Optical imaging system and imaging apparatus

Abstract

The embodiment of the present application relates to the field of optical imaging, and discloses an optical imaging system and an imaging device.The optical imaging system comprises a first light splitting element, a first optical phase modulation element and a second light splitting element arranged in sequence according to the transmission direction of the light rays emitted by the object to be imaged.The incident light rays of the first light splitting element are polarized light of a first polarization direction, the first light splitting element transmits the polarized light of the first polarization direction and reflects the polarized light of a second polarization direction, and the first polarization direction is orthogonal to the second polarization direction.The first optical phase modulation element is a quarter-wave plate.The second light splitting element reflects part of the light rays emitted by the first optical phase modulation element and transmits another part of the light rays emitted by the first optical phase modulation element.Such an arrangement does not need to tilt any optical element, so that the space occupied by each optical element is smaller, thereby reducing the volume of the imaging device.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of optical technology, and more particularly to an optical imaging system and an imaging device. Background Art

[0002] A real image is one that can be displayed on a screen. In practice, a real image can be displayed either on a screen or suspended in mid-air. The principle of a real image is that light rays emitted by the object being imaged are reflected or refracted, causing them to converge. The image formed by this convergence is the real image of the object being imaged.

[0003] like Figure 1 As shown, a conventional real image imaging device includes a display source 11, a reflective polarizing element 12, a retroreflective element 13 and a wave plate 14, wherein the reflective polarizing element 12 receives the light emitted by the display source 11, and then transmits part of the light to the other side of the reflective polarizing element 12, and reflects the other part of the light to the wave plate 14. The wave plate 14 processes the received light and emits it to the retroreflective element 13. The retroreflective element 13 retroreflects the received light, so that the retroreflected light is transmitted through the wave plate 14 and the reflective polarizing element 12, and then converges on the other side of the reflective polarizing element 12 to form a real image of the object displayed by the display source 11.

[0004] It can be seen that in order to ensure that the light emitted by the display source 11 can be converged to form an image, the reflective polarizing element 12 should maintain a certain angle with both the display source 11 and the retroreflective element 13. In other words, the reflective polarizing element 12 should be placed at an angle relative to the other elements. However, the tilted placement of the reflective polarizing element 12 requires a larger space, which results in a relatively large volume of the real image forming device. Summary of the Invention

[0005] Embodiments of the present invention provide an optical imaging system and an imaging device, which can solve the problem of relatively large volume of existing imaging devices.

[0006] In a first aspect, an embodiment of the present invention provides an optical imaging system, comprising:

[0007] A first beam splitting element, a first optical phase modulation element, and a second beam splitting element are sequentially arranged according to the transmission direction of the light emitted by the object to be imaged;

[0008] The incident light of the first beam splitter is polarized light in a first polarization direction, the first beam splitter transmits the polarized light in the first polarization direction and reflects the polarized light in a second polarization direction, the first polarization direction being orthogonal to the second polarization direction;

[0009] The first optical phase modulation element is a quarter wave plate;

[0010] The second light splitting element reflects part of the light emitted by the first optical phase modulation element and transmits another part of the light emitted by the first optical phase modulation element.

[0011] In some possible implementation manners, at least one of the first light splitting element and the second light splitting element converges the light, so that the second light splitting element converges the light reflected by the first light splitting element after emitting the light; or the second light splitting element diverges the light.

[0012] In some possible implementation manners, the first light splitting element comprises a planar element and a curved element.

[0013] When the first light splitting element is the curved element, a concave surface of the first light splitting element faces the first optical phase modulation element, or a convex surface of the first light splitting element faces the first optical phase modulation element.

[0014] In some possible implementation manners, if at least one of the first light splitting element and the second light splitting element converges the light, when a concave surface of the first light splitting element faces the first optical phase modulation element, the second light splitting element is a planar element, an element with a convex surface facing the first optical phase modulation element, or an element with a concave surface facing the first optical phase modulation element,

[0015] When the second light splitting element is an element with a convex surface facing the first optical phase modulation element, a curvature of the first light splitting element is greater than a curvature of the second light splitting element.

[0016] When the first light splitting element is the planar element or an element with a convex surface facing the first optical phase modulation element, the second light splitting element is an element with a concave surface facing the first optical phase modulation element, and a curvature of the second light splitting element is greater than a curvature of the first light splitting element.

[0017] In some possible implementation manners, a reflectivity of the second light splitting element to light satisfies 10% to 90%, or a transmissivity of the second light splitting element to light satisfies 10% to 90%.

[0018] In some possible implementation manners, the optical imaging system further comprises a second optical phase modulation element and a polaroid arranged in sequence according to a transmission emission direction of the second light splitting element.

[0019] The second optical phase modulation element is a quarter-wave plate, and an optical axis of the second optical phase modulation element and an optical axis of the first optical phase modulation element form an angle of 0°, 180°, 90° or -90°.

[0020] The polarizing sheet has an absorbing axis and a transmitting axis, and the angle between the transmitting axis of the polarizing sheet and the optical axis of the second optical phase modulation element is 45°, -45°, 135° or -135°.

[0021] In some possible embodiments, when the angle between the optical axis of the second optical phase modulation element and the optical axis of the first optical phase modulation element is 0° or 180°, the polarizing sheet transmits polarized light of the first polarization direction.

[0022] When the angle between the optical axis of the second optical phase modulation element and the optical axis of the first optical phase modulation element is 90° or -90°, the polarizing sheet transmits polarized light of the second polarization direction.

[0023] In the second aspect, the embodiments of the present application provide an imaging device, comprising a display element and an optical imaging system, the display element is used to emit light of an object to be imaged, the light is polarized light of a first polarization direction, and the optical imaging system is as described in the first aspect or any possible implementation manner of the first aspect.

[0024] In some possible embodiments, the display element is implemented as any of the following:

[0025] The object to be imaged is irradiated by linearly polarized light, the object to be imaged emits linearly polarized light, a display displays an image of the object to be imaged, the display emits linearly polarized light, or the display is combined with a linearly polarized light processing device to emit linearly polarized light.

[0026] In some possible embodiments, when the imaging device forms a real image, the distance from the light emitting surface of the display element to the imaging plane of the real image is greater than or equal to the distance from the light emitting surface to the second light splitting element.

[0027] In order to solve the problem of relatively large volume of existing imaging devices, the optical imaging system provided in an embodiment of the present application includes a first spectroscopic element, a first optical phase modulation element, and a second spectroscopic element arranged in sequence according to the transmission direction of the light emitted by the object to be imaged, wherein the first optical phase modulation element is a quarter wave plate. For the light incident on the first optical phase modulation element, the second spectroscopic element reflects part of the incident light and transmits another part of the incident light. The first spectroscopic element transmits the light emitted by the object to be imaged and reflects the light from the second spectroscopic element and passing through the first optical phase modulation element. In this way, if the light emitted by the object to be imaged is polarized light in the first polarization direction, then the first spectroscopic element transmits the polarized light in the first polarization direction. Furthermore, the light emitted by the first spectroscopic element is phase-modulated for the first time by the first optical phase modulation element and then enters the second spectroscopic element, and the light reflected by the second spectroscopic element passes through the first optical phase modulation element again and enters the first spectroscopic element. At this time, the polarized light in the first polarization direction passes through the first optical phase modulation element twice, resulting in a phase delay of π, that is, the polarization direction of the light is rotated 90°, that is, the light incident on the first beam splitter element is polarized light in the second polarization direction, and the first beam splitter element reflects the polarized light in the second polarization direction. The light reflected by the first beam splitter element passes through the first optical phase modulation element and the second beam splitter element, thereby enabling the transmitted light to be imaged. It can be seen that the optical imaging system provided in the embodiment of the present application utilizes the polarization of light to still achieve reflection and transmission of light and ultimately imaging between the sequentially arranged optical elements, without the need to tilt any optical element, so that the space occupied by each optical element is smaller, thereby reducing the volume of the imaging device. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0029] Figure 1 is a schematic structural diagram of an exemplary conventional real image forming apparatus provided in an embodiment of the present application;

[0030] Figure 2 is a schematic diagram of light transformation of an exemplary optical phase modulation provided in an embodiment of the present application;

[0031] Figure 3A is a schematic diagram of an exemplary structure of an optical imaging system 30 provided in an embodiment of the present application;

[0032] Figure 3B is a schematic diagram of an exemplary structure of an optical imaging system 300 provided in an embodiment of the present application;

[0033] Figure 3C FIG. 7 is an exemplary structural schematic diagram of an optical imaging system 3000 provided by an embodiment of the present application;

[0034] Figure 4A FIG. 8 is an exemplary structural schematic diagram of an optical imaging system 41 provided by an embodiment of the present application;

[0035] Figure 4B FIG. 9 is an exemplary structural schematic diagram of an optical imaging system 42 provided by an embodiment of the present application;

[0036] Figure 4C FIG. 10 is an exemplary structural schematic diagram of an optical imaging system 43 provided by an embodiment of the present application;

[0037] Figure 5 FIG. 11 is a structural schematic diagram of an imaging device 50 provided by an embodiment of the present application. DETAILED DESCRIPTION

[0038] The terms used in the following embodiments of the present application are for the purpose of describing optional embodiments, and are not intended to be limiting of the present application. As used in the specification and the appended claims of the present application, the singular forms "a," "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that the terms "comprising," "including," "having" and "with" as used herein are specifically intended to be read as open-ended terms of art. The use of such terms in the specification and claims should not be interpreted as indicating that any unclaimed product not expressly recited in the specification and claims is intended to be part of the patent coverage.

[0039] The technologies involved in the embodiments of the present application are explained below.

[0040] Polarized light, also known as polarized light, is a kind of electromagnetic wave, so the light wave transmits in a certain vibration direction during transmission. The plane formed during the transmission of the light wave is called the vibration plane. Generally, the vibration plane of the light wave is in one direction, for example, perpendicular to the ground direction (hereinafter referred to as the vertical direction) or parallel to the ground direction (hereinafter referred to as the horizontal direction), so such light wave is called plane polarized light or linear polarized light.

[0041] Hereinafter, the vertical direction and the horizontal direction are referred to as the first polarization direction and the second polarization direction respectively. In actual implementation, if the vertical direction is the first polarization direction, then the horizontal direction is the second polarization direction, or if the horizontal direction is the first polarization direction, then the vertical direction is the second polarization direction, which is not limited by the embodiments of the present application.

[0042] Optical phase modulation refers to a modulation mode of changing the phase of light by changing the optical path of light. An optical phase modulation element is usually referred to as a wave plate, and the wave plate includes an optical axis parallel to the end face of the wave plate. When linearly polarized light is incident on the wave plate, the wave plate can decompose the incident linearly polarized light into first light perpendicular to the optical axis and second light parallel to the optical axis, and the transmission speed directions of the first light and the second light are the same, but the transmission speeds are different. Based on this, a certain amount of phase difference is generated between the first light and the second light after modulation by the wave plate, thereby realizing phase modulation of the polarized light. The wave plate usually includes a half-wave plate and a quarter-wave plate. The half-wave plate can make the above-mentioned first light and second light generate a phase difference of π, so that the polarization direction of the modulated polarized light is phase-rotated by 90° relative to the polarization direction of the polarized light before modulation. The quarter-wave plate can make the above-mentioned first light and second light generate a phase difference of π / 2, so that the polarization direction of the modulated polarized light is phase-rotated by 45° relative to the polarization direction of the polarized light before modulation.

[0043] The angle between the optical axis of the quarter-wave plate and the polarization direction of the incident polarized light can be +45°, -45°, +135° or -135°. As shown in Figure 2 , the polarized light of the first polarization direction or the second polarization direction can be modulated by the quarter-wave plate to emit circularly polarized light.

[0044] Splitting light refers to splitting one incident light into at least two. The splitting method can include emitting a part of the incident light, and performing other processing on another part of the incident light, the other processing including reflection or absorption, etc. Alternatively, the splitting device only transmits one type of light, and reflects or absorbs other types of light.

[0045] Embodiments of the present application provide an optical imaging system. The optical imaging system sequentially arranges each optical element according to the transmission direction of the light emitted by the object to be imaged. By utilizing the polarization characteristics of light, the sequentially arranged optical elements in the embodiments of the present application can still achieve reflection and transmission of light, thereby causing the light emitted by the optical imaging system to form a real image or a virtual image of the object to be imaged. Any optical element does not need to be placed obliquely, so that the space occupied by each optical element is small, thereby reducing the volume of the corresponding imaging device.

[0046] The technical solutions of the embodiments of the present application will be described below in conjunction with examples.

[0047] Referring to Figure 3A , Figure 3A An optical imaging system 30 (hereinafter referred to as system 30) according to an embodiment of the present application is shown. The system 30 is used for imaging, and includes a first light splitting element 31, a first optical phase modulation element 32 and a second light splitting element 33 sequentially arranged according to the transmission direction of the light emitted by the object to be imaged.

[0048] It can be understood that, Figure 3A The illustrated structure does not constitute a specific limitation to the optical imaging system 30. In other embodiments of the present application, the optical imaging system 30 can include more or fewer optical elements than illustrated (e.g. Figure 3B The illustrated embodiment shows), or different combinations or different arrangements of various optical elements.

[0049] In some embodiments, the incident light ray S1 of the first light splitting element 31 can be polarized light of a first polarization direction, and the first light splitting element 31 transmits the polarized light of the first polarization direction and reflects the polarized light of a second polarization direction. The first polarization direction and the second polarization direction are set as described above. The first optical phase modulation element 32 is a quarter-wave plate. The second light splitting element 33 reflects part of the light ray emitted by the first optical phase modulation element 32 and transmits another part of the light ray emitted by the first optical phase modulation element 32.

[0050] For example, the polarized light S1 of the first polarization direction incident on the first light splitting element 31 is transmitted by the first light splitting element 31 and then incident on the first optical phase modulation element 32. The polarized light S1 is modulated in phase by the first optical phase modulation element 32 to obtain the light ray S2. After the light ray S2 is incident on the second light splitting element 33, part of the light ray S2-1 is reflected by the second light splitting element 33 to the first optical phase modulation element 32, and another part of the light ray is transmitted by the second light splitting element 33 and emitted. The light ray S2-1 is modulated in phase by the first optical phase modulation element 32 to obtain the light ray S3, and the light ray S3 is incident on the first light splitting element 31. Among them, the light ray S3 is modulated twice in phase by the first optical phase modulation element 32 relative to the light ray S1, and the first optical phase modulation element 32 is a quarter-wave plate. Correspondingly, the light ray S3 is delayed by π phase relative to the light ray S1, that is, the polarization direction of S3 is converted by 90° relative to the polarization direction of S1, then the light ray S3 is polarized light of the second polarization direction. Further, the first light splitting element 31 reflects the light ray S3 to the first optical phase modulation element 32. The first optical phase modulation element 32 modulates the phase of the light ray S3 to obtain the light ray S4. After the light ray S4 is incident on the second light splitting element 33, part of the light ray S4-1 is transmitted and emitted, and another part of the light ray is reflected by the second light splitting element 33 to the first optical phase modulation element 32 (not shown in the figure). Figure 3A The light ray S4-1 transmitted and emitted by the second light splitting element 33 is used for imaging. The light ray reflected by the second light splitting element 33 from the light ray S4 is modulated by the first optical phase modulation element 32 to obtain a light ray that is delayed by π phase relative to the light ray S3, which is polarized light of the first polarization direction. After the light ray is incident on the first light splitting element 31, it is transmitted by the first light splitting element 31 and emitted.

[0051] It should be noted that theoretically, the sum of the proportion of the light reflected by the second light splitting element 33 and the proportion of the light transmitted by the second light splitting element 33 should be 100%, and based on this, the reflectivity of the second light splitting element 33 to the light satisfies: 10% to 90%, or the transmissivity of the second light splitting element 33 to the light satisfies: 10% to 90%. It should be understood that when the reflectivity of the second light splitting element 33 to the light is 10%, the transmissivity of the second light splitting element 33 to the light should be 90%. Alternatively, the reflectivity of the second light splitting element 33 to the light can generally be set to 30% to 70%, or the transmissivity of the second light splitting element 33 to the light can be set to 30% to 70%.

[0052] It can be seen that by using the polarization of light, the reflection and transmission of light can still be realized between the sequentially arranged optical elements, and no optical element needs to be placed obliquely, so that the space occupied by each optical element is small, thereby the volume of the imaging device can be reduced, and the user's use experience can be improved.

[0053] It should be understood that Figure 3A The optical imaging system of the embodiment of the present application is only an exemplary description of the present application, and in other implementations, the optical imaging system of the embodiment of the present application can also include more optical elements than the system 30.

[0054] As Figure 3B indicated, Figure 3B An optical imaging system 300 (hereinafter referred to as system 300) of an embodiment of the present application is shown, and the system 300 includes: a first light splitting element 301, a first optical phase modulation element 302, a second light splitting element 303, a second optical phase modulation element 304 and a polaroid 305 sequentially arranged in the transmission direction of the light rays emitted by the object to be imaged. Among them, the function of the first light splitting element 301 refers to the function of the first light splitting element 31 in Figure 3A , the function of the first optical phase modulation element 302 refers to the function of the first optical phase modulation element 32 in Figure 3A , the function of the second light splitting element 303 refers to the function of the second light splitting element 33 in Figure 3A , and the details are not described here.

[0055] The second optical phase modulation element 304 is a quarter-wave plate, and the optical axis of the second optical phase modulation element 304 and the optical axis of the first optical phase modulation element 302 form an angle of 0°, 180°, 90° or -90°, and specifically, it can be flexibly set according to the actual implementation scene. The polaroid 305 splits light by transmitting one polarization direction polarized light and absorbing another polarization direction polarized light, and based on this, the polaroid 305 exists, for example, an absorbing axis and a transmitting axis, and the transmitting axis of the polaroid 305 and the optical axis of the second optical phase modulation element 304 form an angle of 45°, -45°, 135° or -135°, and specifically, it can be flexibly set according to the actual implementation scene.

[0056] In the system 300, the optical path between the object to be imaged and each optical device in the second light splitting element 303 can refer to the description in the system 30, which will not be described in detail here. In the actual implementation scenario, the polarized light transmitted by the polarizer 305 can be polarized light of the first polarization direction, or can be polarized light of the second polarization direction. The polarization direction of the polarized light transmitted by the polarizer 305 is determined according to the relationship between the optical axis of the first optical phase modulation element 302 and the optical axis of the second optical phase modulation element 304.

[0057] Taking the light emitted by the second light splitting element 303 in the system 300 as an example, the part of the light ray S2 and the light ray S4-1 are transmitted, the part of the light ray S2 is modulated by the second optical phase modulation element 304 to emit the light ray S2a, and the light ray S4-1 is modulated by the second optical phase modulation element 304 to emit the light ray S5.

[0058] In some embodiments, if the optical axis of the second optical phase modulation element 304 and the optical axis of the first optical phase modulation element 302 form an angle of 0° or 180°, for example, the optical axis of the first optical phase modulation element 302 and the first polarization direction can form an angle of -45°, and the optical axis of the second optical phase modulation element 304 and the first polarization direction can form an angle of 135°; for another example, the optical axis of the first optical phase modulation element 302 and the first polarization direction can form an angle of 135°, and the optical axis of the second optical phase modulation element 304 and the first polarization direction can form an angle of -45°, which will not be exemplified one by one here. The polarization direction of the light ray S2a is the same as the polarization direction of the light ray S1, which is polarized light of the first polarization direction. Similarly, the polarization direction of the light ray S5 is the same as the polarization direction of the light ray S3, which is polarized light of the second polarization direction. The polarizer 305 is arranged to transmit polarized light of the second polarization direction and absorb polarized light of the first polarization direction.

[0059] In other embodiments, if the angle between the optical axis of the second optical phase modulation element 304 and the optical axis of the first optical phase modulation element 302 is 90° or -90°, for example, the angle between the optical axis of the first optical phase modulation element 302 and the first polarization direction may also be -45°, and the angle between the optical axis of the second optical phase modulation element 304 and the first polarization direction may be -135°. For another example, if the angle between the optical axis of the first optical phase modulation element 302 and the first polarization direction is -135°, and the angle between the optical axis of the second optical phase modulation element 304 and the first polarization direction may be -45°, and examples are not given here one by one. The polarization direction of light S2a is orthogonal to the polarization direction of light S1, and light S2a is polarized light of the second polarization direction. Similarly, the polarization direction of light S5 is orthogonal to the polarization direction of light S3, and light S5 is polarized light of the first polarization direction. The polarizer 305 is configured to transmit polarized light of the first polarization direction and absorb polarized light of the second polarization direction.

[0060] It can be seen that by adopting the embodiment shown in system 300, by arranging the second optical phase modulation element and the polarizer in the transmission output direction of the second beam splitter element, part of the interfering light transmitted by the second beam splitter element can be filtered, thereby optimizing the imaging quality.

[0061] In some embodiments, the optical imaging system described in the embodiments of the present application is used to form a real image. The principle of forming a real image is that the light emitted by the optical imaging system converges to form an image (such as Figure 3A 、 Figure 3B 、 Figures 4A to 4C Based on this, if the optical imaging system described in the embodiment of the present application is used to form a real image, Figure 3A At least one of the first beam splitter element 31 and the second beam splitter element 33 has a converging effect on light, so that the second beam splitter element 33 has a converging effect on the light reflected by the first beam splitter element 31 after being emitted. In other embodiments, the optical imaging system described in the embodiments of the present application is used to form a virtual image, such as Figure 3C The optical imaging system 3000 is shown. Figure 3C The principle of virtual image formation is that the light emitted by the optical imaging system diverges, and the reverse extensions of the diverging light converge to form a virtual image of the object to be imaged. Based on this, if the optical imaging system described in the embodiment of the present application is used to form a virtual image, the light emitted by the second beam splitter element diverges.

[0062] The following describes possible examples of the optical imaging system 30 by taking the optical imaging system used to form a real image as an example.

[0063] In actual implementation scenarios, the first light splitting element 31 in the optical imaging system 30 can include a planar element and a curved element. When the first light splitting element 31 is a curved element, the concave surface of the first light splitting element 31 faces the first optical phase modulation element 32, as shown in a first polarizing beam splitter shown in Figure 4A and Figure 4B or the convex surface of the first light splitting element 31 faces the first optical phase modulation element 32, as shown in a first polarizing beam splitter shown in Figure 4C .

[0064] Optionally, regardless of whether the first light splitting element 31 is a planar element or a curved element, the surface types of the two end surfaces of the first light splitting element 31 can be the same or substantially the same.

[0065] In scenarios in which the optical imaging system forms a real image, in order to ensure that the second light splitting element 33 has a converging effect after the light reflected by the first light splitting element exits, in some embodiments, when the concave surface of the first light splitting element 31 faces the first optical phase modulation element 32, the second light splitting element 33 is a planar element (as shown in Figure 4A ), an element with a convex surface facing the first optical phase modulation element 32 (as shown in Figure 4B ), or an element with a concave surface facing the first optical phase modulation element 32. When the second light splitting element 33 is an element with a convex surface facing the first optical phase modulation element 32, the curvature of the first light splitting element 31 is greater than the curvature of the second light splitting element 33. In other embodiments, when the first light splitting element 31 is a planar element or an element with a convex surface facing the first optical phase modulation element 32, the second light splitting element 33 is an element with a concave surface facing the first optical phase modulation element 32, and the curvature of the second light splitting element 33 is greater than the curvature of the first light splitting element 31, as shown in Figure 4C .

[0066] Optionally, regardless of whether the second light splitting element 33 is a planar element or a curved element, the surface types of the two end surfaces of the second light splitting element 33 can be the same or substantially the same.

[0067] The optical imaging system according to the embodiments of the present application is described below through several exemplary optical imaging systems that form real images.

[0068] As shown in Figure 4A , Figure 4AAn optical imaging system 41 (hereinafter referred to as system 41) is illustrated. In this example, the first light splitting element 31 is implemented as a polarization beam splitter, the first optical phase modulation element 32 is implemented as a quarter wave plate, and the second light splitting element 33 is implemented as a beam splitter. Accordingly, the system 41 includes, in sequence along a transmission direction of the incident light O1, a polarization beam splitter 411, a wave plate 412, and a beam splitter 413. The polarization beam splitter 411 is a curved mirror with a concave surface facing the wave plate 412, and the beam splitter 413 is a flat mirror. In an example, the reflectivity and the transmissivity of the beam splitter 413 are both 50% in an ideal state.

[0069] Optionally, a distance between the polarization beam splitter 411 and the beam splitter 413 is set according to a curvature of the polarization beam splitter 411 to satisfy the Gaussian imaging rule. The distance between the wave plate 412 and the polarization beam splitter 411 is 0 or the distance between the wave plate 412 and the beam splitter 413 is 0.

[0070] In an example, Figure 4A The incident light ray O1 in the system 41 is an outgoing light ray of an object to be imaged, and the incident light ray O1 is, for example, a vertically polarized light. The polarization beam splitter 411 transmits the vertically polarized light and reflects the horizontally polarized light. Based on this, the polarization beam splitter 411 transmits the outgoing light ray O1 to the wave plate 412. The wave plate 412 performs phase modulation (i.e., phase delay of π / 2) on the light ray O1 to obtain a circularly polarized light O2. When the circularly polarized light O2 passes through the beam splitter 413, 50% of the light energy is transmitted and 50% of the light energy (i.e., the light energy of the light ray O2-1) is reflected to the wave plate 412. The wave plate 412 performs phase modulation on the circularly polarized light O2-1 to obtain a linearly polarized light O3, which has a phase delay of π relative to the light ray O1, i.e., the polarization direction of the light ray O3 is rotated by 90° or -90° relative to the polarization direction of the light ray O1, and the light ray O3 is in a horizontal direction. Since the polarization beam splitter 411 reflects the horizontally polarized light, the light ray O3 is reflected by the polarization beam splitter 411 to the wave plate 412 after being incident on the polarization beam splitter 411. The light ray O3 is phase-modulated by the wave plate 412 to obtain a circularly polarized light O4. The light transmitted by the beam splitter 413 is used for imaging.

[0071] In another embodiment, the incident light O1 can be a horizontally polarized light. In this embodiment, the polarization beam splitter 411 transmits the horizontally polarized light and reflects the vertically polarized light.

[0072] It can be understood that the above Figure 4A The above description is an example of an implementation of the optical imaging system of the present application and does not limit the optical imaging system of the present application. In another embodiment, at least one of the polarization beam splitter and the beam splitter in the optical imaging system can also be another optical element, for example, if the polarization beam splitter isFigure 4A The shape of the polarization beam splitter 411 in the optical imaging system can also be any other curved mirror, such as Figure 4B shown.

[0073] Figure 4B An optical imaging system 42 (hereinafter referred to as system 42) is illustrated. System 42 includes: a polarization beam splitter 421, a wave plate 422, and a beam splitter 423 arranged in sequence along the transmission direction of the incident light. The function and form of the polarization beam splitter 421 in system 42 can refer to the polarization beam splitter 411 in system 41, and the function and form of the wave plate 422 can refer to the wave plate 412 in system 41. Beam splitter 423 is a beam splitter with a convex surface facing the wave plate 422. The transmittance of beam splitter 423 is, for example, 70%, and the reflectance is, for example, 30%. The functions and optical paths of the various optical components can be referred to the description of system 41 and will not be repeated here.

[0074] It should be noted that, according to the principle of real image formation, light reflected from polarizing beam splitter 421 and transmitted through beam splitter 423 should converge. In system 42, light reflected from beam splitter 423 diverges, while light reflected from polarizing beam splitter 421 converges. Therefore, to ensure light convergence, the curvature of polarizing beam splitter 421 should be greater than that of beam splitter 423. The relationship between the curvatures of polarizing beam splitter 421 and beam splitter 423 can be determined based on the actual imaging position requirements, etc.

[0075] In addition, optionally, when the polarization beam splitter is in the form of system 41 and the scenario shown in system 41 , the beam splitter can also be implemented as an optical element with a concave surface facing the wave plate.

[0076] Optionally, the polarization beam splitter in the optical imaging system may also be implemented as an optical element of other shapes.

[0077] like Figure 4C As shown, Figure 4C An optical imaging system 43 (hereinafter referred to as system 43) is illustrated. System 43 includes a polarization beam splitter 431, a wave plate 432, and a beam splitter 433 arranged in sequence along the propagation direction of the incident light. In system 43, the convex surface of polarization beam splitter 431 faces wave plate 432, while the concave surface of beam splitter 433 faces wave plate 432. The transmittance of beam splitter 433 is, for example, 70%, and the reflectance is, for example, 30%. The functions of the various optical components and the optical path can be found in the description of system 41 and will not be repeated here.

[0078] In system 43, light transmitted through polarization beam splitter 431 diverges. Light reflected from beam splitter 433 and then reflected through polarization beam splitter 431 converges again after passing through beam splitter 433. Therefore, to ensure that beam splitter 433 converges the light reflected from polarization beam splitter 431 into a real image when transmitting it out, the curvature of beam splitter 433 in system 43 should be greater than the curvature of polarization beam splitter 431. The amount of this greater curvature can be flexibly set based on actual needs and is not a limitation here.

[0079] Optionally, the polarization beam splitter 431 in the system 43 may be replaced by a planar optical element, which will not be described in detail here.

[0080] It is understandable that the above Figures 4A to 4C These are all exemplary implementations of the optical imaging system to form a real image. If the optical imaging system forms a virtual image, Figure 4B The curvature of the polarization beam splitter 421 should be smaller than the curvature of the beam splitter 423. Figure 4C The curvature of the middle beam splitter 433 should be smaller than the curvature of the polarization beam splitter 431 , which will not be described in detail here.

[0081] In summary, the optical imaging system provided by the embodiment of the present application includes a first spectroscopic element, a first optical phase modulation element, and a second spectroscopic element arranged in sequence according to the transmission direction of the light emitted by the object to be imaged, wherein the first optical phase modulation element is a quarter wave plate. For the light incident on the first optical phase modulation element, the second spectroscopic element reflects part of the incident light and transmits another part of the incident light. The first spectroscopic element transmits the light emitted by the object to be imaged, and reflects the light from the second spectroscopic element and passing through the first optical phase modulation element. In this way, if the light emitted by the object to be imaged is polarized light in the first polarization direction, then the first spectroscopic element transmits the polarized light in the first polarization direction. Furthermore, the light emitted by the first spectroscopic element is phase-modulated for the first time by the first optical phase modulation element and then enters the second spectroscopic element, and the light reflected by the second spectroscopic element passes through the first optical phase modulation element again and enters the first spectroscopic element. At this time, the polarized light in the first polarization direction passes through the first optical phase modulation element twice, resulting in a phase delay of π, that is, the polarization direction of the light is rotated 90°, that is, the light incident on the first beam splitter element is polarized light in the second polarization direction, and the first beam splitter element reflects the polarized light in the second polarization direction. The light reflected by the first beam splitter element passes through the first optical phase modulation element and the second beam splitter element, thereby enabling the transmitted light to be imaged. It can be seen that the optical imaging system provided in the embodiment of the present application utilizes the polarization of light to still achieve reflection and transmission of light and ultimately imaging between the sequentially arranged optical elements, without the need to tilt any optical element, so that the space occupied by each optical element is smaller, thereby reducing the volume of the imaging device.

[0082] Referring to Figure 5 Corresponding to the above, Figure 5 An imaging device 50 is shown, which comprises a display element 51 and an optical imaging system 52 as shown in any one of the systems 30 to 43, the display element 51 being configured to emit light of an object to be imaged.

[0083] According to the above description of the embodiments, the incident light of the optical imaging system 52 is linearly polarized light of a first polarization direction, based on which the display element 51 can be implemented as any one of the following: a physical object to be imaged illuminated by linearly polarized light, a physical object to be imaged emitting linearly polarized light, a display showing an image of the object to be imaged, etc.

[0084] For example, if the light emitted by the display is linearly polarized light, the light emitted by the display can be used as the incident light of the optical imaging system 52. If the light emitted by the display is not linearly polarized light, a linearly polarized light processing device can be arranged in the direction of the light emitted by the display, and then the light emitted by the linearly polarized light processing device can be used as the incident light of the optical imaging system 52.

[0085] In some embodiments, if the imaging device 50 is used to form a real image, the distance from the light emitting surface of the display element 51 to the imaging plane of the real image is greater than or equal to the distance from the light emitting surface to the second light splitting element, which can ensure that the real image is imaged outside the imaging device 50.

[0086] According to the foregoing description of the optical imaging system, since the optical elements in the optical imaging system are arranged in sequence, any optical element does not need to be placed obliquely, so that the space occupied by each optical element is smaller, thereby being able to reduce the volume of the imaging device.

[0087] Each part of the specification is described in a progressive manner, and the same or similar parts between each embodiment can be referred to each other, and each embodiment mainly introduces the difference from other embodiments, and the related part can be referred to the description of the method embodiment.

[0088] Although the preferred embodiments of the present application have been described, those skilled in the art can make further changes and modifications to the embodiments once they know the basic inventive concept. Therefore, the appended claims are intended to be interpreted as including all the preferred embodiments and all the changes and modifications falling within the scope of the present application.

[0089] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application also intends to include these modifications and variations.

Claims

1. An optical imaging system, characterized in that: The system comprises: A first beam splitter element, a first optical phase modulation element, and a second beam splitter element are sequentially arranged according to the transmission direction of the light emitted by the object to be imaged; The incident light of the first beam splitter is polarized light in a first polarization direction, the first beam splitter transmits the polarized light in the first polarization direction and reflects the polarized light in a second polarization direction, the first polarization direction being orthogonal to the second polarization direction; The second beam splitter element reflects a portion of the light emitted by the first optical phase modulation element and transmits another portion of the light emitted by the first optical phase modulation element; When the second beam splitter element is an element with a convex surface facing the first optical phase modulation element, the curvature of the first beam splitter element is greater than the curvature of the second beam splitter element; When the first beam splitter element is a planar element, or a convex surface of the first beam splitter element faces the first optical phase modulation element, the second beam splitter element is a concave surface of the second beam splitter element faces the first optical phase modulation element, and the curvature of the second beam splitter element is greater than the curvature of the first beam splitter element; The optical imaging system is characterized in that the reflectivity of the second beam splitter element to light satisfies: 10% to 90%, or the transmittance of the second beam splitter element to light satisfies: 10% to 90%; The optical imaging system is characterized in that the optical imaging system further comprises: a second optical phase modulation element and a polarizer arranged in sequence according to the transmission output direction of the second beam splitting element, The polarizer has an absorption axis and a transmission axis, and the angle between the transmission axis of the polarizer and the optical axis of the second optical phase modulation element is 45°, -45°, 135° or -135°; When the angle between the optical axis of the second optical phase modulation element and the optical axis of the first optical phase modulation element is 0° or 180°, the polarizer transmits polarized light in the first polarization direction; When the angle between the optical axis of the second optical phase modulation element and the optical axis of the first optical phase modulation element is 90° or −90°, the polarizer transmits polarized light in the second polarization direction.

2. The optical imaging system according to claim 1, wherein: At least one of the first beam splitter element and the second beam splitter element has a converging effect on light, so that the second beam splitter element has a converging effect on the light reflected by the first beam splitter element after being emitted, or the emitted light of the second beam splitter element diverges.

3. The optical imaging system according to claim 1, wherein: The first beam splitter element includes a planar element and a curved element. When the first beam splitter element is the curved element, the concave surface of the first beam splitter element faces the first optical phase modulation element, or the convex surface of the first beam splitter element faces the first optical phase modulation element.

4. The optical imaging system according to claim 2, wherein: If at least one of the first beam splitter element and the second beam splitter element has a converging effect on light, When the concave surface of the first beam splitter element faces the first optical phase modulation element, the second beam splitter element is a planar element, an element with a convex surface facing the first optical phase modulation element, or an element with a concave surface facing the first optical phase modulation element.

5. An imaging device, characterized in that: The optical imaging system comprises a display element and an optical imaging system, wherein the display element is used to emit light of an object to be imaged, the light is polarized light in a first polarization direction, and the optical imaging system is as described in any one of claims 1 to 4.

6. The imaging device according to claim 5, wherein The display element is implemented as any of the following: The entity of the object to be imaged is illuminated by linearly polarized light, the entity of the object to be imaged emits linearly polarized light, a display showing an image of the object to be imaged, the display emits linearly polarized light, or the display and a linearly polarized light processing device emit linearly polarized light.

7. The imaging device according to claim 5 or 6, characterized in that When the imaging device forms a real image, the distance from the light-emitting surface of the display element to the real image imaging plane is greater than or equal to the distance from the light-emitting surface to the second light-splitting element.

Images