Image projector with internally tiled intermediate images
View Patent ↗Disclosed are a system and method for microprojection that uses multiple imagers to produce a high resolution output image. Each of a set of imagers produces a portion of the final image. Relay lenses then tile the individual image portions together into a combined image. Because the height of the individual imagers is smaller than the height of a monolithic imager, they can fit into a very thin device. The combined image has a resolution equal to the sum of the resolutions of the individual imagers. The individual images are tiled together within the microprojector itself rather than on a projection screen. This allows the tiling to be adjusted once at the factory and set forever. In some embodiments, the light created for use by the microprojector is split by a polarizing beamsplitter. Each resultant polarized beam is then sent to an imager. Another polarizing beamsplitter combines the individual images.
1. An image projector comprising:
an illumination system configured for directing light along paths toward each of a plurality of imagers;
the plurality of imagers, each imager configured for creating an intermediate image in a light path;
a plurality of relay lenses, wherein for each imager, a relay lens is configured for relaying the intermediate image created by the imager in a light path toward a projection lens system, and wherein the intermediate images are tiled into a combined image; and
the projection lens system configured for projecting the combined image.
2. The image projector of claim 1 wherein the illumination system comprises a first polarizing beamsplitter configured for splitting light into a plurality of polarized-light paths, each polarized-light path leading toward an imager, wherein for each imager, a polarizing direction of the imager is aligned with incoming polarized light.
3. The image projector of claim 2 further comprising:
a second polarizing beamsplitter configured for combining light from the relay lenses and for directing the combination of light toward the projection lens system.
4. The image projector of claim 1 wherein the illumination system comprises a plurality of monochromatic light sources.
5. The image projector of claim 4 wherein each monochromatic light source is selected from the group consisting of: a light-emitting diode and a laser.
6. The image projector of claim 1 wherein the illumination system comprises a white-light source.
7. The image projector of claim 1 wherein a sum of vertical dimensions of the intermediate images, after relaying, is no greater than a vertical dimension of an imager.
8. The image projector of claim 1 comprising exactly two imagers and exactly two relay lenses.
9. The image projector of claim 1 wherein a resolution of the combined image is a sum of resolutions of the intermediate images.
10. The image projector of claim 9 wherein the resolution of the combined image is a product of a horizontal resolution of the combined image and a vertical resolution of the combined image, wherein the horizontal resolution of the combined image equals a horizontal resolution of each intermediate image, and wherein the vertical resolution of the combined image equals a sum of vertical resolutions of the intermediate images.
11. The image projector of claim 1 wherein each imager is selected from the group consisting of: a reflective imager and a transmissive imager.
12. The image projector of claim 1 further comprising:
a diffuser located in a light path where an intermediate image is created.