Apparatus and method for receiving a touch input
View Patent ↗Infrared-style touch screens are described having light emission means and light detection means along only two opposing sides of a touch input area, which are nevertheless able to detect and locate a touch object in two dimensions. Certain embodiments use an edge-blurring algorithm to determine the second coordinate, while other embodiments use a form of stereo-scopic vision to determine both coordinates by triangulation. These touch screens have minimal bezel width along two opposing sides of the touch input area, and also offer cost reductions associated with components and product assembly and manufacturing.
1. An input device comprising:
an input area to receive touch input to said input device;
an emitting system to emit first and second pluralities of energy beams across said input area, said first and second pluralities of energy beams propagating in first and second directions between a first side and a second side of said input area, where said first and second directions are angled relative to each other, and said second side opposing said first side;
a detector system to measure intensity distributions of said first and second pluralities of energy beams after said beams have traversed said input area; and
an analyzer operatively connected to said detector system to analyze plural variations in said intensity distributions from an object within said input area, and determine a position of said object along a coordinate axis between said first side and said second side, where and said variations comprise plural regions of decreased intensity in said intensity distribution,
wherein said analyzer determines plural gradients at locations within said regions of decreased intensity and thereby determines a distance between said object and said detector corresponding to said position of said object along said coordinate axis,
wherein magnitudes of said gradients decrease when said distance between said object and said detector increases,
wherein said emitting system emits said first and second pluralities of energy beams from said first side of said input area, and said detector system is disposed along said second side of said input area,
wherein said detector system comprises:
a first array of optical waveguides disposed along said second side to receive portions of said first plurality of energy beams and conduct said portions to a detector array; and
a second array of optical waveguides disposed along said second side to receive portions of said second plurality of energy beams and conduct said portions to a detector array,
wherein each of the optical waveguides terminates in an in-plane lens to focus a portion of the respective plurality of energy beams,
wherein said emitting system comprises an optical source to produce an optical signal, an optical splitting element and a transmissive body,
wherein said transmissive body comprises:
a transmissive element to receive, confine and transmit said optical signal in planar form;
a collimation element to substantially collimate said optical signal; and
a redirection element to redirect said optical signal,
wherein said transmissive, collimation and redirection elements are arranged to receive said optical signal from said optical source and transmit, collimate and redirect said optical signal to produce a substantially collimated signal in a substantially planar form, and
said optical splitting element is positioned to split said substantially collimated substantially planar signal into said first and second pluralities of energy beams, and said optical splitting element comprises a prism film or a phase mask.
2. An input device according to claim 1 , wherein each of the optical waveguides is respectively associated with an optical element that comprises a focusing element and a deflection element,
wherein said focusing element and said deflection element in combination collect and focus a portion of said first plurality of energy beams into said associated optical waveguide, and said focusing element collects and focuses a portion of said second plurality of energy beams into said associated optical waveguide.
3. An input device according to claim 1 , wherein the angle between said first and second directions is in a range from 5° to 30°.
4. An input device according to claim 1 , wherein said variations are analyzed to determine the position of said object by triangulation.
5. An input device according to claim 1 , wherein said coordinate axis intersects both said first side and said second side.
6. An input device according to claim 1 , wherein said first and second pluralities of enemy beams comprise infrared or visible light.