Laser Diode Pin Orientation for Micro-Projector Speckle Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional laser-diode, liquid-crystal projectors suffer from speckle interference patterns due to the unique properties of laser light sources, which hinder their use in small, low-power micro-projectors.
Innovation Solution
The projector design incorporates elliptically shaped laser diodes for red, green, and blue light sources with perpendicular power application pins, a beam shaper to form a uniform light pattern, and a vibrating beam shaper to reduce speckle, along with a polarized beam splitter and projection lens to align polarization axes and enhance image clarity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a laser light source is used to achieve high luminous efficacy and low power consumption, then power efficiency is improved, but speckle interference patterns appear in the projected image
Solution Approach 1:
The patent applies the dynamics principle by vibrating the diffuser at frequencies between 50-200 Hz to dynamically change the speckle pattern over time. This vibration causes the speckle interference to fluctuate rapidly, making it imperceptible to the human eye while maintaining the high luminous efficacy of the laser light source
Solution Approach 2:
The patent implements periodic action through the oscillating vibration of the diffuser. The diffuser is driven to vibrate periodically at specific frequencies, creating time-varying speckle patterns that reduce the visibility of interference while preserving the energy efficiency benefits of laser illumination
2Object-affected harmful factors
If a diffuser is added to reduce speckle, then speckle interference is reduced, but the optical path length and device complexity increase
Solution Approach 1:
The patent merges the diffuser function with the existing optical path by positioning it between the laser light source and the liquid crystal panel. The diffuser is integrated into the illumination system rather than added as a separate external component, minimizing structural complexity while achieving speckle reduction
Solution Approach 2:
By making the diffuser oscillating rather than static, the patent reduces the need for additional complex optical components. The dynamic vibration of a single diffuser element achieves speckle reduction that would otherwise require multiple static optical elements or more complex optical arrangements
3Device complexity
If the diffuser is stationary, then the optical structure is simple, but speckle patterns remain visible in the image
Solution Approach 1:
The patent transforms the stationary diffuser into a dynamic oscillating component. The diffuser is driven to vibrate at controlled frequencies, which causes the speckle pattern to change rapidly over time. This dynamic approach maintains simple optical structure while effectively reducing visible speckle interference
Solution Approach 2:
The patent applies mechanical vibration to the diffuser to reduce speckle interference. The diffuser is mechanically oscillated at frequencies that create temporal variations in the speckle pattern, making it imperceptible to the human eye while maintaining the simplicity of the optical structure
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 configuration efficiently aligns polarization directions and reduces speckle interference, resulting in a clear and high-quality image projection with minimized power consumption, suitable for small-scale micro-projectors.
Implementation Method 1
a G laser diode for emitting green light of an elliptical shape elongated in a first direction, a B laser diode for emitting blue light of an elliptical shape elongated in the first direction, an R laser diode for emitting red light of an elliptical shape elongated in a direction perpendicular to the first direction
Implementation Method 2
a first beam shaper for transforming light emitted from the light source in a perpendicularly intersecting pattern into uniform light
Implementation Method 3
a vibrating beam shaper to reduce speckle
Implementation Method 4
a polarized beam splitter and projection lens to align polarization axes
Data Source
AI summary
The present invention relates to a laser-diode, liquid-crystal projector. In the present invention, a light source comprises a G laser diode emitting green light, a B laser diode emitting blue light, and an R laser diode emitting red light and provided such that a power application pin is positioned vertical to the power application pin of the G laser diode or B laser diode, and an optical structure appropriate therefor is proposed. According to the present invention, the directions of polarized lights of the R, G, and G light sources incident from an optical modulator formed from a liquid crystal can be consistent with each other by efficiently changing the arrangement of the pins of the laser diodes without using a separate complex optical element.