A multispectral fingerprinting device
By using a bandpass filter and a diffraction focusing lens in a multispectral fingerprint recognition device to divide the image acquisition module into multiple regions, the problem of excessively long recognition time caused by sequential lighting of the light source module in the prior art is solved, enabling simultaneous multi-band fingerprint recognition and shortening the recognition time.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- TRULY OPTO-ELECTRONICS TECH LTD
- Filing Date
- 2025-06-26
- Publication Date
- 2026-07-14
AI Technical Summary
In existing multispectral fingerprint recognition devices, the light source module needs to sequentially illuminate light sources of different wavelengths, resulting in an excessively long fingerprint recognition process.
The photosensitive area of the image acquisition module is divided into multiple image acquisition areas by using a bandpass filter and a diffraction focusing lens. A bandpass filter and a diffraction focusing lens are also set in front of the image acquisition module to perform partitioned diffraction focusing and filtering processing on light beams of different wavelengths, so that the image acquisition module can simultaneously acquire fingerprint images in various wavelengths.
It enables simultaneous multi-band fingerprint recognition, shortening the recognition time.
Smart Images
Figure CN224501294U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to fingerprint recognition technology, and more particularly to a multispectral fingerprint recognition device. Background Technology
[0002] Multispectral fingerprint recognition technology uses light of different wavelengths (such as visible light, infrared light, and ultraviolet light) to illuminate fingerprints. Because the fingerprint ridges (such as ridges and valleys), skin tissue, sweat composition, and underlying substances (such as oils and moisture) react differently to different wavelengths of light, a unique spectral image is formed. By combining the characteristic differences of fingerprints under different spectra, a more comprehensive fingerprint template can be constructed. For example, infrared light can penetrate the skin surface to obtain the vascular structure of subcutaneous tissue or deep fingerprint information; ultraviolet light is more sensitive to certain components in sweat and can enhance fingerprint contrast.
[0003] For example, Chinese Patent Application No. CN201910263378.3 discloses a multispectral live fingerprint recognition device, including a flat glass, a light source module, an image acquisition module, and a control module. The light source module is used to provide light in multiple different wavelength bands. The control module is used to sequentially select light of each wavelength band to illuminate the flat glass according to a preset time sequence. The image acquisition module is used to acquire fingerprint images of the target on the flat glass under each wavelength band and send them to the control module. The control module is also used to perform fingerprint recognition based on the fingerprint images, synthesize the fingerprint images into a multispectral image for analysis, obtain the spectral function of the target fingerprint, and determine whether the target fingerprint is a real fingerprint based on the spectral function of the target fingerprint.
[0004] However, the light source module integrates multiple light sources of different wavelengths, while the image acquisition module has only one. Therefore, the light source module needs to light up the light sources of each wavelength in chronological order so that the image acquisition module can acquire fingerprint images of each wavelength in chronological order. This will undoubtedly lead to a longer fingerprint recognition process. Utility Model Content
[0005] To address the shortcomings of the existing technology, this invention provides a multispectral fingerprint recognition device that can shorten the fingerprint recognition time across multiple bands.
[0006] The technical problem to be solved by this utility model is achieved through the following technical solution:
[0007] A multispectral fingerprint recognition device, comprising:
[0008] The light source module includes multiple light sources in different wavelength bands;
[0009] An image acquisition module is located next to the light source module and includes multiple image acquisition areas, with each acquisition area corresponding to a light source of one wavelength band.
[0010] A bandpass filter is disposed in front of the image acquisition module and includes multiple bandpass filter areas, with each bandpass filter area corresponding to an image acquisition area and a light source of one wavelength.
[0011] A diffraction focusing lens is disposed in front of the bandpass filter and has multiple diffraction focusing areas, with each diffraction focusing area corresponding to an image acquisition area.
[0012] Furthermore, the diffraction focusing lens has diffraction focusing microstructures on the surface of each diffraction focusing region.
[0013] Furthermore, the diffraction focusing microstructure is a Fresnel lens microstructure or a phase waveband microstructure.
[0014] Furthermore, the light source is an LED light source.
[0015] Furthermore, the light source module includes at least one infrared light source and one visible light source.
[0016] Furthermore, the light source module includes at least one light source in the ultraviolet band and one light source in the visible light band.
[0017] Furthermore, the light source module includes at least one light source in the infrared band, one light source in the ultraviolet band, and one light source in the visible band.
[0018] Furthermore, the multispectral fingerprint recognition device also includes:
[0019] A finger placement panel is positioned in front of the light source module and the diffraction focusing lens.
[0020] Furthermore, the finger placement panel is a flat glass panel or a display panel.
[0021] Furthermore, the diffraction focusing lens is integrated on the side surface of the finger placement panel facing the bandpass filter.
[0022] This invention has the following advantages: The multispectral fingerprint recognition device of this invention divides the entire photosensitive area of the image acquisition module into multiple image acquisition areas, and sequentially arranges the bandpass filter and diffraction focusing lens in front of the image acquisition module. Each diffraction focusing area of the diffraction focusing lens is responsible for partitioning and focusing the multi-band mixed beam emitted by the light source module and reflected by the finger surface to form multiple focused beams. Each bandpass filtering area of the bandpass filter is responsible for filtering other bands in each focused beam except for the corresponding band, so that each image acquisition area of the image acquisition module can acquire the fingerprint image under the corresponding band. In this way, the light source module can simultaneously light up the light source of each band, so that the image acquisition module can simultaneously acquire fingerprint images under each band, thereby shortening the fingerprint recognition time under multiple bands. Attached Figure Description
[0023] Figure 1 This is a schematic diagram of the structure of the multispectral fingerprint recognition device provided by this utility model.
[0024] Figure 2 A schematic diagram showing the distribution of each bandpass filter region in the multispectral fingerprint recognition device provided by this utility model.
[0025] Figure 3 This is a schematic diagram showing the distribution of various diffraction focusing regions of the diffraction focusing lens in the multispectral fingerprint recognition device provided by this utility model. Detailed Implementation
[0026] The present invention will now be described in detail with reference to the accompanying drawings and embodiments, examples of which are shown in the drawings. Throughout the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.
[0027] In the description of this utility model, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.
[0028] Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first," "second," or "third" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "multiple" means two or more, unless otherwise explicitly specified.
[0029] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," "fixing," and "setting," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.
[0030] Example 1
[0031] A multispectral fingerprint recognition device, comprising:
[0032] Light source module 1 includes multiple light sources 11 of different wavelengths;
[0033] Image acquisition module 2 is located next to the light source module 1 and includes multiple image acquisition areas 21, with each acquisition area corresponding to a light source 11 of a certain wavelength.
[0034] A bandpass filter 3 is disposed in front of the image acquisition module 2 and includes multiple bandpass filter areas 31. Each bandpass filter area 31 corresponds to an image acquisition area 21 and a light source 11 of one wavelength.
[0035] The diffraction focusing lens 4 is disposed in front of the bandpass filter 3 and has multiple diffraction focusing areas 41, with each diffraction focusing area 41 corresponding to an image acquisition area 21.
[0036] The multispectral fingerprint recognition device of this invention divides the entire photosensitive area of the image acquisition module 2 into multiple image acquisition areas 21. A bandpass filter 3 and a diffraction focusing lens 4 are sequentially arranged in front of the image acquisition module 2. Each diffraction focusing area 41 of the diffraction focusing lens 4 is responsible for partitioning and focusing the multi-band mixed beam emitted by the light source module 1 and reflected by the finger surface to form multiple focused beams. Each bandpass filtering area 31 of the bandpass filter 3 is responsible for filtering other bands in each focused beam except for the corresponding band, so that each image acquisition area 21 of the image acquisition module 2 can acquire the fingerprint image under the corresponding band. In this way, the light source module 1 can simultaneously illuminate the light source 11 of each band, allowing the image acquisition module 2 to simultaneously acquire fingerprint images under each band, thereby shortening the fingerprint recognition time under multiple bands.
[0037] The diffraction focusing lens 4 has a diffraction focusing microstructure 42 on the surface of each diffraction focusing region 41. The diffraction focusing microstructure 42 may be, but is not limited to, a Fresnel lens microstructure or a phase waveband microstructure.
[0038] In one example, the light source module 1 includes at least one infrared light source 11 and one visible light source 11.
[0039] Near-infrared light (760~1100nm) can penetrate the skin surface (approximately 0.5~2mm), scattering or absorbing the vascular distribution and collagen fiber structure in the dermis, forming "vascular fingerprints" or "subcutaneous textures." For example, the vascular distribution on the fingertip of a live fingerprint is individual-specific, and infrared imaging can capture deep features such as vascular direction and branching points. Simultaneously, water in skin tissue has a specific absorption spectrum for infrared light, and infrared images can reflect differences in water content within the fingerprint area, aiding in determining the skin's physiological state (e.g., whether the fingerprint is from a living or non-living individual). Visible light (400-760nm), on the other hand, directly reflects the three-dimensional geometric structure of the fingerprint (ridges, valleys, and minutiae), offering high imaging contrast and making it suitable for clearly presenting conventional fingerprint textures. The fusion of infrared and visible light fingerprints can construct a multi-dimensional feature set of "epidermal texture + subcutaneous structure." For instance, for fingerprints covered by wear or scars, visible light may result in texture loss due to epidermal damage, while infrared light can supplement identification through subcutaneous vascular features, reducing the rejection rate.
[0040] In another example, the light source module 1 includes at least one light source 11 in the ultraviolet band and one light source 11 in the visible light band.
[0041] Ultraviolet light (wavelength 10-400nm) has unique excitation or reflection characteristics on fingerprint residues (such as sweat, oil, and amino acids). For example, urea and amino acids in sweat produce weak fluorescence under ultraviolet light, forming "biochemical fingerprints" that are difficult to detect under visible light. This can reveal details of worn or faint fingerprints (such as crack lines and sweat pores). At the same time, ultraviolet light can penetrate some non-transparent surfaces (such as thin plastic and paper) to image fingerprint residues (such as oils that have penetrated into paper fibers), supplementing information that visible light cannot obtain. Visible light (400-760nm) directly reflects the three-dimensional geometric structure of fingerprints (ridges, valleys, and details), with high imaging contrast, suitable for clearly presenting regular fingerprint textures. After fusion of ultraviolet and visible light fingerprints, both "biochemical substance distribution" and "physical texture structure" can be preserved. For aged or contaminated fingerprints, visible light may cause the texture to become blurred due to surface stains, while ultraviolet light can locate the real ridge lines through the fluorescence of residual substances. After fusion, a complete fingerprint pattern can be reconstructed.
[0042] In another example, the light source module 1 includes at least one infrared light source 11, one ultraviolet light source 11, and one visible light source 11.
[0043] Near-infrared light (760~1100nm) can penetrate the skin surface (about 0.5~2mm) and produce scattering or absorption effects on the distribution of blood vessels and collagen fiber structure in the dermis, forming "vascular fingerprints" or "subcutaneous textures". For example, the distribution of blood vessels on the fingertip of a living fingerprint is individual-specific, and infrared imaging can capture deep features such as the direction of blood vessels and branching points. At the same time, the water in the skin tissue has a specific absorption spectrum for infrared light, and infrared images can reflect the differences in water content in the fingerprint area, helping to determine the physiological state of the skin (such as living versus non-living). Ultraviolet light (wavelength 10-400nm) has unique excitation or reflection properties on fingerprint residues (such as sweat, oil, and amino acids). For example, urea and amino acids in sweat produce weak fluorescence under ultraviolet light, forming "biochemical fingerprints" that are difficult to detect under visible light. This can reveal details of worn or faint fingerprints (such as crack lines and sweat pores). At the same time, ultraviolet light can penetrate some non-transparent surfaces (such as thin plastic and paper) to image fingerprint residues that are covered (such as oils that have penetrated into paper fibers), supplementing information that visible light cannot obtain. Visible light (400-760nm), on the other hand, directly reflects the three-dimensional geometric structure of fingerprints (ridges, valleys, and details), with high imaging contrast, making it suitable for clearly presenting regular fingerprint textures. After fusing infrared, ultraviolet, and visible light fingerprints, a three-dimensional feature set of "chemical residue (ultraviolet) + physical texture (visible light) + physiological structure (infrared)" can be constructed. For example, for fingerprints with oil stains, visible light may cause the texture to become blurred due to reflection, ultraviolet light can reveal the outline of the ridges through the fluorescent properties of oil, and infrared light can penetrate the oil stains to obtain the subcutaneous blood vessel features. After fusing the three, complete fingerprint information can be reconstructed.
[0044] Preferably, the light source 11 is an LED light source, and the image acquisition module 2 is a CMOS module or a CCD module.
[0045] The multispectral fingerprint recognition device also includes:
[0046] The finger placement panel 5 is positioned in front of the light source module 1 and the diffraction focusing lens 4.
[0047] The finger placement panel 5 is used for users to place their fingers for fingerprint recognition. The light source module 1 emits a mixed light beam of various wavelengths onto the finger placement panel 5 to illuminate the fingerprint on the finger surface. The image acquisition module 2 acquires the mixed light beam reflected from the finger surface through the bandpass filter 3 and the diffraction focusing lens 4 to simultaneously obtain fingerprint images of various wavelengths.
[0048] The finger placement panel 5 may be, but is not limited to, a flat glass (such as a fingerprint recognition device for terminal devices such as attendance machines and smart door locks) or a display panel (such as a fingerprint recognition device for terminal devices such as mobile phones).
[0049] Preferably, the diffraction focusing lens 4 is integrated on the side surface of the finger placement panel 5 facing the bandpass filter 3, that is, the diffraction focusing microstructures 42 forming each diffraction focusing region 41 of the diffraction focusing lens 4 are directly fabricated on the surface of the finger placement panel 5 by means of laser etching, mask etching or nanoprinting.
[0050] During assembly, the light source module 1 and the image acquisition module 2 can be mounted on the same PCB board, and corresponding mounting brackets can be set on the PCB board to assemble and support the bandpass filter 3, the diffraction focusing lens 4 and the finger placement panel 5.
[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present utility model and not to limit them. Although the present utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present utility model, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the scope of the technical solutions of the present utility model.
Claims
1. A multispectral fingerprint recognition device, characterized in that, include: The light source module includes multiple light sources in different wavelength bands; An image acquisition module is located next to the light source module and includes multiple image acquisition areas, with each acquisition area corresponding to a light source of one wavelength band. A bandpass filter is disposed in front of the image acquisition module and includes multiple bandpass filter areas, with each bandpass filter area corresponding to an image acquisition area and a light source of one wavelength. A diffraction focusing lens is disposed in front of the bandpass filter and has multiple diffraction focusing areas, with each diffraction focusing area corresponding to an image acquisition area.
2. The multispectral fingerprint recognition device according to claim 1, characterized in that, The diffraction focusing lens has diffraction focusing microstructures on the surface of each diffraction focusing region.
3. The multispectral fingerprint recognition device according to claim 2, characterized in that, The diffraction focusing microstructure is a Fresnel lens microstructure or a phase waveband microstructure.
4. The multispectral fingerprint recognition device according to claim 1, characterized in that, The light source is an LED light source, and the image acquisition module is a CMOS module or a CCD module.
5. The multispectral fingerprint recognition device according to claim 1, characterized in that, The light source module includes at least one infrared light source and one visible light source.
6. The multispectral fingerprint recognition device according to claim 1, characterized in that, The light source module includes at least one light source in the ultraviolet band and one light source in the visible light band.
7. The multispectral fingerprint recognition device according to claim 1, characterized in that, The light source module includes at least one infrared light source, one ultraviolet light source, and one visible light source.
8. The multispectral fingerprint recognition device according to claim 1, characterized in that, The multispectral fingerprint recognition device also includes: A finger placement panel is positioned in front of the light source module and the diffraction focusing lens.
9. The multispectral fingerprint recognition device according to claim 8, characterized in that, The finger placement panel is a flat glass panel or a display panel.
10. The multispectral fingerprint recognition device according to claim 8 or 9, characterized in that, The diffraction focusing lens is integrated on the side surface of the finger placement panel facing the bandpass filter.