Method and apparatus for casting polymer product

Abstract

To provide an optical polymer film and a method for producing the film.SOLUTION: In an example method of forming a waveguide part having a predetermined shape, a photocurable material is dispensed into a space between a first mold portion and a second mold portion opposite the first mold portion. A relative separation between a surface of the first mold portion with respect to a surface of the second mold portion opposing the surface of the first mold portion is adjusted to fill the space between the first and second mold portions. The photocurable material in the space is irradiated with radiation suitable for photocuring the photocurable material to form a cured waveguide film so that different portions of the cured waveguide film have different rigidity. The cured waveguide film is separated from the first and second mold portions. The waveguide part is singulated from the cured waveguide film.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of U.S. Provisional Application No. 62 / 746,414, filed October 16, 2018, the disclosure of which is incorporated herein by reference in its entirety.

[0002] FIELD OF THE DISCLOSURE The present disclosure relates to optical polymer films and methods for producing same. [Background technology]

[0003] An optical imaging system, such as a wearable imaging headset, can include one or more eyepieces that present a projected image to a user. The eyepieces can be constructed using one or more thin layers of highly refractive materials. As an example, the eyepieces can be constructed from one or more layers of highly refractive glass, silicon, metal, or polymer substrates.

[0004] In some cases, the eyepiece can be patterned (e.g., with one or more optically diffractive nanostructures) to project an image according to a particular depth of focus, e.g., to a user viewing the patterned eyepiece, the projected image can appear to be at a particular distance away from the user.

[0005] Additionally, multiple eyepieces can be used together to project a simulated three-dimensional image. For example, multiple eyepieces, each with a different pattern, can be layered on top of each other, with each eyepiece projecting a different depth layer of the volumetric image. Thus, the eyepieces can collectively present a volumetric image across three dimensions to a user. This can be useful, for example, in presenting a "virtual reality" environment to a user.

[0006] To improve the quality of the projected image, the eyepiece can be constructed such that unintentional variations in the eyepiece are eliminated or otherwise reduced. For example, the eyepiece can be constructed so that it does not exhibit any wrinkles, uneven thickness, or other physical distortions that may adversely affect the performance of the eyepiece. Summary of the Invention [Means for solving the problem]

[0007] Systems and techniques for producing polymer films are described herein. One or more of the described implementations can be used to produce polymer films in a highly precise, controlled, and reproducible manner. The resulting polymer films can be used in a variety of variation-sensitive applications where extremely tight tolerances on film dimensions are desired. For example, the polymer films can be used in optical applications (e.g., as part of an eyepiece in an optical imaging system) where material homogeneity and dimensional constraints are on the order of optical wavelengths or smaller.

[0008] Generally, polymer films are produced by encapsulating a photocurable material (e.g., a photopolymer or photoactivated resin that hardens when exposed to light) between two molds and curing the material (e.g., by exposing the material to light and / or heat). Furthermore, a "singulation" process can be performed to separate the polymer film into multiple different products (e.g., by cutting the polymer film one or more times to obtain separate products with specific sizes and shapes) and / or to remove excess polymer material from the edges of the polymer products.

[0009] In some cases, performing a singulation process may introduce undesirable variations in the polymer film, making the resulting product less suitable for use in a variation-sensitive environment. For example, singulation is sometimes performed using techniques such as die-cutting, milling, water-jet cutting, ultrasonic cutting, or laser cutting to separate the polymer film into different parts. However, if the polymer film is too brittle, it may crack or chip when cut, resulting in poor edge quality. These imperfections may adversely affect the production process (e.g., because it is more difficult to make accurate and precise cuts during production) and reduce yields in applications that require high-precision edges. Furthermore, these imperfections may make the resulting polymer products less suitable for their intended use. For example, the chips or cracks may interfere with the intended optical properties of the polymer product, adversely affecting the performance of the polymer product. As another example, this may generate debris that may damage the polymer product and / or make it difficult to stack the polymer products together with a high degree of precision (e.g., in a multi-optical device). Furthermore, these imperfections can increase the variability of the polymer product from production to production, and therefore may make the polymer product less suitable for use in applications that are sensitive to variability.

[0010] Exemplary techniques for singulating polymer films are described herein. One or more of the described techniques can be implemented to separate the polymer film into multiple different products while eliminating or otherwise reducing the occurrence of unintentional chips or cracks. Thus, polymer products can be produced more efficiently, consistently, and accurately.

[0011] In one aspect, a method of forming a waveguide section having a predetermined shape includes dispensing a photocurable material into a space between a first mold section and a second mold section opposite the first mold section, adjusting a relative separation between a surface of the first mold section to a surface of the second mold section opposite the surface of the first mold section to fill the space between the first and second mold sections. The method also includes irradiating the photocurable material in the space with radiation suitable to photocuring the photocurable material and forming a cured waveguide film such that different portions of the cured waveguide film have different stiffnesses. The method also includes separating the cured waveguide film from the first and second mold sections and singulating waveguide sections from the cured waveguide film. The waveguide sections correspond to portions of the cured waveguide film having a higher stiffness than other portions of the cured waveguide film.

[0012] Implementations of this aspect can include one or more of the following features.

[0013] In some implementations, different portions of the photocurable material can be irradiated with different amounts of radiation. The portions of the photocurable material irradiated with a higher dose of radiation can correspond to portions of the cured waveguide film that have a higher stiffness than portions of the waveguide film irradiated with a lower dose of radiation. The different amounts of radiation can be provided by irradiating the space through a mask. The mask can include openings that correspond to the predetermined shape of the waveguide portion.

[0014] In some implementations, the waveguide section has a thickness of 1,000 μm or less and a width of at least 1 cm 2 and

[0015] In another aspect, a method of forming a waveguide section having a predetermined shape includes dispensing a photocurable material into a space between a first mold section and a second mold section opposite the first mold section, adjusting a relative separation between a surface of the first mold section to a surface of the second mold section opposite the surface of the first mold section to fill the space between the first and second mold sections. The method also includes irradiating the photocurable material in the space with radiation suitable to photocuring the photocurable material to form a cured waveguide film. The method also includes separating the cured waveguide film from the first and second mold sections to provide a waveguide section, singulating a portion of the cured waveguide film in the predetermined shape from the cured waveguide film, and annealing the singulated portion to provide a waveguide section. The waveguide section has a stiffness greater than a stiffness of the cured waveguide film.

[0016] Implementations of this aspect can include one or more of the following features.

[0017] In some implementations, the singulated portions can be annealed by irradiating the singulated portions with appropriate radiation to photo-harden the photo-hardenable material.

[0018] In some implementations, the singulated portion can be annealed by heating the singulated portion.

[0019] In some implementations, the waveguide section has a thickness of 1,000 μm or less and a width of at least 1 cm 2 and

[0020] In another aspect, a method of forming a waveguide section having a predetermined shape includes positioning a frame between a first mold part and a second mold part, the frame having a rigidity, the frame defining a first opening having a predetermined shape, and dispensing a photocurable material into the opening of the frame. The method also includes irradiating the photocurable material in the opening with radiation suitable to photocur the photocurable material to form a hardened waveguide film having a rigidity different from the rigidity of the frame, and separating the hardened waveguide film from the first and second mold parts. The method also includes singulating the waveguide section from the hardened waveguide film by cutting a path along the frame. The path at least partially surrounds the opening. The method also includes extracting the waveguide section including the hardened photocurable material from the frame along the path.

[0021] Implementations of this aspect can include one or more of the following features.

[0022] In some implementations, the frame can define a plurality of openings, each having a predetermined shape. The photocurable material can be dispensed into each of the openings of the frame. The photocurable material in each of the openings can be simultaneously irradiated with radiation. The cured waveguide film can include the photocurable material cured in each of the openings.

[0023] In some implementations, the waveguide section has a thickness of 1,000 μm or less and a width of at least 1 cm 2 and

[0024] The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features and advantages will be apparent from the description and drawings, and from the claims. The present specification also provides, for example, the following items: (Item 1) 1. A method of forming a waveguide section having a predetermined shape, the method comprising: Dispensing a photocurable material into a space between a first mold part and a second mold part opposite the first mold part; adjusting a relative separation between a surface of the first mold part relative to an opposing surface of the second mold part to fill the space between the first and second mold parts; irradiating the photocurable material in the space with radiation suitable to photocur the photocurable material to form a cured waveguide film such that different portions of the cured waveguide film have different stiffnesses; Separating the cured waveguide film from the first and second mold parts; and singulating the waveguide portions from the cured waveguide film; Including, The method, wherein the waveguide portion corresponds to a portion of the cured waveguide film having a higher stiffness than other portions of the cured waveguide film. (Item 2) 2. The method of claim 1, wherein different portions of the photocurable material are irradiated with different amounts of radiation. (Item 3) 3. The method of claim 2, wherein portions of the photocurable material irradiated with higher doses of radiation correspond to portions of the cured waveguide film having higher stiffness than portions of the waveguide film irradiated with lower doses of radiation. (Item 4) 3. The method of claim 2, wherein the different amounts of radiation are provided by irradiating the space through a mask. (Item 5) 5. The method of claim 4, wherein the mask includes an opening corresponding to a predetermined shape of the waveguide section. (Item 6) The waveguide section has a thickness of 1,000 μm or less and a width of at least 1 cm 2 and an area of (Item 7) 1. A method of forming a waveguide section having a predetermined shape, the method comprising: Dispensing a photocurable material into a space between a first mold part and a second mold part opposite the first mold part; adjusting a relative separation between a surface of the first mold part relative to an opposing surface of the second mold part to fill the space between the first and second mold parts; irradiating the photocurable material in the space with radiation suitable to photocure the photocurable material to form a cured waveguide film; separating the cured waveguide film from the first and second mold sections to provide the waveguide section; singulating a portion of the cured waveguide film in the predetermined shape from the cured waveguide film; annealing the singulated portion to provide the waveguide portion; Including, The method, wherein the waveguide section has a stiffness greater than a stiffness of the cured waveguide film. (Item 8) 8. The method of claim 7, wherein the singulated portions are annealed by irradiating the singulated portions with suitable radiation to photo-cure the photo-curable material. (Item 9) 8. The method of claim 7, wherein the singulated portion is annealed by heating the singulated portion. (Item 10) The waveguide section has a thickness of 1,000 μm or less and a width of at least 1 cm 2 and an area of (Item 11) 1. A method of forming a waveguide section having a predetermined shape, the method comprising: positioning a frame between a first mold part and a second mold part, the frame being rigid, the frame defining a first opening having the predetermined shape; dispensing a photocurable material into an opening in the frame; irradiating the photocurable material in the opening with radiation suitable to photocur the photocurable material to form a cured waveguide film having a stiffness different than a stiffness of the frame; Separating the cured waveguide film from the first and second mold parts; and singulating the waveguide portion from the hardened waveguide film by cutting a path along the frame, the path at least partially surrounding the opening, and extracting the waveguide portion including the hardened photocurable material from the frame along the path; A method comprising: (Item 12) Item 12. The method of item 11, wherein the frame defines a plurality of openings, each opening having the predetermined shape. (Item 13) Item 13. The method of item 12, wherein the light curable material is dispensed into each of the openings in the frame. (Item 14) Item 14. The method of item 13, wherein the photocurable material in each of the openings is simultaneously irradiated with the radiation. (Item 15) Item 15. The method of item 14, wherein the cured waveguide film includes the cured photocurable material in each of the openings. (Item 16) The waveguide section has a thickness of 1,000 μm or less and a width of at least 1 cm 2 Item 12. The method according to item 11, wherein the area of ​​the surface is 0.01 mm or less. [Brief description of the drawings]

[0025] [Figure 1] FIG. 1 is a schematic diagram of an exemplary system for producing a polymer.

[0026] [Diagram 2] FIG. 2 is a schematic diagram of an exemplary mold configuration with spacing features.

[0027] [Diagram 3]FIG. 3 is a schematic diagram of an exemplary process for producing a polymer product.

[0028] [Figure 4] FIG. 4 is a schematic diagram of another exemplary process for producing a polymeric product.

[0029] [Diagram 5] FIG. 5 is a schematic diagram of an exemplary singulation frame used to produce polymeric articles.

[0030] [Figure 6] FIG. 6 is a schematic diagram of an exemplary system for producing a polymer.

[0031] [Figure 7] FIG. 7 is a schematic diagram of a cross section of an exemplary optical film.

[0032] [Figure 8A] 8A-8C are flow chart diagrams of exemplary processes for producing polymeric products. [Figure 8B] 8A-8C are flow chart diagrams of exemplary processes for producing polymeric products. [Figure 8C] 8A-8C are flow chart diagrams of exemplary processes for producing polymeric products.

[0033] [Figure 9] FIG. 9 is a schematic diagram of an exemplary computer system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] Systems and techniques for producing polymer films are described herein. One or more of the described implementations can be used to produce polymer films in a highly precise, controlled, and reproducible manner. The resulting polymer films can be used in a variety of variable-sensitive applications, such as as part of an eyepiece in an optical imaging system.

[0035] In some implementations, polymer films can be produced such that wrinkles, uneven thickness, or other unintentional physical distortions are eliminated or otherwise reduced. This can be useful, for example, because the resulting polymer films exhibit more predictable physical and / or optical properties. For example, polymer films produced in this manner can diffract light in a more predictable and consistent manner and therefore may be more suitable for use with high-resolution optical imaging systems. In some cases, optical imaging systems using these polymer films can produce sharper and / or higher resolution images than may otherwise be possible with other polymer films.

[0036] An exemplary system 100 for producing polymer films is shown in Figure 1. The system 100 includes two actuatable stages 102a and 102b, two mold structures 104a and 104b, two light sources 106a and 106b, a support frame 108, and a control module 110.

[0037] During operation of the system 100, the two mold structures 104a and 104b (also referred to as "optical flats") are affixed (through clamps 112a and 112b) to the actuatable stages 102a and 102b, respectively. In some cases, the clamps 112a and 112b can be magnetic (e.g., electromagnets) and / or pneumatic clamps that allow the mold structures 104a and 104b to be reversibly mounted to and removed from the actuatable stages 102a and 102b. In some cases, the clamps 112a and 112b can be controlled by switches and / or by the control module 110 (e.g., by selectively applying electricity to the electromagnets of the clamps 112a and 112b and / or by selectively activating pneumatic mechanisms to engage or disengage the mold structures).

[0038] A photocurable material 114 (a photopolymer or light-activated resin that hardens when exposed to light) is deposited in mold structure 104b. Mold structures 104a and 104b are moved into proximity with one another (e.g., by moving actuable stages 102a and / or 102b vertically along support frame 108) such that photocurable material 114 is encapsulated by mold structures 104a and 104b. The photocurable material 114 is then hardened (e.g., by exposing photocurable material 114 to light from light sources 106a and / or 106b) to form a thin film having one or more features defined by mold structures 104a and 104b. After the photocurable material 114 is cured, the mold structures 104a and 104b are moved away from one another (e.g., by moving the actuable stages 102a and / or 102b vertically along the support frame 108) and the film is extracted.

[0039] The actuatable stages 102a and 102b are configured to support the mold structures 104a and 104b, respectively, and to manipulate the mold structures 104a and 104b, respectively, in one or more dimensions to control a gap volume 116 between the mold structures 104a and 104b.

[0040] For example, in some cases, the actuatable stage 102a can translate the mold structure 104a along one or more axes. As an example, the actuatable stage 102a can translate the mold structure 104a along an x-axis, a y-axis, and / or a z-axis in a Cartesian coordinate system (i.e., a coordinate system having three orthogonally arranged axes). In some cases, the actuatable stage 102a can rotate or tilt the mold structure 104a about one or more axes. As an example, the actuatable stage 102a can rotate the mold structure 104a along an x-axis (e.g., to "roll" the mold structure 104a), a y-axis (e.g., to "pitch" the mold structure 104a), and / or a z-axis (e.g., to "yaw" the mold structure 104a) in a Cartesian coordinate system. Translations and / or rotations about one or more other axes are also possible, either in addition to or instead of those described above. Similarly, the actuatable stage 102b can also translate the mold structure 104b along one or more axes and / or rotate the mold structure 104b about one or more axes.

[0041] In some cases, the actuatable stage 102a can manipulate the mold structure 104a according to one or more degrees of freedom (e.g., 1, 2, 3, 4, or more degrees of freedom). For example, the actuatable stage 102a can manipulate the mold structure 104a according to six degrees of freedom (e.g., translation along the x-, y-, and z-axes, and rotation about the x-, y-, and z-axes). Manipulation with one or more other degrees of freedom is also possible, either in addition to or instead of those described above. Similarly, the actuatable stage 102b can also manipulate the mold structure 104b according to one or more degrees of freedom.

[0042] In some cases, the actuatable stages 102a and 102b can include one or more motor assemblies configured to manipulate the mold structures 104a and 104b and control the gap volume 116. For example, the actuatable stages 102a and 102b can include a motor assembly 118 configured to manipulate the actuatable stages 102a and 102b, thereby repositioning and / or reorienting the actuatable stages 102a and 102b.

[0043] 1, both actuatable stages 102a and 102b can be moved relative to the support frame 108 to control the gap volume 116. However, in some cases, one of the actuatable stages can be moved relative to the support frame 108 while the other can remain stationary relative to the support frame 108. For example, in some cases, actuatable stage 102a can be configured to translate in one or more dimensions relative to the support frame 108 through a motor assembly 118, while actuatable stage 102b can be held static relative to the support frame 108.

[0044] Mold structures 104a and 104b collectively define an enclosure for photocurable material 114. For example, mold structures 104a and 104b, when aligned together, can define a hollow mold region (e.g., void volume 116) within which photocurable material 114 can be deposited and cured into a film. Mold structures 104a and 104b can also define one or more structures in the resulting film. For example, mold structures 104a and 104b can include one or more protruding structures (e.g., gratings) from surfaces 120a and / or 120b that impart corresponding channels in the resulting film. As another example, mold structures 104a and 104b can include one or more channels defined in surfaces 120a and / or 120b that impart corresponding protruding structures in the resulting film. In some cases, the mold structures 104a and 104b can impart a particular pattern to one or both sides of the resulting film. In some cases, the mold structures 104a and 104b need not impart any pattern of protrusions and / or channels on the resulting film at all. In some cases, the mold structures 104a and 104b can define particular shapes and patterns such that the resulting film is suitable for use as an eyepiece in an optical imaging system (e.g., such that the film has one or more light diffractive microstructures or nanostructures that impart particular optical properties to the film).

[0045] In some cases, the surfaces of the mold structures 104a and 104b facing each other may each be substantially flat such that the gap volume 116 defined therebetween exhibits a TTV of 500 nm or less. For example, the mold structure 104a may include a substantially flat surface 120a, and the mold structure 104b may have a substantially flat surface 120b. The substantially flat surface may be, for example, a surface that deviates from the flatness of an ideal flat surface (e.g., a completely flat surface) by 100 nm or less (e.g., 100 nm or less, 75 nm or less, 50 nm or less, etc.). The substantially flat surface may also have a local roughness of 2 nm or less (e.g., 2 nm or less, 1.5 nm or less, 1 nm or less, etc.) and / or an edge-to-edge flatness of 500 nm or less (e.g., 500 nm or less, 400 nm or less, 300 nm or less, 50 nm or less, etc.). In some cases, one or both of the surfaces of the mold structures 104 and 104b can be polished (e.g., to further increase the flatness of the surfaces). A substantially flat surface can be beneficial, for example, because it allows the mold structures 104a and 104b to define a void volume 116 that is substantially consistent in thickness (e.g., has a TTV of 500 nm or less) along the extent of the mold structures 104a and 104b. Thus, the resulting optical film can be flat (e.g., has a total thickness variation [TTV] and / or local thickness variation [LTV] less than or equal to a certain threshold, e.g., less than 500 nm, less than 400 nm, less than 300 nm, etc.). Additionally, the polished mold structures 104a and 104b can be beneficial, for example, in providing a smoother optical film for optical imaging applications. As an example, an eyepiece constructed from a smoother optical film can exhibit improved image contrast.

[0046] The TTV and LTV of an exemplary optical film 700 are shown in Figure 7. The TTV of the optical film 700 is the minimum thickness of the optical film 700 relative to the overall thickness of the optical film 700 (T min) is subtracted from the maximum thickness (T max ) (for example, TTV=T max -T min The LTV of the optical film 700 is the minimum thickness of the optical film 700 for a localized portion of the optical film 700 (T local min ) minus the maximum thickness (T local max ) (For example, LTV=T local max -T local min ). The size of the localized portion may vary depending on the application. For example, in some cases, the localized portion may be defined as a portion of the optical film having a particular surface area. For example, for an optical film intended for use as an eyepiece in an optical imaging system, the surface area of ​​the localized portion may be an area having a diameter of 2.5 inches. In some cases, the surface area of ​​the localized portion may vary depending on the eyepiece design. In some cases, the surface area of ​​the localized portion may vary depending on the dimensions and / or characteristics of the optical film.

[0047] Mold structures 104a and 104b are also rigid so as not to flex or bend during the film production process. The rigidity of mold structures 104a and 104b can be expressed in terms of their bending stiffness, which is a function of the mold structure's modulus of elasticity (E) and the second moment of the mold structure's area (I). In one case, the mold structures each have a bending stiffness of 1.5 Nm 2 The bending stiffness can be equal to or greater than the above.

[0048] Further still, mold structures 104a and 104b can be partially or completely transparent to radiation at one or more wavelengths suitable for photocuring the photocurable material (e.g., 315 nm to 430 nm). Further still, mold structures 104a and 104b can be made from a material that is thermally stable (e.g., does not change in size or shape) up to a certain threshold temperature (e.g., up to at least 200° C.). For example, mold structures 104a and 104b can be made from glass, silicon, quartz, Teflon, and / or polydimethylsiloxane (PDMS), among other materials.

[0049] In some cases, mold structures 104a and 104b can have a thickness above a certain threshold (e.g., thicker than 1 mm, thicker than 2 mm, etc.). This can be beneficial, for example, because a sufficiently thick mold structure is more difficult to bend. Thus, the resulting film is less likely to exhibit thickness irregularities. In some cases, the thickness of mold structures 104a and 104b can be within a certain range. For example, mold structures 104a and 104b can each be 1 mm to 50 mm thick. The upper end of the range can correspond, for example, to the limitations of an etching tool used to pattern mold structures 104a and 104b. In practice, other ranges are also possible depending on the implementation.

[0050] Similarly, in some cases, mold structures 104a and 104b can have diameters above a certain threshold (e.g., above 3 inches). This can be beneficial, for example, to allow relatively larger films and / or multiple individual films to be produced simultaneously. Furthermore, if unintentional particulate matter becomes trapped between the mold structures (e.g., between spacer structure 124 and the opposing mold structure 104a or 104b, such as at location 126), its effect on the flatness of the resulting film is reduced.

[0051] For example, with respect to mold structures 104a and 104b having a relatively small diameter, misalignment on one side of the mold structures 104a and 104b (e.g., due to trapped particulate matter on one of the spacer structures 124, such as at location 126) may result in a relatively more abrupt change in thickness within the gap volume 116 along the extent of the mold structures 104a and 104b. Thus, the resultant film or films will exhibit a more abrupt change in thickness (e.g., a steeper gradient in thickness along the length of the film).

[0052] However, for mold structures 104a and 104b having a relatively larger diameter, misalignment on one side of the mold structures 104a and 104b will result in a more gradual change in thickness within the gap volume 116 along the extent of the mold structures 104a and 104b. Thus, the resulting film or films will exhibit a less abrupt change in thickness (e.g., a relatively more gradual gradient in thickness along the length of the film). Thus, mold structures 104a and 104b having a sufficiently large diameter are more "tolerant" of trapped particulate matter and therefore can be used to produce more consistent and / or flatter films.

[0053] As an example, if a particle of 5 μm or less is confined along a point at the periphery of mold structures 104a and 104b (e.g., at location 126), and mold structures 104a and 104b each have a diameter of 8 inches, a gap volume having a horizontal surface area of ​​2 square inches within the confines of mold structures 104a and 104b will still have a TTV of 500 nm or less. Thus, when a photocurable material is deposited within the gap volume, the resulting film will similarly exhibit a TTV of 500 nm or less.

[0054] The light sources 106a and 106b are configured to generate radiation at one or more wavelengths suitable for photocuring the photocurable material 114. The one or more wavelengths may vary depending on the type of photocurable material used. For example, in some cases, a photocurable material (e.g., a UV-curable liquid silicone elastomer such as poly(methyl methacrylate) or poly(dimethyl siloxane)) may be used, and the light sources may be correspondingly configured to generate radiation having a wavelength in the range of 315 nm to 430 nm to photocure the photocurable material. In some cases, one or more of the mold structures 104a and 104b may be transparent or substantially transparent to radiation suitable for photocuring the photocurable material 114 such that radiation from the light sources 106a and / or 106b may pass through the mold structures 104a and / or 104b and impinge on the photocurable material 114.

[0055] The control module 110 is communicatively coupled to the actuatable stages 102a and 102b and is configured to control the gap volume 116. For example, the control module 110 can receive measurements regarding the gap volume 116 (e.g., the distance between the mold structures 104a and 104b at one or more locations) from a sensor assembly 122 (e.g., a device having one or more capacitive and / or pressure sensitive sensor elements) and, in response, reposition and / or reorient one or both of the mold structures 104a and 104b (e.g., by transmitting commands to the actuatable stages 102a and 102b).

[0056] 1, the system 100 can include one or more spacer structures 124 (e.g., protrusions or gaskets) that protrude from one or more surfaces of a mold structure (e.g., mold structure 104b) toward an opposing mold structure (e.g., mold structure 104a). The spacer structures 124 can each have a substantially equal vertical height such that when the mold structures 104a and 104b are brought together (e.g., pressed together), the spacer structures 124 abut the mold structures 104a and 104b and a substantially planar gap volume 116 is defined therebetween.

[0057] Additionally, the spacer structure 124 can be positioned proximate to and at least partially encapsulating the area of ​​the mold structures 104a and 104b for receiving and curing the photocurable material 114. This can be beneficial, for example, because it allows the system 100 to produce polymer films having low TTV and / or LTV without necessarily requiring that low TTV and / or LTV be maintained across the entire extent of the mold structures 104a and 104b. For example, multiple different polymer films can be produced without having to achieve low TTV across the entire volume between the mold structures 104a and 104b. Thus, the throughput of the production process can be increased.

[0058] For example, Figure 2 shows exemplary mold structures 104a and 104b with a spacer structure 124 disposed therebetween. When the mold structures 104a and 104b are joined together, the spacer structure 124 abuts the mold structures 104a and 104b, physically preventing the mold structures 104a and 104b from moving any closer to each other than the vertical height 202 of the spacer structure 124. Because the vertical heights 202 of each of the spacer structures 124 are substantially equal, a substantially flat gap volume 116 is defined between the mold structures 104a and 104b. In some cases, the vertical height 202 of the spacer structure 124 can be substantially equal to a desired thickness of the resulting film.

[0059] The spacer structures 124 can be constructed from a variety of materials. In some cases, the spacer structures 124 can be constructed from a material that is thermally stable (e.g., does not change in size or shape) up to a certain threshold temperature (e.g., up to at least 200° C.). For example, the spacer structures 124 can be made from glass, silicon, quartz, and / or Teflon, among other materials. In some cases, the spacer structures 124 can be constructed from the same material as the mold structures 104a and / or 104b. In some cases, the spacer structures 124 can be constructed from a different material than the mold structures 104a and / or 104b. In some cases, one or more of the spacer structures 124 can be integrally formed with the mold structures 104a and / or 104b (e.g., etched from the mold structures 104a and / or 104b, imprinted onto the mold structures 104a and / or 104b through a lithographic manufacturing process, or additively formed onto the mold structures 104a and / or 104b through an additive manufacturing process, etc.). In some cases, one or more of the spacer structures 124 can be separate from the mold structures 104a and / or 104b and can be fixed or affixed to the mold structures 104a and / or 104b (e.g., using a glue or other adhesive).

[0060] Although two spacer structures 124 are shown in Figure 2, this is merely an illustrative example. In practice, there can be any number of spacer structures 124 (e.g., one, two, three, four, or more) protruding from mold structure 104a, mold structure 104b, or both. Further still, although Figure 2 shows spacer structures 124 positioned along the perimeter of mold structures 104a and 104b, in practice, each spacer structure 124 can be positioned anywhere along the extent of mold structures 104a and 104b.

[0061] Additionally, in some implementations, other mechanisms can be used to define a gap volume between the mold structures 104a and 104b, either in addition to or instead of the spacer structures 124. For example, the motor assembly 118 can be configured to manipulate the actuatable stages 102a and 102b such that the mold structures 104a and 104b are separated from one another by a particular distance (e.g., in the z-direction or up-down direction in FIG. 1). In some implementations, the motor assembly 118 can include a locking mechanism 128 that prevents the motor assembly 118 from further moving the actuatable stages 102a and 102b once they are in a particular position relative to one another. The locking mechanism 128 can be selectively engaged and disengaged during the manufacturing process.

[0062] As described herein, a polymer film can be produced by encapsulating a photocurable material (e.g., a photopolymer or a light-activated resin that hardens when exposed to light) between two molds and curing the material (e.g., by exposing the material to light and / or heat). Additionally, a "singulation" process can be performed to separate the polymer film into multiple different products (e.g., by cutting the polymer film one or more times to obtain separate products having a specific size and shape) and / or to remove excess polymer material from the edges of the polymer products.

[0063] In some cases, performing a singulation process may introduce undesirable variations in the polymer film, making the resulting product less suitable for use in a variation-sensitive environment. For example, singulation is sometimes performed using techniques such as die-cutting, milling, water-jet cutting, ultrasonic cutting, or laser cutting to separate the polymer film into different parts. However, if the polymer film is too brittle, it may crack or chip when cut, resulting in poor edge quality. These imperfections may adversely affect the production process (e.g., because it is more difficult to make accurate and precise cuts during production) and reduce yields in applications that require high-precision edges. Furthermore, these imperfections may make the resulting polymer products less suitable for their intended use. For example, the chips or cracks may interfere with the intended optical properties of the polymer product, adversely affecting the performance of the polymer product. As another example, this may generate debris that may damage the polymer product and / or make it difficult to stack the polymer products together with a high degree of precision (e.g., in a multi-optical device). Furthermore, these imperfections can increase the variability of the polymer product from production to production, and therefore may make the polymer product less suitable for use in applications that are sensitive to variability.

[0064] Exemplary techniques for singulating polymer films are described herein. One or more of the described techniques can be implemented to separate the polymer film into multiple different products while eliminating or otherwise reducing the occurrence of unintentional chips or cracks. Thus, polymer products can be produced more efficiently, consistently, and accurately.

[0065] In some cases, singulation can be performed by cutting one or more portions of the polymer film that are not fully cured. Because these portions are less rigid and brittle compared to a fully cured polymer film, the cutting is less likely to cause cracks or chips. The curing of the polymer film can be controlled, for example, by adjusting the intensity of the light applied to the photocurable material during the curing process and / or the exposure time of the light.

[0066] In some cases, localized portions of the polymer film (e.g., "singulation zones") can be selectively hardened to a lesser extent than other portions of the polymer film. During the singulation process, the polymer film can be cut along these singulation zones. Because the singulation zones are less rigid and brittle, the cuts are less likely to result in cracks or chips, thereby improving the quality of the resulting polymer product.

[0067] As an example, Figure 3 is a simplified schematic diagram of an exemplary process for producing a polymer product using system 100. The process shown in Figure 3 can be used, for example, to produce optical components such as waveguides or eyepieces for use in a wearable imaging headset. For ease of illustration, portions of system 100 have been omitted.

[0068] In some cases, the process may be particularly useful for producing a waveguide or eyepiece suitable for use in a headset. For example, the process may be used to produce a waveguide or eyepiece having a thickness and / or cross-sectional area that is sufficient to guide light and project light that covers the field of vision of a headset wearer. As an example, the process may be used to produce a polymer film suitable for use in optical applications (e.g., as part of a waveguide or eyepiece in an optical imaging system). In some cases, the process may be particularly useful for producing a waveguide or eyepiece suitable for use in a headset. For example, the process may be used to produce a waveguide or eyepiece having a thickness and / or cross-sectional area that is sufficient to guide light and project light that covers the field of vision of a headset wearer. By way of example, the process can be used to achieve thicknesses of 1,000 μm or less (e.g., as measured along the z-axis of a Cartesian coordinate system), such as 800 μm or less, 600 μm or less, 400 μm or less, 200 μm or less, 100 μm or less, or 50 μm or less, and thicknesses of up to about 100 cm 2 Or less than or up to about 1,000 cm 2 Or less than 5cm 2 More than 10cm 2 More than 50cm 2 At least 1 cm, etc. (e.g., as measured relative to the xy plane of a Cartesian coordinate system) 2 and having a predetermined shape. In some cases, the polymer film can have a dimension of at least 1 cm (e.g., 2 cm or more, 5 cm or more, 8 cm or more, 10 cm or more, such as about 30 cm or less) in at least one direction in the xy plane.

[0069] 3, mold structure 104b includes surface 120b. Mold structure 104b is configured to define one or more encapsulated regions for casting and curing photocurable material 114 when mold structure 104b is mated with corresponding mold structure 104a. Furthermore, surface 120b defines several areas 300a-d, each of which corresponds to a size and shape of a different polymer product 302a-d (e.g., a waveguide or eyepiece).

[0070] Additionally, as described above, the mold structures 104a and 104b can also define one or more structures in the resulting film. For example, the mold structures 104a and 104b can include one or more protruding structures from the surfaces 120a and / or 120b of the mold structures that impart corresponding channels in the resulting film. As another example, the mold structures 104a and 104b can include one or more channels defined in the surfaces 120a and / or 120b that impart corresponding protruding structures in the resulting film. In some cases, the mold structures 104a and 104b can define a particular pattern such that the resulting film is suitable for use as a waveguide or eyepiece in an optical imaging system (e.g., such that the film has one or more light diffractive microstructures or nanostructures that impart particular optical properties to the film).

[0071] During the casting process, a quantity of photocurable material 114 is dispensed onto mold structure 104b. Mold structures 104a and 104b are then moved into proximity with one another (e.g., by moving actuable stages 102a and / or 102b described with respect to FIG. 1) such that photocurable material 114 is enclosed by mold structures 104a and 104b (e.g., as shown in the center portion of FIG. 3).

[0072] Additionally, the system includes a mask 304 positioned between the mold structure 104b and a light source (e.g., light source 106a shown and described with respect to FIG. 1). In some cases, the mask 304 can be positioned above the mold structure 104a (e.g., between the mold structure 104a and the light source). The mask 304 is configured to attenuate light emitted from the light source differently for different locations of the mold structures 104a and 104b, such that some portions of the photocurable material 114 are exposed to stronger light from the light source than other portions of the photocurable material 114. For example, the mask 304 can define several window areas 306a-d that transmit light having a first intensity onto the photocurable material 114 positioned on areas 300a-d of the mold structure 104b. Additionally, mask 304 may include one or more attenuating areas 308 that transmit light having a second, lower intensity onto photocurable material 114 positioned on areas of mold structure 104b beyond areas 300a-d. Thus, photocurable material 114 positioned on areas 300a-d is cured more quickly than photocurable material 114 positioned beyond areas 300a-d.

[0073] In some cases, the mask 304 can be a fused quartz mold or a thin wafer. The window areas 306a-d can be areas that are transparent or substantially transparent to wavelengths of light suitable for photocuring the photocurable material. In some cases, the window areas 306a-d can have a size and / or shape similar to the areas 300a-d. The one or more attenuation areas 308 can be one or more areas that include structures or other features (e.g., light diffusing structures or gratings) for attenuating the intensity of light for those same wavelengths of light. In some cases, the attenuation areas 308 can attenuate the intensity of light by at least 10% (e.g., 10%, 20%, 30%, or more).

[0074] The photocurable material 114 is then cured (e.g., by irradiating the photocurable material 114 with appropriate light 304 to photocure the photocurable material 114) to form a polymer film 310 having one or more features defined by the mold structures 104a and 104b.

[0075] As shown in the right portion of Figure 3, after the photocurable material 114 is cured, the polymer film 310 is extracted or "demolded" from the mold structures 104a and 104b (e.g., by moving the mold structures 104a and 104b away from each other and removing the polymer film 310 therebetween).

[0076] Due to the local attenuation of light by the mask 304, some portions of the polymer film 310 are more hardened than other portions of the polymer film 310. For example, portions 312a-d (e.g., corresponding to the size and shape of the polymer articles 302a-d) are hardened to a greater extent due to the transmission of light through the window areas 306a-d of the mask 304. However, portion 314 is hardened to a lesser extent due to the attenuated transmission of light through the attenuating area 308 of the mask 304. Thus, portions 312a-d are relatively more rigid and brittle compared to portion 314. In some cases, portions 312a-d can have a Young's modulus greater than 2.0 GPa, and portion 314 can have a Young's modulus between 1 GPa and 1.5 GPa.

[0077] The polymer film 310 can be singulated by cutting along portions 308 to separate the polymer film 310 into different polymer products 302a-d. As the cut is performed in a portion of the polymer film 310 that is less rigid and brittle (e.g., along a "singulation zone"), the cut results in fewer cracks or chips. Thus, the quality of the polymer products 302a-d is improved (e.g., compared to polymer products formed from singulating a fully cured polymer film). Furthermore, the polymer film may be cut more precisely, accurately, and consistently, resulting in products that exhibit lower product-to-product variability.

[0078] In some cases, the light source can be configured to emit light according to a specific spatial distribution to facilitate location-specific curing of the light-curable material. For example, the light source can be configured to emit a higher intensity of light along areas of the mold structures 104a and 104b corresponding to the products 302a-d (e.g., areas 300a-d) while emitting less intense light along other portions of the mold structures 104a and 104b (e.g., areas greater than 300a-d). In some cases, the light source can emit highly directional and / or collimated light to precisely tailor the exposure of light to specific portions of the mold structures 104a and 104b.

[0079] In practice, the operating parameters of the process may vary depending on the implementation. As an example, a photocurable material LPB-1102 (Mitsubishi) can be cured by exposing it to ultraviolet (UV) light. The mask 304 is configured such that the "singulation zone" of the polymer film (e.g., the area of ​​the polymer film that will be cut during the singulation process) is cured at approximately 15-75 mW / cm. 2The intensity of light for certain locations of the mold structure can be selectively attenuated so that the polymer film is exposed to light having an intensity of about 15-75 mW / cm 2 . As a result, the singulation zones of the polymer film have a tensile modulus in the range of about 0.5-1.5 GPa. These portions are soft enough that they can be easily singulated using die-cutting, water jet, and / or milling techniques without cracking or chipping. Additionally, the mask 304 selectively attenuates the intensity of light for certain locations of the mold structure (e.g., portions of the polymer film corresponding to the polymer article on the polymer article) so that those portions are fully cured. 2 In some cases, the exposure time can be in the range of 10 to 300 seconds, depending on the intensity of the light.

[0080] As another example, the thiolene-based photocurable material MLP-02 (Magic Leap) can also be cured by exposing it to UV light. The mask 304 is configured such that the singulation zone of the polymer film is approximately 15-150 mW / cm 2 The intensity of light for certain locations of the mold structure can be selectively attenuated so that the polymer film is exposed to light having an intensity of about 0.5-1.5 GPa. As a result, the singulation zones of the polymer film have a tensile modulus in the range of about 0.5-1.5 GPa. These portions are soft enough that they can be easily singulated using die-cutting, water jet, and / or milling techniques without cracking or chipping. Additionally, the mask 304 selectively attenuates the intensity of light for certain locations of the mold structure (e.g., portions of the polymer film corresponding to the polymer article on the polymer article) so that those portions are fully cured. 2 In some cases, the exposure time can be in the range of 60 to 420 seconds, depending on the intensity of the light.

[0081] In some cases, the photocurable material can be partially cured into a polymer film (e.g., a polymer film that is less rigid and brittle than a fully cured polymer film). During the singulation process, the partially cured polymer film can be cut into one or more polymer articles. Each of the polymer articles can then be annealed to complete the curing process. Thus, while singulation is performed, the polymer film is less rigid or brittle, which can improve the quality of the resulting polymer articles (e.g., by reducing cracks or chips along their edges).

[0082] As an example, FIG. 4 is a simplified schematic diagram of another exemplary process for producing a polymer product using the system 100. The process shown in FIG. 4 can be used to produce optical components such as a waveguide or eyepiece for use in a wearable imaging headset. For ease of illustration, parts of the system 100 have been omitted. In a similar manner as described with respect to FIG. 3, the process can be particularly useful for producing a waveguide or eyepiece suitable for use in a headset. For example, the process can be used to produce a waveguide or eyepiece having a thickness and / or cross-sectional area that is sufficient to guide light and project light that covers the field of view of a headset wearer.

[0083] 4, mold structure 104b includes surface 120b. Mold structure 104b is configured to define one or more encapsulated regions for casting and curing photocurable material 114 when mold structure 104b is mated with corresponding mold structure 104a. Additionally, surface 120b defines several areas 400a-d that respectively correspond to the sizes and shapes of different polymer products 402a-d (e.g., waveguides or eyepieces).

[0084] Additionally, as described above, the mold structures 104a and 104b can also define one or more structures in the resulting film. For example, the mold structures 104a and 104b can include one or more protruding structures from the surfaces 120a and / or 120b of the mold structures that impart corresponding channels in the resulting film. As another example, the mold structures 104a and 104b can include one or more channels defined in the surfaces 120a and / or 120b that impart corresponding protruding structures in the resulting film. In some cases, the mold structures 104a and 104b can define a particular pattern such that the resulting film is suitable for use as a waveguide or eyepiece in an optical imaging system (e.g., such that the film has one or more light diffractive microstructures or nanostructures that impart particular optical properties to the film).

[0085] During the casting process, a quantity of photocurable material 114 is dispensed onto mold structure 104b. Mold structures 104a and 104b are then moved into proximity with one another (e.g., by moving actuable stages 102a and / or 102b described with respect to FIG. 1 ) such that photocurable material 114 is enclosed by mold structures 104a and 104b (e.g., as shown in the center portion of FIG. 4 ).

[0086] The photocurable material 114 is then partially cured (e.g., by irradiating the photocurable material 114 with an appropriate light 304 to photocure the photocurable material 114) to form a partially cured polymer film 410 having one or more features defined by the mold structures 104a and 104b. In some cases, the photocurable material 114 can be partially cured by exposing it to an amount of light sufficient to harden the polymer film 410 until it has a stiffness and / or rigidity less than that of the finished polymer product 402a-d. Additionally, the photocurable material 114 can be cured to exhibit a degree of solidity (e.g., to retain its shape even when the mold structure 104a is "peeled" from the photocurable material 114). In some cases, the photocurable material 114 can be cured to have a Young's modulus of 1 GPa to 1.5 GPa.

[0087] 4, after the photocurable material 114 is partially cured, the polymer film 410 is extracted or "released" by "peeling" the mold structure 104a from the polymer film 410 (e.g., by moving the mold structures 104a and 104b away from each other). The polymer film 410 remains on the mold structure 104b.

[0088] The partially cured polymer film 410 can be singulated by cutting the polymer film 410 into different polymer products 402a-d. The partially cured polymer film 410 can be singulated while still positioned on the mold structure 104b. This can be beneficial, for example, because the flat surface of the mold structure 104b can reduce curvature or warping of the polymer film 410 during the singulation process. Furthermore, as the cutting is performed on the partially cured polymer film 410, which is less rigid and brittle (e.g., compared to a fully cured polymer film), the cutting results in fewer cracks or chips. Thus, the quality of the polymer products 402a-d is improved (e.g., compared to a polymer product formed from singulating a fully cured polymer film). Furthermore, the polymer film can be cut more precisely, accurately, and consistently, resulting in products that exhibit lower product-to-product variability.

[0089] After the singulation process, the polymer products 402a-d are annealed to complete the curing process. As an example, the polymer products 402a-d can be heated and / or exposed to additional light until fully cured (e.g., until they exhibit a certain degree of stiffness and / or rigidity greater than that of a partially cured polymer film). In some cases, the polymer products 402a-d can be annealed until they have a Young's modulus greater than 2.0 GPa. The polymer products 402a-d can be annealed while still positioned on the mold structure 104b. After annealing, the polymer products 402a-d can be extracted from the mold structure 104b (e.g., by "peeling" the polymer products 402a-d from the mold structure 104b).

[0090] In practice, the operating parameters of the process may vary depending on the implementation. As an example, the photocurable material LPB-1102 (Mitsubishi) operates at approximately 15-75 mW / cm 2The polymeric product can be partially cured by exposing it to UV light having an intensity of 10 ...

[0091] As another example, the thiol-based photocurable material MLP-02 (Magic Leap) has a light output of about 15 to 150 mW / cm 2 The polymeric product can be partially cured by exposing it to UV light having an intensity of 1000 nm to 1000 nm. The exposure time can be in the range of 60-420 seconds, depending on the intensity of the light. This results in a partially cured polymeric film having a tensile modulus in the range of about 0.5-1.5 GPa. It is soft enough that it can be easily singulated without cracking or chipping using die-cutting, water jet, and / or milling techniques. After singulation, each polymeric product can be annealed by exposing it to a heating cycle of 125°C to 250°C for 20-120 minutes. In some cases, the polymeric product may shrink in size after the heating cycle (e.g., shrink in thickness by 5-10 nm, depending on the initial degree of cross-linking within the photocurable material before it is annealed).

[0092] In some cases, the photocurable material can be deposited into a singulation frame. The singulation frame can be constructed from one or more materials that are rigid but not brittle so that it can be cut without introducing cracks or chips along its edges. The photocurable material can be cured directly within the singulation frame and singulated into separate polymeric products by cutting along the singulation frame but not along the photocurable material itself. Thus, the quality of the resulting polymeric product is improved (e.g., because the polymeric material is not cut directly at all).

[0093] A plan view of an exemplary singulation frame 500 is shown in Figure 5. The singulation frame 500 defines a number of openings 502a-d, each corresponding to a different polymer product. Additionally, the singulation frame 500 defines a network of channels 504 that interconnect the openings 502a-d.

[0094] The singulation frame 500 is constructed from one or more materials that are rigid but not brittle so that it may be cut without introducing cracks or chips along its edges. In some cases, the singulation frame 500 may be constructed from one or more polymers, such as polycarbonate-, acrylate-, and / or polystyrene-based materials, that are transparent or partially transparent to wavelengths of light (e.g., UV wavelengths) suitable for curing the photocurable material. In some cases, the singulation frame 500 may include a polymer, such as Teflon, along the edges that define the openings 502a-d.

[0095] The thickness of the singulation frame 500 can vary depending on the implementation. In some cases, the singulation frame 500 can have a thickness that is at least 50 μm less than the height of the spacer structures 126 (e.g., 50 μm less than the height of the spacer structures, 100 μm less than the height of the spacer structures, 150 μm less than the height of the spacer structures, etc.) such that the singulation frame 500 does not interfere with the interaction between the spacer structures 126 and the mold structures 104a and 104b.

[0096] During the production process, the singulation frame 500 is positioned over the mold structure 104b (e.g., such that the openings 502a-d align with corresponding portions of the mold structure 104b to define features of the polymer product). Photocurable material is dispensed into the openings 502a-d. The mold structures 104a and 104b are moved into proximity with one another (e.g., by moving the actuable stages 102a and / or 102b described with respect to FIG. 1 ) such that the photocurable material is encapsulated by the mold structures 104a and 104b within the singulation frame 500. The photocurable material is cured by application of heat and / or light.

[0097] After curing, a singulation process is performed by cutting the singulation frame 500 along the periphery of the openings 502a-d (e.g., along paths 506a-d that at least partially surround the openings 502a-d). Thus, each polymer product includes hardened polymer material that is surrounded or "framed" by a portion of the singulation frame 500.

[0098] Although exemplary mold structure 104a and singulation frame are shown and described above, these are merely illustrative examples. In practice, the respective configurations may vary depending on the implementation. As an example, the mold structure may include areas for casting and curing any number of different polymer products (e.g., one, two, three, four, five, or more), each having any size or shape. As another example, the singulation frame may include any number of openings to accommodate casting and curing any number of different polymer products (e.g., one, two, three, four, five, or more), each having any size or shape.

[0099] In some cases, the system 100 also includes one or more heating elements for applying heat to the photocurable material during the curing process. This can be beneficial, for example, to expedite the curing process. For example, in some cases, both heat and light can be used to cure the photocurable material. For example, the application of heat can be used to accelerate the curing process, make the curing process more efficient, and / or make the curing process more consistent. In some cases, the curing process can be carried out using heat instead of light. For example, the application of heat can be used to cure the photocurable material and a light source does not need to be used.

[0100] An exemplary system 600 for producing a polymer film is shown in Figure 6. In general, system 600 may be similar to system 100 shown in Figure 1. For example, system 600 may include two actuatable stages 102a and 102b, two mold structures 104a and 104b, a support frame 108, and a control module 110. For ease of illustration, control module 110 is not shown in Figure 6.

[0101] However, in this embodiment, the system 600 does not include two light sources 106a and 106b. Instead, it includes two heating elements 602a and 602b positioned adjacent to the mold structures 104a and 104b, respectively. The heating elements 602a and 602b are configured to move with the mold structures 104a and 104b (e.g., through the actuable stages 102a and 102b) and are configured to apply heat to the photocurable material 114 between the mold structures 104a and 104b during the curing process.

[0102] The operation of the heating elements 602a and 602b can be controlled by the control module 110. For example, the control module 110 can be communicatively coupled to the heating elements 602a and 602b and can selectively apply heat to the light curable material 114 (e.g., by transmitting commands to the heating elements 602a and 602b).

[0103] Exemplary heating elements 602a and 602b are metallic heating elements (e.g., nichrome or resistive wire), ceramic heating elements (e.g., molybdenum disilicide or PTC ceramic elements), polymer PTC heating elements, composite heating elements, or combinations thereof. In some cases, heating elements 602a and 602b can include metal plates to promote uniform heat transfer to mold structures 104a and 104b.

[0104] 6, the system can include any number of heating elements (e.g., one, two, three, four, or more) or none at all. Additionally, the system 600 is shown without light sources 106a and 106b, but in some cases the system can include one or more light sources in conjunction with one or more heating elements.

[0105] FIG. 8A illustrates an exemplary process 800 for producing a polymer product. Process 800 can be implemented, for example, using system 100 or 600. In some cases, process 800 can be used to produce polymer films suitable for use in optical applications (e.g., as part of a waveguide or eyepiece in an optical imaging system). In some cases, the process can be particularly useful for producing a waveguide or eyepiece suitable for use in a headset. For example, the process can be used to produce a waveguide or eyepiece having a thickness and / or cross-sectional area that is sufficient to guide light and project light to cover the field of view of a headset wearer (e.g., as measured along the z-axis of a Cartesian coordinate system) of 1,000 μm or less, such as 800 μm or less, 600 μm or less, 400 μm or less, 200 μm or less, 100 μm or less, or 50 μm or less, and a thickness of up to about 100 cm. 2 Or less than or up to about 1,000 cm 2 Or less than 5cm 2 More than 10cm 2 More than 50cm 2 At least 1 cm, etc. (e.g., as measured relative to the xy plane of a Cartesian coordinate system) 2 and having a predetermined shape. In some cases, the polymer film can have a dimension of at least 1 cm (e.g., 2 cm or more, 5 cm or more, 8 cm or more, 10 cm or more, such as about 30 cm or less) in at least one direction in the xy plane.

[0106] In process 800, a photocurable material is dispensed into a space between a first mold part and a second mold part opposite the first mold part (step 802). Exemplary mold parts are shown and described, for example, with respect to Figures 1-3.

[0107] The relative separation between the surfaces of the first mold part is adjusted with respect to a surface of the second mold part opposite the surface of the first mold part to fill the space between the first and second mold parts (step 804). Exemplary techniques for adjusting the relative separation between the two mold parts are shown and described, for example, with respect to FIGS.

[0108] The photocurable material in the space is irradiated with appropriate radiation to photocure the photocurable material to form a cured waveguide film such that different portions of the cured waveguide film have different stiffnesses (step 806). In some cases, different portions of the photocurable material are irradiated with different amounts of radiation. The portions of the photocurable material irradiated with a higher amount of radiation can correspond to portions of the cured waveguide film that have a higher stiffness than the portions of the waveguide film irradiated with a lower amount of radiation. In some cases, the different amounts of radiation are provided by irradiating the space through a mask. The mask can include openings that correspond to the predetermined shapes of the waveguide portions. Exemplary techniques and masks for selectively controlling the stiffness of the waveguide film during photocuring are shown and described, for example, with respect to FIG. 3.

[0109] The cured waveguide film is separated from the first and second mold portions (step 808). Waveguide sections are then singulated from the cured waveguide film (step 810). The waveguide sections correspond to portions of the cured waveguide film that have a higher stiffness than other portions of the cured waveguide film. In some cases, the waveguide sections can be singulated using techniques such as die cutting, milling, water jet cutting, ultrasonic cutting, or laser cutting.

[0110] FIG. 8B illustrates another exemplary process 820 for producing a polymer product. Process 820 can be implemented, for example, using system 100 or 600. Similar to process 800, process 800 can be used to produce polymer films suitable for use in optical applications (e.g., as part of a waveguide or eyepiece in an optical imaging system), and can be particularly useful for producing a waveguide or eyepiece suitable for use in a headset. For example, the process can be used to produce a waveguide or eyepiece having a thickness and / or cross-sectional area that is sufficient to guide light and project light to cover the field of view of a headset wearer. As an example, the process can be used to produce a polymer film having a thickness of 1,000 μm or less (e.g., as measured along the z-axis of a Cartesian coordinate system) and a cross-sectional area of ​​at least 1 cm (e.g., as measured relative to the xy plane of a Cartesian coordinate system). 2 The polymeric film can be used to produce a polymeric article having a predetermined shape and an area of ​​at least 1 cm in at least one direction in the xy plane.

[0111] In process 820, a photocurable material is dispensed into a space between a first mold part and a second mold part opposite the first mold part (step 822). Exemplary mold parts are shown and described, for example, with respect to Figures 1-3.

[0112] The relative separation between the surfaces of the first mold part is adjusted with respect to a surface of the second mold part opposite the surface of the first mold part to fill the space between the first and second mold parts (step 824). Exemplary techniques for adjusting the relative separation between the two mold parts are shown and described, for example, with respect to FIGS.

[0113] The photocurable material in the space is irradiated with appropriate radiation to photocure the photocurable material to form a cured waveguide film (step 826). Exemplary techniques and systems for irradiating the photocurable material are shown and described, for example, with respect to FIG.

[0114] The cured waveguide film is separated from the first and second mold portions to provide a waveguide section (step 828). A portion of the cured waveguide film is then singulated from the cured waveguide film in a predetermined shape (830). In some cases, the portion of the waveguide section can be singulated using techniques such as die cutting, milling, water jet cutting, ultrasonic cutting, or laser cutting.

[0115] The singulated portions are annealed to provide waveguide portions (step 832). The waveguide portions have a stiffness greater than that of the cured waveguide film. In some implementations, the singulated portions are annealed by irradiating the singulated portions with suitable radiation to photo-cure the photo-curable material. In some implementations, the singulated portions are annealed by heating the singulated portions. An exemplary technique for annealing singulated portions of a waveguide film is shown and described, for example, with respect to FIG. 4.

[0116] FIG. 8C illustrates another exemplary process 840 for producing a polymer product. Process 840 can be implemented, for example, using system 100 or 600. Similar to processes 800 and 820, process 840 can be used to produce polymer films suitable for use in optical applications (e.g., as part of a waveguide or eyepiece in an optical imaging system), and can be particularly useful for producing a waveguide or eyepiece suitable for use in a headset. For example, the process can be used to produce a waveguide or eyepiece having a thickness and / or cross-sectional area that is sufficient to guide light and project light to cover the field of view of a headset wearer. As an example, the process can be used to produce a polymer film having a thickness of 100 μm or less (e.g., as measured along the z-axis of a Cartesian coordinate system) and a cross-sectional area of ​​at least 1 cm (e.g., as measured relative to the xy plane of a Cartesian coordinate system). 2 The polymeric film can be used to produce a polymeric article having a predetermined shape and an area of ​​at least 1 cm in at least one direction in the xy plane.

[0117] In process 840, a frame is positioned between the first and second mold parts (step 842). The frame has a particular rigidity. Additionally, the frame defines a first opening having a predetermined shape. In some cases, the frame defines a plurality of openings, each having a predetermined shape. Exemplary mold parts are shown and described, for example, with respect to FIGS. 1-3. Exemplary frames are shown and described, for example, with respect to FIG. 5.

[0118] A photocurable material is dispensed into the openings in the frame, step 844. In some cases, a photocurable material is dispensed into each of the openings in the frame.

[0119] The photocurable material in the apertures is irradiated with appropriate radiation to photocur it to form a cured waveguide film having a stiffness different from that of the frame (step 846). In some cases, the photocurable material in each of the apertures is irradiated with radiation simultaneously. Exemplary techniques and systems for irradiating the photocurable material are shown and described, for example, with respect to FIG.

[0120] The cured waveguide film is separated from the first and second mold portions (step 848). The waveguide portions are then singulated from the waveguide film by cutting paths along the frame and extracting the waveguide portions, including the cured photocurable material, from the frame along the paths (step 850). The paths at least partially surround the openings. In some cases, the cured waveguide film includes the cured photocurable material in each of the openings. In some cases, portions of the waveguide portions can be singulated using techniques such as die cutting, milling techniques, water jet cutting, ultrasonic cutting, or laser cutting.

[0121] Some implementations of the subject matter and operations described herein can be implemented in digital electronic circuitry, or in computer software, firmware, or hardware, including the structures disclosed herein and their structural equivalents, or in combinations of one or more of them. For example, in some implementations, the control module 110 can be implemented using digital electronic circuitry, or in computer software, firmware, or hardware, or in combinations of one or more of them. In another example, the process 800 shown in FIG. 8 can be implemented, at least in part, using digital electronic circuitry, or in computer software, firmware, or hardware, or in combinations of one or more of them.

[0122] Some implementations described herein can be implemented as one or more groups or modules of digital electronic circuitry, computer software, firmware, or hardware, or a combination of one or more of them. Although different modules can be used, each module need not be distinct, and multiple modules can be implemented on the same digital electronic circuitry, computer software, firmware, or hardware, or a combination of them.

[0123] Some implementations described herein can be implemented as one or more computer programs, i.e., one or more modules of computer program instructions, encoded on a computer storage medium for execution by or to control the operation of a data processing apparatus. The computer storage medium can be or be included in a computer readable storage device, a computer readable storage substrate, a random or serial access memory array or device, or a combination of one or more of them. Also, a computer storage medium is not a propagated signal, but a computer storage medium can be a source or destination of computer program instructions encoded in an artificially generated signal. A computer storage medium can also be or be included in one or more separate physical components or media (e.g., multiple CDs, disks, or other storage devices).

[0124] The term "data processing apparatus" encompasses all kinds of apparatus, devices, and machines for processing data, including, by way of example, a programmable processor, a computer, a system on a chip, or a plurality or combination of the foregoing. The apparatus may include special purpose logic circuits, such as a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC). In addition to hardware, the apparatus may also include code that creates an execution environment for the computer program, such as code that configures a processor firmware, a protocol stack, a database management system, an operating system, a cross-platform run-time environment, a virtual machine, or a combination of one or more of these. The apparatus and execution environment may implement a variety of different computing model infrastructures, such as web services, distributed computing, and grid computing infrastructures.

[0125] A computer program (also known as a program, software, software application, script, or code) can be written in any form of programming language, including compiled or interpreted languages, declarative or procedural languages. A computer program may, but need not, correspond to a file in a file system. A program can be stored in a portion of a file that holds other programs or data (e.g., one or more scripts stored in a markup language document), in a single file dedicated to the program, or in multiple cooperating files (e.g., files that store one or more modules, subprograms, or portions of code). A computer program can be deployed to be executed on one computer, or on multiple computers that are located at one site or distributed across multiple sites and interconnected by a communication network.

[0126] Some of the processes and logic flows described herein may be implemented by one or more programmable processors executing one or more computer programs to perform actions by operating on input data and generating output. The processes and logic flows may also be implemented by, and apparatus may also be implemented as, special purpose logic circuitry, such as an FPGA (field programmable gate array) or an ASIC (application specific integrated circuit).

[0127] Processors suitable for executing computer programs include, by way of example, both general-purpose and special-purpose microprocessors, and processors of any kind of digital computer. Generally, a processor will receive instructions and data from a read-only memory or a random-access memory or both. A computer includes a processor for performing actions according to the instructions, and one or more memory devices for storing instructions and data. A computer may also include one or more mass storage devices, such as magnetic, magneto-optical, or optical disks, for storing data, or be operatively coupled thereto to receive data therefrom or transfer data thereto, or both. However, a computer need not have such devices. Devices suitable for storing computer program instructions and data include all forms of non-volatile memory, media, and memory devices, including, by way of example, semiconductor memory devices (e.g., EPROM, EEPROM, flash memory devices, and others), magnetic disks (e.g., internal hard disks, removable disks, and others), magneto-optical disks, and CD-ROM and DVD-ROM disks. The processor and memory may be supplemented by, or incorporated in, special-purpose logic circuitry.

[0128] To provide for interaction with a user, the operations can be implemented on a computer having a display device (e.g., a monitor or another type of display device) for displaying information to the user, and a keyboard and pointing device (e.g., a mouse, trackball, tablet, touch-sensitive screen, or another type of pointing device) by which the user may provide input to the computer. Other types of devices can also be used to provide interaction with the user, for example, feedback provided to the user can be any form of sensory feedback, e.g., visual feedback, auditory feedback, or tactile feedback, and input from the user can be received in any form, including acoustic, speech, or tactile input. Additionally, the computer can interact with the user by sending documents to and receiving documents from a device used by the user, for example, by sending a web page to a web browser on the user's client device in response to a request received from the web browser.

[0129] A computer system may include a single computing device or multiple computers operating in close proximity or generally remote from each other and typically interacting through a communications network. Examples of communications networks include local area networks ("LANs") and wide area networks ("WANs"), internetworks (e.g., the Internet), networks with satellite links, and peer-to-peer networks (e.g., ad hoc peer-to-peer networks). The relationship of client and server may arise by virtue of computer programs running on separate computers and having a client-server relationship to each other.

[0130] 9 illustrates an exemplary computer system 900 including a processor 910, a memory 920, a storage device 930, and an input / output device 940. Each of the components 910, 920, 930, and 940 may be interconnected, for example, by a system bus 950. The processor 910 may process instructions for execution within the system 900. In some implementations, the processor 910 is a single-threaded processor, a multi-threaded processor, or another type of processor. The processor 910 may process instructions stored in the memory 920 or on the storage device 930. The memory 920 and the storage device 930 may store information within the system 900.

[0131] The input / output devices 940 provide input / output operations for the system 1600. In some implementations, the input / output devices 940 may include one or more of a network interface device, e.g., an Ethernet card, a serial communication device, e.g., an RS-232 port, and / or a wireless interface device, e.g., an 802.11 card, a 3G wireless modem, a 4G wireless modem, etc. In some implementations, the input / output devices may include a driver device configured to receive input data and send output data to other input / output devices, e.g., keyboards, printers, and display devices 960. In some implementations, mobile computing devices, mobile communication devices, and other devices may be used.

[0132] Although the present specification contains many details, these should not be construed as limitations on the scope of the claims, but rather as descriptions of features specific to particular examples. Certain features described in the present specification in the context of separate implementations can also be combined. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple embodiments separately or in any suitable subcombination.

[0133] Although several implementations have been described, it should be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, other implementations are within the scope of the following claims.

Claims

1. A method comprising: dispensing a photocurable material between a first mold part and a second mold part opposite the first mold part; masking the photocurable material to define different portions of the photocurable material; irradiating the masked photocurable material between the first mold part and the second mold part with suitable radiation to photocurable the photocurable material and form the cured waveguide film such that different portions of the cured waveguide film corresponding to the different portions of the photocurable material have different stiffnesses; A method comprising:

2. The method of claim 1, wherein the different portions of the photocurable material are irradiated with different amounts of radiation.

3. The method of claim 2, wherein a portion of the photocurable material that is irradiated with a greater amount of radiation corresponds to a portion of the hardened waveguide film that has a higher stiffness than a portion of the hardened waveguide film that corresponds to a portion of the photocurable material that is irradiated with a lesser amount of radiation.

4. The method of claim 2, wherein the masking causes different amounts of radiation to be delivered to the different portions of the photocurable material when irradiating the photocurable material between the first mold part and the second mold part.

5. The method of claim 4, wherein the mask includes an opening corresponding to the shape of the waveguide portion.

6. The method according to claim 5, wherein the waveguide portion has a thickness of 1,000 μm or less and an area of ​​1 cm 2 or more.

7. The method of claim 5, wherein one or more of the other portions of the hardened waveguide film encapsulate portions of the hardened waveguide film corresponding to the waveguide portions.

8. Separating the cured waveguide film from the first mold part and the second mold part; and singulating waveguide sections from the cured waveguide film; Further comprising: The method of claim 1 , wherein the waveguide portion corresponds to one or more portions of the cured waveguide film that have a higher stiffness than other portions of the cured waveguide film.

9. Further comprising singulating one or more additional waveguide sections from the cured waveguide film; The method of claim 8 , wherein the additional waveguide portion corresponds to a portion of the cured waveguide film that has a higher stiffness than a portion of the cured waveguide film that does not correspond to a waveguide portion.

10. The method of claim 1, wherein the masking includes placing a mask having at least one opening between the photocurable material and a source of radiation, each of the at least one opening defining a corresponding one of the portions of the photocurable material.

11. The method of claim 10, wherein the at least one opening causes the radiation passing through the mask to be attenuated less than other areas of the mask.

12. A method comprising: positioning a frame between a first mold part and a second mold part, said frame having a first rigidity, said frame defining at least one mold volume; dispensing a photocurable material into the at least one mold volume of the frame; irradiating the photocurable material in the at least one mold volume with radiation suitable to photocure the photocurable material to form a cured waveguide film having a second stiffness different from the first stiffness; A method comprising:

13. The method of claim 12, wherein the frame defines a plurality of mold volumes interconnected by a network of channels, each mold volume defining a different portion of the photocurable material.

14. The method of claim 13, wherein the photocurable material is dispensed into each of the plurality of mold volumes.

15. The method of claim 14, wherein the photocurable material in each of the plurality of mold volumes is simultaneously irradiated with the radiation.

16. The method of claim 15, wherein the hardened waveguide film comprises the hardened photocurable material in each of the plurality of mold volumes.

17. The method of claim 12, wherein the first stiffness is greater than the second stiffness.

18. The method of claim 17, further comprising: removing a waveguide portion from the cured waveguide film; cutting a path along the frame, the path at least partially enclosing the at least one mold volume; and extracting the waveguide portion including the hardened photocurable material from the frame along the path. The method of claim 12 including singulating.

19. The method of claim 18, wherein the waveguide portion has a thickness of 1,000 μm or less and an area of ​​1 cm 2 or more.

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