At this point I shall shamelessly copy and paste a post on a weapons board at which I asked about these reflex sights.
Posted by Howedar (12.225.76.56) on July 03, 2002 at 16:56:41:
As far as I can tell, it might actually be a sight (albeit one unutilized by the braindead Federation "troops"). There seems to be a sight available today that does not appear to utilize parallax (don't ask me how, it certainly confuses me) that is not that great for distance shooting, but is useful in close-quarters combat and quick target acquisition: exactly what a phaser rifle ought to have, considering its unsuitability for anything but short-range firing.
At this point I shall shamelessly copy and paste a post on a weapons board at which I asked about these reflex sights.
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There are primarily 2 sights used by the US military that are "reflex" type red dot sights of 1x magnification.
One of them is the Trijicon "Reflex" which is a single lense sort of heads up display, the reticle is projected onto the front lens using ambient light directed through fiberoptics during the daytime and during nighttime it uses a tritium source to project light into the same aiming point so it's a totally battery free system. However because there is one lens it is somewhat prone to parralax but it is fairly minimal or goes un-noticed during most typical shooting(both eyes open combat type engagements), to properly sight the Reflex for utmost accuracy it is best to have the dot centered within the sight housing but it isn't mandatory and inside 150 yards for combat conditions where the dot rests is where the bullet is going to hit no matter where the dot seems to be in relation to the front sight or if it's centered int he sight.
The other reddot sight as used by the US military comes from Aimpoint and it is a battery powered system. It uses a series of lenses to help eliminate parallax so that no matter where the dot is within the sight what it covers is where the bullet will impact.
There is also another difference between the two sights, the Reflex uses a colored lense coating to bring out contrast between the downrange target area and the color of the dot, depending on lighting situations it can be sort of difficult to isolate the dot or to further isolate the dot the user must use a polarizing filter which if totally closed will make what is called an "occluded eye gunsight" where the sight is totally blacked out and the brain is forced to merge the red dot as seen by the sighting eye with the image of the downrange target as seen by the other eye.
The Aimpoint sights are totally clear with no tinting on the lenses so the issue of clarity when viewing the target is not at issue. It's got a variable dot intensity that can go from a lowest setting of only visible with night vision equipment all the way up to a near "bright as the sun" intensity on it's maximum setting.
The two sights are extremely fast to use giving the user a feeling almost of like they are sighting a shotgun, the gun comes up into the shoulder and as soon as you see that dot you can put it on target without having to give attention to lining up rear sights with the front sight for a proper sight picture. In a CQB environment they rule the day, if I had to pick between the two sights for close up work I actually prefer the Trijicon Reflex while if I had to shoot out to longer ranges I prefer the Aimpoint.
The Trijicon Reflex's tinting gives it the effect of a "ghost ring" sight where the blue tint of the sight makes you conscous of what's in the immediate target area of your sight and the red dot contrasts nicely against the blue, at night time with the use of a tactical light it becomes REAL obvious of the effects and I have been meaning for a LONG time to get a picture up of this effect to show what it looks like. Maybe later...
The Aimpoint with no color tint to the sight allows for more precision and detail to be seen by the user and makes it easier for the shooter to aim precisely since they aren't "fighting" with the sight to get on target.
The complete Trijicon line of sights/scopes can be found here,
http://www.trijicon-inc.com/products.html
3-4 of the sights on the page can be found within the US military: the ACOG line of scopes, Armson Occluded Eye Gunsight, the Trijicon Reflex sights, and the new Tripower sight which is probably undergoing evaluations right now.
The Aimpoint sights are located here
http://www.aimpoint.com/products/prodpres3.htm
The Aimpoint sight that was first being used on the military rifles was the CompM but now Aimpoint has improved the sight and brought out the CompM2 which has an improved circuitry that allows for much longer battery life, same basic sight though.
Here's an old picture of my Reflex when it was mounted to my Bushmaster AR15, 
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As far as I can tell, these reflex sights don't use the standard front sight of the weapon, nor do they use multiple panes in the sight itself to make use of parallax. I haven't the foggiest clue how it works, but it seems consistant with what the Federation ought to have on its phaser rifles (they certainly aren't used though).
Just something I was pondering.