Projection Device Laser Light Emission Delay Compensation
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Solution Overview
Problem
Projection devices using semiconductor laser elements experience light emission delays, leading to color unevenness and increased power consumption due to differing rise times among red, green, and blue laser elements, particularly when projecting pure white images.
Innovation Solution
A projection device with a controller that adjusts the output of laser light based on the specific rise times of each semiconductor laser element, ensuring synchronized light emission by controlling the driving current and scanning ranges to compensate for individual delays, thereby maintaining color balance and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If auxiliary current is added to compensate for light emission delay, then light emission delay is compensated, but power consumption increases
Solution Approach 1:
The controller starts the driving current to the semiconductor laser element earlier than the actual light emission timing, specifically starting the red laser driving current 1.0ms before the green laser and 1.5ms before the blue laser. This preliminary action allows the laser element to generate carriers in advance, compensating for the light emission delay without requiring additional auxiliary current during operation, thus avoiding increased power consumption.
2Productivity
If multiple semiconductor laser elements emit light simultaneously, then white image projection is achieved, but color unevenness occurs due to different rise times
Solution Approach 1:
The controller implements staggered start timing for different laser elements, starting the red laser 1.0ms before green and 1.5ms before blue, and adjusting current increases in stages. This ensures all lasers reach their target light output simultaneously despite different rise times, achieving uniform white color without compromising projection efficiency.
Solution Approach 2:
The controller dynamically adjusts the driving current parameters for each laser element based on their specific rise time characteristics. Red laser current is increased 0.5ms after start, green laser current is increased 0.3ms after start, and blue laser current is increased 0.8ms after start. These parameter changes ensure synchronized light emission and uniform color output.
3Speed
If driving current is increased to reduce rise time, then light emission speed improves, but light amount overshoots and becomes difficult to control
Solution Approach 1:
The controller implements dynamic, multi-stage current adjustment rather than a single fixed current level. The driving current starts at a base level and increases in stages at specific time points (0.5ms for red, 0.3ms for green, 0.8ms for blue after start). This dynamic approach allows the system to achieve fast light emission while maintaining precise control over the final light amount, avoiding overshoot.
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
The solution effectively reduces color unevenness and power consumption by synchronizing the light emission of semiconductor laser elements, ensuring consistent image quality and efficient operation.
Implementation Method 1
a plurality of light sources respectively emitting a laser light
Implementation Method 2
multiple types of semiconductor laser elements, such as red, green, and blue
Data Source
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AI summary
A projection device (101) is provided, which is capable of suppressing or preventing problems that result from a light emission delay of a light source (21a∼21c). The projection device (101) includes a plurality of light sources (21a∼21c) having a first light source and a second light source respectively emitting a laser light, and a time for the first light source to output a predetermined light amount is longer than that for the second light source (21a∼21c); a scanning part (3) enabling the laser light to scan; and a controller (58) controlling an output of the laser light.