How bright is 300mcd?

[Acorn Eyes]

Compared to average LEDs found laying around.

[iRileyx]

from a quick google, most "super bright" led's are around 4000. so im guessing 300 would be something like a hdd light on a pc case

[Acorn Eyes]

1 minute ago, RKRiley said:

from a quick google, most "super bright" led's are around 4000. so im guessing 300 would be something like a hdd light on a pc case

that doesnt make sense because some LEDs (that aren't that big) can reach 11000mcd

[iRileyx]

Size doesn't determine how bright a light is.

[Acorn Eyes]

1 minute ago, RKRiley said:

Size doesn't determine how bright a light is.

well its impossible to fit more than 400mcd in less than 2mm

[bob345]

Your average smd led found in led keyboards and pc lights are around 15 lumens and your average 40 watt incandescent light bulb is around 500-600 lumens. I do want to state that perceived "brightness" is not linear as in 600 lumens does not appear twice as bright as 300 lumens. 300 lumens i would say is similar to a small lamp in brightness

[Acorn Eyes]

2 hours ago, bob345 said:

Your average smd led found in led keyboards and pc lights are around 15 lumens and your average 40 watt incandescent light bulb is around 500-600 lumens. I do want to state that perceived "brightness" is not linear as in 600 lumens does not appear twice as bright as 300 lumens. 300 lumens i would say is similar to a small lamp in brightness

Using an online converter, 300mcd at 120° is about 1 lumens. So it's dimmer than a keyboard led.

[mariushm]

Sigh... i've wrote a bunch of long posts trying to explain to you all this ... have a look at my previous messages in that other thread.

 

How bright the led looks to you depends on the view angle of that led. 300 mcd at 120 angle could be less bright than a regular computer case led, 300mcd at 10-15 degrees (narrow angle) would appear to you much brighter.

And I've told you about the specifications listing those values for the maximum continuous current rating the led can handle. In real world, you're probably going to use the led at much lower current, so you have to look in datasheets in graphs at how bright the led would be to a particular current.

Some leds designed for higher current will be more efficient than others at low currents, compared with leds that are from the start designed for low currents... you have to go through lists of leds and settle on a few series of leds and then look at datasheets to figure out which works best for the continuous current you can afford in your project.

 

Also be aware that those tiny leds you're interested in would work at the maximum current in their specs only if kept cool... usually for those tiny tiny leds wide traces to them on pcb is enough, for bigger leds like that Bridgelux that one needs to be on some metal surface (usually with some thermal paste, or some thermal tape)

[Acorn Eyes]

11 hours ago, mariushm said:

Sigh... i've wrote a bunch of long posts trying to explain to you all this ... have a look at my previous messages in that other thread.

 

How bright the led looks to you depends on the view angle of that led. 300 mcd at 120 angle could be less bright than a regular computer case led, 300mcd at 10-15 degrees (narrow angle) would appear to you much brighter.

And I've told you about the specifications listing those values for the maximum continuous current rating the led can handle. In real world, you're probably going to use the led at much lower current, so you have to look in datasheets in graphs at how bright the led would be to a particular current.

Some leds designed for higher current will be more efficient than others at low currents, compared with leds that are from the start designed for low currents... you have to go through lists of leds and settle on a few series of leds and then look at datasheets to figure out which works best for the continuous current you can afford in your project.

 

Also be aware that those tiny leds you're interested in would work at the maximum current in their specs only if kept cool... usually for those tiny tiny leds wide traces to them on pcb is enough, for bigger leds like that Bridgelux that one needs to be on some metal surface (usually with some thermal paste, or some thermal tape)

But if it's a wide angle situated to only shine into a light pipe, there shouldn't be any "lost" light. It all enters the light pipe.

[mariushm]

No, light pipes aren't ideal things that capture all light from a led. From the start, when light travels from led diode to led pipe, you already have about 8% loss. Then the light doesn't go through the pipe all the way to the end 100%, some is lost through the led pipe walls. Especially with wider angle leds, more light is lost. And especially with light pipes that have curves in them, even more light is lost at that curve, not all light gets reflected on the new path.

 

LED Pipes work better with narrow angle leds.  Wide angle leds also often have special plastics on top of the diode that are specially designed to spread light and make it uniform in all directions, which is bad for light pipes where you prefer all light to hit the pipe at a narrow angle so that it gets reflected like lasers hit the walls through fiber optic cables.

 

Do some research if you don't know how things work.

 

Here's something to start you with :

 

Something with more pictures where you can see how light is lost around the light pipes and before the light pipe, if you choose the wrong led or type of light pile :

DESIGNING AND OPTIMIZING LIGHTGUIDES/PIPES – TIPS & TRICKS FOR A STREAMLINED PROCESS

https://www.led-professional.com/resources/downloads-pdf/designing_optimizing_light_guides-pipes_webinar_lambda-research/at_download/file

 

Something with more theory but if you stick with it it's not that difficult. You could skip the heavy stuff there's some parts which are explained in simpler words :

 

Light Guide Techniques Using LED Lamps : 5988-7057EN.pdf

 

[Jonathan W]

I just love how this thread is

"hey guys explain this to me"

[explains thing]

"No way, you're wrong that can't be true"

[Acorn Eyes]

59 minutes ago, mariushm said:

No, light pipes aren't ideal things that capture all light from a led. From the start, when light travels from led diode to led pipe, you already have about 8% loss. Then the light doesn't go through the pipe all the way to the end 100%, some is lost through the led pipe walls. Especially with wider angle leds, more light is lost. And especially with light pipes that have curves in them, even more light is lost at that curve, not all light gets reflected on the new path.

 

LED Pipes work better with narrow angle leds.  Wide angle leds also often have special plastics on top of the diode that are specially designed to spread light and make it uniform in all directions, which is bad for light pipes where you prefer all light to hit the pipe at a narrow angle so that it gets reflected like lasers hit the walls through fiber optic cables.

 

Do some research if you don't know how things work.

 

Here's something to start you with :

 

Something with more pictures where you can see how light is lost around the light pipes and before the light pipe, if you choose the wrong led or type of light pile :

DESIGNING AND OPTIMIZING LIGHTGUIDES/PIPES – TIPS & TRICKS FOR A STREAMLINED PROCESS

https://www.led-professional.com/resources/downloads-pdf/designing_optimizing_light_guides-pipes_webinar_lambda-research/at_download/file

 

Something with more theory but if you stick with it it's not that difficult. You could skip the heavy stuff there's some parts which are explained in simpler words :

 

Light Guide Techniques Using LED Lamps : 5988-7057EN.pdf

 

Wait so what's the point of wide angle leds on such a small scale? 

 

Anyways would I be better off using a light pipe with a couple leds (small viewing angle of course) or a circlet of LEDs? 

 

I would love to make it into sort of a utility ring, but I think ultimately I'll stick with LEDs being a cosmetic element.

[mariushm]

You wouldn't put narrow angle leds on a computer case, or as a stand by/ power on led on a monitor for example, because it would basically burn someone's eyes or annoy him and especially during the night it would piss people off. You use diffuse and often wide angle leds for that.

Wide angle diffuse leds are also often used behind opaque plastics letting some light go through the plastics with nice gradient fade out effect towards the edges.. looks pretty.

 

In some cases wide angle leds are also used for signage, think dot matrix text displays, scrolling text in buses, trains etc in places where you don't care about powerful sun rays hitting the display.. you just put a slightly opaque material over the leds and it saves money with lens and other crap.

 

As for your other questions, you should make up your mind on what exactly you want. All i know is you want a ring, but it seems you change your mind about everything else about it. It's a flashlight, now it's utility ring, leds were important now they're cosmetic element ... figure things out, it's pointless to waste my time until time. 

Decide on size of ring , decide on how big can it be on top because that also may decide what batteries to use, decide on batteries because that give you the voltage and maximum current you have, then based on that decide on led or leds.

You barely have power for one led if you want the power source to be in the ring, and you're thinking of several leds.

 

[Acorn Eyes]

7 minutes ago, mariushm said:

You wouldn't put narrow angle leds on a computer case, or as a stand by/ power on led on a monitor for example, because it would basically burn someone's eyes or annoy him and especially during the night it would piss people off. You use diffuse and often wide angle leds for that.

Wide angle diffuse leds are also often used behind opaque plastics letting some light go through the plastics with nice gradient fade out effect towards the edges.. looks pretty.

 

In some cases wide angle leds are also used for signage, think dot matrix text displays, scrolling text in buses, trains etc in places where you don't care about powerful sun rays hitting the display.. you just put a slightly opaque material over the leds and it saves money with lens and other crap.

 

As for your other questions, you should make up your mind on what exactly you want. All i know is you want a ring, but it seems you change your mind about everything else about it. It's a flashlight, now it's utility ring, leds were important now they're cosmetic element ... figure things out, it's pointless to waste my time until time. 

Decide on size of ring , decide on how big can it be on top because that also may decide what batteries to use, decide on batteries because that give you the voltage and maximum current you have, then based on that decide on led or leds.

You barely have power for one led if you want the power source to be in the ring, and you're thinking of several leds.

 

I meant specifically smaller scale LEDs like the ones I'm looking at. The only application I can think of is that gradient behind plastics. 

 

And you don't need to help if you don't want to, don't have the time to, or just don't want to bother answering dumb questions. In fact I feel really guilty everytime you respond with a long, well-thoughtout response to a project I'm seemingly changing every second. I seriously appreciate your help, it's helping me learn more about the electric trade and I'm indebted to you. But I don't want you to feel like it's a chore helping me.

 

As for the project itself, I've settled on the fact that batteries the size I'm thinking of are unrealistic and instead I'm going with a lithium ion bracelet to power them. 

 

By utility I meant flashlight, since there's not a lot of utility options using LEDs I can think of, but if it's too impractical I'm willing to go with a cosmetic look to it (light pipe).  

 

I've already sized the ring and I'm preparing the mold for it. So I'm approximately 5mm in width 3mm width in the cavity. So I now know my constraints. 

 

Again I'm really grateful you've answered my questions, but I don't want you to answer them unwillingly. I know I can be slow at times, and I don't want you to wait.

[mariushm]

Here's another application for wide angle leds in tiny packages:

 

 

The straps have a bunch of small leds and a microcontroller with radio receiver and a small memory chip and lithium batterries hidden in that plastic box under the pcb. 

They're programmed with several patterns before being given to concert people and then the microcontroller just listens on the radio waves for signal which tells it to switch leds to specific patterns stored beforehand in its memory.

The battery (well batteries, because there's 2 strong ones used for leds and one for the micro and radio) last up to maybe about 2-6 hours of blinking depending on patterns and basically they're thrown away after the concert.

Since it's usually night when concerts happen the leds don't have to be super bright or behave as flashlights, they just have to pass through the band material or the thin plastic.

 

 

The individual leds are kinda big (5050 packages) but they could have easily gone for small separate tiny leds.. it was just easier to solder the bigger packages on the flexible strip in this particular case.

 

[Acorn Eyes]

31 minutes ago, mariushm said:

Here's another application for wide angle leds in tiny packages:

 

 

The straps have a bunch of small leds and a microcontroller with radio receiver and a small memory chip and lithium batterries hidden in that plastic box under the pcb. 

They're programmed with several patterns before being given to concert people and then the microcontroller just listens on the radio waves for signal which tells it to switch leds to specific patterns stored beforehand in its memory.

The battery (well batteries, because there's 2 strong ones used for leds and one for the micro and radio) last up to maybe about 2-6 hours of blinking depending on patterns and basically they're thrown away after the concert.

Since it's usually night when concerts happen the leds don't have to be super bright or behave as flashlights, they just have to pass through the band material or the thin plastic.

 

 

The individual leds are kinda big (5050 packages) but they could have easily gone for small separate tiny leds.. it was just easier to solder the bigger packages on the flexible strip in this particular case.

 

Oh interesting, I still think the market for wide angle small LEDs isn't huge. But who am I to judge.