation fins 114 dissipate heat from the back surfaces of the Peltier elements 112 and 113.

  As described above, the sensitivity correction mechanism using the conventional Peltier element has a structure in which the temperature reference plates 108 and 109 and the radiation fins 114 in contact with the high-temperature and low-temperature Peltier elements 112 and 113 are rotated. The rotary table 110 is mounted on the table 110 and rotates by being controlled by a drive motor and a control card. In a state where sensitivity correction is not performed, the rotary table 110 is slid in the direction of A in FIG. 10 by the slide table 111, and the entire sensitivity correction mechanism is retracted from the infrared light path.

  Further, the rotary table 110 is a part of a visual field switching mechanism that also has a rotating mirror drive. The conventional sensitivity correction mechanism integrates a visual field switching mechanism and a sensitivity correction mechanism to switch an optical system and a temperature reference for sensitivity correction. Although the structure is also used as a mechanism for switching the insertion of the plate, the scale of the parts to be driven is larger than that of the sensitivity correction mechanism alone, and the structure is complicated. A highly accurate movement control structure is required.

  However, unlike the optical system switching mechanism, the temperature reference plate insertion mechanism for sensitivity correction is not affected by optical axis misalignment caused by poor reproducibility of the lens position. High-precision movement control is not necessary.

There are the following patent documents as prior art documents related to the present invention.
JP 2003-78786 A Japanese Patent Laid-Open No. 04-285825 Japanese Patent No. 2644822 JP 2003-156391 A

  In the conventional example shown in FIG. 8, it is necessary to provide a sensitivity correction mechanism for individually inserting the high and low temperature reference plates 70 at appropriate positions facing the infrared detection element 63 in each optical system. It has become a factor that obstructs the downsizing and weight reduction of the device due to the increase in complexity and size. In addition, the sensitivity correction base plate 69 is not circular due to the limitation of mounting space, but is chopper-shaped, and a weight for the balancer is attached to adjust the center of gravity to the rotation axis. It was difficult to reduce the overall size and weight.

  Further, when the temperature reference plate 109 for low temperature is cooled using a Peltier element as in the conventional examples shown in FIGS. 9 to 12, since the back side of the Peltier element generates heat, a cooling mechanism for cooling the generated heat is provided. There is a need. Since the conventional sensitivity correction mechanism and cooling mechanism shown in FIGS. 9 to 12 are integrated with the visual field switching mechanism, the overall structure of the visual field switching mechanism that requires a precise position control mechanism is increased in size and cost. It was supposed to bring an increase.

  In addition, since the conventional sensitivity correction mechanism and cooling mechanism are equipped with heat radiation fins in the Peltier element, the cooling air from the nearby cooling fan can easily take the heat of the temperature-controlled temperature reference plate, and the reference temperature is stable. It had the disadvantage of being difficult. Further, when a large Peltier element is used, it is essential to have a cooling structure with high cooling efficiency, and a cooling structure that is small and lightweight and has high cooling efficiency has been required.

  An object of the present invention is to reduce the size and weight of a sensitivity correction mechanism of an infrared imaging device. It is another object of the present invention to efficiently transfer heat between the temperature reference plate and the Peltier element.

  The infrared imaging device of the present invention is (1) an infrared imaging device provided with an infrared detector having a plurality of infrared detection elements corresponding to a plurality of optical systems, and intersects an infrared incident optical path to the infrared detector of each optical system. A rotation base plate disposed at a position, and a drive mechanism that rotates the rotation base plate, and a plurality of infrared incident light beams to the infrared detectors of the optical systems are passed through the rotation base plate. A passage hole and a temperature reference plate for correcting the sensitivity of the infrared detection element are provided, and the drive mechanism rotates the rotation base plate, and the infrared passage of each optical system passes through the passage hole when photographing an infrared image. It is arranged at a position intersecting with the incident optical path, and at the time of correcting the sensitivity of the infrared detecting element, the temperature reference plate is arranged at a position intersecting with the infrared incident optical path of each optical system to block the infrared incident light and the infrared It characterized in that for opposing the temperature reference plate on the outlet device.

  (2) The temperature reference plate is disposed on the front and back surfaces of the rotating base plate so as to overlap each other as a pair of high and low temperature reference plates with a Peltier element interposed therebetween. A pair of temperature reference plates for a plurality of locations of the rotating base plate, and the high temperature side and the low temperature side of each of the pair of temperature reference plates arranged at the plurality of locations are respectively connected to the front surface and the back surface of the rotating base plate. It is characterized by being arranged in the opposite direction.

(3) The present invention is characterized in that a radiating pin fin is attached to the rotating base plate, and a cooling fan that blows cool air to the radiating pin fin is provided as an integral structure with the rotating base plate.
(4) The rotation mechanism so that the center of gravity of the rotation mechanism unit including at least the passage hole and the temperature reference plate arranged on the rotation base plate is point-symmetric about the rotation axis of the rotation base plate. The member of the part has been arrange | positioned.
(5) A positioning and fixing mechanism including an engaging mechanism between a locking groove and a protrusion is provided so that the rotation of the rotating base plate is locked at a predetermined position.

  The sensitivity correction mechanism of the present invention can be applied to an optical system in a plurality of wavelength bands (such as mid-infrared or far-infrared) by rotating the temperature correction mechanism of an integral structure in which a temperature reference plate is disposed on a rotating base plate. Since the temperature correction mechanism can be shared, there is no need to install a sensitivity correction mechanism individually for each of the plurality of optical systems, the number of electrical circuits, the number of mechanism parts, and the mounting space on the system are reduced. Miniaturization, weight reduction, and cost reduction can be achieved.

  In addition, a high-temperature temperature reference plate and a low-temperature temperature reference plate are superposed on the front and back surfaces of the rotating base plate with a Peltier element interposed therebetween, and the high-temperature side and the low-temperature side of the temperature reference plate are By arranging the plurality of temperature reference plates on the opening base plate so that the front and back surfaces of the rotating base plate are opposite to each other, heat absorption and exhaust heat can be efficiently performed.

  In addition, a Peltier element for setting the temperature reference plate to the reference temperature is mounted on the rotating base plate, the rotating base plate is provided with a cooling pin fin with high heat dissipation efficiency, and a forced air cooling fan is provided on the rotating base plate. By integrating the rotating base plate and the heat dissipation structure, the heat dissipation component can be reduced in size and weight, and it is not necessary to separately install and assemble the rotation mechanism and the cooling mechanism, thereby facilitating assembly.

  Further, the center of gravity of the rotation mechanism portion including the passage hole through which infrared incident light of each optical system disposed on the rotation base plate passes and the temperature reference plate described above is symmetric with respect to the center of the rotation base plate. That is, by configuring the center of gravity of the rotation mechanism to be completely coincident with the center of the motor shaft, which is the drive shaft, the drive load is reduced, and a small and light drive motor can be employed. The fixed position of the mechanism part is less affected by disturbances such as vibration and impact, and the entire apparatus can be reduced in size and weight, reduced in power consumption, and improved in environmental resistance.

  In addition, when the sensitivity correction is not performed so that the rotation mechanism is not affected by disturbances such as vibrations and impacts, the rotation mechanism is provided with a positioning fixing mechanism that locks the rotation mechanism at a predetermined position. Since the drive control can be turned off and the power input to the drive motor can be cut, the power consumption can be reduced, the life of the motor can be extended, and the reliability can be improved.

  FIG. 1 shows the sensitivity correction mechanism of the present invention. In the figure, 1 is an a wavelength band optical system, 2 is a b wavelength band optical system, 3 is a drive mechanism unit, 4 is a rotation mechanism unit, 5 is a drive motor, 6 is a potentiometer, 7 is a motor shaft, and 8 is a potentiometer shaft. , 9 is the first gear, 10 is the second gear, 11 is the rotating base plate, 12 is the a wavelength band detecting element, 13 is the b wavelength band detecting element, 14 is the a wavelength band low temperature side Peltier element, 15 is a Wavelength band high temperature side Peltier element, 16 a wavelength band low temperature side temperature reference plate, 17 a wavelength band high temperature side temperature reference plate, 18 cooling fan, 19 heat dissipation pin fin, 20 upper lid, 21 a wavelength band Optical axis center, 22 b wavelength band optical axis center, 23 passage hole, 24 harness, 25 interface connector, 26 plunger, 27 plunger bearing, 28 b wavelength band low temperature side Peltier element, 29 b wavelength High temperature side Peltier element , 30 is a monitor, 31 is a b wavelength band low temperature side temperature reference plate, 32 is a b wavelength band high temperature side temperature reference plate, 33 is a spring, 34 is a ball, 35 is an a wavelength band infrared detector, and 36 is an a wavelength band infrared. A detector, 37 is an AD conversion circuit, and 38 is a bearing.

  The sensitivity correction mechanism of the present invention is installed at a site that can be optically and physically shared and mounted on the optical systems 1 and 2 in the a wavelength band and the b wavelength band. The sensitivity correction mechanism according to the present invention is roughly divided into a drive mechanism unit 3 serving as a fixed part and a rotation mechanism unit 4 serving as a rotation part. The configuration of each part will be described below.

  The drive mechanism unit 3 includes a drive motor 5 for driving the rotation mechanism unit 4, a potentiometer 6 for detecting the rotation angle, a motor shaft 7 directly connected to the rotation mechanism unit, a potentiometer shaft 8, and rotation transmission of each axis. The first gear 9 for the motor, the second gear 10 (reduction ratio 1: 1), and a ball bearing 38 for holding them. The potentiometer shaft 8 uses a gear having a backlash-less function for the second gear 10 in order to remove a backlash detection error due to gear transmission with respect to the motor shaft 7.

  Next, the configuration of the rotation mechanism unit 4 will be described. The rotation mechanism unit 4 includes a rotation base plate 11 directly connected to the motor shaft 7, and the rotation base plate 11 is paired with a first low temperature side temperature reference plate 16 and a first high temperature side temperature reference plate 32. Are arranged so that the front surface and the back surface are back to back, and the second low temperature side temperature reference plate 16 and the first high temperature side temperature reference plate 32 are rotated 180 degrees from the second position. The high temperature side temperature reference plate 17 and the second low temperature side temperature reference plate 31 are paired so as to be back to back on the front surface and the back surface.

  At this time, the first low temperature side temperature reference plate 16 and the second high temperature side temperature reference plate 17 are arranged on the same surface (the lower surface in the figure), and the first high temperature side temperature reference plate 32 and The second bass-side temperature reference plate 31 is disposed on the opposite surface (upper surface in the figure). By doing so, the first low temperature side temperature reference plate 16 and the second low temperature side temperature reference plate 31 are simultaneously applied to the optical system detection elements 12 and 13 in the a wavelength band and the b wavelength band as shown in the figure. The first high temperature side temperature reference plate 32 and the second high temperature side temperature reference plate 17 are simultaneously opposed to the optical system detection elements 12 and 13 at a position where the rotation base plate 11 is rotated 180 degrees. The sensitivity correction can be performed at the same time for the a wavelength band optical system 1 and the b wavelength band optical system 2.

  Between the first low temperature side temperature reference plate 16 and the first high temperature side temperature reference plate 32 and the rotating base plate 11, a first low temperature side Peltier element 14 and a first high temperature side Peltier element 29 are provided. Are inserted between the second low temperature side temperature reference plate 31 and the second high temperature side temperature reference plate 17 and the rotary base plate 11, respectively. A high temperature side Peltier element 15 is inserted.

  The aforementioned low temperature side / high temperature side temperature reference plates 16, 31/17, 32 are for irradiating the detection elements 12, 13 uniformly with thermal conduction of the change temperatures of the Peltier elements 14, 28/15, 29, respectively. It is. Further, a cooling fan 18 is provided on the rotating base plate 11 in order to suppress a temperature rise of the rotating base plate 11 due to heat generated by the Peltier element.

  In order to efficiently dissipate the heat generated by the Peltier element by the cooling fan 18, the cooling air discharged from the cooling fan 18 flows at high speed and efficiently through the heat dissipating pin fins 19 provided on the rotating base plate 11. 20 is provided, and the space between the rotating base plate 11 and the upper lid 20 is formed into a duct structure.

  The Peltier element 14/29 and the temperature reference plate 16/32 for sensitivity correction of the a wavelength band of the rotating base plate 11 and the Peltier element 15/28 and the temperature reference plate 17/31 for sensitivity correction of the b wavelength band optical system. The relative positions are distributed and arranged symmetrically from the rotation axis of the rotation base plate 11 and are arranged at positions that coincide with the optical axis centers 21 and 22 in both wavelength bands.

  The combination of Peltier elements includes a low temperature side Peltier element 14 in the a wavelength band and a high temperature side Peltier element 29 in the b wavelength band, and a high temperature side Peltier element 15 in the a wavelength band and a low temperature side Peltier element 28 in the b wavelength band. Are mounted so that they face each other. On the rotating base plate 11, there is a passage hole 23 through which the infrared energy of the target object is passed to irradiate the a wavelength band and the b wavelength band detecting elements 12 and 13 during normal imaging without performing sensitivity correction. And two symmetrically with respect to the rotation axis for the b wavelength band. With such a configuration, the center of mass of the rotating base plate 11 is point-symmetric and can be completely matched with the center of the rotating shaft.

  The Peltier elements 14, 15, 28, 29 of the rotation mechanism unit 4 and the harness 24 such as the cooling fan 18 are connected to the interface connector 25 of the drive mechanism unit 3 with an appropriate extra length from the hollow portion of the motor shaft 7 and rotated. Even if the harness 24 is twisted when the mechanism unit 4 is operated, the harness 24 is fixed so as not to be disconnected due to stress.

  As shown in the yy sectional view of the figure, the parts of the plunger 26 and the plunger receiver 27 are respectively locked to the fixed part of the drive mechanism unit 3 and the motor shaft 7 of the rotation mechanism unit 4 at appropriate angles, The rotation mechanism unit 4 includes a positioning mechanism that fixes the position of the rotation base plate 11 at a normal shooting position where sensitivity correction is not performed. By doing so, even when the servo is turned off, the rotating base plate 11 can be rotated from the position at the time of normal photographing by the surrounding environment such as vibration, so that the field of view is not obstructed.

  FIG. 2 shows the external appearance of the sensitivity correction mechanism and infrared imaging device of the present invention. In this figure, (a) shows an external perspective view of the infrared imaging device, and (b) and (c) show external perspective views of the sensitivity correction mechanism. The external perspective view of the sensitivity correction mechanism in FIG. 6C is an enlarged perspective view of the external appearance perspective view of the rotation mechanism unit 4 shown in FIG. The figure shows an external perspective view of the sensitivity correction mechanism shown in FIG. In the figure, reference numeral 21 denotes the a wavelength band optical axis center, and 22 denotes the b wavelength band optical axis center.

Next, the operation of the sensitivity correction mechanism of the present invention will be described.
(1) When sensitivity correction is not performed, such as when the power is turned off or during shooting of the target object, the sensitivity correction mechanism passes through two places provided on the rotary base plate 11 as shown in FIG. The rotation base plate 11 is rotated to a position where the center of the hole 23 substantially coincides with the optical axis centers 21 and 22 of the a wavelength band optical system and the b wavelength band optical system, respectively, and the infrared energy of the target object is passed through the through hole 23 as it is. The light is passed through and irradiated on each of the wavelength band detection elements 12 and 13, and an image of the target object is displayed on the monitor 30.

  (2) Next, when the servo is turned on by the “correction start” command signal from the sensitivity correction circuit, the drive current flows to the drive motor 5 and the rotation mechanism unit 4 is connected via the motor shaft 7 directly connected to the drive motor 5. Starts rotating.

  (3) The rotation mechanism unit 4 performs position control based on the rotation angle detected by the potentiometer 6, and is set by position control processing after rotating 90 ° clockwise as shown in FIG. 3B. Hold that position for a time.

  (4) In the state of (3) above, the a wavelength band detecting element 12 is the a wavelength band low temperature side temperature reference plate 16 on the optical system optical axis 21, and the b wavelength band detecting element 13 is the optical system light. The infrared energy of the b wavelength band low temperature side temperature reference plate 31 on the axis 22 is received for a certain period of time, and low temperature side temperature reference data is acquired.

  (5) Next, the rotation mechanism unit 4 rotates 180 ° counterclockwise, and maintains the position for the time set by the position control process in the same manner as (3) above.

  (6) In the state of (5) above, the a wavelength band detecting element 12 is the a wavelength band high temperature side temperature reference plate 17 on the optical system optical axis 21, and the b wavelength band detecting element 13 is the optical system light. The infrared energy of the b wavelength band high temperature side temperature reference plate 32 on the axis 22 is received for a certain period of time, and high temperature side temperature reference data is acquired.

  (7) After obtaining the reference data in (6) above, the rotation mechanism 4 is rotated 90 degrees clockwise to return to the photographing state, and after returning to the state shown in FIG. Turn off.

  The position control is turned off when the rotation mechanism unit 4 is rotated and sensitivity correction is not performed. At this time, as shown in FIG. 4A, the plunger bearing 27 provided on the motor shaft 7 is turned off. Due to the engagement between the concave portion and the plunger 26 provided in the drive mechanism unit 3, the rotation mechanism unit 4 is mechanically fixedly positioned in the rotation direction, and the center of mass of the mass is the center of rotation even when external disturbance such as vibration is received. And the ball 34 is constantly pressurized at a constant pressure by pressing the spring 33 provided inside the plunger 26, the rotational position is locked by the concave portion of the plunger bearing 27, and the motor torque, etc. As long as a rotational torque not less than a predetermined value is generated, the rotation mechanism unit 4 does not rotate.

  FIG. 4B shows a state where the concave portion of the plunger bearing 27 of the motor shaft 7 is disengaged from the plunger 26 provided in the drive mechanism unit 3 and the rotation mechanism unit 4 is not mechanically positioned (sensitivity correction). State at the time of execution).

It is a figure which shows the sensitivity correction mechanism of this invention. It is a figure which shows the external appearance of the sensitivity correction mechanism and infrared imaging device of this invention. It is operation | movement explanatory drawing of the sensitivity correction mechanism of this invention. It is a figure which shows the positioning locking mechanism of the rotation mechanism part of this invention. It is a figure which shows the structure of an infrared imaging device. It is a figure which shows the sensitivity characteristic of an infrared rays detection element. It is a figure which shows the sensitivity correction mechanism of an infrared imaging device. It is a figure which shows the conventional 2 wavelength optical system sensitivity correction mechanism. It is a figure which shows the conventional sensitivity correction mechanism using a Peltier device. It is a figure which shows the conventional sensitivity correction mechanism using a Peltier device. It is a figure which shows the conventional sensitivity correction mechanism using a Peltier device. It is a figure which shows the conventional sensitivity correction mechanism and cooling structure using a Peltier device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 a wavelength band optical system 2 b wavelength band optical system 3 Drive mechanism part 4 Rotation mechanism part 5 Drive motor 6 Potentiometer 7 Motor shaft 8 Potentiometer shaft 9 1st gear 10 2nd gear 11 Rotation base plate 12 a wavelength band detection Element 13 b wavelength band detection element 14 a wavelength band low temperature side Peltier element 15 a wavelength band high temperature side Peltier element 16 a wavelength band low temperature side temperature reference plate 17 a wavelength band high temperature side temperature reference plate 18 cooling fan 19 heat dissipation pin fin 20 top Lid 21 a wavelength band optical axis center 22 b wavelength band optical axis center 23 passage hole 24 harness 25 interface connector 26 plunger 27 plunger bearing 28 b wavelength band low temperature side Peltier element 29 b wavelength band high temperature side Peltier element 30 monitor 31 b wavelength band Low temperature side temperature reference plate 32 b wavelength band high temperature side temperature reference plate 33 Spring 34 baud 35 a wavelength band infrared detector 36 a wavelength band infrared detector 37 AD conversion circuit 38 bearing

Claims (5)

In an infrared imaging device provided with an infrared detector having a plurality of infrared detection elements corresponding to a plurality of optical systems,
A rotation base plate disposed at a position intersecting the infrared incident optical path to the infrared detector of each optical system, and a drive mechanism unit for rotating the rotation base plate,
The rotating base plate is provided with a plurality of through holes for passing infrared incident light to the infrared detector of each optical system, and a temperature reference plate for correcting the sensitivity of the infrared detecting element,
The drive mechanism rotates the rotating base plate, arranges the passage hole at a position intersecting with an infrared incident optical path of each optical system at the time of capturing an infrared image, and adjusts the temperature at the time of sensitivity correction of the infrared detection element. A sensitivity correction mechanism for an infrared detector, wherein a reference plate is disposed at a position intersecting with an infrared incident optical path of each optical system to block infrared incident light, and the temperature reference plate is opposed to the infrared detector. An infrared imaging device having   The temperature reference plate is disposed on the front and back surfaces of the rotating base plate so as to overlap each other as a pair of high and low temperature reference plates with a Peltier element interposed therebetween, and the pair of high temperature and low temperature The reference plates are arranged at a plurality of locations on the rotating base plate, and the high temperature side and the low temperature side of each pair of temperature reference plates arranged at the plurality of locations are opposite to each other on the front surface and the back surface of the rotating base plate. The infrared imaging device having a sensitivity correction mechanism for an infrared detector according to claim 1, wherein the infrared imaging device is arranged as described above.   3. The infrared detector according to claim 1, wherein a heat radiating pin fin is attached to the rotating base plate, and a cooling fan that blows cool air to the heat radiating pin fin is provided as an integral structure with the rotating base plate. An infrared imaging device having a sensitivity correction mechanism.   The members of the rotation mechanism unit are arranged so that the center of gravity of the rotation mechanism unit including at least the passage hole and the temperature reference plate arranged on the rotation base plate is point-symmetric about the rotation axis of the rotation base plate. An infrared imaging apparatus having a sensitivity correction mechanism for an infrared detector according to any one of claims 1 to 3.   5. A positioning and fixing mechanism comprising an engaging mechanism between a locking groove and a protrusion so that the rotation of the rotating base plate is locked at a predetermined position. An infrared imaging device having the sensitivity correction mechanism of the infrared detector described in 1.

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