[Avodah] LED "tealights" for Shabbos candles

[Akiva Miller]

Back in 2006 (Avodah 17:93), in a discussion about telephones and
microphones on Shabbos, I cited Rav Moshe Heinemann (of the Star-K;
in "Guide to Halachos" by Nachman Schachter, published by Feldheim,
pp 29-30):
> Activating any electrical device to generate either heat or
> light or increasing the setting on an electrical device to
> generate more heat or light is prohibited because of the
> Melacha D'oraisa of Mav'ir. Examples include intentionally
> 1) activating a heating pad, 2) activating a light, 3)
> increasing the setting on a dimmer switch and 4) increasing
> the setting on an electric blanket.

> However, activating a device that provides unnecessary heat
> or light, e.g. a phone with a lighted dial in an illuminated
> room, is prohibited as a Melachah D'rabbanan.

I am now wondering how LED light fit into that. In the current thread,
R' Micha Berger wrote:
> Incandescent light bulbs provide the light of a hot metal
> filament....

> An LED is a semiconductor where atoms in it emit light when
> their energy level drops due to electrons jumping across a
> transmission in how the semiconductor is "doped". There is no
> heating. Nothing remotely similar to the concept of aish as
> per havarah, mechabeh or bishul. I have even a harder time
> picturing the appropriateness of "me'orei ha'eish" on them.

So here's my question: If an LED light, as RMB has explained it, does
*not* constitute "aish", does that mean that using one on Shabbos would be
"only" a Melacha D'Rabanan (according to Rav Heinemann)?

Did we once discuss those tubes which are filled with chemicals which emit
light (but NO heat) when the chemicals are mixed? Are those "aish" or not?

(See examples at http://en.wikipedia.org/wiki/Glow_stick)

Akiva Miller