Compact eye imaging and eye tracking apparatus

An eye tracking system, comprising:

• 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 configured to reflect light from an ocular object located about the first optical axis off of an interior side of the second surface, off of an interior side of the first surface, being an exterior surface that includes a highly reflective coating, and through the third surface, and the imaging system having conjugate points at the sensor and the ocular object such that the ocular object is imaged by the imaging system on the optical sensor;
• 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.

An optical system for eye tracking, comprising:

• 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 sensor and the ocular object are located at conjugate points of the imaging system;
• and
• wherein the ocular object is an iris.

An optical system for eye tracking, comprising:

• 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,
• wherein, the prism is configured such that an ocular object positioned about the first optical axis at a first conjugate point of the imaging system is imaged by the imaging system onto the sensor, which is situated at a second conjugate point of the imaging system, through the prism,
• 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.