An optical module, its fabrication method and application

Abstract

The application belongs to the technical field of eye movement tracking, and particularly relates to an optical module, a preparation method and application thereof. The preparation method provided by the application adopts a nano-imprinting technology combined with a cold plating process, performs imprinting first and then plating, uses glue to imprint a single-face shape on a wafer-level optical glass surface, finally stacks each shape using bonding glue, and then adopts a cold plating process to plate a visible light cutoff film on the surface of the product. The preparation method provided by the application effectively avoids the change of the lens shape caused by the glue heated in the plating process, solves the problems of glass warping after imprinting and plating first, and cutting and grabbing edges, and the like. The optical module prepared by the application has the advantages of small size, low cost, high production efficiency, and good performance consistency.

Description

Technical Field

[0001] This invention belongs to the field of eye-tracking technology, specifically relating to an optical module, its preparation method, and its application. Background Technology

[0002] Eye-tracking modules are specialized technology modules used to acquire the gaze position and attention of human eyes. They have advantages such as high precision, low latency, and ease of integration and application, and have broad application prospects in VR / AR, advertising and marketing, and healthcare.

[0003] Currently, most eye-tracking modules suffer from high production costs and poor performance consistency. Summary of the Invention

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

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] This invention provides a method for fabricating an optical module, comprising the following steps:

[0007] Sub-molds are prepared 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 of different shapes, 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;

[0008] Imprinting adhesive is applied to one surface of a first wafer, a second wafer, a third wafer, and a fourth wafer. Imprinting is performed using a first sub-mold, a second sub-mold, a third sub-mold, and a fourth sub-mold, respectively, to obtain a first wafer surface product, a second wafer surface product, a third wafer surface product, and a fourth wafer surface product, respectively. The other surface of the first wafer and the third wafer has a photoresist pattern. The spacing of the photoresist pattern on the other surface of the first wafer is the same as that of the pattern array of the first sub-mold. The spacing of the photoresist pattern on the other surface of the third wafer is the same as that of the pattern array of the third sub-mold.

[0009] The imprinted surfaces of the first wafer type product, the second wafer type product, the third wafer type product, the fourth wafer type product, and the fifth wafer are bonded together with bonding adhesive to obtain the imprinted product.

[0010] A visible light cutoff film is deposited on the other surface of the fifth wafer in the imprinted product using a cold plating method to obtain the coated product. The temperature of the cold plating is <30°C.

[0011] The coated product undergoes post-coating processing to obtain the optical module.

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

[0013] Preferably, the light-leaking 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 the single lens and the single lens on the first sub-mold.

[0014] The light-leaking 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 lens and the single lens on the third sub-mold.

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

[0016] The refractive index of the imprinted surface of the second wafer type product and the imprinted surface of the third wafer type product is 1.7.

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

[0018] After applying adhesive to the imprinted surface of the first wafer-type product, it is bonded to the imprinted surface of the second wafer-type product in pairs and then cured to obtain the first bonded intermediate product.

[0019] After applying adhesive to the imprinted surface of the fourth wafer-shaped product, it is bonded to the fifth wafer in pairs and then cured to obtain the second bonded intermediate product.

[0020] After applying adhesive to the imprinted surface of the third wafer-shaped product, it is bonded to 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.

[0021] After applying adhesive to the other surface of the second wafer in the first bonding intermediate product, the wafer is bonded to the other surface of the third wafer in the third bonding intermediate product in pairs, and then cured and baked sequentially to obtain the imprinted product.

[0022] Preferably, the method for preparing the sub-mold includes the following steps:

[0023] Imprinting adhesive is applied to one side of the metal mold with the lens structure pattern, and drainage adhesive is added to the center point of the quartz glass. Imprinting is then 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 disposed on the surface of the quartz glass, the soft template having a pattern opposite to that of the metal mold.

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

[0025] Preferably, the evaporation source for the cold plating includes Ti3O5 and SiO2; the evaporation rate of Ti3O5 is... The evaporation rate of the SiO2 The substrate is not heated during the cold plating process, and the cold plating time is 6 to 7 hours.

[0026] The present invention provides an optical module prepared by the preparation method described above, comprising a first wafer, a first imprinting adhesive residue layer, a first bonding layer, a second imprinting adhesive residue layer, a second wafer, a second bonding layer, a third wafer, a third imprinting adhesive residue layer, a third bonding layer, a fourth wafer, a fourth imprinting adhesive residue layer, a fourth bonding layer, a fifth wafer, and a visible light cutoff layer, which are stacked sequentially.

[0027] This invention provides the application of the optical module described above in a miniature eye-tracking and / or iris recognition module.

[0028] This invention provides a method for fabricating an optical module. The method employs nanoimprint lithography combined with a cold deposition process. Imprinting is performed first, followed by deposition. A single-sided surface is imprinted onto the surface of a wafer-level optical glass using adhesive. These surfaces are then stacked using bonding adhesive. Finally, a visible light cutoff film is deposited onto the product surface using a cold deposition process. This method effectively avoids the adhesive from altering the lens surface shape due to heat during deposition, and solves problems such as glass warping after imprinting and deposition, difficulty in measuring imprint alignment, and difficulty in edge cutting. The resulting miniature optical module, which combines eye tracking and iris recognition, has advantages such as small size, low cost, high production efficiency, and good performance consistency.

[0029] Furthermore, in this invention, the refractive index of the imprinted surfaces of the first and fourth wafer-type products is 1.5; the refractive index of the imprinted surfaces of the second and third wafer-type products is 1.7. This invention uses a high-transmittance imprinting adhesive for single-sided imprinting, which is more conducive to alignment and thickness measurement during the nanoimprinting process, resulting in an optical module with good performance consistency. Attached Figure Description

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

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

[0032] Figure 3 This is a flow chart of the coating process in Embodiment 1 of the present invention;

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

[0034] Figure 5 This is a process flow diagram of the coating process in Embodiment 1 of the present invention;

[0035] Figure 6 This is a schematic diagram of the lens product structure prepared in Example 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 evaporating material, 6 is the evaporation source, 7 is the film thickness gauge, 8 is the first wafer, 9 is the first imprinting adhesive residue layer, 10 is the first bonding layer, 11 is the second imprinting adhesive residue layer, 12 is the second wafer, 13 is the second bonding layer, 14 is the third wafer, 15 is the third imprinting adhesive residue layer, 16 is the third bonding layer, 17 is the fourth wafer, 18 is the fourth imprinting adhesive residue layer, 19 is the fourth bonding layer, 20 is the fifth wafer, and 21 is the visible light cutoff film. Detailed Implementation

[0037] This invention provides a method for fabricating an optical module, comprising the following steps:

[0038] Sub-molds are prepared 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 of different shapes, 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] Imprinting adhesive is applied to one surface of a first wafer, a second wafer, a third wafer, and a fourth wafer. Imprinting is performed using a first sub-mold, a second sub-mold, a third sub-mold, and a fourth sub-mold, respectively, to obtain a first wafer surface product, a second wafer surface product, a third wafer surface product, and a fourth wafer surface product, respectively. The other surface of the first wafer and the third wafer has a photoresist pattern. The spacing of the photoresist pattern on the other surface of the first wafer is the same as the spacing of the pattern array of the first sub-mold. The spacing of the photoresist pattern on the other surface of the third wafer is the same as the spacing of the pattern array of the third sub-mold.

[0040] The imprinted surfaces of the first wafer type product, the second wafer type product, the third wafer type product, the fourth wafer type product, and the fifth wafer are bonded together with bonding adhesive to obtain the imprinted product.

[0041] A visible light cutoff film is deposited on the other surface of the fifth wafer in the imprinted product using a cold plating method to obtain the coated product. The temperature of the cold plating is <30°C.

[0042] The coated product undergoes post-coating processing to obtain the optical module.

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

[0044] This invention relates to the fabrication of sub-molds using metal molds. The metal molds include a first metal mold, a second metal mold, a third metal mold, and a fourth metal mold. These metal molds have lens structure patterns of different shapes. Each sub-mold includes a first sub-mold with a pattern opposite to that of the first metal mold, a second sub-mold with a pattern opposite to that of the second metal mold, a third sub-mold with a pattern opposite to that of the third metal mold, and a fourth sub-mold with a pattern opposite to that of the fourth metal mold. Preferably, the fabrication method of the metal molds includes turning a metal substrate with a nickel-plated surface to obtain the metal molds. Each metal mold has 25 lens structure patterns. The lens structures on the metal molds are arranged in an array. The first, second, third, and fourth metal molds are metal molds with four different surface shapes.

[0045] In this invention, the method for preparing the sub-mold preferably includes the following steps:

[0046] Imprinting adhesive is applied to one side of a metal mold with a lens structure pattern, and a draining adhesive is added to the center point of a quartz glass. Imprinting is then 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 disposed on the surface of the quartz glass, the soft template having a pattern opposite to that of the metal mold. Preferably, the quartz glass is pretreated, specifically by plasma cleaning of the quartz glass surface. The specific implementation process of the plasma cleaning is not particularly important. The application of the imprinting adhesive is preferably done by pouring a layer of imprinting adhesive onto the center position of the side of the metal mold with the lens structure pattern. The imprinting adhesive is polydimethylsiloxane imprinting adhesive. The imprinting is performed using an imprinting device, which can be a SUSS imprinting device. Preferably, the present invention transfers the pre-set nanostructure pattern on the metal mold to the soft template through imprinting, obtaining a transfer template, i.e., a sub-mold, with a reversed structural pattern. The soft template is the imprinting adhesive template.

[0047] After obtaining the sub-mold, the present invention applies imprinting adhesive to one surface of the first wafer, the second wafer, the third wafer, and the fourth wafer, and performs imprinting using the first sub-mold, the second sub-mold, the third sub-mold, and the fourth sub-mold, respectively, to obtain the first wafer surface product, the second wafer surface product, the third wafer surface product, and the fourth wafer surface product, respectively. The other surface of the first wafer and the third wafer has a photoresist pattern, with the photoresist pattern on the other surface of the first wafer having the same spacing as the pattern array arrangement of the first sub-mold, and the photoresist pattern on the other surface of the third wafer having the same spacing as the pattern array arrangement of the third sub-mold. In the present invention, the light-leaking 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 the single lenses on the first sub-mold. The light-leaking 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 lens on the third sub-mold.

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

[0049] In this invention, the fabrication method of the first and third wafers preferably includes the following steps: coating a photoresist onto another surface of the first or third wafer, and then obtaining a photoresist pattern through exposure and development. Before coating the photoresist, the first or third wafer is preferably cleaned. This invention does not have specific requirements for the specific implementation of the exposure and development steps.

[0050] In this invention, the first, second, third, and fourth wafer-type products are preferably manufactured using a single-sided imprinting method. The single-sided imprinting is preferably performed using an imprinting device, which can be a SUSS imprinting device. A preferred embodiment of the single-sided imprinting in this invention includes: vacuum-adsorbing the first, second, third, or fourth wafers and their corresponding sub-molds onto the lower and upper positions of an imprinting machine; applying imprinting adhesive to the middle of one surface of the first, second, third, or fourth wafer; setting the offset, GAP value, and imprinting speed according to the residual layer thickness of the structural design; and copying the reverse pattern of the structure on the stamp to the upper surface of the imprinting adhesive layer on the first, second, third, or fourth wafer (wafer glass), resulting in a single-sided imprinting adhesive layer with a lens structure on its upper surface, thus obtaining the first, second, third, and fourth wafer-type products.

[0051] After obtaining the first wafer surface product, the second wafer surface product, the third wafer surface product, and the fourth wafer surface product, the present invention preferably selects five points (top, middle, bottom, left, and right) on the first wafer surface product, the second wafer surface product, the third wafer surface product, and the fourth wafer surface product to measure the imprint thickness of the imprint surface and the relative position data of the lens and the aperture.

[0052] In this invention, the refractive index of the imprinted surfaces of the first wafer-type product and the fourth wafer-type product is preferably 1.5. The refractive index of the imprinted surfaces of the second wafer-type product and the third wafer-type product is preferably 1.7.

[0053] After obtaining the first wafer surface product, the second wafer surface product, the third wafer surface product, and the fourth wafer surface product, the present invention uses bonding adhesive to bond the imprinted surface of the first wafer surface product, the imprinted surface of the second wafer surface product, the imprinted surface of the third wafer surface product, the imprinted surface of the fourth wafer surface product, and the fifth wafer to obtain the imprinted product.

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

[0055] After applying adhesive to the imprinted surface of the first wafer-type product, it is bonded to the imprinted surface of the second wafer-type product in pairs and then cured to obtain a first bonded intermediate product. In this invention, the adhesive application is preferably performed on an adhesive application machine. The specific implementation of the adhesive application preferably includes: placing the imprinted surface of the first wafer-type product upwards on an adhesive application platform, aligning it, and then opening vacuum adsorption. The adhesive application nozzle diameter is preferably 349°, the radius is preferably 1.2 mm, the coating gap is preferably 0.15 mm, the air pressure is preferably 310 kPa, and the adhesive form is preferably "C" shaped. In this invention, the pairwise bonding preferably uses a pairwise bonding program of a Suss device. Preferably, the imprinted surface of the second wafer-type product is adsorbed downwards on top, and the Mark points on the first wafer-type product are aligned and captured. The product with adhesive applied to the first wafer-type product is adsorbed downwards, and the Mark points on the second wafer-type product are aligned and captured. Pairwise imprinting and bonding are performed, and the resulting semi-finished product is cured to obtain the first bonded intermediate product. The curing is preferably UV curing, and more preferably carried out under ultraviolet light. After curing, the present invention preferably selects five points (top, middle, bottom, left, and right) of the obtained first bonding intermediate product to measure the thickness of its bonding layer and the relative position data of the lens structure of the first wafer surface product and the lens structure of the second wafer surface product.

[0056] After applying adhesive to the imprinted surface of the fourth wafer-type product, it is bonded to the fifth wafer in pairs and then cured to obtain a second bonded intermediate product. In this invention, the adhesive application is preferably performed on an adhesive application machine. A preferred embodiment of the adhesive application includes: placing the imprinted surface of the fourth wafer-type product upwards on an adhesive application platform, aligning it, and then opening vacuum adsorption. The adhesive application aperture is preferably 349°, the radius is preferably 1.2 mm, the coating gap is preferably 0.15 mm, the air pressure is preferably 310 kPa, and the adhesive form is preferably "C" shaped. In this invention, the pairwise bonding preferably uses a Suss bonding program. Preferably, the fifth wafer is adsorbed on the platform, and the fourth wafer-type product, after adhesive application, is adsorbed below, aligning and capturing the mark points of the fourth wafer-type product for pairwise imprint bonding. The resulting semi-finished product is then cured to obtain the second bonded intermediate product. The curing is preferably UV curing, preferably performed under ultraviolet light conditions. In this invention, the fifth wafer is wafer-grade optical glass (i.e., a glass wafer). After curing, the present invention preferably measures the thickness of the bonding layer at five points (top, middle, bottom, left, and right) of the second bonding intermediate product.

[0057] After applying adhesive to the imprinted surface of the third wafer-shaped product, it is bonded pairwise to the other surface of the fourth wafer in the second bonding intermediate product, and then cured to obtain the third bonding intermediate product. In this invention, the adhesive application is preferably performed on an adhesive application machine. A preferred embodiment of the adhesive application includes: placing the imprinted surface of the third wafer-shaped product upwards on an adhesive application platform, aligning it, and then opening vacuum adsorption. The adhesive application nozzle diameter is preferably 349°, the radius is preferably 1.2 mm, the coating gap is preferably 0.15 mm, the air pressure is preferably 310 kPa, and the adhesive form is preferably "C" shaped. In this invention, the pairwise bonding preferably uses a Suss bonding program. Preferably, the other surface of the fourth wafer in the second bonding intermediate product is adsorbed downwards on the platform, the Mark points of the second bonding intermediate product are aligned and captured, the adhesive-coated product of the third wafer-shaped product is adsorbed downwards, the Mark points of the adhesive-coated product of the third wafer-shaped product are aligned and captured, and pairwise imprint bonding is performed. The resulting semi-finished product is then cured to obtain the third bonding intermediate product. The curing is preferably UV curing, and more preferably carried out under ultraviolet light. After curing, the present invention preferably selects five points (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 third wafer surface product and the lens structure of the second bonding intermediate product.

[0058] The second wafer in the first bonding intermediate product is coated with adhesive and then bonded to the other surface of the third wafer in the third bonding intermediate product in pairs. The two wafers are then cured and baked sequentially to obtain the imprinted product. In this invention, the adhesive coating is preferably performed on an adhesive coating machine. A preferred embodiment of the adhesive coating process includes: placing the second wafer in the first bonding intermediate product with its other surface facing upwards on an adhesive coating platform; aligning it; and then opening a vacuum adsorption system. The adhesive coating aperture is preferably 349°, the radius is preferably 1.2 mm, the coating gap is preferably 0.15 mm, the air pressure is preferably 310 kPa, and the adhesive type is preferably "C". In this invention, the pairwise bonding is preferably performed using a Suss bonding program. Preferably, the third wafer in the third bonding intermediate product is adsorbed downwards on the platform, and the Mark points of the third bonding intermediate product are aligned and captured. The product in the first bonding intermediate product after adhesive coating is adsorbed downwards, and the Mark points of the first bonding intermediate product are aligned and captured. The two wafers are then imprinted and bonded. The resulting semi-finished products are then cured and baked sequentially to obtain the imprinted product. The curing is preferably UV curing, and more preferably carried out under ultraviolet light. The baking temperature is preferably 120-150℃, and the baking time is preferably 1-2 hours. After curing, the present invention preferably selects five points (top, middle, bottom, left, and right) of the obtained fourth bonding intermediate product to measure its bonding layer thickness 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 imprinted product.

[0059] After obtaining the imprinted product, the present invention uses a cold plating method to deposit a visible light cutoff film on the other surface of the fifth wafer in the imprinted product, thereby obtaining a coated product. The cold plating temperature is <30°C. In this invention, it is preferable to clean the other surface of the fifth wafer in the imprinted product. The cleaning is preferably performed using alcohol. In this invention, the cold plating is preferably performed in a coating apparatus, and a schematic diagram of the coating apparatus used in this invention is shown below. Figure 4 As shown, in this invention, the other surface of the fifth wafer in the imprinted product is preferably placed on the umbrella frame of the coating device with the imprinted product facing outward.

[0060] In this invention, the evaporation source for the cold plating preferably includes Ti3O5 and SiO2; the evaporation rate of the Ti3O5 is preferably... The preferred evaporation rate of the SiO2 is [preferred]. The substrate is not heated during the cold plating process, and the cold plating time is preferably 6-7 hours. In this invention, the internal temperature of the cavity is preferably monitored to be <30°C during the cold plating process. After the cold plating is completed, the transmittance of the substrate is preferably tested, and the transmittance data of the visible light cutoff film is obtained from the transmittance data of the substrate. In this invention, the transmittance data of the visible light cutoff film is preferably 420-790nm OD2; 820-970nm Tave>92%.

[0061] After obtaining the coated product, the present invention performs post-coating processing on the coated product to obtain the optical module. In the present invention, the post-coating processing preferably includes sequential cutting, lens mount application (HA), and spraying. In the present invention, the specific implementation of the cutting preferably includes: attaching one side of the fifth wafer of the coated product with the visible light cutoff film to the blue film; selecting the cutting blade model according to the product thickness; manually aligning the cutting position; setting the number of cutting blades; cutting along the edge of the photolithography frame of the photoresist pattern on the first wafer; removing the UV blue film after cutting to obtain 25 lens products. In the present invention, the specific implementation of the HA preferably includes: cleaning one side of the fifth wafer of the lens product and the CMOS surface of the chip respectively; attaching the cleaned lens product to a high-temperature adhesive tape carrier for lens loading; setting the production quantity and lens positioning; applying adhesive to the CMOS surface of the chip; the equipment gripping the edge of the fifth wafer of the lens product and attaching it to the chip; then performing UV curing; inspecting the appearance of the module; and baking. The baking temperature is preferably 120–150°C, and the baking time is preferably 1–2 hours.

[0062] In this invention, after the baking step of the HA treatment is completed, the resulting product is sprayed. In this invention, the ink composition used for spraying preferably includes ink, a curing agent, a thinner, and an additive. In this invention, the ink is preferably HF-PYB 2309-2075C spray-specific black (Dongguan Aipro Technology Co., Ltd.), the curing agent is preferably D hardener (Dongguan Aipro Technology Co., Ltd.), the thinner is preferably YC0371 thinner (Dongguan Aipro Technology Co., Ltd.), and the additive is preferably CARE73N additive (Dongguan Aipro Technology Co., Ltd.). The preferred mass ratio of the ink, curing agent, thinner, and additive in the ink composition is 10:1:8:0.3. Before spraying, the present invention preferably applies foam to the top and bottom of the HA-treated product and then attaches it to a large board. The distance between the HA-treated product and the nozzle is preferably 7-10 cm, the spraying speed is preferably 40-45 mm / s, the number of sprayings is preferably four, with the product flipped every two sprayings, and after each spraying, pre-curing and baking are performed sequentially. The pre-curing temperature is preferably 120°C and the time is preferably 15 min. The baking temperature 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 above, comprising a first wafer, a first imprinting adhesive residue layer, a first bonding layer, a second imprinting adhesive residue layer, a second wafer, a second bonding layer, a third wafer, a third imprinting adhesive residue layer, a third bonding layer, a fourth wafer, a fourth imprinting adhesive residue layer, a fourth bonding layer, a fifth wafer, and a visible light cutoff layer, which are stacked sequentially.

[0064] In this invention, in the optical module: the thickness of the first wafer is preferably 400 μm. The thickness of the first imprinted resist residue layer is preferably 461.1 μm. The thickness of the first bonding layer is preferably 30 μm. The thickness of the second imprinted resist residue 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 imprinted resist residue 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 imprinted resist residue 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] This invention does not have special requirements for the thickness of the visible light cutoff layer, as long as it meets the performance requirements of the optical module. The preferred transmittance data for the visible light cutoff film are 420–790 nm OD2; 820–970 nm Tave > 92%.

[0066] The micro-eye tracking and iris recognition optical module provided by this invention, fabricated using nanoimprint technology and cold plating process, has a pixel size of 1.4μm×1.4μm, a pixel array of 1000×1000, an 80FPS frame rate, and a maximum FOV of 120° in high frame rate mode, meeting the requirements of VR / AR devices for low power consumption and miniaturization. The nanoimprint technology is low-cost, highly efficient, and has good consistency.

[0067] This invention provides the application of the optical module described above in a miniature eye-tracking and / or iris recognition module.

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

[0069] Example 1

[0070] Imprinting followed by coating process steps:

[0071] (1) Preliminary material preparation

[0072] Mold Preparation: The mold prepared in this embodiment consists of four facet molds, namely mold S1, mold S2, mold S3, and mold S4, which together form a module. This embodiment uses a turning process to manufacture the four facet molds. The preparation method of the four facet molds includes: machining lens structures on a metal substrate with a nickel-plated surface to prepare four metal molds with different facet shapes, each mold containing a total of 25 lens patterns.

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

[0074] The preparation method of the S1 mold sub-mold includes: firstly, plasma cleaning of the quartz glass surface; secondly, preparing polydimethylsiloxane imprinting adhesive; thirdly, uniformly pouring a layer of imprinting adhesive onto the center of one side of the pre-set structural pattern of the S1 mold; fourthly, guiding the adhesive at the center point of the quartz glass; and finally, using a SUSS imprinting device (SUSS Micro Tec) to imprint the pre-set nanostructure pattern on the metal mold onto the soft template, thus obtaining a transfer template with the reverse pattern of the S1 mold structure, i.e., the S1 mold sub-mold.

[0075] The preparation methods of S2 mold sub-mold, S3 mold sub-mold and S4 mold sub-mold are basically the same as those of S1 mold sub-mold, the difference being that S2 mold, S3 mold and S4 mold are used respectively.

[0076] Photolithography of glass wafers: Clean the glass wafers, coat the upper surface of the glass wafers with photoresist, and fabricate the apertures on the corresponding photomasks onto the glass wafers through exposure and development to obtain S1 glass wafers and S3 glass wafers.

[0077] The spacing of the photolithographic pattern array on the S1 glass wafer is consistent with that of the S1 mold. The light leakage area of ​​the S1 glass wafer is a rectangular area of ​​equal length and width for a single lens, and the light-shielding area of ​​the S1 glass wafer is the cut area between the single lenses.

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

[0079] (2) Imprinting process flow

[0080] Single-sided imprinting: Using the SUSS imprinting equipment (SUSS Micro Tec), the stamp imprinting mold (MasterStamp) and glass wafers (including S1 glass wafer, S3 glass wafer and two blank glass wafers, where the blank glass wafers are glass wafers without photolithographic patterns) are vacuum adsorbed at the upper and lower positions of the imprinting machine. The imprinting adhesive is applied to the middle position of the glass wafer, and the reverse pattern of the structure on the stamp is copied and transferred to the upper surface of the imprinting adhesive layer of the wafer glass, resulting in a single-sided imprinting adhesive layer with a lens structure on the upper surface. A total of 4 imprinted single sides are obtained on the four wafer glass, namely the S1 side, S2 side, S3 side and S4 side. For S1, S2, S3, and S4 surfaces, five points (top, middle, bottom, left, and right) were selected to measure the thickness of the residual adhesive layer (imprinted surface) and the relative position data of the lens and the aperture. The refractive index of the residual adhesive layer (imprinted surface) of S1 and S4 surfaces is 1.5, and the refractive index of the residual adhesive layer (imprinted surface) of S2 and S3 surfaces is 1.7.

[0081] Pairwise bonding: The specific method for S1+S2 surface bonding includes: using a coating machine, placing the S1 surface with the imprinted side facing up on the coating platform, aligning it, and then opening vacuum adsorption. The coating nozzle diameter is 349°, radius is 1.2mm, coating gap is 0.15mm, air pressure is 310kPa, and the coating is "C" shaped. Using a SUSS imprinting device (SUSS Micro Tec), the pairwise bonding program is selected, with the S2 surface imprinted side adsorbed on top. The mark points of the S1 surface are aligned and captured. The product with the S1 surface coated is adsorbed on the bottom, and the mark points of the S2 surface are aligned and captured. S1+S2 imprint bonding is performed. After UV curing with a UV lamp, the S1+S2 surface bonded product is obtained. Five points are selected (top, middle, bottom, left, right) to measure the bonding layer thickness and the relative position data of the lenses.

[0082] The specific method for S4+S5 surface bonding includes: using a coating machine, placing the imprinted surface of the S4 surface face up on the coating platform, aligning it, and then opening the vacuum adsorption. The coating nozzle diameter is 349°, the radius is 1.2mm, the coating gap is 0.15mm, the air pressure is 310kPa, and the coating is "C" shaped. Using a SUSS imprinting device (SUSS Micro Tec), a pairwise bonding program is selected. The imprinted surface of the S5 surface (i.e., the blank glass wafer) is adsorbed on top, and the product with the S4 surface coating is adsorbed on the bottom. The mark points of the S4 surface are aligned and captured, and S4+S5 imprint bonding is performed. After UV curing with a UV lamp, the S4+S5 surface bonded product is obtained. The bonding layer thickness of the S4+S5 surface bonded product is measured at five points: top, middle, bottom, left, and right.

[0083] The specific method for S3+S4+S5 surface bonding includes: using a coating machine, placing the S3 surface with the imprinted side facing up on the coating platform, aligning it, and then opening vacuum adsorption. The coating nozzle diameter is 349°, radius is 1.2mm, coating gap is 0.15mm, air pressure is 310kPa, and the coating is "C" shaped. Using a SUSS imprinting device (SUSS Micro Tec), selecting a pairwise bonding program, the imprinted side of the S4+S5 surface bonded product is adsorbed on top, and the mark points of the S4+S5 surface bonded product are aligned and captured. The S3 surface bonded product is then adsorbed on the bottom, and the mark points of the S3 surface bonded product are aligned and captured. S3+S4+S5 imprint bonding is then performed. After UV curing with a UV lamp, the S3+S4+S5 surface bonded product is obtained. Five points are selected (top, middle, bottom, left, right) to measure the bonding layer thickness and the relative position data of the lenses.

[0084] The specific method for S1+S2+S3+S4+S5 surface bonding includes: using a coating machine, placing the S1+S2 surface-bonded product with the imprinted side facing up on the coating platform, aligning it, and then opening vacuum adsorption. The coating nozzle diameter is 349°, the radius is 1.2mm, the coating gap is 0.15mm, the air pressure is 310kPa, and the adhesive form is "C" shaped. A SUSS micro-imprinting device is used. (Tec) Select the pairwise bonding program. Adsorb the imprinting surface of the S3+S4+S5 surface-bonded product on top, and align and capture the Mark points of the S3+S4+S5 surface-bonded product. Adsorb the S1+S2 surface-bonded product after applying the adhesive on the bottom, and align and capture the Mark points of the S1+S2 surface-bonded product after applying the adhesive. Perform S1+S2+S3+S4+S5 imprint bonding. After UV curing, the S1+S2+S3+S4+S5 surface-bonded product is obtained. Select five points (top, middle, bottom, left, right) to measure the bonding layer thickness of the S1+S2+S3+S4+S5 surface-bonded product and the relative position data of the lens structure of the first bond intermediate product and the lens structure of the third bond intermediate product. After imprinting, bake the S1+S2+S3+S4+S5 surface-bonded product to obtain the imprinted product. The baking temperature is 120℃ and the baking time is 2 hours.

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

[0086] (3) Coating process flow:

[0087] Coating: Clean the S5 side of the embossed product with alcohol, then place it on an umbrella stand. Coating materials: Ti3O5, SiO2. The evaporation rate of Ti3O5 is... The SiO2 evaporation rate is The substrate was not heated, and the temperature inside the cavity was monitored to be <30℃ during the process, which lasted for 7 hours. After the cold plating was completed, the transmittance of the substrate was tested to be 420-790nm OD2; 820-970nm Tave>92%. The coated product was obtained after the cold plating was completed.

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

[0089] A schematic diagram of the coating device in this embodiment is shown below. Figure 4 As shown.

[0090] (4) Post-coating process flow

[0091] Cutting: Attach the S5 side of the coated product to the blue film, select the cutting blade model according to the product thickness, manually align the cutting position, set the number of cutting blades, and cut along the edge of the photolithography frame on the S1 side of the coated product. After cutting, remove the UV blue film to obtain 25 lens products.

[0092] A schematic diagram of the lens product prepared in this embodiment is shown below. Figure 6 As shown ( Figure 6 This diagram is only used to illustrate the layer structure of a lens product and does not represent the actual thickness of each layer in the structure.

[0093] HA: Clean the S5 side of the lens product and the CMOS side of the chip. Place the cleaned lens product onto the high-temperature adhesive tape carrier. Load the lens, set the production quantity and lens positioning, apply adhesive to the CMOS side of the chip, and the equipment will grab the edge of the S5 side of the lens product and attach it to the chip. UV cure, inspect the appearance of the module, and bake at 120℃ for 1 hour to obtain the module product.

[0094] Spraying: Prepare ink (HF-PYB 2309-2075C spraying black, Dongguan Aipro Technology Co., Ltd.), curing agent (D hardener, Dongguan Aipro Technology Co., Ltd.), thinner (YC0371 thinner, Dongguan Aipro Technology Co., Ltd.), and additive (CARE73N additive, Dongguan Aipro Technology Co., Ltd.) in a specific ratio. The mass ratio of ink, curing agent, thinner, and additive is 10:1:8:0.3. Apply foam to the top and bottom of the module product and attach it to the large board. The distance between the module product and the printhead is 7-10cm. The spraying speed is 42.5±2.5mm / s, and four coats are applied. Flip the module every two coats. After each coat, perform pre-curing (120℃, 15min) and baking (120℃, 40min) sequentially to obtain the eye-tracking optical module (optical element).

[0095] The post-coating process flow in this embodiment is as follows: Figure 5 As shown.

[0096] This embodiment uses nanoimprint technology and cold plating process to prepare a miniature eye tracking and iris recognition module with 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 high frame rate mode, which meets the requirements of VR / AR devices for low power consumption and miniaturization of the module; the nanoimprint technology is 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. Imprinting is performed first, followed by plating. A single-sided surface shape is imprinted on the surface of wafer-level optical glass using adhesive, and the surfaces are stacked using bonding adhesive. Then, a visible light cutoff film is deposited on the product surface using a cold plating process. The preparation method provided by the present invention effectively avoids the adhesive changing the lens surface shape due to heat during the plating process, and solves problems such as glass warping after imprinting and plating, inability to measure imprint alignment, and difficulty in edge cutting. The micro-eye tracking and iris recognition optical module 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 provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. Other embodiments can be obtained based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method of manufacturing an optical module, characterized by comprising: The method comprises the following steps: ​ Preparation of 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 different lens structure patterns, the sub-mold comprising a first sub-mold having a pattern opposite to the first metal mold, a second sub-mold having a pattern opposite to the second metal mold, a third sub-mold having a pattern opposite to the third metal mold and a fourth sub-mold having a pattern opposite to the fourth metal mold; Arranging imprinting glue on one surface of a first wafer, a second wafer, a third wafer and a fourth wafer, and performing imprinting by 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 respectively; 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 pitch 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 pitch as the pattern of the third sub-mold; Bonding the imprinting surface of the first wafer surface type product, the imprinting surface of the second wafer surface type product, the imprinting surface of the third wafer surface type product, the imprinting surface of the fourth wafer surface type product and a fifth wafer by using bonding glue to obtain an imprinted product; Plating a visible light cutoff film on the other surface of the fifth wafer in the imprinted product by using a cold plating method to obtain a plated product, the cold plating temperature is < 30℃, the evaporation source of the cold plating comprises Ti3O5 and SiO2, the substrate is not heated during the cold plating process, and the cold plating time is 6-7h; Performing post-plating treatment on the plated product to obtain the optical module.

2. The production method according to claim 1, characterized by, Each of the metal molds has 25 lens structure patterns.

3. The production method according to claim 1 or 2, characterized by, 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; and 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. 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; and 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.

4. The production method according to claim 1, characterized by, 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.

5. The preparation method according to claim 1, characterized in that, The bonding comprises the following steps: After drawing glue on the imprinting surface of the first wafer surface type product, the imprinting surface of the second wafer surface type product is bonded with the imprinting surface of the first wafer surface type product, and then solidified to obtain a first bonding intermediate product; After drawing glue on the imprinting surface of the fourth wafer surface type product, the imprinting surface of the fourth wafer surface type product is bonded with the fifth wafer, and then solidified to obtain a second bonding intermediate product; The imprint surface of the third wafer surface type product is painted with glue, and then the other surface of the fourth wafer in the second bonding intermediate product is bonded two by two, and then solidified to obtain a third bonding intermediate product; The other surface of the second wafer in the first bonding intermediate product is painted with glue, and then the other surface of the third wafer in the third bonding intermediate product is bonded two by two, and then solidified and baked in sequence to obtain the imprinted product.

6. The method of claim 1, wherein, The preparation method of the sub-mold comprises the following steps: An imprint glue is arranged on one side of the metal mold with a lens structure pattern, a drainage glue is added at the center point of the quartz glass, and then the imprinting is performed to obtain a sub-mold with a pattern opposite to that of the metal mold; the sub-mold comprises 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 production method according to claim 6, wherein The imprint glue is a polydimethylsiloxane imprint glue.

8. The method of claim 1, wherein, The evaporation rate of the Ti3O5 is 3.5±0.2 Å / S, and the evaporation rate of the SiO2 is 8±0.2 Å / S.

9. The optical module prepared by the method according to any one of claims 1 to 8, characterized in that, The first wafer, the first imprint glue residual layer, the first bonding layer, the second imprint glue residual layer, the second wafer, the second bonding layer, the third wafer, the third imprint glue residual layer, the third bonding layer, the fourth wafer, the fourth imprint glue residual layer, the fourth bonding layer, the fifth wafer, and the visible light cutoff layer are sequentially stacked.

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

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