公开(公告)号：EP0345368A1

公开(公告)日：1989-12-13

申请号：EP88109114.4

申请日：1988-06-08

Applicant: FINGERMATRIX INC.

Inventor： Schiller, Michael ,  Marcus, Daniel H.

IPC: A61B5/10

CPC classification number: G06K9/00013 ,  A61B5/1172

Abstract: A curved cylindrical segment platen (18) has a concave touching surface (18b). An interrogating slit light beam is scanned around the platen to scan a finger held against the touching surface. An optical imaging system images (20) the zone illuminated onto an array of photo-transducers (22) to provide a signal representing the fingerprint. The optical system is rotated (40) around the platen. The axis (17) of the interrogating light beam (16) is substantially normal to the touching surface (18b). The axis (28a) of the imaging system is off normal by about 56 degrees, an amount which is greater than a critical angle equal to the maximum angle of refraction (MAR) in the platen. This critical angle is approximately 41 degrees. The axis (28) of the imaging system is also off normal to the non-touching surface (18a) by an angle that is less than this critical angle of 4l degrees and thus less than the angle of total internal reflection (TIR). As a consequence, the image at the photo-transducers provides a completely dark valley zone and a sharply contrasting light image ridge ,zone.

Abstract translation: 弯曲的圆柱形段压板（18）具有凹形接触表面（18b）。 围绕压板扫描询问狭缝光束，以扫描保持在触摸表面上的手指。 光学成像系统将照射到光变换器阵列（22）上的区域图像（20），以提供表示指纹的信号。 光学系统围绕压板旋转（40）。 询问光束（16）的轴线（17）基本上垂直于接触表面（18b）。 成像系统的轴线（28a）正常离开约56度，其量大于等于压板中的最大折射角（MAR）的临界角。 该临界角约为41度。 成像系统的轴线（28）也与非接触表面（18a）垂直的角度小于该临界角度为41度并因此小于全内反射角度（TIR）。 因此，光电转换器上的图像提供了一个完全黑暗的谷地区域和一个明显对比的光图像脊，区域。

公开(公告)号：EP0280041A1

公开(公告)日：1988-08-31

申请号：EP88100979.9

申请日：1988-01-23

Applicant: Fingermatrix, Inc.

Inventor： Schiller, Michael ,  Marcus, Daniel H.

IPC: A61B5/10

CPC classification number: G06K9/00033 ,  A61B5/1172 ,  G06K9/00026 ,  G07C9/00158

Abstract: The technique for optically scanning a finger to produce a fingerprint image involves positioning the finger surface to be optically scanned so that it is exposed and, in particular, is not pressed against a platen. A slit light beam along the length of the forward part of the finger is circumferentially rotated (38) about an axis (x-x) about the nominal center of the finger. A reflected slit light beam carries modulation information which is focused on a linear array of photo-electric transducers (12) to provide the fingerprint image. The interrogating light is coherent, substantially collimated, light. The plane of the interrogating slit light beam and the plane of the reflected modulated slit light beam are coplanar thereby establishing an illumination plane (42). The illumination plane is parallel to the axis of the finger and is rotated about that axis during the interrogating scan. The illumination plane is slightly offset (d) from that rotational axis and the incident light (16) in the illumination plane impinges on the finger surface at a slight off-normal axis. This offset and off-normal incidence creates two dimensional shadowing. The finger surface being interrogated is positioned slightly off of the object plane for the downstream focusing optics thereby creating a constructive destructive interference effect at the image plane defined by the transducers.

Abstract translation: 用于光学扫描手指以产生指纹图像的技术涉及定位要被光学扫描的手指表面，使得其被暴露，并且特别地不压在压板上。 沿着手指前部的长度的狭缝光束围绕手指的标称中心的轴线（x-x）周向旋转（38）。 反射的狭缝光束承载聚焦在光电换能器（12）的线性阵列上以提供指纹图像的调制信息。 询问光是相干的，基本准直的，光的。 询问狭缝光束的平面和反射调制的狭缝光束的平面是共面的，由此建立照明平面（42）。 照明平面平行于手指的轴线并且在询问扫描期间围绕该轴线旋转。 照明平面与该旋转轴稍微偏移（d），并且照明平面中的入射光（16）在稍微偏离法线的轴线上撞击在手指表面上。 这种偏移和非正常入射产生二维阴影。 被询问的手指表面被定位成稍微离开对象平面以用于下游聚焦光学器件，从而在由换能器限定的图像平面处产生结构性的破坏性干涉效应。