TWI873610B - Imaging device and fingerprint recognition device - Google Patents

Abstract

An imaging device and fingerprint recognition device. The imaging device includes a shell, a sensor, a filter, and a metalenses. The shell is equipped with a accommodating cavity and a light through hole connected to the accommodating cavity in the first direction. The sensor is assembled in the accommodating cavity, and the sensor and the light through hole are arranged relative in the first direction to receive far-infrared light and achieve imaging. The filter is assembled in the accommodating cavity, and is positioned between the light through hole and the sensor in the first direction. A metalenses is assembled in the accommodating cavity, which includes a substrate and a metasurface structure. The substrate is located between the the light through hole and the filter in the first direction, and the metasurface structure is connected to the side of the substrate facing the light through hole or the side of the substrate away from the light through hole. The above imaging device is advantageous for simplifying the structure.

Description

Imaging device and fingerprint recognition device

This application relates to the field of optical technology, and in particular to an imaging device and a fingerprint recognition device.

Infrared imaging technology is a technology that obtains the thermal radiation information of the target object and converts it into an image visible to the human eye. Compared with visible light imaging technology, this imaging technology has the advantages of concealment, strong anti-interference ability, and good environmental adaptability. Infrared imaging devices usually use optical lenses to focus the infrared light emitted by the target object onto the sensor. The conventional optical lens needs to use a lens group composed of multiple optical lenses to focus or diverge the light, resulting in a complex structure of the infrared imaging device.

In view of this, it is necessary to provide an imaging device that is conducive to simplifying the structure.

The embodiment of the present application provides an imaging device, including a housing, a sensor, a filter and a super lens. The housing is provided with a receiving cavity and a light through hole connected to the receiving cavity along a first direction, and the light through hole facilitates the passage of far infrared light emitted by a target object. The sensor is mounted in the receiving cavity, and the sensor and the light through hole are arranged opposite to each other in the first direction, and are used to receive the far infrared light and realize imaging. The filter is mounted in the receiving cavity, and the filter is located between the light through hole and the sensor in the first direction, and is used to filter and eliminate light other than the far infrared light wavelength. The superlens is assembled in the accommodating cavity. The superlens includes a substrate and a supersurface structure. The substrate is located between the optical through hole and the filter plate in the first direction. The supersurface structure is connected to one side of the substrate facing the optical through hole or one side of the substrate away from the optical through hole. The supersurface structure includes a plurality of columnar structural units arranged in an array and extending along the first direction. The substrate is used to facilitate the far infrared light to pass through. The supersurface structure is used to bend the far infrared light and make the bent far infrared light pass through the filter plate and focus on the sensor.

The technical effects of the embodiments of this application include: In the above-mentioned imaging device, a single super lens can realize the functions of refracting light and focusing. Compared with the traditional lens set, it has the advantages of simple structure, small size and thinness, which is conducive to simplifying the structure of the imaging device. In addition, in the preparation process of the imaging device, it can reduce the tolerance problem caused by the assembly of multiple lenses of the traditional lens set, which is conducive to improving production efficiency and reducing production costs.

，其中，φ為相位；M為衍射階數；N為多項式係數之級數；A_i為正規化徑向孔徑座標中ρ²ⁱ之多項式係數；ρ為元件半徑，A_i之範圍滿足5至30。 Optionally, in some embodiments of the present application, the superlens satisfies the Binary2 surface phase formula

, where φ is the phase; M is the diffraction order; N is the degree of the polynomial coefficient; _Ai is the polynomial coefficient of ρ ²ⁱ in the normalized radial aperture coordinate; ρ is the element radius, and the range of _Ai is 5 to 30.

Optionally, in some embodiments of the present application, along the first direction, the height of the columnar structure unit satisfies 3μm to 15μm.

Optionally, in some embodiments of the present application, the cross section of the columnar structural unit perpendicular to the first direction is circular, and the diameter of the circle ranges from 0.5μm to 5μm.

Optionally, in some embodiments of the present application, the cross-section of the columnar structural unit perpendicular to the first direction is rectangular, and the length range of two adjacent sides of the rectangle satisfies 0.5μm to 5μm respectively.

Optionally, in some embodiments of the present application, the super lens is movably disposed between the light through hole and the filter plate along the first direction.

Optionally, in some embodiments of the present application, the wavelength of the far infrared light satisfies 8μm to 12μm.

Optionally, in some embodiments of the present application, the substrate is made of one of chalcogenide glass, zinc sulfide, zinc selenide, crystalline germanium, and crystalline silicon.

Optionally, in some embodiments of the present application, the metasurface structure is made of crystalline silicon or crystalline germanium.

The embodiments of this application also provide a fingerprint recognition device, including any imaging device described in the above embodiments.

100: Imaging device

200: Fingerprint recognition device

10: Shell

11: Accommodation chamber

12: Light through hole

20: Sensor

30: Filter

40:Super lens

41: Substrate

42:Supersurface structure

421: Columnar structure unit

43: Anti-reflection film layer

X: First direction

Figure 1 shows a schematic diagram of the structure of an imaging device of an embodiment.

Figure 2 shows a schematic diagram of the structure of a super lens in an imaging device of an embodiment.

Figure 3 shows a first structural schematic diagram of a columnar structure unit in an imaging device of an embodiment.

Figure 4 shows a second structural schematic diagram of a columnar structure unit in an imaging device of an embodiment.

FIG5 shows a schematic diagram of the structure of a fingerprint recognition device of a heat dissipation device according to an embodiment.

The following will describe the technical solutions in the embodiments of this application in conjunction with the attached figures in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of them.

It should be noted that when a component is said to be "mounted on" another component, it can be directly on the other component or it can also be located in a central component. When a component is considered to be "set on" another component, it can be directly set on the other component or it can also be located in a central component at the same time.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by technicians in the technical field of this application. The terms used in this specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "or/and" used in this article includes any and all combinations of one or more related listed items.

An imaging device provided in an embodiment of the present application includes a housing, a sensor, a filter and a super lens. The housing is provided with a receiving cavity and a light through hole connected to the receiving cavity along a first direction, and the light through hole facilitates the passage of far-infrared light emitted by a target object. The sensor is mounted in the receiving cavity, and the sensor and the light through hole are arranged opposite to each other in the first direction, and are used to receive far-infrared light and realize imaging. The filter is mounted in the receiving cavity, and the filter is located between the light through hole and the sensor in the first direction, and is used to filter and eliminate light other than the far-infrared light wavelength. The superlens is assembled in the receiving cavity. The superlens includes a substrate and a supersurface structure. The substrate is located between the optical through hole and the filter plate in the first direction. The supersurface structure is connected to one side of the substrate facing the optical through hole or one side of the substrate away from the optical through hole. The supersurface structure includes a plurality of columnar structural units arranged in an array and extending along the first direction. The substrate is used to facilitate the passage of far-infrared light. The supersurface structure is used to bend the far-infrared light and make the bent far-infrared light pass through the filter plate and focus on the sensor.

In the above imaging device, a single super lens can realize the functions of refracting light and focusing. Compared with the traditional lens set, it has the advantages of simple structure, small size and thinness, which is conducive to simplifying the structure of the imaging device. In addition, in the preparation process of the imaging device, it can reduce the tolerance problem caused by the assembly of multiple lenses of the traditional lens set, which is conducive to improving production efficiency and reducing production costs.

The following is a detailed description of some embodiments of this application in conjunction with the attached figures.

Referring to FIG. 1 , an embodiment of the present application provides an imaging device 100, including a housing 10, a sensor 20, a filter 30 and a super lens 40. The housing 10 is provided with a receiving cavity 11 and a light through hole 12 connected to the receiving cavity 11 along a first direction X. The light through hole 12 is used to face the target object so that the far infrared light emitted by the target object can pass through. Optionally, the far infrared light is generated by the radiation of the target object itself.

The sensor 20 is installed in the accommodating cavity 11 and is arranged opposite to the light through hole 12 in the first direction X. The sensor 20 is used to receive far infrared light and realize imaging.

The filter plate 30 is installed in the accommodating cavity 11. The filter plate 30 is located between the light through hole 12 and the sensor 20 in the first direction X. It is used to filter and eliminate light other than the far infrared wavelength, so that the far infrared light can be irradiated to the sensor 20, thereby facilitating clear imaging of the sensor 20.

Please refer to FIG. 2 , the superlens 40 is assembled in the accommodating cavity 11. The superlens 40 includes a substrate 41 and a supersurface structure 42, and the substrate 41 is located between the optical through hole 12 and the filter 30 in the first direction X. The supersurface structure 42 is connected to a side of the substrate 41 facing the optical through hole 12 or a side of the substrate 41 away from the optical through hole 12. Specifically, when the supersurface structure 42 is connected to a side of the substrate 41 facing the optical through hole 12, the far-infrared light passes through the supersurface structure 42 and the substrate 41 in sequence. When the supersurface structure 42 is connected to a side of the substrate 41 away from the optical through hole 12, the far-infrared light passes through the substrate 41 and the supersurface structure 42 in sequence. The super surface structure 42 includes a plurality of columnar structural units 421 arranged in an array and extending along the first direction X.

The substrate 41 is made of a material that is highly transparent to infrared light, and the substrate 41 is used to facilitate the passage of far-infrared light. Optionally, the substrate 41 is made of one of chalcogenide glass, zinc sulfide, zinc selenide, crystalline germanium, and crystalline silicon.

The columnar structure unit 421 is made of infrared high refractive index material, and the metasurface structure 42 is used to bend the far infrared light and make the bent far infrared light pass through the filter plate 30 and focus to the sensor 20, so that the sensor 20 can form a clear image. Optionally, the metasurface structure 42 is made of crystalline silicon or crystalline germanium.

It can be understood that the space between each columnar structure unit 421 can be filled with air or a material that is highly transparent to infrared light.

It should be noted that the metasurface structure 42 is prepared using semiconductor processes, including step-by-step lithography, step-by-step scanning lithography, nanoimprinting, laser direct writing, metal lift-off or ICP etching, etc.

In the imaging device 100, the single super lens 40 can realize the functions of refracting light and focusing. Compared with the traditional lens set, it has the advantages of simple structure, small size and thinness, which is conducive to simplifying the structure of the imaging device 100. In addition, during the preparation process of the imaging device 100, the tolerance problem generated when assembling multiple lenses of the traditional lens set can be reduced, which is conducive to improving production efficiency and reducing production costs.

，其中，φ為相位；M為衍射階數；N為多項式係數之級數；A_i為正規化徑向孔徑座標中ρ²ⁱ之多項式係數，ρ為元件半徑。藉由超透鏡40滿足Binary2面型相位公式，以於超透鏡整個表面上引入連續相變，能夠便於提升超透鏡40之折射與聚焦效果。 In some embodiments, the superlens 40 satisfies the Binary2 surface phase formula

, where φ is the phase; M is the diffraction order; N is the order of the polynomial coefficient; _Ai is the polynomial coefficient of ρ ²ⁱ in the normalized radial aperture coordinate, and ρ is the element radius. By having the superlens 40 satisfy the Binary2 surface phase formula, a continuous phase change is introduced on the entire surface of the superlens, which can facilitate the improvement of the refraction and focusing effects of the superlens 40.

In some embodiments, the range of A _i satisfies 5 to 30 to further enhance the refraction and focusing effects of the super lens 40. Optionally, A _i is 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 and any other value within the range of 5 to 30.

Please continue to refer to FIG. 2. In some embodiments, the height of the columnar structure unit 421 satisfies 3μm to 15μm, so that the height of the columnar structure unit 421 is between the wavelength of far infrared light, thereby improving the refraction and focusing effect of the super lens 40. Optionally, the height of the columnar structure unit 421 is 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, and any other value within the range of 3μm to 15μm.

In some embodiments, the super lens 40 further includes an anti-reflection film layer 43, which is connected to a side of the substrate 41 facing the light through hole 12 and/or a side of the substrate 41 away from the light through hole 12, for increasing the transmittance of far infrared light.

Please refer to FIG. 3. In some embodiments, the cross section of the columnar structure unit 421 perpendicular to the first direction X is circular, and the diameter of the circle satisfies the range of 0.5μm to 5μm, so that the diameter of the columnar structure unit 421 is in the sub-wavelength order, thereby improving the refraction and focusing effect of the super lens 40. Optionally, the diameter of the circle is 0.5μm, 1μm, 1.5μm, 2μm, 2.5μm, 3μm, 3.5μm, 4μm, 4.5μm, 5μm, and any other value within the range of 0.5μm to 5μm.

In some embodiments, all columnar structural units 421 in the metasurface structure 42 have the same height to further enhance the refraction and focusing effects of the superlens 40.

Please refer to FIG. 4 . In some embodiments, the cross section of the columnar structure unit 421 perpendicular to the first direction X is rectangular, and the length range of the two adjacent sides of the rectangle satisfies 0.5μm to 5μm, so that the length and width of the columnar structure unit 421 are between the sub-wavelength level, thereby improving the refraction and focusing effect of the super lens 40. Optionally, the lengths of the two adjacent sides are 0.5μm, 1μm, 1.5μm, 2μm, 2.5μm, 3μm, 3.5μm, 4μm, 4.5μm, 5μm, and any other value within the range of 0.5μm to 5μm.

It is understandable that the columnar structure unit 421 can also be an elliptical cylinder, a hollow elliptical cylinder, a hollow rectangular cylinder, a hollow square cylinder, etc.

In some embodiments, the super lens 40 is movably disposed between the light through hole 12 and the filter 30 along the first direction X, so as to adjust the distance between the super lens 40 and the sensor 20, so as to facilitate clear imaging of the sensor 20.

In some embodiments, the columnar structural units 421 in the metasurface structure 42 can be arranged in a circular, fan-shaped, regular hexagonal, or square array. Those skilled in the art should recognize that the columnar structural units 421 in the metasurface structure 42 can also include other forms of array arrangements, and all of these variations are within the scope of this application.

In some embodiments, the periphery of the superlens 40 is fixed in a support seat, and the support seat is slidably connected to the housing 10 along the first direction X, and the support seat is used to drive the superlens 40 to move along the first direction X. Optionally, the support seat is connected to a drive member such as a motor or a cylinder, or the support seat is connected to an electrostrictive element made of a memory alloy, and the electrostrictive element is extended to different degrees by inputting currents of different magnitudes into the electrostrictive element to drive the support seat to move.

In some embodiments, the wavelength range of far infrared light is 8μm to 12μm, so that the imaging device 100 can image the far infrared light emitted by the human body, which is convenient for application in human body sensing fields such as fingerprint recognition, driverless driving, and body temperature detection.

Furthermore, the wavelength range of the far infrared light is 10μm, so as to further facilitate the imaging device 100 to image the far infrared light emitted by the human body.

Please refer to Figure 5. The embodiment of the present application also provides a fingerprint recognition device 200, including any one of the imaging devices 100 in the above embodiments. The fingerprint recognition device 200 also includes a recognition structure, which is used to receive the infrared fingerprint image generated by the imaging device 100 and perform fingerprint recognition.

In summary, the imaging device 100 and fingerprint recognition device 200 described above can realize the functions of refracting light and focusing through a single super lens 40. Compared with the traditional lens set, it has the advantages of simple structure, small size and thinness, which is conducive to simplifying the structure of the imaging device 100. In addition, during the preparation process of the imaging device 100, it can reduce the tolerance problem caused by the assembly of multiple lenses of the traditional lens set, which is conducive to improving production efficiency and reducing production costs.

Ordinary technical personnel in this technical field should recognize that the above embodiments are only used to illustrate this application, and are not used to limit this application. As long as they are within the scope of the essence of this application, appropriate changes and modifications to the above embodiments are within the scope of disclosure of this application.

100: Imaging device

10: Shell

11: Accommodation chamber

12: Light through hole

20: Sensor

30: Filter

40:Super lens

X: First direction

Claims (10)

An imaging device, the improvement of which is that it comprises: a housing, provided with a receiving cavity and a light through hole connected to the receiving cavity along a first direction, the light through hole facilitating the passage of far-infrared light emitted by a target object; a sensor, mounted in the receiving cavity, the sensor and the light through hole being arranged opposite to each other in the first direction, for receiving the far-infrared light and realizing imaging; a filter, mounted in the receiving cavity, the filter being located between the light through hole and the sensor in the first direction, for filtering and eliminating light other than the far-infrared light wavelength; a super lens, mounted in the receiving cavity, the super lens The invention comprises a substrate and a metasurface structure. The substrate is located between the optical through hole and the filter plate in the first direction. The metasurface structure is connected to one side of the substrate facing the optical through hole or one side of the substrate away from the optical through hole. The metasurface structure comprises a plurality of columnar structural units arranged in an array and extending along the first direction. The substrate is used to facilitate the far infrared light to pass through. The metasurface structure is used to bend the far infrared light and make the bent far infrared light pass through the filter plate and focus to the sensor. The space between each of the columnar structural units is filled with a material with high transmittance to infrared light. The imaging device as claimed in claim 1, wherein the superlens satisfies the Binary2 surface phase formula

, where φ is the phase; M is the diffraction order; N is the degree of the polynomial coefficient; _Ai is the polynomial coefficient of ρ ²ⁱ in the normalized radial aperture coordinate; ρ is the element radius, and the range of Ai is 5 to 30. An imaging device as described in claim 1, wherein the height of the columnar structure unit along the first direction satisfies 3μm to 15μm. An imaging device as described in claim 3, wherein the cross section of the columnar structure unit perpendicular to the first direction is circular, and the diameter range of the circle satisfies 0.5μm to 5μm. An imaging device as described in claim 3, wherein the cross section of the columnar structure unit perpendicular to the first direction is rectangular, and the length range of two adjacent sides of the rectangle satisfies 0.5μm to 5μm respectively. An imaging device as described in claim 1, wherein the super lens is movably disposed between the light passage hole and the filter plate along the first direction. An imaging device as described in claim 1, wherein the wavelength of the far infrared light satisfies 8μm to 12μm. An imaging device as described in claim 1, wherein the substrate is made of one of chalcogenide glass, zinc sulfide, zinc selenide, crystalline germanium, and crystalline silicon. An imaging device as described in claim 1, wherein the metasurface structure is made of crystalline silicon or crystalline germanium. A fingerprint recognition device, the improvement of which comprises an imaging device as described in any one of claims 1 to 9.

Images