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Originally Posted by luke_t Afternoon!
Right, yesterday I took to my setup and lowered my LCD panel to just 5mm from the ohp screen, I funneled the air from the fan through this gap. I thought that the screen might get hotter due to it being closer to the ohp surface... however the reduced space for the air to flow through meant that the air flows through faster and the hottest part of the screen is now only 31 degrees!
I also darkened any areas where like might escape from the edges. After feeling quite please with myself I decided to put the projector to the back of my room.
After refocusing the lense the result was a screen that was massive and sharp! As seen on the picture (again sorry for the poor quality of image) from corner to corner I measured it to be 3m!!!
However at the moment its the creamy colour of my wall that really lets it down. I'll definetly get some Delux brilliance white paint this weekend, hopefully that will improve things!
In case anyone is interested there is a 3M 9550 on ebay in the UK at the moment... http://cgi.ebay.co.uk/ws/eBayISAPI.d...868757875&rd=1
The chap who is selling it goes on to advertise it as a 9700 but from the photos its definetly a 9550.
I'm also hoping that when I get a new bulb it will improve the colour distortion I'm getting, currently very bright at the top, perfect in the middle and very dark at the bottom. |
Excellent news with the cooling, I need to check if I have enough air back pressure to achieve the same. Although....
Having too small a gap means I cant poke a cloth in there to clean the dust.
At some point when the Air system is finished I will be using some ladies tights to filter the air. It may be something you wish to consider too.
I've found there is no problem focussing at any distance, but brightness does suffer a lot as you make it bigger. Its best to check while playing a dark movie to see if you get any loss of detail, rather than using Windows, as Windows is always real bright.
Ultimately, theres no way to decide how bright it is until you have the screen you will be using.
I have found my 4000 Lumen OHP to be sufficient for a 5ft diagonal screen without loss if detail on the darkest of dark movies. It can go much bigger for gaming and in Windows and perhaps to 6ft in dark movies too.
The colour/brightness distortion you have may be partially due to the position of the bulb. The bulb filament/bright spot should be in the centre of the rear reflector. Mine isnt quite, causing the top to be darker than the bottom of the screen. All will be sorted out when the new bulb comes (havent ordered yet).
Since I was last online I've made a prototype shroud for the LCD screen, Here's a couple of photos. It was pretty easy to make, involving measuring basic sizes and then cutting the cardboard to shape. It is taped together with Duct tape which lasts a long time!! My air box for the PC water cooler is about 8 months old now and a prototype that is still running too
It may be preferable to drape black material round then stitch it into shape. Something I will try later.