Interpretation ID: nht93-1.44

DATE: February 22, 1993

FROM: A. L. Bragg -- Laboratory Manager, Truck-Lite Co., Inc.

TO: Paul Jackson Rice -- Chief Council, U.S. Department of Transportation, NHTSA

COPYEE: R. Kotsi; D. Gerringer; B. VanRiper; T. Kouchi

TITLE: Subject: Letter of Interpretation to Mr. T. Kouchi at Stanley Electric Co. Ltd. Re: Grouping of light emitting diodes into three or more lighting sections. Response dated December 30, 1992 from Mr. Paul Jackson Rice

ATTACHMT: Attached to letter dated 3-24-93 from John Womack to A. L. Bragg (A40; Std. 108); Also attached to letter dated 12-30-92 from Paul Jackson Rice to T. Kouchi (A40; Std. 108); Also attached to letter dated 11-23-92 from T. Kouchi to Paul Jackson Rice (OCC 8081)

TEXT: We read your response to Mr. Kouchi with interest. While we certainly agree that SAE J1889 is not incorporated into standard 108, we feel that present standards, such as J586 and J588 do allow the manufacturer to include several lighted section of lens area which may be separated by opaque or non -emitting lens areas. There are numerous examples of rear automotive lights where the light emitting area is intentionally divided by decorative strips or sections.

With this in mind, we would see no reason why the three sections shown in the attached drawing of Mr. Kouchi's letter could not act in concert to perform a single photometric function, that is, as a single compartment light. Could you comment further regarding this?

You also noted that "each of the lighted areas would constitute a three section device because it contains three or more LED's." Because of the relatively low output of an individual LED, almost every lighting device would certainly contain several LED's working together to perform a function. Your response seems to equate individual LED's with lighted sections.

If we understand your letter of interpretation correctly, it creates several problems. One of these you have alluded to in the same letter where the comment is made that a three section or compartment device could result in "glare in the eyes of the following driver." Another "problem" which would result would be the increased cost and complexity of lighting devices incorporating diodes.

It is possible that this is a problem in semantics. We would be most appreciative of any comments or clarification you might offer on the above.