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Fuzzy blue or violet laser dot?

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thundershock47

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I'm not an expert on laser pointers, and i just got a blue or violet laser pointer. Not sure which, because my brother ordered it from amazon.com, the title says violet, but i dont know if thats considered the same thing as blue or blu-ray in laser pointers. So one thing i noticed is when i point it at the wall the dot seems very large out of focus, and fuzzy. I heard somewhere that blue lasers appear this way because our eyes cannot really comprehend the color or wavelength or somthing. I also heard that once you use the laser for a while and your eyes will adjust and it wont be fuzzy anymore. Is that true? And would my eyes make the dot appear more big? On my green and red the dots are small, but it has light shining around the dot. The blue or violet one just seems to have one big dot with little light. Fill me in?
 





Sigurthr

Sigurthr

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405nm doesn't focus properly because it is far out of the center of our visual spectrum. As a result, it appears "fuzzy". Also, the beam diameters of 405nm diodes are larger than the average cheap red, and way larger than the standard dpss green. So, between the increased beam diameter and the trouble our eyes have focusing 405nm, it is normal.

Not everyone perceives 405nm the same, and not everyone can see it equally well. So, I can't really answer the rest because it depends on the individual.
 
Fretwrecker94

Fretwrecker94

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Unfortunately for me, and everyone I assume as I have not heard of any cases, my eyes haven't "adjusted" to 405nm. I've used my 405nm lasers a lot and I can tell you it always has looked the same. I pick 405nm decently I think, so I'm not complaining. By the way I got a blu-ray off of Amazon recently. They're pretty overspec. Mine can light matches when focused using an external lens. So yours might be able to do so as well! Just be safe!
 
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thundershock47

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are there any household items that could be used as a lens or somthing to help a laser burn, somthing that would be found in most households?
 
Fretwrecker94

Fretwrecker94

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If you don't have a magnifying glass, any aspherical glass piece will work. Basically they're lenses that look like half spheres. Let us know how it turns out!
 
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thundershock47

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I read somewhere that magnifying glasses don't help laser pointers burn. Here is what the person said on the website Yahoo answers.

what the person asked: How intense could a laser pointer be with a magnifying glass?
Similar to burning leaves using the sun

answer:
Less intense than without the magnifying glass.

You can burn things with the sun and a magnifying glass because you are focusing the sun's output to a very small area. A laser is point focused. You can't increase the power with optics. Any extra mediums the laser would pass through would actually reduce the final power.

So is that incrorect? or can magnifying glasses actually help you burn things with a laser pointer?
 
Lotus_Darkrose

Lotus_Darkrose

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thundershock47 said:
I read somewhere that magnifying glasses don't help laser pointers burn. Here is what the person said on the website Yahoo answers.

what the person asked: How intense could a laser pointer be with a magnifying glass?
Similar to burning leaves using the sun

answer:
Less intense than without the magnifying glass.

You can burn things with the sun and a magnifying glass because you are focusing the sun's output to a very small area. A laser is point focused. You can't increase the power with optics. Any extra mediums the laser would pass through would actually reduce the final power.

So is that incrorect? or can magnifying glasses actually help you burn things with a laser pointer?
Click to expand...

Um...correct optics will bring a straight beam to a focal point, which helps burning. Regardless of any power loss it still focuses the laser to a point.
 
Fretwrecker94

Fretwrecker94

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thundershock47 said:
I read somewhere that magnifying glasses don't help laser pointers burn. Here is what the person said on the website Yahoo answers.

what the person asked: How intense could a laser pointer be with a magnifying glass?
Similar to burning leaves using the sun

answer:
Less intense than without the magnifying glass.

You can burn things with the sun and a magnifying glass because you are focusing the sun's output to a very small area. A laser is point focused. You can't increase the power with optics. Any extra mediums the laser would pass through would actually reduce the final power.

So is that incrorect? or can magnifying glasses actually help you burn things with a laser pointer?
Click to expand...

Very incorrect. If focusing did not matter, we could burn large areas with an unfocused beam. Like Lotus_Darkrose said, it concentrates the energy into a focal point. It's like when you lay on a bed of nails. 150 pounds across 1000 nails is no where near as bad as 150 pounds across 1 nail.

I'd suggest you search for answers to laser related questions here, on a dedicated enthusiast site, as opposed to Yahoo Answers.
 
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thundershock47

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Yeah yahoo answers really isn't very reliable.

Anyway, i tried it, no luck. No burning. Its not really that surprising though, because it is supposed to be 5mw. know it is more than that though. If i point it at some thin black paper without the magnifying glass, for about 20 seconds and put my cheek up to it, i can feel it is warm. I used the glass and i didn't really feel much of a difference. I guess mine just isnt powerful enough.
 
Fretwrecker94

Fretwrecker94

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thundershock47 said:
Yeah yahoo answers really isn't very reliable.

Anyway, i tried it, no luck. No burning. Its not really that surprising though, because it is supposed to be 5mw. know it is more than that though. If i point it at some thin black paper without the magnifying glass, for about 20 seconds and put my cheek up to it, i can feel it is warm. I used the glass and i didn't really feel much of a difference. I guess mine just isnt powerful enough.
Click to expand...

All NewWish style pen lasers of all colors are. If it really were 5mW of 405nm, you'd barely see it.

The "<5mW" is more of a "no promises, but its over 5mW" kind of thing. Also its for FDA Regulation.
 
qumefox

qumefox

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Acually <5mW means it's less than 5mW (well, it's supposed to be anyway) That's what the < is.

However the newwish 405nm pens generally run between 40 and 60mW Though i've seen one as high as 85mW before.
 
xoul

xoul

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A picture would help identify your problem, but it sounds like you just have something on the lens to me.
 
geekypyro21

geekypyro21

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Ya its either how you are focusing the laser or what you are trying to burn. I would recommend focusing it to the smallest point possible on some black leather and see if the leather starts to smoke.
 
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