Optical lens assemblies and near-eye display devices for near-eye displays

Abstract

An optical lens assembly for a near-eye display device includes a lightbox and a diffractive optical element (DOE). The lightbox has a first layer facing the display screen of the near-eye display device and a second layer facing the DOE. The lightbox is configured to receive first light from the display screen of the near-eye display device and transmit at least a portion of the first light through a bent optical path to the DOE, and the first and second layers are flat. The DOE is aligned with the optical axis of the eye and is configured to receive second light from the lightbox and focus the second light towards the eye.

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims priority to U.S. Patent Application No. 18 / 336,014, filed on June 15, 2023, the entire content of which is incorporated herein by reference.

[0002] This application relates to the field of near - eye display technology, and more particularly, to an optical lens assembly for a near - eye display and a near - eye display device.

Background Art

[0003] In recent years, near - eye displays (NEDs) have been rapidly popularized. There is a need to develop compact, high - performance, and low - cost NED devices. In addition, it is also necessary to control artifacts such as pupil jitter and distortion behavior in NED devices.

Summary of the Invention

Problems to be Solved by the Invention

[0004] The disclosed methods and systems are aimed at solving one or more of the above - mentioned problems and other problems.

Means for Solving the Problems

[0005] One aspect of the present disclosure provides an optical lens assembly for a near - eye display device. The optical lens assembly includes a light box and a diffractive optical element (DOE). The light box has a first layer facing the display screen of the near - eye display device and a second layer facing the DOE. The light box is configured to receive first light from the display screen of the near - eye display device and transmit at least a part of the first light to the DOE through a bent optical path, and the first layer and the second layer are flat. The DOE is aligned with the optical axis of the eye and is configured to receive second light from the light box and converge the second light onto the eye.

[0006] Another aspect of the present disclosure provides a near-eye display device comprising a display screen configured to emit first light to an optical lens assembly, and the optical lens assembly comprising a lightbox and a diffractive optical element (DOE). The lightbox has a first layer facing the display screen and a second layer facing the DOE. The lightbox is configured to receive first light from the display screen of the near-eye display device and to transmit at least a portion of the first light to the DOE through a bent optical path, and the first and second layers are flat. The DOE is aligned with the optical axis of the eye and is configured to receive second light from the lightbox and to focus the second light towards the eye.

[0007] Other aspects of this disclosure may be understood by those skilled in the art in light of the description, claims, and drawings of this disclosure. [Brief explanation of the drawing]

[0008] [Figure 1] This figure shows an exemplary near-eye display (NED) device consistent with a particular embodiment of the present disclosure. [Figure 2] This figure shows a comparison between an NED device with a widened optical path in related technologies and an exemplary NED device with a bent optical path consistent with a particular embodiment of the present disclosure. [Figure 3] This figure shows a computer system consistent with embodiments of the present disclosure. [Modes for carrying out the invention]

[0009] The technical solutions in embodiments of the present invention will be described below with reference to the accompanying drawings. Wherever possible, the same reference numerals will be used throughout the drawings to refer to the same or similar parts. Obviously, the embodiments described are only a part of, not all, embodiments of the present invention. Other embodiments that can be obtained by those skilled in the art based on embodiments of the present invention without creative effort will fall within the scope of this disclosure.

[0010] This disclosure provides an optical lens assembly for near-eye display (NED) devices. The NED device may be a virtual reality (VR) device such as a VR headset, an augmented reality device such as AR glasses, and / or any other suitable display device. The optical lens assembly for the NED device may include a lightbox that provides an optical path bending function and a diffractive optical element (DOE) that provides an imaging focusing function. Optical path bending allows for a more compact structure for the NED device. In some embodiments, the functions of the lightbox and DOE do not overlap (for example, the optical path function is provided only by the lightbox and not by the DOE), thereby increasing the flexibility of structural design and improving manufacturing and assembly yields.

[0011] Figure 1 shows an exemplary near-eye display (NED) device consistent with a particular embodiment of the present disclosure. As shown in Figure 1, the NED device may include an optical lens assembly 100 and a display screen 200. The display screen 200 may be a light-emitting system configured to emit light onto the optical lens assembly 100. The emitted light corresponds to image pixels output by a processor coupled to the NED device for the user to view.

[0012] The optical lens assembly 100 includes a lightbox 102 and a DOE 104. The lightbox 102 is configured to receive a first light from the display screen 200 and transmit at least a portion of the first light through a bent optical path to the DOE 104. The DOE 104 is configured to receive a second light from the lightbox 102 and focus the second light towards the eye.

[0013] The lightbox 102 includes a first layer 1022 facing the display screen and a second layer 1024 facing the DOE 104. The optical path bending function of the lightbox 102 can be realized by the reflective surfaces of the two layers. The reflective surfaces may include one or more of the following: a reflective polarizer, a beam splitter, etc. Other optical elements such as waveplates / phase difference plates, lenses, filters, and diffracting elements may also be used in the two layers of the lightbox 102. In some embodiments, the first layer 1022 and the second layer 1024 are parallel and both have flat surfaces. That is, the lightbox 102 itself does not contribute to the convergence / focusing of light from the display screen 200 to the eye 300, but only needs to bend the optical path to provide a compact form factor for the NED device.

[0014] In some embodiments, a medium can be filled into the lightbox 102 between the first layer 1022 and the second layer 1024. The medium may be a solid (e.g., glass or plastic), a liquid, and / or a gas (e.g., air or other types of gas). In one embodiment, the volume of medium filled into the lightbox 102 can be adjusted based on the user's visual acuity. For example, the volume of medium filled into the lightbox 102 can be increased to provide a shortened light path if the user is farsighted, and decreased to provide an extended light path if the user is nearsighted. In another embodiment, the distance d1 between the first layer 1022 and the second layer 1024 can be adjusted based on the user's visual acuity. For example, by moving the first layer 1022 and / or the second layer 1024 closer or further away, the distance d1 can be decreased to provide a shortened light path if the user is farsighted, or increased to provide an extended light path if the user is nearsighted. In some embodiments, distance adjustment can be achieved manually via a mechanical mechanism coupled to the lightbox, or automatically using electromechanical components coupled to the lightbox, in response to a control signal generated by the NED device. In some embodiments, different lightbox models can be manufactured to suit different visual acuities, and the user can select a lightbox model that matches their visual acuity to be installed in the NED device.

[0015] In some embodiments, the first layer 1022 may include a beam splitter facing the display screen 200 and a first phase difference plate facing the second layer 1024, and the second layer 1024 may include a reflective polarizer configured to reflect light having a first polarization characteristic and transmit light having a second polarization characteristic.

[0016] The optical axes of the DOE 104 and the eye 300 can be aligned. The optical axis of the DOE 104 can be perpendicular to the first layer 1022 and the second layer 1024. In some embodiments, unlike prior art pancake lens designs, the optical path of light from the display screen 200 to the eye 300 in the exemplary embodiments disclosed herein does not bend in the space between the DOE 104 and the lightbox 102. In some embodiments, the DOE 104 itself does not bend the optical path. In some embodiments, the DOE 104 does not provide reflective and / or polarizing functions to the incident light, thereby providing greater flexibility in determining the material, type, curvature, and / or shape of the DOE. In some embodiments, the surface of the DOE 104 is not flat. For example, the surface 1042 of the DOE 104 facing the lightbox 102 may not be flat but curved and / or have a surface like a Fresnel lens. The other surface of the DOE 104 facing the eye may also be curved. In some embodiments, the DOE 104 may include at least one of an injection-molded DOE, a holographic film, or a Fresnel lens surface. The DOE 104 (e.g., having a curved surface and without a polarizer) can also contribute to chromatic aberration correction. As a result, when the optical lens assembly 100 is applied to an AR device with a see-through camera, it can provide better synchronization with the see-through camera without additional image adjustment or processes, distortion control is easily achieved (based on a flat surface lightbox and DOE), and lateral color is well corrected.

[0017] In exemplary embodiments of the disclosed optical lens assembly 100, each individual component (i.e., lightbox 102 and DOE 104) may have a designated function that does not overlap. In other words, only one component of the optical lens assembly 100 (e.g., lightbox 102) provides the optical path bending function, and only one component of the optical lens assembly 100 (e.g., DOE 104) provides the imaging / focusing function. In this way, compared to conventional pancake lens designs in which at least two lenses are involved in both optical path bending and optical focusing, the alignment of at least two lenses is important in the conventional art, while the alignment between the DOE 104 and lightbox 102 is more flexible because the two components do not share a focusing function, thus improving manufacturing and assembly yield. Furthermore, the flat surface of the lightbox 12 facilitates stacking without compromising its optical performance, and the disclosed optical lens assembly 100 is less susceptible to quality degradation factors such as lens tilt and / or light source tilt. This also results in a more user-friendly experience, as the NED device has greater resistance to accidental drops and other external forces. Furthermore, additional optical components can be easily added to the optical lens assembly 100 without technical difficulties (e.g., without having to consider the optical power of the lightbox). Moreover, while the focusing system of conventional technology is fixed, the disclosed optical lens assembly 100 can provide focus adjustment based on the user's visual acuity.

[0018] Figure 2 shows a comparison between an NED device with a widened optical path in related technology and an exemplary NED device with a bent optical path consistent with a particular embodiment of the present disclosure. As shown in Figure 2, the optical path p1 of the lens assembly between the display screen and the eye in the prior art (shown at the top of Figure 2) passes directly through the curved DOE and is not bent, whereas the optical path p2 of the optical lens assembly 100 between the display screen and the eye (shown at the bottom of Figure 2) based on an exemplary embodiment of the present disclosure is bent. In this way, the physical distance requirement between the display screen and the eye is shortened, a compact form factor is provided to the NED device, and the physical size of the NED device is reduced.

[0019] The lower part of Figure 2 further illustrates an exemplary structure of the disclosed optical lens assembly 100. As shown in Figure 2, the first layer 1022 of the lightbox 102 includes a 50 / 50 beam splitter and a quarter-wavelength phase difference plate, and the second layer 1024 includes at least a first reflective polarizer facing the first layer 1022.

[0020] In some embodiments, the light from the display screen may have circular polarization in a first rotational direction (e.g., left-hand circular polarization). A 50 / 50 beam splitter is configured to receive the first light, reflect 50% of the first light back, and transmit 50% of the first light to a quarter-wavelength phase plate in the first layer 1022. The quarter-wavelength phase plate is configured to change 50% of the first light into a third light having first linear polarization. The third light passes through the medium filled in the lightbox 102 to a first reflecting polarizer in the second layer 1024. The first reflecting polarizer is configured to reflect the third light back to the quarter-wavelength phase plate. The quarter-wavelength phase plate is further configured to change the third light having first linear polarization into a fourth light having circular polarization in a first direction. When the fourth light reaches the 50 / 50 beam splitter, the 50 / 50 beam splitter is further configured to reflect 50% of the fourth light back to a quarter-wavelength phaser, changing its circular polarization to a second rotation direction (e.g., right-hand circular polarization). The quarter-wavelength phaser is further configured to change the reflected light into a fifth light having a second linear polarization, which is orthogonal to the first linear polarization. The first reflecting polarizer is configured to allow the fifth light to pass through.

[0021] In one embodiment, the second layer 1024 of the lightbox 102 may include only one reflective polarizer. In another embodiment, the second layer 1024 of the lightbox may include multiple reflective polarizers. Additional reflective polarizers can enhance contrast and reduce noise in the optical system (e.g., stray light, ghost imaging).

[0022] In the example shown below FIG. 2, the second layer 1024 includes a first reflective polarizer, a second reflective polarizer, and a half-wave retardation plate disposed between the first reflective polarizer and the second reflective polarizer. The polarization selectivity of the first reflective polarizer is orthogonal to the polarization selectivity of the second reflective polarizer. When the fifth light passes through the first reflective polarizer and reaches the half-wave retardation plate, its polarization characteristic changes to the first linearly polarized light. The second reflective polarizer transmits the light of the first linearly polarized light. In another embodiment, the second layer 1024 may not include a half-wave retardation plate, and the polarization selectivity of the first reflective polarizer may not be orthogonal to the polarization selectivity of the second reflective polarizer.

[0023] FIG. 3 shows a computer system capable of implementing the disclosed near-eye display system / device according to some embodiments of the present disclosure. As shown in FIG. 3, the system 3000 includes at least one processor 302 and a storage medium 304. The system 3000 also includes a display 306 configured to display content to a user wearing a near-eye display device, a communication module 308, and one or more buses for coupling the devices to each other. The display 306 may include the display screen 200 and the optical lens assembly 100 shown in FIG. 1. Certain devices may be omitted, or other devices may be included.

[0024] System 3000 can be a head-mounted display (HMD) such as virtual reality (VR) glasses, augmented reality (AR) glasses, and extended reality (XR) glasses. The content displayed on display 306 can include text, images, and / or videos. Display screen 200 can emit light corresponding to the image pixels of the displayed content. The image pixels of the displayed content may be pre-distorted by system 3000 (e.g., processor 302 and / or display 306) to correspond to a near-eye display scenario such as according to eye movements. In some embodiments, the image pixels can be adjusted to synchronize with the see-through camera of the AR device. In some embodiments, spectral operations can be performed to increase or decrease the brightness of individual colors on display screen 200, which can help users with color vision deficiencies perceive full color.

[0025] Processor 302 can include one or more of any suitable processor. In certain embodiments, processor 302 can include multiple cores for multi-threaded or parallel processing and / or a graphics processing unit (GPU). Processor 302 can execute a sequence of computer program instructions to perform various processes such as a display control program. Storage medium 304 may be a non-transitory computer-readable storage medium, and may include memory modules such as ROM, RAM, flash memory modules, erasable and rewritable memory, as well as mass storage such as CD-ROM, USB drives, hard disks. Storage medium 304 may store a computer program for performing various processes when executed by processor 302. Storage medium 304 may also include one or more databases for storing specific data such as text scripts, library data, display configuration data, and can perform specific operations such as database searches and data retrievals on the stored data.

[0026] The communication module 308 may include a network device for establishing a connection over a network. The peripheral device 312 may include additional I / O devices such as a controller, keyboard, and speaker.

[0027] During operation, the processor 302 may be configured to perform various operations, such as executing instructions stored in the storage medium 304, processing image content, and sending the image content to the display 306 for display.

[0028] The sequence numbers of the embodiments described herein are for illustrative purposes only and do not indicate priority of the embodiments.

[0029] If the integration unit in the embodiments described above is implemented in the form of a software function unit and sold or used as an independent product, the integration unit may be stored in the computer-readable storage medium described above. Based on this understanding, the technical solutions of the present disclosure, or any part of them that contribute to related technologies, or all or part of the technical solutions, may be implemented in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for instructing one or more computer devices (which may be personal computers, servers, network devices, etc.) to perform all or part of the steps of the methods in the embodiments of the present disclosure.

[0030] The descriptions of the embodiments described herein have different emphasis. For aspects not described in detail in one embodiment, refer to the relevant descriptions in other embodiments.

[0031] In some embodiments provided in this disclosure, it should be understood that the disclosed clients may be implemented in other ways. The embodiments of the apparatus described above are merely illustrative. For example, the division of units is merely a division of logical functions, and other division methods may be used in actual implementation. For example, multiple units or components may be combined, or integrated into another system, or some features may be omitted or not performed. In addition, the coupling, direct coupling, or communication connection between the displayed or described components may be an indirect coupling or communication connection via some interface, unit, or module, and may be in an electrical or other form.

[0032] Units described as separate parts may or may not be physically separate. Parts shown as units may or may not be physical units, may be located in one place, or may be distributed across multiple network units. Some or all of the units may be selected according to the actual requirements to achieve the objectives of the solution in the embodiment.

[0033] In addition, the functional units in the embodiments of this disclosure can be integrated into a single processing unit, or each unit can exist physically independently, or two or more units can be integrated into a single unit. The aforementioned integrated unit can be implemented in hardware form or in the form of a software functional unit.

[0034] The principles and implementations of this disclosure are described using specific embodiments herein, but the foregoing description of embodiments is intended only to aid in understanding the methods and core concepts of the methods of this disclosure. On the other hand, those skilled in the art can modify specific embodiments and scopes in accordance with the spirit of this disclosure. In conclusion, nothing in this specification should be construed as a limitation on this disclosure. [Explanation of symbols]

[0035] 100 Optical lens assemblies 102 Lightbox 104 DOE 200 display screen 300 eyes 302 Processors 304 Storage medium 306 displays 308 Communication Module 312 Peripherals 1022 First layer 1024 Second layer 1042 surface 3000 System

Claims

1. An optical lens assembly for a near-eye display device, A lightbox having a first layer facing the display screen of the near-eye display device and a second layer facing a diffractive optical element (DOE), wherein the lightbox is configured to receive first light from the display screen of the near-eye display device and transmit at least a portion of the first light to the DOE via a bent optical path, and the first layer and the second layer are flat. The DOE is configured to be aligned with the optical axis of the eye, receive a second light from the lightbox, and focus the second light towards the eye. An optical lens assembly comprising:

2. The optical lens assembly according to claim 1, wherein the surface of the DOE facing the lightbox is curved.

3. The first layer of the lightbox comprises a beam splitter facing the display screen and a first phase difference plate facing the second layer. The second layer of the lightbox comprises at least one reflective polarizer configured to reflect light having a first polarization characteristic and transmit light having a second polarization characteristic. The optical lens assembly according to claim 1.

4. The optical lens assembly according to claim 3, wherein the beam splitter is a 50 / 50 beam splitter.

5. The optical lens assembly according to claim 3, wherein the first phase difference plate is a quarter-wavelength phase difference plate.

6. The beam splitter is configured to receive the first light having circular polarization in a first direction, The first phase difference plate is configured to change a portion of the first light transmitted through the beam splitter into a third light having a first linear polarization, The second layer is configured to reflect the third light having the first linear polarization and return it to the first phase difference plate. The first phase difference plate is further configured to change the third light having the first linear polarization to the fourth light having the first circular polarization, The beam splitter is further configured to reflect a portion of the fourth light to the first phase difference plate, and the reflected light has circular polarization in the second direction. The first phase difference plate is further configured to change the reflected light into a fifth light having a second linear polarization, wherein the first linear polarization is perpendicular to the second linear polarization. The second layer is further configured to transmit at least a portion of the fifth light to the DOE as the second light having the second linear polarization. The optical lens assembly according to claim 5.

7. The optical lens assembly according to claim 1, wherein the second layer of the lightbox includes a plurality of reflective polarizers.

8. The second layer of the lightbox includes a first reflective polarizer, a second reflective polarizer, and a half-wavelength phase difference plate disposed between the first reflective polarizer and the second reflective polarizer. The polarization selectivity of the first reflecting polarizer is orthogonal to the polarization selectivity of the second reflecting polarizer. The optical lens assembly according to claim 7.

9. The optical lens assembly according to claim 1, wherein the DOE comprises at least one of an injection-molded DOE, a holographic film, or a Fresnel lens surface.

10. The optical lens assembly according to claim 1, wherein the DOE does not bend the optical path of the second light.

11. A display screen configured to emit a first light into an optical lens assembly. A near-eye display device comprising, The optical lens assembly is A lightbox having a first layer facing the display screen of the near-eye display device and a second layer facing a diffractive optical element (DOE), wherein the lightbox is configured to receive first light from the display screen of the near-eye display device and transmit at least a portion of the first light to the DOE via a bent optical path, and the first layer and the second layer are flat. The DOE is configured to be aligned with the optical axis of the eye, receive a second light from the lightbox, and focus the second light towards the eye. Equipped with, Near-eye display device.

12. The near-eye display device according to claim 11, wherein the surface of the DOE facing the lightbox is curved.

13. The first layer of the lightbox comprises a beam splitter facing the display screen and a first phase difference plate facing the second layer. The second layer of the lightbox comprises at least one reflective polarizer configured to reflect light having a first polarization characteristic and transmit light having a second polarization characteristic. The near-eye display device according to claim 11.

14. The near-eye display device according to claim 13, wherein the beam splitter is a 50 / 50 beam splitter.

15. The near-eye display device according to claim 13, wherein the first phase difference plate is a quarter-wavelength phase difference plate.

16. The display screen is configured to emit the first light having circular polarization in a first direction, The first phase difference plate is configured to change a portion of the first light transmitted through the beam splitter into a third light having a first linear polarization, The second layer is configured to reflect the third light having the first linear polarization and return it to the first phase difference plate. The first phase difference plate is further configured to change the third light having the first linear polarization to the fourth light having the first circular polarization, The beam splitter is further configured to reflect a portion of the fourth light to the first phase difference plate, and the reflected light has circular polarization in the second direction. The first phase difference plate is further configured to change the reflected light into a fifth light having a second linear polarization, wherein the first linear polarization is perpendicular to the second linear polarization. The second layer is further configured to transmit at least a portion of the fifth light to the DOE as the second light having the second linear polarization. The near-eye display device according to claim 15.

17. The near-eye display device according to claim 11, wherein the second layer of the lightbox includes a plurality of reflective polarizers.

18. The second layer of the lightbox includes a first reflective polarizer, a second reflective polarizer, and a half-wavelength phase difference plate disposed between the first reflective polarizer and the second reflective polarizer. The polarization selectivity of the first reflecting polarizer is orthogonal to the polarization selectivity of the second reflecting polarizer. The near-eye display device according to claim 17.

19. The near-eye display device according to claim 11, wherein the DOE comprises at least one of an injection-molded DOE, a holographic film, or a Fresnel lens surface.

20. The near-eye display device according to claim 11, wherein the DOE does not bend the optical path of the second light.

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