Laser Driver Current Control for True-Black Display Output
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Solution Overview
Problem
Conventional laser drivers consume power even for black pixels due to constant threshold current, leading to reduced contrast ratio and unnecessary power consumption.
Innovation Solution
A laser driver system that controls current to laser diodes based on pixel values, providing zero current for black pixels and non-zero current for non-black pixels, using a controller with digital-to-analog converters to manage threshold and data currents independently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If constant threshold current is provided to laser diode for all pixels, then laser diode can respond quickly to pixel transitions, but power consumption increases and contrast ratio deteriorates due to light projection for black pixels
Solution Approach 1:
The patent implements dynamic threshold current adjustment by detecting transitions between black and non-black pixels. The threshold current is enabled only when a black-to-non-black transition is detected, and disabled for black pixels. This dynamic control allows the laser driver to maintain fast response capability when needed while eliminating unnecessary power consumption during black pixel display, directly resolving the contradiction between speed and energy use.
2Ease of operation
If constant threshold current is provided to laser diode, then laser driver operation is simplified, but contrast ratio is reduced due to unwanted light projection for black pixels
Solution Approach 1:
The patent employs feedback mechanisms through transition detection logic that monitors pixel value changes. When a black-to-non-black transition is detected, the system activates threshold current; when black pixels are detected, threshold current is deactivated. This feedback-based control ensures high contrast ratio by preventing light projection during black pixels while maintaining operational simplicity through automated transition management, resolving the contradiction between ease of operation and illumination quality.
3Loss of energy
If threshold current is disabled for black pixels, then power consumption is reduced and contrast ratio is improved, but additional transition detection logic is required
Solution Approach 1:
The patent implements preliminary action by detecting pixel transitions in advance and proactively enabling or disabling threshold current before the actual pixel rendering occurs. The transition detection logic identifies upcoming black-to-non-black transitions and prepares the threshold current accordingly, allowing the system to achieve low power consumption and high contrast ratio while managing complexity through predictive control rather than reactive adjustments.
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
Reduces power consumption and enhances contrast ratio by eliminating light projection for black pixels, improving user experience and reducing power requirements.
Implementation Method 1
using a controller with digital-to-analog converters to manage threshold and data currents independently
Data Source
AI summary
A laser system comprising laser driver/s and controller/s which receive/s, from a pixel source, black and non-black pixel values each associated with a time interval, each including color component/s, and responsively, controls the laser driver to provide, to the laser diode: non-zero current during a first time interval associated with non-black pixel value/s and zero current during a second time interval associated with black pixel value/s. The laser diode thus projects light during the first time interval but not during the second time interval, yielding a display including non-black regions corresponding to non-black pixel values and true-black regions corresponding to black pixel values.