JP5493281B2 - Wedge prism structure of infrared imaging device - Google Patents

Description

  The present invention relates to a wedge prism structure of an infrared imaging device that takes an image of an object (object) using two wedge prisms, and in particular, an infrared imaging device capable of directing the visual axis direction in the EL and AZ directions. Related to the wedge prism structure.

  2. Description of the Related Art Conventionally, an infrared imaging apparatus that captures an object to be photographed (target object) using two wedge prisms (optical systems) is known (see, for example, Patent Document 1). In the case of such an infrared imaging device, it is possible to take an image of an object using infrared rays at night as well as in the daytime.

[Conventional wedge prism layout]
Here, an outline of a wedge prism structure of a conventional infrared imaging device will be described with reference to FIGS. Here, FIG. 9 is a perspective view showing the arrangement configuration of the conventional wedge prism, and FIG. 10 is a schematic diagram showing the arrangement configuration of the wedge prism of FIG. FIG. 11 is an explanatory diagram for explaining a search operation by a conventional wedge prism.

  That is, as shown in FIG. 9 and FIG. 10, the wedge prism structure of the infrared imaging device has a circular wedge-shaped wedge prism 2 and a wedge prism 3 that sequentially enter infrared rays from a target in order. The arranged prism unit 4 and an infrared detector 5 that receives infrared rays after entering the wedge prisms 2 and 3 and converts them into electrical signals are provided. As shown in FIG. 10, the wedge prism 3 is arranged in an inverted state with respect to the wedge prism 2.

  In the wedge prism structure configured as described above, the visual axis L can be set to the EL and AZ directions by rotating the two wedge prisms 2 and 3 in a predetermined direction by a rotation driving mechanism (not shown). In this way, the infrared rays are inclined by a predetermined angle by the wedge prism 2 and the wedge prism 3, and as a result, the infrared rays from the target can be incident on the substantially central position of the detector 5 as shown in FIG. 10. it can.

  More specifically, the infrared ray incident as the visual axis L from the target is refracted by a predetermined angle by the wedge prism 2, then incident on the wedge prism 3, and is substantially parallel after passing through the wedge prism 3. It becomes light and is received by the detector 5.

  Next, the search operation by the conventional wedge prism structure will be specifically described with reference to FIG. Here, the arrow in FIG. 11 indicates the apex direction of the wedge prisms 2 and 3, the AZ angle indicates Azimuse, and the EL angle indicates elevation.

That is, (1) when performing a search operation of the AZ angle only, a wedge prism 2 angle theta ₁ is rotated counterclockwise, the angle theta ₁ to rotate the wedge prism 3 also counterclockwise. In addition, when the search operation is performed with the AZ angle in this way, and then (2) the shift to the EL angle search operation is performed, the wedge prism 2 is rotated counterclockwise by an angle θ ₂ and the wedge prism 3 is moved. Similarly, an operation of rotating the angle θ ₂ +90 degrees counterclockwise is performed.

  As described above, by performing (1) AZ angle search operation and (2) EL angle search operation, the infrared light incident as the visual axis from the target is refracted at a predetermined angle by the wedge prism 2. Then, the light is incident on the wedge prism 3, and after passing through the wedge prism 3, it becomes almost parallel light and can be received by the detector 5 (FIG. 10).

  Further, as a conventional technique related to this type of infrared imaging apparatus, Patent Document 1 discloses a visual axis directing for visual axis directing for searching and tracking a flying object by manipulating the rotation angles of two wedge prisms. An infrared imaging device having a mechanism is disclosed.

JP 2006-329744 A

However, the conventional wedge prism structure described above has the following problems. That is, as shown in FIG. 11, the state where the search operation is performed only on the AZ angle by the rotation of the wedge prism 2 and the wedge prism 3 around EL = AZ = 0 degree is shifted to the search operation of the EL angle instantaneously. When trying to do so, the wedge prism 3 must be instantaneously rotated by 90 degrees or more (θ ₂ +90 degrees), resulting in a problem that the angular acceleration becomes infinite. That is, when the visual axis directing control is performed in the vicinity of the azimuth parallel to the prism rotation axis P in this way, the rotational angular acceleration of the wedge prism becomes very large, which causes a problem in drive characteristics.

  Specifically, it is impossible to avoid the occurrence of a region where the angular acceleration of the wedge prism is infinite or extremely large in the vicinity of EL = AZ = 0 degrees (hereinafter, this region is referred to as “singular region”). The problem is occurring.

  The first wedge prism and the second wedge prism constituting the infrared imaging device have a predetermined angle (offset angle) with respect to the rotation axis of the first and second wedge prisms with respect to the visual field center line of the infrared detector. Between the second wedge prism and the infrared detector so that the rotation axis of the wedge prism is parallel to the visual field center line of the infrared detector. It is a requirement that a third wedge prism (fixing wedge prism) is arranged.

  The first wedge prism and the second wedge prism constituting the infrared imaging device have a predetermined angle (offset angle) with respect to the rotation axis of the first and second wedge prisms with respect to the visual field center line of the infrared detector. Between the second wedge prism and the infrared detector so that the rotation axis of the wedge prism is parallel to the visual field center line of the infrared detector. Since the third wedge prism is arranged, there is an effect that it is possible to avoid the singular region, solve the problem of driving the wedge prism, and realize the visual axis orientation satisfying the required characteristics.

  Embodiments of a wedge prism structure of an infrared imaging device according to the present invention will be described below in detail with reference to the accompanying drawings. In the following examples, the outline and features of the wedge prism structure of the infrared imaging device according to Example 1 will be described in order, and finally the effects of Example 1 will be described.

[Outline and features of wedge prism structure]
First, the outline and features of the wedge prism structure according to the first embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a perspective view illustrating an arrangement configuration of wedge prisms according to the first embodiment. FIG. 2 is a schematic diagram illustrating an arrangement configuration of wedge prisms according to the first embodiment. FIG. 3 is an explanatory diagram for explaining the traveling path of infrared rays by the wedge prism.

  Here, the wedge prism structure of the infrared imaging apparatus according to the first embodiment includes a wedge prism 20 (first wedge prism) and a wedge prism 30 (second wedge) arranged so as to be inverted with respect to the wedge prism 20. The wedge prisms 20 and 30 are respectively inclined with respect to the center line of the field of view of the detector 50 by a predetermined angle (offset angle). The fixed wedge prism for fixing is arranged between the wedge prism 30 and the detector 50 so that the prism rotation axis P of the wedge prism is parallel to the center line of the visual field of the detector 50. 45 (third wedge prism) is characteristic.

  Specifically, the prism rotation axis P of the wedge prisms 20 and 30 and the visual field center line M of the detector 50 are arranged so as to have a predetermined offset angle, and the fixed wedge prism 45 is provided, thereby providing a visual axis orientation. In this drive configuration, it is possible to avoid a sudden increase in rotational angular acceleration due to the wedge prisms 20 and 30 in the vicinity of “EL = AZ = 0 degree” (singular point).

  That is, as shown in FIG. 1, the wedge prism structure has a circular shape as a whole, and a prism unit 40 in which wedge prisms 20 and wedge prisms 30 each having a wedge shape (triangular shape) are arranged inside. And a fixed wedge prism 45 and a detector 50 in which infrared detection elements for converting incident light into electric signals are arranged in an array.

  As shown in FIG. 2, the electric circuit includes a rotation drive mechanism 61 for rotating the wedge prisms 20 and 30 to a predetermined angle, an angle detection unit 63 for detecting the rotation angle of the wedge prisms 20 and 30, and A rotation drive mechanism control unit 62 that supplies electric power for driving the rotation drive mechanism 61 and an arithmetic processing unit 64 are configured.

  The arithmetic processing unit 64 generates an angle control signal based on the angles of the wedge prisms 20 and 30 detected by the angle detection unit 63 and a predetermined infrared image based on the infrared light received by the detector 50. The process which produces | generates is performed.

  In the wedge prism structure configured as described above, the two wedge prisms 20 and 30 are rotated in a predetermined direction (AZ direction and EL direction) by the rotation drive mechanism 61, whereby the visual axis L is set to be EL and AZ oriented. In this way, infrared rays are inclined at a predetermined angle by the wedge prism 20 and the wedge prism 30. According to this, as shown in FIG. Can be made incident.

  That is, the visual axis direction “EL = AZ = 0 degree” is “EL ≠ 0 degree” in the prism unit 40, and thus the infrared light emitted from the prism unit 40 and incident on the detector 50 is fixed wedge prism 45. Thus, the light is refracted so as to be parallel to the visual field center line M of the detector 50, and the detector 50 can be recognized as infrared light from EL = AZ = 0 degrees. That is, this makes it possible to avoid using the singular region of the prism unit 40.

  Specifically, the infrared rays from the target are refracted by the wedge prism 20 and the wedge prism 30, adjusted by the fixing wedge prism 45, and the infrared light whose wavelength band is narrowed is condensed on the detector 50. it can.

[Results of experiment by the inventor]
Here, the inventor experimentally calculated the operating angle of the wedge prisms 20 and 30 when the predetermined offset angle is 5 ° (search angle 5 °) using an approximate expression. That is, as shown in FIG. 4, in the first embodiment, in the case of searching only for the AZ angle, the starting point is about −60 degrees in the apex direction of the wedge prism 20 and about −100 degrees in the apex direction of the wedge prism 30. As shown, when the wedge prisms 20 and 30 are rotated in a predetermined direction (counterclockwise), infrared rays can be accurately incident on the detector 50.

  In the case of EL search only, when the apex angle direction of the wedge prism 20 is rotated from about −80 degrees and the apex angle direction of the wedge prism 30 is rotated from about −105 degrees, the infrared ray is accurately transmitted to the detector 50 again. It was found that it can be made incident on.

As described above, in the case of the first embodiment, when switching from the search state of only the AZ angle to the EL angle search operation, it is necessary to rotate the wedge prism 30 by 90 ° (θ ₂ +90 degrees) or more as in the prior art. As shown in FIG. 4, the AZ search by the AZ angle and the EL search by the EL angle are performed, thereby avoiding the singular region, reducing the load caused by the driving of the wedge prism, and the infrared ray with respect to the detector 50. Can be accurately incident.

  As described above, according to the wedge prism structure according to the first embodiment, the wedge prism 20 and the wedge prism 30 included in the prism unit 40 are arranged in the field center line M of the infrared detector 50. The prism rotation axes P of the wedge prisms 20 and 30 are arranged so as to incline at a predetermined offset angle, respectively, and between the wedge prism 30 and the detector 50, the visual field center line M of the detector 50 Thus, since the fixing wedge prism 45 is arranged so that the prism rotation axes P of the wedge prisms 20 and 30 are parallel to each other, the singular region is avoided and the problem of driving the wedge prism is solved. In addition, it is possible to achieve visual axis orientation that satisfies the required characteristics.

  Next, the wedge prism structure of the infrared imaging device according to the second embodiment will be described with reference to FIGS. 5 and 6. Here, FIG. 5 is a schematic diagram showing the arrangement of the wedge prism according to the second embodiment, and FIG. 6 is an explanatory diagram for explaining the infrared traveling path by the wedge prism. Since the circuit configuration shown in the second embodiment is the same as that of the first embodiment, detailed description thereof is omitted.

  That is, as shown in FIG. 5, in the first embodiment described above, the wedge prisms 20 and 30 are inclined at a predetermined offset angle, and the fixed wedge prism 45 is disposed between the wedge prism 30 and the detector 50. However, in the second embodiment, the two wedge prisms 21 and 22 constituting the prism unit 40 are arranged so as to be substantially perpendicular to the mounting reference plane, and the wedge of the two wedge prisms 21 and 22 is disposed. On the front side of the prism 21 (left side in FIG. 5) is incident light from the target, which is incident on infrared rays parallel to the visual axis L (field center line M) of the detector 50 and to the wedge prism 21. In addition, a fixed wedge prism 46 that inclines (bends) the optical path of infrared rays so as to have a predetermined offset angle is disposed. There is a feature.

  Specifically, as shown in FIG. 6, when the infrared rays from the target are incident on the wedge prism 21 by the fixed wedge prism 46, a predetermined offset angle with respect to the visual field center line M of the detector 50. The infrared rays are inclined by a certain amount, and the infrared rays are parallel to the detector 50 through the wedge prism 21 and the wedge prism 22 and received by the detector 50. That is, in this case, even in the case of the wedge prism structure of the second embodiment, the singular region can be avoided even when the visual axis L is EL = AZ = 0 degrees as in the first embodiment.

  As described above, according to the wedge prism structure of the infrared imaging device according to the second embodiment, the front side of the wedge prism 21 of the two wedge prisms 21 and 22 is incident light from the target. A fixed wedge that injects infrared rays parallel to the visual axis (field center line M) of the detector 50 and tilts the optical path of the infrared rays so that the wedge prism 21 has a predetermined angle (offset angle). Since the prism 46 is provided, the infrared light incident on the wedge prism 21 is inclined at a predetermined offset angle. Therefore, as in the first embodiment, a singular region is avoided and the wedge prism is driven. It is possible to solve the problem and realize the visual axis orientation satisfying the required characteristics.

  Next, the wedge prism structure of the infrared imaging device according to the third embodiment will be described with reference to FIGS. Here, FIG. 7 is a schematic diagram showing the arrangement configuration of the wedge prism according to the third embodiment, and FIG. 8 is an explanatory diagram for explaining the traveling path of infrared rays by the wedge prism. Since the circuit configuration of the third embodiment is the same as that of the first and second embodiments, detailed description thereof is omitted.

  That is, as shown in the figure, in Example 3, the prism unit 42 constituting the wedge prism structure is arranged inside the prism unit 42 with respect to the visual field center line M of the infrared detector 50. A feature is that the prism rotation axes P of the wedge prisms 23 and 24 are arranged so as to be inclined at a predetermined angle (offset angle).

  That is, by forming a predetermined offset angle in the incident on the prism unit 42, the singular region can be avoided even when the visual axis is “EL = AZ = 0” degrees. Specifically, as shown in FIG. 8, the prism unit 42 and the entire detector 50 are fixed in an inclined state with respect to the attachment reference plane, and a predetermined offset angle is generated, so that the visual axis L becomes “ Even in the case of “EL = AZ = 0 degree”, the singular region can be avoided.

  As described above, according to the wedge prism structure of the infrared imaging apparatus according to the third embodiment, the prism unit 42 constituting the infrared imaging apparatus is in the prism unit 42 with respect to the visual field center line M of the detector 50. Are arranged such that the prism rotation axes P of the wedge prisms 23 and 24 arranged inside each of them are inclined at a predetermined angle (offset angle), and the arrangement angle of the detector 50 is the same as the inclination of the prism unit 42. Since the structure is arranged so as to be inclined at an angle, it is possible to avoid the singular region, solve the problem of driving the wedge prism, and realize the visual axis orientation satisfying the required characteristics.

  The following additional notes are further disclosed with respect to the embodiments including the above-described Examples 1 to 3.

(Appendix 1) A prism unit having a first wedge prism that receives infrared rays from a target, and a second wedge prism arranged so as to be inverted with respect to the first wedge prism, and the first In the wedge prism structure of the infrared imaging device provided with an infrared detector that receives infrared light after being incident on the second wedge prism and converts it into an electrical signal,
The first and second wedge prisms are
The rotation axes of the first and second wedge prisms are arranged so as to be inclined at a predetermined offset angle with respect to the visual field center line of the infrared detector, and the second wedge prism and the infrared detector A third wedge prism is arranged between the first and second wedge prisms so as to be parallel to the rotation axis of the first and second wedge prisms with respect to the visual field center line of the infrared detector. The wedge prism structure of the infrared imaging device.

(Additional remark 2) The 3rd wedge prism arrange | positioned so that it may become in parallel with the rotating shaft of said 1st, 2nd wedge prism is a wedge prism for fixation with which the arrangement angle was fixed. 1. A wedge prism structure for an infrared imaging device according to 1.

(Supplementary note 3) The third wedge prism arranged so as to be parallel to the rotation axis of the first and second wedge prisms is arranged in the same direction as the apex angle of the second wedge prism. 2. A wedge prism structure for an infrared imaging device according to appendix 1.

(Additional remark 4) The prism unit which has the 1st wedge prism which injects the infrared rays from a target object, and the 2nd wedge prism arranged so that it may invert with respect to the said 1st wedge prism, Said 1st In the wedge prism structure of the infrared imaging device provided with an infrared detector that receives infrared light after being incident on the second wedge prism and converts it into an electrical signal,
In the first wedge prism of the first and second wedge prisms, the incident light from the target is incident on the front side of the first wedge prism, and is incident on the infrared rays parallel to the visual axis center line of the infrared detector. A wedge prism structure for an infrared imaging device, wherein a fixing wedge prism is provided to incline the infrared light path so as to have a predetermined offset angle with respect to the first wedge prism.

(Additional remark 5) The 1st wedge prism which injects the infrared rays from a target, The prism unit in which the 2nd wedge prism arranged so that it may be reversed to the 1st wedge prism was arranged inside, In a wedge prism structure of an infrared imaging device including an infrared detector that receives infrared light after being incident on the prism unit and converts the infrared light into an electrical signal,
The prism unit is
With respect to the visual field center line of the infrared detector, the rotation axes of the first and second wedge prisms arranged inside the prism unit are respectively arranged to be inclined at a predetermined offset angle,
The wedge prism structure of an infrared imaging device, wherein the infrared detector is disposed so as to have the same inclination angle as the inclination angle of the prism unit.

(Appendix 6) A first wedge prism that receives infrared rays from a target, and a prism unit in which a second wedge prism arranged so as to be inverted with respect to the first wedge prism is arranged inside, In a wedge prism structure of an infrared imaging device including an infrared detector that receives infrared light after being incident on the prism unit and converts the infrared light into an electrical signal,
The prism unit is
The rotation axes of the first and second wedge prisms arranged inside the prism unit with respect to the visual field center line of the infrared detector are arranged so as to be inclined at a predetermined offset angle, respectively. Between the detector, a fixing wedge prism is disposed,
The wedge prism structure of an infrared imaging device, wherein the detectors are arranged so as to be substantially parallel.

  As described above, the wedge prism structure of the infrared imaging device according to the present invention is useful for a wedge prism structure that uses two wedge prisms provided in the infrared imaging device, and particularly reduces the load of angular acceleration of the wedge prism. It is suitable for the wedge prism structure of an infrared imaging device that can be used.

1 is a perspective view illustrating an arrangement configuration of wedge prisms according to Embodiment 1. FIG. 1 is a schematic diagram illustrating an arrangement configuration of wedge prisms according to Embodiment 1. FIG. It is explanatory drawing explaining the advancing path | route of the infrared rays by a wedge prism. It is explanatory drawing explaining the search operation | movement by a wedge prism. FIG. 6 is a schematic diagram illustrating an arrangement configuration of wedge prisms according to a second embodiment. FIG. 10 is an explanatory diagram illustrating an infrared traveling path by a wedge prism according to a second embodiment. FIG. 6 is a schematic diagram illustrating an arrangement configuration of wedge prisms according to a third embodiment. FIG. 10 is an explanatory diagram illustrating an infrared traveling path by a wedge prism according to a third embodiment. It is a perspective view which shows the arrangement configuration of the conventional wedge prism. It is the schematic which shows the arrangement configuration of the conventional wedge prism. It is explanatory drawing explaining the search operation by the conventional wedge prism.

Explanation of symbols

2, 3, 20, 21, 22, 23, 24, 30 Wedge prism 4, 40, 41, 42 Prism unit 5, 50 Infrared detector 45, 46 Fixed wedge prism 61 Rotation drive mechanism 62 Rotation drive mechanism control section 63 Angle Detection unit 64 arithmetic processing unit

Claims (4)

A prism unit having a first wedge prism for receiving infrared rays from a target and a second wedge prism arranged so as to be inverted with respect to the first wedge prism; and the first and second wedges In a wedge prism structure of an infrared imaging device including an infrared detector that receives infrared light after being incident on the prism and converts it into an electrical signal,
The first and second wedge prisms are
The rotation axes of the first and second wedge prisms are arranged so as to be inclined at a predetermined offset angle with respect to the visual field center line of the infrared detector, and the second wedge prism and the infrared detector A wedge prism structure for an infrared imaging device, wherein a third wedge prism is disposed between the two and a rotation axis that is parallel to the visual field center line of the infrared detector. The third wedge prism arranged so as to have a rotation axis parallel to the rotation axes of the first and second wedge prisms is a fixed wedge prism having a fixed arrangement angle. Item 12. A wedge prism structure for an infrared imaging device according to Item 1. A prism unit having a first wedge prism for receiving infrared rays from a target and a second wedge prism arranged so as to be inverted with respect to the first wedge prism; and the first and second wedges In a wedge prism structure of an infrared imaging device including an infrared detector that receives infrared light after being incident on the prism and converts it into an electrical signal,
The incident light from the target is incident on the front side of the first wedge prism of the first and second wedge prisms, and infrared rays parallel to the visual field center line of the infrared detector are incident thereon, An infrared ray characterized in that the first wedge prism is provided with a fixed wedge prism that inclines the infrared light path so as to have a predetermined offset angle with respect to a visual field center line of the infrared detector. The wedge prism structure of the imaging device. A first wedge prism that receives infrared rays from a target, a prism unit in which a second wedge prism arranged so as to be inverted with respect to the first wedge prism, and a prism unit in which the second wedge prism is arranged; In a wedge prism structure of an infrared imaging device including an infrared detector that receives infrared rays after being incident and converts them into electrical signals,
The prism unit is
First, second rotary shaft of the wedge prisms, the prism unit and arranged to be inclined to the infrared detector relative to the mounting reference surface of the infrared detector is arranged which is arranged in the interior of the prism unit wedge prism structure of an infrared imaging apparatus characterized by being arranged such that said coincident with field center line of the infrared detector in the case of.

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