Lens device

Abstract

Provided are: an optical member comprising a plurality of aperture regions; a lens device; and an imaging device. A lens device (100) comprises: an imaging optical system (100A); a first polarization unit (101) which polarizes at least some light rays transmitted through the imaging optical system (100A); and a filter unit (130) which is disposed more on the image side than the first polarization unit (101) and disposed at a pupil position of the imaging optical system or in the vicinity of the pupil position, the filter unit (130) including a plurality of aperture regions including a first aperture region and a second region which transmit the light rays of the imaging optical system (100A), a plurality of wavelength selection filters which are disposed in the first aperture region and the second aperture region and transmit light, at least some of which has different wavelength bands, and a second polarization filter which is disposed in the first aperture region and the second aperture region and has a plurality of polarization filters with mutually different polarization directions.

Description

[Technical Field]

[0001] The present invention relates to an optical member, a lens device, and an imaging device, and more particularly to an optical member, a lens device, and an imaging device that are provided with a plurality of aperture regions. [Background technology]

[0002] 2. Description of the Related Art Techniques for simultaneously acquiring a plurality of images having different image information from each other are known.

[0003] Patent Document 1 describes a technology for simultaneously obtaining multiple images under different optical conditions. The technology described in Patent Document 1 performs crosstalk correction processing to reduce the effects of crosstalk caused by arrayed optical elements such as microlens arrays and lenticular lenses. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-211430 Summary of the Invention

[0005] One embodiment of the technique of the present disclosure provides an optical member, a lens device, and an imaging device that include a plurality of aperture regions. [Means for solving the problem]

[0006] A lens device according to one aspect of the present invention comprises an imaging optical system, a first polarization section that polarizes at least a portion of the light rays that pass through the imaging optical system, and a filter unit that is arranged closer to the image side than the first polarization section and is arranged at or near the pupil position of the imaging optical system, the filter unit including a plurality of aperture regions including a first aperture region and a second aperture region that transmit the light rays of the imaging optical system, a plurality of wavelength-selective filters that are arranged in the first aperture region and the second aperture region and that transmit light having at least a portion of different wavelength bands, and a second polarizing filter that is arranged in the first aperture region and the second aperture region and has a plurality of polarizing filters whose polarization directions are different from each other.

[0007] Preferably, the first polarizing unit has a variable polarization direction.

[0008] Preferably, the first polarizing unit is a first polarizing filter that rotates around its optical axis.

[0009] Preferably, the first polarization unit is arranged on the object side of a lens included in the imaging optical system.

[0010] Preferably, the first polarization section is disposed within the imaging optical system and is disposed closer to the object side than the filter unit.

[0011] Preferably, the first polarizing section has a plurality of regions whose polarization directions are different from one another.

[0012] Preferably, the first polarizing unit has a plurality of regions whose polarization directions are independently changeable, and the plurality of regions rotate along their respective rotation axes.

[0013] Preferably, the second polarizing filter is disposed on the image side of the plurality of wavelength selective filters.

[0014] Preferably, the filter unit further includes a plurality of optical path length compensation filters disposed in the first and second aperture regions and compensating for axial chromatic aberration caused by the plurality of wavelength selection filters.

[0015] Preferably, the filter unit further includes an ND filter disposed in the first opening region and the second opening region, for reducing the amount of light in the imaging optical system.

[0016] Preferably, the first polarizing section is composed of a polarizing filter and a liquid crystal polarization rotator element disposed on the image side of the polarizing filter.

[0017] Preferably, the lens device includes a polarization direction control unit that controls the polarization direction of the first polarization unit, and the polarization direction control unit controls the polarization direction of the first polarization unit based on the ratio between the amount of light corresponding to the first opening area and the amount of light corresponding to the second opening area.

[0018] Preferably, the lens device includes a polarization direction control unit that controls the polarization direction of the first polarization unit at a predetermined position, and the polarization direction control unit controls the polarization direction of the first polarization unit based on the ratio between the amount of light corresponding to the first opening area and the amount of light corresponding to the second opening area.

[0019] Another aspect of the optical element of the present invention is an optical element that is arranged at or near the pupil position of an imaging optical system, and includes: a first polarizing filter that polarizes at least a portion of the light rays that pass through the imaging optical system; a plurality of aperture regions including a first aperture region and a second aperture region that transmit the light rays of the imaging optical system, and a plurality of wavelength-selective filters that are arranged in the first aperture region and the second aperture region and transmit light of at least a portion of different wavelength bands; and a second polarizing filter that is arranged in the first aperture region and the second aperture region and has a plurality of polarizing filters with mutually different polarization directions, wherein the first polarizing filter is arranged closest to the object side, and the second polarizing filter is arranged closest to the image side.

[0020] An imaging device according to another aspect of the present invention includes the lens device or the optical member described above.

[0021] Another aspect of the optical element of the present invention is an optical element that is arranged at or near the pupil position of an imaging optical system, and has a plurality of aperture regions including a first aperture region and a second aperture region that transmit light rays of the imaging optical system, and is equipped with: an ND filter that is arranged in the first aperture region and the second aperture region and reduces the amount of light rays of the imaging optical system; a plurality of wavelength selection filters that are arranged in the first aperture region and the second aperture region and transmit light having at least some wavelength bands that differ from each other; a plurality of optical path length correction filters that are arranged in the first aperture region and the second aperture region and correct axial chromatic aberration caused by the plurality of wavelength selection filters; and a plurality of polarizing filters that are arranged in the first aperture region and the second aperture region and have mutually different polarization directions, and the optical path length correction filter is arranged on the image side of the wavelength selection filter.

[0022] An imaging device according to another aspect of the present invention is an imaging device including the optical member described above, and further including a polarizing section that polarizes at least a portion of light rays that pass through the imaging optical system. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of an imaging device. [Figure 2] FIG. 2 is a diagram showing the configuration of the signal processing unit and the lighting device. [Figure 3] FIG. 3 is a diagram showing a schematic configuration of an imaging element. [Figure 4] FIG. 4 is a cross-sectional view showing a schematic configuration of one pixel shown in FIG. [Figure 5] FIG. 5 is a perspective view of the appearance of the lens device. [Figure 6] FIG. 6 is a cross-sectional view of the lens device taken along the yz plane. [Figure 7] FIG. 7 is an external view of the frame. [Figure 8] FIG. 8 is a diagram showing an example of the configuration of a wavelength polarization filter unit. [Figure 9] FIG. 9 is a diagram illustrating an example of the configuration of a filter set. [Figure 10]FIG. 10 is a diagram showing the relationship between the aperture area and the filter configuration. [Figure 11] FIG. 11 is a diagram showing the frame and the filter set. [Figure 12] FIG. 12 is a conceptual diagram showing the first polarizing filter and the lens device. [Figure 13] FIG. 13 is a table illustrating the adjustment of the light amount. [Figure 14] FIG. 14 is a table illustrating the adjustment of the light amount. [Figure 15] FIG. 15 is a table for explaining the adjustment of the light amount. [Figure 16] FIG. 16 is a conceptual diagram showing the first polarizing filter and the lens device. [Figure 17] FIG. 17 is a table for explaining the adjustment of the light amount. [Figure 18] FIG. 18 is a table for explaining the adjustment of the light amount. [Figure 19] FIG. 19 is a table for explaining the adjustment of the light amount. [Figure 20] FIG. 20 is a conceptual diagram of the first polarizing filter. [Figure 21] FIG. 21 is a table for explaining the adjustment of the light amount. [Figure 22] FIG. 22 is a diagram illustrating another example of the first polarization section. [Figure 23] FIG. 23 is a diagram illustrating another example of the first polarization section. [Figure 24] FIG. 24 is a conceptual diagram showing the first polarizing filter and the wavelength polarizing filter unit. [Figure 25] FIG. 25 is a conceptual diagram showing the first polarizing filter and the wavelength polarizing filter unit. [Figure 26] FIG. 26 is a diagram illustrating the arrangement of the second polarizing filter. [Figure 27] FIG. 27 is a diagram illustrating the arrangement of the second polarizing filter. [Figure 28] FIG. 28 is a diagram illustrating the arrangement of the wavelength-selective filter and the second polarizing filter. [Figure 29] FIG. 29 is a diagram illustrating the arrangement of the wavelength-selective filter and the second polarizing filter. [Figure 30] FIG. 30 is a diagram illustrating the arrangement of the ND filter and the wavelength selection filter. [Figure 31] FIG. 31 is a diagram illustrating the arrangement of the ND filters. [Figure 32] FIG. 32 is a diagram illustrating the arrangement of the ND filters. [Figure 33] FIG. 33 is a diagram illustrating the arrangement of the optical path length correction filter. [Figure 34] FIG. 34 is a diagram illustrating the arrangement of the optical path length correction filter. DETAILED DESCRIPTION OF THE INVENTION

[0024] Preferred embodiments of an optical member, a lens device, and an imaging device according to the present invention will now be described with reference to the accompanying drawings.

[0025] FIG. 1 is a diagram showing a schematic configuration of an imaging device 10. The imaging device 10 is a multispectral camera that captures multispectral images. The imaging device 10 includes a lens device 100, an imaging device main body 200, and an illumination device 100B. The imaging device main body 200 includes an image sensor 210 and a signal processing unit 230. The lens device 100 includes a first polarizing filter 101 (first polarizing unit) disposed on the object side, an imaging optical system 100A configured with a first lens 110 and a second lens 120, and a wavelength polarization filter unit (filter unit, optical member) 130 disposed at or near the pupil position of the imaging optical system 100A. The imaging device 10 also includes an illumination device 100B. The imaging device 10 acquires a multispectral image of a subject illuminated by the illumination device 100B. In the following description, the object side is the positive side of the z axis shown in the figure, and the image side is the negative side of the z axis.

[0026] 2 is a diagram showing the configurations of the signal processing unit 230 and the lighting device 100B. The signal processing unit 230 includes an analog signal processing unit 232 that performs analog signal processing on the signal output from the image sensor 210, an image generation unit 234, and a coefficient storage unit 236. The image generation unit 234 (processor) includes a non-transitory recording medium (not shown) such as a read-only memory (ROM) that stores computer-readable code of an imaging program to be executed by a computer, and a temporary working storage area (not shown). The image generation unit 234 generates multiple images (spectral images) corresponding to the wavelength bands of multiple wavelength-selective filters arranged in the imaging optical system 100A based on multiple image signals output from the image sensor 210. The image generation unit 234 can generate, for example, images in wavelength bands λ1, λ2, and λ3 corresponding to the wavelength-selective filters (three-band multispectral images).

[0027] The functions of the signal processing unit 230 described above can be realized using various processors and recording media. The various processors include, for example, a CPU (Central Processing Unit), which is a general-purpose processor that executes software (programs) to realize various functions, a GPU (Graphics Processing Unit), which is a processor specialized for image processing, and a programmable logic device (PLD), such as an FPGA (Field Programmable Gate Array), whose circuit configuration can be changed after manufacturing. Each function may be realized by a single processor, or by multiple processors of the same or different types (e.g., multiple FPGAs, a combination of a CPU and an FPGA, or a combination of a CPU and a GPU). Furthermore, multiple functions may be realized by a single processor. The hardware structure of these various processors is, more specifically, an electric circuit formed by combining circuit elements such as semiconductor elements.

[0028] When the above-mentioned processor or electrical circuit executes software (program), the code readable by the computer (for example, various processors and electrical circuits constituting the image generation unit 234, and / or a combination thereof) of the software to be executed is stored in a non-transitory recording medium such as a ROM, and the computer references the software.

[0029] When the imaging device 10 receives a shooting instruction input from a shutter release switch (not shown) or the like, it performs exposure control on the imaging element 210. An optical image of the subject formed on the light receiving surface of the imaging element 210 by this exposure control is converted into an electrical signal by the imaging element 210. Charges corresponding to the amount of light incident on the photodiode 212 (FIG. 3) are accumulated in each pixel of the imaging element 210, and electrical signals corresponding to the amount of charge accumulated in each pixel are read out and output from the imaging element 210 as image signals.

[0030] The illumination device 100B includes a light source 320 that irradiates an object with illumination light having spectral characteristics (wavelength bands, etc.) including the wavelength bands (wavelength bands λ1, λ2, λ3) of the plurality of wavelength selection filters arranged in the imaging optical system 100A described above, and a light source control unit 310 that controls the irradiation of the illumination light by the light source 320. Various light sources 320 are used as the light source 320 of the illumination device 100B. For example, a halogen lamp or an LED (light emitting diode) is used as the light source 320.

[0031] Fig. 3 is a diagram showing a schematic configuration of the image sensor 210, and Fig. 4 is a cross-sectional view showing a schematic configuration of one pixel shown in Fig. 3. The image sensor 210 is a CMOS (Complementary Metal-Oxide Semiconductor) type image sensor (image sensor), and is a monochrome image sensor having a pixel array layer 211, a polarization filter element array layer 213, and a microlens array layer 215. The layers are arranged in this order from the image (plane) side to the object side: pixel array layer 211, polarization filter element array layer 213 (plurality of polarization elements), and microlens array layer 215. Note that the image sensor 210 is not limited to a CMOS type, and may also be an XY address type or a CCD (Charge Coupled Device) type image sensor.

[0032] The pixel array layer 211 is configured by arranging a large number of photodiodes 212 (multiple pixel groups) two-dimensionally. One photodiode 212 constitutes one pixel. The photodiodes 212 are regularly arranged along the horizontal direction (x direction) and vertical direction (y direction).

[0033] The polarization filter element array layer 213 is configured by two-dimensionally arranging four types of polarization filter elements (polarizers) 214A, 214B, 214C, and 214D (multiple polarization elements) with different polarization directions (polarization directions of transmitted light). The polarization directions of the polarization filter elements 214A, 214B, 214C, and 214D can be, for example, 0°, 45°, 90°, and 135°. As another example, the polarization directions of the polarization filter elements 214A, 214B, 214C, and 214D can be 0°, 60°, 90°, and 120°. These polarization directions can correspond to the polarization directions of the second polarization filters 148A to 148C (see FIG. 8) in the wavelength polarization filter unit 130. The image sensor 210 includes multiple pixels that selectively receive any of the light transmitted through the multiple aperture areas using the polarization filter elements 214A to 214D. These polarizing filter elements 214A to 214D are arranged at the same intervals as the photodiodes 212, and are provided for each pixel.

[0034] The microlens array layer 215 includes microlenses 216 arranged for each pixel.

[0035] Fig. 5 is an external perspective view of lens device 100, and Fig. 6 is a cross-sectional view of lens device 100 in the yz plane. As shown in these figures, lens device 100 has a single imaging optical system 100A configured from a first lens 110 and a second lens 120 disposed in a lens barrel 102. First lens 110 and second lens 120 may be a lens group configured from multiple lenses. Furthermore, a slit 108 is formed in lens barrel 102 at the pupil position (near the pupil) of lens device 100, and a wavelength polarization filter unit 130 is inserted into this slit 108 and is disposed with its optical axis aligned with optical axis L of imaging optical system 100A.

[0036] FIG. 7 is an external view of the frame 132, and FIG. 8 is a diagram showing an example of the configuration of the wavelength polarization filter unit 130. Parts (a) to (f) of FIG. 7 are a back view, a top view, a left side view, a bottom view, a perspective view, and a front view, respectively. As shown in parts (a), (e), and (f) of FIG. 7, the frame 132 has four opening regions 132A to 132D. The opening regions 132A to 132D correspond to the first to fourth opening regions. The shapes of the opening regions 132A to 132D are not limited to sector shapes, and may be other shapes such as circles, strips, rectangles, polygons, etc. When acquiring three images (images in wavelength bands λ1, λ2, and λ3), three opening regions are sufficient, and therefore opening region 132D is shielded by a shielding member B as shown in FIG. 8. Furthermore, in this example, aperture regions 132A to 132C are made effective by blocking light from aperture region 132D with shielding member B, but this is not limiting. For example, aperture region 132D may be provided with a wavelength selection filter of the same wavelength band as any one of aperture regions 132A to 132C and a second polarization filter of the same polarization direction.

[0037] As shown in FIG. 8, filter sets 140A to 140C (ND (Neutral Density) filter, wavelength selection filter, optical path length compensation filter, and second polarization filter) are arranged in the three open areas (132A to 132C) that are not light-shielded. Note that FIG. 8 shows a case where each of the filter sets 140A to 140C is composed of four filters. Furthermore, in each of the filter sets 140A to 140C, the filter closest to the object (ND filter) is provided on the object-side surface of the frame 132, and the remaining three filters (wavelength selection filter, optical path length compensation filter, and second polarization filter) are provided on the image-side surface of the frame 132. Note that the arrangement of the filters and the position of the frame 132 arranged between the filters are not limited to the above example, and various embodiments can be adopted.

[0038] FIG. 9 is a diagram illustrating an example of the configuration of the filter sets 140A to 140C.

[0039] Filter set 140A is composed of four different types of filters. Filter set 140A is composed, in order from the object side, of an ND filter 142A, a wavelength-selective filter 144A that transmits wavelength band λ1, an optical path length compensation filter 146A, and a second polarizing filter 148A with a polarization direction of 0°. Similarly, filter set 140B is composed, in order from the object side, of an ND filter 142B, a wavelength-selective filter 144B that transmits wavelength band λ2, an optical path length compensation filter 146B, and a second polarizing filter 148B with a polarization direction of 60°. Similarly, filter set 140C is composed, in order from the object side, of an ND filter 142C, a wavelength-selective filter 144C that transmits wavelength band λ3, an optical path length compensation filter 146C, and a second polarizing filter 148C with a polarization direction of 120°. In this example, three spectral images, one in wavelength band λ1, one in wavelength band λ2, and one in wavelength band λ3, are acquired, and therefore the polarization directions of the second polarizing filters 148A-148C are different from one another. For example, when acquiring two spectral images, second polarizing filters with at least two different polarization directions are used. λ1, λ2, and λ3 have some different wavelength bands. The ND filters 142A-142C have the function of reducing the amount of light, and the optical path length correction filters 146A-146C have the function of correcting axial chromatic aberration. While this example shows the polarization directions at 0°, 60°, and 120°, other angle combinations are also possible.

[0040] FIG. 10 is a diagram showing the relationship between the aperture area and the filter configuration.

[0041] Wavelength polarization filter unit 130 has aperture regions 132A to 132D formed by frame 132. Specifically, region boundary members 132(α) of frame 132 are arranged at the boundaries between aperture region 132A and aperture region 132D and between aperture region 132B and aperture region 132C, and region boundary members 132(β) are arranged at the boundaries between aperture region 132A and aperture region 132B and between aperture region 132C and aperture region 132D. ND filters 142A to 142C, wavelength selection filters 144A to 144C, optical path length correction filters 146A to 146C, and second polarization filters 148A to 148C are arranged in each of aperture regions 132A to 132C.

[0042] Fig. 11 is a diagram showing frame 132 and filter sets 140A to 140C. Fig. 11(A) is a diagram showing opening regions 132A to 132D formed in frame 132, and Fig. 11(B) is a diagram showing cross sections of filter sets 140B and 140C arranged in opening region 132B and opening region 132C.

[0043] The aperture region 132B is provided with an ND filter 142B, a wavelength selection filter 144B, an optical path length correction filter 146B, and a second polarization filter 148B. The aperture region 132C is provided with an ND filter 142C, a wavelength selection filter 144C, an optical path length correction filter 146C, and a second polarization filter 148C.

[0044] <Adjusting light intensity with a polarizing filter> As described above, the imaging device 10 of the present disclosure includes the first polarizing filter 101 and the second polarizing filters 148A to 148C. The imaging device 10 can adjust the amount of light in the opening regions 132A to 132C by using a difference in the polarization direction between the first polarizing filter 101 and the second polarizing filters 148A to 148C.

[0045] First to fourth embodiments relating to the light amount adjustment of the opening areas 132A to 132C in the imaging device 10 will be described below.

[0046] First Embodiment First, a description will be given of the first embodiment. In this embodiment, the first polarizing section is made up of a first polarizing filter 101, and the amount of light in the opening regions 132A to 132C is adjusted by rotating the first polarizing filter 101.

[0047] 12 is a conceptual diagram of the first polarizing filter 101 and lens device 100 of this embodiment. Note that the illustration does not include the frame 132 of the wavelength polarizing filter unit 130. Furthermore, the ND filters 142A to 142C, wavelength selection filters 144A to 144C, and optical path length correction filters 146A to 146C are illustrated as a single intermediate filter A.

[0048] The first polarizing filter 101 transmits light polarized in one direction. The first polarizing filter 101 functions as a first polarizing unit and polarizes at least a portion of the light passing through the imaging optical system 100A. The first polarizing filter 101 rotates around the optical axis L, changing the polarization direction of the light it transmits. When the rotation angle θ of the first polarizing filter 101 is 0°, the polarization direction is also 0°, and the first polarizing filter 101 is arranged so that the polarization direction can be changed to match the rotation angle θ. Note that the polarization direction of 0° is along the y-axis direction. Furthermore, when viewing the first polarizing filter 101 from the object side to the image side, a clockwise rotation is considered a positive rotation angle, and a counterclockwise rotation is considered a negative rotation angle.

[0049] The light amount (or change in light amount) of the opening regions 132A to 132C can be calculated from the rotation angle θ of the first polarizing filter 101.

[0050] Specifically, the light intensity change α of each of the opening regions 132A to 132C is calculated by the following formula (1): i The change in the amount of light in the opening region 132A is indicated by a change in amount of light α0, the change in the amount of light in the opening region 132B is indicated by a change in amount of light α1, and the change in the amount of light in the opening region 132C is indicated by a change in amount of light α2.

[0051]

number

[0052] In addition, θ in the formula (1) represents the angle of the polarization direction of the first polarizing filter 101 (or the rotation angle of the first polarizing filter 101). i In the figure, Φ0 indicates the angle of the polarization direction of the second polarizing filter in aperture region 132A, Φ1 indicates the angle of the polarization direction of the second polarizing filter in aperture region 132B, and Φ2 indicates the angle of the polarization direction of the second polarizing filter in aperture region 132C.

[0053] As described above, the amount of light in the opening regions 132A to 132C can be adjusted by the first polarizing filter 101 and the second polarizing filters 148A to 148C.

[0054] An example of adjusting the light intensity of the opening regions 132A to 132C will be described below.

[0055] (First Example) Table 501 in FIG. 13 is a table for explaining adjustment of the light intensity in the first embodiment. Note that this example does not use the ND filter 142. Furthermore, the wavelength-selective filter 144A arranged in the aperture region 132A selectively transmits light in the blue wavelength band (denoted as "B" in the table), the wavelength-selective filter 144B arranged in the aperture region 132B selectively transmits light in the green wavelength band (denoted as "G" in the table), and the wavelength-selective filter 144C arranged in the aperture region 132C selectively transmits light in the red wavelength band. Furthermore, in this example and the examples described below, the polarization direction of the second polarizing filter 148A arranged in the aperture region 132A is 0°, the polarization direction of the second polarizing filter 148B arranged in the aperture region 132B is 60°, and the polarization direction of the second polarizing filter 148C arranged in the aperture region 132C is 120°.

[0056] When light source 320 is a halogen, rotating first polarizing filter 101 clockwise by 4 degrees brings the ratio of the light amounts in opening regions 132A to 132C closer to 1:1:1, improving the balance of the light amounts in each opening region. This is explained below using Table 501.

[0057] When the light source 320 is a halogen light source and the first polarizing filter 101 is not provided (initial state), the light intensity obtained in the opening region 132A ("B") is 40, the light intensity obtained in the opening region 132B ("G") is 100, and the light intensity obtained in the opening region 132C ("R") is 140 (item (1) in Table 501). When the first polarizing filter 101 is rotated clockwise by 4°, the change in the light intensity in each of the opening regions 132A to 132C is calculated using the above-mentioned formula (1) (item (2) in Table 501). Furthermore, by calculating the product of the light intensity in the initial state when the light source 320 is a halogen light source and the calculated change in light intensity, the light intensity in the opening regions 132A to 132C when the first polarizing filter 101 is rotated clockwise by 4° is calculated (item (3) in Table 501). The ratio of these light intensities is 1.27297:1:0.860377 (item (4) in Table 501), and by rotating the first polarizing filter 101 clockwise by 4 degrees, the light intensities of the aperture regions 132A to 132C can be well balanced.

[0058] When light source 320 is an LED, rotating first polarizing filter 101 counterclockwise by 63° brings the ratio of the amount of light in opening areas 132A to 132C closer to 1:1:1, improving the balance of the amount of light in each opening area. This is explained below using Table 501.

[0059] When the light source 320 is an LED, and the first polarizing filter 101 is not provided (initial state), the light intensity obtained in the opening region 132A ("B") is 140, the light intensity obtained in the opening region 132B ("G") is 100, and the light intensity obtained in the opening region 132C ("R") is 30 (item (5) in Table 501). When the first polarizing filter 101 is rotated 63° counterclockwise, the change in the light intensity in each of the opening regions 132A to 132C is calculated using the above-mentioned formula (1) (item (6) in Table 501). Furthermore, by calculating the product of the light intensity in the initial state when the light source 320 is an LED and the calculated change in light intensity, the light intensity in the opening regions 132A to 132C when the first polarizing filter 101 is rotated 63° counterclockwise is calculated (item (7) in Table 501). The ratio of these light intensities is 0.972756:1:1.008585 (item (8) in Table 501), and by rotating the first polarizing filter 101 counterclockwise by 63°, the light intensities of the aperture regions 132A to 132C can be well balanced.

[0060] As described above, by rotating the first polarizing filter 101 to a predetermined angle, the light intensity ratio of the opening areas 132A to 132C can be made close to 1:1:1, even when the light source 320 is a halogen or LED, and the light intensity of each opening area can be well balanced.

[0061] (Second Example) Next, a second embodiment will be described. Table 503 in Fig. 14 is a table for explaining adjustment of the light intensity in the second embodiment. In this embodiment, the light source 320 is changed from halogen to LED. The ND filters 142A to 142C are set when the light source 320 is halogen and the rotation angle θ of the first polarizing filter 101 is 0°. The other settings are the same as in the first embodiment.

[0062] When light source 320 is changed from halogen to LED, first polarizing filter 101 can be rotated clockwise by 121° to bring the light intensity ratio of aperture areas 132A to 132C closer to 1:1:1, improving the balance of the light intensity of each aperture area. This is explained below using Table 503.

[0063] In the initial state when the light source 320 is an LED and halogen (without the first polarizing filter 101 and without the ND filters 142A to 142C), the same amount of light as in the first embodiment is obtained in the opening regions 132A to 132C (items (1) and (2) in Table 503). When the rotation angle of the first polarizing filter 101 is 0°, the change in the amount of light in each of the opening regions 132A to 132C is calculated using the above-mentioned formula (1) (item (3) in Table 503). The change in the amount of light in the ND filters 142A to 142C is set to match the case when the light source 320 is halogen (item (4) in Table 503). That is, the amount of light in opening region 132A ("B") is 40×1×0.625=25, the amount of light in opening region 132B ("G") is 100×0.25×1=25, and the amount of light in opening region 132C ("R") is 140×0.25×0.714286 ≒ 25 (the product of items (2), (3), and (4) in Table 503). Thus, when light source 320 is halogen, the light amounts of opening regions 132A to 132C are well balanced.

[0064] On the other hand, if the light source 320 is changed from halogen to LED, the ND filters 142A to 142C are set for halogen, and the balance of the light amounts described above will be lost (item (5) in Table 503).

[0065] Therefore, the change in light intensity is changed by rotating the first polarizing filter 101 clockwise by 121° (item (6) in Table 503). In this way, by rotating the first polarizing filter 101 clockwise by 121°, the light intensity of the opening regions 132A to 132C changes (item (7) in Table 503). The ratio of the light intensities of the opening regions 132A to 132C becomes 0.987516:1:0.91142 (item (8) in Table 503), and it is possible to prevent the imbalance in the light intensity from occurring even if the light source 320 is changed to an LED.

[0066] As described above, when the ND filters 142A to 142C are set for halogen and the light source 320 is changed from halogen to LED, the first polarizing filter 101 is rotated to change the polarization direction and adjust the light intensity of the opening regions 132A to 132C. This makes it possible to prevent the light intensity of the opening regions 132A to 132C from being out of balance.

[0067] (Third Example) Next, a third embodiment will be described. Table 505 in Fig. 15 is a table for explaining adjustment of the light intensity in the third embodiment. In this embodiment, the light source 320 changes from an LED to a halogen. The ND filters 142A to 142C are set for the case where the light source 320 is an LED and the rotation angle θ of the first polarizing filter 101 is 120°. The other settings are the same as in the first embodiment.

[0068] When light source 320 is changed from LED to halogen, rotating first polarizing filter 101 clockwise by 1° can bring the light intensity ratio of opening areas 132A to 132C closer to 1:1:1, preventing the balance of the light intensity of each opening area from being lost. This is explained below using table 505.

[0069] In the initial state when the light source 320 is an LED and halogen (without the first polarizing filter 101 and without the ND filters 142A to 142C), the same amount of light as in the first embodiment is obtained in the opening regions 132A to 132C (items (1) and (2) in Table 505). When the rotation angle of the first polarizing filter 101 is 120°, the change in the amount of light in each of the opening regions 132A to 132C is calculated using the above-mentioned formula (1) (item (3) in Table 505). The change in the amount of light in the ND filters 142A to 142C is set to match the case when the light source 320 is an LED (item (4) in Table 505). That is, the amount of light in opening region 132A ("B") is 140 x 0.25 x 0.714286 ≒ 25, the amount of light in opening region 132B ("G") is 100 x 0.25 x 1 = 25, and the amount of light in opening region 132C ("R") is 30 x 0.25 x 0.714286 ≒ 25 (the product of items (2), (3), and (4) in Table 505). Thus, when light source 320 is an LED, the light amounts of opening regions 132A to 132C are well balanced.

[0070] On the other hand, if the light source 320 is changed from an LED to a halogen, the ND filters 142A to 142C are set for an LED, and the balance of the light amounts described above will be lost (item (5) in Table 505).

[0071] Therefore, the first polarizing filter 101 is rotated clockwise by 1° to change the change in light intensity (item (6) in Table 505). In this way, by rotating the first polarizing filter 101 clockwise by 1°, the light intensity of the opening regions 132A to 132C changes (item (7) in Table 505). The ratio of the light intensities of the opening regions 132A to 132C becomes 1.076765:1:1.033738 (item (8) in Table 505), and it is possible to prevent the balance of the light intensities from being lost even if the light source 320 is changed to a halogen light source.

[0072] As described above, when the ND filters 142A to 142C are set for LEDs and the light source 320 is changed from LED to halogen, the first polarizing filter 101 is rotated to change the polarization direction and adjust the light intensity of the opening regions 132A to 132C. This makes it possible to prevent the light intensity of the opening regions 132A to 132C from becoming unbalanced.

[0073] Second Embodiment Next, a second embodiment will be described. In this embodiment, the first polarizing unit is composed of a first polarizing filter 101 having a plurality of regions with different polarization directions. The first polarizing filter 101 rotates to adjust the amount of light in the opening regions 132A to 132C.

[0074] 16 is a conceptual diagram of the first polarizing filter 101 and lens device 100 of this embodiment. Note that the illustration does not include the frame 132 of the wavelength polarizing filter unit 130. Furthermore, the ND filters 142A to 142C, wavelength selection filters 144A to 144C, and optical path length correction filters 146A to 146C are illustrated as a single intermediate filter A.

[0075] First polarizing filter 101 has multiple regions with mutually different polarization directions. Specifically, first polarizing filter 101 has four regions 101A to 101D with mutually different polarization directions. When first polarizing filter 101 has a rotation angle θ of 0°, region 101A has a polarization direction angle of 150°, region 101B has a polarization direction angle of 172°, region 101C has a polarization direction angle of 53°, and region 101D has a polarization direction angle of 20°.

[0076] Change in light intensity α of opening areas 132A to 132C ican be calculated by the following formula (2). The change in light amount in opening region 132A is indicated by a change in light amount α0, the change in light amount in opening region 132B is indicated by a change in light amount α1, the change in light amount in opening region 132C is indicated by a change in light amount α2, and the change in light amount in opening region 132D is indicated by a change in light amount α3. In the example of imaging device 10 described above, opening region 132D is shielded from light by shielding member B.

[0077]

number

[0078] In addition, the following values ​​are shown in formula (2).

[0079] θ'=(θ+180)%90

[0080]

number

[0081] Note that the above is expressed as A%B, which represents the remainder when A is divided by B.

[0082] Rotation angle of the first polarizing filter: θ

[0083]

number

[0084]

number

[0085] As described above, the amount of light in the opening regions 132A to 132C can be adjusted by the first polarizing filter 101 and the second polarizing filters 148A to 148C.

[0086] An example of adjusting the light intensity of the opening regions 132A to 132C will be described below.

[0087] (Fourth Example) Table 507 in Fig. 17 is a table for explaining the adjustment of the light intensity in Example 4. Note that this example does not use the ND filter 142. Furthermore, the wavelength selection filters 144A to 144C and second polarization filters 148A to 148C arranged in each aperture region are the same as those in Example 1.

[0088] When light source 320 is a halogen, rotating first polarizing filter 101 counterclockwise by 10 degrees brings the ratio of the light amounts in opening regions 132A to 132C closer to 1:1:1, improving the balance of the light amounts in each opening region. This is explained below using Table 507.

[0089] When the light source 320 is a halogen light source and the first polarizing filter 101 is not provided (initial state), the light intensity obtained in the opening region 132A ("B") is 40, the light intensity obtained in the opening region 132B ("G") is 100, and the light intensity obtained in the opening region 132C ("R") is 140 (item (1) in Table 507). When the first polarizing filter 101 is rotated counterclockwise by 10 degrees, the change in the light intensity in each of the opening regions 132A to 132C is calculated using the above-mentioned formula (2) (item (2) in Table 507). Furthermore, by calculating the product of the light intensity in the initial state when the light source 320 is a halogen light source and the calculated change in light intensity, the light intensity in the opening regions 132A to 132C when the first polarizing filter 101 is rotated counterclockwise by 10 degrees is calculated (item (3) in Table 507). The ratio of these light intensities is 0.994268:1:1.0242 (item (4) in Table 507), and by rotating the first polarizing filter 101 counterclockwise by 10 degrees, the balance of the light intensities of the aperture regions 132A to 132C can be improved.

[0090] When light source 320 is an LED, rotating first polarizing filter 101 counterclockwise by 76° brings the light intensity ratio in opening regions 132A to 132C closer to 1:1:1, resulting in a good balance. This is explained below using table 507.

[0091] When the light source 320 is an LED, and the first polarizing filter 101 is not provided (initial state), the light intensity obtained in the opening region 132A ("B") is 140, the light intensity obtained in the opening region 132B ("G") is 100, and the light intensity obtained in the opening region 132C ("R") is 30 (item (5) in Table 507). When the first polarizing filter 101 is rotated counterclockwise by 76°, the change in the light intensity in each of the opening regions 132A to 132C is calculated using the above-mentioned formula (2) (item (6) in Table 507). Furthermore, by calculating the product of the light intensity in the initial state when the light source 320 is an LED and the calculated change in light intensity, the light intensity in the opening regions 132A to 132C when the first polarizing filter 101 is rotated counterclockwise by 76° is calculated (item (7) in Table 507). The ratio of these light intensities is 1.038306:1:0.984503 (item (8) in Table 507), and by rotating the first polarizing filter 101 counterclockwise by 76°, the light intensities of the aperture regions 132A to 132C can be well balanced.

[0092] As described above, by rotating the first polarizing filter 101 to a predetermined angle, even if the light source 320 is a halogen or LED, the ratio of the light amounts in the opening areas 132A to 132C can be made close to 1:1:1, and the balance of the light amounts in each opening area can be improved.

[0093] (Fifth Example) Next, a fifth embodiment will be described. Table 509 in Fig. 18 is a table for explaining the adjustment of the light intensity in the fifth embodiment. In this embodiment, the light source 320 is changed from halogen to LED. The ND filters 142A to 142C are set when the light source 320 is halogen and the rotation angle θ of the first polarizing filter 101 is -57°. The other settings are the same as those in the first embodiment.

[0094] When light source 320 is changed from halogen to LED, rotating first polarizing filter 101 counterclockwise by 57° can bring the light intensity ratio of opening areas 132A to 132C closer to 1:1:1, improving the balance of the light intensity of each opening area. This is explained below using Table 509.

[0095] In the initial state when the light source 320 is an LED and halogen (without the first polarizing filter 101 and without the ND filters 142A-142C), the same amount of light as in the first embodiment is obtained in the opening regions 132A-132C (items (1) and (2) in Table 509). When the rotation angle of the first polarizing filter 101 is 57° counterclockwise, the change in the amount of light in each of the opening regions 132A-132C is calculated using the above-mentioned formula (2) (item (3) in Table 503). The change in the amount of light in the ND filters 142A-142C is set to match the case when the light source 320 is halogen (item (4) in Table 509). That is, the amount of light in opening area 132A ("B") is 40 x 0.395742 x 1 ≒ 15.8296, the amount of light in opening area 132B ("G") is 100 x 0.250463 x 0.632017 ≒ 15.8296, and the amount of light in opening area 132C ("R") is 140 x 0.218296 x 0.517962 ≒ 15.8296 (the product of items (2), (3), and (4) in Table 509).

[0096] On the other hand, if the light source 320 is changed from halogen to LED, the ND filters 142A to 142C are set for halogen, and the above-mentioned balance of light intensity is lost (item (5) in Table 509).

[0097] Therefore, the change in light intensity is changed by rotating the first polarizing filter 101 counterclockwise by 169° (item (6) in Table 509). In this way, by rotating the first polarizing filter 101 counterclockwise by 169°, the light intensity of the opening regions 132A to 132C changes (item (7) in Table 509). The light intensity ratio of the opening regions 132A to 132C becomes 1.021719:1:1.028647, and it is possible to prevent the imbalance in the light intensity from occurring even if the light source 320 is changed to an LED.

[0098] As described above, when the ND filters 142A to 142C are set for halogen and the light source 320 is changed from halogen to LED, the first polarizing filter 101 is rotated to change the polarization direction and adjust the light intensity of the opening regions 132A to 132C. This makes it possible to prevent the light intensity of the opening regions 132A to 132C from becoming unbalanced.

[0099] (Sixth Example) Next, a sixth embodiment will be described. Table 511 in Fig. 19 is a table for explaining the adjustment of the light intensity in the sixth embodiment. In this embodiment, the light source 320 changes from an LED to a halogen, and the ND filters 142A to 142C are set for the case where the light source 320 is an LED and the first polarizing filter 101 is rotated 11° counterclockwise. The other settings are the same as those in the first embodiment.

[0100] When light source 320 is changed from halogen to LED, first polarizing filter 101 can be rotated counterclockwise by 132° to bring the light intensity ratio of opening areas 132A to 132C closer to 1:1:1, preventing the balance of the light intensity of each opening area from being lost. This will be explained below using Table 511.

[0101] In the initial state when the light source 320 is an LED and halogen (without the first polarizing filter 101 and without the ND filters 142A to 142C), the same amount of light as in the first embodiment is obtained in the opening regions 132A to 132C (items (1) and (2) in Table 511). When the first polarizing filter 101 is rotated counterclockwise to a position of 11°, the change in the amount of light in each of the opening regions 132A to 132C is calculated using the above-mentioned formula (2) (item (3) in Table 511). The change in the amount of light in the ND filters 142A to 142C is set to match the case when the light source 320 is an LED (item (4) in Table 511). That is, the amount of light in aperture region 132A ("B") is 140×0.147053×1 ≒ 20.587, the amount of light in aperture region 132B ("G") is 100×0.89386×0.23032 = 20.587, and the amount of light in aperture region 132C ("R") is 30×0.982663×0.698353 ≒ 20.587 (the product of items (2), (3), and (4) in Table 511). Thus, when light source 320 is an LED, the light amounts of aperture regions 132A to 132C are well balanced.

[0102] On the other hand, if the light source 320 is changed from an LED to a halogen, the ND filters 142A to 142C are set for an LED, and the balance of the light amounts described above will be lost (item (5) in Table 511).

[0103] Therefore, the first polarizing filter 101 is rotated counterclockwise by 132° to change the change in light intensity (item (6) in Table 511). In this way, by rotating the first polarizing filter 101 clockwise by 132°, the light intensity of the opening regions 132A to 132C changes (item (7) in Table 511). The ratio of the light intensities of the opening regions 132A to 132C is 1.046081:1:1.001267, which makes it possible to prevent imbalance in the light intensity even when the light source 320 is changed to an LED.

[0104] As described above, when the ND filters 142A to 142C are set for LEDs and the light source 320 is changed from LED to halogen, the polarization direction is changed by rotating the first polarizing filter 101. This makes it possible to prevent the balance of the light amounts of the opening regions 132A to 132C from being lost.

[0105] Third Embodiment Next, a third embodiment will be described. In this embodiment, the first polarizing unit is composed of a first polarizing filter 101 having multiple regions whose polarization directions can be changed independently. The light intensity of the opening regions 132A to 132C is adjusted by rotating the first polarizing filter 101.

[0106] 20 is a conceptual diagram of a first polarizing filter 101 of this embodiment. The first polarizing filter 101 has three regions 101A to 101C, each of which can change its polarization direction independently. Each of the regions 101A to 101C can rotate around rotation axes LA to LC to change its polarization direction. Specifically, each of the regions 101A to 101C has one polarization direction, and by rotating around the rotation axes LA to LC, the polarization direction of light passing through the region can be changed. Furthermore, region 101A corresponds to aperture region 132A, region 101B corresponds to aperture region 132B, and region 101C corresponds to aperture region 132C.

[0107] In this manner, in this embodiment, the light amount in each region can be adjusted by the interaction between the polarization direction of regions 101A to 101C of first polarizing filter 101 and the polarization direction of the second polarizing filter.

[0108] Change in light intensity α of opening areas 132A to 132C i is expressed by the following formula (3): The change in the amount of light in opening region 132A is indicated by a change in amount of light α0, the change in the amount of light in opening region 132B is indicated by a change in amount of light α1, and the change in the amount of light in opening region 132C is indicated by a change in amount of light α2.

[0109]

number

[0110] In addition, the above formula (3) indicates the following values.

[0111]

number

[0112]

number

[0113] As described above, the amount of light in the opening regions 132A to 132C can be adjusted by the region of the first polarizing filter 101 and the second polarizing filters 148A to 148C.

[0114] An example of adjusting the light intensity of the opening regions 132A to 132C will be described below.

[0115] Seventh embodiment Table 513 in Fig. 21 is a table for explaining the adjustment of the light intensity in Example 7. Note that this example does not use the ND filter 142. Furthermore, the wavelength selection filters 144A to 144C and second polarization filters 148A to 148C arranged in each aperture region are the same as those in Example 1.

[0116] When light source 320 is halogen, by setting the polarization angle of region 101A of first polarizing filter 101 to 4°, the polarization angle of region 101B to 9°, and the polarization angle of region 101C to -2°, the ratio of the light amounts in opening regions 132A to 132C approaches 1:1:1, and the balance of the light amounts in each opening region can be improved. This is explained below using Table 513.

[0117] When the light source 320 is halogen, and the first polarizing filter 101 is not provided (initial state), the light intensity obtained is 40 in the opening region 132A ("B"), 100 in the opening region 132B ("G"), and 140 in the opening region 132C ("R") (item (1) in Table 513). When the polarization direction of the first polarizing filter 101 in the region 101A is set to 4°, the polarization direction of the region 101B is set to 9°, and the polarization direction of the region 101C is set to -2°, the change in the light intensity in each of the opening regions 132A to 132C is calculated using the above-mentioned formula (3) (item (2) in Table 513). Furthermore, by calculating the product of the initial light intensity when light source 320 is halogen and the calculated change in light intensity, the light intensity in aperture regions 132A-132C when regions 101A-101C of first polarizing filter 101 are set as described above can be calculated (item (3) in Table 513). The ratio of these light intensities is 1.005074:1:0.992668 (item (4) in Table 513), and by setting the polarization direction of region 101A of first polarizing filter 101 to 4°, the polarization direction of region 101B to 9°, and the polarization direction of region 101C to -2°, the light intensity balance of aperture regions 132A-132C can be improved.

[0118] When light source 320 is an LED, by setting the polarization direction of region 101A of first polarizing filter 101 at -71°, the polarization direction of region 101B at -8°, and the polarization direction of region 101C at -14°, the ratio of the light amounts in opening regions 132A to 132C approaches 1:1:1, and the balance of the light amounts in each opening region can be improved. This is explained below using Table 513.

[0119] When light source 320 is an LED, and first polarizing filter 101 is not provided (initial state), the light intensity obtained is 140 in aperture region 132A ("B"), 100 in aperture region 132B ("G"), and 30 in aperture region 132C ("R") (item (5) in Table 513). When the polarization direction of region 101A of first polarizing filter 101 is set to -71°, the polarization direction of region 101B is set to -8°, and the polarization direction of region 101C is set to -14°, the change in light intensity in each of aperture regions 132A to 132C is calculated using the above-mentioned formula (3) (item (6) in Table 513). Furthermore, by calculating the product of the initial light intensity when light source 320 is an LED and the calculated change in light intensity, the light intensity in aperture regions 132A-132C when regions 101A-101C of first polarizing filter 101 are set as described above can be calculated (item (7) in Table 513). The ratio of these light intensities is 1.057453:1:1.031604 (item (8) in Table 513), and by setting the polarization directions of regions 101A-101C of first polarizing filter 101 as described above, the light intensities of aperture regions 132A-132C can be well balanced.

[0120] As described above, by setting the polarization direction of regions 101A to 101C of first polarizing filter 101 at a predetermined angle, even if light source 320 is a halogen or LED, the ratio of the light intensity in opening regions 132A to 132C can be made close to 1:1:1, and the balance of the light intensity in each opening region can be improved.

[0121] <Another example of the first polarizing section> In the examples of the first to third embodiments described above, the first polarizing filter 101 is provided as the first polarizing unit on the object-side front surface of the imaging optical system 100A (see FIG. 5). However, other aspects of the first polarizing unit may also be employed in the present disclosure. Other examples of the first polarizing unit will be described below.

[0122] 22 is a diagram illustrating another example of the first polarizing unit. In this example, the first polarizing filter 101 constituting the first polarizing unit is rotatably arranged within the imaging optical system 100A. It is arranged closer to the object side than the wavelength polarizing filter unit 130. Specifically, the first polarizing filter 101 is arranged adjacent to the object side of the intermediate filter A so that it can rotate around the optical axis L. In this case, the first polarizing filter 101 is arranged at or near the pupil position of the imaging optical system 101A, and the first polarizing filter 101 is arranged adjacent to the object side of the intermediate filter A. This makes it possible to suppress the difference in light intensity that occurs between the portion of the aperture region close to the optical axis L and the peripheral portion.

[0123] FIG. 23 is a diagram illustrating another example of the first polarizing unit. In this example, the first polarizing unit is composed of a first polarizing filter 101 and a liquid crystal polarization rotator element C arranged on the image side of the first polarizing filter 101. The first polarizing filter 101 is fixed so as to transmit light having one polarization direction. The polarization direction of the light transmitted through the first polarizing filter 101 is then polarized by the liquid crystal polarization rotator element C. The liquid crystal polarization rotator element C changes the polarization direction of the light transmitted through the first polarizing filter 101 by changing the orientation of the liquid crystal molecules when an applied voltage is changed. This allows the polarization direction of the light transmitted through the first polarizing filter 101 to be freely changed.

[0124] <Control of polarization direction of first polarization unit> As described above, in the first to third embodiments, the polarization direction of the first polarization unit is controlled to adjust the light intensity of the opening regions 132A to 132C. The polarization direction of the first polarization unit is controlled automatically or manually as described below.

[0125] A case where the polarization direction of the first polarizing unit is automatically controlled will be described. For example, the polarization direction of the first polarizing unit is automatically controlled by a polarization direction control unit configured with a CPU provided in the lens device 100 or a CPU provided in the imaging device body 200. If the first polarizing unit is configured with a first polarizing filter 101 as described in the first embodiment, the polarization direction control unit rotates the first polarizing filter 101 to adjust the amount of light in the opening regions 132A to 132C. The polarization direction control unit rotates the first polarizing filter 101 to control the polarization direction of the first polarizing filter 101 based on the ratio of the amount of light in each of the opening regions 132A to 132C. The polarization direction control unit rotates the first polarizing filter 101 so as to achieve a good balance between the ratio of the amount of light in each of the opening regions 132A to 132C.

[0126] Next, a case where the polarization direction of the first polarizing unit is manually controlled will be described. For example, the lens device 100 includes a polarization direction control unit that controls the polarization direction of the first polarizing unit at a predetermined position. When the first polarizing unit is configured with the first polarizing filter 101 as described in the first embodiment, the polarization direction control unit is provided so that when the user manually rotates the first polarizing filter 101, the rotation stops at a position where the ratio of the light intensities of the aperture regions 132A to 132C is well balanced. In the first embodiment, when the light source 320 is a halogen light source, the polarization direction control unit is provided so that the rotation of the first polarizing filter 101 stops at a position 4° clockwise. When the light source 320 is an LED, the polarization direction control unit is provided so that the rotation of the first polarizing filter 101 stops at a position 63° counterclockwise. This allows the user to rotate the first polarizing filter 101 and stop it at a position where the ratio of the light intensities of the aperture regions 132A to 132C is well balanced.

[0127] <Fourth embodiment> Next, a fourth embodiment will be described. In the first to third embodiments described above, the first polarization section polarizes light rays passing through the imaging optical system 100A in various directions, and the amount of light in the aperture regions 132A to 132C is adjusted by the interaction of the polarization directions of the second polarization filters 148A to 148C. That is, in the first to third embodiments, the first polarization section was provided so as to be able to change the polarization direction of the light rays passing through it. In the fourth embodiment, instead of a first polarization section that can change the polarization direction of the light rays, a first polarization filter 101 with a fixed polarization direction is provided in the wavelength polarization filter unit 130.

[0128] 24 and 25 are conceptual diagrams showing the first polarizing filter 101 and the wavelength polarizing filter unit 130. The first polarizing filter 101 and the wavelength polarizing filter unit 130 are bonded together to form a single optical member. In the following description, the filter sets 140A to 140C will be collectively referred to as filter set 140, the ND filters 142A to 142C will be collectively referred to as ND filters 142, the wavelength selective filters 144A to 144C will be collectively referred to as wavelength selective filters 144, the optical path length correction filters 146A to 146C will be collectively referred to as optical path length correction filters 146, and the second polarizing filters 148A to 148C will be collectively referred to as second polarizing filters 148.

[0129] The wavelength polarization filter unit 130 of this embodiment includes a first polarization filter 101 on the object side. The polarization direction of the first polarization filter 101 shown in FIG. 24 is different from that of the first polarization filter 101 shown in FIG. 25. On the other hand, the polarization direction of the second polarization filter 148 in FIGS. 24 and 25 is the same. In this way, by preparing multiple optical members each with a different polarization direction of the first polarization filter 101 and replacing the optical member, the ratio of the light intensities of the aperture regions 132A to 132C can be changed. Furthermore, in the optical member described above, the first polarization filter 101 is positioned closest to the object and the second polarization filter 148 is positioned closest to the image, thereby reducing the light intensity of the aperture regions 132A to 132C and suppressing crosstalk between the aperture regions 132A to 132C.

[0130] <Filter set example> Next, a description will be given of the above-mentioned filter set 140. The arrangement of each filter constituting the filter set 140 will be described below.

[0131] First, the arrangement of the second polarizing filter 148 in the filter set 140 will be described.

[0132] 26 and 27 are diagrams illustrating the arrangement of the second polarizing filter 148. The filters indicated by the symbol X include an ND filter 142, a wavelength selection filter 144, and an optical path length correction filter 146. As shown in FIGS. 26 and 27, the second polarizing filter 148 is preferably arranged closest to the image in the filter set 140. By arranging the second polarizing filter 148 closest to the image in this way in the filter set 140, the second polarizing filter 148 can cancel out the polarization characteristics that occur when light passes through the other filters (the ND filter 142, the wavelength selection filter 144, and the optical path length correction filter 146).

[0133] In FIG. 27, all the filters of the filter set 140 are arranged on the object side of the frame 132, and therefore the second polarizing filter 148 is arranged on the image side of the area boundary member 132(α).

[0134] Next, the arrangement of the second polarizing filter 148 and the wavelength-selective filter 144 in the filter set 140 will be described.

[0135] 28 and 29 are diagrams illustrating the arrangement of the wavelength-selective filter 144 and the second polarizing filter 148. The filters indicated by the symbol X include an ND filter 142 and an optical path length compensation filter 146. As shown in FIGS. 28 and 29, the second polarizing filter 148 is arranged closer to the image side than the wavelength-selective filter 144. By arranging the second polarizing filter 148 closer to the image side than the wavelength-selective filter 144 in this way, the polarization characteristics that occur when light passes through the wavelength-selective filter 144 can be canceled out by the second polarizing filter 148.

[0136] Next, the arrangement of the ND filter 142 and the wavelength selection filter 144 in the filter set 140 will be described.

[0137] 30 is a diagram illustrating the arrangement of the ND filter 142 and the wavelength selection filter 144. The filter indicated by the symbol X includes an optical path length compensation filter 146 and a second polarization filter 148. As shown in FIG. 30, the ND filter 142 is arranged closer to the object than the wavelength selection filter 144. This makes it possible to suppress flare and ghosts caused by strong reflected light on the surface of the wavelength selection filter 144.

[0138] Next, the arrangement of the ND filters 142 in the filter set 140 will be described.

[0139] 31 and 32 are diagrams illustrating the arrangement of the ND filter 142. The filters indicated by the symbol X include a wavelength-selective filter 144, an optical path length compensation filter 146, and a second polarizing filter 148. In FIG. 31, the ND filter 142 is arranged closest to the object in the filter set 140. By arranging the ND filter 142 closest to the object in this way, ghosting can be suppressed by attenuating light before it is reflected by the wavelength-selective filter 144, and subsequent adjustments can be easily made. In FIG. 32, the ND filter 142 is arranged closest to the image in the filter set 140. This allows the ND filter 142 to be easily attached, and subsequent adjustments can be easily made.

[0140] Next, the arrangement of the optical path length correction filter 146 in the filter set 140 will be described.

[0141] 33 and 34 are diagrams illustrating the arrangement of the optical path length compensation filter 146. The filters indicated by the symbol X include an ND filter 142, a wavelength selection filter 144, and a second polarization filter 148. In FIG. 33, the optical path length compensation filter 146 is arranged closest to the object. In FIG. 34, the optical path length compensation filter 146 is arranged closest to the image. This makes it possible to easily attach the optical path length compensation filter 146 and facilitates subsequent adjustment.

[0142] Although examples of the present invention have been described above, it goes without saying that the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the present invention. [Explanation of symbols]

[0143] 10: Imaging device 100: Lens device 100A: Imaging optical system 100B: Lighting device 101: First polarizing filter 102: Telescope tube 108: Slit 110: First lens 120: Second lens 130: Wavelength polarization filter unit 132:Frame body 200: Imaging device body 210: Image sensor 211: Pixel array layer 212: Photodiode 213: Polarization filter element array layer 214A: Polarization filter element 214B: Polarization filter element 214C: Polarizing filter element 214D: Polarizing filter element 215: Microlens array layer 216: Microlens 230: Signal processing section 232: Analog signal processing section 234: Image generation unit 236: Coefficient memory unit 310: Light source control unit 320 :Light source L: Optical axis

Claims

1. an imaging optical system; a first polarization unit that polarizes at least a portion of light passing through the imaging optical system; a filter unit disposed on the image side of the first polarization section and disposed at or near a pupil position of the imaging optical system, the filter unit including: a plurality of aperture regions including a first aperture region and a second aperture region that transmit light rays of the imaging optical system; a plurality of wavelength selection filters disposed in the first aperture region and the second aperture region that transmit light having at least a portion of different wavelength bands; and a second polarization filter disposed in the first aperture region and the second aperture region that has a plurality of polarization filters with mutually different polarization directions; A lens device comprising: The first polarizing unit is a lens device having a variable polarization direction.

2. an imaging optical system; a first polarization unit that polarizes at least a portion of light passing through the imaging optical system; a filter unit disposed on the image side of the first polarization section and disposed at or near a pupil position of the imaging optical system, the filter unit including: a plurality of aperture regions including a first aperture region and a second aperture region that transmit light rays of the imaging optical system; a plurality of wavelength selection filters disposed in the first aperture region and the second aperture region that transmit light having at least a portion of different wavelength bands; and a second polarization filter disposed in the first aperture region and the second aperture region that has a plurality of polarization filters with mutually different polarization directions; A lens device comprising: The first polarization unit has a plurality of regions whose polarization directions can be changed independently, and the plurality of regions rotate along their respective rotation axes.

3. The lens device according to claim 2 , wherein the first polarizing unit has a variable polarization direction.

4. 4. The lens device according to claim 1, wherein the first polarizing unit is a first polarizing filter that rotates around an optical axis.

5. The lens device according to claim 1 , wherein the first polarization unit is disposed on the object side of a lens included in the imaging optical system.

6. The lens device according to claim 1 , wherein the first polarization unit is disposed in the imaging optical system and closer to the object side than the filter unit.

7. The lens device according to claim 1 , wherein the first polarizing section has a plurality of regions whose polarization directions are different from each other.

8. The lens device according to claim 1 , wherein the first polarization unit has a plurality of regions whose polarization directions can be changed independently, and the plurality of regions rotate along their respective rotation axes.

9. The lens device according to claim 1 , wherein the second polarizing filter is disposed on the image side of the plurality of wavelength-selective filters.

10. 10. The lens device according to claim 1, wherein the filter unit further includes a plurality of optical path length compensation filters arranged in the first opening region and the second opening region, the optical path length compensation filters compensating for axial chromatic aberration caused by the plurality of wavelength selection filters.

11. The lens device according to claim 1 , wherein the filter unit further includes an ND filter disposed in the first opening region and the second opening region, the ND filter reducing an amount of light from the imaging optical system.

12. a polarization direction control unit that controls the polarization direction of the first polarization unit at a predetermined position, 12. The lens device according to claim 1, wherein the polarization direction control unit controls the polarization direction of the first polarizer based on a ratio between the amount of light corresponding to the first opening region and the amount of light corresponding to the second opening region.

13. an imaging optical system; a first polarization unit that polarizes at least a portion of light passing through the imaging optical system; a filter unit disposed on the image side of the first polarization section and disposed at or near a pupil position of the imaging optical system, the filter unit including: a plurality of aperture regions including a first aperture region and a second aperture region that transmit light rays of the imaging optical system; a plurality of wavelength selection filters disposed in the first aperture region and the second aperture region that transmit light having at least a portion of different wavelength bands; and a second polarization filter disposed in the first aperture region and the second aperture region that has a plurality of polarization filters with mutually different polarization directions; A lens device comprising: The first polarization unit is a lens device composed of a polarizing filter and a liquid crystal polarization rotation element disposed on the image side of the polarizing filter.

14. a polarization direction control unit that controls the polarization direction of the first polarization unit at a predetermined position, The lens device according to claim 13 , wherein the polarization direction control section controls the polarization direction of the first polarizer based on a ratio between an amount of light corresponding to the first opening region and an amount of light corresponding to the second opening region.

15. an imaging optical system; a first polarization unit that polarizes at least a portion of light passing through the imaging optical system; a filter unit disposed on the image side of the first polarization section and disposed at or near a pupil position of the imaging optical system, the filter unit including: a plurality of aperture regions including a first aperture region and a second aperture region that transmit light rays of the imaging optical system; a plurality of wavelength selection filters disposed in the first aperture region and the second aperture region that transmit light having at least a portion of different wavelength bands; and a second polarization filter disposed in the first aperture region and the second aperture region that has a plurality of polarization filters with mutually different polarization directions; a polarization direction control unit that controls the polarization direction of the first polarization unit; A lens device comprising: The polarization direction control unit controls the polarization direction of the first polarization unit based on a ratio between the amount of light corresponding to the first opening region and the amount of light corresponding to the second opening region.

16. The lens device according to claim 15 , wherein the first polarizing unit has a variable polarization direction.

17. 17. The lens device according to claim 15, wherein the first polarizing unit is a first polarizing filter that rotates around an optical axis.

18. The lens device according to claim 15 , wherein the first polarization unit is disposed on the object side of a lens included in the imaging optical system.

19. The lens device according to claim 15 , wherein the first polarization unit is disposed in the imaging optical system and closer to the object side than the filter unit.

20. The lens device according to claim 15 , wherein the first polarizing section has a plurality of regions whose polarization directions are different from each other.

21. 20. The lens device according to claim 15, wherein the first polarization unit has a plurality of regions whose polarization directions can be changed independently, and the plurality of regions rotate along their respective rotation axes.

22. 22. The lens device according to claim 15, wherein the second polarizing filter is disposed on the image side of the plurality of wavelength-selective filters.

23. 23. The lens device according to claim 15, wherein the filter unit further includes a plurality of optical path length compensation filters arranged in the first opening region and the second opening region, and configured to compensate for axial chromatic aberration caused by the plurality of wavelength selection filters.

24. 24. The lens device according to claim 15, wherein the filter unit further includes an ND filter disposed in the first opening region and the second opening region, the ND filter reducing an amount of light from the imaging optical system.

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