WO2012004988A1 - 光路変換素子および撮像装置 - Google Patents

光路変換素子および撮像装置 Download PDF

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Publication number
WO2012004988A1
WO2012004988A1 PCT/JP2011/003858 JP2011003858W WO2012004988A1 WO 2012004988 A1 WO2012004988 A1 WO 2012004988A1 JP 2011003858 W JP2011003858 W JP 2011003858W WO 2012004988 A1 WO2012004988 A1 WO 2012004988A1
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WIPO (PCT)
Prior art keywords
phase modulation
light
light shielding
optical path
discrete
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Ceased
Application number
PCT/JP2011/003858
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English (en)
French (fr)
Japanese (ja)
Inventor
真司 内田
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Panasonic Corp
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Panasonic Corp
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Priority to US13/805,432 priority Critical patent/US8848276B2/en
Publication of WO2012004988A1 publication Critical patent/WO2012004988A1/ja
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/001—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
    • G02B13/0015—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design
    • G02B13/002—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design having at least one aspherical surface
    • G02B13/004—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design having at least one aspherical surface having four lenses
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
    • G02B26/06—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the phase of light
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/001—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
    • G02B13/0055—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras employing a special optical element
    • G02B13/0075—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras employing a special optical element having an element with variable optical properties
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/42—Diffraction optics, i.e. systems including a diffractive element being designed for providing a diffractive effect
    • G02B27/46—Systems using spatial filters

Definitions

  • the present invention relates to an optical path conversion element for changing an optical path and an imaging apparatus including the same.
  • phase modulation mask for example, a phase modulation mask, a focus variable liquid crystal lens, an optical lens, or a prism has been proposed as an optical path conversion element used in a conventional imaging apparatus.
  • optical path conversion elements an optical element having a geometrically specific shape is used to change the optical path (see, for example, Patent Document 1), or a refractive index is applied by applying a voltage to the optical element. There is one that changes the optical path by changing (for example, see Patent Document 2).
  • Patent Document 1 a pair of phase modulation masks are used as optical path conversion elements. By rotating one of the pair of phase modulation masks with respect to the other, the optical path is changed and the depth of field of the optical system is expanded.
  • one of the pair of phase modulation masks is fixedly disposed, and the other is disposed so as to be rotatable within a range of 90 degrees.
  • the rotatable phase modulation mask is arranged so as to cancel the phase modulation generated by the fixed phase modulation mask.
  • the pair of phase modulation masks substantially function as parallel plane plates, and do not give phase modulation to light passing through the pair of phase modulation masks.
  • the phase modulation mask arranged so as to be rotatable is rotated by 90 degrees.
  • the pair of phase modulation masks applies phase modulation to the light passing therethrough.
  • light passing through a pair of phase modulation masks is modulated in the X direction and the Y direction, respectively, and the optical path is changed two-dimensionally.
  • the pair of phase modulation masks described in Patent Document 1 can be switched between a state in which phase modulation is not applied and a state in which phase modulation is applied to light passing therethrough by being rotated 90 degrees.
  • the pair of phase modulation masks can change the optical path.
  • This variable focus liquid crystal lens is a liquid crystal cell in the shape of a lens in which liquid crystal molecules are aligned concentrically or radially.
  • the focal length can be changed by applying an electric field or a magnetic field from the outside to the variable focus liquid crystal lens to control the alignment state of the liquid crystal molecules and continuously changing the refractive index of the liquid crystal.
  • variable focus liquid crystal lens is used as an optical path conversion element.
  • an imaging device used for a digital still camera, a digital video camera, or the like from the viewpoint of improving the usability of the imaging device, a case where the depth of field is expanded and a case where the depth of field is not enlarged can be switched at high speed.
  • the imaging apparatus is required to switch the optical path at high speed.
  • variable focus liquid crystal lens using the change in the refractive index of the liquid crystal as shown in Patent Document 2
  • the response speed of the liquid crystal molecules is limited by the viscosity of the liquid crystal. Therefore, it is difficult to switch the optical path at high speed in the variable focus liquid crystal lens of Patent Document 2.
  • the temperature dependence of the refractive index of the liquid crystal element is larger than that of the optical glass. Especially when the focal length is changed by using the change of the refractive index of the liquid crystal, the imaging performance at the focal position is improved. Adversely affect. Therefore, the variable focus liquid crystal lens of Patent Document 2 has a problem that it is difficult to obtain a high-resolution image.
  • the present invention solves the above-described conventional problems, and provides an optical path conversion element capable of switching an optical path at high speed and obtaining a high-resolution image, and an imaging apparatus including the optical path conversion element. For the purpose.
  • a plurality of phase modulation units that apply phase modulation to light passing therethrough are formed discretely and the first light is transmitted.
  • the phase modulation mask and the light shielding member are arranged such that at least a part of the plate surface overlaps each other when viewed from the light incident direction, and at least one of the phase modulation mask and the light shielding member is It arrange
  • a plurality of phase modulation portions are discretely formed on the phase modulation mask, and a plurality of light shielding portions are discretely formed on the light shielding member. Therefore, by moving at least one of the phase modulation mask and the light shielding member in a direction crossing the light incident direction, the way in which the plurality of phase modulation units and the plurality of light shielding units overlap is changed, and the light subjected to the phase modulation is changed.
  • the amount can be varied. That is, since it is not necessary to move the phase modulation mask largely in order to change the amount of light subjected to phase modulation, the optical path can be switched at high speed. Furthermore, since there is no need to change the refractive index of the phase modulation mask itself, a liquid crystal element having a large temperature dependency of the refractive index may not be used as the phase modulation mask. Therefore, a high resolution image can be obtained.
  • the arrangement pattern of the phase modulation part in the phase modulation mask and the arrangement pattern of the light shielding part in the light shielding member are the same, and the shape and size of the light shielding part and the phase modulation part are the same. It is preferable that
  • the arrangement pattern of the phase modulation unit and the arrangement pattern of the light shielding unit are the same. That is, since the phase modulation unit and the light shielding unit can be overlapped, unnecessary stray light can be prevented from being generated, and good optical characteristics can be obtained.
  • phase modulation unit and the first transmission unit are alternately arranged in the intersecting direction, and in the light shielding member, the light shielding unit and the second transmission unit are It is preferable that they are arranged alternately in the crossing direction.
  • the phase modulation unit and the light shielding unit overlap each other.
  • the optical path can be switched with a smaller movement amount, the optical path can be switched at a higher speed.
  • the phase modulation mask includes a plurality of first transmission portions, and the light shielding member includes a plurality of second transmission portions.
  • the phase modulation mask includes the plurality of phase modulation portions.
  • the plurality of first transmission parts are arranged in a checkered pattern, and in the light shielding member, the plurality of light shielding parts and the plurality of second transmission parts are arranged in a checkered pattern. preferable.
  • an aperture ratio of 50% can be realized, and the phase modulation mask and the second modulation unit can cover the phase modulation unit when viewed from the incident direction of light.
  • a light shielding member can be arranged. That is, the optical path of light can be switched at high speed and a high-resolution image can be obtained, and a relatively large amount of light can be incident on the image sensor.
  • Each of the plurality of phase modulation sections has a curved surface for applying phase modulation on one surface, and each of the plurality of light shielding sections has a light shielding property on a substrate that transmits light.
  • the phase modulation mask and the light shielding member are formed of a plate surface on the side where the curved surface is formed and a plate surface on the side where the light shielding film is formed. It is preferable to arrange so as to face each other.
  • the distance between the curved surface for applying phase modulation and the light shielding film can be reduced.
  • unnecessary light generated by the phase modulation mask can be efficiently shielded by the light shielding film formed on the light shielding member, and good optical characteristics can be obtained.
  • an imaging apparatus includes the optical path conversion element described above, and a moving unit that moves at least one of the light shielding member and the phase modulation mask in the intersecting direction.
  • the moving means changes the phase so that the phase modulation unit and the light shielding unit change from a state where the phase modulation unit and the light shielding unit overlap as seen from the incident direction. It is preferable to move at least one of the modulation mask and the light shielding member in the intersecting direction.
  • the optical path can be switched at high speed. Furthermore, since it is not necessary to change the refractive index of the phase modulation mask itself, a high-resolution image can be obtained.
  • FIG. 1 is a diagram illustrating a configuration of an imaging apparatus according to an embodiment of the present invention.
  • FIG. 2 is a diagram showing a discrete phase modulation mask according to the embodiment of the present invention.
  • FIG. 3 is a diagram showing a discrete aperture according to the embodiment of the present invention.
  • FIG. 4 is a diagram for explaining the operation of the optical path conversion element according to the embodiment of the present invention.
  • FIG. 5A is a diagram showing an MTF characteristic before the optical path conversion element according to the embodiment of the present invention changes the optical path.
  • FIG. 5B is a diagram illustrating a defocus characteristic before the optical path conversion element according to the embodiment of the present invention changes the optical path.
  • FIG. 6A is a diagram showing the MTF characteristics after the optical path conversion element according to the embodiment of the present invention changes the optical path.
  • FIG. 6B is a diagram showing defocus characteristics after the optical path conversion element according to the embodiment of the present invention changes the optical path.
  • FIG. 1 is a diagram illustrating a configuration of an imaging apparatus according to an embodiment of the present invention.
  • the X direction, the Y direction, and the Z direction indicate directions orthogonal to each other.
  • the Z direction is a direction parallel to the optical axis.
  • the Z direction corresponds to the incident direction of light
  • the Y direction corresponds to the intersecting direction intersecting the incident direction of light.
  • the imaging apparatus 100 includes an optical path conversion element 10, a moving means 13, an optical lens system 14, a cover glass 15, and an imaging element 16.
  • the optical path conversion element 10 includes a discrete phase modulation mask 11 and a discrete aperture 12.
  • the optical path conversion element 10 is an element that can change the optical path, and includes a discrete phase modulation mask 11 and a discrete aperture 12.
  • the discrete phase modulation mask 11 is a plate-like phase modulation mask that can modulate the phase of light passing therethrough.
  • the discrete phase modulation mask 11 is disposed so as to be movable in the Y direction, which is a direction intersecting the light incident direction.
  • the discrete aperture 12 is a plate-shaped light shielding member that selectively shields light that has been phase-modulated by the discrete phase modulation mask 11 and light that has not been phase-modulated.
  • the discrete aperture 12 is fixedly installed with respect to the optical axis of the optical lens system 14.
  • the discrete phase modulation mask 11 and the discrete aperture 12 are arranged so that at least a part of the plate surface overlaps each other when viewed from the light incident direction. Specifically, the discrete phase modulation mask 11 and the discrete aperture 12 are disposed so as to overlap each other in all the regions where light enters.
  • the moving means 13 moves the discrete aperture 12 in a direction crossing the light incident direction. That is, the moving unit 13 changes the relative position between the discrete phase modulation mask 11 and the discrete aperture 12 in order to change the optical path.
  • the moving means 13 includes a high-speed drive mechanism for translating the discrete phase modulation mask 11 in the Y direction. More specifically, the moving means 13 includes, for example, a VCM (Voice Coil Motor) or a piezo actuator as a high-speed drive mechanism.
  • VCM Vehicle Coil Motor
  • piezo actuator as a high-speed drive mechanism.
  • the VCM is a driving element that moves the discrete phase modulation mask 11 by using a force generated by passing a current through a coil in a magnetic field.
  • a magnet or a coil is disposed around the discrete phase modulation mask 11. Use.
  • the piezo actuator is a drive element that moves the discrete phase modulation mask 11 using a displacement generated by applying a voltage to the piezo element, and a relatively free position regardless of the size of the discrete phase modulation mask 11. Can be arranged.
  • the optical path conversion element 10 allows the light subjected to phase modulation by the discrete phase modulation mask 11 to be discrete. It is possible to switch between a state of passing through the type aperture 12 and a state in which light that has not undergone phase modulation by the discrete type phase modulation mask 11 passes through the discrete type aperture 12. That is, the optical path conversion element 10 can change the optical path.
  • the optical lens system 14 is an optical lens system for transmitting light that has passed through the discrete aperture 12. That is, the optical lens system 14 forms an image on the imaging plane with the light that has passed through the optical path conversion element 10.
  • the optical lens system 14 includes a plurality of lenses, but may include only one lens.
  • the cover glass 15 is a member for protecting the image pickup surface of the image pickup device 16 and is installed so as to cover the image pickup surface of the image pickup device 16. Note that the cover glass 15 is not necessarily installed. That is, the imaging apparatus 100 may include the cover glass 15 as necessary for design.
  • the imaging element 16 is a solid-state imaging element such as a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) sensor.
  • the imaging element 16 converts light incident on the imaging surface via the optical path conversion element 10, the optical lens system 14, and the cover glass 15 into an electrical signal.
  • the discrete phase modulation mask 11, the discrete aperture 12, the optical lens system 14, the cover glass 15, and the image sensor 16 are arranged at predetermined positions, and are incident on the discrete phase modulation mask 11.
  • the light passes through the discrete aperture 12, passes through the optical lens system 14 and the cover glass 15, and forms an image on the imaging surface of the imaging device 16.
  • the discrete phase modulation mask 11 is disposed on the front side in the light incident direction with respect to the discrete aperture 12.
  • the discrete aperture 12 is disposed on the front side of the discrete phase modulation mask 11. It doesn't matter.
  • the discrete aperture 12 is disposed on the front side of the optical lens system 14, but is not necessarily disposed on the front side of the optical lens system 14. Depending on the optical specifications to be used, the discrete aperture 12 may be disposed at the center of the optical lens system 14, for example.
  • the light passing through the discrete phase modulation mask 11 is as parallel light as possible because the discrete aperture 12 can effectively shield the light.
  • the discrete phase modulation mask 11 and the discrete aperture 12 are arranged with a space therebetween, but it is preferable that the distance between them is as small and uniform as possible.
  • the discrete phase modulation mask 11 and the discrete aperture 12 are preferably arranged so that the surface of the discrete phase modulation mask 11 that gives phase modulation and the light shielding film forming surface of the discrete aperture 12 face each other. . That is, the discrete phase modulation mask 11 and the discrete aperture 12 are arranged such that the plate surface on the side where the curved surface shape for applying phase modulation is formed and the plate surface on the side where the light shielding film is formed are opposed to each other. It is preferable that it is installed in.
  • the optical path conversion element 10 can reduce the interval between the curved surface for applying the phase modulation and the light shielding film. As a result, the optical path conversion element 10 can efficiently shield unnecessary light generated by the discrete phase modulation mask 11 with the light shielding film of the discrete aperture 12 and obtain good optical characteristics. If the distance between the two is too large, unnecessary light passes through the discrete aperture 12 and reaches the image plane of the image sensor 16, which is not preferable.
  • FIG. 2 is a diagram showing a discrete phase modulation mask according to the embodiment of the present invention. Specifically, FIG. 2 shows a planar shape of the discrete phase modulation mask 11. FIG. 1 shows a cross-sectional shape of the discrete phase modulation mask 11.
  • the discrete phase modulation mask 11 has a plurality of discrete phase modulation portions 11a formed discretely.
  • a transmission part 11b that transmits light is formed in a region where the phase modulation part 11a is not formed.
  • the phase modulation units 11a and the transmission units 11b are alternately arranged in a crossing direction that intersects the light incident direction.
  • the phase modulation unit 11a and the transmission unit 11b are arranged in a checkered pattern. That is, the phase modulation unit 11a and the transmission unit 11b are alternately arranged in two directions orthogonal to each other (here, the X direction and the Y direction).
  • Each of the plurality of phase modulation units 11a and each of the plurality of transmission units 11b has a square shape with the same size.
  • the discrete phase modulation mask 11 is arranged so as to be movable in a crossing direction (here, the Y direction) crossing the light incident direction. That is, the discrete phase modulation mask 11 is moved in the Y direction by the moving means 13.
  • the phase modulation unit 11a is a part that applies phase modulation to light passing therethrough. Specifically, in the phase modulation unit 11a, a curved surface shape for applying phase modulation is formed on one surface, and a planar shape is formed on the other surface.
  • k is a constant.
  • the phase modulation unit 11a can apply phase modulation to light passing therethrough.
  • the optical path conversion element 10 can expand the depth of field.
  • the transmission part 11b corresponds to a first transmission part and transmits light. That is, the transmission part 11b does not give phase modulation to the passing light.
  • the transmissive portion 11b has a planar shape parallel to each other on both surfaces.
  • such a discrete phase modulation mask 11 is obtained by replacing a part of the curved surface shape formed in the cubic phase modulation mask with a planar shape. It can also be said that the discrete phase modulation mask 11 is a discretized shape of the curved surface formed in the cubic phase modulation mask.
  • the curved surface shape formed in the phase modulation part 11a does not necessarily need to be a curved surface shape as described above.
  • the curved surface shape may be a spherical lens shape, an aspheric lens shape, a Fresnel lens shape, or a shape based on a polynomial function different from the above.
  • the curved surface shape formed in the phase modulation unit 11a may be a curved surface shape based on a quartic function. That is, the curved surface shape formed in the phase modulation unit 11a may be a curved surface shape formed in a QPM (Quality Phase Mask).
  • the curved surface shape formed in the phase modulation unit 11a may be a lens shape used for expanding the depth of field in a normal optical lens system. Even in these cases, the phase modulation unit 11a can apply phase modulation to light passing therethrough, and the optical path conversion element 10 can expand the depth of field.
  • the optical path conversion element 10 does not necessarily have to expand the depth of field. That is, the optical path conversion element 10 only needs to change the optical path. Specifically, the optical path conversion element 10 may be able to change the focal length by changing the optical path, for example.
  • the discrete phase modulation mask 11 is made of, for example, an optical glass material or a resin material.
  • an optical glass material a transparent glass material such as BK7, FD60, white plate glass, or quartz is preferable.
  • the resin material for example, a cycloolefin polymer resin having a small thermal expansion coefficient is suitable.
  • the discrete phase modulation mask 11 is manufactured by cutting or molding an optical glass material or a resin material, for example.
  • the discrete phase modulation mask 11 is preferably manufactured by molding rather than by cutting from the viewpoint of mass productivity.
  • FIG. 3 is a diagram showing a discrete aperture according to the embodiment of the present invention.
  • FIG. 3 shows the planar shape of the discrete aperture 12.
  • the discrete aperture 12 is formed with a plurality of light shielding portions 12a that shield light. Further, in the discrete aperture 12, a transmissive portion 12b that transmits light is formed in a region where the light shielding portion 12a is not formed.
  • the transmission part 12b corresponds to a second transmission part.
  • the light shielding parts 12a and the transmission parts 12b are alternately arranged in the intersecting direction intersecting the light incident direction.
  • the light shielding part 12a and the transmission part 12b are arranged in a checkered pattern. That is, the light-shielding part 12a and the transmission part 12b are alternately arranged in two directions orthogonal to each other (here, the X direction and the Y direction).
  • Each of the plurality of light shielding portions 12a and each of the plurality of transmission portions 12b has a square shape having the same size.
  • the arrangement pattern of the phase modulation section 11a in the discrete phase modulation mask 11 and the arrangement pattern of the light shielding section 12a in the discrete aperture 12 are the same.
  • the discrete aperture 12 is manufactured, for example, by discretely forming a plurality of light shielding films on a transparent substrate.
  • the region where the light shielding film is formed corresponds to the light shielding portion 12a, and the region where the light shielding film is not formed corresponds to the transmission portion 12b.
  • optical glass As the substrate material of the discrete aperture 12, for example, optical glass or resin film is used.
  • the optical glass it is preferable to use a transparent glass material such as BK7, FD60, white plate glass, or quartz.
  • the light shielding film formed on the optical glass is formed by using, for example, a sputtering method, an electron beam evaporation method, a spin coating method, or the like.
  • a material for the light shielding film a metal material such as chromium, tungsten, or titanium, or a light shielding resin material in which a black pigment is dispersed in a resin is used.
  • a light-shielding film having an appropriate thickness it is possible to form a light-shielding film that blocks light that is transmitted and that reflects little light from the light-shielding film.
  • the light-shielding film pattern can be formed by a known technique such as lithography, electron beam drawing, or mask vapor deposition.
  • the manufacturing method of the discrete aperture 12 need not be limited to the above.
  • the discrete apertures 12 may be manufactured by forming through holes in a light-shielding substrate.
  • the region where the through hole is not formed corresponds to the light shielding portion 12a
  • the region where the through hole is formed corresponds to the transmission portion 12b.
  • FIG. 4 is a diagram for explaining the operation of the optical path conversion element according to the embodiment of the present invention.
  • FIG. 4A shows a state where the light passing through the optical path conversion element 10 is not subjected to phase modulation.
  • FIG. 4B shows a state where light passing through the optical path conversion element 10 undergoes phase modulation.
  • the discrete phase modulation mask 11 and the discrete aperture 12 are arranged in a specific positional relationship. That is, the discrete phase modulation mask 11 and the discrete aperture 12 are arranged such that the transmission part 11b of the discrete phase modulation mask 11 and the transmission part 12b of the discrete aperture 12 overlap each other when viewed from the light incident direction. Yes. As a result, the light that has not undergone phase modulation that has passed through the transmission portion 11 b passes through the discrete aperture 12 and enters the optical lens system 14.
  • the discrete phase modulation mask 11 and the discrete aperture 12 are the light incident directions of the phase modulation unit 11a of the discrete phase modulation mask 11 and the light shielding unit 12a of the discrete aperture 12. Are arranged so as to overlap each other. Thereby, the light subjected to the phase modulation that has passed through the phase modulation unit 11 a is blocked by the light shielding unit 12 a and does not enter the optical lens system 14.
  • phase modulation is not given to the light that has passed through the optical path conversion element 10.
  • the moving means 13 moves the discrete phase modulation mask 11 in the Y direction by the distance between the centers of the phase modulation section 11a and the transmission section 11b adjacent to each other, the state changes to the state shown in FIG. To do.
  • the discrete phase modulation mask 11 and the discrete aperture 12 are arranged such that the phase modulation section 11a of the discrete phase modulation mask 11 and the transmission section 12b of the discrete aperture 12 overlap. Yes. Thereby, the light subjected to the phase modulation that has passed through the phase modulation unit 11 a passes through the discrete aperture 12 and enters the optical lens system 14.
  • the discrete phase modulation mask 11 and the discrete aperture 12 are such that the transmission portion 11b of the discrete phase modulation mask 11 and the light shielding portion 12a of the discrete aperture 12 are from the incident direction of light. They are arranged so as to overlap each other. As a result, the light that has not undergone the phase modulation that has passed through the transmission portion 11 b is blocked by the light shielding portion 12 a and does not enter the optical lens system 14.
  • phase modulation is given to the light that has passed through the optical path conversion element 10.
  • the light subjected to phase modulation in this way forms an image on the imaging surface of the imaging device 16 via the optical lens system 14 and the cover glass 15. At this time, the effect of phase modulation appears and the depth of field is expanded.
  • the moving means 13 when the moving means 13 is viewed from the incident direction of light, the phase modulation section 11a and the transmission section 12b are separated from the state in which the phase modulation section 11a and the light shielding section 12a overlap ((a) in FIG. 4).
  • the discrete phase modulation mask 11 is moved in a direction crossing the light incident direction so as to change to an overlapping state (FIG. 4B).
  • the moving means 13 can change at high speed from a state in which phase modulation is not applied to light passing therethrough to a state in which phase modulation is applied.
  • the discrete aperture 12 covers the entire region through which the light of the discrete phase modulation mask 11 passes in either of the states of FIG. 4 (a) and FIG. 4 (b). Thereby, it is possible to suppress generation of unnecessary stray light in the light passing through the discrete phase modulation mask 11 and the discrete aperture 12.
  • FIG. 5A is a diagram showing an MTF characteristic before the optical path changing element according to the embodiment of the present invention changes the optical path.
  • FIG. 5B is a diagram showing defocus characteristics before the optical path conversion element according to the embodiment of the present invention changes the optical path. That is, FIG. 5A and FIG. 5B are diagrams showing optical characteristics in the state shown in FIG.
  • the vertical axis represents MTF (Modulation Transfer Function) representing the height of resolution
  • the horizontal axis represents spatial frequency.
  • FIG. 5A shows that the degree of decrease in MTF when the spatial frequency is increased is relatively small. That is, it can be seen that relatively good resolution performance can be obtained even when the optical path conversion element 10 is used.
  • the vertical axis indicates MTF
  • the horizontal axis indicates the distance from the focal position. From FIG. 5B, it can be seen that good resolution performance is obtained in the vicinity of the focal position, but the resolution performance deteriorates rapidly as the distance from the focal position increases.
  • FIG. 6A is a diagram showing the MTF characteristics after the optical path conversion element according to the embodiment of the present invention changes the optical path.
  • FIG. 6B is a diagram showing defocus characteristics after the optical path conversion element according to the embodiment of the present invention changes the optical path. That is, FIG. 6A and FIG. 6B are diagrams showing the optical characteristics in the state shown in FIG. 4B.
  • the optical path conversion element 10 can expand the depth of field while obtaining a relatively good resolution performance.
  • the plurality of phase modulation units 11 a are discretely formed on the discrete phase modulation mask 11, and the plurality of light shielding units 12 a are formed on the discrete aperture 12. It is formed discretely. Therefore, by moving the discrete phase modulation mask 11 in a direction crossing the light incident direction, the overlapping of the plurality of phase modulation units 11a and the plurality of light shielding units 12a is changed, and the amount of light subjected to phase modulation Can be changed.
  • the optical path conversion element 10 since the optical path conversion element 10 does not need to move the discrete phase modulation mask 11 greatly in order to change the amount of light subjected to phase modulation, the optical path can be switched at high speed. Furthermore, in the optical path conversion element 10, since it is not necessary to change the refractive index of the discrete phase modulation mask 11 itself, a liquid crystal element having a large temperature dependency of the refractive index may not be used as the phase modulation mask. Therefore, according to the optical path conversion element 10, a high-resolution image can be obtained.
  • the arrangement pattern of the phase modulation unit 11a and the arrangement pattern of the light shielding unit 12a are the same. That is, since the optical path conversion element 10 can superimpose the phase modulation unit 11a and the light shielding unit 12a, generation of unnecessary stray light can be suppressed, and good optical characteristics can be obtained.
  • the optical path conversion element 10 if the discrete phase modulation mask 11 is moved by the distance between the centers of the phase modulation unit 11a and the transmission unit 11b adjacent to each other in the crossing direction, the phase It is possible to change from a state where the modulation unit 11a and the light shielding unit 12a overlap to a state where the phase modulation unit 11a and the transmission unit 12b overlap. In other words, since the optical path can be switched with a small amount of movement, the optical path can be switched at high speed.
  • the aperture ratio of the discrete aperture 12 is large in order to increase the amount of light incident on the image sensor 16.
  • the discrete aperture 12 can achieve an aperture ratio of 50%.
  • either the light shielding part 12a or the transmission part 12b can be arranged so as to cover the phase modulation part 11a. That is, the optical path conversion element 10 can switch the optical path of light at high speed and can obtain a high-resolution image, and can make a relatively large amount of light incident on the imaging element. .
  • the phase modulation unit 11a is slightly transmitted without passing through the substrate of the phase modulation mask, as in the conventional phase modulation mask.
  • the optical path conversion element 10 By simply moving the discrete phase modulation mask 11 by an interval from the unit 11b, it is possible to easily switch between a state in which phase modulation is not applied to light and a state in which phase modulation is applied. Therefore, according to the optical path conversion element 10, the optical path can be changed at a higher speed than in the prior art.
  • the optical path conversion element according to one aspect of the present invention and the imaging device including the optical path conversion element have been described based on the embodiments.
  • the present invention is not limited to these embodiments. Unless it deviates from the meaning of this invention, the form which gave various deformation
  • the moving means 13 has moved the discrete phase modulation mask 11, but may move the discrete aperture 12. That is, the moving unit 13 only needs to be able to change the relative positional relationship between the discrete phase modulation mask 11 and the discrete aperture 12 when viewed from the incident direction of light.
  • the plurality of phase modulation portions 11a and the plurality of transmission portions 11b are arranged in a checkered pattern, but it is not always necessary to arrange them in a checkered pattern. Therefore, the shapes of the phase modulation unit 11a and the transmission unit 11b are not necessarily square. In the discrete phase modulation mask 11, the phase modulation units 11 a and the transmission units 11 b do not necessarily have to be arranged alternately. Furthermore, the arrangement pattern of the phase modulation unit 11 a in the discrete phase modulation mask 11 and the arrangement pattern of the light shielding unit 12 a in the discrete aperture 12 do not necessarily have to be the same.
  • the imaging apparatus 100 can switch the optical path at high speed.
  • the moving means 13 has moved the discrete phase modulation mask 11 by the center-to-center distance between the phase modulation section 11a and the transmission section 11b adjacent to each other, but this distance is not necessarily required. Absent.
  • the moving means 13 may move the discrete phase modulation mask 11 by a distance that is twice or three times the distance between the centers.
  • the shapes of the discrete phase modulation mask 11 and the discrete phase modulation mask 11 shown in the above embodiment are examples, and may be, for example, a polygonal shape such as a quadrangle or a hexagon.
  • the optical path conversion element according to the present invention is useful for a digital still camera, a digital video camera, or the like.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Lenses (AREA)
  • Mechanical Light Control Or Optical Switches (AREA)
  • Optical Elements Other Than Lenses (AREA)
  • Studio Devices (AREA)
PCT/JP2011/003858 2010-07-09 2011-07-06 光路変換素子および撮像装置 Ceased WO2012004988A1 (ja)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US13/805,432 US8848276B2 (en) 2010-07-09 2011-07-06 Optical-path conversion device and imaging apparatus

Applications Claiming Priority (2)

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JP2010-156943 2010-07-09
JP2010156943A JP5380382B2 (ja) 2010-07-09 2010-07-09 光路変換素子および撮像装置

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NO348955B1 (no) * 2014-02-28 2025-07-28 Pgs Geophysical As Optisk bevegelsessensor
DE102015119255A1 (de) * 2015-11-09 2017-05-11 Carl Zeiss Microscopy Gmbh Einstellbare Phasenmaske, Mikroskop und Verfahren zur Phasenkontrastmikroskopie
KR102812099B1 (ko) 2019-05-16 2025-05-23 엘지이노텍 주식회사 카메라 모듈

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JPH01149610U (enExample) * 1988-04-05 1989-10-17
JP2000098303A (ja) * 1998-09-21 2000-04-07 Olympus Optical Co Ltd 拡大被写界深度光学系
JP2000160963A (ja) * 1998-09-22 2000-06-13 Hiroshi Imai ブラインド装置
JP2002040336A (ja) * 2000-07-21 2002-02-06 Fuji Photo Film Co Ltd 光変調素子及びそれを用いた露光装置並びに平面表示装置
JP2002062489A (ja) * 2000-08-22 2002-02-28 Canon Inc 光変調装置、該装置による光スイッチ、移動量検出装置及び該装置による距離測定装置、位置合わせ装置及び該装置による半導体露光装置、並びにこれらの方法

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Publication number Priority date Publication date Assignee Title
JPS61138922A (ja) 1984-12-11 1986-06-26 Jiesu:Kk 可変焦点液晶レンズ
JP2009098303A (ja) * 2007-10-15 2009-05-07 Casio Comput Co Ltd オートフォーカス装置、オートフォーカス方法及びプログラム
JP4524708B2 (ja) * 2008-06-19 2010-08-18 ソニー株式会社 再生装置、再生方法

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Publication number Priority date Publication date Assignee Title
JPH01149610U (enExample) * 1988-04-05 1989-10-17
JP2000098303A (ja) * 1998-09-21 2000-04-07 Olympus Optical Co Ltd 拡大被写界深度光学系
JP2000160963A (ja) * 1998-09-22 2000-06-13 Hiroshi Imai ブラインド装置
JP2002040336A (ja) * 2000-07-21 2002-02-06 Fuji Photo Film Co Ltd 光変調素子及びそれを用いた露光装置並びに平面表示装置
JP2002062489A (ja) * 2000-08-22 2002-02-28 Canon Inc 光変調装置、該装置による光スイッチ、移動量検出装置及び該装置による距離測定装置、位置合わせ装置及び該装置による半導体露光装置、並びにこれらの方法

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JP5380382B2 (ja) 2014-01-08
JP2012018355A (ja) 2012-01-26
US8848276B2 (en) 2014-09-30

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