Vehicular lamp

• US 9,423,095 B2
• Filed: 02/20/2014
• Issued: 08/23/2016
• Est. Priority Date: 02/22/2013
• Status: Active Grant

• Current Assignee: Koito Manufacturing Company Limited
• Original Assignee: Koito Manufacturing Company Limited
• Inventors: Yoshikawa, Kazushi, Suzuki, Tomokazu, Namba, Takanori, Tsuchiya, Toshiyuki, Watanabe, Masato
• Primary Examiner(s): May, Robert
• Assistant Examiner(s): Gyllstrom, Bryon T
• Application Number:
  US14/185,554
• Publication Number:
  US 20140241001A1
• Time in Patent Office: 915 Days
• Field of Search: 362/247, 362/373, 362/294
• US Class Current: 1/1
• CPC Class Codes: B60Q 1/0017 Devices integrating an element dedicated to another function
• CPC Class Codes: B60Q 11/00 Arrangement of monitoring devices for devices provided for in groups B60Q1/00 - B60Q9/00
• CPC Class Codes: B60Q 2300/054 Variable non-standard intensity, i.e. emission of various beam intensities different from standard intensities, e.g. continuous or stepped transitions of intensity
• CPC Class Codes: F21S 45/10 Protection of lighting devices cooling of lighting devices F21S45/40; waterproofing of lighting devices F21S45/50
• CPC Class Codes: F21S 45/40 Cooling of lighting devices
• CPC Class Codes: F21S 45/43 using gas
• CPC Class Codes: F21V 29/503 of light sources cooling arrangements structurally associated with gas-discharge or vapour-discharge lamps H01J61/52; cooling arrangements structurally associated with electric incandescent lamps H01K1/58; cooling arrangements structurally associated with light-emitting diodes H01L33/64
• CPC Class Codes: F21V 29/60 characterised by the use of a forced flow of gas, e.g. air
• CPC Class Codes: F21V 29/89 Metals

Abstract

A vehicular lamp includes a light source, a cooling fan configured to cool the light source, a light source power supply module configured to drive the light source for emission of light, and a control module configured to execute an abnormal rotation detection of the cooling fan and to control the light source power supply module so that the quantity of light emitted from the light source is reduced in response to a detection of abnormal rotation.

Claims

1. A vehicular lamp comprising:

a light source;

a cooling fan configured to cool the light source;

a light source power supply module configured to drive the light source for emission of light; and

a control module configured to execute an abnormal rotation detection of the cooling fan and to control the light source power supply module so that the quantity of light emitted from the light source is reduced in response to a detection of abnormal rotation,

wherein when detecting an abnormal rotation of the cooling fan, the control module controls the light source power supply module so that the quantity of light emitted from the light source module is reduced in accordance with a rotation speed of the cooling fan,

the control module changes a determination threshold which is used to detect an abnormal rotation of the cooling fan in accordance with information on a driving current which is supplied to the light source by the light source power supply module, and

when the driving current is low, the determination threshold is set to a lower value.

2. The vehicular lamp according to claim 1, wherein

when detecting an abnormal rotation of the cooling fan, the control module controls the light source power supply module so that the quantity of light emitted from the light source is reduced gradually.

3. The vehicular lamp according to claim 1, wherein

the control module performs the abnormal rotation detection based on a rotation speed signal from the cooling fan and generates a substitute rotation speed signal which indicates a normal rotation speed, and

when the input of the rotation speed signal is interrupted by a predetermined cause, the control module performs the abnormal rotation detection by using the substitute rotation speed signal as a substitute for the rotation speed signal from the cooling fan, preventing the interruption of the rotation speed signal from being detected as an abnormal rotation.

4. The vehicular lamp according to claim 1, wherein

the control module performs the abnormal rotation detection based on a rotation speed signal from the cooling fan,

the control module sets a predetermined period since activation of the cooling fan as a mask period during which the abnormal rotation detection based on the rotation speed signal is not performed, and

the control module determines that the abnormal rotation occurs in the cooling fan when a state corresponding to an abnormal rotation continues for a predetermined length of time in the rotation speed signal in other periods than the mask period.

5. The vehicular lamp according to claim 1, wherein

the control module changes a determination threshold which is used to detect an abnormal rotation of the cooling fan in accordance with temperature information.

6. The vehicular lamp according to claim 1, wherein the quantity of light emitted from the light source module is reduced at a degree at which a cooling capability of the cooling fan lowers.

7. The vehicular lamp according to claim 1, wherein the determination threshold is compared to a detected value of the rotation speed of the cooling fan.