asy United States
`a2) Patent Application Publication co) Pub. No.: US 2002/0196639 Al
`
` Weidel (43) Pub. Date: Dec. 26, 2002
`
`
`US 20020196639A1
`
`(54) VEHICLE HEADLIGHT
`(76)
`Inventor: Edgar Weidel, Hudlerstrasse (DE)
`
`(52) US. Chcece 362/521; 362/268; 362/545;
`362/331
`‘
`
`Correspondence Address:
`Stephen A. Pendorf
`Pendorf & Cutliff
`P.O. Box 20445
`Tampa, FL 33622-0445 (US)
`
`(21) Appl. No.:
`
`10/176,181
`
`(22) Tiled:
`
`Jun. 20, 2002
`
`(30)
`
`Foreign Application Priority Data
`
`(DE)eee 10129743.2-33
`Jun. 20, 2001
`Publication Classification
`
`(57)
`
`ABSTRACT
`
`The invention concerns a vehicle headlight, comprising a
`two-dimensional array(2) ofa plurality of electronic light
`emitter elements (4), which are arranged lor emitting a
`plurality of parallel light beams (6), a collection lens (8),
`which is provided one focal lengih awayessentiallyparallel
`to the two-dimensional array and positioncd for recciving
`the light emitted by the array, and a control electronic for the
`light cmittcr clements operatively associated for cncrgizing
`the light emitter elements (4) individually or in groups. This
`results in a headlight with variable light emission charac-
`teristics, which is mechanically particularly simple to con-
`struct, is operationally reliable, and is rapid to react.
`
`(51)
`
`Inte C17 i ccnsesssnsessntntntntcecee F21V 5/00
`
`
`
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`Patent Application Publication Dec. 26, 2002 Sheet 1 of 2
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`US 2002/0196639 Al
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`UNIFIED PATENTS EXHIBIT 1005
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`Patent Application Publication Dec. 26,2002 Sheet 2 of 2
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`US 2002/0196639 Al
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`US 2002/0196639 Al
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`Dec. 26, 2002
`
`VEHICLE HEADLIGHT
`
`BACKGROUND OF THE INVENTION
`
`1. Field of the Invention
`[0001]
`[0002] The invention concerns a vehicle headlight.
`
`2. Description of the Related Art
`
`[0003]
`Poor visibility at night is a stressful and dangerous
`[0004]
`situation, and is feared by manydrivers. The occurrence of
`accidents is significantly higher under poor visibility con-
`ditions than in the case of vehicle operation by day under
`good visibility conditions. In particular at night, the follow-
`ing difliculuies occur:
`
`[0005] The range of view with dim or normal head-
`lights is minimal whenthere is oncomingtraffic, and
`is erroneously estimated by manyvehicle operators.
`The leads to a late recognition of non-illuminated
`obstacles, pedestrians, bicycles without lights and of
`animals, and therewith leads to accidents.
`
`[0006] The vehicle operator is blinded for a short
`time by the headlights of oncoming vehicles, and
`their reflection particularly in the case of wet road
`surfaces the vehicle operator is driving for a short
`period of time into a black hole. Particularly endan-
`gered are those with poor night vision and older
`vehicle operators due to their reduced vision capac-
`ily.
`
`In the case of rain, fog and snowdrifts the
`[0007]
`range of vision can again be substantially reduced.
`
`In order to optimally illuminate the traffic scene at
`[0008]
`night, vehicle headlights are known, of which the illumina-
`tion characteristics can be adapted to the course of the road.
`These headlights can be motorized for tilting in the vertical
`direction, in order to compensate for differences in vehicle
`loads or crests or dips in the road ahead of the vehicle, or
`may be pivoted in the horizontal direction,
`in order to
`compensate for curves. The mechanism necessarytherefore
`is frequently expensive andliable to fail, and as an alterna-
`tive there remains only the possibility of providing different
`types of headlights, and switching between them. This type
`of headlight can also be employed in order to produce
`desired breadth, or lowering of illumination in the case of
`fog or whenit is snowing. Tor design and cost reasonsit is
`however frequently not desired to equip a vehicle with a
`large numberof headlights.
`
`
`
`[0009] A further improvementof the view al night can be
`achieved by an opto-electronic system, as disclosed for
`example in DE 40 07 646 Al. The system records a video
`image of a traffic scene and represents this to the vehicle
`operator in suitable form, The represented image contains
`supplemental information, which the vehicle operator can-
`not see with his own eyes or can only recognize with
`difficulty, in particular at night, poor weather and fog.
`[0010]
`In addition to the normal headlights this system
`supplementally contains infrared headlights, which utilize
`near infrared emitting laser diodesas light sources. The laser
`diodes are driven pulsed. A CCTD-camera is incorporated in
`the roof area of the vehicle for recording the video image.
`The CCD-camera has an electronic lock, which is synchro-
`nized with the laser diodes. An optical band passfilter is
`
`introduced prior to the camera lens. The video image is
`shown to the vehicle operator on a LCD-display. The
`employmentof laser lights has a number of advantages:
`[0011] The lasers emit in the near infrared at a wavelength
`of 810 nm. Since the infrared light is nearly invisible to the
`humaneye, illumination can beleft turned on continuously.
`
`[0012] By use of laser lights it becomes possible to
`substantially reduce the blinding of the camera bythe visible
`headlights of oncoming vehicles. On the one handthe laser
`light is emitted at a spectral breadth of only a few nm, while
`visible light sources such as halogen lights cover several
`hundred nm. If one applics an optical filter with a narrow
`transmissivity breadth in front of the camera lens,
`then
`almost the entire laser light is transmitted while the light of
`oncoming vehicles is reduced by a factor of 50 to 100. On
`the othcr hand, the laser diodes preciscly follow the drive
`current, it can thus be rapidly pulsed in a simple manner.If
`one employs a video camera with a rapid electronic shutter,
`which is synchronized with the lasers,
`then the light of
`oncoming vehicles can be further reduced.
`
`In the above mentioned publication it is further
`[0013]
`proposed that
`the intensity of the illumination is varied
`depending upon the emission angle, for example in order to
`illuminate the foreground ofa traffic scene with less inten-
`sity than the background. Therewith the surface illumination
`by the laser light, which decreases with increasing distance,
`can be compensated and a more even illumination of the
`scene can be achicved. More specifically, a laser beam is
`pivoted back and forth in one spatial direction, and in a
`direction perpendicular thereto is either evenly distributed or
`
`is likewise rapidly pivoted, in order to sequentially sample
`
`
`the traffic scene, and the intensity of the laser light is varied
`in synchrony with the movement of the pivoting mirror.
`There arc however significant technological requircments
`for the mechanics of the pivoting of the mirror, which in the
`case of a vehicle are not easily accomplished. The reaction
`times maybeshorter than with a purely mechanical pivoting
`of conventional headlights, but they do remain limited.
`
`
`
`SUMMARY OF THE INVENTION
`
`[0014] The invention is concerned with the task of pro-
`viding a headlight with variable iumination characteristics,
`which can be mechanically constructed particularly simply,
`operates reliably and, besides this, reacts rapidly.
`
`[0015] This task is solved by a vehicle headlight with a
`two-dimensional array comprising a plurality of electronic
`lighting elements, which are arranged to emit a plurality of
`light beams parallel to each other; a collection lens, which
`is arranged approximately its focal length away essentially
`parallel to the surface of the array, in order to reccive the
`light from the array; and a control electronic for the illumi-
`nation elements, which is set up to allowthe light elements
`to selectively illuminate or emit individually or group-wise.
`
`In accordance with the invention the illumination
`[0016]
`characteristic of the headlight can be adapted to different
`traffic or environmental considerations solely with the aid of
`the control electronic. No moveable mechanical parts are
`necessary, only one headlight lens is necessary.
`[0017] The invention can be employed in a night illumi-
`nation system, as described in previously mentioned DE 40
`07 646 A1, preferably in that the headlight is provided with
`
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`US 2002/0196639 Al
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`Dec. 26, 2002
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`
`
`a oumberof electronic light elements, which are provided to
`emit a plurality of light beamsparallel to each other, wherein
`
`
`each array of
`emitted light has a wavelength which is
`
`
`different from those of the one or more other arrays, and
`wherein the multiple arrays are so arranged,
`that
`their
`
`respective light beams meet in a beam combiner(the reverse
`
`of a beam diffuser or distributor), which directs the light
`beamsof all arrays in parallel to a commoncollection lens,
`as well as a control electronic for the light elements, which
`is designed to selectively allow individual or group oflight
`elements to illuminate.
`
`In this mannerit is possible to produce for example
`[0023]
`an array of infrared light, and the remaining arrays can
`produce visible light. Alternatively or additionally two or
`more arrays can emit visible monochromiclight with respec-
`tive different wavelengths, which together produce white
`light. In both cases all that is needed is one collectionlens,
`for whichreasonthe size of the headlight can be made small.
`
`BRIEF DESCRIPTION OF TITE DRAWINGS
`
`the
`[0024] Further characteristics and advantages of
`invention can be seen from the dependent claims and the
`following description of embodiments on the basis of the
`figures. In the figures there is shown:
`
`[0025] FIG. 1 aside viewof a vehicle headlight with light
`elementarray,
`
`[0026] FIG. 2 a view ofthe vehicle headlight from above,
`and
`
`[0027] FIG.3 an embodimentfor a vehicle headlight with
`multiple light clement arrays.
`
`DETAILED DESCRIPTION OF THE
`INVENTION
`
`LEDsorlaser diodes, which emit in the near infrared range.
`The invention can however also be used as vehicle head-
`lights for visible light, preferably in that the headlight is
`provided with white light LEDs or laser diodes, Such a
`vehicle headlight can, depending upon the control or driving
`of the light elements, produce high beams or low beamsas
`well a large number of further illumination characteristics.
`Also possible is a combined application of the headlight
`with variable illumination characteristics both for visible as
`
`
`well as for non-visible, in that the headlight is provided with
`
`light elements of differing emissions.
`[0018] he light beams of the individual light elements
`have, after they pass throughthe collection lens, a particular
`divergence which ts actually desirable in the application as
`a vehicle headlight, on the basis of which they overlap with
`each other after a certain distance. In the case that the design
`is such that the divergence is so small, that close objects
`would appear to exhibit an undesired striped pattern, a
`diffuser can be provided, which appropriately spreads the
`light beams. The diffuser is preferably provided close to the
`collection lens on its emission side or is integrated in the
`collection lens (which may also be a convergent, divergent,
`or condenserlens).
`[0019]
`In a preferred embodiment the control electronic
`selects receives data regarding the traffic situation or envi-
`ronmental conditions from sensors and based thereon selects
`those light elements which are allowed to illuminate. Appro-
`priale sensors would include,
`for example,
`those which
`measure the spring compression of the individual wheels,
`road curve sensors, sensors for visibilily, weather and street
`lighting relationships and the vehicle environment as well as
`manyothers. Since the invention can be carried out without
`moveable mechanical components,
`the adaptation to the
`detected traffic or environmental conditions can occur rap-
`idly, so that these can be compensated for, even if they
`change rapidly over time.
`[0028] The light source can beaflat array of laser diodes
`preferably surfacing emitting lasers, so-called VCSELs—or
`[0020] The individual light elements can be activated or,
`an array oftightly or densely packed individual LEDs; both
`as the case may be, deactivated by a simple switching on and
`types are collectively referred to in the following with the
`off, wherein intermediate intensities can be selected in that
`term diode array.
`for example every second light element is activated. Inter-
`mediate intensities can however also be achieved thereby,
`that the control electronic supplies someorall light elements
`with a lower drive current than the set current. In special
`cases, for example when sensorsin the vehicle, during poor
`environmental illumination condilions, register an extraor-
`dinary danger situation, the control electronics can lumi-
`nate the light elements or even only those which dluminate
`a particular sector in which the danger situation is registered,
`and supply these even with a excess of current, in order to
`better highlight the situation for the vehicle operator, with-
`out
`the life expectancy of the light elements suffering
`significantly thereby.
`
`In the preferred embodiment the inventive vehicle
`[0021]
`headlightis a front headlight. It is however conceivable that
`it forms for example a combination of backup light, brake
`light and fog light, whercin in normal vehicle opcration at
`night only individual light clements arc activated, further
`light elements are activated during braking whereby certain
`special provided light clements in certain cases provide the
`illumination characteristic of a fog light.
`
`the vehicle headlight
`In another embodiment
`[0022]
`includes two dimensional arrays, which respectively include
`
`[0029] The diode array 2 in the illustrated embodimentis
`a quadrilateral arrangement in the two dimensional plane of
`n diodes 4 in the vertical direction (FIG. 1) and m diodes 4
`in horizontal direction (FIG. 2). That means, overall a total
`of nxm diodes 4 are provided in the rectangular field with n
`rows and m columns. The arrangement however need not be
`quadrilateral, but rather can be for example alsoelliptical or
`scmi-clliptical, depending upon which area of ahead of the
`vehicle in which the headlight is incorporated is to be
`illuminated.
`
`‘The diodes 4 are supplied with current by a not
`[0030]
`shown control circuit, which makesit possible to selectively
`allow the diodes 4 to illuminate with desired intensity, either
`individually or in predetermined groups.
`
`[0031] The diode array 2 is connected or associated with
`a not shown cooling body at the backside of the headlight.
`Thelight of each individual diode 4 broadens with an angle
`a. of for example 10° both vertically as well as horizontally.
`The light beams emitted by the individual diodes 4 are
`shown with dotted lines in FIGS. 1 and 2. For ease of
`illustration in FIG. 1 only beams of two diodes 4 and in
`FIG.2 only one diode 4 emission is indicated orillustrated;
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`US 2002/0196639 Al
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`further only the central beam and the edge beamof the light
`beam 6 emitted by the individual diodes 4 is shown.
`
`[0032] The diode array 2 is introduced to the focal point of
`a collection lens 8. For purposes of explanation the diode
`array 2 and the collection lens 8 arc illustrated in such close
`proximity that the angle @ in the figures appears substan-
`tially larger than it would normally.
`
`[0033] The collection lens § can be a simple lens, a planar
`convex lens, a Fresnel
`lens or an aspherical
`lens. The
`collection lens 8 collumates the diverging light beams 6 of
`each diode 4. Aller emission from the collection lens 8 the
`light beams 6 exhibit a not shown divergence 6, which
`depends upon the size of the light emission surface of one
`individual diode 4, uponrefraction and upon the shape of the
`collection lens 8.
`
`
`
`
`
`In the vertical direction (FIG. DL) this divergence 6
`[0034]
`
`is expanded by a diffuser 10 to a divergence of 81. The 81
`should be solarge, that the light beams 6 of adjacent diodes
`4 overlap, and such that upon suitable electronic control the
`diodes 4 produce the desired angulardistribution of the light
`beams 6. The maximal emitable vertical angle range or area
`is shown in FIG. 1 by 26 and can be calculated by the
`distance of the outer-lying diodes 4 divided bythe focal
`width f of the collection lens 8.
`
`in accordance with
`In the horizontal direction,
`[0035]
`FIG.2, a divergence 62 dillering from $1 can be produced,
`namely by appropriate arrangementof the diffuser 10 and/or
`on the basis of a non-spherical-symmetrical emission char-
`acteristic of the diodes 4.
`
`[0036] As diffuser 10 one can employ either a holographic
`
`diffuser or a diffuser with micro-lenses or micro-wedges.
`
`
`
`The diffuser 10 can work on the basis of refraction or
`diffraction. In a further, not shown, manner of construction,
`the diffuser 10 can be integrated in the collection lens 8.
`
`[0037] The diffuser 10 produces the desired headlight
`distribution from the incident culminated light beams6. In
`the case that the divergence 6 of the light beam 6 emitted
`from the collection lens 8 is large enough, then the diffuser
`10 can be dispensed with.
`
`[0038] The angular distribution of the light emitted by the
`headlight can now be changed and adapted over a broad area
`quite rapidly, and namely by electronic controlof individual
`diodes 4 or groups of diodes 4. Examples of such a selective
`control in the the vertical or as the case maybe horizontal
`direction is described in the following.
`
`[0039] A) In the vertical direction
`[0040]
`1) If all diode lines are energized, one obtains
`simultaneously high beams and dimmed beams.
`
`2) If only the diode lines n/2 through n(that is the
`[0041]
`lower half of the diodes 4 in FIG. 1) are energized, one
`obtains dimlight.
`
`3) In gencral, the vertical light distribution can be
`[0042]
`controlled, varicd and optimized by the intensity of the
`current with which the individual diode lines are energized.
`
`4) A tilting of the vehicle by heavy loading or
`[0043]
`tilting during operation in the course of unevenness of the
`roadway can be compensated by measuring the spring
`compression of the individual wheels and, with a control
`
`signal derived therefrom for the drive current of the diode
`lines, be dynamically compensated. This control can be so
`rapid that no change in the illumination can be percieved
`even in the course of strong unevenness. Therewith an even,
`optimal illumination of the roadway can be accomplished.
`
`[0044]
`
`8B) In the horizontal direction
`
`In analogous manner it becomes possible in the
`[0045]
`horizontal direction by control of appropriate groups of
`diodes 4 to adjust and optimize the horizontal light distri-
`bution. The distribution can be selected to be broader or
`narrower, and the maximum can be pivoted towards one
`side, in order to illuminate into curves. Also these variations
`are accomplished by changing the current to the diodes.
`
`[0046] FIG. 3 shows a vehicle headlight, which contains
`two dimensional diodes arrays 12, 12' which respectively
`contain a plurality of light diodes 14, 14. The diodes 14, 14
`emit in operation respectively one set of light beams 16, 16
`parallel to each other, from which in FIG. 3 respectively
`onlythe central beam is illustrated. The diode arrays 12, 12'
`are oriented perpendicular to each other, so that thei light
`beams 16, 16' impinge in a beam divider 20 which directthe
`light beams 16, 16' of the two diode arrays 12, 12' parallel
`to a common collection lens 18. That means,
`the beam
`distributor 20 is used here as a beam combiner. Further, a
`here not shown diffuser can be employed as in FIG. 1.
`
`[0047] As an example, the light beams 16are visible light
`with a particular wavelength 4, and the light beams 16' are
`
`
`visible light with a particular wavelength 2, which is
`
`
`different from 4,, wherein A, and A, lie on the normal color
`table on a plane through the color spectrum center (ie.,
`thorough the center non-colored point, resulting in a full
`addition). Thereby the light united by the beamdistributor
`20 appears to the human eye as white light, and one can
`produce a white light headlight with employment of mono-
`chromic light diodes and with only one collection lens 18,
`which is the element which normally occupies the most
`substantial part of the headlight space.
`
`[0048] Alternatively one of the wavelengths 4, and 4, can
`lie in the infrared range, so that with only one collection lens
`18 a combined infrared and visible light headlight is pro-
`duced.
`
`If one in this case would also like to use for the
`[0049]
`vehicle headlight monochromic light diodes, one requires at
`least one further diode array, which in FIG.3 is not shown,
`and a beam distributor, which units the light of all diode
`arrays.
`
`Inthe example from FIG. 3 the beam distributor 20
`[0050]
`includes a dielectric mirror layer 22, whichis highlyreflec-
`tive for 2, and transmissive for A,. Such a beamsplitter, in
`particular its dielectric layer, can be more easily produced,
`when the angle of incidence of both light beam groups is
`smaller than 45°. Sharper and more acute angles of inci-
`dence make it easier to unite more than two light beam
`groups. Appropriate light dividers are known for example in
`color CCD cameras with three CCD elements for the dif-
`ferent colors, which in the application for a vehicle headlight
`howeverare passed through by light in the reverse direction.
`
`[0051] The diodes 14, 14' of diode arrays 12, 12' are,
`similar to that as described above, selectively supplied with
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`US 2002/0196639 Al
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`Dec. 26, 2002
`
`current either from a common source or from multiple
`separate control devices according to the respective objec-
`tive for illumination.
`Whatis claimed is:
`1. Vehicle headlight, comprising a two-dimensional array
`(2) of a plurality of electronic light emitter elements (4),
`which are arranged for emitting a plurality of parallel light
`beams(6), a collection lens (8), which is provided one focal
`length awayessentially parallel to the two-dimensionalarray
`and positioned for receiving the light emitted by the array,
`and a control electronic for
`the light emitter elements
`operatively associated [or energizing the light emitter ele-
`ments (4) individually or in groups.
`2. Vehicle headlight according to claim 1, wherein the
`light emitters (4) emit infrared light.
`3. Vehicle headlight according to claim 1, wherein the
`light emitters (4) emit visible light.
`4. Vehicle headhght according to claim 1, wherein some
`ofthe light emitters (4) emit infrared light and the remaining
`light emitters emit visible light.
`5. Vehicle headlight according to one of the preceding
`claims, wherein the light emitters (4) are laser diodes.
`6. Vehicle headlight according to one of claims 1 through
`4, wherein the light emitters (4) are LEDs.
`7. Vehicle headlight, comprising multiple two-dimen-
`sional arrays (12, 12'), which respectively comprise a plu-
`rality of electronic light emitting elements (14, 14’), which
`are arranged for emitting a plurality of parallel light beams
`(16. 16), whercin the light emitted by cach array has a
`wavelength which is different from the wavelength of the
`other arrays, and wherein the multiple arrays are so
`arranged, that their respective light beams mect in a light
`combiner (20), which directs the light bundlesof all arrays
`
`in parallel to a commoncollection lens (18), and a control
`electronic for the light emitter elements operatively associ-
`ated for energizing the light emitter elements (14, 14')
`individually or in groups.
`8. Vehicle headlight according to claim 7, wherein some
`of the arrays (12) emil infrared light and the remaining
`arrays (12') emit visible light.
`9. Vehicle headlight according to claim 7 or 8, wherein
`two or more arrays 912, 12') emit visible monochromiclight
`with respective different wavelengths, which when com-
`bined produce white light.
`10. Vehicle headlight according to one of the preceding
`claims, wherein a diffuser (10) is positioned in the path of
`the light beams (6) of one or more of the light emitters (4).
`11. Vehicle headlight according to claim 10, wherein the
`light diffuser (10) is positioned in close proximity to the
`collection lens (8).
`12. Vehicle headlight according to claim 10, wherein the
`light diffuser (10) is integrated in the collection lens(8).
`13. Vehicle headlight according to one of the preceding
`claims, wherein the control electronics is designed for
`selectively energizing light elements (4) in response to data
`received from sensors regarding thetraffic or environmental
`conditions.
`14. Vehicle headlight according to one of the preceding
`claims, wherein the control electronics is designed to pro-
`duce in someor all of the light emitters (4) light intensities,
`whichis enhanced or reduced than the normal light intensity
`of the ight emitters.
`15. Vehicle headlight according to one of the preceding
`claims, wherein the headlight is a front headlight.
`
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