CN102004912B - Fingerprint acquisition device - Google Patents
Fingerprint acquisition device Download PDFInfo
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- CN102004912B CN102004912B CN 200910171644 CN200910171644A CN102004912B CN 102004912 B CN102004912 B CN 102004912B CN 200910171644 CN200910171644 CN 200910171644 CN 200910171644 A CN200910171644 A CN 200910171644A CN 102004912 B CN102004912 B CN 102004912B
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- fingerprint acquisition
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Abstract
The invention provides a fingerprint acquisition device comprising a light source, a prism, a light detector and an image sensor. The prism has a fingerprint acquisition surface, a reflection surface and an outgoing surface. The light detector is provided with a lens, and reflectors which are respectively arranged between the outgoing surface and the lens and between the lens and the image sensor. Light emitted by the light source is incident upon the prism, and light emitted by the outgoing surface is detected in the observation angle range and transmitted to the image sensor. The reflection surface is not symmetric relative to the observation shaft of the light detector, so that the light exits from one angle of the prism, and the path of light is refracted back to spare space at one side of the prism through the reflection of the reflectors. The fingerprint acquisition device has the advantage of reducing volume, and fitting product miniaturization tendency.
Description
Technical field
The present invention relates to a kind of fingerprint acquisition device, relate in particular to a kind of fingerprint acquisition device with asymmetric light path.
Background technology
Along with the development of science and technology and the enhancing of public security consciousness, except some relatively traditional security fields, fingerprint acquisition device more and more is widely used in portable electronic products, such as notebook computer, mobile phone etc.Fig. 1 (a), 1 (b) are depicted as a kind of fingerprint acquisition device 70 that adopts symmetrical light path design.This fingerprint acquisition device 70 comprises a light source 71, a prism 72, a photodetector 74, and an imageing sensor (not shown).This photodetector 74 comprises a diaphragm 740 and a focusing objective len 741.This prism 72 has fingerprint collecting face 720, one reflectings surface 721 for finger 8 applyings, and an exit facet 722.The light that light source 71 sends is projected to finger 8 through prism 72, and quilt enters prism 72 propagation after being pointed 8 scatterings again.Reflecting surface 721 is projected to exit facet 722 with light, by exit facet 722 outgoing to photodetector 74; The light that enters diaphragm 740 further is focused object lens 741 and focuses on, and is resent to imageing sensor.This reflecting surface 721 is with respect to Observing axis 743 left-right symmetric of this photodetector 74, and namely the straight line that intersects of this reflecting surface 721 and these Observing axis 743 place surface levels is perpendicular to this Observing axis 743; So, photodetector 74 need be located at the centre of exit facet 722 1 sides of prism 72.
Existing this symmetrical beam line structure causes the size of fingerprint acquisition device to be subject to certain restrictions, and fingerprint acquisition device must provide enough large space to guarantee symmetrical light path setting, thereby volume is larger.In addition in applied in any combination in other products, as on the notebook computer time, because of the restriction of symmetrical structure, to the certain restriction of being designed with of integral product, can not the flexible utilization space, be difficult to adapt to product miniaturization and portable requirement.
In view of the above problems, existing fingerprint acquisition device needs further to improve, the demand of the better satisfying the market of ability.
Summary of the invention
The invention provides a kind of fingerprint acquisition device, need not the symmetric space setting, and can take less space; And then when designing, system product can not cause too much restriction in applied in any combination.
The fingerprint acquisition device that the present invention proposes comprises light source, prism, photodetector, and imageing sensor.Prism has the fingerprint collecting face, at least one reflecting surface, and exit facet.The light that light source sends is injected this prism, and this photodetector detects the light that this exit facet penetrates in its view angle scope, and it is transmitted to this imageing sensor.And the reflecting surface that light is reflexed to this exit facet is asymmetric with respect to the Observing axis of this photodetector.
In one embodiment, this at least one reflecting surface and exit facet are plane or curved surface.When this reflecting surface that light is reflexed to this exit facet is the plane, the straight line that itself and this Observing axis place surface level intersects and the friendship of this Observing axis monoclinic phase.When this reflecting surface that light is reflexed to this exit facet is curved surface, tangent line and the friendship of this Observing axis monoclinic phase that the curve that is intersected by this curved surface and this Observing axis place surface level and this Observing axis joining determine.In one embodiment, this at least one reflecting surface is mirror-reflection or total reflection mode.This photodetector comprises camera lens, and this camera lens comprises at least one lens.In another embodiment, this photodetector further comprises at least one catadioptric light path element, and this at least one catadioptric light path element is refrative mirror or right-angle prism.This at least one catadioptric light path element is located between the exit facet and this at least one lens of this prism.This at least one catadioptric light path element is located between these lens and this imageing sensor.
Fingerprint acquisition device of the present invention adopts asymmetrical light channel structure, compares with the fingerprint acquisition device of the symmetrical light path of existing employing, and the light of its reflecting surface reflection can concentrate on a jiao of prism, and the space reduced volume of prism one side that is fully utilized; When using catadioptric light path catadioptric, more can fully represent this advantage.And during in system product, can adjust flexibly as required light path effectively reduces product to adapt to excess room size in applied in any combination.
Description of drawings
Fig. 1 (a), 1 (b) are the work synoptic diagram of an existing fingerprint acquisition device;
Fig. 2,3, the 4th, according to an embodiment of the invention the work synoptic diagram of fingerprint acquisition device;
Fig. 5, the 6th, according to another embodiment of the present invention the work synoptic diagram of fingerprint acquisition device;
Fig. 7 is the work synoptic diagram according to the fingerprint acquisition device of further embodiment of this invention.
Reference numeral:
6 fingers, 60 fingerprint ridge, 61 fingerprint paddy;
7 media;
10,20,30 fingerprint acquisition devices;
11,21 light sources;
The light that 110 light sources send;
111 by the light of fingerprint paddy scattering;
112 by the light of fingerprint ridge scattering;
Φ
Max1, Φ
Max2Maximum refraction angle
12,22,32 prisms;
120 fingerprint collecting faces;
121,221 reflectings surface;
122,322 exit facets;
14,24,34 photodetectors;
140,240 Observing axis;
The θ view angle;
15,25,35 imageing sensors;
23 catadioptric light path elements;
241,341 lens;
245 optical axises;
70 fingerprint acquisition devices;
71 light sources;
72 prisms;
720 fingerprint collecting faces;
721 reflectings surface;
722 exit facets
74 photodetectors;
740 diaphragms;
741 focusing objective lens;
743 Observing axis
8 fingers
Embodiment
For ease of better understanding spirit of the present invention, below in conjunction with the preferred embodiments of the present invention it is described further.
Fig. 2,3 is the work synoptic diagram of according to an embodiment of the invention fingerprint acquisition device 10, and wherein Fig. 2 is the work of the overlooking synoptic diagram of this fingerprint acquisition device 10, and Fig. 3 is the side-looking work synoptic diagram of this fingerprint acquisition device 10.
Shown in Fig. 2,3, fingerprint acquisition device 10 adopts asymmetrical light channel structure, comprises a light source 11, a prism 12, a photodetector 14, and an imageing sensor 15.Light source 11 can optionally be positioned over below or the side of prism 12, and the ray cast of its emission is in prism 12 and further be incident upon the finger of fingerprint to be collected through prism 12.This prism 12 can be glass or plastic material, has one and supplies fingerprint collecting face 120, a reflecting surface 121 of the finger placement of fingerprint to be collected, and an exit facet 122.This photodetector 14 has a view angle θ, collects light by exit facet 122 outgoing of prism 12 with this view angle θ, and it is transmitted to image inductor 15.The reflecting surface 121 of this prism 12 is the plane in the present embodiment, and its Observing axis 140 with respect to this photodetector 14 is asymmetric, and namely reflecting surface 121 and straight line and this Observing axis 140 out of plumb that Observing axis 140 place surface levels intersect are that monoclinic phase is handed over.Photodetector 14 is the camera lenses that comprise lens in the present embodiment, thereby Observing axis 140 is the optical axis of lens.Image inductor 15 receives the light of photodetector 14 propagation and generates corresponding fingerprint image.
As shown in Figure 4, usually, the fingerprint shape of finger 6 is made of with fingerprint paddy 61 a series of fingerprint ridge 60, when the finger 6 of fingerprint to be collected is positioned on the fingerprint collecting face 120 of this prism 12, fingerprint ridge 60 contacts with this fingerprint collecting face 120,120 in the fingerprint collecting face of fingerprint paddy 61 and this prism 11 is filled with a medium 7, is generally air or water, and present embodiment is chosen as air.And light can reflect when entering a second medium by a first medium; Wherein in the refractive index of first medium during greater than the second medium refractive index, the incident angle that causes 90 ° of refraction angles is critical angle.When the incident angle of incident light during greater than critical angle, this incident light will be by total internal reflection.According to Snell's law (Snell law):
n1?sinΦ1＝n2?sinΦ2；
Wherein n1 is the refraction coefficient of first medium, and n2 is the refraction coefficient of second medium, and Φ 1 is incident angle, and Φ 2 is the refraction angle.The refraction coefficient of air is generally 1, and the refraction coefficient of pointing 6 fingerprint ridge 60 and prism 12 (usually selecting glass or plastics) is all greater than air.
Thereby the light 110 that light source 11 sends is incident on this prism 12 at a certain angle, and when further exposing to fingerprint ridge 60 with fingerprint paddy 61, wherein by the light 112 of fingerprint ridge 60 scatterings when entering prism 11 and propagate, its maximum refraction angle Φ
Max1The critical angle of corresponding finger 60 and prism 12 interfaces; By the light 111 of fingerprint paddy 61 scatterings when again entering prism 12 and propagate, its maximum refraction angle Φ
Max2The critical angle of corresponding air 7 and prism 12 interfaces; And Φ
Max1＞Φ
Max2The position of light source 11 and prism 12 suitably is set, so that by fingerprint ridge 60 scatterings and enter in the refracted ray of prism 12 most refraction angles greater than the critical angle of air 7 with prism 12 interfaces.The view angle θ of photodetector 14 is set to only receive refraction angle in the refracted ray that is projected on the reflecting surface 121 greater than the critical angle of air 7 with prism 12 interfaces, i.e. maximum refraction angle Φ
Max2, part light, to guarantee only to be received from the light of fingerprint ridge 60 scatterings, get rid of the light from 61 scatterings of fingerprint paddy.Photodetector 14 focuses on the light of collecting and further is projected to imageing sensor 15, such as charge coupled device ccd (Charge CoupledDevice) or the upper imaging of complementary metal oxide semiconductor (CMOS) CMOS (ComplementaryMetal-Oxide-Semiconductor).The fingerprint image that so obtains, corresponding fingerprint ridge 60 are bright stripeds; Corresponding fingerprint paddy 61 and else point the zone of 6 discontiguous fingerprint collecting faces 120 does not form respectively dark striped and dark background because receiving light; Thereby can collect bright fingerprint ridge 60 images and complete clear fingerprint of deceiving fingerprint paddy 61 images with high-contrast.
From Fig. 2,3, can obviously see, because the present invention adopts asymmetrical light channel structure, reflecting surface 121 and camera lens transverse pitch as photodetector 14, the light of its reflection concentrates on a side of prism 12, obviously different from traditional symmetrical light path, need not enough large space and guarantee to be symmetrical arranged, further reduce product size.And this reflecting surface 121 can adjust according to the global design needs of this finger print detection device 10, so that light in the outgoing of corresponding position, greatly improves the dirigibility of product design.
Fig. 5, the 6th, the work synoptic diagram of fingerprint acquisition device 20 according to another embodiment of the present invention, wherein Fig. 5 is the work of the overlooking synoptic diagram of this fingerprint acquisition device 20, Fig. 6 is the side-looking work synoptic diagram of this fingerprint acquisition device 20.
Shown in Fig. 5,6, the asymmetrical fingerprint acquisition device 20 of this light path further adopts catadioptric light path size reduction.This fingerprint acquisition device 20 comprises a light source 21, a prism 22, a photodetector 24, and an imageing sensor 25.The reflecting surface 221 of this prism 22 is curved surfaces in the present embodiment, and such as sphere or aspheric surface, it can form the object space telecentric beam path, and helps diverse location collects on the fingerprint collecting face 220 fingerprint that the image quality of uniformity is arranged.Photodetector 24 comprises lens 241, and the catadioptric element 23 of at least one light path, such as refrative mirror or right-angle prism etc.The catadioptric element 23 of this light path of present embodiment comprises the refrative mirror 23 that is arranged at respectively between prism 22 and the lens 241, and the refrative mirror 23 between lens 241 and the image sensing device 25.Because reflecting surface 221 is curved surfaces, this moment, reflecting surface 221 was asymmetric with respect to the Observing axis 240 of photodetector 24, referring to the curve that is intersected by this reflecting surface 221 and Observing axis 240 place surface levels and the tangent line that this Observing axis 240 joinings determine, with these Observing axis 240 out of plumb, is the monoclinic phase friendship.Those skilled in the art are to be understood that, because this photodetector 24 had used the catadioptric element 23 of light path before lens 241, thereby the Observing axis 240 of photodetector 24 should be the corresponding adjustment of catadioptric optical path direction of the catadioptric element 23 of optical axis 245 respective optical path of these lens 241.Light by exit facet 222 outgoing of prism 22 is projected to refrative mirror 23, light path changes and is incident to lens 241, and lens 241 again change light path to another refrative mirror 23 by these refrative mirror 23 reflections with a then outgoing of view angle focused ray and are projected to visual detector 25.Launch in 22 1 jiaos on prism because asymmetrical light channel structure, reflecting surface 221 are concentrated light, and photodetector 24 adopts catadioptric light path design effectively to utilize vacant space, the more effective size that reduces product.
Fig. 7 is the work of the overlooking synoptic diagram of fingerprint acquisition device 20 according to still another embodiment of the invention.As shown in Figure 7, this finger print detection device 30 comprises a light source 31, a prism 32, a photodetector 34, and an imageing sensor 35.The exit facet 322 of this prism 32 also can be curved surface, thereby the light of reflecting surface 321 reflections is had certain focussing force; Be conducive to improve subsequent optical path, such as the image quality of the lens 341 of photodetector 34.
Above-described embodiment is preferred embodiments more of the present invention, and those skilled in the art should know a lot of alternate embodiment in the practical application.As gather the applied image-forming principle of fingerprint and be not limited to aforesaid way, can be that the fingerprint ridge imaging is deceived, fingerprint paddy and background are bright; Reflecting surface can have a plurality of, and the mode of reflection has mirror-reflection or total reflection; The camera lens of photodetector can have multiple lens etc.Those skilled in the art are to be understood that reflecting surface among the present invention and exit facet all are reflecting surface and the exit facets that the light for reflection or outgoing is detected in view angle by photodetector.And those skilled in the art are to be understood that when light is projected to exit facet through the reflection of a plurality of reflectings surface, and this moment, the Observing axis of photodetector was that reflecting surface (the intersection tangent plane when plane or the curved surface) out of plumb that is projected to exit facet with light the most at last.
Fingerprint acquisition device of the present invention adopts the asymmetrical beam line structure, so that the light of reflecting surface reflection can concentrate on one jiao of ejaculation of prism, need not unnecessary symmetric space setting, shorten product sizes; Especially when adopting catadioptric light path design, this advantage is more outstanding.Simultaneously owing to need not symmetrical light path design, flexible design and more be conducive to be applied to various occasions as required is such as mobile phone, computing machine etc.
Technology contents of the present invention and technical characterstic disclose as above, yet those of ordinary skill in the art still may be based on teaching of the present invention and announcements and done all replacement and modifications that does not deviate from spirit of the present invention.Therefore, protection scope of the present invention should be not limited to the content that embodiment discloses, and should comprise various do not deviate from replacement of the present invention and modifications, and is contained by the present patent application claim.
Claims (7)
1. a fingerprint acquisition device comprises light source, prism, photodetector, and imageing sensor; Described prism has the fingerprint collecting face, at least one reflecting surface, and exit facet; The light that described light source sends is injected this prism, and this photodetector detects the light that this exit facet penetrates in its view angle scope, and it is transmitted to this imageing sensor; The reflecting surface that wherein light is reflexed to this exit facet is asymmetric with respect to the Observing axis of this photodetector, and when this reflecting surface was the plane, straight line and this Observing axis monoclinic phase that itself and this Observing axis place surface level intersects were handed over; When this reflecting surface is curved surface, tangent line and the friendship of this Observing axis monoclinic phase that the curve that is intersected by this curved surface and this Observing axis place surface level and this Observing axis joining determine.
2. fingerprint acquisition device according to claim 1, wherein this at least one reflecting surface and exit facet are plane or curved surface.
3. described fingerprint acquisition device one of according to claim 1-2, wherein this at least one reflecting surface is mirror-reflection or total reflection mode.
4. described fingerprint acquisition device one of according to claim 1-2, wherein this photodetector comprises camera lens, and this camera lens comprises at least one lens.
5. fingerprint acquisition device according to claim 4, wherein this photodetector further comprises at least one catadioptric light path element, and this at least one catadioptric light path element is refrative mirror or right-angle prism.
6. fingerprint acquisition device according to claim 5, wherein this at least one catadioptric light path element is located between the exit facet and this at least one lens of this prism.
7. fingerprint acquisition device according to claim 5, wherein this at least one catadioptric light path element is located between these lens and this imageing sensor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200910171644 CN102004912B (en) | 2009-09-01 | 2009-09-01 | Fingerprint acquisition device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200910171644 CN102004912B (en) | 2009-09-01 | 2009-09-01 | Fingerprint acquisition device |
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| Publication Number | Publication Date |
|---|---|
| CN102004912A CN102004912A (en) | 2011-04-06 |
| CN102004912B true CN102004912B (en) | 2013-10-30 |
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| CN 200910171644 Active CN102004912B (en) | 2009-09-01 | 2009-09-01 | Fingerprint acquisition device |
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Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104766050B (en) * | 2015-03-19 | 2018-01-12 | 深圳百迈技术有限公司 | Fingers and palms line imaging system |
| CN107437055A (en) * | 2016-05-25 | 2017-12-05 | 深圳印象认知技术有限公司 | A kind of image acquisition device and fingerprint collecting equipment |
| CN107526998A (en) * | 2016-06-21 | 2017-12-29 | 安帝司股份有限公司 | Optical fingerprint sensor and its prism module |
| WO2018095115A1 (en) * | 2016-11-23 | 2018-05-31 | 广东欧珀移动通信有限公司 | Assembly with housing of terminal, and terminal |
| CN108009500A (en) * | 2017-11-30 | 2018-05-08 | 北京集创北方科技股份有限公司 | Finger print detection device and its detection method, touch-screen and electronic equipment |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1555542A (en) * | 2001-09-17 | 2004-12-15 | ������������ʽ���� | Optical fingerprint acquisition apparatus |
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Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1555542A (en) * | 2001-09-17 | 2004-12-15 | ������������ʽ���� | Optical fingerprint acquisition apparatus |
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