Patent US5329206A successfully refreshed from Google Patents.
US5329206A
Expired / Lapsed
US
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Automatic headlamp dimmer having improved signal discrimination and signal processing
Assignee: Eaton Corp
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Filing: 1992-10-30
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Granted: 1994-07-12
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Expires: 2012-10-30
Abstract
Abstract An automatic headlamp dimmer system for switching a vehicle's headlamps from high beam to low beam when lights from another vehicle are detected in front of the vehicle. To prevent spurious responses to reflected light from signs and other sources, the dimmer system includes a light detector which is responsive only to infrared light. Also, unwanted responses to flashing lights are avoided by detecting the presence of a periodically varying light signal, and inhibiting switching between high and low beams in response thereto. The system is also capable of sensing the activation of windshield wipers and preventing headlamp switching caused by interruption of light to the system's light sensor by action of the wiper blades.
Inventors
- 👤 Kenneth G. Slotkowski
- 👤 Paul A. Michaels
- 👤 Harold R. Macks
- 👤 Henry J. Ewald
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 10:30
CPC Classifications
B; B60; B60S; B60S1/00; B60S1/02; B60S1/04; B60S1/06; B60S1/08; B60Q; B60Q1/00; B60Q1/02; B60Q1/04; B60Q1/14; B60Q1/1415; B60Q1/1423; H; H05; H05B; H05B47/00; H05B47/10; H05B47/105; H05B47/11; B60Q2300/00; B60Q2300/10; B60Q2300/14; B60Q2300/146; B60Q2300/30; B60Q2300/31; B60Q2300/312; B60Q2300/314; B60Q2300/40; B60Q2300/41; B60Q2300/42; B60Q2300/45; Y; Y02; Y02B; Y02B20/00; Y02B20/40
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
128 words
An automatic headlamp dimmer system for a vehicle having high and low beam headlamps including a light sensor for producing an electrical light signal in response to incoming light, an amplifier for amplifying said light signal, and a controller for transmitting a switch signal for causing said headlamps to switch between high beam and low beam modes, said controller comprising: means for detecting when the level of said light signal crosses a threshold; means for generating said switch signal a predetermined period of time after said light signal crosses said threshold; means for detecting periodicity in said light signal crossing said threshold; and means for blocking the generation of said switch signal when said periodicity is present, whereby said headlamps will not switch between high and low beams.
Claim 2
Dependent Claim
128 words
An automatic headlamp dimmer system for a vehicle having high and low beam headlamps including a light sensor for producing an electrical light signal in response to incoming light, an amplifier for amplifying said light signal, and a controller for transmitting a switch signal for causing said headlamps to switch between high beam and low beam modes, said controller comprising: means for detecting when the level of said light signal crosses a threshold; means for generating said switch signal a predetermined period of time after said light signal crosses said threshold; means for detecting periodicity in said light signal crossing said threshold; and means for blocking the generation of said switch signal when said periodicity is present, whereby said headlamps will not switch between high and low beams.
Claim 3
Dependent Claim
70 words
The system of claim 1 further comprising a hysteresis means for transmitting a signal to said amplifier which changes the gain of said amplifier depending on whether the headlights are in the high beam or low beam mode, wherein a different level of incoming light is necessary to cause said light signal to cross said threshold when said headlamps are in high beam than when in said low beam mode.
Claim 4
Dependent Claim
16 words
The system of claim 1 further comprising means for externally adjusting said threshold of said controller.
Claim 5
Dependent Claim
56 words
The system of claim 1 wherein said means for detecting periodicity further comprises: means for detecting light signals alternately and repetitively above and below said threshold; and means for detecting if said light signals above said threshold are approximately equal in duration and also if said light signals below said threshold are approximately equal in duration.
Claim 6
Dependent Claim
77 words
The system of claim 1 wherein said light sensor is mounted adjacent the windshield of the vehicle so that the field of view of the light sensor is through that portion of the windshield swept by the windshield wipers of the vehicle and further wherein said means for detecting periodicity further comprises windshield wiper detection means for determining if said periodicity is characteristic of interruptions in said light signal due to the operation of the windshield wipers.
Claim 7
Dependent Claim
64 words
The system of claim 5 wherein said windshield wiper detection means further comprises: means for detecting light signals alternately and repetitively above and below said threshold; means for detecting if said light signals below said threshold are approximately equal in duration; and means for detecting if the duration of one of said light signals above said threshold is less than a predefined time period.
Claim 8
Dependent Claim
20 words
The system of claim 1 wherein said light sensor is sensitive to infrared light and relatively insensitive to visible light.
Claim 9
Dependent Claim
23 words
The system of claim 7 wherein said light sensor comprises an infrared sensitive photodiode and an optical filter for substantially blocking visible light.
Claim 10
Dependent Claim
22 words
The system of claim 8 wherein said optical filter comprises a coating opaque to visible light that is applied to said photodiode.
Claim 11
Dependent Claim
94 words
An automatic headlamp dimmer system for a vehicle having high and low beam headlamps comprising: light sensor means for producing an electrical light signal in response to incoming light; amplifier means having associated therewith a gain, for amplifying said light signal; comparison means for producing an output signal when said amplified light signal crosses a threshold level; control means responsive to said output signal for controlling the energization of said high beam headlamps; and hysteresis means for varying the gain of said amplifier means in accordance with the state of said high beam headlamps.
Claim 12
Dependent Claim
94 words
An automatic headlamp dimmer system for a vehicle having high and low beam headlamps comprising: light sensor means for producing an electrical light signal in response to incoming light; amplifier means having associated therewith a gain, for amplifying said light signal; comparison means for producing an output signal when said amplified light signal crosses a threshold level; control means responsive to said output signal for controlling the energization of said high beam headlamps; and hysteresis means for varying the gain of said amplifier means in accordance with the state of said high beam headlamps.
Claim 13
Dependent Claim
42 words
The system according to claim 10 wherein said hysteresis means is adapted to increase the gain of said amplifier means when said high beam headlamps are off, and decrease the gain of said amplifier means when said high beam headlamps are on.
Claim 14
Dependent Claim
35 words
The system of claim 10 wherein said light sensor means is responsive to light in the infrared region of the light spectrum and substantially nonresponsive to light in the visible region of the light spectrum.
Claim 15
Dependent Claim
19 words
The system of claim 11 wherein said control means further includes sensitivity adjustment means for adjusting said threshold level.
Claim 16
Dependent Claim
23 words
The system of claim 13 wherein the same threshold level is used for controlling the energization and deenergization of said high beam headlamps.
Claim 17
Dependent Claim
65 words
The system of claim 14 wherein said sensitivity adjustment means and comparison means operate independently of said hysteresis means such that the ratio of the threshold intensity level of light impinging on said light sensor required to energize said high beam lamps relative to that required to deenergize said high beam lamps remains substantially constant regardless of adjustments to the level of said threshold level.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-07-11 | 1998-01-10 | 1998-07-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-07-11 | 2002-01-10 | 2002-07-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-07-11 | 2006-01-10 | 2006-07-12 | $7700.00 | Window Closed / Lapsed |