Display system for eyewear

Abstract

A display system for a head-mounted device (HMD) including a lens, the display system comprising: a display area located on the lens of the HMD, the lens having a base angle and a pantoscopic angle; a display engine and optics; and a prism for redirecting an output of the optics to the display area on the lens of the HMD taking into account the base angle and the pantoscopic angle.

Description

[0001] Related applications

[0002] This application claims priority to U.S. Provisional Application No. 63 / 203,174, filed July 12, 2021, and incorporates the entire contents of that application. Technical Field

[0003] This invention relates to displays, and more particularly to decoupling the position of light engines and optics from the position of images. Background Technology

[0004] In head-mounted displays (HMDs), the construction of the display, lighting, and projection optics, as well as the location where the image is to be projected, is extremely complex.

[0005] Figure 1A A typical display 110, optics 120, and image output 130 are shown. Generally, the lighting and projection optics are in a line, and the output of the optics is displayed to the user.

[0006] Figure 1B and Figure 1C A typical display 140 with illumination and projection optics 150 is shown, the output of which is input to waveguide 160. This causes image output 170 to be displaced from the positions of display 140 and optics 150. Figure 1C It can be seen that when the output of the optical device 150 is coupled to the waveguide 160 at a certain angle, the light coupled through the output of the waveguide 160 is also emitted at a certain angle. Attached Figure Description

[0007] The invention is illustrated by way of example and not limitation in the accompanying drawings, and the same reference numerals in the drawings refer to similar elements, and in the drawings:

[0008] Figure 1A This is a diagram of one implementation of a standard display engine in the prior art.

[0009] Figure 1B This is an illustration of an implementation of a standard display engine with waveguides in the prior art.

[0010] Figure 1C This is an illustration of an implementation of a standard display engine with a waveguide in the prior art when light is incident at a certain angle.

[0011] Figure 2 This is an illustration of one embodiment of a display engine with a prism that provides an output at an angle relative to the position of the optics.

[0012] Figure 3AThis is a diagram illustrating one implementation of a system including an achromatic prism.

[0013] Figure 3B This is an illustration of another implementation of a system with an achromatic prism.

[0014] Figures 4A to 4C This is an implementation scheme for an achromatic prism.

[0015] Figure 5A This is an illustration of one embodiment of a system with an achromatic prism having optical magnification.

[0016] Figure 5B This is a diagram illustrating one implementation of a system with a refractive and diffractive prism.

[0017] Figure 5C This is a diagram illustrating one implementation of a system with a refractive / diffractive prism.

[0018] Figure 6 This is a diagram illustrating one implementation of a system with a prism and a waveguide.

[0019] Figure 7A This is a diagram illustrating one implementation of a system with two exit pupils that uses an achromatic prism.

[0020] Figure 7B This is a diagram illustrating one implementation of a system with laser illumination and two exit pupils.

[0021] Figure 8A and Figure 8B This is a diagram illustrating one implementation of a system with dichroic exit pupils.

[0022] Figure 9A This is a diagram illustrating one implementation of a waveguide-based system with two exit pupils.

[0023] Figure 9B This is a diagram illustrating one implementation of a system with two exit pupils utilizing two waveguides.

[0024] Figure 10 This is a flowchart of an implementation scheme for a prism design system.

[0025] Figure 11A and Figure 11B This is an illustration of one embodiment of the eyeglasses system of the present invention. Detailed Implementation

[0026] The system of the present invention provides a design for a head-mounted display that enables the display and optical elements to be displaced from the position of the displayed image. A prism is used to shift the angle of the outgoing beam, thereby shifting the position of the output image. In one embodiment, the prism is designed to shift the image such that the output axis is not aligned with the axis of the rest of the system. In one embodiment, an achromatic prism is used.

[0027] This design takes into account the display to lenses with a forward tilt angle and a base angle, thus enabling a display within the form factor of a head-mounted device (HMD). In one embodiment, this allows the display system to be mounted within an eyeglass form factor while providing good optical performance. In one embodiment, an achromatic prism is used to avoid chromatic aberration. In another embodiment, a prism with refractive and diffractive surfaces is used. In one embodiment, magnification can be applied to the achromatic prism. In one embodiment, light redirected from the prism can be directed to the user's eye via a waveguide. In one embodiment, the system may include multiple exit pupils for different colors, each exit pupil having a separate prism.

[0028] The following detailed description of embodiments of the invention is taken with reference to the accompanying drawings, in which like reference numerals indicate similar elements, thereby illustrating specific embodiments for practicing the invention by way of example. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. Those skilled in the art will understand that other embodiments can be utilized, and logical, mechanical, electrical, functional, and other changes can be made without departing from the scope of the invention. Therefore, the following detailed description should not be construed as limiting, and the scope of the invention is defined only by the appended claims.

[0029] Figure 11A and Figure 11BOne embodiment of eyeglasses is shown, which can be designed to provide an augmented reality (AR) and / or virtual reality (VR) and / or mixed reality (MR) display. In one embodiment, an image is displayed on a waveguide 1150 embedded in the eyeglass lens. As shown, the waveguide 1150 is not at a perpendicular angle to the optics 1130, but rather at a compound angle to it. In this illustration, the optics are embedded in the arm 1110 of the eyeglasses 1100. In other embodiments, the optics may be positioned in the central region, above the eyes, or at other locations. However, in any configuration, there is typically a compound angle between the output of the optics 1130 and the input coupler of the waveguide or other elements used for display. The displacement between the output of the optics 1130 and a reference plane can be indicated by the optical axis angle (which has a top component and a side component). Additionally, the lens is typically angled between the top (base angle) and the side (forward tilt angle). Tilting is possible along all three axes. The combination of different angles constitutes the total displacement between the input coupler of the waveguide (or other display element) and the optical axis of the illumination optics 1130, known as the compound angle. Therefore, the design of this invention uses a prism to adjust the compound angle and decouples the positions of the display engine and optics from the final image display position. This design is highly flexible enough to adapt to any head-mounted device, including eyeglasses, goggles, or any other display configuration. Of course, these techniques are also applicable to form factors independent of eyeglasses, where the display and illumination / projection optics are positioned at an angle to the output image.

[0030] Figure 2 This is an illustration of one embodiment of a display engine with a prism that provides an output angled relative to the position of the optics. This angled output is designed to adjust the composite angle between the optical axis of the illumination and projection optics 220 and a preferred angle of the image output 240, as described above. In one embodiment, the display 210 may include a light-emitting diode (LED) display, a micro-LED display, a scanning laser display, a liquid crystal on silicon (LCoS), a digital micromirror device (DMD), or other types of display. The output of the display 210 is transmitted via one or more illumination and projection optics 220. Use of such optics 220 is known in the art. Optics 220 may include illumination optics, projection optics, or a combination of illumination and projection optics. Although optics 220 are shown as a single frame, those skilled in the art will understand that such optics may include multiple lenses and mirrors. In one embodiment, the elements included in the illumination and projection optics may include one or more lenses, mirrors, holographic optics, and other optical elements.

[0031] The output of optics 220 is transmitted to prism 230. Prism 230 alters the exit angle of the light, thereby positioning the output image 240 at the correct angle for display. However, using a single prism 230 can lead to problems such as chromatic aberration. This system can address these chromatic aberrations using various adjustments to prism 230. Exemplary adjustments to prism 230 are described below.

[0032] Figure 3A This is an illustration of one embodiment of a system including achromatic prisms. The achromatic prism 330 is capable of altering the angle of light from illumination and projection optics 320 without causing chromatic aberration. In one embodiment, the achromatic prism 330 is a plurality of prisms bonded together from different types of glass with different refractive indices. In one embodiment, the type of glass or other material used determines the number of wedges. In one embodiment, the shape, size, and material of the achromatic prism are selected based on the bandwidth of the light (i.e., a specific wavelength range), the pupil size, and the deflection angle.

[0033] In one embodiment, the prism comprises three wedges, each made of glass manufactured by the Schott Group. In one exemplary embodiment, the three wedges are N-PSK57 glass, N-KZFS5 glass, and N-FK56 glass. In one exemplary embodiment, the refractive indices of the three wedges are 1.58700, 1.65412, and 1.48656, respectively. In another embodiment, the wedges may be made of materials from a list of glass manufacturers such as Ohara Corporation, Hoya Optical Corporation, and Sumitomo Electric Industries, Ltd. Each of these wedges may be made of a different material. In one embodiment, the wedges may be made of materials other than glass, such as plastic, ceramic, or other optical materials. Alternatively, the wedges may be made of two types of materials (M1 and M2), thus the three wedges are an M1 / M2 / M1 configuration. The higher the refractive index, the greater the dispersion; therefore, an achromatic prism utilizes a range of refractive indices to provide a range of dispersions, thereby balancing the system and reducing or eliminating chromatic aberration. In one embodiment, the materials used may include glass, plastic, and other optical materials.

[0034] In one embodiment, the achromatic prism 330 can be made by bonding the wedges together using an optically transparent adhesive material. In one embodiment, the achromatic prism 330 can be non-adhesive wedges placed close together. In one embodiment, as... Figure 3A As shown, the achromatic prism comprises three wedges. In one embodiment, these wedges are of different sizes.

[0035] Figure 3BThis is an illustration of another embodiment of a system with an achromatic prism. This configuration shows an achromatic prism 370 comprising four wedges. In one embodiment, the achromatic prism 370 may include two or more wedges.

[0036] Figures 4A to 4C This is an implementation of an achromatic prism. An achromatic prism is a prism designed to redirect light without causing the spectral separation (also known as chromatic aberration) that would occur with a standard lens.

[0037] The achromatic prism 410 is positioned at an angle to the optical axis of the projector 450 shown. In this configuration, the projector, being the output of the illumination and projection optics, directs light towards the achromatic prism 410. In one embodiment, the wedges 420, 430, and 440 of the achromatic prism 410 are displaced relative to each other, as shown. In one embodiment, the achromatic prism 410 can move the angle of light, thereby adjusting any compound angle to address the tilt and base angle tilt of the head-mounted display. This allows the light engine in the system to have different orientations with the waveguide's input coupler or other input elements, enabling the system to be mounted into an HMD form factor. In one embodiment, the specific material and material order constituting the wedges of the achromatic prism 410 are selected according to the construction of the HMD to which it is designed. This allows the structure of the invention to be adapted to various HMD constructions.

[0038] In one embodiment, the prism can be trimmed to produce trimmed achromatic prisms 460, 470. In one embodiment, the trimmed prism is trimmed based on the exit pupil of the optics used to ensure that the prism size is sufficient to capture a complete image. Trimming the top and bottom of the prism saves space and weight, both important considerations for head-mounted devices. Figure 4B and Figure 4C Two possible configurations for adjusting an achromatic prism are shown, with optical axes 465° and 475° illustrated. Those skilled in the art will understand that these are merely exemplary adjustment methods, and actual adjustments will be chosen based on image size and positional constraints.

[0039] Figure 5AThis is an illustration of one embodiment of a system with an achromatic prism having optical magnification. In this configuration, one or more wedges in the achromatic prism 530 are subjected to optical magnification. In one embodiment, this is achieved by setting curvature on the outer surface of the wedge to converge or diverge light. In one embodiment, optical magnification is provided by molding the wedge to have a curved surface. In another embodiment, a lens may be cemented to the prism to provide optical magnification. In this illustration, the first and third wedges are shown to have optical magnification. The curvature shown is exaggerated. In some embodiments, all wedges may have optical magnification. In some embodiments, only the two outer wedges may have optical magnification. In some embodiments, only one of these wedges may have optical magnification. Other configurations may be used. Figure 5B An embodiment is shown in which the wedges in the achromatic prism 535 all have optical magnification and are close to each other but do not touch.

[0040] Figure 5C This is an illustration of one embodiment of a system having a refractive / diffractive prism. In one embodiment, the prism may be a single prism, a refractive element having a diffractive surface, rather than having three or more wedges. In one embodiment, one or more wedges in an achromatic prism may be refractive / diffractive prisms. In one embodiment, prism 570 is a refractive element having a diffractive exit surface. In one embodiment, the diffractive exit surface may be formed by providing a diffraction grating on prism 570. In one embodiment, the diffraction grating may be a surface relief grating, a volume phase holographic grating, a digital planar holographic grating, or other gratings.

[0041] Figure 6 This is an illustration of one implementation of a system with a prism and a waveguide. In some implementations, the output of prism 630 is not directly output to the user's eyes. Instead, the output of prism 630 is the input to the waveguide. This allows the display 610 and optics 620 to be further moved from the position of image output 670. As shown, although the illumination and projection optics 620 are at an angle to the waveguide 640, those angles can be corrected by using prism 630, ensuring that light enters the input coupler 650 of the waveguide 640 at the correct angle and that the image output 670 through the output coupler 660 is not skewed. In one implementation, prism 630 can be a single prism. In another implementation, prism 630 can be any of the prisms discussed above, such as an achromatic prism, a refractive / diffractive prism, and / or may be subject to optical magnification. By using prism 630, light from an arbitrarily designed light engine can be guided while conforming to the constraints of the eyeglass shape.

[0042] Figure 7A This is an illustration of one embodiment of a system with two exit pupils using an achromatic prism. In one embodiment, display 710 generates light data that is transmitted through illumination and projection optics 720. The output of illumination and projection optics 720 is dichroic. These dichroic outputs are then directed to two or more prisms 730, 735 to produce image output 740. In one embodiment, prisms 730, 735 are separated by wavelength. In one embodiment, the optical bandwidth of each dichroic output is used when selecting the characteristics of the prisms used to construct the achromatic prism.

[0043] In one embodiment, each prism 730, 735 redirects a subset of colors from display 710. In one embodiment, for two prisms, one prism may be used for two colors (e.g., red and blue), while the other prism is used for the remaining color (e.g., green). In another embodiment, one prism may be used for two colors (red and green), and the other prism may also be used for two colors (blue and green). Other methods of distinguishing colors between prisms can be used. The light is then combined via waveguides or other elements for display.

[0044] Figure 7B This is an illustration of one embodiment of a system with laser illumination and two exit pupils. For the laser display 750, a single prism 770, 775 can be used for each color instead of an achromatic prism, because the narrow bandwidth of the laser light source mitigates chromatic aberration. Thus, prisms 770, 775 are used to redirect the light, not to correct chromatic aberration. In one embodiment, a full-color display can use three output pupils and prisms, with one output pupil and prism for each color of light.

[0045] Figure 8A and Figure 8B This is an illustration of one embodiment of a system with dichroic exit pupils. In this illustration, separate prisms for three colors are shown. Dichroic image data from illumination and projection optics 820 is transmitted to the three color prisms 830, 840, and 850. In one embodiment, the system includes a separate prism for each color. In one embodiment, as... Figure 8B As shown, prisms 830, 840, and 850 are arranged with displacement relative to each other. In one embodiment, the arrangement is three-dimensional, and these prisms can be displaced along all three dimensions. In one embodiment, the illumination source may not be coplanar, thereby the exit pupil will be at different positions relative to the optical engine.

[0046] Figure 9AThis is an illustration of one embodiment of a system with two exit pupils utilizing a waveguide. A display 910 generates image data, which is then output to two or three prisms 930, 940 via illumination and projection optics 920. The outputs of prisms 930, 940 are coupled into a waveguide 950. In one embodiment, the waveguide has a first input coupler 935 for color 1 and a second input coupler 945 for color 2. As described above, each of "color 1" and / or "color 2" can represent two colors; for example, color 1 could be red and blue, while color 2 is a green wavelength. The waveguide input couplers shown can be shifted along two axes. Waveguide 950 includes an output coupler 955 for coupling the combined image output to the user. Although... Figure 9A A separate input coupler for the outputs of the two prisms 930 and 940 is shown, but in another embodiment, the waveguide may have a single input coupler for input coupling of images from the two prisms.

[0047] Figure 9B This is an illustration of one embodiment of a system with two exit pupils utilizing two waveguides. A display 910 generates image data, which is then output to two or three prisms 930, 940 via illumination and projection optics 920. In this configuration, each prism 930, 940 has an associated waveguide 960, 970. In one embodiment, the input couplers 935, 945 of waveguides 960, 970 are biased against each other. In one embodiment, the output couplers 965, 975 are positioned above each other. In one embodiment, for a triangular prism system, there may be three separate waveguides. In another embodiment, for a triangular prism system, there may be two waveguides, one of which transmits data from two prisms.

[0048] In this way, the system can be adapted to various configurations of prisms and waveguides.

[0049] Figure 10 This is a flowchart of one implementation of a prism design system. The process begins at box 1010. At box 1020, the construction of the HMD used for the design is received. Figure 11A and Figure 11B An exemplary construction of HMD glasses is shown.

[0050] In frame 1030, the process determines the positions of the display engine and optics based on the HMD configuration, which for eyeglasses includes a glass lens and a frame. In one embodiment, the display engine is typically located in the temple, close to the lens. However, in some configurations, the display engine and / or optics may be moved further rearward along the temple, or may be located on the central portion of the frame or elsewhere. This defines the optical axes of the display engine and optics.

[0051] In box 1040, the composite angle between the optical axis and the image output position is calculated. In one embodiment, the image output position may be defined by the waveguide's input coupler. This composite angle can be calculated based on the base angle, the tilt angle, and the optical axis of the projection and the output of the intermediate optics box.

[0052] In box 1050, the process calculates the optimal prism configuration based on the compound angle to guide light from the optics to the display. In one embodiment, the prism configuration defines the angle variation and the choice of materials to avoid chromatic aberration. The prism configuration also includes any optical magnification applied to the prism. In one embodiment, the prism configuration includes the shape, size, and material of an achromatic prism. These aspects are selected based on the compound angle, the bandwidth of the light (i.e., a specific wavelength range), and the pupil size.

[0053] In box 1060, in one embodiment, the system determines the trimming of a prism to minimize its size. The prism can be trimmed to remove unused portions of the triangular prism.

[0054] In block 1070, in one embodiment, a custom prism is generated such that the positions of the light engine and optics are decoupled from the HMD fabrication. In one embodiment, the display engine, optics, and tailored prism are assembled with the HMD fabrication in block 1080 to realize an AR / VR HMD. The process then ends at block 1090. In this way, the process of the present invention allows the design to be adapted to a variety of HMD fabrications and constraints.

[0055] Figures 11A to 11B This is an illustration of one embodiment of eyeglasses using the system of the present invention. As shown, a pair of eyeglasses 1100 includes two arms 1110 coupled to a central portion 1115. The central portion 1115 supports two lenses. These lenses have a base angle 1160 and a tilt angle 1170. In one embodiment, the base angle is between 1 degree and 10 degrees. In one embodiment, the tilt angle is between 1 degree and 12 degrees. In one embodiment, the optical axis angle is between 0 degrees and 5 degrees.

[0056] The output of any augmented reality (AR) system is designed to match the composite displacement angle of the glasses. Generally, the display engine 1120 is positioned in each of the eyeglass arms 1110. Illumination and projection optics 1130 are positioned close to the display engine 1120. However, the actual image output is designed to be positioned on a waveguide 1150 within the eyeglass lens. Thus, as described herein, a prism 1140 is used to achieve the positioning of the output of the illumination and projection optics in the actual configuration of such glasses.

[0057] In the foregoing description, the invention has been described with reference to specific exemplary embodiments thereof. However, it will be apparent that various modifications and changes may be made to this disclosure without departing from the broader spirit and scope of the disclosure as set forth in the appended claims. Therefore, the description and drawings are to be considered illustrative rather than restrictive.

Claims

1. A display system for a head-mounted device including lenses, the display system comprising: A display area is located on the lens of the head-mounted device, the lens having a base angle and a forward tilt angle; Display engine and optics, the optics being used to generate images, the output of the optics having an optical axis; A prism for redirecting the output of the optics to the display area on the lens of the head-mounted device, taking into account the compound angle based on the base angle, the tilt angle, and the optical axis, the prism comprising a first prism for a first wavelength range and a second prism for a second wavelength range, wherein the first prism and the second prism are designed to resolve chromatic aberration within the corresponding wavelength range, and the construction of the first prism and the second prism is based on the compound angle, the wavelength range, and the pupil size.

2. The display system according to claim 1, wherein the prism is an achromatic prism.

3. The display system according to claim 2, wherein the achromatic prism comprises three wedges.

4. The display system according to claim 2, wherein the prism is trimmed.

5. The display system according to claim 1, wherein one of the first prism and the second prism is a refractive / diffractive prism having a refractive element and a diffraction exit surface.

6. The display system according to claim 5, wherein the incident surface of the prism is a refractive surface and the exit surface of the prism is a diffractive surface.

7. The display system according to claim 1, further comprising: A waveguide positioned close to the prism, wherein the prism is configured to direct the image to an input coupler of the waveguide, and the waveguide is configured to direct the output to the user.

8. The display system of claim 1, wherein the first wavelength range corresponds to a first color, and the second wavelength range corresponds to a second color.

9. The display system of claim 8, wherein the first color comprises red and blue, and the second color comprises green.

10. The display system of claim 8, wherein the prism includes a third prism for a third color.

11. The display system according to claim 8, further comprising: A first waveguide, wherein the first waveguide is used for the first color; and The second waveguide is used for the second color.

12. A display system for an augmented reality head-mounted device including lenses, the display system comprising: A waveguide, the waveguide including an input coupler and an output coupler, the output coupler including a display area located on the lens of the head-mounted device; Display engine and optics, the optics being used to generate images, the output of the optics having an optical axis; A prism for redirecting an image from the optics to the input coupler of the waveguide, taking into account the base angle, tilt angle, and composite angle of the output coupler. The prism includes a first prism for a first wavelength range and a second prism for a second wavelength range, wherein the first and second prisms are designed to resolve chromatic aberration, and the construction of the first and second prisms is based on the composite angle, the wavelength range, and the pupil size.

13. The display system according to claim 12, wherein the prism is an achromatic prism.

14. The display system of claim 13, wherein the achromatic prism comprises three wedges.

15. The display system of claim 12, wherein one of the first prism and the second prism is a refractive / diffractive prism, and the incident surface of the refractive / diffractive prism is a refractive surface, and the exit surface of the refractive / diffractive prism is a diffractive surface.

16. The display system of claim 12, wherein the wavelength range of the prism includes different colors.

17. The display system according to claim 16, further comprising: A waveguide comprising a plurality of waveguides for the different colors, wherein each of the plurality of prisms has an associated waveguide.

18. A display system for enhancing a head-mounted device, the display system comprising: arm; A lens having a base angle and a tilt angle; A waveguide located on the lens, the waveguide having an output coupler for displaying augmented reality images; Display engine and optics, the optics being used to generate images, the output of the optics having an optical axis; A prism for guiding the output from the optics to the input coupler of the waveguide at an angle altered with the optical axis, such that the image coupled to the output coupler is at the correct angle for display. The prism is designed to change the angle of the image based on a compound angle of the base angle, the tilt angle, and the optical axis. The prism includes a first prism for a first wavelength range and a second prism for a second wavelength range, wherein the first and second prisms are designed to resolve chromatic aberration, and the construction of the first and second prisms is based on the compound angle and the wavelength range.

19. A display system for a head-mounted device including lenses, the display system comprising: A display area is located on the lens of the head-mounted device, the lens having a base angle and a forward tilt angle; Display engine and optics for generating images, wherein the output of the optics has an optical axis; A prism for redirecting the output of the optics to the display area on the lens of the head-mounted device, taking into account the compound angle based on the base angle, the tilt angle, and the optical axis, the prism including an achromatic prism comprising three wedges, the prism including a first prism for a first wavelength range and a second prism for a second wavelength range, wherein the first prism and the second prism are designed to resolve chromatic aberration, and the construction of the first prism and the second prism is based on the compound angle and the wavelength range.

20. The display system of claim 19, wherein each of the three wedges has a different refractive index.

21. The display system of claim 19, wherein the three wedges are made of two materials having two different refractive indices in an M1 / M2 / M1 configuration.

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