Another LED Projector Plan

[kreston]

Materials :
- 4* SSC P7 C-Bin LED Emitter (Max 900lm each, Thus 3600lm)
- 4-LED Reflector for Cree Emitters
- 4* 21mm*7.3mm Acrylic Lens (F ~= 10mm)
- A concave lens (F = -75mm Dia = 50mm)

Ok here is the plan :

An externally hosted image should be here but it was not working when we last tested it.

Explanation & Calculation

Leds working through driver. They're all fine 🙂 Rays going through reflector and reaching Acrylic lens(of course its convex by the way)
Because Leds are positioned in the focal point of acrylic lens(1cm), Rays going parallel.
If this part is wrong I think there must be a way to set leds so rays will go parallel. It shouldn't be impossible 🙂
Rays reaching the concave lens. Because they're coming parallel they're refracting like they're coming from concaves focal point.

So heres the calculation : Concave lens FL is = 75 mm. Concaves diameter = 50mm Fresnels Fl = 120mm And fresnels height is 90mm

An externally hosted image should be here but it was not working when we last tested it.

We want to know if the ray is sufficient for fresnel or reaches the fresnels height

X = 4 So that means its not reaching. x*2 = 8cm
8cm means the full height
LCD's height = 77mm so its okay.

What do you think?

 

[reedlaw]

Have you tried this yet? I am interested in building a LED projector.