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Jonpro03
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Hello,
My name is Jon Proietti and I am an intern at a digital signage company. We've been looking into the possibility of using full color LCD displays outdoors. We want to increase the light output through the LCD so that it will be more easily visible in direct sunlight.
We purchased a large LCD television to play around with. Here is my understanding of how it's set up; please correct me if I am wrong.
At the very back is a series of white LEDs for the back light. 2" in front of them is a diffuser followed by two sheets of what I would call prism sheets. Their function seems to be directing the diffused light directly forward. There is a half inch of space before the LCD module, which I assume has the polarizer(s?) built in.
The original backlight put out roughly 6000 nits (cd/m2) and an all white message on the display allowed 280 nits through. Roughly 5%.
We built a jig and replaced the backlight with our own design, capable of 16000 nits. But somewhere in the process I lost a lot of throughput.
I'm not sure where I went wrong. Maybe it's that the jig is not enclosed and light is escaping. I know that some light is bouncing off of the diffuser. Maybe I need to enclose the jig with some reflective white surface to reflect the light back?
I've also considered that maybe I couldn't get an accurate reading of the original backlight LEDs. They are spaced about 3" apart, which makes getting a good reading with my nits gun hard to do (LS-100).
How much light can I expect to go through an LCD module?
My name is Jon Proietti and I am an intern at a digital signage company. We've been looking into the possibility of using full color LCD displays outdoors. We want to increase the light output through the LCD so that it will be more easily visible in direct sunlight.
We purchased a large LCD television to play around with. Here is my understanding of how it's set up; please correct me if I am wrong.
At the very back is a series of white LEDs for the back light. 2" in front of them is a diffuser followed by two sheets of what I would call prism sheets. Their function seems to be directing the diffused light directly forward. There is a half inch of space before the LCD module, which I assume has the polarizer(s?) built in.
The original backlight put out roughly 6000 nits (cd/m2) and an all white message on the display allowed 280 nits through. Roughly 5%.
We built a jig and replaced the backlight with our own design, capable of 16000 nits. But somewhere in the process I lost a lot of throughput.
Code:
INPUT OUTPUT
NITS NITS
1694 28.6 1.69%
3442 57.8 1.68%
5131 81.63 1.59%
6780 106.8 1.58%
8390 131.2 1.56%
11040 165.3 1.50%
12320 188.3 1.53%
14070 212.1 1.51%
15250 236.5 1.55%
16750 259.4 1.55%
I'm not sure where I went wrong. Maybe it's that the jig is not enclosed and light is escaping. I know that some light is bouncing off of the diffuser. Maybe I need to enclose the jig with some reflective white surface to reflect the light back?
I've also considered that maybe I couldn't get an accurate reading of the original backlight LEDs. They are spaced about 3" apart, which makes getting a good reading with my nits gun hard to do (LS-100).
How much light can I expect to go through an LCD module?
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