Re: [NTLK] Backlight fun-replacing backlight

From: Johannes Wolf (mp2100_at_mail-gw.estec.esa.int)
Date: Wed Aug 06 2003 - 07:23:08 PDT


I can only tell you that the german Newton backlight project tried hell of a
lot to find an optimum solution and they ended up with a green foil.
It is also important to know that the converter in the Newt is optimised for
the original foil and you do not necessary achieve good results with other
foils in terms of brightness versus power consumption.
Except you are going to modify the converter circuit.
But unfortunately we do not have the circuit diagram.

Marco experimented with white backlight as well and his main problem was to
establish a reliable electrical contact to the foil. He also reported that
the contrast is less with white background foil because the original foil is
also matched with the optical properties of the LCD display. With a white
background foil you have something like grey instead of black.

Cheers
Johannes

> -----Original Message-----
> From: newtontalk-bounce_at_newtontalk.net
> [mailto:newtontalk-bounce_at_newtontalk.net]On Behalf Of Damien Batstone
> Sent: Wednesday, August 06, 2003 3:35 PM
> To: newtontalk_at_newtontalk.net
> Subject: Re: [NTLK] Backlight fun-replacing backlight

> That's perhaps because they're using a blue-green backlight, rather than
> the white one in Gert's. According to RS, it is about 50% brighter at an
> equivalent freq/voltage than other colours:
>
> Brightness @ 100V, 400Hz
> Blue-green 73cd/m2
> Other colours 50cd/m2
>
> You can look at Item 267-8706 on the RS components website
> (www.rs-components.co.uk) The current specs on that page are a little
> scary. Maybe the Newton transformer is more efficient. I don't know why
> Gert's hums less with a white backlight.
>
> I guess everyone is probably using these Seiko EL sheets, and
> according to
> Marco the Newton transformer is 600hz/110V.
>
> Does anyone have comments on whether white/lower light or green-blue/high
> light is better for usability?
>
> Regards,
>
> Damien

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