Microlens Array Alignment via Photolithography and Dry Film Resist

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Solution Overview

Problem

Existing methods for manufacturing microlens arrays on light emitting element arrays face challenges in accurately aligning the light emitting elements with the lens array, leading to increased manufacturing steps and complexity, particularly due to the need for spacers and alignment difficulties with stamper-based techniques.

Innovation Solution

A method involving the formation of lens pillars on a light emitting element array using photolithography, followed by laminating a dry film resist to create a microlens array that focuses light emitted by the elements, eliminating the need for a mold and spacer, and allowing for accurate alignment and simple manufacturing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a stamper-based method with spacers is used to form microlens arrays, then microlenses can be formed on light emitting elements, but accurate alignment between the wafer and stamper becomes difficult and the number of manufacturing steps increases

Engineering Contradiction:
Improvealignment accuracy between wafer and stamperVSAvoidnumber of manufacturing steps
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates the stamper and spacer components from the manufacturing process. Instead of using a separate stamper with spacers to form microlenses, the method directly forms lens pillars on the light emitting elements themselves through photolithography, thereby removing the alignment problems and additional steps associated with stamper-based methods

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention merges the light emitting element formation process with the microlens formation process. By forming lens pillars directly on the light emitting elements in the same manufacturing sequence, the method combines two previously separate processes (forming light emitting elements and forming microlenses) into one integrated process, eliminating the need for separate stamper alignment and spacer installation steps

Inventive Principle:
Principle #5Merging (Combining)

2Shape

If UV-curable resin is filled in concaves of a stamper with spacers to form microlenses, then microlens structure can be created, but the manufacturing process becomes complex and alignment accuracy deteriorates

Engineering Contradiction:
Improvemicrolens structureVSAvoidmanufacturing process complexity
Core Design Contradiction:
ShapeVSDevice complexity

Solution Approach 1:

The invention replaces the mechanical stamper-based molding system with a photolithographic system. Instead of mechanically filling UV-curable resin into stamper concaves and using spacers to define thickness, the method uses light exposure through a photomask to directly pattern lens pillars with precise shapes, eliminating the mechanical complexity of stamper fabrication and alignment

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the formation mechanism from mechanical molding (stamper compression) to photonic patterning (light exposure). By changing the fundamental parameter of how the microlens shape is defined—from mechanical contact and resin flow to photolithographic exposure and development—the process achieves both structural precision and manufacturing simplicity

Inventive Principle:
Principle #35Parameter changes

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 accurate alignment and formation of a microlens array without specialized equipment, reducing manufacturing complexity and allowing for adjustable microlens curvatures and thickness, enhancing light-use efficiency in display applications.

Implementation Method 1

forming a plurality of lens pillars on the light emitting elements by performing a photolithographic process on said photoresist layer

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Implementation Method 2

forming a lens portion by performing heat treatment to cause the dry film resist to be softened so that softened dry film resist fills the gaps

Methodology Applied
Scientific EffectHeat treatment: Heat Treatment

Data Source

PatentEP2328176B1Manufacturing method of a display panel
Publication Date: 2015.02.25 OKI DATA CORP
  • EP2328176B1 patent drawingFigure 1~2
  • EP2328176B1 patent drawingFigure 3
  • EP2328176B1 patent drawingFigure 4

AI summary

A display panel includes a substrate and a light emitting element array including a plurality of light emitting elements provided on the substrate. The light emitting elements are driven by driving signals to emit flight. The display panel further includes a lens array that focuses the light emitted by the light emitting elements, and a driving circuit provided on the substrate for driving the light emitting elements. The lens array includes a plurality of lens pillars formed on the light emitting elements, and a plurality of lens portions formed to cover the lens pillars and to have curved lens surfaces. Selected Figure: FIG. 7F