Lamp unit and vehicle headlamp using the same
AssigneeKoito Manufacturing Co., Ltd.
InventorMasashi Tatsukawa
Life of this patent
Estimating the term…
Abstract
A lamp unit has a semiconductor light emitting chip 24a and a translucent member 22 which subjects light emitted from the chip 24a to be reflected by front surface 22a and then by rear surface 22b to exit from the front surface 22a. Chip 24a is arranged to face forward such that a lower end thereof crosses an optical axis Ax of the lamp unit 20 at right angles. The front surface 22a of the translucent member 22 is formed from a plane orthogonal to the optical axis Ax, and an optical axis region 22a1 of the front surface is subjected to mirror surface treatment. A rear surface 22b of the translucent member 22 is formed using a paraboloid of rotation whose focal point is a position having symmetry with an illumination center of the chip 24a. The rear surface is subjected to mirror surface treatment.
Claims20
A lamp unit, in a vehicle headlamp, for forming a linear portion of a cut-off line at an upper end of a light distribution pattern, the lamp unit comprising:
- a light source formed from a semiconductor light-emitting element having a light-emitting chip whose one side extends linearly;
- and
- a translucent member disposed so as to allow entry of light originating from said light source, wherein:
- said one side of said light emitting chip crosses an optical axis of said lamp unit at right angles;
- said one side of said light-emitting chip is aligned at a lower end section of said light-emitting chip;
- said translucent member is configured so as to subject incident light emitted from said light source to be reflected on a front surface of said translucent member and then reflected on a rear surface of said translucent member to exit from said front surface of said translucent member;
- a front surface of said translucent member is formed from a plane orthogonal to said optical axis;
- a rear surface of said translucent member comprises a light reflection control surface formed using a reference surface defined by a paraboloid of rotation whose focal point is a position having symmetry with an illumination center of said light source with reference to said front surface of said translucent member;
- and
- an area of said front surface of said translucent member located in the vicinity of said optical axis is subjected to mirror surface treatment, and a rear surface of said translucent member is subjected to mirror surface treatment.
A plurality of lamp units in a vehicle headlamp for forming linear portions of cut-off lines at an upper end of a light distribution pattern, the plurality of lamp units each comprising:
- a light source formed from a semiconductor light-emitting element having a light-emitting chip whose one side extends linearly;
- and
- a translucent member disposed so as to allow entry of light originating from said light source, wherein:
- said one side of said light emitting chip crosses an optical axis of said lamp unit at right angles;
- said one side of said light-emitting chip is aligned at a lower end section of said light-emitting chip;
- said translucent member is configured so as to subject incident light emitted from said light source to be reflected on a front surface of said translucent member and then reflected on a rear surface of said translucent member to exit from said front surface of said translucent member;
- a front surface of said translucent member is formed from a plane orthogonal to said optical axis;
- a rear surface of said translucent member comprises a light reflection control surface formed using a reference surface defined by a paraboloid of rotation whose focal point is a position having symmetry with an illumination center of said light source with reference to said front surface of said translucent member;
- an area of said front surface of said translucent member located in the vicinity of said optical axis is subjected to mirror surface treatment, and a rear surface of said translucent member is subjected to mirror surface treatment;
- a first one of the plurality of said lamp units is configured as a horizontal cut-off line formation lamp unit having, as said light source, a light source arranged such that one side of said light-emitting chip extends horizontally;
- and
- a second one of the plurality of said lamp units is configured as an oblique cut-off line formation lamp unit in which said one side of said light-emitting chip extends in a direction tilted at a angle with respect to a horizontal direction.
Dependencies are inferred from the claim text.