Optical component and manufacturing method thereof, and method for manufacturing optical structure at wafer level

Abstract

An optical wafer includes replicated optical elements (eg, lenses) that can be formed without the use of a separate glass or other substrate upon which the optical elements would otherwise need to be replicated or mounted.

Description

[0001] This application is a divisional application of the invention patent application with application date of June 14, 2019, application number 201980054636.5, and invention name “Optical element and chip including optical element”. Technical Field

[0002] The present disclosure relates to optical elements such as lenses, and wafers including the optical elements. Background Art

[0003] Smartphones and other handheld or portable devices sometimes include miniaturized optoelectronic modules, such as imaging devices and / or light projectors. Optoelectronic modules may employ optical assemblies that include lenses or other passive optical components stacked along the optical axis of the module to achieve the desired optical performance. In some applications, space is often at a premium. Therefore, it may be important for the module or optical assembly to maintain a relatively small overall z-height to achieve a compact module. Summary of the invention

[0004] The present disclosure describes methods for forming replicated optical elements, and optical wafers including replicated optical elements (e.g., lenses). The optical elements can be formed, for example, using a combined replication and vacuum infusion tool, and in some cases, the optical elements can be formed without using a separate glass or other substrate on which to replicate or mount the optical elements.

[0005] For example, in one aspect, a method of manufacturing an optical component includes providing a first polymer material on respective replication surfaces of a first tool and a second tool, bringing the first tool and the second tool toward each other so that the first polymer material on the replication surface of the first tool merges with the first polymer material on the opposite replication surface of the second tool, and then hardening the first polymer material to form a respective optical element having an optical surface based on the respective shape of the replication surface on which the first polymer is disposed. A second polymer material different from the first polymer material is injected into the space between the first tool and the second tool so that the second polymer material contacts the lateral side edges of the optical element. Subsequently, the second polymer material is hardened to form an optical component, the optical component including optical elements, each of which is laterally surrounded by the hardened second polymer material. The first tool and the second tool may then be removed from the optical component.

[0006] By eliminating the need for glass or other substrates on which to form the optical elements of the optical wafer, in some cases, the aforementioned techniques can result in a cheaper manufacturing process. In addition, in some cases, the resulting optical wafer can have a relatively small overall height.

[0007] In some embodiments, an optical assembly includes a stack of optical elements replicated on each other. For example, according to some embodiments, a method of manufacturing an optical assembly includes providing a first polymer material on corresponding replication surfaces of a first tool and a second tool, bringing the first tool and the second tool closer to each other so that the first polymer material on the replication surface of the first tool merges with the first polymer material on the opposite replication surface of the second tool, and then hardening the first polymer material to form a first group of optical elements having optical surfaces based on the corresponding shape of the replication surface on which the first polymer is disposed. The method also includes injecting a second polymer material different from the first polymer material into the space between the first tool and the second tool so that the second polymer material contacts the lateral side edges of the optical elements of the first group. Subsequently, the second polymer material is hardened. The second group of optical elements is directly or indirectly replicated on the optical elements of the first group, and a third polymer material is injected into the space between the lateral side edges of the optical elements of the second group. Then, the third polymer is hardened.

[0008] According to another aspect, a method for manufacturing optical structures at the wafer level includes providing a first polymer material on respective replication surfaces of a first tool and a second tool, bringing the first tool and the second tool closer together so that the first polymer material on the replication surface of the first tool merges with the first polymer material on the opposite replication surface of the second tool, and then hardening the first polymer material to form respective optical structures, each of the optical structures including an optical element and an enclosing portion that laterally surrounds the respective optical structure. A second polymer material different from the first polymer material is vacuum injected so that at least some of the vacuum-injected second polymer material contacts the lateral sides of the enclosing portion of the optical element. The method also includes continuing to apply a vacuum after injecting the second polymer material to remove a portion of the previously injected second polymer material and to leave a coating of the second polymer material on the lateral sides of each of the enclosing portions. Subsequently, the second polymer material is hardened to form optical structures, each of the optical structures including: one of the optical elements, a respective enclosing portion, and a coating on the lateral sides of the respective enclosing portion. Then, the first tool and the second tool are removed from the optical structure.

[0009] In some cases, the latter method includes removing the first tool from the optical structure and placing the carrier tape so that it is in contact with the optical structure while the second tool remains in contact with the optical structure. The second tool can then be removed from the optical structure.

[0010] The present disclosure also describes optical wafers and modules including optical elements.

[0011] Other aspects, features, and advantages will become apparent from the following detailed description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figures 1 to 3 Steps in a first process for forming an optical wafer including replicated optical elements are shown.

[0013] Figure 4 Shown by Figures 1 to 3 Cross-sectional view of an optical wafer produced by the process.

[0014] Figures 5 to 7 Steps in a second process for forming an optical wafer including replicated optical elements are shown.

[0015] Figure 8 Shown by Figures 5 to 7 Cross-sectional view of an optical wafer produced by the process.

[0016] Fig.9A Shows Figures 5 to 7 Variation of the process.

[0017] Fig. 9B Shown by Fig.9A Cross-sectional view of the optical wafer produced by the variant.

[0018] Fig. 9C Shows Fig. 9B A perspective view of an optical wafer.

[0019] FIG. 10A to FIG. 10M Steps in a third process for forming an optical wafer comprising optical elements replicated upon each other are shown.

[0020] Figures 11 to 14 Steps in a process for forming an optical structure are shown.

[0021] Fig.15 Shown by Figures 11 to 14 Examples of optical structures produced by the process. DETAILED DESCRIPTION

[0022] The present disclosure describes replicated passive optical elements, and the formation of optical wafers including replicated passive optical elements (e.g., lenses). Such optical wafers can be integrated into a wafer-level manufacturing process in which multiple optoelectronic modules are manufactured in parallel by forming a stack of optical devices and other wafers and then separating (e.g., by dicing) the stack into individual modules. Because the host device (e.g., a smartphone or other small mobile computing device) in which the optoelectronic module is disposed may have a limited z-height (i.e., thickness), reducing the overall thickness of the optoelectronic module may be an important consideration. Subsequently, reducing the thickness of the optical wafer is one way to help reduce the overall thickness of the module.

[0023] The following paragraphs describe techniques for forming an optical wafer that includes a plurality of replicated passive optical elements that are laterally separated from each other by partition walls that may be comprised, for example, of a material different from the optical element material (e.g., a non-transparent polymer). The passive optical elements may be operable to redirect light, for example, by refraction and / or diffraction and / or reflection, wherein each optical element is laterally surrounded by non-transparent material. Examples of such passive optical elements include lenses and prisms, as well as other diffractive or refractive structures. The passive optical elements and non-transparent materials may be formed, for example, using a combined replication and vacuum infusion tool, and may be formed without the use of a separate glass or other substrate on which these optical elements would otherwise need to be formed.

[0024] like Figure 1 As shown in the example of, a first tool 20A and a second tool 20B are held by glass or other carriers 22A, 22B, respectively. The tools 20A, 20B serve as combined replication and vacuum injection tools, as they are used to form replicated optical elements, as well as non-transparent vacuum injection areas of optical wafers. Each tool 20A, 20B has a corresponding replication surface 24A, 24B, which defines an area for replicating passive optical elements. In general, the shape of the replication surface includes "negatives" of the shape of the optical element to be formed. In the example shown, the replication surfaces 24A, 24B include concave cavities 26A, 26B for forming biconvex lenses. The precise shape of the replication surfaces 24A, 24B of the tools 20A, 20B may be different in other embodiments to facilitate the formation of optical elements having shapes different from the shape of the lenses in the example shown. Therefore, the shape of the replication surfaces 24A, 24B can be modified to facilitate the formation of lenses having convex or concave surfaces, as well as surfaces having other shapes. The shape of the replica surfaces 24A, 24B may be modified to facilitate forming other types of optical elements (eg, Fresnel lenses).

[0025] The concave cavities 26A of the first tool 20A are separated from each other by respective separation surfaces 28A of the tool 20A. In the example shown, the outer lateral edge 30A of each replication surface 24A protrudes slightly outward beyond the adjacent separation surface 28A to form a relatively sharp edge. Similarly, the concave cavities 26B of the second tool 20B are separated from each other by respective separation surfaces 28B of the tool 20B. In the example shown, the outer lateral edge 30B of each replication surface 24B protrudes slightly outward beyond the adjacent separation surface 28B to form a relatively sharp edge. In other embodiments, the lens tool may have different shapes for the replication surface.

[0026] like Figure 1As further shown, a small amount of material 32 ("lens material") for forming a passive optical element is deposited on each of the cavities 26A, 26B of the tools 20A, 20B. The lens material 32 may be, for example, a liquid epoxy or other polymer that, when hardened (e.g., cured), is transparent to a particular wavelength or range of wavelengths. The lens material 32 may be deposited, for example, by spraying the liquid epoxy onto the cavities 26A, 26B. The two tools 20A, 20B are then aligned using, for example, a photolithography machine.

[0027] After the tools 20A, 20B are aligned, they are brought into close proximity and contact with each other so that the lens material 32 on each particular cavity 26A of the first tool 20A is brought into close proximity and contact with the lens material 32 on the opposing cavity 26B of the second tool 20B, as shown in FIG. Figure 2 As shown. In some cases, one or both of the tools 20A, 20B have a spacer extending toward the opposing tool so as to maintain a specific distance between the two tools when the tools are in contact with each other. When the tools are brought close together, the lens materials 32 on each pair of opposing cavities 26A, 26B merge into a single volume 36 of lens material. The sharp edges 30A, 30B at the lateral boundaries of the replication surfaces 24A, 24B cause the liquid epoxy to laterally form a concave meniscus 34 around the volume 36 of lens material. After the meniscus 34 is developed, the liquid epoxy lens material is hardened, for example, by ultraviolet (UV) curing, thermal curing, or both. Each volume 36 of lens material thus forms a lens or other passive optical element. In this example, the lateral side edges of each optical element 36 have a concave shape at the interface with the surrounding material. The foregoing technique allows passive optical elements to be formed by double replication (i.e., simultaneously replicating two different surfaces of each optical element) in a single replication process.

[0028] Next, the space 38 between the opposing separation surfaces 28A, 28B of the tools 20A, 20B is filled with an epoxy or other polymer that is different from the material 32 used to form the optical elements 36. For example, preferably, the space 38 is filled with an epoxy or other polymer that, when hardened (e.g., cured), is substantially non-transparent (or significantly attenuates) light of a particular wavelength or range of related wavelengths. Examples of such polymer materials include epoxies, acrylates, polyurethanes, or silicones that contain non-transparent fillers (e.g., carbon black, pigments, or dyes). The non-transparent material can be injected into the space 38, such as by vacuum injection, while the tools 20A, 20B remain in place. The non-transparent vacuum injected material is then hardened (e.g., by UV curing, thermal curing, or both) to form non-transparent separation regions 40 that separate the previously formed passive optical elements 36 from each other, such as the optical elements 36 formed in the embodiment of the present invention. Figure 3 The tools 20A, 20B can then be removed to obtain the optical wafer 42 .

[0029] like Figure 4 As shown, the optical wafer 42 includes a plurality of passive optical elements 36 separated from each other by non-transparent regions 40. The non-transparent regions 40 are fused to adjacent optical elements and are therefore used to hold the optical elements 36 together in the optical wafer. Therefore, there is no need for a separate glass or other substrate on which lenses or other optical elements are formed. In addition, the non-transparent regions 40 serve as optical barriers or partitions between adjacent optical elements 36. In the example shown, the material constituting each of the optical elements 36 is the same throughout the thickness of the optical element (i.e., from its first optical surface 41A to its second optical surface 41B). In addition, in this example, each of the first optical surface 41A and the second optical surface 41B forms a corresponding interface with a fluid (e.g., air).

[0030] By eliminating the need for glass or other substrates on which to form optical elements 36, in some cases, the foregoing technique can result in a less expensive manufacturing process. In addition, the resulting optical wafer 42 can have a relatively small overall height. In some cases, this technique can also result in a smaller footprint for each optical element.

[0031] In some cases, one or both of tools 20A, 20B may be modified to include features that facilitate forming spacers or baffles extending from dividing wall 40 . Figure 5 An example is shown, which includes a first tool 120A and a second tool 120B. Tool 120A is similar to the above Figure 1 The tool 20A discussed above, except that the concave cavities 26A of the tool 120A are separated from each other by a separation surface having corresponding grooves 144A. Similarly, the tool 120B is similar to the tool 120B discussed above with respect to Figure 1 The tool 20B is discussed, except that the concave cavities 26B of the tool 120B are separated from each other by a separation surface having corresponding grooves 144B.

[0032] like Figure 5 As further shown, a small amount of material 32 ("lens material") for forming a passive optical element is deposited on each of the cavities 26A, 26B of the tools 120A, 120B. Here again, the lens material 32 can be, for example, a liquid epoxy or other polymer that, when hardened (e.g., cured), is transparent to a particular wavelength or range of wavelengths. The lens material 32 can be deposited, for example, by spraying the liquid epoxy onto the cavities 26A, 26B. The two tools 120A, 120B are then aligned using, for example, a photolithography machine.

[0033] After the tools 120A, 120B are aligned, they are brought into close proximity and contact with each other so that the lens material 32 on each particular cavity 26A of the first tool 120A is brought into close proximity and contact with the lens material 32 on the opposing cavity 26B of the second tool 120B, as shown in FIG. Figure 6 As shown. In some cases, one or both of the tools 120A, 120B have a spacer extending toward the opposing tool so as to maintain a specific distance between the two tools when the tools are in contact with each other. When the tools are brought close together, the lens material 32 on each pair of opposing cavities 26A, 26B merges into a single volume 36 of lens material. The sharp edges 30A, 30B at the lateral boundaries of the replication surfaces 24A, 24B cause the liquid epoxy to form a meniscus 34 laterally around the volume 36 of lens material. After the meniscus 34 is developed, the liquid epoxy lens material is hardened, for example, by UV curing, thermal curing, or both. Each volume 36 of lens material is thus formed into a lens or other passive optical element. The foregoing technique allows passive optical elements to be formed by double replication (i.e., simultaneously replicating two different surfaces of each optical element) in a single replication process.

[0034] Next, the space 138 between the opposing separation surfaces of the tools 120A, 120B (including the grooves 144A, 144B) is filled with an epoxy or other polymer that, when hardened (e.g., cured), is substantially non-transparent to a particular wavelength or range of wavelengths of interest. Examples of such polymer materials include epoxies, acrylates, polyurethanes, or silicones that contain non-transparent fillers (e.g., carbon black, pigments, or dyes). The non-transparent material can be injected into the space 138, such as by vacuum injection, while the tools 120A, 120B remain in place. The non-transparent vacuum injected material is then hardened (e.g., by UV curing, thermal curing, or both) to form non-transparent separation regions 140 that separate the passive optical elements 36 from each other, such as the optical elements 36 of FIG. 1 . Figure 7 Then, tools 120A, 120B can be removed to obtain optical wafer 142. Figure 8 As shown, the optics wafer 142 includes a plurality of passive optical elements 36 separated from one another by non-transparent regions 140, which also serve to hold the optical elements 36 together in the optics wafer.

[0035] As described above, a separate glass or other substrate is not required on which to form the lenses or other optical elements 36. The non-transparent areas 140 also serve as optical barriers or partitions between adjacent optical elements 36. In addition, these partitions 140 have one or more continuous protrusions 146, which can act as spacers or baffles. As described above, the spacer / baffle protrusions 146 can be formed as part of the same vacuum injection process used to form the partitions 140, and can be composed of the same material as the partitions.

[0036] although Figure 4 and Figure 8 Only a few optical elements 36 are shown in each of the 2D arrays, but the aforementioned techniques can be used to form optical wafers having tens, hundreds, or even thousands of optical elements 36 in a two-dimensional array. Each of the optical wafers 42, 142 can be attached to one or more other wafers (e.g., a printed circuit board on which active optoelectronic devices (such as light emitting or light sensing devices) are mounted) to form a wafer stack, which is subsequently cut into individual modules, each module including an optical assembly (which includes one or more optical elements 36) disposed on the optoelectronic device so that the optical element intersects the optical axis of the optoelectronic device.

[0037] In some cases, such as 9A to 9C As shown, the tools 22C, 22D may be provided with corresponding separation surfaces including additional grooves 144 that, when filled with a non-transparent epoxy or other polymer, form additional spacers or baffles 146 for adjacent optical elements 36. In this example, two spacers or baffles 146 separate each pair of adjacent optical elements 36. The optical wafer may then be integrated into a wafer stack, which is then cut into individual modules. Cutting may be performed between adjacent pairs of spacers or baffles 146 so that each of the resulting modules includes a spacer or baffle surrounding the optical element 36.

[0038] The foregoing techniques can be modified to accommodate the formation of optical wafers having two or more optical elements (e.g., lenses) stacked on each other. This technique allows, for example, the formation of doublets or triplets, such that the stacked optical elements fuse with each other. FIG. 10A to FIG. 10M A process for forming such a stacked optical element is shown.

[0039] FIG. 10A to FIG. 10C The steps shown can be combined with the above Figures 1 to 3 The discussion is substantially the same and illustrates the formation of a first array of replicated optical elements. Fig. 10A As shown, each of the first tool 220A and the second tool 220B includes a corresponding replication surface 224, which includes, for example, a concave cavity on which a transparent lens material (e.g., epoxy or other polymer) 232 is deposited. Fig. 10BAs shown, the first tool 220A and the second tool 220B are brought close to each other so that the lens materials 232 on the opposing cavities merge to form a single volume of lens material. As described above, sharp edges at the lateral boundaries of the replication surface 224 can be provided to cause the liquid epoxy to laterally create a meniscus around the volume of lens material, which is then hardened (e.g., by UV and / or thermal curing) to form optical elements 236. A second (e.g., non-transparent) epoxy or other polymer material is then injected into the spaces 238 between the optical elements 236 by vacuum injection. When hardened (e.g., by UV and / or thermal curing), the second material forms an optical barrier or partition wall 240 between adjacent optical elements 236, as shown in FIG. Fig. 10C Then, as Fig. 10D As shown, the upper tool 220A may be removed.

[0040] FIG. 10E to FIG. 10G The second array of replicated optical elements is shown formed directly on the first array of optical elements. Fig. 10E As shown, for example, a small amount of material 232A ("lens material") for forming a passive optical element is provided on each of the previously formed optical elements 236. The lens material 232A may be, for example, the same liquid epoxy or other polymer used in the previously formed optical elements 236, or may be a different epoxy or other polymer that, when hardened (e.g., cured), is transparent to a particular wavelength or range of wavelengths.

[0041] like Fig. 10E As shown, a third tool 220C, which also serves as a combined replication and vacuum injection tool, is positioned above the second tool 220B, and the two tools 220B, 220C are then aligned using, for example, a photolithography machine. In the example shown, the third tool 220C has a replication surface that defines a convex area 226A for replicating a second array of passive optical elements. However, the replication surface may have a different shape depending on the shape of the optical element to be formed.

[0042] After the tools 220B, 220C are aligned, they are moved relative to each other so that the lens material 232A on each optical element 236 in the first array contacts the relatively convex portion 226A of the replication surface of the third tool 220C, as shown. Fig.10FAs shown. One or both of the tools 220B, 220C may have a spacer extending toward the opposing tool so as to maintain a specific distance between the two tools when the tools are in contact with each other. When the tools are pressed together, the convex portion 226A of the replication surface of the third tool 220C is replicated in the lens material 232A. The lens material 232A is then hardened (e.g., by UV and / or thermal curing) to form the optical elements 236A of the second array. According to the aforementioned process, each of the replicated optical elements 236A in the second array is effectively adhered to a corresponding one of the replicated optical elements 236 in the first array, thereby forming an array of doublet lenses.

[0043] Next, the space 238A between the previously formed partition wall 240 and the opposing surface of the third tool 220C is filled with an epoxy or other polymer that, when hardened (e.g., cured), is substantially non-transparent to light of a particular wavelength or range of wavelengths (or significantly attenuates such light). Examples of such polymer materials include epoxies, acrylates, polyurethanes, or silicones that contain non-transparent fillers (e.g., carbon black, pigments, or dyes). Thus, the epoxy or other polymer material used to fill space 238A can be the same as or different from the epoxy or other polymer material used to fill space 238. The non-transparent material can be injected into space 238A, for example, by vacuum injection, while tools 220B, 220C remain in place. The non-transparent vacuum injected material is then hardened (e.g., by UV curing, thermal curing, or both) to form non-transparent partition regions 240A that separate the passive optical elements 236A from each other, such as the optical elements 236A of FIG. 2 . Figure 10G Each non-transparent region 240A is adjacent to an adjacent non-transparent region 240.

[0044] In some cases, tools 220B, 220C can then be removed to obtain an optical wafer that includes an array of doublet lenses 236, 236A separated from each other by non-transparent regions 240, 240A. Non-transparent regions 240, 240A also serve to hold the lenses together in the optical wafer. In addition, non-transparent regions 240, 240A serve as optical barriers or partitions between adjacent doublet lenses.

[0045] In some cases, the third array of replicated optical elements may be formed directly on the second array of optical elements 240A. FIG. 10H to FIG. 10K The third array of replicated optical elements is shown formed directly on the optical elements of the second array. Fig. 10H and Fig.10IAs shown, the third tool 220C is removed and a fourth tool 220D, which also serves as a combined replication and vacuum injection tool, is located above the second tool 220B. In the example shown, the fourth tool 220D is substantially the same as the first tool 220A, although it may be different in other embodiments. Thus, in the example shown, the fourth tool 220D has a replication surface that defines a concave cavity 226B for replicating a passive optical element (e.g., a convex lens). However, depending on the shape of the optical element to be formed, the replication surface of the fourth tool 220D may have a different shape.

[0046] like Fig.10I As further shown, a small amount of material 232B ("lens material") for forming a passive optical element is deposited on each of the cavities 226B of the fourth tool 220D, and on the upper concave surface of each of the lenses 236A. The lens material 232B may be, for example, the same liquid epoxy or other polymer used to form the previously formed optical element 236 (or 236A), or may be a different epoxy or other polymer that, when hardened (e.g., cured), is transparent to a particular wavelength or range of wavelengths. The two tools 220B, 220D are then aligned using, for example, a photolithography machine.

[0047] After the tools 20A, 20B are aligned, they are moved toward each other so that the lens material 232B on each specific cavity 226B of the fourth tool 220D is close to and in contact with the lens material 232 on the opposite upper concave surface of one of the lenses 236A, as shown in FIG. Fig.10J As shown. In some cases, one or both of the tools 220B, 220D have a spacer extending toward the opposing tool so as to maintain a specific distance between the two tools when the tools are close to each other. When the tools are close together, the lens material 232B in the specific cavity 226B and the lens material 232B on the opposite surface of one of the lenses 236A merge into a single volume 236B of lens material. The lens material is then hardened, for example, by UV curing, thermal curing, or both. Each volume 236B of lens material thus forms a lens or other passive optical element. According to the foregoing process, each of the replicated optical elements 236B in the third array is effectively adhered to a corresponding one of the replicated optical elements 236A in the second array, thereby forming an array of triple lenses.

[0048] Next, the space 238B between the previously formed partition wall 240A and the opposing surface of the fourth tool 220D is filled with an epoxy or other polymer that, when hardened (e.g., cured), is substantially non-transparent to light of a particular wavelength or a range of related wavelengths (or significantly attenuates such light). Examples of such polymer materials include epoxies, acrylates, polyurethanes, or silicones that contain non-transparent fillers (e.g., carbon black, pigments, or dyes). Thus, the epoxy or other polymer material used to fill the space 238B can be the same as or different from the epoxy or other polymer material used to fill the space 238 and / or the space 238A. The non-transparent material can be injected into the space 238B, for example, by vacuum injection, while the tools 220B, 220D remain in place. The non-transparent vacuum-injected material is then hardened (e.g., by UV curing, thermal curing, or both) to form non-transparent partition regions 240B that separate the passive optical elements 236B from each other, as shown in FIG. Figure 10K Each non-transparent region 240B is adjacent to an adjacent non-transparent region 240A.

[0049] The tools 220B, 220D may then be removed (see Fig.10L and Figure 10M ) to obtain an optical wafer 242, which includes a two-dimensional array of triple lenses 236, 236A, 236B separated from each other by non-transparent regions 240, 240A, 240B. The non-transparent regions 240, 240A, 240B are also used to hold the triple lenses together in the optical wafer. In addition, the non-transparent regions 240, 240A, 240B serve as optical barriers or partitions between adjacent triple lenses.

[0050] The exact shape of the replica surface of the tool can be varied from the examples shown to facilitate forming optical elements having shapes different from the shape of the lens in the examples shown. Thus, the shape of the replica surface of the tool can be modified to facilitate forming lenses having convex or concave surfaces, as well as surfaces having other shapes. The shape of the replica surface can be modified to facilitate forming other types of optical elements (e.g., Fresnel lenses).

[0051] The foregoing description describes an example of an optical wafer that includes an array of lenses, doublets, or triplets separated from one another by optical barriers or dividers composed of an epoxy or other polymer material that is different from the material of the lenses. The same process can be used to form one or more additional levels of optical elements on one or more previously formed arrays.

[0052] In each of the foregoing processes, the lens epoxy or other polymer for the optical element may be provided by jetting. Other techniques may also be used.

[0053] In some embodiments, after forming an array of replicated optical elements and before forming the next array of replicated optical elements, a thin coating with a relatively high refractive index is applied to the previously formed optical element. The coating can help increase optical power. In this case, the subsequently formed optical element is replicated directly on the coating, rather than directly on the previously formed optical element.

[0054] The compact optical wafers described herein can be integrated into, for example, a wafer stack, which is then diced into small pieces to form individual optoelectronic modules that can be installed in smartphones and other small mobile computing host devices such as tablets and personal digital assistants (PDAs). By eliminating the need for glass or other substrates on which the optical elements of the optical wafer are formed, the aforementioned techniques can, in some cases, result in a cheaper manufacturing process. In addition, the resulting optical wafer can have a relatively small overall height. The smaller height can result in, for example, a shorter camera stack that is flush with the surface of a smartphone or other computing device. In some cases, the technology can also result in a smaller footprint for each optical element.

[0055] In the foregoing examples, after the optical wafer is formed, or after the optical wafer is integrated into a wafer stack, the optical wafer (or wafer stack) is separated into individual lens units (or individual optoelectronic modules), for example, by dicing. The following paragraphs describe the formation of optical structures in a wafer-level process, in which multiple optical structures are formed simultaneously in parallel, but which do not need to be separated subsequently, for example, by dicing.

[0056] like Fig.11 As shown, the first tool 320A and the second tool 320B are held by glass or other carriers 322A, 322B, respectively. Tools 320A, 320B are used as combined replication and vacuum injection tools because they are used to form replicated optical elements, as well as non-transparent vacuum injection areas of optical wafers. Lens material 332 for forming passive optical elements is deposited on the replication surface of tools 320A, 320B. Here again, the lens material 332 can be, for example, a liquid epoxy or other polymer that is transparent to a specific wavelength or wavelength range when hardened (e.g., cured). The lens material 332 can be deposited, for example, by spraying liquid epoxy onto the replication surface (e.g., cavity) of the tool. In this case, the amount of lens material deposited on the replication surface can be greater than the relatively small amount used in the other embodiments described above. The two tools 320A, 320B are then aligned using, for example, a photolithography machine.

[0057] After the tools 320A, 320B are aligned, they are brought close to and in contact with each other so that the lens material 332 on the first tool 320A is brought close to and in contact with the lens material 332 on the opposite surface of the second tool 320B, as shown in FIG. Fig.12 In some cases, one or both of the tools 320A, 320B have a spacer extending toward the opposing tool to maintain a specific distance between the two tools when the tools are in contact with each other. When the tools are brought together, the lens material 332 on the opposing replication surfaces merges into a single volume 336 of lens material. Fig.12 Only the formation of a single optical element is shown, but many such optical elements can be formed in parallel on a wafer-scale. Preferably, the amount of lens material 332 initially disposed on the replication surface of the tool 320A, 320B should be sufficient to form (in addition to the lens) a lens yard 350 laterally surrounding the lens 336 when the tool presses the lens material 332, and a spacer region 352 laterally surrounding the lens yard 350. The spacer region 352 can laterally surround, for example, at least a portion of the side of the tool 320A, 320B. The lens material is then hardened (e.g., by UV and / or thermal curing).

[0058] Next, the space 328 between the opposing surfaces of the tool carriers 322A, 322B is filled with an epoxy or other polymer 340 (see FIG. 1 ) that is different from the material 332 used to form the optical element 336. Fig.13 ). For example, preferably, the space 328 is filled with an epoxy or other polymer that, when hardened (e.g., cured), is substantially non-transparent (or significantly attenuates) light of a particular wavelength or range of wavelengths of interest. Examples of such polymer materials include epoxies, acrylates, polyurethanes, or silicones containing non-transparent fillers (e.g., carbon black, pigments, or dyes). The non-transparent material can be injected into the space, such as by vacuum injection, while the tools 320A, 320B remain in place.

[0059] The flow of black epoxy or other polymer 340 is then turned off while maintaining the vacuum line. The vacuum washes away most of the black epoxy or other polymer 340, but leaves a small amount of black epoxy or other polymer as a coating 340A along the outer sidewalls of each lens element (i.e., on the lateral sides of the spacer region 352), as shown in FIG. Fig.14 The epoxy or other polymer 340 is then hardened (via UV and / or heat curing).

[0060] In some cases, tools 320A, 320B are removed from the resulting lens unit. Fig.15An example of which is shown in 360. However, in some cases, initially only one of the tools (e.g., upper tool 320A) is removed from the resulting lens unit. A carrier tape is placed on top of the lens unit before removing the second tool. The second (e.g., lower) tool 320B can then be removed from the lens unit. The carrier tape with multiple individual lens units mounted thereon can be provided, for example, to an integrated circuit manufacturer or other entity that uses pick-and-place equipment to integrate the individual lens units into a sensor or other module in a host device (e.g., a smartphone).

[0061] The sensor module including the lens unit can be mounted on a printed circuit board, for example. The printed circuit board can be a component of a host device such as a handheld communication or computing device (e.g., a mobile phone, a smart phone, a personal digital assistant (PDA) or a laptop computer). In some cases, the sensor module can be integrated into a small electronic device (e.g., a bio-device, a mobile robot, a surveillance camera, a portable camera, a laptop computer, and a tablet computer, etc.). For example, a smart phone may include a processor, a memory, an input / output device (including an interactive display), a communication interface and a transceiver, and other components. Various buses can be used to interconnect various components, and some components can be mounted on a common motherboard or otherwise as appropriate. The sensor module can also be interconnected to other components in the smart phone device, and in some embodiments, can be mounted on a common motherboard together with some other components.

[0062] Various modifications can be made within the spirit of the invention. Accordingly, other implementations are within the scope of the following claims.

Claims

1. A method for manufacturing an optical component, the method comprising: providing a first polymer material on respective replication surfaces of the first tool and the second tool; moving the first tool and the second tool toward each other so that the first polymer material on the replication surface of the first tool merges with the first polymer material on the opposing replication surface of the second tool; subsequently hardening the first polymer material to form a first set of optical elements having optical surfaces based on a corresponding shape of the replicated surface on which the first polymer is disposed; vacuum injecting a second polymeric material into the space between the first tool and the second tool such that the second polymeric material contacts the lateral side edges of the optical elements of the first set, and wherein the second polymeric material is different from the first polymeric material; continuing to apply the vacuum after injecting the second polymer material to remove a portion of the second polymer material previously injected; subsequently hardening the second polymer material; replicating an optical element of a second set on said optical element of said first set; and A third polymer material is vacuum injected into the spaces between the lateral side edges of the optical elements of the second set, and the third polymer is hardened.

2. The method according to claim 1, wherein: Each optical element of the second set is directly replicated on a corresponding optical element of the first set.

3. The method according to claim 1, further comprising: forming a coating on the optical elements of the first group; as well as The second set of optical elements is then replicated directly onto the coating.

4. The method according to claim 1, further comprising: replicating an optical element of a third group on said optical element of said second group; as well as A fourth polymer material is injected into the spaces between the lateral side edges of the optical elements of the third set, and the fourth polymer is hardened.

5. The method according to claim 4, wherein: Each optical element of the third set is directly replicated on a corresponding optical element of the second set.

6. An optical component manufactured using the method of claim 1, comprising: a plurality of replicated optical elements stacked upon one another, wherein each of the optical elements is fused to an adjacent one of the optical elements; wherein a side edge of a particular one of each of the optical elements is laterally surrounded by a corresponding first material that is different from a second material constituting the particular one of the optical elements, and wherein the first material and the second material are fused to each other.

7. The optical assembly according to claim 6, wherein: Each of the optical elements is a lens.

8. The optical assembly according to claim 6, wherein: Each of the optical elements has at least one optical surface that forms an interface with an optical surface of another of the optical elements.

9. The optical assembly according to claim 8, wherein: At least one of the optical surfaces has a shape that is different from a shape of another of the optical surfaces.

10. The optical assembly according to claim 8, wherein: At least one of the optical surfaces is convex and at least one of the optical surfaces is concave.

11. A method for manufacturing an optical structure at a wafer level, the method comprising: providing a first polymer material on respective replication surfaces of the first tool and the second tool; moving the first tool and the second tool toward each other so that the first polymer material on the replication surface of the first tool merges with the first polymer material on the opposing replication surface of the second tool; subsequently hardening the first polymer material to form respective optical structures, each of the optical structures comprising an optical element and a surrounding portion laterally surrounding the respective optical structure; vacuum injecting a second polymer material such that at least some of the vacuum injected second polymer material contacts lateral sides of the surrounding portion of the optical element, wherein the second polymer material is different from the first polymer material; continuing to apply the vacuum after injecting the second polymeric material to remove a portion of the second polymeric material previously injected and to leave a coating of the second polymeric material on the lateral sides of each of the enclosed portions; subsequently hardening the second polymer material to form the optical structures, each of the optical structures comprising: one of the optical elements, a corresponding surrounding portion, and the coating on the lateral sides of the corresponding surrounding portion; and The first tool and the second tool are removed from the optical structure.

12. The method according to claim 11, comprising: removing the first tool from the optical structure and placing a carrier tape in contact with the optical structure while the second tool remains in contact with the optical structure; as well as The second tool is then removed from the optical structure.

13. The method according to claim 11, wherein: At least one of the first polymeric material or the second polymeric material is a curable epoxy resin.

14. The method according to claim 11, wherein: The optical element is a lens.

15. A module comprising: an optoelectronic device having an optical axis; as well as The optical assembly according to any one of claims 6 to 10, which is arranged above the optoelectronic device and intersects the optical axis.

16. A handheld computing or communication device comprising: A module according to claim 15.

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