focus led's
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Chris M.
Flashlight Enthusiast
Re: focus led\'s
The trouble with LEDs is that they have their own built in lens which focusses their light into a directional beam- typically 20 degrees total. Sticking a LED in the middle of a reflector does have some beam-concentrating effect as there is still some light shining out of the sides that escapes the lens, but usually the effect is minimal. The Trek-50 "CC Extreme" is an example of such a flashlight- (don`t have one but have read reviews) apparently it is focussable but since the light that is being focussed is less than probably 1/4 of the total light output from the LED, the focussing effect is mostly lost to the beam coming straight from the LED.
A couple of ways to get around this and make narrower beams. One is to use an external focussing lens which goes in front of the LED, narrowing its beam. This works quite well- PAL-Onestars use a regular 5mm LED and a lens, other Pals use special wide beam angle surface mount LEDs and a lens to focus the light into a narrow beam, but it is a little odd looking. Still shines further than a bare 5mm LED.
Another way is to modify the LED so it loses its integral beam-concentrating lens instead emmitting light all round like a normal bulb. Then this can be put into a reflector and actually does focuss the light into a narrow beam. This is what LEDcorp does in their unique range of products. The Turtlelite-1 and Aluminum flashlight use a specially ground LED. Turtlelite gives a very narrow beam that shines quite far. The Aluminum one is focussable like a Maglite to give narrow spot to wide flood, but the wider settings have unpleasent rings that can`t really be avoided in the design.
This focussing works fine with a single LED but if you want brighter, you normally have to use more LEDs- and using a reflector or lens over multiple LEDs simply won`t work right unless there are individual reflectors for each LED. Current LED technology doesn`t really lend itsself to being focussed and the manufacturers don`t show any signs of making "normal" LEDs with narrow beams (usually it comes out all wrong anyway like those really narrow blue-green 20600mcd ones).
The new Luxeon Star LEDs show some promise- a single LED emmitting the light of maybe 10 normal ones (at normal power levels). The external lense it can be supplied with gives a smooth beam of about 12 degrees total but it is fixed. I reckon it won`t be long though before flashlight manufacturers start tying out their own lens designs to make LED lights with narrower brighter-looking beams, that can finally compete with small incandescents.
The trouble with LEDs is that they have their own built in lens which focusses their light into a directional beam- typically 20 degrees total. Sticking a LED in the middle of a reflector does have some beam-concentrating effect as there is still some light shining out of the sides that escapes the lens, but usually the effect is minimal. The Trek-50 "CC Extreme" is an example of such a flashlight- (don`t have one but have read reviews) apparently it is focussable but since the light that is being focussed is less than probably 1/4 of the total light output from the LED, the focussing effect is mostly lost to the beam coming straight from the LED.
A couple of ways to get around this and make narrower beams. One is to use an external focussing lens which goes in front of the LED, narrowing its beam. This works quite well- PAL-Onestars use a regular 5mm LED and a lens, other Pals use special wide beam angle surface mount LEDs and a lens to focus the light into a narrow beam, but it is a little odd looking. Still shines further than a bare 5mm LED.
Another way is to modify the LED so it loses its integral beam-concentrating lens instead emmitting light all round like a normal bulb. Then this can be put into a reflector and actually does focuss the light into a narrow beam. This is what LEDcorp does in their unique range of products. The Turtlelite-1 and Aluminum flashlight use a specially ground LED. Turtlelite gives a very narrow beam that shines quite far. The Aluminum one is focussable like a Maglite to give narrow spot to wide flood, but the wider settings have unpleasent rings that can`t really be avoided in the design.
This focussing works fine with a single LED but if you want brighter, you normally have to use more LEDs- and using a reflector or lens over multiple LEDs simply won`t work right unless there are individual reflectors for each LED. Current LED technology doesn`t really lend itsself to being focussed and the manufacturers don`t show any signs of making "normal" LEDs with narrow beams (usually it comes out all wrong anyway like those really narrow blue-green 20600mcd ones).
The new Luxeon Star LEDs show some promise- a single LED emmitting the light of maybe 10 normal ones (at normal power levels). The external lense it can be supplied with gives a smooth beam of about 12 degrees total but it is fixed. I reckon it won`t be long though before flashlight manufacturers start tying out their own lens designs to make LED lights with narrower brighter-looking beams, that can finally compete with small incandescents.
Re: focus led\'s
The point is that a reflector has no real effect on the light of an LED. LED gives a dispersed light so that a reflector can not work in its traditional way. Two examples of the this point: LEDs have two practical advantages - you can read by it comfortably, as it does not give glare off of white paper (normally you would have to hold the beam off center to read by flashlight), and in winter conditions, the LED does not cause snow glare. It does not reflect.
This is also the reason that the LED cannot "throw" a beam for any distance. The Lens is the only option. A lens in this instance can only really function with one LED. There is a focal point in the lens - multiple LEDs would never hit the focal point and you end up with the same issue, a dispersed light shooting in multiple directions with no focus.
LEDs are definitely neato, but I would say that they really are not terribly practical for most people. They can be absolutley brillaint for the right conditions and I can attest that at night in the wintery alps - they can't be beat.
The point is that a reflector has no real effect on the light of an LED. LED gives a dispersed light so that a reflector can not work in its traditional way. Two examples of the this point: LEDs have two practical advantages - you can read by it comfortably, as it does not give glare off of white paper (normally you would have to hold the beam off center to read by flashlight), and in winter conditions, the LED does not cause snow glare. It does not reflect.
This is also the reason that the LED cannot "throw" a beam for any distance. The Lens is the only option. A lens in this instance can only really function with one LED. There is a focal point in the lens - multiple LEDs would never hit the focal point and you end up with the same issue, a dispersed light shooting in multiple directions with no focus.
LEDs are definitely neato, but I would say that they really are not terribly practical for most people. They can be absolutley brillaint for the right conditions and I can attest that at night in the wintery alps - they can't be beat.
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