Larger LEDs?

Is is possible to increase the light output of a LED by making them larger in size?

See the thread from Cyclops942 on the 2nd page of posts. He asked this recently.

Click here for a direct link to that thread.

Cant they just make a couple of diodes in one LED fixture to increase the light output? The thing seems small enough to fit more than one in there.

There are superbright LEDs with more than one diode chip inside, although larger than normal size. Trouble is you get the same problem as trying to focus a cluster of LEDs with a flashlight lens- the light comes from many individual points inside but is all focussed through just one lens so the result is a bit odd. See the first LED of this bit of Craig`s LED site...

<center> http://ledmuseum.home.att.net/ledred.htm </center>
I don`t know how much these cost from Roithner Laserteknik but it`s probably a lot (might say on their web site?), and since the LED dies inside are series connected they will want quite a high voltage (over 12 I`d say )to get them to work, so these are probably not that good for a flashlight. I don`t know what other colours you can get either besides a slightly frightening IR one, probably not white though.
Ideally you want just one die at the focal point of the lens and the new Philips/Agilent ones do have a larger die inside than normal (eg Nichia) LEDs so I`ve been told.