Dual LED Drive Circuit for Active Stylus

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Solution Overview

Problem

The existing active stylus designs with multiple electrical connectors increase cost, complexity, and size, while also reducing reliability due to the higher number of potential failure points.

Innovation Solution

A drive circuit configuration that connects two LEDs to a single electrical connector, allowing either LED to be activated by positive or negative voltage, reducing the number of connectors and enhancing reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple electrical connectors are used to connect multiple LEDs, then each LED can be independently controlled, but the cost, complexity, and size increase while reliability decreases

Engineering Contradiction:
ImprovereliabilityVSAvoidcomplexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple electrical connectors into a single shared electrical connector that serves multiple LEDs. The drive circuit is configured to selectively connect this single connector to different LEDs through switching elements, eliminating the need for separate dedicated connectors for each LED. This reduces the number of connectors while maintaining independent control capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single electrical connector is designed to serve multiple functions by being selectively connected to different LEDs through the drive circuit. The connector acts as a universal interface that can drive any of the multiple LEDs depending on the operational state, replacing what would traditionally require multiple dedicated connectors.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If multiple electrical connectors are used to connect multiple LEDs, then each LED can be independently controlled, but the cost, complexity, and size increase while reliability decreases

Engineering Contradiction:
ImprovereliabilityVSAvoidcost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges multiple electrical connectors into a single shared electrical connector that serves multiple LEDs. The drive circuit is configured to selectively connect this single connector to different LEDs through switching elements, eliminating the need for separate dedicated connectors for each LED. This reduces the number of connectors while maintaining independent control capability.

Inventive Principle:
Principle #5Merging (Combining)

3Device complexity

If multiple electrical connectors are used to connect multiple LEDs, then each LED can be independently controlled, but the number of connectors increases device size

Engineering Contradiction:
ImprovecomplexityVSAvoidsize
Core Design Contradiction:
Device complexityVSVolume of moving object

Solution Approach 1:

The patent merges multiple electrical connectors into a single shared electrical connector that serves multiple LEDs. The drive circuit is configured to selectively connect this single connector to different LEDs through switching elements, eliminating the need for separate dedicated connectors for each LED. This reduces the number of connectors while maintaining independent control capability.

Inventive Principle:
Principle #5Merging (Combining)

4Device complexity

If multiple electrical connectors are used to connect multiple LEDs, then each LED can be independently controlled, but the number of potential failure points increases

Engineering Contradiction:
ImprovecomplexityVSAvoidreliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent merges multiple electrical connectors into a single shared electrical connector that serves multiple LEDs. The drive circuit is configured to selectively connect this single connector to different LEDs through switching elements, eliminating the need for separate dedicated connectors for each LED. This reduces the number of connectors while maintaining independent control capability.

Inventive Principle:
Principle #5Merging (Combining)

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 solution reduces the cost, size, and complexity of the active stylus while increasing its reliability by minimizing the number of electrical connectors and potential failure points.

Implementation Method 1

A first LED is electrically intermediate the second node and ground, and a second LED is electrically intermediate the second node and ground. The first LED is configured to activate based on the negative voltage generator supplying a negative voltage to the second node via the first node. The second LED is configured to activate based on the positive voltage generator supplying a positive voltage to the second node via the first node.

Methodology Applied
Scientific EffectLight emitting diode (LED): Light Emitting Diode

Data Source

PatentEP3603343B1Dual LED drive circuit
Publication Date: 2021.03.10 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP3603343B1 patent drawingFigure 1~2
  • EP3603343B1 patent drawingFigure 3
  • EP3603343B1 patent drawingFigure 4

AI summary

A circuit, includes a first node, a positive voltage generator electrically connected to the first node, a negative voltage generator electrically connected to the first node in parallel with the positive voltage generator, a second node, an electrical connector electrically connecting the first node to the second node, a first light emitting diode (LED) electrically intermediate the second node and ground, and a second LED electrically intermediate the second node and ground in parallel with the first LED. The first LED is configured to activate based on the negative voltage generator supplying a negative voltage to the second node via the first node. The second LED is configured to activate based on the positive voltage generator supplying a positive voltage to the second node via the first node.