Systems and methods for capturing images using a pressure sensitive membrane

• US 10,726,241 B2
• Filed: 04/05/2016
• Issued: 07/28/2020
• Est. Priority Date: 04/06/2015
• Status: Active Grant

• Current Assignee: Identification International, Inc.
• Original Assignee: Identification International, Inc.
• Inventors: Dickerson, Bryan D., Fenrich, Richard K., Robinson, Christopher R., Cowen, Jr., William B.
• Primary Examiner(s): Hung, Yubin
• Application Number:
  US15/091,532
• Publication Number:
  US 20160292491A1
• Time in Patent Office: 1,575 Days
• CPC Class Codes: G06F 2203/04106 Multi-sensing digitiser, i.e. digitiser using at least two different sensing technologies simultaneously or alternatively, e.g. for detecting pen and finger, for saving power or for improving position detection
• CPC Class Codes: G06F 2203/04107 Shielding in digitiser, i.e. guard or shielding arrangements, mostly for capacitive touchscreens, e.g. driven shields, driven grounds
• CPC Class Codes: G06F 2203/04109 FTIR in optical digitiser, i.e. touch detection by frustrating the total internal reflection within an optical waveguide due to changes of optical properties or deformation at the touch location
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/04144 using an array of force sensing means position sensing using the local deformation of sensor cells G06F3/0447
• CPC Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers
• CPC Class Codes: G06F 3/0425 using a single imaging device like a video camera for tracking the absolute position of a single or a plurality of objects with respect to an imaged reference surface, e.g. video camera imaging a display or a projection screen, a table or a wall surface, on which a computer generated image is displayed or projected tracking a projected light spot to determine a position on a display surface G06F3/0386
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: G06F 3/0447 Position sensing using the local deformation of sensor cells
• CPC Class Codes: G06V 40/1324 by using geometrical optics, e.g. using prisms G06V40/1312 takes precedence

Abstract

A total internal reflection based imaging system may include a light transmitting member having an imaging surface. A pressure sensitive membrane may be arranged on the imaging surface. The pressure sensitive membrane may include a top surface, a bottom surface, and an elastic deformable film forming at least a portion of the top surface. The imaging system may include a textured surface disposed between the pressure sensitive membrane and the imaging surface. An application of pressure on the top surface may deform the deformable film to reduce a distance between the deformable film and the imaging surface. A light source may be configured to emit a light towards the imaging surface such that reduced total internal reflection of the light occurs where the bottom surface of the pressure sensitive membrane contacts the imaging surface. A sensor may be configured to capture the light reflected from the imaging surface.

Claims

1. A pressure sensitive membrane including:

an elastic deformable film having a top surface and a bottom surface opposite the top surface, wherein the elastic deformable film has less than a 20 μ

m thickness; and

a textured portion that is formed such that in a default position, an air gap exists between the pressure sensitive membrane and an imaging surface on which the pressure sensitive membrane is arranged, and wherein responsive to a finger applying pressure on the top surface of the pressure sensitive membrane, the pressure sensitive membrane is collapsed into a collapsed position and the air gap is diminished,

wherein a pattern corresponding to friction ridges of the finger is formed by engagement between the pressure sensitive membrane in the collapsed position and the imaging surface responsive to the finger applying pressure on the top surface of the pressure sensitive membrane, and wherein responsive to light being reflected from the imaging surface, an image of the pattern is optically captured and the image corresponds to the friction ridges of the finger applying the pressure.

2. The pressure sensitive membrane of claim 1, wherein a refractive index of the elastic deformable film is identical or near identical to that of a light transmitting member including the imaging surface.

3. The pressure sensitive membrane of claim 1, wherein the elastic deformable film comprises a polymer film including one or more of parylene, urethane, polyester, fluorinated ethylene propylene (FEP), ethylene tetrafluoroethylene (ETFE), perfluoroalkoxy (PFA), Polyether ether ketone (PEEK), and/or Kapton.

4. The pressure sensitive membrane of claim 1, wherein the textured surface includes one or more raised standoffs, a sinusoidal wave, a rough textured surface, a microcellular foam, and/or a non-porous layer.

5. The pressure sensitive membrane of claim 1, wherein the textured surface includes a plurality of nanowires.

6. The pressure sensitive membrane of claim 1, wherein the textured surface is cast from a surface of a mold.

7. The pressure sensitive membrane of claim 1, wherein the top surface and/or the bottom surface include one or more coatings, and wherein the elastic deformable film, including the one or more coatings, has less than a 20 μ

m thickness.

8. The pressure sensitive membrane of claim 7, wherein the one or more coatings are conductive.

9. A total internal reflection based imaging system comprising:

a light transmitting member having an imaging surface;

a pressure sensitive membrane arranged on the imaging surface, the pressure sensitive membrane including an elastic deformable film and having a top surface and a bottom surface opposite the top surface, wherein at least a portion of the bottom surface is formed by a textured portion, and wherein the elastic deformable film has less than a 20 μ

m thickness, and

wherein the textured portion is formed such that in a default position, an air gap exists between the pressure sensitive membrane and the imaging surface on which the pressure sensitive membrane is arranged, and wherein responsive to a finger applying pressure on the top surface of the pressure sensitive membrane, the pressure sensitive membrane is collapsed into a collapsed position and the air gap is diminished, and wherein a pattern corresponding to friction ridges of the finger is formed by engagement between the pressure sensitive membrane in the collapsed position and the imaging surface responsive to the finger applying pressure on the top surface of the pressure sensitive membrane;

a light source configured to emit a light towards the imaging surface from a side of the imaging surface opposite the pressure sensitive membrane; and

an imaging sensor configured to capture light reflected from the imaging surface such that an image of the pattern formed by engagement between the pressure sensitive membrane in the collapsed position and the imaging surface responsive to the finger applying pressure on the top surface of the pressure sensitive membrane is optically captured such that the image corresponds to the friction ridges of the finger applying the pressure.

10. The total internal reflection based imaging system of claim 9, wherein the light transmitting member is a prism or optical waveguide.

11. The total internal reflection based imaging system of claim 9, wherein a refractive index of the elastic deformable film is identical or near identical to that of the light transmitting member.

12. The total internal reflection based imaging system of claim 9, wherein the elastic deformable film comprises a polymer film including one or more of parylene, urethane, polyester, fluorinated ethylene propylene (FEP), ethylene tetrafluoroethylene (ETFE), perfluoroalkoxy (PFA), Polyether ether ketone (PEEK), and/or Kapton.

13. The total internal reflection based imaging system of claim 9, wherein the textured surface includes one or more raised standoffs, a sinusoidal wave, a rough textured surface, a microcellular foam, and/or a non-porous layer.

14. The total internal reflection based imaging system of claim 9, wherein the textured surface includes a plurality of nanowires.

15. The total internal reflection based imaging system of claim 9, wherein the textured surface is cast from a surface of a mold.

16. The total internal reflection based imaging system of claim 9, wherein the top surface and/or the bottom surface include one or more coatings, and wherein the elastic deformable film, including the one or more coatings, has less than a 20 μ

m thickness.

17. The total internal reflection based imaging system of claim 16, wherein the one or more coatings are conductive.

18. A fluorescent or scattered light imaging system comprising:

a light transmitting member having an imaging surface;

a pressure sensitive membrane arranged on the imaging surface, the pressure sensitive membrane including an elastic deformable film and having a top surface and a bottom surface opposite the top surface, wherein at least a portion of the bottom surface is formed by a textured portion, and wherein the elastic deformable film has less than a 20 μ

m thickness, and

wherein the textured portion is formed such that in a default position, an air gap exists between the pressure sensitive membrane and the imaging surface on which the pressure sensitive membrane is arranged, wherein responsive to a finger applying pressure on the top surface of the pressure sensitive membrane, the pressure sensitive membrane is collapsed into a collapsed position and the air gap is diminished, and wherein a pattern corresponding to friction ridges of the finger is formed by engagement between the pressure sensitive membrane in the collapsed position and the imaging surface responsive to the finger applying pressure on the top surface of the pressure sensitive membrane;

a light source configured to emit light from a side of the imaging surface opposite the pressure sensitive membrane such that additional fluorescent or scattered light is propagated into the pressure sensitive membrane at any location on the imaging surface at which the bottom surface of the pressure sensitive membrane contacts the imaging surface due to pressure exerted by the finger on the top surface of the pressure sensitive membrane; and

an imaging sensor configured to capture the fluorescent or scattered light emission from the imaging surface such that an image of the pattern formed by engagement between the pressure sensitive membrane in the collapsed position and the imaging surface responsive to the finger applying pressure on the top surface of the pressure sensitive membrane is optically captured and the image corresponds to the friction ridges of the finger applying the pressure.

19. The fluorescent or scattered light imaging system of claim 18, wherein the light transmitting member is a prism or optical waveguide.

20. The fluorescent or scattered light imaging system of claim 18, wherein a refractive index of the elastic deformable film is identical or near identical to that of the light transmitting member.

21. The fluorescent or scattered light imaging system of claim 18, wherein the elastic deformable film comprises a polymer film including one or more of parylene, urethane, polyester, fluorinated ethylene propylene (FEP), ethylene tetrafluoroethylene (ETFE), perfluoroalkoxy (PFA), Polyether ether ketone (PEEK), and/or Kapton.

22. The fluorescent or scattered light imaging system of claim 18, wherein the textured surface includes one or more of raised standoffs, a sinusoidal wave, a rough textured surface, a microcellular foam, and/or a non-porous layer.

23. The fluorescent or scattered light imaging system of claim 18, wherein the textured surface includes a plurality of nanowires.

24. The fluorescent or scattered light imaging system of claim 18, wherein the textured surface is cast from a surface of a mold.

25. The fluorescent or scattered light imaging system comprising of claim 18, wherein the top surface and/or the bottom surface include one or more coatings, and wherein the elastic deformable film, including the one or more coatings, has less than a 20 μ

m thickness.

26. The fluorescent or scattered light imaging system comprising of claim 25, wherein the one or more coatings are conductive.