Scanned display with pinch, timing, and distortion correction
DCFirst Claim
1. A method of producing an image for viewing, comprising the steps of:
- emitting light from a first location;
resonantly scanning the light along a first axis at a first frequency;
scanning the light along a second axis different from the first axis at a second frequency, while scanning the light along the first axis;
scanning the light along the second axis at a third frequency that is an integral multiple of the first frequency, while scanning the light along the first axis; and
modulating the light in a pattern corresponding to the image, synchronously with the step of resonantly scanning the light along the second axis.
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Abstract
A display apparatus includes an image source that scans about two axes. To offset motion about a first of the axes during sweeps about the second axis, the apparatus includes a structure to produce offsetting motion about the first axis at a scanning rate equal to the twice-scanning rate about the second axis. The offsetting scan can be a ramp or other motion. In one embodiment, the offsetting motion is a resonant sinusoid. The offsetting motion may be produced by an auxiliary scanner such as a mechanical scanner, a piezoelectric scanner, a MEMs scanner or other scanner. Because the offsetting motion is very small, the auxiliary scanner can function with a very small scan angle.
182 Citations
47 Claims
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1. A method of producing an image for viewing, comprising the steps of:
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emitting light from a first location; resonantly scanning the light along a first axis at a first frequency; scanning the light along a second axis different from the first axis at a second frequency, while scanning the light along the first axis; scanning the light along the second axis at a third frequency that is an integral multiple of the first frequency, while scanning the light along the first axis; and modulating the light in a pattern corresponding to the image, synchronously with the step of resonantly scanning the light along the second axis. - View Dependent Claims (2, 3, 4, 5)
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6. A method of scanning a light beam in a substantially raster pattern, comprising the steps of:
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emitting, from a first position, the light beam; scanning the light beam about a first axis through a first angular range at a first rate with a first period; scanning the light beam about a second axis orthogonal to the first axis through a second angular range at a second rate; directing the emitted, scanned light toward the user'"'"'s eye; and scanning the light beam at a third rate at least as high as the first rate about the second axis at an amplitude selected to offset motion of the second scan during the first period. - View Dependent Claims (7, 8, 9, 10)
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11. A method of scanning an optical path through a substantially rectilinear pattern, comprising the steps of:
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scanning a first mirror periodically in a first direction at a first frequency, the first mirror being positioned to sweep the optical path about a first axis; scanning a second mirror continuously in a second direction while scanning the first mirror in the first direction, the second mirror being positioned to sweep the optical path about a second axis different from the first axis; producing a scanning signal at a second frequency that is twice the first frequency of the first frequency; and scanning a third mirror in response to the scanning signal, the third mirror being positioned to sweep the optical path about the second axis. - View Dependent Claims (12, 13, 14, 15, 16, 19)
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17. A method of scanning an optical path through a periodic pattern with a scanning system including a mechanically resonant scanner having a resonant frequency, comprising the steps of:
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scanning the optical path through a field of view at the resonant frequency along a first axis by activating the mechanically resonant scanner; scanning, at a frequency lower than the resonant frequency, the optical path along a second axis different from the first axis while performing the step of scanning the optical path along the first axis by activating the mechanically resonant scanner; determining an the amount of scan of the optical path along the second axis that occurs while the optical path scans once through the field of view; producing a driving signal at a correction frequency that is an integral multiple of the resonant frequency; and scanning along the second axis at the correction frequency and with an amplitude selected to offset the determined amount of scan. - View Dependent Claims (18)
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20. A scanner for scanning a beam of electromagnetic energy through a substantially raster pattern, comprising:
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a first scanning assembly having a first mirror configured to pivot about a first axis and a second mirror configured to pivot about a second axis orthogonal to the first axis; a second scanning assembly having a third mirror separate from the first mirror and the second mirror, the third mirror being pivotable about the first axis in response to a driving signal; a position sensor having a sensing input coupled to the first mirror and a sensing output, the position sensor being responsive to movement of the first mirror about the first axis to produce an electrical signal at the sensing output corresponding to the position of the first mirror; and a driving circuit having a signal input coupled to the sensing output and a driving output coupled to the second scanning assembly, the driving circuit being responsive to the electrical signal to produce the driving signal. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27)
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28. A scanning apparatus for scanning a beam in a substantially raster format, comprising:
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a first scanning assembly having a first optical input and a first scan signal input, the first scanning assembly being configured to scan an optical beam substantially sinusoidally at a first frequency about a first axis and to scan the optical beam about a second axis orthogonal to the first axis; and a corrective scanner positioned to receive the optical beam either before or after the first scanning assembly and configured to scan the beam about the second axis at a second frequency that is twice the first frequency. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40)
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41. An imager for acquiring data corresponding to a target object, comprising:
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a first scanning assembly having a first optical input and a first scan signal input, the first scanning assembly being configured to scan substantially at a first frequency about a first axis and to scan about a second axis different from the first axis; imaging optics aligned to the first scanning assembly and configured to collect light from the target object direct the gathered light along an optical path including the first scanning assembly; and a correction scanner positioned along the optical path and configured to redirect the gathered light along the second axis at a frequency and amplitude corresponding to an expected amount of scan of the first scanning assembly about the second axis during a half period of the first frequency. - View Dependent Claims (42, 43, 44, 45, 46, 47)
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Specification