Optical module and preparation method and application thereof

Abstract

The invention belongs to the technical field of eye movement tracking, and particularly relates to an optical module and a preparation method and application thereof. According to the preparation method provided by the invention, a nanoimprint technology is combined with a cold plating process, film plating is performed after imprint, a single-surface type is imprint on the surface of wafer-level optical glass by using glue, all the surface types are stacked by using bonding glue, and then a visible light cut-off film is plated on the surface of a product by using the cold plating process. According to the preparation method provided by the invention, the surface type of the lens is effectively prevented from being changed due to the fact that glue is heated in the coating process, and the problems that coated glass is warped after imprinting, imprinting alignment cannot be measured, edge grabbing is not easy during cutting and the like are solved. The prepared optical module shared by miniature eye movement tracking and iris recognition has the advantages of being small in size, low in cost, high in production efficiency and good in performance consistency.

Description

Technical Field

[0001] The present invention belongs to the technical field of eye movement tracking, and particularly relates to an optical module, a preparation method thereof, and an application thereof. Background Art

[0002] An eye movement tracking module is a professional technical module for obtaining the fixation position and attention of the human eye, which has the advantages of high precision, low latency, easy integration and application, etc., and has broad application prospects in the fields of VR / AR, advertising and marketing, medical health, etc.

[0003] At present, the preparation of most eye movement tracking modules has the disadvantages of high production cost and poor performance consistency. Summary of the Invention

[0004] The purpose of the present invention is to provide an optical module, a preparation method thereof, and an application thereof. The optical module obtained by the preparation method provided by the present invention has low cost and good performance consistency.

[0005] In order to achieve the above purpose, the present invention provides the following technical solutions:

[0006] The present invention provides a preparation method of an optical module, comprising the following steps:

[0007] Preparing a sub-mold from a metal mold, the metal mold comprising a first metal mold, a second metal mold, a third metal mold, and a fourth metal mold, the first metal mold, the second metal mold, the third metal mold, and the fourth metal mold having lens structure patterns with different shapes, the sub-mold comprising a first sub-mold having a pattern opposite to that of the first metal mold, a second sub-mold having a pattern opposite to that of the second metal mold, a third sub-mold having a pattern opposite to that of the third metal mold, and a fourth sub-mold having a pattern opposite to that of the fourth metal mold;

[0008] Dispensing imprinting glue on one surface of a first wafer, a second wafer, a third wafer, and a fourth wafer, and respectively performing imprinting using the first sub-mold, the second sub-mold, the third sub-mold, and the fourth sub-mold to obtain a first wafer surface type product, a second wafer surface type product, a third wafer surface type product, and a fourth wafer surface type product; the other surface of the first wafer and the third wafer has a photoresist pattern, the photoresist pattern on the other surface of the first wafer has the same array arrangement spacing as the pattern of the first sub-mold, and the photoresist pattern on the other surface of the third wafer has the same array arrangement spacing as the pattern of the third sub-mold;

[0009] Bonding the imprinting surfaces of the first wafer surface type product, the second wafer surface type product, the third wafer surface type product, the fourth wafer surface type product, and a fifth wafer using a bonding glue to obtain a post-imprinting product;

[0010] A visible light cutoff film is deposited on the other surface of the fifth wafer in the post - imprint product by cold plating to obtain a coated product, and the temperature of the cold plating is < 30°C;

[0011] The coated product is subjected to post - coating treatment to obtain the optical module.

[0012] Preferably, each of the metal molds has 25 lens structure patterns.

[0013] Preferably, the light - leakage area in the photoresist pattern on the other surface of the first wafer is a rectangular area with the same length and width as a single lens on the first sub - mold; the light - shielding area in the photoresist pattern on the other surface of the first wafer corresponds to the cutting area between single lenses on the first sub - mold;

[0014] The light - leakage area in the photoresist pattern on the other surface of the third wafer is a rectangular area with the same length and width as a single lens on the third sub - mold; the light - shielding area in the photoresist pattern on the other surface of the third wafer corresponds to the cutting area between single lenses on the third sub - mold.

[0015] Preferably, the refractive index of the imprint surface of the first wafer - shaped product and the imprint surface of the fourth wafer - shaped product is 1.5;

[0016] The refractive index of the imprint surface of the second wafer - shaped product and the imprint surface of the third wafer - shaped product is 1.7.

[0017] Preferably, the bonding includes the following steps:

[0018] After applying glue to the imprint surface of the first wafer - shaped product, it is bonded pairwise with the imprint surface of the second wafer - shaped product and then cured to obtain a first bonding intermediate product;

[0019] After applying glue to the imprint surface of the fourth wafer - shaped product, it is bonded pairwise with the fifth wafer and then cured to obtain a second bonding intermediate product;

[0020] After applying glue to the imprint surface of the third wafer - shaped product, it is bonded pairwise with the other surface of the fourth wafer in the second bonding intermediate product and then cured to obtain a third bonding intermediate product;

[0021] After applying glue to the other surface of the second wafer in the first bonding intermediate product, it is bonded pairwise with the other surface of the third wafer in the third bonding intermediate product, and then cured and baked in sequence to obtain the post - imprint product.

[0022] Preferably, the preparation method of the sub - mold includes the following steps:

[0023] Apply the imprinting glue on the side of the metal mold with the lens structure pattern, add the drainage glue at the center point of the quartz glass, and then perform imprinting to obtain a sub-mold with a pattern opposite to that of the metal mold; the sub-mold includes quartz glass and a soft template provided on the surface of the quartz glass, and the soft template has a pattern opposite to that of the metal mold.

[0024] Preferably, the imprinting glue is polydimethylsiloxane imprinting glue.

[0025] Preferably, the evaporation source for cold plating includes Ti 3 O 5 and SiO 2 ; the evaporation rate of the Ti 3 O 5 is The evaporation rate of the SiO 2 is During the cold plating process, the substrate is not heated, and the cold plating time is 6 - 7 h.

[0026] The present invention provides an optical module prepared by the preparation method described in the above technical solution, including a first wafer, a first imprinting glue residue layer, a first bonding layer, a second imprinting glue residue layer, a second wafer, a second bonding layer, a third wafer, a third imprinting glue residue layer, a third bonding layer, a fourth wafer, a fourth imprinting glue residue layer, a fourth bonding layer, a fifth wafer, and a visible light cut-off layer stacked in sequence.

[0027] The present invention provides an application of the optical module described in the above technical solution in a micro eye movement tracking and / or iris recognition module.

[0028] The present invention provides a preparation method for an optical module. The preparation method provided by the present invention adopts a nanoimprinting technology combined with a cold plating process, first imprints and then coats a film. A single-sided surface type is imprinted on the surface of the wafer-level optical glass using glue, and each surface type is stacked using a bonding glue. Then, a visible light cut-off film is coated on the surface of the product using a cold plating process. The preparation method provided by the present invention effectively avoids the change of the lens surface type due to heat during the film coating process, solves problems such as warping of the glass after imprinting and then coating, inability to measure the imprinting alignment, and difficulty in gripping the edge during cutting. The optical module for micro eye movement tracking and iris recognition prepared by the present invention has the advantages of small volume, low cost, high production efficiency, and good performance consistency.

[0029] Furthermore, in the present invention, the refractive index of the imprinting surface of the first wafer surface type product and the imprinting surface of the fourth wafer surface type product is 1.5; the refractive index of the imprinting surface of the second wafer surface type product and the imprinting surface of the third wafer surface type product is 1.7. The present invention uses a high transmittance imprinting glue to imprint a single-sided surface type, which is more conducive to the alignment and thickness measurement during the nanoimprinting process, and obtains an optical module with good performance consistency. Brief Description of the Drawings

[0030] Figure 1 It is a flowchart of the preliminary material preparation stage in Embodiment 1 of the present invention;

[0031] Figure 2 It is a flowchart of the imprinting process in Embodiment 1 of the present invention;

[0032] Figure 3 It is a flowchart of the coating process in Embodiment 1 of the present invention;

[0033] Figure 4 It is a schematic diagram of the coating device in Embodiment 1 of the present invention;

[0034] Figure 5 It is a flowchart of the process after coating in Embodiment 1 of the present invention;

[0035] Figure 6 It is a schematic diagram of the lens product structure prepared in Embodiment 1 of the present invention;

[0036] In the figure: 1 is the substrate heating source, 2 is the umbrella frame, 3 is the vacuum chamber, 4 is the exhaust port, 5 is the evaporation material, 6 is the evaporation source, 7 is the film thickness gauge, 8 is the first wafer, 9 is the first residual layer of imprinting glue, 10 is the first bonding layer, 11 is the second residual layer of imprinting glue, 12 is the second wafer, 13 is the second bonding layer, 14 is the third wafer, 15 is the third residual layer of imprinting glue, 16 is the third bonding layer, 17 is the fourth wafer, 18 is the fourth residual layer of imprinting glue, 19 is the fourth bonding layer, 20 is the fifth wafer, and 21 is the visible light cutoff film. Detailed Embodiments

[0037] The present invention provides a method for preparing an optical module, comprising the following steps:

[0038] Preparing sub-molds from metal molds, the metal molds including a first metal mold, a second metal mold, a third metal mold, and a fourth metal mold, the first metal mold, the second metal mold, the third metal mold, and the fourth metal mold having lens structure patterns with different shapes, and the sub-molds including a first sub-mold having a pattern opposite to that of the first metal mold, a second sub-mold having a pattern opposite to that of the second metal mold, a third sub-mold having a pattern opposite to that of the third metal mold, and a fourth sub-mold having a pattern opposite to that of the fourth metal mold;

[0039] Imprint glue is disposed on one surface of the first wafer, the second wafer, the third wafer, and the fourth wafer. Imprinting is performed using the first sub-mold, the second sub-mold, the third sub-mold, and the fourth sub-mold respectively to obtain a first wafer surface profile product, a second wafer surface profile product, a third wafer surface profile product, and a fourth wafer surface profile product; on the other surface of the first wafer and the third wafer, there are photoresist patterns. The photoresist pattern on the other surface of the first wafer has the same pattern array arrangement pitch as that of the first sub-mold, and the photoresist pattern on the other surface of the third wafer has the same pattern array arrangement pitch as that of the third sub-mold;

[0040] The imprinted surfaces of the first wafer surface profile product, the second wafer surface profile product, the third wafer surface profile product, the fourth wafer surface profile product, and the fifth wafer are bonded with bonding glue to obtain a post-imprint product;

[0041] A visible light cutoff film is deposited on the other surface of the fifth wafer in the post-imprint product by means of cold plating to obtain a post-coated product, and the temperature of the cold plating < 30°C;

[0042] The post-coated product is subjected to post-coating treatment to obtain the optical module.

[0043] In the present invention, unless otherwise specified, all preparation raw materials / components are commercially available products well-known to those skilled in the art.

[0044] In the present invention, sub-molds are prepared from metal molds. The metal molds include a first metal mold, a second metal mold, a third metal mold, and a fourth metal mold. The first metal mold, the second metal mold, the third metal mold, and the fourth metal mold have lens structure patterns with different shapes. The sub-molds include a first sub-mold having a pattern opposite to that of the first metal mold, a second sub-mold having a pattern opposite to that of the second metal mold, a third sub-mold having a pattern opposite to that of the third metal mold, and a fourth sub-mold having a pattern opposite to that of the fourth metal mold. In the present invention, the preparation method of the metal mold preferably includes: turning a metal substrate with a nickel plating layer on its surface to obtain the metal mold. Each of the metal molds has 25 lens structure patterns. The lens structures on the metal mold are arranged in an array. The first metal mold, the second metal mold, the third metal mold, and the fourth metal mold are metal molds with four different surface profiles.

[0045] In the present invention, the preparation method of the sub-mold preferably includes the following steps:

[0046] Dispense an imprinting adhesive on one side of the metal mold with a lens structure pattern, add a flow guiding adhesive at the center point of the quartz glass, and then perform imprinting to obtain a sub-mold with a pattern opposite to that of the metal mold; the sub-mold includes quartz glass and a soft template provided on the surface of the quartz glass, and the soft template has a pattern opposite to that of the metal mold. In the present invention, it is preferred to pre-treat the quartz glass, and the pre-treatment is preferably: performing plasma cleaning on the surface of the quartz glass. The present invention has no special requirements for the specific implementation process of the plasma cleaning. The dispensing is preferably to pour a layer of imprinting adhesive at the center position on one side of the metal mold with a lens structure pattern. The imprinting adhesive is a polydimethylsiloxane imprinting glue. The imprinting is performed using an imprinting device, and the imprinting device can be a SUSS imprinting device. In the present invention, it is preferred to transfer the pre-set nano-structure pattern on the metal mold to the soft template through imprinting to obtain a transfer template with a reverse structure pattern, that is, a sub-mold. The soft template is an imprinting adhesive template.

[0047] After obtaining the sub-mold, in the present invention, dispense an imprinting glue on one surface of the first wafer, the second wafer, the third wafer, and the fourth wafer, and perform imprinting using the first sub-mold, the second sub-mold, the third sub-mold, and the fourth sub-mold respectively to obtain a first wafer surface type product, a second wafer surface type product, a third wafer surface type product, and a fourth wafer surface type product; the other surfaces of the first wafer and the third wafer have photoresist patterns, the photoresist pattern on the other surface of the first wafer has the same array arrangement spacing as the pattern of the first sub-mold, and the photoresist pattern on the other surface of the third wafer has the same array arrangement spacing as the pattern of the third sub-mold. In the present invention, the light leakage area in the photoresist pattern on the other surface of the first wafer is a rectangular area with the same length and width as a single lens on the first sub-mold; the light shielding area in the photoresist pattern on the other surface of the first wafer corresponds to the cutting area between a single lens and a single lens on the first sub-mold. The light leakage area in the photoresist pattern on the other surface of the third wafer is a rectangular area with the same length and width as a single lens on the third sub-mold; the light shielding area in the photoresist pattern on the other surface of the third wafer corresponds to the cutting area between a single lens and a single lens on the third sub-mold.

[0048] In the present invention, the first wafer, the second wafer, the third wafer, and the fourth wafer are all wafer-level optical glasses (i.e., glass wafers).

[0049] In the present invention, the preparation method of the first wafer and the third wafer preferably includes the following steps: coat a photoresist on the other surface of the first wafer or the third wafer, and then obtain a photoresist pattern through exposure and development. Before coating the photoresist, the present invention preferably cleans the first wafer or the third wafer. The present invention has no special requirements for the specific implementation manners of the exposure and development.

[0050] In the present invention, the first wafer surface type product, the second wafer surface type product, the third wafer surface type product, and the fourth wafer surface type product are preferably prepared by a single-sided imprinting method. The single-sided imprinting is preferably carried out using an imprinting device, and the imprinting device can be a SUSS imprinting device. In the present invention, the specific implementation manner of the single-sided imprinting preferably includes: vacuum-adsorbing the first wafer, the second wafer, the third wafer, or the fourth wafer and the corresponding sub-molds at the lower and upper positions of the imprinting machine respectively; setting imprinting glue in the middle of one surface of the first wafer, the second wafer, the third wafer, or the fourth wafer, setting the offset, GAP value, and imprinting speed according to the residual layer thickness of the structure design, and transferring the reverse pattern of the structure on the stamp to the upper surface of the imprinting glue layer of the first wafer, the second wafer, the third wafer, or the fourth wafer (wafer glass), so as to obtain a single-sided surface with a lens structure on the upper surface of the imprinting glue layer, and obtaining the first wafer surface type product, the second wafer surface type product, the third wafer surface type product, and the fourth wafer surface type product.

[0051] After obtaining the first wafer surface type product, the second wafer surface type product, the third wafer surface type product, and the fourth wafer surface type product, the present invention preferably selects five points, namely, the upper, middle, lower, left, and right points on the imprinting surfaces of the first wafer surface type product, the second wafer surface type product, the third wafer surface type product, and the fourth wafer surface type product respectively, to measure the imprinting thickness of the imprinting surface of the product and the relative position data between the lens and the diaphragm.

[0052] In the present invention, the refractive index of the imprinting surface of the first wafer surface type product and the imprinting surface of the fourth wafer surface type product is preferably 1.5. The refractive index of the imprinting surface of the second wafer surface type product and the imprinting surface of the third wafer surface type product is preferably 1.7.

[0053] After obtaining the first wafer surface type product, the second wafer surface type product, the third wafer surface type product, and the fourth wafer surface type product, the present invention bonds the imprinting surfaces of the first wafer surface type product, the second wafer surface type product, the third wafer surface type product, the fourth wafer surface type product, and the fifth wafer using a bonding glue to obtain a post-imprinting product.

[0054] In the present invention, the bonding preferably includes the following steps:

[0055] After the first wafer surface type product is painted with glue on the embossed surface, it is bonded with the second wafer surface type product in pairs and then cured to obtain a first bonding intermediate product. In the present invention, the glue painting is preferably carried out on a glue painting machine. In the present invention, the specific implementation of the glue painting preferably includes: placing the first wafer surface type product with the embossed surface facing up on the glue painting platform, turning on the vacuum adsorption after the alignment is OK (alignment), the glue painting diameter is preferably 349°, the radius is preferably 1.2mm, the coating gap is preferably 0.15mm, the air pressure is preferably 310kPa, and the glue type is preferably "C" shaped; in the present invention, the two-by-two bonding preferably adopts the two-by-two bonding procedure of the suss equipment, preferably the second wafer surface type product is adsorbed on the top with the embossed surface facing down, the Mark point on the first wafer surface type product is grasped in alignment, the product after the first wafer surface type product is painted with glue is adsorbed on the bottom to grasp the Mark point of the second wafer surface type product in alignment, and two-by-two embossing bonding is performed, and the obtained semi-finished product is cured to obtain the first bonding intermediate product. The curing is preferably UV curing, preferably carried out under ultraviolet light conditions. After the curing, the present invention preferably selects five points of the first bonding intermediate product, namely, the top, middle, bottom, left and right, to measure the thickness of the bonding layer and the relative position data of the lens structure of the first wafer surface type product and the lens structure of the second wafer surface type product.

[0056] After the embossing surface of the fourth wafer surface type product is painted with glue, it is bonded with the fifth wafer in pairs and then cured to obtain a second bonding intermediate product. In the present invention, the painting of glue is preferably carried out on a glue painting machine. In the present invention, the specific implementation of the painting of glue preferably includes: placing the embossing surface of the fourth wafer surface type product facing up on the painting glue platform, turning on vacuum adsorption after alignment is OK, the painting glue caliber is preferably 349°, the radius is preferably 1.2mm, the coating gap is preferably 0.15mm, the air pressure is preferably 310kPa, and the glue type is preferably "C" shaped; in the present invention, the pairwise bonding preferably adopts the pairwise bonding procedure of the suss equipment, preferably adsorbing the fifth wafer on it, adsorbing the product after the fourth wafer surface type product is painted with glue on the bottom to align and grab the Mark point of the fourth wafer surface type product, and performing pairwise embossing bonding, and the obtained semi-finished product is cured to obtain the second bonding intermediate product. The curing is preferably UV curing, preferably carried out under ultraviolet light conditions. In the present invention, the fifth wafer is a wafer-level optical glass (i.e., a glass wafer). After the curing, the present invention preferably selects five points of the second bonding intermediate product, namely, top, middle, bottom, left and right, to measure the thickness of the bonding layer thereof.

[0057] After the embossing surface of the third wafer surface type product is painted with glue, it is bonded with the other surface of the fourth wafer in the second bonding intermediate product in pairs and then cured to obtain the third bonding intermediate product. In the present invention, the glue painting is preferably carried out on a glue painting machine. In the present invention, the specific implementation of the glue painting preferably includes: placing the embossing surface of the third wafer surface type product facing up on the glue painting platform, turning on the vacuum adsorption after the alignment is OK, the glue painting diameter is preferably 349°, the radius is preferably 1.2mm, the coating gap is preferably 0.15mm, the air pressure is preferably 310kPa, and the glue type is preferably "C" shaped; in the present invention, the pairwise bonding preferably adopts the pairwise bonding procedure of the suss equipment, preferably adsorbing the other surface of the fourth wafer in the second bonding intermediate product downward on it, aligning and grabbing the Mark point of the second bonding intermediate product, adsorbing the product after the third wafer surface type product is painted with glue on it, aligning and grabbing the Mark point of the product after the third wafer surface type product is painted with glue, and performing pairwise embossing bonding, and the obtained semi-finished product is cured to obtain the third bonding intermediate product. The curing is preferably UV curing, preferably carried out under ultraviolet light conditions. After the curing, the present invention preferably selects five points of the third bonding intermediate product to measure the thickness of its bonding layer and the relative position data of the lens structure of the third wafer surface product and the lens structure of the second bonding intermediate product.

[0058] After the other surface of the second wafer in the first bonding intermediate product is painted with glue, it is bonded with the other surface of the third wafer in the third bonding intermediate product in pairs, and then cured and baked in sequence to obtain the stamped product. In the present invention, the glue painting is preferably carried out on a glue painting machine. In the present invention, the specific implementation of the glue painting preferably includes: placing the other surface of the second wafer in the first bonding intermediate product upward on the glue painting platform, turning on vacuum adsorption after the alignment is OK, the glue painting diameter is preferably 349°, the radius is preferably 1.2mm, the coating gap is preferably 0.15mm, the air pressure is preferably 310kPa, and the glue type is preferably "C" shaped; in the present invention, the two-by-two bonding preferably adopts the two-by-two bonding procedure of the suss equipment, preferably adsorbing the other surface of the third wafer in the third bonding intermediate product downward on it, aligning and grabbing the Mark point of the third bonding intermediate product, adsorbing the product after the first bonding intermediate product is painted with glue below, aligning and grabbing the Mark point of the first bonding intermediate product, and performing two-by-two stamping bonding, and the semi-finished product is successively cured and baked to obtain the stamped product. The curing is preferably UV curing, preferably carried out under ultraviolet light conditions. The baking temperature is preferably 120-150°C, and the time is preferably 1-2 hours. After the curing, the present invention preferably selects five points of the fourth bonding intermediate product to measure the thickness of its bonding layer and the relative position data of the lens structure of the first bonding intermediate product and the lens structure of the third bonding intermediate product, and then bakes the fourth bonding intermediate product to obtain the printed product.

[0059] After obtaining the stamped product, the present invention uses a cold plating method to plate a visible light cutoff film on the other surface of the fifth wafer in the stamped product to obtain a coated product, and the temperature of the cold plating is <30°C. In the present invention, the present invention preferably cleans the other surface of the fifth wafer in the stamped product. The cleaning is preferably performed using alcohol. In the present invention, the cold plating is preferably performed in a coating device. The result schematic diagram of the coating device used in the present invention is as shown in FIG. Figure 4 As shown, the present invention preferably arranges the other surface of the fifth wafer in the stamped product outward on the umbrella stand of the coating device.

[0060] In the present invention, the evaporation source of the cold plating preferably includes Ti 3 O 5 and SiO 2 ; the Ti 3 O 5 The evaporation rate is preferably The SiO 2 The evaporation rate is preferably During the cold plating process, the substrate is not heated, and the cold plating time is preferably 6-7 h. In the present invention, the temperature in the cavity is preferably monitored to be <30 °C during the cold plating process. After the cold plating is completed, the present invention preferably tests the transmittance of the accompanying plating sheet, and obtains the transmittance data of the visible light cutoff film from the transmittance data of the accompanying plating sheet. In the present invention, the transmittance data of the visible light cutoff film is preferably OD2 at 420-790 nm; Tave > 92% at 820-970 nm.

[0061] After obtaining the product after coating, the present invention performs post-treatment on the product after coating to obtain the optical module. In the present invention, the post-treatment of the coating preferably includes cutting, mirror base attachment (HA), and spraying in sequence. In the present invention, the specific implementation manner of the cutting preferably includes: pasting the side of the fifth wafer with the visible light cutoff film of the product after coating on the blue film, selecting the cutting tool model according to the product thickness, manually aligning the cutting position, setting the number of cutting tools, and cutting along the edge of the photolithography frame of the photoresist pattern of the first wafer. After cutting, the UV blue film is removed to obtain 25 lens products. In the present invention, the specific implementation manner of the HA preferably includes: cleaning the side of the fifth wafer and the chip COMS surface of the lens product respectively, pasting the cleaned lens product on the high-temperature tape carrier for lens feeding, setting the production quantity and lens positioning, dispensing glue on the chip COMS surface, and the device grabs the edge of the side of the fifth wafer of the lens product and attaches it to the chip, and then performs UV curing. After checking the appearance of the module, baking is carried out. The temperature of the baking is preferably 120-150 °C, and the time is preferably 1-2 h.

[0062] In the present invention, after the baking step of the HA treatment is completed, the obtained product is sprayed. In the present invention, the ink composition used for spraying preferably includes ink, curing agent, diluent, and additive. In the present invention, the ink is preferably HF-PYB 2309-2075C special black for spraying (Dongguan Aipuluo Technology Co., Ltd.), the curing agent is preferably D hardener (Dongguan Aipuluo Technology Co., Ltd.), the diluent is preferably YC0371 diluent (Dongguan Aipuluo Technology Co., Ltd.), and the additive is preferably CARE73N additive (Dongguan Aipuluo Technology Co., Ltd.). The mass ratio of the ink, the curing agent, the diluent, and the additive in the ink composition is preferably 10:1:8:0.3. Before spraying, the present invention preferably applies foam to the top and bottom of the product obtained by HA treatment, and then pastes it on a large board. The distance between the product obtained by HA treatment and the nozzle is preferably 7-10 cm, the spraying speed is preferably 40-45 mm / s, the number of spraying times is preferably four times, and it is turned over every two times. After each spraying, pre-curing and baking are carried out in sequence. The temperature of the pre-curing is preferably 120 °C and the time is preferably 15 min. The temperature of the baking is preferably 120-150 °C and the time is preferably 40 min.

[0063] The present invention provides an optical module prepared by the preparation method described in the above technical solution, which includes a first wafer, a first residual imprinting glue layer, a first bonding layer, a second residual imprinting glue layer, a second wafer, a second bonding layer, a third wafer, a third residual imprinting glue layer, a third bonding layer, a fourth wafer, a fourth residual imprinting glue layer, a fourth bonding layer, a fifth wafer, and a visible light cutoff layer stacked in sequence.

[0064] In the present invention, in the optical module: the thickness of the first wafer is preferably 400 μm. The thickness of the first residual imprinting glue layer is preferably 461.1 μm. The thickness of the first bonding layer is preferably 30 μm. The thickness of the second residual imprinting glue layer is preferably 139.6 μm. The thickness of the second wafer is preferably 500 μm. The thickness of the second bonding layer is preferably 30 μm. The thickness of the third wafer is preferably 300 μm. The thickness of the third residual imprinting glue layer is preferably 263 μm. The thickness of the third bonding layer is preferably 30 μm. The thickness of the fourth wafer is preferably 400 μm. The thickness of the fourth residual imprinting glue layer is preferably 467 μm. The thickness of the fourth bonding layer is preferably 30 μm. The thickness of the fifth wafer is preferably 850 μm.

[0065] The present invention has no special requirements for the thickness of the visible light cutoff layer, as long as the performance requirements of the optical module are met. The transmittance data of the visible light cutoff film is preferably OD2 at 420-790 nm; Tave>92% at 820-970 nm.

[0066] The optical module for micro eye tracking and iris recognition prepared by nanoimprint technology and cold plating process provided by the present invention has a pixel size of 1.4μm×1.4μm, a pixel array of 1000×1000, a frame rate of 80FPS, and a maximum FOV of 120° in the high frame rate mode, meeting the requirements of low power consumption and miniaturization of the module on the VR / AR whole machine; the nanoimprint technology has low cost, high efficiency, and good consistency.

[0067] The present invention provides an application of the optical module described in the above technical solution in a micro eye tracking and / or iris recognition module.

[0068] In order to further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below in conjunction with embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0069] Embodiment 1

[0070] Process steps of imprinting first and then coating:

[0071] (1) Preparation of materials in the early stage

[0072] Mold preparation: The molds prepared in this embodiment are four surface molds, namely S1 mold, S2 mold, S3 mold, and S4 mold, and the four surface molds form a module. In this embodiment, the four surface molds are processed by turning process, and the preparation method of the four surface molds includes: processing a lens structure on a metal substrate with a nickel plating layer on the surface to prepare four metal molds with different surface shapes, and there are 25 lens patterns on each mold.

[0073] Stamp preparation: The stamps prepared in this embodiment are respectively transfer templates with the reverse pattern of the S1 mold structure (i.e., S1 mold stamp), transfer templates with the reverse pattern of the S2 mold structure (i.e., S2 mold stamp), transfer templates with the reverse pattern of the S3 mold structure (i.e., S3 mold stamp), and transfer templates with the reverse pattern of the S4 mold structure (i.e., S4 mold stamp).

[0074] Among them, the preparation method of the S1 mold stamp includes: first, plasma clean the surface of the quartz glass, prepare a polydimethylsiloxane imprinting glue, evenly pour a layer of imprinting glue in the center of the side with the preset structural pattern of the S1 mold, drain the glue from the center point of the quartz glass, and use a SUSS imprinting device (SUSS Micro Tec) for imprinting to transfer the preset nano-structural pattern on the metal mold to the soft template, obtaining a transfer template with the reverse pattern of the S1 mold structure, that is, the S1 mold stamp.

[0075] The preparation methods of the S2 mold stamp, S3 mold stamp, and S4 mold stamp are basically the same as the preparation method of the S1 mold stamp, except that the S2 mold, S3 mold, and S4 mold are used respectively.

[0076] Lithography of glass wafers: Clean the glass wafers, coat the upper surface of the glass wafers with photoresist, and through exposure and development, make the apertures on the corresponding mask plate on the wafer glass to obtain S1 glass wafers and S3 glass wafers.

[0077] The array arrangement pitch of the lithography pattern of the S1 glass wafer product is the same as the arrangement of the S1 mold. The light leakage area of the S1 glass wafer is an equal-length and equal-width rectangular area of a single lens, and the light-shielding area of the S1 glass wafer is the cutting area between a single lens and a single lens.

[0078] In this embodiment, the mold preparation, sub-mold (stamp) preparation, and lithography process of the glass wafer are as Figure 1 shown.

[0079] (2) Imprinting process

[0080] Single-sided imprinting: Use a SUSS imprinting device (SUSS Micro Tec) to vacuum adsorb the stamp imprinting mold (MasterStamp) and the glass wafers (including S1 glass wafers, S3 glass wafers, and two blank glass wafers, where the blank glass wafers are glass wafers without lithography patterns) at the upper and lower positions of the imprinting machine, pour imprinting glue at the middle position of the glass wafers, and transfer the reverse pattern of the structure on the stamp to the upper surface of the imprinting glue layer of the wafer glass to obtain a single side with a lens structure on the upper surface of the imprinting glue layer. A total of 4 imprinted single sides are obtained on the four wafer glasses, namely, S1 surface type, S2 surface type, S3 surface type, and S4 surface type. Five points in the upper, middle, lower, left, and right positions are respectively selected for the S1 surface type, S2 surface type, S3 surface type, and S4 surface type to measure the thickness of the residual layer glue (imprinting surface) and the relative position data of the lens and the aperture. The refractive index of the residual layer glue (imprinting surface) of the S1 surface type and the S4 surface type is 1.5, and the refractive index of the residual layer glue (imprinting surface) of the S2 surface type and the S3 surface type is 1.7.

[0081] Bonding in pairs: The method of bonding the S1+S2 surface types specifically includes: Using a glue painting machine, place the imprinting surface of the S1 surface type face up on the glue painting platform. After correct alignment, turn on the vacuum adsorption. The glue painting aperture is 349°, the radius is 1.2 mm, the coating gap is 0.15 mm, the air pressure is 310 kPa, and the glue type is in a "C" shape. Use a SUSS imprinting device (SUSS Micro Tec), select the bonding-in-pairs program, adsorb the imprinting surface of the S2 surface type on it, grab the Mark point of the S1 surface type for alignment, adsorb the product after glue painting of the S1 surface type below, grab the Mark point of the S2 surface type for alignment, and perform S1+S2 imprinting bonding. After UV curing with an ultraviolet lamp, obtain the bonded product of the S1+S2 surface type, and select five points in the upper, middle, lower, left, and right positions to measure the bonding layer thickness and the relative position data of the lens and the lens of the bonded product of the S1+S2 surface type.

[0082] The method for S4+S5 surface type bonding specifically includes: using a glue painting machine, placing the imprinted surface of the S4 surface type face up on the glue painting platform. After correct alignment, turn on the vacuum adsorption. The glue painting aperture is 349°, the radius is 1.2 mm, the coating gap is 0.15 mm, the air pressure is 310 kPa, and the glue type is in a "C" shape. Using a SUSS imprinting device (SUSS Micro Tec), select the pairwise bonding program. The imprinted surface of the S5 surface type (i.e., blank glass wafer) is adsorbed on it, and the product after glue painting of the S4 surface type is adsorbed below. Grab the Mark point of the S4 surface type for alignment, perform S4+S5 imprinting bonding. After UV curing with an ultraviolet lamp, obtain the S4+S5 surface type bonded product. Select five points of top, middle, bottom, left, and right to measure the bonding layer thickness of the S4+S5 surface type bonded product.

[0083] The method for S3+S4+S5 surface type bonding specifically includes: using a glue painting machine, placing the imprinted surface of the S3 surface type face up on the glue painting platform. After correct alignment, turn on the vacuum adsorption. The glue painting aperture is 349°, the radius is 1.2 mm, the coating gap is 0.15 mm, the air pressure is 310 kPa, and the glue type is in a "C" shape. Using a SUSS imprinting device (SUSS Micro Tec), select the pairwise bonding program. The imprinted surface of the S4+S5 surface type bonded product is adsorbed on it. Grab the Mark point of the S4+S5 surface type bonded product for alignment. The product after glue painting of the S3 surface type is adsorbed below. Grab the Mark point of the product after glue painting of the S3 surface type for alignment, perform S3+S4+S5 imprinting bonding. After UV curing with an ultraviolet lamp, obtain the S3+S4+S5 surface type bonded product. Select five points of top, middle, bottom, left, and right to measure the bonding layer thickness of the S3+S4+S5 surface type bonded product and the relative position data of lens to lens.

[0084] The method of S1+S2+S3+S4+S5 surface bonding specifically includes: using a glue painting machine, placing the imprinted surface of the S1+S2 surface bonding product face up on the glue painting platform, turning on the vacuum adsorption after correct alignment, with a glue painting aperture of 349°, a radius of 1.2 mm, a coating gap of 0.15 mm, an air pressure of 310 kPa, and the glue type being "C" shaped. Using a SUSS imprinting device (SUSS Micro Tec), select the pairwise bonding program, adsorb the imprinted surface of the S3+S4+S5 surface bonding product on it, align and grab the Mark point of the S3+S4+S5 surface bonding product, adsorb the product after glue painting of the S1+S2 surface bonding product below, align and grab the Mark point of the product after glue painting of the S1+S2 surface bonding product, perform S1+S2+S3+S4+S5 imprinting bonding, after UV curing with an ultraviolet lamp, obtain the S1+S2+S3+S4+S5 surface bonding product, select five points of top, middle, bottom, left, and right to measure the bonding layer thickness of the S1+S2+S3+S4+S5 surface bonding product and the relative position data of the lens structure of the first bonding intermediate product and the lens structure of the third bonding intermediate product. After the imprinting is completed, bake the S1+S2+S3+S4+S5 surface bonding product to obtain the imprinted product, with a baking temperature of 120 °C and a baking time of 2 h.

[0085] The imprinting process flow in this embodiment is as Figure 2 shown.

[0086] (3) Coating process flow:

[0087] Coating: Clean the S5 surface of the imprinted product with alcohol, place it on the umbrella rack, coating materials: Ti 3 O 5 , SiO 2 , the evaporation rate of Ti 3 O 5 is The evaporation rate of SiO 2 is The substrate is not heated, monitor the temperature in the cavity < 30 °C during the process, for 7 h. After the cold coating is completed, test the transmittance of the accompanying coating piece to be 420 - 790 nm OD 2 ; 820 - 970 nm Tave > 92%. After the cold coating is completed, obtain the coated product.

[0088] The coating process flow in this embodiment is as Figure 3 shown.

[0089] The schematic diagram of the coating device in this embodiment is as Figure 4 shown.

[0090] (4) Process flow after coating

[0091] Cutting: Paste the S5 surface of the coated product onto the blue film. Select the cutting tool model according to the product thickness, manually align the cutting position, set the number of cutting passes, and cut along the edge of the lithography frame on the S1 surface of the coated product. After cutting, release the UV blue film to obtain 25 lens products.

[0092] The structural schematic diagram of the lens product prepared in this embodiment is as Figure 6 shown ( Figure 6 only used to represent the schematic diagram of the layer structure of the lens product and cannot represent the true thickness of each layer in the structure).

[0093] HA: Clean the S5 surface of the lens product and the chip COMS surface, and paste the cleaned lens product on the high-temperature tape carrier; load the lens, set the production quantity, position the lens, apply glue at the chip COMS surface, the equipment grabs the edge of the S5 surface of the lens product and attaches it to the chip, cure with UV, and bake at 120 °C for 1 h after inspecting the appearance of the module to obtain the module product.

[0094] Spraying: Configure the ink (HF-PYB 2309-2075C special black for spraying, Dongguan Aipuluo Technology Co., Ltd.), curing agent (D hardener, Dongguan Aipuluo Technology Co., Ltd.), diluent (YC0371 diluent, Dongguan Aipuluo Technology Co., Ltd.), and additive (CARE73N additive, Dongguan Aipuluo Technology Co., Ltd.) in a certain proportion. The mass ratio of the ink, curing agent, diluent, and additive is 10:1:8:0.3. Paste foam on the top and bottom of the module product, paste it on the large board, keep a distance of 7 - 10 cm between the module product and the nozzle, the spraying speed is 42.5 ± 2.5 mm / s, spray four times, turn it over every two times, and perform pre-curing (pre-curing temperature is 120 °C, time is 15 min) and baking (baking temperature is 120 °C, time is 40 min) in sequence after each spraying to obtain the eye movement tracking optical module (optical element).

[0095] The technological process after coating in this embodiment is as Figure 5 shown.

[0096] In this embodiment, the micro eye movement tracking and iris recognition module prepared by nanoimprint technology and cold plating process has a pixel size of 1.4 μm × 1.4 μm, a pixel array of 1000 × 1000, a frame rate of 80 FPS, and a maximum FOV of 120° in the high frame rate mode, meeting the requirements of low power consumption and miniaturization of the module on the VR / AR whole machine; the nanoimprint technology has low cost, high efficiency, and good consistency.

[0097] As can be seen from the above embodiments, the preparation method provided by the present invention adopts nanoimprint technology combined with cold plating process, first imprints and then coats the film. The single-sided surface type is imprinted on the surface of the wafer-level optical glass using glue, and each surface type is stacked using bonding glue, and then the visible light cut-off film is coated on the surface of the product using the cold plating process. The preparation method provided by the present invention effectively avoids the change of the lens surface type due to heat during the film coating process, and solves problems such as warping of the glass after imprinting and then coating, inability to measure the imprint alignment, and difficulty in grasping the edge during cutting. The optical module for shared use of micro eye movement tracking and iris recognition prepared by the present invention has the advantages of small size, low cost, high production efficiency, and good performance consistency.

[0098] Although the above embodiments have made a detailed description of the present invention, they are only a part of the embodiments of the present invention, rather than all embodiments. Other embodiments can be obtained based on these embodiments without creative efforts, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing an optical module, characterized in that: The following steps are involved: preparing a sub-mold by a metal mold, the metal mold comprising a first metal mold, a second metal mold, a third metal mold and a fourth metal mold, the first metal mold, the second metal mold, the third metal mold and the fourth metal mold having lens structure patterns of different shapes, the sub-mold comprising a first sub-mold having a pattern opposite to that of the first metal mold, a second sub-mold having a pattern opposite to that of the second metal mold, a third sub-mold having a pattern opposite to that of the third metal mold and a fourth sub-mold having a pattern opposite to that of the fourth metal mold; Imprint glue is arranged on one surface of the first wafer, the second wafer, the third wafer and the fourth wafer, and the first sub-mold, the second sub-mold, the third sub-mold and the fourth sub-mold are used for imprinting respectively, so as to obtain the first wafer surface type product, the second wafer surface type product, the third wafer surface type product and the fourth wafer surface type product respectively; the other surfaces of the first wafer and the third wafer have photoresist patterns, the photoresist patterns on the other surface of the first wafer have the same arrangement pitch as the pattern array of the first sub-mold, and the photoresist patterns on the other surface of the third wafer have the same arrangement pitch as the pattern array of the third sub-mold; Bonding the stamped surface of the first wafer surface type product, the stamped surface of the second wafer surface type product, the stamped surface of the third wafer surface type product, the stamped surface of the fourth wafer surface type product and the fifth wafer using bonding adhesive to obtain a stamped product; A visible light cutoff film is plated on the other surface of the fifth wafer in the stamped product by a cold plating method to obtain a film-coated product, wherein the cold plating temperature is less than 30° C.; The coated product is subjected to post-coating treatment to obtain the optical module.

2. The preparation method according to claim 1, characterized in that: Each of the metal molds has 25 lens structure patterns.

3. The preparation method according to claim 1 or 2, characterized in that: The light leakage area in the photoresist pattern on the other surface of the first wafer is a rectangular area with the same length and width as the single lens on the first sub-mold; the light shielding area in the photoresist pattern on the other surface of the first wafer corresponds to the cutting area between the single lenses on the first sub-mold; The light leakage area in the photoresist pattern on the other surface of the third wafer is a rectangular area with the same length and width as the single lens on the third sub-mold; the light shielding area in the photoresist pattern on the other surface of the third wafer corresponds to the cutting area between the single lenses on the third sub-mold.

4. The preparation method according to claim 1, characterized in that: The refractive index of the stamping surface of the first wafer surface type product and the stamping surface of the fourth wafer surface type product is 1.5; The refractive index of the stamping surface of the second wafer face type product and the stamping surface of the third wafer face type product is 1.

7.

5. The preparation method according to claim 1, characterized in that: The bonding comprises the following steps: Applying glue to the embossed surface of the first wafer surface type product and bonding them with the embossed surface of the second wafer surface type product in pairs and then curing them to obtain a first bonding intermediate product; The embossed surface of the fourth wafer surface type product is bonded with the fifth wafer in pairs and then cured to obtain a second bonding intermediate product; Bonding the embossed surface of the third wafer surface-shaped product with the other surface of the fourth wafer in the second bonding intermediate product in pairs and then curing them to obtain a third bonding intermediate product; The other surface of the second wafer in the first bonding intermediate product is coated with glue, and then bonded with the other surface of the third wafer in the third bonding intermediate product in pairs, and then cured and baked in sequence to obtain the printed product.

6. The preparation method according to claim 1, characterized in that: The method for preparing the sub-mold comprises the following steps: An embossing glue is arranged on the side of the metal mold with the lens structure pattern, and a drainage glue is added to the center point of the quartz glass, and then embossing is performed to obtain a sub-mold with a pattern opposite to that of the metal mold; the sub-mold includes quartz glass and a soft template arranged on the surface of the quartz glass, and the soft template has a pattern opposite to that of the metal mold.

7. The preparation method according to claim 6, characterized in that: The embossing glue is polydimethylsiloxane embossing glue.

8. The preparation method according to claim 1, characterized in that: The cold plating evaporation source includes Ti3O5 and SiO2; the evaporation rate of Ti3O5 is The evaporation rate of SiO2 The substrate is not heated during the cold plating process, and the cold plating time is 6 to 7 hours.

9. The optical module prepared by the preparation method according to any one of claims 1 to 8, characterized in that: It includes a first wafer, a first embossed adhesive residual layer, a first bonding layer, a second embossed adhesive residual layer, a second wafer, a second bonding layer, a third wafer, a third embossed adhesive residual layer, a third bonding layer, a fourth wafer, a fourth embossed adhesive residual layer, a fourth bonding layer, a fifth wafer and a visible light cutoff layer which are stacked in sequence.

10. Application of the optical module according to claim 9 in a micro eye tracking and / or iris recognition module.

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