Patterned Superstrate for LED Color Point Consistency

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Solution Overview

Problem

Conventional semiconductor light emitting devices exhibit significant variation in color point as a function of viewing angle due to differing paths of emitted light through the recipient luminophoric medium, leading to inconsistent color perception across different viewing angles.

Innovation Solution

Incorporating a patterned superstrate with optical elements on the recipient luminophoric medium opposite the LED chip, which redirects and refracts light to minimize color point variation across a wide range of viewing angles, using convex protrusions, concave indentations, and varying cross-sectional shapes arranged in grids or irregular patterns to optimize light distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional semiconductor light emitting devices are used without patterned superstrates, then the device structure is simple and manufacturing is easier, but the color point variation as a function of viewing angle is significant and inconsistent

Engineering Contradiction:

Improvecolor point consistencyVSAvoiddevice structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The superstrate is segmented into multiple optical elements (convex protrusions, concave indentations, pyramids, prisms) arranged in specific patterns. Each element independently redirects light rays, collectively reducing color point variation across different viewing angles while maintaining manufacturability through standardized element designs

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the superstrate are assigned different optical element types or densities to optimize local light redirection. The patterned surface creates localized optical paths that collectively achieve uniform color point consistency across the entire device viewing angle range

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If light travels through the recipient luminophoric medium at different angles, then the device can emit light in multiple directions, but the color point varies significantly with viewing angle

Engineering Contradiction:

Improveviewing angle rangeVSAvoidcolor point consistency

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

Convex protrusions and curved optical elements are used to redirect light rays at different angles. The curved surfaces refract and reflect light to converge different angular paths toward consistent color points, maintaining color consistency while enabling wide viewing angle coverage

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The optical elements introduce additional optical paths through multiple refractions and reflections within the superstrate structure. Light rays undergo complex three-dimensional routing that equalizes the optical path lengths and angles, reducing color point variation across different viewing directions

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Manufacturing precision

If a patterned superstrate with optical elements is added, then color point variation is reduced to within 0.01, but the device structure becomes more complex

Engineering Contradiction:

Improvecolor point consistencyVSAvoidsuperstrate structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

Standardized optical element designs (convex protrusions, concave indentations, pyramids, prisms) are repeatedly copied and arranged in patterns across the superstrate. This modular approach achieves precise color point consistency while simplifying manufacturing through replication of proven element designs

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The optical elements are designed with specific geometric parameters (height, width, angles, curvature radii) that are optimized to reduce color point variation. By controlling these physical parameters within tight tolerances, the device achieves color point consistency within 0.01 while maintaining manageable structural complexity

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

The patterned superstrate significantly reduces color point variation in both ccx and ccy coordinates to within 0.01 for viewing angles up to 40 degrees, maintaining color consistency and improving light sharpness and contrast without degrading intensity.

Implementation Method 1

the patterned superstrate with optical elements on the recipient luminophoric medium opposite the LED chip, which redirects and refracts light to minimize color point variation across a wide range of viewing angles

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS11309462B2Semiconductor light emitting devices including superstrates with patterned surfaces

Publication Date: 2022.04.19 CREELED INC

AI summary

A semiconductor light emitting device includes a light emitting diode (LED) chip, a recipient luminophoric medium on the LED chip, a patterned superstrate on the recipient luminophoric medium opposite the LED chip, the patterned superstrate comprising a patterned superstrate on the recipient luminophoric medium opposite the LED chip, the patterned superstrate comprising a patterned surface that is configured to reduce a variation in a color point of a light emitted by the semiconductor light emitting device as a function of an angle off an optical axis of the LED chip.