Headlight masking method and apparatus

• US 6,491,416 B1
• Filed: 05/25/2001
• Issued: 12/10/2002
• Est. Priority Date: 05/25/2001
• Status: Active Grant

• Current Assignee: Illume LLC
• Original Assignee: Illume LLC
• Inventors: Strazzanti, Michael
• Primary Examiner(s): O'Shea, Sandra
• Assistant Examiner(s): Alavi, Ali
• Application Number:
  US09/865,402
• Publication Number:
  US 20020186568A1
• Time in Patent Office: 564 Days
• Field of Search: 362/307, 362/311, 362/464, 362/465, 362/466, 362/267, 362/318, 362/512, 362/539, 362/467, 315/82, 315/83, 427/106, 427/165
• US Class Current: 362/464
• CPC Class Codes: B60Q 1/00 Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor for lighting vehicle interior B60Q3/00
• CPC Class Codes: B60Q 1/26 the devices being primarily intended to indicate the vehicle, or parts thereof, or to give signals, to other traffic
• CPC Class Codes: F21S 41/645 by electro-optic means, e.g. liquid crystal or electrochromic devices
• CPC Class Codes: F21V 3/04 characterised by materials, surface treatments or coatings
• CPC Class Codes: G02F 1/13347 working in reverse mode, i.e. clear in the off-state and scattering in the on-state

Abstract

A headlamp assembly having a headlamp bulb for emitting light and a bulb housing having a light transmissive portion for transmitting light from the headlamp bulb to an illumination zone. The housing is coated with a coating material which covers a selected region of the light transmissive portion of the housing. The coating material is electrically energized to alter an amount of light transmitted from the bulb to the illumination zone. A drive circuit electrically coupled to the coating material energizes the coating material to control a light output from the headlamp assembly.

Claims

1. A headlamp assembly comprising:

a headlamp bulb for emitting light from the headlamp assembly;

a bulb housing having a light transmissive portion for transmitting light from the headlamp bulb to an illumination zone, a portion of said housing coated with a coating material which covers a selected region of the light transmissive portion of the housing and which when electrically energized alters an amount of light transmitted from the bulb to the illumination zone; and

a drive circuit electrically coupled to the coating material for selectively energizing the coating material and thereby controlling a light output from the headlamp assembly.

2. The headlamp assembly of claim 1 wherein the coating comprises a sheet of pliable PDLC material that is affixed to the light transmissive portion of the housing.

3. The headlamp assembly of claim 1 wherein the light transmissive portion of the housing includes multiple bands of the coating material which can be independently energized to adjust the light output from the headlamp assembly.

4. The headlamp assembly of claim 3 wherein the headlamp assembly is adapted for mounting to a motor vehicle, and further wherein there are three bands of coating material applied to the light transmissive portion of the headlamp assembly and further wherein selectively controlling the opacity of the three bands produces a fog lamp output, a low beam output and a high beam output from the headlamp assembly.

5. The headlamp assembly of claim 3 wherein the driver circuit includes a user interface for monitoring multiple inputs that control the light transmissive state of the multiple bands.

6. The headlamp assembly of claim 5 wherein the driver circuit includes a programmable controller coupled to an output circuit that causes the bands to exhibit one of two light transmissive states, a relatively high light transmissive state and a relatively low light transmissive state.

7. The headlamp assembly of claim 3 additionally comprising additional regions of coating material that overlap one or more of the multiple bands of the coating material and wherein the drive circuit is electrically coupled to the additional regions to control a light transmissive state of said additional regions.

8. The headlamp assembly of claim 7 wherein both the additional regions and the bands exhibit one of two light transmissive states, a highly transmissive state and a low transmissive state and further wherein during intervals the drive circuit activates a selected band to render the selected band highly transmissive and further wherein any additional regions that overlap said selected band are activated to a low transmissive state.

9. The head lamp assembly of claim 1 wherein the drive circuit comprises:

a) a user interface including a switch selector;

b) a programmable controller for responding to the setting of the switch selector to produce a set of driver outputs; and

c) a driver circuit coupled to the coating material to apply an alternating signal to the coating material to alter the light transmissive characteristics of said coating material.

10. The head lamp assembly of claim 1 wherein the drive circuit includes a control output for adjusting a level of light transmission from the bulb through a region of said coating material at a high level of light transmission, a low level of light transmission, and at least one intermediate level of light transmission.

11. The head lamp assembly of claim 10 wherein the drive circuit includes a programmable controller that selectively controls a pulse width modulating signal output from the controller for adjusting the light transmission level of an associated region of said coating material.

12. A process for constructing a headlamp assembly comprising:

positioning a headlamp bulb that emits light within a headlamp housing having a light transmissive portion for transmitting light from the headlamp bulb to an illumination zone,

applying a coating material to the housing to cover selected regions of the light transmissive portion; and

coupling the coating material to a drive circuit for selectively energizing the coating material which when electrically energized renders a region of the light transmissive portion having the coating material more light transmissive to alter light transmitted from the bulb to the illumination zone.

13. The process of claim 12 wherein the coating material is coupled to the light transmissive portions in layers that are isolated from each other to allow independent energization of overlapping layers of said coating material.

14. The process of claim 12 wherein the coating material is organized in multiple bands across a surface of said light transmissive portion of the headlamp assembly which are coupled to the drive circuit independently to allow independent control over the light transmitting characteristics of said bands during operation of the headlamp assembly.

15. The method of claim 12 wherein there are multiple bands of coating material applied to the light transmissive portion of the headlamp assembly and the drive circuit is coupled to the multiple bands to independently control the light transmissive states of the bands to provide a fog lamp output, a low beam output and a high beam output from the headlamp assembly.

16. The method of claim 15 additionally comprising providing an user interface for monitoring multiple inputs that control the light transmissive state of the multiple bands.

17. The method of claim 15 additionally comprising additional regions of coating material that overlap one or more of the multiple bands of the coating material and wherein the drive circuit are coupled to the additional regions to independently control a light transmissive state of the additional regions.

18. The method of claim 12 wherein the energizing of the coating material adjusts a level of light transmission from the bulb through a region of said coating material to a high light transmission state, a low light transmission state, or one or more intermediate light transmission states.

19. The method of claim 12 wherein energizing of the coating material is performed by providing a pulse width modulating signal for adjusting a light transmission state of an associated region of said coating material.