HYPERSPECTRAL CAMERA LENS UNIT AND HYPERSPECTRAL CAMERA

Abstract

A lens section includes a housing and an optical system disposed within the housing. The optical system includes a Fabry-Perot interference filter, a first aperture formed integrally with the Fabry-Perot interference filter and through which light traveling toward the Fabry-Perot interference filter or light passing through the Fabry-Perot interference filter passes, a first lens section that focuses or collimates light traveling from an incident section toward the Fabry-Perot interference filter, and a second lens section that images light passing through the Fabry-Perot interference filter and emitted from an emission section. Viewed in the optical axis direction, a width of the light at an incident position at the first aperture is greater than a width of the first aperture.

Description

Technical area

[0001] The present disclosure relates to a hyperspectral camera lens unit and a hyperspectral camera. State of the art

[0002] There is a hyperspectral camera that spectrally separates light into wavelengths using a Fabry-Perot interference filter and captures the spectrally separated light as an image. As a related technology, for example, JP 2016-11986 A discloses an image pickup lens section including an objective lens, an imaging lens, and a Fabry-Perot interference filter disposed therebetween. The light guided by the image pickup lens section is captured (image-captured) by an image pickup unit provided in a camera body. Summary of the inventionTechnical problem

[0003] One aspect of the present disclosure is to provide a hyperspectral camera lens unit that enables a hyperspectral camera to satisfactorily capture an image, and a hyperspectral camera capable of satisfactorily capturing an image. Solution to the problem

[0004] A hyperspectral camera lens unit according to one aspect of the present disclosure is [1] “a hyperspectral camera lens unit including a housing having an incident portion onto which light is incident, an emitting portion from which the light is emitted, and a mounting portion to which an optical device is detachably mounted / fixed; and an optical system disposed within the housing.The optical system includes a Fabry-Perot interference filter comprising a pair of mirror sections with a variable pitch therebetween, which transmits light from the incident section according to the pitch between the pair of mirror sections; a first aperture formed integrally with the Fabry-Perot interference filter, through which light traveling toward the Fabry-Perot interference filter or light passing through the Fabry-Perot interference filter passes; a first lens section that focuses or collimates / collects light traveling from the incident section toward the Fabry-Perot interference filter; and a second lens section that images the light passing through the Fabry-Perot interference filter and emitted from the emission section. Viewed in the optical axis direction, a width of the light at an incident position at the first aperture is larger than a width of the first aperture.

[0005] In the hyperspectral camera lens unit, the width of the light at the incident position at the first aperture, viewed in the optical axis direction of the light, is larger than the width of the first aperture. Accordingly, compared with, for example, the case where the light narrowed by a lens to a width narrower than the width of the first aperture passes through the first aperture, the width of the first aperture can be maximized and the amount of light can be ensured. Furthermore, the light traveling toward the Fabry-Perot interference filter or the light passing through the Fabry-Perot interference filter can be narrowed by the first aperture, and the depth of field can be increased. Furthermore, the first aperture is integrally formed with the Fabry-Perot interference filter.Accordingly, compared to, for example, a separate formation of the first aperture with respect to the Fabry-Perot interference filter, the occurrence of design deviations (e.g., a deviation in the distance or angle between the pair of mirror sections and the first aperture, misalignment in a direction perpendicular to an optical axis, or the like) can be suppressed. As described above, the hyperspectral camera lens unit enables a hyperspectral camera to capture an image satisfactorily.

[0006] A hyperspectral camera lens unit according to one aspect of the present disclosure may be [2] "the hyperspectral camera lens unit described in [1], in which the Fabry-Perot interference filter is arranged at a position where a principal ray passing through an outer edge of an imaging range of the light shaped by the second lens intersects an optical axis of the light." In this case, the size of the imaging range of the light shaped by the second lens can be kept constant regardless of the size of the first aperture. In addition, since the angle of incidence of the light on the Fabry-Perot interference filter becomes constant, the wavelength shift in the Fabry-Perot interference filter can be easily corrected.

[0007] A hyperspectral camera lens unit according to one aspect of the present disclosure may be [3] "the hyperspectral camera lens unit described in [1] or [2], in which the first aperture is arranged on an incident portion side with respect to the pair of mirror portions." In this case, stray light or light with a large angle of incidence can be cut off by the first aperture before being incident on the pair of mirror portions, and noise can be reduced.

[0008] A hyperspectral camera lens unit according to one aspect of the present disclosure may be [4] "the hyperspectral camera lens unit described in [1] to [3], wherein the optical system further comprises a second aperture arranged between the Fabry-Perot interference filter and the first lens portion or between the Fabry-Perot interference filter and the second lens portion." In this case, the light can be narrowed to a desired angular range by the first aperture and the second aperture, and the resolution in capturing an image for each wavelength can be improved.

[0009] A hyperspectral camera lens unit according to one aspect of the present disclosure may be [5] “the hyperspectral camera lens unit described in [4], in which the second aperture is formed as an opening formed in a substrate, and in which the Fabry-Perot interference filter is attached / fixed to the substrate.” In this case, the Fabry-Perot interference filter (first aperture) may be appropriately fixed near the second aperture.

[0010] A hyperspectral camera lens unit according to one aspect of the present disclosure may be [6] "the hyperspectral camera lens unit described in [5], further comprising a first lens holder holding the first lens portion and a second lens holder holding the second lens portion. The carrier is sandwiched and fixed between the first lens holder and the second lens holder." In this case, the carrier can be appropriately fixed.

[0011] A hyperspectral camera lens unit according to one aspect of the present disclosure may be [7] "the hyperspectral camera lens unit described in any one of aspects [1] to [6], wherein, when viewed in the optical axis direction, an area of ​​a light incident region at the incident position at the first aperture is equal to or smaller than 110% of an area of ​​the first aperture." In this case, light utilization efficiency can be improved.

[0012] A hyperspectral camera lens unit according to one aspect of the present disclosure may be [8] “the hyperspectral camera lens unit described in any one of aspects [1] to [7], wherein the optical system further comprises an additional optical system arranged between the Fabry-Perot interference filter and the first lens portion, which reduces the width of the light.” In this case, the light utilization efficiency can be improved.

[0013] A hyperspectral camera lens unit according to one aspect of the present disclosure may be [9] "the hyperspectral camera lens unit described in any one of aspects [1] to [7], wherein the optical system further comprises an additional optical system disposed between the Fabry-Perot interference filter and the first lens portion and collimating the light." In this case, the occurrence of a wavelength shift can be suppressed by collimating the light before it hits the Fabry-Perot interference filter.

[0014] A hyperspectral camera lens unit according to one aspect of the present disclosure may be

[10] “the hyperspectral camera lens unit described in [9], in which the additional optical system reduces the width of the light.” In this case, the light utilization efficiency can be improved.

[0015] A hyperspectral camera lens unit according to one aspect of the present disclosure may be

[11] "the hyperspectral camera lens unit described in [1] to

[10] , wherein the Fabry-Perot interference filter comprises a substrate having a first surface and a second surface opposite to the first surface, and has a first laminated structure disposed on the first surface. The first laminated structure includes a first laminate disposed on the first surface and including one of the pair of mirror portions, and a second laminate disposed on a side opposite to the substrate with respect to the first laminate and including the other of the pair of mirror portions." Also in this case, an image can be satisfactorily captured by the hyperspectral camera.

[0016] A hyperspectral camera lens unit according to one aspect of the present disclosure may be

[12] "the hyperspectral camera lens unit described in

[11] , wherein the Fabry-Perot interference filter further comprises a second laminated structure disposed on the second surface of the substrate. A recess is formed on a surface of the second laminated structure opposite to the substrate. At least a part of the recess overlaps the first aperture when viewed in the optical axis direction." In this case, since the recess is formed, the light can easily pass through a portion of the Fabry-Perot interference filter that overlaps the first aperture, and the light utilization efficiency can be improved.

[0017] A hyperspectral camera lens unit according to one aspect of the present disclosure may be

[13] “the hyperspectral camera lens unit described in any one of aspects [1] to

[10] , wherein the Fabry-Perot interference filter includes a first substrate having a first surface, a second substrate having a second surface opposite to the first surface, one of the pair of mirror portions formed on the first surface, and the other of the pair of mirror portions formed on the second surface.” Also in this case, an image can be satisfactorily captured by the hyperspectral camera.

[0018] A hyperspectral camera lens unit according to one aspect of the present disclosure may be

[14] "the hyperspectral camera lens unit described in any one of aspects [1] to

[13] , wherein the first aperture is formed by providing a light-shielding layer in a region of the Fabry-Perot interference filter other than the light-transmitting region, while the light-shielding layer is not provided in the light-transmitting region." In this case, the first aperture may be formed integrally with the Fabry-Perot interference filter.

[0019] A hyperspectral camera according to one aspect of the present disclosure is

[15] "the hyperspectral camera lens unit described in any one of aspects [1] to

[14] ; and a camera unit that is the optical device attached to the attachment portion of the housing, the camera unit including an image pickup element that (image-captures) the light emitted from the emission portion." For the reasons described above, the hyperspectral camera can satisfactorily capture an image. Advantageous effects of the invention

[0020] According to one aspect of the present disclosure, it is possible to provide the hyperspectral camera lens unit that enables the hyperspectral camera to satisfactorily capture an image, as well as to provide the hyperspectral camera capable of satisfactorily capturing an image. Brief description of the drawings Fig. 1 is a configuration view of a hyperspectral camera according to an embodiment. Fig. 2 is a perspective view of a filter unit. Fig. 3 is a cross-sectional view of the filter unit along the line III-III in Fig. 2. Fig. Figure 4 is a perspective view of a Fabry-Perot interference filter. Fig. Figure 5 is a cross-sectional view of the Fabry-Perot interference filter along the line VV in Fig. 4. Fig. 6 (a) and (b) are views for describing the control of the angle of incidence by a first aperture and a second aperture. Fig. 7 is a configuration view of a first modification example. Fig. 8 is a configuration view of a second modification example. Fig. 9 is a cross-sectional view of a Fabry-Perot interference filter of a third modification example. Fig. 10 (a) and (b) are views for describing further modification examples. Fig. 11 (a) and (b) are views for describing further modification examples. Fig. 12 (a) and (b) are views for describing further modification examples. Fig. 13 is a view for describing another modification example. Description of the embodiments

[0021] An embodiment of the present disclosure will be described in detail below with reference to the drawings. In the following description, the same reference numerals are used for the same or corresponding elements, and duplicate descriptions are omitted.

[0022] As in Fig. As shown in Figure 1, a hyperspectral camera 1 includes a lens unit 2 (hyperspectral camera lens unit) and a camera unit 5 (optical device). The lens unit 2 is an interchangeable lens device that is replaceably (removably) attached to the camera unit 5. The hyperspectral camera 1 is a camera that can spectrally separate light into several tens to several hundred bands according to wavelength and capture an image for each band.

[0023] The lens unit 2 comprises a housing 21 and an optical system 22 arranged within the housing 21. The optical system 22 comprises a Fabry-Perot interference filter 10, a first lens section 23, and a second lens section 24. The Fabry-Perot interference filter 10 is attached / fixed to a carrier 31 and, together with the carrier 31, forms a filter unit 30. The camera unit 5 comprises a housing 51 and an image pickup element 52 arranged within the housing 51. In the hyperspectral camera 1, the light L focused by the first lens section 23 is transmitted along an optical axis direction D through the Fabry-Perot interference filter 10. The light L transmitted through the Fabry-Perot interference filter 10 is imaged by the second lens section 24 and imaged by the image pickup element 52. In the following, the Fabry-Perot interference filter 10 is first described with reference to the Fig. 4 and Fig. 5 described. [Fabry-Perot interference filter]

[0024] As in Fig. As shown in Figure 4, the Fabry-Perot interference filter 10 has a light transmitting region 10a. The Fabry-Perot interference filter 10 is a rectangular plate-shaped member. As described later, the Fabry-Perot interference filter 10 is arranged so that a thickness direction is parallel to the optical axis direction D. The light transmitting region 10a is a columnar region with a center line parallel to the optical axis direction D. When viewed in the optical axis direction D, the center of the light transmitting region 10a coincides with the center of the Fabry-Perot interference filter 10.

[0025] As in Fig. As shown in Figure 5, the Fabry-Perot interference filter 10 includes a substrate 11 whose thickness direction extends in the optical axis direction D. The material of the substrate 11 is, for example, silicon, quartz, glass, or the like. The substrate 11 has a first surface 11a and a second surface 11b opposite the first surface 11a. The first surface 11a and the second surface 11b are, for example, flat surfaces perpendicular to the optical axis direction D. A first laminated structure 12 is laminated to the first surface 11a, and a second laminated structure 13 is laminated to the second surface 11b.

[0026] The first laminated structure 12 comprises an anti-reflection layer 121, a first laminate 122, an intermediate layer 123, and a second laminate 124. The anti-reflection layer 121, the first laminate 122, the intermediate layer 123, and the second laminate 124 are laminated in this order on the first surface 11a of the substrate 11. Namely, the first laminate 122 is arranged over the anti-reflection layer 121 on the first surface 11a, and the second laminate 124 is arranged on a side opposite to the substrate with respect to the first laminate 122 (in Fig. 5, a top side). An air gap S is formed between the first laminate 122 and the second laminate 124 by the frame-shaped intermediate layer 123. When the material of the substrate 11 is silicon, the material of both the anti-reflection layer 121 and the intermediate layer 123 is, for example, silicon oxide or the like. The thickness of the intermediate layer 123 is, for example, an integer multiple of 1 / 2 of a design central wavelength. Note that the thickness of the intermediate layer 123 may be greater than an integer multiple of 1 / 2 of the design central wavelength if necessary.

[0027] A portion of the first laminate 122 corresponding to the light transmission area 10a functions as the mirror portion 14. Namely, the first laminate 122 includes the mirror portion 14. The mirror portion 14 is supported by the substrate 11 via the anti-reflection layer 121. As an example, the first laminate 122 is configured by alternately lamination of a plurality of polysilicon layers and a plurality of silicon nitride layers. The optical thickness of each layer constituting the mirror portion 14 is, for example, an integer multiple of 1 / 4 of the design central wavelength. Note that a silicon oxide layer may be used instead of the silicon nitride layer.

[0028] A portion of the second laminate 124 corresponding to the light transmission area 10a functions as the mirror portion 15. Namely, the second laminate 124 includes the mirror portion 15. The mirror portion 15 is supported by the substrate 11 through the anti-reflection layer 121, the first laminate 122, and the intermediate layer 123, and faces the mirror portion 14 in the optical axis direction D with the air gap S therebetween. As an example, the second laminate 124 is configured by alternately laminating a plurality of polysilicon layers and a plurality of silicon nitride layers. An optical thickness of each layer constituting the mirror portion 15 is, for example, an integer multiple of 1 / 4 of the design central wavelength. Note that a silicon oxide layer may be used instead of the silicon nitride layer.Note that a plurality of through-holes are formed in a portion of the second laminate 124 corresponding to the air gap S, to such an extent that the function of the mirror portion 15 is not significantly impaired. The plurality of through-holes is used when the air gap S is formed by removing a portion of the intermediate layer 123 by etching.

[0029] A first electrode 125 and a second electrode 126 are formed in the mirror portion 14. The first electrode 125 surrounds the light transmission region 10a as viewed in the optical axis direction D. The second electrode 126 overlaps the light transmission region 10a as viewed in the optical axis direction D. The shape of the second electrode 126 as viewed in the optical axis direction D is substantially identical to the shape of the light transmission region 10a as viewed in the optical axis direction D. The first electrode 125 and the second electrode 126 are each formed by doping a portion of a polysilicon layer with an impurity to reduce the resistance of that portion.

[0030] A third electrode 127 is formed in the mirror portion 15. The third electrode 127 faces the first electrode 125 and the second electrode 126 with the air gap S therebetween. The third electrode 127 is formed by doping a portion of a polysilicon layer with an impurity to reduce the resistance of that portion. For example, a distance between the second electrode 126 and the third electrode 127 is substantially equal to a distance between the first electrode 125 and the third electrode 127.

[0031] A pair of terminals 16 are provided on the first laminated structure 12 so as to sandwich the light transmission area 10a between them (see Fig. 4). Each terminal 16 is arranged in a through-hole formed in the second laminate 124 and the intermediate layer 123 to open to the side opposite the substrate 11 and reaches the first laminate 122. Each terminal 16 is electrically connected to the first electrode 125 via a wiring 125a.

[0032] A pair of terminals 17 are provided on the first laminated structure 12 so as to sandwich the light transmission area 10a between them (see Fig. 4). Each terminal 17 is arranged in a through-hole formed in the second laminate 124 and the intermediate layer 123 so as to open toward the side opposite the substrate 11 and reach the intermediate layer 123. Each terminal 17 is electrically connected to the second electrode 126 via a wiring 126a and electrically connected to the third electrode 127 via a wiring 127a. Note that a direction in which the pair of terminals 17 sandwich the light transmission region 10a is a direction perpendicular to a direction in which the pair of terminals 16 sandwich the light transmission region 10a (see Fig. 4).

[0033] A pair of grooves 122a are formed in the first laminate 122. Each groove 122a extends annularly to surround a portion of the wiring 126a, the portion of each terminal 17 extending in the optical axis direction D. Each groove 122a electrically insulates the first electrode 125 from the wiring 126a. A groove 122b is formed in the first laminate layer 122. The groove 122b extends annularly along an inner edge of the first electrode 125. The groove 122b electrically insulates the first electrode 125 from the second electrode 126. A region in each of the grooves 122a and 122b may be filled with an insulating material or form an air gap.

[0034] A pair of grooves 124a are formed in the second laminate 124. Each groove 124a extends annularly to surround each of the terminals 16. Each groove 124a electrically insulates each of the terminals 16 from the third electrode 127.

[0035] An area in each of the grooves 124a may be filled with an insulating material or form an air gap.

[0036] The second laminated structure 13 includes an anti-reflection layer 131, a third laminate 132, an intermediate layer 133, and a fourth laminate 134. The anti-reflection layer 131, the third laminate 132, the intermediate layer 133, and the fourth laminate 134 are laminated in this order on the second surface 11b of the substrate 11. The anti-reflection layer 131 and the intermediate layer 133 have the same configurations as the anti-reflection layer 121 and the intermediate layer 123, respectively. The third laminate 132 and the fourth laminate 134 have laminated structures that are symmetrical to the first laminate 122 and the second laminate 124, respectively, with the substrate 11 as a reference. The anti-reflection layer 131, the third laminate 132, the intermediate layer 133 and the fourth laminate 134 have the function of suppressing warpage of the substrate 11.

[0037] A recess 18 is formed on a surface 13a of the second laminated structure 13 opposite the substrate 11. The recess 18 opens to a side opposite the substrate 11. The recess 18 overlaps the light-transmitting region 10a when viewed in the optical axis direction D. The shape of the recess 18, when viewed in the optical axis direction D, is substantially the same as the shape of the light-transmitting region 10a when viewed in the optical axis direction D and, in this example, is circular. A center line of the recess 18 coincides with a center line of the light-transmitting region 10a. The recess 18 is formed in the third laminate layer 132, the intermediate layer 133, and the fourth laminate layer 134 and extends to the anti-reflection layer 131.

[0038] A light-shielding layer 135 is formed on the surface 13a of the second laminated structure 13. The light-shielding layer 135 is formed, for example, over the entire surface 13a. The material of the light-shielding layer 135 is, for example, aluminum or the like. The light-shielding layer 135 shields the light L. In this example, the light-shielding layer 135 shields the light L by reflecting the light L. On the other hand, the light L passes through a region where the light-shielding layer 135 is not formed (in this example, a region where the recess 18 is formed). Namely, the light-transmitting region 10a corresponds to the region where the light-shielding layer 135 is not formed. In this way, in the Fabry-Perot interference filter 10, a first aperture P1 defining the light-transmitting region 10a is formed by the light-shielding layer 135.Namely, the first aperture P1 is formed by providing the light-shielding layer 135 in a region of the Fabry-Perot interference filter 10 that is not the light-transmitting region 10a as viewed in the optical axis direction D, while not providing the light-shielding layer 135 in the light-transmitting region 10a. Furthermore, the first aperture P1 is integrally formed with the Fabry-Perot interference filter 10. The width of the first aperture P1 is fixed (does not change).

[0039] The first aperture P1 is circular in shape when viewed in the optical axis direction D. The (entire) recess 18 completely overlaps the first aperture P1 when viewed in the optical axis direction D. In this example, the shape of the recess 18 when viewed in the optical axis direction D is essentially identical to the shape of the first aperture P1 when viewed in the optical axis direction D. The center line of the recess 18 coincides with a center line of the first aperture P1.

[0040] A protective layer 136 is formed on the light-shielding layer 135 and an inner surface of the recess 18. The material of the protective layer 136 is, for example, aluminum oxide or the like. Note that the optical influence of the protective layer 136 can be neglected by setting the thickness of the protective layer 136 to 100 nm or less (preferably about 30 nm).

[0041] In the Fabry-Perot interference filter 10 configured as described above, when a potential difference is generated between the first electrode 125 and the third electrode 127 by applying a voltage to the first electrode 125 and the third electrode 127 via the plurality of terminals 16 and 17, an electrostatic force corresponding to the potential difference is generated between the first electrode 125 and the third electrode 127. Due to the generation of an electrostatic force between the first electrode 125 and the third electrode 127, the mirror portion 15 is attracted to the mirror portion 14, and the distance between the mirror portion 14 and the mirror portion 15 is adjusted. At this time, the second electrode 126, which is at the same potential as the third electrode 127, functions as a compensating electrode, and the mirror portion 15 is kept flat in the light transmission region 10a.

[0042] In this way, in the Fabry-Perot interference filter 10, a pair of mirror sections 14 and 15, which are opposite to each other in the optical axis direction D, function as a pair of mirror sections whose distance is variable. The wavelength of the light passing through the Fabry-Perot interference filter 10 depends on the distance between the mirror section 14 and the mirror section 15. Therefore, the wavelength of the light passing through the Fabry-Perot interference filter 10 can be selected / adjusted by adjusting the voltage applied to the first electrode 125 and the third electrode 127 (the potential difference generated between the first electrode 125 and the third electrode 127). In this way, the Fabry-Perot interference filter 10 transmits light whose wavelength corresponds to the distance between the mirror sections 14 and 15 from the incident light. [Filter unit]

[0043] As in the Fig. 1 to 3, the filter unit 30 comprises the support 31 (diaphragm plate), the above-described Fabry-Perot interference filter 10, and a bandpass filter 32. As will be described later, the filter unit 30 is arranged such that the thickness direction of the Fabry-Perot interference filter 10 is parallel to the optical axis direction D. In Fig. 2, the Fabry-Perot interference filter 10 is represented by dashed lines and the bandpass filter 32 is represented by two-aspect dashed lines.

[0044] The support 31 is formed, for example, in a substantially circular plate shape from a metal material such as stainless steel. The support 31 has a first surface 31a and a second surface 32b opposite the first surface 31a. The first surface 31a and the second surface 31b are, for example, flat surfaces perpendicular to the optical axis direction D. A recess 33 for arranging the Fabry-Perot interference filter 10 and the bandpass filter 32 is formed in the support 31. The recess 33 is formed on the first surface 31a and opens toward the first surface 31a.

[0045] The recess 33 includes a first recess 34 and a second recess 35. A bottom surface 34a of the first recess 34 and a bottom surface 35a of the second recess 35 lie on the same plane perpendicular to the optical axis direction D. The first recess 34 and the second recess 35 are arranged in an X direction (a direction perpendicular to the optical axis direction D).

[0046] Viewed in the optical axis direction D, both the first recess 34 and the second recess 35 are formed in a rectangular shape. In this example, viewed in the optical axis direction D, both the first recess 34 and the second recess 35 are formed in an elongated shape with the X direction as the longitudinal direction. Viewed in the optical axis direction D, the first recess 34 does not extend to an outer edge of the carrier 31, while the second recess 35 extends to the outer edge of the carrier 31. That is, the second recess 35 opens onto a side surface of the carrier 31.

[0047] A width of the second recess 35 in a Y direction (a direction perpendicular to both the optical axis direction D and the X direction) is larger than a width of the first recess 34 in the Y direction. An opening 36 and a through-hole 37 are formed in the substrate 31. The opening 36 and the through-hole 37 open to the bottom surface 34a of the first recess 34 and the second surface 31b of the substrate 31, respectively. The opening 36 and the through-hole 37 are arranged in the X direction. Viewed in the optical axis direction D, both the opening 36 and the through-hole 37 are circular, for example. The opening 36 forms a second aperture P2 through which the light L traveling toward the Fabry-Perot interference filter 10 passes. In this example, the diameter (width) of the second aperture P2 is larger than the diameter (width) of the first aperture P1.The width of the second aperture P2 is fixed (does not change). The through-hole 37 serves, for example, to allow gas generated from an adhesive material used to attach the Fabry-Perot interference filter 10 and the bandpass filter 32 to escape during the manufacture of the filter unit 30.

[0048] A widened portion 38 is formed in the substrate 31. The widened portion 38 is widened to a side opposite the second recess 35 in the X direction and to both sides in the Y direction with respect to an opening of the first recess 34. The widened portion 38 is a recess formed in the substrate 31 so as to open to the first surface 31a and reach the opening of the first recess 34 with the optical axis direction D as the depth direction. In the present embodiment, a width of the widened portion 38 in the Y direction is equal to the width of the second recess 35 in the Y direction.

[0049] The support 31 includes a partition portion 39. The partition portion 39 is disposed between the first recess 34 and the second recess 35. In the present embodiment, the partition portion 39 is a wall portion extending in the Y direction between the bottom surface 34a of the first recess 34 and the bottom surface 35a of the second recess 35. When a plane in which the bottom surface 34a and the bottom surface 35a lie is taken as a reference plane, a height of the partition portion 39 in the optical axis direction D is less than a height of the first surface 31a of the support 31 in the optical axis direction D and less than a height of a bottom surface 38a of the expanded portion 38 in the optical axis direction D.

[0050] The Fabry-Perot interference filter 10 is arranged on the substrate 31 so that it overlaps the second aperture P2 (opening 36) in the optical axis direction D and the thickness direction is parallel to the optical axis direction D. More specifically, the Fabry-Perot interference filter 10 is arranged within the first recess 34 so that it overlaps the opening 36 in the optical axis direction D and the thickness direction is parallel to the optical axis direction D. The Fabry-Perot interference filter 10 is in contact with the separation portion 39 within the first recess 34. When the bottom surface 34a of the first recess 34 is taken as a reference point, a height of the Fabry-Perot interference filter 10 in the optical axis direction D is lower than the height of the first surface 31a of the support 31 in the optical axis direction D and lower than the height of the bottom surface 38a of the expanded portion 38 in the optical axis direction D.When the bottom surface 34a of the first recess 34 is taken as a reference point, the height of the separation portion 39 in the optical axis direction D is equal to or smaller than the height of the Fabry-Perot interference filter 10 in the optical axis direction D.

[0051] As described above, the Fabry-Perot interference filter 10 is a rectangular plate-shaped member whose thickness direction is the optical axis direction D. The Fabry-Perot interference filter 10 is arranged on the bottom surface 34a of the first recess 34 such that, when viewed in the optical axis direction D, each side of an outer edge of the rectangular shape is parallel to the X direction or the Y direction, and the first aperture P1 faces the second aperture P2 (opening 36). The Fabry-Perot interference filter 10 is fixed to the bottom surface 34a with, for example, an adhesive material. The center line of the first aperture P1 coincides with a center line of the second aperture P2.

[0052] The bandpass filter 32 is arranged on the substrate 31 so as to cover the opening of the first recess 34 and a thickness direction parallel to the optical axis direction D. More specifically, the bandpass filter 32 is arranged within the expanded portion 38 so as to cover the opening of the first recess 34 and the thickness direction parallel to the optical axis direction D. The bandpass filter 32 is fixed to the bottom surface 38a of the expanded portion 38 with, for example, an adhesive material. In the present embodiment, the bandpass filter 32 covers the opening of the first recess 34 and covers part of an opening of the second recess 35. Taking the bottom surface 38a of the expanded portion 38 as a reference point, a height of the bandpass filter 32 in the optical axis direction D is lower than the height of the first surface 31a of the substrate 31 in the optical axis direction D.

[0053] The bandpass filter 32 is formed in the shape of a rectangular plate having the optical axis direction D as the thickness direction and the X direction as the longitudinal direction. The bandpass filter 32 is arranged on the bottom surface 38a of the expanded portion 38 such that each side of an outer edge of the rectangular shape is parallel to the X direction or the Y direction when viewed in the optical axis direction D. The bandpass filter 32 transmits light in a predetermined wavelength range. In addition, although not shown in the figures, a wiring board or the like, for example, electrically connected to the Fabry-Perot interference filter 10 is arranged in the second recess 35. [Lens unit and camera unit]

[0054] As in Fig. 1, the lens unit 2 comprises the housing 21 and the optical system 22 arranged within the housing 21. The optical system 22 includes the above-described Fabry-Perot interference filter 10, the first lens section 23 and the second lens section 24. Furthermore, the optical system 22 includes the above-described first aperture P1 and the second aperture P2.

[0055] The housing 21 is, for example, substantially cylindrical. The housing 21 includes an incident portion 21a onto which the light L is incident, an emitting portion 21b from which the light L is emitted, and a mounting portion 21c to which the camera unit 5 is detachably attached. In this example, the incident portion 21a is formed by an end portion on one side of the housing 21 in the optical axis direction D, and the emitting portion 21b is formed by an end portion on the other side of the housing 21 in the optical axis direction D. In the lens unit 2, the light L incident from the incident portion 21a is guided by the optical system 22 along the optical axis direction D and emitted from the emitting portion 21b toward the camera unit 5.

[0056] The attachment portion 21c is provided at the end portion on one side of the emission portion 21b of the housing 21 (the end portion on the other side in the optical axis direction D). The attachment portion 21c detachably engages with a later-described attachment portion 51b of the camera unit 5. For example, when the lens unit 2 and the camera unit 5 are detachably connected by screwing, the attachment portion 21c is provided with a screw thread or a screw receptacle, and the attachment portion 51b is provided with the other of the screw thread and the screw receptacle, which can be screwed into one of the screw thread and the screw receptacle.

[0057] In this example, the housing 21 is divided / divided in the optical axis direction D and includes a first portion 211 arranged on one side in the optical axis direction D, and a second portion 212 arranged on the other side in the optical axis direction D. The first portion 211 forms a first lens holder that holds the first lens portion 23, and the second portion 212 forms a second lens holder that holds the second lens portion 24. In the present embodiment, the carrier 31 of the filter unit 30 is sandwiched and fixed between the first portion 211 and the second portion 212. For example, the first portion 211 is in contact with the first surface 31a of the carrier 31, and the second portion 212 is in contact with the second surface 31b of the carrier 31.

[0058] Accordingly, the Fabry-Perot interference filter 10 is mounted on an optical axis A between the first lens section 23 and the second lens section 24. The filter unit 30 is fixed on the optical axis A such that the center line of the light transmission area 10a of the Fabry-Perot interference filter 10, the center line of the first aperture P1, and the center line of the second aperture P2 lie on the optical axis A (see Fig. 1 to 5). In this fixed state, the second surface 31b of the support 31 faces the incident section 21a side, and the first aperture P1 is located on the incident section 21a side with respect to the mirror sections 14 and 15 of the Fabry-Perot interference filter 10. The second aperture P2 is located between the first lens section 23 and the Fabry-Perot interference filter 10. Namely, the second aperture P2 is located on the incident section 21a side with respect to the first aperture P1.

[0059] The first lens portion 23 is a focusing optical system that focuses the light L traveling from the incident portion 21a toward the Fabry-Perot interference filter 10. The first lens portion 23 includes at least one lens, and in this example, includes three lenses 23a, 23b, and 23c (lens group) arranged along the optical axis direction D (a direction parallel to the optical axis A). The first lens portion 23 is attached and fixed to the first portion 211 of the housing 21 at an outer peripheral portion of the first lens portion 23. Note that the first lens portion 23 can be fixed to the housing 21 by fastening a fixing ring, which is attached to the outer peripheral portion of the first lens portion 23, to the first portion 211 of the housing 21 with screws or the like.

[0060] The second lens portion 24 is an imaging optical system that images the light L passing through the Fabry-Perot interference filter 10 and emitted from the emission portion 21b. The second lens portion 24 includes at least one lens, and in this example, includes three lenses 24a, 24b, and 24c (lens group) arranged along the optical axis direction D. The second lens portion 24 is attached and fixed to the second portion 212 of the housing 21 at an outer peripheral portion of the second lens portion 24. Note that the second lens portion 24 can be fixed to the housing 21 by fastening a fixing ring, which is attached to the outer peripheral portion of the second lens portion 24, to the second portion 212 of the housing 21 with screws or the like.

[0061] The camera unit 5 includes the housing 51 and the image pickup element 52 disposed within the housing 51. The housing 51 includes a body portion 51a having a bottom surface and the attachment portion 51b. The attachment portion 51b is formed in a cylindrical shape one size smaller than the body portion 51a. The attachment portion 51b is detachably engaged with the attachment portion 21c of the lens unit 2 described above.

[0062] The image pickup element 52 is arranged within the body portion 51a of the housing 51. The image pickup element 52 is, for example, an InGaAs image sensor. The image pickup element 52 has a light-receiving surface 52a arranged on an imaging plane of the light L formed by the second lens portion 24, and images the light L emitted from the emitting portion 21b. Furthermore, a control circuit for controlling the image pickup element 52, an image processing circuit for processing an image captured by the image pickup element 52, a cooling mechanism for cooling the image pickup element 52, and the like are arranged within the body portion 51a. Fig. 1, these components are designated by the reference numeral 53.

[0063] In the hyperspectral camera 1, the light L incident from the incident section 21a is focused by the first lens section 23 and travels towards the filter unit 30 (see Fig. 1 and Fig. 3). The light L traveling towards the filter unit 30 passes or penetrates successively the second aperture P2, the first aperture P1, the mirror sections 14 and 15 and the bandpass filter 32 (see Fig. 1, Fig. 3 and Fig. 5). The light L is spectrally separated according to wavelength as it passes through the Fabry-Perot interference filter 10 (mirror sections 14 and 15). The light L emitted by the filter unit 30 (bandpass filter 32) is imaged by the second lens section 24 onto the light-receiving surface 52a of the image pickup element 52 and recorded by the image pickup element 52.

[0064] In the hyperspectral camera 1, the Fabry-Perot interference filter 10 (first aperture P1) is arranged at a position where a principal ray passing through an outer edge Ra of an imaging range R of the light L formed by the second lens portion 24 intersects the optical axis A. Namely, the Fabry-Perot interference filter 10 is arranged at the position of a diaphragm of the optical system 22 and functions as a diaphragm. In this example, the optical system 22 is configured as a double-sided non-telecentric optical system, and the Fabry-Perot interference filter 10 is arranged away from the first lens portion 23 by the focal length of the first lens portion 23 and away from the second lens portion 24 by the focal length of the second lens portion 24.The Fabry-Perot interference filter 10 is arranged so that the incident position of the light L on the first aperture P1 coincides with the position at which the principal ray passing through the outer edge Ra of the imaging region R intersects the optical axis A. Note that the principal ray is a ray passing through the center of the diaphragm (first aperture P1).

[0065] In the hyperspectral camera 1, a width (spot width) of the light L at an incident position at the first aperture P1 is wider than the width of the first aperture P1, as viewed in the optical axis direction D. Accordingly, the light L traveling toward the Fabry-Perot interference filter 10 (mirror portions 14 and 15) can be narrowed by the first aperture P1. In this example, the light L has a circular shape with a diameter of 1.6 mm at the incident position at the first aperture P1, and the first aperture P1 has a circular shape with a diameter of 1.5 mm. As viewed in the optical axis direction D, the area of ​​a light incident region L at the incident position at the first aperture P1 can be equal to or less than 110% of the area of ​​the first aperture P1.Note that, in the present embodiment, the width of the light L at the incident position at the first aperture P1 is larger than the width of the first aperture P1 in all directions perpendicular to the optical axis direction D; however, it is sufficient if the width of the light L at the incident position at the first aperture P1 is larger than the width of the first aperture P1 in at least one direction perpendicular to the optical axis direction D.

[0066] Fig. 6 is a view for describing the control of the angle of incidence by the first aperture P1 and the second aperture P2. In Fig. All elements are shown schematically in Figure 6. As described above, in the hyperspectral camera 1, the second aperture P2 is located with respect to the first aperture P1 on the side of the incidence section 21a (upper side in Fig. 6) and the diameter (width) of the second aperture P2 is larger than the diameter (width) of the first aperture P1. Therefore, the light L from the incident portion 21a passes through the second aperture P2 and then through the first aperture P1. In a case where the width of the light L at the incident position at the second aperture P2 when viewed in the optical axis direction D is larger than the width of the second aperture P2, the light L from the incident portion 21a is narrowed by the second aperture P2 and is then narrowed by the first aperture P1. By thus employing a double aperture structure in which the first aperture P1 and the second aperture P2 are provided, not only can the light L be narrowed by the first aperture P1, but also the angle of incidence of the light L with respect to the Fabry-Perot interference filter 10 can be controlled by the second aperture P2.

[0067] For example, if the thickness (depth) of the second aperture P2, as in Fig. 6 (a), the light L can be incident on the Fabry-Perot interference filter 10 at a relatively large angle of incidence. On the other hand, if the thickness of the second aperture P2 is as shown in Fig. 6 (b) is enlarged / thick, the incidence of the light L with a relatively large angle of incidence on the Fabry-Perot interference filter 10 is increased compared to the case in Fig. 6 (a). In this way, the angle of incidence of the light L with respect to the Fabry-Perot interference filter 10 can be controlled by adjusting the thickness of the second aperture P2. [Functions and effects]

[0068] In the lens unit 2, the width of the light L at the incident position at the first aperture P1, as viewed in the optical axis direction D, is larger than the width of the first aperture P1. Accordingly, for example, compared with the case where the light L narrowed by a lens to a width narrower than the width of the first aperture P1 passes through the first aperture P1, the width of the first aperture P1 can be maximized and the amount of light can be ensured. In addition, the light L traveling toward the Fabry-Perot interference filter 10 can be narrowed by the first aperture P1, and the depth of field can be increased. The influence of focus shift can be reduced by increasing the depth of field. In addition, the first aperture P1 is formed integrally with the Fabry-Perot interference filter 10.Accordingly, compared to, for example, forming the first aperture P1 separately from the Fabry-Perot interference filter 10, the occurrence of design deviations (e.g., a deviation in the distance or angle between the pair of mirror sections 14 and 15 and the first aperture P1, misalignment in a direction perpendicular to the optical axis A, or the like) can be suppressed. As described above, the lens unit 2 of the hyperspectral camera 1 enables satisfactory image capture. In addition, since the Fabry-Perot interference filter 10 forms the lens unit 2, and the lens unit 2 and the camera unit 5 can be attached to and detached from each other, the degree of freedom in selecting the camera unit 5 can be increased.In addition, since the Fabry-Perot interference filter 10 is arranged between the first lens section 23 and the second lens section 24, the total length along the optical axis direction D can be shortened, for example, compared to an arrangement of the Fabry-Perot interference filter 10 between the second lens section 24 and the camera unit 5.

[0069] The Fabry-Perot interference filter 10 is arranged at a position where a principal ray passing through the outer edge Ra of the imaging area R of the light L shaped by the second lens portion 24 intersects the optical axis A. Accordingly, the size of the imaging area R of the light L shaped by the second lens portion 24 can be kept constant regardless of the size of the first aperture P1. Therefore, the image pickup element 52 can be used regardless of the size of the first aperture P1. In addition, since the angle of incidence of the light L on the Fabry-Perot interference filter 10 becomes constant, the wavelength shift in the Fabry-Perot interference filter 10 can be easily corrected.

[0070] The first aperture P1 is located on the side of the incident portion 21a with respect to the mirror portions 14 and 15. Accordingly, stray light or light with a large angle of incidence can be cut off by the first aperture P1 before it hits the mirror portions 14 and 15, and noise can be reduced.

[0071] The optical system 22 includes the second aperture P2 disposed between the Fabry-Perot interference filter 10 and the first lens portion 23. Accordingly, the light L can be narrowed to a desired angular range by the first aperture P1 and the second aperture P2, and the resolution in capturing an image for each wavelength can be improved. Since the first aperture P1 is integrally formed with the Fabry-Perot interference filter 10, it is difficult to increase the thickness (depth) of the first aperture P1. In this regard, it is advantageous to provide a second aperture P2 in addition to the first aperture P1 because the thickness of the second aperture P2 can be adjusted more easily than that of the first aperture P1.

[0072] The second aperture P2 is formed as an opening 36 formed in the support 31, and the Fabry-Perot interference filter 10 is fixed to the support 31. Accordingly, the Fabry-Perot interference filter 10 (first aperture P1) can be appropriately fixed near the second aperture P2.

[0073] The carrier 31 is sandwiched and fixed between the first portion 211 of the housing 21 (the first lens holder holding the first lens portion 23) and the second portion 212 of the housing 21 (the second lens holder holding the second lens portion 24). Accordingly, the carrier 31 can be adequately fixed.

[0074] Viewed in the optical axis direction D, the area of ​​the incident light L at the incident position at the first aperture P1 can be equal to or less than 110% of the area of ​​the first aperture P1. In this case, the light utilization efficiency can be improved.

[0075] The Fabry-Perot interference filter 10 includes the substrate 11 having the first surface 11a and the second surface 11b, and the first laminated structure 12 disposed on the first surface 11a. The first laminated structure 12 includes the first laminate 122 disposed on the first surface 11a and including the mirror portion 14, and the second laminate 124 disposed on the opposite side of the substrate 11 with respect to the first laminate 122 and including the mirror portion 15. In this case, too, a satisfactory image can be captured with the hyperspectral camera 1.

[0076] The Fabry-Perot interference filter 10 includes the second laminated structure 13 disposed on the second surface 11b of the substrate 11, and the recess 18 is formed on the surface 13a of the second laminated structure 13 opposite the substrate 11. The recess 18 overlaps the first aperture P1 when viewed in the optical axis direction D. Therefore, since the recess 18 is formed, the light L can easily pass through a portion of the Fabry-Perot interference filter 10 that overlaps the first aperture P1, and the light utilization efficiency can be improved.

[0077] The first aperture P1 is formed by providing the light-shielding layer 135 in a region of the Fabry-Perot interference filter 10 outside the light-transmitting region 10a, while not providing the light-shielding layer 135 in the light-transmitting region 10a. Accordingly, the first aperture P1 can be formed integrally with the Fabry-Perot interference filter 10. [Modification examples]

[0078] As in a first modification example in Fig. 7, the optical system 22 may further include a reduction optical system 26 (additional optical system) that is arranged between the Fabry-Perot interference filter 10 and the first lens portion 23 and reduces the width of the light L. In this example, the reduction optical system 26 is arranged between the first lens portion 23 and the second aperture P2. The reduction optical system 26 includes, for example, a plurality of lenses. Also in the first modification example, similar to the above-described embodiment, a satisfactory image can be captured with the hyperspectral camera 1. In addition, the light utilization efficiency can be improved by reducing the width of the light L with the reduction optical system 26 before it hits the Fabry-Perot interference filter 10.

[0079] In a second modification example, which is shown in Fig. As shown in Fig. 8, the reduction optical system 26 is configured as an optical system that reduces the width of the light L and collimates / collects the light L (reduces the angle of incidence on the Fabry-Perot interference filter 10, namely, the angle with respect to the optical axis direction D). Namely, the reduction optical system 26 makes the angle of incidence of the light L on the Fabry-Perot interference filter 10 smaller than the angle of the light L traveling from the first lens portion 23 toward the Fabry-Perot interference filter 10 (reduction optical system 26). Furthermore, the optical system 22 includes another optical system 27 disposed between the Fabry-Perot interference filter 10 and the second lens portion 24, which returns the angle of the light L to a pre-collimation angle (returns the angle with respect to the optical axis direction D to an original angle).In the second modification example, similar to the above-described embodiment, an image can be satisfactorily captured by the hyperspectral camera 1. In addition, the light utilization efficiency can be improved by reducing the width of the light L before it hits the Fabry-Perot interference filter 10. Furthermore, the occurrence of wavelength shift can be suppressed by collimating the light L before it hits the Fabry-Perot interference filter 10. Note that in the second modification example, the optical system 22 may include an additional optical system that collimates the light L without reducing the width of the light L. In this case, too, the occurrence of wavelength shift can be suppressed.

[0080] Instead of the Fabry-Perot interference filter 10, a Fabry-Perot interference filter 400 of a third modification example shown in Fig. 9. The Fabry-Perot interference filter 400 includes a substrate layer 411 (first substrate), a mirror portion 412, and a driving electrode 413. The substrate layer 411 has a surface 411a and a surface 411b facing each other. The substrate layer 411 is made of a light-transmitting material. The mirror portion 412 is, for example, a metal foil, a dielectric multilayer film, or a composite film thereof. The driving electrode 413 is made of, for example, a metal material.

[0081] The Fabry-Perot interference filter 400 further includes a substrate layer 421 (second substrate), a mirror portion 422, and a drive electrode 423. The substrate layer 421 has a surface 421a and a surface 421b facing each other. The substrate layer 421 is made of a light-transmitting material. The mirror portion 422 is, for example, a metal layer, a dielectric multilayer film, or a composite film thereof. The drive electrode 423 is made of, for example, a metallic material.

[0082] A recess 414 is formed on the surface 411a of the substrate layer 411. A protrusion 415 is provided on a bottom surface 414a of the recess 414. Taking the bottom surface 414a as a reference, a height of an end surface 415a of the protrusion 415 is lower than a height of the surface 411a of the substrate layer 411. The mirror portion 412 is provided on the end surface 415a (first surface) of the protrusion 415. The drive electrode 413 is provided on the bottom surface 414a of the recess 414 so as to surround the protrusion 415. The drive electrode 413 is electrically connected to an electrode pad (not shown) via, for example, a wiring (not shown) provided on the substrate layer 411. The electrode pad is provided, for example, in a region of the substrate layer 411 that is accessible from the outside.

[0083] The surface 421b of the substrate layer 421 is bonded to the surface 411a of the substrate layer 411 by plasma welding, for example. The mirror portion 422 and the drive electrode 423 are provided on the surface 421b (second surface) of the substrate layer 421. The surface 421b of the substrate layer 421 faces the end surface 415a of the substrate layer 411 in the optical axis direction D. The mirror portion 422 faces the mirror portion 412 with the air gap S therebetween in the optical axis direction D. The drive electrode 423 is provided on the surface 421b of the substrate layer 421 so as to surround the mirror portion 422 and faces the drive electrode 413 with the air gap S therebetween. The drive electrode 423 is electrically connected to an electrode pad (not shown) via, for example, a wiring (not shown) provided on the substrate layer 421.The electrode pad is provided, for example, in a region of the substrate layer 421 that is accessible from the outside.

[0084] A groove 424 is formed on the surface 421a of the substrate layer 421, surrounding the mirror portion 422 and the drive electrode 423 as viewed in the optical axis direction D. The groove 424 extends in a ring shape. A portion of the substrate layer 421 surrounded by the groove 424 is movable in a direction in which the pair of mirror portions 412 and 422 face each other, and a portion in which the groove 424 is formed serves as a diaphragm-shaped holding portion 425.

[0085] In addition, the holding portion 425 may be formed in a diaphragm shape by forming a groove on the surface 421a and / or on the surface 421b of the substrate layer 421, which groove surrounds the mirror portion 422 and the drive electrode 423 as viewed in the optical axis direction D. A holding portion having a diaphragm shape may be formed in the substrate layer 411 by forming a groove in the substrate layer 411, which groove surrounds the mirror portion 412 and the drive electrode 413 as viewed in the optical axis direction D. Instead of the holding portion having a diaphragm shape, the holding portion may be formed as a plurality of radially arranged columns.

[0086] In the Fabry-Perot interference filter 400, when a potential difference is generated between the driving electrode 413 and the driving electrode 423 by applying a voltage to the driving electrode 413 and the driving electrode 423, an electrostatic force corresponding to the potential difference is generated between the driving electrode 413 and the driving electrode 423. Due to the generation of an electrostatic force between the driving electrode 413 and the driving electrode 423, the portion of the substrate layer 421 surrounded by the groove 424 is attracted to one side of the substrate layer 411, and the distance between the mirror portion 412 and the mirror portion 422 is adjusted. Accordingly, light with a wavelength corresponding to the distance between the mirror portion 412 and the mirror portion 422 passes through the Fabry-Perot interference filter 400.

[0087] Even if the Fabry-Perot interference filter 400 of the third embodiment is used instead of the Fabry-Perot interference filter 10, an image can be satisfactorily captured with the hyperspectral camera 1, similar to the above-described embodiment. In addition, in the Fabry-Perot interference filter 400, the first aperture P1 may be formed integrally with the Fabry-Perot interference filter 400, for example, by forming a light-shielding layer on the surface 411b of the substrate layer 411 opposite to the substrate layer 421. Similar to the above-described embodiment, the first aperture P1 may be formed by providing a light-shielding layer in a region of the Fabry-Perot interference filter 400 outside a light-transmitting region, while not providing the light-shielding layer in the light-transmitting region.Alternatively, the first aperture P1 may be formed integrally with the Fabry-Perot interference filter 400 by forming a light-shielding layer on the surface 421a of the substrate layer 421 opposite to the substrate layer 411. In this case, the first aperture P1 is located on a side opposite the incident portion 21a with respect to the mirror portions 412 and 422 of the Fabry-Perot interference filter 400 (the side of the emission portion 21b).

[0088] In the above-described embodiment, the Fabry-Perot interference filter 10 is in contact with the carrier 31; however, as another modification example, as shown in Fig. As shown in Figure 10(a), the Fabry-Perot interference filter 10 may be arranged at a distance from the support 31. For example, an air gap may be formed between the Fabry-Perot interference filter 10 and the support 31, or a glass member may be arranged between the Fabry-Perot interference filter 10 and the support 31. When the Fabry-Perot interference filter 10 is arranged at a distance from the support 31, the effect of suppressing the angle of incidence by the double-aperture structure described above is clearly apparent.

[0089] As in Fig. As shown in Fig. 10(b), the first aperture P1 may be arranged on the side opposite to the incident portion 21a (the emission portion 21b side) with respect to the mirror portions 14 and 15 of the Fabry-Perot interference filter 10. In this case, the light L passing through the Fabry-Perot interference filter 10 passes through the first aperture P1. For example, in the above-described embodiment, such an arrangement can be realized by attaching the Fabry-Perot interference filter 10 to the support 31 in a direction opposite to the optical axis direction D.Alternatively, instead of forming the light-shielding layer 135 on the side of the incident portion 21a with respect to the mirror portions 14 and 15 to provide the first aperture P1 in the above-described embodiment, the above-described arrangement can also be realized by forming the light-shielding layer 135 on the side of the incident portion 21a opposite to the mirror portions 14 and 15 (for example, on a surface of the Fabry-Perot interference filter 10 opposite to the incident portion 21a) to provide the first aperture P1.

[0090] As in Fig. As shown in Figure 11(a), the second aperture P2 may be disposed on the side of the incident portion 21a (the side of the emission portion 21b) opposite the mirror portions 14 and 15 of the Fabry-Perot interference filter 10. Namely, the second aperture P2 may be disposed between the Fabry-Perot interference filter 10 and the second lens portion 24.

[0091] As in Fig. As shown in Fig. 11(b), both the first aperture P1 and the second aperture P2 may be arranged on the side opposite to the incident portion 21a (emission portion 21b side) with respect to the mirror portions 14 and 15 of the Fabry-Perot interference filter 10.

[0092] As in Fig. 12 (a) and (b), the diameter (width) of the second aperture P2 may be smaller than the diameter (width) of the first aperture P1 when the second aperture P2 is arranged on the side opposite to the incident portion 21a with respect to the mirror portions 14 and 15 of the Fabry-Perot interference filter 10. With the modification examples described above, which are also shown in the Fig. 10 to 12, an image can be satisfactorily captured by the hyperspectral camera 1, similarly to the above-described embodiment.

[0093] In the Fig.In the hyperspectral camera 1 shown in FIG. 13, the first lens portion 23 does not focus the light L traveling from the incident portion 21a toward the Fabry-Perot interference filter 10, but collimates the light L. In this example, the first lens portion 23 includes four lenses 23a, 23b, 23c, and 23d arranged along the optical axis direction D. The second lens portion 24 includes six lenses 24a, 24b, 24c, 24d, 24e, and 24f arranged along the optical axis direction D. Even with such a modification example, similar to the above-described embodiment, an image can be satisfactorily captured with the hyperspectral camera 1.

[0094] The present disclosure is not limited to the above-described embodiment and modification examples. For example, the material and shape of each configuration are not limited to the above-described material and shape, and various materials and shapes can be used.

[0095] The Fabry-Perot interference filter 10 does not need to be attached to the support 31, but may be attached to a member separate from the member in which the second aperture P2 is formed. The second aperture P2 does not need to be formed as an opening 36 formed in the support 31, and, for example, a aperture part in which an opening forming the second aperture P2 is formed may be provided separately from the support 31. The second aperture P2 may be omitted.

[0096] The method for fixing the carrier 31 is not limited to the example described above, and the carrier 31 may not be sandwiched and fixed between the first portion 211 of the housing 21 and the second portion 212 of the housing 21. In the above-described embodiment, the first lens holder that holds the first lens portion 23 is formed by the first portion 211 of the housing 21, and the second lens holder that holds the second lens portion 24 is formed by the second portion 212 of the housing 21; however, the first lens holder and the second lens holder may be provided separately from the housing 21. In this case, too, the carrier 31 may be sandwiched and fixed between the first lens holder and the second lens holder. The housing 21 may not be divided in the optical axis direction D and may be formed of a single part.In this case too, the carrier 31 can be fixed to the housing 21.

[0097] Viewed in the optical axis direction D, the area of ​​the incident region of light L at the incident position at the first aperture P1 can be larger than 110% of the area of ​​the first aperture P1. Viewed in the optical axis direction D, the width of light L at the incident position at the second aperture P2 can be narrower than the width of the second aperture P2. Therefore, the light L does not necessarily have to be narrowed by the second aperture P2.

[0098] It is sufficient if at least a part of the recess 18 overlaps the first aperture P1 in the optical axis direction D, and if, as viewed in the optical axis direction D, an outer edge of the recess 18 may be located outside an outer edge of the first aperture P1, or the outer edge of the first aperture P1 may be located outside the outer edge of the recess 18. In the above-described embodiment, the light-shielding layer 135 may not be formed over the entire surface 13a of the second laminated structure 13, and as viewed in the Z direction, the outer edge of the first aperture P1 may be located outside the outer edge of the recess 18. The recess 18 may not be provided. An optical device other than the camera unit 5 may be attached to the attachment portion 21c of the housing 21.The hyperspectral camera 1 may further include a ring light source for supplementing the amount of light, which is arranged to face the incident portion 21a of the lens unit 2. List of reference symbols

[0099] 1: Hyperspectral camera, 2: Lens unit (Hyperspectral camera lens unit), 5: Camera unit (Optical device), 10: Fabry-Perot interference filter, 10a: Light transmission region, 11: Substrate, 11a: First surface, 11b: Second surface, 12: First laminated structure, 122: First laminate, 124: Second laminate, 13: Second laminated structure, 13a: Surface, 135: Light shielding layer, 14, 15: Mirror portion, 18: Recess, 21: Housing, 21a: Incident portion, 21b: Emission portion, 21c: Mounting portion, 22: Optical system, 23: First lens portion, 24: Second lens portion, 26: Reduction optical system (additional optical system), 31: Carrier, 36: Aperture, 52: Image pickup element, 400: Fabry-Perot interference filter, 411: substrate layer (first substrate), 412, 422: mirror section, 415a: end face (first surface), 421: substrate layer (second substrate), 421b: surface (second surface), P1: first aperture, P2: second aperture, A: optical axis,D: optical axis direction, L: light, R: imaging area, Ra: outer edge., QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2016 - 119 86 A

[0002]

Claims

[1] Hyperspectral camera lens unit comprising: a housing having an incident portion onto which light is incident, an emitting portion from which the light is emitted, and a mounting portion to which an optical device is detachably attached; and an optical system arranged within the housing, where the optical system comprises: a Fabry-Perot interference filter comprising a pair of mirror sections with a variable distance therebetween and transmitting the light from the incident section according to the distance between the pair of mirror sections; a first aperture formed integrally with the Fabry-Perot interference filter and through which the light traveling toward the Fabry-Perot interference filter or the light passing through the Fabry-Perot interference filter passes; a first lens section that focuses or collimates the light traveling from the incident section toward the Fabry-Perot interference filter; and a second lens section which images the light passing through the Fabry-Perot interference filter and emitted by the emission section, wherein, viewed in the optical axis direction, a width of the light at an incident position at the first aperture is greater than a width of the first aperture. [2] The hyperspectral camera lens unit according to claim 1, wherein the Fabry-Perot interference filter is arranged at a position where a chief ray passing through an outer edge of an imaging region of the light shaped by the second lens portion intersects an optical axis of the light. [3] The hyperspectral camera lens unit according to claim 1 or 2, wherein the first aperture is arranged on one side of the incident portion with respect to the pair of mirror portions. [4] The hyperspectral camera lens unit according to any one of claims 1 to 3, wherein the optical system further comprises a second aperture arranged between the Fabry-Perot interference filter and the first lens portion or between the Fabry-Perot interference filter and the second lens portion. [5] Hyperspectral camera lens unit according to claim 4, wherein the second aperture is formed as an opening formed in a carrier, and the Fabry-Perot interference filter is attached to the carrier. [6] Hyperspectral camera lens unit according to claim 5, further comprising: a first lens holder holding the first lens portion; and a second lens holder holding the second lens section, wherein the carrier is sandwiched and fixed between the first lens holder and the second lens holder. [7] The hyperspectral camera lens unit according to any one of claims 1 to 6, wherein, viewed in the optical axis direction, an area of ​​a light incident region at an incident position at the first aperture is equal to or smaller than 110% of an area of ​​the first aperture. [8] The hyperspectral camera lens unit according to any one of claims 1 to 7, wherein the optical system further comprises an additional optical system disposed between the Fabry-Perot interference filter and the first lens portion and reducing the width of the light. [9] The hyperspectral camera lens unit according to any one of claims 1 to 7, wherein the optical system further comprises an additional optical system disposed between the Fabry-Perot interference filter and the first lens portion and collimating the light. [10] The hyperspectral camera lens unit of claim 9, wherein the additional optical system reduces the width of the light. [11] Hyperspectral camera lens unit according to one of claims 1 to 10, wherein the Fabry-Perot interference filter comprises a substrate having a first surface and a second surface opposite the first surface and a first laminated structure disposed on the first surface, and the first laminated structure comprises a first laminate disposed on the first surface and having one of the pair of mirror portions, and a second laminate disposed on a side opposite to the substrate with respect to the first laminate and having the other of the pair of mirror portions. [12] Hyperspectral camera lens unit according to claim 11, wherein the Fabry-Perot interference filter further comprises a second laminated structure disposed on the second surface of the substrate, a recess is formed on a surface of the second laminated structure opposite to the substrate, and at least a part of the recess overlaps the first aperture as seen in the optical axis direction. [13] The hyperspectral camera lens unit according to any one of claims 1 to 10, wherein the Fabry-Perot interference filter comprises a first substrate having a first surface, a second substrate having a second surface opposite to the first surface, one of the pair of mirror portions formed on the first surface, and the other of the pair of mirror portions formed on the second surface. [14] The hyperspectral camera lens unit according to any one of claims 1 to 13, wherein the first aperture is formed by providing a light-shielding layer in a region of the Fabry-Perot interference filter other than the light-transmitting region, while the light-shielding layer is not provided in the light-transmitting region. [15] Hyperspectral camera that has: the hyperspectral camera lens unit according to any one of claims 1 to 14; and a camera unit which is the optical device mounted on the mounting portion of the housing, the camera unit including an image pickup element which images the light emitted from the emitting portion.

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