Method of measuring the movement of an input device
First Claim
1. A method of measuring the movement of an input device and an object relative to each other along at least one measuring axis, the method comprising the steps of:
- illuminating an object surface with a measuring laser beam for each measuring axis, and converting a selected portion of the measuring beam radiation reflected by the surface into an electric signal, which is representative of the movement along said measuring axis, characterized in that measuring beam radiation reflected back along the measuring beam and re-entering the laser cavity, which emits the measuring beam, is selected and in that changes in operation of the laser cavity, which are due to interference of the re-entering radiation and the optical wave in the laser cavity and are representative of the movement, are measured.
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Accused Products
Abstract
An optical input device for an apparatus, generating input signals by moving the device and an object (15) relative to each other and measuring the movement by means of the effects of self-mixing in a diode laser (3,5) and Doppler shift caused by the movement. For each measuring axis (X,Y,Z) radiation from a diode laser (3,5) is converged on a window (12) across which the object (15) moves Part of the radiation scattered by the object, whose frequency is Doppler-shifted due to the movement, re-enters the laser cavity (20) and causes a change in cavity properties. By measuring such a change, for example by means of a photo diode, information about the movement is obtained. As the input device is small and cheap, it can be used in a number of different consumer apparatus.
53 Citations
33 Claims
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1. A method of measuring the movement of an input device and an object relative to each other along at least one measuring axis, the method comprising the steps of:
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illuminating an object surface with a measuring laser beam for each measuring axis, and converting a selected portion of the measuring beam radiation reflected by the surface into an electric signal, which is representative of the movement along said measuring axis, characterized in that measuring beam radiation reflected back along the measuring beam and re-entering the laser cavity, which emits the measuring beam, is selected and in that changes in operation of the laser cavity, which are due to interference of the re-entering radiation and the optical wave in the laser cavity and are representative of the movement, are measured. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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Specification