Eyewear Projector Brightness Control With Variable Feedback Loop

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Solution Overview

Problem

Existing augmented reality and virtual reality eyewear systems lack effective brightness control mechanisms that adapt to varying ambient light conditions, leading to discomfort and reduced image visibility.

Innovation Solution

The eyewear incorporates a variable feedback loop that controls the forward current to a colored light source, allowing it to switch between high brightness in outdoor settings and nominal brightness indoors, enhancing image visibility in different lighting conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the projector operates at high brightness, then image visibility in outdoor settings is improved, but energy consumption increases and the device may overheat

Engineering Contradiction:
Improveimage brightnessVSAvoidenergy consumption
Core Design Contradiction:
Illumination intensityVSUse of energy by moving object

Solution Approach 1:

The patent implements dynamic brightness adjustment by switching between high brightness mode for outdoor use and normal brightness mode for indoor use. The controller dynamically adjusts the forward current to the light source based on ambient light conditions, enabling the projector to adapt its illumination intensity rather than operating at a fixed high brightness level.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the operating parameters of the light source by adjusting the forward current through different feedback resistance values. The controller selectively establishes different feedback loop configurations (with different resistance values) to control the light source at different brightness levels, thereby changing the electrical and optical parameters to match environmental conditions.

Inventive Principle:
Principle #35Parameter changes

2Illumination intensity

If the projector operates at high brightness, then image visibility in outdoor settings is improved, but device temperature increases

Engineering Contradiction:
Improveimage brightnessVSAvoiddevice temperature
Core Design Contradiction:
Illumination intensityVSTemperature

Solution Approach 1:

The system dynamically adjusts brightness based on ambient light detection, operating at high brightness only when outdoors and switching to normal brightness indoors. This dynamic operation reduces the cumulative thermal load on the device while maintaining image visibility when needed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The controller changes the electrical parameters (forward current) and optical parameters (brightness) of the light source based on environmental conditions, thereby controlling the thermal output to match operational requirements rather than continuously operating at maximum power.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If a simple brightness control mechanism is used, then device complexity is reduced, but adaptability to varying ambient light conditions deteriorates

Engineering Contradiction:
Improvecontrol mechanism complexityVSAvoidadaptability to ambient light
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent employs feedback control mechanisms where the controller detects ambient light conditions and adjusts the light source brightness accordingly. The feedback loop uses resistance values to control the forward current, creating a closed-loop system that automatically adapts to varying ambient light conditions without requiring complex manual intervention.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs self-adjustment of brightness based on ambient light detection. The controller automatically determines whether the device is being worn indoors or outdoors and adjusts the light source parameters accordingly, enabling the device to serve itself rather than requiring external control for each brightness adjustment.

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 provides adaptive brightness control, ensuring clear image display in both indoor and outdoor environments, improving user experience and comfort.

Implementation Method 1

a colored light source configured to generate a colored light beam to generate a displayed image

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 2

The variable feedback loop in one example has a variable resistance to selectively generate a high brightness image

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Data Source

PatentEP4314934B1Eyewear projector brightness control
Publication Date: 2025.10.15 SNAP INC
  • EP4314934B1 patent drawingFigure 1A
  • EP4314934B1 patent drawingFigure 1B
  • EP4314934B1 patent drawingFigure 2A

AI summary

Eyewear including a projector having a variable feedback loop controlling a forward current delivered to a colored light source. The colored light source is configured to generate a colored light beam to generate a displayed image. The variable feedback loop in one example has a variable resistance to selectively generate a high brightness image when the eyewear is operated outside, or in a high ambient light setting, and to selectively generate a nominal brightness image when the eyewear is operated inside. A controller selectively controls the drive current delivered to the colored light source to control the brightness mode of the image.