CN111353478A - Micro-lens array and manufacturing method thereof, biological identification module and electronic equipment thereof - Google Patents
Micro-lens array and manufacturing method thereof, biological identification module and electronic equipment thereof Download PDFInfo
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- CN111353478A CN111353478A CN202010338968.0A CN202010338968A CN111353478A CN 111353478 A CN111353478 A CN 111353478A CN 202010338968 A CN202010338968 A CN 202010338968A CN 111353478 A CN111353478 A CN 111353478A
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
- G06V40/00—Recognition of biometric, human-related or animal-related patterns in image or video data
- G06V40/10—Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
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- G—PHYSICS
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- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
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Abstract
The invention relates to a micro-lens array and a manufacturing method thereof, a biological identification module and electronic equipment thereof, wherein the micro-lens array comprises a transparent substrate, a light absorption layer, a light transmission filling layer and a micro-lens component, the transparent substrate is provided with a first surface and a second surface which are oppositely arranged, and a plurality of through holes which are arrayed, the through holes comprise a first opening part, a second opening part and an inner wall which connects the first opening part and the second opening part, the light absorption layer comprises a first light absorption part, and the first light absorption part is arranged on the inner wall; the light-transmitting filling layer comprises a first light-transmitting filling part, and the first light-transmitting filling part is filled in the through hole provided with the first light-absorbing part; the micro lens assembly comprises a plurality of micro lenses which are arranged in one-to-one correspondence with the through holes, and the micro lens array can shield stray light with a large incident angle through the light absorption layer, so that the consistency of the definition of an image formed after incident light penetrates through the micro lenses is improved, the light condensation efficiency of the micro lenses is improved, and the imaging effect is improved.
Description
Technical Field
The invention relates to the technical field of optical elements, in particular to a micro-lens array and a manufacturing method thereof, a biological identification module and electronic equipment thereof.
Background
The micro lens array is a permutation and combination of a certain number of micro-nano scale spherical or free-form surface lenses, not only has basic functions of focusing, imaging and the like of the traditional lens, but also has the characteristics of small unit size and high integration level, so that the micro lens array can complete the functions which cannot be completed by the traditional optical element and can form a plurality of novel optical systems.
A conventional microlens array is formed by disposing a plurality of microlenses on a substrate. The micro lens with the structure has the phenomenon that flash, double images and mixed color light easily appear when light penetrates through the micro lens, and further the imaging effect is influenced.
Disclosure of Invention
In view of the above, it is desirable to provide a microlens array that can improve the imaging effect.
The present invention provides a microlens array, comprising:
the transparent substrate is provided with a first surface and a second surface which are oppositely arranged, and a plurality of through holes which penetrate through the first surface and the second surface and are arranged in an array mode, each through hole comprises a first opening part, a second opening part and an inner wall which connects the first opening part and the second opening part, the first opening part is located on the first surface, and the second opening part is located on the second surface;
the light absorption layer comprises a first light absorption part, and the first light absorption part is arranged on the inner wall;
the light-transmitting filling layer comprises a first light-transmitting filling part, the shape of the first light-transmitting filling part is matched with that of the through hole provided with the first light-absorbing part, and the first light-transmitting filling part is filled in the through hole provided with the first light-absorbing part;
the micro lens assembly comprises a plurality of micro lenses which are arranged in one-to-one correspondence with the through holes, the micro lenses are arranged on the surface of the first light-transmitting filling part, and the central axes of the micro lenses are coincided with the central axes of the corresponding through holes.
According to the invention, the first light-absorbing part is arranged on the inner wall of the through hole of the transparent substrate, so that parasitic light with a larger incident angle can be shielded, the consistency of the definition of an image formed by the incident light after penetrating through the micro lens is improved, the light-gathering efficiency of the micro lens is improved, and the imaging effect is improved. And stray light with a large incident angle can be effectively relieved from being refracted to the light condensation positions of other micro-lens assemblies, so that crosstalk cannot be generated in sampling among different micro-lens assemblies, and the phenomenon of parallax of formed images is avoided.
In one embodiment, the ratio of the thickness of the transparent substrate to the diameter of the second opening is 10:1 to 20: 1. The inventors have found that, when the ratio of the thickness h of the transparent substrate to the diameter of the second opening is in this range, stray light having a wider incident angle range of incident light can be absorbed, and the microlens imaging effect is better.
In one embodiment, the transparent substrate has a thickness of 100 to 200 μm, and the second opening has a diameter of 10 to 20 μm. Within this range, the microlens imaging effect is better.
In one embodiment, the through hole is cylindrical in shape. The through hole is cylindrical, so that the symmetry is better, and the manufacturing process is simpler.
In one embodiment, the aperture of the through hole gradually increases from the second opening portion to the first opening portion.
In one embodiment, the through hole is in a shape of a step or an inverted truncated cone. When the via shape may be a non-cylindrical stepped via or an inverted truncated circular truncated via.
In one embodiment, the micro lens is provided with a joint surface jointed with the first light-transmitting filling part and the first surface; the projection of the second opening part on the binding surface of the micro lens completely falls on the binding surface, and a gap is formed between the second opening part and the edge of the binding surface. I.e. the through-holes can be completely covered by the micro-lenses.
In one embodiment, the light absorbing layer further includes a second light absorbing portion provided on the first surface and covering a portion of the transparent substrate not covered by the microlens. Therefore, the second light absorption part can shield light which is not emitted to the micro lens to a greater degree, and the formation of an image with lower definition due to the fact that the part of incident light is not focused by the micro lens is avoided. Therefore, the phenomenon that a blurred image is formed in an area between the light-gathering positions of the adjacent micro lenses, namely a miscellaneous area, is avoided, and the influence of the blurred imaging of the miscellaneous area on the whole imaging effect of the micro lens array component is also avoided. The first light absorption part and the second light absorption part share the same action, so that the light condensation efficiency of the micro-lens component can be better improved, and the imaging effect is improved.
In one embodiment, the first light absorption portion has a thickness of 1.5 μm to 5 μm.
In one embodiment, the second light absorption portion has a thickness of 1.5 μm to 5 μm. The range setting not only can realize the requirement of ultra-thinness, but also can effectively play the role of light absorption.
In one embodiment, the light absorbing layer is a titanium layer, a chromium layer, a silicon dioxide layer, a titanium carbide layer, or a silicon carbide layer. The light absorption layers are black light absorption layers with good light absorption.
In one embodiment, the light-transmitting filling layer further includes a second light-transmitting filling portion, the second light-transmitting filling portion is disposed on a surface of the second light-absorbing portion away from the first surface and a surface of the first light-transmitting filling portion, and the microlens covers a surface of the second filling portion on the surface of the first light-transmitting filling portion and a surface of the second light-transmitting filling portion partly on the surface of the second light-absorbing portion.
In one embodiment, the first light-transmitting filling portion and the second light-transmitting filling portion are made of an optically transparent material. The first light-transmitting filling part is made of an optical transparent material and is realized by adopting the existing excellent optical transparent material.
In one embodiment, the thickness of the second light-transmitting filling part is 1.5-5 μm.
In one embodiment, the transparent substrate is made of glass, mica sheet or silicon. The transparent substrate made of the materials is a material with excellent optical performance, and has higher strength and surface effect.
The invention also provides a manufacturing method of the micro-lens array, which comprises the following steps:
providing the transparent substrate;
forming a plurality of blind holes arranged in an array on the first surface of the transparent substrate;
forming a light absorption layer on the inner wall of the blind hole;
filling a light-transmitting filling layer in the blind hole with the light absorption layer;
forming a plurality of micro lenses which are in one-to-one correspondence with the blind holes on the surface of the light-transmitting filling layer away from the light absorption layer;
and thinning the transparent substrate from the second surface to the first surface so that the blind hole penetrates through the transparent substrate to form a through hole.
The method is simple in manufacturing process, and the manufactured micro-lens array can achieve optical collimation and stray light prevention effects.
In one embodiment, a light absorbing layer is further formed on the first surface.
In one embodiment, the light-transmitting filling layer is further formed on the surface of the light-absorbing layer on the first surface.
In one embodiment, the blind holes are formed by a laser or etching process; and/or, the light absorbing layer is formed by an evaporation or sputtering process.
A biological identification module comprises the micro lens array or the micro lens array obtained by the manufacturing method. Above-mentioned biological identification module can shelter from the great miscellaneous light of incident angle through the light-absorbing layer to improve the incident light and see through the uniformity of the definition of the image that forms behind the microlens, improve microlens spotlight efficiency, improve the imaging promptly.
An electronic device comprises the biometric identification module. Above-mentioned electronic equipment can shelter from the great parasitic light of incident angle through the light-absorbing layer to improve the incident light and see through the uniformity of the definition of the image that forms behind the microlens, improve microlens spotlight efficiency, improve the formation of image effect promptly.
Drawings
FIG. 1 is a schematic top view of a microlens array of the present invention;
FIG. 2 is a cross-sectional view of a microlens along the line A-A of the microlens array of the embodiment of FIG. 1;
FIG. 3 is a cross-sectional view of a microlens along the line A-A of another embodiment microlens array of FIG. 1;
FIG. 4 is a bottom view of the microlens array of FIG. 2 or FIG. 3;
FIG. 5 is a cross-sectional view of a microlens along the line A-A of the microlens array of the embodiment of FIG. 1;
FIG. 6 is a flowchart of a method of fabricating the microlens array of FIG. 2 or FIG. 3;
FIG. 7 is a flowchart of the microlens array fabrication of FIG. 2 or FIG. 3;
fig. 8 is a flowchart of the microlens array fabrication of fig. 5.
Detailed Description
To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.
As shown in fig. 1 to 4, the microlens array of one embodiment can be applied to the fields of optoelectronic devices such as digital cameras, mobile phones, and tablet computers. The micro lens array comprises a transparent substrate 100, a light absorption layer, a light transmission filling layer and a micro lens component;
the transparent substrate 100 has a first surface 101 and a second surface 102 which are oppositely arranged, and a plurality of through holes 103 which penetrate through the first surface 101 and the second surface 102 and are arranged in an array;
further, the transparent substrate 100 is made of an optically transparent material, and may be made of a transparent material having a refractive index of about 1.52, such as glass, mica sheet, silicon, and the like, and the transparent substrate 100 made of the above materials is a material with excellent optical properties, and has higher strength and surface effect.
The thickness of the transparent substrate 100 is denoted by h, and in one embodiment, the thickness h of the transparent substrate 100 is 100 μm to 200 μm; in a specific example, the thickness h thereof may be 100 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 180 μm, or 200 μm. The transparent substrate 100 having a thickness within the above range has more suitable strength and surface effect.
The through hole 103 includes a first opening 1031, a second opening 1032, and an inner wall 1033 connecting the first opening 1031 and the second opening 1032, the first opening 1031 is located on the first surface 101, and the second opening 1032 is located on the second surface 102;
in one embodiment, the shape of the through-hole 103 may be different, and as shown in fig. 2, the through-hole 103 may be a single diameter through-hole. That is, the through hole 103 is formed by a plurality of sections having the same aperture, such as a cylindrical through hole; at this time, the diameter of the first opening 1031 is the same as that of the second opening 1032; as shown in fig. 3, the through hole 103 may also be formed to include a plurality of sections or portions having different diameters, and in a preferred embodiment, the diameter of the through hole 103 gradually increases from the second opening 102 to the first opening 101. Such via 103 may be in the shape of a non-cylindrical stepped via or an inverted truncated cone via.
The diameter of the second opening 1032 is denoted by a, and the diameter a of the second opening 1032 is 10 to 20 μm; in a specific example, the diameter a of the second opening 1032 may be 10 μm, 12 μm, 13 μm, 15 μm, 16 μm, 18 μm, or 20 μm.
Generally, incident light impinging on a microlens assembly includes normal light and non-normal light. The light intensity of vertical light is reduced little after the vertical light passes through the micro-lens component, so that the definition of the formed image is higher. And the non-vertical light is refracted when passing through the micro-lens component, so that the light intensity of the non-vertical light is weakened more after passing through the micro-lens component, and the definition of the formed image is lower. When the normal light and the non-normal light exist simultaneously, and the range of the incident angle of the non-normal light when the non-normal light is incident on the micro lens or the transparent substrate is large, the consistency of the definition of an image formed after the incident light penetrates through the micro lens assembly is weak, so that the light condensing efficiency of the micro lens assembly is low, and the imaging effect is influenced.
The light absorption layer is used for absorbing stray light with a large incidence angle entering the micro lens, so that the consistency of the definition of an image formed after the incident light penetrates through the micro lens is improved, the light condensation efficiency of the micro lens is improved, and the imaging effect is improved.
It should be noted that the vertical light refers to light perpendicular to the incident surface of the microlens, and is not vertical light otherwise.
The light absorbing layer is disposed in one-to-one correspondence with the through holes 103, and specifically, the light absorbing layer includes a first light absorbing portion 201, where the first light absorbing portion 201 is disposed on an inner wall 1033 of the through hole 103 and covers the entire inner wall 1033.
Further, when the via 103 may be shaped as a non-cylindrical stepped via or an inverted truncated circular truncated via.
Furthermore, the inventors have found that the ratio of the thickness h of the transparent substrate 100 to the diameter a of the second opening 102 affects the light absorption effect, and when h/a is 10:1 to 20:1, the incident light with a larger angle enters the microlens assembly and is refracted to be effectively absorbed by the light absorption layer 200. When h/a is less than 10:1, stray light cannot be absorbed to cause interference, and when h/a is more than 20:1, the amount of light entering is insufficient. In specific examples, h/a may be 10:1, 12:1, 14:1, 15:1, 18:1, or 20: 1.
The thickness of the first light absorption portion 201 is 1.5 μm to 5 μm. For example, it may be 1.5. mu.m, 2. mu.m, 2.5. mu.m, 3. mu.m, 4. mu.m or 5. mu.m. Due to the arrangement of the range, the requirement of ultra-thinness can be met, and meanwhile, the shading effect can be effectively achieved.
Optionally, the first light absorbing portion 201 is a titanium layer, a chromium layer, a silicon dioxide layer, a titanium carbide layer, or a silicon carbide layer. The material can effectively absorb light; the light absorbing layer 200 may be provided by a process commonly used in the art, for example, the light absorbing layer 200 may be provided on the inner wall 1033 of the through hole 103 by coating a photoresist. The light absorption layer formed by the process is smoother and more uniform.
Of course, it is understood that in another possible embodiment, the light absorbing layer 200 is not limited to a titanium layer, a chromium layer, a silicon dioxide layer, a titanium carbide layer, or a silicon carbide layer, but may be a black light shielding layer such as an epoxy resin.
The light-transmitting filling layer and the light-absorbing layer are arranged in a one-to-one correspondence manner, specifically, the light-transmitting filling layer comprises a first light-transmitting filling part 301, the shape of the first light-transmitting filling part 301 is matched with that of the through hole 103 provided with the first light-absorbing part 201, and the first light-transmitting filling part 301 is filled in the through hole 103 provided with the first light-absorbing part 201.
The light-transmitting filling layer is an optically transparent filling layer for filling the through hole 103.
The first light-transmitting filling portion 301 is made of an optically transparent material, and is implemented by using an existing excellent optically transparent material, specifically, a UV adhesive material.
Micro-lens components for focusing, imaging, etc.; the micro lens assembly includes a plurality of micro lenses 400 disposed in one-to-one correspondence with the through holes 103, that is, the plurality of micro lenses 400 are arranged in an array on the first surface 101 of the transparent substrate 100; the micro lens 400 covers the surface of the first light-transmitting filling part 301 and the first surface 101;
the microlens 400 has an attaching surface 401 attached to both the first light-transmitting filling portion 301 and the first surface 101; in a direction perpendicular to the first surface 101, the central axis of the microlens 400 coincides with the central axis of the corresponding through hole 103, as indicated by the dashed line b in fig. 2. The projection of the second opening 1032 onto the bonding surface 401 of the microlens 400 completely falls on the bonding surface 401, and is spaced from the edge of the bonding surface 401, that is, the through holes 103 are all completely covered by the microlens 400.
Specifically, the microlens 400 may be a polygonal microlens, and further, may be a regular hexagonal microlens, a regular pentagonal microlens, a regular quadrilateral microlens, or a regular triangular microlens.
In this embodiment, the microlens 400 is a spherical microlens. The diameter of the second opening 1032 is smaller than the diameter of the microlens 400, so that the projection of the through hole 103 on the bonding surface 401 of the microlens 400 completely falls on the bonding surface 401 with a space from the edge of the bonding surface 401.
Above-mentioned microlens array can shelter from the great parasitic light of incident angle through the light-absorbing layer to improve the incident light and see through the uniformity of the definition of the image that forms behind the microlens subassembly, improve microlens subassembly spotlight efficiency, improve the formation of image effect promptly.
Specifically, referring to fig. 2 and 3, L1 is vertical light, and L2 and L3 are both non-vertical light. The incident angle of L2 is A, and the incident angle of L3 is B. Obviously, the size of the incident angle B is larger than that of the incident angle a, i.e., the incident angle of L3 is larger than that of L2. In other words, the closer to the edge of the microlens 400, the larger the incident angle of the incident light. Accordingly, the closer to the edge of the microlens, the greater the refractive loss of the incident light after it enters the microlens. In this embodiment, L3 is the light with the largest incident angle that can enter the microlens 400, that is, the first light absorbing portion 201 can absorb stray light with an incident angle greater than B, that is, absorb light with lower definition after incident imaging, and the definition of incident light incident imaging with an incident angle less than B is greater than or equal to the definition of incident imaging of the incident light L3, so as to improve the consistency of the definition of the image formed by the microlens 400, improve the light condensing efficiency of the microlens, that is, improve the molding effect.
In this embodiment, the first light absorption portion 201 absorbs the parasitic light with a large incident angle, so that the parasitic light with a large incident angle can be effectively alleviated from being refracted to the light condensation positions of other micro-lens assemblies, and further, the sampling between different micro-lens assemblies cannot generate crosstalk, thereby avoiding the parallax phenomenon of the formed image.
As shown in fig. 5 to 6, the microlens arrays according to the two embodiments are different from the microlens array according to the one embodiment in that:
the light absorption layer comprises a first light absorption part 201 and a second light absorption part 202, wherein the first light absorption part 201 is arranged on the inner wall 1033 of the through hole 103 and covers the whole inner wall 1033, and the second light absorption part 202 is arranged on the first surface 101; and covers the portion of the transparent substrate 100 not covered by the microlenses 400; further, the first light absorbing portion 201 is provided integrally with the second light absorbing portion 202, that is, the light absorbing layer 200 is provided extending from the inner wall 1033 of the through hole to the first surface 101, by providing the light absorbing layer 200 throughout the inner wall 1033 and the first surface 101; the first light absorption portion 201 and the second light absorption portion 202 work together to improve the light condensation efficiency of the micro-lens assembly and improve the imaging effect.
The thicknesses of the first light absorbing portion 201 and the second light absorbing portion 202 are 1.5 μm to 5 μm. For example, it may be 1.5. mu.m, 2. mu.m, 2.5. mu.m, 3. mu.m, 4. mu.m or 5. mu.m. Due to the arrangement of the range, the requirement of ultra-thinness can be met, and meanwhile, the shading effect can be effectively achieved.
It should be noted that the thickness of the first light absorbing portion 201 may be the same as or different from the thickness of the second light absorbing portion 202, and in order to simplify the manufacturing process, the thickness of the first light absorbing portion 201 is generally the same as that of the second light absorbing portion 202.
Optionally, the first light absorbing portion 201 and the second light absorbing portion 202 are a titanium layer, a chromium layer, a silicon dioxide layer, a titanium carbide layer, or a silicon carbide layer. The material can effectively absorb light; the light absorbing layer 200 may be disposed by a process commonly used in the art, for example, the light absorbing layer 200 may be disposed on the inner wall 1033 of the through hole 103 and the first surface 101 of the transparent substrate 100 by evaporation or coating of a photoresist. The light absorbing layer 200 formed by the process is smoother and more uniform.
The light-transmitting filling layer is arranged in one-to-one correspondence with the light-absorbing layer 200, specifically, the light-transmitting filling layer comprises a first light-transmitting filling part 301 and a second light-transmitting filling part 302, the second light-transmitting filling part 302 is arranged on the surface of the second light-absorbing part 202 far away from the first surface 101, and the first light-transmitting filling part 302 far away from the first light-absorbing part; more specifically, the first light-transmissive filling portion 301 is provided integrally with the second light-transmissive filling portion 302, that is, the first light-transmissive filling portion 301 is provided extending from the surface of the first light-absorbing portion 201 of the through-hole to the surface of the second light-absorbing portion 202. Of course, in some embodiments, the second light transmissive filling layer 302 may not be provided, i.e., the microlenses 400 may be provided directly on the surface where the second light absorbing portion 202 and the first light transmissive filling portion 301 are provided.
The first light-transmitting filling portion 301 and the second light-transmitting filling portion 302 are made of an optically transparent material.
The thickness of the second light-transmitting filling portion 302 is 1.5 to 5 μm, and the second light-transmitting filling portion 302 having the thickness within the above range has more appropriate strength and surface effect.
The micro lens assembly includes a plurality of micro lenses 400 disposed in one-to-one correspondence with the through holes 103, that is, the plurality of micro lenses 400 are arranged in an array on the first surface 101 of the transparent substrate 100; the microlens 400 covers the surface of the second filling portion 302 on the surface of the first light-transmitting filling portion 301 and partially covers the surface of the second light-transmitting filling portion 302 on the surface of the second light-absorbing portion 202;
it can be understood that the microlens 400 partially covers the surface of the second light-transmitting filling portion 302 on the surface of the second light-absorbing portion 202, that is, a part of the second light-transmitting filling portion 302 and the second light-absorbing portion 202 are not completely covered by the microlens 400, so that the second light-absorbing portion 202 can largely block the light which is not incident on the microlens 400, and thus the formation of a low-definition image due to the fact that the part of the incident light is not focused by the microlens 400 is avoided. Therefore, the phenomenon that a blurred image is formed in an area between the light-gathering positions of the adjacent micro lenses, namely a miscellaneous area, is avoided, and the influence of the blurred imaging of the miscellaneous area on the whole imaging effect of the micro lens array component is also avoided.
The microlens 400 has a bonding surface 401 bonded to the light-transmitting filling layer 300; in a direction perpendicular to the first surface 101, the central axis of the microlens 400 coincides with the central axis of the corresponding through hole 103, as indicated with reference to the dashed line b in fig. 5. The projection of the second opening 1032 onto the bonding surface 401 of the microlens 400 completely falls on the bonding surface 401, and is spaced from the edge of the bonding surface 401, that is, the through holes 103 are all completely covered by the microlens 400.
The second light absorption portion 202 can further absorb stray light with a large incident angle injected into the partially light transmissive filling layer 300. Thereby further improving the consistency of the definition of the image formed after the incident light penetrates through the micro lens 400, and improving the light condensing efficiency of the micro lens 400, i.e. improving the imaging effect. That is, the first light absorption portion and the second light absorption portion act together, so that the light condensing efficiency of the microlens 400 can be improved better, and the imaging effect can be improved.
With the light absorbing layer of the present embodiment, the first light absorbing portion 201 can absorb the stray light with a large incident angle, which is injected into the first light transmitting filling portion 301, to a large extent; while the second light-absorbing portion 202 may primarily largely block stray light passing through the second light-transmissive filling portion 302 between the adjacent microlenses 130. Therefore, the phenomenon that the miscellaneous region forms a fuzzy image is avoided, and the influence of the fuzzy imaging of the miscellaneous region on the whole imaging effect of the micro-lens component is also avoided. Therefore, the first light absorption portion 201 and the first light absorption portion 202 work together to improve the light gathering efficiency of the microlens 400 and improve the imaging effect.
Specifically, referring to fig. 5, L4 enters the micro lens and then enters the second light absorption portion 202 to be absorbed by the second light absorption portion 202. The incident angle of L4 is smaller than the incident angle of the incident light L3 having the smallest incident angle that the first light absorbing portion 201 can absorb. Incident light with an incident angle larger than L3 is absorbed by the first light absorbing part 201 and the second light absorbing part 202 in sequence, incident light with an incident angle larger than L4 is absorbed by the first light absorbing part 202, and the minimum incident angle of the absorbed incident light is reduced by the cooperation of the first light absorbing part 201 and the second light absorbing part 202. Thus, the uniformity of the sharpness of the image formed by the microlens 400 is further improved, and the light-gathering efficiency of the microlens, that is, the molding effect is improved.
The micro lens array has at least the following advantages:
1) through setting up first light-absorbing part 201 at the inner wall of through-hole 103, the non-perpendicular light that gets into microlens 400 inside through the refraction can be absorbed by first light-absorbing part 201, and finally only perpendicular light passes through from microlens 400, can realize promoting the purpose of collimation effect to improve the uniformity of the definition of the image that the incident light formed after permeating microlens subassembly, improve microlens subassembly spotlight efficiency, improve the imaging effect promptly. And stray light with a large incident angle can be effectively relieved from being refracted to the light condensation positions of other micro-lens assemblies, so that crosstalk cannot be generated in sampling among different micro-lens assemblies, and the phenomenon of parallax of formed images is avoided.
2) In the manufacturing process of the micro lens, for example, a micro lens array is formed on a transparent substrate through an imprinting process, the method adopts a separation type manufacturing method, when a light-transmitting hole of a light-absorbing layer is manufactured, the surface of the transparent substrate is exposed through a photoetching process and developed to form the light-absorbing layer, and the micro lens is formed through an imprinting or reflow soldering process, because the precision of the exposure process has deviation, the light-transmitting hole of the light-absorbing layer arranged on the surface of the transparent substrate and the center of the micro lens cannot be completely aligned in a one-to-one mode, the problem of interference of stray light with large angles is caused, the manufacturing process is complex, and the performance of the obtained micro lens is not ideal.
3) When the ratio of the thickness h of the transparent substrate 100 to the diameter a of the second opening 102 is 10:1 to 20:1, the incident light with a larger angle enters the micro-lens assembly and can be effectively absorbed by the light absorbing layer 200 after being refracted. When h/a is less than 10:1, stray light interference exists, and when h/a is more than 20:1, the light entering amount is insufficient;
4) with the light absorbing layer of the present embodiment, the first light absorbing portion 201 can absorb the stray light with a large incident angle, which is injected into the first light transmitting filling portion 301, to a large extent; while the second light-absorbing portion 202 may primarily largely block light passing through the second light-transmissive filling portion 302 between the adjacent microlenses 130. Therefore, the phenomenon that the miscellaneous region forms a fuzzy image is avoided, and the influence of the fuzzy imaging of the miscellaneous region on the whole imaging effect of the micro-lens component is also avoided. Therefore, the first light absorption portion 201 and the first light absorption portion 202 work together to improve the light condensation efficiency of the microlens 400 and improve the imaging effect. And the first light absorption part 201 and the second light absorption part 202 act together, the minimum incident angle of the absorbable incident light is reduced, so that the consistency of the definition of an image formed by the micro lens 400 is further improved, the light condensation efficiency of the micro lens is improved, namely, the forming effect is improved, the effect of absorbing the large-angle stray light at multiple angles is realized, the light condensation efficiency of the micro lens can be better improved, and the imaging effect is improved.
As shown in fig. 6 to 8, the method for manufacturing a microlens array according to the above embodiment includes the steps of:
step S110: providing a transparent substrate 100;
wherein, the transparent substrate 100 has a first surface 101 and a second surface 102 which are oppositely arranged; the transparent substrate 100 may employ a glass or silicon substrate.
Step S120: forming a plurality of blind holes 104 arranged in an array on a first surface 101 of a transparent substrate 100;
specifically, the blind holes 104 are formed by a laser or etching process; the depth H of the blind hole 104 is 100-200 μm;
step S130: forming a light absorbing layer on the inner wall of the blind hole 104;
specifically, the light absorbing layer is a first light absorbing portion 201; as shown in fig. 8, further, in order to improve the image forming effect, step S130 may also form a second light absorbing portion 202 of the light absorbing layer for each of the first surfaces 101; the thickness of the light absorption layer 200 is 1.5-5 μm;
light absorbing layers with certain optical characteristics are deposited on the inner wall of the blind hole 104 and the first surface 101 by using processes such as evaporation or sputtering, and the light absorbing layers can be made of titanium, chromium, silicon dioxide, titanium carbide or silicon carbide, and can also be made of epoxy resin.
Step S140: filling a light-transmitting filling layer in the blind hole 104 formed with the light absorbing layer;
wherein the light-transmitting filling layer is a first light-transmitting filling portion 301; as shown in fig. 8, further, in step S140, a second light-transmitting filling portion 302 of the light-transmitting filling layer is formed on the surface of the light-absorbing layer 200 on the first surface 101 and the surface of the light-transmitting filling layer 300 filled in the blind hole 104;
specifically, the light-transmitting filling layer 300 is formed on the surface of the light-absorbing layer 200 by a coating process, and the blind via 104 is filled by a filling process to form the light-transmitting filling layer 300, wherein the filling process is performed by precision coating or other processes, and of course, other processes known in the art may be used to fill the light-transmitting filling layer 300 into the blind via 104.
Step S150: forming a plurality of micro lenses corresponding to the blind holes 104 one by one on the surface of the light-transmitting filling layer 300 away from the light-absorbing layer 200;
in particular, the microlenses are realized by an embossing process.
Step S160: the transparent substrate 100 is thinned from the second surface 102 to the first surface 101, and the blind via 104 penetrates through the transparent substrate 100 to form the through hole 103.
The light absorbing layer 200 at the bottom of the blind via 104 is removed by grinding for thinning to form a through hole 103.
The method is simple in manufacturing process, and the manufactured micro-lens array can achieve optical collimation and stray light prevention effects.
The biological identification module comprises the micro lens array or the micro lens array manufactured by the method. Above-mentioned biological identification module can shelter from the great miscellaneous light of incident angle through the light-absorbing layer to improve the incident light and see through the uniformity of the definition of the image that forms behind the microlens, improve microlens spotlight efficiency, improve the imaging promptly.
Further provided is an electronic device comprising a biometric identification module. Above-mentioned electronic equipment can shelter from the great parasitic light of incident angle through the light-absorbing layer to improve the incident light and see through the uniformity of the definition of the image that forms behind the microlens, improve microlens spotlight efficiency, improve the formation of image effect promptly.
Specifically, the electronic device may be a mobile phone, a camera, a tablet computer, or the like.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (21)
1. A microlens array, comprising:
the transparent substrate is provided with a first surface and a second surface which are oppositely arranged, and a plurality of through holes which penetrate through the first surface and the second surface and are arranged in an array mode, the through holes comprise a first opening part, a second opening part and an inner wall which connects the first opening part and the second opening part, the first opening part is located on the first surface, and the second opening part is located on the second surface;
the light absorption layer comprises a first light absorption part, and the first light absorption part is arranged on the inner wall;
the light-transmitting filling layer comprises a first light-transmitting filling part, the shape of the first light-transmitting filling part is matched with that of the through hole provided with the first light-absorbing part, and the first light-transmitting filling part is filled in the through hole provided with the first light-absorbing part;
the micro lens assembly comprises a plurality of micro lenses which are arranged in one-to-one correspondence with the through holes, the micro lenses are arranged on the surface of the first light-transmitting filling part, and the central axes of the micro lenses are coincided with the central axes of the corresponding through holes.
2. The microlens array as claimed in claim 1, wherein a ratio of a thickness of the transparent substrate to a diameter of the second opening portion is 10:1 to 20: 1.
3. The microlens array as claimed in claim 1, wherein the transparent substrate has a thickness of 100 to 200 μm, and the second opening has a diameter of 10 to 20 μm.
4. The microlens array of claim 1, wherein the through-holes are cylindrical in shape.
5. The microlens array as claimed in claim 1, wherein the aperture of the through-hole gradually increases from the second opening portion to the first opening portion.
6. The microlens array of claim 5, wherein the via hole is stepped or inverted truncated-cone-shaped.
7. The microlens array of any one of claims 1-6 wherein the microlenses have abutting faces abutting both the first light-transmissive filling portion and the first surface; the projection of the second opening part on the binding surface of the micro lens completely falls on the binding surface, and a gap is formed between the second opening part and the edge of the binding surface.
8. The microlens array as in any one of claims 1-6, wherein the light absorbing layer further comprises a second light absorbing portion disposed on the first surface and covering a portion of the transparent substrate not covered by the microlenses.
9. The microlens array as in any one of claims 1 to 6, wherein the first light absorbing portion has a thickness of 1.5 μm to 5 μm.
10. The microlens array of claim 8, wherein the second light absorbing portion has a thickness of 1.5 μm to 5 μm.
11. The microlens array as in any one of claims 1 to 6, wherein the light absorbing layer is a titanium layer, a chromium layer, a silicon dioxide layer, a titanium carbide layer or a silicon carbide layer.
12. The microlens array as claimed in claim 8, wherein the light transmissive filling layer further includes a second light transmissive filling portion, the second light transmissive filling portion is disposed on a surface of the second light absorbing portion away from the first surface and a surface of the first light transmissive filling portion, and the microlenses are disposed on a surface of the second filling portion overlying the surface of the first light transmissive filling portion and a surface of the second light transmissive filling portion overlying the surface of the second light absorbing portion.
13. The microlens array as claimed in claim 12, wherein the first and second light-transmissive filling portions are made of an optically transparent material.
14. The microlens array as in any of claims 12-13, wherein the second light-transmissive filling portion has a thickness of 1.5 to 5 μm.
15. The microlens array as in any one of claims 1-6, wherein the transparent substrate is made of glass, mica sheet or silicon.
16. A method for fabricating a microlens array as claimed in any one of claims 1 to 15, comprising the steps of:
providing the transparent substrate;
forming a plurality of blind holes arranged in an array on the first surface of the transparent substrate;
forming a light absorption layer on the inner wall of the blind hole;
filling a light-transmitting filling layer in the blind hole with the light absorption layer;
forming a plurality of micro lenses which are in one-to-one correspondence with the blind holes on the surface of the light-transmitting filling layer away from the light absorption layer;
and thinning the transparent substrate from the second surface to the first surface so that the blind hole penetrates through the transparent substrate to form a through hole.
17. The method of claim 16, further comprising forming a light absorbing layer on the first surface.
18. The manufacturing method according to claim 16 or 17, wherein the light-transmitting filling layer is further formed on the surface of the light-absorbing layer on the first surface.
19. The method of manufacturing of claim 17, wherein the blind holes are formed by a laser or etching process; and/or, the light absorbing layer is formed by an evaporation or sputtering process.
20. A biometric module comprising the microlens array of any one of claims 1-15.
21. An electronic device comprising the biometric module of claim 20.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010338968.0A CN111353478A (en) | 2020-04-26 | 2020-04-26 | Micro-lens array and manufacturing method thereof, biological identification module and electronic equipment thereof |
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| CN202010338968.0A CN111353478A (en) | 2020-04-26 | 2020-04-26 | Micro-lens array and manufacturing method thereof, biological identification module and electronic equipment thereof |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112084996A (en) * | 2020-09-21 | 2020-12-15 | 上海悠睿光学有限公司 | Fingerprint recognition device under screen and electronic equipment |
| CN112327391A (en) * | 2020-10-20 | 2021-02-05 | 上海悠睿光学有限公司 | Preparation method of micro-lens array, micro-lens array and under-screen fingerprint module |
-
2020
- 2020-04-26 CN CN202010338968.0A patent/CN111353478A/en not_active Withdrawn
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112084996A (en) * | 2020-09-21 | 2020-12-15 | 上海悠睿光学有限公司 | Fingerprint recognition device under screen and electronic equipment |
| CN112327391A (en) * | 2020-10-20 | 2021-02-05 | 上海悠睿光学有限公司 | Preparation method of micro-lens array, micro-lens array and under-screen fingerprint module |
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Address after: 330096 No.699 Tianxiang North Avenue, Nanchang hi tech Industrial Development Zone, Nanchang City, Jiangxi Province Applicant after: Jiangxi OMS Microelectronics Co.,Ltd. Address before: 330200 East of College Sixth Road and South of Tianxiang Avenue, Nanchang High-tech Industrial Development Zone, Nanchang City, Jiangxi Province Applicant before: OFilm Microelectronics Technology Co.,Ltd. |
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