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WO2008095081A2 - Marqueurs comportant des nanocristaux semi-conducteurs d'émission de lumière et leur utilisation - Google Patents

Marqueurs comportant des nanocristaux semi-conducteurs d'émission de lumière et leur utilisation Download PDF

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Publication number
WO2008095081A2
WO2008095081A2 PCT/US2008/052620 US2008052620W WO2008095081A2 WO 2008095081 A2 WO2008095081 A2 WO 2008095081A2 US 2008052620 W US2008052620 W US 2008052620W WO 2008095081 A2 WO2008095081 A2 WO 2008095081A2
Authority
WO
WIPO (PCT)
Prior art keywords
semiconductor nanocrystals
marker
semiconductors
wavelength
peak emission
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US2008/052620
Other languages
English (en)
Other versions
WO2008095081A3 (fr
Inventor
San Ming Yang
Luis A. Sanchez
James C.M. Hayes
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Evident Technologies Inc
Original Assignee
Evident Technologies Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Evident Technologies Inc filed Critical Evident Technologies Inc
Publication of WO2008095081A2 publication Critical patent/WO2008095081A2/fr
Publication of WO2008095081A3 publication Critical patent/WO2008095081A3/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S1/00—Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmitters; Receivers co-operating therewith
    • G01S1/70—Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmitters; Receivers co-operating therewith using electromagnetic waves other than radio waves
    • G01S1/703—Details
    • G01S1/7032—Transmitters
    • G01S1/7034—Mounting or deployment thereof
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
    • G01S5/16—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using electromagnetic waves other than radio waves

Definitions

  • the present invention relates generally to markers for motion tracking and to a system which is capable of optically monitoring and recording full or partial object movements and, more particularly, to markers comprising semiconductor nanocrystal complexes.
  • the present invention also relates to methods of formulating liquid inks containing semiconductor nanocrystals for the preparation of such markers.
  • Semiconductor nanocrystals are crystals typically made of M-Vl, Ml-V, IV-VI, or ll-alloyed I-IM-VI materials (e.g., CdSe, CdS, CdTe, CnS, ZnSe, PbS, PbSe, PbTe, CuInGaS, CuInGaSe, ZnCuInGaS, ZnCuInGaSe, InP, or InGaP) that have a diameter between about 1 nanometer (nm) and about 20 nm.
  • the physical diameter of the nanocrystals is smaller than the bulk excitation Bohr radius, causing quantum confinement effects to predominate.
  • the nanocrystal is a 0-dimensional system that has both quantized density and energy of electronic states where the actual energy and energy differences between electronic states are a function of both the nanocrystal composition and physical size. Larger nanocrystals have more closely spaced energy states and smaller nanocrystals have the reverse. Because interaction of light and matter is determined by the density and energy of electronic states, many of the optical and electric properties of nanocrystals can be tuned or altered simply by changing the nanocrystal geometry (i.e., physical size).
  • Nanocrystals or populations of nanocrystals exhibit unique optical properties that are size tunable. Both the onset of absorption and the photoluminescent wavelength are a function of nanocrystal size and composition. The nanocrystals will absorb all wavelengths shorter than the absorption onset; however, photoluminescence will always occur at the absorption onset. The bandwidth of the photoluminescent spectra is due to both homogeneous and inhomogeneous broadening mechanisms. Homogeneous mechanisms include temperature- dependent Doppler broadening and broadening due to the Heisenberg uncertainty principle, while inhomogeneous broadening is due to the size distribution of the nanocrystals.
  • Triangulation is described in numerous systems for measuring object surface or point locations.
  • a typical system sends a beam of collimated light onto an object and forms images of that light through a sensor.
  • the parallax displacement along the axis between the projector and the sensor is used to compute a range to the illuminated point.
  • This type of system is exemplified in US Patent Nos. 5,198,877 to Schulz, RE35,816 to Schulz, 5,828,770 to Leis et al., 5,622,170 to Shulz, and 6,801 ,637 to Voronka.
  • Known target locating systems are used to track specific body points for medical purposes or to provide the means to capture an object's surface points for the purpose of three-dimensional digitization of object geometry.
  • targets are either projected from scanned, collimated light sources or are active light-emitting markers affixed to the object that is being tracked.
  • Some known systems utilize linear CCD sensors that capture light through cylindrical lens systems. Some utilize more than one active emitter, where multiple emitters are distinguished from each other through geometrical marker identification (not time multiplexing).
  • Some known systems describe a tag or marker controller that is synchronized with the imaging sensor systems.
  • the invention relates to markers comprising emissive semiconductor nanocrystals, where the markers are used in an optical system capable of tracking the motion of an object, including the human body or portions thereof.
  • a system according to the invention provides a simultaneous measurement of multiple photoluminescent markers, preferably attached to an object or person to be tracked, the markers having the same or different emission wavelength bands.
  • Markers according to the invention are illuminated with a short wavelength light source and emit light in specific wavelength bands within the spectrum where the peak emission wavelength is a function of composition and diameters of the nanocrystals in the marker.
  • short wavelength light sources include, for example, ultraviolet lamps (mercury vapor, xenon flashlamps, deuterium lamps), light emitting diodes (blue, violet, UV), and excimer lasers.
  • Other light sources having a peak emission wavelength less than the peak emission wavelength of the nanocrystals of the marker may also be employed.
  • An optical system according to the invention may include one or more imaging devices having an optical filtering apparatus for discriminating between individual markers. Such a system may be used to track the spatio-temporal location of each marker by triangulation and data processing.
  • each marker (identifying an object or a portion of an object) has a different emission wavelength(s).
  • each object may be decorated with a plurality of markers, each of the same wavelength, with different objects being decorated with a plurality of markers of different wavelengths. Because each marker has a unique emission wavelength, multiple objects can be tracked simultaneously via an imaging system having optical filters capable of distinguishing the different wavelengths emitted by individual markers or sets of markers. Unlike known tracking systems, a system according to the invention does not require temporal synchronization of the emitters and detectors.
  • nanocrystals are prepared as an ink.
  • a marker is constructed by printing the nanocrystal ink onto a substrate in a specific spatial pattern.
  • a tracking system comprising one or more imaging devices can discriminate between markers or sets of markers by identifying both unique emission wavelengths as well as unique spatial patterns.
  • a first aspect of the invention provides a system for tracking an object, the system comprising: at least one marker capable of fixation to an object to be tracked, the at least one marker including semiconductor nanocrystals having a peak emission wavelength; an illuminating system for exciting the semiconductor nanocrystals of the at least one marker, the illuminating system being capable of transmitting a wavelength shorter than the peak emission wavelength of the semiconductor nanocrystals; and an imaging system for imaging a wavelength emitted by the semiconductor nanocrystals.
  • a second aspect of the invention provides a marker comprising: a substrate; and semiconductor nanocrystals on a surface of the substrate, wherein the semiconductor nanocrystals emit light at a peak emission wavelength in response to excitation by a wavelength shorter than the peak emission wavelength.
  • a third aspect of the invention provides a method of tracking an object, the method comprising: affixing to the object at least one marker, the at least one marker including semiconductor nanocrystals capable of emitting light at a peak emission wavelength in response to excitation by a wavelength shorter than the peak emission wavelength; exciting the semiconductor nanocrystals with a wavelength shorter than the peak emission wavelength; imaging the wavelength emitted by the semiconductor nanocrystals using an imaging device; and tracking the object based on a change in spatiotemporal position of the wavelength emitted by the semiconductor nanocrystals.
  • FIG. 1 shows an illustrative tracking system according to an embodiment of the invention
  • FIG. 2 shows absorption and emission (525 nm) spectra of illustrative semiconductor nanocrystals according to the invention
  • FIG. 3 shows illustrative spatial patterns suitable for use with ink-based semiconductor nanocrystals
  • FIG. 4 shows an absorption spectrum of a color filter manufactured by Gamcolor Inc., suitable for use in a camera for resolution enhancement.
  • FIG. 1 shows a general schematic of a semiconductor nanocrystal tracking system according to an embodiment of the invention.
  • the present invention provides for a motion tracking system 10.
  • An illuminating source 20 emits light with a wavelength(s) less than the peak emission wavelength of the nanocrystals 25 of the marker 30.
  • the illuminating source may be a short wavelength light source, such as a filtered or unfiltered UV lamp (mercury vapor, xenon, deuterium), blue, violet, or UV LED or LED array, excimer laser, solid state laser, or similar device.
  • Semiconductor nanocrystals 25 are applied to a surface of the marker 30, which is attached to a movable object 40.
  • the movable object 40 is illuminated by illuminating source 20.
  • Light emitted from the marker 30 is recorded by one or more imaging system 50 with one or more optical filters 60. Imaging data are sent to a computer 70 and the spatiotemporal position of the marker 30 is calculated and displayed using digital video software.
  • Light from the illuminating source 20 may be long UV (about 350 nm to about 385 nm), violet (about 405 nm to about 410 nm), or blue (about 440 nm to about 470 nm).
  • nanocrystals have broadband absorption spectra and can therefore be excited by any light having a wavelength shorter than the peak emission wavelength of the nanocrystals.
  • semiconductor nanocrystals may be excited by wavelengths that are less than the emission wavelengths of the semiconductor nanocrystal, as illustrated in FIG. 2.
  • Different markers 30 may emit distinct colors, the emitted color being dependent on the size of the semiconductor nanocrystal. Emission from the marker 30 is then recorded by a plurality of imaging devices of the imaging system 50.
  • imaging devices include digital cameras (e.g., CCD or CMOS focal plane array cameras) and imaging devices using film.
  • markers having semiconductor nanocrystals with different emission wavelengths are used to discriminate among multiple objects or between multiple parts of one or more objects. Tracking the spatiotemporal location of each marker permits the tracking of each object or each part of the object(s).
  • semiconductor nanocrystals are formulated in the form of inkjet ink and used to print a spatial pattern on the marker, such as the patterns shown in FIG. 3.
  • semiconductor nanocrystals may be formulated in the form of flexographic ink, screen printing ink, or a thermal transfer ribbon. Other forms for printing spatial patterns are also possible and within the scope of the invention.
  • the object or objects to be tracked may be, for example, a person or an appendage of a person or persons. Such persons may be located in an immersive environment, such as a movie studio, where there are ambient lighting conditions.
  • the tracked person(s) is preferably outfitted with one or more markers oriented such that they may be illuminated with a short wavelength light source and that the light emitted from the markers may be observable to an optical imaging system.
  • Optical filters 60 (FIG. 1 ) may be used to reduce background light and to discriminate among the emissions of multiple markers, thereby reducing the complexity of the image processing algorithms and improving overall system performance. Such a system works well in indoor conditions where diffuse incandescent or fluorescent light is present.
  • the markers 30 may be patches affixed to the objects or parts of objects to be tracked. Fixation may be by any known or later-developed technique, such as sewing, hooks and loops, and adhesives (e.g., pressure-sensitive tape, double-sided tape). Where a marker 30 is to be affixed to a non-planar surface, a movable surface, an outfit designed for wearing on a human body, or any similar surface, it is preferable that the marker 30 be of a soft, flexible material.
  • the motion of an object, multiple objects, or parts of an object or objects are recorded by an imaging device of the imaging system 50, the data are analyzed using digital movie software or similar software.
  • the motion of an individual marker (and therefore of an individual object or part of an object) can then be extracted from the data by selecting a specific emission color of the marker of interest. Where a patterned marker is employed, the motion of the marker of interest may be based on both the emission color and the specific pattern of the marker.
  • CdSe nanocrystals (1 ml_, 40 mg/mL in toluene, emission maximum 530 nm) were evaporated under a stream of nitrogen.
  • the solid residue was redissolved in chloroform (10 ml_).
  • the solution was then mixed with a chloroform solution of poly(maleic anhydride -alt-octadecene) (1 g in 10 ml_).
  • the solution was then evaporated until dry.
  • the solid residue was then added to a 4% dimethylamine solution (5 g) and heated to 80 degrees Celsius to form a yellow solution.
  • CdSe nanocrystals (1 ml_, 40 mg/mL in toluene, emission maximum 530 nm) were evaporated until dry under a nitrogen stream.
  • the solid was dissolved into 10 ml_ dichloromethane and mixed with 10 g of Integrity 1100D (from Hexion).
  • the mixture was then ultrasonicated in a Branson Ultrasonic disperser for 2 minutes to form a milky emulsion.
  • the emulsion was then heated to 60 degrees Celsius to remove the dichloromethane, and resulted in a clear yellow solution.
  • the viscosity is about 20 cps in a Zahn Cup #3.
  • the ink was then ready for flexographic printing.
  • CdSe nanocrystals (1 ml_, 20 mg/mL in toluene, emission maximum 530 nm) were added to 1.5 g polyvinyl acetate) (XX210 from AirProducts), with 0.5 g of water. The mixture was then ultrasonicated in a Branson Ultrasonic disperser for 2 minutes to form a milky emulsion. The ink was then ready for screen printing.
  • CdSe nanocrystals (1 ml_, 40 mg/mL in toluene, emission maximum 530 nm) were evaporated until dry under a nitrogen stream.
  • the solid was dissolved into 10 ml_ dichloromethane and mixed with an SP330 resin solution in dicholoromethane (15%).
  • the total resin content was increased to about 30-35% by evaporating off the dichloromethane.
  • the solution was then coated onto a PET film to form a thermal transfer ribbon.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Led Devices (AREA)
  • Luminescent Compositions (AREA)
  • Electroluminescent Light Sources (AREA)
  • Length Measuring Devices By Optical Means (AREA)

Abstract

La présente invention concerne des marqueurs comportant des nanocristaux semi-conducteurs d'émission de lumière ainsi que leurs procédés d'utilisation dans un système de poursuite optique. L'utilisation de nanocristaux semi-conducteurs ayant différentes longueurs d'onde maximales d'émission permet la discrimination de marqueurs individuels parmi une pluralité de marqueurs. Selon certains modes de réalisation, les nanocristaux semi-conducteurs sont incorporés par une mise en motifs sur un substrat.
PCT/US2008/052620 2007-02-01 2008-01-31 Marqueurs comportant des nanocristaux semi-conducteurs d'émission de lumière et leur utilisation Ceased WO2008095081A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US89868107P 2007-02-01 2007-02-01
US60/898,681 2007-02-01

Publications (2)

Publication Number Publication Date
WO2008095081A2 true WO2008095081A2 (fr) 2008-08-07
WO2008095081A3 WO2008095081A3 (fr) 2008-09-25

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9346998B2 (en) 2009-04-23 2016-05-24 The University Of Chicago Materials and methods for the preparation of nanocomposites

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7164117B2 (en) * 1992-05-05 2007-01-16 Automotive Technologies International, Inc. Vehicular restraint system control system and method using multiple optical imagers
US7079241B2 (en) * 2000-04-06 2006-07-18 Invitrogen Corp. Spatial positioning of spectrally labeled beads
US20050059031A1 (en) * 2000-10-06 2005-03-17 Quantum Dot Corporation Method for enhancing transport of semiconductor nanocrystals across biological membranes

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9346998B2 (en) 2009-04-23 2016-05-24 The University Of Chicago Materials and methods for the preparation of nanocomposites
US10121952B2 (en) 2009-04-23 2018-11-06 The University Of Chicago Materials and methods for the preparation of nanocomposites

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Publication number Publication date
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