What percentage of the light is lost in diffusors?

The following LED lights have diffusors which make the lights omnidirectional.
But how much light is lost in the diffusor?

LED panel lightwith diffusor
http://www.ledlightsense.co.uk/products/led-panel-light-300-x-300/

LED light bulb with diffusor..
**broken link removed**

....if a diffusor is used, then does this mean that say a 15W LED lamp only looks as bright as say a 13W LED light without the diffusor?

so would you say a loss of say about 10% in lumens is about right for loss due to the diffusor?

LED lights are still much too expensive to light up a building. LEDs are fine for indicator lights and for traffic and street lights.

The LED lights that I am speaking of would only need manufacturing once.
When the LEDs failed, they would be sent back to a repair centre who just desolder the LEDs that have failed open, and replace them with fresh LEDs.
-or most likely they would manually just desolder all the old leds and hand solder new leds on, then the luminaire would be sent back out into the field.....so even though the led luminaire may be pricey, it only gets made once....and lasts for a 100 years or more....(obviously with leds being periodically replaced, as discussed)
So therefore, done in this manner, would you agree that this re-use brings the LED luminaire price right down?

treez said:

The LED lights that I am speaking of would only need manufacturing once.
When the LEDs failed, they would be sent back to a repair centre who just desolder the LEDs that have failed open, and replace then with fresh LEDs.
-or most likely they would manually just desolder all the old leds and hand solder new leds on, then the luminaire would be sent back out into the field.....so even though the led luminaire may be pricey, it only gets made once....and lasts for a 100 years or more....(obviously with leds being periodically replaced, as discussed)
So therefore, done in this manner, would you agree that this re-use brings the LED luminaire price right down?

Click to expand...

We live in a "throw it away" world. If an electronic product fails then it is replaced, not repaired. Unless the repair person is a little kid who is paid a bowl of rice a day.

Audioguru You're absolutely correct.
Mind you, in UK, for example, we don't have much land-space, and so if we can avoid repeatedly sending glass lightbulbs into land-fill then we're happy............I don't know what happens in Canada, but in UK now, every single piece of trash that goes to the tip is literally hand sorted by scores of workers who filter through it and pick out metal cans etc..
This has been happening since the last three years in UK.
Every single piece of trash is examined and sorted.
So we here in UK don't want to throw away lightbulbs anymore.

Lightbulbs with glass are particularly bad, because it makes it difficult for our scores of rubbish sorters to pick through the rubbish without cutting themselves.

In Canada most of our rubbish cemeteries are full (some are now golf courses). So we truck our rubbish to the United States!
We recycle cars, paper, some plastic things and electronic products but not glass.

I think the difference is that in the UK there is a hefty landfill tax. It is imposed to make it more economical to recycle than dump rubbish and here too the 'cemeteries' are almost at capacity. Poor United States, I would have thought they had enough rubbish of their own without importing more :lol:

( I should add that I have nothing against the USA, I worked in Chicago for a major component and mobile phone manufacturer for quite a long time )

Back to the original question: a good diffuser will only lose a tiny amount of light. Obviously, it disperses it so the illumiation pin each sq cm is less but the total should only be 1- 2% of the light at source. I am excluding losses at particular wavelengths in that estimate, some plastic diffusers will filter out UV light for example.

Brian.