Laser Light Source Segmentation for Luminance Control
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Solution Overview
Problem
Existing image projection apparatuses using laser light sources face interference between pulse-driven laser diodes and digitally driven light modulation elements, leading to suboptimal projection images when trying to adjust luminance.
Innovation Solution
An image projection apparatus with a controller that selectively activates and deactivates laser light sources to control luminance, using a combination of emission and non-emission light sources to modulate illumination light, allowing for precise adjustment of luminance while maintaining image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If pulse driving is used to adjust luminance of laser light sources, then luminance adjustment capability is improved, but interference with digital driving of light modulation element occurs and image quality deteriorates
Solution Approach 1:
The light source unit is divided into multiple independent laser light sources (first through fourth LDs). Instead of using pulse driving on a single LD, the controller selectively turns on or off individual LDs to adjust luminance. This segmentation allows luminance control without pulse interference, as each LD operates continuously when selected rather than being pulsed
Solution Approach 2:
The system dynamically switches between different combinations of laser light sources based on required luminance levels. The controller determines which LDs to activate in real-time, creating a dynamic luminance adjustment mechanism that avoids the static pulse driving approach and its associated interference problems
2Adaptability or versatility
If duty cycle adjustment of pulse driving is used to control luminance, then luminance control flexibility is improved, but digital driving interference increases and projection image quality worsens
Solution Approach 1:
The system segments the luminance control function across multiple laser light sources. Instead of adjusting duty cycle of a single pulsed LD, the controller achieves flexible luminance control by selecting different subsets of LDs to activate. This provides adaptability equivalent to duty cycle adjustment but without the harmful pulse interference
Solution Approach 2:
The patent replaces the pulse driving mechanism (temporal modulation) with a spatial selection mechanism (selecting which LDs to activate). This substitution eliminates the interference with digital light modulation while maintaining luminance control flexibility through combinatorial selection of light sources
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
Enables effective luminance adjustment of projection light without deteriorating image quality, even when the light modulation element is digitally driven, by strategically selecting which laser light sources to turn on or off among the plurality of laser light sources.
Implementation Method 1
a light source unit including a plurality of laser light sources
Data Source
AI summary
An image projection apparatus includes a light source unit including a plurality of laser light sources, a light modulation element configured to modulate illumination light generated using a laser beam from the light source unit and to generate image light projected onto a projection surface, and a controller configured to control driving of the plurality of laser light sources. The controller controls a luminance of the illumination light by selecting a first laser light source that emits the laser beam and a second laser light source that does not emit the laser beam among the plurality of laser light sources.