The brightness is the worst spec on our projectors. that is in my opinion our next step; how could we improve the lumens on the projected image?
some are going for smaller arc bulbs, more controlability on the light so it means more lght output. SOme are going for more powerfull lamps (1000W, 1500W...) much light on the source with same looses means more light on putput as well.
What i have been looking for is a higher efficiency reflector. The ikeas sphereical reflector+400W lamp would give you somewhere 20% light from the bulb directed to the lcd. This means somewhere 6500 lumens.
What i was thinking was going for a 150W lamp (13000 lumens) and an eliptical reflector. The eliptical would take much more light from the lamp (77%) and direct it to the lcd. So the initial 13000 from the lamp would get to 10000 lumens directed to the lcd, it is even more than the 400W lamp!! (all theorical assumtions based).
so I decided to investigate that way;
first test seem to be very promising. Will let you know when luxmeter readings are done.
some are going for smaller arc bulbs, more controlability on the light so it means more lght output. SOme are going for more powerfull lamps (1000W, 1500W...) much light on the source with same looses means more light on putput as well.
What i have been looking for is a higher efficiency reflector. The ikeas sphereical reflector+400W lamp would give you somewhere 20% light from the bulb directed to the lcd. This means somewhere 6500 lumens.
What i was thinking was going for a 150W lamp (13000 lumens) and an eliptical reflector. The eliptical would take much more light from the lamp (77%) and direct it to the lcd. So the initial 13000 from the lamp would get to 10000 lumens directed to the lcd, it is even more than the 400W lamp!! (all theorical assumtions based).
so I decided to investigate that way;
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
first test seem to be very promising. Will let you know when luxmeter readings are done.
well, finally you did it. I'll follow that one with a big attention.
Are you doing these test with a 15" lcd screen or a smaller one??
I assume that the size of you elliptical reflector is calculated for your lcd or did you manage to organize this with a condensor lens?
How can you let us hanging with any lux values
you dark diyist 😉
Are you doing these test with a 15" lcd screen or a smaller one??
I assume that the size of you elliptical reflector is calculated for your lcd or did you manage to organize this with a condensor lens?
How can you let us hanging with any lux values
you dark diyist 😉
yes, you hit the nail with your lcd size question. I plan on going for the hami 8".
but as you sugested, the condensor lens at 2nd focal point of the elipticla reflector can adjust the light cone to the desired one (but take care because we need to check both things; 1)light cone or ight aperture, and 2)distance from the light point to the rear fresnell.
shining a 220 mm focal rear fresnell from 300mm mm distance with the propper light cone (no more than needed... no less than needed) will not be paralell outputed...
SO a condenser lens + rear fresnell focal lengh must be considered to see what elptical for what lcd size do we need.
but as you sugested, the condensor lens at 2nd focal point of the elipticla reflector can adjust the light cone to the desired one (but take care because we need to check both things; 1)light cone or ight aperture, and 2)distance from the light point to the rear fresnell.
shining a 220 mm focal rear fresnell from 300mm mm distance with the propper light cone (no more than needed... no less than needed) will not be paralell outputed...
SO a condenser lens + rear fresnell focal lengh must be considered to see what elptical for what lcd size do we need.
the relfector is from china suplier, the problem with them is always the same, the minimun quantity... shipping charges... I needed to buy 10 of them.
The lamp is locally, it is quite expensive (somewhere 55€) but i got them for 45€ because i know the seller since i started to ask him about all kind of lamps when i found this website ;D.
will post lux readings soon.
The lamp is locally, it is quite expensive (somewhere 55€) but i got them for 45€ because i know the seller since i started to ask him about all kind of lamps when i found this website ;D.
will post lux readings soon.
Is that a real elliptical reflector or a cone-axis elliptical one? I'v got a cone-axis one from a group-buy last spring.
it is the same specs as the one here http://www.edmundoptics.com/onlinecatalog/displayproduct.cfm?productID=1412
what about your eliptical? did it work nice?
what about your eliptical? did it work nice?
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
this is a very small incandescent lamp (2W). So i can look at it and do not get blind on the try.
The F2 circle is dependent of two things; the distance form the reflector to the projecting plane and the depth of the lamp inside the reflector. The smallest circle i can get is somewhere 1cm diameter, buti beliebe it to get worse when i use the 9mm arc CDM-T lamp.
Rox ,
depending on the position of the lamp, you have between 30-60% (rough estimate) of the light which do not hit the reflector and then do not go to the second focal point.
a small spherical mirror in front of the bulb (smaller than the reflector and placed into the reflector) would force all ray to hit the reflector and to be focused at the F2. This might be necessary if you want to aqual a 400W output efficiency particularly wxith the cdm-t lamp.
depending on the position of the lamp, you have between 30-60% (rough estimate) of the light which do not hit the reflector and then do not go to the second focal point.
a small spherical mirror in front of the bulb (smaller than the reflector and placed into the reflector) would force all ray to hit the reflector and to be focused at the F2. This might be necessary if you want to aqual a 400W output efficiency particularly wxith the cdm-t lamp.
you have to consider the lamp arc light distribution, the front side (light going out of the reflector) is not very efficient. It is generally acepted that there is 1 stereoradian shadow because of the G12 base and other 1 stereoradian shadow because of the phisical construction on this lamps top side. Will post a graphic if i can find it again. Hold on
An externally hosted image should be here but it was not working when we last tested it.
just a note;
this is an osram HQI 150W G12 as well, but the burning cell is not axiall as my philips CDM-T. It is one of the rasons why I choosed the philips.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
this is an osram HQI 150W G12 as well, but the burning cell is not axiall as my philips CDM-T. It is one of the rasons why I choosed the philips.
An externally hosted image should be here but it was not working when we last tested it.
My mozilla did not like those last two links, They worked better in IE though.
Well, it works quite allright, but I have the distances a bit off so I get a hot spot. I will change it soon when I get my new ballast and igniter for my CDM-T. I will actually rebuild the whole projector.
That incandescent test was very nice, I will try it when I get hold of one.
Well, it works quite allright, but I have the distances a bit off so I get a hot spot. I will change it soon when I get my new ballast and igniter for my CDM-T. I will actually rebuild the whole projector.
That incandescent test was very nice, I will try it when I get hold of one.
you can test it with a typical cheap led (3mm red/green ones). It is incredible how efficient this reflector is.
I've got the same phillips lamp. Its very true that a small spherical on the tip would get a lot more light to the reflector but the lamp has this annoying pinch point on the end. The envelope is also too long to get that reflector to the right distance. The paper in the box also says dont have any conductor within 30mm i seem to remember. I think the startup voltage would cause premature wear from ionization in the direction of that conductor. Guy's large spherical idea is doable - but well, large.
I'm curious about the logevity of these reflectors. Is is a cold reflector like the edmunds? Most sites say the cold reflectors have limited life. Im wondering about replacement cost per 3-5,000 hrs. The chinese one might still be a deal? How much was it?
Ive been away for a few months while i waited for the HDTV & HDMI parts to start being produced. I still cant find a HDMI video card to pair with the HDMI LCDs. 🙁
The nice thing about this lamp is the limited heat which means the solution can have a quiet fan. My 4" radio shack fan is silent on good bearings. This makes a much better movie zone.
I'm curious about the logevity of these reflectors. Is is a cold reflector like the edmunds? Most sites say the cold reflectors have limited life. Im wondering about replacement cost per 3-5,000 hrs. The chinese one might still be a deal? How much was it?
Ive been away for a few months while i waited for the HDTV & HDMI parts to start being produced. I still cant find a HDMI video card to pair with the HDMI LCDs. 🙁
The nice thing about this lamp is the limited heat which means the solution can have a quiet fan. My 4" radio shack fan is silent on good bearings. This makes a much better movie zone.
can you believe my light store shop doesn´t give me the G12 base for my lamp yet? dam, I should have ordered in 5 diferent shops and take the first one coming 😀.
I have to wait for that base. Will post if any news.
I have to wait for that base. Will post if any news.
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