`
`IN THE UNITED STATES PATENT AND TRADEMARK OFFICE
`
`In re Patent of:
`
`Lebens et al.
`
`U.S. Patent No.:
`
`6,095,661
`
`
`
`Issue Date:
`
`August 1, 2000
`
`Appl. Serial No.:
`
`09/044,559
`
`Filing Date:
`
`March 19, 1998
`
`Title:
`
`METHOD AND APPARATUS FOR AN L.E.D.
`
`FLASHLIGHT
`
`
`PETITION FOR INTER PARTES REVIEW OF UNITED STATES PATENT
`NO. 6,095,661 PURSUANT TO 35 U.S.C. §§ 311–319, 37 C.F.R. § 42
`
`
`Exhibit LG-1005
`
`U.S. Patent No. 5,010,412 (“Garriss”)
`
`

`

`United States Patent 5)
`5,010,412
`[11] Patent Number:
`Apr. 23, 1991
`[45] Date of Patent:
`Garriss
`
`[54] HIGH FREQUENCY, LOW POWER LIGHT
`SOURCE FOR VIDEO CAMERA
`
`[75]
`
`Inventor:
`
`Gregory M. Garrise, Federal Way,
`Wash.
`
`{73] Assignee: The Boeing Company, Seattle, Wash.
`(21] Appl. No.: 290,581
`{22] Filed:
`Dee. 27, 1988
`(SE) Eat. C15 cececcscscstensene HO4N 3/12; HO4N 7/18
`[52] US. CM ceccccccccnctcssccsecsessssneosen 388/240; 358/107;
`356/23; 354/129; 354/132
`[58] Field of Search ............... 358/107, 125, 212, 240,
`358/241, 100; 356/23; 362/3, 11, 800; 354/129,
`132, 140, 414
`
`[36]
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`6/1973 Scharlack occ 313/209
`3,737,722
`3,800,204 3/1974 Kenny....
`vee 318/480
`4,161,018 7/1979 Bri
`wee 362/104
`4,164,008
`8/1979 Miller et al.
`‘see 362/103
`A211,953 T/1GBO Raay ....ercscccoscseresersasseseneseasere 313/53
`4,264,845 4/1981 Bednarz ..
`eos 313/323
`4,298,869 11/1981 Okuno....
`see 340/782
`4,459,645
`7/1984 Glattercesses 362/104
`
`
`
`
`
`seseene 362/240
`
`6/1987 McDermott etal. ....
`4,677,533
`
`seseas 250/371
`4,882,498 11/1989 Cochran etal. .....
`
`Primary Examiner—John K. Peng
`Attorney, Agent, or Firm—Dellett, Smith-Hill & Bedell
`(57}
`ABSTRACT
`A strobe light provides uniformly intense, monochro-
`matic illumination of an object photographed by a video
`camera. Thestrobe light includes a circuit board having
`a central aperture and a plurality of light-emitting di-
`odes mountedon the circuit board and generally sur-
`rounding the aperture. The circuit board is attached to
`the camera with the aperture positioned in front of the
`camera lens such that the video camera views the object
`through the aperture as the diodes illuminate the object.
`Thestrobe light further includes an oscillator providing
`an output square wave signal of adjustable frequency
`and duty cycle. A transistor switch controlled by the
`square wave signal periodically connects a constant
`voltage across the diodes, thereby causing the diodes
`simultaneously to generate flashes of light with a fre-
`quency and duty cycle determined by the square wave
`signal.
`
`13 Claims, 2 Drawing Sheets
`
`
`
`Exhibit LG-1005 Page 1
`
`LGELEM0002957
`
`Exhibit LG-1005 Page 1
`
`

`

`U.S. Patent
`
`Apr. 23, 1991
`
`5,010,412
`
`Sheet 1 of 2
`
`Exhibit LG-1005 Page 2
`
`LGELEM0002958
`
`Exhibit LG-1005 Page 2
`
`

`

`US. Patent
`
`Apr. 23, 1991
`
`Sheet 2 of 2
`
`5,010,412
`
` oe oD ae ae OD Oe ae Oe ow Om aD an OD Da a GP oO
`78
`
`66
`
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`i
`
`Loof
`
`ol Il
`
`32
`
`74
`
`FIG.4
`
`Exhibit LG-1005 Page 3
`
`LGELEM0002959
`
`i
`
`‘
`'
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`i
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`
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`
`,
`
`FIG. 3
`
`+ S
`
`TROBE
`SIGNAL
`
`40
`
`Exhibit LG-1005 Page 3
`
`

`

`1
`
`5,010,412
`
`2
`graphed by a video camera includes a plurality of
`. monochromatic light-emitting diodes (LEDs) mounted
`on a surface of a circuit board or thelike having a cen-
`tral aperture, with the diodes generally disposed in
`surrounding relation to said aperture. The LEDs are
`thereby arranged and directed in a pattern providing
`uniform illumination of the object. The circuit board is
`attached to the video camera such that the video cam-
`era views the object through the aforementioned aper-
`ture.
`In accordance with a feature of the invention, an
`oscillator supplies an output signal of adjustable fre-
`quency and duty cycle and this oscillator output signal
`controls operation of a switch connecting a regulated
`voltage source to theaforementioned LEDs, causing
`the LEDs to generate pulses of uniformly intense,
`monochromatic light. In accordance with a further
`aspect of the invention, the oscillator operates when
`enabled by a synchronizing signal, produced by the
`camera, indicating when the camera starts acquiring an
`image. The LEDs are energized only when the camera
`is acquiring an image, minimizing the load ofthe strobe
`light on its power source such as, for example, the cam-
`era battery.
`It is accordingly an object of the present invention to
`provide an improved light source that generates uni-
`formly intense, monochromatic pulses of light over a
`range of frequencies and duty cycles.
`It is another object of the present invention to pro-
`vide an improved strobe light that is light weight and
`efficient, and operates from a low voltage power
`source.
`It is a further object of the invention to provide an
`improved strobe light
`that is rugged, requires little
`maintenance and generates little electrical noise or heat.
`The subject matter of the present invention is particu-
`larly pointed out and distinctly claimed in the conchud-
`‘ing portion of this specification. However, both the
`organization and method of operation of the invention,
`together with further advantages and objects thereof,
`may best be understood by reference to the following
`description taken with the accompanying drawings
`wherein like reference characters refer to like elements.
`
`HIGH FREQUENCY, LOW POWER LIGHT
`SOURCE FOR VIDEO CAMERA
`
`BACKGROUND OF THE INVENTION
`
`The present invention relates to light sources and in
`particular to a high frequency, low powerlight source
`employing light emitting diodes for illuminating an
`object photographed by a portable video camera.
`Inspection systems sometimes employ a video camera
`to produce video signals representing light intensity at
`regularly spaced points on the surface of an object, for
`examplea machinepartto be engaged by an industrial
`robot. When a “frame grabber” converts the video
`signals into gray scale bit map data, a control computer
`can analyze the bit map data and determine the shape
`and position of the part. Some inspection systems use a
`variable frequency strobe light for illuminating a rotat-
`ing or oscillating machine part monitored by the video
`camera to provide data representing the object as it
`appears at one or more selected positions during mo-
`tion.
`It is usually preferable that a light source uniformly
`illuminate a part under inspection. For example,if ambi-
`ent ligiit casts non-uniform shadows on the part, the
`camera can be fitted with a narrow bandlightfilter for
`filtering out wavelengths of light other than the band of
`the light spectrum produced by the monochromatic
`light source. Since the intensity of ambient light “noise”
`within the narrow band is negligibly small compared
`with the intensity of the source, the ambientlight inter-
`feres less with the monitoring process.
`The light source should be light weight and rugged.
`It should require minimal maintenance, provide uniform
`illumination, generate little electrical noise or heat, and
`should not require a power source different from the
`one Operating the camera. Incandescent, xenon, and
`fluorescent lights have been used as light sources, but
`have been found inconvenient or unacceptable in some
`applications because they require large, high voltage
`powersupplies or generate too much heat or electrical
`noise. Such prior art light systems may also be too
`heavy or too fragile or may not be able to operate at a
`sufficiently high frequency or sufficiently low duty
`cycle.
`Fiber optic ring lights provide a low infrared, uni-
`form circle of light, but require a high intensity incan-
`descent
`lamp 23 a source illuminator. The lamp is
`housed in a separate unit, and light is transmitted down
`a large diameter fiber optic cable to the ring light. The
`illuminator housings typically are very large in compar-
`ison to the ring light, require frequent replacement of
`the incandescent lamp, and generate large amounts of
`heat. In addition, the fiber optic cable coupling the lamp
`housing to the ring light is prone to internal fracturing
`due to the normal motions of a robotic end effector,
`requiring replacement. Fluorescent and cold cathode
`ring lights eliminate some of the above drawbacks in
`that they are lightweight, generate minimal amounts of
`heat, and are uniform. However, problems inherent
`with these types of light sources are their requirement
`of a high voltage (> 200 V.) power supply, mechanical
`fragility and low light output.
`SUMMARY OF THE INVENTION
`
`In accordance with an embodiment of the present
`invention, a light source for providing uniformly in-
`tense, monochromatic illumination of an object photo-
`
`.
`
`om ie]
`
`ee0
`
`40
`
`350
`
`35
`
`6
`
`BRIEF DESCRIPTION OF THE DRAWING
`
`FIG. 1 is an elevational view of a strobe light flash
`assembly in accordance with the present invention as
`mounted on a video camera;
`FIG.2 is a front view of the strobe light flash assem-
`bly of FIG. 1;
`FIG.3 is a combination block and schematic diagram
`of a strobe light in accordance with the present inven-
`tion; and
`FIG.4 is a schematic diagram ofthe driver circuit of
`FIG.3.
`
`DESCRIPTION OF THE PREFERRED
`EMBODIMENT
`
`Referring to FIGS. 1 through 3, a light source in
`accordance with the present invention includes a flash
`assembly 10 mounted upon a circuit board 12 having a
`central aperture 14. A set of light-emitting diodes
`(LEDs) 16 and resistors 18 are positioned on circuit
`board 12 in surrounding relation to the aperture, while
`a protective, transparent plastic cap 20 suitably covers
`circuit board 12, LEDs 16 and resistors 18. Microstrip
`conductors on circuit board 12 connect LEDs 16 in
`
`Exhibit LG-1005 Page 4
`
`LGELEM0002960
`
`Exhibit LG-1005 Page 4
`
`

`

`5,010,412
`
`— 0
`
`25
`
`4
`3
`center of a biasing voltage divider comprising resistors
`series with resistors 18 between terminals 22 on the
`70 and 72 connected between + V and ground. A resis-
`underside of the board. When a strobe signal pulse is
`tor 74 returns the collector of transistor 66 to ground,
`applied across terminals 22, LEDs 16 generate a flash of
`while a switch 76 operated by push button 32 of FIG. 1
`light. The flash assembly 10 is desirably mounted on the
`selectively grounds the emitter of transistor 66 through
`housing 28of a video camera 24 by means of supports |
`27, with lens 26 of camera 24 being positioned behind
`resistor 78. The output of driver circuit 40 is derived
`between +V and the emitter of transistor 66.
`aperture 14 whereby camera 24 can record an image of
`When a user wishes the strobe light to illuminate
`an object 11 well illuminated by the flash from LEDs
`16.
`object 11 continuously, he closes switch 76 by operating
`push button 32, thereby causing current to flow from
`A driver circuit 40 which may be installed within
`the +V voltage source to ground via diodes 16 and
`housing 28 of camera 24 generates a strobe signal ap-
`resistors 18 of FIG. 3 and resistor 78 of FIG. 4. For
`plied to the terminals 22 via a connector cable 30 ex-
`tending between flash assembly 10 and camera housing
`stroboscopic flash operation, the user opens switch 76
`via push button 32 to the position shown and adjusts
`28. Pushbuttons 31 and 32 mounted on housing 28 can
`switch 56 using push button 31 to select the appropriate
`be employed to permit a user to select whether the
`strobe signal driving LEDs 16 is synchronized to cam-
`synchronizing mode. In one selected position of switch
`50, contact 50a closes, connecting the +V voltage
`era operation and whetherit is continuous or an oscillat-
`source to node §2, while contact 505 opens. When ener-
`ing square wave. When the strobe signal is continuous,
`the LEDs steadily illuminate object 11. When the strobe
`gized, timer 64 acts as an oscillator continuously pro-
`ducing a square wave signal at pin 3 of frequency and
`signal oscillates, the LEDs periodically flash to illumi-
`nate object 11 with a frequency and duty cycle as may
`duty cycle respectively controlled by the settings of
`resistors 54 and 58.
`be controlled by knobs 33 and 34 also mounted on cam-
`The square wave outputsignal at pin 3 turns transis-
`era housing 28.
`Camera 24 generates video signals representing the
`tor 66 on and off. When transistor 66 turns on, current
`flows from. source + V to ground through diodes 16 and
`light intensity at regularly spaced points on the surface
`resistors 18 of FIG. 3 and throughtransistor 66 of FIG.
`of object 11 as illuminated by diodes 16. These signals
`may, for example, be conveyed via an external cable 36
`4. As the current flows through diodes 16,
`it causes
`to a conventional “frame grabber” (not shown) for
`them to emit light, but when transistor 66 turns off,
`converting the video signals into gray scale bit map
`current ceases to flow through the diodes. Thus, diodes
`data. A computer can analyze the bit map data output of
`16 generate pulses or flashes of light with a frequency
`the frame grabber and determine the shape and position
`and duty cycle determined by the square wave output
`of the timer 64 which the user may adjust using knobs
`of illuminated object 11. In an alternative embodiment,
`33 and 34 respectively.
`a frame grabber may be mounted within camera hous-
`ing 28, and in such embodimentcable 36 conveysthe bit
`When the operator selects a second position of switch
`§0, contact 505 closes to the position shown and contact
`map data from the frame grabber to.a computer.
`Referring in particular to FIG. 3, twelve sets of four
`50a opens to the position shown. Contact 505 then cou-
`LEDs 16 mounted on circuit board 12 are each con-
`ples the synchronizing output signal of the camera to
`nected in series with separate resistors 18 betweenter-
`the base of transistor 51. The camera’s synchronizing
`means 41 drives the synchronizing signal high when
`minals 22 of the flash assembly. Asillustrated in FIG.2,
`the sets of four LEDs, each comprising a square array,
`acquiring an image and drives the synchronizing signal
`are uniformly spaced around board 12 and are posi-
`low whenit is not acquiring an image. Forexample, the
`tioned for illuminating an object “seen” by the camera.
`video element of a typical video camera comprises an
`The driver circuit 40, energized by a regulated d.c.
`array of charge-coupled devices (CCDs) each receiving
`light reflected by a separate area of the object being
`voltage source 42 (+ V) suitably powered from a typi-
`cal camera power supply mounted within the camera
`monitored by the camera. When light strikes such a
`housing 28, provides the strobe signal across terminals
`charge coupled device element, it stores charge in pro-
`22. One terminal of driver circuit 40 is grounded to
`portion to the intensity and duration of light. After
`housing 28 while another input terminal of driver cir-
`allowing light to strike the CCD array for a short per-
`iod, the charge distribution on the array represents the
`cuit 40 receives a synchronizing signal (SYNC) from
`the camera.
`light intensity distribution as monitored by the camera
`and after thus capturing the image on the CCD array,
`Referring to FIG.4, the driver circuit 40 comprises a
`the camera generates a video signal by shifting the
`switch 50 controlled by the aforementioned push button
`31 mounted on the camera housing. One contact 50a of
`charges out of the array and converting them to a se-
`switch 50 selectively connects regulated voltage source
`quence of voltages proportional to the charges. The
`camera repeats operations of storing charges in the
`+V directly to a circuit node 52. Another contact 505
`selectively couples the synchronizing output signal of
`CCD array and shifting them out, thereby providing a
`the camera to the base of npn transistor $1. The collec-
`video signal representing a sequence of images. The
`frame grabber digitizes the video signal to produce bit
`tor of transistor 51 is tied to +V while the emitter
`thereof is connected to node 52. Variable resistor 34
`map data.
`i]
`While the camerais capturing an image by allowing
`controlled by knob 33 of FIG. 1 is connected between
`charge to build up on the CCD array,
`the camera’s
`node $2 and a node 56. In series therewith is another
`variable resistor 88 controlled by knob 34 of FIG. 1 and
`synchronizing means drives its output synchronizing
`signal high. This signal is normally used to synchronize
`deposed between nodes 56 and 60 respectively con-
`nected to terminal 7, and to terminals 2 and 6, of a con-
`operations of the video camera and the frame grabber or
`ventional type 555 timing circuit 64. A capacitor 62
`other device such as a video recorder receiving the
`returns node 60 to ground to complete a time constant
`video signal outputof the camera. In the present circuit,
`circuit. Output pin 3 of timer 64 drives the base of a pnp
`this synchronizing signal also turns on transistor 51 of
`transistor 66 through a resistor 68, also coupled to the
`FIG. 4, with switch contact 506 closed, thereby cou-
`
`40
`
`-
`45
`
`35
`
`65
`
`Exhibit LG-1005 Page 5
`
`LGELEM0002961
`
`Exhibit LG-1005 Page 5
`
`

`

`20
`
`30
`
`40
`
`pling voltage source +V to node 52 and causing timer
`64 to operate. Timer 64 produces a square wavesignal
`at pin 3 initially synchronized with the sync signal from
`the camera and oscillating with frequency and duty
`cycle controlled by resistors 54 and 58. The square
`wave signal turns transistor 66 on and off for periodi-
`cally energizing the LEDs as the video camera is ac-
`quiring an image. The timer 64 can alternatively be set
`to provide only one high frequency square wave half
`cycle at pin 3, to generate one flash timed with each
`camera sync pulse. When the camera is subsequently -
`_busy shifting charges out of the CCD array, the camera
`drives its output synchronizing signal low, and as the —
`synchronizing signal goes low,it turns off transistor 51
`of FIG. 4 for disconnecting the + V source from node
`52. The output oftimer 64 goes low, shutting off transis-
`tor66 and preventing current from flowing through the
`LEDs. Thus, the strobe light only flashes when the
`camera is capturing an image and does notflash when
`the camera is processing data, minimizing the drain of
`the camera battery 44 of FIG.3.
`The strobe light of the present invention provides
`uniformly intense, monochromatic illumination of an
`object photographed by a video camera system. Timer
`64 can flash the LEDs at frequencies (and correspond-
`ingly short pulse widths) up to 10 MHz, as opposed to
`30-100 KHz maximum frequency of xenon strobe
`lights. The frequency and duty cycle ofthe strobe light
`are accurately controllable over wide ranges. Switch-
`ing the lights at a high frequency, low duty cycle rate
`advantageously increases the light output by raising the
`current level while the minimized duty cycle prevents
`heating of the diodes and moderately improves diode
`life. Unlike laser or incandescentstrobe lights, the LED
`strobe light is rugged, light weight and efficient, and
`operatesfrom a low voltage power source. The strobe
`light of the present invention also requires little mainte-
`nance and generates little electrical noise or heat. Its
`regulated power supply controls available current, sta-
`bilizing the oscillator and light output thereof, and al-
`lowing operation froma camera power supply.
`While a preferred embodiment of the present inven-
`tion has been shown and described, it will be apparent
`to those skilled in the art that many changes and modifi-
`cations may be made without departing from the inven-
`tion in its broader aspects. The appended claims are
`therefore intended to cover all such changes and modi-
`fications as fall within the true spirit and scope of the
`invention.
`T claim:
`1. A light source for providing illumination of an
`object, said light source comprising:
`a diode for emitting light when energized;
`means for periodically energizing said diode with an
`adjustable frequency and duty cycle such that said
`diode emits a sequence oflight flashes illuminating
`said object; and -
`enabling means for selectively enabling and disabling
`said means for periodically energizing said diode,
`ssid enabling means being operatively responsive
`to a synchronization signal.
`z. A light source for providing illumination of an
`object, said light source comprising:
`a diode for emitting light when energized; and
`means for periodically energizing said diode with an
`adjustable frequency and duty cycle such that said
`diode emits a sequence oflight flashes illuminating
`said object;
`
`&
`
`65
`
`5,010,412
`
`6
`wherein said means for periodically energizing said
`diode comprises oscillator means for providing an
`oscillating output signal of adjustable frequency
`and duty cycle with the frequency being adjusted
`_in accordance with a magnitude of an input fre-
`quency control value and the duty cycle being
`adjusted in accordance with the magnitude of an
`input duty cycle control value, means for generat-
`ing a constant supply voltage, and switch means
`operated by said oscillating signal for periodically
`coupling said supply voltage to said diode with a
`frequency and duty cycle determined by the fre-
`quency and duty cycle of the oscillator output
`signal, said supply voltage energizing said diode
`such that said diode emits said light flashes.
`3. A light source for providing monochromatic illum-
`ination of an object photographed by a camera acquir-
`ing an image of the object through a lens, the light
`source comprising:
`a plurality of diodes for emitting light when ener-
`gized;
`means for attaching said diodes to said camera with
`said diodes arranged about said lens and directed
`for illuminating said object, and
`means for periodically energizing said diodes.
`4. The apparatus in accordance with claim 3 wherein
`said camera is adapted to produce a synchronizing sig-
`nal substantially concurrent with operation thereof, and
`including means controlling said energizing means and
`responsive to said synchronizing signal for energizing
`said diode when said camera is acquiring an image.
`§. The apparatus in accordance with claim 3 wherein
`said means for energizing said diodes comprises:
`oscillator means for providing an oscillating output
`signal of predetermined frequency and duty cycle;
`means for providing a supply voltage;
`switch means operated by said oscillating signal for
`periodically coupling said supply voltage to said
`diodes with a frequency and duty cycle determined
`by the frequency and duty cycle of the oscillator
`output signal, said supply energizing said diodes
`such that said diodes concurrently and periodically
`illuminate said object.
`6. A strobe light for providing uniformly intense,
`monochromatic illumination of an object photographed
`by a video camera acquiring a sequence of images of the
`object through a lens and asserting a synchronizing
`signal indicating when it is acquiring an image,
`the
`strobe light comprising:
`a plurality of diodes mounted on the video camera
`generally surrounding the lens, the diodes generat-
`ing light of similar wavelength when energized by
`8 supply source, the intensity of light generated by
`the diodes being determined by a voltage magni-
`tude of said supply source;
`oscillator means responsive to said synchronizing
`signal for providing an output of adjustable fre-
`quency and duty cycle when said synchronizing
`signal indicates said video camera is acquiring an
`image, the frequency being adjusted in accordance
`with a magnitude of an input frequency control
`value, and the duty cycle being adjusted in accor-
`dance with the magnitude of an input duty cycle
`control value;
`means providing a supply source for energizing said
`diodes; an
`switch means operated by said oscillating signal for
`-
`-periodically coupling said supply source to said
`
`Exhibit LG-1005 Page 6
`
`LGELEM0002962
`
`Exhibit LG-1005 Page 6
`
`

`

`10
`
`20
`
`-
`
`45 .
`
`5,010,412
`
`-
`
`8
`7
`the duty cycle being adjusted in accordance with
`diodes with a frequency and duty cycle determined
`the magnitude of an input duty cycle controlvalue;
`by the frequency and duty cycle of the oscillator
`means for generating a constant voltage supply sig-
`output signal to cause diodes simultaneously to
`nal; and
`generate pulses oflight.
`
`7..A strobe light for providing uniformly intense, 5|switch means operated by said oscillating signal for
`monochromaticillumination of an object photographed
`periodically coupling said supply signal
`to said
`by a video camera acquiring a sequence ofimagesofthe
`diodes with a frequency and duty cycle determined
`object,
`the video camera generating a synchronizing
`by the frequency and duty cycle of the oscillator
`signal
`indicating when it
`is acquiring an image,
`the
`output signal, said supply signal energizing said
`strobe light comprising:
`diodes such that said diodes concurrently emit
`@ support having an aperture;
`light.
`a plurality of diodes mounted on said support and
`10. Tho apparatus in accordance with claim 8
`generally surrounding the aperture in a pattern
`wherein said camera comprises a video camera includ-
`providing substantially uniform illumination of the
`ing means
`for generating a synchronizing signal
`object when said support is in juxtaposition with 15 wherein said means for concurrently energizing said
`said object, the diodes generating light of similar|diodes comprises:
`wavelength when energized by a supply signal, the
`oscillator means responsive to said synchronizing
`intensity of light generated by the diodes being
`signal for providing an output signal when said
`determined by a voltage magnitude of the supply
`synchronizing signal indicates said video camerais
`signal,
`acquiring said image;
`means for attaching said support to the camera such
`means for generating a constant voltage supply; and
`that the video camera views the object through the ©
`switch means operated by said oscillating signal for
`aperture as said diodes illuminate said object;
`periodically coupling said supply to said diodes
`oscillator means responsive to said synchronizing
`with a frequency and duty cycle determined by the
`signal for providing an oscillating output signal of 25
`frequency and duty cycle of the oscillator output
`adjustable frequency and duty cycle when said
`signal.
`synchronizing signal indicates said video camerais
`11. A method for illuminating an object photo-
`acquiring an image, the frequency being adjusted in
`graphed by a camera acquiring an image of the object
`accordance with a magnitudeofan input frequency
`through a lens, the method comprising the steps of:
`control value, and the duty cycle being adjusted in 30
`generally surrounding said lens with a plurality of
`accordance with the magnitude of an input duty
`diodes that emit light when energized such that
`cycle control value;
`said light illuminates said object; and
`a voltage source for generating an output voltage
`periodically energizing said diodes.
`signal;
`12. A method for providing monochromatic strobo-
`means for regulating said output voltage signal to 35 scopic illumination of an object photographed by a
`produce a said supply signal of substantially con-
`video camera acquiring a sequence of images of the
`stant voltage;
`object through a lens, the video camera generating a
`switch means operated by said oscillating signal for
`synchronizing signal indicating image acquisition, the
`pericdically applying said supply signal
`to said
`method comprising the steps of:
`diodes with a frequency and duty cycle determined 40
`generally surrounding said lens with a plurality of
`by the frequency and duty cycle of the oscillator
`diodes that emit light when energized by a supply
`output signal, said supply signal causing said diodes
`signal, said diodes being positioned such that their
`to generate light simultaneously;
`emitted light illuminates said object, the intensity
`first means responsive to user input for generating
`of light generated by the diodes being determined
`said frequency control value; and
`by a voltages magnitude of the supply signal;
`second means responsive to user input for generating
`providing an oscillating output signal of predeter-
`said duty cycle control value.
`mined frequency and duty cycle when said syn-
`8. An apparatus for photographing an object, com-
`chronizing signal indicates said video camera is
`prising;
`acquiring an image; and
`acamera for acquiring an image of the object through 50
`applying said supply signal to said diodes in response
`a lens when said objectis illuminated;
`to said oscillating output signal with a frequency
`a plurality of diodes for emitting light when ener-
`and duty cycle determined by the frequency and
`ized;
`duty cycle of the oscillating output signal, said
`means for attaching said diodes to said camera with
`supply signal causing said diodes to generate pulses
`said diodes substantially uniformly distributed 35
`of light.
`about said lens, such that when energized, said
`13. Alight source for providing illumination of an
`diodes illuminate said object with substantially
`object, said light source comprising:
`uniform light intensity; and
`a diode for emitting light when energized;
`means for concurrently energizing said diodes.
`meansfor periodically energizing said diode such that
`9. The apparatus in accordance with claim 8 wherein 60
`said diode emits a sequence of light flashes illumi-
`said means for concurrently energizing said diodes com-
`nating said object; and
`prises:
`enabling meansfor selectively enabling and disabling
`oscillator means for providing an oscillating output
`said means for periodically energizing said diode,
`signal of adjustable frequency and duty cycle, the
`said enabling means being operatively responsive
`frequency being adjusted in accordance with a 65
`to a camera synchronization signal.
`magnitude of an input frequency control value, and
`** #
`#
`4
`
`Exhibit LG-1005 Page 7
`
`LGELEM0002963
`
`Exhibit LG-1005 Page 7
`
`