Two-stage projection architecture
View Patent ↗A two-stage light projection system is provided for projecting an image comprising a matrix of light pixels having modulated luminance. A first imager is configured to modulate a light band on a pixel-by-pixel basis proportional to gray scale values provided for each pixel of the image to provide a first output matrix. A second imager is positioned and configured to receive the first output matrix and modulate the individual modulated pixels of light from the first imager on a pixel-by-pixel basis proportional to a second gray scale value provided for each pixel. A relay lens system having a single-gauss lens set and a mirror positioned at the system stop focuses the modulated light output from the first imager on a pixel-by-pixel basis onto the corresponding pixels of the second imager.
1. A projection system for projecting an image comprising a matrix of pixels having modulated luminance, the projection system comprising:
a first imager configured to modulate a light band on a pixel-by-pixel basis proportional to gray scale values provided for each pixel of the image to provide a first output matrix;
a second imager positioned and configured to receive the first output matrix of modulated pixels of light and modulate the individual modulated pixels of light from the first imager on a pixel-by-pixel basis proportional to a second gray scale value provided for each pixel of the image; and
a relay lens system configured to focus the modulated light output from the first imager on a pixel-by-pixel basis onto the corresponding pixels of the second imager, the relay lens system including a single-gauss lens set and a mirror positioned at the system stop for the lens set to reflect the image back through the lens set.
2. The projection system of claim 1 wherein the relay lens system further comprises a quarter-wave plate disposed between the single-gauss lens set and the mirror.
3. The projection system of claim 2 further comprising first and second polarizing beam splitters disposed between the mirror and the second imager.
4. The projection system of claim 3 wherein the first polarizing beam splitter is also disposed between an illumination source and the first imager.
5. The projection system of claim 1 wherein the single-gauss lens set comprises a single spherical lens and an acromatic lens, wherein the acromatic lens is disposed between the single spherical lens and the system stop.
6. The projection system of claim 1 wherein the relay lens system has a distortion of less than about 0.05% with an optical transfer function of greater than 0.6 at a spatial frequency of 36 cycles per millimeter.
7. The projection system of claim 1 wherein the relay lens system has a magnification of between about −0.9995 and −1.0005.
8. The projection system of claim 1 wherein the relay lens system has a telecentricity with an input and output angle deviation of less than 1.05 degrees.
9. A two-stage projection system for projecting an image along a projection path, the projection system comprising:
first and second imagers, each comprising a matrix of pixels, with a mirror disposed in the projection path between the imagers and a single-gauss lens set having an optical axis on the projection path and disposed between the mirror and the imagers, such that the output of a first imager passes through the single-gauss lens set once in each direction along the optical axis of the single-gauss lens set focusing the output of a specific pixel of the first imager onto a corresponding pixel on the second imager.
10. The two-stage projection system of claim 9 wherein the first and second imagers are LCOS imagers and first and second polarizing beam splitters are disposed between the mirror and the second imager.
11. The two-stage projection system of claim 10 wherein the first polarizing beam splitter is simultaneously disposed between an illumination source and the first imager.
12. The two-stage projection system of claim 11 further comprising a quarter-wave plate disposed between the single-gauss lens set and the mirror.
13. The two-stage projection system of claim 9 wherein the single-gauss lens set comprises a single spherical lens and an acromatic lens, wherein the acromatic lens is disposed between the single spherical lens and the system stop.
14. The two-stage projection system of claim 9 wherein the single-gauss lens set has a distortion of less than about 0.05% with an optical transfer function of greater than 0.6 at a spatial frequency of 36 cycles per millimeter.
15. The two-stage projection system of claim 9 wherein the single-gauss lens set has a magnification of between about −0.9995 and −1.0005.
16. The two-stage projection system of claim 9 wherein the single-gauss lens set is telecentric with an input and output angle deviation of less than 1.05 degrees.
17. The two-stage projection system of claim 9 where the length of the projection system along its greatest dimension is less than 100 millimeters.