Claims
- 1. A high efficiency prism for directing one or more color components of light to generate a color image, the prism comprising:
an input polarizing beam splitter for separating incoming unpolarized light into a beam having a first polarization and a beam having a second polarization; a first color selection layer at the exit point of the first polarization beam for transmitting a first color light; a first color polarizing beam splitter into which the first color light is received, the first polarizing beam splitter directing the first color light towards a first color microdisplay; the first color microdisplay reflecting the first color light and changing its polarization to generate an altered first color beam; a second color selection layer at the exit point of the second polarization beam for transmitting the second and third color light; a second and third color polarizing beam splitter that receives the second and third color light, the second and third color polarizing beam splitter for directing the second color light towards a second microdisplay and for directing the third color light towards a third microdisplay; the second microdisplay reflecting the second color light and changing its polarization to generate an altered second color light; the third microdisplay reflecting the third color light and changing its polarization to generate an altered third color light; an output polarizing beam splitter into which the altered first color beam, the altered second color beam and the altered third color beam are received, the third polarizing beam splitter recombining the altered color beams to generate a full color beam and directing the full color beam to an output.
- 2. The prism of claim 1 further comprising a dump light unit that discards unwanted light beams so that they do not become trapped in the prism and heat the prism.
- 3. The prism of claim 2, wherein the dump light unit further comprises a light path that directs unwanted light reflected by the color selection layers back into a light source so that the reflected unwanted light does not heat the prism.
- 4. The prism of claim 3, wherein the dump light unit further comprises a first light stop associated with the input polarizing beam splitter that absorbs unwanted light reflected by the color selection layers, a second light stop attached to the first color polarizing beam splitter that absorbs unwanted reflected light from the polarizing beam splitter and a third light stop attached to the output polarizing beam splitter that absorbs unwanted reflected light from the polarizing beam splitter.
- 5. The prism of claim 4, wherein the first light stop is separated from the input polarizing beam splitter by an air gap so that any heating of the first light stop by the light being absorbed does not heat the input polarizing beam splitter.
- 6. The prism of claim 1 further comprising a quarter waveplate inserted between each microdisplay and the corresponding polarizing beam splitter wherein the quarter waveplate increases the contrast ratio of the prism.
- 7. The prism of claim 6, wherein the first color selection layer comprises a green dichroic layer, the second color selection layer comprises a magenta dichroic layer, the first microdisplay reflects green light, the second microdisplay reflects blue light and the third microdisplay reflects red light.
- 8. The prism of claim 1, wherein the input polarizing beam splitter further comprises a first portion and a second portion that are offset from each other to correct the path lengths of the light components in the prism and wherein the elements of the prism are spaced apart from each other to correct the path lengths of the light components.
- 9. The prism of claim 6 further comprising a spacer glass located on each side of the quarter waveplates that corrects the light path lengths of the color components.
- 10. The prism of claim 1 further comprising a fourth microdisplay attached to the first color polarizing beam splitter that reflects the second color component having a different polarization and wherein the first color selection layer selects the first color light and the second color light.
- 11. The prism of claim 1, wherein the input polarizing beam splitter and the first color polarizing beam splitter are separated from each other by an air gap.
- 12. A high efficiency prism for directing one or more color components of light to generate a color image, the prism comprising:
an enclosure; a first polarized beam splitter element attached to the enclosure; a second polarized beam splitter element attached to the enclosure at substantially a right angle to the first polarized beam splitter element, the first and second polarized beam splitter elements separating the enclosure into four equal portions; each portion further comprising a wall region in between the two polarized beam splitter elements, each wall region further comprising a color selection layer; the enclosure having one or more transparent windows in the walls of the enclosure; a first microdisplay connected to a window for reflecting light having a first color; a second microdisplay connected to another window for reflecting light having a second color; and a third microdisplay connected to another window for reflecting light having a third color.
Parent Case Info
[0001] This application claims the benefit of the following U.S. Provisional Applications: U.S. Provisional Application Nos. 60/192,258 filed Mar. 27, 2000 and 60/225,242 filed Aug. 15, 2000. All of these provisional applications are hereby incorporated by reference in their entireties.
Provisional Applications (2)
|
Number |
Date |
Country |
|
60192258 |
Mar 2000 |
US |
|
60225242 |
Aug 2000 |
US |