TWI727550B - Optical identification module - Google Patents

Abstract

An optical identification module including a semiconductor substrate, a plurality of shielding layers and a micro lens is provided. The semiconductor substrate has at least one sensing region. The shielding layers are located above the semiconductor substrate. Each of the shielding layers has at least one opening. Openings of the shielding layers form at least one light penetrating hole to cause external light to be obliquely transmitted to the sensing region through the light penetrating hole. The orthographic projection position of each opening on the semiconductor substrate and the sensing region have a shift parallel to the semiconductor substrate. The micro lens is disposed on an opening of a shielding layer furthest from the semiconductor substrate among the shielding layers to obliquely guide the external light to the sensing region.

Description

Optical recognition module

The present invention relates to an optical module, and particularly relates to an optical identification module.

With the vigorous development of the Internet of Things technology, the application and demand of biometrics technology is expanding rapidly. At present, the common biometric identification technologies on the market mainly use optical, capacitive, or ultrasonic methods to identify biometric features such as fingerprints, palm prints, vein distribution, iris, retina, or facial features, so as to achieve the purpose of identification or authentication. Compared with the recognition module that recognizes biological characteristics by capacitive or ultrasonic methods, the optical recognition module that recognizes biological characteristics optically receives the light reflected by the object to be measured through the sensing area of the image sensor to perform biological The feature recognition therefore has the advantages of high durability and low cost. However, the light beam reflected by the object to be measured is easily scattered to the sensing area, resulting in poor image quality and affecting the recognition result. In addition, a large part of the light emitted by the detection light source (usually the light-emitting pixels of the organic light-emitting diode panel) of the under-screen optical recognition module will illuminate directly below, so that the sensing area directly below the pixel is large. Receiving this light that has nothing to do with fingerprints results in larger noise, which in turn affects the recognition result.

The invention provides an optical identification module, which has good identification capabilities.

The optical identification module of the present invention includes a semiconductor substrate, a plurality of shielding layers and microlenses. The semiconductor substrate has at least one sensing area. The shielding layers are arranged above the semiconductor substrate, wherein each shielding layer has at least one opening, and the plurality of openings of the shielding layers form at least one light through hole, so that external light is obliquely transmitted to the at least one through the at least one light through hole. Sensing area. The orthographic projection position of each opening on the semiconductor substrate and the at least one sensing area have a displacement parallel to the semiconductor substrate. The micro lens is arranged on the opening of the shielding layer farthest from the semiconductor substrate among the shielding layers, so as to obliquely guide external light to the at least one sensing area through the at least one light through hole.

In an embodiment of the present invention, the microlens obliquely guides the oblique light reflected from the fingerprint ridge line of the finger to the at least one sensing area, and guides the light reflected by the non-fingerprint ridge line to the at least one sensing area. One outside the sensing area.

In an embodiment of the present invention, the orthographic projections of the plurality of openings of the plurality of shielding layers on the semiconductor substrate are sequentially arranged along an arrangement direction, and the arrangement direction is parallel to the surface of the semiconductor substrate.

In an embodiment of the present invention, there is an included angle between the extending direction of the light through hole and the semiconductor substrate, and the included angle is not equal to 90 degrees.

In an embodiment of the present invention, the average tangent slope of one side of the microlens is greater than the average tangent slope of the other side.

In an embodiment of the present invention, the microlenses are mirror-symmetrical.

In an embodiment of the present invention, the orthographic projection of the microlens on the semiconductor substrate overlaps with at least one of the plurality of shielding layers.

In an embodiment of the present invention, at least one sensing area is a plurality of sensing areas, and the orthographic projection of the center of the microlens on the semiconductor substrate is located between the sensing areas.

In an embodiment of the present invention, the material of the multiple shielding layers is metal.

In an embodiment of the present invention, the multiple shielding layers are formed by a metal interconnection of the integrated circuit.

In an embodiment of the present invention, the optical identification module further includes a reflective layer disposed on the top surface of the semiconductor substrate, the reflective layer has at least one pinhole, an orthographic projection of the pinhole on the semiconductor substrate and at least one sensing area overlapping.

In an embodiment of the present invention, the pinhole of the reflective layer and the orthographic projection of the opening of the shielding layer closest to the semiconductor substrate among the plurality of shielding layers on the semiconductor substrate overlap with each other.

In an embodiment of the present invention, the size of the pinhole of the reflective layer is smaller than the size of the sensing area.

In an embodiment of the present invention, the above-mentioned optical identification module further includes a plurality of dielectric layers, and each of the dielectric layers is located between two of the shielding layers.

Based on the above, in the optical identification module of the embodiment of the present invention, a plurality of shielding layers and microlenses are used to obliquely guide external light to the sensing area, so as to effectively improve optical interference (crosstalk) and achieve optical noise reduction and Improving the image resolution can also prevent the strong light emitted by the detection light source from affecting the recognition result. Therefore, the optical identification module of the embodiment of the present invention can have good identification capabilities.

In order to make the above-mentioned features and advantages of the present invention more comprehensible, the following specific embodiments are described in detail in conjunction with the accompanying drawings.

In the drawings, each drawing shows the general characteristics of the methods, structures, and/or materials used in a specific exemplary embodiment. However, the drawings are not limited to the structures or features of the following embodiments, and these drawings should not be construed as defining or limiting the scope or properties covered by these exemplary embodiments. For example, for clarity, the relative thickness and position of each layer, region, and/or structure may be reduced or enlarged.

The use of similar or identical element symbols in the various drawings tends to indicate the existence of similar or identical elements or features. Similar component symbols in the drawings indicate similar components and will not be described in detail.

The optical identification module listed in the following embodiments is suitable for capturing the biological characteristics of the test object. The test object can be a finger or a palm. Correspondingly, the biological characteristics can be fingerprints, veins or palm prints, but not limited to this.

FIG. 1 is a schematic cross-sectional view of an optical identification module according to an embodiment of the present invention. Please refer to FIG. 1, the optical identification module 100 of this embodiment includes a semiconductor substrate 110, a plurality of shielding layers 120, and a microlens L1.

The semiconductor substrate 110 has at least one sensing area R. The at least one sensing area R is a light-receiving area in the semiconductor substrate 110 and is suitable for receiving light reflected by an object to be measured (such as a finger) (ie, external light IL, It carries biometric information). For example, a sensing region R can be a pixel of a charge coupled device (CCD), a complementary metal-oxide semiconductor (CMOS) or other appropriate type of image sensor Or several pixels. In this embodiment, the semiconductor substrate 110 has sensing regions R arranged in a two-dimensional array (for example, pixels arranged in an array).

These shielding layers 120 are disposed on the semiconductor substrate 110. Furthermore, each of the shielding layers 120 has at least one opening OP, and the plurality of openings OP of the shielding layers 120 form at least one light through hole TH, so that the external light IL is obliquely transmitted to the at least one through the at least one light through hole TH. A sensing area R, as shown in FIG. 1, the light through hole TH can guide a small part of the outside light that passes directly below and most of the oblique light from the outside. However, in other embodiments, both can also be guided obliquely. The front projection position of each opening OP on the semiconductor substrate 110 and the at least one sensing region R have a displacement parallel to the semiconductor substrate 110, thereby improving optical interference, achieving optical noise reduction, and improving image resolution. It can also prevent the strong light emitted by the detection light source from affecting the recognition result. On the other hand, in this embodiment, the shielding layers 120 are formed by a metal interconnection of the optical identification module 100. In other words, in this embodiment, the material of the shielding layer 120 is metal (for example, metal such as copper, tungsten, or aluminum), but the present invention is not limited to this. In another embodiment, the shielding layers 120 can also be formed by other structures (such as black photoresist) in the optical identification module 100, and the present invention is not limited thereto.

The microlens L1 is disposed on the opening OP of the shielding layer 120 (that is, the uppermost shielding layer 120 in FIG. 1) of the shielding layers 120 farthest from the semiconductor substrate 110, so as to pass external light IL through at least one light. The hole TH obliquely guides to at least one sensing area R. As shown in FIG. 1, it can guide a small part of the light transmitted directly below and most of the oblique light. However, in other embodiments, both can be guided obliquely. To light. In this way, the at least one sensing area R can read and recognize the image information carried by the external light.

As shown in FIG. 1, in this embodiment, the optical identification module 100 further includes a plurality of dielectric layers DL, and each dielectric layer DL is located between two adjacent shielding layers 120 or covering the shielding layer 120.

As shown in FIG. 1, in this embodiment, the orthographic projections of the openings OP of the shielding layer 120 on the semiconductor substrate 110 are sequentially arranged along an arrangement direction D1 (the horizontal direction in FIG. 1), and the arrangement direction D1 Parallel to the surface of the semiconductor substrate 110, these openings OP can form at least one light through hole TH. Thus, in this embodiment, the extending direction of the at least one optical through hole TH has an included angle with the semiconductor substrate 110, and the included angle is not equal to 90 degrees. In this way, the external light IL can be obliquely transmitted to the at least one sensing area R through the at least one light through hole TH, thereby improving optical interference, achieving optical noise reduction, and improving image resolution, and also avoiding detection of the light source. The strong light transmitted directly below affects the recognition result.

In this embodiment, the average tangent slope of one side of the microlens L1 is greater than the average tangent slope of the other side (for example, the left side of the microlens L1 in Figure 1 is steeper, and the right side is more gentle), so as to converge the beam more efficiently and guide it obliquely The external light IL reaches the at least one sensing area R, so that the at least one sensing area R can read and more clearly recognize the image information in the external light.

2 is a schematic cross-sectional view of an electronic device according to an embodiment of the invention. Please refer to FIG. 2, the electronic device ED of this embodiment includes an optical identification module 100 as shown in FIG. 1, a cover glass CG, a substrate DP of a display panel, and an organic light-emitting diode 50 on the substrate DP. . As shown in FIG. 2 (please refer to FIG. 1 for components included in the optical identification module 100), in this embodiment, the light IL reflected by the fingerprint ridge FP of the finger is an oblique light inclined with respect to the semiconductor substrate 110 IL, the microlens L1 obliquely guides the light IL (oblique light) reflected from the fingerprint ridge line FP of the finger to the at least one sensing area R of the optical identification module 100, and the light NIL reflected by the non-fingerprint ridge line is obliquely guided Guided to the outside of at least one sensing area R. In this embodiment, since the light emitted by the detection light source (such as a Lambertian light source) has high directivity, most of the noise from the detection light source is incident at an angle of 30 degrees and comes from the object under test. The reflected light IL is mostly incident obliquely. Therefore, in an embodiment of the present invention, the light IL (oblique light) received by the microlens L1 enters at least one sensing area R, and the light that directly generates noise (that is, the light directly coming from the organic light-emitting diode 50 instead of the reflection from the finger) Light) is deflected out of the sensing area R.

3 is a schematic cross-sectional view of an optical identification module according to another embodiment of the invention. Please refer to FIG. 3, the optical identification module 200 of this embodiment is similar to the optical identification module 100 in FIG. 1, and the main differences between the two are as follows. In this embodiment, the optical identification module 200 may further include a reflective layer RL1 disposed on the top surface of the semiconductor substrate 110 and located between the sensing region R and the shielding layer 120. The reflective layer RL1 has at least one pinhole PH, and the orthographic projection of the at least one pinhole PH on the semiconductor substrate 110 overlaps with at least one sensing region R to further improve optical interference, achieve optical noise reduction, and improve image resolution.

In this embodiment, at least one pinhole PH of the reflective layer RL1 overlaps with the orthographic projection of the opening OP of the shielding layer 120 closest to the semiconductor substrate 110 among the shielding layers 120 on the semiconductor substrate 110. In addition, the size of the pinhole PH is smaller than the size of the sensing area R to effectively suppress optical interference.

4A is a schematic cross-sectional view of an optical identification module according to another embodiment of the present invention, and FIG. 4B is a schematic top view of an optical identification module according to still another embodiment of the present invention. Please refer to FIG. 4A first. The optical identification module 300 of this embodiment is similar to the optical identification module 200 in FIG. 3, and the main differences between the two are as follows. Please refer to FIG. 4A. In this embodiment, the microlens L2 is mirror-symmetrical. In addition, the projection of the microlens L2 on the semiconductor substrate 110 overlaps with at least one of the plurality of shielding layers 120A, so as to block noise and strong light transmitted directly below from the detection light source. Furthermore, in this embodiment, at least one sensing region R is a plurality of sensing regions R, for example, two sensing regions R shown in FIG. 4A share a microlens L2, which is closest to the shielding of the semiconductor substrate 110 The layer 120A has a plurality of openings OP (for example, the two openings in FIG. 4A), and respectively forms a plurality of optical through holes TH (for example, the two optical through holes TH in FIG. 4A) with the plurality of openings OP on the shielding layer 120A. ). The reflective layer RL2 has a plurality of pinholes PH. The orthographic projections of the pinholes PH on the semiconductor substrate 110 overlap the sensing regions R, and the orthographic projections of the center of the microlens L2 on the semiconductor substrate 110 are located in these sensing regions. Between R, in this embodiment, the arrangement relationship between the microlens L2 and these sensing regions R is one-to-two. However, in another embodiment, the number of sensing regions R corresponding to one microlens L2 can be changed as required, and is not limited to the two shown in FIG. 4A. Please refer to the optical identification module 300 shown in FIG. 4B. In the top view schematic diagram, the number of sensing regions R corresponding to a microlens L2 can be, for example, four, that is, the relationship between the microlens L2 and these sensors R is one to four, and the center of the microlens L2 is on the semiconductor The orthographic projection on the substrate 110 is located between the four sensing regions R. In addition, in this embodiment, although the optical identification module 300 is provided with the reflective layer RL2 as an example, the present invention is not limited to this. In another embodiment, the optical identification module 300 may not have the reflective layer RL2.

5 is a schematic cross-sectional view of an optical identification module according to another embodiment of the invention. Please refer to FIG. 5, the optical identification module 400 of this embodiment is similar to the optical identification module 200 in FIG. 3, and the main differences between the two are as follows. In the optical identification module 400, the microlens L3 is mirror-symmetrical (for example, it is bilaterally symmetrical in FIG. 5). By guiding the light through holes TH formed by the openings OP of the shielding layer 120, the light IL condensed by the mirror-symmetric microlens L3 can also be obliquely guided to the sensing region R.

In summary, in the optical identification module of the embodiment of the present invention, a plurality of shielding layers and microlenses are used to obliquely guide external light to the sensing area, so as to effectively improve optical interference (crosstalk) and achieve optical degradation. Noise can improve the image resolution, and it can also avoid the strong light emitted by the detection light source from affecting the recognition result. Therefore, the optical identification module of the embodiment of the present invention can have good identification capabilities.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention. Anyone with ordinary knowledge in the relevant technical field can make some changes and modifications without departing from the spirit and scope of the present invention. The scope of protection of the present invention shall be determined by the scope of the attached patent application.

100, 200, 300, 400: optical recognition module

110: Semiconductor substrate

120, 120A: shielding layer

50: organic light-emitting diode

CG: protective glass

DL: Dielectric

DP: display panel

D1: Arrangement direction

ED: Electronic device

FP: Fingerprint Ridge

IL: light

NIL: light reflected by non-fingerprint ridges

L1, L2, L3: micro lens

OP: opening

PH: pinhole

R: Sensing area

RL1, RL2: reflective layer

TH: Light through hole

FIG. 1 is a schematic cross-sectional view of an optical identification module according to an embodiment of the present invention. 2 is a schematic cross-sectional view of an electronic device according to an embodiment of the invention. 3 is a schematic cross-sectional view of an optical identification module according to another embodiment of the invention. 4A is a schematic cross-sectional view of an optical identification module according to another embodiment of the present invention. 4B is a schematic top view of an optical identification module according to still another embodiment of the present invention. 5 is a schematic cross-sectional view of an optical identification module according to another embodiment of the invention.

100: Optical recognition module

110: Semiconductor substrate

120: shielding layer

DL: Dielectric

D1: Arrangement direction

IL: light

L1: Micro lens

OP: opening

R: Sensing area

TH: Light through hole

Claims (8)

An optical identification module includes: a semiconductor substrate with at least one sensing area; a plurality of shielding layers arranged above the semiconductor substrate, wherein each shielding layer has at least one opening, and the plurality of openings of the shielding layers are formed At least one light through hole, so that external light is obliquely transmitted to the at least one sensing area through the at least one light through hole, wherein the orthographic projection position of each opening on the semiconductor substrate and the at least one sensing area have a Parallel to the displacement of the semiconductor substrate; and a microlens disposed on the opening of the shielding layer farthest from the semiconductor substrate among the shielding layers, so as to obliquely guide external light to the shielding layer through the at least one light through hole In the at least one sensing area, the average tangent slope of one side of the microlens is greater than the average tangent slope of the other side, so as to obliquely guide the oblique light reflected from the fingerprint ridge line of the finger to the at least one sensor. The detection area guides the light not reflected by the fingerprint ridge line to the outside of the at least one sensing area. As described in the first item of the scope of patent application, the orthographic projections of the openings of the shielding layers on the semiconductor substrate are sequentially arranged along an arrangement direction, and the arrangement direction is the same as that of the semiconductor substrate. The surfaces are parallel. For the optical identification module described in item 2 of the scope of patent application, there is an included angle between the extending direction of the at least one light through hole and the semiconductor substrate, and the included angle is not equal to 90 degrees. For the optical identification module described in item 1 of the scope of patent application, the material of the shielding layers is metal. In the optical identification module described in the first item of the scope of patent application, the shielding layers are formed by a metal interconnection of the integrated circuit. As described in the first item of the scope of patent application, the optical identification module further includes: a reflective layer disposed on the top surface of the semiconductor substrate, the reflective layer has at least one pinhole, and the pinhole is formed on the semiconductor substrate. The orthographic projection overlaps the at least one sensing area. The optical identification module according to item 6 of the scope of patent application, wherein the pinhole of the reflective layer and the orthographic projection of the opening on the semiconductor substrate of the shielding layer closest to the semiconductor substrate in the shielding layers overlap with each other . According to the optical identification module described in item 6 of the scope of patent application, the size of the pinhole of the reflective layer is smaller than the size of the sensing area.

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