Micromirror Actuator Duty Cycle Synchronization

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Solution Overview

Problem

The existing operation of micromirror actuators in motor vehicle lighting devices results in visible flashing and dimming due to uniform duty cycles, leading to unwanted shifts in brightness and limited dynamic range of light intensity.

Innovation Solution

A device and method that dynamically adjust the duty cycle of micromirror actuators by introducing a waiting period to synchronize switching with image content, allowing for real-time adjustments in illuminance levels without loss of display quality, achieved through a processor-controlled system that embeds switching requests within the image stream and utilizes a reserved control channel for efficient transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the duty cycle is switched to adjust illuminance levels, then the dynamic range of light intensity is improved, but visible flashing and brightness shifts occur

Engineering Contradiction:
Improvedynamic range of light intensityVSAvoidvisible flashing and brightness shifts
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by calculating and preparing adjusted pixel values in advance based on the upcoming duty cycle change. Before the duty cycle switch occurs, the system computes the scaled pixel values that will compensate for the brightness change, ensuring that when the duty cycle actually switches, the brightness remains stable without visible flashing or shifts.

Inventive Principle:
Principle #10Preliminary action

2Ease of operation

If the duty cycle is switched during continuous operation, then real-time control flexibility is improved, but synchronization issues cause unwanted brightness shifts

Engineering Contradiction:
Improvereal-time control flexibilityVSAvoidbrightness stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The patent implements feedback by continuously monitoring the duty cycle value and using this information to dynamically adjust pixel values. The system establishes a feedback loop where the current duty cycle state informs the scaling factor applied to pixel values, ensuring that brightness stability is maintained through real-time adaptive compensation based on the actual duty cycle being used.

Inventive Principle:
Principle #23Feedback

3Stability of the object's composition

If a waiting period is introduced to synchronize duty cycle switching, then brightness stability is improved, but switching response time increases

Engineering Contradiction:
Improvebrightness stabilityVSAvoidswitching response time
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The patent resolves this contradiction by performing the pixel value adjustment calculations in advance, during the waiting period, rather than after synchronization is achieved. This preliminary calculation of scaled pixel values ensures brightness stability while the system prepares in advance, and when the actual switching occurs, the compensation is already in place, minimizing the perceptible delay.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3705926B1Method and device for operating a control unit of a micro-mirror actuator
Publication Date: 2024.09.18 MARELLI GERMANY GMBH
  • EP3705926B1 patent drawingFigure 1
  • EP3705926B1 patent drawingFigure 2
  • EP3705926B1 patent drawingFigure 3

AI summary

A method for operating a control unit (4) of a micromirror actuator (210) is provided, the method comprising: providing an image stream (VS) for the control unit (4), determining individual frames of the image stream (VS) depending on the validity of a first value (DC1) of a basic duty cycle, which is effective for a plurality of micromirrors of the micromirror actuator (210), determining a switching request (S) to switch the basic duty cycle to a second value (DC2), transmitting the switching request (S) at a first time (t1) towards the control unit (4), and determining the individual frames of the image stream (VS) from a second time (t2), which occurs from the first time (t1) after a waiting period (T1), depending on the validity of the second value (DC2) of the basic duty cycle.