On Fri, 20 Oct 2023 23:45:29 +1100, Chris Jones
<lugnut808@spam.yahoo.com> wrote:
>On 20/10/2023 7:37 pm, Martin Brown wrote:
>> A breakthrough in low voltage blue LEDs announced recently this manages
>> to produce 2.7eV blue photons from an applied voltage of 1.47v! It is
>> the chemical equivalent of a Cockcroft-Walton voltage doubler.
>>
>> https://www.sciencedaily.com/releases/2023/09/230920110657.htm
>>
>> Or for more details the Nature paper (may be behind a paywall)
>>
>> https://www.nature.com/articles/s41467-023-41208-7
>>
>> It is a very cunning design and chemistry.
>>
>
>
>Damnit.
>
>I was very pleased when I had found out that the marketing/design people
>for a product that I designed had tried to swap out the LEDs from red to
>blue in some misguided attempt to make the product look like a tacky
>teenager's car with underbody lighting from the mid-2000s, and had been
>thwarted by the ~2.5V (IIRC) supply voltage of the microcontroller.
>
>I shall have to prepare a new strategy to prevent anyone from defacing
>my designs and impunging my dignity.
>
In the pioneer days of Cree SiC blue LEDs, we used a blue LED as VME
module bus access indicator. It looked nice at 50 mA. As blue LEDs got
better, customers were whining about being blinded. I think we run
them around 1 mA now.
Blue can be annoying.
Reply by Jan Panteltje●October 20, 20232023-10-20
On a sunny day (Fri, 20 Oct 2023 09:37:04 +0100) it happened Martin Brown
<'''newspam'''@nonad.co.uk> wrote in <ugte7h$vajs$4@dont-email.me>:
> On 20/10/2023 7:37 pm, Martin Brown wrote:
>> A breakthrough in low voltage blue LEDs announced recently this manages
>> to produce 2.7eV blue photons from an applied voltage of 1.47v! It is
>> the chemical equivalent of a Cockcroft-Walton voltage doubler.
>>
>> https://www.sciencedaily.com/releases/2023/09/230920110657.htm
>>
>> Or for more details the Nature paper (may be behind a paywall)
>>
>> https://www.nature.com/articles/s41467-023-41208-7
>>
>> It is a very cunning design and chemistry.
>>
>
>
> Damnit.
>
> I was very pleased when I had found out that the marketing/design people
> for a product that I designed had tried to swap out the LEDs from red to
> blue in some misguided attempt to make the product look like a tacky
> teenager's car with underbody lighting from the mid-2000s, and had been
> thwarted by the ~2.5V (IIRC) supply voltage of the microcontroller.
>
> I shall have to prepare a new strategy to prevent anyone from defacing
> my designs and impunging my dignity.
>
>
>
;)
Fortunately it only works for OLEDs.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC /
Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics
Reply by Chris Jones●October 20, 20232023-10-20
On 20/10/2023 7:37 pm, Martin Brown wrote:
> A breakthrough in low voltage blue LEDs announced recently this manages
> to produce 2.7eV blue photons from an applied voltage of 1.47v! It is
> the chemical equivalent of a Cockcroft-Walton voltage doubler.
>
> https://www.sciencedaily.com/releases/2023/09/230920110657.htm
>
> Or for more details the Nature paper (may be behind a paywall)
>
> https://www.nature.com/articles/s41467-023-41208-7
>
> It is a very cunning design and chemistry.
>
Damnit.
I was very pleased when I had found out that the marketing/design people
for a product that I designed had tried to swap out the LEDs from red to
blue in some misguided attempt to make the product look like a tacky
teenager's car with underbody lighting from the mid-2000s, and had been
thwarted by the ~2.5V (IIRC) supply voltage of the microcontroller.
I shall have to prepare a new strategy to prevent anyone from defacing
my designs and impunging my dignity.
Reply by Phil Hobbs●October 20, 20232023-10-20
Martin Brown <'''newspam'''@nonad.co.uk> wrote:
> A breakthrough in low voltage blue LEDs announced recently this manages
> to produce 2.7eV blue photons from an applied voltage of 1.47v! It is
> the chemical equivalent of a Cockcroft-Walton voltage doubler.
>
> https://www.sciencedaily.com/releases/2023/09/230920110657.htm
>
> Or for more details the Nature paper (may be behind a paywall)
>
> https://www.nature.com/articles/s41467-023-41208-7
>
> It is a very cunning design and chemistry.
>
Fun. I’ll have to try digging up a copy of the original paper.
Could conceivably be important if the quantum efficiency is decent and the
drive circuitry isn’t too horrible. (The QE obviously can’t exceed 50%.)
The Science Daily article claims the usual sorts of stuff about battery
voltage being this fundamental limitation, as though there were no such
things as SMPSes.
It’s far from clear that it’s some huge win needing 2x the current at half
the voltage, especially since the power output is bound to be quadratic in
the drive current.
If the intermediate state is long-lived, that might not be so awful.
Fun, anyway!
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC /
Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics