Focusing device comprising a plurality of scatterers and beam scanner and scope device
View Patent ↗A focusing device includes a substrate and a plurality of scatterers provided at both sides of the substrate. The scatterers on the both sides of the focusing device may correct geometric aberration, and thus, a field of view (FOV) of the focusing device may be widened.
1. A focusing device comprising:
a substrate;
a first thin lens provided at a first surface of the substrate and comprising a plurality of first scatterers; and
a second thin lens provided at a second surface of the substrate and comprising a plurality of second scatterers,
wherein the plurality of first scatterers of the first thin lens are configured to correct geometric aberration of the second thin lens.
2. The focusing device of claim 1 , wherein the first and the second thin lenses are configured to allow light to form a focusing point on a focal plane.
3. The focusing device of claim 1 , wherein a phase shift of light that passes through the plurality of second scatterers decreases from a central area of the second thin lens to a peripheral area of the second thin lens.
4. The focusing device of claim 3 , wherein a phase shift of light that passes through the plurality of first scatterers decreases from a peripheral area of the first thin lens to a middle area of the first thin lens and increases from the middle area of the first thin lens to a central area of the first thin lens.
5. The focusing device of claim 2 , wherein the first and the second thin lenses are configured to change a location of the focusing point according to an angle at which the light is incident on the first surface.
6. The focusing device of claim 5 , wherein the first and the second thin lenses area configured to determine the location of the focusing point according to Equation 1:
h=f *tan θ
wherein ‘h’ is a distance between the location of the focusing point and an optical axis of the focusing device, ‘f’ is an effective focal length of the focusing device, and ‘θ’ is an angle at which the light is incident on the first surface.
7. The focusing device of claim 1 , wherein respective refractive indexes of the first and the second scatterers are greater than a refractive index of the substrate by at least 1.
8. The focusing device of claim 7 , wherein the substrate comprises at least one selected from fused silica, BK7, quartz, polymethyl methacrylate (PMMA), SU-8, and plastic, and the first and second scatterers comprise at least one selected from crystalline silicon (c-Si), polycrystalline silicon (poly Si), amorphous silicon (a-Si), Si 3 N 4 , GaP, GaAs, TiO 2 , AlSb, AlAs, AlGaAs, AlGaInP, BP, and ZnGeP 2 .
9. The focusing device of claim 1 , wherein the plurality of first and the plurality of second scatterers are configured to allow incident light within a wavelength band to form a focusing point on a focal plane.
10. The focusing device of claim 9 , wherein distances between the plurality of first scatterers and distances between the plurality of second scatterers are less than wavelengths in the wavelength band.
11. The focusing device of claim 9 , wherein respective heights of the plurality of first scatterers and respective heights of the plurality of second scatterers are less than wavelengths in the wavelength band.
12. The focusing device of claim 9 , further comprising an optical filter configured to block the incident light of wavelengths outside the wavelength band.
13. The focusing device of claim 1 , wherein at least one of respective shapes of the plurality of first and the plurality of second scatterers and respective sizes of the plurality of first and the plurality of second scatterers changes according to a thickness of the substrate.
14. The focusing device of claim 1 , wherein each of the plurality of first and the plurality of second scatterers has at least one of a cylindrical shape, an cylindroid shape, and a polyhedral pillar shape.
15. A beam scanner comprising:
an optical path modifier comprising a substrate, a first thin lens provided at a first surface of the substrate and comprising a plurality of first scatterers, and a second thin lens provided at a second surface of the substrate and comprising a plurality of second scatterers; and
a light source array spaced apart from the second surface of the substrate and comprising a plurality of light sources,
wherein the plurality of first scatterers of the first thin lens are configured to correct coma aberration of the second thin lens.
16. The beam scanner of claim 15 , wherein the optical path modifier changes a path of light emitted from the plurality of light sources according to respective locations of the light sources.
17. The beam scanner of claim 15 , wherein the optical path modifier modifies light emitted from one of the plurality of light sources into parallel rays.
18. A scope device comprising:
an object lens unit comprising a substrate;
a first thin lens provided at a first surface of the substrate and comprising a plurality of first scatterers, and a second thin lens provided at a second surface of the substrate and comprising a plurality of second scatterers; and
a light source facing the second surface of the substrate and configured to emit light on a target object,
wherein the plurality of first scatterers of the first thin lens are configured to correct coma aberration of the second thin lens.
19. The scope device of 18 , wherein light emitted by the light source has at least two wavelengths with different transmission rates with respect to the target object.
20. The scope device of claim 19 , wherein the light emitted by the light source is scattered at different locations by the target object according to wavelengths of the light emitted by the light source, and
the object lens unit is configured to change a path of the light according to the locations at which the light is scattered by the target object.