Laser Beam Shaping for Uniform Spot Size in Projectors
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Solution Overview
Problem
Projectors using laser beams face constraints due to varying distances between the projector and screen, resulting in non-uniform spot sizes across the screen as different incident angles and beam sizes affect each pixel, leading to image quality issues.
Innovation Solution
A projector design that includes a laser light source and shaping section configured for two-dimensional scanning, using the tip of the laser beam corresponding to cross-sections at various positions of the tapered portion to the beam waist, ensuring uniform spot sizes across the screen by adjusting the beam size and incident angle based on the projection distance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If only the portion of the laser beam where the beam size increases as the distance from the optical emitting surface increases is used, then the projector can be used at variable distances from the screen, but the beam size decreases as distance increases in other portions, causing design constraints and non-uniform spot sizes
Solution Approach 1:
The patent divides the laser beam into multiple segments along its propagation direction, utilizing different portions of the beam (increasing size portion, decreasing size portion, and waist portion) for different projection distance scenarios. This segmentation allows the system to maintain uniform spot sizes across the screen regardless of projection distance by selecting appropriate beam segments.
Solution Approach 2:
The patent implements dynamic selection of laser beam portions based on the projection distance. The beam selection is not fixed but adapts dynamically to the required projection distance, switching between increasing size portions, decreasing size portions, and waist portions to maintain optimal spot size uniformity across the screen.
2Adaptability or versatility
If the laser beam portion with increasing beam size is used, then projection is possible at any distance, but incident angles of the laser beam to each pixel on the screen are different, causing large variation in spot size
Solution Approach 1:
The patent applies different portions of the laser beam to different regions of the screen based on local requirements. By selecting specific beam portions (increasing, decreasing, or waist) that match the local incident angle and projection distance characteristics of each screen region, the system achieves uniform spot sizes across all pixels despite varying incident angles.
Solution Approach 2:
The patent changes the parameters of the laser beam (specifically which portion of the beam is used) to match the required projection conditions. By adjusting the beam selection parameter based on projection distance and screen position, the system maintains consistent spot sizes across the entire screen area.
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 allows for uniformization of spot sizes across the screen, improving image quality by maintaining consistent pixel sizes regardless of the projector-screen distance, effectively addressing the constraints of existing projector designs.
Implementation Method 1
a laser light source, a shaping section configured to shape a laser light emitted from the laser light source
Implementation Method 2
a graph of beam propagation characteristic illustrating a relationship between beam size of the laser beam and projection distance
Data Source
AI summary
A projector includes: a laser light source; a shaping section configured to shape a laser light emitted from the laser light source; and a scanning section configured to two-dimensionally scan, on a screen, a laser beam shaped by the shaping section. Under a situation where a distance from an optical emitting surface of the laser beam to the screen is constant, the laser light source and the shaping section are configured to perform two-dimensional scanning of the laser beam on the screen by using a tip of the laser beam corresponding to each of cross sections at a plurality of positions of a tapered portion of the laser beam from the scanning section to a beam waist of the laser beam.