AFFIDAVIT OF Pamela Stansbury
`
`STATE OF NEW YORK
`
`COUNTY OF TOMPKINS
`
`)
`) ss.
`)
`
`Pamela Stansbury being of full age and duly sworn, deposes and says as follows:
`
`1. I am an employee of the Cornell University Library, and specifically Library Technical
`Services, located at Cornell University, Ithaca, New York 14853. I have personal
`knowledge of the facts set forth below.
`
`2. I am the Administrative Supervisor in Library Technical Services, which maintains
`bibliographical and processing information for many historical documents. I have held
`such position since 1996.
`
`3. Included in the Library's historical collection are various publications. As part of that
`collection, the Library maintains custody of an original issue of Applied optics, Volume
`10, Number 1, January 1971, which includes the paper Photoluminescent conversion
`of laser light for black and white and multicolor displays. 1: Materials I by L.G. Van
`Uitert, D.A. Pinnow, and J.C. Williams.
`
`4. Mr. Richard F. Moncrief requested information about Applied optics, Volume 10,
`Number 1, January 1971- specifically when this item was first made publicly available
`by the Library. As best I can determine, the publication was publicly available at the
`Cornell University Library as January 5, 1971.
`
`:
`ANDREA DENISE SMITH COLON
`NOTARY PUBUC-STATE OF NEW YORK:
`Tompkins County
`\
`Registration #01SM6276256
`Commission Exp. 02/11/201.7
`
`VIZIO 1021
`
`

`
`~~~-PPiied
`Optics
`
`January
`1971
`
`~
`0.-----~----~----~----~------~----~----~----~
`
`550
`
`60
`
`10
`
`530
`
`700
`
`0 r-
`0
`
`0 w
`0
`
`50
`0
`If)
`
`0
`
`y
`
`0
`=r
`0
`
`0
`
`0
`
`0
`0
`
`~~.o-o----~o.-to--~~.2-0 ----o+. 3-0---x~0.~4o _____ o+. s-o----~o.-so _____ o~. 7-o--~o. oo
`
`CHROMATICITY DIAGRAM
`
`VIZIO 1021
`
`

`
`Applied
`Optics
`
`VOLUME 10
`NUMBER 1
`JANUARY
`1971
`
`Geo~e.,·;~;rot.':::.!C,:~b~"L.•t;.~~d~':r,O" Varian""• or Color Matching by 14
`A Visual Tristimulus Projection Colorimeter-A. Valberg
`Adjustment or the Munseii-Value and W*-Scales to Uniform Lightness Steps
`for Various Background Reflectancea-C. C. Semmelroth
`Internal Reflection Spectroscopy: Validity of Effective Thickness Equations
`- N. J. Herrick and A. I. Carlson
`Hadamard-Transform Exhaust-Analysis Spectrometer-J. A. Decker, Jr.
`A Grazing Incidence Monochromator for Satellite Studies of the Solar Hell
`Lyman-a Line at 303.1 A-P~ J. Bowen, J . A. Bowles, W. M. Glencross, R. J.
`Speer. A. F. Timothy, J . G. Timothy. and A . P . Willmore
`A Convenient Technique for Determ in ing the Relative Ouontum Efficiency of
`a Monochromator and Detector System-J. L. Konl, L J. Curtis, D. A.
`Chojnacki, and R. M. Schectman
`Motion Blurring with Decaying Detector Response-L Levi
`Elec~~~::-~~a:A'6fo~f the Amplitude and Phase fluctuations of a Wave
`
`8
`14
`u
`
`24
`28
`
`34
`
`38
`
`-.....42
`
`46
`51
`
`58
`
`65
`
`74
`
`11
`
`87
`
`" 105
`
`lOt
`
`~114
`11.9
`
`132
`136
`141
`
`144
`
`150
`
`154
`
`~161
`
`168
`
`174
`
`.......... 112
`
`187
`
`1!3
`
`201
`
`A Simple Double Beam Accessory for Absorption Spectroscopy-K . Leutweln
`Spectral Absorption Characteristics of the Major Components of Dust Clouds
`-D. F. Flanigan and H . P. DeLong
`Effects of Argon Atoms on the Self-Absorption and the Intensity of Hg 2537-A
`Radiation In Hg + Ar Dlschuges-T. J. H ammond and C. F. Gallo
`Statistical Band Model Parameters and Integrated Intensities for the 5.9-p,
`7.5 I'• and 11.3 " Bands of HNO, Vapor-A. Goldman. T. G. Kyle. and F. S.
`B onomo
`Radiance and Polarization of Light Reflected from Opti<J~IIy Thick Clouds(cid:173)
`G. W. Kattawar and G . N . Plass
`Rad~!~0s".;!~~~t~pt~cha,ni:~e1:ia~:!.:~~~k~edl~~~~ H~'h~~fe':~~ann~:~~i~i.e~~
`Schroeder
`Damping of Lattice Vibration s in Sollda-J . N. Plendl
`The Correction or Optical Aberrations by Neutron lrrodl1tlon-P. Sinai
`1m aves of Truncated One- Dimensional Period ic Bar T~rgets In Aberration·
`L imited Optical Systema-J. W. Foreman, Jr., G. H. Hunt, and E. K. Lawson
`Influence of Scattered Radiation on Narrow Field of VIew Communication
`links-D. E. Setzer
`Small-Angle Scattering of light by Ocean Water-H. T. Yura
`Bidi[=~~~~:~ ~~tf~~ ~~::~~t~ri!~~·R~f A~~~l~e~reen Soybean and Corn
`Clneholomicroscopy of Small Animal Mlcroclrculation-M. E. Cox, R. G.
`Buckles, and D. Whitlow
`Calorimeter for Laser Energy Measurements--M. M. Birky
`The co, Laser Signature Problem-P. C. Cia spy and Yoh-Han Pao
`co, Laser with Simult-.neous Active and Passive 0-Swltching-0. M . Stafsud d,
`0. Ersoy. and S. P1zzica
`A Precision Variable, Double Prism Attenuator for co, Lasers-T . Oseki and
`S. Saito
`Photoluminescent Conversion of Laser Llvht for Bl1ck 1nd White and Multi·
`color Dlspl•ys. 1: Materlals-L. G. Van U ltert. D. A. Pinnow, and J. C.
`Williams
`Photoluminescent Conversion of Laser Light for Black and While and Multo·
`color Displays. Z: Systems-D. A. Pinnow. L. G. Van U otert, and M.
`Feldman
`Measurement of the Deem P•ram•ters of a L•aer Beam end Its Diffraction
`Field, Using a Hologram-T. Miyamoto and K. Yasuura
`A Contribution to the Comparison of Single Exposure •nd Multiple Exposure
`Storage Holograms-M. Lang. G. Goldmann, and P. Grar
`Holographic Subtractlon-K. Bromley. M . A. M onahan, J. F. Bryant, and B. J.
`Thompson
`A Hologr•phlc Interferometer for Me•suring Radl•tlon Energy Deposition
`Profiles In Transparent Liquids-E. K. Hu ssmllno
`·
`A Generalized Technique of Two-WavelenJth, Nondiffuse Holographic
`fnterferomet<Y"-F. Weigl
`A Technique for Recovering Doppler Line Profll•s from hbry-Perot Inter·
`ferometer Fringes of Very Low O.nslty-P. B. Hays and R. G. Roble
`Schlie reA Vlsuallz•tlon Dev ice Allowing an Arbltr•ry Orientation of the Lines
`with Respect to the Sc•nlling Dlrectlon-R. Grossin. M. Jannot, and S.
`Viannay
`
`January 1971 I Vol. 10, No. 1 / APPLIED OPTICS A5
`
`A monthly publication of the
`Optical Society of America
`
`J. N . Howard Editor
`P. R. Wakelfng Managing Editor
`
`Cover: See page 153.
`
`Published monthly by the Optical Socletyol
`America at 20th and Northampton Streets.
`Easton, Pa. 18042. Office of the Editor:
`FCRL, Bedford, Mass. 01730; 617·861·
`281. Office of the Managin~ Edotor:
`INC1 1613 Nineteen th Stree N.W.,
`ashonl{ton, D.C. 20009;
`202· 87·1773.
`Advertljong_ ofllce: American Institute of
`Physics, 335 E. 45th Street, New York, N.Y.
`10017; 212·MU 5·1940. Subscription rates
`gl!r year: Included in membershop dues to
`SA members; nonmembers and libraries
`$35. Songle copies $4; complete volumes
`$40Pa. Second class postage paid at Easton,
`0 Copyrll{ht 1970 by the Optical
`•
`S
`ociety of Ameroca, Inc.
`
`WW
`
`4A
`
`VIZIO 1021
`
`

`
`Photoluminescent Conversion of Laser Light for
`Black and White and Multicolor Displays. 1: Materials
`
`L. G. Van Uitert, D. A. Pinnow, and J. C. Williams
`
`.\ number. of pbo~olurninet!Ce~~ materials have been found w have properties that make them extremely
`u•eful ~or ~mprovm~ the quahty of laser display liS well liS offering ~implification~ for multioolor systems.
`~he ~rtnCJpal funcl•on of the~~e materials is that or oolor conversion when coated onto a l&>er illuminated
`Vlt'~u·~ R~recn. A I!('()OOdary, yet significant, role is that. or rendering the converted light incoherent.
`Tht~ elurunate<~ .the unpl~t granular or epeckly texture Ill "<>cia ted with direct viewing of diffW;e.ly acat(cid:173)
`tt>red co~erent light. It •~ oo~cluded that virtually any vi•ible color may be achieved by photolumine~~cent
`('flnvent•on of a monorhromall~ blue or ultraviolet la..«er beam.
`
`I.
`
`Introduction
`~n a recent review of hll:!or diHplay technology Baker•
`pomted out that conRidcmblo motivation in this field
`stcmH from the promi~ of producing a cathode ray tube
`type of display with e.•l.'lCntinlly unlimited screen ~izc.
`He concluded that although ndequate light benm modu(cid:173)
`lation and scanning tc<'hniquc~; ure prc~nllv available
`brol\dly applicable 0<1uipment awaits the development
`of an efficient mult icolor lasor l!ourcc.
`Although liuch a mult icolor source would indood be
`der~irable, the pro!lpcctH for its renlization evrn in the
`distant future, arc !!pcculativc. Howeve'r, it U; clear
`that etficil•nt monochromatic or limited color mngc lnser
`sources can and will be developcd. 1 The purpot<C of the
`prc.'ICnt work is to show thnt a monochromatic lnser
`R?urce iK Kati.Hfactory for white light and multicolor
`dtl!plnyli when advantage is taken of photoluminescence
`tho nbtmrption of light of ouo wtwelongth and t,ho sub~
`scqurnt <>missions at another wavelength. By prop(cid:173)
`erly coating a viewing HCr(l('ll with exi11ting organic and
`inorganic pho~phors it i!! po~<sible to efficiently convert
`n~onochromatic blue or ultraviolet hvlor light into
`Vtrtually any vi~<ible C(llor in<'ludiug white. Au addi(cid:173)
`tional benefit of thi!! conv<>n-ion iii the elimination of
`the unplca.'lnnt grauulnr texture generally Ill ociAtcd
`with direct viewing of diffusely scattered coherent
`light ,• becau.'!C the converted I ight is incoherent.
`The bllllic phyt~ics of pbotolumineBCent convrrsion is
`quite simple. Photon!! from a light beam such ruJ a
`laecr beam are absorbrd in n material which is thereby
`rail!(l<l to un excited state. Tlds excitation equilibrates
`in a brit'f interval, typicully w-• sec to w-s sec. Equil-
`
`The autho111 are with Bell Telephone Laborat.oril'l!, Inc., Mur(cid:173)
`ray Hill, New Jeraey 07974.
`Received 16 March 1970.
`
`150 APPLIED OPTICS I Vol. 10, No. 1 / January 1971
`
`ibration CIUl proceC<l both rudiatively by tho emission of
`a photon and nonmdint ivcly by, for· example, a series of
`phonon interactions. A material is considered to be a
`phosphor if radiative emission is observed. The rela(cid:173)
`tive trcngth of radiative transitions i pceified in terms
`of the phosphor's quantum efficiency, defined as the
`ratio of emitted photons to ab ·orbed photons. In
`general, the rnergy of the emit wd photons is le.«s than or
`equal to the energy of the ttbsorbed photon ( tokes's
`law). That is, the color of the emitted Light is either
`unchanged or shifted in the direction of longer wave(cid:173)
`lengths.
`In certain limited en~' anti- tokes (shorter
`wavelength) emission is also pos~ible when additional
`ent>rgy is !lupplicd to the single photon e.-'<cited state by
`other means such as thermal excitation or multiple
`photon absorption. 4
`In tho pre,.,ent work we will con(cid:173)
`sider only Stokes emitting phosphors which have suf(cid:173)
`ficiently high quantum efficiencies to be of interest for
`laser display applications. Some emphasis will be
`placed on those materials that can be excited by the
`argon ion IIUler which is presently the most suitable
`source for a laser display sy tern.
`II. Characterization
`There are four basic proportie· that characterize
`photoluminescent materials. They are (1) ab orption
`and emi ion spectra, (2) conver:;ion lifetime, (3)
`qunntum efficiency, and (4) absorption cross section.
`It should be noted that the last three properties can be
`functions of the exciting wavelength. The features
`that make a phosphor desirable for application in laser
`display ystems can be related to these properties.
`First, the phosphor must have a high absorption cross
`section for the exciting laser wavelength so that nearly
`total absorption can take place iu a thin layer of mate(cid:173)
`rial that is coated onto a screen. The phosphor should
`have an emission spectrum in a dcsil'ed wavelength
`
`VIZIO 1021
`
`

`
`range with a high quantum efficiency, say, 50% or
`greater, since the display screen size is limited by avail(cid:173)
`the conversion
`able light intensity. In addition,
`lifetime should be sufficiently shot·t so that the screen
`will not be overly persistent; there is no perceptible
`consequence if the lifetime is exceptionally short_$
`Finally, the phosphor should be inexpensive, stable, and
`preferably nontoxic.
`
`Ill. Materials
`Rather than attempting to cover the broad field of
`phosphors, we will discuss, b:1 way of particular ex(cid:173)
`amples, those materials that we consider to be par(cid:173)
`ticularly suitable for laser display systems. They
`generally fall into two categories, inorganic rare-earth
`phosphors and orgauic dye phosphors. To a lesser ex(cid:173)
`tent we will also consider inorganic compounds that are
`activated by transition metals and other organic mate(cid:173)
`rials such as the aromatic hydrocarbons.
`
`Inorganic Phosphors
`A.
`According to Pringsheim, 6 practically all molecules
`that are photolutninescent in condensed states are
`rather complex. The only exceptions are the positive
`ions of some rare-earth metals. The optical properties
`of these ions are so little perturbed by the surrounding
`medium that, even in crystals, they behave almost like
`isolated atoms, and their energy levels arc well known.7
`The rare-earth Tb!+ is a particularly useful ion since
`the wavelength for maximum absorption of its 6D4
`manifold corresponds quite closely to the blue (4880
`A) emission of the argon ion laser. When this ion is
`embedded in a properly chosen host, such as a tungstate
`or a molybdate, it will emit upon excitation a strong
`greenish-yellow color which has a peak at approximately
`5440 A.7 The lifetime is approximately 0.5 msec,
`and the quantum efficiency is high, approaching 100%.
`We have examined the performance of Na9.6Tb0.5W04
`under excitation by an argon laser ( 4 80 A) and find
`that 1-mm thick sample absorbs approximately 50%
`of the incident beam. This absorption cross section is
`substantially lower than optimum since a considerable
`thickness of material would be required to coat a display
`screen.
`
`1.0,.---------.------...,
`~
`~ ... 0.5
`
`ABSORPTION
`
`EU EMISSION
`
`2:
`tc
`..J "' 0::
`
`WAVE LENGTH (A)
`
`Fig. I. Relative absorption spectra of TbH and EuH and the
`emission spectra of Eua+. When these two rare-earth ions are
`inrluded in the same host, such as NauTbe.uEuo.uWO,, a.bsorp(cid:173)
`lion of-argon lru;er radiation at 4_880 A is du.e to Tbl+wh.ile excita(cid:173)
`lion transfer to Eua+ results in the characteristic Eua+ emission
`spectrum which peaks in the red at 614.0 A.
`
`/EMISSION
`
`:r
`....
`~
`....
`
`0::
`
`"'0.~ ! 0::
`
`WAVE LENGTH (A)
`
`6000
`
`7000
`
`Fig. 2. Relative absorption and emission spectra of YAG:Ce.
`The broad absorption band is due toad-baud excitation.
`
`It is possible to achieve other colors by photolumines(cid:173)
`cent conversion using different rare-earth ions. For
`exam11le, Sm~+ has a peak emission at 59 0 A, EuH at
`6140 A, Dy!+ at 5740 A, and Era+ at 5520 A..7 How(cid:173)
`ever, none of these transition!-' other than those for TbH
`can be directly excited to any extent by the 4 0-A line
`of the argon laser. Generally, shorter wavelength ·
`excitation is required. However, indirect excitation of
`Eu!+ is possible through an intermediate Tb!+ ion.8
`For example, excitation transfer from TbH to EuH in
`Nao.,Tbo.2SEuo.2sW04 causes this material to emit a
`strong red color under 4 0-A illumination. The ab(cid:173)
`sorption bands of TbH and EuH and the emission of
`EuH are displayed as a function of wavelength in Fig.
`1. The absorption cro s section, quantum efficiency,
`and lifetime of this material nre s.imilar to Nao.~Tbo.~­
`W04 discussed above.
`The Ce!+ and EuH ions are exceptions to the general
`observation that the fluorescence of rare-earth ions is
`little affected by the host. This is so because their
`emissions are from d-bands which strongly interact with
`the crystal field.$ A rather unusual but useful material
`is made by adding cerium to Ya.Als01s (Y AG). The
`lower excited states of the crystal field components of
`tue 5d configumtion of the YAG: Ce composition are
`sufficiently low in energy that absorption of 4 80-A
`light hecomes appreciable. 1° Figure 2 shows the ab(cid:173)
`sorption and emission spectra in detail. Note that the
`peak of the etnission spectrum occurs at 5500 A, the
`wavlength at which the eye is most sensitive. We
`have found that at 4 0 A the absorption cross section
`is approximately 30 dB/ mm/ wt %of Ce added to the
`Y AG host. In addition to this relatively large absorp(cid:173)
`tion cross section, this compound has a very short life(cid:173)
`time of approximately 0.07 ~sec (Ref. 11) and a quan(cid:173)
`tum efficiency of approximately 70%. 10 These proper(cid:173)
`ties make YAG:Ce very attractive for display screen
`this material may be
`applications. Furthermore,
`tuned for a particular Ube. By replacing some Y with
`Gd the peaks of the absor·ption and emission spectra
`shift to somewhat longer wavelengths, while replacing
`Al with Ga causes the opposite cffect. 10 Other Ce8 + and
`Eu2+ compositions that .have been investigated9•10
`require excitation at wavelengths substantially shorter
`than 4 0 A, general!y in the ultraviolet. 4
`In addition to the rare-earth compounds, there are
`large clas8es of inorganic phosphors ~which have II- VI
`hosts such as ZnS and activators such as Bi, 1\In, Cu,
`
`January 1971 I Vol. 10, No. 1 I APPLI ED OPTICS 151
`
`VIZIO 1021
`
`

`
`T1ble I. Absorption 1nd Fluores~• n~e Bi nds of Dyes In
`Aqueous or Al~oholi~ Solutions, 1fter Prlngshelm 11·•
`
`First
`absorption
`band
`
`Fluorescence
`Color
`Dnud
`
`llV
`
`2!)00-4600 violet
`(3200)
`strong
`4400-5200 5100 -5900 yellow-green
`(4940)
`(51 0)
`very strong
`4500 li(j()() 1)200 6000 yellow
`
`st.rong
`(5400)
`(5170)
`4600 5560 51 0 5 0 yellow
`[),'l7J
`we11k
`51llS
`
`(M38)
`
`.%00 6700 orange
`vrry weak
`(6000)
`
`4 00 6000 5500 7000 red
`(6.100)
`(60.10)
`strong
`f~o'l60 6020 yellow
`4 00 5900
`(5550)
`strong
`(5260)
`4.550 600() 6600 GAOO o•·nnge
`medium
`54.00 5900 5600 6500 orange
`medium
`
`uv- 5200
`uv-5400
`
`3000-4.500 4000-4800 blue-violet
`mt>ditLm
`4750 6400 green
`;i050~700 greenish-
`(5850)
`yellow
`medium
`4700 6500 green weak
`4S.~O 6600 yellowish-
`green
`strong
`
`uv-5 100
`uv- .3000
`
`4()()0...6000
`(5240)
`(53!10
`
`iiJOO 7000
`(6000)
`
`red Rtrong
`
`yellow-red
`
`dayglow phenomenon has found considerable u e in
`advertising display and is due to strong a bsorp(cid:173)
`tion of blue and green light with subsequent emission
`at the various longer wavelengths. 13
`The fluorescing hydrocarbonR and dyes are em(cid:173)
`ployed in very dilute form in order to achieve optimum
`quantum efficiency. Usually pigments (solid particles
`that carry dye) are formed by diR olving the dye in an
`organic resin solution which is subsequently condensed
`to an im•olublo state by tho o,pplication of heat.u
`In
`certain ca cR the efficiency is enhanced if the dye is
`adsorbed on <'OIIoids such as fibers or gel particles of
`high polymcr~. 14 Rcprc.~entative materials and the
`color which f hey fluoresce include pyrelene (blue),
`fluorescein (vcllow-grecn), eosin (yellow), Rhodu.mine-B
`(red), Rhodumin(}-6C: (yellow), acridine (blue), acri(cid:173)
`flavine (yellow-green), naphthalene red (red), Auro(cid:173)
`min(}-0 (yellow-green), and 7-diethylamino-4 methyl
`coumarin (blue) as well as other xanthene, azine, oxa(cid:173)
`zine, thioazinc, acridine, flavin, naphthalimide, and
`coumarin derivatives. Additional data on the absorp(cid:173)
`tion and emission of selected dyes are given in Table I. 1
`'
`We luwe examined in con!'licinrable detail a naph(cid:173)
`thalimide
`dye, 4-amino--1,8-napbthal-p-xenylimide
`(yellow-green), aud two Rhodamine dyes (orange and
`red) that have been ctu>t into an tidhesive coated plastic
`film for commercial use (Minnesota. 1\rlining m1d Manu(cid:173)
`facturing Company, Scotchcal F luorescent Film, types
`34 3, 3484, and 34 .1). Their emission spectra for
`48 0-A excitation, which are shown in Fig. 3, exhibit
`penks at 5200 A (yellow-green), 0000 A (orange), and
`6200 A (red). We have determined that their lifetimes
`a re all considerably less tho.n 1 IIsee, a nd their absorp(cid:173)
`tion cro~'<s sections are so large that the entire laser beam
`is absorbed within the thin films which are approxi(cid:173)
`mately 0.1 mm thick. Their absorption bands are
`quite broad, including essentially all the violet and blue
`nnd a portion of the green. We have estimated from
`analysis of rPReclion spectra reported by Ward'6 that
`
`Compounds
`
`I. Xanthene
`Fluoran
`
`Fluorescein
`(l>ihydroxyfluoran)
`Fhlin
`(Tetrabromofluo-
`rescein)
`Erythrosin
`(Tetraiodoftuo-
`rescein)
`Rose beng11le
`(Tetraiodotetra-
`chlorofluorescein)
`Rhodamine B extra
`
`Rhodamine llG
`
`Acridine red
`
`Pyronine B
`
`II. Acridine
`Arridine
`
`Acridine yellow
`Euchrysine
`
`.,
`
`Rheonine A
`Acriflavine
`(Trypatlavine)
`
`Ill. Azine
`Magdala red
`
`Sal ranine
`IV. Thiazine
`Thionine
`
`orange
`4 00--6300
`medium
`(5800)
`red medium
`Methylene blue
`5500 7000
`• Approximate limita of band~ in A; penkll of bnnds in
`pBTenthe:<es.
`
`and Ag, and uumy activated tungstates, molybdates,
`vana.dates, phosphates, germnnlltcs, and silicates that
`also have strong band fluorescence. " We have not
`to be pnrticulo.rly useful since
`found these material
`moRt are not readily excited by argon radiation or are
`of inadequate quantum efficiency.
`
`B. Organic Phosphors
`T here are a number of aromatic hydrocarbons and
`organic dyes that when propel'iy treated exhibit strong
`fiuoresceoce over a broad portion of the visible spec(cid:173)
`trum. Under white light ilium in at ion several of these
`appear to glow with a po.rticulnr colo1· ranging from
`greenish-yellow through orange to bright red. This
`
`152 APPLIED OPTICS I Vol. 10, No. 1 I January 1971
`
`Fig. 3. Relative emission spectra of naphthalimide dye (3485)
`and Rhodnmine dyes (3483 and 3484) due to excitation by the
`4880-A line of an argon laser.
`
`VIZIO 1021
`
`

`
`their quantum efficiencies are above 50%. Thus,
`these materials are almost perfectly suited for Ia er dis(cid:173)
`play systems.
`The colors of these fluorescing dyes may be modified
`somewhat by varying the type of carrier which is used
`to form pigments and, to :1 lesser extent, by varying
`the type of vehicle, or binder, into which the pigment is
`incorporat<:d. It is also possible to modify colors by
`combining fluorescent dyes with nonfluore cent dyes
`that selectively absorb a portion of the emission spec(cid:173)
`trum. For example, the emission spect.rum of ·t he
`naphthalimide dye (ty pe 3485J show in Fig. 3 peaks at
`5300 A, in the green. Normally this fluorescence ap(cid:173)
`pears to have a yellowish-green cast due to tho broad
`tail of the emission spectrum which extends into the
`yeLlow and red. However, this tail can be substan(cid:173)
`tially reduced by tho addition of a nonfluorescing green
`toner such as phthalocyatline, 13 which a bsorbs in the
`yellow and red. The result then is fl. t radeoff of
`brightness for the ability to limit t he spectral content.
`In contras t to t he many yellow and red cmitti11g dyes,
`blue emitting dyes are less common. H owever, ex(cid:173)
`amination of py relcne in dilute a lcoholic solutions in(cid:173)
`dicates that. it is blue fiuorescing when excited by short
`wavelength blue light S);ICh as 4579-A emission of an
`argon laser or the 441 6-A emission of a cadmium laser,
`while it becomes green fluorescing under longer wave(cid:173)
`length blue excit.at.ion such as the 48H0-A line of an a r(cid:173)
`gon laser. In addition, pigments of coumarin which
`fluoresces blue under near ultra violet excitation a re
`commercially availa ble. 13
`
`IV. Conclusion
`There exists a sufficiently wide ra nge of efficient m:(cid:173)
`ganic and inorgauic phosphors t hat can be excited by
`laser wavelengths ranging from the ultraviolet to gn~r.n
`and that have emission spectra covering the entire
`visible. For example, a suitable combination of blue,
`green, and red emitting phosphors can be mude to
`fluoresce any color desired including white when i.llumi(cid:173)
`nated by a blue or ultravi.olct laser source.
`If the
`
`source itself is blue, a portion of its intensity may be
`directly scattered and blended with the emission from
`green and red phosphors to achieve a similar color ·
`gamut. These concepts have been verified using an .
`argon ion laser source which emitted only blue 4880-A
`radiation. In conclusion, photoluminescent conver(cid:173)
`sion of a monochroma tic laser source provides an attrac(cid:173)
`tive means for achieving white and light and multicolor
`for display system applications.
`
`The authors acknowledge with thanks helpful dis(cid:173)
`cussions with E. A. Ch andro s and C. V. Lundberg
`concerning organic dyes and pigments. The authors
`also t hank H. W. Grodkiewicz, A. G. D entai, and C . J.
`Schmidt for t he growth and preparation of test samples
`and S. H. Williamson for assistance in experimental ·
`measurements.
`References
`1. C. E. Baker, IEEE Spectrum 5, 39 (December 196S).
`2. J . E. Gcusic, II. J . Levinslein, S. Singh, R. 0. Smith, and L.
`G. Van Uitert, Appl. Phys. Lett. 12, 306 (1968).
`3. L . H . Enloe, Dell System Tech. J . 46, 1479 (1967).
`4. P . Prin~tSheim, Fluorucence and Phosphorescence (lutersci(cid:173)
`ence, New York, 1949), pp. 1- 10.
`5. J . D. Gould and W. L. Makous, I nformation Display 5,
`25 (November/ Deccmbe1· 1968).
`6. Ref. 4, pp. 285-289.
`7. L. G. Van Uitert, J. Electrochem. Soc. 114, 1048 (1967).
`8. L. G. Van Uilert and R. R. Soden, J . Chern. Phys. 36, 1289
`(1962).
`9. G. Bla.~se, W. L. Wattrnaker, J . W . ter Vrugt, and A. Bril,
`Philips Res. Rep. 23, 189 (1968).
`10. G. Blas.~e and A. Bril, J . Chern. Pbys. 47, 5139 (1967).
`11. G. Blasse and A. Bril, Appl. Phys. Lett. 11 , 53 (1967).
`12. Ref. 4, pp. 594-645.
`13. Day-Gio Color Corporation, Cleveland, Ohio, Tecl1. Booklet
`No.ll70-A.
`14 . .!!:. U. Bobalek and W. von Fisher, Organic P rotective Coatings
`(Reinhold, New York, 1953), pp. ll5- 118.
`15. Ref. 4, p. 423.
`16. R. A. Ward, "The Day-Glo' Daylight Fluorescent Color
`Specification System (Day-Glo Color Corp., Cleveland,
`Ohio).
`
`COVER
`
`This mont h's cover shows constant ·hue and saturation loci derived from geodesic chroma·
`ticity diagram. The radii of the constant·saturation circlas on the ~ • ., diagram were 20n;
`the angular separations of points were 18°/n. The constant·hue loci shown correspond to
`radii separated by t s • in t he f ,'! diagram.
`
`January 1971 I Vol. 10, No. 1 I APPLI ED OPTICS 153
`
`VIZIO 1021