Light-emitting Device with Parallel LED Units for Color Temperature Control

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Solution Overview

Problem

Existing light-emitting devices face complexity in wiring patterns and power loss due to resistors, leading to inefficient power supply and variable color temperature control when using multiple power sources or resistors.

Innovation Solution

A light-emitting device design featuring multiple light-emitting units connected in series, each with a different number of blue LED chips and phosphors, allowing for adjustable color temperature through a single power source by varying the current, eliminating the need for resistors and simplifying the wiring pattern.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple power sources are used to control color temperature, then color temperature adjustment capability is improved, but device complexity increases due to multiple wiring patterns

Engineering Contradiction:
Improvecolor temperature adjustment capabilityVSAvoidwiring pattern complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent divides the light-emitting device into multiple independent light-emitting units, each with its own light-emitting element and phosphor layer. This segmentation allows each unit to be controlled independently through current adjustment, enabling color temperature control without requiring multiple power sources or complex wiring patterns.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent controls the output of each light-emitting unit by changing the current parameter supplied to each unit. By adjusting the current ratios to different light-emitting units with different color characteristics, the overall color temperature of the device can be adjusted continuously without changing the wiring structure or power source configuration.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If resistors are used to control current distribution, then current ratio adjustment is improved, but energy efficiency deteriorates due to power loss at resistors

Engineering Contradiction:
Improvecurrent ratio adjustmentVSAvoidpower loss at resistor
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The patent removes resistors from the circuit by directly controlling the current supplied to each light-emitting unit through the power source. This extraction of the resistor component eliminates the power loss that would occur at resistive elements while maintaining the ability to adjust current distribution to different light-emitting units.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The light-emitting units themselves serve the function of current regulation through their inherent electrical characteristics. By selecting light-emitting units with different forward voltage characteristics and controlling their current independently, the system achieves current ratio adjustment without requiring external resistive elements, making the light-emitting units self-regulating in terms of current distribution.

Inventive Principle:
Principle #25Self-service

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 solution enables efficient power usage, reduces power loss, and allows for adjustable color temperature within a wide range (2700 K to 6500 K) by varying the current, improving luminous efficiency and simplifying the device structure.

Implementation Method 1

each comprising blue light-emitting LED chips, phosphors, and a light-transmitting resin

Methodology Applied
Scientific EffectPhosphorescence: Phosphorescence

Implementation Method 2

blue light-emitting LED chips

Methodology Applied
Scientific EffectLight emission from LED: Light Emitting Diode

Implementation Method 3

first light-emitting unit and second light-emitting units electrically connected in parallel to be supplied with current from a single power source

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP3279939B1Light-emitting device
Publication Date: 2019.12.18 SHARP KK
  • EP3279939B1 patent drawingFigure 1
  • EP3279939B1 patent drawingFigure 2~3
  • EP3279939B1 patent drawingFigure 4~5

AI summary

There is provided a light-emitting device including an anode electrode land, a cathode electrode land, and a first light-emitting unit and a second light-emitting unit electrically connected to the anode electrode land and the cathode electrode land and provided in parallel to each other, in which the first light-emitting unit and the second light-emitting unit each include blue light-emitting LED chips, the first light-emitting unit and the second light-emitting unit have different amounts of change in luminous flux with respect to an amount of change in current applied between the anode electrode land and the cathode electrode land, and a color temperature generated from an entire light-emitting unit including the first light-emitting unit and the second light-emitting unit can be adjusted.