[R-390] Re: LED Yellowing Agent

[Michael Murphy]

Hmm,

Perhaps dunking the LED in yellow 5-minute epoxy would work.

Mike WB2UID

----- Original Message -----
From: "Tom Norris" <r390a at bellsouth.net>
To: <R-390 at mailman.qth.net>
Sent: Wednesday, July 07, 2004 3:22 PM
Subject: [R-390] OT: LED tail lights, white LED physics


> According to USDOT and such, they are supposed
> to be annoying. Apparently the instant on feature
> cuts as much as a quarter second off the response
> time that would otherwise be spent getting an
> incandescent filament lit to full brightness. A
> quarter second is a long time as accident response
> goes, and can mean the difference in avoiding an
> rear-end or sliding under the vehicle in front of you.
>
> That being said, as far as LEDs for running lights,
> the red is too "spectrally pure" and is way hard on my
> eyes too.
>
> I tend to agree on the white LEDs being somewhat
> "harsh" since they tend to have a blue shift to then.
> Indeed all should, the white leD is manufactured
> from a blue or uv led die, which is then doped with a
> mixed spectrum phosphor-like material. The effect is
> not unlike that of a florescent lamp. The harshness
> comes from the blue or uv/blue that is emitted as
> the phosphor doesn't do much to block it.
>
> Tom
>
>
> >James Miller wrote:
> >
> >>  I prefer the "soft" on and off times of filament lamps over the
> >>  instantaneous on-off of LEDs.
> >>  Ever drive behind a car with those obnoxious LED brake lights,
> >>  especially the Cadillacs?, They flash on instantly... no soft warm up
time.
> >>  It's grating on the nerves.
> >
> >Or new "large cars" (18 wheelers). EXTREMELY annoying....!!! We
> >just returned from a 3967 mile trip out east to visit relatives. Traffic
> >around Minneapolis was chaotic.
> >
> >Ken W7EKB
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