Polygonal tunable lens

Abstract

This invention relates to the field of tunable optical lens assemblies, specifically those featuring a polygonal outer shape, such as hexagonal design, to enhance efficiency in manufacturing and performance. These assemblies include a bendable transparent membrane, a deformable non-fluid lens body, and an actuator system for dynamically adjusting optical power. By optimizing the geometry of the outer frame, the invention maximizes packing density on wafers, minimizes material waste during production, and enables precise optical adjustments, making it suitable for advanced imaging, laser systems, and adaptive optics applications.

Description

[0001] 85144PC01

[0002] 1

[0003] POLYGONAL TUNABLE LENS

[0004] FIELD OF THE INVENTION

[0005] This present invention relates to the field of tunable optical lens assemblies. In particular, the present invention relates to a die comprising a first bendable transparent membrane, an actuator system and a rigid frame, having an outer shape enhancing efficiency in manufacturing and performance.

[0006] The present invention also relates to an optical lens assembly comprising a transparent, deformable, non-fluid lens body sandwiched between a first bendable transparent membrane and a second transparent back substrate forming a lens and an actuator system for applying forces to change an overall shape of the lens having an outer shape enhancing efficiency in manufacturing and performance.

[0007] BACKGROUND OF THE INVENTION

[0008] The development of tunable optical lenses has become increasingly important in fields such as imaging, medical devices, and advanced optical systems, where precise and adjustable focal lengths are essential.

[0009] Conventional tunable lenses often utilize square shapes for the outer frame, which can limit their packing density and result in significant material waste during production. Additionally, traditional designs may not fully optimize the relationship between optical power and the physical dimensions of the lens assembly. This creates challenges in manufacturing efficiency and increases production costs, especially when fabricating large quantities of lenses on a single wafer.

[0010] In this context, the present invention addresses these limitations by exploring polygonal outer shapes for the optical lens assembly.

[0011] Optimization in geometry not only improves packing density by reducing unused wafer surface area but also minimizes the total perimeter of the dies, which directly impacts dicing costs. By combining these geometric and functional optimizations, a balance between performance, cost- efficiency, and manufacturability, may be achieved.

[0012] Hence, by carefully selecting polygonal shapes that balance optical power, packing efficiency, and manufacturing cost, the invention enables high-performance lenses with reduced surface area waste, making them suitable for applications requiring both cost-effective production and high optical precision. 85144PC01

[0013] 2

[0014] OBJECT OF THE INVENTION

[0015] It is an object of the present invention to optimize the packing density of optical assemblies on a wafer.

[0016] A further object of the present invention is to reduce production costs.

[0017] In particular, it may be seen as an object of the present invention to optimize the packing density of optical assemblies on a wafer and reduce production costs by using a specific polygonal outer shape which minimize unused wafer surface area and minimize the perimeter of the dies, thereby decreasing the total length of dicing streets required during the manufacturing process.

[0018] It is a further object of the present invention to provide an alternative to the prior art.

[0019] SUMMARY OF THE INVENTION

[0020] The above-described objects and several other objects are intended to be obtained in a first aspect of the invention by providing a die comprising : a first bendable transparent membrane; an actuator system configured to exert forces on the first bendable transparent membrane; a rigid frame surrounding the first bendable transparent membrane, wherein the rigid frame is connected to the first bendable transparent membrane and to the actuator system.

[0021] The die has a polygonal outer shape.

[0022] In this context, the term "surrounding" refers to the frame's position relative to the first bendable transparent membrane, where the frame physically, and at least partially, encloses or borders the first bendable transparent membrane. Specifically, it means that the frame forms an external boundary around the first bendable transparent membrane, providing structural support and stability. The frame surrounding is thus positioned around the first bendable transparent membrane but not necessarily completely enclose it.

[0023] A die refers to the individual unit or component of an optical lens assembly that is fabricated on a larger substrate, typically a wafer. The wafer serves as the base material on which multiple dies are manufactured simultaneously.

[0024] In some embodiments, the rigid frame and the first bendable transparent membrane are shaped to match the polygonal outer shape. 85144PC01

[0025] 3

[0026] The polygonal outer shape may be configured to maximize a packing density (PD) by minimizing unused wafer surface area, thus allowing for the highest number of dies per wafer.

[0027] The polygonal outer shape may be configured to optimize the PD and to maximize the number of dies per wafer by achieving a minimum value of a figure of merit. The figure of merit may be defined as Perimeter / (Ri*PD), where Ri is a radius of an inscribed circle, for a die outer shape, of the polygonal outer shape and PD is the packing density and Perimeter is a perimeter of said die.

[0028] In some embodiment, the polygonal outer shape is a hexagonal outer shape. The above-described objects and several other objects are also intended to be obtained in a second aspect of the invention by providing an optical lens assembly comprising the die according to the first aspect of the invention and further comprising a second transparent substrate arranged opposite the first bendable transparent membrane; a transparent, deformable, non-fluid lens body positioned between the first bendable transparent membrane and the second transparent substrate.

[0029] The actuator system is configured to apply forces that dynamically adjust the curvature or shape of the transparent, deformable, non-fluid lens body relative an optical axis.

[0030] The rigid frame provides structural support to the optical assembly.

[0031] The rigid frame and the first bendable membrane and second transparent substrate are shaped to match the polygonal outer shape, therefore the optical assembly has a polygonal outer shape.

[0032] In this context, "match" refers to the functional and spatial relationship between components of the die, indicating that the shape of the first bendable transparent membrane and the rigid frame coincides due to fabrication constraints, while the second transparent substrate is configured to fit entirely within the boundaries defined by the polygonal outer shape of the rigid frame, regardless of whether its shape coincides with the frame.

[0033] The frame is connected to both the first bendable transparent membrane and the actuator system, ensuring the assembly's integrity and functionality during operation and dynamic adjustments.

[0034] In some further embodiments, the polygonal outer shape is configured to maximize, thus optimize, the optical power by achieving a minimum value of the figure of merit. 85144PC01

[0035] 4

[0036] Optimize is defined as adjusting or configuring the optical assembly to achieve the best possible performance or outcome under given constraints. It involves balancing competing factors to arrive at the most effective solution.

[0037] Packing density (PD) refers to the proportion of the wafer's total area that is occupied by the dies or usable space for optical assemblies as opposed to the unused spaces between them. In this context, optimizing PD means arranging the dies in a way that minimizes wasted wafer space, increasing the effective utilization of the wafer. A higher PD reduces production costs by maximizing the number of usable components from a single wafer.

[0038] Maximize the number of dies refers to an increase in the count of individual optical lens assemblies that can be fabricated on a single wafer.

[0039] By optimizing a specific figure of merit, a polygonal shape is identified minimizing unused spaces, or voids, between dies providing an optimized wafer layout, i.e. arranging dies in a pattern that fully utilizes the wafer's surface area, leaving minimal empty regions.

[0040] In some further embodiments, the polygonal outer shape is configured to minimize dicing costs and maximize optical power by optimizing the figure of merit.

[0041] Minimizing dicing costs refers to reducing the expenses associated with the dicing process, i.e. the step in which individual dies are separated from a larger wafer. This process involves cutting the wafer along predefined paths (dicing streets) to isolate each optical lens assembly.

[0042] Maximizing the optical power means optimizing the optical lens assembly to achieve the highest possible focusing ability or refractive strength for a given die. Optical power, measured in dioptres, is a function of the lens's curvature and material properties and directly impacts the lens's ability to bend light and focus it at a specific point.

[0043] By optimizing the figure of merit, a shape is identified allowing for better packing density and less wasted space, enabling more dies and thus, in turn more optical assemblies on a wafer while maintaining a large inscribed circle for higher optical power. 85144PC01

[0044] 5

[0045] In some embodiments, the figure of merit is defined as Perimeter / (Ri*PD), where Ri is a radius of an inscribed circle and PD is the packing density, and the Perimeter is a perimeter of the optical lens assembly.

[0046] In search for optimization of the packing density on a wafer while minimizing dicing costs and enabling production of high-performance lenses with reduced surface area waste, the inventors devised the invention through the analysis of a specific figure of merit being the Perimeter / (Ri*PD).

[0047] The Perimeter (P) is the perimeter of the die and is related to the total length of dicing streets. This parameter provides indications related to the cost of dicing. Ri is the radius of the incircle, i.e. the inscribed circle, which is approximately proportional to the optical power.

[0048] PD is the packing density, i.e. the ratio of the area occupied by dies to the total area.

[0049] When plotting the figure of merit versus the number of sides on the die of a regular polygonal shape, it appears clear, as shown in figure 2, that the figure of merit is minimal for two shapes: hexagonal and circular.

[0050] In that, in the context of optimizing the die surface and minimizing the perimeter, hexagonal and round shapes emerge as the most advantageous configurations. Both shapes offer efficient use of wafer space while reducing unnecessary material wastage.

[0051] There is a technological benefit in ensuring that no residual material is left on the wafer after dicing, thereby achieving a packing density of 100%. Residual wafer material can pose risks of contamination to the dies and potentially disrupt subsequent assembly processes. In that, leaving no material on the wafer after dicing eliminates the risk of contamination from loose material and helps maintain the integrity of the wafer surface, thereby simplifying further assembly processes. However, while both shapes excel in minimizing the perimeter, the hexagonal shape stands out for its superior packing density, higher optical power, and efficient material utilization. These advantages make the hexagonal configuration particularly suitable for high-volume, cost-sensitive manufacturing processes.

[0052] In some further embodiments, the optical assembly has a hexagonal outer shape, thereby providing minimized perimeter length relative to the optical power and the wafer surface area occupied by two or more optical assemblies. 85144PC01

[0053] 6

[0054] While the circular shape minimizes the perimeter relative to its area, it results in a slightly smaller inscribed circle compared to the hexagonal shape. This translates to reduced optical power for a given die size. Moreover, the circular shape does not achieve the same packing density as the hexagonal shape, leaving unused material between the dies. This inefficiency of the circular shape may lead to higher production costs and material waste during dicing.

[0055] Table 1

[0056] Table 1 shows the values of the figure of merit, as defined above, as a function of the shape of the optical assembly.

[0057] The radius Ri of the inscribe circle has been calculated according to the formula below of Table 2 and the ratio (Perimeter / Ri) for the circle is equal to 2K.

[0058] While both hexagonal and circle shape show the same figure of merit, as mentioned above, the hexagonal shape achieves optimal packing density due to its ability to tile perfectly without leaving gaps. 85144PC01

[0059] 7

[0060] Additionally, the hexagonal design minimizes material wastage during processing, as no significant space is left between the dies. The larger inscribed circle of the hexagon provides a greater effective optical power compared to the circular alternative, making it ideal for applications requiring high performance and costefficiency.

[0061] The rigid frame surrounding the optical assembly comprises rigid materials that provides structural integrity to the optical assembly, while allowing for dynamic deformation of the first bendable transparent membrane.

[0062] The frame's rigidity may serve several critical purposes such as structural support, preventing unwanted deformation, and minimize the stress on active components. In other embodiments, the polygonal outer shape is a hexagonal shape, and the optical assembly is configured to maximize PD by minimizing unused wafer surface area, thus allowing for the highest number of optical lens assemblies per wafer. 85144PC01

[0063] 8

[0064] This design leverages the geometric efficiency of hexagons to optimize PD on the wafer. This configuration significantly reduces the presence of unused regions between individual optical assemblies, thereby maximizing the effective use of the wafer's total area.

[0065] By minimizing the unused surface area, the hexagonal design facilitates the highest possible number of optical lens assemblies per wafer. This increase in packing density not only improves production efficiency but also reduces material costs associated with wafer processing. This in turn results in lower dicing costs and less material loss, further contributing to cost-effectiveness.

[0066] The hexagonal shape also supports a balance between compact die size and sufficient optical aperture size. The geometry provides an optimal compromise between minimizing the perimeter length, influencing the dicing efficiency, and maximizing the radius of the inscribed circle, correlated to the optical power. This balance ensures that each die offers robust optical performance while enabling higher yields during wafer production. Consequently, the hexagonal design is particularly advantageous in applications where both cost and performance are critical considerations.

[0067] In some other embodiments the PD is optimized by selecting a polygonal outer shape that allows for a higher number of dies per wafer while maintaining the required optical power for the lens assembly.

[0068] In some further embodiments, the actuator system is configured to dynamically adjust the curvature of the lens body within the polygonal frame by exerting forces on the first bendable transparent membrane to provide a tunable optical power.

[0069] This enables the optical assembly to achieve tunable optical power. This is accomplished through the precise application of ferees by the actuator system to the first bendable transparent membrane. These forces induce controlled deformation of the membrane, which, in turn, adjusts the curvature of the transparent, deformable, non-fluid lens body situated between the membrane and the opposing second transparent substrate.

[0070] The first, the second and other aspects or embodiments of the present invention may each be combined with any of the other aspects and embodiments. These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter. 85144PC01

[0071] 9

[0072] BRIEF DESCRIPTION OF THE FIGURES

[0073] The optical lens assembly according to the invention will now be described in more detail with regard to the accompanying figures. The figures show one way of implementing the present invention and is not to be construed as being limiting to other possible embodiments falling within the scope of the attached claim set.

[0074] Figures la and lb are schematic drawings of an optical lens assembly according to some embodiments of the invention.

[0075] Figure 2 is a plot showing the Figure of merit as a function of the number of sides of the die having the shape of a regular polygon.

[0076] Figure 3 is a schematic drawings of an optical lens assembly according to some embodiments of the invention, showing membrane displacement of an optical assembly having hexagonal shape.

[0077] DETAILED DESCRIPTION OF EMBODIMENTS

[0078] Figures la is a schematic top view drawing of an optical lens assembly 5 having hexagonal shape.

[0079] Figures lb is a schematic bottom view drawing of an optical lens assembly 5 having hexagonal shape.

[0080] The optical lens assembly 5 comprises a frame 1, a first bendable transparent membrane 2, a transparent deformable non-fluid lens body 3, a second transparent substrate 4 and an actuator system 8.

[0081] The circular aera shown in the middle of the first membrane is the transparent area, not shadowed by the actuator system 8, allowing light transmittance through the lens.

[0082] Figure 2 is a plot 9 showing the Figure of merit as a function of the number of sides of the die being a regular polygon.

[0083] Clearly, it can be noticed that the hexagonal shape 6 represents a surprising minimum in the figure of merit indicating the optimal shape for minimizing dicing costs and maximizing optical power. Indeed, while both hexagonal 6 and circular shape 7 show the same figure of merit, the hexagonal shape 6 achieves optimal packing density due to its ability to tile perfectly without leaving gaps.

[0084] Figure 3 is a schematic drawing of an optical lens assembly 10 showing membrane displacement of an optical assembly having hexagonal shape. 85144PC01

[0085] 10

[0086] The membrane displacement in figure 3 is shown with a scale bar for the Z- displacement in |_im.

[0087] Although the present invention has been described in connection with the specified embodiments, it should not be construed as being in any way limited to the presented examples. The scope of the present invention is set out by the accompanying claim set. In the context of the claims, the terms "comprising" or "comprises" do not exclude other possible elements or steps. Also, the mentioning of references such as "a" or "an" etc. should not be construed as excluding a plurality. The use of reference signs in the claims with respect to elements indicated in the figures shall also not be construed as limiting the scope of the invention. Furthermore, individual features mentioned in different claims, may possibly be advantageously combined, and the mentioning of these features in different claims does not exclude that a combination of features is not possible and advantageous.

Claims

85144PC0111CLAIMS1. A die comprising:- a first bendable transparent membrane;-an actuator system configured to exert forces on said first bendable transparent membrane;- a rigid frame surrounding said first bendable transparent membrane, wherein said rigid frame is connected to said first bendable transparent membrane and to said actuator system; characterized in that, said die has a polygonal outer shape, wherein said polygonal outer shape is configured to optimize said packing density (PD) and to maximize the number of dies per wafer by achieving a minimum value of a figure of merit and wherein said figure of merit is defined as Perimeter / (Ri*PD), where Ri is a radius of an inscribed circle of said polygonal outer shape and PD is said packing density and Perimeter is a perimeter of said die.

2. An die according to claim 1, wherein said rigid frame and said first bendable transparent membrane are shaped to match said polygonal outer shape.

3. A die according to any of the preceding claims, wherein said polygonal outer shape is configured to maximize a packing density (PD) by minimizing unused wafer surface area, thus allowing for the highest number of dies per wafer.

4. An die according to any of the preceding claims, wherein said polygonal outer shape is a hexagonal outer shape.

5. An optical lens assembly comprising said die according to any of the preceding claims, further comprising:- a second transparent substrate arranged opposite said first bendable transparent membrane;- a transparent, deformable, non-fluid lens body positioned between said first bendable transparent membrane and said second transparent substrate; wherein said actuator system is configured to apply forces that dynamically adjust the curvature or shape of said transparent, deformable, non-fluid lens body relative an optical axis;85144PC0112 wherein said rigid frame provides structural support to said optical assembly; and wherein said rigid frame and said first bendable membrane and second transparent substrate are shaped to match said polygonal outer shape.

6. An optical lens assembly according to claim 5, wherein said polygonal outer shape is configured to maximize optical power by achieving a minimum value of said figure of merit.

7. An optical lens assembly according to any of the preceding claims 5-6, wherein said polygonal outer shape of said optical lens assembly is a hexagonal outer shape.

8. An optical lens assembly according to any of the preceding claims 5-7, wherein said rigid frame provides structural integrity to the optical assembly while allowing for dynamic deformation of said first bendable transparent membrane.

9. An optical lens assembly according to any of the preceding claims 5-8, wherein said packing density (PD) is optimized by selecting a polygonal outer shape that allows for a higher number of dies per wafer while maintaining the required optical power for said optical lens assembly.

10. An optical lens assembly according to any of the preceding claims 5-9, wherein said actuator system is configured to dynamically adjust a curvature of said non-fluid lens body within said rigid frame by exerting forces on said first bendable transparent membrane to provide a tunable optical power.

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