Projector including meta-lens
Provided are projectors, each including a light source configured to emit laser light, a substrate spaced apart from the light source by a distance, a pattern mask including a pattern on a first surface of the substrate, the first surface facing the light source, and a meta-lens including a plurality of first nanostructures on a second surface of the substrate, the second surface facing the first surface, the nanostructures having a shape dimension of a sub-wavelength that is less than a wavelength of light emitted from the light source.
1. A projector comprising:
a light source configured to emit laser light;
a substrate apart from the light source;
a pattern mask comprising a pattern on a first surface of the substrate, the first surface facing the light source, the pattern being configured to form a structured light; and
a first meta-lens configured to focus the structured light on a predetermined focus plane, the first meta-lens including a plurality of first nanostructures contacting a second surface of the substrate, the second surface facing the first surface, the plurality of first nanostructures having a shape dimension of a sub-wavelength that is less than a wavelength of light emitted from the light source.
2. The projector of claim 1 , wherein the pattern mask comprises a first portion which is a region where laser light is absorbed or reflected and a second portion which is a region where laser light is transmitted, and
the pattern of the pattern mask is an image pattern formed by the second portion, and the image pattern is regularly or randomly arranged so as to form the structured light.
3. The projector of claim 2 , wherein the plurality of first nanostructures receive the structured light pattern and focus the structured light pattern on a focusing plane spaced apart from the first meta-lens.
4. The projector of claim 1 , wherein the pattern mask is configured to contact the substrate.
5. The projector of claim 1 , wherein the pattern mask comprises a metal, a black matrix, or a polymer.
6. The projector of claim 1 , wherein the light source is a surface light-emitting device configured to directly emit light with respect to the pattern mask.
7. The projector of claim 6 , wherein the light source is a surface light-emitting diode.
8. The projector of claim 1 , wherein the plurality of first nanostructures comprise a material having a refractive index greater than that of a peripheral material.
9. The projector of claim 1 , further comprising a housing configured to fix the light source and the substrate, wherein the projector is an integrated module.
10. The projector of claim 1 , wherein the plurality of first nanostructures have a pitch less than a half of a wavelength of light emitted from the light source.
11. The projector of claim 1 , wherein the substrate comprises a first substrate and a second substrate which is stacked on the first substrate.
12. The projector of claim 1 , further comprising a protective layer on the second surface of the substrate to cover the meta-lens.
13. A depth recognition apparatus comprising:
the projector of claim 1 configured to irradiate structured light to an object;
a sensor configured to receive the structured light reflected by the object; and
a computation unit configured to compute a depth location of the object by comparing the structured light irradiated from the projector with the structured light received by the sensor.
14. An electronic device comprising;
the depth recognition apparatus of claim 13 ;
a processor configured to receive an information of the depth location of the object.