Micromirror Bit-Plane Timing for High-Frame-Rate Color Depth

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

High frame rates in spatial light modulators, such as digital micromirror devices, result in micromirror settling time distortions during the least significant bit-planes, leading to visible distortion and limited color depth capabilities in displays like Near Eye Displays.

Innovation Solution

The process involves extending the time for the least significant bit-plane and reducing the light source output during these bit-planes, incorporating a break-before-make time to allow for micromirror settling, and using lower magnitude driving signals to improve accuracy and reliability of light output.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If high frame rates are used in spatial light modulators, then productivity is improved, but manufacturing precision deteriorates due to micromirror settling time distortions

Engineering Contradiction:

Improveframe rateVSAvoidcolor depth accuracy

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by extending the display time of the least significant bit-plane before micromirrors need to settle for the next bit-plane. This creates a buffer period that allows micromirrors to complete their settling motion before the next switching event, thereby eliminating settling time distortions while maintaining high frame rates.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent segments the bit-plane display sequence by inserting additional display periods between bit-planes, particularly extending the least significant bit-plane duration. This segmentation allows the system to accommodate micromirror settling times within the overall frame structure without reducing the frame rate, thus resolving the contradiction between productivity and manufacturing precision.

Inventive Principle:

Principle #1Segmentation

2Manufacturing precision

If display time for least significant bit-plane is extended, then manufacturing precision is improved, but loss of time increases

Engineering Contradiction:

Improvelight output accuracyVSAvoidbit-plane display time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent applies dynamics by selectively extending only the least significant bit-plane display time while keeping other bit-plane durations optimized. This dynamic adjustment ensures that the additional time is invested only where necessary (at the LSB where settling distortions are most problematic) rather than uniformly across all bit-planes, minimizing the overall time penalty.

Inventive Principle:

Principle #15Dynamics

3Manufacturing precision

If light source output is reduced during least significant bit-planes, then manufacturing precision is improved, but illumination intensity decreases

Engineering Contradiction:

Improvelight output accuracyVSAvoidbrightness

Core Design Contradiction:

Manufacturing precisionVSIllumination intensity

Solution Approach 1:

The patent applies local quality by reducing the light source output specifically during the least significant bit-plane period rather than uniformly across all bit-planes. This localized adjustment targets the specific time window where settling distortions occur, improving light output accuracy at the LSB while maintaining normal illumination intensity for other bit-planes where high precision is less critical.

Inventive Principle:

Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach achieves accurate and reliable light output, enabling higher color depths with minimal brightness reduction and efficient power usage, even at high frame rates.

Implementation Method 1

Each micromirror has an ON state where light is reflected to projection optics for projection and an OFF state where light is reflected away from the projection optics

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 2

The eye integrates the light from when the micromirror is ON to perceive the desired light intensity

Methodology Applied

Scientific EffectLight integration: Absorption (EM radiation)

Data Source

PatentUS20250298239A1Circuit and method for increased bit depth in high frame rate applications

Publication Date: 2025.09.25 TEXAS INSTRUMENTS INC

AI summary

Described examples include a process that includes illuminating a spatial light modulator at a first illumination level during a first bit-plane and stopping illumination at a beginning of a second bit-plane subsequent to the first bit-plane. The process also includes resuming illumination after a settling period of the spatial light modulator at a second illumination level for a time period such that a total illumination energy during the second bit-plane is equivalent to an intended illumination energy for the second bit-plane at the first illumination level and stopping illumination at the second illumination level before a subsequent third bit-plane.