Chip-Scale White LED Units with Wavelength Conversion for Uniform Full-Color Displays

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Solution Overview

Problem

Light-emitting diode displays face issues with uneven illumination, electrical controlling difficulties, and high manufacturing costs due to their design and construction.

Innovation Solution

The display device incorporates chip-scale packaged white light-emitting units with a wavelength conversion film covering the light-emitting diode chips, which emit blue light converted to white, and a color filter layer to produce various colors, reducing overall thickness and material usage, and addressing electrical controlling challenges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traditional red, green, and blue light-emitting diode chips are used to form pixels, then full-color display is achieved, but uneven illumination and electrical controlling difficulties occur

Engineering Contradiction:

Improvefull-color display capabilityVSAvoidillumination uniformity and electrical control

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The invention divides the display into independently controllable white light-emitting units, each capable of emitting white light through wavelength conversion. These units are then selectively activated using color filters to produce full-color display, eliminating the illumination uniformity and control issues of traditional RGB LED approaches

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention introduces wavelength conversion films as intermediaries that convert blue light from LEDs into white light. This intermediary mechanism enables uniform white light emission from each unit, which can then be selectively filtered to achieve full-color display without the problems of direct RGB LED control

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If conventional light-emitting diode display structure is used, then full-color display is achieved, but device size cannot be reduced

Engineering Contradiction:

Improvefull-color display capabilityVSAvoiddevice size

Core Design Contradiction:

Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The invention merges the light-emitting function and color generation function into a single integrated unit structure. Each white light-emitting unit combines the LED chip, wavelength conversion film, and color filter, eliminating the need for separate RGB chip assemblies and reducing overall device size while maintaining full-color display capability

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The invention transitions from a planar arrangement of separate RGB chips to a vertically stacked integrated unit structure. The wavelength conversion film and color filter are positioned above the LED chip in the vertical dimension, enabling compact three-dimensional integration that reduces device footprint while achieving full-color display

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Adaptability or versatility

If traditional light-emitting diode display construction is used, then full-color display is achieved, but manufacturing cost increases

Engineering Contradiction:

Improvefull-color display capabilityVSAvoidmanufacturing cost

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The invention uses a universal white light-emitting unit design where a single LED chip type (blue LED) combined with wavelength conversion films can produce all colors. This universal approach eliminates the need to manufacture and inventory multiple types of colored LED chips, simplifying the supply chain and reducing manufacturing costs while maintaining full-color display capability

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 enhances illumination uniformity, simplifies electrical control, and lowers production costs by reducing material usage and overall device thickness.

Implementation Method 1

the wavelength conversion film converts light emitted by the light-emitting diode chip into white light

Methodology Applied

Scientific EffectWavelength conversion: Fluorescence

Implementation Method 2

the color filter layer includes a plurality of color resists, each of the color resists is a red color resist, a green color resist or a blue color resist, and the color resists respectively correspond to the white light-emitting units

Methodology Applied

Scientific EffectOptical filtering: Filter (optical)

Data Source

PatentUS11469352B2Display device and manufacturing method thereof

Publication Date: 2022.10.11 ENNOSTAR CORP

AI summary

A display device includes a substrate, a plurality of white light-emitting units, and a color filter layer. The white light-emitting units are arranged on the substrate at intervals, and the white light-emitting units are chip scale package (CSP). The color filter layer is above the white light-emitting units. Each of the white light-emitting units includes a light-emitting diode chip and a wavelength conversion film. The wavelength conversion film directly covers a top surface and side surfaces of the light-emitting diode chip, and the wavelength conversion film converts light emitted by the light-emitting diode chip into white light.