15 March 2007
Colors
So I was thinking about how some of these systems use color wheels, and trying to understand why they aren't using a pure white light... Now, I don't know if this is what they are doing, but something we might consider...
Instead of using white LEDs, what if we use RGB LEDs (like NT-53F0-0428) with a B&W LCD... The LCD would be cheaper, faster transitions, better contrast... Basically, alternate between R/G/B (all LEDs at once) and flood the LCD... which either allows it to pass through or not... In theory, we might be able to get better contrast and faster response times, while still making it cheaper (though a little more complex).
Instead of using white LEDs, what if we use RGB LEDs (like NT-53F0-0428) with a B&W LCD... The LCD would be cheaper, faster transitions, better contrast... Basically, alternate between R/G/B (all LEDs at once) and flood the LCD... which either allows it to pass through or not... In theory, we might be able to get better contrast and faster response times, while still making it cheaper (though a little more complex).
Lumenlab Focal Length Calculator
So I gave this site a quick test...
If we were to use say, this 7.1" LCD...
And say, project a 9' screen...
from132, no 131" away...
We'd need a 8.08" focal length for the lens.
If we were to use say, this 7.1" LCD...
And say, project a 9' screen...
from
We'd need a 8.08" focal length for the lens.
Lights
One of the most obvious issues with projectors (DIY or not) is the lamps/lights. They don't last long and are costly. Obviously we want good quality (and consistent) light (I've read 6500°K), fairly cheap bulbs (ie: $100 or less), long lifetime, ease of obtaining...
I've been thinking about this, and think it might be worth it to try to find an LED alternative.
One company that I found that provides bright LED arrays is Lamina.
An example bulb from them is "NT-52D0-0429 Daylight White" [PDF]. With this one, we can get to 1070 lumens (which doesn't seem like enough) with 6200°K light... Most lamps I found are nowhere in this range of color...
I've been thinking about this, and think it might be worth it to try to find an LED alternative.
One company that I found that provides bright LED arrays is Lamina.
An example bulb from them is "NT-52D0-0429 Daylight White" [PDF]. With this one, we can get to 1070 lumens (which doesn't seem like enough) with 6200°K light... Most lamps I found are nowhere in this range of color...
| Product: | NT-52D0-0429 Daylight White |
|---|---|
| Color Temp. Min. (Kº): | 3950 |
| Color Temp. Max. (Kº): | 6200 |
| Total Incl. Angle: | 140 |
| View Angle[1]: | 61 |
| CRI Min: | 60 |
| CRI Typ: | 68 |
| Test Current (mA): | 1050 |
| Typical (lm): | 878 |
| Min. (lm): | 648 |
| Drive Current (mA): | 1400 |
| Typical (lm): | 1070 |
| Drive Current (mA): | 1050 | |
|---|---|---|
| Distance from Source (Meters) | 1: | 795.6 |
| 2: | 198.9 | |
| 5: | 31.8 | |
| 10: | 8.0 | |
| Drive Current (mA): | 1400 | |
|---|---|---|
| Distance from Source (Meters) | 1: | 969.0 |
| 2: | 242.3 | |
| 5: | 38.8 | |
| 10: | 9.7 | |
| $85.83 | www.arrownac.com |
| $77.12 | www.mouser.com |
| $77.12 | www.digikey.com |
| $122.64 | export.farnell.com |
| direct: | To request a sample or to speak with a sales applications engineer, call us at (609) 265-1401. |
|---|
InventGeek: A Practical Guide to the DIY LCD Projectors
Pretty good rundown showing how to mix-n-match the components to make a DIY system.
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This blog is here to assist with collecting notes and tracking progress on a DIY Front Projection system.
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