View Single Post
Old 04-06-2008, 12:49 PM   #7
Cocide
Newbie
 
Cocide's Avatar
 
Join Date: Apr 2008
Location: Tx
Vehicle: 96 Miata
Posts: 40
My Photos: ()
I think you miss understood the layout of the board, let me try to explain in a text drawing


if you were looking down the end of the setup, with the screen to the left, and ccfl tubes were on the top and bottom:
the display is represented with ||
a LED is an *
and = shall represent the circuit board

=
*
||
||
||
||
||
*
=



from the top, looking down on the lcd pannel:
the # in this one are the panel
once again * for a LED
and = for the board
========
*********
########
########
########
*********
========

so basically the boards would be the width of the panel by the height of the LED, seeing as that would go where the ccfl tube went it should fit.

Quote:
Since a mcd is a cd/m^2, that makes more sense now of how they are able to quote such high brightness values. I am thinking maybe you can do a simple ratio to figure out how much theoretical brightness you will get.

Brightness of LED x Area(led) = Brightness of screen x Area screen

So for a n number of leds, the brightness would be:

Brightness of Screen = n x (brightness of single led) x (area of single led) / (area of screen)

So using the leds in your link, for 100 leds and a 7 inch screen, brightness is only 63 mcd. Seems a bit low...maybe my calculations are wrong?

Well I checked the calculations based on the 'math' and for a 8.4 4:3 with 200 I got 77mcd, basically the same. The one thing that dose stand out is that I have seen it as cd/m2 not cd/m^2, I was guessing that they meant square meter, but I would think with a LED that bright those numbers have to be somewhere in the middle of the 750,000 and 77 mcds.

I do have some 1000mcd LEDs, they are not SMD so I could not use them, They are extremely bright, its almost like staring into the sun if they hit you the right way. So by comparison I would think that those are plenty bright, not to mention that most of the places I have looked will draw the LED / super bright LED line at 1000 mcd.
__________________
Planing [=====>] 90%
Coding [===>----] 50%
Interface [=>-------] 25%
Hardware [>---------] 10%
Install [-----------] 0%

Last edited by Cocide : 04-06-2008 at 01:27 PM.
Cocide is offline   Reply With Quote