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 I.,ibrary 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`bibliographical and processing information for many historical documents.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 'Journal of the
`Illuminating Engineering Society, Volume 6, Issue 2 (January 1977), which includes
`the paper Improved Color Rendition In High Pressure Mercury Va1vor Lamps I by
`Mary Hoffinan.
`
`4. Mr. Richard F. Moncrief requested information about Journal of tile Illuminating
`Engineering Society, Volume 6, Issue 2 (January 1977)- 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 21, 11!}77.
`
`Sworn to before me this
`13th day of December 2016
`
`4j1~f_e,~
`
`Not~ Public
`
`LYNDS! R. PRIGNON
`Notary Public, State of New York
`No.01PR6069103
`Qualified in Tompkins County 1 q
`Commission Expires January 22, 20 ~
`
`VIZIO 1024
`
`

`
`Volurhe B/Numben 2
`
`danuany 1977 ('33,
`
`;he Illuminating Engineering Society
`
`Lighting in the logging and sawmill industries
`
`Jltraviolet radiation—considerations in interior lighting design
`
`mproved color rendition in high pressure mercury vapor lamps
`
`the design of safety-colors
`
`iungsten-halogen lamp dosed with tin tetraiodide
`
`an automated high-speed photometer
`
`Specification of an ESI rating in interior spaces
`
`‘iiscussion of previously published papers
`
`VIZIO 1024
`
`VIZIO 1024
`
`

`
`Volume 6/Number 2
`
`January 1977
`
`of the Illuminating Engineering Society
`
`Lighting in the logging and sawmill industries
`Technical Committee Report
`
`Ultraviolet radiation-considerations In Interior lighting design
`R. E. Levin, G. R. Spears, G. W. Clark and E. D. Bickford
`
`Improved color rendition in high pressure mercury vapor lamps
`Mary V. Hoffman
`
`The design of safety-colors
`W. A. Thornton
`
`Tungsten-halogen lamp dosed with tin tetralodide
`A. D. Kulkarni, J. Martin and H. G. Sell
`
`An automated high-speed photometer
`L. C. Snyder and P. E. Westlake
`
`Recommended practice for the specification of an ESI rating in
`interior spaces when specific task locations are unknown
`Technical Committee Report
`
`67
`
`80
`
`89
`
`92
`
`100
`
`105
`
`111
`
`Dlscussi~n of previously published papers
`
`124
`
`QUarterly in the United States of America by the Illuminating Engineering Society of North America, 345
`St., New York, N.Y. 10017. Copyright, Illuminating Engineering Society of North America, 1977. Sec(cid:173)
`postage paid at New York, N.Y. and additional mailing offices. This publication is indexed regularly
`P.!lllllln&Ari,on Index, Inc., and is available on microfilm from University Microfilm, Ann Arbor, Mich. 48106.
`rates: $25.00 for feu annual issues, plus extra postage to all coootries in which second-class postage
`apply. Single copies: $2.5Q to members; $6.25 to nonmembers. Editorial Office, 345 East 47th St.,
`N.Y. 10017. Printing Office, Easton, Pa . .
`
`Clifford L. Forbes Jr. Editor
`
`Jack F. Christensen Associate Editor
`
`John E. Kaufman Technical Director
`
`Howard Haynes Engineering Assistant
`
`C. L. Crouch Director of Research IERI
`
`VIZIO 1024
`
`

`
`Improved color rendition
`in high pressure mercury vapor lamps
`
`"
`Mary V. Hoffman
`
`The addition of Y 3AI50 12:Ce to the group of phosphors suitabie for color
`correcting the mercury discharge lamp· provides. for improving the color
`rendering Index without a lumen loss. By altering the cerium content in the
`formulation, the absorption and brightness can be adjusted to its optimum
`value in the lamp.
`
`The ideal in color rendition of a high pressure mer(cid:173)
`cury discharge lamp has been the subject of several
`recent papers, in which simulated spectral distribu(cid:173)
`tions have been created by the addition or subtrac(cid:173)
`tion of spectral energy. 1•2 This can be done to obtain
`lamps of selected color temperatures, with various
`combinations of real and simulated phosphor emis(cid:173)
`sions. The optimization of the luminous efficiency
`can be calculated in the same manner. One study has
`shown that the addition of emission at 620 nanome(cid:173)
`ters to the Hg discharge is near the optimum for color
`rendition, but that for lamps with color temperature
`of 4000 to 3000 kelvins, it is necessary to remove some
`of the Hg discharge in the blue. For luminosity, ad(cid:173)
`dition of emission near 590 nanometers is need-
`. ed.2,3
`Among the existing phosphors meeting the tem(cid:173)
`perature and stability requirements of the mercury
`discharge lamps, only Y V04:Eu and Y(VP)04:Eu
`phosphors (YVP) supply emission at the necessary
`spectral region, with the main peak at 618 nanome(cid:173)
`ters. They do not provide absorption of the blue Hg
`lines in sufficient &mount or emission in the high ·
`1\.uninous region. Filtering of the blue can be obtained
`by the addition of a pigment or of a phosphor which
`also acts as a pigment. The phosphor magnesium
`fluogermanate activated with manganese (MG) is the
`only suitable red emitter with appreciable absorption
`of the blue lines, but ·since the emission is at 650 to
`660 nanometers, the luminosity is not en4anced by
`A paper presented at the Ann.ual IES Conference, August 29
`through September 2, 1976, Cleveland, Ohio. AUTHOR: General
`Electric Company, Cleveland, Ohio.
`
`this substitution. Combinations of these two phos(cid:173)
`phors can be used, as described by Rokosz, et al. 4
`We have found another phosphor , cerium-acti(cid:173)
`vated yttrium aluminate garnet (YAG:Ce) which is
`useful in improving color rendition by absorbing the
`blue Hg radiation and also adds to the total emission
`of the lamp by converting this blue radiation into
`emission centered at 560 nanometers. It can be
`combined with the Y(VP)04:Eu emission, effectively
`changing the color of the lamp.
`Lamps prepared with blends ofYAG:Ce and YVP
`phosphors show the shift in color points from below
`the black body to, on, or above the locus, depending
`on the proportions used. Typical color points are
`shown in Fig. 1 for a warm color corrected lamp. The
`
`Figure 1. Color shifts with increasing Y AG:Ce hi ·v(VP)
`04:Eu.
`
`3500 K 3300 K
`
`X
`
`JOURNAL OF IES I JANUARY 1977
`
`89
`
`VIZIO 1024
`
`

`
`color shift is due largely to the absorption of the 436
`nanometer Hg line, which is filtered by about 40
`percent with 15 percent YAG in the blend. The lu(cid:173)
`minosity of the lamps remains about the same for
`four lamp colors shown. This is due to the .efficient
`conversion of the 436 Hg line into visible emission.
`These data are summarized in Table l.
`The actual color points obtained can be varied by
`the amount of phosphor used on the lamp as well as
`the proportion of Y AG:Ce in the blend. It can also be
`
`varied by u~ing the blend over a pre-coat, as de(cid:173)
`scribed by Rokosz, et al. 4 The pre-coat acts as a re(cid:173)
`flector for both uitraviolet and the blue radiation,
`allowing better utilization of the Hg radiation by the
`phosphors. With the Y AG:Ce present, the reflection
`of the blue radiation increases its effect both as a
`pigment and as a phosphor.
`The YAG:Ce phosphor, which was developed for
`its emission characteristics under cathode ray exci(cid:173)
`tation5·6 is strongly absorbing in the blue, as shown
`
`1.0
`
`0.9
`
`UJ
`
`0 z 0.8
`~
`0
`UJ 0.7
`...J
`LL.
`UJ
`Q:
`
`0.6
`
`UJ
`(/)
`::::>
`LL. 0.5
`LL.
`0
`
`0.4
`
`0.3
`
`>-
`1-
`.Cii z
`
`UJ
`1-
`~
`
`UJ
`· >
`i=
`ct
`...J
`UJ
`
`Q: ~ 330 340 350 360
`
`nm
`
`Figure 2. Diffuse Reflectance curve, (Y 2.92s Ceo.o1sh
`AI5012•
`
`~20 430 440 450 460 470 480
`. W~VELENGTH, n m
`Figure 3. Excitation curve: detected wavelength-511
`nanometers.
`
`Figure 4. Emission curve: excitation wavelength-436
`nanometers.
`
`Figure 5. Emission intensity vs cerium content~ measured
`at 25° C and 300° C. Excitation wavelength-436 nm.
`
`/ - -
`1--at 25°C
`I
`I
`I
`f,
`1/
`II
`If
`
`- a t 300°C
`
`>(cid:173)
`t-
`en z w
`1-z
`
`>
`
`~ .en z w
`
`1-
`~
`w
`>
`ti
`..J w
`0:::
`
`480 520 560 600 640 680 720
`WAVELENGTH, n m
`
`X
`
`90
`
`JOURNAL OF IES I JANUARY 1977
`
`VIZIO 1024
`
`

`
`Table 1-Lamp data:YAG:Ce with Y(VP)04 :Eu
`
`Percent 100-hour
`lm/w
`YAG:Ce
`
`X
`
`y
`
`0
`5
`10
`15
`
`51.5
`52.1
`50.7
`51.3
`
`.408
`.411
`.420
`.426
`
`.384
`.394
`.403
`.411
`
`CRI
`
`45
`
`51
`
`4. F. Rokosz, J. W. Sausville, and J. Van Broekhoven, "Incan(cid:173)
`descent lamp color with high-intensity discharge lamps," JOUR(cid:173)
`NAL OF THE ILLUMINATING ENGINEERING SociETY, Vol. 3, No.
`1, October 1973, p. 95.
`5. G. Blasse and A. Bril, "A new phosphor for flying-spot cath(cid:173)
`ode-ray tubes for color television: yellow-emitting Y 3Al50 12:Ce,"
`Applied Physics Letters, Vol. II, No.2, July 15,1967, p. 53 .
`6. W. W. Holloway, Jr. and M. Kestigian, "Optical properties of
`cerium-activated garnet crystals," Journal of the Optical Society
`of America, Vol. 59, No.1, January 1969, p. 60 .
`
`DISCUSSION .
`
`W. A. THORNTON:* The high pressure mercury vapor lamp is
`in need of all the kindly attention it can get. This welcome paper
`brings better lamp performance closer. It performs a service by
`bringing another useful phosphor into the very limited line-up of
`luminescent materials that can endure the operating conditions
`in this lamp. The new phosphor has the useful property of con(cid:173)
`verting undesired blue-violet arc emission to desired green light,
`which tends to improve both color rendering and output. Does the
`increase in Color Rendering Index (CRI), as 15 percent of the new
`phosphor is added, represent a real visual improvement in color
`rendering of real objects and scenes? As to the proposed addition
`of yellow wavelengths near 590 nanoeters "for good lumen output
`in the lamp system," we believe that such addition would harm
`color rendering more than it would improve lumen output. The
`usefulness of the new YAG:Ce phosphor is, we believe, due to the
`fact (see Fig. 4) that it contributes green light and red light; that
`it also contributes yellow light is a disadvantage. The Soules and
`Maier study (see Reference 2) makes clear that peak lumen output
`by use of yellow light is accompanied by color .rendering index of
`-20. Reference 1 ascribes poor color rendering to yellow emitting
`phosphors. Has the author any prospect of an efficient phosphor
`emitting a narrow band near 490 nanometers, which, according
`to the same references, can help raise CRI further?
`
`AUTHO.R: t The true test of improved color rendition always rests
`on a subjective visual evaluation, especially in a system such as this
`one, with about ten percent calculated change in CRI. No sys(cid:173)
`tematic evaluation of this lamp system has been made, but the
`general appearances have been favorable.
`The emission contribution of Y AG:Ce (if present as the only
`phosphor) would defmitely result in a lower CRI. The Soules and
`Maier paper points to a system that closely approximates a pure
`Y AG:Ce lamp. It has a CRI of 23. The usefulness of the YAG:Ce
`lies in its ability to absorb the 436-nm Hg line to the extent suffi(cid:173)
`cient to improve the CRI, and supply enough emission to con(cid:173)
`tribute to the lumen level, at a relatively low weight percent.
`The Soules and Maier paper ascribes the CRI of -20 to a system
`containing a narrow band emission at 580 nanometers, when
`combined with bluer line e~ission, but shows that- when Eu+3
`emission is present the CRI cannot fall that low.
`·
`
`*Westinghouse Electric Corporation, Bloomfield, New Jersey.
`t The author wishes to acknowledge the help of Dr. T. F. Soules
`for numerous discussions and E. Homonnay for the testing in
`lamps·.
`
`•
`by the diffuse reflectance curve (see Fig. 2), and is
`also excited by this radiation. This absorption is into
`the 5d state of the cerium, which in this crystal
`structure, lies in an unusual position. Cerium usually
`absorbs in the ultraviolet and emits in the near ul(cid:173)
`traviolet or in the blue. The Y AG:Ce phosphor is not
`excited by 254 nanometers and only weakly by 365
`nanometers from the Hg arc. The excitation spectra
`(See Fig. 3) shows the very strong dependence of· the
`emission intensity on the 436-nm Hg radiation.
`The emission of the phosphor is in a band peaking
`at about 540 nanomete·rs at 25 ° C shifting to about
`560 nanometers at 300° C (See Fig. 4). This is at the
`maximum eye sensitivity and close to the calculated
`peak of 590 nm for good lumen output in the sys(cid:173)
`·
`tem.
`As with most phosphors, the specific conditions of
`the lamp determine its applicability, and the com(cid:173)
`position can often be altered according to its use. In
`the YAG:Ce phosphor, the cerium concentration is
`the critical factor. Both the absorption at .436 na(cid:173)
`nometers and the emission intensity increase with
`the cerium concentration with the brightness
`reaching a maximum at about . one- to two-atom
`percent and the absorption at about three-atom
`percent when measured at 25° C. At the temperature
`of operation of the lamp, the phosphor is less effi(cid:173)
`cient, and brightness measurements made at 300° C
`show that lower cerium concentrations are desirable.
`As shown in Fig. 5, a rather narrow range of cerium
`content must be maintained for the best conversion
`of 436 radiation to emission at 560 nm in the lamp.
`Referenc~s
`l. J. J. Opstelten, D. Radielovic and W. L. Wanmaker, "The
`choice and evaluation of phosphors for application to lamps with
`improved color rendition," Journal of the Electrochemical So(cid:173)
`ciety, Vol. 120, No. 10, October 1973, p. 1400.
`2. T. F. Soules and. M.A. Maier, "Optimized spectral power dis-
`. tributions for mercury vapor lamps," Journal of the Electro(cid:173)
`chemical Society, Vol. 121, No.3, March 1974, p. 407.
`3. H. lvey, "Color and efficiency of fluorescent and fluoro(cid:173)
`rescent-mercury lamps," Journal of' the Optical Society ol
`America, Vol. 62, 1972, p. 814.
`·
`
`Information for authors
`
`The JOURNAL OF THE IES Is published quarterly by the Illuminating Engi(cid:173)
`neering Society of North America. Manuscripts should be sent to the edHor,
`345 East 47th Street, New York, N. Y. 10017. All manuscripts are subject
`to .the review of the Papers Committee of the IES.
`
`JOURNAL OF IES I JANUARY 1977
`
`91
`
`VIZIO 1024