CN114114495A - Three-way optical filter and biological identification system thereof - Google Patents
Three-way optical filter and biological identification system thereof Download PDFInfo
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- 230000003287 optical effect Effects 0.000 title claims abstract description 54
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 114
- 239000000377 silicon dioxide Substances 0.000 claims abstract description 57
- 235000012239 silicon dioxide Nutrition 0.000 claims abstract description 56
- 238000001914 filtration Methods 0.000 claims abstract description 40
- 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 38
- 239000000463 material Substances 0.000 claims abstract description 23
- 238000000151 deposition Methods 0.000 claims abstract description 10
- 239000010410 layer Substances 0.000 claims description 226
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 14
- 238000000034 method Methods 0.000 claims description 11
- 238000003384 imaging method Methods 0.000 claims description 10
- 239000011521 glass Substances 0.000 claims description 4
- 238000000926 separation method Methods 0.000 claims description 4
- 239000002356 single layer Substances 0.000 claims description 4
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 3
- MCMNRKCIXSYSNV-UHFFFAOYSA-N ZrO2 Inorganic materials O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 claims description 3
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 claims description 3
- 229910052746 lanthanum Inorganic materials 0.000 claims description 3
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 claims description 3
- ORUIBWPALBXDOA-UHFFFAOYSA-L magnesium fluoride Chemical compound [F-].[F-].[Mg+2] ORUIBWPALBXDOA-UHFFFAOYSA-L 0.000 claims description 3
- 229910001635 magnesium fluoride Inorganic materials 0.000 claims description 3
- ZKATWMILCYLAPD-UHFFFAOYSA-N niobium pentoxide Inorganic materials O=[Nb](=O)O[Nb](=O)=O ZKATWMILCYLAPD-UHFFFAOYSA-N 0.000 claims description 3
- 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 claims description 3
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims description 3
- 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 claims description 3
- RVTZCBVAJQQJTK-UHFFFAOYSA-N oxygen(2-);zirconium(4+) Chemical compound [O-2].[O-2].[Zr+4] RVTZCBVAJQQJTK-UHFFFAOYSA-N 0.000 claims description 3
- PBCFLUZVCVVTBY-UHFFFAOYSA-N tantalum pentoxide Inorganic materials O=[Ta](=O)O[Ta](=O)=O PBCFLUZVCVVTBY-UHFFFAOYSA-N 0.000 claims description 3
- 239000004408 titanium dioxide Substances 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
- 239000010408 film Substances 0.000 description 57
- 238000002834 transmittance Methods 0.000 description 17
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 8
- 238000010586 diagram Methods 0.000 description 7
- 238000000411 transmission spectrum Methods 0.000 description 6
- 230000005540 biological transmission Effects 0.000 description 4
- 230000008021 deposition Effects 0.000 description 4
- 230000007547 defect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 238000000985 reflectance spectrum Methods 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000003667 anti-reflective effect Effects 0.000 description 1
- 239000011247 coating layer Substances 0.000 description 1
- 230000000295 complement effect Effects 0.000 description 1
- 238000005566 electron beam evaporation Methods 0.000 description 1
- 125000001475 halogen functional group Chemical group 0.000 description 1
- 238000003331 infrared imaging Methods 0.000 description 1
- 238000000869 ion-assisted deposition Methods 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 239000012788 optical film Substances 0.000 description 1
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Images
Classifications
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- 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
Abstract
The invention relates to a three-way optical filter, comprising: the ultraviolet light filter comprises a transparent base layer, a three-way light filtering film layer and an ultraviolet light cut-off film layer; the three-way light filtering film layer and the ultraviolet light cut-off film layer are formed by alternately stacking and depositing a high-refractive-index material layer and a low-refractive-index material layer. The alternating stacking of the silicon dioxide layer and the titanium pentoxide layer and the alternating stacking of the titanium pentoxide layer and the silicon dioxide layer enable the silicon dioxide layer to have three pass bands, so that the silicon dioxide layer can be simultaneously applied to two infrared wavelengths, the human face and iris recognition modes can be used together, and the recognition accuracy is greatly improved. In addition, due to the adoption of the RGB + IR sensor technology, the camera assembly and the infrared sensing assembly can be integrated together, 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 film-coated optical filters, in particular to a three-way optical filter and a biological identification system thereof.
Background
Face recognition and other advanced biometric technologies are becoming more prevalent in mobile devices and notebook computers, increasingly replacing digital passwords and fingerprint authentication. With the advent of RGB + IR sensors, which can comprehensively support color and infrared imaging applications and can reduce overall system cost, IR-based biometric recognition capabilities can also be provided for face recognition and gesture interfaces for a range of devices, including smart phones, tablets, laptops, etc. Meanwhile, the imaging device with the integrated design can reduce the requirement on the equipment space and meet the aesthetic industrial design. The double-pass filter can cut off infrared light and highly transmit visible light, and the photographing performance of the camera component is improved. But also can penetrate a part of infrared light required by the infrared sensor, thereby realizing the function of biological identification.
In order to improve the accuracy of biometric identification using the RGB + IR sensor scheme, a plurality of light sources may be used to emit light in different wavelength bands to extract the characteristics of different organs of the object to be identified. Typical examples of the method include identification, which uses 850nm band for iris feature recognition and 960nm band for face feature recognition, however, there is no filter that can transmit light of these two infrared bands simultaneously. Therefore, there is a need in the art for a solution with three pass bands that can simultaneously transmit light in the two infrared bands and simultaneously transmit visible light.
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 which can simultaneously transmit light and visible light required by iris feature recognition and face feature recognition exists at present.
In order to achieve the purpose, the invention provides the following scheme:
a three-way filter, the filter comprising:
a transparent base layer;
the three-way light filtering film layer and the ultraviolet light cut-off film layer are respectively plated on two sides of the transparent base layer;
the three-way light filtering film layer and the ultraviolet light cut-off film layer are formed by alternately stacking and depositing a high-refractive-index material layer and a low-refractive-index material layer.
A three-way filter, the filter comprising:
a transparent base layer;
the ultraviolet light cut-off three-way light filtering film layer is 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 three-way light filtering film layer and the anti-reflection film layer are formed by alternately stacking and depositing a high-refractive-index material layer and a low-refractive-index material layer.
Optionally, the transparent base layer is made of one of glass, an acrylic plate and a film, and the thickness of the transparent base layer is 0.2-0.5 mm.
Optionally, the high refractive index material layer is made of at least one of trititanium 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 light filtering 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 light filtering film layer, the thickness of each single layer of the titanium pentoxide layer is 1-400 nm, and the thickness of each single layer of the 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 thickness of each titanium pentoxide layer is 1-200 nm, and the thickness of each silicon dioxide layer is 1-300 nm.
Optionally, the three-way filter suppresses light with a wavelength from a first wavelength to a second wavelength, light with a wavelength from a third wavelength to a fourth wavelength, light with a wavelength from a fifth wavelength to a sixth wavelength, and light with a wavelength greater than a 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 waveband, the second wavelength belongs to an ultraviolet light or visible light waveband, the third wavelength belongs to a visible light waveband, and the fourth wavelength, the fifth wavelength, the sixth wavelength and the seventh wavelength belong to a near-infrared light waveband;
the first passband of the three-way optical 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 apparatus, the apparatus comprising: the system comprises an optical lens, a three-way optical filter, an image sensor and an image signal processor;
after sequentially passing through the optical lens and the three-way optical filter, the optical signal is read by the image sensor and then transmitted to the image signal processor for processing;
the three-way filter is used for filtering and only allowing light in a visible light long band and a set infrared wavelength band to pass through;
the image sensor is an RGB + IR image sensor and is used for acquiring light transmitted by the three-way filter to obtain a light image array;
the image signal processor is used for filtering the infrared signals in the optical image array when the infrared signals are not needed; when a specific infrared signal is required, the specific infrared signal in the optical image array is reserved.
A biometric identification system, the system comprising:
the three-way filter is used for filtering and only allowing light in a visible light long band and a set infrared wavelength band to pass through;
the RGB + IR image sensor is used for acquiring light transmitted by the three-way filter to obtain a light image array;
the data separation unit is used for separating a black-and-white image data stream and an 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 of a display.
A biometric method, the method comprising:
filtering by using a three-way optical filter, and only allowing light in a visible light long band and a set infrared wavelength band to pass;
acquiring light transmitted by the three-way filter by using an RGB + IR image sensor to obtain a light image array;
separating a black-and-white image data stream and an RGB image data stream in the optical image array;
performing biometric identification using the black and white image data stream;
and 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 the silicon dioxide layers and the titanium pentoxide layers, and the three-way filter is formed by alternately stacking the titanium pentoxide layers and the silicon dioxide layers from bottom to top after the ultraviolet light cut-off film layers are formed, so that the three-way filter is formed by sequentially stacking the three-way filter, the transparent base layer and the ultraviolet light cut-off film layers, visible light with the wavelength of 440 plus 630nm and infrared light with the wavelength of about 850nm and 960nm, and the average transmittance is greater than 95%; the ultraviolet light with the wavelength of 350-410nm and the infrared light with the wavelengths of 670-810nm, 890-920nm and 1000-1100nm are cut off, and the average transmittance is less than 3 percent.
The biological recognition system designed by the three-way optical filter can be simultaneously applied to two infrared wavelengths, realizes the combination of human face and iris recognition modes, and greatly improves the recognition accuracy. In addition, due to the adoption of the RGB + IR sensor technology, the camera assembly and the infrared sensing assembly can be integrated together, 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 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 it is obvious for those skilled in the art to obtain other drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a three-way filter according to an embodiment of the present invention.
Fig. 2 is a transmittance spectrum of the ultraviolet light cut-off film of the three-way filter according to the first embodiment of the present invention.
Fig. 3 is a transmittance spectrum of a three-way filter film layer of the three-way filter according to the first embodiment of the present invention.
Fig. 4 is a transmittance spectrum of the three-way filter according to the first 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 the anti-reflection film layer of the three-way filter according to the second embodiment of the present invention.
Fig. 7 is a transmittance spectrum of the three-way filter according to the second embodiment of the present invention.
Fig. 8 is a schematic structural diagram of a biometric imaging apparatus according to a third embodiment of the present invention.
Fig. 9 is a schematic diagram of the three-way filter of the biometric imaging apparatus according to the third embodiment of the invention for suppressing the incident light band.
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 of a basic operation mode of the biometric authentication system according to the fourth embodiment of the present invention.
Fig. 12 is a schematic diagram illustrating a control method of a biometric identification system according to a fourth embodiment of the present invention.
Description of the symbols:
10. 11-a transparent base layer; 20-three-way light filtering film layer; 30-an ultraviolet light cut-off film layer; 21-ultraviolet light cut-off three-way light filtering film layer; 31-an anti-reflective film layer; 301-an optical lens; 302-a three-way filter; 303-an image sensor; 304-an image signal processor; m1-three-way filter; M2-RGB + IR image sensor; m3-data separation unit; m4-recognition unit; m5-display element.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention aims to provide a three-way optical filter and a biological recognition system thereof, which solve the defect that no optical filter which can simultaneously transmit light and visible light required by iris feature recognition and face feature recognition exists at present.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.
The first embodiment is as follows:
as shown in fig. 1, an embodiment of the present invention provides a three-way filter, including:
a transparent base layer 10;
a three-way light filtering film layer 20 and an ultraviolet light cut-off film layer 30 respectively plated on both sides of the transparent base layer 10; the transmittance spectrum of the uv-cut film 30 is shown in fig. 2, and the transmittance spectrum of the three-way filter film 20 is shown in fig. 3.
The transparent base layer 10 is made of one of glass, acrylic plates and films, and the thickness of the transparent base layer is 0.2-0.5 mm; the preferred material model is Schottky white glass (model: D263T eco), the thickness includes but is not limited to 0.03-2 mm, and the preferred thickness is 0.2-0.5 mm.
The three-way light filtering film layer 20 and the ultraviolet light cut-off film layer 30 are formed by alternately stacking and depositing 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 trititanium pentoxide layer; the total number of the silicon dioxide layer and the titanium pentoxide layer is 50-200; in the three-way light filtering film layer, the thickness of each single titanium pentoxide layer is 1-400 nm, and the thickness of each single 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 thickness of each titanium pentoxide layer is 1-200 nm, and the thickness of each silicon dioxide layer is 1-300 nm.
The three-way optical filter provided by the embodiment of the invention inhibits 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 larger 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 waveband, the second wavelength belongs to an ultraviolet light or visible light waveband, the third wavelength belongs to a visible light waveband, and the fourth wavelength, the fifth wavelength, the sixth wavelength and the seventh wavelength belong to a near-infrared light waveband;
the first passband of the three-way optical 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 transmission rate of the passband of the three-way optical filter is more than 95 percent, and the average transmission rate of the cutoff band is less than 3 percent; the three-way optical filter is applied to an imaging device and a biological identification 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 oxide layer, the third layer is a silicon dioxide layer, the fourth layer is a titanium oxide layer … …, the layers are stacked alternately in sequence, and the last layer is a silicon dioxide layer. Wherein, the total number of layers of the silicon dioxide layer and the titanium pentoxide layer is 129. The total number of silica layers was 65 layers and the total number of trititanium pentoxide layers was 64 layers, see table 1.
Table 1: three-way light filtering film layer 20 each layer material and film thickness meter
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 oxide layer, the second layer is a silicon dioxide layer, the third layer is a titanium oxide layer, the fourth layer is a silicon dioxide layer … …, the layers are stacked alternately in sequence, and the last layer is a silicon dioxide layer. The total number of the titanium pentoxide layers and the silicon dioxide layers was 20, and the total number of the titanium pentoxide layers and the silicon dioxide layers was 10, respectively, as shown in table 2.
Table 2: each layer material and film thickness of the ultraviolet light cut-off film layer 30
The deposition of the titanium pentoxide layer and the silicon dioxide layer adopts electron beam evaporation and ion-assisted deposition, the thickness control method adopts an extreme method for 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 the silicon dioxide is less than 12A/S, and the ion source current is 600-1500 mA; the vacuum degree during deposition is 1.0x10-2～1.6x10-2pa。
In addition, the three-way filter provided by the embodiment of the present invention may further include 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 adopts the silicon dioxide layer and the titanium pentoxide layer which are alternately stacked to form the three-way filtering film layer 20, and after the titanium pentoxide layer and the silicon dioxide layer are alternately stacked to form the ultraviolet light cut-off film layer 30, the three-way filtering 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 the light can pass through the visible light with the wavelength of 440 and 630nm and the infrared light with the specified wavelength range near 850nm and 960nm, and the average transmittance is greater than 95 percent; the ultraviolet light with the wavelength of 350-410nm and the infrared light with the wavelengths of 670-810nm, 890-920nm and 1000-1100nm are cut off, the average transmittance is less than 3 percent, the transmittance spectrogram (the incident angle is 0 ℃) is shown in figure 4, and the filtering characteristic data is shown in the following tables 3 and 4.
Table 3: the embodiment of the invention provides data of the passband filtering characteristics of the three-way optical filter
Table 4: the first embodiment of the invention provides the data of the filter characteristics of the cut-off band of the three-way filter
Wherein the first passband is a visible passband, the wavelength is 430nm to 640nm, and the FWHM (FullWidth At Half maximum) is 210 nm; the second passband is a near infrared passband, the wavelength is 825nm to 875nm, and the FWHM is 50 nm; the third passband is a near infrared passband, the wavelength is 935nm to 985nm, and the FWHM is 50 nm; the three do not overlap. Within the pass band, the average transmittance of the optical filter is more than 97 percent; outside the pass band (cut-off band), the transmission of the filter is on average less than 2%. Therefore, the three-way optical filter provided by the embodiment of the invention can be applied to a biological identification system simultaneously applying a plurality of wavelengths, has high peak transmittance and deeper cut-off, inhibits halo and temperature drift, and further effectively improves the identification accuracy.
Example two:
as shown in fig. 5, the embodiment of the present invention provides a three-way filter, which is different from the other embodiments in that the filter includes a transparent base layer 11, an ultraviolet cut three-way filter film layer 21 disposed on the upper surface of the transparent base layer 11, and an anti-reflection film layer 31 disposed on the lower surface of the transparent base layer 11. The reflectance spectrum of the anti-reflection film layer 31 is shown in fig. 6.
The ultraviolet light cut-off three-way light filtering film layer 21 is formed by alternately stacking a silicon dioxide layer and a trititanium pentoxide layer; the first layer is a silicon dioxide layer, the second layer is a titanium oxide layer, the third layer is a silicon dioxide layer, the fourth layer is a titanium oxide layer … …, the layers are stacked alternately in sequence, and the last layer is a silicon dioxide layer. The total number of the silicon dioxide layers and the titanium pentoxide layers is 143, the total number of the silicon dioxide layers is 72, and the total number of the titanium pentoxide layers is 71, as shown in table 5.
Table 5: three-way light filtering film layer 21 each layer material and film thickness meter
The antireflection film layer 31 is a broadband antireflection film layer composed of a titanium pentoxide layer and a silicon dioxide layer which are alternately stacked; the first layer is a titanium oxide layer, the second layer is a silicon dioxide layer, the third layer is a titanium oxide layer, the fourth layer is a silicon dioxide layer … …, the layers are stacked alternately in sequence, and the last layer is a silicon dioxide layer. The total number of the titanium pentoxide layers and the silicon dioxide layers was 8, and the total number of the titanium pentoxide layers and the silicon dioxide layers was 4, respectively, as shown in table 6.
Table 6: material and thickness of each layer of antireflection film layer 31
The three-way filter provided by the embodiment of the invention adopts the silicon dioxide layer and the titanium pentoxide layer which are alternately stacked to form the ultraviolet light cut-off three-way filter film layer 21, adopts the titanium pentoxide layer and the silicon dioxide layer which are alternately stacked to form the anti-reflection film layer 31, and sequentially forms the three-way filter from top to bottom by the ultraviolet light cut-off three-way filter film layer 21, the transparent base layer 11 and the anti-reflection film layer 31, thereby passing through the visible light with the wavelength of 440 and 630nm and the infrared light with the specified wavelength range of 850nm and 960nm, and the average transmittance is more than 95 percent; the ultraviolet light with the wavelength of 350-410nm and the infrared light with the wavelengths of 670-810nm, 890-920nm and 1000-1100nm are cut off, the average transmittance is less than 3 percent, the transmittance spectrogram (the incident angle is 0 ℃) is shown in figure 7, and the filtering characteristic data is shown in the following table 7 and 8.
Table 7: the second embodiment of the invention provides the data of the passband filtering characteristics of the three-way optical filter
Table 8: the second embodiment of the invention provides the data of the filter characteristics of the cut-off band of the three-way filter
Wherein the first passband is a visible passband, the wavelength is 430nm to 640nm, and the FWHM (FullWidth At Half maximum) is 210 nm; the second passband is a near infrared passband, the wavelength is 825nm to 875nm, and the FWHM is 50 nm; the third passband is a near infrared passband, the wavelength is 935nm to 985nm, and the FWHM is 50 nm; the three do not overlap. Within the pass band, the average transmittance of the optical filter is greater than 96.4%; outside the pass band (cut-off band), the transmission of the filter is on average less than 2%. Therefore, the three-way optical filter can be applied to a biological identification system simultaneously applying a plurality of wavelengths, has high peak transmittance and deeper cut-off, inhibits halation and temperature drift, and further effectively improves the identification accuracy.
Example three:
referring to fig. 8, an embodiment of the present invention provides a biometric imaging apparatus, which is different from the other embodiments in that the apparatus includes: 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 a three-way filter provided in the first embodiment or the second embodiment.
After passing through the optical lens 301 and the three-way filter 302 in sequence, the optical signal is read by the image sensor 303 and then transmitted to the image signal processor 304 for processing;
the three-way filter 302 is used for filtering and only allowing light in a visible light long band and a set infrared wavelength band to pass through, as shown in fig. 9;
a three-way filter 302 is disposed between the optical lens 301 and the image sensor 303, the three-way filter 302 being configured to suppress light having a wavelength between a first wavelength and a second wavelength, and light having a wavelength between a third wavelength and a fourth wavelength, and light having a fifth wavelength and a sixth wavelength, and light having a wavelength greater than a seventh wavelength, from 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 wavelength and the fifth wavelength and the sixth wavelength and the seventh wavelength belong to the near-infrared light band.
It can be understood that the wavelength band between the second wavelength and the third wavelength includes a visible light wavelength band, which belongs to the wavelength band to be collected by the imaging device, and an ultraviolet wavelength band to be filtered out for the wavelength band between the first wavelength and the second wavelength. The wave band from the third wavelength to the fourth wavelength, the wave band from the fifth wavelength to the sixth wavelength, the wave band larger than the seventh wavelength belong to the near-infrared wave band needing filtering, and the wave band between the fourth wavelength and the seventh wavelength belongs to the selectively filtered near-infrared wave band.
In 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 1050 nm.
The image sensor 303 is an RGB + IR image sensor, which can simultaneously implement white light RGB capture and specific infrared light capture in a single CMOS (Complementary Metal Oxide Semiconductor) image sensor, and is configured to acquire light transmitted by the three-way filter to obtain a light image array;
the image signal processor 304 is configured to filter out the infrared signal in the optical image array when the infrared signal is not needed; when a specific infrared signal is required, 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 passbands, and infrared light of two passbands is adopted, so that the device can be applied to a biological identification system simultaneously applying a plurality of wavelengths, 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 assembly and the infrared sensing assembly can be integrated together, the internal space of the electronic equipment can be effectively saved, and the production cost is greatly reduced.
Example four:
referring to fig. 10, an embodiment of the present invention provides a biometric identification system, a specific operation mode of which is shown in fig. 11, and the biometric identification system includes:
the three-way filter M1 is used for filtering and only allowing the light in the visible light wavelength band and the set infrared wavelength band to pass; filtering by using a three-way filter M1, and only allowing light in a color wavelength band and a set infrared wavelength band to pass; the light source has high transmittance to RGB light, high transmittance to near infrared light with specific wavelength of 730-1100 nm, and no transmittance to other near infrared light. The currently used image sensor generally has a good imaging effect on near infrared light, and near infrared light with a wavelength of 730 to 1100nm, such as infrared wavelengths of 850nm, 960nm, 1000nm, etc., is used here.
The RGB + IR image sensor M2 is used for acquiring light transmitted by the three-way filter to obtain a light 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 for separating 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 the 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 biometric identification using the black and white image data stream;
a display unit M5 for processing the RGB image data stream for display by a display.
The embodiment of the present invention further provides a biometric identification method, please refer to fig. 12, where the method includes:
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, carrying out biological identification by using the black-and-white image data stream;
and S5, processing the RGB image data stream for display of a display.
The biological recognition system provided by the embodiment of the invention utilizes the three-way optical filter, and can pass light of three passbands, and infrared light of two passbands is adopted, so that the device can be applied to a biological recognition system simultaneously applying a plurality of wavelengths, 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 combination of a face and iris recognition mode, and greatly improves the recognition accuracy. In addition, the RGB + IR sensor technology is adopted, so that the camera assembly and the infrared sensing assembly can be integrated, the internal space of the electronic equipment can be effectively saved, and the production cost is greatly reduced
In the present specification, the emphasis points of the embodiments are different from those of the other embodiments, and the same and similar parts among the embodiments may be referred to each other.
The principles and embodiments of the present invention have been described herein using specific examples, which are provided only to help understand the method and the core concept of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.
Claims (10)
1. A three-way filter, comprising:
a transparent base layer;
the three-way light filtering film layer and the ultraviolet light cut-off film layer are respectively plated on two sides of the transparent base layer;
the three-way light filtering film layer and the ultraviolet light cut-off film layer are formed by alternately stacking and depositing a high-refractive-index material layer and a low-refractive-index material layer.
2. A three-way filter, comprising:
a transparent base layer;
the ultraviolet light cut-off three-way light filtering film layer is 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 three-way light filtering film layer and the anti-reflection film layer are formed by alternately stacking and depositing a high-refractive-index material layer and a low-refractive-index material layer.
3. The three-way filter according to claim 1 or 2, wherein the transparent substrate is made of one of glass, acrylic plate and film, and has a thickness of 0.2-0.5 mm.
4. The three-way filter according to claim 1 or 2, wherein the high refractive index material layer is composed of at least one of trititanium 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.
5. The three-way filter according to claim 1, wherein 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 light filtering film layer, the thickness of each single layer of the titanium pentoxide layer is 1-400 nm, and the thickness of each single layer of the silicon dioxide layer is 1-1000 nm.
6. The three-way filter according to claim 1, wherein the ultraviolet light cut 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 thickness of each titanium pentoxide layer is 1-200 nm, and the thickness of each silicon dioxide layer is 1-300 nm.
7. The three-way filter according to claim 1 or 2,
the three-way optical filter inhibits 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 larger 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 waveband, the second wavelength belongs to an ultraviolet light or visible light waveband, the third wavelength belongs to a visible light waveband, and the fourth wavelength, the fifth wavelength, the sixth wavelength and the seventh wavelength belong to a near-infrared light waveband;
the first passband of the three-way optical 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.
8. A biometric imaging apparatus, the apparatus comprising: an optical lens, the three-way filter of claim 1 or 2, an image sensor and an image signal processor;
after sequentially passing through the optical lens and the three-way optical filter, the optical signal is read by the image sensor and then transmitted to the image signal processor for processing;
the three-way filter is used for filtering and only allowing light in a visible light long band and a set infrared wavelength band to pass through;
the image sensor is an RGB + IR image sensor and is used for acquiring light transmitted by the three-way filter to obtain a light image array;
the image signal processor is used for filtering the infrared signals in the optical image array when the infrared signals are not needed; when a specific infrared signal is required, the specific infrared signal in the optical image array is reserved.
9. A biometric identification system, the system comprising:
the three-way filter is used for filtering and only allowing light in a visible light long band and a set infrared wavelength band to pass through;
the RGB + IR image sensor is used for acquiring light transmitted by the three-way filter to obtain a light image array;
the data separation unit is used for separating a black-and-white image data stream and an 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 of a display.
10. A biometric identification method, the method comprising:
filtering by using a three-way optical filter, and only allowing light in a visible light long band and a set infrared wavelength band to pass;
acquiring light transmitted by the three-way filter by using an RGB + IR image sensor to obtain a light image array;
separating a black-and-white image data stream and an RGB image data stream in the optical image array;
performing biometric identification using the black and white image data stream;
and processing the RGB image data stream for display by a display.
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