CN115598747A - Ultrathin multi-focal-length lens and manufacturing method thereof - Google Patents
Ultrathin multi-focal-length lens and manufacturing method thereof Download PDFInfo
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- CN115598747A CN115598747A CN202211312452.4A CN202211312452A CN115598747A CN 115598747 A CN115598747 A CN 115598747A CN 202211312452 A CN202211312452 A CN 202211312452A CN 115598747 A CN115598747 A CN 115598747A
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B3/00—Simple or compound lenses
- G02B3/02—Simple or compound lenses with non-spherical faces
- G02B3/08—Simple or compound lenses with non-spherical faces with discontinuous faces, e.g. Fresnel lens
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B3/00—Simple or compound lenses
- G02B3/10—Bifocal lenses; Multifocal lenses
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/0002—Lithographic processes using patterning methods other than those involving the exposure to radiation, e.g. by stamping
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/70—Microphotolithographic exposure; Apparatus therefor
- G03F7/70383—Direct write, i.e. pattern is written directly without the use of a mask by one or multiple beams
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Abstract
The invention discloses an ultrathin multi-focal-length lens and a manufacturing method thereof, wherein the ultrathin multi-focal-length lens comprises an upper half area Fresnel lens and a lower half area Fresnel lens, semicircular areas are cut out from the upper half area Fresnel lens and the lower half area Fresnel lens, the sections of the upper half area Fresnel lens and the lower half area Fresnel lens are spliced and combined, the focal lengths of the upper half area Fresnel lens and the lower half area Fresnel lens are different, and the surfaces of the upper half area Fresnel lens and the lower half area Fresnel lens are provided with ring belt structures. The Fresnel lens is characterized in that a plurality of curved surfaces are arranged on the surface of the Fresnel lens, and the curved surfaces of the Fresnel lens are respectively provided with a plurality of equal-thickness sections. Compared with the traditional gradual change type multi-focal-length lens, the thickness of the lens is greatly reduced, the profile is more regular, the size is smaller, and the lens has the advantage of multiple purposes.
Description
Technical Field
The invention relates to a lens, in particular to an ultrathin multi-focal-length lens and a manufacturing method thereof.
Background
The Fresnel lens technology adopted by the invention is a micro-optical technology, and the traditional lens is subjected to curved surface segmentation to form a plurality of annular belt structures with equal thickness and distributed on a plane material, so that the aim of reducing the thickness of the lens is fulfilled.
On the other hand, laser direct writing is one of the main techniques for manufacturing diffractive optical elements, and a multi-step continuous phase relief microstructure can be directly written on the surface of the photoresist. Laser direct writing is the process of exposing the resist material on the surface of the substrate with variable laser beam in variable dosage and developing to form required relief contour on the resist surface. The basic working principle of the laser direct writing system is that a computer controls high-precision laser beam to scan, and any designed pattern is directly exposed and written on the photoresist, so that the designed pattern is directly transferred to a mask.
The nano-imprinting technology is a novel micro-nano processing technology. The technology achieves ultrahigh resolution by means of mechanical transfer. Since the nanoimprint technology does not use visible light or ultraviolet light to process patterns, but uses mechanical means to transfer patterns, the method can achieve high resolution. The highest resolution can reach 2 nanometers. In addition, the template can be repeatedly used, thereby undoubtedly greatly reducing the processing cost and effectively shortening the processing time. Therefore, the nanoimprint technology has the technical advantages of ultrahigh resolution, easiness in mass production, low cost and high consistency.
Disclosure of Invention
In order to overcome the defects and shortcomings in the prior art, the invention aims to provide an ultrathin multi-focal-length lens and a manufacturing method thereof.
The purpose of the invention is realized by the following technical scheme: the utility model provides an ultra-thin many focal length lens, includes half district fresnel lens and half district fresnel lens down, half district fresnel lens on with half district fresnel lens all intercepts semicircle region down, half district fresnel lens on with half district fresnel lens's cross-section is spliced the combination down, half district fresnel lens on with half district fresnel lens's focus is different down. The combination of the two surface-shaped Fresnel lenses can be selected at will.
As an improvement of the ultrathin multi-focal-length lens, the surfaces of the upper half area Fresnel lens and the lower half area Fresnel lens are both provided with ring-shaped structures, and the curved surface shapes of the upper half area Fresnel lens and the lower half area Fresnel lens are different.
As an improvement of the ultrathin multi-focal-length lens, the annular belt structure comprises a plurality of sections with equal thickness, the sections with equal thickness are formed by splitting the curved surface shape of a common lens, and the sections with equal thickness are distributed on a plane material from inside to outside.
As an improvement of the ultrathin multi-focal-length lens, each girdle structure is provided with a tooth socket, the number of the girdle structures is selected according to the depth of the tooth socket, the depth of the tooth socket is not more than 10 micrometers, and the number of the girdle structures is 180-200 rings.
As an improvement of the ultrathin multi-focal-length lens, the depth of the tooth grooves is larger, the number of the ring belt structures is larger, the depth of the tooth grooves is smaller, and the number of the ring belt structures is smaller. The depth of the tooth grooves is preferably 2-3 microns, and the small depth of the tooth grooves can avoid light intensity loss caused by that light rays are trapped inside the tooth grooves and reflected back and forth when passing through the lens.
As an improvement of the ultrathin multi-focal-length lens, the distance of a focusing point of parallel light passing through the Fresnel lens in the upper half area is longer than that of the focusing point of the parallel light passing through the Fresnel lens in the lower half area, the focal lengths of the Fresnel lens in the upper half area and the Fresnel lens in the lower half area can be adjusted by adjusting surface shape parameters, and the surface shape parameters comprise curvature radius and high-order correction coefficient. The surface shape corrected by the correction coefficient has better light gathering performance, thereby enhancing the imaging quality, ensuring the performance and reducing the complexity of the surface shape.
As an improvement of the ultrathin multi-focal-length lens, the girdle structure is manufactured by adopting a process flow combining a high-precision laser direct writing technology and a nano-imprinting technology.
The invention also aims to provide a manufacturing method of the ultrathin multi-focal-length lens, which comprises the following steps:
s1: coating glue, spin-coating photoresist on a silicon wafer,
s2: pre-drying, namely placing the silicon wafer on a heating plate to soft-dry the photoresist so that the photoresist has certain hardness;
s3: exposing, namely exposing the photoresist by using laser direct writing equipment, and controlling the exposure depth by adjusting the exposure power;
s4: developing, after exposure is finished, developing the photoresist to obtain an annular belt structure of the lens;
s5: and (5) drying, namely hard drying the product obtained in the step (S4) to obtain a lens mold for nanoimprint;
s6: and (4) transfer printing, transferring the lens structure on the mold to organic glass (PMMA) by using a nano-imprinting device, and demolding to obtain the lens.
As an improvement of the manufacturing method of the ultrathin multi-focal-length lens, the photoresist in the step S1 is selected to be the photoresist S1818, two-stage spin coating is carried out, the thickness of the photoresist film after the photoresist coating is finished is 2.5 micrometers, and the laser exposure dose in the step S3 is 1276 muJ/mm 2 The exposure resolution is 300nm, the scanning speed is 200mm/S, the development in the step S4 adopts spray development, and the development time is 35S according to the photoresist film thickness of 2.5 microns.
As an improvement of the manufacturing method of the ultrathin multi-focal-length lens, the temperature of the heating plate for front drying is 110 ℃, the time for front drying is 1min, the temperature of the heating plate for rear drying is 110 ℃, the time for rear drying is 30S, and the transfer printing in the step S6 adopts organic glass (PMMA) as a transfer printing substrate, so that the lens can be directly formed, and the large-scale manufacturing is convenient.
The invention has the beneficial effects that: the Fresnel lens has a special annular structure, so that a common lens curved surface is separated into a plurality of sections with equal thickness, and meanwhile, a plurality of curved surfaces can be separated from the same plane material, thereby achieving the purpose of reducing the thickness of the lens. Compared with the traditional gradual change type multi-focal-length lens, the thickness of the lens is greatly reduced, the profile is more regular, the size is smaller, and the lens has the advantage of multiple purposes.
Drawings
FIG. 1 is a schematic diagram of a splicing structure of an upper half area Fresnel lens and a lower half area Fresnel lens according to the present invention;
FIG. 2 is a schematic diagram of the distribution of the Fresnel lens annular belt structure of the upper half area of the present invention;
FIG. 3 is a schematic diagram of the distribution of the Fresnel lens annular belt structure of the lower half area of the present invention;
FIG. 4 is a schematic focusing diagram of the present invention;
FIG. 5 is a process flow diagram of the present invention;
the reference signs are: 1. the Fresnel lens comprises an upper half area Fresnel lens 2, a lower half area Fresnel lens 3 and an annular belt structure.
Detailed Description
The technical solutions in the embodiments of the present invention will be described below clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that all directional indicators (such as up, down, left, right, front, back \8230;) in the embodiments of the present invention are only used to explain the relative position relationship between the components, the motion situation, etc. in a specific posture (as shown in the attached drawings), and if the specific posture is changed, the directional indicator is changed accordingly.
In addition, the descriptions related to "first", "second", etc. in the present invention are for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the feature. In addition, the technical solutions in the embodiments may be combined with each other, but it must be based on the realization of the technical solutions by those skilled in the art, and when the technical solutions are contradictory to each other or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.
As shown in fig. 1 to 4, an ultrathin multi-focal-length lens includes an upper half-zone fresnel lens 1 and a lower half-zone fresnel lens 2, where the upper half-zone fresnel lens 1 and the lower half-zone fresnel lens 2 both intercept a semicircular region, the sections of the upper half-zone fresnel lens 1 and the lower half-zone fresnel lens 2 are spliced and combined, and the focal lengths of the upper half-zone fresnel lens 1 and the lower half-zone fresnel lens 2 are different. The Fresnel lenses with two surface shapes can be arbitrarily selected to be combined.
Preferably, the surfaces of the upper half area fresnel lens 1 and the lower half area fresnel lens 2 are both provided with the ring belt structure 3, and the curved surface shapes of the upper half area fresnel lens 1 and the lower half area fresnel lens 2 are different.
Preferably, the girdle structure 3 comprises a plurality of sections with equal thickness, the sections with equal thickness are formed by splitting a curved surface shape of a common lens, and the sections with equal thickness are distributed on the plane material from inside to outside.
Preferably, each ring belt structure 3 is provided with tooth grooves, the number of the ring belt structures 3 is selected according to the depth of the tooth grooves, the depth of the tooth grooves is not more than 10 microns, and the number of the ring belt structures is 180-200 rings.
Preferably, the greater the depth of the gullet and the greater the number of girdle structures, the smaller the depth of the gullet and the fewer the number of girdle structures. The depth of the tooth grooves is preferably 2-3 microns, and the small depth of the tooth grooves can avoid light intensity loss caused by that light rays are trapped inside the tooth grooves and reflected back and forth when passing through the lens.
Preferably, the distance of the focusing point of the parallel light passing through the upper half area Fresnel lens is longer than that of the focusing point of the parallel light passing through the lower half area Fresnel lens, the focal lengths of the upper half area Fresnel lens and the lower half area Fresnel lens can be adjusted by adjusting surface shape parameters, and the surface shape parameters comprise curvature radius and high-order correction coefficients. The surface shape corrected by the correction coefficient has better light gathering performance, thereby enhancing the imaging quality, ensuring the performance and reducing the complexity of the surface shape.
Preferably, the girdle structure is manufactured by adopting a process flow combining a high-precision laser direct writing technology and a nano-imprinting technology.
As shown in fig. 5, a method for manufacturing an ultrathin multi-focal-length lens includes the following steps:
s1: coating glue, namely spin-coating photoresist on a silicon wafer, selecting S1818 photoresist for the photoresist, and spin-coating at two stages, wherein the thickness of the photoresist film after coating glue is 2.5 microns;
s2: pre-drying, namely placing the silicon wafer on a heating plate to soft-dry the photoresist so that the photoresist has certain hardness; the temperature of the heating plate for pre-drying is 110 ℃, and the time for pre-drying is 1min;
s3: exposing, namely exposing the photoresist by using laser direct writing equipment, and controlling the exposure depth by adjusting the exposure power; laser exposure dose 1276 muJ/mm 2 Exposure resolution is 300nm, and scanning speed is 200mm/s; photoetching the designed three-dimensional annular structure of the lens to a photoresist film layer by using variable dose exposure of a laser direct writing technology;
s4: developing, after exposure is finished, developing the photoresist to obtain an annular belt structure of the lens; spray development is adopted for development, and the development time is selected to be 35s according to the thickness of the photoresist film of 2.5 micrometers;
s5: performing post-drying, namely performing hard drying on the product obtained in the step S4 to obtain a lens mold for nanoimprint, wherein the temperature of a heating plate for post-drying is 110 ℃, and the time for post-drying is 30 seconds;
s6: and (4) transfer printing, transferring the lens structure on the mold to organic glass (PMMA) by using a nano-imprinting device, and demolding to obtain the lens. The transfer printing adopts organic glass (PMMA) as a transfer printing substrate, can directly form a lens and is convenient for large-scale manufacturing.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and arrangements of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (9)
1. The ultrathin multi-focal-distance lens is characterized by comprising an upper half area Fresnel lens and a lower half area Fresnel lens, wherein semicircular areas are cut out from the upper half area Fresnel lens and the lower half area Fresnel lens, the sections of the upper half area Fresnel lens and the lower half area Fresnel lens are spliced and combined, and the focal lengths of the upper half area Fresnel lens and the lower half area Fresnel lens are different;
the surface of the upper half area Fresnel lens and the surface of the lower half area Fresnel lens are both provided with ring belt structures, and the surface shapes of the curved surfaces of the upper half area Fresnel lens and the lower half area Fresnel lens are different.
2. The ultra-thin multi-focal-length lens of claim 1, wherein the annular zone structure comprises a plurality of sections of equal thickness, the sections of equal thickness are formed by splitting a curved surface of a common lens, and the sections of equal thickness are distributed on a plane material from inside to outside.
3. The ultra-thin, multi-focal lens of claim 2, wherein each of the girdle structures has a gullet, wherein the number of girdle structures is selected based on the depth of the gullet, wherein the depth of the gullet is not more than 10 μm, and wherein the number of girdle structures is 180-200 rings.
4. The ultra-thin multi-focal lens of claim 3, wherein the greater the depth of the gullets and the greater the number of girdle structures, the smaller the depth of the gullets and the fewer the number of girdle structures.
5. The ultrathin multi-focal-length lens as recited in claim 4, wherein the distance of the focusing point of the parallel light passing through the upper half area Fresnel lens is longer than the distance of the focusing point of the parallel light passing through the lower half area Fresnel lens, and the focal lengths of the upper half area Fresnel lens and the lower half area Fresnel lens can be adjusted by adjusting surface shape parameters, wherein the surface shape parameters comprise curvature radius and high-order correction coefficients.
6. The ultra-thin multi-focal-length lens of claim 4, wherein the ring belt structure is manufactured by a process flow combining a high precision laser direct writing technology and a nano-imprinting technology.
7. A method for manufacturing an ultrathin multi-focal-length lens is characterized by comprising the following steps:
s1: coating glue, spin-coating photoresist on a silicon wafer,
s2: pre-drying, namely placing the silicon wafer on a heating plate to soft-dry the photoresist so that the photoresist has certain hardness;
s3: exposing, namely exposing the photoresist by using laser direct writing equipment, and controlling the exposure depth by adjusting the exposure power;
s4: developing, after exposure is finished, developing the photoresist to obtain an annular belt structure of the lens;
s5: and (5) drying, namely hard drying the product obtained in the step (S4) to obtain a lens mold for nanoimprint;
s6: and (4) transfer printing, transferring the lens structure on the mold to organic glass (PMMA) by using a nano-imprinting device, and demolding to obtain the lens.
8. The method for manufacturing the ultrathin multi-focal-length lens as claimed in claim 7, wherein the photoresist in the step S1 is selected from an S1818 photoresist, the two-stage spin coating is performed, the thickness of the photoresist film after the photoresist coating is finished is 2.5 microns, and the laser exposure dose in the step S3 is 1276 muJ/mm 2 The exposure resolution is 300nm, the scanning speed is 200mm/S, the step S4 adopts spray development, and the developing time is 35S according to the thickness of the photoresist film of 2.5 microns.
9. The method for manufacturing an ultrathin multi-focal-length lens as claimed in claim 7, wherein the temperature of the heating plate for front drying is 110 ℃, the time for front drying is 1min, the temperature of the heating plate for back drying is 110 ℃, the time for back drying is 30S, and the transfer printing in the step S6 adopts machine glass (PMMA) as a transfer printing substrate, so that the lens can be directly formed, and the large-scale manufacturing is convenient.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211312452.4A CN115598747A (en) | 2022-10-25 | 2022-10-25 | Ultrathin multi-focal-length lens and manufacturing method thereof |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202211312452.4A CN115598747A (en) | 2022-10-25 | 2022-10-25 | Ultrathin multi-focal-length lens and manufacturing method thereof |
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| Publication Number | Publication Date |
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| CN115598747A true CN115598747A (en) | 2023-01-13 |
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| CN202211312452.4A Pending CN115598747A (en) | 2022-10-25 | 2022-10-25 | Ultrathin multi-focal-length lens and manufacturing method thereof |
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- 2022-10-25 CN CN202211312452.4A patent/CN115598747A/en active Pending
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