Ring Flash Light Guide With Vertical LED Sides

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Solution Overview

Problem

Conventional ring flashes using individual LEDs for camera phones often produce non-uniform illumination due to hot spots, especially when small or operating continuously, which can create shadows in macrophotography and reduce image quality.

Innovation Solution

A ring-shaped light guide module incorporating LEDs with vertical light-emitting sides and a light guide featuring a circular body with in-coupling surfaces for total internal reflection, combined with a reflector and diffuser films to achieve uniform illumination, and optionally multiple LEDs for color creation or animated effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If conventional ring flashes use individual LEDs for camera phones, then the device size is reduced, but the illumination uniformity deteriorates due to hot spots

Engineering Contradiction:
Improvedevice sizeVSAvoidillumination uniformity
Core Design Contradiction:
Volume of moving objectVSIllumination intensity

Solution Approach 1:

The patent segments the light emission function by using an LED with multiple vertical light-emitting sides rather than a single-point LED. This segmentation distributes the light sources around the optical axis, reducing hot spots and improving illumination uniformity while maintaining a compact ring flash structure suitable for camera phones.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from conventional single-direction or two-direction LED emission to multi-directional emission by incorporating vertical light-emitting sides on the LED. This dimensional change in light emission directionality enables more uniform illumination distribution around the lens while keeping the device compact.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Device complexity

If conventional ring flashes use individual LEDs, then the structural complexity is reduced, but shadow formation increases in macrophotography

Engineering Contradiction:
Improvestructural complexityVSAvoidshadow formation
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the light source into multiple vertical emitting sides on a single LED structure. This segmentation positions light sources at multiple locations around the optical axis, eliminating shadows in macrophotography while maintaining relatively simple device structure and avoiding the need for multiple separate LED components.

Inventive Principle:
Principle #1Segmentation

3Productivity

If ring flashes operate continuously, then the productivity is improved, but the illumination uniformity deteriorates due to hot spots

Engineering Contradiction:
Improvecontinuous operation capabilityVSAvoidillumination uniformity
Core Design Contradiction:
ProductivityVSIllumination intensity

Solution Approach 1:

The patent uses an LED with multiple vertical light-emitting sides that segments the light emission across different spatial locations. This segmentation prevents hot spot formation during continuous operation, maintaining illumination uniformity even when the ring flash operates continuously for video recording or flashlight mode.

Inventive Principle:
Principle #1Segmentation

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 uniform and vectored light emission, reducing shadows and enhancing image quality by minimizing hot spots and ensuring consistent illumination around the camera lens.

Implementation Method 1

an outer sidewall defining an opening or indentation having two vertical in-coupling surfaces, which are mated to respective light-emitting sides of the LED

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentEP3405837B1Uniform, efficient, and color tunable ring flash for camera using leds with light emission from multiple sides
Publication Date: 2021.12.08 LUMILEDS LLC
  • EP3405837B1 patent drawingFigure 1~2
  • EP3405837B1 patent drawingFigure 3~4
  • EP3405837B1 patent drawingFigure 5

AI summary

A device includes a light-emitting device (LED) having at least two vertical light- emitting sides, and a ring-shaped light guide having a bottom side, a top side comprising a light-emitting surface, an inner sidewall, and an outer sidewall defining an indentation having at least two vertical in-coupling surfaces mated to the at least two vertical light-emitting sides of the LED.