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DE-102024132990-A1 - Head-mounted display, holder for a lens for a head-mounted display and method for assembling a head-mounted display

DE102024132990A1DE 102024132990 A1DE102024132990 A1DE 102024132990A1DE-102024132990-A1

Abstract

A head-mounted display (HMD) (10) with a vision correction lens (16) is proposed, which is lightweight and inexpensive to manufacture. The HMD (10) has a frame (12) that includes a mounting space (20) for receiving a waveguide (14) and a holder (18) with a lens (16) inserted into the holder (18). The holder (18) is configured for detachable attachment to the frame (12). The holder (18) has a support element (40) that projects beyond a lens surface (28) of the lens (16) when the lens (16) is inserted into the holder (18). The support part (40) of the holder rests against an adjacent waveguide surface (30) of the waveguide (14) when the holder (18) with the lens (16) is inserted into the installation space (20) to provide an air gap (26) between the waveguide surface (30) and the adjacent lens surface (28). A holder (18) for a lens (16) and a method for assembling an HMD (10) are also proposed.

Inventors

  • Georg Michels

Assignees

  • tooz technologies GmbH

Dates

Publication Date
20260513
Application Date
20241112

Claims (19)

  1. Head-mounted display (HMD), comprising a frame (12) having a mounting space (20) for receiving a waveguide (14) and a holder (18) with a lens (16) inserted into the holder (18), wherein the holder (18) is configured for detachable attachment to the frame (12), wherein the holder (18) has a support part (40) that extends beyond a lens surface (28) of the lens (16) when the lens (16) is inserted into the holder (18), and bears against an adjacent waveguide surface (30) of the waveguide (14) when the holder (18) with the lens (16) is inserted into the mounting space (20) to provide an air gap (26) between the waveguide surface and the adjacent lens surface (28, 30).
  2. HMD after Claim 1 , wherein at least one of the frame (12) and the holder (18) comprises a fixing structure for snapping the holder (18) with the lens (16) into the installation space (20).
  3. HMD after Claim 2 , wherein the fixing structure has one or more projections (46) in an inner wall of the frame (12) which limits the installation space (20), wherein the one or more projections (46) are designed to allow the holder (18) with the lens (16) to snap into the installation space (20) and to hold the holder (18) within the installation space (20).
  4. HMD after one of the Claims 2 or 3 , wherein the fixing structure has one or more frame grooves (60) in an inner wall of the frame (12), and the holder (18) has one or more frame engagement parts (62) for engaging in the one or more frame grooves (60), wherein the one or more frame grooves (60) and the one or more frame engagement parts (62) are designed to allow the holder (18) with the lens (16) to snap into the installation space (20) and to hold the holder (18) within the installation space (20).
  5. HMD after one of the Claims 1 until 4 , wherein the holder (18) is configured to grip the lens (16) at a periphery of the lens (16) by surface friction and/or form fit.
  6. HMD after one of the Claims 1 until 5 , wherein the lens (16) has a lens groove (50) and the holder (18) has a lens engagement part (52) for engaging in the lens groove (50) when the lens (16) is inserted into the holder (18).
  7. HMD after one of the Claims 1 until 6 , wherein the holder (18) is designed as a ring or tube made of an elastic material and has an inner circumference in a relaxed, unstretched state which is smaller than an outer circumference of the lens (16).
  8. HMD after one of the Claims 1 until 7 , wherein the support part (40) of the holder (18) is configured to seal the air gap (26) and/or to protect a circumferential edge of the lens (16).
  9. HMD after one of the Claims 1 until 8 , wherein the holder (18) has a tab (54) for pulling the holder (18) with the lens (16) out of the installation space (20) of the frame (12).
  10. HMD after one of the Claims 1 until 9 , wherein the waveguide (14) comprises a waveguide package comprising a waveguide substrate and a protective cover encapsulating the waveguide for protection thereof, or wherein the waveguide (14) comprises a stacked arrangement of a waveguide (22) and one or more protective layers (24) on one or both sides of the waveguide (22).
  11. HMD after one of the Claims 1 until 10 , which further comprises another optical element (74) which is included in the installation space (20) of the frame (12).
  12. HMD after Claim 11 , wherein a further air gap (76) is provided between the waveguide (14) and the further optical element (74).
  13. HMD after Claim 11 or 12 , wherein the holder (18) is configured to hold the additional optical element (74), or the smart glasses have an additional holder for holding the additional optical element (74), wherein the additional holder is configured for detachable attachment to the frame.
  14. HMD after one of the Claims 1 until 13 , wherein the holder (18) is configured to detachably accommodate the lens (16) and the waveguide (14).
  15. HMD after one of the Claims 1 until 14 , wherein the frame (12) has a first frame component (12a) and at least a second frame component (12b) which can be attached to the first frame component (12a), wherein the first and the at least one second frame component (12a, 12b) jointly support the waveguide (14) and the lens (16) when the first and the at least one second frame component (12a, 12b) are attached to each other.
  16. Holder for a lens (16) configured for detachable attachment to a frame (12) of a head-mounted display (10) with a waveguide (14), wherein the holder (18) has a support part (40) that extends beyond a lens surface (28) of the lens (16) when the lens (16) is inserted into the holder (18), and bears against an adjacent waveguide surface (30) of the waveguide (14) when the holder (18) with the lens (16) is attached to the frame (12) to provide an air gap (26) between the waveguide surface and the adjacent lens surface (28, 30).
  17. A method for assembling a head-mounted display (10), comprising: providing a frame (12) with a mounting space (20) for receiving a waveguide (14); arranging the waveguide (14) in the mounting space; inserting a lens (16) into a holder (18) such that a support part (40) of the holder (18) projects beyond a lens surface (28) of the lens (16); and attaching the holder (18) with the lens (16) to the frame (12) such that the support part (40) abuts a waveguide surface (30) of the waveguide (14) adjacent to the lens surface (28) to provide an air gap (26) between the waveguide surface and the adjacent lens surface (28, 30).
  18. Procedure according to Claim 17 , wherein the insertion of the lens (16) into the holder (18) involves extending the holder (18) over a periphery of the lens (16).
  19. Procedure according to Claim 17 or 18 , wherein attaching the holder (18) with the lens (16) to the frame (12) includes snapping the holder (18) into the installation space (20) of the frame.

Description

The present invention relates to head-mounted displays, such as smart glasses or virtual reality headsets. The present invention further relates to a holder for a lens for a head-mounted display. In addition, the present invention relates to a method for assembling a head-mounted display. Head-mounted display (HMD) systems enable a user to visually immerse themselves in an extended reality (XR) environment, such as a virtual reality (VR), augmented reality (AR), or mixed reality (MR) environment, by projecting virtual image content onto the user's eye. Smart glasses are AR or MR devices worn on the eye or head, which may include displays that add virtual image content alongside or to what a wearer sees through the smart glasses; that is, they overlay virtual image content, provided by an image generator, onto the wearer's field of vision. Virtual reality headsets are devices worn on the eye or head that do not allow the wearer to directly see a real environment through opaque displays, but only present the wearer with virtual image content provided by the image generator, although in this case information about the real environment can be captured, e.g. with cameras or LiDARs, and added to the virtual image content. A head-mounted display (HMD) or near-eye display (NED) typically comprises an image generator or projector system and an optical system to transmit the image light generated by the projector system as a virtual image to the user's eye. For example, HMD optical systems are known that are based on a transparent or opaque planar or curved waveguide designed to guide the image light coupled at an input structure by total internal reflection to an output structure, where the image light is coupled out to the user's eye or eyes. To provide an HMD with a correction for the user's visual impairments, such as prescription smart glasses, it is known to create an optical structure in which a waveguide is augmented with one or more prescription (Rx) lenses positioned over the user's field of vision. In other words, such an optical structure can comprise a stacked arrangement of a waveguide and an Rx lens or Rx lenses. In a see-through HMD, such a stacked optical arrangement can have two Rx lenses positioned on either side of a waveguide (to act on both the virtual images and the real-world environment), while an opaque HMD can have a single Rx lens positioned on one eye side of a waveguide. One of the technical challenges in the design of such optical systems is to provide an air gap or vacuum gap around the waveguide, i.e., between the waveguide surfaces and the surfaces of the Rx lens(es) in the stacked arrangement. This is necessary to create a sufficiently large refractive index step across the waveguide surfaces and thereby ensure total internal reflection of the image light guided within the waveguide. Ideally, the HMD optical system should incorporate a removable Rx lens(es) to allow for customization to a user's specific prescription. In the present disclosure, the term “air gap” includes not only a gap filled with natural air, but also a gap filled with a fluid or a gap that is free of any material, i.e., a vacuum gap. Various designs of HMDs with a waveguide and Rx lenses are known, including an HMD with a head-mounted support structure that accommodates a planar waveguide, a non-removable lens, and a removable lens that is coupled to the head-mounted support structure by means of magnets, as for example in US 11,815,685 B2 and US 10,983,352 B2 as described, or use bayonet fittings, i.e., push-and-turn mechanisms, as described in US 2024/007773 A1 described, as well as a smart glasses design in which a support frame accommodates a planar waveguide and an Rx lens, which is coupled to the frame using an elastic ring that fits into a groove at the edge of the lens and a corresponding recess in the frame, as described in CN 220419686 U is described. In CN 220419686 U An air gap between the planar waveguide and the Rx lens is provided by a mechanical design of the support frame, which has a part that protrudes between them to act as a spacer. Although the in CN 220419686 U While the revealed solution, based on a mechanical design, is simple and inexpensive to manufacture, it does not allow the Rx lens to be removable. This design poses a high risk of mechanical damage to the waveguide if a user attempts to disassemble the smart glasses. Disassemble and reassemble the HMD to replace the Rx lens without professional assistance. The technical designs revealed in the other documents mentioned above involve an HMD with a removable Rx lens, but with a more complex design that results in increased manufacturing costs. Therefore, there is a need for a simple mechanical arrangement for attaching an Rx lens or lenses to a waveguide in an HMD, which allows the Rx lens or lenses to be removable, i.e., which enables self-assembly and self-disassembly of the system by a user in certain cases, for example, when a sim