Multi-touch sensing display through frustrated total internal reflection
First Claim
1. A multi-touch sensing display, comprising:
- a light source;
a display element having a viewer side and a rear side;
an optical waveguide, the optical waveguide having a contact surface, a non-contact surface, and one or more edge surfaces, the non-contact surface facing and covering at least a portion of the viewer side of the display element, at least one of the one or more edge surfaces of the optical waveguide being adapted to receive light emitted by the light source, the optical waveguide being adapted to cause some of the received light to undergo total internal reflection within the optical waveguide;
a compliant surface overlay having a touch surface and a display-side surface, the display-side surface facing the contact surface of the optical waveguide and being spaced apart from the contact surface by a gap, the optical waveguide, the compliant surface overlay and the gap therebetween being configured to promote total internal reflection of light in the optical waveguide, the compliant surface overlay being disposed sufficiently close to the optical waveguide to enable depression of the compliant surface overlay by an external force against the touch surface of the compliant surface overlay to cause the display-side surface of the compliant surface overlay to contact the contact surface of the optical waveguide, the optical waveguide and the compliant surface overlay being adapted to cause the total internal reflection within the optical waveguide to be frustrated upon contact of the contact surface of the optical waveguide by the display-side surface of the compliant surface overlay, the optical waveguide adapted to allow some of the light undergoing total internal reflection to escape through its non-contact surface when the total internal reflection is frustrated; and
at least an imaging sensor positioned opposing the non-contact surface of the optical waveguide and adapted to detect light escaping the optical waveguide toward the display element,wherein the compliant surface overlay includes a component that rejects ambient light of the same wavelengths as the light source, a component that reduces friction at an interaction surface, and a component that reduces glare.
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Accused Products
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 may be fitted with a compliant surface overlay to greatly improve sensing performance, minimize the affect of contaminants on and damage to the contact surface, to generally extend system life and to provide other benefits. The systems and processes 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 and are well suited for use with rear-projection and other display devices.
149 Citations
42 Claims
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1. A multi-touch sensing display, comprising:
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a light source; a display element having a viewer side and a rear side; an optical waveguide, the optical waveguide having a contact surface, a non-contact surface, and one or more edge surfaces, the non-contact surface facing and covering at least a portion of the viewer side of the display element, at least one of the one or more edge surfaces of the optical waveguide being adapted to receive light emitted by the light source, the optical waveguide being adapted to cause some of the received light to undergo total internal reflection within the optical waveguide; a compliant surface overlay having a touch surface and a display-side surface, the display-side surface facing the contact surface of the optical waveguide and being spaced apart from the contact surface by a gap, the optical waveguide, the compliant surface overlay and the gap therebetween being configured to promote total internal reflection of light in the optical waveguide, the compliant surface overlay being disposed sufficiently close to the optical waveguide to enable depression of the compliant surface overlay by an external force against the touch surface of the compliant surface overlay to cause the display-side surface of the compliant surface overlay to contact the contact surface of the optical waveguide, the optical waveguide and the compliant surface overlay being adapted to cause the total internal reflection within the optical waveguide to be frustrated upon contact of the contact surface of the optical waveguide by the display-side surface of the compliant surface overlay, the optical waveguide adapted to allow some of the light undergoing total internal reflection to escape through its non-contact surface when the total internal reflection is frustrated; and at least an imaging sensor positioned opposing the non-contact surface of the optical waveguide and adapted to detect light escaping the optical waveguide toward the display element, wherein the compliant surface overlay includes a component that rejects ambient light of the same wavelengths as the light source, a component that reduces friction at an interaction surface, and a component that reduces glare. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A method of multi-touch sensing, comprising the steps of:
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displaying one or more images using a display element having a viewer side and a rear side; receiving, within an optical waveguide through at least one edge surface of the optical waveguide, light emitted by a light source, the optical waveguide having a contact surface, a non-contact surface, and one or more edge surfaces, the non-contact surface facing and covering at least a portion of the viewer side of the display element; internally reflecting the received light within the optical waveguide; depressing a compliant surface overlay disposed adjacent to the optical waveguide based on an external force against a touch surface of the compliant surface overlay, the compliant surface overlay having the touch surface and a display-side surface, the display-side surface facing the contact surface of the optical waveguide and being spaced apart from the contact surface by a gap, the optical waveguide, the compliant surface overlay and the gap therebetween being configured to promote total internal reflection of light in the optical waveguide, wherein the compliant surface overlay includes a component that rejects ambient light of the same wavelengths as the light source, a component that reduces friction at an interaction surface, and a component that reduces glare; contacting the contact surface of the optical waveguide by the display-side surface of the compliant surface overlay upon depressing the compliant surface overlay; frustrating the internally reflected light within the optical waveguide upon contacting the contact surface of the optical waveguide by the display-side surface of the compliant surface overlay to cause some of the internally reflected light to escape the optical waveguide; and imaging, using at least an imaging sensor positioned opposing the non-contact surface of the optical waveguide, light escaping the optical waveguide toward the display element. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38)
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39. A multi-touch sensing display, comprising:
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a light source; an optical waveguide configured to receive light emitted by the light source and to cause at least some of the received light to undergo total internal reflection within the optical waveguide, the optical waveguide having a contact surface, a non-contact surface, and one or more edge surfaces, at least one of the one or more edge surfaces of the optical waveguide being configured to receive light emitted by the light source; a compliant surface overlay having a touch surface and a display-side surface, the display-side surface facing the contact surface of the optical waveguide so as to enable the display-side surface of the compliant surface overlay to contact the contact surface of the optical waveguide when the compliant surface overlay is physically depressed, the compliant surface overlay being spaced apart from the contact surface of the optical waveguide by a gap and being configured to; cause frustration of the total internal reflection of the received light within the optical waveguide at a contact point between the display-side surface of the compliant surface overlay and the contact surface of the optical waveguide when the display-side surface of the compliant surface overlay is physically depressed to contact the contact surface of the optical waveguide such that some of the received light undergoing total internal reflection within the optical waveguide escapes from the optical waveguide at the contact point; and operate as a diffuser for rear projection; a projector positioned opposing the non-contact surface of the optical waveguide and configured to project images that are diffused by the compliant surface overlay and made visible to a user providing touch inputs to the touch surface of the compliant surface overlay, the non-contact surface of the optical waveguide facing the projector; and an imaging sensor positioned opposing the non-contact surface of the optical waveguide and configured to detect light escaping the optical waveguide toward the projector to enable detection of touch input provided to the compliant surface overlay and discrimination between a relatively small point of contact with the compliant surface overlay and a relatively large point of contact with the compliant surface overlay, the imaging sensor being configured to detect pressure applied to the compliant surface overlay based on whether the touch input causes the relatively small point of contact with the compliant surface overlay or the relatively large point of contact with the compliant surface overlay, wherein the compliant surface overlay is a composite of multiple layers affixed to one another using index-of-refraction matching optical adhesives, and wherein the multiple layers of the compliant surface overlay comprise a layer that functions as an optical diffuser for rear projection, a layer that that provides wavelength selective shielding to mitigate interference from external ambient light, and an anti-glare layer to enhance visibility of the display.
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40. A multi-touch sensing display, comprising:
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an infrared light source; an optical waveguide configured to receive infrared light emitted by the infrared light source and to cause at least some of the received infrared light to undergo total internal reflection within the optical waveguide, the optical waveguide having a contact surface, a non-contact surface, and one or more edge surfaces, at least one of the one or more edge surfaces of the optical waveguide being configured to receive infrared light emitted by the infrared light source; a compliant surface overlay having a touch surface and a display-side surface, the display-side surface facing the contact surface of the optical waveguide so as to enable the display-side surface of the compliant surface overlay to contact the contact surface of the optical waveguide when the compliant surface overlay is physically depressed, the compliant surface overlay being spaced apart from the contact surface of the optical waveguide by a gap and being configured to; cause frustration of the total internal reflection of the received infrared light within the optical waveguide at a contact point between the display-side surface of the compliant surface overlay and the contact surface of the optical waveguide when the display-side surface of the compliant surface overlay is physically depressed to contact the contact surface of the optical waveguide such that some of the received infrared light undergoing total internal reflection within the optical waveguide escapes from the optical waveguide at the contact point; at least an imaging sensor positioned opposing the non-contact surface of the optical waveguide and configured to detect infrared light escaping the optical waveguide to enable detection of touch inputs being provided to the compliant surface overlay; a liquid crystal display panel positioned between the optical waveguide and the imaging sensor, the liquid crystal display panel being configured to display images and being transparent to infrared light so that infrared light escaping the optical waveguide passes through the liquid crystal display panel and is imaged by the imaging sensor, where the compliant surface overlay has relatively low optical diffuser properties such that images displayed by the liquid crystal display panel are visible to a user providing touch inputs to the compliant surface overlay and the non-contact surface of the optical waveguide faces and covers at least a portion of the liquid crystal display panel, wherein the compliant surface overlay comprises a layer that provides wavelength selective shielding to mitigate interference from external ambient light and an anti-glare layer to enhance display visibility. - View Dependent Claims (41, 42)
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Specification