Head lamp for car
Disclosed is a head lamp for a car having asymmetric magnifications for upper, lower, left, and right lens standards, and the head lamp includes: a light source; and an aspheric lens disposed in a front direction of the light source, and configured to have different horizontal and vertical magnifications.
1. A head lamp for a car, comprising:
a light source; and
an aspheric lens disposed in front of the light source, and configured to have different magnifications in first and second directions,
wherein the aspheric lens has an aspherical surface Z that satisfies the following equation,
Z
=
C
X
X
2
+
C
X
Y
2
1
+
1
-
[
1
+
K
X
]
C
X
2
X
2
-
(
1
+
K
Y
c
Y
2
Y
2
)
+
∑
N
=
2
∞
10
A
2
N
[
(
1
-
B
2
N
)
X
2
+
(
1
+
B
2
N
)
Y
2
]
N
,
where X is a coordinate of the aspherical surface in the first direction, Y is a coordinate of the aspherical surface in the second direction, C x is a curvature in the first direction, C Y is a curvature in the second direction, K x is a conic constant in the first direction, K Y is a conic constant in the second direction A 2N is a coefficient of a hi h order term of a first aspherical surface, and B 2N is a coefficient of a high order term of a second aspherical surface.
2. The head lamp of claim 1 , wherein the light source is a light emitting diode (LED) device.
3. The head lamp of claim 1 , wherein the aspheric lens is an anamorphic lens.
4. The head lamp of claim 1 , wherein the light source moves from a focus of the aspheric lens by 2 mm or more in the second direction to emit light.