Ophthalmic lens arrays for wafer-level assembly

Abstract

Embodiments of the present disclosure generally relate to augmented reality systems. More specifically, embodiments described herein provide for a waveguide with at least one ophthalmic lens, an augmented reality system, a method of fabricating waveguides with ophthalmic lenses, and an assembly for fabricating waveguides with ophthalmic lenses are shown and described herein.

Description

OPHTHALMIC LENS ARRAYS FOR WAFER-LEVEL ASSEMBLYBACKGROUNDField

[0001] Embodiments of the present disclosure generally relate to the field of augmented reality (AR) glasses. More specifically, embodiments described herein are methods of fabricating a plurality of lens assemblies each having a waveguide and a lens.Description of the Related Art

[0002] Virtual reality is generally considered to be a computer-generated simulated environment in which a user 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. Here, it is necessary for a waveguide assembly to have a waveguide coupled to a lens, such as an ophthalmic lens. It is desirable to fabricate waveguide assemblies on a mass scale.

[0004] Accordingly, what is needed in the art are methods of fabricating a plurality of lens assemblies.SUMMARY

[0005] In one embodiment, a method of fabricating a plurality of lens assemblies is provided. The method includes providing a waveguide substrate having a waveguide array or a waveguide segment of waveguides formed thereover andmolding an optical material to form a lens substrate having a lens array or a lens segment of lenses, disposing an adhesive material between each waveguide or over the waveguide array or waveguide segment of waveguides is disclosed and aligning the lens substrate with the waveguide substrate with each lens aligned with each waveguide, bonding the lens array to the waveguide array or the lens segment to the waveguide segment to form the plurality of lens assemblies with each lens assembly having a respective lens and a respective waveguide, and singulating each lens assembly from the plurality of lens assemblies.

[0006] In another embodiment, a method of fabricating a plurality of lens assemblies is provided. The method includes providing a waveguide substrate having a waveguide array of waveguides formed thereover and molding an optical material to form a lens substrate having a lens array of lenses. An adhesive material layer is formed between the lens array and the waveguide array, the material layer being a configuration that is one of a continuous adhesive gel and isolated adhesive locations adjacent air gaps. The lens substrate is aligned with the waveguide substrate with each lens aligned with each waveguide and bonding the lens array to the waveguide array to form the plurality of lens assemblies is provided with each lens assembly having a respective lens and a respective waveguide.

[0007] In another embodiment, a method of fabricating a plurality of lens assemblies is provided. The method includes providing a waveguide substrate having a waveguide array or a waveguide segment of waveguides formed thereover, molding an optical material to form a lens substrate having a lens array or a lens segment of lenses, disposing an adhesive material between each waveguide, aligning the lens substrate with the waveguide substrate with each lens aligned with each waveguide, bonding the lens array to the waveguide array or the lens segment to the waveguide segment to form the plurality of lens assemblies, each lens assembly having a respective lens and a respective waveguide with a gap defined by the respective lens, the respective waveguide, and the adhesive material having a refractive index of 1.0, and singulating each lens assembly from the plurality of lens assemblies.

[0008] In yet another embodiment, a mold tool is provided. The mold tool includes at least one channel to accommodate an influx of optical material and a plurality of lens molds in fluid communication with the at least one channel. The tool furtherincludes a plurality of dedicated inlets to independently support the fluid communication between the at least one channel and each of the lens molds of the plurality of lens molds.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] 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 scope, as the disclosure may admit to other equally effective embodiments.

[0010] Fig. 1A is a top view of a waveguide substrate according to embodiments described herein.

[0011] Fig. 1 B is perspective, frontal view of a waveguide of Fig. 1A according to embodiments described herein.

[0012] Figs. 1C and 1D are cross-sectional views of a waveguide substrate and a lens substrate according to embodiments described herein.

[0013] Figs. 2A and 2B are schematic, top views of mold tools according to embodiments described herein.

[0014] Fig. 3 is a flow chart of a method of fabricating a plurality of lens assemblies according to embodiments described herein.

[0015] Fig. 4 is a top view of a lens substrate according to embodiments described herein

[0016] 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

[0017] Embodiments of the present disclosure generally relate to the field of augmented reality (AR) glasses. More specifically, embodiments described herein are methods of fabricating a plurality of lens assemblies each having a waveguide and a lens. The lens may be an ophthalmic lens. The method of fabricating a plurality of lens assemblies includes providing a waveguide substrate having a waveguide array or waveguide segment of waveguides formed thereover, molding an optical material to form a lens substrate having a lens array or lens segment of lenses, disposing an adhesive material between each waveguide or over the waveguide array or waveguide segment of waveguides, aligning the lens substrate with the waveguide substrate with each lens aligned with each waveguide, bonding the lens array to the waveguide array or the waveguide segment to the lens segment to form the plurality of lens assemblies, each lens assembly having a respective lens and a respective waveguide, and singulating each lens assembly from the plurality of lens assemblies.

[0018] Fig. 1A is a top view of a waveguide substrate 120. The waveguide substrate 120 includes a plurality of waveguides 125 disposed over the waveguide substrate 120. The waveguides 125 are utilized for virtual, augmented, and / or mixed reality. The waveguides 125 may be formed in a waveguide array 124. The waveguide array 124 may have may have one or more waveguide segments 150. That is, with the waveguide substrate 120 intact, these segments may be cordoned off or otherwise marked in a manner that corresponds to accommodating different lens segments 450 as shown in Fig. 4. However, this is not required as the entire waveguide substrate 120 may be bonded with an entire lens substrate 100 as described below in advance of further processing and ultimate singulation.

[0019] Regardless of whether segmented or entire substrate-level bonding is employed, the waveguides 125 may ultimately be singulated from the waveguide substrate 120 after processing. E.g., the waveguide substrate 120 having a waveguide array 124 or a waveguide segment 150 of waveguides 125 are bonded to a lens substrate 100 having a lens array 182 or lens segment 450 of lenses 180 (further described in Figs. 1 C, 1D and Fig. 4). The bonded lenses 180 and waveguides 125 form waveguide assemblies 187. After bonding, the waveguide assemblies 187 are singulated such that each waveguide assembly 187 has a respective waveguide 125 and a respective lens 180.

[0020] Fig. 1B is a perspective frontal view of a waveguide 125. It is to be understood that the waveguides 125 described herein are exemplary waveguides 125 and that other waveguides 125 (such as waveguides having different arrangements of gratings) may be used. The waveguide 125 includes an input coupler 126 of structures and an output coupler 127 of structures disposed over the waveguide substrate 120 as shown in Fig. 1A. In some embodiments, the waveguide 125 also includes an intermediate grating 129, such as a pupil expansion grating or a fold grating.

[0021] Figs. 1C and 1D are cross-sectional views of a waveguide substrate 120 and a lens substrate 100 according to embodiments described herein are illustrated. The waveguide substrate 120 and the lens substrate 100 are bonded to one another. As shown in Fig. 1 C, an adhesive material 130 is disposed between waveguides 125 of the waveguide array 124 or the waveguide segment 150. This may include discrete locations of the adhesive material 130 adjacent air gaps 133. As shown in Fig. 1 D, an adhesive material 135 is disposed over the waveguide array 124 or the waveguide segment 150 in a more continuous manner, for example, in the form of a continuous gel absent the noted air gaps 133. The adhesive material 135 is further described herein. A lens substrate 100 includes lenses 180 that may be formed in a lens array 182 and / or may have one or more lens segments 450 of lenses 180 (e.g. see Fig. 4). For example, a row of 2-4 more lenses 180 may correspond to a lens segment 450. The lenses 180 may be ophthalmic lenes. The ophthalmic lenses may be planoconvex , concave, or a combination thereof. The lenses 180 include an optical material. The optical material is a plastic material. The plastic material includes polycarbonate, urethane, or a combination thereof.

[0022] The lens substrate 100 of Figs. 1C and 1D includes an array of lenses 180. These may be provided as a singular lens substrate 400 as depicted in Fig. 4. However, these may first be subdivided into different segments 450 of lens pluralities that are separately positioned over the waveguide substrate 120 and array 124. For example, rows of 2-4 or more lenses 180 may be provided as a single piece rows for bonding to the underlying unitary substrate-level array of waveguides 125 as described.

[0023] The lenses may be ophthalmic lenes. The ophthalmic lenses may be plano-convex , concave, or a combination thereof. For the embodiments of Figs. 1C and 1 D, uncut lens assembly arrays 101 are illustrated. More specifically, these arrays 101 include the noted waveguide substrate 120 and array 124 of Fig. 1A with the addition of a substrate-level array 182 of ophthalmic lenses 180 bonded thereto. Thus, instead of discretely separate, pick and place assembly of single lenses 180 to single waveguides 125, an entire lens assembly array 101 is provided that may be more efficiently cut or singulated as described further below. However, concave configurations may be employed or a lens array 101 such as that illustrated might be combined with an additional lens array below the waveguide substrate 120 in advance of cutting or singulating into a product for incorporation into an AR device.

[0024] Referring specifically to Fig. 1C, the adhesive material 130 between the waveguides 125 bonds the waveguides 125 with the lenses 180 to form lens assembly arrays 101 with air-gap between the waveguides 125 and the lenses 180. For example, a gap between a respective waveguide 125 and a bottom surface 185 of the respective lens 180 may have a refractive index of 1.0 (air). The adhesive material 130 located between the waveguides 125 may display a refractive index of about 1.9 or greater for sake of edge-blackening

[0025] Referring to Fig. 1 D, the adhesive material 135 is disposed between the waveguides 125 and the lenses 180. The adhesive material 135 is transparent or semi-transparent. The adhesive material 135 has a refractive index of about 1.6 or less. This may be advantageous for an embodiment such as this where the adhesive material 135 is more continuous and presents below a majority of the lens bottom surface 185 where it is prone to be in the ultimate field of view.

[0026] With the above uncut lens assembly arrays 101 in mind, it is of note that both embodiments (Figs. 1C or 1D) employ a unitary array 182 of lenses 180 as indicated. Further, each lens 180 of this array 182 includes a bottom surface 185 that is ultimately bonded to a waveguide 125 through a bond layer 140 or 145 as described. However, for each embodiment, notice that the depiction of discrete lenses 180 may be noted as 180 or 180'. The same is true for the bottom surfaces of each (e.g. 185 or 185'). This is not to infer that there is or isn’t any particular distinction from one lens 180 to another or from one bottom surface 185 to another. Rather, forthe illustrations provided, this is only meant to indicate that one lens 180 might be in one location of the lens array 182 and the other 180' might be at another, perhaps even a good distance away. The same may be true for the bottom surfaces in terms of location (e.g. 185 versus 185').

[0027] With the above in mind, the possibility exists that slightly different elevations may be present from one bottom surface location 185 to another 185'. This may be particularly true when considering the entirety of the lens substrate 100. However, as described below, each bottom surface 185 and 185' remains substantially level in and of itself at each lens location. Thus, bonding and overall structural integrity of each waveguide equipped lens (e.g. the waveguide assembly 187) may be ensured once singulated. This is due to the unique manner of molding of the lens array 182 as described herein which facilitates control over optical material uniformity at the bottom surface 185 of each respective lens 180 on a lens by lens basis.

[0028] Stated another way, consider the morphology of the lens substrate 100 across its entirety. For example, with specific reference to either Figs. 1C or 1 D, a bottom surface 185 of a lens 180 at one location to the left of the illustration might be of a given flatness level which may or may not substantially match the same flatness level at another location to the right of the illustration (e.g. between 180' and 185'). Nevertheless, the bottom surface 185 flatness level across each in individual lens 180 may be substantially uniform so as to ensure a structurally sound and level bonding between each lens 180 and underlying waveguide 125. As described below, this is due to a uniquely discrete manner of molding that is afforded to each individual lens 180 and bottom surface 185. So, for example, any potential levelness variations from one bottom surface 185 to another 185' may be rendered of negligible consequence in terms of achieving structural integrity in terms of bonding. That is, with each lens 180 (or 180') and bottom surface 185 (or 185') being independently molded, a discretely independent bonding or adhesive bead may be provided at each lens location. This is described in further detail below with respect to potential mold tools employed in achieving the illustrated lens array 182. Regardless, this may be of benefit when considering the possibility of warping or other potential deforming across any substrate surface during a cooling or settling process. Thus, instead of battling such a potentiality, such tendencies may be allowed for by ensuring a more localizedflatness is ensured for each lens 180 location due to the manner of molding that is discretely provided as described below.

[0029] Referring now to Fig. 2A, a schematic top view of an embodiment of a mold tool 200 is shown for fabrication of a plurality of lenses 180 as shown in Figs. 1C and 1 D. More specifically, an injection mold tool 200 is shown with a primary channel 240 leading to a host of side channels 245 directed at rows of discrete lens molds 280 separated by surrounding support structure 260. For the embodiment of Fig. 2A, the surrounding support structure 260 may accommodate some degree of injection mold influx so as to support an overall unitary lens substrate 100 as shown in Figs. 1C and 1 D. However, additional mold features may also be defined by the mold 200 illustrated in Fig. 2B.

[0030] Continuing with reference to Fig. 2A, notice that each lens mold 280 includes its own dedicated inlet 210 to ensure localized injection mold delivery. In this manner, a localized uniformity of material delivery may be ensured. So, for example, with added reference to Figs. 1C and 1D, while on the whole, across the entirety of the bottom surface 185 of the lens substrate 100 some degree variation in levelness may eventually result due to natural cooling, a degree of uniform levelness at each individual lens bottom surface 185 may nevertheless be assured.

[0031] For the embodiment illustrated in Fig. 2A, the primary channel 240 accommodates an influx of optical material (see arrow 220). Additionally, while injection molding is described here in reference to the illustrated mold tool 200, other material delivery options may be available so long as localized material delivery is employed as described. For example, techniques employing casing or compression molding may also be employed.

[0032] Continuing with reference to Fig. 2A, the mold 200 shown may be utilized in an over-molding technique where the depicted mold 200 is provided over a flat substrate. For example, a flat metal, ceramic or other suitable composite base may be provided to accommodate the mold tool 200 thereover in advance of the described material delivery. Once more, depending on the nature of the support base or the morphology of the mold tool 200 itself, additional mold features outside of the discrete lens molds 280 may be provided. For example, in one embodiment, intentionally scored or reduced material linear webs between the lens molds 280 may be found atthe surrounding support structure 260. Thus, with added reference to Figs. 1C and 1 D, an added degree of structural flexibility may be provided to the resulting lens substrate 100 so as to help ensure localized flatness and level bonding at each lens location (e.g. 180 or 180') irrespective of potential levelness disparity from one lens location to another (again, see 180 and 180 ).

[0033] Referring now to Fig. 2B, another top view embodiment of another mold tool 201 is illustrated. For this embodiment the mold tool 201 again defines discrete lens molds 280 as described above. However, the illustration and the tool 201 also present additional features which may be incorporated into another eventual lens substrate 400 (e.g. such as that depicted in Fig. 4). For example, gripper mold features 215 of the mold tool 201 may be provided to aid in subsequent alignment of the lens substrate 400 to an underlying waveguide substrate 120 as shown in Figs. 1 C and 1 D. Further, notice that for the embodiment of Fig. 2B, the flow of optical material (arrow 220) is through a more centrally located primary channel 240. Regardless, so long as dedicated inlets 210 are also provided as shown in Fig. 2A, discrete molding may be provided to support reliably robust fabrication as described hereinabove.

[0034] The flow of material through the primary channel 240 as illustrated in Fig.2B via arrow 220 continues through the mold tool 201 to support the forming of individual lenses 180 at lens molds 280 (see also Fig. 4). This flow ultimately continues through vents 247 and out of the mold tool 201 (see arrow 242). This may result in edge gates or other extrusion material readily sacrificed in advance of, or in conjunction with, the above described singulation.

[0035] With added reference to Fig. 4, the mold tool 201 of Fig. 2B also illustrates other potential features. For example, optical fiducial indentations 270 or datum indentations 217 for the development of fiducials 470 or datums 417 to mark alignment between a lens substrate 400 and underlying waveguide substrate 120 may be provided. Further, thru-holes 219 of the mold tool 201 may match thru-holes 419 of the lens substrate 400 for similar reasons.

[0036] Referring now to Fig. 3, a flow-chart summarizing an embodiment of manufacturing a plurality of lenses equipped with waveguide assemblies is shown. As indicated at operation 310, a substrate-level waveguide array is provided that is supported by a substrate. Thus, as noted at operation 325, a substrate-level lensarray may be molded. Once an adhesive has been applied to the waveguide array as indicated at operation 340, the substrate-level lens array may be aligned with the waveguide array below (see 355). Once alignment is achieved, a bonding may take place as indicated at operation 370. Therefore, singulation of waveguide equipped lens arrays may take place as indicated at operation 385. As a practical matter, this means that the more labor intensive, contaminant and / or damage prone technique for assembling waveguide equipped lens arrays may be avoided. Instead, a more efficient and product safe manner of assembly may be realized.

[0037] Referring now to Fig. 4, a top view of an embodiment of a lens substrate 400 is shown that might be used for singulation after alignment and bonding with a substrate level waveguide array as described above. This particular version of the lens substrate 400 may be formed from the mold tool 201 of Fig. 2B. Thus, while the Fig. 4 depiction is of a plurality of lenses 180, it largely resembles the depiction of this particular mold tool 201. So, for example, the illustrated gripper features 415 may be a result of the gripper mold features 215 shown in Fig. 2B. The same holds true for alignment aids such as optical fiducials 470 formed from indentations 270 or datums 417 formed from indentations 217 of the mold tool 201 of Fig. 2B. Of course, as described above, a beneficial aspect to the substrate level plurality of lenses 180 is the fact that whether a lens is at one location or another (see lens 180 vs. lens 180') minor intervening discrepancies in bottom surface flatness or levelness across the entirety of the substrate 400 may be of negligible consequence. This is due to the fact that the molding process through the mold tool 201 of Fig. 2B presents a discrete and dedicated material delivery on a location by location basis in the forming of each given lens 180 (and 180' alike).

[0038] Continuing with reference to the lens substrate 400 of Fig. 4, additional processing may take place once the lens substrate 400 is molded and available. For example, certain coatings may be added to the top exposed surface of the lenses 180. This may also be done to the more complete lens assembly array 101 level as illustrated in Figs. 1C and 1D. Regardless, this may include adding anti-reflective, anti-smudge, anti-fog, ultraviolet blocking, tints, photochromatic and / or other coating types in advance of the described singulating. Adding coatings in advance of singulating as described may improve product handling efficiencies. That is, providing a coating in a single step to a substrate-level article of manufacture may be muchmore efficient than repeatedly providing a coating to a singulated plurality of lenses, lens after lens after lens.

[0039] Embodiments described herein include combining arrays of waveguides and arrays of lens components in a manner that helps avoid certain manufacturing disadvantages where discrete and individual lens and waveguide assemblies are manufactured on a more one by one basis. Thus, manufacturing time is saved while also improving quality control. For example, material handling time and degree of manipulation is reduced thereby minimizing the potential for structural damage to the components. For these same reasons cleanliness may be increased and the risk of contaminant exposure decreased.

[0040] While the foregoing is directed to examples of the present disclosure, other and further examples 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 . A method of fabricating a plurality of lens assemblies, the method comprising:providing a waveguide substrate having a waveguide array or a waveguide segment of waveguides formed thereover;molding an optical material to form a lens substrate having a lens array or a lens segment of lenses;disposing an adhesive material between each waveguide or over the waveguide array or the waveguide segment of the waveguides;aligning the lens substrate with the waveguide substrate with each lens aligned with each waveguide;bonding the lens array to the waveguide array or the lens segment to the waveguide segment to form the plurality of lens assemblies, each lens assembly having a respective lens and a respective waveguide; andsingulating each lens assembly from the plurality of lens assemblies.

2. The method of claim 1 , wherein the lens segment of lenses includes two to four lenses.

3. The method of claim 1 , wherein the optical material is a plastic material.

4. The method of claim 3, wherein the plastic material includes polycarbonate, urethane, ora combination thereof.

5. The method of claim 1 , wherein the adhesive material has a refractive index of about 1.6 or less.

6. The method of claim 1 , wherein the adhesive material has a refractive index of about 1.9 or greater.

7. The method of claim 1 , wherein the respective waveguide has an input coupler and an output coupler.

8. The method of claim 1 , wherein the lenses are ophthalmic lenses.

9. A method of fabricating a plurality of lens assemblies, the method comprising: providing a waveguide substrate having a waveguide array or a waveguide segment of waveguides formed thereover;molding an optical material to form a lens substrate having a lens array or a lens segment of lenses;disposing an adhesive material between each waveguide;aligning the lens substrate with the waveguide substrate with each lens aligned with each waveguide;bonding the lens array to the waveguide array or the lens segment to the waveguide segment to form the plurality of lens assemblies, each lens assembly having a respective lens and a respective waveguide with a gap defined by the respective lens, the respective waveguide, and the adhesive material having a refractive index of 1.0; andsingulating each lens assembly from the plurality of lens assemblies.

10. The method of claim 9, wherein the lens segment of lenses includes two to four lenses.

11. The method of claim 9, wherein the optical material is a plastic material.

12. The method of claim 11, wherein the plastic material includes polycarbonate, urethane, ora combination thereof.

13. The method of claim 9, wherein the adhesive material has a refractive index of about 1.9 or greater.

14. The method of claim 9, wherein the respective waveguide has an input coupler and an output coupler.

15. The method of claim 9, wherein the lenses are ophthalmic lenses.

16. A mold tool, the mold tool comprising:at least one channel to accommodate an influx of optical material;a plurality of lens molds in fluid communication with the at least one channel; anda plurality of dedicated inlets to independently support the fluid communication between the at least one channel and each of the lens molds of the plurality of lens molds.

17. The mold tool of claim 16, wherein the lens molds correspond to ophthalmic lenses to be formed.

18. The mold tool of claim 16, further comprising at least one indentation outside of the plurality of lens molds to facilitate forming of a feature at a location of a lens array outside of lenses of the lens array.

19. The mold tool of claim 18, wherein the feature is one of a gripper feature and an alignment feature.

20. The mold tool of claim 19, wherein the alignment feature is one of a fiducial and a datum.

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