Finger touch sensors and virtual switch panels

• US 6,236,037 B1
• Filed: 02/19/1999
• Issued: 05/22/2001
• Est. Priority Date: 02/20/1998
• Status: Expired due to Fees

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Mascaro, Stephen, Chang, Kuo-Wei, Asada, Haruhiko H.
• Primary Examiner(s): EVANS, FANNIE L
• Application Number:
  US09/253,437
• Time in Patent Office: 823 Days
• Field of Search: 250/221, 250/231.19
• US Class Current: 250/221
• CPC Class Codes: G01L 1/248 using infrared G01L1/241, G01L1/242 take precedence
• CPC Class Codes: G01L 5/22 for measuring the force applied to control members, e.g. control members of vehicles, triggers
• CPC Class Codes: G01L 5/226 to manipulators, e.g. the force due to gripping
• CPC Class Codes: G06F 2203/0331 Finger worn pointing device
• CPC Class Codes: G06F 3/011 Arrangements for interaction with the human body, e.g. for user immersion in virtual reality blind teaching G09B21/00
• CPC Class Codes: G06F 3/033 Pointing devices displaced or positioned by the user , e.g. mice, trackballs, pens or joysticks; Accessories therefor digitisers characterised by the transducing means G06F3/041

Abstract

A device for detecting contact pressure applied to a finger, the finger having a fingernail illuminated by light, comprises at least one photodetector for measuring a change in light reflected by an area of the finger beneath the fingernail in response to the contact pressure applied to the finger. The photodetector provides a signal corresponding to the change in light reflected. The device also includes a processor for receiving the signal and determining whether the change corresponds to a specified condition. The photodetector may be enclosed in a housing and coupled to the fingernail.

Claims

1. A device for detecting contact pressure applied to a finger, the finger having a fingernail illuminated by light, the device comprising:

at least one photodetector for measuring a change in light reflected by an area of the finger beneath the fingernail in response to the contact pressure applied to the finger and providing a signal corresponding to the change; and

a processor for receiving the signal and determining whether the change corresponds to a specified condition.

2. A device according to claim 1, wherein the photodetector is an array of photodetectors, the array of photodetectors having a spectral range.

3. A device according to claim 2, wherein the spectral range includes visible and infrared wavelengths.

4. A device according to claim 1, further including at least one light source, coupled to the photodetector, the light source for emitting light into the fingernail.

5. A device according to claim 1, further including a set of light sources coupled to the photodetector, the set of light sources having varying wavelengths and for emitting light into the fingernail.

6. A device according to claim 1, further including:

a housing, enclosing the photodetector; and

a coupling element, connected to the housing, the coupling element for coupling the housing to the fingernail.

7. A device according to claim 6, wherein the coupling element is a transparent adhesive material.

8. A device according to claim 1, further including:

a surface for providing contact pressure to the finger, the surface having indicia; and

a position locator, in signal communication with the processor and coupled to the finger, the position locator for identifying the position of the finger with respect to the surface.

9. A method for detecting contact pressure applied to a finger, the finger having a fingernail illuminated by light, the method comprising:

providing at least one photodetector;

measuring a change in light reflected by an area of the finger beneath the fingernail in response to the contact pressure applied to the finger;

providing a signal corresponding to the change; and

comparing the change to a specified condition.

10. A method according to claim 9, further including illuminating the fingernail with light from a light source.

11. A method according to claim 10, further including:

enclosing the photodetector and the light source in a housing; and

coupling the housing to the fingernail.