hey stelleg151
you're using around 1000 leds ?...made me think, if you have a look at the picture in my previous post of the luxeonIII, it has flat terminal plates, i had been worrying about my cackhanded soldering skills - was i going to cook the leds before i'd even used them ?...and then i wondered if there was another way to connect them
when i was a kid i had this reusable paper staple/paperclip doodad, which had a kind of special tool to open and place a sprung metal clamp (basically just a piece of pressed steel) around sheets of paper,
i was concerned about 32 solders, but 1002 or more ! ?
is there a miniature clamp like what i had as a kid, that'd do the electrical connections ?
we will both have potential need to replace individual leds, and although a thousand or so clamps might seem a lot of work, it could be the way to go , if such a thing exists
of course you may be perfectly happy to do all that soldering, but could you alternatively use insulated mini screw terminals ?
you're using around 1000 leds ?...made me think, if you have a look at the picture in my previous post of the luxeonIII, it has flat terminal plates, i had been worrying about my cackhanded soldering skills - was i going to cook the leds before i'd even used them ?...and then i wondered if there was another way to connect them
when i was a kid i had this reusable paper staple/paperclip doodad, which had a kind of special tool to open and place a sprung metal clamp (basically just a piece of pressed steel) around sheets of paper,
i was concerned about 32 solders, but 1002 or more ! ?
is there a miniature clamp like what i had as a kid, that'd do the electrical connections ?
we will both have potential need to replace individual leds, and although a thousand or so clamps might seem a lot of work, it could be the way to go , if such a thing exists
of course you may be perfectly happy to do all that soldering, but could you alternatively use insulated mini screw terminals ?
Brightside makes an LCD that is backlit by a large array of LEDs (30x40 or something like that). Their gimmick is to adjust the brightness of individual LEDS to deliver light only where it's needed and save power while improving contrast. Yet the backlight assembly is water-cooled, requiring dual radiators for a 37" display. And this is a display you are supposed to look at directly, NOT a 110" projection screen.
This is because LEDs are inefficient compared to anything except normal tungsten incandescents in terms of power versus light output, and struggle to beat fluorescents in cost-effectiveness due to long life (they are still less efficient than fluorescents in terms of power versus light). They have other advantages in terms of weight and compactness, and ease of use. But if you want a LOT of light and in a manageable beam, LEDs just aren't the ticket yet.
This is because LEDs are inefficient compared to anything except normal tungsten incandescents in terms of power versus light output, and struggle to beat fluorescents in cost-effectiveness due to long life (they are still less efficient than fluorescents in terms of power versus light). They have other advantages in terms of weight and compactness, and ease of use. But if you want a LOT of light and in a manageable beam, LEDs just aren't the ticket yet.
right now, my room is being lit by a 1.5 watt led lightbulb, which i can tell you is at least 55% as bright as my other 4 watt flourescent lightbulb
led bulb is one and a half times brighter than florescent
led bulb is one and a half times brighter than florescent
@Meidoracing: Yes you should only need one fresnel.
@CBM5: Im not sure how you can possibly back up the statement that LED's are inefficient..... They are generally weak for lighting rooms and large areas because they are directional lighting. AKA they shoot light in a 12-25 degree angle. If by efficiency you mean non-directional lighting in a space restricted environment then you are correct. To replicate the light of a MH bulb in a room would take an absurd amount of LED's, thousands of them put in a 3d dome-style array. However, if you managed to pull if off, Im betting you could outdo say a 400watt MH bulb, it would just be extremely inconvenient and large. Basically, I think that it will be a while before say a spotlight for a large theatre is powered by LED's, but I think a 60" projection screen is definately coming in the near future. I believe large companys are already planning to come out with LED lit RPTVs going up to 50".
@throwit: Yes I am using that many. I was scared too, but I am no longer, as we have a pioneer from an unusual area of interest. Aqua lighting. This guy has made quite an impressive array of LED's for lighting his tank, and he claimed that 400 only took him 8 hours. I am perfectly willing to spend 8 hours soldering for this project. He even done some testing for us.
For all of those LED doubters: LED Array for aquarium, + lux measurements
As you can see in the second chart, his array of LED's is right on the heels of a 250watth MH at 12" away, which is around the distance to a common rear fresnsel. This is the most promising data I have seen for an array light source yet.
I am not claiming that it will definatley happen, but I am as hopeful as ever, having just found this guy yesterday.
EDIT: Found the LED RPTV: LED RPTV
@CBM5: Im not sure how you can possibly back up the statement that LED's are inefficient..... They are generally weak for lighting rooms and large areas because they are directional lighting. AKA they shoot light in a 12-25 degree angle. If by efficiency you mean non-directional lighting in a space restricted environment then you are correct. To replicate the light of a MH bulb in a room would take an absurd amount of LED's, thousands of them put in a 3d dome-style array. However, if you managed to pull if off, Im betting you could outdo say a 400watt MH bulb, it would just be extremely inconvenient and large. Basically, I think that it will be a while before say a spotlight for a large theatre is powered by LED's, but I think a 60" projection screen is definately coming in the near future. I believe large companys are already planning to come out with LED lit RPTVs going up to 50".
@throwit: Yes I am using that many. I was scared too, but I am no longer, as we have a pioneer from an unusual area of interest. Aqua lighting. This guy has made quite an impressive array of LED's for lighting his tank, and he claimed that 400 only took him 8 hours. I am perfectly willing to spend 8 hours soldering for this project. He even done some testing for us.
For all of those LED doubters: LED Array for aquarium, + lux measurements
As you can see in the second chart, his array of LED's is right on the heels of a 250watth MH at 12" away, which is around the distance to a common rear fresnsel. This is the most promising data I have seen for an array light source yet.
I am not claiming that it will definatley happen, but I am as hopeful as ever, having just found this guy yesterday.
EDIT: Found the LED RPTV: LED RPTV
Hey superdave, its awesome that were both still at it 🙂 (of course one has a working projector and the other doesnt, but thats ok.
)
The reason I have been staying away from the bright luxeons is because they (from what I have seen) 1. Usually need heatsinks. 2. Are relatively expensive. Both of these observations made me think they wont be great for an array.
I linked the ebay seller I was planning on buying from, and plan to undercurrent them a bit, as I doubt they are the highest quality. The prospect of dimming is very cool, another fun reason to try LEDs.
Here is my intial plan. I plan on first buying a bunch and just messing around with them, to learn how they perform, how the current changes as they heat up, etc. Then I will buy the necessary materials and hopefully build an array like the following : My Current Plans
Biggest downside? I have to wait until I get home to the US to start playing. (in Singapore now, traveling around asia this summer).
Edit: Oh yeah, Ive been frequenting that site for the calculators etc. Linear1 is awesome.
)The reason I have been staying away from the bright luxeons is because they (from what I have seen) 1. Usually need heatsinks. 2. Are relatively expensive. Both of these observations made me think they wont be great for an array.
I linked the ebay seller I was planning on buying from, and plan to undercurrent them a bit, as I doubt they are the highest quality. The prospect of dimming is very cool, another fun reason to try LEDs.
Here is my intial plan. I plan on first buying a bunch and just messing around with them, to learn how they perform, how the current changes as they heat up, etc. Then I will buy the necessary materials and hopefully build an array like the following : My Current Plans
Biggest downside? I have to wait until I get home to the US to start playing. (in Singapore now, traveling around asia this summer).
Edit: Oh yeah, Ive been frequenting that site for the calculators etc. Linear1 is awesome.
Very cool! I haven't personally used the Luxeons, but you get more bang for your buck I think. If you get 1000 LEDs for $200 (20 cents a piece) and they put out 3 lumens a piece, that's about $0.07 / lumen. The Luxeon puts out 113 lumens and costs $5.50. That's about $0.05 / lumen. Also, you don't have 1000 LEDs to wire up. 🙂 But, cooling could be an issue, although I think if thought out properly and taken into consideration right at the start, it wouldn't be a problem. I am still interested in hearing about your results even if I have to wait until August! Sorry to hear about your other projector not doing so well. Best of luck!
Yeah, Miedoracing, the reason you need a point source is so you can use a back fresnel. The reason for the back fresnel is to get an even amount of light (from the point source) spread onto the LCD. Using a point source light (MH Bulb) without a back fresnel, you get a bright spot in the middle of the screen and horrible lighting drop off.
Ok, so if the light is spread (in this case physically not optically) around the LCD, you don't need a back fresnel to "even" out the light. It's already even. You still need a field fresnel to capture that large area of light and bring it back down to a point (the projection lens).
That is a good question though.
Yeah, Miedoracing, the reason you need a point source is so you can use a back fresnel. The reason for the back fresnel is to get an even amount of light (from the point source) spread onto the LCD. Using a point source light (MH Bulb) without a back fresnel, you get a bright spot in the middle of the screen and horrible lighting drop off.
Ok, so if the light is spread (in this case physically not optically) around the LCD, you don't need a back fresnel to "even" out the light. It's already even. You still need a field fresnel to capture that large area of light and bring it back down to a point (the projection lens).
That is a good question though.
here's a doodle of what an led lamp for an existing front projector might look like... http://www.avforums.com/forums/attachment.php?attachmentid=27547&d=1143516571
superdaveumo said:
Good point about cost per watt, but the reason that I went with these is because of their small angle of light. I want the most light (lux) on the LCD coming through relatively perpindicular. The luxeons have an angle of 140 degrees or more. That means they are emitting 20000 mcd. Now, say only about 10 degrees (guesstimation here, but I think its a reasonable number) of that light will go through the panel at an angle small enough to get directed by the fresnel into the projection lens (Assuming you dont have some sort of elliptical reflector behind each luxeon), you will only be getting 20000mcd per luxeon for those 10 degree sections, whereas the cheaper 12 degree will be getting 100000 mcd for each of their 10 degree sections.
I admit I dont fully understand how MCD and Lux ratings work, but In my head it works 😀.
I agree the 140 degree angle would be a problem. But... if you have a luxeon with a 30 degree angle with 113 lumens.. That would be excellent. In fact, if you get the "spot" lens for the LED then it does narrow the light into around a 10 degree beam.
We need the best of both worlds. Small angle and bright light. Seems LED makes don't do both right now.
We need the best of both worlds. Small angle and bright light. Seems LED makes don't do both right now.
superdave, you get a led and a meter ordered yet. i am actually really interested in the readings.
whatever happened to flateric ?...what he did was so cool, i wonder if he went into setting up production or something - still you'd have thought we would have heard from him ?
although it doesn't say much there's this pdf about pulse width modulation
although it doesn't say much there's this pdf about pulse width modulation
i took the first tentative steps toward taking my lp240 apart...(you can read more at av forums uk )
Attachments
If somebody could find out how I could replace my 150 watt UHP bulb in my Hitachi PJ TX200 lcd projector with a much more efficient bulb, that would be awesome. LED or otherwise. Probably not possible at the moment. There is the issue of colour temperature too. You would want the replacement bulb to at least be similar in K to the stock bulb.
Here's hoping LED lighting makes more progress! Efficient lighting is the way to go 🙂
Here's hoping LED lighting makes more progress! Efficient lighting is the way to go 🙂
Miedsoracing,
I haven't yet. A friend from back east moved out here the other day and I've been helping with getting her moved into her new place.
BUT! Luxeons are around $6 and I've been reading on ebay about lux meter being around $30. So there's no reason why I shouldn't order these tonight or very soon!
I haven't yet. A friend from back east moved out here the other day and I've been helping with getting her moved into her new place.
BUT! Luxeons are around $6 and I've been reading on ebay about lux meter being around $30. So there's no reason why I shouldn't order these tonight or very soon!
throwit,
Those two things you point to in your photo of the lamp assembly look like plastic lens which help focus/disperse the light so that it is as even as possible. I am just guessing, but I think that is probably what they are for and I would not imagine that you can do without them entirely, or at least, not without something that performs that function in some fashion. Also, in all likelyhood, the dispersion pattern of whatever LED lamp setup you come up with may be different than the dispersion pattern of the bulb that the projector is designed to use right now.
Anyhow...good luck in your project 🙂
This just reminds me that I could have kept one of my older Panasonic PT-AE100's to experiment in this exact way. Oh well, I will watch what others are doing for now, and research the LED lamp world for now.
Those two things you point to in your photo of the lamp assembly look like plastic lens which help focus/disperse the light so that it is as even as possible. I am just guessing, but I think that is probably what they are for and I would not imagine that you can do without them entirely, or at least, not without something that performs that function in some fashion. Also, in all likelyhood, the dispersion pattern of whatever LED lamp setup you come up with may be different than the dispersion pattern of the bulb that the projector is designed to use right now.
Anyhow...good luck in your project 🙂
This just reminds me that I could have kept one of my older Panasonic PT-AE100's to experiment in this exact way. Oh well, I will watch what others are doing for now, and research the LED lamp world for now.
Sounds good Superdave, just check 1, then maybe 4 LEDs and tape off a 1 cm square, on the opposite side of the lcd. That should tell a good test of how much light will get through. I will keep my fingers crossed for ya, but still think you will have a lux rating of 10-15 on the opposite side. I have an average of 7-8,000 lux on the far side at 9 different spots for example.
@throwit: Looks great man! Good luck, Im excited to see how it turns out. I have to admit I wasnt enthusastic about your project because I thought it would be too small of an area to get enough light from LEDs, but looks like you may have found a workable solution. You probably already know this, but you should check the voltage of your projectors powersupply that is powering the lamp, so you know what size resistor to use. To get a quick and easy diagram of how to set up your wiring and resistors, use this link: Linear1 Diagram Calculator
@meidosoracing: Yeah I hoppe we can manage more than that 🙂. Im a little unsure of where you are measuring your lux. Im guessing you mean on the other side of the LCD, but not sure, if you could clarify a bit that would be great, thanks.
@meidosoracing: Yeah I hoppe we can manage more than that 🙂. Im a little unsure of where you are measuring your lux. Im guessing you mean on the other side of the LCD, but not sure, if you could clarify a bit that would be great, thanks.
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