Pickup Lens Positioning for Laser Projector Noise Reduction
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Solution Overview
Problem
Laser light source projectors experience wind noise due to turbulence at the edge of a rotating phosphor wheel, which is exacerbated by the placement of pickup lenses in the affected region, leading to unpleasant noise levels.
Innovation Solution
A light source apparatus design where the pickup lens is positioned such that its surface contours are inside the substrate's contour, reducing the overlap with the turbulence region, and using an inorganic phosphor layer to allow the pickup lens to be closer to the center, thereby minimizing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the pickup lens is disposed in the vicinity of the phosphor wheel to capture illumination light, then light capture efficiency is improved, but wind noise is enhanced due to turbulence in the rotating region
Solution Approach 1:
The pickup lens is extracted from the turbulence-prone region by positioning it inside the contour of the rotating substrate when viewed from the axial direction. This separates the light capture function from the noise-generating rotating region, maintaining efficiency while reducing wind noise exposure.
Solution Approach 2:
The positioning criterion transitions from radial distance alone to a two-dimensional contour relationship viewed from the axial direction. By defining the pickup lens position within the substrate's contour projection, the solution adds a dimensional perspective to resolve the contradiction between proximity for light capture and distance for noise reduction.
2Productivity
If the pickup lens is positioned closer to the substrate to improve light capture, then optical efficiency is improved, but the overlap with turbulence region increases causing more noise
Solution Approach 1:
The holding member serves as an intermediary structure that positions the pickup lens within the substrate's contour while providing structural support. This mediator enables the lens to be close to the substrate for optimal light capture without directly exposing it to the turbulence generated at the substrate's outer edges.
3Ease of manufacture
If the contour of the holding member or pickup lens extends beyond the substrate contour, then ease of assembly is improved, but noise suppression is reduced
Solution Approach 1:
The pickup lens and holding member are nested within the contour of the rotating substrate when viewed from the axial direction. This nesting arrangement ensures that all noise-sensitive components are positioned inside the substrate's boundary, preventing them from enhancing turbulence while still allowing for practical assembly through the holding member's structural design.
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 effectively reduces wind noise by minimizing the overlap of noise-enhancing objects with the turbulence region, resulting in a quieter light source apparatus and projector.
Implementation Method 1
the scattered light generator is a phosphor layer that converts light incident from the light source into fluorescence and outputs the fluorescence
Implementation Method 2
When the phosphor wheel rotates, turbulence occurs in the vicinity of the edge of the rotating substrate and the turbulence produces noise
Data Source
AI summary
A light source apparatus includes a light source, a substrate provided rotatably around a predetermined axis of rotation, a scattered light generator which is provided on the substrate and on which light from the light source is incident, a pickup lens provided on the light exiting side of the scattered light generator, and a holding member that holds the pickup lens, and at least one of the contour of a surface closest to the substrate among the surfaces of the holding member and the contour of a surface facing the substrate among the surfaces of the pickup lens is located inside the contour of the substrate when viewed in the direction parallel to the axis of rotation.