CN114114495B - Tee bend light filter and biological identification system thereof - Google Patents
Tee bend light filter and biological identification system thereof Download PDFInfo
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- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 112
- 239000000377 silicon dioxide Substances 0.000 claims abstract description 56
- 235000012239 silicon dioxide Nutrition 0.000 claims abstract description 53
- 230000003287 optical effect Effects 0.000 claims abstract description 50
- AZCUJQOIQYJWQJ-UHFFFAOYSA-N oxygen(2-) titanium(4+) trihydrate Chemical compound [O-2].[O-2].[Ti+4].O.O.O AZCUJQOIQYJWQJ-UHFFFAOYSA-N 0.000 claims abstract description 50
- 239000000463 material Substances 0.000 claims abstract description 19
- 238000000034 method Methods 0.000 claims abstract description 13
- 238000000151 deposition Methods 0.000 claims abstract description 10
- 238000007747 plating Methods 0.000 claims abstract description 6
- 239000010410 layer Substances 0.000 claims description 211
- 238000001914 filtration Methods 0.000 claims description 20
- 238000003384 imaging method Methods 0.000 claims description 12
- 239000002356 single layer Substances 0.000 claims description 12
- 239000011521 glass Substances 0.000 claims description 4
- 238000000926 separation method Methods 0.000 claims description 4
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 claims description 3
- 239000000758 substrate Substances 0.000 claims 1
- 238000005516 engineering process Methods 0.000 abstract description 5
- 238000004519 manufacturing process Methods 0.000 abstract description 4
- 230000000903 blocking effect Effects 0.000 abstract 2
- 238000002834 transmittance Methods 0.000 description 16
- 238000010586 diagram Methods 0.000 description 7
- 238000000411 transmission spectrum Methods 0.000 description 7
- 230000008021 deposition Effects 0.000 description 5
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 4
- 230000001815 facial effect Effects 0.000 description 3
- 150000002500 ions Chemical class 0.000 description 3
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N ZrO2 Inorganic materials O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 229910052746 lanthanum Inorganic materials 0.000 description 2
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 description 2
- ORUIBWPALBXDOA-UHFFFAOYSA-L magnesium fluoride Chemical compound [F-].[F-].[Mg+2] ORUIBWPALBXDOA-UHFFFAOYSA-L 0.000 description 2
- 229910001635 magnesium fluoride Inorganic materials 0.000 description 2
- ZKATWMILCYLAPD-UHFFFAOYSA-N niobium pentoxide Inorganic materials O=[Nb](=O)O[Nb](=O)=O ZKATWMILCYLAPD-UHFFFAOYSA-N 0.000 description 2
- URLJKFSTXLNXLG-UHFFFAOYSA-N niobium(5+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Nb+5].[Nb+5] URLJKFSTXLNXLG-UHFFFAOYSA-N 0.000 description 2
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 2
- BPUBBGLMJRNUCC-UHFFFAOYSA-N oxygen(2-);tantalum(5+) Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Ta+5].[Ta+5] BPUBBGLMJRNUCC-UHFFFAOYSA-N 0.000 description 2
- RVTZCBVAJQQJTK-UHFFFAOYSA-N oxygen(2-);zirconium(4+) Chemical compound [O-2].[O-2].[Zr+4] RVTZCBVAJQQJTK-UHFFFAOYSA-N 0.000 description 2
- 238000000985 reflectance spectrum Methods 0.000 description 2
- PBCFLUZVCVVTBY-UHFFFAOYSA-N tantalum pentoxide Inorganic materials O=[Ta](=O)O[Ta](=O)=O PBCFLUZVCVVTBY-UHFFFAOYSA-N 0.000 description 2
- 239000004408 titanium dioxide Substances 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 239000011247 coating layer Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000000295 complement effect Effects 0.000 description 1
- 238000005566 electron beam evaporation Methods 0.000 description 1
- 238000003331 infrared imaging Methods 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 238000003333 near-infrared imaging Methods 0.000 description 1
- 210000000056 organ Anatomy 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/20—Filters
- G02B5/28—Interference filters
- G02B5/285—Interference filters comprising deposited thin solid films
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/20—Filters
- G02B5/28—Interference filters
- G02B5/283—Interference filters designed for the ultraviolet
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Optical Filters (AREA)
Abstract
The invention relates to a three-way optical filter, comprising: the ultraviolet light blocking film comprises a transparent base layer, a tee joint filter film layer and an ultraviolet light blocking film layer; the three-way filter film layer and the ultraviolet light cut-off film layer are formed by alternately stacking, depositing and plating high-refractive-index material layers and low-refractive-index material layers. Through the alternate stacking of the silicon dioxide layer and the titanium pentoxide layer and the alternate stacking of the titanium pentoxide layer and the silicon dioxide layer, the three-pass band is formed, so that the three-pass band infrared recognition method can be simultaneously applied to two infrared wavelengths, the combined use of a human face and iris recognition mode is realized, and the recognition accuracy is greatly improved. In addition, due to the adoption of the RGB+IR sensor technology, the camera component and the infrared sensing component can be integrated together, so that the internal space of the electronic equipment can be effectively saved, and the production cost is greatly reduced.
Description
Technical Field
The invention relates to the field of optical coating filters, in particular to a three-way filter and a biological identification system thereof.
Background
Face recognition and other advanced biometric technologies are becoming more popular in mobile devices and notebook computers, increasingly replacing digital passwords and fingerprint authentication. With the advent of rgb+ir sensors, they can combine support color and infrared imaging applications and can reduce overall system cost, as well as provide IR-based biometric capability for face recognition and gesture interfaces for a range of devices, including smartphones, tablets, notebooks, etc. Meanwhile, the imaging device with integrated design can also reduce the requirement on equipment space and accords with aesthetic industrial design. The dual-pass filter can cut off infrared light, high-transmittance visible light and improved photographing performance of the camera component. But also can penetrate a part of infrared light needed by the infrared sensor, thereby realizing the function of biological recognition.
In order to improve the accuracy of biological identification by adopting an RGB+IR sensor scheme, a plurality of light sources can be adopted to emit light rays with different wave bands, and the characteristics of different organs of the identified object can be respectively extracted. Typical examples are identification using an iris feature recognition method using a 850nm band and facial feature recognition method using a 960nm band, however, there is no filter capable of transmitting light in both infrared bands. Therefore, there is a need in the art for a solution with three pass bands that can transmit light in both infrared bands and visible light at the same time.
Disclosure of Invention
The invention aims to provide a three-way optical filter and a biological recognition system thereof, which solve the defect that no optical filter capable of transmitting light and visible light required by iris feature recognition and facial feature recognition at the same time exists at present.
In order to achieve the above object, the present invention provides the following solutions:
a three-way filter, the filter comprising:
a transparent base layer;
the tee joint filter film layer and the ultraviolet light cut-off film layer are respectively plated on two sides of the transparent base layer;
the tee filter film layer and the ultraviolet light cut-off film layer are formed by alternately stacking, depositing and plating high-refractive-index material layers and low-refractive-index material layers.
A three-way filter, the filter comprising:
a transparent base layer;
an ultraviolet light cut-off tee filter film layer plated on one side of the transparent base layer;
an anti-reflection film layer plated on the other side of the transparent base layer;
the ultraviolet light cut-off tee filtering film layer and the anti-reflection film layer are formed by alternately stacking, depositing and plating high-refractive-index material layers and low-refractive-index material layers.
Optionally, the transparent base layer is made of one of glass, an acrylic plate and a film, and the thickness is 0.2-0.5 mm.
Optionally, the high refractive index material layer is composed of at least one of titanium pentoxide, titanium dioxide, zirconium dioxide, tantalum pentoxide, niobium pentoxide and lanthanum titanate;
the low refractive index material layer is composed of at least one of silicon dioxide, magnesium fluoride and aluminum oxide.
Optionally, the three-way filter film layer is formed by alternately stacking a silicon dioxide layer and a titanium pentoxide layer; the total number of the silicon dioxide layers and the titanium pentoxide layers is 50-200;
in the three-way filter film layer, the single-layer thickness of each titanium pentoxide layer is 1-400 nm, and the single-layer thickness of each silicon dioxide layer is 1-1000 nm.
Optionally, the ultraviolet light cut-off film layer is formed by alternately stacking a titanium pentoxide layer and a silicon dioxide layer; the total number of the titanium pentoxide layers and the silicon dioxide layers is 10-50;
in the ultraviolet light cut-off film layer, the single-layer thickness of each titanium pentoxide layer is 1-200 nm, and the single-layer thickness of each silicon dioxide layer is 1-300 nm.
Optionally, the three-way filter suppresses light between the first wavelength and the second wavelength, light between the third wavelength and the fourth wavelength, light between the fifth wavelength and the sixth wavelength, and light greater than the seventh wavelength in the incident light; the first wavelength is smaller than the second wavelength, the second wavelength is smaller than the third wavelength, the third wavelength is smaller than the fourth wavelength, the fourth wavelength is smaller than the fifth wavelength, the fifth wavelength is smaller than the sixth wavelength, and the sixth wavelength is smaller than the seventh wavelength;
the first wavelength belongs to an ultraviolet light wave band, the second wavelength belongs to an ultraviolet light or visible light wave band, the third wavelength belongs to a visible light wave band, and the fourth wavelength, the fifth wavelength, the sixth wavelength and the seventh wavelength belong to a near infrared light wave band;
the first passband of the three-way filter is between the second wavelength and the third wavelength, the second passband is between the fourth wavelength and the fifth wavelength, and the third passband is between the sixth wavelength and the seventh wavelength.
A biometric imaging device, the device comprising: the device comprises an optical lens, a tee joint optical filter, an image sensor and an image signal processor;
the optical signals sequentially pass through the optical lens and the three-way optical filter, are read by the image sensor, and are then transmitted to the image signal processor for processing;
the three-way filter is used for filtering, and only allows light in a visible light long section and a set infrared wavelength section to pass through;
the image sensor is an RGB+IR image sensor and is used for acquiring light transmitted by the three-way optical filter to obtain a light image array;
the image signal processor is used for filtering infrared signals in the light image array when the infrared signals are not needed; when the specific infrared signal is needed, the specific infrared signal in the optical image array is reserved.
A biometric identification system, the system comprising:
a three-way filter for filtering, which allows only light of a visible light wavelength band and a set infrared wavelength band to pass through;
the RGB+IR image sensor is used for acquiring the light transmitted by the three-way optical filter to obtain a light image array;
a data separation unit for separating the black-and-white image data stream and the RGB image data stream in the optical image array;
an identification unit for performing biometric identification using the black-and-white image data stream;
and the display unit is used for processing the RGB image data stream for display by a display.
A method of biometric identification, the method comprising:
filtering by using a three-way filter, only allowing light in a visible light wavelength band and a set infrared wavelength band to pass through;
the RGB+IR image sensor is utilized to obtain the light transmitted by the three-way filter, and a light image array is obtained;
separating a black and white image data stream and an RGB image data stream in the optical image array;
performing biological recognition by using the black-and-white image data stream;
processing the RGB image data stream for display by a display.
According to the specific embodiment provided by the invention, the invention discloses the following technical effects:
the three-way filter is formed by alternately stacking a silicon dioxide layer and a titanium pentoxide layer, and after the ultraviolet light cut-off film is formed by alternately stacking a titanium pentoxide layer and a silicon dioxide layer, the three-way filter is sequentially formed by the three-way filter film, a transparent base layer and the ultraviolet light cut-off film from bottom to top, so that visible light with the wavelength of 440-630nm and infrared light with the specified wavelength range around 850nm and 960nm can pass through, and the average transmittance is more than 95%; cut off ultraviolet light with wavelength of 350-410nm and infrared light with wavelength of 670-810nm, 890-920nm and 1000-1100nm, and average transmittance is less than 3%.
The biological recognition system adopting the three-way filter design can be simultaneously applied to two infrared wavelengths, so that the combination of a face recognition mode and an iris recognition mode is realized, and the recognition accuracy is greatly improved. In addition, due to the adoption of the RGB+IR sensor technology, the camera component and the infrared sensing component can be integrated together, so that the internal space of the electronic equipment can be effectively saved, and the production cost is greatly reduced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic structural diagram of a three-way filter according to an embodiment of the present invention.
FIG. 2 is a graph showing transmittance spectra of an ultraviolet light cut-off film layer of a three-way filter according to an embodiment of the present invention.
FIG. 3 is a transmittance spectrum of a three-way filter layer of a three-way filter according to an embodiment of the present invention.
FIG. 4 is a transmittance spectrum of a three-way filter according to an embodiment of the present invention.
Fig. 5 is a schematic structural diagram of a three-way filter according to a second embodiment of the present invention.
FIG. 6 is a reflectance spectrum of an anti-reflection film layer of a three-way filter according to a second embodiment of the present invention.
FIG. 7 is a transmittance spectrum of a three-way filter according to a second embodiment of the present invention.
Fig. 8 is a schematic structural diagram of a biometric imaging device according to a third embodiment of the present invention.
Fig. 9 is a schematic diagram of a three-way filter for suppressing incident light bands of a biometric imaging device according to a third embodiment of the present invention.
Fig. 10 is a schematic structural diagram of a biometric identification system according to a fourth embodiment of the present invention.
Fig. 11 is a diagram illustrating a basic operation mode of a biometric identification system according to a fourth embodiment of the present invention.
Fig. 12 is a schematic diagram of a control method of a biometric identification system according to a fourth embodiment of the present invention.
Symbol description:
10. 11-a transparent base layer; 20-a tee filter film layer; 30-ultraviolet light cut-off film layer; 21-ultraviolet light cut-off tee filter film layer; 31-an anti-reflection film layer; 301-an optical lens; 302-a three-way filter; 303-an image sensor; 304-an image signal processor; m1-a three-way filter; an M2-RGB+IR image sensor; m3-a data separation unit; m4-recognition unit; m5-display element.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The invention aims to provide a three-way optical filter and a biological recognition system thereof, which solve the defect that no optical filter capable of transmitting light and visible light required by iris feature recognition and facial feature recognition at the same time exists at present.
In order that the above-recited objects, features and advantages of the present invention will become more readily apparent, a more particular description of the invention will be rendered by reference to the appended drawings and appended detailed description.
Embodiment one:
as shown in fig. 1, an embodiment of the present invention provides a three-way filter, which includes:
a transparent base layer 10;
the three-way filter film layer 20 and the ultraviolet light cut-off film layer 30 are respectively plated on two sides of the transparent base layer 10; the transmittance spectrum of the uv cut-off film layer 30 is shown in fig. 2, and the transmittance spectrum of the three-way filter film layer 20 is shown in fig. 3.
The transparent base layer 10 is made of one of glass, an acrylic plate and a film, and has a thickness of 0.2-0.5 mm; the preferred material type is Schottky white glass (type: D263T eco), and the thickness includes, but is not limited to, 0.03-2 mm, preferably 0.2-0.5 mm.
The three-way filter film layer 20 and the ultraviolet light cut-off film layer 30 are formed by alternately stacking, depositing and plating high-refractive-index material layers and low-refractive-index material layers.
Wherein the high refractive index material layer is composed of at least one of titanium pentoxide, titanium dioxide, zirconium dioxide, tantalum pentoxide, niobium pentoxide and H4 (lanthanum titanate); the low refractive index material layer is composed of at least one of silicon dioxide, magnesium fluoride and aluminum oxide.
As an alternative implementation manner, the three-way filter film layer 20 in the embodiment of the present invention is formed by alternately stacking a silicon dioxide layer and a titanium pentoxide layer; the total number of the silicon dioxide layers and the titanium pentoxide layers is 50-200; in the three-way filter film layer, the single-layer thickness of each titanium pentoxide layer is 1-400 nm, and the single-layer thickness of each silicon dioxide layer is 1-1000 nm.
The ultraviolet light cut-off film layer 30 is formed by alternately stacking a titanium pentoxide layer and a silicon dioxide layer; the total number of the titanium pentoxide layers and the silicon dioxide layers is 10-50; in the ultraviolet light cut-off film layer, the single-layer thickness of each titanium pentoxide layer is 1-200 nm, and the single-layer thickness of each silicon dioxide layer is 1-300 nm.
The three-way filter provided by the embodiment of the invention suppresses light between the first wavelength and the second wavelength, light between the third wavelength and the fourth wavelength, light between the fifth wavelength and the sixth wavelength, and light greater than the seventh wavelength in incident light; the first wavelength is smaller than the second wavelength, the second wavelength is smaller than the third wavelength, the third wavelength is smaller than the fourth wavelength, the fourth wavelength is smaller than the fifth wavelength, the fifth wavelength is smaller than the sixth wavelength, and the sixth wavelength is smaller than the seventh wavelength;
the first wavelength belongs to an ultraviolet light wave band, the second wavelength belongs to an ultraviolet light or visible light wave band, the third wavelength belongs to a visible light wave band, and the fourth wavelength, the fifth wavelength, the sixth wavelength and the seventh wavelength belong to a near infrared light wave band;
the first passband of the three-way filter is between the second wavelength and the third wavelength, the second passband is between the fourth wavelength and the fifth wavelength, and the third passband is between the sixth wavelength and the seventh wavelength.
The average transmissivity of the passband of the three-way optical filter is more than 95 percent, and the average transmissivity of the cutoff band is less than 3 percent; the three-way optical filter is applied to an imaging device and a biological recognition system.
As a specific implementation manner, the three-way filter film layer 20 in the embodiment of the present invention is formed by alternately stacking a silicon dioxide layer and a titanium pentoxide layer; the first layer is a silicon dioxide layer, the second layer is a titanium pentoxide layer, the third layer is a silicon dioxide layer, the fourth layer is a titanium pentoxide layer … …, the layers are alternately stacked in sequence, and the last layer is a silicon dioxide layer. Wherein the total number of the silicon dioxide layer and the titanium pentoxide layer is 129. The total number of silica layers was 65 and the total number of titanium pentoxide layers was 64, see table 1.
Table 1: material and film thickness meter of each layer of three-way filter film layer 20
The ultraviolet light cut-off film layer 30 is formed by alternately stacking a titanium pentoxide layer and a silicon dioxide layer; the first layer is a titanium pentoxide layer, the second layer is a silicon dioxide layer, the third layer is a titanium pentoxide layer, the fourth layer is a silicon dioxide layer … …, the silicon dioxide layers are alternately stacked in sequence, and the last layer is a silicon dioxide layer. Wherein the total number of layers of the titanium pentoxide layer and the silicon dioxide layer is 20, and the total number of layers of the titanium pentoxide layer and the silicon dioxide layer is 10 respectively, see table 2.
Table 2: each layer material and film thickness meter of ultraviolet light cut-off film layer 30
Wherein, the deposition of the titanium pentoxide layer and the silicon dioxide adopts electron beam evaporation for ion auxiliary deposition, the thickness control method adopts extremum method control, and plating parameters are optimized. Wherein the deposition rate of the titanium pentoxide layer is less than 4A/S, and the ion source current is 900-1500 mA; the deposition rate of silicon dioxide is less than 12A/S, and the ion source current is 600-1500 mA; vacuum degree during deposition is 1.0x10 -2 ～1.6x10 -2 pa。
In addition, the three-way filter provided by the embodiment of the invention can further comprise an absorption coating layer between the transparent base layer 10 and the ultraviolet light cut-off film 30.
The three-way filter provided by the embodiment of the invention comprises a three-way filter film layer 20 formed by alternately stacking a silicon dioxide layer and a titanium pentoxide layer, and an ultraviolet light cut-off film layer 30 formed by alternately stacking a titanium pentoxide layer and a silicon dioxide layer, wherein the three-way filter film layer 20, the transparent base layer 10 and the ultraviolet light cut-off film layer 30 sequentially form the three-way filter from top to bottom, so that visible light with the wavelength of 440-630nm and infrared light with the specified wavelength range around 850nm and 960nm can pass through, and the average transmittance is more than 95%; the ultraviolet light with the wavelength of 350-410nm and the infrared light with the wavelength of 670-810nm, 890-920nm and 1000-1100nm are cut off, the average transmittance is less than 3%, the transmittance spectrum chart (incidence angle is 0 DEG) is shown in figure 4, and the filtering characteristic data are shown in the following table 3 and table 4.
Table 3: the three-way optical filter passband filtering characteristic data provided by the embodiment of the invention
Table 4: the three-way filter cut-off band filter characteristic data provided by the embodiment of the invention
Wherein the first passband is a visible light passband having a wavelength of 430nm to 640nm and a fwhm (FullWidth At Half Maximum) of 210nm; the second passband is near infrared passband, the wavelength is 825nm to 875nm, and the FWHM is 50nm; the third passband is a near infrared passband, the wavelength is 935nm to 985nm, and the FWHM is 50nm; the three do not overlap. The average transmissivity of the optical filter is more than 97% within the passband; outside the pass band (cut-off band), the transmittance of the filter is less than 2% on average. Therefore, the three-way optical filter provided by the embodiment of the invention can be applied to a biological identification system with a plurality of wavelengths applied simultaneously, has high peak transmittance and deeper cut-off, inhibits halation and temperature drift, and further effectively improves the identification accuracy.
Embodiment two:
as shown in fig. 5, an embodiment of the present invention provides a three-way filter, which includes a transparent base layer 11, an ultraviolet light cut-off three-way filter film layer 21 disposed on an upper surface of the transparent base layer 11, and an anti-reflection film layer 31 disposed on a lower surface of the transparent base layer 11, unlike the other embodiments. The reflectance spectrum of the anti-reflection film 31 is shown in FIG. 6.
The ultraviolet light cut-off tee filter film layer 21 is formed by alternately stacking a silicon dioxide layer and a titanium pentoxide layer; the first layer is a silicon dioxide layer, the second layer is a titanium pentoxide layer, the third layer is a silicon dioxide layer, the fourth layer is a titanium pentoxide layer … …, the layers are alternately stacked in sequence, and the last layer is a silicon dioxide layer. Wherein the total number of silica layers and the total number of titanium pentoxide layers is 143, the total number of silica layers is 72, and the total number of titanium pentoxide layers is 71, see table 5.
Table 5: material of each layer and film thickness meter of three-way filter film layer 21
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The antireflection film 31 is a broadband antireflection film, which is formed by alternately stacking a titanium pentoxide layer and a silicon dioxide layer; the first layer is a titanium pentoxide layer, the second layer is a silicon dioxide layer, the third layer is a titanium pentoxide layer, the fourth layer is a silicon dioxide layer … …, the silicon dioxide layers are alternately stacked in sequence, and the last layer is a silicon dioxide layer. Wherein the total number of layers of the titanium pentoxide layer and the silicon dioxide layer was 8, and the total number of layers of the titanium pentoxide layer and the silicon dioxide layer was 4, respectively, see table 6.
Table 6: materials of each layer of the antireflection film 31 and film thickness meter
The three-way filter provided by the embodiment of the invention comprises an ultraviolet light cut-off three-way filter film layer 21 formed by alternately stacking a silicon dioxide layer and a titanium pentoxide layer, and an anti-reflection film layer 31 formed by alternately stacking a titanium pentoxide layer and a silicon dioxide layer, wherein the three-way filter is sequentially formed by the ultraviolet light cut-off three-way filter film layer 21, a transparent base layer 11 and the anti-reflection film layer 31 from top to bottom, so that visible light with the wavelength of 440-630nm and infrared light with the specified wavelength range around 850nm and 960nm can pass through, and the average transmittance is more than 95%; the ultraviolet light with the wavelength of 350-410nm and the infrared light with the wavelength of 670-810nm, 890-920nm and 1000-1100nm are cut off, the average transmittance is less than 3%, the transmittance spectrum chart (incidence angle of 0 DEG) is shown in figure 7, and the filtering characteristic data are shown in the following table 7 and table 8.
Table 7: the three-way filter passband filter characteristic data provided in the second embodiment of the invention
Table 8: the tee filter cut-off band filtering characteristic data provided by the embodiment II of the invention
Wherein the first passband is a visible light passband having a wavelength of 430nm to 640nm and a fwhm (FullWidth At Half Maximum) of 210nm; the second passband is near infrared passband, the wavelength is 825nm to 875nm, and the FWHM is 50nm; the third passband is a near infrared passband, the wavelength is 935nm to 985nm, and the FWHM is 50nm; the three do not overlap. The average transmissivity of the optical filter is greater than 96.4% within the passband; outside the pass band (cut-off band), the transmittance of the filter is less than 2% on average. Therefore, the three-way optical filter can be applied to a biological identification system with multiple wavelengths applied simultaneously, has high peak transmittance and deeper cut-off, inhibits halation and temperature drift, and further effectively improves the identification accuracy.
Embodiment III:
referring to fig. 8, an embodiment of the present invention provides a biometric imaging device, which includes, unlike the other embodiments: an optical lens 301, a three-way filter 302, an image sensor 303, and an image signal processor 304; the three-way filter 302 is provided in the first or second embodiment.
The optical signal sequentially passes through the optical lens 301 and the three-way optical filter 302, is read by the image sensor 303, and is then transmitted to the image signal processor 304 for processing;
the three-way filter 302 is used for filtering, and only allows light of a visible light wavelength band and a set infrared wavelength band to pass through, as shown in fig. 9;
a three-way filter 302 is provided between the optical lens 301 and the image sensor 303, the three-way filter 302 being for suppressing light having a wavelength between the first wavelength and the second wavelength, and light having a wavelength between the third wavelength and the fourth wavelength, and light having a wavelength between the fifth wavelength and the sixth wavelength, and light having a wavelength greater than the seventh wavelength, among the incident light; the first wavelength is smaller than the second wavelength, the second wavelength is smaller than the third wavelength, the third wavelength is smaller than the fourth wavelength, the fourth wavelength is smaller than the fifth wavelength, the fifth wavelength is smaller than the sixth wavelength, and the sixth wavelength is smaller than the seventh wavelength. The first wavelength belongs to the ultraviolet light band, the second wavelength belongs to the ultraviolet light or visible light band, the third wavelength belongs to the visible light band, and the fourth and fifth wavelengths and the sixth and seventh wavelengths belong to the near infrared light band.
It is understood that the wavelength band between the second wavelength and the third wavelength includes a visible light wavelength band, where the visible light wavelength band belongs to a wavelength band that needs to be collected by the imaging device, and for a wavelength band between the first wavelength and the second wavelength, belongs to an ultraviolet wavelength band that needs to be filtered. The wave bands between the third wavelength and the fourth wavelength, the wave bands between the fifth wavelength and the sixth wavelength, and the wave bands larger than the seventh wavelength belong to near infrared wave bands needing filtering, and the wave bands between the fourth wavelength and the seventh wavelength belong to near infrared wave bands needing selective filtering.
As a specific embodiment, the first wavelength is 300 to 350nm, the second wavelength is 390 to 430nm, the third wavelength is 640 to 700nm, the fourth wavelength is 800 to 840nm, the fifth wavelength is 850 to 900nm, the sixth wavelength is 910 to 950nm, and the seventh wavelength is 960 to 1050nm.
The image sensor 303 is an rgb+ir image sensor, which can simultaneously capture white light RGB and specific infrared light in a single CMOS (Complementary Metal Oxide Semiconductor ) image sensor, and is used for acquiring light transmitted by the three-way filter to obtain an optical image array;
the image signal processor 304 is configured to filter out an infrared signal in the optical image array when the infrared signal is not needed; when the specific infrared signal is needed, the specific infrared signal in the optical image array is reserved.
The biological identification imaging device provided by the embodiment of the invention utilizes the three-way optical filter, and can pass light of three pass bands and infrared light of two pass bands, so that the device can be applied to a biological identification system with multiple wavelengths applied simultaneously, has high peak transmittance and deeper cut-off, inhibits halation and temperature drift, and further effectively improves the identification accuracy. In addition, due to the adoption of the RGB+IR sensor technology, the camera component and the infrared sensing component can be integrated together, so that the internal space of the electronic equipment can be effectively saved, and the production cost is greatly reduced.
Embodiment four:
referring to fig. 10, an embodiment of the present invention provides a biometric identification system, whose specific operation mode is shown in fig. 11, unlike the other embodiments, the system includes:
a three-way filter M1 for filtering, which allows only light of a visible light wavelength band and a set infrared wavelength band to pass therethrough; the three-way filter M1 is adopted for filtering, and only light in a color wavelength band and a set infrared wavelength band is allowed to pass through; the light source has high transmittance for RGB light and also has high transmittance for near infrared light with specific wavelength of 730-1100 nm, and other near infrared light cannot pass through. The image sensor commonly used at present generally has better near infrared imaging effect, and near infrared light with the wavelength of 730 to 1100nm is used here, for example, the wavelength of 850nm or 960nm, 1000nm and the like.
The RGB+IR image sensor M2 is used for acquiring the light transmitted by the three-way optical filter to obtain an optical image array; the optical image array is read by the image processor and then stored in the image original data buffer area.
A data separation unit M3, configured to separate a black-and-white image data stream and an RGB image data stream in the optical image array; the black and white image data stream and the RGB image data stream are separated in an image signal processor, and the IR and RGB data are separated by software to obtain an infrared black and white image data stream and an RGB image data stream.
An identification unit M4 for performing biometric identification using the black-and-white image data stream;
and the display unit M5 is used for processing the RGB image data stream for display by a display.
The embodiment of the invention also provides a biological identification method, referring to fig. 12, the method comprises the following steps:
s1, filtering by using a three-way filter M1, and only allowing light in a visible light wavelength band and a set infrared wavelength band to pass through;
s2, acquiring light transmitted by the three-way filter by using an RGB+IR image sensor M2 to obtain a light image array;
s3, separating a black-and-white image data stream and an RGB image data stream in the optical image array;
s4, performing biological recognition by using the black-and-white image data stream;
s5, processing the RGB image data stream for display.
The biological recognition system provided by the embodiment of the invention utilizes the three-way optical filter, and can pass light of three pass bands and infrared light of two pass bands, so that the device can be applied to a biological recognition system with multiple wavelengths applied simultaneously, has high peak transmittance and deeper cut-off, inhibits halation and temperature drift, further effectively improves the recognition accuracy, can be simultaneously applied to two infrared wavelengths, realizes the combined use of a face and iris recognition mode, and greatly improves the recognition accuracy. In addition, due to the adoption of the RGB+IR sensor technology, the camera component and the infrared sensing component can be integrated together, so that the internal space of the electronic equipment can be effectively saved, and the production cost is greatly reduced
In this specification, all embodiments are mainly described and are different from other embodiments, and the same similar parts between the embodiments are mutually referred to.
The principles and embodiments of the present invention have been described herein with reference to specific examples, the description of which is intended only to assist in understanding the methods of the present invention and the core ideas thereof; also, it is within the scope of the present invention to be modified by those of ordinary skill in the art in light of the present teachings. In view of the foregoing, this description should not be construed as limiting the invention.
Claims (4)
1. A biometric imaging device, the device comprising: the device comprises an optical lens, a tee joint optical filter, an image sensor and an image signal processor;
the optical signals sequentially pass through the optical lens and the three-way optical filter, are read by the image sensor, and are then transmitted to the image signal processor for processing;
the three-way filter is used for filtering, and only allows light in a visible light long section and a set infrared wavelength section to pass through;
the image sensor is an RGB+IR image sensor and is used for acquiring light transmitted by the three-way optical filter to obtain a light image array;
the image signal processor is used for filtering infrared signals in the light image array when the infrared signals are not needed; when the specific infrared signal is needed, the specific infrared signal in the optical image array is reserved;
the three-way filter includes:
a transparent base layer;
an ultraviolet light cut-off tee filter film layer plated on one side of the transparent base layer;
an anti-reflection film layer plated on the other side of the transparent base layer;
the ultraviolet light cut-off tee filtering film layer and the anti-reflection film layer are formed by alternately stacking, depositing and plating high-refractive-index material layers and low-refractive-index material layers;
the tee filter film layer is formed by alternately stacking silicon dioxide layers and titanium pentoxide layers; the total number of the silicon dioxide layers and the titanium pentoxide layers is 50-200;
in the three-way filter film layer, the single-layer thickness of each titanium pentoxide layer is 1-400 nm, and the single-layer thickness of each silicon dioxide layer is 1-1000 nm;
the ultraviolet light cut-off film layer is formed by alternately stacking a titanium pentoxide layer and a silicon dioxide layer; the total number of the titanium pentoxide layers and the silicon dioxide layers is 10-50;
in the ultraviolet light cut-off film layer, the single-layer thickness of each titanium pentoxide layer is 1-200 nm, and the single-layer thickness of each silicon dioxide layer is 1-300 nm;
the three-way optical filter is utilized to pass light with three pass bands and infrared light with two pass bands, so that the device is applied to a biological recognition system with multiple wavelengths applied simultaneously;
the three-way filter suppresses light between a first wavelength and a second wavelength, light between a third wavelength and a fourth wavelength, light between a fifth wavelength and a sixth wavelength, and light greater than a seventh wavelength in incident light; the first wavelength is smaller than the second wavelength, the second wavelength is smaller than the third wavelength, the third wavelength is smaller than the fourth wavelength, the fourth wavelength is smaller than the fifth wavelength, the fifth wavelength is smaller than the sixth wavelength, and the sixth wavelength is smaller than the seventh wavelength;
the first wavelength belongs to an ultraviolet light wave band, the second wavelength belongs to an ultraviolet light or visible light wave band, the third wavelength belongs to a visible light wave band, and the fourth wavelength, the fifth wavelength, the sixth wavelength and the seventh wavelength belong to a near infrared light wave band;
the first passband of the three-way filter is between the second wavelength and the third wavelength, the second passband is between the fourth wavelength and the fifth wavelength, and the third passband is between the sixth wavelength and the seventh wavelength.
2. The biometric imaging device of claim 1, wherein the transparent substrate is made of glass or acrylic and has a thickness of 0.2-0.5 mm.
3. A biometric system based on the biometric imaging device of claim 1, the system comprising:
a three-way filter for filtering, which allows only light of a visible light wavelength band and a set infrared wavelength band to pass through;
the RGB+IR image sensor is used for acquiring the light transmitted by the three-way optical filter to obtain a light image array;
a data separation unit for separating the black-and-white image data stream and the RGB image data stream in the optical image array;
an identification unit for performing biometric identification using the black-and-white image data stream;
and the display unit is used for processing the RGB image data stream for display by a display.
4. A biometric method based on the biometric imaging device of claim 1, the method comprising:
filtering by using a three-way filter, only allowing light in a visible light wavelength band and a set infrared wavelength band to pass through;
the RGB+IR image sensor is utilized to obtain the light transmitted by the three-way filter, and a light image array is obtained;
separating a black and white image data stream and an RGB image data stream in the optical image array;
performing biological recognition by using the black-and-white image data stream;
processing the RGB image data stream for display by a display.
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