Eye tracker comprising a shadow mask and electronic device
An eye tracker comprises a shadow mask, a light emitting element, and a detection region at a first side of the shadow mask. The light emitting element emits electromagnetic radiation towards an eye arranged at a second side of the shadow mask, which comprises portions that are transparent for the electromagnetic radiation and portions that are opaque for the electromagnetic radiation, the transparent portions having a maximum width measured in a first horizontal direction. The detection region comprises a pixel array and is configured to receive electromagnetic radiation emitted by the light emitting element, reflected by a cornea of the eye, and transmitted by the shadow mask. A maximum distance P S between adjacent pixels and the maximum width w A of the transparent portions satisfy the following formula: 0.9* w A ≤P S ≤1.25* w A , the maximum distance between adjacent pixels being measured in the first horizontal direction.
1 . An eye tracker comprising:
a shadow mask;
a light emitting element; and
a detection region arranged at a first side of the shadow mask;
the light emitting element being configured to emit electromagnetic radiation towards an eye arranged at a second side of the shadow mask, the shadow mask comprising transparent portions being transparent for the electromagnetic radiation and opaque portions being opaque for the electromagnetic radiation, the transparent portions having a maximum width measured in a first horizontal direction;
the detection region being configured to receive electromagnetic radiation emitted by the light emitting element, reflected by a cornea of the eye and transmitted by the shadow mask, the detection region comprising a pixel array comprising a plurality of pixels, wherein a maximum distance P S between adjacent pixels and the maximum width w A of the transparent portions satisfy the following formula:
0.9* w A ≤P S ≤1.25* w A ,
the maximum distance between adjacent pixels being measured in the first horizontal direction.
2 . The eye tracker according to claim 1 , wherein the distance between adjacent pixels is smaller than a projected minimum lateral displacement of electromagnetic radiation reflected by the cornea due to an eye movement.
3 . The eye tracker according to claim 2 , wherein the distance between adjacent pixels is less than 100 μm.
4 . The eye tracker according to claim 1 , wherein an optical distance between the detection region and the shadow mask is less than 10 mm.
5 . The eye tracker according to claim 1 , wherein the detection region and the light emitting element are arranged on a common carrier.
6 . The eye tracker according to claim 5 , comprising a plurality of light emitting elements, the light emitting elements being arranged in a region outside the pixel array.
7 . The eye tracker according to claim 1 , wherein the opaque portions of the shadow mask are transparent for visible light.
8 . The eye tracker according to claim 1 , further comprising a processing unit configured to determine an eye movement from signals received by the detection portion.
9 . The eye tracker according to claim 8 , wherein the processing unit is further configured to perform user authentication based on the signals received by the detection portion, the processing unit being configured to identify periocular features.
10 . The eye tracker according to claim 1 , wherein the shadow mask is arranged at a first main surface of a lens and the detection region is arranged at a second main surface of a lens.
11 . The eye tracker according to claim 1 , wherein the shadow mask and the detection region are arranged at a first main surface of a lens, further comprising a buffer material between the shadow mask and the detection region.
12 . An electronic device comprising the eye tracker according to claim 1 .
13 . The electronic device according to claim 12 , further comprising a display element emitting visible light, the eye tracker being arranged on a light emission side of the display element between the display element and the eye.
14 . The electronic device according to claim 12 , being selected from smart glasses and a head-mounted display.