Optical lens, optical system and method of manufacturing optical lens
An optical lens adapted to be disposed on a transmission path of a light beam is provided. The optical lens includes a plurality of lenticular lens units extending along the same direction, and the lenticular lens units are disposed side by side along a direction perpendicular to the extension direction thereof, wherein each of the lenticular lens units has a height relative to a bottom surface of the optical lens, adjacent two of the lenticular lens units have a height difference D therebetween, and the optical lens satisfies D ≥ 2 ln ( 2 ) π n λ 2 Δλ , wherein n represents a refractive index of the optical lens, λ represents a central wavelength of the light beam, and Δλ represents a spectral bandwidth of the light beam. In addition, an optical system and a method of manufacturing an optical lens are also mentioned.
1. An optical lens adapted to be disposed on a transmission path of a light beam, the optical lens comprising:
a plurality of lenticular lens units extending along a same direction, the lenticular lens units being disposed side by side along a direction perpendicular to the extension direction thereof, and each of the lenticular lens units comprising a cylindrical lenticular lens extending in a direction of a central axis thereof, wherein each of the lenticular lens units has a height relative to a bottom surface of the optical lens, any adjacent two of the lenticular lens units have a height difference therebetween, and the height difference is not less than a minimum height difference D defined by an equation:
D
=
2
ln
(
2
)
π
n
λ
2
Δλ
,
wherein n represents a refractive index of the optical lens, λ represents a central wavelength of the light beam, and Δλ represents a spectral bandwidth of the light beam.
2. The optical lens of claim 1 , wherein the lenticular lens units comprise a plurality of first lenticular lens units and a plurality of second lenticular lens units, the first lenticular lens units and the second lenticular lens units are alternately arranged, the first lenticular lens units have a same first height and the second lenticular lens units have a same second height.
3. The optical lens of claim 1 , wherein the lenticular lens units comprise a plurality of first lenticular lens units and a plurality of second lenticular lens units, the first lenticular lens units and the second lenticular lens units are alternately arranged, the first lenticular lens units have a same first height and the second lenticular lens units have different heights from each other.
4. The optical lens of claim 1 , wherein each of the lenticular lens units has a curved surface opposing the bottom surface, and the curved surfaces have the same curvature.
5. The optical lens of claim 1 , wherein each of the lenticular lens units has a curved surface opposing the bottom surface, and the curved surfaces have different curvatures.
6. A method of manufacturing the optical lens of claim 1 , comprising:
providing a plurality of lenticular lens units independent of each other; and
sticking the lenticular lens units independent of each other together by using an optically clear adhesive, so as to form the optical lens.
7. An optical system, comprising:
a light source adapted to emit a light beam; and
an optical lens disposed on a transmission path of the light beam, the optical lens comprising:
a plurality of lenticular lens units extending along a same direction, the lenticular lens units being disposed side by side along a direction perpendicular to the extension direction thereof, and each of the lenticular lens units comprising a cylindrical lenticular lens extending in a direction of a central axis thereof, wherein each of the lenticular lens units has a height relative to a bottom surface of the optical lens, any adjacent two of the lenticular lens units have a height difference therebetween, and the height difference is not less than a minimum height difference D defined by an equation:
D
=
2
ln
(
2
)
π
n
λ
2
Δλ
,
wherein n represents a refractive index of the optical lens, λ represents a central wavelength of the light beam, and Δλ represents a spectral bandwidth of the light beam.
8. The optical system of claim 7 , wherein the lenticular lens units of the optical lens comprise a plurality of first lenticular lens units and a plurality of second lenticular lens units, the first lenticular lens units and the second lenticular lens units are alternately arranged, the first lenticular lens units have a same first height and the second lenticular lens units have a same second height.
9. The optical system of claim 7 , wherein the lenticular lens units of the optical lens comprise a plurality of first lenticular lens units and a plurality of second lenticular lens units, the first lenticular lens units and the second lenticular lens units are alternately arranged, the first lenticular lens units have a same first height and the second lenticular lens unit have different heights from each other.
10. The optical system of claim 7 , wherein each of the lenticular lens units has a curved surface opposing the bottom surface, and the curved surfaces have the same curvature.
11. The optical system of claim 7 , wherein each of the lenticular lens units has a curved surface opposing the bottom surface, and the curved surfaces have different curvatures.
12. A method of manufacturing the optical lens of claim 1 , comprising:
providing a mold, the mold having a cavity having a shape corresponding to the lenticular lens units;
filling a lens material into the cavity;
curing the lens material; and
separating the cured lens material from the mold.
13. The method of claim 12 , wherein a method of providing the mold comprises:
providing a plurality of mold units independent of each other, the mold units respectively having a partial mold surface corresponding to the lenticular lens units; and
disposing the mold units side by side to constitute the mold.
14. The method of claim 12 , wherein a method of providing the mold comprises:
providing a plurality of mold core units independent of each other, the mold core units respectively having the same shapes and sizes as the lenticular lens units;
disposing the mold core units side by side, and performing molding to form the mold.