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`CHROMATICITY DIAGRAM
`
`LOWES 1027, Page 1
`
`LOWES 1027, Page 1 :
`
`VIZIO EX. 1027 Page 0001
`
`VIZIO Ex. 1027 Page 0001
`
`

`

`Applied
`Optics
`
`VOLUME 10
`NUMBER 1
`
`JANUARY
`
`1971
`
`Awm—u—wh—au~—I
`.14m.-...._.__...
`
`Geodesic Chromaticl Die ram Based on Variances ICoIor Matchin b 14
`Normal cheering—D.
`. MacAdam
`o
`l y
`A Visual Tristimulus Projection Calorimeter—A. Vaiberg
`Adjustment oi the MunseII-Valua and Wt-Scalea to Uniform Lightness Steps
`for Various Background Reflectance—C. C. Semmelroth
`-—N. .i. Hamck and A. I. Carlson
`Internal Reflection Spectroscopy: Validity of Effective Thickness Equations
`"adamant-Transform Exhaust-Analysis Spectrometer—J. A. Decker. Jr.
`A Grazing Incidence Monochromator for Satellite Studies of the Solar Hell
`Lyman-a Lineat 303.8 A—PT J. Bowen. J. A. Bowies. W. M. Glencross. R. J.
`Speer. A. F. Timothy. J. G. Timothy. and A. P. Willmore
`A Convenient Technique for Determining the Relative uantum Efficiency of
`a Monochromator and Detector System—J. L. he i, L. J. Curtis. D. A.
`Choinacki. and R. M. Schectman
`Motion Blurring with Decaying Detector Response—i. Levi
`Electrical Recordin
`of the Amplitude and Phase Fluctuations of a Wave
`Front—M. Berta on:
`
`A Simple Double Beam Accessory for Absorption spectroscopy—K. Leutwein
`Spectral Absorption Characteristics of the Major Components of Dust Clouds
`—D. F. Flanigan and H. P. DeLong
`of Hg 2537-A
`Effects of Argon Atoms on the Self-Absorption and the lntanol
`. Gallo
`Radiation in Hg + Ar Discharges—T. J. Hammond and c.
`Statistical Band Model Parameters and Integrated Intensities for the 5.9- .
`Bonomo
`7.5 .. and 11.3 ,. Bands of HNOa Vapor-uni. Goldman, T. G. Kyle. and F. E
`
`Radiance and Polarization of Light Reflected from Optically Thick clouds—-
`G. W. Kattawar and G. N. Plass
`
`Radiation-induced Chanflas in Refractive Index and Absorption Coefficient
`Schroeder
`for Several Optics!
`aterials—D. R. Olson. H. D. Dieselman. and J. B.
`Dam ping of Lattice Vibrations in Solids—J. N. Plendl
`The Correction of Optical Aberration: by Neutron Irradiation—P. Sinai
`Images of Truncated One-Dimensional Periodic Bar Targets in Aberration-
`irnitad Optical Systems—1W. 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
`Bidirectional Scattering Characteristics of Healthy Green Soybean and Corn
`Leaves in viva—H.
`. Breece ill and R. A. Holmes
`Cineholomicrosco y of Small Animal Microcirculatlon—M. E. Cox, R. G-
`Buckles, and
`.Whitlow
`
`Calorimeter lnr Laser Energy Measurements—M. M. Birky
`The CO. Laser Signature Problem—P. C. Claspy and Yoh-Han Fan
`(:09 Laser with Simultaneous Active and Passive O~Switching-0. M. Stafsudd.
`O. Ersoy, and S. Piznca
`.
`l o
`A Prsecgsajgn Variable, Double Prism Attenuator for CO: Lasers—T. Oseki and
`Photo-luminescent Conversion of Laser Li ht for Black and White and Multi-
`
`color Displays. 1: Materials—L. G. an Uitert, D. A. Pinnow, and J. C.Williams
`
`Photoiumlnamnt Conversion of Laser Li ht for Black and White and Multi-
`
`coior Displays. 2: Systems—D. A.Feldman
`innDW. L. G. Van Uitert. and M-
`
`Measurement of the Bean-i Parameters of a Laser Burn and Its Diffraction
`Field, Using a Hologram—T. Miyamoto and K. Yasuura
`A Contribution to the Com arisen of Single Exposure and Multiple Exposure
`Storage Holograms— . Lang, G. Goldmann, and P. Graf
`Hole raphic Subtraction—K. Bromley, M. A. Monahan, J. F. Bryant. and B. J.
`hompson
`
`A Holographic Interferometer for Measuring Radiation Energy Deposition
`Pro ilas in Transparent Liquids—E. K. HusSmann
`A Generalized Tachnl no of Two-Wavelength, Nondifluse Holographic
`Intarlaromatry—F.
`eigl
`A Technique for Recovering Doppler Line Profiles from Peary-Perot Inter-
`ferometer Fringe: of Very Low Density—F. B. Hays and R. G. Ruble
`Schlioren Visualization Device Allowing an Arbitrary Orientation of the Lines
`with Respect to the Scanning Direction—R. Grossin. M. Jannot. and S,
`Viannay
`
`ll
`
`1!
`
`”fl
`
`38
`N41
`46
`51
`
`65
`
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`
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`
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`9!
`105
`
`109
`
`\111
`119
`
`132
`136
`Ill
`
`1"
`
`150
`
`154
`
`\161
`168
`
`114
`
`\I 132
`131
`
`133
`
`201
`
`January 1971 / Vol. 10. No. 1 / APPLIED OPTICS A5
`LOWES 1027, Page 2
`LOWES 1027, Page 2
`
`VIZIO EX. 1027 Page 0002
`
`A monthiy publication of the
`
`Optical Society of America
`
`J. N. Howard Editor
`
`P. R. Wakeling Managing Editor
`
`Cover: See page 153.
`
`Published monthly bkthe Optical Society of
`America at 20th and
`orthampton Streets.
`Easton, Pa. 18042. Office of the Editor:
`AFCRL, Bedford. Mass. 01730:
`617-861-
`‘281. Office of
`the Managin
`Editor:
`WING
`1513 Nineteenth Stree , N.W..
`Wasniqgion.
`o.c.
`20009;
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`Advertisingsollice: American institute of
`Famine: 3
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`1
`7
`£12.Mu 5-1940. Subscri tion rates
`members; nonmembers an libraries
`- Ber ear:
`includedin members Educate
`. Single copies 54: complete volumes
`-,
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`.- 533"”“riipicsgtpa‘ir'fistmi
`Society of Amefica. Inc.
`y
`
`VIZIO Ex. 1027 Page 0002
`
`

`

`Phbtoluminescent Conversion of Laser Light for
`Black and White and Multicolor Displays. 1: Materials
`
`L. G. Van Uitert, D. A. Pinnow, and J. C. Williams
`
`A number of photoluminescent materials have been found to have properties that make them extremely
`useful for improving the quality of laser displays as well as offering simplifications for multicolor systems.
`The principal function of these materials is that of color conversion when coated onto alaser illuminated
`viewing screen. A secondary, yet significant, role is that of rendering the converted light incoherent.
`This eliminates the unpleasant granular or speckly texture associated with direct viewing of diffusely scat-
`tered coherent light. It is concluded that virtually any visible color may be achieved by photoluminescent
`conversion of a monochromatic blue or ultraviolet laser beam.
`
`I.
`
`Introduction
`
`In a recent review of laser display technology Baker-1
`pointed out that considerable motivation in this field
`stems from the promise of producing a cathode ray tube
`type of display with essentially unlimited screen site.
`He concluded that although adequate light beam modu-
`lation and scanning techniques are presently available,
`broadly applicable equipment awaits the development
`of an efficient multicolor laser source.
`Although such a multicolor source would indeed be
`desirable, the prospects for its realization, even in the
`distant future, are speculative. However, it iI clear
`that efficient monochromatic or limited color range laser
`sources can and will be developed.2 The purpose of the
`present work is to show that a monochromatic laser
`source is satisfactory for white light and multicolor
`displays when advantage is taken of photoluminescence,
`the absorption of light of one wavelength and the sub-
`sequent emissions at another wavelength. By prop-
`erly coating 8. viewing screen with existing organic and
`inorganic phosphors it is possible to efficiently convert
`monochromatic blue or ultraviolet
`laser light
`into
`virtually any visible color including white. An addi-
`tional benefit of this conversion is the elimination of
`the unpleasant granular texture generally associated
`with direct viewing of diffusely scattered coherent
`light,8 because the converted light is incoherent.
`The beds physics of photoluminescent conversion is
`quite simple. Photons from a light beam such as a
`laser beam are absorbed in a material which is thereby
`raised to an excited state. This excitation equilibrates
`in abrief interval, typically 10"I sec to 10‘8 sec. Equil—
`
`The authors are with Bell Telephone Laboratories, Inc., Mur-
`ray Hill, New Jersey 07974.
`Received 13 March 1970.
`
`150 APPLIED OPTICS / Vol. 10, No.1 / January 1971
`
`ibration can proceed both radiatively by the emission of
`a photon and nonradiatively by, for example, a series of
`phonon interactions. A material is considered to be a
`phosphor if radiative emission is observed. The rela-
`tive strength of radiative transitions is specified in terms
`of the phosphor-’5 quantum efficiency, defined as the
`ratio of emitted photons to absorbed photons.
`In
`general, the energy of the emitted photons is less than or
`equal to the energy of the absorbed photon (Stokes’s
`law). That is, the color of the emitted light is either
`unchanged or shifted in the direction of longer wave-
`lengths.
`In certain limited cases anti—Stokes (shorter
`wavelength) emisaion is also possible when additional
`energy is supplied to the single photon excited state by
`other means such as thermal excitation or multiple
`photon absorption.‘
`In the present work we will con-
`sider only Stokes emitting phosphors which have suf-
`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 laser which is presently the most suitable
`source for a laser display system.
`
`ll. Characterization
`
`There are four basic properties that characterize
`photoluminescent materials. They are (1) absorption
`and emission spectra,
`(2) conversion lifetime,
`(3)
`quantum 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 systems 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 in a thin layer of mate-
`rial that is coated onto a screen. The phosphOr should
`have an emission spectrum in a desired wavelength
`
`LOWES 1027, Page 3
`LOWES 1027, P?e 3
`VIZIO EX. 1027 Page 0003
`
`VIZIO Ex. 1027 Page 0003
`
`

`

`1""er
`
`,:
`‘;
`
`
`
`
`
`.~.:;w-u—rym;=‘rrrte/m;"5—71'7‘
`
`range with a high quantum efficiency, say, 50% or
`greater, since the display screen size is limited by avail-
`able light
`intensity.
`In addition,
`the conversion
`lifetime should be sufficiently short so that the screen
`will not be overly persistent;
`there is no perceptible
`consequence if
`the lifetime is exceptionally short.a
`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, by way of particular ex—
`amples, those materials that we consider to be par—
`ticularly suitable for
`laser diSplay systems. They
`generally fall into two categories, inorganic rare-earth
`phosphors and organic dye phosphors. T0 a lesser ex-
`tent We will also consider inorganic compounds that are
`activated by transition metals and other organic mate—
`rials such as the aromatic hydrocarbons.
`
`A.
`
`Inorganic Phosphors
`
`According to Pringsheim,6 practically all molecules
`that are photoluminescent
`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 are well known.7
`The rare-earth Tb” is a particularly useful ion since
`the wavelength for maximum absorption of its 5D4
`manifold corresponds quite closely to the blue (4880
`.3) 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}
`The lifetime is approximately 0.5 msec,
`and the quantum efficiency is high, approaching 100%.
`We have examined the performance of Na .5Tbu.5W04
`, under excitation by an argon laser (4880 ii) and find
`that l-mm thick sample absorbs approximately 50%
`of the incident beam. This absorption cross section is
`substantially IOWer than optimum since a considerable
`thickness of material would be required to coat a display
`screen.
`
`b
`
`0.5
`
`
`
`HELATIVESTRENGTH
`
` ABSORPTION
`
`4 880
`
`- 6000
`.
`WAVE LENGTH (AI
`
`Fig. 1. Relative absorption spectra of Tb3+ and Eu3+ and the
`Iemission spectra of En“. When these two rare-earth ions are
`included in the same host, such as Naq_5Tbo.25EUu,25W04, absorp-
`tion ofnrgon laser radiation at 4880 3 is due to TbM while excita-
`tion transfer to Eu” results in the characteristic Eu“+ emisaion
`spectrum which peaks in the red at 6140 A.
`
`
`
`_.._‘r.,.74..r._...
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`ABSORPTION
`
`O 5
`
`/EMISSEON
`
`STRENGTH 0
`RELATIVE
`
`3000
`
`4 000
`
`‘
`5 000
`-
`WAVE LENGTH (AI
`
`6 000
`
`'f 000
`
`Fig. 2. Relative absorption and emission spectra of YAG:Ce.
`The broad absorption band is due to a til—hand excitation.
`
`It is possible to achieve other colors by photolumines—
`cent conversion using difierent rare~earth ions. For
`example, Sml+ has a pqak emission at 5980 A, Eu3+ at
`6140 A, Dy3+ at 5740 A, and Er3+ at 5520 A? How-
`ever, none of these transitions other than those for Tb3+
`can be directly excited to any extent by the 4880—3 line
`of
`the argon laser. Generally, shorter wavelength
`excitation is required. However, indirect excitation of
`Eu3+ is possible through an intermediate Tb3+ ion.a
`For example, excitation transfer from Tb3+ to EuH in
`Nat.5Tba.2.-,Euu.25W04 causes this material to emit a
`strong red color under 4880-3 illumination. The ab-
`sorption bands of Tb"er and Eu“+ and the emission of
`Eu“ are displayed as a function of wavelength in Fig.
`1. The absorption cross section, quantum efficiency,
`and lifetime of this material are similar to Nas.5Tbn.5~
`W04 discussed above.
`‘
`The Ce8+ and Eu2+ 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.9 A rather unusual but useful material
`is made by adding cerium to YaAlaOn (YAG); The
`lower excited states of the crystal field components of
`the 5d configuration of the YAG:Ce composition are
`sufficiently low in energy that absorption of 4880-3
`light becomes appreciable.m Figure 2 shows the ab-
`sorption and emission spectra in detail. Note that the
`peak of the emission spectrum occurs at 5500 A, the
`wavlength at which the) eye is most sensitive. We
`have found that at 4880 A the absorptiOn cross section
`is approximately 30 dB/mm/Wt % of Ce added to the
`YAG host.
`In addition to this relatively large absorp-
`tion cross section, this compound has a very short life—
`time of approximately 0.07 psec (Ref. 11) and a quan-
`tum efficiency of' approximately 70%.“) These proper-
`ties make YAG:Ce very attractive for display screen
`applications. Furthermore,
`this material may be
`tuned for a particular use. By replacing some .Y with
`Gd the peaks of the absorption and emission spectra
`shift to somewhat longer wavelengths, While replacing
`Al with Ga causes the opposite effect. 1" Other Ce3+ and
`Eu2+ compositions that have been investigatedi'rl“
`require excitation at wavelengths substantially shorter
`than 4880 11, generally in the ultraviolet.‘
`In addition to the rare-earth compounds, there are
`large classes of inorganic phosphors which have II—VI
`hosts such as ZnS and activators such as Bi, Mn, Cu,
`
`January 1971 / Vol. in. No.1 / APPLIED OPTICS 151
`
`E
`
`LOWES 1027, Page 4
`LOWES 1027, Page 4
`
`VIZIO EX. 1027 Page 0004
`
`VIZIO Ex. 1027 Page 0004
`
`

`

`_ Table l. Absorption and Fluorescence Bands of Dyes In
`__,_'—_——_——-—-—
`Aqueous or Alcoholic Solutions. after Prlngsheimu'“
`
`Rhodnmine 6G
`
`Acridine red
`
`dayglow phenomenon has found considerable use in
`advertising display and is due to strong absorp-
`tion of blue and green light with subsequent emission
`at the various longer wavelengths. 1“
`Fluorescence
`abifziioo
`The fluorescing hydrocarbons and dyes are em-
`Band
`Color
`band
`Compounds
`-——-—"—‘—"—‘—— ployed in very dilute form in order to achieve optimum
`I'ngzflfene
`W
`2900—4600
`violet
`quantum efficiency. Usually pigments (solid particles
`(3200)
`strong
`that carry dye) are formed by dlSSOlVlIlg the dye In an
`Fmomcein
`“(#5200 510(k5900 ”nowgmn
`orgamc resin solution Wthl] is subsequently condensed
`(Dibydmxyfluomn)
`(4940)
`(5130)
`very strong
`to an Insoluble state by the application of heat.” In
`E03111
`'
`4500-5500 520045000 yellow
`certain cases the efficiency is enhanced if the dye is
`(Tetrabromofluo-
`adsorbed on colloids such as fibers or gel particles of
`rescein)
`high polymers.” Representative materials and the
`Erythrosin
`color which they fluoresce include pyrelene (blue),
`(TetTEi?d)0flU0-
`fluorescein (yellow—green), eosin (yellow), Rhodamine—B
`”scam
`(red), RhodaminefiG (yellow), acridine (blue), acri-
`Raggezffididtctm-
`flavine (yellow-green), naphthalene red (red), Auro—
`ch10rofluor85win)
`mine-O. (yellow-green), and 7-diethylamino-4I methyl
`Rhodamine B extra
`coumarin (blue) as well as other xanthene, amne, oxa—
`zine,
`thioazine, acridine,
`flavin, naphthalimide, and
`conmarin‘derivatives. Additional data on the absorp-
`tion and emission of selected dyes are given in Table I. 1"
`We have examined in considerable detail a naph-
`thalimide
`dye,
`4-amino-1,S—naphthal-p—xenylimide
`(yellow-green), and two Rhodamine dyes (orange and
`rod) that have been cast into an adhesive coated plastic
`film for commermal use (Minnesota Mining and Mann-
`facturmg Company, Scotehcal Fluorescent him, types
`3483,3484] and 348?). Their emissmn spectra 'for
`4880-11 excitation, winch are shown lilo Fig. 3, exhibit
`peaks at 5200 A (yellow-green), 0000 A (orange), and
`6200 A (red). We have determined that their lifetimes
`are all considerably less than 1 usec, and their absorp—
`tion cross sections are so large that the entire laser beam
`is absorbed within the thin films which are approxi-
`mately) 011 mu; cthick. Their-1 ablstfilptionl bandisbilire
`qul e roa ,mcu 111g essen .1a ya . ev1oe an
`no
`and a portion of the green. We have estimated from
`analysis of reflection spectra reported by Ward16 that
`
`strong
`(5400)
`(5170)
`460043550 5180-5339 J’EHOW
`5165
`5375
`weak
`(5438)
`55352331300 agate“
`4800—6000 550077000 red
`(5500)
`(6050)
`strong
`4800—5900 5360-6020 yellow
`(5260)
`(5550)
`strong
`4550—6000
`5000—6800 orange
`'
`medium
`5400—5900 560045500 omnlge
`“madmm
`30004500 40004800 bluewiolet
`medium
`uv—5200
`4750—6400 green
`uv-5400
`505045700
`greenish—
`(5350)
`yellow
`medium
`green weak
`4700—6500
`485045500 yellowish-
`319811
`“”0“?
`_
`toggigoo 5.1%ch rad Strong
`(5390
`yellow-red
`4800—6300
`orange
`(5800)
`medium
`
`Methylene blue
`55004000
`red medium
`
`Pyronine B
`II Acridine
`'Acridine
`Acridine yellow
`Euchrysiue
`
`.
`Rheonine A
`AerifiIWiflB
`(Trypflfififine)
`III Azine
`'
`Magda” red
`Safrnnine
`IV. Thiazine
`Thionine
`
`{IV—5100
`Inf-5000
`
`“Approximate limits of bands in 3;; peaks of bands in
`parentheses.
`
`and Ag, and many activated tungstates, molybdates,
`vanadates, phosphates, germanates, and silicates that
`also have strong band fluorescence.12 We have not
`found these materials to be particularly useful since
`most are not readily excited by argon radiation or are
`of inadequate quantum efficiency.
`B. Organic Phosphors
`There are a number of aromatic hydrocarbons and
`organic dyes that when properly treated exhibit strong
`fluorelcence over a broad portion of the visible spec—
`trum. Under white light illumination several of these
`appear to glow with a particular color ranging from
`greenish-yellow through orange to bright red. This
`
`152 APPLIED OPTICS / Vol. 10. No.1 / January 1971
`
`/3453
`
`3434
`
`3485
`
`"o
`
`C
`'25
`E
`5
`3.3 “‘5
`E
`E.J
`5
`
`0 500°
`
`WAVE LENGTH (A)
`550°
`(300°
`
`6 5m
`
`Fig. 3. Relative emission spectra of naphthnlimide dye (3485)
`and Rhodarnine dyes (3483 and 3484) due to excitation by the
`4880—3 line of an argon laser.
`
`LOWES 1027, Page 5
`LOWES 1027, Page 5
`
`VIZIO EX. 1027 Page 0005
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`VIZIO Ex. 1027 Page 0005
`
`

`

`-'W-ym
`
`their quantum efficiencies are above 50%. Thus,
`these materials are almost perfectly suited for laser dis-
`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 a lesser extent, by varying
`the type of vehicle, or binder, into which the pigment is
`incorporated.
`It is also possible to modify colors by
`combining fluorescent dyes with nonfiuoreseent dyes
`that selectively absorb a portion of the emission spec-
`trum. For example,
`the emission spectrum of
`the
`naphthalimide dye (type 3485) show in Fig. :3 peaks at
`5300 A, in the green. Normally this fluorescence ap—
`pears to have a yellowish—green cast due to the broad
`tail of the emission spectrum which extends into the
`yellow and red. However,
`this tail can be substan—
`tially reduced by the addition of a nonfiuorescing green
`toner such as phthalocyaninc,la which absorbs in the
`yellow and red.
`The result
`then is a tradeoff of
`brightness for the ability to limit the spectral content.
`In contrast to the many yellow and red emit-ting dyes,
`blue emitting dyes are less common. However,
`ex—
`amination of pyrclene in dilute alcoholic solutions in-
`dicates that it is blue fluorescing wheno excited by short
`wavelength blue light spch as 4579-A emission of an
`argon laser or the 4410~A emission of a cadmium laser,
`while it becomes green fiuorescing under longer wave—
`length blue excitation such as the 4880-11 line of an ar—
`gon laser.
`In addition, pigments of coumarin which
`fluoresces blue under near ultraviolet excitation are
`commercially available.13
`
`IV. Conclusion
`
`There exists a sufficiently wide range of efficient or-
`ganic and inorganic phosphors that can be excited by
`laser wavelengths ranging from the ultraviolet to green
`and that have emission spectra covering the entire
`visible. For example, a suitable combination of blue,
`green, and red emitting phosphors can be made to
`fluoresce any color desired including white when illumi-
`nated by a blue or ultraviolet 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-
`sion of a monochromatic laser source provides an attracw
`tive means for achieving white and light and multicolor
`for display system applications.
`
`'
`
`The authors acknowledge with thanks helpful dis-
`cussions with E. A. Chandross and C. V. Lundberg
`concerning organic dyes and pigments. The authors
`also thank H. W. Grodkiewicz, A. G. Dentai, and C. J.
`Schmidt for the growth and preparation of test samples
`and S. R. Williamson for assistance in experimental
`measurements.
`
`References
`
`1. c. E. Baker, IEEE Spectrum 5. 39 (December 1968).
`2. J. E. Geusic, H. J. Levinstein, S. Singh, R. G. Smith, and L.‘
`G. Van Uitert, Appl. Phys. Lett. 12, 306 (1968).
`3. L. H. Enloe, Bell System Tech. J. 46, 1479 (1967).
`4. P. Pringsheim, Fluorescence and Phosphorescence (Intersci—
`once, New York, 1949), pp. 1—10.
`5. J. D. Gould and W. L. Makous, Information Display 5,
`25 (November/December 1968).
`. Ref. 4, pp. 285—289.
`L. G. Van Uitert, J. Electrochem. Soc. 114, 1048 (1967).
`. L. G. Van Uitert and R. R. Seder), J. Chem. Phys. 36, 1289
`(1962).
`
`03740:
`
`9. G. Blasse, W. L. Wanmaker, J. W. tcr Vrugt, and A. Bril,
`Philips Res. Rep. 23, 189 (1968).
`10. G. Blasse and A. Bril, J. Chem. Phys. 47, 5139 (1967).
`11. G. Blasse and A. Bril, Appl. Phys. Lett. 11, 53 (1967).
`12. Ref. 4, pp. 594—645.
`13. Day—Gin Color Corporation, Cleveland, Ohio, Tech. Booklet
`No. 1170-A.
`'
`-
`
`14. E. G. Bobalek and W. Von Fisher, Organic Protective Coatings
`(Reinhold, New York, 1953), pp. 115—118.
`15. Ref. 4, p. 423.
`16. R. A. Ward, ”The Day-Glo' Daylight Fluorescent Color
`Specification System (Day-G10 Color Corp, Cleveland,
`Ohio).
`
`
`
`COVER
`
`This month's cover shows constant-hue and saturation loci derived from geodesic chroma-
`ticity diagram. The radii of the constant-saturation circles on the gm diagram were 20h;
`the angular separations of points were 13“/n. The constant-hue loci shown correspond to
`radii separated by 18“ in the 5"! diagram.
`
`January 1971 / Vol. 10, No. 1 / APPLIED OPTICS 153
`
`LOWES 1027, Page 6
`LOWES 1027, Page 6
`
`VIZIO EX. 1027 Page 0006
`
`VIZIO Ex. 1027 Page 0006
`
`