Acoustically Transmissive Front Projection Screen Microperforations
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Solution Overview
Problem
Conventional front projection screens face challenges in maintaining adequate acoustic transmission while minimizing optical loss and visual artifacts, particularly in cinema environments where speakers are positioned behind the screen, requiring precise perforation and seaming processes that are difficult to execute without disrupting the screen's uniformity and brightness.
Innovation Solution
The development of acoustically transmissive front projection screens featuring microperforations less than 300 microns in diameter with a conical shape, achieved through laser slitting and perforation, allowing for a high optical fill factor of 1%-3% and seamless joining of substrate sections without machine direction alignment, which reduces acoustic attenuation and visual imperfections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional perforations are used to achieve acoustic transmission, then acoustic transmission is improved, but optical loss and visual artifacts increase
Solution Approach 1:
The patent changes the scale parameter of perforations from conventional sizes to microperforations (50-300 microns), and changes the shape parameter to conical cross-sections. These parameter changes enable sufficient acoustic transmission while minimizing optical loss and maintaining visual homogeneity, as the small size and specific geometry reduce the visual impact and light scattering effects.
Solution Approach 2:
The patent applies different geometrical properties to different parts of the perforation structure - conical shape with specific aperture sizes at the front surface versus the overall hole geometry. This local quality differentiation optimizes acoustic transmission through the conical shape while minimizing visual artifacts from the front-surface aperture characteristics.
2Ease of manufacture
If seams are joined without machine direction alignment to reduce manufacturing complexity, then ease of manufacture is improved, but visual uniformity deteriorates
Solution Approach 1:
The patent changes the pitch parameter of the perforation pattern from uniform to non-uniform (increasing pitch from center to edge). This parameter change creates visual compensation that masks seam locations, allowing seams to be joined without precise machine direction alignment while maintaining visual uniformity across the screen surface.
Solution Approach 2:
The patent introduces asymmetry in the pitch distribution of perforations - with pitch gradually increasing from the center toward the edges of the screen. This asymmetric pattern creates visual gradients that distract from and mask seam locations, enabling easier manufacturing without compromising visual uniformity.
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 approach enables high acoustic transmission with minimal optical loss and visually imperceptible seams, enhancing the audio-visual experience by maintaining a homogeneous appearance and reducing manufacturing complexities related to registration and alignment.
Implementation Method 1
The microperforations may allow the first and second portions of material to maintain an approximate predetermined acoustical transmission range
Implementation Method 2
The undercut edge profile may be achieved with laser slitting
Data Source
Figure 1A~1B
Figure 1C
Figure 2
AI summary
A front projection screen is provided having a first portion of material and a second portion of material. The first and second portions of material may have an undercut edge profile, and the first and second portions of material may be perforated, such that the perforations allow the first and second portions of material to be at least somewhat acoustically transmissive while substantially maintaining optical efficiency from the front side of the front projection screen. Such optical efficiency has particular utility in stereoscopic projection applications utilizing polarized encoded light.