Headlamp for vehicle

• US 6,882,110 B2
• Filed: 09/02/2003
• Issued: 04/19/2005
• Est. Priority Date: 09/03/2002
• Status: Expired due to Fees

• Current Assignee: Koito Manufacturing Company Limited
• Original Assignee: Koito Manufacturing Company Limited
• Inventors: Ishida, Hiroyuki, Tatsukawa, Masashi, Sazuka, Kiyoshi
• Primary Examiner(s): Vo, Tuyet
• Assistant Examiner(s): Alemu, Ephrem
• Application Number:
  US10/652,243
• Publication Number:
  US 20040125614A1
• Time in Patent Office: 595 Days
• Field of Search: 315/77, 315/82, 315/76, 362543-545, 362/538, 362/539, 362/517, 362/507, 362/459, 362/800
• US Class Current: 315/82
• CPC Class Codes: B60Q 1/04 the devices being headlights
• CPC Class Codes: F21S 41/143 the main emission direction of the LED being parallel to the optical axis of the illuminating device
• CPC Class Codes: F21S 41/148 the main emission direction of the LED being perpendicular to the optical axis
• CPC Class Codes: F21S 41/153 arranged in a matrix
• CPC Class Codes: F21S 41/336 with discontinuity at the junction between adjacent areas
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: Y10S 362/80 Light emitting diode

Abstract

A headlamp having a plurality of lighting units using light emitting diodes as light sources. A cutoff line forming unit, hot zone forming units, and a diffusion region forming unit are used as these lighting units. Consequently, a light distribution pattern for a low beam having a desirable pattern shape and light intensity distribution can be obtained as the synthetic light distribution pattern of light distribution patterns formed by the irradiation of a light from these three kinds of lighting units.

Claims

1. A headlamp for a vehicle which is constituted to form a light distribution pattern for a low beam, comprising:

a plurality of lighting units using semiconductor light emitting elements as light sources,

wherein a cutoff line forming unit for carrying out a light irradiation to form a cutoff line of the light distribution pattern for a low beam, a hot zone forming unit for carrying out a light irradiation to form a hot zone of the light distribution pattern for a low beam and a diffusion region forming unit for carrying out a light irradiation to form a diffusion region of the light distribution pattern for a low beam are used as the lighting units;

wherein the cutoff line forming unit, the hot zone forming unit and the diffusion region forming unit are provided in three stages;

said three stages being an upper stage, lower stage, and middle stage; and

said cutoff line forming unit is positioned in the middle stage.

2. The headlamp for a vehicle according to claim 1, wherein the cutoff line forming unit includes a lighting unit of a projector type which is constituted to reflect a light emitted from a light source to be converged forward by a reflector and to irradiate the reflected light forward from the lighting unit through a projection lens provided in a forward part of the reflector.

3. The headlamp for a vehicle according to claim 1, wherein the hot zone forming unit includes a lighting unit of a direct projection type which is constituted to irradiate a direct light emitted from the light source forward from the lighting unit through a condenser lens provided in a forward part of the light source.

4. The headlamp for a vehicle according to claim 1, wherein the diffusion region forming unit includes a lighting unit of a reflection type which is constituted to reflect a light emitted from the light source forward from the lighting unit by the reflector.

5. The headlamp for a vehicle according to claim 1, wherein the cutoff line forming unit includes a lighting unit of a projector type which is constituted to reflect a light emitted from a light source to be converged forward by a reflector and to irradiate the reflected light forward from the lighting unit through a projection lens provided in a forward part of the reflector,

the hot zone forming unit includes a lighting unit of a direct projection type which is constituted to irradiate a direct light emitted from the light source forward from the lighting unit through a condenser lens provided in a forward part of the light source, and

the diffusion region forming unit includes a lighting unit of a reflection type which is constituted to reflect a light emitted from the light source forward from the lighting unit by the reflector.

6. A headlamp, comprising:

a plurality of lighting units operable to form a light distribution pattern, the plurality of lighting units comprising;

a cutoff line forming unit operable to carry out a light irradiation to form a cutoff line of the light distribution pattern;

a hot zone forming unit operable to carry out a light irradiation to form a hot zone of the light distribution pattern; and

a diffusion region forming unit operable to carry out a light irradiation to form a diffusion region of the light distribution pattern;

wherein the cutoff line forming unit, the hot zone forming unit and the diffusion region forming unit are provided in three stages;

said three stages being an upper stage, lower stage, and middle stage; and

said cutoff line forming unit is positioned in the middle stage.

7. The headlamp according to claim 6, wherein the plurality of lighting units include semiconductor light emitting elements as light sources.