Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
249 words
A fingerprint sensor for producing an electrical signal corresponding to the papillary pattern in the skin of a finger (2), comprising a prism (12) of transparent material on one of whose sides is arranged an elastic contact surface (18) for impression by the finger, in which contact surface the respectively impressed papillary pattern produces a corresponding topographic relief by elastic deformation, which relief is illuminated by a light beam (13) transversely supplied to the contact surface (18) through the transparent prism (12) from a light source (4), the illuminated relief reflecting a light beam (9) transversely to the contact surface (18), which beam is modulated to correspond to said relief, which beam is supplied to a light-sensitive field (22) of an optoelectric photo detector device (26) for detecting the distribution of the light intensity incident on the field (22) and which produces an electrical signal (a) which corresponds to the topographic relief and simultaneously corresponds to the impressed papillary pattern, characterised in that on one side of the non-elastic prism (12) there is applied a sensor plate (16) of transparent elastic material whose exposed top side forms the contact surface (18), that a light diffusor (6, 7) is arranged in the light beam (13) from the light source (4) preceding the contact surface (18), and that in the light beam (19) reflected from the illuminated relief, preceding the light-sensitive field, there is arranged a focussing optical system (20) which focusses the illuminated relief (18) onto the light-sensitive field (22).
Claim 2
Dependent Claim
249 words
A fingerprint sensor for producing an electrical signal corresponding to the papillary pattern in the skin of a finger (2), comprising a prism (12) of transparent material on one of whose sides is arranged an elastic contact surface (18) for impression by the finger, in which contact surface the respectively impressed papillary pattern produces a corresponding topographic relief by elastic deformation, which relief is illuminated by a light beam (13) transversely supplied to the contact surface (18) through the transparent prism (12) from a light source (4), the illuminated relief reflecting a light beam (9) transversely to the contact surface (18), which beam is modulated to correspond to said relief, which beam is supplied to a light-sensitive field (22) of an optoelectric photo detector device (26) for detecting the distribution of the light intensity incident on the field (22) and which produces an electrical signal (a) which corresponds to the topographic relief and simultaneously corresponds to the impressed papillary pattern, characterised in that on one side of the non-elastic prism (12) there is applied a sensor plate (16) of transparent elastic material whose exposed top side forms the contact surface (18), that a light diffusor (6, 7) is arranged in the light beam (13) from the light source (4) preceding the contact surface (18), and that in the light beam (19) reflected from the illuminated relief, preceding the light-sensitive field, there is arranged a focussing optical system (20) which focusses the illuminated relief (18) onto the light-sensitive field (22).
Claim 3
Dependent Claim
16 words
A sensor as claimed in Claim 1, characterised in that the prism (12) consists of glass.
Claim 4
Dependent Claim
41 words
A sensor as claimed in Claim 1 or 2, characterised in that an optical matching medium (14) is connected both to the sensor plate (16) and to the prism (12), being arranged between the sensor plate (16) and the prism (12).
Claim 5
Dependent Claim
30 words
A sensor as claimed in one of the preceding Claims, characterised in that the light diffusor (6, 7) consists of a glass plate (6) which has a roughened surface (7).
Claim 6
Dependent Claim
46 words
A sensor as claimed in one of Claims 1 to 3, characterised in that the light diffusor consists of a rough lateral surface (7) of the prism (12), through which the light beam which illuminates the topographic relief on the contact surface (18) enters the prism.