IN THE UNITED STATES PATENT AND TRADEMARK OFFICE
`
`In re Patent of:
`
`Lebens et al.
`
`U.S. Patent No.: 6,488,390
`
`
`
`Issue Date:
`
`December 3, 2002
`
`Appl. Serial No.: 09/978,760
`
`Filing Date:
`
`October 16, 2001
`
`Title:
`
`COLOR-ADJUSTED CAMERA LIGHT AND METHOD
`
`
`
`
`
`
`
`PETITION FOR INTER PARTES REVIEW OF UNITED STATES PATENT
`
`NO. 6,488,390 PURSUANT TO 35 U.S.C. §§ 311–319, 37 C.F.R. § 42
`
`
`
`
`
`Exhibit LG-1001
`
`U.S. Patent No. 6,488,390 to Lebens, et al. (“’390 Patent”)
`
`
`
`
`

`

`(12> Ulllted States Patent
`Lebens et al.
`
`US006488390B1
`(16) Patent N6.=
`US 6,488,390 B1
`(45) Date of Patent:
`*Dec. 3, 2002
`
`(54) COLOR-ADJUSTED CAMERA LIGHT AND
`METHOD
`(75) Inventors: Gary A. Lebens, Chaska, MN (US);
`.
`Charles T- Bounh MmKIetOHka’ MN
`(US); Charles A. Lemalre, Apple
`Valley, MN (Us)
`
`_
`(73) AsslgneeZ
`
`_
`_
`_
`_
`Vlslen, Inc'> Eden Pralne> MN
`
`( * ) Notice:
`
`Subject' to any disclaimer, the term of this
`Patent 15 extended or adlusted under 35
`U50 154(1)) by 0 days-
`
`This patent is subject to a terminal dis-
`claimer.
`
`(21) APP1~N0-309/978’760
`(22) Filed;
`Oct 16, 2001
`
`Related US. Application Data
`
`(60) Continuation of application No. 09/627268, ?led 0111111- 28,
`2000 now Pat. No. 6305 818 which is a division of
`7
`7
`7
`7
`application No. 09/044,559, ?led on Mar. 19, 1998, now Pat.
`NO_ 6 095 661_
`7
`7
`(51) Int. Cl.7 ................................................ .. F21V 9/00
`(52) US. Cl. ..................... .. 362/231; 362/184; 362/185;
`362/208; 362/183; 362/800; 362/234; 362/11;
`362/ 13
`(58) Field of Search ............................... .. 362/157, 183,
`362/159, 184, 208, 800, 249, 11, 13, 234;
`315/224, 307, 291, 312, 360, 362
`
`(56)
`
`References Cited
`U_S_ PATENT DOCUMENTS
`
`370697654 A 12/1962 Hough ~~~~~~~~~~~~~~~~~~ ~~ 340/1463
`33663752 A
`5/1972 Froschle
`4208579 A
`6/1980 Scrivo et a1‘ """"""" " 250/227
`4,212,073 A
`7/1980 Balasubramanian ...... .. 364/562
`4,290,095 A
`9/1981 Schmidt ~~~~~~~~~~~~ n
`362/191
`4 346 329 A
`8/1982 Schmidt .................... .. 315/51
`
`FOREIGN PATENT DOCUMENTS
`0356680
`3/1990
`901638801
`2/1995 """" " GO1N/21/88
`/06846
`5/ 1991
`98/02716
`1/1998
`......... .. G01B/11/03
`
`EP
`“E50
`WO
`
`OTHER PUBLICATIONS
`
`“Copy of US. application Ser. No. 08/825,774 entitled High
`Speed Digital Video Serial Link”, 33 pgs., (Apr. 2, 1997).
`(List continued on neXt page.)
`Primary Examiner_stephen Husar
`Assistant Examiner—Bertrand Zeade
`(74) Attorney, Agent, or Firm—SchWegman, Lundberg,
`Woessner & Kluth, PA.
`(57)
`ABSTRACT
`
`Improved method and apparatus for hand-held portable
`illumination. A ?ashlight and corresponding method are
`described. The ?ashlight includes a housing, a plurality of
`LEDs, and an electrical circuit that selectively applies poWer
`from the DC voltage source to the LED units, Wherein the
`?ashlight is suitable for handheld portable operation by a
`user. In one embodiment, the ?rst electrical circuit further
`'
`'
`'
`'
`'
`'
`'
`includes a control circuit for ma1nta1n1n a redetermmed
`g p
`light output level of the LED units as a charge on a battery
`varies. In another embodiment, the control circuit maintains
`an average predetermined light Output level of the LED units
`as the charge on the battery Cell Varies by Changing a pulse
`Width or frequency as the charge on the battery cell varies to
`maintain a given average light output. Another aspect pro
`vides an illumination source that includes a light-emitting
`diode (LED) housing including one or more LEDs, and a
`control circuit that selectively applies poWer from a source
`of electric poWer to the LEDs, the control circuit substan
`tially maintaining a light output characteristic of the LEDs
`as a voltage of the voltage source varies over a range that
`Would otherWise vary the light output characteristic. Still
`another aspect provides an illumination source including a
`light-emitting diode (LED) housing including one or more
`LEDs' and a control circuit that selectivel a lies oWer
`’
`.
`y pp
`.p
`.
`from a source of electric poWer to the LEDs, thus maintain
`ing or Controlling a light Output Color Spectrum of the LEDS~
`
`(List continued on next page.)
`
`40 Claims, 11 Drawing Sheets
`
`151D
`
`Fm
`
`CONTROL CIRCUIT
`FOR LEDs
`
`VIDEO [MAGER
`
`1 cmcurr
`
`i
`
`‘m
`
`SEQ
`
`Exhibit LG-1001 Page 1
`
`

`

`US 6,488,390 B1
`Page 2
`
`US. PATENT DOCUMENTS
`
`,
`
`,
`
`/1991 Garriss
`
`. 348/371
`
`4/1985 Cusack ................... .. 33/174 L
`4,509,266 A
`6/1986 Herman . . . . .
`. . . .. 33/366
`4,592,147 A
`1/1987 Wyentetel
`4,639,139 A
`356/359
`2/1987 Helieue et el
`4,641,972 A
`356/376
`250/566
`5/1988 Karena etel- -
`4743773 A
`446/26
`4/1989 Spreggins
`4,820,229 A
`362/100
`5/1989 NIShiZeWe ete-
`4,831,504 A
`4,877,326 A 10/1989 Chadwick et a1- -------- -- 356/394
`4,882,498 A 11/1989 Cochran et el- ---------- -- 250/571
`4,893,815 A
`1/1990 Rowan ...................... .. 273/84
`4,914,289 A
`4/1990 Nguyen et al.
`250/223 B
`4,962,347 A 10/1990 Burroughs et al. ......... .. 320/48
`4,964,023 A 10/1990 NishiZawa et a1. ....... .. 362/100
`4,965,665 A 10/1990 Amir .............. ..
`358/101
`4,967,284 A 10/1990 Yoshida et a1
`-- 358/300
`4a972a093 A 11/1990 C0011“? ct a1~
`250/572
`4,974,138 A 11/1990 Negishi .................... .. 362/347
`2 13/1990 luengel "
`' 250/551
`5,015,918 A
`5/1991 Copeland
`__ 315/76
`5,051,825 A
`9/1991 Cochran eta
`. 358/106
`5,058,982 A 10/1991 KatZir _ _ _ _ _ _ _ _ _ _
`_ _ _ __ 385/33
`5,059,013 A 10/1991 Jain ......................... .. 359/503
`5,060,065 A 10/1991 Wasserman ............... .. 358/106
`5,065,035 A 11/1991 Juengel """ "
`250/551
`5’O72’127 A 12/1991 Cochran et a1‘ "
`250/572
`5,085,502 A
`2/1992 Womack et al.
`356/376
`5,172,005 A 12/1992 Cochran et a1. ..
`.... .. 250/57
`5,179,335 A
`1/1993 Nor . . . . . . . . . . . . . .
`. . . .. 320/21
`5,179,474 A
`1/1993 Bailey et a1. ............. .. 359/798
`5,279,513 A
`1/1994 Connelly .................. .. 446/219
`5,299,227 A
`3/1994 R056
`375/1
`2
`gogstaelt ~~~~~~~~~~~~~~~~ ~~
`356/360
`5,398,113 A
`3/1995 de Groot ..... ..
`362/157
`5,424,927 A
`6/1995 Schaller et aL
`348/126
`5,457,492 A 10/1995 Sasaki et a1_
`356/371
`5,465,152 A 11/1995 Bilodeau et a1_
`235/472
`5,468,950 A 11/1995 Hanson .......... ..
`5,546,189 A
`8/1996 Svetkoff et al. .......... .. 356/376
`5,561,525 A 10/1996 Toyonaga et al. ......... .. 356/360
`5,604,550 A
`2/1997 White ...................... .. 396/429
`
`,
`
`,
`
`0 en e a. ............. ..
`
`6/1997 Bieman et a1. ........... .. 356/374
`5,636,025 A
`7/1997 Bieman ........ ..
`356/376
`5,646,733 A
`5,680,215 A 10/1997 Huber et a1
`356/371
`5,745,176 A
`4/1998 Lebens _
`348570
`
`.. 356/371
`5,825,495 A 10/1998 Huber .... ..
`.... .. 356/237
`5,828,449 A 10/1998 King et a1. ..
`5,838,247 A 11/1998 Bladowski ........... .. 340/815.45
`5,890,794 A
`4/1999 Abtahi et a1. ............. .. 362/294
`6,084,631 A
`7/2000 Tonkin et a1.
`248/212
`6,095,661 A
`8/2000 Lebens et a1. ............ .. 362/184
`6,305,818 B1 * 10/2001 Lebens et a1. ............ .. 362/184
`
`OTHER PUBLICATIONS
`
`_
`
`”
`
`_
`
`_
`
`“Edmund Seienti?e Company 1993 Annual Referencing
`Catalog, Cylinder Lenses (CYL)”, catalog pg. 47.
`“Hewlett Packard Optotronics Designer’s Catalog, Techni
`cal Data entitled High power AllnGalP Amber and Red
`dish_()range Lamps”,PgS- 3—24 through 3_29) 1993
`Ballard, D.H., “Generalizing the Hough Transform to Detect
`Arbitrary Shapes , Pattern Recognition, 13 (2), Pergamon
`Press, PP- 183—194,(1981)
`Davies, E.R., Machine Vision: Theory, Algorithns, Practi
`calities, 2nd Edition, Academic Press, San Diego, pp.
`195_21(), (1997)_
`Gennert, M.A., et al., “Uniform Fontal Illumination of
`Planar Surfaces: Where to place the lamps”, Optical Engi
`.
`nee’ 1'15’ V01‘ 32’ NO‘ 6’ pp‘ 1261_1271’(Jl_m_' 1993)‘ _
`NOVIIH, A» “Fundamentals of machlne VISIOH LIghHHg”,
`Eleetre Conference Record, New York, NE pp- 435—443,
`(1993).
`Uber, G.T., “Illumination Methods for Machine Vision”,
`SPIE vol. 728 Optics, Illumination, and Image Sensing for
`Machine Wsmn’ pp‘; 93_102,’ (1,986)‘
`_
`_
`_
`Yang, H.S., et al., Determination of'the Identity, Position
`and Orientation of the Topmost ObJect in a Pile: Some
`Further Experiments”, IEEE International Conference on
`Robotics and Automation, 1, San Francisco. CA, 293—298,
`(1986).
`
`-
`
`-
`
`* cited by examiner
`
`Exhibit LG-1001 Page 2
`
`

`

`US. Patent
`
`Dec. 3, 2002
`
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`US 6,488,390 B1
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`Dec. 3, 2002
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`U.S. Patent
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`Dec. 3, 2002
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`US 6,488,390 B1
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`

`

`US 6,488,390 B1
`
`1
`COLOR-ADJUSTED CAMERA LIGHT AND
`METHOD
`
`This application is a continuation of US. application Ser.
`No. 09/627,268, ?led Jul. 28, 2000 (US. Pat. No. 6,305,
`818), Which is a divisional of US. application Ser. No.
`09/044,559, ?led Mar. 19, 1998 (US. Pat. No. 6,095,661),
`Which applications are incorporated herein by reference.
`
`FIELD OF THE INVENTION
`
`This invention relates to the ?eld of lighting, and more
`speci?cally to a method and apparatus of controlling and
`poWering a solid-state light source such as a light-emitting
`diode or LED, for a portable battery-poWered ?ashlight.
`
`BACKGROUND OF THE INVENTION
`
`There is a Widespread need for hand-held ?ashlights and
`lanterns. One common ?ashlight includes a tWo-cell battery
`for poWer, an incandescent lamp to emit light, and a simple
`single-pole sWitch to connect and disconnect the battery to
`the lamp. Other ?ashlights use other numbers of battery cells
`in order to provide a voltage suitable for various particular
`conditions. Lanterns often use a ?uorescent tube to emit
`light. Certain keychain fobs use a pair of hearing-aid cells
`and a red-light light-emitting diode (LED) in order to
`provide short-range lighting such as might be needed to ?nd
`a keyhole in the dark.
`Battery technology is such that as electrical poWer is
`WithdraWn from a battery cell, the voltage available across
`a given current load Will decrease. This decreased available
`voltage across the given load causes reduced light output,
`gradually dimming the light as the battery charge depletes.
`Further, LEDs have voltage, current, and poWer param
`eters that must be controlled in order to maximize device
`life. Commonly, a current-limiting resistor is placed in series
`With an LED in order that only a portion of the voltage drop
`from the battery is across the LED and the rest of the voltage
`drop is across the resistor. This voltage drop and correspond
`ing poWer loss in the resistor is dissipated as Waste heat,
`Which is inef?cient for a ?ashlight Which should be designed
`to emit light.
`In addition, it is aWkWard or difficult to determine the
`amount of remaining charge in a battery cell, generally
`requiring removal of the battery from the ?ashlight in order
`to measure the remaining charge. In addition, the cost of a
`separate measurement device can be a negative for this
`market. Some battery cells today include a built-in liquid
`crystal indicator for the charge in the cell, but such a solution
`requires a separate measurement device/indicator for each
`battery, and requires removal of the battery from the ?ash
`light in order to perform the measurement and observe the
`indication of remaining poWer.
`
`SUMMARY OF THE INVENTION
`
`The present invention provides a method and apparatus
`for an LED. ?ashlight or other LED illumination source. In
`one embodiment, a ?ashlight is described. The ?ashlight
`includes a ?ashlight housing suitable for receiving therein
`and/or mounting thereon at least one DC voltage source such
`as a battery. The ?ashlight also includes a light-emitting
`diode (LED) housing connected to the ?ashlight housing,
`the LED housing including a ?rst plurality of LED units
`that each emit light and have a re?ector for collimating the
`emitted light forWardly therefrom generally along an LED
`optical axis, the ?rst plurality of LED units including at least
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`55
`
`60
`
`65
`
`2
`seven individual LED units. The ?ashlight also includes a
`?rst electrical circuit that selectively applies poWer from the
`DC voltage source to the LED units, Wherein the ?ashlight
`is of such compact siZe and loW Weight as to be suitable for
`single-handed portable operation by a user, the ?ashlight
`further having a purpose of providing general-purpose illu
`mination.
`In one embodiment, the LED optical axes of the ?rst
`plurality of LED units in the ?ashlight are substantially
`parallel to one another. In one such embodiment, the ?ash
`light further includes a second plurality of LED units that
`each emit light and have a re?ector for collimating the
`emitted light forWardly therefrom generally along an LED
`optical axis, Wherein the LED optical axes of the second
`plurality of LED units converge or diverge from one another
`forWardly from the housing.
`In another embodiment, an optical spread angle of the ?rst
`plurality of LED units in the ?ashlight are substantially
`equal to one another. In one such embodiment, the ?ashlight
`further includes a second plurality of LED units that each
`emit light and have a re?ector for collimating the emitted
`light forWardly therefrom generally along an LED optical
`axis, Wherein an optical spread angle of the second plurality
`of LED units are substantially equal to one another, and
`different than the optical spread angle of the ?rst plurality of
`LED units.
`In yet another embodiment, the LED units are connected
`in a parallel-series con?guration With at least tWo LED units
`coupled in parallel to one another and in series With at least
`one other LED unit, and the DC voltage source includes at
`least three battery cells connected in series.
`In still another embodiment, the ?rst electrical circuit
`further includes a control circuit for maintaining a prede
`termined light output level of the LED units as a charge on
`the battery cell varies. In one such embodiment, the control
`circuit maintains an average predetermined light output level
`of the LED units as the charge on the battery cell varies by
`increasing a pulse Width or a pulse frequency as the charge
`on the battery cell decreases. In another such embodiment,
`the control circuit maintains an average predetermined light
`output level of the LED units by measuring a battery voltage
`and adjusting a pulse Width or a pulse frequency or both to
`maintain the average light output at the predetermined level.
`In still another such embodiment, the control circuit main
`tains an average predetermined light output level of the LED
`units by measuring an average light output and adjusting a
`pulse Width or a pulse frequency or both to maintain the
`measured average light output at the predetermined level.
`Another aspect of the present invention provides a ?ash
`light including: (a) a ?ashlight housing, the housing being
`suitable for at least one of receiving therein and mounting
`thereon at least one DC voltage source that includes at least
`one battery cell; (b) a light-emitting diode (LED) housing
`connected to the ?ashlight housing, the LED housing includ
`ing one or more ?rst LED units that each emit light and have
`a re?ector for collimating the emitted light forWardly there
`from generally along an LED optical axis; and (c) a ?rst
`electrical circuit that selectively applies poWer from the DC
`voltage source to the LED units, the ?rst electrical circuit
`further including a control circuit for maintaining a prede
`termined light output level of the LED units as a charge on
`the battery cell varies; Wherein the ?ashlight is of such
`compact siZe and loW Weight as to be suitable for single
`handed portable operation by a user, the ?ashlight further
`having a purpose of providing general-purpose illumination.
`In one such embodiment, the ?rst LED units being a ?rst
`plurality of LED units, Wherein the LED optical axes of the
`
`Exhibit LG-1001 Page 14
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`

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`US 6,488,390 B1
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`3
`?rst plurality of LED units are substantially parallel to one
`another. In another such embodiment, the ?ashlight-further
`includes a second plurality of LED units that each emit light
`and have a re?ector for collimating the emitted light for
`Wardly therefrom generally along an LED optical axis,
`Wherein the LED optical axes of the second plurality of LED
`units converge or diverge from one another forWardly from
`the housing.
`In another such embodiment, the ?rst LED units are a ?rst
`plurality of LED units, Wherein an optical spread angle of
`the ?rst plurality of LED units are substantially equal to one
`another. In yet another such embodiment, the ?ashlight
`further includes a second plurality of LED units that each
`emit light and have a re?ector for collimating the emitted
`light forWardly therefrom generally along an LED optical
`axis, Wherein an optical spread angle of the second plurality
`of LED units are substantially equal to one another, and
`different than the optical spread angle of the ?rst plurality of
`LED units.
`Another aspect of the present invention provides a method
`of providing general-purpose illumination of such compact
`siZe and loW Weight as to be suitable for single-handed
`portable operation by a user, including the steps of: (a)
`providing one or more ?rst LED units that each emit light
`and have a re?ector for collimating the emitted light for
`Wardly therefrom generally along an LED optical axis; (b)
`selectively applying poWer from a DC voltage source to the
`LED units; and (c) maintaining a predetermined light output
`level of the LED units as a charge on the battery cell varies
`by controlling the step
`In one embodiment, the step of maintaining maintains an
`average predetermined light output level of the LED units as
`the charge on the battery cell varies by increasing a pulse
`energy or a pulse frequency as the charge on the battery cell
`decreases. In another embodiment, the step of maintaining
`maintains an average predetermined light output level of the
`LED units by measuring a battery voltage and adjusting a
`pulse Width or a pulse frequency or both to maintain the
`average light output at the predetermined level. In still
`another embodiment, the step of maintaining maintains an
`average predetermined light output level of the LED units by
`measuring a light output and adjusting a pulse energy or a
`pulse frequency or both to maintain an average light output
`at the predetermined level.
`Yet another aspect of the present invention provides an
`illumination source, that includes (a) a light-emitting diode
`(LED) housing including one or more LEDs; and (b) a
`control circuit that selectively applies poWer from a source
`of electric poWer to the LEDs, the control circuit substan
`tially maintaining a light output characteristic of the LEDs
`as a voltage of the voltage source varies over a range that
`Would otherWise vary the light output characteristic. In one
`such embodiment, the light output characteristic that is
`maintained is light output intensity. In another such
`embodiment, the control circuit maintains the light output
`intensity of the LED units as the voltage of the DC voltage
`source varies by increasing a pulse Width, a pulse energy, or
`a pulse frequency as the voltage of the DC voltage source
`decreases. In another such embodiment, the control circuit
`maintains an average predetermined light output level of the
`LED units by measuring a voltage and adjusting a pulse
`energy or a pulse frequency or both to maintain the average
`light output at the predetermined level. In yet another such
`embodiment, the control circuit maintains an average pre
`determined light output level of the LED units by measuring
`an average light output and adjusting a pulse Width or a pulse
`frequency or both to maintain the measured average light
`output at the predetermined level.
`
`4
`Another aspect of the present invention provides a
`battery-poWered portable ?ashlight (100) including: a casing
`(110) suitable to hold a battery; one or more light-emitting
`devices (LEDs) (150) mounted to the casing; a sWitch (140)
`mounted to the casing; and a control circuit (130) coupled to
`the battery, the LEDs, and the sWitch, Wherein the control
`circuit drives the LEDs With electrical pulses at a frequency
`high enough that light produced by the LEDs has an appear
`ance to a human user of being continuous rather than pulsed,
`and Wherein the LEDs have proportion of on-time that
`increases as remaining battery poWer decreases. One such
`embodiment further includes a feedback circuit that controls
`the pulses so that light intensity produced by the LEDs, as
`perceived by the human user, is substantially constant across
`a greater range of battery poWer or voltage than a corre
`sponding range for Which light intensity is equally constant
`Without the feedback circuit. In one such embodiment, the
`feedback circuit measures a light output of the LEDs.
`Another such embodiment further includes a battery
`voltage-measuring circuit coupled to the control circuit.
`Yet another aspect of the present invention provides a
`method for driving battery-poWered portable ?ashlight (100)
`having a casing (110), a DC poWer source mounted to the
`casing, one or more solid-state light-emitting device (LEDs)
`(150) mounted to the casing, the method including the steps
`of: receiving input from a user; and based on the received
`input, generating a series of pulses to drive the LEDs such
`that the LEDs have proportion of on-time that increases as
`remaining battery poWer decreases.
`Still another aspect of the present invention provides an
`illumination source including (a) a light-emitting diode
`(LED) housing including one or more LEDs; and (b) a
`control circuit that selectively applies poWer from a source
`of electric poWer to the one or more LEDs, the control circuit
`maintaining a predetermined light output color spectrum of
`the one or more LEDs as a voltage of the source of electric
`poWer varies. In one such embodiment, the one or more
`LEDs comprise one or more LEDs having a ?rst character
`istic color spectrum output and one or more LEDs having a
`second characteristic color spectrum output, the ?rst char
`acteristic color spectrum output different from the second
`characteristic color spectrum output, and the control circuit
`controls a pulse characteristic in order to control the pro
`portion of light output having the ?rst characteristic color
`spectrum output to that having the second characteristic
`color spectrum output. In another such embodiment, the one
`or more LEDs comprise one or more LEDs having a
`characteristic color spectrum output that varies based on
`applied current, and the control circuit controls a pulse
`current in order to control the characteristic color spectrum
`output.
`Yet another aspect of the present invention provides an
`illumination source that includes (a) a light-emitting diode
`(LED) housing including one or more LEDs; and (b) a
`control circuit that selectively applies poWer from a source
`of electric poWer to the LEDs to adjust a light output color
`spectrum of the one or more LEDs.
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`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 shoWs one embodiment of the present invention, a
`schematic representation of a handheld LED ?ashlight 100.
`FIG. 2 is a circuit block diagram of an LED ?ashlight
`circuit 200, Which circuit is used in some embodiments of
`LED ?ashlight 100 of FIG. 1 or LED light source in
`camcorder 500 of FIG. 5 or other devices such as machine
`vision systems.
`
`65
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`Exhibit LG-1001 Page 15
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`US 6,488,390 B1
`
`5
`FIG. 3 a circuit block diagram of an LED ?ashlight circuit
`300, Which circuit is used in some embodiments of LED
`?ashlight 100 of FIG. 1 or LED light source in camcorder
`500 of FIG. 5 or other devices such as machine-vision
`systems.
`FIG. 4 a circuit block diagram of an LED ?ashlight circuit
`400, Which circuit is used in some embodiments of LED
`?ashlight 100 of FIG. 1 or LED light source in camcorder
`500 of FIG. 5 or other devices such as machine-vision
`systems.
`FIG. 5 is a diagram shoWing a controlled LED light
`source is integrated into a handheld camcorder 500.
`FIG. 6 is a graph of color spectrum versus current for an
`LED to be used in one embodiment of the present invention.
`FIG. 7 is circuit block diagram of an LED illumination
`device circuit 700, Which circuit is used in some embodi
`ments of LED ?ashlight 100 of FIG. 1 or LED light source
`in camcorder 500 of FIG. 5 or other devices such as
`machine-vision systems.
`FIG. 8 is circuit block diagram of an LED illumination
`device circuit 700 that uses a current mirror.
`FIG. 9 is a graph of color spectrum (photoluminescence)
`versus temperature for an LED to be used in one embodi
`ment of the present invention.
`FIG. 10 is circuit block diagram of a machine vision
`system using an LED illumination device according to the
`present invention.
`FIG. 11 is circuit block diagram of an LED illumination
`device according to the present invention.
`
`DESCRIPTION OF THE PREFERRED
`EMBODIMENT
`In the folloWing detailed description of the preferred
`embodiments, reference is made to the accompanying draW
`ings that form a part hereof, and in Which are shoWn by Way
`of illustration speci?c embodiments in Which the invention
`may be practiced. It is understood that other embodiments
`may be utiliZed and structural changes may be made Without
`departing from the scope of the present invention.
`The present invention takes advantage of the ef?ciency of
`high-intensity, light-emitting diodes (LEDs) in the visible
`spectrum and/or infra-red (IR) or ultra-violet (UV), arranged
`in various patterns, the loW-voltage properties of CMOS
`integrated circuits and components, and the ef?ciency
`derived from sWitching the current to and limiting the
`duration of current to the LEDs to project light ef?ciently
`and With constant brightness even as the battery supply
`voltage decays over time. The invention takes advantage of
`the dynamic impedance of the LEDs Which causes the
`voltage across the LED to rise rapidly relative to the current
`?oW through the LED to limit the initial current ?oW to the
`LED, When battery voltage is highest, to prevent Wire bond
`heating from causing premature failure of the LEDs. The
`present invention controls the current ?oW duration (pulse
`Width) to limit poWer dissipation in the LEDs during the
`LEDs’ on state, and increasing the pulse Width as the battery
`voltage decreases over time to maintain substantially con
`stant perceived or average LED intensity over the course of
`the battery’s life. The invention controls the sWitching
`frequency of the pulse Width to further control the LED
`intensity and poWer dissipation While maintaining a constant
`light output from the LEDs as perceived or visible to the
`human eye, or a light-sensing device, e.g., camera, night
`vision scope, CMOS and CCD sensor and piXel arrays. The
`present invention provides a compact, portable light source,
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`preferably siZed to be readily hand-held, for illuminating an
`object, several objects, or areas for human use and/or
`machine operation. In one embodiment, the invention mea
`sures battery voltage and in turn regulates the LED intensity.
`In another embodiment, the present invention uses a light
`sensing device such as a light-sensing transistor or light
`detecting diode (LDD) in proXimity to the output LED(s) to
`measure the average brightness and further regulate the
`LEDs’ output.
`Another embodiment of the present invention provides
`operator-selectable control of the pulse frequency and/or the
`pulse Width to provide a reduced apparent brightness in
`order to increase battery life in situations When maXimum
`brightness is not required. In one such pulse-frequency
`embodiment, the apparent (visible) pulse frequency Would
`provide a stroboscope effect for safety or entertainment. In
`this embodiment, the visibly interrupted or pulsed pulse
`train may include repetitive pulses or a coded sequence as in
`Morse code “SOS” or a predetermined passWord or security
`string of pulses that may then he used as a key or identi?er.
`A further re?nement of this embodiment Would provide the
`user With a method for strobing out a message. It is under
`stood that What appears to be a single visible pulse may
`actually include a high-frequency series of pulses in order to
`increase the apparent brightness of a single pulse While also
`protecting the LEDs from excessive poWer dissipation. In
`yet another pulse-frequency embodiment of the invention, a
`variable or adjustable constant sequence pulse train is estab
`lished for the accurate measurement of the velocity or
`frequency of an object in motion or vibration.
`Another embodiment of the present invention uses vari
`ous colored LEDs for specialiZed purposes. In one such
`embodiment, long-Wavelength LEDs, 660 nm or longer, are
`used to provide underWater divers or aquarium enthusiasts a
`light source for observing undersea life at night Without
`adversely affecting the nocturnal activities of such Wildlife.
`This functionality is also useful for tropical aquarium oWn
`ers Who also Wish to observe the nocturnal activities of the
`occupants of their aquariums. In another such embodiment,
`short-Wavelength blue LEDs are used With a UV ?lter to
`vieW ?uorescing materials, including but not limited to:
`taggants, stamps, security codes and security seals. As UV
`LEDs become readily available (such as those announced as
`made by IBM Corporation in the Mar. 9, 1998 issue of
`Electronic Engineering Times, page 39), these could be used
`in place of the blue LEDs. In other embodiments, a suitable
`LED normally emitting in the blue spectrum, for eXample
`made from GaN (gallium nitride) or InGaN (indium gallium
`nitride), is pulsed by pulses of suf?ciently high current to