Optical reflective encoder with multi-faceted flat-faced lens
First Claim
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1. A reflective optical encoder, comprising:
- a substrate having a top surface with opposing first and second sides;
a light emitter coupled to the first side;
a light detector coupled to the second side;
a multi-faceted lens comprising first and second top flat faces, the first top flat face being located over the light emitter and being tilted with respect to the top surface, and the second top flat face being formed over the light detector and being parallel to the top surface; and
a plurality of diffractive optical elements comprising first and second members and each of the first and second members comprising a major surface;
wherein the first member of the plurality of diffractive optical elements is disposed on the first top flat face of the multi-faceted lens and the second member of the plurality of diffractive optical elements is disposed on the second top flat face of the multi-faceted lens;
wherein the major surface of the first member of the plurality of diffractive optical elements is not parallel and tilted with respect to the major surface of the second member of the plurality of diffractive optical elements and to the top surface of the substrate;
wherein the multi-faceted lens is configured to direct light towards a code scale for reflection therefrom, the code scale being located operably in respect of the lens such that at least a portion of the light reflected from the code scale is directed towards the second face for detection by the light detector;
wherein the first member of the plurality of diffractive optical elements is configured to provide light-collimating functionality for light emitted by the light emitter.
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Abstract
Disclosed are various embodiments of high-speed, high-performance, low-noise, low-cost, compact, optical encoders having a multi-faceted flat-faced lens is disposed over the light emitters and light detectors thereof. Disclosed also are various means for preventing undesired stray light from reaching light detectors incorporated therein. Structures employed to block stray light in the optical encoders include light barriers, air gap trenches, and coatings disposed between first and second sides of a substrate of the encoder. Methods of making such optical encoders are also disclosed.
19 Citations
20 Claims
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1. A reflective optical encoder, comprising:
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a substrate having a top surface with opposing first and second sides; a light emitter coupled to the first side; a light detector coupled to the second side; a multi-faceted lens comprising first and second top flat faces, the first top flat face being located over the light emitter and being tilted with respect to the top surface, and the second top flat face being formed over the light detector and being parallel to the top surface; and a plurality of diffractive optical elements comprising first and second members and each of the first and second members comprising a major surface; wherein the first member of the plurality of diffractive optical elements is disposed on the first top flat face of the multi-faceted lens and the second member of the plurality of diffractive optical elements is disposed on the second top flat face of the multi-faceted lens; wherein the major surface of the first member of the plurality of diffractive optical elements is not parallel and tilted with respect to the major surface of the second member of the plurality of diffractive optical elements and to the top surface of the substrate; wherein the multi-faceted lens is configured to direct light towards a code scale for reflection therefrom, the code scale being located operably in respect of the lens such that at least a portion of the light reflected from the code scale is directed towards the second face for detection by the light detector; wherein the first member of the plurality of diffractive optical elements is configured to provide light-collimating functionality for light emitted by the light emitter. - View Dependent Claims (2, 3)
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4. A reflective optical encoder, comprising:
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a top surface with opposing first and second sides, the top surface being substantially parallel to a horizontal plane; a code scale disposed adjacent to the top surface; a light emitter disposed on the first side of the top surface, and configured to emit light therefrom, the light emitter being configured to emit a substantial amount of light along a direction normal to the horizontal plane towards the code scale; a light detector disposed on the second side of the top surface; a multi-faceted lens being integrally formed over the light emitter and the light detector such that no air gap is located between the light emitter and the lens, wherein the multi-faceted lens comprises a first face directly located over the light emitter, and a second face directly located over the light detector, and wherein the first and second faces are interconnected on one side and at least one of the first and second faces is tilted with respect to the horizontal plane, the multi-faceted lens including; and a plurality of diffractive optical elements comprising first and second members and each of the first and second members comprising a major surface, wherein the first member of the plurality of diffractive optical elements is disposed on the first face, wherein the second member of the plurality of diffractive optical elements is disposed on the second face, wherein a major surface of the first member of the plurality of diffractive optical elements is not parallel and tilted with respect to the horizontal plane, and wherein the first member of the plurality of diffractive optical elements provides light-collimating functionality for light emitted by the light emitter, and wherein the code scale is located operably in respect of the multi-faceted lens such that at least a portion of the light reflected from the code scale is directed towards the second face and refracted through portions of the multi-faceted lens for detection by the light detector. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. An encoder system, comprising:
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an emitter configured to emit light; a receiver configured to receive reflected light that is emitted from the emitter; a substrate having a first surface extending along a first plane, wherein the emitter and the receiver are disposed on the first surface; a code scale configured to receive the light from the emitter, wherein the code scale is configured to reflect a portion of the light back towards the receiver, the code scale intersecting a normal axis that is between the emitter and the receiver, the normal axis being substantially perpendicular to the first plane so as to divide the substrate to a first side having the emitter and a second side having the receiver; a multi-faceted lens having a first face, a second face and a body, wherein the body is configured to cover the first surface of the substrate, the emitter, and the receiver, wherein the first face is located over the emitter on the first side such that the first face intercepts the light emitted from the emitter, wherein the second face is located over the receiver on the second side such that the second face intercepts the light reflected from the code scale; and a first diffractive optical element disposed on the first face; a second diffractive optical element disposed on the second face, wherein the first diffractive optical element comprises a major surface that is not parallel and is tilted with respect to a major surface of the second diffractive optical element, and wherein the first diffractive optical element provides light-collimating functionality for light emitted by the emitter. - View Dependent Claims (18, 19, 20)
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Specification