TIR-based optical touch systems of projection-type
First Claim
1. A touch-sensitive apparatus, comprising:
- a light transmissive panel comprising a front surface and an opposite, rear surface;
a plurality of light emitters configured to optically connect to the panel and further configured to generate light that propagates by total internal reflection inside the panel across a touch-sensitive region on the panel; and
a plurality of light detectors configured to optically connect to the panel and further configured to define a grid of propagation paths across the touch-sensitive region between pairs of light emitters and light detectors;
wherein each of said light emitters comprises a vertical-cavity surface-emitting laser (“
VCSEL”
) array, each said VCSEL array including a plurality of VCSELs configured to be driven in parallel to collectively form one light emitter; and
wherein a bandpass filter, tailored to an operating wavelength for said VCSELs, is arranged at said detectors.
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Abstract
A touch-sensitive apparatus operates by light frustration (FTIR) and comprises a light transmissive panel that defines a front surface and a rear surface, light emitters optically connected to the panel so as to generate light that propagates by total internal reflection inside the panel, and light detectors optically connected to the panel so as to define a grid of propagation paths inside the panel between pairs of light emitters and light detectors. Each of said light emitters is a VCSEL array, each said VCSEL array including a plurality of VCSELs driven in parallel to collectively form one light emitter. Preferably, each light detector is optically connected to the panel via an angular filter, tailored to pass light to the detector in an angular range in which the emitters operate.
558 Citations
14 Claims
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1. A touch-sensitive apparatus, comprising:
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a light transmissive panel comprising a front surface and an opposite, rear surface; a plurality of light emitters configured to optically connect to the panel and further configured to generate light that propagates by total internal reflection inside the panel across a touch-sensitive region on the panel; and a plurality of light detectors configured to optically connect to the panel and further configured to define a grid of propagation paths across the touch-sensitive region between pairs of light emitters and light detectors; wherein each of said light emitters comprises a vertical-cavity surface-emitting laser (“
VCSEL”
) array, each said VCSEL array including a plurality of VCSELs configured to be driven in parallel to collectively form one light emitter; andwherein a bandpass filter, tailored to an operating wavelength for said VCSELs, is arranged at said detectors. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A touch-sensitive apparatus, comprising:
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a light transmissive panel comprising a front surface and an opposite, rear surface; a plurality of light emitters configured to optically connect to the panel and further configured to generate light that propagates by total internal reflection inside the panel across a touch-sensitive region on the panel; and a plurality of light detectors configured to optically connect to the panel and further configured to define a grid of propagation paths across the touch-sensitive region between pairs of light emitters and light detectors; wherein each of said light emitters comprises a vertical-cavity surface-emitting laser (“
VCSEL”
) array, each said VCSEL array including a plurality of VCSELs configured to be driven in parallel to collectively form one light emitter;wherein an angular filter is configured to be applied to an outcoupling region of the light transmissive panel and is further configured to transmit the propagating light only within a confined range of angles with respect to the normal of the outcoupling region; and wherein the confined range extends from a lower angle limit θ
min to an upper angle limit θ
max, wherein the lower angle limit θ
min is equal to or larger than a critical angle θ
c, which is given by θ
c=arcsin( 1/npanel), with npanel being the refractive index of the light transmissive panel at the outcoupling region.
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14. A touch-sensitive apparatus, comprising:
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a light transmissive panel comprising a front surface and an opposite, rear surface; a plurality of light emitters configured to optically connect to the panel and further configured to generate light that propagates by total internal reflection inside the panel across a touch-sensitive region on the panel; and a plurality of light detectors configured to optically connect to the panel and further configured to define a grid of propagation paths across the touch-sensitive region between pairs of light emitters and light detectors; wherein each of said light emitters comprises a vertical-cavity surface-emitting laser (“
VCSEL”
) array, each said VCSEL array including a plurality of VCSELs configured to be driven in parallel to collectively form one light emitter;wherein an angular filter is configured to be applied to an outcoupling region of the light transmissive panel and is further configured to transmit the propagating light only within a confined range of angles with respect to the normal of the outcoupling region; and wherein the angular filter is configured as a dielectric multilayer structure.
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Specification