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How do I enlarge an image that's been projected onto a screen? Answered

I made this device that shines light through an LCD screen to project the image onto a window, which then reflects back to me, forming a sort of heads-up display.
The LCD screen is about the size of a credit card, and I can't move it any further than ~40cm from the window.
Another restriction is, any lens I use can't make the device any more than another 5cm thicker. (that includes distance between the lens and the screen)

Is it possible to make the image appear any larger using any lenses? I've tried those plastic magnifying sheets and a lens from a projector tv, but they don't seem to make much difference.




Best Answer 5 years ago

You only really have 2 options

1. Make the distance to the screen longer

2. Use a suitable lens - To spread the image over a short distance this should be a concave lens and may be difficult to source a suitable unit. Your convex lens you have tried will focus the image and magnify but in general your looking at magnifying glass lenses with typically 2 - 4 inches focal length - they need a good distance to give you a bigger picture.