Vehicular headlamp

• US 20040174712A1
• Filed: 02/25/2004
• Published: 09/09/2004
• Est. Priority Date: 03/06/2003
• Status: Active Grant

• Current Assignee: Koito Manufacturing Company Limited
• Original Assignee: Koito Manufacturing Company Limited
• Inventors: Yagi, Seiichiro
• Granted Patent: US 7,114,828 B2
• Time in Patent Office: Days
• US Class Current: 362/475
• CPC Class Codes: B60Q 1/14 having dimming means
• CPC Class Codes: F21S 41/13 Ultraviolet light; Infrared light
• CPC Class Codes: F21S 41/148 the main emission direction of the LED being perpendicular to the optical axis
• CPC Class Codes: F21S 41/151 arranged in one or more lines
• CPC Class Codes: F21S 41/18 Combination of light sources of different types or shapes
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]

Abstract

A vehicular headlamp used for a vehicle, includes an infrared light source for generating red light and infrared light, a visible light source for generating visible light whose wavelength is different from that of the red light, an optical system for emitting the red light and visible light towards a substantially same emission area in front of the vehicle and a lighting circuit for turning on the infrared light and visible light sources with the strength in order that the chromaticity in the emission area based on the red light and visible light can correspond to white light within a predetermined range in chromaticity coordinates.

Claims

1. A vehicular headlamp used for a vehicle, comprising:

an infrared light source for generating red light and infrared light;

a visible light source for generating visible light, of which wavelength is different from that of said red light;

an optical system for emitting said red light and visible light towards a substantially same emission area in front of said vehicle; and

a lighting circuit for turning on said infrared light and visible light sources with strength in order that chromaticity in said emission area based on said red light and visible light can correspond to white light within a predetermined range in chromaticity coordinates.

2. A vehicular headlamp as claimed in claim 1, wherein said infrared light source comprises a semiconductor infrared light emitting element for generating said red light and infrared light, and

said visible light source comprises a semiconductor white light emitting source for generating said white light.

3. A vehicular headlamp as claimed in claim 1, wherein said lighting circuit turns on said infrared light and visible light sources with strength in order that an X-coordinate of said chromaticity in said emission area can be within a range of 0.450 to 0.500 and a Y-coordinate thereof can be within a range of 0.380 to 0.440.

4. A vehicular headlamp as claimed in claim 1, wherein said lighting circuit turns off said infrared light source, if speed of said vehicle is lower than a predetermined level.