Faraday plane lens, optical lens and imaging module

Abstract

The utility model provides a Faraday plane lens, an optical lens and an imaging module, which can solve the energy loss of the conventional folding optics and realize 100% theoretical transmittance. The Faraday planar lens includes: a Faraday element; the two phase delay elements are correspondingly attached to the surfaces of the two opposite sides of the Faraday element respectively, and the fast axis included angle between the two phase delay elements is 45 degrees; the two CLC body holographic elements are correspondingly attached to the outer side surfaces of the two phase delay elements respectively, and each CLC body holographic element is provided with an alignment layer for recording lens information and a cholesteric liquid crystal layer which is stacked on the alignment layer and is of a periodic spiral structure. And the spiral shaft of the cholesteric liquid crystal layer is vertical to the incident surface and is used for selectively reflecting circularly polarized light with the same chirality to modulate the propagation direction and selectively transmitting circularly polarized light with the opposite chirality to maintain the propagation direction.

Description

Technical Field

[0001] The utility model relates to the technical field of folded optics, in particular to a Faraday plane lens, an optical lens and an imaging module. Background Art

[0002] The existing folded optics (Pancake solution) is mainly based on the principle of polarized light to form a folded optical path based on reflective polarization. For example, the existing folded optical solution usually uses the characteristics of CLC (English: Cholesteric Liquid Crystal; Chinese: Cholesteric Liquid Crystal) lens that selectively reflects and transmits different polarized light, and cooperates with a 1 / 4 wave plate to adjust the shape of polarized light, so as to achieve back and forth reflection of light between the semi-reflective and semi-transparent lens and the CLC lens, and finally transmit it out from the CLC lens.

[0003] However, since the half-reflecting half-mirror reflects half of the light and transmits the other half, the light loses half of its energy when reflected or transmitted through the half-reflecting half-mirror. Therefore, the light energy utilization rate of the existing folding optical scheme is usually less than 25%, that is, the transmittance of the existing folding optical scheme is usually below 25%. As a result, VR devices using the existing folding optical scheme have to be equipped with higher-power displays, which not only increases power consumption and shortens its battery life, but also significantly increases weight, affecting the user's wearing comfort. Utility Model Content

[0004] One advantage of the present application is that it provides a Faraday plane lens, an optical lens, and an imaging module, which can solve the energy loss of existing folded optics and achieve a theoretical transmittance of 100%, so as to perfectly replace the application of traditional curved lenses in optical imaging and other scenarios.

[0005] Another advantage of the present application is to provide a Faraday plane lens, an optical lens and an imaging module, wherein, in one embodiment of the present invention, the Faraday plane lens can superimpose the focusing capabilities of two CLC volume holographic elements to achieve twice the focusing capability.

[0006] Another advantage of the present application is to provide a Faraday plane lens, an optical lens, and an imaging module, wherein in order to achieve the above-mentioned purpose, no expensive materials or complex structures are required in the present invention. Therefore, the present invention successfully and effectively provides a solution, not only providing a simple Faraday plane lens, an optical lens, and an imaging module, but also increasing the practicality and reliability of the Faraday plane lens, the optical lens, and the imaging module.

[0007] In order to achieve at least one of the above advantages or other advantages and purposes of the present application, the present invention provides a Faraday plane lens, comprising:

[0008] A Faraday element is used to rotate linear polarized light passing through one direction by 45° and to rotate linear polarized light passing through two directions by 90°;

[0009] A pair of phase delay elements, wherein the two phase delay elements are respectively attached to the opposite side surfaces of the Faraday element, and the fast axis angle between the two phase delay elements is 45°, and are used for converting linear polarized light into circular polarized light; and

[0010] A pair of CLC volume hologram elements, the two CLC volume hologram elements are respectively and correspondingly attached to the outer surfaces of the two phase delay elements, wherein each of the CLC volume hologram elements has an alignment layer for recording lens information and a cholesteric liquid crystal layer stacked on the alignment layer and having a periodic spiral structure, and the spiral axis of the cholesteric liquid crystal layer is perpendicular to the light incident surface of the CLC volume hologram element, and is used for selectively reflecting circularly polarized light with the same chirality as the CLC volume hologram element to modulate the propagation direction, and selectively transmitting circularly polarized light with an opposite chirality to the CLC volume hologram element to maintain the propagation direction.

[0011] According to some embodiments of the present application, the Faraday element is a non-reciprocal Faraday polarization rotator.

[0012] According to some embodiments of the present application, the phase delay element is a quarter wave plate.

[0013] According to some embodiments of the present application, the two CLC volume holographic elements have spiral structures with opposite handedness.

[0014] According to some embodiments of the present application, the two CLC volume holographic elements are respectively a left-handed CLC volume holographic film and a right-handed CLC volume holographic film; the phase delay element located on the left is a first 1 / 4 wave plate arranged with the fast axis tilted at -45°, and the phase delay element located on the right is a second 1 / 4 wave plate arranged with the fast axis vertically.

[0015] According to some embodiments of the present application, the two CLC volume holographic elements have spiral structures with the same handedness.

[0016] According to some embodiments of the present application, the two CLC volume holographic elements are both left-handed CLC volume holographic films or right-handed CLC volume holographic films; the phase delay element located on the left is a third 1 / 4 wave plate with the fast axis tilted 45°, and the phase delay element located on the right is a second 1 / 4 wave plate with the fast axis vertically arranged.

[0017] According to another aspect of the present application, the present application further provides an optical lens, comprising:

[0018] Lens tube;

[0019] Any of the above-mentioned Faraday plane lenses, wherein the Faraday plane lens is assembled inside the lens barrel.

[0020] According to some embodiments of the present application, the optical lens further includes a curved lens, and the curved lens is arranged coaxially with the Faraday plane lens.

[0021] According to another aspect of the present application, the present application further provides an imaging module, including:

[0022] Photosensitive components; and

[0023] The above-mentioned optical lens is arranged on the photosensitive side of the photosensitive component. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a schematic structural diagram of a Faraday plane lens according to an embodiment of the present application;

[0025] Figure 2 A schematic diagram of the folded optical path of the Faraday plane lens according to the above embodiment of the present application is shown;

[0026] Figure 3 A first example of a Faraday plane lens according to the above embodiment of the present application is shown;

[0027] Figure 4 A schematic diagram of the fast axis of the first quarter wave plate in the Faraday plane lens according to the first example of the present application is shown;

[0028] Figure 5 A schematic diagram of the fast axis of the second quarter wave plate in the Faraday plane lens according to the first example of the present application is shown;

[0029] Figure 6 A second example of the Faraday plane lens according to the above embodiment of the present application is shown;

[0030] Figure 7 A third example of the Faraday plane lens according to the above embodiment of the present application is shown;

[0031] Figure 8 A fast axis schematic diagram of the third quarter wave plate in the Faraday plane lens according to the third example of the present application is shown;

[0032] Fig. 9 A fourth example of the Faraday plane lens according to the above embodiment of the present application is shown;

[0033] Fig.10 is a schematic block diagram of an imaging module according to an embodiment of the present application;

[0034] Fig.11 is a schematic flow chart of a method for manufacturing a Faraday plane lens according to an embodiment of the present application;

[0035] Fig.12 An example of a CLC volume holographic element manufacturing step in the method for manufacturing a Faraday plane lens according to the above embodiment of the present application is shown;

[0036] Fig.13A and Fig. 13B It is a flowchart of a Faraday imaging method according to an embodiment of the present application.

[0037] Explanation of the main component symbols: 1. Faraday plane lens; 10. Faraday element; 20. Phase delay element; 21. First 1 / 4 wave plate; 22. Second 1 / 4 wave plate; 23. Third 1 / 4 wave plate; 30. CLC volume holographic element; 301. Alignment layer; 302. Cholesteric liquid crystal layer; 31. Left-handed CLC volume holographic film; 32. Right-handed CLC volume holographic film; 4. Photosensitive component; 5. Optical lens; 51. Lens barrel; 52. Curved lens.

[0038] The above description of the main component symbols is combined with the accompanying drawings and specific implementation methods to further illustrate the present application in detail. DETAILED DESCRIPTION

[0039] The following description is used to disclose the utility model so that those skilled in the art can implement the utility model. The preferred embodiments described below are only examples, and those skilled in the art can think of other obvious variations. The basic principles of the utility model defined in the following description can be applied to other embodiments, variations, improvements, equivalents, and other technical solutions that do not deviate from the spirit and scope of the utility model.

[0040] Those skilled in the art should understand that, in the disclosure of the present invention, the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the above terms should not be understood as limiting the present invention.

[0041] In the present invention, the term "one" in the claims and the specification should be understood as "one or more", that is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple. Unless it is clearly indicated in the disclosure of the present invention that the number of the element is only one, the term "one" cannot be understood as unique or single, and the term "one" cannot be understood as a limitation on the quantity.

[0042] In the description of the present utility model, it should be understood that "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In the description of the present utility model, it should be noted that, unless otherwise clearly specified and limited, "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through a medium. For ordinary technicians in this field, the specific meanings of the above terms in the present utility model can be understood according to the specific circumstances.

[0043] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0044] Considering that the light energy utilization rate of the existing folded optical solution is usually less than 25%, VR devices using the existing folded optical solution have to be equipped with higher-power displays, which not only increases power consumption and shortens its battery life, but also significantly increases weight, affecting the user's wearing comfort. Therefore, this application creatively proposes a Faraday plane lens, an optical lens, and an imaging module, which can solve the energy loss of the existing folded optics and achieve a theoretical transmittance of 100%, so as to perfectly replace the application of traditional curved lenses in optical imaging and other scenarios.

[0045] Specifically, refer to the accompanying drawings of the specification of this application. Figures 1 to 9According to an embodiment of the present application, a Faraday plane lens 1 is provided, which may include a Faraday element 10, a pair of phase delay elements 20, and a pair of CLC volume holographic elements 30. The Faraday element 10 is used to rotate the linear polarized light passing through unidirectionally by 45°, and to rotate the linear polarized light passing through bidirectionally by 90°. The two phase delay elements 20 are respectively attached to the opposite two side surfaces of the Faraday element 10, and the fast axis angle between the two phase delay elements 20 is 45°, which is used to convert linear polarized light into circular polarized light. Two CLC volume hologram elements 30 are respectively attached to the outer surfaces of two phase delay elements 20, wherein each CLC volume hologram element 30 comprises an alignment layer 301 for recording lens information and a cholesteric liquid crystal layer 302 which is stacked on the alignment layer 301 and has a periodic spiral structure, and the spiral axis of the cholesteric liquid crystal layer 302 is perpendicular to the light incident surface of the CLC volume hologram element 30, and is used for selectively reflecting circularly polarized light having the same chirality as the CLC volume hologram element 30 to modulate the propagation direction, and selectively transmitting circularly polarized light having the opposite chirality to the CLC volume hologram element 30 to maintain the propagation direction.

[0046] More specifically, the Faraday element 10 mentioned in the present application refers to a nonreciprocal Faraday polarization rotator, that is, when linearly polarized light propagates forward to pass through the nonreciprocal Faraday polarization rotator, the polarization plane of the linearly polarized light rotates 45°; further, when the linearly polarized light is reflected back and propagates backward to pass through the nonreciprocal Faraday polarization rotator, the polarization plane of the linearly polarized light continues to rotate 45° in the same direction; that is, the linearly polarized light rotates 45° when passing through the Faraday element 10 unidirectionally, and rotates 90° when passing through the Faraday element 10 bidirectionally.

[0047] The CLC volume holographic element 30 mentioned in the present application refers to a cholesteric liquid crystal (CLC) equipped with an alignment layer. As a material with strong polarization selectivity, it completely reflects circularly polarized light of a specific rotation direction at an angle that satisfies the Bragg law, and can completely transmit circularly polarized light of another rotation direction. At the same time, the optical properties of the CLC volume holographic element 30 mentioned in the present application are determined by the alignment layer 301. Based on the specific alignment layer design and exposure, it can have an optical focal length similar to that of a lens, and is a planar optical element that can modulate reflected light. It can be understood that the cholesteric liquid crystal layer 302 can be regarded as a one-dimensional Bragg along the spiral axis and a mirror perpendicular to the spiral axis: the Bragg determines the reflection center wavelength, and the mirror determines the reflection imaging law; the reflection imaging law of the cholesteric liquid crystal layer 302 follows that the angles formed by the incident, reflection and the mirror normal are equal, which is the same law followed by the general Fresnel mirror reflection; therefore, the reflection of the CLC volume holographic element 30 of the present application is within its angular reflection bandwidth and is independent of the wavelength; that is, the reflection of the CLC volume holographic element 30 of the present application is achromatic.

[0048] In this way, Figure 2As shown, the circularly polarized light incident from the left side of the Faraday plane lens 1 and having the opposite chirality to the CLC volume hologram element 30 on the left side (i.e., the incident light propagating to the right) first passes through the CLC volume hologram element 30 on the left side to propagate to the right to the phase delay element 20 on the left side, and then is converted into linearly polarized light by the phase delay element 20 on the left side to propagate to the right to the Faraday element 10; then, the linearly polarized light is first rotated by 45° by the Faraday element 10 to propagate to the right to the phase delay element on the right side. 20, and then converted into circularly polarized light having the same chirality as the CLC volume hologram element 30 on the right through the phase delay element 20 on the right to propagate rightward to the CLC volume hologram element 30 on the right; then, the circularly polarized light is first reflected by the CLC volume hologram element 30 on the right to propagate leftward to the phase delay element 20 on the right, and then converted into linearly polarized light through the phase delay element 20 on the right to propagate leftward to the Faraday element 10; then, the linearly polarized light is first reflected by the CLC volume hologram element 30 on the right to propagate leftward to the phase delay element 20 on the right 10 is further rotated by 45° to propagate to the left to the phase delay element 20 on the left, and then converted into circularly polarized light having the same chirality as the CLC volume hologram element 30 on the left by the phase delay element 20 on the left to propagate to the right to the CLC volume hologram element 30 on the left; thereafter, the circularly polarized light is first reflected by the CLC volume hologram element 30 on the left to propagate to the right to the phase delay element 20 on the left, and then converted into linearly polarized light by the phase delay element 20 on the left to propagate to the right The Faraday element 10; then, the linearly polarized light firstly rotates 45° through the Faraday element 10 to propagate rightward to the phase delay element 20 located on the right side, and then is converted into circularly polarized light having the opposite chirality to the CLC volume hologram element 30 located on the right side through the phase delay element 20 located on the right side to propagate rightward to the CLC volume hologram element 30 located on the right side; finally, the circularly polarized light passes through the CLC volume hologram element 30 located on the right side to be emitted from the right side of the Faraday plane lens 1 to form an outgoing light propagating rightward. It can be understood that the present application will Figure 2 The direction from left to right is defined as the positive direction of the Z axis. Figure 2 The direction from bottom to top is defined as the positive direction of the Y axis. Figure 2 The direction from front to back is defined as the positive direction of the X-axis.

[0049] In other words, if Figure 1 and Figure 2 As shown, the Faraday plane lens 1 of the present application forms a folded optical system through a Faraday element 10, a phase delay element 20 and a CLC volume holographic element 30, converting the reflection system into a transmission system so that it is equivalent to a transmission flat optical device as a whole, thereby transmission modulating light to replace the application of traditional curved lenses in optical imaging.

[0050] It is noteworthy that since the Faraday element 10 has almost no energy loss when rotating linearly polarized light, the CLC volume holographic element 30 has almost no energy loss when reflecting or transmitting circularly polarized light, and although the phase delay element 20 has polarization loss when converting circularly polarized light and linearly polarized light, this part of energy loss is extremely small. Therefore, there is almost no energy loss in the process of light propagating in the Faraday plane lens 1, that is, the Faraday plane lens 1 has almost no energy loss while realizing folded optics, and its transmittance can theoretically reach 100%, which is much larger than the 25% of the existing folded optics solution.

[0051] In addition, unlike the traditional volume hologram, the CLC volume hologram element 30 of the present application can record the lens information in the alignment layer 301 by means of double-beam interference, so that the reflection surface of the cholesteric liquid crystal layer 302 is changed from a traditional plane to a curved surface, that is, its reflection surface is not always perpendicular to the spiral axis, but it does not affect the basic law of reflection imaging, which is equivalent to forming a reflection lens for curved surface reflection of circularly polarized light to modulate the propagation direction of the circularly polarized light; in other words, the Faraday plane lens 1 of the present application can superimpose the focusing capabilities of two CLC volume hologram elements to achieve twice the focusing capability.

[0052] According to some examples of the present application, the two CLC volume holographic elements 30 of the present application may have spiral structures with opposite directions of rotation; that is, Figure 3 and Figure 6 As shown, one CLC volume hologram element 30 in the Faraday plane lens 1 is implemented as a left-handed CLC volume hologram film 31 , and the other CLC volume hologram element 30 in the Faraday plane lens 1 is implemented as a right-handed CLC volume hologram film 32 .

[0053] It is worth noting that regarding the chirality of CLC volume holographic materials: the direction of the optical axis (ne) or fast axis (no) in CLC changes layer by layer, similar to a spiral structure. Assume that the spiral axis is vertical, the thumb is parallel to the spiral axis, either upward or downward, and the other four fingers are bent; in this way, if the direction of rotation of the material layer by layer along the direction of the thumb matches the bending direction of the four fingers of the right hand, it is a right-handed CLC volume holographic material, otherwise it is a left-handed CLC volume holographic material. Regarding the handedness (chirality) of circularly polarized light: This application adopts the most common definition: looking towards (not along) the direction of propagation of light, if the electric vector rotates clockwise, or rotates to the right at the 12 o'clock position, it is right-handed circularly polarized light; otherwise it is left-handed circularly polarized light.

[0054] Therefore, according to the above definition, the left-handed CLC volume holographic film 31 mentioned in the present application refers to a CLC volume holographic element with a left-handed spiral structure, which is used to reflect left-handed circularly polarized light (LCP for short) and transmit right-handed circularly polarized light (RCP for short); the right-handed CLC volume holographic film 32 mentioned in the present application refers to a CLC volume holographic element with a right-handed spiral structure, which is used to reflect RCP and transmit LCP.

[0055] Alternatively, if Figure 4 and Figure 5 As shown, the two phase delay elements 20 are implemented as two 1 / 4 wave plates with fast axis angle of 45°; that is, the angle between the fast axes of the two 1 / 4 wave plates in the Faraday plane lens 1 is 45°.

[0056] For example, in the first example of the present application, Figure 3 As shown, the CLC volume hologram element 30 located on the left side of the Faraday plane lens 1 is implemented as a left-handed CLC volume hologram film 31, and the CLC volume hologram element 30 located on the right side of the Faraday plane lens 1 is implemented as a right-handed CLC volume hologram film 32. Figure 4 As shown, the phase delay element 20 on the left side of the Faraday plane lens 1 is implemented as a first quarter wave plate 21 with a fast axis tilted by -45°, and as shown in FIG. Figure 5 As shown, the phase delay element 20 on the right side of the Faraday plane lens 1 is implemented as a second 1 / 4 wave plate 22 with a fast axis arranged vertically. It can be understood that the angle between the fast axis of the first 1 / 4 wave plate 21 mentioned in the present application and the Y axis is -45°; the angle between the fast axis of the second 1 / 4 wave plate 22 mentioned in the present application and the Y axis is 0°.

[0057] Like this: Figure 3As shown, first, the RCP incident from the left side propagates to the right to the first 1 / 4 wave plate 21 after passing through the left-handed CLC volume holographic film 31 to be converted into horizontally polarized linear polarized light (LP for short), and then continues to propagate to the right to the Faraday element 10 to be rotated 45° to form a -45° tilted polarized LP; secondly, the -45° tilted polarized LP first propagates to the right to the second 1 / 4 wave plate 22 to be converted into RCP, and then continues to propagate to the right to the right-handed CLC volume holographic film 32 to be reflected back to the second 1 / 4 wave plate 22 by the curved surface; then, the RCP is first converted into a -45° tilted polarized LP by the second 1 / 4 wave plate 22 to propagate to the left to the Faraday element 10, and then continues to propagate to the right by the Faraday element 10. It continues to rotate 45° to form a vertically polarized LP; then, the vertically polarized LP first propagates to the left to the first 1 / 4 wave plate 21 to be converted into LCP, and then continues to propagate to the left to the left-handed CLC volume holographic film 31 to be reflected back to the first 1 / 4 wave plate 21 by the curved surface; thereafter, the LCP is first converted into a vertically polarized LP by the first 1 / 4 wave plate 21 to propagate to the right to the Faraday element 10, and then continues to rotate 45° by the Faraday element 10 to form a 45° tilted polarized LP; finally, the 45° tilted polarized LP first propagates to the right to the second 1 / 4 wave plate 22 to be converted into LCP, and then continues to propagate to the right to the right-handed CLC volume holographic film 32 to be transmitted out, and there is no energy loss in the entire propagation process.

[0058] Similarly, in the second example of the present application, if Figure 6 As shown, the CLC volume hologram element 30 located on the left side of the Faraday plane lens 1 is implemented as a right-handed CLC volume hologram film 32, and the CLC volume hologram element 30 located on the right side of the Faraday plane lens 1 is implemented as a left-handed CLC volume hologram film 31. At the same time, the phase delay element 20 located on the left side of the Faraday plane lens 1 is still implemented as a first 1 / 4 wave plate 21 with a fast axis tilted at -45°, and the phase delay element 20 located on the right side of the Faraday plane lens 1 is still implemented as a second 1 / 4 wave plate 22 with a fast axis vertically arranged.

[0059] Like this: Figure 6As shown, first, the LCP incident from the left side propagates to the right to the first 1 / 4 wave plate 21 after passing through the right-handed CLC volume holographic film 32 to be converted into a vertically polarized LP, and then continues to propagate to the right to the Faraday element 10 to be rotated 45° to form a 45° tilted polarized LP; secondly, the 45° tilted polarized LP first propagates to the right to the second 1 / 4 wave plate 22 to be converted into LCP, and then continues to propagate to the right to the left-handed CLC volume holographic film 31 to be reflected back to the second 1 / 4 wave plate 22 by the curved surface; then, the LCP is first converted into a 45° tilted polarized LP via the second 1 / 4 wave plate 22 to propagate to the left to the Faraday element 10, and then continues to rotate 45° via the Faraday element 10. To form a horizontally polarized LP; then, the horizontally polarized LP first propagates to the left to the first 1 / 4 wave plate 21 to be converted into RCP, and then continues to propagate to the left to the right-handed CLC volume holographic film 32 to be reflected back to the first 1 / 4 wave plate 21 by the curved surface; thereafter, the RCP is first converted into a horizontally polarized LP by the first 1 / 4 wave plate 21 to propagate to the right to the Faraday element 10, and then continues to rotate 45° by the Faraday element 10 to form a -45° tilted polarized LP; finally, the -45° tilted polarized LP first propagates to the right to the second 1 / 4 wave plate 22 to be converted into RCP, and then continues to propagate to the right to the left-handed CLC volume holographic film 31 to be transmitted out, and there is no energy loss in the entire propagation process.

[0060] It is worth noting that the CLC volume holographic element 30 of the present application also inherits the advantages of the traditional volume holographic: for example, it can record the information of a large-diameter lens so as to achieve a large focusing or diverging ability. It is understandable that the tolerance to the incident angle comes from the optical properties of the cholesteric liquid crystal itself. As long as the cholesteric liquid crystal layer 302 is thick enough, it will not be too sensitive to the incident angle.

[0061] In addition, in other examples of the present application, the two CLC volume holographic elements 30 of the present application may have spiral structures with the same handedness; that is, Figure 7 and Fig. 9 As shown, the two CLC volume holographic elements 30 in the Faraday plane lens 1 can both be implemented as left-handed CLC volume holographic films 31 or right-handed CLC volume holographic films 32, and can still achieve a lossless transmission-type folded light path effect.

[0062] For example, in the third example of the present application, Figure 7 As shown in FIG. 1 , the CLC volume hologram element 30 on the left and the CLC volume hologram element 30 on the right in the Faraday plane lens 1 are both implemented as left-handed CLC volume hologram films 31. Figure 8 As shown, the phase delay element 20 on the left side of the Faraday plane lens 1 is implemented as a third 1 / 4 wave plate 23 with a fast axis tilted 45°, and as shown in FIG. Figure 5 As shown, the phase delay element 20 on the right side of the Faraday plane lens 1 is implemented as a second 1 / 4 wave plate 22 with a fast axis arranged vertically. It can be understood that the angle between the fast axis of the third 1 / 4 wave plate 21 mentioned in the present application and the Y axis is 45°; the angle between the fast axis of the second 1 / 4 wave plate 22 mentioned in the present application and the Y axis is 0°.

[0063] Like this: Figure 7 As shown, first, the RCP incident from the left side propagates to the right to the third 1 / 4 wave plate 23 after passing through the left-handed CLC volume holographic film 31 located on the left side to be converted into a vertically polarized linear polarized light, and then continues to propagate to the right to the Faraday element 10 to be rotated 45° to form a 45° inclined polarized LP; secondly, the 45° inclined polarized LP first propagates to the right to the second 1 / 4 wave plate 22 to be converted into LCP, and then continues to propagate to the right to the left-handed CLC volume holographic film 31 located on the right side to be reflected back to the second 1 / 4 wave plate 22 by the curved surface; then, the LCP is first converted into a 45° inclined polarized LP by the second 1 / 4 wave plate 22 to propagate to the left to the Faraday element 10, and then continues to rotate 45° by the Faraday element 10. ° to form a horizontally polarized LP; then, the horizontally polarized LP first propagates to the left to the third 1 / 4 wave plate 23 to be converted into LCP, and then continues to propagate to the left to the left-handed CLC volume holographic film 31 located on the left to be reflected back to the third 1 / 4 wave plate 23 by the curved surface; thereafter, the LCP is first converted into a horizontally polarized LP by the third 1 / 4 wave plate 23 to propagate to the right to the Faraday element 10, and then continues to rotate 45° by the Faraday element 10 to form a -45° tilted polarized LP; finally, the -45° tilted polarized LP first propagates to the right to the second 1 / 4 wave plate 22 to be converted into RCP, and then continues to propagate to the right to the left-handed CLC volume holographic film 31 located on the right to be transmitted out, and there is no energy loss in the entire propagation process.

[0064] Similarly, in the fourth example of the present application, if Fig. 9 As shown in FIG. 1 , the CLC volume hologram element 30 on the left and the CLC volume hologram element 30 on the right in the Faraday plane lens 1 are both implemented as right-handed CLC volume hologram films 32. Figure 8 As shown, the phase delay element 20 on the left side of the Faraday plane lens 1 is implemented as a third 1 / 4 wave plate 23 with a fast axis tilted 45°, and as shown in FIG. Figure 5 As shown, the phase delay element 20 located on the right side of the Faraday plane lens 1 is implemented as a second 1 / 4 wave plate 22 with a fast axis arranged vertically.

[0065] Like this: Fig. 9As shown, first, the LCP incident from the left side propagates to the right to the third 1 / 4 wave plate 23 after passing through the right-handed CLC volume holographic film 32 located on the left side to be converted into horizontally polarized linear polarized light, and then continues to propagate to the right to the Faraday element 10 to be rotated 45° to form a -45° tilted polarized LP; secondly, the -45° tilted polarized LP first propagates to the right to the second 1 / 4 wave plate 22 to be converted into RCP, and then continues to propagate to the right to the right-handed CLC volume holographic film 32 located on the right side to be reflected back to the second 1 / 4 wave plate 22 by the curved surface; then, the RCP is first converted into a -45° tilted polarized LP by the second 1 / 4 wave plate 22 to propagate to the left to the Faraday element 10, and then continues to rotate by the Faraday element 10 45° to form a vertically polarized LP; then, the vertically polarized LP first propagates to the left to the third 1 / 4 wave plate 23 to be converted into RCP, and then continues to propagate to the left to the right-handed CLC volume holographic film 32 located on the left to be reflected back to the third 1 / 4 wave plate 23 by the curved surface; thereafter, the RCP is first converted into a vertically polarized LP by the third 1 / 4 wave plate 23 to propagate to the right to the Faraday element 10, and then continues to rotate 45° by the Faraday element 10 to form a 45° tilted polarized LP; finally, the 45° tilted polarized LP first propagates to the right to the second 1 / 4 wave plate 22 to be converted into LCP, and then continues to propagate to the right to the right-handed CLC volume holographic film 32 located on the right to be transmitted out, and there is no energy loss in the entire propagation process.

[0066] It is worth noting that in other examples of the present application, the two phase delay elements 20 in the Faraday plane lens 1 can also be implemented as 1 / 4 wave plates with fast axes arranged at other angles, as long as the fast axis angle of the two 1 / 4 wave plates is ensured to be 45°, and this application will not go into details.

[0067] In addition, unlike the existing folded optical solution (Pancake solution), Figure 1 and Figure 2 As shown, the Faraday plane lens 1 of the present application is formed by stacking and bonding a Faraday element 10, two phase delay elements 20 and two CLC volume holographic elements 30 together, with no air gap between them, so as to present a complete plane lens as a whole, so as to perfectly replace the application of traditional curved lenses in optical imaging.

[0068] According to another aspect of the present application, Fig.10 As shown, an embodiment of the present application further provides an imaging module, which may include a photosensitive component 4 and an optical lens 5 having the above-mentioned Faraday plane lens 1, and the optical lens 5 is located on the photosensitive side of the photosensitive component 4 so that the Faraday plane lens 1 can be used to replace the traditional lens to achieve high-quality and clean white light imaging.

[0069] Specifically, Fig.10 As shown, the optical lens 5 may include a lens barrel 51 and a Faraday plane lens 1 assembled in the lens barrel 51, and the lens barrel 51 is fixedly connected to the photosensitive component 4 to keep the Faraday plane lens 1 in the photosensitive path of the photosensitive component 4, so that the light is first modulated by the Faraday plane lens 1 and then received by the photosensitive component 4 to form an image.

[0070] It is worth noting that the lens groups in the optical lens 5 mentioned in the present application can all be implemented as the Faraday plane lens 1, or can be composed of the Faraday plane lens 1 and a traditional curved lens 52. For example, Fig.10 As shown, the optical lens 5 may further include a curved lens 52 , and the curved lens 52 is coaxially arranged with the Faraday plane lens 1 .

[0071] It is worth mentioning that according to another aspect of the present application, Fig.11 As shown, an embodiment of the present application further provides a method for manufacturing a Faraday plane lens, which may include the steps of:

[0072] S110: providing a Faraday element for rotating the linear polarized light passing through unidirectionally by 45° and rotating the linear polarized light passing through bidirectionally by 90°;

[0073] S120: attaching a pair of phase delay elements to the two opposite side surfaces of the Faraday element respectively, so that the fast axis angle between the two phase delay elements is 45°; and

[0074] S130: A pair of CLC volume hologram elements are respectively disposed on the outer surfaces of two phase delay elements, wherein the CLC volume hologram element has an alignment layer for recording lens information and a cholesteric liquid crystal layer stacked on the alignment layer and having a periodic spiral structure, and the spiral axis of the cholesteric liquid crystal layer is perpendicular to the light incident surface of the CLC volume hologram element.

[0075] For example, Fig.12 As shown, step S130 in the method for manufacturing the Faraday plane lens may include the following steps:

[0076] S131: coating a liquid crystal alignment material on the outer surfaces of two phase delay elements respectively;

[0077] S132: exposing the liquid crystal alignment material through a double-beam interference exposure process to form an alignment layer for recording lens information in the form of an alignment direction; and

[0078] S133: coating a cholesteric liquid crystal material on the alignment layer to form the cholesteric liquid crystal layer.

[0079] It can be understood that the liquid crystal molecules in the cholesteric liquid crystal material coated on the alignment layer will follow the alignment recorded in the alignment layer to change the alignment of the liquid crystal molecules point by point on the alignment layer; at the same time, the recorded lens information will be transmitted layer by layer along the thickness direction of the cholesteric liquid crystal layer to have the focal length of reflected light.

[0080] It is worth noting that, although in the above examples of the present application, the alignment layer of the CLC volume hologram element is directly formed on the outer surface of the phase delay element so that the cholesteric liquid crystal layer is located at the outermost side; however, in other examples of the present application, the liquid crystal alignment material may also be first coated on a transparent substrate to form an alignment layer, and then the cholesteric liquid crystal material may be coated on the alignment layer to prepare the CLC volume hologram element; and then the cholesteric liquid crystal layer of the CLC volume hologram element is adhered to the outer surface of the phase delay element, and the transparent substrate is removed so that the alignment layer is located at the outermost side, which will not be described in detail in the present application.

[0081] It is worth mentioning that according to another aspect of the present application, Fig.13A and Fig. 13B As shown, an embodiment of the present application further provides a Faraday imaging method, which may include the steps of:

[0082] S21: transmitting the circularly polarized light having the opposite chirality to the CLC volume hologram element on the left through the CLC volume hologram element on the left to propagate rightward to the phase delay element on the left;

[0083] S22: converting the circularly polarized light into linearly polarized light through the phase delay element located on the left side so as to propagate rightward to the Faraday element;

[0084] S23: rotating the polarization plane of the linearly polarized light by 45° through the Faraday element so as to propagate rightward to the phase delay element located on the right side;

[0085] S24: converting the linearly polarized light rotated by 45° into circularly polarized light having the same chirality as the CLC volume hologram element on the right through the phase delay element on the right, so as to propagate rightward to the CLC volume hologram element on the right;

[0086] S25: Through the CLC volume hologram element located on the right, the curved surface reflects the circularly polarized light to propagate leftward to the phase delay element located on the right;

[0087] S26: converting the reflected circularly polarized light into the linearly polarized light rotated by 45° through the phase delay element located on the right side so as to propagate to the left to the Faraday element;

[0088] S27: The linearly polarized light rotated by 45° is further rotated by 45° through the Faraday element so as to propagate leftward to the phase delay element located on the left side;

[0089] S28: converting the linearly polarized light rotated by 90° into circularly polarized light having the same chirality as the CLC volume hologram element on the left through the phase delay element on the left, so as to propagate leftward to the CLC volume hologram element on the left;

[0090] S29: Through the CLC volume hologram element located on the left, the curved surface reflects the circularly polarized light to propagate rightward to the phase delay element located on the left;

[0091] S30: converting the reflected circularly polarized light into the linearly polarized light rotated by 90° through the phase delay element on the left side so as to propagate rightward to the Faraday element;

[0092] S31: The linearly polarized light rotated by 90° is further rotated by 45° through the Faraday element so as to propagate rightward to the phase delay element located on the right side;

[0093] S32: converting the linearly polarized light rotated by 135° into circularly polarized light having a chirality opposite to that of the CLC volume hologram element on the right through the phase delay element on the right so as to propagate rightward to the CLC volume hologram element on the right; and

[0094] S33: The circularly polarized light is transmitted through the CLC volume hologram element located on the right side to form an image.

[0095] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0096] The above embodiments only express several implementation methods of the utility model, and the descriptions are relatively specific and detailed, but they cannot be understood as limiting the scope of the utility model patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the utility model, which all belong to the protection scope of the utility model.

Claims

1. A Faraday plane lens, characterized in that: include: A Faraday element is used to rotate linear polarized light passing through one direction by 45° and to rotate linear polarized light passing through two directions by 90°; A pair of phase delay elements, wherein the two phase delay elements are respectively attached to the opposite side surfaces of the Faraday element, and the fast axis angle between the two phase delay elements is 45°, and are used for converting linear polarized light into circular polarized light; and A pair of CLC volume hologram elements, the two CLC volume hologram elements are respectively and correspondingly attached to the outer surfaces of the two phase delay elements, wherein each of the CLC volume hologram elements has an alignment layer for recording lens information and a cholesteric liquid crystal layer stacked on the alignment layer and having a periodic spiral structure, and the spiral axis of the cholesteric liquid crystal layer is perpendicular to the light incident surface of the CLC volume hologram element, and is used for selectively reflecting circularly polarized light with the same chirality as the CLC volume hologram element to modulate the propagation direction, and selectively transmitting circularly polarized light with an opposite chirality to the CLC volume hologram element to maintain the propagation direction.

2. The Faraday plane lens according to claim 1, characterized in that: The Faraday element is a non-reciprocal Faraday polarization rotator.

3. The Faraday plane lens according to claim 1, characterized in that: The phase delay element is a 1 / 4 wave plate.

4. The Faraday plane lens according to any one of claims 1 to 3, characterized in that: The two CLC volume holographic elements have helical structures with opposite handedness.

5. The Faraday plane lens according to claim 4, characterized in that: The two CLC volume holographic elements are respectively a left-handed CLC volume holographic film and a right-handed CLC volume holographic film; the phase delay element on the left is a first 1 / 4 wave plate arranged with a fast axis tilted at -45°, and the phase delay element on the right is a second 1 / 4 wave plate arranged with a fast axis vertically.

6. The Faraday plane lens according to any one of claims 1 to 3, characterized in that: The two CLC volume holographic elements have spiral structures with the same handedness.

7. The Faraday plane lens according to claim 6, characterized in that: The two CLC volume holographic elements are both left-handed CLC volume holographic films or right-handed CLC volume holographic films; the phase delay element on the left is the third 1 / 4 wave plate with the fast axis tilted 45°, and the phase delay element on the right is the second 1 / 4 wave plate with the fast axis vertically arranged.

8. An optical lens, characterized in that: include: Lens tube; The Faraday plane lens according to any one of claims 1 to 7, wherein the Faraday plane lens is assembled in the lens barrel.

9. The optical lens according to claim 8, characterized in that: It further includes a curved lens, which is coaxially arranged with the Faraday plane lens.

10. An imaging module, characterized in that: include: Photosensitive components; and The optical lens as described in claim 8 or 9, wherein the optical lens is arranged on the photosensitive side of the photosensitive component.

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