Servo feedback control based on designated scanning servo beam in scanning beam display systems with light-emitting screens
View Patent ↗Scanning beam display systems that scan one servo beam and an excitation beam onto a screen that emits visible light under excitation of the light of the excitation beam and control optical alignment of the excitation beam based on positioning of the servo beam on the screen via a feedback control.
1. A scanning beam display system, comprising:
a light module to direct and scan at least one excitation beam having optical pulses that carry image information and at least one servo beam at a servo beam wavelength different from a wavelength of the excitation beam;
a screen positioned to receive the scanning excitation beam and the servo beam, the screen comprising a light-emitting layer of parallel light-emitting stripes that absorb light of the excitation beam to emit visible light to produce images carried by the scanning excitation beam, wherein an excitation side of the parallel light-emitting stripes includes a plurality of diffusively reflective servo marks that are spaced apart from each other to diffusively reflect servo beam light to produce servo feedback light, areas between the diffusively reflective servo marks including a specularly reflective region to specularly reflect servo beam light; and
an optical servo sensor module positioned on an excitation side of the screen to receive diffusively reflected servo feedback light and to produce a servo feedback signal indicative of positioning of the servo beam on the screen,
wherein the light module is responsive to the servo feedback signal to adjust timing of the optical pulses carried by the scanning excitation beam while being scanned across the screen to control spatial positions of the optical pulses on the screen.
2. The system as in claim 1 , wherein the specularly reflective region is supported by a coextruded film.
3. The system as in claim 2 , wherein the specularly reflective region is part of the coextruded film.
4. The system as in claim 1 , wherein the diffusively reflective servo marks are surrounded by the specularly reflective region.
5. The system as in claim 1 , wherein the plurality of diffusively reflective servo marks are positioned between the parallel light-emitting stripes.
6. The system as in claim 5 , wherein the parallel light-emitting stripes are positioned on a viewer side of the specularly reflective region, and wherein the diffusively reflective servo marks are disposed on an excitation side surface of the specularly reflective region.
7. The system as in claim 6 , wherein the specularly reflective region is supported by a coextruded film.
8. The system as in claim 7 , wherein the specularly reflective region is part of the coextruded film.
9. The system as in claim 1 , further comprising one or more additional optical servo sensor modules.
10. The system as in claim 1 , wherein the servo beam is an IR beam.
11. The system as in claim 1 , wherein the parallel light-emitting stripes are made of phosphor materials.
12. A method for controlling a scanning beam display system, comprising:
scanning one or more excitation beams modulated with optical pulses to carry image information across a screen to excite parallel light-emitting strips to emit visible light which forms an image;
scanning a servo beam at an optical wavelength different from an optical wavelength of the one or more excitation beams, across the screen;
detecting light of the servo beam that is diffusively reflected from a diffusively reflective servo mark on the screen to obtain a servo signal indicative of positioning of the servo beam on the screen; and
in response to the servo signal, controlling the one or more scanning excitation beams to control spatial positions of the optical pulses on the screen.