Multi-touch sensing through frustrated total internal reflection
First Claim
1. A multi-touch sensing system, comprising:
- an optical waveguide having first and second sides;
a compliant layer directly coupled to the first side of the optical waveguide, the compliant layer and the optical waveguide having substantially similar indexes of refraction so that light of at least one wavelength received by the optical waveguide in a predetermined direction undergoes total internal reflection within the optical waveguide and the compliant layer;
a cladding layer directly coupled to the compliant layer and having an index of refraction sufficiently lower than the index of refraction of the compliant layer so that deformation of the cladding layer causes some of the light undergoing total internal reflection to scatter and to escape the compliant layer and the optical waveguide; and
an image sensor adapted to detect at least some of the light that escapes the compliant layer and the optical waveguide.
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Abstract
High-resolution, scalable multi-touch sensing display systems and processes based on frustrated total internal reflection employ an optical waveguide that receives light, such as infrared light, that undergoes total internal reflection and an imaging sensor that detects light that escapes the optical waveguide caused by frustration of the total internal reflection due to contact by a user. The optical waveguide when fitted with a compliant surface overlay provides superior sensing performance, as well as other benefits and features. The systems and processes described provide true multi-touch (multi-input) and high-spatial and temporal resolution capability due to the continuous imaging of the frustrated total internal reflection that escapes the entire optical waveguide. Among other features and benefits, the systems and processes are scalable to large installations.
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Citations
20 Claims
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1. A multi-touch sensing system, comprising:
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an optical waveguide having first and second sides; a compliant layer directly coupled to the first side of the optical waveguide, the compliant layer and the optical waveguide having substantially similar indexes of refraction so that light of at least one wavelength received by the optical waveguide in a predetermined direction undergoes total internal reflection within the optical waveguide and the compliant layer; a cladding layer directly coupled to the compliant layer and having an index of refraction sufficiently lower than the index of refraction of the compliant layer so that deformation of the cladding layer causes some of the light undergoing total internal reflection to scatter and to escape the compliant layer and the optical waveguide; and an image sensor adapted to detect at least some of the light that escapes the compliant layer and the optical waveguide. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A multi-touch sensing system, comprising:
a compliant optical waveguide having an index of refraction sufficient to cause light of at least one wavelength received in a predetermined direction to undergo total internal reflection within the compliant optical waveguide, the compliant optical waveguide having first and second sides; a cladding layer directly coupled to the first side of the compliant optical waveguide and having an index of refraction sufficiently lower than the index of refraction of the compliant optical waveguide so that deformation of the cladding layer causes some of the light undergoing total internal reflection to scatter and to escape the compliant optical waveguide; and an image sensor adapted to detect at least some of the light that escapes the compliant optical waveguide. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
Specification