Compact eye imaging and eye tracking apparatus
First Claim
Patent Images
1. An optical system for eye tracking, comprising:
- a prism having a first, second and third surface, the prism having a first optical axis intersecting the first surface, and a second optical axis intersecting and approximately orthogonal to the third surface;
an imaging system comprising a lens having at least one powered surface and a sensor arranged along the second optical axis,wherein, the first, second and third surfaces of the prism are arranged to reflect light received by the prism from an ocular object positioned about the first optical axis through the imaging system and onto the sensor through the prism, the imaging system has sufficient optical power to image the ocular object onto the sensor;
wherein the prism is configured such that light from an ocular object positioned about the first optical axis enters the prism at the first surface and exits the prism through the third surface prior to being imaged by the imaging system onto the sensor, so that the ocular object is imaged onto the sensor form an on-axis position;
wherein the prism is configured such that light from an ocular object positioned about the first optical axis entering the prism along the first axis reflects off an interior side of the second surface and reflects off an interior side of the first surface before exiting the prism through the third surface, andwherein the first surface is an exterior surface that includes a highly reflective coating for light within a predetermined wavelength range incident on an interior side of the first surface, andwherein the ocular object is an iris.
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Abstract
An optical system for eye tracking is disclosed. The system includes a light guiding prism that guides light from an ocular object to an imaging system through multiple internal reflections. The light guiding prism may include one or more freeform surfaces having optical power.
68 Citations
28 Claims
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1. An optical system for eye tracking, comprising:
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a prism having a first, second and third surface, the prism having a first optical axis intersecting the first surface, and a second optical axis intersecting and approximately orthogonal to the third surface; an imaging system comprising a lens having at least one powered surface and a sensor arranged along the second optical axis, wherein, the first, second and third surfaces of the prism are arranged to reflect light received by the prism from an ocular object positioned about the first optical axis through the imaging system and onto the sensor through the prism, the imaging system has sufficient optical power to image the ocular object onto the sensor; wherein the prism is configured such that light from an ocular object positioned about the first optical axis enters the prism at the first surface and exits the prism through the third surface prior to being imaged by the imaging system onto the sensor, so that the ocular object is imaged onto the sensor form an on-axis position; wherein the prism is configured such that light from an ocular object positioned about the first optical axis entering the prism along the first axis reflects off an interior side of the second surface and reflects off an interior side of the first surface before exiting the prism through the third surface, and wherein the first surface is an exterior surface that includes a highly reflective coating for light within a predetermined wavelength range incident on an interior side of the first surface, and wherein the ocular object is an iris. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. An eye tracking system comprising:
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an optical sensor; an imaging system; a prism having a first, second and third surface, the prism having a first optical axis approximately orthogonal to the first surface, and a second optical axis approximately orthogonal to the third surface, the prism'"'"'s first, second and third surfaces arranged to receive light from an ocular object located about the first optical axis through the second surface, reflect said light off of an interior side of the second surface, further reflect said light off of an interior side of the first surface, being an exterior surface that includes a highly reflective coating, and provide said light through the third surface, the imaging system having sufficient optical power to image the ocular object onto the optical sensor, and the prism being arranged so that the ocular object is imaged onto the sensor from an on-axis position; a programmable computer processor in electronic communication with the optical sensor, and a non-transitory computer readable medium in electronic communication with the programmable computer processor, the non-transitory computer readable medium having computer executable instructions encoded thereon to cause the programmable processor to recognize the position of an image of the ocular object on the sensor, and from a determination of the position, determine a direction in which an eye being measured is pointing; and wherein the ocular object is an iris. - View Dependent Claims (22)
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23. An optical system for eye tracking, comprising:
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an optical sensor; an imaging system; a prism having a first, second and third surface, the first and second surfaces having a highly reflective coating, the first surface being an exterior surface, wherein the prism is arranged such that light entering the prism from an ocular object undergoes a reflection off an interior side of the second surface, an interior side of the first surface of the prism, and another reflection off an interior side of the second surface prior to exiting the prism to be focused by the imaging system; wherein the imaging system has sufficient optical power to age the ocular object onto the sensor; wherein the prism is arranged so that the ocular object is imaged onto the sensor from an on-axis position; wherein the ocular object is an iris. - View Dependent Claims (24)
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25. An optical system for eye tracking, comprising:
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a prism having a first planar surface, a second planar surface and a third surface, the prism having a first optical axis intersecting the first surface, and a second optical axis intersecting and approximately orthogonal to the third surface; an imaging system and a sensor arranged along the second optical axis external to the third surface of the prism, wherein, the surfaces of the prism are arranged to receive light from an ocular object positioned about the first optical axis and direct said light through the prism to the sensor via the imaging system, which has sufficient optical power to image the ocular object onto the sensor, wherein the prism is configured such that light from an ocular object positioned about the first optical axis enters the prism at the first surface and exits the prism through the third surface prior to being imaged by the imaging system onto the sensor; wherein the prism is configured such that light from an ocular object positioned about the first optical axis entering the prism along the first axis reflects off an interior side of the second surface and reflects off an interior side of the first surface before exiting the prism through the third surface; and wherein the ocular object is an iris. - View Dependent Claims (26, 27)
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28. An optical system for eye tracking, comprising:
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a prism having a first, second and third surface, the prism having a first optical axis intersecting the first surface; and
a second optical axis intersecting and approximately orthogonal to the third surface;an imaging system comprising a lens having at least one powered surface and a sensor arranged along the second optical axis, wherein, the first, second and third surfaces of the prism are arranged to reflect light received by the prism from an ocular object positioned about the first optical axis through the imaging system and onto the sensor through the prism, and the imaging system has sufficient optical power to image the ocular object onto the sensor; wherein the prism is configured such that light from an ocular object positioned about the first optical axis enters the prism at the first surface and exits the prism through the third surface prior to being imaged by the imaging system onto the sensor; wherein the prism is configured such that light from an ocular object positioned about the first optical axis entering the prism along the first axis reflects off an interior side of the second surface and reflects off an interior side of the first surface before exiting the prism through the third surface, and wherein the first surface is an exterior surface that includes a highly reflective coating for light within a predetermined wavelength range incident on an interior side of the first surface, and wherein the ocular object is an iris.
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Specification