Donut-Shaped Diffusion Plate With Flat Rims to Limit Glass Stress

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Solution Overview

Problem

Existing diffusion plates with a donut-shaped glass substrate and lens array are prone to excessive stress concentration at the inner and outer circumferences, leading to potential breakage due to the presence of lenses.

Innovation Solution

Incorporating annular flat surfaces with a width of at least 1.0 mm along the inner and/or outer peripheries of the glass substrate, and using laser processing to form the lens array, followed by wet etching to enhance the structural integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a lens array is formed over the entire surface of a donut-shaped glass substrate, then light distribution controllability is improved, but excessive stress concentration occurs on the inner and outer circumferences causing the glass substrate to break

Engineering Contradiction:

Improvelight distribution controllabilityVSAvoidglass substrate strength

Core Design Contradiction:

Illumination intensityVSStrength

Solution Approach 1:

The glass substrate surface is segmented into three distinct regions: a first flat surface at the inner circumference, a lens array region in the middle, and a second flat surface at the outer circumference. This segmentation allows the lens array to be present only in specific areas where it is needed for light distribution, while the flat surface regions provide stress relief zones that prevent breakage.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the glass substrate are given different local properties: the flat surface regions have smooth, lens-free surfaces optimized for stress distribution, while the lens array region has micro-structured surfaces optimized for light distribution control. This local differentiation allows each region to perform its specific function without compromising the overall structure.

Inventive Principle:

Principle #3Local quality

2Ease of manufacture

If sandblasting is used to process the glass substrate, then manufacturing simplicity is maintained, but light distribution controllability is insufficient compared to lens array formation

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidlight distribution controllability

Core Design Contradiction:

Ease of manufactureVSIllumination intensity

Solution Approach 1:

Instead of applying lens structures to the entire glass substrate surface, the lens array is applied only to the necessary intermediate region between the inner and outer flat surfaces. This partial application achieves the required light distribution control while avoiding the stress concentration that would result from full-surface lens formation.

Inventive Principle:

Principle #16Partial or excessive action

3Adaptability or versatility

If the glass substrate has a donut shape with a through hole, then structural design flexibility is improved, but stress concentration at the inner and outer circumferences increases

Engineering Contradiction:

Improvestructural design flexibilityVSAvoidstress concentration

Core Design Contradiction:

Adaptability or versatilityVSStress or pressure

Solution Approach 1:

The donut-shaped glass substrate surface is divided into distinct functional zones: inner flat surface, lens array region, and outer flat surface. The flat surface regions act as stress distribution zones that mitigate the inherent stress concentration at the inner and outer circumferences of the donut shape, while still maintaining the structural flexibility provided by the through-hole design.

Inventive Principle:

Principle #1Segmentation

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

The annular flat surfaces effectively suppress excessive stress concentration, improving the strength and durability of the diffusion plate, reducing the risk of cracks and breakage.

Implementation Method 1

using laser processing to form the lens array

Methodology Applied

Scientific EffectLaser: Laser

Implementation Method 2

followed by wet etching to enhance the structural integrity

Methodology Applied

Scientific EffectWet etching:

Data Source

PatentUS20260009933A1Diffusion plate, method of manufacturing diffusion plate, and projection device

Publication Date: 2026.01.08 AGC INC

AI summary

A diffusion plate includes: a glass substrate having a first main surface and a second main surface opposite to the first main surface; and a lens array formed on the first main surface of the glass substrate, wherein, when the first main surface of the glass substrate is viewed in a plan view, the glass substrate and the lens array each have a donut shape, the lens array includes a plurality of lenses, and the first main surface of the glass substrate has an annular first flat surface having a width equal to or more than 1.0 mm between an inner periphery of the glass substrate and an inner periphery of the lens array, or has an annular second flat surface having a width equal to or more than 1.0 mm between an outer periphery of the glass substrate and an outer periphery of the lens array.