Light field imaging device based on geometric phase lens

Abstract

The light field imaging device of the present invention may comprise: a linear polarizing plate; a first polarization switching element on which light passing through the linear polarizing plate is incident and which is electrically controlled to be turned on / off; a quarter-wave plate on which the light passing through the first polarization switching element is incident; and a first geometric phase lens on which the light passing through the quarter-wave plate is incident.

Description

Light field imaging device based on geometric phase lens

[0001] The present invention relates to a light field imaging device, and more specifically, to an imaging device using a geometric phase lens.

[0002]

[0003] Geometric phase (GP) lenses, optical devices composed of birefringent materials that satisfy the half-retardation condition, have recently attracted significant attention in various optical systems. GP lenses enable two distinct phase modulations within a single component, which are selectively activated depending on the state of the incident circular polarization. This feature allows the GP element to control the optical path in a polarization-dependent manner, significantly improving the efficiency of projection optical systems. Furthermore, GP lenses utilize their polarization-dependent optical properties to form multiple focal planes, effectively extending the depth representation of 3D displays in various applications, such as AR and VR devices.

[0004] Existing 2D imaging systems have limitations in perfectly reproducing the real world due to a lack of depth information. Light field acquisition technologies for representing light information existing in space can be broadly divided into methods based on multiple camera arrays and single-camera methods based on lens arrays. Conventionally, when using a camera to take pictures, the method of increasing the amount of light in a dark place usually requires increasing the exposure time or increasing the lens aperture size. However, increasing the exposure time causes motion blur when capturing fast-moving objects, and increasing the lens aperture size causes the camera DOF (Depth of Field) to decrease.

[0005] Compared to single-camera systems based on lens arrays, multi-camera array systems have the advantage of a relatively wide field of view. However, the system construction costs are high, and issues such as alignment between cameras, color mismatch due to differences in signal gain between cameras, and internal / external camera calibration must be resolved in advance to obtain the light field. Because specialized knowledge in the relevant field is required for practical use, the system is difficult for general users to operate. Furthermore, the bulkiness of the cameras themselves limits the ability to reduce the gap between cameras, which prevents the acquisition of light field information existing between cameras, which can result in poor image quality due to insufficient information during image generation.

[0006] To address these issues, light field systems based on multifocal MLAs or Liquid Crystal Micro Lens Arrays (LC-MLAs) have been developed. However, practical imaging applications remain challenging due to complex manufacturing processes, the low spatial resolution of multifocal MLAs, and the relatively low transparency of LC-MLAs. Therefore, alternative approaches that extend the depth of field from the main lens, rather than relying on MLAs, are warranted.

[0007] The present invention was derived from research conducted as part of the Future Display Strategy Research Lab support (R&D) of the Ministry of Science and ICT (Project Unique Number: 2710006333, Project Number: RS-2024-00416272, Project Management Agency: National Research Foundation of Korea, Research Project Title: Development of Source Technology for Focus Variable Chromatic Aberration Resolution and High-Efficiency / Large Diameter of Thin, Small, and Compact Geometric Phase Modulation Metalens for Next-Generation Glasses-Type XR Devices, Project Executing Agency: Kyungpook National University Industry-Academic Cooperation Foundation, Research Period: 2024.04.01~2028.12.31).

[0008] Meanwhile, the Korean government, which provided the task, has no property interest in any aspect of the present invention.

[0009]

[0010] One object of the present invention is to provide a light field imaging device including a geometric phase lens.

[0011]

[0012] A light field imaging device according to one embodiment may include a linear polarizing plate; a first polarizing switching element on which light passing through the linear polarizing plate is incident and whose on / off state is electrically controlled; a quarter-wave plate on which light passing through the first polarizing switching element is incident; and a first geometric phase lens on which light passing through the quarter-wave plate is incident.

[0013] Here, the first polarization switching element can be configured to reverse or maintain the polarization state of the incident linearly polarized light depending on the on / off state.

[0014] Here, the light passing through the first geometric phase lens is incident, and a second polarization switching element whose on / off state is electrically controlled may be further included; and a second geometric phase lens onto which the light passing through the second polarization switching element is incident.

[0015] Here, the diopter of the main lens of the light field imaging device may be the sum of the diopter of the first geometric phase lens and the diopter of the second geometric phase lens.

[0016] Here, when the first polarization switching element is in an on state and the second polarization switching element is in an off state, the incident light output from the linear polarization plate can have its polarization state converted by the first polarization switching element and can be converted into right-circular polarization by the quarter-wave plate.

[0017] Here, the first geometric phase lens converts the incident right-hand circular polarization into left-hand circular polarization and outputs it, and the second polarization switching element does not convert the polarization state of the incident light, and the second geometric phase lens can convert the incident left-hand circular polarization into right-hand circular polarization and output it.

[0018] Here, when the first polarization switching element is in an off state and the second polarization switching element is in an on state, the incident light output from the linear polarization plate can be converted into left-circular polarization by the quarter-wave plate without the polarization component being converted by the first polarization switching element.

[0019] Here, the first geometric phase lens converts the incident left-circular polarization into right-circular polarization and outputs it, the second polarization switching element converts the polarization state of the incident light, and the second geometric phase lens can convert the incident left-circular polarization into right-circular polarization and output it.

[0020] Here, when both the first polarization switching element and the second polarization switching element are in an on state, the incident light output from the linear polarizing plate can have its polarization component converted by the first polarization switching element and can be converted into right-circular polarization by the quarter-wave plate.

[0021] Here, the first geometric phase lens converts the incident right-circular polarization into left-circular polarization and outputs it, the second polarization switching element converts the polarization state of the incident right-circular polarization, and the second geometric phase lens converts the incident right-circular polarization into left-circular polarization and outputs it.

[0022] Here, when both the first polarization switching element and the second polarization switching element are in an off state, the incident light output from the linear polarizing plate can be converted into left-circular polarization by the quarter-wave plate without the polarization component being converted by the first polarization switching element.

[0023] Here, the first geometric phase lens converts the incident left-circular polarization into right-circular polarization and outputs it, and the second polarization switching element does not convert the polarization state of the incident light, and the second geometric phase lens can convert the incident right-circular polarization into left-circular polarization and output it.

[0024] Here, the depth of field of the light field imaging device may be proportional to the focal length of the main lens of the light field imaging device.

[0025]

[0026] According to one embodiment of the present invention, a light field imaging device including a geometric phase lens can be provided.

[0027]

[0028] Figure 1 is a drawing for explaining an example of the operation of a geometric phase lens.

[0029] FIGS. 2 and 3 are drawings for explaining a light field imaging device according to one embodiment.

[0030] FIGS. 4 to 8 are drawings for explaining a light field imaging device according to another embodiment.

[0031] Figure 9 is a drawing for explaining a Galilean optical system to which the optical system of the present invention is applied.

[0032] Fig. 10 is a drawing for explaining a Kepler optical system to which the optical system of the present invention is applied.

[0033]

[0034] Since the embodiments described in this specification are intended to clearly explain the idea of ​​the present invention to a person having ordinary skill in the art to which the present invention pertains, the present invention is not limited to the embodiments described in this specification, and the scope of the present invention should be interpreted to include modified or altered examples that do not depart from the idea of ​​the present invention.

[0035] The terms used in this specification have been selected from widely used terms, taking into account their functions in the present invention. However, these terms may vary depending on the intentions of those skilled in the art, precedents, or the emergence of new technologies in the technical field to which the present invention pertains. However, if a specific term is defined and used with an arbitrary meaning, the meaning of that term will be described separately. Therefore, the terms used in this specification should be interpreted based on the actual meaning of the term and the overall content of this specification, rather than simply the name of the term.

[0036] The drawings attached to this specification are intended to facilitate explanation of the present invention, and the shapes depicted in the drawings may be exaggerated as necessary to help understand the present invention, and therefore the present invention is not limited by the drawings.

[0037] In cases where it is determined that a specific description of the composition or function of a public notice related to the present invention in this specification may obscure the gist of the present invention, a detailed description thereof will be omitted as necessary.

[0038]

[0039] Figure 1 is a drawing for explaining an example of the operation of a geometric phase lens.

[0040] Referring to Figure 1, a geometric phase lens (GP Lens) has a dual-focus optical characteristic that switches to a convex mode under right-hand circular polarization (HCP) and a concave mode under left-hand circular polarization (LCP). Unlike conventional refractive lenses that adjust the focal length by changing the thickness or curvature of the medium, a geometric phase lens can provide an ultra-thin lens that can be manufactured on a substrate with a thickness of several micrometers.

[0041] Furthermore, by peeling only the polymer film from the substrate, a thin, flat lens can be created, which can then be transferred to the surface of other devices. This technology can contribute to reducing the volume and weight of optical devices required for next-generation displays while maintaining a size and weight similar to eyeglasses. This technology is attracting attention for its potential to create lightweight, ultra-thin, flat optical elements.

[0042] The light field imaging device of the present invention utilizes a liquid crystal-based polarizing element, such as a geometric phase lens, to provide a more efficient and portable optical system through electrical switching. The light field imaging device of the present invention will be described in detail below.

[0043]

[0044] FIGS. 2 and 3 are drawings for explaining a light field imaging device according to one embodiment.

[0045] The embodiments of FIGS. 2 and 3 relate to an example in which a light field imaging device includes a single geometric phase lens. However, the present invention is not limited thereto, and the light field imaging device of the present invention may include multiple geometric phase lenses. FIGS. 4 to 7 will describe a light field imaging device including two geometric phase lenses.

[0046] Referring to FIG. 2, a light field imaging device according to one embodiment may include a linear polarizing plate (110), a polarizing switching element (120), a quarter-wave plate (130), a geometric phase lens (140), and a convex lens (150). However, the present invention is not limited thereto, and the light field imaging device of the present invention may further include other components.

[0047] The linear polarizing plate (110) can be configured to convert incident light into light with a 90-degree linear polarization component. The light passing through the linear polarizing plate (110) can be incident on the polarization switching element (120). The polarization switching element (120) can be electrically turned on / off. Specifically, the polarization switching element (120) can transmit the polarization state of the incident light without polarization modulation depending on whether a voltage is applied. Alternatively, the polarization switching element (120) can be configured to delay the incident light under a half-wave plate condition depending on whether a voltage is applied, thereby converting the incident light into an outgoing polarization component orthogonal to the incident polarization.

[0048] The polarization switching element (120) may be configured to reverse or maintain the polarization state of incident linearly polarized light depending on its on / off state. For example, the polarization switching element (120) may be an electrical half-wave plate (Switchable-hwp), but is not limited thereto.

[0049] For example, referring to FIG. 2, when the state of the polarization switching element (120) is on, the polarization switching element (120) can convert the polarization component of the incident light. Also, referring to FIG. 3, for example, when the state of the polarization switching element (120) is off, the polarization switching element (120) may not convert the polarization component of the incident light.

[0050] Light passing through the polarization switching element (120) can be incident on a quarter wave plate (130). The quarter wave plate (130) can change the polarization state of the light depending on the conditions of the quarter wave plate. Light passing through the quarter wave plate (130) can be incident on a geometric phase lens (140). The geometric phase lens (140) can change the polarization state of the incident light as described in FIG. 1. For example, when left-circular polarization is incident on the geometric phase lens (140), the geometric phase lens (140) can output right-circular polarization. Also, for example, when right-circular polarization is incident on the geometric phase lens (140), the geometric phase lens (140) can output left-circular polarization.

[0051] Additionally, light passing through the geometric phase lens (140) can be incident on a convex lens (150). The convex lens (150) can convert a negative focal length into a positive focal length due to the geometric phase lens (140). Accordingly, the convex lens (150) can compensate for the phenomenon in which the focus is not focused on an area where an object is located due to the geometric phase lens (140).

[0052] The light field imaging device of the present invention is a device capable of selectively restoring a desired depth of field (DoF) through electrical switching of a polarization switching element. Accordingly, the device of the present invention can expand the depth of field (DoF) without compromising spatial resolution by depth compared to conventional devices, and can overcome the trade-off between spatial resolution and DoF of a focused plenoptic camera.

[0053] That is, the device of the present invention can be implemented in a portable and compact manner by using a GP lens, which is a polarization-dependent element based on a plenoptic, and can also provide a method for overcoming the trade-off relationship between the resolution and DoF of a focused plenoptic camera.

[0054]

[0055] FIGS. 4 to 8 are drawings for explaining a light field imaging device according to another embodiment.

[0056] Figures 4 to 8 relate to another embodiment in which a light field imaging device includes two geometric phase lenses. However, the present invention is not limited thereto, and the light field imaging device of the present invention may include three or more geometric phase lenses.

[0057] Referring to FIGS. 4 to 8, a light field imaging device according to another embodiment may include a linear polarizing plate (210), a first polarizing switching element (120), a first quarter wave plate (230), a first geometric phase lens (240), a second quarter wave plate (235), a second polarizing switching element (250), a third quarter wave plate (255), a second geometric phase lens (260), and a convex lens (270). If the light field imaging device includes three geometric phase lenses, the light field imaging device may also include a third polarizing switching element and a third geometric phase lens that are arranged adjacent to the second geometric phase lens (260). In this case, additional optical elements such as a third polarizing switching element, a fourth quarter wave plate, and a fifth quarter wave plate may also be arranged as needed.

[0058] The basic description of the linear polarizing plate (210) to the convex lens (270) may overlap with the description of the linear polarizing plate (110) to the convex lens (150) of FIGS. 2 and 3, so detailed descriptions are omitted.

[0059] A light field imaging device according to another embodiment may operate differently depending on the electrical on / off of the first polarization switching element (220) and the second polarization switching element (250). However, regardless of the on / off state of the polarization switching elements, the diopter of the main lens of the light field imaging device may be equal to the sum of the diopter of the first geometric phase lens (240) and the diopter of the second geometric phase lens (260).

[0060] Here, the diopter may mean the reciprocal of the focal length. Furthermore, the depth of field (DoF) of the light field imaging device may be proportional to the focal length of the main lens of the light field imaging device. Furthermore, the main lens of the light field imaging device may mean the main optical system of the light field imaging device, which includes a plurality of geometric phase lenses and other optical systems (e.g., a convex lens).

[0061] The light field imaging device of the present invention can selectively restore different depths of field (DoF) depending on the on / off combination of polarization switching elements, which has the advantage of being able to expand the overall depth, thereby overcoming the trade-off between spatial resolution and DoF.

[0062] Below, an example of the operation of a light field imaging device according to the on / off state of polarization switching elements is specifically described.

[0063]

[0064] Referring to FIG. 5, the first polarization switching element (220) may be in an on state, and the second polarization switching element (250) may be in an off state.

[0065] The light output from the linear polarizing plate (210) can have its polarization component converted by the first polarization switching element (220) that is turned on. Accordingly, the light whose polarization component has been converted can be incident on the first quarter wave plate (230) and converted into right-circular polarization by the first quarter wave plate (230).

[0066] Light converted into right-circular polarization by the first quarter wave plate (230) may be incident on the first geometric phase lens (240) and converted into left-circular polarization by the first geometric phase lens (240). The left-circular polarization may be incident on the second quarter wave plate (235), and the polarization component may be converted. The converted polarization may not be converted by the second polarization switching element (250) that is in the off state. In addition, the light output from the second polarization switching element (250) may be incident on the third quarter wave plate (255) again, and the polarization component may be converted. Accordingly, the light converted into left-circular polarization may be incident on the second geometric phase lens (260) and converted into right-circular polarization. Finally, the light may be output through the convex lens (270).

[0067]

[0068] Referring to FIG. 6, the first polarization switching element (220) may be in an off state, and the second polarization switching element (250) may be in an on state.

[0069] The light output from the linear polarizing plate (210) may not have its polarization component converted by the first polarizing switching element (220) that is in the off state. Accordingly, the unconverted light may be incident on the first quarter wave plate (230) and converted into left-circular polarization by the first quarter wave plate (230).

[0070] Light converted into left-circular polarization by the first quarter wave plate (230) may be incident on the first geometric phase lens (240) and converted into right-circular polarization by the first geometric phase lens (240). The right-circular polarization may be incident on the second quarter wave plate (235), and the polarization component may be converted. The converted polarization may have its polarization component converted by the second polarization switching element (250) that is in the on state. In addition, the light output from the second polarization switching element (250) may be incident on the third quarter wave plate (255) again, and the polarization component may be converted. Accordingly, the left-circular polarization may be incident on the second geometric phase lens (260) and converted into right-circular polarization. Finally, the light may be output through the convex lens (27).

[0071]

[0072] Referring to FIG. 7, both the first polarization switching element (220) and the second polarization switching element (250) can be in an on state.

[0073] The light output from the linear polarizing plate (210) can have its polarization component converted by the first polarization switching element (220) that is in the on state. Accordingly, the converted light can be incident on the first quarter wave plate (230) and converted into right-circular polarization by the first quarter wave plate (230).

[0074] Light converted into right-circular polarization by the first quarter wave plate (230) can be incident on the first geometric phase lens (240) and converted into left-circular polarization by the first geometric phase lens (240). The left-circular polarization can be incident on the second quarter wave plate (235), and the polarization component can be converted. The converted polarization can have its polarization component converted by the second polarization switching element (250) that is in the on state. In addition, the light output from the second polarization switching element (250) can be incident on the third quarter wave plate (255) again, and the polarization component can be converted. Accordingly, the right-circular polarization can be incident on the second geometric phase lens (260) and converted into left-circular polarization. Finally, the light can be output through the convex lens (270).

[0075]

[0076] Referring to FIG. 8, both the first polarization switching element (220) and the second polarization switching element (250) can be in an off state.

[0077] The light output from the linear polarizing plate (210) may not have its polarization component converted by the first polarizing switching element (220) that is in the off state. Accordingly, the unconverted light may be incident on the first quarter wave plate (230) and converted into left-circular polarization by the first quarter wave plate (230).

[0078] Light converted into left-circular polarization by the first quarter wave plate (230) may be incident on the first geometric phase lens (240) and converted into right-circular polarization by the first geometric phase lens (240). The right-circular polarization may be incident on the second quarter wave plate (235), and the polarization component may be converted. The converted light may not be converted by the second polarization switching element (250) that is in the off state. In addition, the light output from the second polarization switching element (250) may be incident on the third quarter wave plate (255) again, and the polarization component may be converted. Accordingly, the right-circular polarization may be incident on the second geometric phase lens (260) and converted into left-circular polarization. Finally, the light may be output through the convex lens (270).

[0079]

[0080] Figure 9 is a drawing for explaining a Galilean optical system to which the optical system of the present invention is applied.

[0081] Referring to FIG. 9, the present invention can also be used as a Galilean optical system that expands the depth of field (DoF) by applying an optical system based on a Galilean Progressive Lens (GPL). Conventional optical systems generally use a method of improving imaging performance by using a fixed-focus lens or a varifocal lens that can adjust the focus within a limited range.

[0082] However, existing methods have limitations such as limited depth of field and the requirement of complex mechanical systems for focus adjustment. The present invention aims to address these issues by providing a Galilean optical system including a GPL-based variable focus optical system, thereby implementing a system capable of expanding depth of field and variable focus imaging solely through optical means.

[0083] The GPL-based variable focus optical system of the present invention is based on Galilean optical systems and enables variable focus imaging. It comprises multiple refractive surfaces and optical elements. This allows for extended depth of field without the need for a specific adjustment mechanism. Furthermore, the inclusion of front and rear lens elements of the Galilean system enables imaging at various focal lengths. In the present invention, a virtual image plane is formed through the optical system, which performs the function of enabling depth detection without focus shifting.

[0084] The optical system of the present invention extends depth of field without the need for a focus adjustment mechanism, enabling imaging at various distances. Furthermore, focus shifting is possible without the need for conventional mechanical adjustments, and focus can be adjusted solely through optical means. Because depth of field can be extended without additional mechanisms, it allows for a lighter design compared to conventional lens systems, and can be applied to various fields such as virtual reality (VR), augmented reality (AR), computer vision, and medical imaging.

[0085] The present invention provides an optical system that extends the depth of field and enables variable focus imaging by improving the Galilean optical system by applying a GPL-based optical system, thereby overcoming the limitations of existing systems and suggesting the possibility of utilization in various fields of application.

[0086]

[0087] Fig. 10 is a drawing for explaining a Kepler optical system to which the optical system of the present invention is applied.

[0088] Referring to Fig. 10, a Keplerian optical system that extends the depth of field (DoF) by applying an optical system based on the Galilean Progressive Lens (GPL) of the present invention is described. Conventional optical systems generally use a method of improving imaging performance by using a fixed-focus lens or a varifocal lens that can adjust the focus within a limited range.

[0089] However, existing methods have limitations such as limited depth of field and the requirement of complex mechanical systems for focus adjustment. The present invention aims to address these issues by providing a Kepler optical system including a GPL-based variable focus optical system, thereby implementing a system capable of expanding depth of field and variable focus imaging solely through optical means.

[0090] The GPL-based variable focus optical system of the present invention is based on a Keplerian optical system, enabling variable focus imaging, and comprises multiple refractive surfaces and optical elements. This allows for extended depth of field without the need for a specific adjustment mechanism. Furthermore, unlike Galilean optical systems, the Keplerian system's lens arrangement has a telescopic configuration, enabling higher magnification and improved optical performance. In the present invention, a virtual image plane is formed through the optical system, which enables depth detection without the need for focus shifting.

[0091] The optical system of the present invention extends depth of field without the need for a focus adjustment mechanism, enabling imaging at various distances. Furthermore, focus shifting is possible without the need for conventional mechanical adjustments, and focus can be adjusted solely through optical means. Because depth of field can be extended without additional mechanisms, it allows for a lighter design compared to conventional lens systems, and can be applied to various fields such as virtual reality (VR), augmented reality (AR), computer vision, and medical imaging.

[0092] The present invention provides an optical system that extends the depth of field and enables variable focus imaging by improving the Keplerian optical system by applying a GPL-based optical system, thereby overcoming the limitations of existing systems and suggesting the possibility of utilization in various fields of application.

[0093]

[0094] As described above, the present invention can achieve various light outputs by using the on / off state of the polarization switching element and the geometric phase lens. The configuration of the light field camera imaging system using the geometric phase lens is based on a focused plenoptic camera, and both Keplerian and Galilean configurations can be applied.

[0095] A geometric phase lens is a type of optical system that can operate as a convex lens (+f) or a concave lens (-f) depending on the handedness of the passing circularly polarized light. When GPL1 and GPL2 are stacked, a dynamically switchable polarization control element can be used to vary the polarization state of light incident on GPL1, thereby forming a focal plane at two different distances.

[0096] Similarly, by controlling the polarization incident on GPL2, we can form focal planes at two additional different distances. Additionally, to compensate for the negative focal length caused by the two GPLs, we can additionally place a convex lens. The convex lens can convert the negative focal length caused by the two GPLs into a positive focal length. This allows the optical system to form focal planes at a total of four different distances. By stacking n geometric phase lenses, we can obtain 2^n focal planes at different distances.

[0097] The light field imaging device of the present invention can be utilized in various fields such as imaging systems, AR devices, and VR devices.

[0098]

[0099] Although the embodiments described above have been described by way of limited examples and drawings, those skilled in the art will appreciate that various modifications and variations can be made based on the above teachings. For example, appropriate results can still be achieved even if the described techniques are performed in a different order than described, and / or components of the described systems, structures, devices, circuits, etc. are combined or combined in a different manner than described, or are replaced or substituted with other components or equivalents.

[0100] Therefore, other implementations, other embodiments, and equivalents to the claims also fall within the scope of the claims described below.

Claims

1. In a light field imaging device, linear polarizer; A first polarization switching element that receives light passing through the linear polarizing plate and is electrically turned on / off; A quarter-wave plate onto which light passing through the first polarization switching element is incident; and A first geometric phase lens is included into which light passing through the above quarter-wave plate is incident. Light field imaging device.

2. In paragraph 1, The above first polarization switching element is configured to reverse or maintain the polarization state of incident linearly polarized light depending on the on / off state. Light field imaging device.

3. In paragraph 1, A second polarization switching element, into which light passing through the first geometric phase lens is incident and whose on / off state is electrically controlled; and Further comprising a second geometric phase lens onto which light passing through the second polarization switching element is incident. Light field imaging device.

4. In paragraph 3, The diopter of the main lens of the light field imaging device is the sum of the diopter of the first geometric phase lens and the diopter of the second geometric phase lens. Light field imaging device.

5. In paragraph 3, When the first polarization switching element is in the on state and the second polarization switching element is in the off state, The incident light output from the linear polarizing plate has its polarization state converted by the first polarization switching element and is converted into right-circular polarization by the quarter-wave plate. Light field imaging device.

6. In paragraph 5, The above first geometric phase lens converts the incident right-handed polarized light into left-handed polarized light and outputs it, The above second polarization switching element does not change the polarization state of the incident light, The above second geometric phase lens converts the incident left-hand polarized light into right-hand polarized light and outputs it. Light field imaging device.

7. In paragraph 3, When the first polarization switching element is in an off state and the second polarization switching element is in an on state, The incident light output from the linear polarizing plate is converted into left-circular polarization by the quarter-wave plate without the polarization component being converted by the first polarization switching element. Light field imaging device.

8. In paragraph 7, The above first geometric phase lens converts the incident left-handed polarized light into right-handed polarized light and outputs it, The second polarization switching element converts the polarization state of the incident light, The above second geometric phase lens converts the incident left-hand polarized light into right-hand polarized light and outputs it. Light field imaging device.

9. In paragraph 3, When both the first polarization switching element and the second polarization switching element are in an on state, The incident light output from the linear polarizing plate has its polarization component converted by the first polarization switching element and is converted into right-circular polarization by the quarter-wave plate. Light field imaging device.

10. In paragraph 9, The above first geometric phase lens converts the incident right-handed polarized light into left-handed polarized light and outputs it, The above second polarization switching element converts the polarization state of the incident right-circular polarization, The above second geometric phase lens converts the incident right-handed polarized light into left-handed polarized light and outputs it. Light field imaging device.

11. In paragraph 3, When both the first polarization switching element and the second polarization switching element are in an off state, The incident light output from the linear polarizing plate is converted into left-circular polarization by the quarter-wave plate without the polarization component being converted by the first polarization switching element. Light field imaging device.

12. In paragraph 11, The above first geometric phase lens converts the incident left-handed polarized light into right-handed polarized light and outputs it, The above second polarization switching element does not change the polarization state of the incident light, The above second geometric phase lens converts the incident right-handed polarized light into left-handed polarized light and outputs it. Light field imaging device.

13. In paragraph 4, The depth of field of the light field imaging device is proportional to the focal length of the main lens of the light field imaging device. Light field imaging device.

Images