1、_ SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising there
2、from, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions. Copyright 2011 SAE International All rights reserved. No part of this publication m
3、ay be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: +1 724-776-4970 (outside U
4、SA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.orgSAE values your input. To provide feedbackon this Technical Report, please visit http:/www.sae.org/technical/standards/J2739_201102SURFACEVEHICLEINFORMATIONREPORTJ2739 FEB2011 Issued 2007-01 Stabilized 2011-02 Supe
5、rseding J2739 JAN2007 Absorptive and Interference Coatings Applied on Replaceable Headlamp Bulbs RATIONALE The technical report covers technology, products, or processes which are mature and not likely to change in the foreseeable future. STABILIZED NOTICE This document has been declared “Stabilized
6、“ by the SAE Road Illumination Devices Standards Committee and will no longer be subjected to periodic reviews for currency. Users are responsible for verifying references and continued suitability of technical requirements. Newer technology may exist. Copyright SAE International Provided by IHS und
7、er license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE J2739 Stabilized FEB2011 Page 2 of 29 1. SCOPE This report investigates the use of single and multi-layer coatings on replaceable headlamp bulbs and how such coatings can affect the performance
8、of bulbs in terms of light scattering, which can contribute to glare, and spectral separation in headlamps. Tests were developed to investigate the effects of absorptive and interference (multi-layer) coatings on bulbs, and on bulbs in headlamp systems. These tests provide validation for a proposed
9、bulb color separation test, which establishes limits for spectral separation within the boundaries of SAE J578 white color requirements. The bulb color separation test provides a definitive selection criterion to identify bulbs that cause excessive light scatter (glare) and/or spectral separation in
10、 an optical system. 2. REFERENCES 2.1 Applicable Publications The following publications form a part of this specification to the extent specified herein. Unless otherwise indicated, the latest version of SAE publications shall apply. 1. Bucher, K., Holt, D., King, G., Lttgens, G., Rice, L., Schug,
11、J., Terburg, B., Visser, A. de, Woodward, R., “Investigation into the Effects of Absorptive and Interference Coatings Applied on Replaceable Headlamp Bulbs”, SAE technical publication, SP-1875, #2004-01-0802, Society of Automotive Engineers, Warrendale, PA (2004). 2. Tessnow, T., Reiners, T., Hering
12、, O., “Optical Near Field Measurements and Ray-Tracing Simulation of Coated and Uncoated Halogen Lamps for Glare Analysis”, SAE technical publication, SP-1787, #2003-01-0929, Society of Automotive Engineers, Warrendale, PA (2003). 3. ECE Economic Commission of Europe Regulation 5, http:/www.unece.or
13、g/trans/main/wp29/wp29regs.html. 4. SAE Standard J578, “Color Specification“, Society of Automotive Engineers, Warrendale, PA, 2002. 5. ASTM E 308-66, “Method for Computing the Colors of Objects by Using the CIE System”, American National Standards Institute, Inc., 25 West 43rd Street, New York, NY
14、10036-8002. Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE J2739 Stabilized FEB2011 Page 3 of 29 6. FMVSS (Federal Motor Vehicle Safety Standards) (1998) Standard 108: “Lamps, reflective devices
15、, and associated equipment”. In: Code of Federal Regulations, 49CFR571, Washington, D.C.: Office of the Federal Register. 7. Terburg, B.P., et al. “Review of Color Coated Bulb Test Methods and Data“, report to United Nations Economic Commission for Europes Working Party on Lighting and Light Signali
16、ng, report #GRE44/inf.1 (2000). 8. ECE Economic Commission of Europe Regulation 8, http:/www.unece.org/trans/main/wp29/wp29regs.html. 9. ECE Economic Commission of Europe Regulation 20, http:/www.unece.org/trans/main/wp29/wp29regs.html. 3. INTRODUCTION The introduction and sale of tinted replaceable
17、 headlamp bulbs first appeared in the late 1990s. The lamps initially sold used standard replaceable capsules, which were coated with interference (multi-layer) coatings to produce a “HID color”. A survey of bulbs that were being sold in the aftermarket showed that some of the bulbs did not meet per
18、formance specifications for light output or wattage. Another characteristic of the multiple-layer interference coating was that the light output was separated into bands of color which depending on the viewing angle could range from reddish to greenish to blue-ish white. The color separation was sti
19、ll noticeable when placed in a headlamp. An oncoming vehicle could produce a change of color that could confuse drivers or more typically produced a higher level of offending glare. Existing tests and regulations did not anticipate tinted headlamp bulbs. To address this issue an international group
20、of engineers from the bulb manufacturers under auspices of SAE assembled a task force to investigate the effects and recommend the appropriate test methods for governing their design and use. 4. BACKGROUND AND TEST METHODS The initial investigation of color separation focused on the investigation of
21、 the color separation as it pertains to the light output from the bulb. The typical US replaceable bulbs were used in the investigation. These bulbs were ANSI 9004, 9005, 9006 and 9007. After the first round of tests were completed and a proposed method was documented, the scope of the investigation
22、 was broadened to include the consideration of the effects of glare from the bulb in a lighting system such as a headlamp. For this reason the testing was separated into Round 1 Testing and Round 2 Testing. Round 1 testing initially investigated two types of methods: The Bulb Haze Method and Bulb Co
23、lor Separation test. A color separation test standard was later adopted into European regulations and a US version was developed simultaneously. These methods are described below. Round 2 testing investigated four potential test methods: the Bulb Haze Method, a Reference Reflector Method, Bulb Optic
24、al Properties and Near Field Imaging. Of these the Reference Reflector method and the Near Field Imaging were used. Near field imaging is widely accepted method in the study of the optical performance of bulbs 2. 5. PHYSICS OF COLOR SEPARATION In understanding what causes spectral (color) separation
25、 in certain types of coated bulbs, one has to investigate the phenomena that occur when white light from a tungsten filament in a halogen bulb traverses the glass bulb wall of the coated bulb. A coated bulb has the outside bulb wall coated with a thin film that filters light either through absorptio
26、n, or through interference. In the latter case the thin film is a multi layer film. In either case of filter technologies the purpose of the filter is to achieve a more bluish white color of light, either by absorbing some light in the yellow wavelengths (absorption coating), or by reflecting yellow
27、 and red light out of the spectrum (interference coating). The process of light traversing the coating is illustrated in Figure 1. Note that the schematics in Figure 1 are simplified to show the processes that occur in the coating layer only. Specular reflection and transmission on the surfaces of g
28、lass bulb wall have not been graphically depicted. Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE J2739 Stabilized FEB2011 Page 4 of 29 Figure 1a shows transmission of white light (shown as comp
29、osed of its spectral components) through the wall of a bulb that has been coated with an absorption coating. In this case specular transmission is the dominant process, and the overall transmitted color is bluish white. Absorption Coating Interference Coatingredfilamentspecularreflexcoatingbulb wall
30、bluishwhiteyellowwhitelightgreenfilamentcoatingbulb wallbluishwhitewhitespeculartransmittancebluishwhite(a)(b)FIGURE 1 -TRANSMISSION OF WHITE LIGHT (SHOWN AS COMPOSED OF ITS SPECTRAL COMPONENTS) THROUGH THE WALL OF A BULB THAT HAS BEEN COATED WITH (A): AN ABSORPTION COATING. IN THIS CASE SPECULAR TR
31、ANSMISSION IS THE DOMINANT PROCESS. (B): AN INTERFERENCE COATING. IN THIS CASE SPECULAR TRANSMISSION AND SPECULAR REFLECTION OCCUR. YELLOW AND RED COMPONENTS OF THE LIGHT ARE REFLECTED BACK INTO THE INNER PART OF THE BULB. Figure 1b shows transmission of white through the wall of a bulb that has bee
32、n coated with an interference coating. In this case specular transmission and specular reflection occur. Yellow and red components of the light are reflected back into the inner part of the bulb. The light will appear bluish white, light green, reddish, or another color different from bluish white d
33、ependent on the angle that the bulb is viewed from. In regard to this it is worth noting that, when subjected to spherical photometry, bulbs using both technologies will show an integrated color of bluish white. The yellow and red components of the light that are reflected towards the inside of the
34、interference-coated bulb generate virtual images of the filament in the respective colors. The virtual images are out of focus for the optical system design and give rise to color separation and glare when the bulb is used in an optical system (headlamp). Figure 2 shows an example of the virtual ima
35、ges generated in a H7 bulb with interference coating. viewing direction1st order virtual image2nd order virtual imagefilamentFIGURE 2 - PROJECTION ONTO THE WALL FOR A H7 BULB WITH INTERFERENCE COATING. THE FIRST (YELLOWISH) AND SECOND (REDDISH) VIRTUAL IMAGES ARE PRESENT FOR THE INTERFERENCE COATED
36、BULB, BUT NOT FOR THE CLEAR AND ABSORPTION COATED BULB. A SKETCH OF THE VIEWING DIRECTION IS INCLUDED. Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE J2739 Stabilized FEB2011 Page 5 of 29 6. TES
37、TING 6.1 Round 1 Testing 6.1.1 Bulb Haze Method The bulb haze method is based on the assumption that glare is the end result of light scattering from bulb coatings. Measuring light scattering from the bulb will give information on the potential that a coating can create glare. The measurement method
38、 is based on determining the brightness of light scattered from the bulb wall relative to the brightness of the filament. No widely accepted measurement method existed. The method described in this work was adapted from an ECE method used to measure haze caused by abrasion 3. In the bulb haze (glare
39、) measurement the filament is aligned such that the broad view is projected on a plane. The filament is energized and focussed on a detector that has a stripe that blocks the filament. Readings are taken with and without the light block. The haze or glare level is the ratio of light scattered from t
40、he bulb to the total light. The acceptable values could be confirmed by using the reference reflector to evaluate the effects on the system. Figure 3 shows a schematic of the measurement system used. FIGURE 3 - BULB HAZE MEASUREMENT SYSTEM. AN ACHROMATIC LENS IS USED TO CREATE THE IMAGE. TABLE 1 - B
41、ULB HAZE MEASUREMENT RESULTS Tracking Bulb Coating Measured BlockingNumber Type Type Filament Filter No Filter % Ratio3 S904Absorption Low Beam 0. 183 18.23 1. 05 S904Absorption Low Beam0. 178 14.61 1. 21 S904Absorption Low Beam 0. 241 19.29 1. 24 S904Absorption Low Beam 0. 216 16.16 1. 32 C904Mult
42、i-Lay er Low Bea m 0. 249 9.41 2. 613 E5 9004Mult i-Lay er Low Bea m 0. 454 9.08 5. 014 E6 9004Mult i-Lay er Low Bea m0. 552 8.59 6. 411 P3 9005Absorption - 0.084 14.19 0.612 P4 9005Absorption - 0.079 12.71 0.68 C905Mult i-Lay er - 0. 149 11.54 1. 39 P3 9006Absorption - 0.062 11.91 0.510 P4 9006Abso
43、rption - 0.071 9.92 0.77 C906Mult i-Lay er - 0.104 7.3 1.46 C907Mult i-Lay er Low Bea m 0. 173 8.16 2. 1Measurments made at 12.80 volts 7-Dec-99Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE J27
44、39 Stabilized FEB2011 Page 6 of 29 Data from a wide range of bulbs with absorption and multiple layer interference coatings were taken in order to make a comparison of the performance of the different coating technologies possible. Table 1 gives a summary of the results that were obtained with this
45、method. The last column in the table lists the ratio between the light measured with the blocking filter to the light measured without the blocking filter. This is assumed to be proportional to the ratio of light scattered from the bulb to the total light. As can be observed, the ratio is considerab
46、ly higher for the coated bulbs with multi-layer technology. This implies increased light scattering for those bulb types. Although these results are encouraging, this method has several limits. The alignment of the optical system is difficult due to the small image size. In addition to that measurem
47、ents are sensitive to alignment errors. Furthermore, the method requires different striped plates for each bulb type and each filament design. Lastly, the data cannot be evaluated using alternate methods. 6.1.2 BULB COLOR SEPARATION TEST In the bulb color separation test chromaticity readings of an
48、energized bare blue bulb are taken in directions that fall within a conical volume of revolution, where the axis of revolution is parallel to the bulb axis. Figure 4a illustrates the measurement arrangement. Within the conical volume, a measurement grid can be defined, for instance the one that was used in this study where the polar angle . and azimuthal angle both vary over a range of 30. Figure 4b shows the grid of measurement directions that is constructed within the . and intervals Detector ReceivingAngle 5-15Centerline ofDetector shall movewithin and = 2 x 30= 2 x
