Scanning Projector Guard Bands Reduce Color Shifts

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Scanning projectors experience color shifts due to inter-pixel interference at the beginning and end of each pixel period, which is not effectively addressed by existing technologies.

Innovation Solution

The implementation of guard timing bands and multiple pulses per pixel period to control the intensity and timing of red, green, and blue light emitting elements, reducing inter-pixel interference and color shifts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If guard bands are introduced to reduce inter-pixel interference, then color shift is reduced, but the effective pixel duty cycle is reduced

Engineering Contradiction:

Improvecolor accuracyVSAvoidpixel duty cycle

Core Design Contradiction:

Manufacturing precisionVSDuration of action of moving object

Solution Approach 1:

The pixel period is segmented into multiple sub-periods with multiple pulses for each color (R, G, B). This allows the guard band to be distributed across multiple smaller intervals rather than requiring a single large guard band, thereby reducing the total time lost to guard bands while maintaining color accuracy through multiple sampling points.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Multiple pulses are applied periodically within each pixel period, with each pulse separated by sub-periods. This periodic structure allows the system to maintain color accuracy through repeated sampling while reducing the cumulative guard band time compared to a single pulse approach.

Inventive Principle:

Principle #19Periodic action

2Manufacturing precision

If multiple pulses per pixel period are used to reduce color shifts, then color accuracy is improved, but device complexity increases

Engineering Contradiction:

Improvecolor accuracyVSAvoidcontrol complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The control signal is segmented into multiple pulses per pixel period, with each pulse controlling a specific color channel independently. This segmentation allows for simpler individual pulse control while achieving better overall color accuracy through cumulative effect, reducing the complexity compared to a single complex pulse system.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The periodic pulse structure follows a regular pattern that can be implemented through standard timing control mechanisms. The repetitive nature of multiple pulses per period simplifies the control logic compared to asymmetric or irregular pulse patterns, maintaining device simplicity while improving color accuracy.

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS9503701B2Scanning projectors that use guard bands to reduce color shifts, and methods and controllers for use therewith

Publication Date: 2016.11.22 INTERSIL AMERICAS INC

AI summary

A scanning projector system includes a controller, a driver and one or more micro-mirror(s). The controller produces first, second and third pixel data in dependence on a video signal. The driver drives first, second and third light emitting elements in dependence on the first, second and third pixel data produced by the controller, to thereby emit light of first, second and third colors. The micro-mirror(s) project an image in dependence on light beams produced in dependence on the light of the first, second and third colors. To reduce color shifts due to inter-pixel interference, the controller and/or driver causes at least one timing guard band per pixel period associated with each instance of the pixel data.