Field Sequential Light Source Modulation for a Digital Display System

• US 20120327139A1
• Filed: 08/30/2012
• Published: 12/27/2012
• Est. Priority Date: 06/20/2005
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Digital Display Innovations, LLC
• Inventors: MARGULIS, Neal D.
• Granted Patent: US 8,698,701 B2
• Time in Patent Office: Days
• US Class Current: 345/690
• CPC Class Codes: G03B 21/005 Projectors using an electronic spatial light modulator but not peculiar thereto
• CPC Class Codes: G03B 21/2033 LED or laser light sources
• CPC Class Codes: G03B 21/206 Control of light source other than position or intensity
• CPC Class Codes: G03B 21/26 Projecting separately subsidiary matter simultaneously with main image
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 2310/024 Scrolling of light from the illumination source over the display in combination with the scanning of the display screen
• CPC Class Codes: G09G 2320/041 Temperature compensation
• CPC Class Codes: G09G 2320/045 Compensation of drifts in the characteristics of light emitting or modulating elements
• CPC Class Codes: G09G 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 2360/145 the light originating from the display screen
• CPC Class Codes: G09G 3/03 specially adapted for displays having non-planar surfaces, e.g. curved displays
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources
• CPC Class Codes: G09G 3/342 using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines
• CPC Class Codes: H04N 5/7416 involving the use of a spatial light modulator, e.g. a light valve, controlled by a video signal
• CPC Class Codes: H04N 9/312 Driving therefor driving of electronic spatial light modulators in displays other than projection devices G09G3/34, G09G3/36; control of liquid crystal elements G02F1/133; control of micromechanical modulators G02B26/08
• CPC Class Codes: H04N 9/3155 for controlling the light source light source control per se H05B35/00 – H05B47/00; control of an illumination source for displays in general G09G3/3406

Abstract

A digital display system consists of an image modulator and multiple light modulators. An image processing system processes an incoming data stream, scans processed data to an image modulator and controls for the light modulators. Other user inputs and sensors are used to affect the processing and controls. The timing for scanning the processed data into the image modulators is controlled along with the intensity and wavelength of the light modulators. The display system may implement a spatial and temporal image processing, digital shutter controls, rolling shutter controls, sequential color output, adaptive dynamic sensor feedback, frame rate matching, motion compensated field sequencing and a variety of other techniques to produce a high quality display output. The resulting display has improved image consistency, enhanced color gamut, higher dynamic range and is better able to portray high motion content.

Claims

1. A method of operating a field sequencing display, comprising:

positioning a plurality of light sources, each including at least three LEDs of different colors, at different locations in said display;

scanning pixel values for individually controllable pixels into an image modulator during each of multiple field intervals of an image frame period; and

receiving a processed data stream of values for incoming image frames and, in response to received values,

controlling said light sources to vary the brightness of said LEDs as a function of their locations in said display during each said field interval, and

controlling the light transmissions of said individually controllable pixels during each said field interval.

2. The method of claim 1 further comprising adaptively and dynamically compensating the brightness for one or more of said light sources in response to sensor feedback.

3. The method of claim 1 further comprising controlling the brightness for three or more different wavelength LEDs to vary the color of said one or more light sources in response to said processed data stream.

4. The method of claim 1 further comprising controlling the brightness for three or more different wavelength LEDs to vary the color of said one or more light sources in response to sensor feedback.

5. The method of claim 1 further comprising positioning said multiple light sources in two or more parallel bands, and setting values of said light sources to zero during a portion of said field interval.

6. The method of claim 1 further comprising spacing image modulator scanning times by a period of time based on a multiple of the frame rate of said processed data stream.

7. The method of claim 1 further comprising decomposing frames from said processed data stream into temporal fields;

sequentially scanning and displaying said temporal fields by said image modulator, and varying said brightness for the display of said sequential fields.

8. The method of claim 1 wherein said plurality of light sources illuminate a microdisplay of a projection display system.

9. A method of operating a display, comprising:

positioning at least one light source for each of three different wavelengths of light at different locations in said display;

providing, for each light source, a respective light source control for dynamically varying the brightness of the respective light source as a function of its location in said display;

scanning a field of data which makes up part of a frame into individually controllable pixels of an array in an image modulator during an image modulator scanning time; and

using a controller for

receiving a stream of processed data values for incoming frames based on which said controller

controls the values for said individually controllable pixels,

controls said light sources to vary the brightness for said different wavelengths at multiple locations of said display, and

sequences two or more of said fields of data for each incoming frame.

10. The method of claim 9 further comprising setting the brightness of said light sources to zero for some time during each said image modulator scanning time.

11. The method of claim 9 further comprising adjusting the brightnesses of said light sources one or more times while sequencing each of said fields.

12. The method of claim 9 further comprising spacing said image modulator scanning times by a period of time that is varied based on a rate of said incoming frames in said stream of processed data values.

13. The method of claim 9 wherein the combination of said three different wavelengths of light are varied during said modulator scanning time.

14. The method of claim 9 further comprising using the rate of said incoming frames to proportionally match the sequencing time for said display fields so that an outgoing frame rate is an integer multiple of an incoming frame rate.

15. The method of claim 9 further comprising spacing said image modulator scanning times by a period of time that is varied based on the motion of one or more objects within said processed data stream.

16. A method of displaying images on a flat panel display, comprising:

positioning three or more different wavelength LED light sources at different locations in said display;

separately, by light source controls, varying brightnesses of said light sources within different regions of said display;

scanning pixel values into individually controllable pixels in an image modulator array having a modulator resolution, during an image modulator scanning time; and

using one or more controllers for

receiving an input data stream containing image data,

spatial processing image data for a display frame into three or more image color fields each corresponding to a different wavelength,

filtering said image color fields to match said image modulator resolution, and

filtering image data to a light source resolution, lower than said image modulator resolution, for controlling said LED light sources;

wherein each of said image color fields has both a duration and an LED color combination which can be varied by said light source controls switching LEDs for successive color fields.

17. The method of claim 16 further comprising:

sequencing, by said one or more controllers, said image color fields to correspond to a sequence of image modulator pixel values such that image modulator data sets can each vary with different light source color fields, and

cycling LEDs of equal wavelength with a rolling shutter.

18. The method of claim 16 further comprising (adaptively and dynamically) compensating brightness of one or more of said light sources based on their positions relative to the display screen, and varying controls of said image modulator, in response to sensor feedback.

19. The method of claim 16 further comprising controlling brightnesses and durations of illumination of three or more different wavelength LED arrays, based on each array'"'"'s position relative to said display, to vary composite colors of said light sources in response to sensor feedback.

20. The method of claim 16 further comprising synchronizing spatial processing image data into color fields with using said sequential fields to modulate pixel fields, and wherein LEDs for a given wavelength are not cycled all at once but used with a rolling shutter.