Interpretation ID: nht92-2.10

DATE: November 23, 1992

FROM: T. Kouchi -- Director & General Manager, Automotive Equipment, Development & Administration Department, Stanley Electric Co., Ltd.

TO: Paul Jackson Rice -- Chief Counsel, NHTSA

TITLE: None

ATTACHMT: Attached to letter dated 12/30/92 from Paul J. Rice to T. Kouchi (A40; Std. 108)

TEXT:

We are investigating the development of automotive tail & stop lamps using light emitting diodes (LEDs) as light sources.

We have already asked you about Center High-Mounted Stop Lamp (CHMSL) using LEDs and have received your letter of January 9, 1986, in which you answered that such type of CHMSL would be acceptable when it complies with the photometric requirements and provides replaceability of light sources (S4.1.41(e)) specified in FMVSS No. 108.

From your answer, we consider that LEDs can be used in tail & stop lamps.

Now we would like to ask you additional questions as follows:

(1) Is it possible for us to group LED tail & stop lamps into three categories in terms of the number of lighted sections to determine applicable photometric requirements, as specified in paragraph 4.1.5.1 of SAE J1389 JUN83?

(2) Where the above view is acceptable, could we consider the number of lighted section as "one" in case of a lamp which contains three LED arrays arranged as shown in the attached drawing, if the circumferenc of three projected luminous areas does not exceed 150mm both in horizontal and vertical dimensions?

(3) Where the number of lighted section is determined as "one" in the above, can we locate "the geometric center of the illuminated area" at the point marked in the attached drawing, according to paragraph 2.6 of SAE J1389 JUN83?

We would be very pleased if you kindly inform us of your points of view for the above(1)-(3).

(Drawing omitted.)