Curved fly's-eye lens based on DMD digital photoetching and preparation method of curved fly's-eye lens

A curved surface compound eye and lens technology, which is applied in the field of curved surface compound eye lens and its preparation, can solve the problems of small field of view, cumbersome process, and high cost, and achieve the effects of controllable arc bending, reduced manufacturing difficulty, and improved production efficiency

Pending Publication Date: 2022-04-15

XIHUA UNIV

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AI-Extracted Technical Summary

Problems solved by technology

[0005] During the fabrication of microlens arrays and spherical substrates, different methods can produce varying degrees of process defects and difficulties

For example, in the manufacture of microlens arrays, the method of directly manufacturing microlenses is high in cost and complicated in the preparation process

Manufacturing cost can be reduced by indirect manufacturing of the master and then inversion process. The same master can produce a large number of microlenses, but it is easy to contaminate and damage the master in the inversion process, and the process is cumbersome

Using physical means to change the curvature of the PDMS fil...

Method used

(1) choose silicon chip as substrate, prepare the mixed solution of hydrofluoric acid and hydrogen peroxide with the ratio of volume ratio 10:1, and place silicon chip in mixed solution and soak 2min, use flowing deionized water to rinse silicon subsequently Then place the silicon wafer in an oven and bake for 10 minutes, so as to completely evaporate excess water and ensure that the surface of the silicon wafer is dry.

(1) choose silicon chip as substrate, prepare the mixed solution of hydrofluoric acid and hydrogen peroxide with the ratio of volume ratio 10:1, and place silicon chip in mixed solution and soak 2min, use flowing deionized water to rinse silicon subsequently Then place the silicon wafer in an oven and bake for 5 minutes, so as to completely evaporate excess water and ensure that the surface of the silicon wafer is dry.

(1) choose silicon chip as substrate, prepare the mixed solution of hydrofluoric acid and hydrogen peroxide with the ratio of volume ratio 10:1.5, and place silicon chip in mixed solution and soak 1min, use flowing deionized water to rinse silicon subsequently Then place the silicon wafer in an oven and bake for 8 minutes, so as to completely evaporate excess water and ensure that the surface of the silicon wafer is dry.

(3) according to the lens array structural feature of design, calculate the gray scale coding information of its corresponding DMD microreflection mirror, information can be imported in DMD and can begin to expose photoresist, exposure time needs according to exposure dose and The light intensity of the micro-mirror is determined. In this embodiment, the exposure time is 50s. Then use a 1:1 mixture of developer and plasma water that matches the photoresist for development, and the positive photoresist will retain the unexposed area. Then heat reflow treatment is carried out to remove the burr glue layer that has not completely fallen off in the exposure and development process, thereby improving the surface smoothness of the processed structure. The temperature of heat reflow is 130°C, and the baking time is 2 minutes, and the negative mold of the microlens array is obtained. .

(3) according to the lens array structural feature of design, calculate the greyscale coding information of its corresponding DMD microreflection mirror, information can be imported in DMD and can begin to expose photoresist, and exposure time needs accord...

Abstract

The invention discloses a curved fly's-eye lens based on DMD digital lithography and a preparation method thereof.The curved fly's-eye lens is of a hemispherical structure, the hemispherical structure sequentially comprises a hemispherical curved focal plane, an elastic film and a curved micro-lens array from inside to outside, all levels of sub-eyes form the curved micro-lens array, and the curved micro-lens array comprises a spherical curved focal plane, an elastic film and a curved micro-lens array. All the levels of sub-eyes comprise a first-level sub-eye located in the center of the curved-surface micro-lens array and a plurality of circles of n-level sub-eyes arranged with the first-level sub-eye as the circle center, wherein n is an integer larger than or equal to 2. A plurality of photosensitive sensors in one-to-one correspondence with the sub-eyes are uniformly arranged on one surface, facing the elastic film, of the hemispherical curved focal plane. According to the invention, three-dimensional photoetching is carried out on the micro-lens structure through digital photoetching of the digital micro-mirror DMD, and the micro-lens array can be obtained only through one-time reverse molding. The aperture and rise of the sub-eye and the curvature radius of the curved fly-eye lens are controllable, the manufactured micro-lens is high in size and surface shape precision and good in surface uniformity, the manufacturing process is simple, and the cost is low.

Application Domain

Lens

Technology Topic

OphthalmologySurface shape +7

Image

Examples

Experimental program(3)

Example Embodiment

[0047] Example 1

[0048] This embodiment provides a method of preparing a surface diaphraglass based on DMD digital photolithography, including the following steps:

[0049] (1) Select the silicon wafer as the substrate, prepare the mixed solution of hydrofluoric acid with the hydrofluoride in the proportion of volume ratio 10: 1, and placed the silicon wafer to soak for 2 min, then the surface of the wafer is flushed with flow deionized water, The silicon wafer was placed in an oven for 5 min, thus thoroughly evaporating excess water to ensure drying the surface of the silicon wafer.

[0050] (2) The AZ9260 positive photoresist was at 400 rpm, lasting 30s, and finally coated on the silicon film having a thickness of about 20 μm. The follow-up of the photoresist was previously baked, and the process parameters of 120 ° C / 3 min were used, that is, the silicon wafer to homogenate was placed on the grilled plate of the constant temperature 120 ° C for 3 min. After the baking is over, the silicon wafer is required to stand in a clean environment for a few minutes to cool to the room temperature environment.

[0051] (3) According to the design of the design lens array structure, the gradation coding information corresponding to the DMD microdeter is calculated, and the information is introduced into the DMD to begin to expose the photoresist, and the exposure time needs to be based on the exposure dose and micro-mirror. Light intensity decides.

[0052] The proportional relationship is as follows, but is not limited to the formula.

[0053]

[0054] E (x, y) represents the final exposure dose, unit is mJ / cm 2 , I represents the number of binary bits, the minimum value is 0, the maximum value is 7, and the position for indicating the binary information read by the current DMD, V represents the binary value of the DMD reads in this position. p 0 Indicates the peak of the Gaussian curve, the symbol θ represents the Gauss radius.

[0055] The present embodiment is exposed to 50s. The 1: 1 mixture of the developing fluid and plasma water supporting the photoresist will be developed, and the positive photoresist will remain unexposed. Then, the heat reflow treatment is performed, and the exposure development is removed, thereby increasing the surface smoothness of the machining structure, the temperature of the heat reflow is 120 ° C, the baking time is 3 minutes, resulting in a negative mode of the microlens array .

[0056] (4) After mixing the liquid PDMS and the silicone resin solution at a ratio of 10: 1, the mixed liquid is placed in a vacuum drying cabinet, and the bubbles are dissipated, and the mixed liquid is slowly injected into the negative mold, and then Placed in an oven at 70 ° C, to be mixed with liquid, form a plane microlens array. All sub-eyes in the array have the same size. The center of the microlens array is primary, the second-grade binds are arranged in circular shaped eyes and are arranged around the primary sub-eye, and the three-stage children are also rounded at the same time as a one-stage eyed eye. The circle is arranged outside the eyes. With this type, the microlens array contains a total of nine-level eyes.

[0057] (5) Production of a surface hemispherical force film, a mixed solution is formed in a proportion of 10: 1 in a ratio of 10: 1, and then mixed with liquid silicone rubber to form a base mixture in 5: 1, where liquid silicon is mixed. The rubber is a mixture of polymethylideylsiloxane and isocyanate in 1: 1 ratio. The substrate mixture was cast on a hemispherical plastic mold having a diameter of 4 mm, and the cast thickness was 500 μm, and then fed to 70 ° C in an oven, cured 2 h, and formed a curved surface elastic film having stretching properties.

[0058] (6) Subsequently stretched the surface stretch film substrate, on the cylindrical transfer table of a radius of 3 mm, the above unsapetled silicon wafer, the photoresist, the composition of the microlens array inverted, forming micro-lens The lens array is underward, and the commencement is in turn, the combination of the silicon wafer is contacted with the combination of the microlense array with the elastic film stretched into a two-dimensional plane to achieve imprint, and then the silicon wafer and the photoresist The negative mold is peeled off, and the transfer is completed. The elastic substrate to be stretched is formed by the production of the surface of the surface of the surface due to the slow-modified slow shape of its elasticity.

[0059] (7) Receive the light of each sub-eye capture. By the design of the microlens structure of the microlens structure, its focal length is calculated, and the focal surface combination of all childhood will form a hemispherical curved surface. The photosensitive sensor is placed on the position of each sub-eye on the curved surface of the surface, and all of the eyes are spliced together to obtain an intact space. Such as Image 6 Indicated.

[0060] Among them, according to the principle of imaging of the flat convex lens, its focal length is in the formula:

[0061]

[0062] Among them, R is the radius of curvature of the sub-eye, and the refractive index of the child eye. According to the formula, it is estimated that the surface of the photoreceptor of the photoreceptor corresponding to the sub-eye is calculated, and the surface of the photoreceptor surface is attached to the surface of the eye lens according to its focal length. Focus, complete the placement of the receiving surface.

[0063] In summary, the present invention has the following advantages of the method using the method of Example 1, with the following advantages:

[0064] 1. The microlens structure is performed three-dimensional photolithography using a digital micro-mirror DMD digital photolithography, and only a mold is required to obtain a microlens array. The radius of the microlens caliber, the height, and the radius of the reciprocity of the aperture lens are controllable. The relative other manufacturing methods have the advantages of low cost, high efficiency, and highly well-known microlens, and good surface uniformity. At the same time, the use of spacer eye design prevents crosstalk problems when the factor eye is too dense to cause approximation, and improves the imaging quality of the complexion lens.

[0065] 2, the present invention employs a hemispherical elastic film as a substrate, which is used to achieve curved bending of microlens arrays by imprinting transfer. Its operation steps are simple, and after the microlens array bend, the curvature is uniform, and the field of view is large. Relative to other means of changing the base radians by physical means, having a simple structure, low cost, and good base bending and uniformity.

[0066] 3, the present invention employs a photosensitive sensor of the surface focal plane resettile surface focal plane and the number of sub-eyes, which can effectively reduce the defocusing problem generated by the sub-eye imaging when using the planar sensor, and the relative other non-uniform curved surface and sub-structure The method of defocusing, the present invention employs the same size of each sub-dimension, which greatly reduces the difficulty of design and manufacturing of microlens array.

Example Embodiment

[0067] Example 2

[0068] This embodiment provides a method of preparing a surface diaphraglass based on DMD digital photolithography, including the following steps:

[0069] (1) The silicon wafer is selected as the substrate, and the mixed solution of hydrofluoric acid with the hydrofluoride is prepared in the proportion of volume ratio 10: 1.5, and the silicon wafer is placed in a mixed solution for 1 min, followed by flushing the surface of the silicon wafer using flow deionized water. The silicon wafer was placed in an oven for 8 min, thus thoroughly evaporating excess water to ensure drying the surface of the silicon wafer.

[0070] (2) The AZ9260 positive photoresist was at 350 rpm, lasting 30s, and finally coated on the silicon wafer had a thickness of about 20 μm. The photoresist was previously baked, and the process parameters of 120 ° C / 3 min were used, i.e., the silicon wafer after homogenization was placed on a grill plate of a constant temperature of 110 ° C for 3 min. After the baking is over, the silicon wafer is required to stand in a clean environment for a few minutes to cool to the room temperature environment.

[0071] (3) According to the design of the design lens array structure, the gradation coding information corresponding to the DMD microdeter is calculated, and the information is introduced into the DMD to begin to expose the photoresist, and the exposure time needs to be based on the exposure dose and micro-mirror. Light intensity decides. The present embodiment is exposed to 50s. The 1: 1 mixture of the developing fluid and plasma water supporting the photoresist will be developed, and the positive photoresist will remain unexposed. Then, the heat reflow treatment is performed, and the exposure development link has been removed in the exposure development link, thereby increasing the surface smoothness of the processing structure, the temperature of the heat reflow is 115 ° C, the baking time is 3 minutes, resulting in a negative mode of the microlens array .

[0072] (4) After mixing the liquid PDMS and the curing agent at a ratio of 10: 1, the mixed liquid is placed in a vacuum drying cabinet. After the bubbles are dissipated, the mixed liquid is slowly injected into the negative mold, and then placed In an oven at 70 ° C, the liquid is cured to form a plane microlens array. All sub-eyes in the array have the same size. The center of the microlens array is primary, the second-grade binds are arranged in circular shaped eyes and are arranged around the primary sub-eye, and the three-stage children are also rounded at the same time as a one-stage eyed eye. The circle is arranged outside the eyes. With this type, the microlens array contains a total of nine-level eyes.

[0073] (5) Making a surface hemispherical force film, a mixed solution is mixed with a liquid PDMS and a silicone resin solution in a proportion of 9: 1, and then mixed with liquid silicone rubber to form a base mixture at 5: 1, where liquid silicon is mixed. The rubber is a mixture of polymethylideylsiloxane and isocyanate in 1: 1 ratio. The base mixture was cast on a hemispherical plastic mold having a diameter of 4 mm, and the casting thickness was 500 μm, and then it was fed to 65 ° C in an oven, solidified for 2 h, and formed a curved surface elastic film having stretching properties.

[0074] (6) Subsequently stretched the surface stretch film substrate, on the cylindrical transfer table of a radius of 3 mm, the above unsapetled silicon wafer, the photoresist, the composition of the microlens array inverted, forming micro-lens The lens array is underward, and the commencement is in turn, the combination of the silicon wafer is contacted with the combination of the microlense array with the elastic film stretched into a two-dimensional plane to achieve imprint, and then the silicon wafer and the photoresist The negative mold is peeled off, and the transfer is completed. The elastic substrate to be stretched is formed by the production of the surface of the surface of the surface due to the slow-modified slow shape of its elasticity.

[0075] (7) Receive the light of each sub-eye capture. By the design of the microlens structure of the microlens structure, its focal length is calculated, and the focal surface combination of all childhood will form a hemispherical curved surface. The photosensitive sensor is placed on the position of each sub-eye on the curved surface of the surface, and all of the eyes are spliced together to obtain an intact space.

Example Embodiment

[0076] Example 3

[0077] This embodiment provides a method of preparing a surface diaphraglass based on DMD digital photolithography, including the following steps:

[0078](1) Select the silicon wafer as the substrate, prepare the mixed solution of hydrofluoric acid with the hydrofluoride in the proportion of volume ratio 10: 1, and placed the silicon wafer to soak for 2 min, then the surface of the wafer is flushed with flow deionized water, The silicon wafer was placed in an oven for 10 min, thereby thoroughly evaporating the excess water to ensure the surface of the silicon wafer.

[0079] (2) The AZ9260 positive photoresist was at 400 rpm, lasting 30s, and finally coated on the silicon film having a thickness of about 20 μm. The follow-up of the photoresist was previously baked, and the process parameters of 120 ° C / 3 min were used, that is, the silicon wafer to homogenate was placed on the grilled plate of the constant temperature 120 ° C for 3 min. After the baking is over, the silicon wafer is required to stand in a clean environment for a few minutes to cool to the room temperature environment.

[0080] (3) According to the design of the design lens array structure, the gradation coding information corresponding to the DMD microdeter is calculated, and the information is introduced into the DMD to begin to expose the photoresist, and the exposure time needs to be based on the exposure dose and micro-mirror. Light intensity decides. The present embodiment is exposed to 50s. The 1: 1 mixture of the developing fluid and plasma water supporting the photoresist will be developed, and the positive photoresist will remain unexposed. Then, the heat reflow treatment is performed, and the inclusion of the rubbing layer that has not been completely detached in the exposure development is removed, thereby increasing the surface smoothness of the machining structure, the temperature of the heat reflow is 130 ° C, the baking time is 2 min, and the negative mode of the microlens array is obtained. .

[0081] (4) After mixing the liquid PDMS and silicone resin solution at a ratio of 10: 1, the mixed liquid is placed in a vacuum drying cabinet, and after the bubbles are dissipated, the mixed liquid is slowly injected into the negative mold, and then Placed in an oven at 70 ° C, to be mixed with liquid, form a plane microlens array. All sub-eyes in the array have the same size. The center of the microlens array is primary, the second-grade binds are arranged in circular shaped eyes and are arranged around the primary sub-eye, and the three-stage children are also rounded at the same time as a one-stage eyed eye. The circle is arranged outside the eyes. With this type, the microlens array contains a total of nine-level eyes.

[0082] (5) Production of a surface hemispherical force film, a mixed solution is formed in a proportion of 10: 1 in a ratio of 10: 1, and then mixed with liquid silicone rubber to form a base mixture in 5: 1, where liquid silicon is mixed. The rubber is a mixture of polymethylideylsiloxane and isocyanate in 1: 1 ratio. The base mixture was cast on a hemispherical plastic mold having a diameter of 4 mm, and the cast thickness was 500 μm, and then fed to 75 ° C in an oven, cured 2 h, and formed a curved surface elastic film having stretching properties.

[0083] (6) Subsequently stretched the surface stretch film substrate, on the cylindrical transfer table of a radius of 3 mm, the above unsapetled silicon wafer, the photoresist, the composition of the microlens array inverted, forming micro-lens The lens array is underward, and the commencement is in turn, the combination of the silicon wafer is contacted with the combination of the microlense array with the elastic film stretched into a two-dimensional plane to achieve imprint, and then the silicon wafer and the photoresist The negative mold is peeled off, and the transfer is completed. The elastic substrate to be stretched is formed by the production of the surface of the surface of the surface due to the slow-modified slow shape of its elasticity.

[0084] (7) Receive the light of each sub-eye capture. By the design of the microlens structure of the microlens structure, its focal length is calculated, and the focal surface combination of all childhood will form a hemispherical curved surface. The photosensitive sensor is placed on the position of each sub-eye on the curved surface of the surface, and all of the eyes are spliced together to obtain an intact space.

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Classification and recommendation of technical efficacy words

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Curved fly's-eye lens based on DMD digital photoetching and preparation method of curved fly's-eye lens

AI-Extracted Technical Summary

Problems solved by technology

Method used

Abstract

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Examples

Example Embodiment

Example Embodiment

Example Embodiment

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Description & Claims & Application Information

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