OPTICAL SYSTEM
An optical system is provided, including a light source, a fixed portion, an optical assembly, and a driving assembly. The light source is used for generating light. The optical assembly has an equivalent focal length to the light. The optical assembly includes a first optical element and a second optical element. The driving assembly is used for driving the second optical element to move relative to the first optical element. When the second optical element is at a first position, the equivalent focal length is a first focal length. When the second optical element is at a second position, the equivalent focal length is a second focal length. The first focal length and the second focal length are different.
1 . An optical system, comprising:
a light source used for generating light;
a fixed portion;
an optical assembly having an equivalent focal length to the light and comprising a first optical element and a second optical element; and
a driving assembly used for driving the second optical element to move relative to the first optical element;
wherein:
when the second optical element is at a first position, the equivalent focal length is a first focal length;
when the second optical element is at a second position, the equivalent focal length is a second focal length;
the first focal length and the second focal length are different.
2 . The optical system as claimed in claim 1 , wherein:
the first optical element and the second optical element are arranged along a main axis;
the driving assembly is used for driving the second optical element to move in directions perpendicular to the main axis.
3 . The optical system as claimed in claim 2 , wherein:
a gap is between the first optical element and the second optical element;
the gap is less than 0.1 mm.
4 . The optical system as claimed in claim 3 , wherein the first optical element comprises:
a first surface; and
a first structure disposed on the first surface.
5 . The optical system as claimed in claim 4 , wherein the first surface and the main axis are perpendicular.
6 . The optical system as claimed in claim 5 , wherein:
the first structure comprises a plurality of first protrusions;
the first structure has periodicity.
7 . The optical system as claimed in claim 6 , wherein the first optical element further comprises:
a first substrate;
a first dielectric layer disposed on the first substrate, wherein the first dielectric layer has a first opening;
a first optical unit disposed in the first opening; and
a first resilient unit disposed in the first opening and connecting the first dielectric layer and the first optical unit.
8 . The optical system as claimed in claim 7 , wherein:
the first surface is a surface of the first optical unit;
the first structure is disposed on the first optical unit.
9 . The optical system as claimed in claim 8 , wherein:
a height of the first structure is less than 1 μm;
the first resilient unit comprises metal.
10 . The optical system as claimed in claim 9 , wherein the second optical element comprises:
a second surface; and
a second structure disposed on the second surface;
wherein the second surface and the main axis are perpendicular.
11 . The optical system as claimed in claim 10 , wherein:
the second structure comprises a plurality of second protrusions;
the second structure has periodicity.
12 . The optical system as claimed in claim 11 , wherein the second optical element further comprises:
a second substrate;
a second dielectric layer disposed on the second substrate, wherein the second dielectric layer has a second opening;
a second optical unit disposed in the second opening; and
a second resilient unit disposed in the second opening and connecting the second dielectric layer and the second optical unit.
13 . The optical system as claimed in claim 12 , wherein:
the second surface is a surface of the second optical unit;
the second structure is disposed on the second optical unit.
14 . The optical system as claimed in claim 13 , wherein:
a height of the second structure is less than 1 μm;
the second resilient unit comprises metal.
15 . The optical system as claimed in claim 14 , wherein the first surface and the second surface face an identical direction.
16 . The optical system as claimed in claim 14 , wherein the first surface and the second surface face opposite directions.
17 . The optical system as claimed in claim 14 , wherein:
the first optical unit further comprises:
a third surface on the first optical unit and facing an opposite direction from the first surface; and
a third structure disposed on the third surface;
the second optical unit further comprises:
a fourth surface on the second optical unit and facing an opposite direction from the second surface; and
a fourth structure disposed on the fourth surface.
18 . The optical system as claimed in claim 17 , wherein:
the third surface is perpendicular to the main axis;
the third structure comprises a plurality of third protrusions;
the third structure has periodicity;
a height of the third structure is less than 1 μm.
19 . The optical system as claimed in claim 18 , wherein:
the fourth surface is perpendicular to the main axis;
the fourth structure comprises a plurality of fourth protrusions;
the fourth structure has periodicity;
a height of the fourth structure is less than 1 μm.
20 . The optical system as claimed in claim 14 , wherein:
the second optical element comprises a first region and a second region;
the second protrusions have a first height and a first gap in the first region;
the second protrusions have a second height and a second gap in the second region;
the first height and the second height are different;
the first gap and the second gap are different.