JP6237161B2 - Imaging device - Google Patents

Description

  The present invention relates to an imaging apparatus capable of acquiring an image of an object corresponding to a plurality of optical characteristics by a single imaging.

  One imaging device is a so-called multi-imaging camera (see, for example, Patent Document 1). As one form of multi-imaging camera, a small lens array is arranged after the intermediate image of the object or directly after the object image, and a plurality of object images corresponding to the number of small lenses are formed on the imaging surface. There is something. Each small lens is provided with a different spectral filter, and each of a plurality of object images is formed by a predetermined wavelength component. By capturing a plurality of object images formed by these predetermined wavelength components with an image sensor and performing image processing, it is possible to acquire a two-dimensional spectral characteristic of the object with a single imaging.

International Publication No. 2012/066741 Pamphlet

  In such a multi-imaging camera, parallax occurs when the object deviates from the in-focus position, so that not only the object image is simply blurred but also color misregistration occurs.

  The present invention has been made in view of such a problem, and an object thereof is to provide an imaging apparatus capable of obtaining a highly accurate image of an object corresponding to a plurality of optical characteristics.

  In order to achieve such an object, according to an embodiment of the present invention, an imaging optical system that forms an intermediate image of the object by transmitting the light from the object, and the light from the imaging optical system. A collimator optical system that makes substantially parallel light and a plurality of optical elements that are two-dimensionally arranged along a plane perpendicular to the optical axis, and the light that has become substantially parallel light by the collimator optical system. An optical element array that passes through the element, a lens array that refracts the light that has passed through the collimator optical system and the optical element array, and a plane that is conjugated with the optical element array by the lens array, or the imaging optical system An image sensor that is disposed on a plane conjugate with the intermediate image and detects light from the lens array, and light of the optical element based on a detection signal output from the image sensor. A light diffusing element for diffusing light from the imaging optical system toward the collimator optical system on an image plane of the imaging optical system. An imaging device is provided that is arranged.

  According to the present invention, it is possible to obtain a highly accurate image of an object corresponding to a plurality of optical characteristics.

1 is a schematic configuration diagram of an imaging apparatus according to a first embodiment. It is an enlarged view of the optical filter array which concerns on 1st Embodiment. It is an enlarged view of a lens array and an image sensor. It is a graph which shows the spectral characteristics in nine optical filters. It is an optical path diagram showing an example in which the image side of the imaging optical system is not telecentric. It is an optical path diagram showing an example in which the image side of the imaging optical system is telecentric. It is a schematic block diagram of the imaging device which concerns on 2nd Embodiment. It is an enlarged view of the optical filter array which concerns on 2nd Embodiment. It is a schematic diagram which shows the object image on the detection surface of an image sensor. It is a schematic block diagram of the imaging device which concerns on 3rd Embodiment. It is a graph which shows the light distribution characteristic of diffused light. It is a schematic block diagram which shows a part of microscope.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. An imaging apparatus (multi-imaging camera) 1 according to the first embodiment is shown in FIG. The imaging apparatus 1 according to the first embodiment includes an imaging optical system 10, a light diffusing element 15, a detection unit 20, and an image processing unit 40. The imaging optical system 10 includes an imaging lens 11 and a diaphragm 12 and forms an intermediate image Im1 (real image) of the object OB1 by transmitting light from the object OB1. The imaging lens 11 is schematically depicted as a single lens in FIG. 1, but may be composed of a plurality of lenses. The diaphragm 12 is formed in a disk shape having an opening 12a in the center, and is disposed in the vicinity of the object side of the imaging lens 11 when the imaging lens 11 is a single lens. When the imaging lens 11 is composed of a plurality of lenses, the diaphragm 12 may be disposed between the plurality of lenses.

  A light diffusing element 15 is provided on the image side of the imaging optical system 10 (imaging lens 11). The light diffusing element 15 is configured using, for example, a diffusing lens array (not shown) including a plurality of convex diffusing microlenses (not shown) capable of diffusing light, and an imaging lens. 11 diffuses light toward the detection unit 20. The light diffusing element 15 is disposed such that the diffusing surface 16 formed on the light diffusing element 15 is positioned on the image plane of the imaging optical system 10.

  The detection unit 20 is provided on the image side of the light diffusing element 15. The detection unit 20 includes a collimator optical system 21, an optical filter array 25, a lens array 30, and an image sensor 35. The collimator optical system 21 includes a collimator lens 22 and a condenser lens 23. The collimator lens 22 is provided between the imaging optical system 10 and the light diffusing element 15 and the optical filter array 25 so that the light from the imaging optical system 10 and the light diffusing element 15 can be made substantially parallel light. It has become. The condensing lens 23 is provided between the optical filter array 25 and the lens array 30, and can transmit the light from the optical filter array 25 to form an image (real image) of the object OB1. Yes. Although the collimator lens 22 and the condensing lens 23 are schematically depicted as single lenses in FIG. 1, they may be composed of a plurality of lenses.

  The optical filter array 25 is provided between the collimator lens 22 and the condenser lens 23 so that the center of the optical filter array 25 is positioned on the optical axis Ax1. For example, as shown in FIG. 2, the optical filter array 25 includes nine optical filters from a first optical filter 26a to a ninth optical filter 26i arranged two-dimensionally along a plane perpendicular to the optical axis Ax1. And a holding member (not shown) for holding them. As shown in FIG. 4, the first optical filter 26a to the ninth optical filter 26i are band-pass filters each having nine wavelengths from the first wavelength λ1 to the ninth wavelength λ9 as center wavelengths.

  A lens array 30 is disposed on the image plane of the condenser lens 23. As shown in FIG. 3, the lens array 30 includes tens of thousands to millions of microlenses 31 having a positive refractive power and two-dimensionally arranged along a plane perpendicular to the optical axis Ax1. The

  The image sensor 35 is disposed on a plane having a conjugate relationship with the optical filter array 25 by the plurality of microlenses 31. As shown in FIG. 3, the image sensor 35 has a rectangular detection surface 36 in which hundreds of thousands to tens of millions of imaging pixels are two-dimensionally arranged on a plane. The detection surface 36 of the image sensor 35 is disposed on a surface conjugate with the optical filter array 25 by a plurality of microlenses 31, and images (real images) of the plurality of optical filter arrays 25 by the plurality of microlenses 31 are detection surfaces 36. Formed on top. The relative position of the lens array 30 and the image sensor 35 is adjusted so that an image (real image) of the optical filters 26a to 26i constituting the optical filter array 25 is formed for each of one or a plurality of imaging pixels. Is done. As such an image sensor 35, for example, a CCD or a CMOS is used.

  The image sensor 35 detects images of a plurality of optical filter arrays 25 formed on the detection surface 36 (that is, images of a plurality of sets of optical filters 26 a to 26 i), and outputs detection signals to the image processing unit 40. Based on the detection signal output from the image sensor 35, the image processing unit 40 multi-band image (that is, a predetermined wavelength) of the object OB1 corresponding to each wavelength characteristic of the first optical filter 26a to the ninth optical filter 26i. 2D spectral characteristic information of the object in the range) is generated.

  In the imaging device 1 of the first embodiment, the light beam R1 from the object OB1 located at a distant place passes through the imaging lens 11 of the imaging optical system 10 and forms an image on the diffusion surface 16 of the light diffusing element 15. The intermediate image Im1 (real image) of the object OB1 is formed on the diffusion surface 16 of the light diffusing element 15. At this time, the spread angle of the light beam R1 from the object OB1 is limited by the opening 12a of the diaphragm 12. Further, since the light beam R1 from the object OB1 is diffused and emitted on the diffusion surface 16 of the light diffusing element 15 where the intermediate image Im1 of the object OB1 is formed, this is equivalent to the presence of the object OB1 on the diffusion surface 16. become. Thereby, the intermediate image Im1 of the object OB1 formed on the diffusing surface 16 of the light diffusing element 15 can be detected by the detecting unit 20.

  The diffused light beam R1 ′ from the diffusing surface 16 is transmitted through the collimator lens 22 of the collimator optical system 21, and becomes a substantially parallel light beam whose principal ray is bent to the optical axis Ax1 side. The light beam R1 ′ from the diffusing surface 16 that has become a substantially parallel light beam by the collimator lens 22 passes through one of the first optical filter 26a to the ninth optical filter 26i in the optical filter array 25. The light beam R 1 ′ from the diffusing surface 16 that has passed through the optical filter array 25 passes through the condenser lens 23 of the collimator optical system 21 and is condensed on the lens array 30, and any of the plurality of microlenses 31 in the lens array 30. The light passes through the light and enters the detection surface 36 of the image sensor 35.

  As described above, the detection surface 36 of the image sensor 35 is arranged on a surface that is conjugate with the optical filter array 25 by the plurality of microlenses 31. Therefore, the images of the plurality of optical filter arrays 25 formed by the plurality of microlenses 31 are formed on the detection surface 36 of the image sensor 35. Also, the relative position of the lens array 30 and the image sensor 35 so that light from any one of the first optical filter 26a to the ninth optical filter 26i is incident on each imaging pixel of the image sensor 35. Has been adjusted. Therefore, for each imaging pixel of the image sensor 35, it is possible to specify which of the first optical filter 26a to the ninth optical filter 26i is the detection signal of the transmitted light.

  The image sensor 35 detects images of a plurality of optical filter arrays 25 formed on the detection surface 36 (that is, images of a plurality of sets of optical filters 26 a to 26 i), and outputs detection signals to the image processing unit 40. Since the first optical filter 26a to the ninth optical filter 26i are band-pass filters having nine types of wavelengths as the central wavelengths, the light beams collected on the lens array 30 are spectrally detected into nine types of wavelength bands and detected. can do. Thereby, a spectral distribution as shown in FIG. 4 can be obtained for each imaging pixel corresponding to one microlens 31.

  The image processing unit 40 generates a multi-wavelength band image of the object OB1 based on the detection signal output from the image sensor 35. At this time, the image processing unit 40 generates an image of the object OB1 for each detection signal of the imaging pixels corresponding to the first optical filter 26a to the ninth optical filter 26i. In this way, a multi-wavelength band image of the object OB1 corresponding to each wavelength characteristic of the first optical filter 26a to the ninth optical filter 26i is acquired and acquired. Note that the multi-wavelength band image of the object OB1 generated by the image processing unit 40 is observed using an image display device (not shown) or the like.

  The conventional multi-imaging camera has the following problems. First, parallax occurs when the object (subject) deviates from the in-focus position, so that not only the object image is simply blurred but also color misregistration occurs. Second, the wavelength of the light beam reaching the image sensor is determined by the position of the pupil of the optical system where the light beam is incident. Therefore, an accurate multi-wavelength band image may not be obtained for an object (subject) in which reflected light with high directivity, such as metallic paint or pearl paint for automobiles, is generated. Third, when a multi-imaging camera is used for a microscope, a sufficiently large pupil cannot be obtained, and thus the light beam cannot be divided at the position of the pupil.

  Here, the third problem will be described in detail. FIG. 12 shows a state in which the minute object OB2 is magnified and observed with a microscope. In the microscope shown in FIG. 12, an enlarged real image I1 of the minute object OB2 is formed by the objective lens 501, and an enlarged virtual image I2 of the real image I1 is formed by the eyepiece 502. At this time, the numerical aperture NA of the objective lens 501 is expressed by the following equation (1), where the refractive index of air is 1.

  sinθ1 = NA (1)

  Further, when the magnification of the virtual image I2 with respect to the minute object OB2 is r, the relationship of the following expression (2) is established.

  sinθ2≈NA / r (2)

  Therefore, in the eye point plane E where the light beam from the virtual image I2 gathers, the diameter d of the light beam is approximately expressed by the following equation (3).

  d≈2 × L × sin θ2≈2 × L × NA / r (3)

  The distance L is a distance from the virtual image I2 to the eye point plane E, and is usually about 250 mm. Here, consider a case where the magnification r of the microscope is high. As an example, assume L = 250 mm, NA = 0.9, r = 100. If it does so, it will be set to d = 4.5mm from Formula (3). From formula (3), it can be seen that when the magnification r of the microscope is higher, the diameter d of the light beam becomes smaller. Therefore, in the pupil division type multi-imaging camera, it is difficult to divide the pupil and arrange different optical filters for each.

  With respect to the first problem described above, according to the present embodiment, the imaging optical system 10 forms an intermediate image Im1 (real image) of the object OB1 on the light diffusing element 15, and the intermediate image Im1 is detected by the detection unit 20. Detect with. At this time, since the light beam incident on the light diffusing element 15 is diffused after passing through the light diffusing element 15, it is equivalent to the presence of the object OB1 on the light diffusing element 15. Therefore, if the in-focus position of the detection unit 20 is matched with the light diffusing element 15, no color shift due to defocusing occurs. As a result, when the object (subject) is deviated from the in-focus position, the object image is simply blurred, and color misregistration hardly occurs, so that a highly accurate multi-wavelength band image can be obtained.

  Further, with respect to the second problem described above, according to the present embodiment, even if a highly directional light beam is incident on the imaging optical system 10, the light beam is widely diffused by the light diffusing element 15, and after diffusion. The luminous flux of becomes low in directivity. Therefore, a highly accurate multi-wavelength band image can be obtained even for an object (subject) in which reflected light with high directivity is generated.

  Further, with respect to the third problem described above, according to the present embodiment, even if a thin light beam is incident on the light diffusing element 15, the light beam is expanded by the light diffusing element 15, so that the optical filter array 25 is used. Spectroscopy is possible. Therefore, even when an enlarged image of an object (subject) is detected, a highly accurate multi-wavelength band image can be obtained. In addition, even when a lens that narrows the light flux, such as a fisheye lens, is used as the imaging optical system, a highly accurate multi-wavelength band image can be obtained.

  As described above, according to the first embodiment, since the light diffusing element 15 is disposed on the image plane of the imaging optical system 10, it corresponds to each wavelength characteristic of the first optical filter 26 a to the ninth optical filter 26 i. In addition, it is possible to obtain a multi-wavelength band image of the highly accurate object OB1.

  The light diffusing element 15 is configured using a diffusing lens array including a plurality of diffusing microlenses. As a result, the diffusing surface 16 becomes finer and light can be diffused with uniform angular characteristics on the diffusing surface 16, so that a multi-wavelength band image can be obtained in which fine portions of the object OB1 can be satisfactorily observed.

  In the first embodiment described above, when the multilayer interference filter is used, the optical characteristics of the optical filters 26a to 26i may change depending on the incident angle of the light beam. Therefore, it is desirable that the light beam R1 ′ from the diffusing surface 16 is incident on the optical filters 26a to 26i. For this purpose, the diffusing surface 16 of the light diffusing element 15 is preferably on the focal plane of the collimator lens 22, and the principal ray of the light beam R1 ′ from the diffusing surface 16 is preferably parallel to the optical axis Ax1. That is, it is desirable that the optical system including the imaging optical system 10 and the light diffusing element 15 is configured to be telecentric.

  However, when the imaging optical system 10 is used as a camera lens, the image side of the imaging optical system 10 is often not telecentric as shown in FIG. In such a case, as shown in FIG. 6, the field lens 18 may be arranged near the image side (or object side) of the light diffusing element 15 so as to be telecentric.

  Next, a second embodiment of the imaging device will be described with reference to FIG. An imaging apparatus (multi-imaging camera) 51 according to the second embodiment includes an imaging optical system 10, a light diffusing element 15, a detection unit 70, and an image processing unit 90. In the second embodiment, since the imaging optical system 10 and the light diffusing element 15 have the same configuration as that of the first embodiment, the same reference numerals as those in the first embodiment are used and detailed description thereof is omitted. .

  Similar to the first embodiment, the light diffusion element 15 is provided on the image side of the imaging optical system 10, and the detection unit 70 is provided on the image side of the light diffusion element 15. The detection unit 70 includes a collimator optical system 71, an optical filter array 75, a lens array 80, and an image sensor 85. The collimator optical system 71 has a collimator lens 72. The collimator lens 72 is provided between the imaging optical system 10 and the light diffusing element 15 and the optical filter array 75 so that the light from the imaging optical system 10 and the light diffusing element 15 can be made substantially parallel light. It has become. Although the collimator lens 72 is schematically depicted as a single lens in FIG. 7, it may be composed of a plurality of lenses.

  As shown in FIG. 8, the optical filter array 75 includes nine optical filters from a first optical filter 76a to a ninth optical filter 76i arranged two-dimensionally along a plane perpendicular to the optical axis Ax2. It is comprised from the holding member (not shown) holding these. Similarly to the first embodiment, the first optical filter 76a to the ninth optical filter 76i are band-pass filters each having nine wavelengths from the first wavelength λ1 to the ninth wavelength λ9 as center wavelengths.

  A lens array 80 is provided on the image side of the optical filter array 75. As shown in FIG. 8, the lens array 80 includes 9 lenses from a first small lens 81a having a positive refractive power to a ninth small lens 81i arranged two-dimensionally along a plane perpendicular to the optical axis Ax2. Consists of small lenses. The first small lens 81a to the ninth small lens 81i have the same size as the first optical filter 76a to the ninth optical filter 76i, and the focal plane for each object at infinity is the same plane perpendicular to the optical axis Ax2. It is aligned with respect to the optical axis direction so that it can be formed above.

  The first small lens 81a is the first optical filter 76a, the second small lens 81b is the second optical filter 76b, the third small lens 81c is the third optical filter 76c, and the fourth small lens 81d is the fourth optical filter 76d. The fifth small lens 81e is the fifth optical filter 76e, the sixth small lens 81f is the sixth optical filter 76f, the seventh small lens 81g is the seventh optical filter 76g, and the eighth small lens 81h is the eighth optical filter. The ninth small lens 81i corresponds to the position of the ninth optical filter 76i with respect to the filter 76h. The first small lens 81a to the ninth small lens 81i receive the light beams that have passed through the first optical filter 76a and the ninth optical filter 76i, respectively, and independently form an image of the object OB1.

  An image sensor 85 is disposed on the focal plane of a plurality of small lenses 81a to 81i conjugate with the image plane (intermediate image Im1) of the imaging optical system 10. As shown in FIG. 9, the image sensor 85 has a rectangular detection surface 86 in which hundreds of thousands to tens of millions of imaging pixels are two-dimensionally arranged on a plane. The detection surface 86 of the image sensor 85 is disposed on the focal plane of the plurality of small lenses 81a to 81i, and nine object images Ia to Ii (images of the object OB1) by the first small lens 81a to the ninth small lens 81i are displayed. They are formed side by side on the detection surface 86. As such an image sensor 85, for example, a CCD or a CMOS is used.

  The image sensor 85 detects nine object images Ia to Ii formed on the detection surface 86 and outputs detection signals to the image processing unit 90. Based on the detection signal output from the image sensor 85, the image processing unit 90 generates a multi-wavelength band image of the object OB1 corresponding to each wavelength characteristic of the first optical filter 76a to the ninth optical filter 76i.

  In the imaging device 51 of the second embodiment, the light beam R2 from the object OB1 at a distant place passes through the imaging lens 11 of the imaging optical system 10 and forms an image on the diffusion surface 16 of the light diffusing element 15. The intermediate image Im1 (real image) of the object OB1 is formed on the diffusion surface 16 of the light diffusing element 15. At this time, the spread angle of the light beam R2 from the object OB1 is limited by the opening 12a of the stop 12. Further, since the light beam R2 from the object OB1 is diffused and emitted on the diffusing surface 16 of the light diffusing element 15 where the intermediate image Im1 of the object OB1 is formed, this is equivalent to the presence of the object OB1 on the diffusing surface 16. become. Thereby, the intermediate image Im1 of the object OB1 formed on the diffusion surface 16 of the light diffusing element 15 can be detected by the detection unit 70.

  The diffused light beam R2 ′ from the diffusing surface 16 is transmitted through the collimator lens 72 of the collimator optical system 71 and becomes a substantially parallel light beam whose principal ray is bent toward the optical axis Ax2. The light beam R <b> 2 ′ from the diffusing surface 16 that has become a substantially parallel light beam by the collimator lens 72 passes through any of the first optical filter 76 a to the ninth optical filter 76 i in the optical filter array 75 and reaches the lens array 80. The first small lens 81a to the ninth small lens 81i of the lens array 80 receive the light beams that have passed through the first optical filter 76a and the ninth optical filter 76i, respectively, and form an image of the object OB1 independently.

  As described above, the detection surface 86 of the image sensor 85 is disposed on the focal plane of the plurality of small lenses 81a to 81i conjugate with the image plane (intermediate image Im1) of the imaging optical system 10. Therefore, nine object images Ia to Ii are formed on the detection surface 86 of the image sensor 85 by the first small lens 81a to the ninth small lens 81i. Nine nine object images Ia to Ii formed on the detection surface 86 are respectively formed with corresponding spectral characteristics among the first optical filter 76a to the ninth optical filter 76i. The image sensor 85 detects nine object images Ia to Ii formed on the detection surface 86 and outputs detection signals to the image processing unit 90.

  The image processing unit 90 generates a multi-wavelength band image of the object OB1 based on the image signals of the object images Ia to Ii corresponding to the wavelength characteristics of the optical filters 76a to 76i output from the image sensor 85. In this way, a multi-wavelength band image of the object OB1 corresponding to each wavelength characteristic of the first optical filter 76a to the ninth optical filter 76i is acquired and acquired. Note that the multi-wavelength band image of the object OB1 generated by the image processing unit 90 is observed using an image display device (not shown) or the like.

  Thus, according to the second embodiment, the same effect as that of the first embodiment can be obtained. In addition, when the light beam R2 ′ from the diffusing surface 16 is converted into a parallel light beam by the collimator lens 72, chief rays incident on the small lenses 81a to 81i become parallel to each other. Therefore, in the state in which the object OB1 is focused, nine object images Ia to Ii (real images) having the same size and shape are formed on the detection surface 86 of the image sensor 85, although the wavelengths are different.

  In the second embodiment described above, when the multilayer interference filter is used, the optical characteristics of the optical filters 76a to 76i may change depending on the incident angle of the light beam. Therefore, it is desirable that the light beam R2 ′ from the diffusing surface 16 enters each of the optical filters 76a to 76i. For this purpose, the diffusing surface 16 of the light diffusing element 15 is preferably on the focal plane of the collimator lens 72, and the principal ray of the light beam R2 ′ from the diffusing surface 16 is preferably parallel to the optical axis Ax2. That is, it is desirable that the optical system including the imaging optical system 10 and the light diffusing element 15 is configured to be telecentric.

  However, when the imaging optical system 10 is used as a camera lens, the image side of the imaging optical system 10 is often not telecentric as described in the first embodiment. In such a case, similarly to the first embodiment, the field lens 18 may be arranged near the image side (or object side) of the light diffusing element 15 so as to be telecentric.

  In the first and second embodiments described above, a part of the imaging optical system 10 may be a focusing lens group. Further, the imaging optical system 10 may be a single focal lens having a fixed focal length or a zoom lens having a variable focal length.

  Next, a third embodiment of the imaging device will be described with reference to FIG. An imaging apparatus (multi-imaging camera) 101 according to the third embodiment includes an imaging optical system 110, a light diffusing element 15, a detection unit 20, and an image processing unit 40. In the third embodiment, the light diffusing element 15, the detection unit 20, and the image processing unit 40 have the same configurations as those in the first embodiment. Description is omitted.

  The imaging optical system 110 includes an objective lens 111, a lens 112, an imaging lens 113, and a diaphragm 114. The imaging optical system 110 is an optical system used as a microscope, and forms an enlarged intermediate image Im2 (real image) of the minute object OB2 by transmitting light from the minute object OB2. Although the objective lens 111, the lens 112, and the imaging lens 113 are schematically depicted as single lenses in FIG. 10, they may be composed of a plurality of lenses.

  The objective lens 111 transmits the light from the minute object OB2 and forms an enlarged real image I1 of the minute object OB2. The lens 112 transmits the light from the objective lens 111 and guides it to the imaging lens 113. The imaging lens 113 transmits the light from the lens 112 and forms an intermediate image Im2 of the minute object OB2. The diaphragm 114 is formed in a disk shape having an opening 114a in the center, and is disposed in the vicinity of the object side of the imaging lens 113.

  The objective lens 111 of the imaging optical system 110 is the microscope objective lens 501 (see FIG. 12), the lens 112 of the imaging optical system 110 is the eyepiece lens 502 of the microscope (see FIG. 12), and imaging optics is used. Consider the position of the stop 114 of the system 110 as the eye point plane E (see FIG. 12) of the microscope. This is equivalent to observing the virtual image I2 described above through the imaging lens 113.

  Similarly to the first embodiment, the light diffusing element 15 is provided on the image side of the imaging optical system 110 (imaging lens 113), and the detection unit 20 is provided on the image side of the light diffusing element 15.

  In the imaging apparatus 101 of the third embodiment, the light beam R3 from the minute object OB2 passes through the objective lens 111, the lens 112, and the imaging lens 113 of the imaging optical system 110 and is on the diffusion surface 16 of the light diffusing element 15. And an intermediate image Im2 (real image) of the minute object OB2 is formed on the diffusion surface 16 of the light diffusing element 15. At this time, the spread angle of the light beam R3 from the minute object OB2 is limited by the opening 114a of the stop 114. Further, since the light beam R3 from the minute object OB2 is diffused and emitted on the diffusion surface 16 of the light diffusing element 15 where the intermediate image Im2 of the minute object OB2 is formed, the minute object OB2 exists on the diffusion surface 16. Is equivalent to that. Thereby, similarly to the first embodiment, the intermediate image Im2 of the minute object OB2 formed on the diffusion surface 16 of the light diffusing element 15 can be detected by the detection unit 20.

  The diffused light beam R3 ′ from the diffusing surface 16 is transmitted through the collimator lens 22 of the collimator optical system 21, and becomes a substantially parallel light beam whose principal ray is bent to the optical axis Ax3 side. The light beam R3 ′ from the diffusing surface 16 that has become a substantially parallel light beam by the collimator lens 22 passes through one of the first optical filter 26a to the ninth optical filter 26i in the optical filter array 25. The light beam R 3 ′ from the diffusion surface 16 that has passed through the optical filter array 25 passes through the condenser lens 23 of the collimator optical system 21 and is condensed on the lens array 30, and any of the plurality of microlenses 31 in the lens array 30. The light passes through the light and enters the detection surface 36 of the image sensor 35.

  Similar to the first embodiment, images of the plurality of optical filter arrays 25 by the plurality of microlenses 31 are formed on the detection surface 36 of the image sensor 35. The image sensor 35 detects images of a plurality of optical filter arrays 25 formed on the detection surface 36 (that is, images of a plurality of sets of optical filters 26 a to 26 i), and outputs detection signals to the image processing unit 40. Similar to the first embodiment, the image processing unit 40 generates a multi-wavelength band image of the object OB1 based on the detection signal output from the image sensor 35. In this manner, a multi-wavelength band image of the minute object OB2 corresponding to each wavelength characteristic of the first optical filter 26a to the ninth optical filter 26i is captured and acquired. Note that the multi-wavelength band image of the minute object OB2 generated by the image processing unit 40 is observed using an image display device (not shown) or the like.

  Thus, according to the third embodiment, the same effect as that of the first embodiment can be obtained. In particular, even when an enlarged image of the minute object OB2 is detected, a highly accurate multi-wavelength band image can be obtained.

  In the third embodiment, as in the first embodiment, it is desirable that the optical system including the imaging optical system 110 and the light diffusing element 15 is configured to be telecentric. However, when the imaging optical system 110 is not telecentric, the field lens 18 is arranged near the image side (or object side) of the light diffusing element 15 so as to be telecentric, as in the first and second embodiments. It may be.

  In the third embodiment described above, instead of the detection unit 20 and the image processing unit 40 having the same configuration as in the first embodiment, the detection unit 70 and the image processing unit 90 having the same configuration as in the second embodiment may be used. Is possible.

  In the first to third embodiments described above, the light distribution characteristics of the light diffused by the light diffusing element 15 are likely to be bright at the central portion and dark at the peripheral portion, as shown in FIG. In such a case, even if the optical characteristics of the nine optical filters of the optical filter arrays 25 and 75 are the same, the incident light amounts of the nine imaging light beams with respect to the image sensors 35 and 85 are different from each other. Therefore, when the image processing units 40 and 90 generate a multi-wavelength band image, image correction according to the light distribution characteristics of the light diffused by the light diffusing element 15 may be performed.

  In the first to third embodiments described above, a bandpass filter is used as the optical filter of the optical filter arrays 25 and 75. However, as a transmission wavelength band, an ultraviolet region, a visible region, an infrared region, or the like is desired. Can be set to the wavelength band.

  In the first to third embodiments described above, bandpass filters are used as the optical filters of the optical filter arrays 25 and 75. However, the present invention is not limited to this. As the optical filter of the optical filter array, for example, various optical filters such as a filter having an arbitrary spectral transmittance, a polarizing filter, a wave plate, an ND filter, and a combination thereof can be used. Further, the number of optical filters in the optical filter array is not limited to nine, and a plurality of optical filters may be provided.

  In the first to third embodiments described above, the light diffusing element 15 is configured using a diffusing lens array composed of a plurality of convex diffusing microlenses capable of diffusing light. However, it is not limited to this. For example, the diffusing microlens may be concave. Further, for example, the light diffusing element may be configured using a diffusion plate capable of diffusing light.

1 Imaging device (first embodiment)
DESCRIPTION OF SYMBOLS 10 Imaging optical system 15 Light diffusing element 20 Detection part 21 Collimator optical system 22 Collimator lens 23 Condensing lens 25 Optical filter array 26a 1st optical filter 26b 2nd optical filter 26c 3rd optical filter 26d 4th optical filter 26e 5th Optical filter 26f 6th optical filter 26g 7th optical filter 26h 8th optical filter 26i 9th optical filter 30 Lens array 31 Micro lens 35 Image sensor 36 Detection surface 40 Image processing part 51 Imaging device (2nd Embodiment)
70 detector 71 collimator optical system 72 collimator lens 75 optical filter array 76a first optical filter 76b second optical filter 76c third optical filter 76d fourth optical filter 76e fifth optical filter 76f sixth optical filter 76g seventh optical filter 76h Eighth optical filter 76i Ninth optical filter 80 Lens array 81a First small lens 81b Second small lens 81c Third small lens 81d Fourth small lens 81e Fifth small lens 81f Sixth small lens 81g Seventh small lens 81h Eighth Small lens 81i Ninth small lens 85 Image sensor 86 Detection surface 90 Image processing unit 101 Imaging device (third embodiment)
110 Imaging optical system

Claims (6)

An imaging optical system that transmits light from the object and forms an intermediate image of the object;
A collimator optical system that makes light from the imaging optical system substantially parallel light;
An optical element array comprising a plurality of optical elements arranged two-dimensionally along a plane perpendicular to the optical axis, and allowing the plurality of optical elements to pass light that has become substantially parallel light by the collimator optical system;
A lens array that refracts light that has passed through the collimator optical system and the optical element array;
An image sensor arranged on a plane conjugate with the optical element array by the lens array or on a plane conjugate with the intermediate image of the imaging optical system, and detecting light from the lens array;
An image processing unit for obtaining information on the object according to the optical characteristics of the optical element based on the detection signal output from the image sensor;
An imaging apparatus comprising: a light diffusing element that diffuses light from the imaging optical system toward the collimator optical system on an image plane of the imaging optical system. The collimator optical system is provided between the imaging optical system and the optical element array, and collimator lenses that make light from the imaging optical system substantially parallel light; the optical element array; and the lens array; A condenser lens that transmits light from the optical element array and forms an image of the object,
The lens array is composed of a plurality of microlenses having a positive refractive power arranged two-dimensionally along a plane perpendicular to the optical axis, and is disposed on the image plane of the condenser lens. The light from the optical lens is transmitted through the plurality of microlenses,
The image sensor is disposed on a plane conjugate with the optical element array by the lens array, and detects images of the plurality of optical element arrays formed by the plurality of microlenses. The imaging device according to claim 1. The lens array includes a plurality of small lenses having positive refractive power arranged two-dimensionally along a plane perpendicular to the optical axis, and each of the light from the plurality of optical elements in the optical element array Transmit through multiple small lenses,
The image sensor is disposed on a focal plane of the plurality of small lenses conjugate with an image plane of the imaging optical system, and detects the images of the plurality of objects formed by the plurality of small lenses. The imaging apparatus according to claim 1.   The imaging apparatus according to claim 1, wherein the imaging optical system forms an enlarged image of the object as the intermediate image.   5. The imaging apparatus according to claim 1, wherein an optical system including the imaging optical system and the light diffusing element is configured to be telecentric. 6.   6. The light diffusing element is configured using a diffusing lens array including a plurality of diffusing microlenses arranged two-dimensionally along a plane perpendicular to the optical axis. The imaging device according to any one of the above.