I have tried a search on this subject, but quite honestly the forum is so big now, that it takes ages to sift through the threads bought up. This might be old hash .
Let me just run this past you guys....
I made a soccer scoreboard with 7x5 displays last year , Using the SAA1064 chip , which gave a 50% duty cycle , for max output from each LED. I am now making some more boards using the MAX7219 driver.
I have arranged it this time with 5 columns across and 7 high .
This means I can set up in the register to limit to 5 columns, and skip the other 3, giving more brightness , 20 % duty cycle, but still down on the 50% duty cycle of last years
The LEDs I am using this year are more than twice the output of last years ones, so I should be back on track with the actual apparent brightness of last years project.
Now I have a request for a similar sign twice the digit size ( 4 times the area ) but I have realised that I can put 2 red LEDS in series in place of the previous one ( each has 1v9 voltage drop ) and the chip should be able to supply Imax to both LEDs in series at 3v9
So in theory I can get twice the light output per column, using twice the number of LEDs, with the chip now running cooler, as it doesn't have to get rid of the extra ( 5 - 1.9 v )
But since now I am saving the power dissipation in the chip, perhaps I can pulse the LEDs with twice the current as before ? Giving me twice the light output for the same digit ? ( OK at double the supply current, but there is no such thing as a free meal ! )
How does this sound ?
If you are not upsizing, you could tilt every other LED by half the viewing angle and get the same intensity as with one LED.