Deflective reflection assembly, retinal projection display apparatus and retinal projection display method

Abstract

A deflective reflection assembly (10), a retinal projection display apparatus and a retinal projection display method. The deflective reflection assembly (10) comprises a plurality of deflective reflection units (100). Each deflective reflection unit (100) comprises: a selective reflection layer (11) corresponding to a point-of-sight position and used for transmitting first circularly polarized light and reflecting second circularly polarized light having an opposite rotation direction so as for imaging at the point-of-sight position; and a polarization converting layer (12) stacked in front of the selective reflection layer (11) and used for, when in an on state, converting the polarization rotation direction of the first circularly polarized light so as to form the second circularly polarized light to be reflected by the selective reflection layer (11) and, when in an off state, keeping the polarization rotation direction of the first circularly polarized light so as to transmit same through the selective reflection layer (11).

Description

Deflection reflection component, retinal projection display device and retinal projection display method

[0001] Related applications

[0002] This application claims priority to Chinese patent application number 202310945300.6, filed on July 28, 2023, entitled “Deflection and reflection component, retinal projection display device and method thereof,” the entire text of which is hereby incorporated by reference. Technical Field

[0003] The present application relates to the field of near-eye display technology, and in particular to a deflection and reflection component, a retinal projection display device and a method thereof. Background Art

[0004] Retinal projection display technology has a very small exit pupil, making it difficult to meet the eyebox requirements of near-eye displays. Therefore, pupil dilation is required to increase the size of the eyebox. Currently, two common pupil dilation methods include viewpoint tracking and viewpoint replication. Viewpoint tracking uses an eye-tracking camera to capture and provide feedback on the position of the human eye in real time, and then changes the viewpoint position by changing the angle of the incident light, thereby maintaining the viewpoint position consistent with the human eye position. Viewpoint replication utilizes the multiplexing recording characteristics of volume holography (HOE) to simultaneously generate multiple viewpoints. This ensures that a viewpoint always enters the human eye as the eyeball changes position, thereby achieving pupil dilation.

[0005] However, the related viewpoint tracking method relies on mechanical structures such as rotating mirrors or galvanometers to change the angle of the incident light, which not only increases the size of the device but also easily introduces additional aberrations. The related viewpoint replication method easily generates crosstalk or dark areas between adjacent viewpoints due to the simultaneous existence of multiple viewpoints. At the same time, the multiplexing recording of HOE will also lead to a reduction in the light efficiency of each viewpoint.

[0006] In order to solve the above problems, the relevant patent US11175507B2 discloses a technical solution that uses a polarization holographic grating to achieve changes in viewpoint position and combines eye movement to achieve pupil expansion in retinal projection display. Although it superimposes a multilayer liquid crystal polarization grating on a semi-reflective and semi-transparent device or a reflective HOE, and controls the deflection direction of the light beam by applying a voltage to each layer of the liquid crystal polarization grating, so that the incident light is reflected by the semi-reflective and semi-transparent device or the reflective HOE, and the multilayer liquid crystal polarization grating is combined with eye movement to adjust the viewpoint position in real time, thereby achieving pupil expansion; however, the semi-reflective and semi-transparent device or reflective HOE and the multilayer liquid crystal polarization grating used in this solution are two different optical devices, and the overall structure is relatively complex. In addition, the multilayer liquid crystal polarization grating needs to work simultaneously to achieve changes in viewpoint position, which makes control more difficult.

[0007] Summary of the Invention

[0008] According to various embodiments of the present application, the present application provides a deflection reflection component, a retinal projection display device and a method thereof.

[0009] In a first aspect, the present application provides a deflection reflection assembly, comprising a plurality of deflection reflection units stacked front to back, each of the deflection reflection units comprising:

[0010] a selective reflection layer corresponding to a viewpoint position, configured to transmit a first circularly polarized light and reflect a second circularly polarized light having a rotation direction opposite to that of the first circularly polarized light to form an image at the viewpoint position; and

[0011] a polarization conversion layer stacked before the selective reflective layer, wherein the polarization conversion layer is controlled to switch between an on state and a off state; when the polarization conversion layer is in the on state, the polarization conversion layer is used to convert the polarization rotation of the first circularly polarized light to form the second circularly polarized light and be reflected by the corresponding selective reflective layer; when the polarization conversion layer is in the off state, the polarization conversion layer is used to maintain the polarization rotation of the first circularly polarized light so as to transmit the corresponding selective reflective layer.

[0012] In one embodiment, the selective reflection layer is a cholesteric liquid crystal device.

[0013] In one embodiment, the polarization conversion layer is an electrically controlled half-wave plate.

[0014] In one embodiment, the first circularly polarized light is one of left-handed circularly polarized light and right-handed circularly polarized light; and the second circularly polarized light is the other of the left-handed circularly polarized light and the right-handed circularly polarized light.

[0015] In a second aspect, the present application further provides a retinal projection display device, comprising:

[0016] an image source having a light emitting path for emitting image light along the light emitting path;

[0017] Any of the above-mentioned deflecting and reflecting components, wherein the deflecting and reflecting component is arranged in the light emitting path of the image source; and

[0018] An eye tracker is correspondingly arranged on the side of the deflecting and reflecting component, and is used to capture the pupil position to obtain the current viewpoint position, so as to reflect the image light from the image source through the deflecting and reflecting component to form an image at the current viewpoint position.

[0019] In one embodiment, when the polarization conversion layer in the deflecting and reflecting assembly that is located before the selective reflection layer corresponding to the current viewpoint position is controlled to be in an on state, the other polarization conversion layers in the deflecting and reflecting assembly are all in an off state.

[0020] In one embodiment, when the polarization conversion layer in the deflecting reflection component that is located before the selective reflection layer corresponding to the current viewpoint position is controlled to be in an open state, all polarization conversion layers in the deflecting reflection component that are located before the polarization conversion layer in the open state are in a closed state.

[0021] In one embodiment, the image source is a laser scanning mirror or a light source with a spatial light modulator.

[0022] In one embodiment, the eye tracker is an eye camera.

[0023] In one embodiment, the eye tracker is located on a side of the deflecting and reflecting component away from the image source.

[0024] In a third aspect, the present application further provides a retinal projection display method, comprising the steps of:

[0025] The image light is emitted to the deflection and reflection component through the image source;

[0026] Capturing pupil position through an eye tracker to obtain the current viewpoint position; and

[0027] The polarization conversion layer in the deflecting and reflecting component, which is located before the selective reflection layer corresponding to the current viewpoint, is controlled to switch its state so as to reflect the image light from the image source through the deflecting and reflecting component to form an image at the current viewpoint.

[0028] In one embodiment, the step of controlling the polarization conversion layer in the deflecting and reflecting assembly, which is located before the selective reflection layer corresponding to the current viewpoint position, to switch its state so as to reflect the image light from the image source through the deflecting and reflecting assembly to form an image at the current viewpoint position comprises the following steps:

[0029] Based on the current viewpoint position, applying a voltage to an electrically controlled half-wave plate located before the cholesteric liquid crystal device corresponding to the current viewpoint position in the deflecting and reflecting assembly to switch the electrically controlled half-wave plate from a closed state to an open state, so that the backward-propagating first circularly polarized light is converted into the backward-propagating second circularly polarized light after passing through the electrically controlled half-wave plate;

[0030] Reflecting the second circularly polarized light propagating backward through the cholesteric liquid crystal device corresponding to the current viewpoint position so as to propagate forward to the electrically controlled half-wave plate; and

[0031] The electrically controlled half-wave plate converts the second circularly polarized light propagating forward into the first circularly polarized light propagating forward after passing through the electrically controlled half-wave plate.

[0032] In one embodiment, the step of controlling the polarization conversion layer in the deflecting and reflecting assembly, which is located before the selective reflection layer corresponding to the current viewpoint position, to switch its state so as to reflect the image light from the image source through the deflecting and reflecting assembly to form an image at the current viewpoint position, further includes the steps of:

[0033] After the forward-propagating second circularly polarized light is converted into the first circularly polarized positive light through the electrically controlled half-wave plate, the voltage applied to the electrically controlled half-wave plate is removed to switch the electrically controlled half-wave plate from an open state to a closed state, so that the first circularly polarized light maintains its polarization direction unchanged after passing through the electrically controlled half-wave plate.

[0034] The details of one or more embodiments of the present application are set forth in the following drawings and description to make other features, objects, and advantages of the present application more readily apparent. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the conventional technology, the following briefly introduces the drawings required for use in the embodiments or the conventional technology descriptions. Obviously, the drawings described below are merely embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the disclosed drawings without any creative work.

[0036] FIG1 is a schematic structural diagram of a retinal projection display device according to an embodiment of the present application.

[0037] FIG. 2 is an enlarged schematic diagram of a portion A of the deflecting and reflecting assembly in the retinal projection display device of FIG. 1 .

[0038] FIG3 shows a schematic diagram showing the principle of a deflecting and reflecting unit in an open state in the deflecting and reflecting assembly according to the above embodiment of the present application.

[0039] FIG4 is a schematic diagram showing the principle of a deflecting and reflecting unit in a deflecting and reflecting assembly in the above embodiment of the present application in a closed state.

[0040] FIG5 is a flow chart of a retinal projection display method according to an embodiment of the present application.

[0041] FIG6 shows an example of a state control step in the retinal projection display method according to the above embodiment of the present application.

[0042] Explanation of the main component symbols: 10. Deflection and reflection assembly; 100. Deflection and reflection unit; 11. Selective reflection layer; 110. Cholesteric liquid crystal device; 12. Polarization conversion layer; 120. Electrically controlled half-wave plate; 20. Image source; 30. Eye tracker.

[0043] The above description of the main component symbols is combined with the accompanying drawings and specific implementation methods to further illustrate this application in detail. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0045] Those skilled in the art should understand that, in the disclosure of this application, the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like to indicate orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing this application 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 this application.

[0046] In this application, the term "a" or "an" in the claims and the specification should be understood as "one or more." That is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the element may be multiple. Unless the disclosure of this application clearly indicates that the number of the element is only one, the term "a" or "an" should not be understood as unique or singular, and the term "a" or "an" should not be understood as a limitation on quantity.

[0047] In the description of this application, 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 this application, 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 this application can be understood according to the specific circumstances.

[0048] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" 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 present application. 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 can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0049] Considering that the transflective device or reflective HOE and multi-layer liquid crystal polarization grating used in related technical solutions are two different optical devices, the overall structure is relatively complex, and the multi-layer liquid crystal polarization grating needs to work simultaneously to achieve the change of viewpoint position, which is relatively difficult to control. Therefore, this application creatively proposes a deflection and reflection assembly, a retinal projection display device and a method thereof, which can achieve effective pupil expansion while simplifying the overall structure, reducing the overall volume and weight, which is conducive to meeting the miniaturization and lightweight requirements of near-eye display devices.

[0050] Specifically, referring to Figures 1 to 4 of the accompanying drawings in the specification of the present application, according to one embodiment of the present application, a retinal projection display device is provided, which may include a deflecting and reflecting component 10, an image source 20 and an eye tracker 30; the deflecting and reflecting component 10 is arranged in the light emitting path of the image source 20; the eye tracker 30 is correspondingly arranged on the side of the deflecting and reflecting component 10, for capturing the pupil position to obtain the current viewpoint position, so as to reflect the image light from the image source 20 through the deflecting and reflecting component 10 to form an image at the current viewpoint position.

[0051] More specifically, as shown in Figures 2 to 4, the deflecting and reflecting assembly 10 may include a plurality of deflecting and reflecting units 100 stacked front to back; each of the deflecting and reflecting units 100 includes a selective reflection layer 11 corresponding to a viewpoint position and a polarization conversion layer 12 stacked in front of the selective reflection layer 11. The selective reflection layer 11 is used to transmit a first circularly polarized light and reflect a second circularly polarized light having a rotation direction opposite to the first circularly polarized light to form an image at the corresponding viewpoint position. The polarization conversion layer 12 is controlled to switch between an open state and a closed state; when the polarization conversion layer 12 is in the open state, the polarization conversion layer 12 is used to convert the polarization rotation direction of the first circularly polarized light to form a second circularly polarized light to be reflected by the corresponding selective reflection layer 11; when the polarization conversion layer 12 is in the closed state, the polarization conversion layer 12 is used to maintain the polarization rotation direction of the first circularly polarized light so that it can pass through the corresponding selective reflection layer 11. It can be understood that the front-to-back stacking mentioned in the present application refers to stacking along the light-emitting path of the image source 20, that is, the light-emitting path of the image source 20 extends from front to back; in other words, the polarization conversion layer 12 in each of the deflection and reflection units 100 is located on the side of the corresponding selective reflection layer 11 close to the image source 20, so that the image light emitted by the image source 20 first passes through the polarization conversion layer 12 and then passes through the corresponding selective reflection layer 11.

[0052] The image source 20 of the present application is used to emit image light having a first circular polarization state along the light-emitting path, that is, the image light emitted by the first image source 20 will pass through the polarization conversion layer 12 in the closed state and the corresponding selective reflection layer 11, and will only be reflected by the selective reflection layer 11 corresponding to the polarization conversion layer 12 in the open state and imaged at the corresponding viewpoint position; on the other hand, since the distances between the selective reflection layers 11 in the multiple deflection and reflection units 100 stacked in front and behind and the image source 20 are different, the image light emitted by the image source 20 can be imaged at different viewpoint positions after being reflected by different selective reflection layers 11.

[0053] In this way, the retinal projection display device of the present application only needs to control the polarization conversion layer 12 located before the selective reflection layer 11 corresponding to the current viewpoint position to switch to the open state according to the current viewpoint position tracked in real time by the eye tracker 30, and control the other polarization conversion layers 12 to switch to the closed state, so that the image light from the image source 20 is reflected to form an image at the current viewpoint position, that is, the real-time change of the viewpoint position can be achieved, thereby expanding the eye box range; in other words, the reflection function and the viewpoint deflection function in the retinal projection display device of the present application are integrated into the same device of the deflection reflection component 10, the structure is relatively simple, and only one polarization conversion layer 12 needs to be controlled to work (in the open state) at the same time, and the control of the entire device is simpler.

[0054] In addition, compared with the related viewpoint tracking pupil expansion scheme, the retinal projection display device of the present application does not require a mechanical adjustment structure, that is, the image light emitted by the image source of the present application does not need to use mechanical structures such as rotating mirrors or galvanometers to change the incident angle, so that the device can be smaller and more conducive to achieving lightweight optical and mechanical design requirements, and there will be no aberration problems caused by the deflection of the incident light; compared with the related viewpoint replication pupil expansion scheme, the retinal projection display device of the present application is achieved by reflecting the image light of the same incident angle at different times through the selective reflection layer 11 at different positions in the deflection reflection component 10, so that only one viewpoint light always enters the human eye to achieve pupil expansion, and there is no problem of reduced light efficiency due to the multiplexing recording of volume holograms, and there is no crosstalk problem.

[0055] Optionally, as shown in Figures 3 and 4, the selective reflection layer 11 of the present application can be implemented as a cholesteric liquid crystal device 110. It can be understood that cholesteric liquid crystal (CLC) is a material with strong polarization selectivity. It reflects all circularly polarized light of a specific rotation direction at an angle that satisfies the Bragg law, and can transmit / pass all circularly polarized light of another rotation direction. In addition, the optical properties of cholesteric liquid crystal are determined by the orientation layer. Based on the specific orientation layer design and exposure, it can have an optical focal length similar to that of a lens, and is a planar optical element.

[0056] Optionally, as shown in Figures 3 and 4, the polarization conversion layer 12 of the present application can be implemented as an electrically controlled half-wave plate 120 so as to control the polarization rotation of the transmitted light by applying a voltage; that is, the electrically controlled half-wave plate 120 is switched by applying a voltage thereto, that is, when a voltage is applied to the electrically controlled half-wave plate 120, the electrically controlled half-wave plate 120 is in an open state to change the polarization rotation of the transmitted light; when no voltage is applied to the electrically controlled half-wave plate 120, the electrically controlled half-wave plate 120 is in a closed state to maintain the polarization rotation of the transmitted light, which greatly reduces the difficulty of state switching and makes the retinal projection display device of the present application easy to control.

[0057] For example, right-handed circularly polarized light (RCP for short) is used as the first circularly polarized light, and left-handed circularly polarized light (LCP for short) is used as the second circularly polarized light: all cholesteric liquid crystal devices 110 are configured to reflect LCP and transmit RCP; the image light emitted by the image source 20 is RCP. Thus, as shown in FIG3 , when the electrically controlled half-wave plate 120 in a deflecting and reflecting unit 100 is applied with a voltage to be in an open state, the RCP from the image source 20 will be converted into LCP after passing through the electrically controlled half-wave plate 120 to be incident on the corresponding cholesteric liquid crystal device 110 and reflected, and then after being reflected by the cholesteric liquid crystal device 110, it will still be LCP to be converted into RCP again after passing through the electrically controlled half-wave plate 120; at this time, as shown in FIG4 , the electrically controlled half-wave plates 120 in the other deflecting and reflecting units 100 are not applied with a voltage to be in a closed state, so that the RCP will not change the polarization direction after passing through these electrically controlled half-wave plates 120, and will still be RCP, and can directly pass through the corresponding cholesteric liquid crystal device 110. In this way, the retinal projection display device of the present application can achieve that there is always a viewpoint light entering the human eye, and the viewpoint position at different times can change with the pupil position, thereby increasing the eye box of the retinal projection display.

[0058] It is understandable that in other examples of the present application, the first circularly polarized light may be left-handed circularly polarized light; correspondingly, the second circularly polarized light may be right-handed circularly polarized light. This is accomplished by configuring a corresponding cholesteric liquid crystal device 110 , which is not described in detail in the present application.

[0059] According to the above embodiments of the present application, the image source 20 of the present application can be implemented as, but not limited to, a laser scanning mirror (LBS), can also be implemented as a light source with a spatial light modulator, or can also be implemented as other micro-projection optical machines, as long as it can project the first circularly polarized light to the deflection and reflection component 10, and this application will not elaborate on this.

[0060] Optionally, the eye tracker 30 of the present application can be implemented as an eye camera, but is not limited to being implemented as an eye camera, for capturing and feeding back the pupil position in real time to obtain the current viewpoint position in real time; and then controlling the corresponding polarization conversion layer 12 in the deflection and reflection component 10 in real time to be in an open state, so as to facilitate the real-time change of the viewpoint position and better achieve the effect of eye box expansion.

[0061] Optionally, as shown in FIG. 1 , the eye tracker 30 may be located on a side of the deflecting and reflecting component 10 away from the image source 20 to prevent structural and light interference between the eye tracker 30 and the image source 20 .

[0062] The retinal projection display device of the present application may further include a control system (not shown in the figure), which is communicatively connected to the deflection and reflection component 10 and the eye tracker 30. The control system is used to control the polarization conversion layer 12 corresponding to the current viewpoint position in the deflection and reflection component 10 to be in an open state based on the current viewpoint position obtained by the eye tracker 30, so as to reflect the image light through the corresponding selective reflection layer 11 to form an image at the current viewpoint position, thereby automatically achieving a pupil expansion effect. It is understood that the control system of the present application can be implemented as, but is not limited to, a control panel mounted on a head-mounted device such as a glasses frame or a helmet, so that the retinal projection display device can be worn for near-eye display.

[0063] Optionally, the control system is communicatively connected to the image source 20, and is used to control the image source 20 to emit the first circularly polarized light to the deflecting and reflecting assembly 10. In addition, the control system is further used to control the eye tracker 30 to capture the current position of the pupil as the current viewpoint position.

[0064] Although the cholesteric liquid crystal device 110 of the present application has strong polarization selectivity, natural light is not affected when passing through the cholesteric liquid crystal device 110. Therefore, natural light from the external environment can enter the human eye through the deflecting and reflecting component 10. That is, while the user views the virtual image formed by reflection through the deflecting and reflecting component 10, he can also view the external environment through the deflecting and reflecting component 10, allowing the user to obtain an augmented reality experience.

[0065] As shown in FIG5 , an embodiment of the present application further provides a retinal projection display method, which may include the following steps:

[0066] S100: emitting image light to a deflection and reflection component through an image source;

[0067] S200: Capturing the pupil position through an eye tracker to obtain the current viewpoint position; and

[0068] S300: Controlling the polarization conversion layer in the deflecting and reflecting component, which is located before the selective reflection layer corresponding to the current viewpoint position, to switch its state, so as to reflect the image light from the image source through the deflecting and reflecting component to form an image at the current viewpoint position.

[0069] It is worth noting that steps S100 and S200 of the present application can be performed simultaneously or sequentially. Although step S200 of the present application is performed before step S300, the time interval between steps S200 and S300 is extremely short, so that the image light can be projected into the pupil in a timely manner for retinal projection display. It is understandable that the time between steps S200 and S300 of the present application can be implemented as the response time of the electrically controlled half-wave plate, which is generally within 10ms.

[0070] Optionally, in step S200 of the present application: the pupil position is captured in real time by an eye tracker to obtain the current viewpoint position in real time; thus, in step S300 of the present application: the corresponding polarization conversion layer can be controlled to be in an open state in real time to ensure that the image light from the image source can be imaged at the current viewpoint position in real time, so as to achieve real-time changes in the viewpoint position to match the real-time changes in the pupil position, thereby better expanding the eye box.

[0071] Optionally, in step S300 of the present application: when the polarization conversion layer located before the selective reflection layer corresponding to the current viewpoint position in the deflecting reflection component is controlled to be in an open state, the other polarization conversion layers in the deflecting reflection component can all be in a closed state, ensuring that the image light from the image source is only reflected by the selective reflection layer corresponding to the current viewpoint position and accurately imaged at the current viewpoint position. It is understandable that in other examples of the present application, when the polarization conversion layer located before the selective reflection layer corresponding to the current viewpoint position in the deflecting reflection component is controlled to be in an open state, the polarization conversion layer located after the selective reflection layer corresponding to the current viewpoint position can also be in an open state. It only needs to control all polarization conversion layers located before the polarization conversion layer in the open state to be in a closed state, which can still ensure that the image light from the image source is only reflected by the selective reflection layer corresponding to the current viewpoint position and accurately imaged at the current viewpoint position, thereby achieving the effect of expanding the eye box.

[0072] Optionally, in an example of the present application, as shown in FIG6 , step S300 of the retinal projection display method may include the following steps:

[0073] S310: Based on the current viewpoint position, applying a voltage to an electrically controlled half-wave plate located before the cholesteric liquid crystal device corresponding to the current viewpoint position in the deflecting and reflecting assembly to switch from a closed state to an open state, so that the backward-propagating first circularly polarized light is converted into the backward-propagating second circularly polarized light after passing through the electrically controlled half-wave plate;

[0074] S320: reflecting the second circularly polarized light propagating backward through the cholesteric liquid crystal device 110 corresponding to the current viewpoint position so as to propagate forward to the electrically controlled half-wave plate; and

[0075] S330: The electrically controlled half-wave plate is used to convert the second circularly polarized light propagating forward into the first circularly polarized light propagating forward after passing through the electrically controlled half-wave plate.

[0076] Optionally, in an example of the present application, as shown in FIG6 , step S300 of the retinal projection display method may further include the following steps:

[0077] S340: After the second circularly polarized light propagating forward is converted into the first circularly polarized light through the electrically controlled half-wave plate, the voltage applied to the electrically controlled half-wave plate is removed to switch from an open state to a closed state, so that the first circularly polarized light maintains its polarization direction unchanged after passing through the electrically controlled half-wave plate.

[0078] The technical features of the above embodiments can 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.

[0079] The above embodiments merely illustrate several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A deflection reflection component, characterized in that: The invention comprises a plurality of deflection reflection units stacked front and back, each of the deflection reflection units comprising: A selective reflection layer corresponding to a viewpoint position, configured to transmit a first circularly polarized light and reflect a second circularly polarized light having a rotation direction opposite to that of the first circularly polarized light to form an image at the viewpoint position; and A polarization conversion layer is stacked before the selective reflection layer, and the polarization conversion layer is controlled to switch between an open state and a closed state; when the polarization conversion layer is in the open state, the polarization conversion layer is used to convert the polarization rotation of the first circularly polarized light to form the second circularly polarized light and be reflected by the corresponding selective reflection layer; when the polarization conversion layer is in the closed state, the polarization conversion layer is used to maintain the polarization rotation of the first circularly polarized light to pass through the corresponding selective reflection layer.

2. The deflection reflection assembly according to claim 1, wherein: The selective reflection layer is a cholesteric liquid crystal device.

3. The deflection reflection assembly according to claim 1, wherein: The polarization conversion layer is an electrically controlled half-wave plate.

4. The deflection reflection assembly according to any one of claims 1 to 3, wherein: The first circularly polarized light is one of left-handed circularly polarized light and right-handed circularly polarized light; and the second circularly polarized light is the other of the left-handed circularly polarized light and the right-handed circularly polarized light.

5. A retinal projection display device, characterized in that: include: an image source having a light emitting path for emitting image light along the light emitting path; The deflecting and reflecting component according to any one of claims 1 to 4, wherein the deflecting and reflecting component is arranged in the light emitting path of the image source; as well as An eye tracker is correspondingly arranged on the side of the deflection and reflection component, and is used to capture the pupil position to obtain the current viewpoint position, so as to reflect the image light from the image source through the deflection and reflection component to form an image at the current viewpoint position.

6. The retinal projection display device according to claim 5, wherein: When the polarization conversion layer in the deflecting reflection component that is located before the selective reflection layer corresponding to the current viewpoint position is controlled to be in an open state, the other polarization conversion layers in the deflecting reflection component are all in a closed state.

7. The retinal projection display device according to claim 5, wherein: When the polarization conversion layer located before the selective reflection layer corresponding to the current viewpoint position in the deflecting reflection component is controlled to be in the open state, all polarization conversion layers located before the polarization conversion layer in the open state in the deflecting reflection component are in the closed state.

8. The retinal projection display device according to claim 5, wherein: The image source is a laser scanning mirror or a light source with a spatial light modulator.

9. The retinal projection display device according to claim 5, wherein: The eye tracker is an eye camera.

10. The retinal projection display device according to claim 5, wherein: The eye tracker is located on a side of the deflecting and reflecting component away from the image source.

11. A retinal projection display method, characterized in that: Includes steps: The image light is emitted to the deflection reflection component through the image source; The pupil position is captured by an eye tracker to obtain the current viewpoint position; as well as The polarization conversion layer in the deflection and reflection component and located before the selective reflection layer corresponding to the current viewpoint position is controlled to switch its state, so that the image light from the image source is reflected by the deflection and reflection component to form an image at the current viewpoint position.

12. The retinal projection display method according to claim 11, wherein: The step of controlling the polarization conversion layer in the deflection reflection component and located before the selective reflection layer corresponding to the current viewpoint position to switch the state so as to reflect the image light from the image source through the deflection reflection component to form an image at the current viewpoint position comprises the steps of: Based on the current viewpoint position, applying a voltage to the electrically controlled half-wave plate located before the cholesteric liquid crystal device corresponding to the current viewpoint position in the deflection and reflection assembly, so that the electrically controlled half-wave plate is switched from a closed state to an open state, so that the first circularly polarized light propagating backward is converted into the second circularly polarized light propagating backward after passing through the electrically controlled half-wave plate; Reflecting the second circularly polarized light propagating backward through the cholesteric liquid crystal device corresponding to the current viewpoint position to propagate forward to the electrically controlled half-wave plate; as well as By means of the electrically controlled half-wave plate, the second circularly polarized light propagating forward is converted into the first circularly polarized light propagating forward after passing through the electrically controlled half-wave plate.

13. The retinal projection display method according to claim 12, wherein: The step of controlling the polarization conversion layer in the deflection reflection component and located before the selective reflection layer corresponding to the current viewpoint position to switch the state so as to reflect the image light from the image source through the deflection reflection component to form an image at the current viewpoint position further comprises the steps of: After the second circularly polarized light propagating forward is converted into the first circularly polarized light through the electrically controlled half-wave plate, the voltage applied to the electrically controlled half-wave plate is removed to switch the electrically controlled half-wave plate from an open state to a closed state, so that the first circularly polarized light maintains its polarization direction unchanged after passing through the electrically controlled half-wave plate.

Images