CN112817074A

CN112817074A - Optical collimator, manufacturing method thereof and imaging device with optical collimator

Info

Publication number: CN112817074A
Application number: CN202110035860.9A
Authority: CN
Inventors: 宋珺
Original assignee: Suzhou Qunye New Material Technology Co ltd
Current assignee: Suzhou Qunye New Material Technology Co ltd
Priority date: 2021-01-12
Filing date: 2021-01-12
Publication date: 2021-05-18

Abstract

The invention provides an optical collimator, a preparation method thereof and optical fingerprint identification equipment with the optical collimator. The optical collimator includes: a plurality of groups of collimation units which are arranged in a stacked mode; the collimating unit comprises a transparent light guide layer forming a collimating light transmitting channel and a light absorbing layer containing a light absorbing material; and a collimated light transmission channel is formed between the adjacent light absorption layers, the light absorption layers have an absorption cut-off band with the width of at least 50nm within the wavelength range of 300-1200nm, and the light transmission rate within the wavelength range of the absorption cut-off band is less than or equal to 1%. The light absorption layer can absorb stray light and only allow the light in the direction parallel to the collimated light transmission channel to pass through, so that the optical collimation and peep prevention effects are realized; in addition, the light rays which can pass through the specific wavelength range of the optical collimator are selected through the absorption cut-off band of the light absorption layer, and the light rays can pass through the specific wavelength range of the specific spectrum according to the permission; the further light absorbing material layer is provided with hard spacers, which are used for controlling the thickness distribution uniformity of the light absorbing layer within 5 percent.

Description

Optical collimator, manufacturing method thereof and imaging device with optical collimator

Technical Field

The invention relates to the technical field of optics, in particular to an optical collimator, a preparation method thereof and imaging equipment with the optical collimator.

Background

With the rapid development of electronic devices, people pay more and more attention to fingerprint identification technology. For the common capacitive fingerprint identification technology in the market at present, the influence of penetrating thickness and wet fingers is avoided, the position of the fingerprint identification device on the electronic equipment is greatly limited, and the screen occupation ratio of the electronic equipment is influenced.

The optical fingerprint identification technology is to collect reflected light formed by the reflection of light rays emitted by a light source on a finger through an optical fingerprint sensor, wherein the reflected light carries fingerprint information of the finger, so that the fingerprint identification is realized. Compare in capacitanc fingerprint identification device, the requirement of optics fingerprint identification device to the screen thickness of electronic equipment is lower to the position of placing can be more nimble on electronic equipment, can improve the screen of electronic equipment moreover and account for than. To achieve these advantages, optical components such as an optical fingerprint sensor and an optical collimator are required to be included in the optical fingerprint recognition apparatus. For the optical fingerprint recognition module, a collimator is usually provided to guide the reflected light reflected from the surface of the finger to the image sensor below for optical detection.

The collimator may be a separate optical component (discrete) or may be integrated in the image sensor (integrated). The discrete collimator has the advantage of achieving high aspect ratios, such as Through Silicon Vias (TSVs) fabricated by a Through Silicon Via (TSV) process, but has the disadvantage of being costly. The integrated collimator is realized based on a Metal layer in a Complementary Metal Oxide Semiconductor (CMOS) post process, which has the advantage of no additional process cost, but the depth-to-width ratio of the light-transmitting channel is difficult to further improve because the thickness and the opening size of the Metal layer are limited by the process. For Augmented Reality (AR) technology, fingerprint identification and other biological identification technologies, special light sources are used; the transmission of the light source is collimated bandpass gated to prevent leakage and transmission errors; errors in the signals and damage to and negative effects on peripheral devices, and the precision of the light-transmitting channels of the optical collimator is difficult to control. The present invention is based on the finding that the requirements are difficult to meet with existing optical collimators.

Disclosure of Invention

The invention mainly aims to provide an optical collimator, a preparation method thereof and biological identification equipment with the optical collimator, and aims to solve the problems that the optical collimator in the prior art is not high in manufacturing cost, is not difficult to improve the depth-to-width ratio and is difficult to meet the requirement of carrying out collimation band-pass gating on the transmission of a light source.

In order to achieve the above object, according to one aspect of the present invention, there is provided an optical collimator including:

a plurality of groups of collimation units which are arranged in a stacked mode;

the collimating unit comprises a transparent light guide layer forming a collimating light transmitting channel and a light absorbing layer containing a light absorbing material; and a collimated light transmission channel is formed between the adjacent light absorption layers, the light absorption layers have an absorption cut-off band with the width of at least 50nm within the wavelength range of 300-1200nm, and the light transmission rate within the wavelength range of the absorption cut-off band is less than or equal to 1%.

In a preferable technical scheme, the light absorption layer has an absorption cut-off band with a width of at least 100nm within a wavelength range of 300-1200nm, and the light transmittance within the wavelength range of the absorption cut-off band is less than or equal to 1 percent;

preferably, the light absorption layer has an absorption cut-off band with a width of at least 150nm in the wavelength range of 300-1200nm, and the light transmittance in the wavelength range of the absorption cut-off band is less than or equal to 1%;

preferably, the light absorption layer has an absorption cut-off band with a width of at least 200nm in the wavelength range of 300-1200nm, and the light transmittance in the wavelength range of the absorption cut-off band is less than or equal to 1%;

preferably, the light absorption layer has an absorption cut-off band with a width of at least 250nm in the wavelength range of 300-1200nm, and the light transmittance in the wavelength range of the absorption cut-off band is less than or equal to 1%;

preferably, the light absorption layer has an absorption cut-off band with a width of at least 300nm in the wavelength range of 300-1200nm, and the light transmittance in the wavelength range of the absorption cut-off band is less than or equal to 1%;

preferably, the wavelength range of the absorption cut-off band is 350-700 nm, and the light transmittance in the wavelength range of the absorption cut-off band is less than or equal to 1%; the wavelength range of the absorption cut-off band is 300-400 nm, and the light transmittance in the wavelength range of the absorption cut-off band is less than or equal to 1%; the wavelength range of the absorption cut-off band is 400-700nm, and the light transmittance in the wavelength range of the absorption cut-off band is less than or equal to 1%; the wavelength range of the absorption cut-off band is 350-600 nm, and the light transmittance in the wavelength range of the absorption cut-off band is less than or equal to 1%;

the light transmittance of the absorption layer in the wavelength range of 800-1200nm is more than or equal to 80 percent; preferably, the light transmittance in the wavelength range of 850-1100nm is 80% or more; preferably, the light transmittance in the wavelength range of 850-1100nm is greater than or equal to 85%; preferably, the light transmittance in the wavelength range of 850-1100nm is 90% or more.

In a preferred technical scheme, the light absorbing material is selected from a plurality of squarylium organic dyes, phthalocyanine organic dyes, nitrobenzamines dyes, aminoketones dyes, anthraquinones dyes, quinolines dyes, triazines dyes, benzothiazoles dyes and coumarins dyes, iron-chromium inorganic dyes, cobalt-copper inorganic dyes and chromium inorganic dyes.

In the preferred technical scheme, the light absorption material accounts for 0.1-70% by weight of the light absorption layer (20), and preferably 10-50%.

In a preferred technical scheme, the transparent light guide layer (10) is selected from optical glass and a high-molecular optical film; the material of the high-molecular optical film comprises acrylate, epoxy resin, polycarbonate, polystyrene, polyethylene terephthalate, cellulose triacetate or polyimide; preferably, the light transmittance of the transparent light guide layer in the wavelength range of 350-1000nm is more than 90%; preferably, the organic transparent material is selected from a cyclic polyolefin layer or a transparent polyimide layer; preferably, the thickness of the transparent light guide layer (10) is 1-300 μm; the thickness precision of the transparent light guide layer is controlled to be +/-5%. Preferably, the cross-sectional shape of the optical collimator is S-shaped, C-shaped or linear; preferably, the optical collimator is a rigid or flexible member.

In the preferred technical scheme, the light absorption layer comprises 60-90 parts of resin material, 0.0001-5 parts of light absorption material and 0-20 parts of hard spacing body by weight; preferably, the light absorption layer is made of a resin material selected from any one of epoxy resin, silicone resin, acrylic resin, PI resin, polyurethane and PU resin, acrylate, epoxy resin, polycarbonate, polystyrene, cellulose triacetate, polyethylene terephthalate, or polyimide; preferably, the thickness of the light absorbing layer is 1-30 μm; the thickness precision of the light absorption layer is controlled to be +/-5%; preferably, the shape of the hard spacer is selected from the group consisting of spherical, columnar, rod-like, net-like; preferably, the thickness of the hard spacer is 1 μm to 30 μm.

In a preferred technical scheme, the ratio of the thickness of the transparent light guide layer to the thickness of the light absorption layer in the collimation unit is 1: 1-10: 1; the ratio of the channel width (W) to the channel depth (L) of the collimated light transmitting channels is in the range of 1: 30-1: 5.

another object of the present invention is to provide a method for manufacturing an optical collimator, comprising the steps of:

s1, providing a transparent light guide layer material to form a transparent light guide layer with a preset thickness;

s2, stirring and mixing the raw materials including the resin material and the light absorbing material to obtain a coating liquid; coating the coating liquid on a transparent light guide layer, namely forming a light absorption layer (20) formed by the coating liquid on the transparent light guide layer;

and S3, laminating a plurality of layers of collimation units, and then extruding and curing to form the optical collimator.

In a preferred embodiment, the method further includes a step of adding a predetermined amount of hard spacers in step S2 and mixing them uniformly.

It is a further object of the present invention to provide an optical imaging apparatus comprising an optical sensor and the optical collimator set on a light-sensitive side of the optical sensor.

By applying the technical scheme of the invention, the invention provides an optical collimator, which comprises: a plurality of groups of collimation units which are arranged in a stacked mode; the collimating unit comprises a transparent light guide layer forming a collimating light transmitting channel and a light absorbing layer containing a light absorbing material; and a collimated light transmission channel is formed between the adjacent light absorption layers, the light absorption layers have an absorption cut-off band with the width of at least 50nm within the wavelength range of 300-1200nm, and the light transmission rate within the wavelength range of the absorption cut-off band is less than or equal to 1%. The light absorption layer can absorb stray light and only allow the light in the direction parallel to the collimated light transmission channel to pass through, so that the optical collimation effect is realized; in addition, the light rays in a specific wavelength range of the optical collimator can be selected through the absorption cut-off band of the light absorption layer, and the light rays in the specific spectral wavelength range can be captured by the optical sensor arranged below the collimator according to the special light source allowing the specific spectral wavelength range to pass. These light rays of specific spectral wavelengths allow, for example, a wavelength range in the infrared band, so that abnormality of superficial skin and the like can be detected at the same time as fingerprint recognition. In addition, the light absorption layer can only allow the visible light rays parallel to the light transmission channels to pass through, and the peep-proof effect can also be achieved.

In addition to the objects, features and advantages described above, other objects, features and advantages of the present invention are also provided. The present invention will be described in further detail below with reference to the drawings.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 is a schematic cross-sectional view of an optical collimator according to an embodiment of the present invention;

FIG. 2 is a schematic cross-sectional view of another optical collimator provided in accordance with an embodiment of the present invention;

FIG. 3 is a schematic cross-sectional view of another optical collimator provided in accordance with an embodiment of the present invention;

FIG. 4 is a schematic cross-sectional view of another optical collimator provided in accordance with an embodiment of the present invention;

FIG. 5 is a schematic cross-sectional view of another optical collimator provided in accordance with an embodiment of the present invention;

FIG. 6 is a schematic cross-sectional view of another optical collimator provided in accordance with an embodiment of the present invention;

FIG. 7 is a schematic cross-sectional view of another optical collimator provided in accordance with an embodiment of the present invention;

and the number of the first and second groups,

FIG. 8 is a graph of transmittance versus wavelength for different incident light angles for the light absorbing layer of the optical collimator of the present invention.

Wherein the figures include the following reference numerals:

10. a transparent light guide layer; 20. a light absorbing layer; 30. a hard spacer.

Detailed Description

It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged under appropriate circumstances in order to facilitate the description of the embodiments of the invention herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

As described in the background art, the optical collimator in the prior art is expensive to manufacture, difficult to increase the aspect ratio, difficult to control the thickness precision of the collimated light transmitting channel and the collimated light non-transmitting channel, and easy to generate leakage and transmission error when used for transmission of special light sources; in addition, the conventional optical collimator does not have a band-pass gating function, transmission of special signals cannot be realized, and the special signals have large errors, so that the problems of damage, negative influence and the like on peripheral devices are solved. The inventor of the present invention has studied the above problems and proposed an optical collimator comprising a plurality of sets of collimating units arranged in a stack; the collimating unit comprises a transparent light guide layer forming a collimating light transmitting channel and a light absorbing layer containing a light absorbing material; and a collimated light transmission channel is formed between the adjacent light absorption layers, the light absorption layers have an absorption cut-off band with the width of at least 50nm within the wavelength range of 300-1200nm, and the light transmission rate within the wavelength range of the absorption cut-off band is less than or equal to 1%.

Have the extinction material in the light-absorbing layer among the above-mentioned optical collimator, the light-absorbing layer can regard as general shading material to use, forms the traditional optical collimator that transparent leaded light layer, light-absorbing layer interval set up like this, can realize traditional collimated light effect. In addition, the light absorbing materials used in the light absorbing layer of the present invention are selected and arranged such that after the absorption spectra of the light absorbing materials are superimposed, the superposition of the absorption spectra of the light absorbing materials can form an absorption cut-off band having a width of at least 50nm in the wavelength range of 300-1200nm, and the light transmittance in the wavelength range of the absorption cut-off band is 1% or less. The light absorption layer does not curve drift along with the large incident angle of light rays, so that the curve drift of the optical collimator is very small under the irradiation of the incident light rays at different angles, and the requirement of an optical sensor on the large-angle drift value of the optical collimator can be met. In the actual measurement process, the absolute value of the difference from the wavelength value at which the light transmittance measured perpendicular to the light absorbing layer is 50% with respect to the wavelength value at which the light transmittance measured perpendicular to the light absorbing layer is 50% is less than 10 nm. More preferably, the absolute value of the difference in wavelength value at which the light transmittance measured from the light absorbing layer at a perpendicular direction is 50% is less than 8nm with respect to the wavelength value at which the light transmittance measured from the light absorbing layer at a perpendicular direction is 35 °. Even more, the absolute value of the difference in the wavelength value at which the light transmittance is 50% as measured from an angle at which the wavelength value at which the light transmittance is 50% as measured perpendicular to the light absorbing layer is 35 ° with respect to the perpendicular direction of the light absorbing layer is less than 5 nm.

In another embodiment of the present invention, the light absorbing material used in the light absorbing layer is capable of absorbing visible light to reduce the transmittance of visible light to 1% or less, and has a wavelength value of 50% light transmittance in the wavelength range of 560 to 800nm, and the absolute value of the difference in wavelength value of 50% light transmittance measured from the wavelength value of 50% light transmittance measured perpendicular to the light absorbing layer at an angle of 35 ° with respect to the perpendicular direction of the light absorbing layer is less than 10nm, such an optical collimator having excellent ultraviolet and visible light cut-off effects, and the near infrared band maintaining good light transmittance.

In the optical collimator of the present invention, the light absorbing material of the light absorbing layer can absorb light in any wavelength range within 300-. Because the light absorption layer adopts the light absorption material, the curve can be fixed, and the phenomenon of cut-off curve drift caused by large-angle incident light is prevented. In order to effectively prevent the phenomenon of cut-off curve shift caused by large-angle incident light, the light absorbing material preferably has a weight content of 0.1% to 70%, preferably 10% to 50%, in the light absorbing layer 20.

Preferably, the light absorbing material is selected from a plurality of squarylium organic dyes, phthalocyanine organic dyes, nitrobenzophenone dyes, aminoketone dyes, anthraquinone dyes, quinoline dyes, triazine dyes, benzothiazole dyes and coumarin dyes, iron-chromium inorganic dyes, cobalt-copper inorganic dyes and chromium inorganic dyes. The light absorption material not only can superpose absorption spectra to cut off visible light, but also can play a role in preventing a light transmittance curve from drifting leftwards under the condition of a large visual angle and preventing the curve of large-angle irradiation from drifting.

In another embodiment of the present invention, the transparent light guiding layer 10 is optical glass, organic glass, or a transparent organic material, such as a cyclic polyolefin layer (COP) or a transparent polyimide layer (PI). Optical glass, which has a high light transmittance, can be a preferred substrate material. The cyclic polyolefin layer (COP) or the transparent polyimide layer (PI) not only has high toughness and mechanical properties, but also has excellent compatibility with the above preferred light absorbing materials, both COP and PI materials, and is not easy to precipitate. When the hard optical glass is used, the thickness error can be controlled within 10 micrometers, the optical glass is obtained in a wire cutting mode, then fine grinding and polishing are carried out, and the thickness of the transparent light guide layer is controlled within the range of 100 micrometers-3 mm. When a polymer optical film is used, the optical film may be an acrylate film, an epoxy resin film, a polycarbonate film, a polystyrene film, a polyethylene terephthalate (PET) or polyimide film, a Triacetyl Cellulose (TAC) film; these optical films can be completed by extrusion or casting, followed by biaxial stretching. The high polymer material can be acrylic, PET, TAC, PI and other materials, the thickness of the optical film can be controlled within 2-100 mu m by extrusion and casting processes, even can reach 1 micron, and the thickness precision can be controlled within +/-5%.

In the optical collimator of the present invention, in order to ensure the controllable precision of the transparent light guide layer and the light absorption layer of the optical collimator, the transparent light guide layer is preferentially prepared. The transparent light guide layer is preferably made of a transparent material with preset hardness and stiffness, and the transparent light guide layer is prepared into the required thickness of the transparent light guide layer in advance. Controlling the thickness of the transparent light guide layer (10) to be 1-300 mu m; the thickness precision of the transparent light guide layer is controlled to be +/-5%. A light absorbing layer is then prepared. After forming the uncured collimation unit, laminating the collimation unit, extruding the collimation unit to enable the whole surface of the collimation unit to be pressed, and controlling the thickness of the light absorption layer by controlling the pressure and the viscosity of coating liquid of the light absorption layer, so that the thickness of the obtained light absorption layer is controlled to be uniform, and the thickness of the light absorption layer is 1-30 mu m; the thickness precision of the light absorption layer is controlled to be +/-5%.

In another embodiment of the present invention, the transparent light guide layer is prepared to have a required thickness, i.e. the thickness of the transparent light guide layer (10) is controlled to be 1-300 μm; the thickness precision of the transparent light guide layer is controlled to be +/-5%. A light absorbing layer is then prepared. Different from the above, the coating liquid used for the light absorbing layer contains hard spacers, and the shape of the hard spacers is selected from the group consisting of spherical, columnar, rod-like, and net-like; preferably, the thickness of the hard spacer is 1 μm to 30 μm. The hard spacer may have a predetermined hardness to prevent chipping in a subsequent process. The hard spacers may have a predetermined light transmittance, such as a transmittance of 70% or more, preferably a transmittance of 75% or more, preferably a transmittance of 80% or more, preferably a transmittance of 85% or more, preferably a transmittance of 90% or more. After forming the uncured collimation unit, laminating the collimation unit, extruding the collimation unit to enable the whole surface of the collimation unit to be pressed, and controlling the thickness of the light absorption layer by controlling the size of the pressure, the shape of the hard spacer and the viscosity of the coating liquid of the light absorption layer, so that the thickness of the obtained light absorption layer is controlled to be more uniform, wherein the thickness of the light absorption layer is 1-30 mu m; the thickness precision of the light absorption layer is controlled to be +/-5%. More precisely, the thickness of the light-absorbing layer is between 1 and 30 μm; the thickness precision of the light absorption layer is controlled to be +/-4%. Even the accuracy of the thickness of the light absorbing layer is controlled within a range of ± 3%, even the accuracy of the thickness of the light absorbing layer is controlled within a range of ± 2%, and even the accuracy of the thickness of the light absorbing layer is controlled within a range of ± 1%.

The present inventors found that shape and size control of the hard spacers is more excellent. The hard SPACERs may be commercially available SPACER particles, SPACER Powder (SPACER), and the SPACER particles have a more uniform particle size control, and thus, may serve to control the thickness of the light absorbing layer after being uniformly dispersed in the light absorbing layer. The spacer particles may employ glass beads, PMMA particles, melamine particles, ceramic material beads, or the like. The selection of the spacer requires consideration of the mixing performance of the spacer and the coating liquid, in addition to the requirement in terms of particle diameter. The present inventors have studied and found that the dispersion property of the spacer in the coating liquid, the adhesion to the coating liquid, and the like are important indexes of the spacer. The spacer particles of the present invention preferably use glass beads, which have high fluidity in a coating liquid, good uniform dispersibility, and good hardness. For the overall stiffness of the rigid spacers, it is also possible to use net-like spacers or rod-like spacers, for example, mesh plates of uniform thickness.

In another embodiment of the present invention, the coating liquid used for preparing the light absorbing layer may include a resin material, a light absorbing material, and the above-described hard spacer for controlling the thickness of the light absorbing layer. The resin material can select different resins according to the material of the transparent light guide layer. The resin material can be selected from organic silicon, acrylic resin, polyurethane, PU resin and epoxy resin; such as acrylic resins and/or methyl isobutyl ketone, and the like. The preferred resin material may be one or more of acrylate, methacrylic acid derivative, modified epoxy acrylate, urethane acrylate and aromatic urethane acrylate. The preferred resin material may be one or more of a mixture of polyurethane and octyl acrylate, aromatic urethane acrylate, cresol novolac epoxy acrylate, bisphenol a diacrylate resin, and urethane based aromatic amines. When the transparent light guide layer is transparent glass, a silane coupling agent may be added, for example, typical silane coupling agents are KH550, KH570, KH560, a151 (vinyltriethoxysilane), a171 (vinyltrimethoxysilane), a172 (vinyltris (. beta. -methoxyethoxy) silane), and the like.

The light absorption material is adapted according to the selection of the absorption cut-off band, the 300-1200 wavelength full-waveband absorption material can be carbon powder, iron, cobalt and copper inorganic dyes, and the phthalocyanine and squaric acid heavy-metal-free material can be selected for partial waveband absorption. Preferably, the light absorbing material is selected from a plurality of squarylium organic dyes, phthalocyanine organic dyes, nitrobenzophenone dyes, aminoketone dyes, anthraquinone dyes, quinoline dyes, triazine dyes, benzothiazole dyes and coumarin dyes, iron-chromium inorganic dyes, cobalt-copper inorganic dyes and chromium inorganic dyes. After the light absorption materials are selected, absorption spectra are superposed to form a special absorption cut-off band which can be adapted to the requirements of special light sources.

The laminated layers of the collimation units of the transparent light guide layer and the light absorption layer can reach more than 500 layers, and the transparent light guide layer has uniform thickness and controllable precision; the light absorption layer is uniform in thickness and controllable in precision, and the laminated layers are uniformly distributed. The light-transmitting channel is uniform in whole after the multiple layers are overlapped, the thickness distribution of the light-absorbing layer used as light blocking or partial waveband cutoff is controllable and uniform, if the thickness of the transparent light-guiding layer is 100 micrometers, the thickness of the light-transmitting layer is between 95 and 105 micrometers when the multiple layers are overlapped to more than 1000 layers, and if the light-absorbing layer is 10 micrometers, the statistical thickness range is between 9.5 and 10.5 micrometers after the multiple layers are overlapped.

In addition, the thickness ratio of the transparent light guide layer to the light absorption layer can be adjusted, and the thickness of the light absorption layer can be accurately controlled according to the hard spacer, the viscosity of coating liquid of the light absorption layer and the pressure control of extrusion extension; the transparent light guide layer is pre-processed to be in a preset thickness, the thickness and the geometric dimension of the shading light and the transparent light guide layer are controlled to obtain the thickness proportion of the transparent light guide layer and the light absorption layer, so that the ratio of the light transmission section area to the shading section area of the optical collimator can be changed, and controllable light transmittance is obtained.

In the preparation method, the resin material, the light absorption material and the hard spacer can be stirred together to obtain a coating liquid, the coating liquid is coated on the transparent light guide layer to obtain a wet film, and the thickness of the wet film of the coating liquid is 5-250 microns to obtain an uncured collimation unit; several (500-1000) such uncured collimating units are prepared to be stacked into a stack. Then, the extrusion and extension operation is performed. And (5) extruding, extending to a preset thickness, curing and drying. And finally cutting and carving into a required shape. In this way, the light absorbing material can have better adhesion to the material of the transparent light guiding layer 10 without being precipitated. On the other hand, the light-absorbing material can be uniformly dispersed by adopting a thermosetting mode, the film is formed uniformly, and the reliability of the product after high temperature, high humidity and ultraviolet irradiation is better. The light absorption material is arranged on the light absorption layer 20, so that the band pass of the light transmittance curve of the optical collimator does not drift along with the incident large-angle light, and the curve drift of the optical collimator is very small under the irradiation of the incident light at different angles, thereby meeting the requirement of the sensor on the large-angle drift value of the optical collimator.

The method of applying the coating liquid to the transparent light guide layer may be: roller coating, knife coating, slit coating, spin coating, screen printing, flexographic printing and other modes, and the more preferable mode is that the spin coating can achieve better surface effect. The coated material is cured, preferably by thermal curing. The light absorption material accounts for 0.1-70% of the light absorption layer by weight, and preferably 10-50% of the light absorption layer by weight. The light absorption material can cut off the light in the preset waveband within the wavelength range of 300-1200nm, so that the light transmittance curve of the optical collimator in the preset waveband is fixed and does not drift along with the change of the incident light angle.

In the optical collimator, the transparent light guide layer of the optical collimator adopts the optical glass and the polymer optical film, so that the mechanical property of the optical collimator can be improved, and the collimation effect of the optical collimator can be effectively improved. The optical glass and the polymer optical film can have preset stiffness, after the plurality of collimating units are superposed into the optical collimator, the optical collimator is cut, carved and other processes according to the use scene of the optical collimator to form a preset shape, and various application scenes such as hand-held type, wearable type and projection type are met.

According to another aspect of the present invention, there is provided an optical fingerprint recognition system, comprising an optical sensor and the optical collimator, wherein the optical collimator is disposed on a light-sensitive side of the optical sensor. The optical fingerprint identification system utilizes the refraction and reflection principle of light, and the light that the light source jetted out refracts angle and reflection go back on the uneven line of finger surface fingerprint is different in light and shade, and the corresponding picture information that can collect different light and shade degrees of optical sensor to accomplish the collection of fingerprint. Through the staggered stacking of the light absorption layers of the adjacent collimation units, the width of a light transmission channel in the formed collimator is reduced, and therefore the collimation effect of the collimator is ensured. Because the light absorbing layer is made of resin flexible material, the thickness of each light absorbing layer can be very thin and light, so that the total thickness of the light collimator is reduced and the light collimator is thinner. A light collimator based on this characteristic easily fulfills the need for a large area. Because the flexible light absorption layers which are stacked in multiple layers are adopted, the light absorption layers of all the layers can be thinner, so that the side wall of the light transmission channel is better in appearance, and the light transmission channel has an excellent collimation effect.

In addition, because the light absorption material arranged on the light absorption layer in the optical collimator can filter stray light and enable parallel collimated light to penetrate through, and the light absorption material of the light absorption layer forms a light absorption stop band, so that the optical collimator can transmit signals of a special light source, response information of the special light source is increased, sensor leakage and transmission errors below the optical collimator can be reduced, and damage and negative effects on peripheral devices can be reduced. More particularly, due to the light absorption material arranged on the light absorption layer, the special light sources do not drift along with incident large-angle light rays, so that the curve drift of the optical collimator is very small under the irradiation of the incident light at different angles, and the requirement of the sensor on the large-angle drift value of the optical collimator can be met.

The optical collimator and the method for manufacturing the same according to the present invention will be further described with reference to the following examples.

Example 1

As shown in fig. 1 and 2, the present embodiment provides an optical collimator including: 100 sets of collimating units (not all shown) arranged one above the other; the collimating unit includes a transparent light guiding layer 10 forming a collimated light transmitting channel and a light absorbing layer 20 containing a light absorbing material; collimated light transmitting channels are formed between adjacent light absorbing layers 20.

The transparent light guide layer 10 is transparent glass, and the material of the transparent substrate is optionally crystal, borosilicate glass, and the like, and specifically can be D263T, AF32, EagleXG, H-ZPK5, H-ZPK7, and the like. For example, the transparent light guide layer 10 may be a transparent sheet, the left-right direction in fig. 1 is the thickness direction of the transparent sheet, the left side and the right side of the transparent sheet are opposite, and the thickness of the transparent light guide layer is 200 μm.

The light absorption layer adopts coating liquid containing light absorption materials, and is a flowing material. The transparent light guide layer is a part for transmitting light and needs high transmittance and more uniform material. The preparation method of the optical collimator takes the transmission layer as a main layer: the transparent light guide layer is firstly completed, the thickness and the size are well controlled, then the light absorption layer is added on the basis of the transparent light guide layer, the thickness is controlled, and then the material is finished by reciprocating stacking.

The purchased D263T glass was first cut, ground and polished to obtain a 200 μm transparent light guide layer.

Then adding 100g of ternary acrylic resin, 800g of cyclohexanone and 10 g of carbon black with the particle size of 100nm together, mixing and stirring at 2000RPM for one hour, adding a thermosetting initiator, stirring for 1 hour until the mixture is completely dissolved to obtain a light absorption layer coating liquid, and standing or defoaming the coating liquid in vacuum for 6 hours.

Coating the coating liquid on the transparent light guide layer by using a doctor blade coating process to form a collimating unit, and then attaching until the expected number of layers is reached.

And extruding, extending and processing to the required thickness of the optical collimator by using an extrusion die device, and then putting the optical collimator into an oven for drying and curing to obtain the optical collimator. And cutting and engraving the optical collimator to obtain a usable hard optical collimator product.

The obtained optical collimator can realize the collimation of a plane light source, eliminate the entrance of light noise at other angles through angle control, and simultaneously design parallel light transmission devices with various light transmittance sizes according to requirements. As shown in fig. 1, W is the channel width of the light-transmitting channel of the optical collimator, and L is the channel depth of the light-transmitting channel of the optical collimator. The depth of the light-transmitting channels can be adjusted by precisely cutting the optical collimator (actually, the length of the plane sides of the stack), so that the width-to-length ratio of the light-transmitting channels can be adjusted.

Example 2

As shown in fig. 3, the present embodiment provides an optical collimator including: 100 sets of collimating units (not all shown) arranged one above the other; the collimating unit includes a transparent light guiding layer 10 forming a collimated light transmitting channel and a light absorbing layer 20 containing a light absorbing material; collimated light transmitting channels are formed between adjacent light absorbing layers 20.

Wherein transparent leaded light layer 10 is PMMA organic glass, and is exemplary, and transparent leaded light layer 10 can be the transparent lamellar body, and the left and right sides direction in figure 1 is the thickness direction of transparent lamellar body, and the left side and the right side of transparent lamellar body are relative, and the thickness of transparent leaded light layer is at 200 μm.

First, a PMMA plexiglass sheet of 0.4mm (Coly) thickness is purchased.

Then, an appropriate amount of acrylic resin (Mitsubishi resin) and 800g of MIBK, 10 g of 100 nanometer carbon black and glass beads are mixed and stirred at 2000RPM for 1h until the mixture is completely uniform to obtain a light absorption layer coating liquid, and the coating liquid is kept stand or defoamed in vacuum for 6 h.

Coating the coating liquid on the transparent light guide layer by using a silk-screen process to form a collimation unit and stacking the collimation unit to the expected number of layers;

and extruding, extending and processing to the required thickness of the optical collimator by using an extrusion die device, and then putting the optical collimator into an oven for drying and curing to obtain the optical collimator. Cutting and engraving the optical collimator to obtain a usable product, as shown in fig. 3.

Example 3

As shown in fig. 4 and 5, the present embodiment provides an optical collimator including: 100 sets of collimating units (not all shown) arranged one above the other; the collimating unit includes a transparent light guiding layer 10 forming a collimated light transmitting channel and a light absorbing layer 20 containing a light absorbing material; collimated light transmitting channels are formed between adjacent light absorbing layers 20.

Wherein the transparent light guiding layer 10 is a PET film. For example, the transparent light guide layer 10 may be a transparent sheet, the left-right direction in fig. 1 is the thickness direction of the transparent sheet, the left side and the right side of the transparent sheet are opposite, and the thickness of the transparent light guide layer is 50 μm.

Optical grade PET film was first purchased at 100 microns (KIMOTO).

Then stirring 100g of transparent acrylic resin, 800g of MIBK and 100nm carbon black for 1h until the transparent acrylic resin is completely dissolved to obtain a light absorption layer coating liquid, and standing or defoaming the coating liquid in vacuum for 6 h.

Coating the coating liquid on the transparent light guide layer by using a scraper coating process to form a collimation unit, and then laminating the collimation unit to reach the expected number of layers;

and finally, overlapping 200 collimation units, extruding and extending by using extrusion die equipment to the required thickness of the optical collimator, and then putting the collimator into an oven for drying and curing to obtain the flexible optical collimator.

Example 4 (UV for example with optical barrier)

As shown in fig. 6 and 7, the present embodiment provides an optical collimator including: 100 sets of collimating units (not all shown) arranged one above the other; the collimating unit includes a transparent light guiding layer 10 forming a collimated light transmitting channel and a light absorbing layer 20 containing a light absorbing material; collimated light transmitting channels are formed between adjacent light absorbing layers 20.

Then 100g of ternary acrylic resin, 800g of MIBK and 50 g of UV328 (Basff) are added together and uniformly mixed, and a proper amount of hard spacer 30 glass microspheres are stirred for 1h until the glass microspheres are completely dissolved to obtain a light absorption layer coating liquid, and the coating liquid is kept stand or defoamed in vacuum for 6 h.

The coating liquid is coated on the transparent light guide layer by using a doctor blade coating process, and a UV section absorption layer is formed to be attached on the transparent layer, and the above is laminated to a desired thickness.

And extruding and extending the optical collimator to the required thickness by using an extrusion die device, and then putting the optical collimator into an oven for drying and curing to obtain the optical collimator with the UV waveband.

The spacer layer can be extruded to flow by the spacer material 30 to realize the precise control of the spacer layer, and the thickness control of each spacer layer is completed by extrusion; the thickness control of the laminated optical device can be realized by prefabricating the transparent light guide layer, carrying the light absorption layer which can flow or partially flow and contains the spacing material, and the uniform thickness distribution is realized; the obtained optical collimator can realize the collimation of a plane light source, eliminate the entrance of light noise at other angles through angle control, and simultaneously design parallel light transmission devices with various light transmittance sizes according to requirements.

The absorbance layer was prepared by using lambda1050 spectrophotometer to test the transmittance-wavelength relationship curve of the sample under the conditions of 0 ° and 35 °, especially taking the substrate sample prepared in example 2 as an example, the test result is shown in fig. 8, and the measured optical transmittance curves are consistent under the irradiation of incident light with different incident angles.

From the above description, it can be seen that the above-described embodiments of the present invention achieve the following technical effects: the optical collimator comprises the light absorption material arranged in the light absorption layer, so that the absorption cut-off band curve of the optical collimator does not drift along with incident large-angle light, and the absorption cut-off band curve of the optical collimator has very small drift under the irradiation of incident light at different angles, and the requirement of the sensor on the large-angle drift value of the optical collimator can be met.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An optical collimator, characterized in that it comprises:

2. The optical collimator of claim 1,

the light absorption layer has an absorption cut-off band with a width of at least 100nm within a wavelength range of 300-1200nm, and the light transmittance within the wavelength range of the absorption cut-off band is less than or equal to 1 percent;

3. An optical collimator according to claim 2, characterized in that the light absorbing material is preferably selected from a plurality of squarylium organic dyes, phthalocyanine organic dyes, nitrobenzamines dyes, aminoketones, anthraquinones, quinolines, triazines, benzothiazoles and coumarins, iron-chromium inorganic dyes, cobalt-copper inorganic dyes, chromium inorganic dyes.

4. Optical collimator according to claim 1, characterized in that the light absorbing material is present in the light absorbing layer (20) in an amount of 0.1% to 70%, preferably 10% to 50% by weight.

5. The optical collimator as claimed in claim 1, characterized in that the transparent light guiding layer (10) is selected from optical glass, polymeric optical films; the material of the high-molecular optical film comprises acrylate, epoxy resin, polycarbonate, polystyrene, polyethylene terephthalate, cellulose triacetate or polyimide; preferably, the light transmittance of the transparent light guide layer in the wavelength range of 350-1000nm is more than 90%; preferably, the organic transparent material is selected from a cyclic polyolefin layer or a transparent polyimide layer; preferably, the thickness of the transparent light guide layer (10) is 1-300 μm; the thickness precision of the transparent light guide layer is controlled to be +/-5%; preferably, the cross-sectional shape of the optical collimator is S-shaped, C-shaped, or linear.

6. The optical collimator as claimed in claim 1, wherein the light absorbing layer comprises 30 to 90 parts by weight of a resin material, 0.1 to 70 parts by weight of a light absorbing material and 0.5 to 20 parts by weight of a hard spacer; preferably, the light absorption layer is made of a resin material selected from any one of epoxy resin, silicone resin, acrylic resin, PI resin, polyurethane and PU resin, acrylate, epoxy resin, polycarbonate, polystyrene, polyethylene terephthalate, or polyimide; preferably, the thickness of the light absorbing layer is 1-30 μm; the thickness precision of the light absorption layer is controlled to be +/-5%; preferably, the shape of the hard spacer is selected from the group consisting of spherical, columnar, rod-like, net-like; preferably, the thickness of the hard spacer is 1 μm to 30 μm.

7. The optical collimator of claim 6, wherein a ratio of a thickness of the transparent light guiding layer to a thickness of the light absorbing layer in the collimating unit is 1: 1-10: 1; the ratio of the channel width (W) to the channel depth (L) of the collimated light transmitting channels is in the range of 1: 30-1: 5.

8. a method for preparing an optical collimator is characterized by comprising the following steps:

9. The method of claim 8, further comprising the step of adding a predetermined amount of hard spacers to the coating solution and mixing them uniformly in step S2.

10. An optical imaging device, characterized in that it comprises an optical sensor and an optical collimator according to any one of claims 1-7, which is arranged on the light-sensitive side of the optical sensor.