Design flaws? The LED in flashlights

xdes

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Most of the led lights have the led unit (the led on a small pcb) in the reflector without any "cover", leaving the led unit bare, so we can see the whole pcb. Like in this picture:

2h4c3zt.jpg


It is just not aesthetical. Especially in smaller reflector size. However, there are some manufacturers which make it nice, good looking. Like this:

qn4v7l.jpg

2zg6pza.jpg



I think all manufacturers should do like this. All it requires is a small plastic ring (black or metal) around the LED dome + glue. What is your thoughts about this? Why is that?

You buy a good looking flashlight, everything is perfect and then you see this led naked. :(
 

shane45_1911

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It does not bother me in the least, if I see some of the pcb.

As long as the LED is centred in the reflector, I could care less about aesthetics. I don't find the visibility of the pcb to be "less attractive" anyway. YMMV.
 
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mn_doggie

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I really hate the "yellowish" color, too. I want it to be more of a blue color.

I guess I'm just gonna have to limit my purchases from now on...:shakehead

(Why should I care if there is some pretty trim blocking the heat flow off the pc board. I expect to replace all my flashlights on a regular basis, anyway. Aesthetics over function is the key.....)
 
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lightmyway

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The flashlight manufacturers don,t design the leds so they have to work around the design,some of the leds have a ring around the emmitter so that makes some easier to make them look nicer,most of the newer leds don,t have the ring but they put out more lumens.If you get a light with a deep reflector its not as noticeable..
 

dss_777

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If your intended use is staring into the business end of a flashlight, you're doing it wrong. :)
 

bansuri

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I like seeing some of the guts as long as it doesn't affect the output.
Honestly, if the emitter area looked like a Borg ship with no change to the beam I'd be ecstatic.
Fortunately the reviews and literature for lights will usually show you what the emitter area looks like so you won't get something that you find unappealing.
 

xdes

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Well. I understand that it is not important for some guys. Maybe it is just me. I like "perfection" (i know, there is no such thing as perfect...), and when it comes to flashlight i can't help noticing this.

I mean why do the manufacturers care about the flashlight design so much and not care about this? The design is pointless. A bare metal tube would do the job as flashlight body. (i know there is heat dissipation and for that it has to be fins on the head, etc but you know what i am talking about. The whole flashlight design.) I accept it is a minor issue.


I thought you flashaholics care about this too. The overall look of the light.


The business end. Yeah, that was funny, :) But when i clean the glass on my light or just look at it (turned off), i always think about this: why not cover the pcb? Yes, i always stare at the business end of the light when it is off. Just for fun.
(kidding. or not?)
 

shao.fu.tzer

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The way I look at it, just do what works... If the performance isn't affected by the exposed PCB, it shouldn't be an issue. That being said, a form fitting isolation disk is a cheap way to not only make it look better but also protect the circuitry at bit, as well.

Shao
 

xdes

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That being said, a form fitting isolation disk is a cheap way to not only make it look better but also protect the circuitry at bit, as well.

Shao
I would do that if i could disassemble the head. Too bad it is well glued. (fenix)
 

easilyled

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Has it occurred to the OP that some of us like the industrial look of the PCB and think it looks nicer than a plastic or rubber disc surrounding the led?

Some of the most expensive watches show working parts inside deliberately. Others that are not expensive (like Swatch) also do this sometimes as a design statement.
 

geckoblink

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Well. I understand that it is not important for some guys. Maybe it is just me. I like "perfection" (i know, there is no such thing as perfect...), and when it comes to flashlight i can't help noticing this.

I mean why do the manufacturers care about the flashlight design so much and not care about this? The design is pointless. A bare metal tube would do the job as flashlight body. (i know there is heat dissipation and for that it has to be fins on the head, etc but you know what i am talking about. The whole flashlight design.) I accept it is a minor issue.


I thought you flashaholics care about this too. The overall look of the light.


The business end. Yeah, that was funny, :) But when i clean the glass on my light or just look at it (turned off), i always think about this: why not cover the pcb? Yes, i always stare at the business end of the light when it is off. Just for fun.
(kidding. or not?)
Well, to be fair I get a little bummed when the led isn't centered perfectly even though the beam is. But it's like my-slice-of-pizza-has-one-less-pepperoni-than-yours kind of bummed. Not enough for me to wrench apart a bezel :D
 

flashflood

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There is no glue made by man that he cannot teareth asunder.

Aye, but also there be no glue made by man that, having been toreth asunder, can be put backeth together without looking like Lindsey Lohan after a bender.

Regarding the LED/PCB look, I see your point, but personally kind of like it. I would welcome some sort of LED collar only if it did not diminish brightness or hinder heat dissipation at all. And if it actually helps with either of those, then by all means, bring it on.
 
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Thefo

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If you look-up the white paper data for a modern emitter like an XPG-R5 then you'll see that Cree specifically refer to the PCB as the thermal pad and even state that a thermocouple be placed as close to this pad as possible for accurate measurements. The seems to indicate that the area surrounding the dome gets pretty hot so why cover it up (with something non conductive) and risk damaging the dome of the emitter. The OP's second photo has an older Cree XRE emitter which had a bigger dome that usually filled in the gap around the reflector housing so that's kind of an apples to oranges comparison.

My 2 cents
 

Lynx_Arc

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I really hate the "yellowish" color, too. I want it to be more of a blue color.

I guess I'm just gonna have to limit my purchases from now on...:shakehead

(Why should I care if there is some pretty trim blocking the heat flow off the pc board. I expect to replace all my flashlights on a regular basis, anyway. Aesthetics over function is the key.....)

Tough luck on the yellowish color if you want it to put out white light. White LEDs are actually blue LEDs with a yellowish phospor "coating" that essentially turns the blue to white. The one way to "know" an LED is a white one is to look into it and see the yellowish phospor color. Non white LEDs typically have a clear color to the die as they need no coating to correct the color output.
 

RedForest UK

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It isn't an XR-E, it's an XM-L in the second picture.

I also like the 'industrial' look of the bare ceramic pad, but do think having the reflector come right up to the led dome itself is a better design thermally speaking if it can be done well. It also ensures a perfectly centered emitter.

It also eliminates any possibility of the ceramic pad breaking off of the PCB, which I know isn't normally an issue, but can happen in extreme circumstances (search Surefire Elzetta torture test) or in cases of poor quality soldering to the PCB.

What lights are those in the second picture by the way?
 
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