TW571249B - Optical system of fingerprint image capture apparatus - Google Patents

Abstract

An optical system of fingerprint image capture apparatus comprises an optical platen substantially in a flat shape, a source light, and an image sensor. The optical platen includes a generally planar contact face having a dull rough surface against which a finger is placed, and a generally planar viewing face at the side of which is placed the image sensor and the light source. An incident light from the light source that strikes a region of the contact surface touched by a fingerprint ridge is scattered and passes through the viewing face to be substantially captured by the image sensor. An incident light that strikes a region of the contact face corresponding to a fingerprint valley is scattered and further passes out of the optical prism by refraction. The fingerprint ridge thereby appears as brighter regions and the fingerprint valley as darker regions.

Description

571249 V Description of the invention Q) The present invention relates to an optical c device of an image capture device § ^ pattern image capture device ′ more particularly-a fingerprint recognition system usually requires the use of fingerprint images. Of course, two ===; devices to obtain the same image at the output of the image capture device: two: "Use-a triangular optical prism to ensure that the capture device is provided on the device. Whether your finger is placed in the image capture

ΐ1Used :: Draw the optical system and its application mechanism used to capture fingerprint images. As shown in the figure, the conventional optical system includes a triangular transparent optical prism 10, a light source 13, and an image sensor 5]. The optical frame 10 includes a contact surface 10a above which a finger is placed, a light receiving surface 10b 'that receives light from the light source 13 and an observation surface 丨 c, so that the light reflected by the fingerprint is reflected. The image light leaves 稜鏡 10 and is captured by the image sensor 15. 1 0 a ′ 1 0 b and 1 0 C are both flat surfaces and are smooth to form an appropriate optical channel as described below.

As shown in the enlarged view in FIG. 1B, the incident light ray L1 is scattered and / or absorbed through 稜鏡 丨 〇 and irradiated to the fingerprint ridge 22 of an area of the contact surface 10a to generate a scattered light SL1. In contrast, when the incident light ray L2 is irradiated onto an area corresponding to the fingerprint valley 24 on the contact surface 10a, the incident light ray L2 is totally reflected under the condition that the incident angle is greater than the critical reflection angle. The reflected light ray RL2 leaves 稜鏡 10 through the observation surface 10c, and is then captured by the image sensor 15. Since the incident light ray L2 that hits the area corresponding to the fingerprint valley 24 is totally reflected,

L) _wi.ptd Page 5 571249 V. Description of the invention (2) The incident light L1 that illuminates the area corresponding to the fingerprint ridge 22 is scattered and / or constricted. Therefore, in the image formed by the image sensor 15, The fingerprint valley 24 appears brighter than the king, while the fingerprint ridge 22 appears darker. The above-mentioned conventional optical system has a disadvantage, that is, the image may not be fully formed on the image sensor, and the formed image is negatively reduced. Also, the triangular shape of the optical frame limits the possible devices of the optical system in the image sensor /. This particularly causes a disadvantage when the need of the image sensor is reduced. " One feature of the present invention is to provide a fingerprint image capture device with light and j, which has a reduced size, so that the image capture device can be installed; another sophomore of the present invention is to provide a fingerprint image capture device Allows formation of larger fingerprint images. You Ziyu, still another feature of the present invention is to provide an optical system with fingerprints to achieve the shadow of the elastic structure = 仏 capture device can be used-a typical video recorder to extract fingerprints = = = = above and Other ", this hair: "Texture. The optical system of the device 'includes-a substantially flat flower, a pattern image capture source, and an image sensor. The light wind ^ = pre-pressing plate, a light contact surface Above, it is provided with the angle of the finger, a rough surface is placed on one end of the image sensor. Said ^ and an observation surface, which learns the pressure plate and irradiates the contact surface .: into ~ light = emit a light through this light It is scattered. Irradiated to the opposite shore ;: the contact surface and the uneven surface of the fingerprint ridge 'the incident area of the contact surface of the valley valley 9190t \ v ('. Ptd 571249 V. Description of the invention (3) — "- -The line is scattered and then diffracted to leave the optical beam. It undergoes the diffraction and scattering between the fingerprint valley and the contact surface. The area of the contact surface corresponding to the ridge of the fingerprint is the light emitted by the observation surface. Leaving the optical platen and being sensed by the image It should be capture =. The light scattered by the area corresponding to the fingerprint valley of the contact surface can basically not be obtained by the image response sensor. The density of the image light from the fingerprint valley is lower than the light scattered from the area of the fingerprint ridge. In the image sensor, the fingerprint valley is displayed in a dark area, and the fingerprint ridge is displayed in a bright area. Thus, the fingerprint image really has a larger size. The optical system of the fingerprint image capturing device is an electronic system. Middle, = make, the optical pressure plate installed in the image capture window of the electronic component can be% #With this movable device, the optical pressure plate can cover or expose the stand At the time of image capture window, the optical system is in the state of grain capture. To capture ==: window, the optical system is "overviewed" and the following detailed description is within the scope of the present invention. For a detailed explanation of the present invention. ', 淮 Huai = :! is the-part of this specification' which provides a further explanation of the present invention, these drawings combined with the description will show examples of implementation of the present invention ' Explain the principles of the present invention, wherein: FIG formula of Numerals: 10: 1 0 a optical Prism: contact surface 10B: Light receiving surface

㈣) twr.ptd 571249 V. Description of the invention (4) 10c: Viewing surface 13: Light source 15: Image sensor 2 0: Finger 2 2: Fingerprint ridge 2 4: Fingerprint valley 1 0 0: Optical platen 100a: Optical platen Surface 100b: Optical platen surface 1 2 0: Light source 1 50: Image sensor 2 0 • Fingerprint ridge 204: Fingerprint valley 3 0 0: Mobile phone 320: Image capture window embodiment The reference drawings are only exemplary descriptions of the present invention and are not intended to limit the present invention. The drawings only show the approximate shapes of the structures, and are not drawn according to the proportions of the entities. They only include elements related to the present invention. Other elements not related to the present invention are omitted. In the drawings and the following description, the same elements or parts are denoted by the same reference numerals or symbols. Referring to FIG. 2A and FIG. 2B, a fingerprint image capturing device according to an embodiment of the present invention is shown. FIG. 2A is a schematic diagram showing a device according to the present invention.

9190twf.ptd Page 8 571249 V. Description of the invention (5) The optical system of the fingerprint capture device, and Figure 2B is an enlarged view of part 2A. As shown in FIG. 2A, the optical system 00 includes an optical platen 100, a light source 120, and an image sensor 150. A lens group (not shown) can also be installed between the image sensor 15 and the optical platen 100. The light source 120 preferably includes light emitting diodes (LEDs) arranged in a single row, but a light source that provides incident light of the optical platen 00 in other forms can also be used. The image sensor 150 captures the image light from the optical platen 丨 〇 〇 and converts it into electrical signals. The image sensor 50 includes a charge coupled device (CCD), a mutual capture metal oxide semiconductor (CM0s) element, or a contact image sensor (C IS). The optical platen 100 is formed of transparent glass, plastic, or other appropriate translucent materials. It preferably has a substantially flat shape. For example, it is a solid of 'an approximately parallelepiped' shown in the figure and having two parallel planes of 1003 and 0b. Although the faces 100a and 10a shown in FIG. 2A are flat with each other, they can also be slightly tilted to obtain different incident and outgoing rays.

2 position. The surface 1GGa is formed by a-generally flat surface, such as 2B :::: It is preferably characterized by matte grains. The appropriate surface difference is formed by each 9: method, such as appropriate grinding. A finger 2 0 0 can be placed on the negotiable face to capture the image of the fingers 彡 ^ ^ ^ ^ ^, 、, 文, shirt image capture. The surface 100b is formed by a large flat surface, which is basically a wild goose ^ Ma Qian It includes a viewing surface placed at the 150-end of the image-sensing state. In the embodiment of Figure _ ^ ^ A ^ ^ you, the light source can be placed in the field at the same end of the image sensor 150. A finger image is formed on the image sensor 1 50, and the finger 2 0 0 is placed on

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571249 V. Description of the invention (6) The contact surface 100a of the optical platen 100 makes the fingerprint contact the uneven surface. As shown in FIG. 2B, the incident light rays (LI ', L2') emitted by the light source 120 enter the optical platen 100 and irradiate the contact surface 120a. Any suitable incident light can be used in the present invention, and a discordant incident light is used here. In the area in contact with the fingerprint ridge on the contact surface 100a, the incident light ray L1 'is scattered to multiple directions due to the uneven surfaces of the contact surface 100a and the fingerprint ridge 202, and the scattered light SL1 is generated. Part of the scattered light SL1 'is emitted from the pressure plate 100 through the observation surface 100b and captured by the image sensor 150. In one of the areas corresponding to the fingerprint valley 204, part of the light L2 is scattered due to the unevenness of the contact surface 100a, while the other part of the light L2 is diffracted and passes through and leaves the platen 100. Part of the diffracted light is scattered / absorbed by the surface of the fingerprint valley 204, and the scattered part is guided to the uneven surface of the contact surface 100a, and then scattered and diffracted through the contact surface 100a. After the above multiple scattering and diffraction in the area of the fingerprint valley 204, the intensity of the light from the fingerprint valley 204 is substantially smaller than the intensity of the light from the fingerprint ridge. As a result, in the fingerprint image, the fingerprint valley 204 shows a dark area, and the fingerprint ridge 202 shows a bright area. With the above optical system, a larger image can be known. In order to obtain a better contrast between the ridge 200 and the valley 204, the fingerprint image can be processed by a special image. Referring to FIG. 3, which shows a perspective view of the optical system of the present invention. As shown in the figure, a fingerprint image capturing device including the above optical system can be used in a mobile phone 300, which includes an image capturing window 320 to learn the board. 100 pivotable ground device, and weep in the split image

9190twf.ptd 571249 V. Description of the invention (7) Place the contact surface 100a to rotate outwards, and to capture the image of the fingerprint, the pressure plate 100a rotates the Hanchashun surface H0b inward. 320, and the finger is placed on the contact surface 100a. Repeat the image capture window to install a mobile phone in a mobile phone 3 0… 4 Use the fingerprint recognition switch to switch the mobile phone 2 to use the pressure plate 1 0 〇 to expose the fingerprint 3 J image capture device can be designed as a typical Video 'as of 3:20: pattern; v :: pass: video recorder ... the user ㈣ Because the contact surface with the fingerprint usually has a fingerprint image of ==, and the conventional optical prism == Ming: On the original A flat optical platen reduces the size of the optical system. Social media, = The size of the device can be reduced. Furthermore, ③ the second light: structure m :; [the optical system of the present invention allows-fingerprint capture of various c can be obtained by modifying various parts of the above structure, , He,, and σ, without departing from the scope and spirit of the present invention. For example, the upper-level private image capture device is implemented by a mobile phone. However, the capture of fingerprints can be realized in other ways, and the above advantages can be obtained. Because you / have Γι ί ^ Example is only used as a narrative example of manufacturing and implementing the present invention, the modifications of the spirit of the invention defined in the patent scope of the two patents are all in the present invention

9190twf.pui Page 11 571249 Brief description of the drawings Figure 1 A shows the optical system of a conventional fingerprint image capture device; Figure 1 B shows the mechanism of an optical system of a traditional fingerprint image capture device; Figure 2 A shows FIG. 2B illustrates an optical system of a fingerprint image capture device according to the present invention; FIG. 2B illustrates an optical system and a general mechanism of the fingerprint image capture device according to the embodiment of the present invention; and FIG. According to the embodiment of the present invention, the optical system and application of the fingerprint image capturing device are applied. m

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Claims (1)

571249 VI. Patent Application Fanyuan School Department 1 system of 'type optical pressure plate' is used for a fingerprint image capture device-light / ,,, and the optical pressure plate includes a contact surface, A mention | &observe; for = one ：：： 得 ： Fingerprints of the fingers, and-the more transparent, the other is a flat surface, so that the light of a fingerprint image can be learned. : J ΐ] f A scattering of incident light exits the light ~ captures like a sensor. And waste L > The optical platen as described in the scope of U.S. patent application, item 1, wherein the photon 3 material includes transparent glass or plastic. The touch surface includes the optical pressure plate as described in item 1 of the scope of the patent application, wherein the ridges and the ridges are connected with appropriate thicknesses to allow the light rays scattered on the area contacting a fingerprint # 纹 = one of the touch surfaces, And the light is scattered and diffracted corresponding to one of the areas of a contact surface, and the fingerprint ridges & p ^ β ^ Liu Guang, 彳 $ in a formed fingerprint are shown in a shell area, and The fingerprint valley is displayed in a dark area. The optical platen described in item 1 of the scope of application for patents, wherein the contact surface and the viewfinder 5 w surface are substantially flat. The optical platen described in Item 1 of the patent application scope has a shape of 6 Λ.句 杯 _! Once refers to the optical system of the mosquito image, the optical system can be mounted on an electronic component of an optical image capture window, the optical system includes: for the reverse, including a contact surface, which has a Glossy and rough surface, on the next day, to capture a fingerprint image, and an opposite viewing surface, Gan- / _ secret cut & you-smooth surface, where the optical pressure plate is installed in the The image was captured from _ and eclipsed 4 ^ _, then the distant contact surface turned outward and the observation surface turned inward 571249 A light source 'is placed near the observation surface and emits an incident light into the optical platen' and irradiates the interface; and an image sensor is placed near the observation surface to receive the incident light via One of the light scattered by the contact surface of the finger emits image light. 7. The optical system according to item 6 of the scope of patent application, wherein the material of the optical platen is transparent glass or plastic. 8 · The optical system as described in item 6 of the patent claim, wherein the contact surface includes an appropriate roughness to allow light to be irradiated onto a contact area, a light scattering area, and light, respectively. The light corresponding to a region of the fingerprint surface corresponding to a fingerprint is scattered and diffracted. In a formed fingerprint image, the fingerprint ridge is displayed as a bright area and the finger is displayed as a dark area. 6 a 9. According to the optical system described in item 6 of the scope of patent application, the contact surface and the observation surface are substantially flat. /. The optical system described in item 6 of the patent application range, wherein the doro roof has a substantially flat shape. The optical system described in item 6 of the scope of patent application: Light: Press J is a movable device installed in the image capture window and the exposed image capture window, so the optical system can be used in the Image insertion and fingerprint image capture ... On the day of uncovering the road $ β is again a video camera optical system. Catch window is applied for the optical system described in item 6 of the patent scope, and the light source includes a light diode. Where the 9190twf.ptd Page 14 571249 VI. Patent application scope 13. The optical system described in item 6 of the patent application scope, wherein the image sensor includes a charge coupled device, a complementary metal-oxide semiconductor device, or a contact image sensor Device. 14. The optical system as described in item 6 of the scope of patent application, wherein when the optical system is installed in a mobile phone as an internal image capturing device, it can be set to obtain a fingerprint image a farther away Environmental Image 0 m 9190twf.ptd Page 15