L.E.D. Signal and Marking Lighting Devices
This SAE Recommended Practice applies to functions of motor vehicle signaling and marking lighting devices which use light emitting diodes (L.E.D.’s) as light sources. This report provides test methods, requirements, and guidelines applicable to the special characteristics of L.E.D. lighting devices. This Recommended Practice is in addition to those required for devices designed with incandescent light sources. This report is intended to be a guide to standard practice and is subject to change to reflect additional experience and technical advances.
Rationale: Current definition of photometric stability and commonly used procedure for testing LED functions greatly penalizes LED lamps in a production environment. Changes recommended to J1889 will expedite production testing without compromising accuracy. This version will describe a procedure to expedite testing but will allow testing to former J1889 methods.
Section 2 updated to meet SAE standards
Section 3.2 – LED definition changed to match J387
Section 3.7 – Removed
Section 3.8 - Clarified Photometric Stability definition and harmonized with J2650. New definition allows photometric data to be taken within the 15 minute stability box, instead of after. To maintain good accuracy during photometry the allowed stability drift is set at +3%. Since section 3.7 was removed, photometric stability will be re-numbered to section 3.7
Section 5.1.1 - Removed extra performance requirement of photometric check for lamps not fully functional. This is covered in J575 and J2139
Section 5.1.5 Renumbered to accommodate changes. Clarified test point to use for ratio measurement because some functions do not have significant intensity at H-V
Section 188.8.131.52 - Clarifies use of SAE J1330
Section 184.108.40.206 - Adds statement lamps must be stabilized for test
Section 220.127.116.11 - Was added to provide procedure for testing all lamps at stabilization.
Section 5.1.6 - Removed warpage as it is covered in lamp level testing
Section 6.1.1 Removed extra performance requirement of photometric check for lamps not fully functional. This is covered in J575 and J2139
Section 6.1.5 Simplified requirement definition and included the option to flash function that flash during operation.
Section 18.104.22.168 Removed steady burning language, included in 6.1.5
Section 22.214.171.124 Removed intermittent burning language, included in 6.1.5
Section 126.96.36.199 Re-numbered to 188.8.131.52
Section 6.1.6 Removed warpage requirement as it is covered in lamp level testing
Section 7.2 was added to provide a method for predetermining photometric stability.
Section 7.2.1 Reference to section 3.8 was changed to Section 3.7 to reflect numbering change
Section 8.1 - Removed
Section 8.2 - Numbering changed to 8.1
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