How much does your HQI bulb cost and how long does it last? I heard they were a 500-1000 hour bulb and cost 200$....any thoughts or do you have a good supplier?
zardoz
first i used a mirror too; the same postion you have it; between the lcd and the lense; but i decided to leave it away because you'll have to much disadvantges compared to a non mirror system:
1st problem i had: a normal mirror reflects the picture 3 times to the screen; that comes from the construction of a mirror; glas silver and final level
the glas reflects and the silver reflects and the final leverl too, so you will have something like shadows on your screen around th emain picture (best visible in dark white to black scenes)
solution: a mirror with no glas before the silver (like ohp have it in a smaller size after the lense)
disadvantage: lightloss because of the special mirror, and even if not, contrast-loss because of the diffusing light between the lcd and the lense (you have the same problem with a normal mirror too);
after i had tried the solution without a mirror i won't go back to the mirror solution and take the disadvantage of more length; as long as the picture is better...
but i like your design very much; it looks really cool and professional; i am looking forward to your final version
best regards slize
first i used a mirror too; the same postion you have it; between the lcd and the lense; but i decided to leave it away because you'll have to much disadvantges compared to a non mirror system:
1st problem i had: a normal mirror reflects the picture 3 times to the screen; that comes from the construction of a mirror; glas silver and final level
the glas reflects and the silver reflects and the final leverl too, so you will have something like shadows on your screen around th emain picture (best visible in dark white to black scenes)
solution: a mirror with no glas before the silver (like ohp have it in a smaller size after the lense)
disadvantage: lightloss because of the special mirror, and even if not, contrast-loss because of the diffusing light between the lcd and the lense (you have the same problem with a normal mirror too);
after i had tried the solution without a mirror i won't go back to the mirror solution and take the disadvantage of more length; as long as the picture is better...
but i like your design very much; it looks really cool and professional; i am looking forward to your final version
best regards slize
eebasist
my bulb cost 75$ regular price(here in Europe it is about 75€) also had a special price of 45$, but on ebay i'll get it for 25$ new shipping and handling included. Til yet i don't have experiences with the bulb life (used for 50 hours since i've finished my projector) but Osram says approx. 2000h with a usage of 3 hours a day...
it is used originally for aquariums so it has to last at least one year... but with that price on ebay i don't care...
my bulb cost 75$ regular price(here in Europe it is about 75€) also had a special price of 45$, but on ebay i'll get it for 25$ new shipping and handling included. Til yet i don't have experiences with the bulb life (used for 50 hours since i've finished my projector) but Osram says approx. 2000h with a usage of 3 hours a day...
it is used originally for aquariums so it has to last at least one year... but with that price on ebay i don't care...
slize
thanks for the pics slize i see how it works now, not bad at all and u are spot on about the mirrors, i lost about 1/3 of light when i used mine but i got not choice as my lcd wont go backwards lol so the mirror it is, yess i could have turned the lcd around the other way but then things start to become big so anyway i ended up with my box of tricks, im thinking in a new design for a screen, maybe sand blasted perspex as it will absorb and reflect the light and light up in the sand blasted area, the sandblastered area would go to the back and the non sandblastered area to the front with some kind of white backing atached to the back that is a flat white, i think it could work like a silver screen maybe even better
Trev
thanks for the pics slize i see how it works now, not bad at all and u are spot on about the mirrors, i lost about 1/3 of light when i used mine but i got not choice as my lcd wont go backwards lol so the mirror it is, yess i could have turned the lcd around the other way but then things start to become big so anyway i ended up with my box of tricks, im thinking in a new design for a screen, maybe sand blasted perspex as it will absorb and reflect the light and light up in the sand blasted area, the sandblastered area would go to the back and the non sandblastered area to the front with some kind of white backing atached to the back that is a flat white, i think it could work like a silver screen maybe even better
Trev
screen idea
also with the screen idea cos when u sandblast it pits, if u get it blastered very finely and with the pits, u will get a flat coloured screen with a nice pro finnished front and with the pits that absorb and reflect light im nearly 100% sure u would get a very wide angle of view
Trev
also with the screen idea cos when u sandblast it pits, if u get it blastered very finely and with the pits, u will get a flat coloured screen with a nice pro finnished front and with the pits that absorb and reflect light im nearly 100% sure u would get a very wide angle of view
Trev
Hi all !
I've read a few things here and I'd like to know if I could find a comparative test of a computer LCD (15') and a Sharp-like LCD :
-Sharp are great because you don't need to dismount them
-but getting a good resolution and contrast is hard and expensive 🙁
-Sharp are smaller so they suit every fresnel ( I ordered a 12*12 one at DIYlab)
What would you advice?
I will have a 12*12' fresnel, a 80mm lens (f=327mm) and a 250W MH.
I've read a few things here and I'd like to know if I could find a comparative test of a computer LCD (15') and a Sharp-like LCD :
-Sharp are great because you don't need to dismount them
-but getting a good resolution and contrast is hard and expensive 🙁
-Sharp are smaller so they suit every fresnel ( I ordered a 12*12 one at DIYlab)
What would you advice?
I will have a 12*12' fresnel, a 80mm lens (f=327mm) and a 250W MH.
Great Design ace3000_1 !!!
So where did you bet a 92 mm projection lens?? Also do you (or anyone else) know if it would be usable with a 10.4" lcd??
So where did you bet a 92 mm projection lens?? Also do you (or anyone else) know if it would be usable with a 10.4" lcd??
bitbyter
howdy bitbyter, gladf u like my design, ill be posting more pics of it tonight maybee as im nearly done with it, the frensel i use is a page magnifyer its a little over 6" in size so it was perfect for my lcd, i have placed it between 2 peices of perspex cos heat will worp the frensel on its own asd it is only thin, ok the lens is just a 90mm magnifying glass modified with handle cut off and filed to shape.
In your design may i sugest a couple of things, firstly u dont need the fan power suply if u use a 110v or mains powered fan, secondly the mirror 1 could melt that fan power supply if it was a cold mirror so i think dont not use a fan power suplly and just use a 80mm or 120mm mains powered fan, ok the next thing i would do is put the balast behind the mirror 2 as it is cooler there and the ballast is not getting heat from the light, and lastly the mirror 1 and light unit i would put on the oposite side of the box in the order u have it so that the light is more of a strait pass through.
one other thing u could do is the gap between the lcd and frensels make a air intake so u get a cool flow of air running through the gaps and going over the light last with the hot air out in the end. Make a air filter to eliminate dust with panty hose
howdy bitbyter, gladf u like my design, ill be posting more pics of it tonight maybee as im nearly done with it, the frensel i use is a page magnifyer its a little over 6" in size so it was perfect for my lcd, i have placed it between 2 peices of perspex cos heat will worp the frensel on its own asd it is only thin, ok the lens is just a 90mm magnifying glass modified with handle cut off and filed to shape.
In your design may i sugest a couple of things, firstly u dont need the fan power suply if u use a 110v or mains powered fan, secondly the mirror 1 could melt that fan power supply if it was a cold mirror so i think dont not use a fan power suplly and just use a 80mm or 120mm mains powered fan, ok the next thing i would do is put the balast behind the mirror 2 as it is cooler there and the ballast is not getting heat from the light, and lastly the mirror 1 and light unit i would put on the oposite side of the box in the order u have it so that the light is more of a strait pass through.
one other thing u could do is the gap between the lcd and frensels make a air intake so u get a cool flow of air running through the gaps and going over the light last with the hot air out in the end. Make a air filter to eliminate dust with panty hose
How's This??
So here is the re-dedigned version. It would most likely be an easier build without the second mirror.
BTW: Does anyone know if you can get front-sruface mirrors from a regular mirror/glass supply place? Also, what types of lenses have people been using as condensors after their light setup. I personally us an aspheric condenser lens but I have seen people use other types. What are the differences/advantages of the different lens types?
So here is the re-dedigned version. It would most likely be an easier build without the second mirror.
BTW: Does anyone know if you can get front-sruface mirrors from a regular mirror/glass supply place? Also, what types of lenses have people been using as condensors after their light setup. I personally us an aspheric condenser lens but I have seen people use other types. What are the differences/advantages of the different lens types?
bitbyter
spot on bitbyter that should work great, where the ballast is i would make a small vent to the left of it in the pic so it can get that cool air from the air gap inbetween the frensels and get sucked out by the exhust fan on the side, as a general rule with fans what goes in must come out the same, so if u go with 2 fans for intake, use 2 fans for extake that way u will have the most efeciency u can get rather than the intake fans fighting the extake to get the air through.
using the one mirror option is the best, u dont want 2 use 2 of them as these things chew light buy the 100"s of lumens lol so i would just go with the one, the light unit u are making is what i was going to draw up for u in the next day as its the same i will do with mine asoon as i get a mh bulb, other than that your projector should work great but u might want to also place some glass inbetween the first frensel and the light to hold back extra heat to the frensel, with a 80mm fan u should have more than enough room to get the air going through the glass, 1st frensel, 2nd frensel and lcd.
Trev
spot on bitbyter that should work great, where the ballast is i would make a small vent to the left of it in the pic so it can get that cool air from the air gap inbetween the frensels and get sucked out by the exhust fan on the side, as a general rule with fans what goes in must come out the same, so if u go with 2 fans for intake, use 2 fans for extake that way u will have the most efeciency u can get rather than the intake fans fighting the extake to get the air through.
using the one mirror option is the best, u dont want 2 use 2 of them as these things chew light buy the 100"s of lumens lol so i would just go with the one, the light unit u are making is what i was going to draw up for u in the next day as its the same i will do with mine asoon as i get a mh bulb, other than that your projector should work great but u might want to also place some glass inbetween the first frensel and the light to hold back extra heat to the frensel, with a 80mm fan u should have more than enough room to get the air going through the glass, 1st frensel, 2nd frensel and lcd.
Trev
Hi.
I'd like to know which panel is darker and needs more Lumens :
a Sharp-like or a 15' TFT from computer (I should get a Samsung 151s)
Really thx for your help 😉
PS : I will use a 250W HQI Osram for a 90 inches diagonal screen.
I'd like to know which panel is darker and needs more Lumens :
a Sharp-like or a 15' TFT from computer (I should get a Samsung 151s)
Really thx for your help 😉
PS : I will use a 250W HQI Osram for a 90 inches diagonal screen.
just a question from an uninformed outsider: what is the reason for using a mirror in the first place? why can't you just beam straight in from behind the lens? is there a space issue with the footprint or something?
sorry if i missed something earlier...i just saw the latest page and didn't bother to read the previous 91. 🙄
/andrew
sorry if i missed something earlier...i just saw the latest page and didn't bother to read the previous 91. 🙄
/andrew
Faustian
There are space issues with footprint, focal length of various lenses, heat dissipation, etc... Including a mirror allows you to "fold" the light into a more compact footprint, and still satisfy focal lengths etc..
There are space issues with footprint, focal length of various lenses, heat dissipation, etc... Including a mirror allows you to "fold" the light into a more compact footprint, and still satisfy focal lengths etc..
Re: Faustian
well...i don't know much about focal length and heat dissipation, but the footprint won't change much if at all, if you simply relocate the projection lens to the right end of the box instead of the bottom. the beam path length stays the same, and you get rid of that mirror in the path. maybe there are other issues involved...?
just trying to help...
/andrew
Property said:
well...i don't know much about focal length and heat dissipation, but the footprint won't change much if at all, if you simply relocate the projection lens to the right end of the box instead of the bottom. the beam path length stays the same, and you get rid of that mirror in the path. maybe there are other issues involved...?
just trying to help...
/andrew
Got it in one. The reason for using a mirror is a) to make the build smaller and to b) make a unit stand vertically. As acc3000_1 states however; every mirror you add cuts down on you brightness. It also makes the build more difficult as aligning the mirror is not the easiest task to accomplish.
For instance say you have a fresnel with a 14" focal length. Well then you want to put your "point light source" at the focal point of your fresnel, so that's 2 feet of distance!
Stick in a mirror and then you can "fold" the light into a 1 foot x 1 foot box instead of having a 2 foot long box...it's just space saving. You'll want to use front-surface mirrors ideally though.
You can also see how you could take this idea and fold the light even further. For instance with 2 mirrors you could make a .66 foot box..etc...But the more mirrors you have, the more light output you'll lose at the mirrors so it's a trade-off.
Stick in a mirror and then you can "fold" the light into a 1 foot x 1 foot box instead of having a 2 foot long box...it's just space saving. You'll want to use front-surface mirrors ideally though.
You can also see how you could take this idea and fold the light even further. For instance with 2 mirrors you could make a .66 foot box..etc...But the more mirrors you have, the more light output you'll lose at the mirrors so it's a trade-off.
Attachments
property: yes, your drawing makes sense. i guess i was misreading bitbyter's diagram as a scale drawing. i hope you can see the difference between the two, and how i came to my conclusion.
in this case, i guess i would have to agree the mirror is a desirable solution.
/andrew
in this case, i guess i would have to agree the mirror is a desirable solution.
/andrew