Notch filter to reduce eye glow and improve ar glasses brightness

Abstract

Embodiments of the present disclosure generally relate to augmented reality devices. More specifically, embodiments of the present disclosure relate to an augmented reality device with a waveguide and a light filter. The device includes a waveguide, the waveguide having a first surface and a second surface opposing the first surface, an incoupler to receive a projected image, and an outcoupler to project beams of the projected image to a user's field of view (FOV), a push lens, a pull lens; and a light filter disposed over the first surface of the waveguide and between the push lens and the pull lens, the light filter operable to reflect beams of the projected image on a path from the first surface back to the user's FOV.

Description

NOTCH FILTER TO REDUCE EYE GLOW AND IMPROVE AR GLASSES BRIGHTNESSBACKGROUNDField

[0001] Embodiments of the present disclosure generally relate to augmented reality devices. More specifically, embodiments of the present disclosure relate to an augmented reality device with a waveguide and a light filter.Description of the Related Art

[0002] Virtual reality is generally considered to be a computer generated simulated environment where a used has an apparent physical presence. A virtual reality experience can be generated in 3D and viewed with a head-mounted display (HMD), such as glasses or other wearable display devices that have near-eye display panels as lenses to display a virtual reality environment that replaces an actual environment.

[0003] Augmented reality, however, enables an experience in which a user can still see through the display lenses of the glasses or other HMD device to view the surrounding environment, yet also see images of virtual objects that are generated for display and appear as part of the environment. Augmented reality can include any type of input, such as audio and haptic inputs, as well as virtual images, graphics, and video that enhances or augments the environment that the user experiences. As an emerging technology, there are many challenges and design constraints with augmented reality.

[0004] The challenges include eye glow. Eye glow is the amount of visible light on the world side of the augmented reality device. Eye glow results in a distracting light projected on the world side of the augmented reality device. Accordingly, what is needed in the art are augmented reality devices having a waveguide with a light filter, which reduces the amount of eye glow projected on the world side of the augmented reality device.SUMMARY

[0005] In one embodiment, an optical device is disclosed. The optical device includes a projector, a projection filter disposed in a projection path of the projector, a waveguide, the waveguide having a first surface and a second surface opposing thefirst surface, an incoupler to receive a projected image, and an outcoupler to project beams of the projected image to a user’s field of view (FOV), a push lens, a pull lens; and a waveguide filter disposed over the first surface of the waveguide and between the push lens and the pull lens, the waveguide filter operable to reflect beams of the projected image on a path from the first surface back to the user’s FOV.

[0006] In another embodiment, an augmented reality device is disclosed. The augmented reality device including a projector, the projector configured to project at least one image, a projection filter disposed in a projection path of the projector, a waveguide, the waveguide having a first surface and a second surface opposing the first surface, an incoupler to receive a projected image, and an outcoupler to project beams of the projected image to a user’s field of view (FOV), at least one lens, and a waveguide filter, the waveguide filter disposed between the first surface of the waveguide and the at least one lens, the waveguide filter operable to reflect beams of the projected image on a path from the first surface back to the user’s FOV .

[0007] In another embodiment, an optical device is disclosed. The optical device including a projector, a waveguide, the waveguide having a first surface and a second surface opposing the first surface, an incoupler to receive a projected image, and an outcoupler to project beams of the projected image to a user’s field of view (FOV), a push lens, a pull lens, and a waveguide filter disposed over the first surface of the waveguide and between the push lens and the pull lens, the waveguide filter operable to reflect beams of the projected image on a path from the first surface back to the user’s FOV, wherein the waveguide filter is a notch filter or a light filter.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only exemplary embodiments and are therefore not to be considered limiting of its scope, and may admit to other equally effective embodiments.

[0009] Figure 1 is a perspective, frontal view of a waveguide, according to at least one embodiment.

[0010] Figure 2A is a schematic, side view of a first waveguide assembly including a green light filter in operation, according to at least one embodiment

[0011] Figure 2B is a schematic, side view of a second waveguide assembly including a red green blue (RGB) filter in operation, according to at least one embodiment.

[0012] Figure 2C is a schematic, side view of a third waveguide assembly including a projection filter and a waveguide filter in operation, according to at least one embodiment.

[0013] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.DETAILED DESCRIPTION

[0014] Embodiments of the present disclosure generally relate to augmented reality devices. More specifically, embodiments of the present disclosure relate to an augmented reality device with a waveguide and a light filter. The light filter may be a notch filter. The notch filter is a type of filter that controls frequencies of light that pass through the notch filter. In certain embodiments, the augmented reality device include an additional light filter disposed over a projector (e.g., a projection filter). Augmented reality devices include a user field of view (FOV). The user FOV is a point at which a user perceives the virtual images of an augmented reality display. The user FOV is determined by the angle of light reflected to the user’s eye from the outcoupler grating. The light projects content (e.g., an image or text) toward the user. Light exits the waveguide through the world side of the waveguide at the same angle it is projected into the waveguide by the incoupler. Light that exits the waveguide on the world side of the waveguide is referred to as eye glow. Eye glow can be seen by observers near the user. As described herein, light traveling through the waveguide is reflected back to the user’s FOV by a light filter. Reflecting the light traveling through the waveguide reduces the light that exits the waveguide on the world-side of the waveguide.

[0015] Figure 1 is a perspective, frontal view of a waveguide 100. It is to be understood that the waveguide 100 described herein is an exemplary waveguide and that other waveguides may be used with or modified to accomplish aspects of the present disclosure. The waveguide 100 includes a plurality of structures 102. The structures 102 may be disposed over, under, or on a first surface 105 or a second surface 103 of a substrate 101 , or disposed in the substrate 101. The structures 102 are nanostructures have a sub-micron critical dimension (e.g., a width less than 1 micrometer). Regions of the structures 102 correspond to one or more gratings 104. In one embodiment, which can be combined with other embodiments described herein, the waveguide 100 includes at least an incoupler 104A (e.g., an incoupler grating) and an outcoupler 104C (e.g., outcoupler grating). In another embodiment, which can be combined with other embodiments described herein, the waveguide 100 further includes an intermediate grating 104B. The intermediate grating 104B corresponds to a pupil expansion grating (“pupil expander”) or a fold grating.

[0016] In operation, the incoupler 104A receives incident beams of light having an intensity from a projector 218. The incident beams are split by the structures 102 into T 1 beams that have all of the intensity of the incident beams in order to direct a virtual image to the intermediate grating (if utilized) or to the outcoupler 104C. In one embodiment, which can be combined with other embodiments described herein, the T1 beams undergo total-internal-reflection (TIR) through the waveguide 100 until the T1 beams come in contact with the structures 102 of the intermediate grating. The structures 102 of the intermediate grating diffract the T1 beams to T-1 beams that undergo TIR through the waveguide 100 to the structures 102 of the outcoupler 104C. The structures 102 of the outcoupler 104C outcouple the T1 beams to the user’s eye. The T1 beams outcoupled to the user’s eye display the virtual image produced from the light engine from the user’s perspective and further increase the viewing angle from which the user can view the virtual image. In another embodiment, which can be combined with other embodiments described herein, the T1 beams undergo total- internal-reflection (TIR) through the waveguide 100 until the T1 beams come in contact with the structures 102 of the outcoupler 104C and are outcoupled to display the virtual image produced from the light engine.

[0017] The substrate 101 can be any substrate used in the art, and can be either opaque or transparent to a chosen wavelength of light, depending for the use of thesubstrate 101 as a substrate for a waveguide. Substrate selection may include substrates of any suitable material, including, but not limited to, amorphous dielectrics, non-amorphous dielectrics, crystalline dielectrics, polymers, or combinations thereof. In some embodiments, the substrate 101 includes, but is not limited to, a silicon-containing material, a silicon and oxygen containing compound, a germanium- containing material, a indium and phosphide containing compound, a gallium and arsenic containing compound, a gallium and nitrogen containing compound, a carbon- containing material, a silicon and carbon containing compound, a silicon, carbon, and oxygen containing compound, a silicon and nitrogen containing compound, a silicon, oxygen, and nitrogen containing compound, a niobium and oxygen containing compound, and lithium, niobium, and oxygen containing compound, an aluminum and oxygen containing compound, a indium, tin, and oxygen containing compound, a titanium and oxygen containing compound, a lanthanum and oxygen containing compound, a gadolinium and oxygen containing compound, a zinc and oxygen containing compound, a yttrium and oxygen containing compound, a tungsten and oxygen containing compound, a potassium, and oxygen containing compound, a phosphorous and oxygen containing compound, a barium and oxygen containing compound, a sodium and oxygen containing compound, or combinations thereof. In other embodiments, which can be combined with other embodiments described herein, the substrate 101 includes an oxide including one or more of gadolinium, silicon, sodium, barium, potassium, tungsten, phosphorus, zinc, calcium, titanium, tantalum, niobium, lanthanum, zirconium, lithium, or yttrium containing- materials. Example materials of the substrate 101 include silicon (Si), silicon monoxide (SiO), silicon dioxide (SiC>2), silicon carbide (SiC), fused silica, diamond, quartz germanium (Ge), silicon germanium (SiGe), indium phosphide (InP), gallium arsenide (GaAs), gallium nitride (GaN), sapphire, sapphire (AI2O3), lithium niobate (LiNbOs), indium tin oxide (ITO), lanthanum oxide (La20s), gadolinium oxide (Gd20s), zinc oxide (ZnO), yttrium oxide (Y2O3), tungsten oxide (WO3), titatium oxide (TiO2), zirconium oxide (ZrOs), sodium oxide (Na2O), niobium oxide (Nb20s), barium oxide (BaO), potassium oxide (K2O), phosphorus pentoxide (P2O5), calcium oxide (CaO), or combinations thereof.

[0018] The structures 102 may include a structure material. The structures 102 and the substrate 101 include a different material. The structure material includes,but is not limited to, one or more oxides, carbides, or nitrides of silicon, aluminum, zirconium, tin, tantalum, zirconium, barium, titanium, hafnium, lithium, lanthanum, cadmium, niobium, or combinations thereof. Example materials of the structure material include silicon carbide, silicon oxycarbide, titanium oxide, silicon oxide, vanadium oxide, aluminum oxide, aluminum-doped zinc oxide, indium tin oxide, tin oxide, zinc oxide, tantalum oxide, silicon nitride, zirconium oxide, niobium oxide, cadmium stannate, silicon oxynitride, barium titanate, diamond like carbon, hafnium oxide, lithium niobate, silicon carbon-nitride, silver, cadmium selenide, mercury telluride, zinc selenide, silver-indium-gallium-sulfur, silver-indium-sulfur, indium phosphide, gallium phosphide, lead sulfide, lead selenide, zinc sulfide, molybdenum sulfide, tungsten sulfide, or combinations thereof.

[0019] Figure 2A is a schematic, side view of a portion of a first waveguide assembly 200A including a green light filter 210 in operation. Figure 2B is a schematic, side view of a portion of a second waveguide assembly 200B including a red green blue (RGB) light filter 212 in operation. Figure 2C is a schematic, side view of a third waveguide assembly 200C including a projection filter 222 and a waveguide filter 220 disposed over a projector 218 and a waveguide filter 220 disposed over the waveguide 100 in operation. The projector 218 may be a light engine. The projection filter 222 may be a light filter or a notch filter. The waveguide filter 220 comprises a light filter or a notch filter. In one or more embodiments the projection filter 222 and the waveguide filter 220 comprise the same type of filter. Figure 2A Figure 2B, and Figure 2C show a user FOV 202 of the waveguide assembly (e.g., the first waveguide assembly 200A) and a world side 204 of the waveguide assembly (e.g., the first waveguide assembly 200A). As shown in Figure 2A, the first waveguide assembly 200A includes a waveguide 100 with at least a projector 218, an incoupler 104A, an outcoupler 104C, a green light filter 210, a push lens 206, and a pull lens 208. As shown in Figure 2B, the second waveguide assembly 200B includes a waveguide 100 with at least a projector 218, an incoupler 104A, an outcoupler 104C, a RGB light filter 212, a push lens 206, and a pull lens 208. As shown in Figure 2C, the third waveguide assembly 200C includes a waveguide 100 with at least a projector 218, an incoupler 104A, an outcoupler 104C, a projection filter 222, a waveguide filter 220, a push lens 206, and a pull lens 208. The waveguide filter 220 is operable to reflect beams of a projected image on a path from the first surface 105 back to the user’s FOV

[0020] In one or more embodiments, the first waveguide assembly 200A, the second waveguide assembly 200B, and the third waveguide assembly 200C includes the waveguide 100 and a light filter (e.g., a green light filter 210 or the RGB light filter 212) disposed (attached) between two lenses, a push lens 206 and a pull lens 208. For example, the light filter (e.g., a green light filter 210 or the RGB light filter 212) may be secured between two lenses with an optical adhesive (e.g., epoxy acrylic) or the light filter (e.g., a green light filter 210 or the RGB light filter 212) may be coated directly onto one or more of the lenses. The push lens 206 is disposed on top of the waveguide 100 (i.e., above the second surface 103). The pull lens 208 is disposed below the waveguide 100. For example, the light filter (e.g., a green light filter 210 or the RGB light filter 212) is disposed on the world side 204 of the waveguide 100. In one or more embodiments, the push lens 206 and the pull lens 208 have identical shapes. The push lens 206 and the pull lens 208 may be attached to the waveguide 100 using any suitable device that can be automated to adhere the lenses to the waveguide 100. For example, the waveguide 100 and the light filter (e.g., a green light filter 210 or the RGB light filter 212) may be laminated between the push lens 206 and the pull lens 208. Alternatively or additionally, a waveguide assembly includes a cover glass. For example, the light filter (e.g., a green light filter 210 or the RGB light filter 212) is disposed between the waveguide 100 and the cover glass (not pictured).

[0021] The first waveguide assembly 200A, the second waveguide assembly 200B, and the third waveguide assembly 200C use light to project at least one image 214 on the user FOV 202 of the waveguide assembly (e.g., the first waveguide assembly 200A). The at least one image 214 (e.g., light) is incoupled into the waveguide 100 via the incoupler 104A and are outcoupled via the outcoupler 104C. The at least one image 214 is projected from the projector 218 and results in at least one user image to be projected on the user FOV 202 of the waveguide 100. A majority of the outcoupled light is reflected to the user FOV 202 of the waveguide 100 as an image 214, which increases the brightness of the image 214 on the user FOV 202. For example, the brightness may increase from 1 % to 50% due to the outcoupled light reflection. A portion of the outcoupled light exits the waveguide 100 on the world side 204 of the waveguide 100 as eye glow 216. The color filter (e.g., a green light filter 210 or the RGB light filter 212) disposed between the two lenses (e.g., the push lens206 and the pull lens 208) allows for additional outcoupled light to reflect through the outcoupler on the user FOV 202 as the image 214 (e.g., the color filter reduces the amount of eye glow 216 on the world side 204). For example, a color filter (e.g., a green light filter 210 or the RGB light filter 212) may include up to an 85% reflectivity of light from the outcoupler.

[0022] As shown in Figure 2A, the green light filter 210 is disposed between the waveguide 100 and the push lens 206 (e.g., the green light filter 210 is laminated between the waveguide 100 and the push lens 206). The green light filter 210 is operable to reflect green light. The green light filter 210 includes a center wavelength of about 450 nm to about 620 nm. The spectrum bandwidth is about 20 nm to about 30 nm. The green light filter 210 includes an average optical density of about 6. The green light filter 210 includes -15 degrees to +15 degrees angular bandwidth. Additionally or alternatively, the angular bandwidth of the green light filter 210 mirrors the angular bandwidth of the user FOV. The green light filter 210 may include a dielectric material or a metal such as TiOx, SiOx, HfOx, Ag, Al, or Ti.

[0023] As shown in Figure 2B, the RGB light filter 212 is disposed between the waveguide 100 and the push lens 206 (e.g., the RGB light filter 212 is laminated between the waveguide 100 and the push lens 206). The RGB light filter 212 is operable to reflect all colors of light. The RGB light filter 212 includes a peak red center wavelength of about 635 nm, a peak green center wavelength of about 532 nm, and a peak blue center wavelength of about 457 nm. The RGB light filter 212 includes an optical density of about 4. The RGB light filter 212 includes about -3 to - 5 degrees angular bandwidth to about +3 to +5 degrees angular bandwidth. Additionally or alternatively, the angular bandwidth of the RGB light filter 212 mirrors the angular bandwidth of the user FOV. The RGB light filter 212 may include a dielectric material or a metal such as TiOx, SiOx, HfOx, Ag, Al, or Ti.

[0024] As shown in Figure 2C, the waveguide filter 220, which may comprise a RGB light filter 212 or a green light filter 210, is disposed between the waveguide 100 and the push lens 206 (e.g., the waveguide filter 220 is laminated between the waveguide 100 and the push lens 206). The waveguide filter 220 is operable to reflect various colors of light. In certain embodiments the waveguide filter 220 may include the RGB light filter 212 that includes a peak red center wavelength of about 635 nm,a peak green center wavelength of about 532 nm, and a peak blue center wavelength of about 457 nm. The RGB light filter 212 includes an optical density of about 4. The RGB light filter 212 includes about -3 to -5 degrees angular bandwidth to about +3 to +5 degrees angular bandwidth. Additionally or alternatively, the angular bandwidth of the RGB light filter 212 mirrors the angular bandwidth of the user FOV. The RGB light filter 212 may include a dielectric material or a metal such as TiOx, SiOx, HfOx, Ag, Al, orTi. In one or more embodiments, the waveguide filter 220 may include the green light filter 210 is operable to reflect green light. The green light filter 210 includes a center wavelength of about 450 nm to about 620 nm. The spectrum bandwidth is about 20 nm to about 30 nm. The green light filter 210 includes an average optical density of about 6. The green light filter 210 includes -15 degrees to +15 degrees angular bandwidth. Additionally or alternatively, the angular bandwidth of the green light filter 210 mirrors the angular bandwidth of the user FOV. The green light filter 210 may include a dielectric material or a metal such as TiOx, SiOx, HfOx, Ag, Al, or Ti.

[0025] As shown in Figure 2C, the projection filter 222, which may comprise a RGB light filter 212 or a green light filter 210 (e.g., the RGB light filter 212 or the green light filter 210 described above), is disposed between the projector 218 and the pull lens 208 (e.g., the projection filter 222 is disposed over the projector 218 on the waveguide 100 side of the third waveguide assembly 200C). In one or more embodiments, the projection filter 222 is disposed in the projection path of the projector 218. The projection filter 222 includes a band pass function that allows an image 214 to pass from the projection filter 222 to the waveguide 100. The emission spectrum of the image 214 passing though the projection filter 222 aligns with the emission spectrum of the image 214 reflecting back through the waveguide filter 220 and towards the user’s FOV. In one or more embodiments, the projection filter 222 and waveguide filter 220 comprise the same type of filter and / or the same material. Alternatively or additionally, the projection filter 222 and the waveguide filter 220 comprise a different filter and / or a different material.

[0026] The present disclosure provides a device to direct additional image reflection to the user side of the waveguide and limit eye glow. A light filter (e.g., a green light filter or the RGB light filter) is laminated between a push lens and the world side of a waveguide. In certain embodiments, a projection filter is disposed over theprojector. The projection filter is a light filter. The light filter is a notch filter. The notch filter is a type of filter that controls frequencies of light that pass through the notch filter. The light filter directs an image that is outcoupled from the outcoupler towards the user FOV of the waveguide, which increases the brightness of the image in the user FOV and reduces the eye glow on the world side of the waveguide.

[0027] While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

What is claimed is:1 . An optical device comprising: a projector; a projection filter disposed in a projection path of the projector; a waveguide, the waveguide having a first surface and a second surface opposing the first surface, an incoupler to receive a projected image, and an outcoupler to project beams of the projected image to a user’s field of view (FOV); a push lens; a pull lens; and a waveguide filter disposed over the first surface of the waveguide and between the push lens and the pull lens, the waveguide filter operable to reflect beams of the projected image on a path from the first surface back to the user’s FOV.

2. The optical device of claim 1 , wherein the waveguide filter is a notch filter.

3. The optical device of claim 1 , wherein the waveguide filter is a green color light filter.

4. The optical device of claim 1 , wherein the waveguide filter is a red green blue (RGB) color light filter.

5. The optical device of claim 1 , wherein the waveguide filter is laminated between the first surface of the waveguide and the push lens.

6. The optical device of claim 1 , wherein the projection filter is a green color light filter.

7. The optical device of claim 1 , wherein the projection filter is a red green blue (RGB) color light filter.

8. The optical device of claim 1 , wherein the projection filter and the waveguide filter are a same type of filter.

9. The optical device of claim 1 , wherein the projection filter and the waveguide filter are a different type of filter.

10. An augmented reality device comprising: a projector, the projector configured to project at least one image; a projection filter disposed in a projection path of the projector; a waveguide, the waveguide having a first surface and a second surface opposing the first surface, an incoupler to receive a projected image, and an outcoupler to project beams of the projected image to a user’s field of view (FOV); at least one lens; and a waveguide filter, the waveguide filter disposed between the first surface of the waveguide and the at least one lens, the waveguide filter operable to reflect beams of the projected image on a path from the first surface back to the user’s FOV .

11. The augmented reality device of claim 10, wherein the waveguide filter is a notch filter.

12. The augmented reality device of claim 10, wherein the waveguide filter is a green color light filter.

13. The augmented reality device of claim 10, wherein the waveguide filter is a red green blue (RGB) color light filter.

14. The augmented reality device of claim 10, wherein the at least one lens comprises a push lens and a pull lens.

15. The augmented reality device of claim 14, wherein the waveguide filter is laminated between the first surface of the waveguide and the push lens.

16. The augmented reality device of claim 10, wherein the projection filter is a green color light filter.

17. The augmented reality device of claim 10, wherein the projection filter is a red green blue (RGB) color light filter.

18. The augmented reality device of claim 10, wherein the projection filter and the waveguide filter are a same type of filter.

19. The augmented reality device of claim 10, wherein the projection filter and the waveguide filter are a different type of filter.

20. An optical device comprising: a projector; a waveguide, the waveguide having a first surface and a second surface opposing the first surface, an incoupler to receive a projected image, and an outcoupler to project beams of the projected image to a user’s field of view (FOV); a push lens; a pull lens; and a waveguide filter disposed over the first surface of the waveguide and between the push lens and the pull lens, the waveguide filter operable to reflect beams of the projected image on a path from the first surface back to the user’s FOV, wherein the waveguide filter is a notch filter or a light filter.

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