4-i

CHAPTER 4. SCREENING ANALYSIS 

TABLE OF CONTENTS 

4.1 INTRODUCTION ........................................................................................................... 4-1

4.2 SCREENED OUT TECHNOLOGIES ............................................................................ 4-2

4.2.1 General Service Fluorescent Lamps .................................................................... 4-2

4.2.1.1 Multi-Photon Phosphors .............................................................. 4-2

4.2.2 Incandescent Reflector Lamps ............................................................................. 4-2

4.2.2.1 Novel Filament Materials ............................................................ 4-2

4.2.2.2 Microcavity Filaments ................................................................. 4-3

4.2.2.3 Crystallite Filament Coatings ...................................................... 4-3

4.2.2.4 High Reflectance Filament Supports ........................................... 4-3

4.2.2.5 Non-Tungsten-Halogen Regenerative Cycles.............................. 4-4

4.2.2.6 Higher Efficiency Gold Reflector Coatings ................................. 4-4

4.2.2.7 Permanent Infrared Reflector Coating Shroud ............................ 4-4

4.2.2.8 Infrared Phosphor Glass Coating ................................................. 4-5

4.2.2.9 Ultraviolet Phosphor Glass Coating............................................. 4-5

4.2.2.10 Corner Reflectors .................................................................... 4-5

4.2.2.11 Electron Stimulated Luminescence ......................................... 4-5

4.3 SUMMARY OF TECHNOLOGY OPTIONS SCREENED OUT .................................. 4-6

4.4 REMAINING TECHNOLOGIES ................................................................................... 4-6

4.4.1 General Service Fluorescent Lamp Design Options ............................................ 4-6

4.4.2 Incandescent Reflector Lamp Design Options .................................................... 4-7

REFERENCES ............................................................................................................................ 4-8

LIST OF TABLES 

Table 4.3.1 GSFL Technology Options Screened Out of the Analysis ........................... 4-6

Table 4.3.2 IRL Technology Options Screened Out of the Analysis .............................. 4-6
4-1

CHAPTER 4. SCREENING ANALYSIS 

4.1 INTRODUCTION 

This chapter discusses the U.S. Department of Energy’s (DOE) screening analysis 

of the technology options identified for general service fluorescent lamps (GSFLs) and 

incandescent reflector lamps (IRLs). As discussed in chapter 3 of this preliminary 

technical support document (TSD), DOE consults with industry, technical experts, and 

other interested parties in developing a list of technology options for consideration. The 

purpose of the screening analysis is to evaluate the list of options and determine which to 

consider further and which to screen out. 

Section 325(o)(2) of the Energy Policy and Conservation Act (EPCA) provides 

that any new or revised standard must be designed to achieve the maximum improvement 

in energy efficiency that is determined to be technologically feasible and economically 

justified. (42 U.S.C. 6295(o)(2)) In view of the EPCA requirements for determining 

whether a standard is technologically feasible and economically justified, Appendix A to 

Subpart C of Title 10, Code of Federal Regulations (CFR), Part 430, “Procedures, 

Interpretations, and Policies for Consideration of New or Revised Energy Conservation 

Standards for Consumer Products” (the Process Rule) sets forth procedures to guide DOE 

in its consideration and promulgation of new or revised efficiency standards. These 

procedures elaborate on the statutory criteria provided in 42 U.S.C. 6295(o) and, in part, 

eliminate problematic technologies early in the process of prescribing or amending an 

energy efficiency standard. In particular, sections 4(b)(4) and 5(b) of the Process Rule 

provide guidance to DOE for determining which technology options are unsuitable for 

further consideration: 

1. Technological feasibility. DOE will consider technologies incorporated in 

commercially available products or in working prototypes to be technologically 

feasible. 

2. Practicability to manufacture, install, and service. If mass production of a 

technology and reliable installation and servicing of the technology could be 

achieved on the scale necessary to serve the relevant market at the time the 

standard requires compliance, then DOE will consider that technology practicable 

to manufacture, install, and service. 

3. Adverse impacts on product utility or product availability. If DOE determines 

a technology would have significant adverse impact on the utility of the product 

to significant subgroups of consumers, or would result in the unavailability of any 

covered product type with performance characteristics (including reliability), 

features, sizes, capacities, and volumes that are substantially the same as products 

generally available in the United States at the time, it will not further consider this 

technology. 
4-2

4. Adverse impacts on health or safety. If DOE determines that a technology will 

have significant adverse impacts on health or safety, it will not further consider 

this technology. 

Section 4.2 of this chapter discusses the technology options DOE screened out 

from further consideration. Section 4.3 summarizes those options. Section 4.4 lists the 

remaining technology options not screened out and considered as design options in this 

preliminary analysis. The market and technology assessment (see chapter 3 of this 

preliminary technical support document [TSD]) discusses in detail all technology options 

analyzed in this preliminary analysis. 

4.2 SCREENED OUT TECHNOLOGIES 

This section addresses the technologies that DOE screened out, having considered 

the following four factors: (1) technological feasibility; (2) practicability to manufacture, 

install, and service; (3) adverse impacts on product utility or product availability; and (4) 

adverse impacts on health or safety. 

4.2.1 General Service Fluorescent Lamps 

4.2.1.1 Multi-Photon Phosphors 

Theoretically, the use of multi-photon phosphors, or quantum-splitting phosphors, 

could significantly improve lamp efficacy. By emitting more than one visible photon for 

each ultraviolet photon, a lamp would be able to emit more light for the same amount of 

power. Researchers at Georgia Tech were issued a patent for an oxide-based phosphor 

doped with praseodymium and atoms of at least one activator that produces two visible 

light photons from a single ultraviolet light photon.1 However, development of this 

technology for use in lighting products remains in the research phase and DOE is 

unaware of any prototypes or commercialized products that incorporate multi-photon 

phosphors.2Further, researchers have identified technical drawbacks to this technology 

such as light color output, color stability, and phosphor lifetime.3Thus, DOE screened 

out this technology option based on the first criterion, technological feasibility, and will 

not consider multi-photon phosphors as a design option for improving the efficacy of 

GSFLs. 

4.2.2 Incandescent Reflector Lamps 

4.2.2.1 Novel Filament Materials 

Novel filament materials such as nitrides and carbides have the potential to 

improve lamp efficacy by emitting more light in the visible spectrum at a given 

temperature than traditional tungsten filaments. Because patents on such filaments exist,4

5 DOE believes that this technology option is technologically feasible. However, DOE is 

unaware of any commercially available lamps that incorporate such filaments and 

therefore, it is unclear that this technology is practicable to manufacture on the scale 

necessary to serve the relevant market at this time. Furthermore, DOE understands that 

issues, such as prohibitive brittleness of the filament, limit implementation of this 
4-3

technology and could potentially negatively impact its utility to consumers. Therefore, 

DOE screened out novel filament materials on the basis of the second criterion, 

practicability to manufacture, and the third criterion, potential impacts on utility to 

consumers, and will not consider novel filament materials as a design option for 

improving the efficacy of IRLs. 

4.2.2.2 Microcavity Filaments 

By fabricating microcavities on the incandescent lamp filament, it is theoretically 

possible to increase a lamp’s emissivity, and therefore its efficacy. Sandia National 

Laboratories researchers examined microcavity resonance in a tungsten photonic lattice6

and DOE found multiple patents referencing this technology.7 8 Because prototypes of 

microcavity filaments do exist, DOE determined that this technology option is 

technologically feasible. However, DOE is unaware of any commercially available lamps 

that incorporate microcavity filaments and therefore, it is unclear that this technology is 

practicable to manufacture on the scale necessary to serve the relevant market at this 

time. Additionally, research indicates that materials patterned at the submicron level may 

experience problems with stability.9Therefore, DOE screened out microcavity filaments 

based on the second criterion, practicability to manufacture, and third criterion, adverse 

impacts on consumer utility, and will not consider filaments with microcavities as a 

design option for improving the efficacy of IRLs. 

4.2.2.3 Crystallite Filament Coatings 

DOE screened out crystallite filament coatings, which are oxide-covered micron 

or submicron crystallites composed of thorium, tantalum, or niobium. These coatings can 

be used to increase the light emissivity of a lamp’s filament. Because patents on such 

filament coatings exist,10 DOE believes that this technology option is technologically 

feasible. However, DOE is unaware of any commercially available lamps that incorporate 

crystallite filament coatings. Further, using crystallite filament coatings may require 

additional manufacturing techniques, such as chemical vapor deposition. DOE 

understands that these techniques are not in use in the mass production of IRLs. Hence, 

DOE does not consider this a technology that is practicable to manufacture on the scale 

necessary to serve the relevant market at this time. Therefore, DOE screened out this 

option based on the second criterion, practicability to manufacture, and will not consider 

crystallite filament coatings as a design option for improving the efficacy of IRLs. 

4.2.2.4 High Reflectance Filament Supports 

Filament supports can have a reflective face that redirects light to a filament, 

another reflector, or radially outward. The filament supports could also include grooves, a 

coating with a high emissivity to increase heat dissipation, or be formed of a porous 

ceramic material to increase efficiency. However, halogen capsules have not incorporated 

these structures due to potential efficacy losses. Because this technology is still in the 

patent application stage,11 DOE screened out high reflectance filament supports based on 

the first criterion, technological feasibility. Thus, DOE will not consider high reflectance 

filament supports as a design option for improving the efficacy of IRLs. 
4-4

4.2.2.5 Non-Tungsten-Halogen Regenerative Cycles 

The regenerative cycle of filament evaporation and redeposition can be used to 

greatly increase the life of an incandescent lamp and improve lumen maintenance. The 

filament can burn at a higher temperature than conventional incandescent lamps while 

maintaining a useful service life. DOE understands that other regenerative cycles also 

may be possible for non-tungsten filament materials and patents indicate they are 

technologically feasible.12 However, as noted in section 4.2.2.1, DOE has screened out 

the use of novel filament materials on the basis of the second and third screening criteria. 

Because use of the non-tungsten-halogen regenerative cycles would depend on 

incorporating a non-tungsten filament, DOE screened out such cycles from consideration 

based on the same two criteria, practicability to manufacture and potential adverse 

impacts on utility to consumer. Therefore, DOE will not consider non-tungsten-halogen 

regenerative cycles as a design option for improving the efficacy of IRLs. 

4.2.2.6 Higher Efficiency Gold Reflector Coatings 

Gold is one type of higher efficiency reflector coating that is extremely reflective 

and has the potential to increase the amount of directed light, and therefore the efficacy, 

of IRLs. Because a patent on the use of gold reflector coatings exists,13 14 DOE has 

determined that this technology option is technologically feasible. However, DOE found 

that gold reflectivity diminishes at and below blue-green wavelengths, which may 

decrease the color quality of light,15 thereby impacting product utility. Further, gold 

reflector coatings have thus far been used mainly in lamps that produce infrared and nearinfrared light (e.g., heat lamps or lamps intended to change the color of light, such as 

those used for photography purposes). Therefore, use of these reflector coatings may not 

be suitable for general lighting applications. Hence, DOE screened out high efficiency 

gold reflector coatings based on the third criterion, adverse impact on product utility, and 

will not consider higher efficiency gold reflector coatings as a design option for 

improving the efficacy of IRLs. However, DOE did not screen out other higher efficiency 

reflector coatings, such as aluminum and silver, because they do not have an adverse 

impact on product utility and meet DOE’s screening criteria. Therefore, DOE considers 

higher efficiency reflector coatings, with the exception of gold reflector coatings, as 

design options for improving the efficacy of IRLs. 

4.2.2.7 Permanent Infrared Reflector Coating Shroud 

Infrared reflector coatings on halogen capsules allow visible light to pass through 

the glass envelope, while reflecting the infrared energy back to the filament. As this 

coating must be replaced whenever the lamp reaches end of life, it represents a significant 

component of manufacturing costs. A permanent shroud with infrared reflector coating 

would therefore increase efficiency while also reducing manufacturing costs. However, 

because this technology is still in the patent application stage,16 DOE screened out 

permanent infrared reflector coating shrouds based on the first criterion, technological 

feasibility. Thus, DOE will not consider permanent infrared reflector coating shrouds as a 

design option for improving the efficacy of IRLs. 
4-5

4.2.2.8 Infrared Phosphor Glass Coating 

When used as a coating on the bulb surface, infrared phosphors harvest the 

emitted infrared energy and convert it to visible light, potentially increasing lamp 

efficacy. Because patents on such infrared phosphor coatings exist,17 DOE has 

determined that this technology option is technologically feasible. However, DOE is 

unaware of commercially available lamps that incorporate infrared phosphor glass 

coatings. Hence, DOE does not consider this a technology that is practicable to 

manufacture on the scale necessary to serve the relevant market at this time. Therefore, 

DOE screened out this option based on the second criterion, practicability to 

manufacture, and will not consider infrared phosphor coatings as a design option for 

improving the efficacy of IRLs. 

4.2.2.9 Ultraviolet Phosphor Glass Coating 

Similar to infrared phosphor glass coating, when used as a coating on the bulb 

surface, ultraviolet phosphors absorb ultraviolet radiation and convert it to visible light. 

Because patents on the incorporation of ultraviolet phosphor glass coatings exist, DOE 

has determined that this technology option is technologically feasible.18 19 However, 

DOE is unaware of commercially available lamps that use ultraviolet phosphor glass 

coatings. Hence, DOE does not consider this a technology that is practicable to 

manufacture on the scale necessary to serve the relevant market at this time. Therefore, 

DOE screened out this option based on the second criterion, practicability to 

manufacture, and will not consider ultraviolet phosphor glass coatings as a design option 

for improving the efficacy of IRLs. 

4.2.2.10 Corner Reflectors 

Corner reflectors incorporated into the cover glass of IRLs have the potential to 

increase lamp efficacy by redirecting infrared radiation back onto the filament. Because 

patents on trihedral and cubic corner reflectors exist,20 21 DOE believes that this 

technology option is technologically feasible. However, DOE is unaware of any 

commercially available lamp that incorporates corner reflectors. Further, using corner 

reflectors, which entails an additional disc requiring external fabrication and installation 

in the lamp, may necessitate manufacturing techniques not currently available for mass 

production. Hence, DOE does not consider this a technology that is practicable to 

manufacture on the scale necessary to serve the relevant market at this time. Therefore, 

DOE screened out this option based on the second criterion, practicability to 

manufacture, and will not consider corner reflectors as a design option for improving the 

efficacy of IRLs. 

4.2.2.11 Electron Stimulated Luminescence 

When struck by the electrons thermally ejected from a lamp’s filament, 

cathodoluminescent phosphors emit visible light. Because a patent on the use of electron 

stimulated luminescence exists,22 DOE has determined that this technology option is 

technologically feasible. However, DOE is unaware of any commercially available lamps 

that incorporate electron stimulated luminescence. Hence, DOE does not consider this a 

technology that is practicable to manufacture on the scale necessary to serve the relevant 
4-6

market at this time. Therefore, DOE screened out this technology option on the basis of 

the second criterion, practicability to manufacture, and will not consider electron 

stimulated luminescence as a design option for improving the efficacy of IRLs. 

4.3 SUMMARY OF TECHNOLOGY OPTIONS SCREENED OUT 

The following tables summarize the technology options DOE is considering 

screening out and the associated screening criteria. 

Table 4.3.1 GSFL Technology Options Screened Out of the Analysis

Design Option Excluded Screening Criteria

Multi-Photon Phosphors Technological feasibility

Table 4.3.2 IRL Technology Options Screened Out of the Analysis

Design Option Excluded Screening Criteria

Novel Filament Materials Practicability to manufacture, install, and service

Product utility to consumers

Microcavity Filaments Practicability to manufacture, install, and service

Product utility to consumers

Crystallite Filament Coatings Practicability to manufacture, install, and service

High Reflectance Filament Supports Technological feasibility

Non-Tungsten-Halogen Regenerative Cycles Practicability to manufacture, install, and service

Product utility to consumers

Higher Efficiency Gold Reflector Coatings Product utility to consumers

Permanent Infrared Reflector Coating Shroud Technological feasibility

Infrared Phosphor Glass Coating Practicability to manufacture, install, and service

Ultraviolet Phosphor Glass Coating Practicability to manufacture, install, and service

Corner Reflectors Practicability to manufacture, install, and service

Electron Stimulated Luminescence Practicability to manufacture, install, and service

4.4 REMAINING TECHNOLOGIES

After screening out those technologies in accordance with the policies set forth in 

10 CFR Part 430, Subpart C, Appendix A, (4)(a)(4) and 5(b), DOE is considering the 

design options in the following list as viable means for improving efficacy. These design 

options are being utilized in commercially available lamps and have demonstrated that 

they are technologically feasible, practicable to manufacture, install, and service, and do 

not result in adverse impacts on product utility/availability or health and safety. The 

market and technology assessment (see chapter 3 of this TSD) provides a detailed 

description of these design options. 

4.4.1 General Service Fluorescent Lamp Design Options 

 Highly Emissive Electrode Coatings 

 Higher Efficiency Lamp Fill Gas Composition 

 Higher Efficiency Phosphors 

 Glass Coatings 

 Higher Efficiency Lamp Diameter 
4-7

4.4.2 Incandescent Reflector Lamp Design Options 

 Higher Temperature Operation 

 Thinner Filaments 

 Efficient Filament Placement 

 Efficient Filament Orientation 

 Efficient Filament Coiling 

 Higher Efficiency Inert Fill Gas 

 Higher Pressure Tungsten-Halogen Lamps 

 Infrared Glass Coatings 

 Higher Efficiency Reflector Coatings (with the exception of gold reflector 

coatings) 

 Integrally Ballasted Low Voltage Lamps 

 DOE will consider these options in the engineering analysis as a viable means for 

improving lamp efficacy. 
4-8

REFERENCES 

1 Do, Young-rag (Seoul, KR); Park, Do-hyung (Suwon-city, KR); Park, Woun-jhang 

(Boulder, CO, US); Summers, Christopher J. (Dunwoody, GA, US); Yang, Hong-guen 

(Suwon-City, KR). (2003). U.S. Patent No. 6669867.Washington, DC: U.S. Patent and 

Trademark Office. 

2 U.S. Department of Energy Office of Building Technologies. U.S. Lighting Market 

Characterization, Volume II: Energy Efficient Lighting Technology Options. September,

2005. (Last accessed October 24, 2012).

< http://apps1.eere.energy.gov/buildings/publications/pdfs/ssl/ee_lighting_vol2.pdf>

3

Scholand, Michael. (2012). Max Tech and Beyond: Fluorescent Lamps. Lawrence 

Berkeley National Laboratory. LBNL Paper LBNL-5403E. (Last accessed October 22, 

2012) <http://escholarship.org/uc/item/9569025t> 

4 Van Thyne, Ray J., inventor; 1992 Sep. 15. Incandescent lamp filament incorporating 

hafnium. United States patent 5,148,080. 

5

Johansen, H. A. et al., inventor; 1968 Oct. 8. Incandescent lamp with a refractory metal 

carbide filament. United States patent 3,405,328. 

6

 Ibid. 

7

Jaffe, Steven et al., inventor; 1999 Sep. 21. Incandescent microcavity lightsource having 

filament spaced from reflector at node of wave emitted. United States patent 5,955,839. 

8

 Liu, Xinbing et al., inventor; 2006 May 9. Method for apparatus for forming discrete 

microcavities in a filament wire using microparticles. United States patent 7,040,130.

9 U.S. Department of Energy Office of Building Technologies. U.S. Lighting Market 

Characterization, Volume II: Energy Efficient Lighting Technology Options. September, 

2005. (Last accessed October 24, 2012). 

<http://apps1.eere.energy.gov/buildings/publications/pdfs/ssl/ee_lighting_vol2.pdf> 

10 Bigio, Laurence et al., inventor; 1995 Feb. 14. Incandescent lamp filament with surface 

crystallites and method of formation. United States patent 5,389,853 

11 Cunningham, David W., inventor; 2012 Aug. 28. Incandescent lamp incorporating 

reflective filament supports and method for making it. United States patent 8,253,309 B2. 

12 Van Thyne, Ray J., inventor; 1992 Sep. 15. Incandescent lamp filament incorporating 

hafnium. United States patent 5,148,080. 
4-9

13 Anderson, Norman C. et al., inventor; 1971 Nov. 9. Gold-coated reflector. United 

States patent 3,618,193. 

14 Walsh, Peter J. et al., inventor; 1988 Mar. 1. Energy-eficient incandescent reflector 

lamp. United States patent 4,728,848. 

15 Anderson, Norman C. et al., inventor; 1971 Nov. 9. Gold-coated reflector. United 

States patent 3.618,193. 

16 Cunningham, David W., inventor; 2012 Sep. 18. Incandescent illumination system 

incorporating an infrared-reflective shroud. United States patent 8,267,547 B2.

17 Vincent Jr., Charles, inventor; 1973 Nov. 20. Solid state lamp having visible-emitting 

phosphor at edge of infrared-emitting element. United States patent 3,774,086. 

18 Thorington, Luke, inventor; 1960 Jan. 5. Electric lamp. United States patent 2,920,222 

19 Patton, R.J., et al., inventor; 1992 June 2. Fluorescent incandescent lamp. United States 

patent 5,118,985 

20 Walsh, Peter J., inventor; 1989 Mar. 28. Corner cube array for use in incandescent 

lamps. United States patent 4,816,714. 

21 Nilssen, Ole K., inventor; 1986 Sep. 16. Incandescent lamp with dichroic trihedral 

corner reflectors. United States patent 4,612,473. 

22 Thorington, Luke, inventor; 1956 Aug. 14. Combination light source. United States 

patent 2,759,119.