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US 6,445,362 B1Granted
Scanned display with variation compensation
AssigneeMicrovision, Inc.
InventorClarence T. Tegreene
Life of this patent
Estimating the term…
Abstract
A display apparatus includes a scanning assembly that scans about two or more axes, typically in a raster pattern. A light source emits light toward the scanning assembly such that the scanning assembly simultaneously scans more than one of the beams. The light source is positioned such that its beam illuminates a discrete region of the image field. The image may be formed from a set of“tiles” where a single sweep of the scanning assembly scans a plurality of beams simultaneously. Various approaches to controlling the intensity of the light to compensate for variations in light source response or optical system response, or to balance the response of a tiles system are described. Among these approaches are scaling data in a buffer, active multiplication, or control of a D/A converter.
Claims41
A device for displaying an image having first and second image portions in response to an image signal, comprising:
- a first light source responsive to a first input signal to emit a first modulated light beam along a first light path relative to the first light source;
- a scanner having an input positioned along the first light path, the scanner being operative to receive the first modulated light beam and to redirect the first modulated light beam through a selected scan path toward a first image region in which the first modulated light beam defines a first image portion;
- and
- electronic control circuitry having an input port for receiving the image signal and a first output coupled to the first light source, the control circuitry being responsive to the image signal to produce the first input signals, the control circuit further including:
- an error circuit responsive to a determined error in the first modulated beam intensity to produce an error signal;
- a correction circuit having an input coupled to the error circuit, the correction circuit being responsive to the error signal to adjust the first input signal to reduce the determined error;
- and
- an error circuit including a buffer containing correction data, and wherein the correction circuit includes an electronic multiplier.
5 more elements
A device for displaying an image having first and second image portions in response to an image signal, comprising:
- a first light source responsive to a first input signal to emit a first modulated light beam along a first light path relative to the first light source;
- a scanner having an input positioned along the first light path, the scanner being operative to receive the first modulated light beam and to redirect the first modulated light beam through a selected scan path toward a first image region in which the first modulated light beam defines a first image portion;
- and
- electronic control circuitry having an input port for receiving the image signal and a first output coupled to the first light source, the control circuitry being responsive to the image signal to produce the first input signals, the control circuit further including:
- an error circuit responsive to a determined error in the first modulated beam intensity to produce an error signal;
- a correction circuit having an input coupled to the error circuit, the correction circuit being responsive to the error signal to adjust the first input signal to reduce the determined error;
- and
- a clock circuit responsive to the image signal to produce a nonuniform clock signal having a nonuniformity corresponding to an expected nonlinearity of the scanning mirror scan.
5 more elements
A device for displaying an image having first and second image portions in response to an image signal, comprising:
- a first light source responsive to a first input signal to emit a first modulated light beam along a first light path relative to the first light source;
- a scanner having an input positioned along the first light path, the scanner being operative to receive the first modulated light beam and to redirect the first modulated light beam through a selected scan path toward a first image region in which the first modulated light beam defines a first image portion;
- electronic control circuitry having an input port for receiving the image signal and a first output coupled to the first light source, the control circuitry being responsive to the image signal to produce the first input signals, the control circuit further including:
- an error circuit responsive to a determined error in the first modulated beam intensity to produce an error signal;
- a correction circuit having an input coupled to the error circuit, the correction circuit being responsive to the error signal to adjust the first input signal to reduce the determined error;
- an electronically controllable mass carried by the scanning mirror, the electronically controlled mass being responsive to an electrical signal to move relative to the mirror;
- and
- a scanner with a resonant oscillatory frequency, further including a sensor operative to produce an sensor signal indicative of mirror movement, and wherein the electronic control circuitry is coupled to receive the sensor signal and to vary the electrical signal in response thereto.
5 more elements
A device for displaying an image having first and second image portions in response to an image signal, comprising:
- a first light source responsive to a first input signal to emit a first modulated light beam along a first light path relative to the first light source;
- a scanner having an input positioned along the first light path, the scanner being operative to receive the first modulated light beam and to redirect the first modulated light beam through a selected scan path toward a first image region in which the first modulated light beam defines a first image portion;
- electronic control circuitry having an input port for receiving the image signal and a first output coupled to the first light source, the control circuitry being responsive to the image signal to produce the first input signals, the control circuit further including:
- an error circuit responsive to a determined error in the first modulated beam intensity to produce an error signal;
- a correction circuit having an input coupled to the error circuit, the correction circuit being responsive to the error signal to adjust the first input signal to reduce the determined error;
- and
- a second light source responsive to a second input signal to emit a second modulated light beam along a second light path relative to the second light source, the second light source being oriented such that scanner is in the second light path and wherein the scanner is operative to redirect the second modulated light beam toward a second image region in which the second modulated light beam defines a second image portion, and wherein the orientation of the first and second light sources is selected such that the first and second regions are substantially non-overlapping.
4 more elements
A device for providing a selected image at a viewing location in response to an image signal, comprising:
- a light source responsive to an input signal to emit an optical beam modulated according to the respective input signal, the light source having a variable intensity versus input signal response;
- a scanning assembly positioned to receive the modulated optical beam and operative sweep the modulated beam through a corresponding region of the viewing location to produce the image;
- and
- a correction circuit having an input terminal for receiving the image signal and an output port coupled to the light source, the correction circuit being responsive to the image signal and to variations in the intensity versus input signal response to produce the input signal that is not a constant function of the image signal.
1 more element
A method of producing an image for viewing with a scanning display having a light emitter in response to an image signal representing a desired image, the light emitter having a response that varies as a function of patterns in the image, comprising the steps of:
- identifying a nominal driving signal corresponding to the desired image;
- responsive to the image signal, predicting a variation in the light emitter response;
- producing an electrical signal indicative of the predicted variation;
- responsive to the identified nominal driving signal and the electrical signal indicative of the predicted variation, producing a corrected driving signal;
- responsive to the corrected driving signal, producing a light beam that is modulated according to the corrected driving signal;
- and
- scanning the light beam through a selected scan pattern to produce the image.
4 more elements
A display apparatus for viewing an image in response to an image signal, comprising:
- a scanning system having a light input and a light output;
- a modulated light source, including:
- a light emitter having an electrical signal input and being responsive to an input signal at the signal input to produce modulated light having an intensity corresponding to the input signal;
- and
- an electronic controller having an image input for receiving the image signal and a signal output coupled to the signal input of the light emitter, the electronic controller including a memory buffer for storing data corresponding to the image signal, a weighting circuit coupled to the memory buffer and operative to determine a correction factor in response to the stored data, and a multiplier circuit coupled to the memory buffer, the weighting circuit, and the signal output, the multiplier circuit being responsive to the stored data and the correction factor to produce the input signal at the signal output.
2 more elements
An apparatus for compensating for variations in a light power versus current response of a light emitter in a scanning display, comprising:
- an intensity monitor optically coupled to the light emitter;
- a reference signal source that provides a reference signal indicative of a desired intensity;
- a comparing circuit coupled to the intensity monitor in the reference signal source and operative to produce an error signal indicative of the difference between a monitored intensity and the desired intensity;
- and
- a correction circuit having a first input coupled to the comparing circuit, a second input configured to receive a driving signal for the light emitter, and a correction circuit output coupled to the light emitter, the correction circuit being responsive to the error signal and the driving signal to produce a corrected driving signal at the correction circuit output.
2 more elements
A method of stabilizing light intensity in a display, comprising steps of:
- producing a drive current in response to an input signal;
- determining a desired intensity of light in response to the input signal;
- monitoring an actual intensity of light produced in response to the drive current;
- determining a deviation between the monitored actual intensity of the light and the desired intensity of light;
- and
- scaling the drive current in response to the determined deviation.
3 more elements
A method of compensating for pattern dependent heating in a scanning beam display, comprising:
- receiving an input signal representing a desired image for display;
- storing in a memory device a digital representation of a portion of the input signal;
- retrieving a first set of data from the memory device;
- predicting a thermal effect in response to the retrieved first set of data;
- retrieving a second set of data from the memory device, the retrieved data representing a selected image portion;
- determining a drive signal in response to the second set of data;
- and
- adjusting the drive signal in response to the predicted thermal effect.
5 more elements
Dependencies are inferred from the claim text.