as) United States
`a2) Patent Application Publication 0) Pub. No.: US 2008/0246532 Al
` COSPERet al. (43) Pub. Date: Oct. 9, 2008
`
`
`
`US 20080246532A1
`
`(54) METHOD FOR CONTROL OVER
`MECHANICAL RESONANT SYSTEM
`
`(76)
`
`Inventors:
`
`James D. COSPER, Goliad, TX
`(US); Enrique Gutierrez, Littleton,
`CO (US)
`
`Correspondence Address:
`MORRISON & FOERSTER LLP
`755 PAGE MILL RD
`PALO ALTO, CA 94304-1018 (US)
`
`(21) Appl. No.:
`
`12/051,735
`
`(22)
`
`Filed:
`
`Mar. 19, 2008
`
`Related U.S. Application Data
`
`(60) Provisional application No. 60/922,711, filed on Apr.
`9, 2007.
`
`Publication Classification
`
`(51)
`
`Int. Cl.
`(2006.01)
`GOSF 1/00
`(52) US. CD. ee cececssseeceserersesesenseesenssensentes 327/518
`57
`ABSTRACT
`67)
`Systems and methodsare provided for automatically driving
`and maintaining oscillation of an assembly system including
`a mass and a bias member (which mayalso bereferred to as
`a spring or elastomeric member) at or near a resonant fre-
`quencyofthe assembly system. In one example, apparatus for
`maintaining oscillation of amoveable subassembly including
`amass and a bias comprises a controller operable to receive a
`signal from a sensor associated with a position or motion of
`the subassembly, and generate a drive signal for driving the
`subassembly in responseto the received signal from the sen-
`sor. In this manner, the controller may monitor the motion of
`the subassembly and adjust or modulatethe driving force over
`time to maintain the subassembly at or near a resonant fre-
`quency. Further, in one example, the subassembly includes a
`resonant engine comprising a movable mirrorofan illumina-
`tion device.
`
`
`
`spring
`
`16
`
`.
`oscillatory
`
`10
`
`ay
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`ontro
` input
`
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`sensor
`
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`feedback
`control
`input
`
`circuit
`
`
`motion
`12
`
` 18
`
`driver output
`force
`
`
`
`Controller
`transducer
`
`
`
`20
`
`1
`
`APPLE 1009
`
`1
`
`APPLE 1009
`
`

`

`Patent Application Publication
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`Oct. 9, 2008 Sheet 1 of 24
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`Patent Application Publication
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`Oct. 9, 2008 Sheet 2 of 24
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`US 2008/0246532 Al
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`
`
`FIG. 1A
`
`
`
`FIG. 1B
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`3
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`

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`Patent Application Publication
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`Oct. 9, 2008 Sheet 3 of 24
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`US 2008/0246532 Al
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`201
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`203
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`FIG. 2A
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`220
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`FIG. 2B
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`

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`Patent Application Publication
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`Oct. 9, 2008 Sheet 4 of 24
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`US 2008/0246532 Al
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`301
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`305
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`307'
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`Top 2 axis parabolic
`reflector Fixed
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`Center. 1 axis parabolic
`reflectorrotates
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`Bottom 2 axis parabolic
`reflector Fixed
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`FIG. 3
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`5
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`

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`Patent Application Publication
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`423
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`Oct. 9, 2008 Sheet 5 of 24
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`Patent Application Publication
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`Oct. 9, 2008 Sheet 6 of 24
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`Patent Application Publication
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`Oct. 9, 2008 Sheet 7 of 24
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`US 2008/0246532 Al
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`507
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`FIG. 6
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`8
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`Patent Application Publication
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`Oct. 9, 2008 Sheet 8 of 24
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`US 2008/0246532 Al
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`Parabolic reflector
`
`round rear surface
`
`FIG. 7
`
`9
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`

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`Patent Application Publication
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`Oct. 9, 2008 Sheet 9 of 24
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`US 2008/0246532 Al
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`10
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`Patent Application Publication
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`Oct. 9, 2008 Sheet 10 of 24
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`US 2008/0246532 Al
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`FIG. 9A
`
`st
`
`of
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`
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`
`Light(S) ferry} Mirror
`
`
`Housing
`subassembly
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`907
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`903
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`11
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`11
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`

`

`Patent Application Publication
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`Oct. 9, 2008 Sheet 11 of 24
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`US 2008/0246532 Al
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`FIG. 10
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`1001
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`12
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`12
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`

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`Patent Application Publication
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`Oct. 9, 2008 Sheet 12 of 24
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`US 2008/0246532 Al
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`1105
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`FIG. 11A
`
`FIG. 11B
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`1101
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`FIG. 11C
`
`13
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`13
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`

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`Patent Application Publication
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`Oct. 9, 2008 Sheet 13 of 24
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`US 2008/0246532 Al
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`FIG. 12A
`FIG. 12B
`
`14
`
`14
`
`

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`Patent Application Publication
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`Oct. 9, 2008 Sheet 14 of 24
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`US 2008/0246532 Al
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`FIG. 13A
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`FIG. 13B
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`FIG. 13C
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`Patent Application Publication
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`Oct. 9, 2008 Sheet 15 of 24
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`Patent Application Publication
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`Patent Application Publication
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`Oct. 9, 2008 Sheet 17 of 24
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`US 2008/0246532 Al
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`FIG, 16A
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`FIG. 16B
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`Patent Application Publication
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`Oct. 9, 2008 Sheet 18 of 24
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`US 2008/0246532 Al
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`FIG. 17A
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`FIG. 17B
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`FIG. 17E
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`MINUS 11.25
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`FIG. 17F
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`

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`Patent Application Publication
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`Oct. 9, 2008 Sheet 19 of 24
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`US 2008/0246532 Al
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`/ 1801
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`FIG.18A
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`FIG. 18B
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`FIG. 18C
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`

`

`Patent Application Publication
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`Oct. 9, 2008 Sheet 20 of 24
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`US 2008/0246532 Al
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`FIG, 19A
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`FIG. 19B
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`Patent Application Publication
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`Oct. 9, 2008 Sheet 21 of 24
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`US 2008/0246532 Al
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`2001
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`FIG. 20A
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`Patent Application Publication
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`Oct. 9, 2008 Sheet 22 of 24
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`US 2008/0246532 Al
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`FIG. 21A
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`Patent Application Publication
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`Oct. 9, 2008 Sheet 23 of 24
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`US 2008/0246532 Al
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`FIG. 22A
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`Patent Application Publication
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`Oct. 9, 2008 Sheet 24 of 24
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`US 2008/0246532 Al
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`FIG. 23A
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`FIG. 23B
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`US 2008/0246532 Al
`
`Oct. 9, 2008
`
`METHOD FOR CONTROL OVER
`MECHANICAL RESONANT SYSTEM
`
`tracked by a controller, so that the mechanical resonant sys-
`tem is driven and continues to oscillate at the new resonant
`
`CROSS-REFERENCE TO RELATED
`APPLICATIONS
`
`
`
`BRIEF SUMMARY
`
`frequency.
`
`[0001] This patent claims priority to U.S. Provisional
`Patent application No. 60/922,711, entitled “METHOD FOR
`CONTROL OVER MECHANICAL RESONANT SYS-
`
`TEM,”filed Apr. 9, 2007, which is hereby incorporated herein
`by referencein its entirety for all purposes. This applicationis
`further relatedto previously filed U.S. patent application Ser.
`No. 11/665,109, entitled “DEVICES AND METHODS FOR
`EFFICIENT RESONANT,”filed on Apr. 10, 2007, and U.S.
`provisional patent application Ser. No. 60/922,711, entitled
`“METHOD FOR CONTROL OVER MECHANICAL
`
`RESONANT SYSTEM,”filed on Apr. 9, 2007, both ofwhich
`are incorporatedherein byreferenceintheir entirety as iffully
`set
`forth herein.
`
`
`
`BACKGROUND
`
`1. Field
`[0002]
`[0003] This application generally relates to systems and
`methods for control of a mass andbias (e.g., “elastomeric
`members”) subassembly, including oscillating mechanical
`systems, that operate in an oscillatory modeat or neartheir
`mechanical resonant frequency. In one example, the systems
`are described for use with illumination systems including an
`oscillating resonant engine.
`[0004]
`2. Related Art
`[0005] Mechanical systems typically have a resonant fre-
`quency, a natural frequency at which the system tends to
`moveor oscillate when an impulse is applied. Moving the
`system at non-resonant frequencies may require significantly
`more energy. Accordingly, it may be desirable to move and
`control a mechanical system at or near its resonant frequency
`to achieve the maximum system movementfor a reduced or
`minimal amountof energy.
`[0006] The resonant frequency of a mechanical system
`tends to vary over time, with changes in mass, mechanical or
`elastomeric properties, ageing, friction, wear or dampening
`to namebut a few. Maintaining a mechanical system moving
`at its resonant frequency requires significantly less energy,
`but may involve greater complexity.
`[0007] Driving a mechanical resonant system for low loss,
`and a high Q, at or near its resonant frequency using an
`external frequency references may require a highly stable
`frequency source. It may also require that the resonantfre-
`quency of the mass and spring mechanism itself be very
`stable. The frequency of the two systems, one mechanical,
`and one electronic, will typically drift apart over time. Even
`relatively small variations in frequency between the two sys-
`tems may cause the amplitude of the mechanicaloscillations
`to decrease significantly.
`[0008] Accordingly,
`it may be desirable to incorporate
`feedback into such systems to eliminate the need for a sec-
`ondary (external) frequency source such that the naturalfre-
`quency of the mechanical resonant system becomesthe fre-
`quency reference. Any variation in the mechanical resonant
`system that affects its resonant frequency is sensed and
`
`[0009] The present invention discloses systems and meth-
`ods
`for automatically driving (e.g., controlling energy
`applied) and maintaining oscillation ofan assembly including
`a mass and a bias member (which mayalso bereferred to as
`a spring or elastomeric member) at a resonant frequency. In
`one example, apparatus for maintaining oscillation of a
`moveable subassembly including a mass and bias comprises
`a controller operable to receive a signal from a sensor asso-
`ciated with a position or motion of the subassembly, and
`generate a drive signal for driving the subassembly in
`response to the received signal from the sensor. In this man-
`ner, the controller may monitor the motion of the subassem-
`bly and adjust or modulate the driving force over time to
`maintain the subassemblyat or near resonant frequency. Fur-
`ther, in one example, the subassembly includes a resonant
`engine comprising a mirror of an illumination device.
`[0010] The mass and bias may include any movable assem-
`bly having a resonant frequency (or frequencies). In some
`variations the subassemblyis securedto a relatively immobile
`(or fixed) structure (such as a housing) and the assembly of
`the mass and bias moves with respect to the structure. The
`control systems described herein may be embodiedas control
`circuits or drive circuits of a controller. A drive circuit typi-
`cally functions to compensate for changes in mechanical,
`electrical or magnetic parameters that may otherwisealter the
`mechanism’s resonant frequency. In general, a mass may be
`set in motion via an electromagnetic control and drive circuit.
`Feedback on the position, velocity, and/or acceleration of the
`mass maybe input to the controller. The controlleris operable
`to process the feedback signal and generate drive signals that
`are processed to maintain mechanical oscillation at
`the
`mechanical resonant frequency of the system.
`[0011] A drive circuit, incorporated with the controller or
`separate thereto, may function such that it maintains the
`amplitude of oscillation of the subassembly at a desired
`amplitude set-point. The drive circuit may allow for an ampli-
`tude set-point input for oscillation amplitude adjustability.
`The drive circuit may function to compensate for mechanical,
`electrical or magnetic parameter changes that may tend to
`alter the mechanism’s oscillation amplitude set-point. A drive
`circuit may function such that it can vary the resonantfre-
`quency of a mass and spring mechanism byaltering the sys-
`tem’s restoring force electromagnetically (or via other appro-
`priate means). A drive circuit may function such that it can
`automatically maintain the resonant frequency of a mass and
`spring mechanism at a desired frequency set-point.
`[0012] Any appropriate subassembly maybe used with the
`systems and methods described herein. For example, a con-
`troller (including a control circuit) as described herein may be
`used to control or regulate the oscillation of a device for
`resonantillumination. Thus, in one example described herein,
`a control system as described herein may be used to control
`oscillation of a mirror subassembly forefficient illumination.
`[0013] The details of one or more embodiments of these
`control systems, assembly systems,
`illumination systems,
`and/or methods of using them are set forth in the accompa-
`nying drawing and in the description below. Other features,
`
`26
`
`26
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`

`

`US 2008/0246532 Al
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`Oct. 9, 2008
`
`objects, and advantagesof the inventions will become appar-
`ent from the description and drawings, and from the claims.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`[0014] The accompanying drawings, which are incorpo-
`rated in and form a part of this specification,
`illustrate
`embodiments of the invention and, together with the descrip-
`tion, serve to explain the principles of the invention:
`[0015]
`FIG. 1 is a schematicillustration of an exemplary
`control system and subassembly systemsas described herein.
`[0016] FIG.1A showsan illumination pattern of a typically
`static device. FIG. 1B showsan illumination pattern for a
`device in which the light from the light source is scanned as
`described herein.
`
`FIGS. 2A and 2B show schematic cross-sections
`[0017]
`through a variation of an illumination device as described
`herein
`FIG. 3 shows one arrangementif a resonant illumi-
`[0018]
`nation system in which multiple mirrors are used.
`[0019]
`FIG. 4 shows an exploded three-dimensional view
`of an illumination device as described herein.
`
`FIGS. 20A-20Billustrate the operation of a reso-
`[0040]
`nant engine such as the resonant engine shown in FIGS.
`19A-19B.
`
`FIGS. 21A and 21B show top andside perspective
`[0041]
`views, respectively, of a mirror that may be used as part of a
`resonant engine.
`[0042]
`FIG. 21C illustrates a reflection pattern for the mir-
`ror shownin FIGS, 21A-21B.
`
`FIGS. 22A and 22B show top andside perspective
`[0043]
`views, respectively, of a mirror that may be used as part of a
`resonant engine.
`[0044]
`FIG. 22C illustrates a reflection pattern for the mir-
`ror shown in FIGS. 21A-21B.
`
`FIGS. 23A and 23B show top andside perspective
`[0045]
`views, respectively, of a mirror that may be used as part of a
`resonant engine.
`[0046]
`FIGS. 24A and 24B showtop andside perspective
`views, respectively, of a mirror that may be used as part of a
`resonant engine.
`
`DETAILED DESCRIPTION
`
`FIG. 6 showsa partial cross-sectional view of an
`[0021]
`illumination device similar to that shown in FIGS. 4 and5.
`
`[0022] FIG.7 showsa schematic of an illumination device
`having an elongatedlight source (e.g., bulb) and a mirror with
`a parabolic reflective surface reflecting light from the light
`source, as described herein.
`[0023]
`FIGS. 8A and 8Billustrate another variation of an
`illumination device as described herein.
`
`FIGS. 13A-13D show schematic illustrations of
`[0029]
`components of a resonant engine, similar to that shown in
`FIG. 10.
`
`[0047] The following description is presented to enable a
`[0020] FIG.5illustrates a cross-section through the middle
`
`ofan illumination device similar to the one shownin FIG.4.
`person of ordinary skill in the art to make and use the inven-
`tions. Descriptions of specific materials,
`techniques, and
`applications are provided only as examples. Various modifi-
`calions to the examples described herein will be readily
`apparent to those of ordinary skill in the art, and the general
`principles defined herein may be applied to other examples
`and applications without departing from the spirit and scope
`ofthe invention. Thus,the present invention is not intended to
`be limited to the examples described and shown, but is to be
`accorded a scope consistent with the appended claims.
`FIG. 9A showsa block diagram ofone variation of
`[0024]
`[0048] Exemplary systems and methods described herein
`a resonant engine.
`may include a mass and spring mechanism (subassembly),
`[0025]
`FIG. 9B shows a schematic of a resonant engine
`including one or more mass member(s), where the massis a
`system.
`part of the mechanism which will oscillate when driven. The
`FIG. 10 is one variation of a resonant engine.
`[0026]
`subassembly further including one or more elastomeric mem-
`FIGS. 11A-11C show one variation of a bias, con-
`[0027]
`ber(s); for example, a spring, an electrometric band,a plastic
`figured as a clock spring.
`member, a rubber member, a metal member, a composite
`[0028] FIGS.12A-12B showaclockspring to which arotor
`member, a clock spring,or the like. The subassembly further
`is attached.
`including a meansofattaching the elastomeric memberto the
`mass member, a volume, which maybepartially or com-
`pletely enclosed (e.g., within a housing) to allow for a range
`of motion for the mass to oscillate (for example, in a one
`dimensionallinear or rotational mode of movement; in a two
`dimensional planer or rotational mode of movement; or in a
`three dimensional volumeor rotational mode of movement).
`In one particular example provided herein, the mass includes
`an oscillating mirror assembly.
`[0049]
`FIG.1 illustrates schematically an exemplary con-
`trol system 10 for use with a mechanical resonant subassem-
`bly system.In general, the control system 10 described herein
`includes controllogic (e.g., hardware, software, firmware, or
`combinations thereof included with a controller or control
`circuit 12), a sensor 14 for determining a parameter from the
`moveable subassembly (e.g., including a bias 16 and mass
`18), a sensor input for inputting the parameterinto the control
`logic of control circuit 12, and a control output from the
`control logic to drive the moveable subassembly at or near
`resonance via force transducer 20.
`
`[0030] EIGS. 144-14C show perspective, top and side cut-
`away views, respectively, of a portion of a resonant engine.
`[0031]
`FIGS. 15A-15Cis another variation of a resonant
`engine.
`FIG. 16A is one example of a profile of mirror for
`[0032]
`use with a resonant engine.
`[0033]
`FIGS. 16B-16D illustrate scanning of the mirror
`shown in FIG. 16A.
`
`FIG. 17A is one example of a profile of mirror for
`[0034]
`use with a resonant engine.
`[0035]
`FIGS. 17B-17F illustrate scanning of the mirror
`shown in FIG. 16A.
`
`FIG. 18A is one example of a profile of mirror for
`[0036]
`use with a resonant engine.
`[0037]
`FIGS. 18B-18F illustrate scanning of the mirror
`shown in FIG. 16A.
`
`FIGS. 19A-19B illustrate another variation of a
`[0038]
`resonant engine.
`[0039] FIG.19C isan exemplary drive signal for a resonant
`engine as shown in FIG. 19A-19B.
`
`[0050] The control logic may be contained within a con-
`troller or control circuit 12, and may include one or more
`feedback inputs from one or more sensors 14. Any appropri-
`ate sensor may be used(e.g., optical, magnetic, capacitive,
`
`27
`
`27
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`

`

`US 2008/0246532 Al
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`Oct. 9, 2008
`
`etc.), and may detect any appropriate parameter that may
`correlate the position of the subassembly (e.g., from which
`the motion ofthe subassembly maybe derived). For example,
`one or more sensors 14 may detect position, velocity, accel-
`eration,etc. for the subassembly(e.g., of bias 16 and/or mass
`18). In some variations, a sensor 14 is connectedto a driver
`associated with force transducer 20, and senses the load or
`driving force applied to the subassembly. Sensors 14 may
`include electrical sensors, electromagnetic sensors, optical
`sensors, induction sensors, photosensors, or the like (classes
`of sensors may include: induction, electrical, photo, optical,
`electromagnetic, motion, ultrasonic, infrared, etc.).
`[0051] The output from the control logic of control circuit
`12 may output (and thus control) a force transducer 20 for
`applying force directly or indirectly to mass 18. Examples of
`force transducers include, but are not limited to: motors,
`electromagnetic drivers (e.g.,
`reciprocal electromagnetic
`drivers), a voice coil motor, a piezoelectric driver, a solenoid
`(including a linear solenoid), a menetostrictive driver, a
`MEMSdriver, and the like. The driver is typically matched to
`the subassembly. For example, if the subassembly includes a
`magnet, the driver may include an electromagnetic source
`that applies amagnetic field to act on the magnet(as described
`with respect to various examples provided herein).
`[0052]
`In operation, control circuit 12 receives one or more
`inputs on the position or motion (or both) of the subassembly,
`and is operable to output signalsto the force transducer 20 for
`driving the subassembly. In somevariations, the control logic
`also receives input from the force transducer 20, for example,
`indicating the status or load under whichthedriver is operat-
`ing, and which maybe used for adjusting output signals to
`force transducer 20 over time.
`
`[0053] The subassembly (bias 16 and mass 18) may be
`separate from control system 10 or may be included with the
`system, for example, in a common housingor included with
`a commonbase. In addition, control system 10 may include
`one or more control inputs for controlling the power to the
`control logic/control circuit 12. For example, control system
`10 may include an on/off switch, a control for increasing the
`oscillationrate (e.g., the resonant frequencyor increasing to a
`newresonant frequency), or any other appropriate control.
`[0054]
`Inone example, control circuit 12 comprises control
`logic that may include sensorinput conditioning and process-
`ing logic, signal phase compensation logic, force transducer
`driver logic for one or more force transducers, one or more
`force transducer driver power controls, as well as other well
`known components for receiving feedback signals and out-
`putting drive signals. In operation, and according to one
`example, control circuit 12 operates to (1) initiate movement
`of the subassembly, (2) determine an energy-efficient reso-
`nant frequency for operation of the system, and (3) maintain
`operation of the system at a resonant frequency. In addition,
`the system may also be adjusted to modify the resonant fre-
`quency, or identify another resonant frequency (harmonic) at
`a faster or loweroscillationrate.
`
`In one example, control circuit 12 operates to main-
`[0055]
`tain the amplitude of oscillation of the subassembly at a
`desired amplitude set-point. Further, control circuit 12 may
`further allow for an amplitude set-point input for oscillation
`amplitude adjustability. In this manner, control circuit 12 may
`function to compensate for mechanical, electrical, and/or
`magnetic parameter changesthat maytendto alter the mecha-
`nism’s oscillation amplitude set-point. In operation, control
`circuit 12 may operate to vary the resonant frequency of a
`
`massand spring mechanism byaltering the system’s restoring
`force electromagnetically (or via other appropriate means).
`Accordingly, control circuit 12 may function to automatically
`maintain the resonant frequency of a mass and bias subas-
`sembly at a desired frequency set-point.
`[0056]
`Implementation of the described methods and
`operations may be carried out via software, hardware, firm-
`ware, or any suitable combination thereof. Further, one of
`ordinary skill in theart will recognize that various algorithms
`for analyzing feedback signals and driving the resonant sub-
`assembly as described are contemplated.
`[0057] Any appropriate subassembly maybe used with the
`systems and methods described herein. For example, a con-
`troller, including a control circuit, as described herein may be
`used to control or regulate the oscillation of a device for
`resonant
`illumination. One exemplary application of the
`described control system is with an oscillating mirror system
`that may be used with a light source to provide illumination
`that is highly effective, and may be energy efficient. For
`example, an illumination systemthat oscillates one or more
`mirrors to light a broad region while operating at or near a
`resonant frequencyor its harmonic. Such devices, systems,
`and methods are often referred to as “resonant engines,”
`“resonant
`lighting,’ or “resonant engines for adjustable
`light.” Thus the systems maybereferred to as “R.E.A.L”
`systems (“resonant engines for adjustable light” systems) or
`resonant engine systems. The systemsare further described,
`for example, in copending U.S. patent application Ser. No.
`11/665,109, entitled “DEVICES AND METHODS FOR
`EFFICIENT RESONANT,’filed on Apr. 10, 2007, and U.S.
`provisional patent application Ser. No. 61/028,460, entitled
`“DEVICES AND METHODS FOR GENERATING BEAM
`PATTERNS WITH CONTROLLABLE INTENSITY,
`COLOR OR INFORMATION CONTENT,”filed on Feb. 13,
`2008, both of which are hereby incorporated by reference in
`their entirety as if fully set forth herein.
`[0058]
`In general,
`the resonant
`illumination devices
`described herein include a mirror (or multiple mirrors)
`mounted to a bias. The mirror and bias may form a mirror
`subassemblythatis attached to an engine support (e.g., hous-
`ing). The mirror subassembly may include additional com-
`ponents(e.g., arotor or other portion ofthe mirrordriver), and
`is typically mountedsothat it may be moved(e.g., oscillated)
`in a substantially undamped fashion continuously at or near
`the resonant frequency ofthe mirror subassembly. The mirror
`subassembly may be a single (unitary) component. For
`example, the mirror and subassembly may be the same com-
`ponent. The devices may also include a mirror driver that
`provides force to load and unload the bias and move the
`mirror(s). The mirror driver may also be mounted to the
`support. The mirror driver may be configured to provide force
`to move the mirror (or mirror subassembly) at or near a
`resonant frequency of the mirror and bias combination. In
`some variations one or more control circuits is included to
`control the force applied by the mirrordriver so that the mirror
`and bias are moved at or near a resonant frequency and the
`desired magnitudefor the mirror andbias. In somevariations,
`one or more sensor(s) may provide inputto the control circuit.
`[0059] A light source mayalso be included,eitheras part of
`the resonant engine, or as part of a system including the
`resonant engine. Light from the light source maybereflected
`by the resonant engine to form a pattern as the resonant engine
`movesthe mirror. The emissions of the light source (orillu-
`mination source) are typically guided by the mirror, which
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`US 2008/0246532 Al
`
`Oct. 9, 2008
`
`movesin an energy-efficient mechanically resonant fashion,
`directing the emitted light toward a target or in a desired
`direction, creating an illumination pattern. This larger illumi-
`nation pattern is formed by the rapid movement of smaller
`discrete spots, bars or other shapes of illumination, but will
`typically be seen by an observeras illumination ofthe entire
`largerarea, and as equivalent to the illumination generated by
`a higher power illumination source directed over the same
`area.
`
`as including a “housing” may instead(or in addition) include
`the more general “engine support.”
`[0065] The devices described herein typically include a
`mirror and may be used with (or may include)a light source.
`In most variations,
`the light source does not move with
`respectto the mirror, while the mirror is capable ofmovingat
`a resonant frequency. Resonanceis the tendency of a system
`to absorb more energy whenthe frequency ofits motion(e.g.,
`oscillation or vibration) matches the system’s natural fre-
`[0060] The following description is presented to enable any
`quency ofvibration (its resonant frequency) than it does at
`person of ordinary skill in the art to make and use the inven-
`other frequencies. The resonant frequency of the mirror and
`tion. Descriptions of specific materials,
`techniques, and
`bias may be determined based on the materials used to form
`applications are provided only as examples. Various modifi-
`them, and their arrangement, and maybecalculated ordeter-
`cations to the examples described herein will be readily
`mined experimentally. There is usually a “family” ofresonant
`apparentto those of ordinary skill in the art, and the general
`frequencies for the mechanical system of the illumination
`principles defined herein may be applied to other examples
`device (e.g., harmonics). In general, the illumination devices
`and applications without departing from the spirit and scope
`described herein may movethe mirrorat a resonantfrequency
`ofthe invention. Thus, the present invention 1s not intended to
`that is greater than the average threshold for detection of
`be limited to the examples described and shown,butis to be
`“flickering”by the unaided human eye. For example, atypical
`accorded a scope consistent with the appendedclaims.
`eye can detect flickering (temporal separation) of an equal
`intensity light source at intervals as low as 15-25 ms(e.g.,
`[0061] As used herein, the term “mirror” mayrefer to any
`app. 40-60 Hz).
`appropriate reflective surface. A mirror may beaflat or sub-
`stantially flat reflective surface, or a curved,elliptical, para-
`[0066] Thus, in some variations, it may be desirable to
`bolic, rounded, off-axis, bent or facetted surface. In some
`configure the device to operate at a resonant frequencythat is
`variations, the mirroris only partially or selectively reflective.
`greater than (or equal to) the threshold for detection of
`The mirror may be a compound mirror, and may have mul-
`“flicker” so that the area illuminated by the illumination
`tiple facets or faces. Examples and further descriptions of
`device appears as solid to an observer. The resonant fre-
`mirrors are provided below.
`quencyat which the device operates may be determined based
`onthe intended use for the device or the environmentin which
`[0062] As used herein, the term “bias” may refer to any
`the device operates. For example, a handheld device may
`appropriate element to which maybedisplaceable, flexible,
`and/orelastic. Typically, a bias may store mechanical energy
`typically be operated at a resonant frequency between about
`
`during loading whenit is moved fromafirst position, and then 10 to 60 Hz (e.g., approximately 40 Hz). A fixed illumination
`release the mechanical energy during unloading when it
`device (e.g., a non-handheld device) may be operated at a
`returns towards the first position. A bias may be an elastic
`slightly higher resonant frequency, e.g., between about 60 and
`material or a structure having elastic properties (e.g., elastic-
`120 Hz. (e.g., approximately 72 Hz). As described below,the
`ity or resilience). For example, a bias may be selected from
`operational (e.g., resonant) frequency may be configured
`the group consisting of: a spring, an electrometric band, a
`based on the power source (e.g., AC current), and may be
`string, a plastic member, a rubber member, a metal member,
`adjusted by adding spring components, dampening compo-
`and a composite member. Oneparticular exampleofa biasis
`nents, or other modifying elements.
`a clock spring.
`[0067]
`FIGS. 1A and1B illustrate a proof-of principle of a
`[0063] As used herein, the term “light source” mayrefers to
`device as described herein. In FIG. 1A a light source having a
`any appropriate source of light, particularly electrically-acti-
`circular beam pattern (a spot) is projected directly on a target
`vated light sources such as lamps, light bulbs, LEDs, coherent
`surface, shown as a calibrated wall. The beam pattern has a
`light sources, flash lamps, etc. The devices described herein
`diameter 101 thatis fixed by the optics of the light source.In
`mayalso be referredto aslightor lighting devices, and may be
`FIG. 1B the samelight source is used in conjunction with a
`
`part of an illumination system or light system. The resonant resonant engine (not shown) having a mirror andabias, anda
`mirror driver that oscillates the mirror at or near a resonant
`engine devices described herein may be fixed or mounted
`(e.g., configured to be attached to a surface or object), or they
`frequency of the mirror and bias. The spot is projected onto
`may be hand-held devices, and may be used in any application
`the moving mirror. The mirroris oscillating abounda neutral
`in which illumination would be useful, particularly in appli-
`position (e.g., 0°) through a positive and negative angle of
`cations in which low-power, wide-range illumination would
`deflection, which may be based onthe bias (e.g., 45°). As a
`be useful.
`result, the spot of light from the light source is effectively
`scanned overthe target. The frequency of oscillation of the
`beam of light (for this single mirror example) is equivalentto
`the frequency of light of the oscillation of the mirror. The
`result is a perceived illumination pattern on the target that is a
`field ofview having a muchlarger diameter 103 thanthe static
`spot 101 shown in FIG. 1A. The mirror and bias (or mirror
`subsystem) may be movedin a very energy-efficient manner
`by driving them at or near resonance.
`[0068] FIG.9A showsa block diagram describingthe rela-
`tionship between someof the elements that may be included
`in the resonant engine devices and systems f