(12) INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)
`
`(19) World Intellectual Property Organization
`International Bureau
`
`1111111111111111 IIIIII 111111111111111 IIIII 111111111111111 IIII IIIIIII IIII IIII IIII
`
`(43) International Publication Date
`27 September 2001 (27.09.2001)
`
`PCT
`
`(10) International Publication Number
`WO 01/70538 A2
`
`(51) International Patent Classification 7:
`
`B60Q
`
`40 Cheyenne, Holland, MI 49424 (US). POE, G., Bruce;
`3175 42nd Street, Hamilton, MI 49419 (US).
`
`(21) International Application Number: PCT/US0l/08912
`
`(22) International Filing Date: 20 March 2001 (20.03.2001)
`
`(25) Filing Language:
`
`(26) Publication Language:
`
`English
`
`English
`
`(30) Priority Data:
`09/528,389
`09/800,460
`
`20 March 2000 (20.03.2000) US
`5 March 2001 (05.03.2001) US
`
`(71) Applicant: GENTEX CORPORATION [US/US]; 600
`North Contennial Street, Zeeland, MI 49464 (US).
`
`(72) Inventors: STAM, Joseph, S.; 345 South Lakeshore
`Drive, Holland, MI 49424 (US). BECHTEL, Jon, H.; 136
`Sunrise Drive, Holland, MI 49423 (US). REESE, Spencer,
`D.; 1710 Columbia Avenue, Fort Wayne, IN 46805 (US).
`ROBERTS, John, K.; 1061 Plymouth Avenue, S.E., East
`Grand Rapids, MI 49506 (US). TONAR, William, L.;
`
`(74) Agent: CARRIER, Robert, J.; Price, Heneveld, Cooper,
`DeWitt & Litton, 695 Kenmoor, S.E., P.O. BOX 2567,
`Grand Rapids, Michigan 49501-2567 (US).
`
`(81) Designated States (national): AT, AU, BG, BR, CA, CH,
`CN, CZ, DE, DK, ES, FI, GB, GE, ffiJ, ID, IL, IN, JP, KR,
`MX, NO, NZ, PL, PT, RO, RU, SE, SG, SI, SK, TR, UA,
`YU,ZA.
`
`(84) Designated States (regional): European patent (AT, BE,
`CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC,
`NL, PT, SE, TR).
`
`Published:
`without international search report and to be republished
`upon receipt of that report
`
`For two-letter codes and other abbreviations, refer to the "Guid(cid:173)
`ance Notes on Codes and Abbreviations" appearing at the begin(cid:173)
`ning of each regular issue of the PCT Gazette.
`
`(54) Title: SYSTEM FOR CONTROLLING EXTERIOR VEHICLE LIGHTS
`
`== ---------------------------------------------
`
`1117
`
`1119
`
`1121
`
`1123
`
`1125
`
`400~
`
`1135
`
`COMPASS
`SENSOR
`
`IMAGE
`SENSOR
`
`-----201
`
`1137
`
`1006
`
`220
`
`1015
`
`SPEED INPUT
`-'---'------1101
`EC REVERSE
`\._ AMBIENT LIGHT
`OVERRIDE
`SENSOR
`AUTO ON/OFF
`SWITCH
`MANUAL
`DIMMER SWITCH
`VEHICLE BUS
`(OPTIONAL)
`
`GLARE LIGHT
`SENSOR
`
`EC MIRROR
`DRIVE
`
`11 09
`\._
`
`11
`\._
`
`EC
`ELEMENT
`
`1102
`
`1115
`
`MICROCONTROLLER
`
`\,_ 1105
`
`1127
`
`OUTPUTTO
`HEADLAMPS
`
`1/04~
`
`1141
`
`111
`
`0
`=
`~
`t-,.
`--... (57) Abstract: A system and method of automatically controlling exterior vehicle lights includes an image sensor (201) and a con-
`~ troller (1105) to generate control signals. The control signals are derived based on information obtained from the image sensor as
`well as other detected parameters pertaining to the detected light source(s), the vehicle having the inventive control system, and the
`0 ambient environment. The control circuit may simply turn certain exterior lights on or off, or change the brightness, aim, focus, etc.
`> to produce various beam patterns that maximize the illuminated area in front of the vehicle without causing excessive glare in the
`
`---iiiiiiiiiii
`
`iiiiiiiiiii
`
`- -- i
`
`iiiiiiiiii -iiiiiiiiiii
`iiiiiiiiiii -
`
`- 0
`
`;;-,- eyes of other drivers.
`
`VWGoA EX1007
`U.S. Patent No. 10,894,503
`
`

`

`WO 01/70538
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`PCT/US0l/08912
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`SYSTEM FOR CONTROLLING EXTERIOR VEHICLE LIGHTS
`
`BACKGROUND OF THE INVENTION
`
`The present invention pertains to control systems for controlling the exterior lights
`
`of a vehicle and components that can be used with such a control system.
`
`Modern automotive vehicles include a variety of different lamps to provide
`
`illumination under different operating conditions. Headlamps are typically controlled to
`
`alternately generate low beams and high beams. Low beams provide less illumination and
`
`are used at night to illuminate the forward path when other vehicles are present. High
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`beams output significantly more light and are used to illuminate the vehicle's forward path
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`when other vehicles are not present. Daytime running lights have also begun to
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`experience widespread acceptance. In addition, super bright high beams have been
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`proposed for use on fast rural roads. Foul weather lights, such as fog lights, are also
`
`commonly used. Other exterior vehicle lights include tail lights, brake lights center(cid:173)
`
`mounted stop lights (CHMSLs), turn signals, back-up lights, cargo lights, puddle lights,
`
`license plate illuminators, etc.
`
`Laws in various countries regulate vehicle illumination, and vehicle manufacturers
`
`must build cars that comply with these regulations. For example, regulations set forth by
`
`the United States Department of Transportation (DOT) regulate the light emissions of a
`
`vehicle's high beam headlamps. Various state regulations are used to control the amount
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`of glare experienced by drivers due to preceding vehicles ( other vehicles traveling in the
`
`same direction) and oncoming vehicles (vehicles traveling in the opposite direction).
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`Known vehicle high beam headlamp emissions in accordance with the DOT
`
`regulations limit the intensity to 40,000 cd at 0°, 10,000 cd at 3 °, 3250 cd at 6°, 1500 cd at
`
`9°, and 750 cd at 12°. An example of an emission pattern meeting this regulation is
`
`illustrated in Fig. 1 of U.S. Patent No. 5,837,994, entitled CONTROL SYSTEM TO
`
`AUTOMATICALLY DIM VEHICLE HEADLAMPS, issued to Joseph Scott Stam et al.
`
`on Nov. 17, 1998. In order to avoid an illuminance of 0.1 foot candles (fc) incident on
`
`another vehicle at these angles, the vehicle high beam headlamps should be dimmed
`
`within 7 00 feet of another vehicle if the vehicles are at an angle of 0°, within 3 5 0 feet of
`
`another vehicle if the vehicles are at a horizontal position of 3 °, and 200 feet of the other
`
`vehicle if the position of the other vehicle is at an angle of 6° to the longitudinal axis of the
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`controlled vehicle. It can thus be seen that a preceding vehicle directly in front of the
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`1
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`controlled vehicle (i.e., at an angle of 0°) will need to be identified well prior to the
`
`controlled vehicle catching up to the preceding vehicle, although the distance by which the
`controlled vehicle's headlamps must be dimmed for a preceding vehicle can be somewhat
`less than for an oncoming vehicle because glare :from behind is usually less disruptive than
`
`oncoming glare.
`
`In order to automatically control the vehicle headlamps, various headlamp dimmer
`control systems have been proposed. In order to prevent drivers of other vehicles :from
`
`being subjected to excessive glare levels, an automatic headlamp dimmer system must
`sense both the headlamps of oncoming vehicles as well as the tail lights of preceding
`
`vehicles. Some systems that effectively detect headlamps are unable to adequately detect
`
`tail lights. Most prior systems are unable to distinguish nuisance light sources, such as
`reflectors, street signs, streetlights, house lights, or the like, :from light sources that require
`
`headlamp control. Accordingly, these systems are subject to undesirable dimming of the
`
`high beams when no other traffic is present and turning on the high beams when other
`vehicles are present. In addition to the _undesirable performance, it is difficult for prior
`systems to comply with the legal requirements as described above for high beam control
`
`while avoiding unnecessary dimming of the vehicle headlamps.
`Fog lights are examples of other vehicle lights that are difficult to control
`automatically. Vehicles are known to include forward and rearward directed fog lights. In
`
`Europe, it is known to provide a very bright red or white light on the back of the vehicle,
`
`which is illuminated under foggy conditions. The fog lights must be turned ON as soon as
`the fog reduces visibility by a predetermined amount and must turn OFF when the fog
`drops below that density. A reliable method of automatically controlling such fog lights
`
`has not been available.
`Accordingly, there is a need for a more reliable and intelligent automatic lamp
`
`control for a vehicle.
`
`SUMMARY OF THE INVENTION
`
`According to one aspect of the present invention, a control system is provided to
`
`control exterior lights of a controlled vehicle. The control system comprises an imaging
`system configured to image the scene forward of the controlled vehicle, and a control
`circuit for processing the image of the scene obtained :from the imaging system and for
`
`controlling the exterior lights to change their beam pattern in response to objects detected
`
`2
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`in the processed scene, the control circuit disables automatic control of the exterior lights
`
`in response to activation of the vehicle windshield wipers.
`
`According to another aspect of the present invention, a control system is provided
`
`to control exterior lights of a controlled vehicle. The control system comprises an imaging
`
`system con.figured to image the scene forward of the controlled vehicle, and a control
`
`circuit for processing the image of the scene obtained from the imaging system and for
`
`controlling the exterior lights to change their beam pattern in response to objects detected
`
`in the processed scene, the control circuit disables automatic control of the exterior lights
`
`when the vehicle windshield defroster is operating at full speed.
`
`According to another aspect of the present invention, a control system is provided
`
`to control exterior lights of a controlled vehicle. The control system comprises an imaging
`
`system con.figured to image the scene forward of the controlled vehicle, and a control
`
`circuit for processing the image of the scene obtained from the imaging system and for
`
`controlling the exterior lights to change their beam pattern in response to objects detected
`
`in the processed scene, the control circuit disables automatic control of the exterior lights
`
`when snow is detected.
`
`According to yet another embodiment, a method of detecting snowfall or fog
`
`outside a vehicle is accomplished. The method comprises the steps of: sensing light levels
`
`forward above the vehicle; comparing the relative brightness of the light levels forward
`
`and above the vehicle; and determining that it is snowing or foggy when a ratio of the
`
`relative brightness forward of the vehicle to that above the vehicle reaches a threshold.
`
`According to another aspect of the present invention, a control system is provided
`
`to control the headlamps of a vehicle. The control system comprises an ambient light
`
`sensor for sensing the ambient light outside of the vehicle, and a control circuit for varying
`
`the beam pattern of daytime running lamps in response to the ambient light level sensed by
`
`the ambient light sensor.
`
`According to another aspect of the present invention, a control system is provided
`
`to control the brightness of the tail lights of a vehicle. The control system comprises an
`
`ambient light sensor for sensing the ambient light outside of the vehicle, and a control
`
`circuit for varying the brightness of the tail lights in response to the ambient light level
`
`sensed by the ambient light sensor.
`
`According to yet another aspect of the invention, a headlamp control system is
`
`provided for controlling the headlamps of a controlled vehicle that comprises: an imaging
`
`system con.figured to image the scene forward of the controlled vehicle; a control circuit
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`coupled to the imaging system for identifying and determining the brightness of light
`
`sources in images obtained from the imaging system and for controlling the headlamps to
`
`vary a beam pattern of the headlamps as a function of the brightness of light sources
`
`within the images; and a user input mechanism coupled to the control circuit for allowing
`
`a user to adjust a sensitivity at which the control circuit will control the headlamps in
`
`response to light sources within the images.
`
`According to yet another aspect of the invention, a headlamp control system is
`
`provided for controlling the headlamps of a controlled vehicle that comprises an imaging
`
`system configured to image the scene forward of the controlled vehicle and to detect an
`
`ambient light level outside the vehicle, and a control circuit coupled to the imaging system
`
`for determining an ambient light level outside the vehicle, for identifying and determining
`
`the brightness of light sources in images obtained from the imaging system, and for
`
`controlling the headlamps to vary a beam pattern of the headlamps as a function of the
`
`brightness of light sources within the images when the ambient light level is above a
`
`threshold level.
`
`According to another aspect of the present invention, a control system is provided
`
`to control exterior lights of a vehicle. The control system comprises an image array sensor
`
`including a plurality of pixels, an optical system configured to image the scene forward of
`
`the controlled vehicle onto the image array sensor, the optical system including a
`
`forwardmost surface, and a control circuit for processing the image of the scene obtained
`
`from the image array sensor and for controlling the exterior lights in response to objects
`
`detected in the processed scene, wherein the optical system includes a hydrophilic coating
`
`on the forwardmost surface.
`
`According to yet another aspect of the present invention, a vehicle control system
`
`is provided to control the brightness of continuously variable headlamps that have a
`
`brightness that varies continuously between a high beam state and a low beam state. The
`
`control system comprises an imaging system configured to image the scene forward of the
`
`controlled vehicle, a control circuit for identifying and determining the brightness of light
`
`sources in images obtained from the imaging system and for controlling the brightness of
`
`the headlamps as a function of the brightness of light sources within the images, and an
`
`indicator coupled to the control circuit and positioned inside the vehicle for indicating to
`
`the driver the relative brightness of the headlamps.
`
`According to another aspect of the invention, an imaging system for a vehicle is
`
`provided that comprises an image sensor having an array of pixels and at least one other
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`component, and an optical baffle disposed between the images sensor and a scene to be
`
`imaged for preventing light from the scene from reaching the at least one other
`
`component.
`
`According to a further aspect of the invention, a headlamp control system for a
`
`vehicle is provided that comprises an imaging system configured to image the scene
`
`forward of the controlled vehicle, a switching mechanism for manual input of a driver's
`
`selection of a feature affecting the control of the vehicle headlamps, and a control circuit
`
`coupled to the switching mechanism and the imaging system for identifying and
`
`determining the brightness of light sources in images obtained from the imaging system
`
`and for controlling the brightness of the headlamps as a function of the brightness of light
`
`sources within the images and as a function of the status of the switching mechanism.
`
`Another aspect of the present invention is to provide a headlamp control system for
`
`a vehicle that comprises a control circuit coupled to the vehicle headlamps for fading the
`
`headlamps of the vehicle to an off state in response to the turning off of the vehicle
`
`ignition or exiting the vehicle.
`
`According to another aspect of the invention, a control system is provided to
`
`control exterior lights of a vehicle. The control system comprises an image array sensor
`
`including a plurality of pixels, an optical system configured to image the scene forward of
`
`the controlled vehicle onto the image array sensor, the optical system including a
`
`forwardmost surface, and a control circuit for processing the image of the scene obtained
`
`from the image array sensor and for controlling the exterior lights in response to objects
`
`detected in the processed scene, the optical system includes a photocatalytic coating on the
`
`forwardmost surface.
`
`Another aspect of the present invention is to provide a control system to control the
`
`headlamps of a vehicle. The control system comprises a manually actuated switch
`
`mechanism for receiving input from a driver to temporarily increase the brightness of the
`
`vehicle headlamps in a flash-to-pass state, an ambient light sensor for sensing the ambient
`
`light outside the vehicle, and a control circuit coupled to the ambient light sensor and the
`
`manually actuated switch mechanism for varying the beam pattern of the headlamps
`
`during the flash-to-pass state in response to the ambient light level sensed by the ambient
`
`light sensor.
`
`According to yet another aspect of the present invention, a control system is
`
`provided to control the headlamps of a vehicle where the vehicle has a microwave receiver
`
`for receiving signals from satellites. The control system comprises a control circuit for
`5
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`receiving signals from the microwave receiver indicative of the location of the vehicle, the
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`control circuit controls the headlamps to limit the perceived brightness of the headlamps
`
`from exceeding a predetermined level less than their capacity when the vehicle is
`
`travelling on a residential street.
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`These and other features, advantages, and objects of the present invention will be
`
`further understood and appreciated by those skilled in the art by reference to the following
`
`specification, claims, and appended drawings.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`The subject matter that is regarded as the invention is particularly pointed out and
`
`distinctly claimed in the claim portion that concludes the specification. The invention,
`
`together with further objects and advantages thereof, may best be understood by reference
`
`to the following description taken in conjunction with the accompanying drawings, where
`
`like numerals represent like components, and in which:
`
`Fig. I illustrates vehicles traveling on a common road;
`
`Figs. 2a and 2b illustrate an optical sensor system, Fig. 2b showing a perspective
`
`view and Fig. 2a showing a cross section of the optical sensor system taken along plane
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`2a-2a in Fig. 2b;
`
`Fig. 3 is a plan view illustrating an image sensor used in the optical sensor system
`
`according to Figs. 2a and 2b;
`
`Fig. 4 is a top plan view illustrating a lens structure used in the optical sensor
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`system according to Figs. 2a and 2b;
`
`Fig. 5 is a side elevation view illustrating the lens structure according to Fig. 4;
`
`Fig. 6 is a graph illustrating wave transmissivity as a function of light wavelength
`
`for the lens;
`
`Fig. 7 shows a light sensitive surface of the image sensor and illustrates the regions
`
`of the image array which are impacted by the light from each of the lenses;
`
`Fig. 8 is a cross section illustrating another image sensor assembly taken along the
`
`same plane as the assembly in Fig. 2a;
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`Fig 9 is a cross section illustrating yet another light sensor assembly taken along
`
`the same plane as the assembly in Fig. 2a;
`
`Fig. IO is a partial cross section of a rearview mirror assembly illustrating an
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`optical sensor system;
`
`Fig. 11 is a circuit schematic illustrating a circuit for an optical sensor system and
`
`an electrochromic mirror;
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`6
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`Fig. 12 is a circuit schematic illustrating a headlamp drive for the circuit according
`
`to Fig. 11;
`
`Fig. 13 is a circuit schematic illustrating a microcontroller circuit for the circuit
`
`according to Fig. 11;
`
`Fig. 14 is a flow chart illustrating operation of an electrochromic mirror and
`
`headlamp control;
`
`Fig. 15 is a flow chart illustrating operations to acquire and analyze an image;
`
`Fig. 16 is a flow chart illustrating operations to analyze an image and find a light
`
`source;
`
`Fig. 17a is a flow chart illustrating a seed fill algorithm;
`
`Fig. 17b illustrates a pixel array impacted by a light source;
`
`Fig. 18 is a flow chart illustrating operation to determine if light sources are
`
`oncoming or preceding vehicles;
`
`Fig. 19 is a state diagram illustrating the duty cycle associated with states for a
`
`variable high beam lamp;
`
`Fig. 20 illustrates operation rules for changes of state in Fig. 19;
`
`Fig. 21 is a flow chart illustrating operation to provide speed varying thresholds;
`
`Fig. 22 is a chart illustrating the different regions of the image array;
`
`Fig. 23 is a flow chart illustrating operation of the microcontroller to shift the
`
`regions in Fig. 22;
`
`Fig. 24 is a front perspective view illustrating an image sensor assembly including
`
`an electronically alterable filter;
`
`Fig. 25 is a side elevation view of the liquid crystal filter in the image sensor
`
`assembly according to Fig. 24;
`
`Fig. 26a is an exploded perspective view illustrating an LED headlamp;
`
`Fig. 26b is a fragmentary cross section taken along plane 26b-26b in Fig. 26a;
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`Fig. 26c is a front plan view illustrating an alternate embodiment of an LED lamp;
`
`Fig. 26d is a fragmentary cross section taken along plane 26d-26d in Fig. 26c;
`
`Fig. 27 is a top, front perspective view of an LED headlamp for projecting light in
`
`more than one horizontal direction;
`
`Fig. 28 is a top, front perspective view of an LED headlamp for projecting light in
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`more than one vertical direction;
`
`Figs. 29a-29d illustrates a method of manufacturing surface mounted filters for an
`
`image sensor;
`
`7
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`Fig. 30 is a chart illustrating the wavelengths passed by a red filter surface mounted
`
`to an image sensor;
`
`Fig. 31 is a chart illustrating the wavelengths passed by a cyan filter surface
`
`mounted to an image sensor;
`
`Fig. 32 illustrates another image sensor assembly;
`
`Fig. 33 illustrates an electrical system including a wave sensitive headlamp
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`control;
`
`Fig. 34 is a circuit schematic illustrating an alternative circuit for an optical sensor
`
`system and an electrochromic mirror;
`
`Fig. 35 is a state diagram illustrating a first control scheme for manually or
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`automatically controlling the vehicle headlamps in response to activation of various
`
`manual switches;
`
`Fig. 36 is a state diagram illustrating a second control scheme for manually or
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`automatically controlling the vehicle headlamps in response to activation of various
`
`manual switches;
`
`Fig. 37 is a state diagram illustrating a third control scheme for manually or
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`automatically controlling the vehicle headlamps in response to activation of various
`
`manual switches;
`
`Fig. 3 8 illustrates an exemplary indicator for use with the headlamp control system
`
`of the present invention;
`
`Fig. 39 is a representative pictorial view of an imaged scene taken in several
`
`superimposed frames;
`
`Fig. 40 is a functional block diagram of one embodiment of the present invention;
`
`Fig. 41 is front elevational view of a mirror mount accessory housing according to
`
`another embodiment of the present invention;
`
`Fig. 42 is top plan view of the mirror mount accessory housing shown in Fig. 41;
`
`Fig. 43 is a cross-sectional view of the mirror mount accessory housing shown in
`
`Figs. 41 and 42 taken along line 43-43' in Fig. 42;
`
`Fig. 44 is an exploded perspective view of the mirror mount accessory housing;
`
`Fig. 45 is rear elevational view of the mirror mount accessory housing;
`
`Fig. 46 is a side elevational view of the mirror mount accessory housing with the
`
`housing cover removed;
`
`Fig. 4 7 is a top plan view of the mirror mount accessory housing with the housing
`
`cover removed;
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`8
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`Fig. 48 is a front elevational view of the mirror mount accessory housing with the
`
`housing cover removed;
`
`Fig. 49 is a rear elevational view of the mirror mount accessory housing with the
`
`housing cover removed; and
`
`Figs. 50A-50C are pictorial representations of various illumination patterns
`
`produced by exterior lights of a vehicle.
`
`DETAILED DESCRIPTION OF THE INVENTION
`
`The present invention generally pertains to a control system for controlling the
`
`exterior lights of a vehicle. As noted above, such exterior lights may include headlamps,
`
`tail lights, foul weather lights such as fog lights, brake lights, center-mounted stop lights
`
`(CHMSLs), turn signals, back-up lights, cargo lights, puddle lights, license plate
`
`illuminators, etc. The headlamps may be operated in several different modes including
`
`conventional low-beam and high-beam states. They may also be operated as daytime
`
`running lights, and additionally as super-bright high beams in those countries where they
`
`are permitted. The headlamp brightness may also be continuously varied between the low,
`
`high, and super-high states. Separate lights may be provided for obtaining each of these
`
`headlamp states or the actual brightness of the headlamps may be varied to provide these
`
`different headlamp states. In either case, the "perceived brightness" of the headlamps is
`
`varied. As used herein, the term "perceived brightness" means the brightness of the
`
`headlamps as perceived by an observer outside the vehicle. Most typically, such observers
`
`will be drivers or passengers in a preceding vehicle or in a vehicle traveling along the
`
`same street in the opposite direction. Ideally, the exterior lights are controlled such that if
`an observer is located in a vehicle within a "glare area" relative to the vehicle (i.e., the
`
`area in which the observer would perceive the brightness of the exterior lights as causing
`
`excessive glare), the beam illumination pattern is varied such that the observer is no longer
`
`in the glare area. The perceived brightness and/or glare area of the headlamps (and/or
`
`other exterior lights) may be varied by changing the illumination output of one or more
`lights forming the headlamps, by steering one or more lights to change the aim of one or
`
`more of the lights forming the headlamps, activating or deactivating some or all of the
`
`lights, altering the illumination pattern forward of the vehicle, or a combination of the
`
`above. Fig. 50A shows a typical low beam pattern as would be used when other vehicles
`are nearby and forward of the controlled vehicle 5000. Fig. SOB shows an examplary
`composite beam pattern including both high and low beam patterns and side bending light
`
`patterns, which may be individually activated as the vehicle 5000 approaches a turn. Fig.
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`SOC illustrates another composite beam pattern including a low beam pattern and an
`
`intermediate, side-aimed pattern, which may be produced by changing the focus or aim of
`
`the high beams as well as the brightness of the high beams. The composite beam pattern
`
`shown in Fig. SOC is useful when another vehicle is approaching in an oncoming and
`
`adjacent lane. As will be apparent to those skilled in the art, a large number of other beam
`
`patterns can be achieved using known headlamp mechanisms. Other mechanisms for
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`adjusting the perceived brightness and glare area of the headlamps will also be apparent to
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`those skilled in the art.
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`Although the present invention primarily addresses the control of the vehicle
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`headlamps, embodiments are described below for controlling the tail lights and foul
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`weather lights. In some embodiments, the present invention is generally described as
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`controlling the "exterior lights," which broadly includes any exterior lighting on the
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`vehicle. For example, the present invention may be used in some circumstances to control
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`the perceived brightness of a turn signal mounted in an outside rearview mirror assembly
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`so as to provide sufficient light output for signaling a driver in another vehicle without
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`causing excessive glare in the eyes of the driver of the vehicle having the signal mirrors.
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`Also, the present invention may be employed to control the instrument panel lights as well
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`as other interior display lights based upon the sensed ambient light. Other examples will
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`be apparent to those skilled in the art.
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`A controlled vehicle 100 (Fig. 1) having an automatic headlamp dimmer includes
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`an optical sensor system 102 for detecting the headlamps 104 of an oncoming vehicle 105
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`and the tail lights 108 of a preceding vehicle 110. The headlamps 111 of the controlled
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`vehicle 100 are controlled automatically to avoid shining the high beams, or bright lights,
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`directly into the eyes of a driver of oncoming vehicle 105 or by reflection into the eyes of
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`the driver of the preceding vehicle 110. The optical sensor assembly 102 is illustrated
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`mounted in the windshield area of the vehicle, but those skilled in the art will recognize
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`that the sensor could be mounted at other locations that provide the sensor with a view of
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`the scene in front of the vehicle. One particularly advantageous mounting location is high
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`on the vehicle windshield to provide a clear view, which view can be achieved by
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`mounting the optical sensor assembly 102 in a rearview mirror mount, a vehicle headliner,
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`a visor, or in an overhead console. Other views that may be advantageously employed
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`include mounting the optical sensor assembly· 102 on the A-pilar, the dashboard, or at any
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`other location providing a forward viewing area. However, the most advantageous
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`mounting locations are those that position the image sensor to view a forward scene
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`through an area kept clean by the vehicle's windshield wipers.
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`With reference to Figs. 2a and 2b, the optical sensor assembly 102 includes an
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`electronic image sensor 201 and an optical system to direct light onto the image sensor
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`201. The image sensor 201 generally comprises an array of light sensitive components
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`and associated circuitry to output electronic pixel light level signals responsive to light
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`impacting on the surface of the image sensor 201. The optical system generally contains
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`four components: lens structure 202; aperture stop member 203; far field baffle 204; and
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`optional infrared filter 206. The optical system controls the scene viewed by the image
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`sensor 201. In particular, the optical system focuses light rays 205 passing through
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`opening 207 of the far field baffle onto the array 201 contained within the image sensor
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`assembly 201.
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`THE IMAGE SENSOR
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`The configuration of the image sensor 201 is illustrated in Fig. 3. The image
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`sensor includes an image array 301 (Fig. 3) that can be made from any one of a variety of
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`sensors, such as CMOS image sensors, charge coupled device (CCD) image sensors, or
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`any other suitable image sensor. In one embodiment, the image sensor is a CMOS
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`photogate active pixel image sensor. A CMOS photogate active pixel image sensor is
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`described in U.S. Patent No. 5,471,515, entitled ACTIVE PIXEL SENSOR WITH
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`INTER-PIXEL CHARGE TRANSFER, issued to Eric R. Fossum et al., on November 28,
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`1995. Sensor systems including arrays are disclosed in U.S. Patent Application No.
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`09/448,364, entitled CONTROL CIRCUIT FOR IMAGE SENSORS, filed November 23,
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`1999, by Jon Bechtel et al.; U.S. Patent Application No. 08/933,210, entitled CONTROL
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`CIRCUIT FOR IMAGE SENSORS, filed on September 16, 1997, by Jon Bechtel et al.,
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`now U.S. Patent No. 5,990,469; and U.S. Patent Application No. 08/831,232, filed April 2,
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`1997, entitled CONTROL SYSTEM TO AUTOMATICALLY DIM VEIDCLE
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`HEADLAMPS, by Joseph Stam et al., now U.S. Patent No. 5,837,994.
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`The array 301 may for example comprise photogate active pixels, such as 10 to 50
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`µm pixels. It is advantageous for the array to be a low resolution array, which is an array
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`that has a resolution of less than 7000 pixels per square millimeter and more preferably
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`less than 2500 pixels per square millimeter. The array may have 25µm or larger photogate
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`active pixels. In particular, the array may include 30 µm or larger pixels arranged in a grid
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`smaller than 200 rows by 200 columns, and may advantageously comprise a rectangular
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`array having 64 columns and 80 rows of pixels. Such an image sensor is described in
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`detail in U.S. Patent No. 5,471,515. The optically active region of array 301 is
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`approximately 1.9 mm in the X direction by 2.4 111111 in the Y direction. Using such a low
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`resolution image sensor array to monitor the forward field of the controlled vehicle 100
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`results in a relati