Light emitting stylus and user input device using same
First Claim
1. A light-sensitive user input device comprising:
- a co-planar array of light-sensitive devices disposed to sense light transmitted through an input surface of the input device, nearest adjacent light-sensitive devices having a center-to-center spacing of no more than a maximum distance;
a stylus configured to emit a light beam detectable by the devices, the light beam exhibiting a cross-sectional profile having a known shape characterized by a known intensity variance across the beam profile, wherein the light beam exhibits a size at the plane of the devices that is greater than the maximum distance when the stylus is contacting the input surface; and
electronics coupled to the light-sensitive devices and configured to determine the position of the light beam to within a spacing that is less than the maximum distance using the known intensity variance of the beam profile.
1 Assignment
0 Petitions
Accused Products
Abstract
The present invention provides a user input device that includes and array of light detectors and a light emitting stylus configured to emit a beam of light detectable by the light detectors. The light beam is wide enough at the plane of the detectors so that at least two detectors are illuminated for all positions of interest. This allows the light beam position to be interpolated to obtain positional resolution that is greater than would be expected simply due to the spacing between detectors. Interpolation can be further aided by using a light beam that has a known variance in cross-sectional intensity. The present invention also provides for determining the orientation of the stylus by comparing the detected shape of the light beam cross-section to the known shape of the light beam cross-section.
-
Citations
13 Claims
-
1. A light-sensitive user input device comprising:
-
a co-planar array of light-sensitive devices disposed to sense light transmitted through an input surface of the input device, nearest adjacent light-sensitive devices having a center-to-center spacing of no more than a maximum distance; a stylus configured to emit a light beam detectable by the devices, the light beam exhibiting a cross-sectional profile having a known shape characterized by a known intensity variance across the beam profile, wherein the light beam exhibits a size at the plane of the devices that is greater than the maximum distance when the stylus is contacting the input surface; and electronics coupled to the light-sensitive devices and configured to determine the position of the light beam to within a spacing that is less than the maximum distance using the known intensity variance of the beam profile. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
-
11. A method of determining the position of a light beam at an input surface, comprising:
-
providing a co-planar array of light-sensitive devices disposed to sense light transmitted through the input surface; emitting the light beam with a known shape characterized by a cross-sectional profile having a known intensity variance, the light beam having a spot size sufficient for the light beam to be detected by at least two of the light-sensitive devices when the light beam is directed through the input surface; detecting the light beam by at least two of the light-sensitive devices; and determining the position of the light beam to an accuracy that is less than the center-to-center distance between nearest adjacent light-sensitive devices by interpolating signals measured during the detecting step using the known intensity variance of the light beam. - View Dependent Claims (12, 13)
-
Specification