Thin Plate Lens Body for High-Efficiency LED Lighting

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Solution Overview

Problem

Conventional lighting devices with LED light sources and plate-like lens bodies face challenges in achieving efficient light utilization while maintaining a thin lens thickness, leading to reduced light-weight and efficiency due to orthogonal optical axes, which complicates lamp layout and increases lens thickness for improved light distribution.

Innovation Solution

The lighting device incorporates a plate-like lens body with multiple optical systems, including lens portions, total reflection surfaces, and air layers to redirect light radially emitted from the LED source, ensuring efficient light utilization and maintaining a thinner lens thickness by using first, second, and third optical systems to project light parallel to the optical axis from various areas of the lens body.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the lens thickness is increased to increase the area of the light incident surface, then the light utilization efficiency is improved, but the device weight increases and the compactness deteriorates

Engineering Contradiction:
Improvelight utilization efficiencyVSAvoiddevice weight
Core Design Contradiction:
Loss of energyVSWeight of moving object

Solution Approach 1:

The patent divides the light propagation path into multiple segments using several optical systems (first, second, and third optical systems) instead of relying on a single thick lens. Each optical system processes light in a specific angular range, allowing the use of thinner lens portions while maintaining overall light utilization efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a single-dimension thickness increase to a multi-dimensional optical path design. By introducing multiple optical systems that process light at different angles and positions, the solution achieves improved light utilization without increasing the thickness dimension, thereby reducing device weight.

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

2Shape

If the LED light source is disposed to face the side surface of the lens body, then a line-shaped light source is achieved, but the lamp layout becomes complicated due to orthogonal optical axes

Engineering Contradiction:
Improveline-shaped light sourceVSAvoidlamp layout complexity
Core Design Contradiction:
ShapeVSDevice complexity

Solution Approach 1:

The patent segments the light processing into multiple optical systems, each handling specific angular ranges. This segmentation allows the LED to face the side surface for line-shaped output while each optical system independently manages light from its designated angle range, simplifying the overall layout compared to a single complex optical path.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each optical system is designed with specific local properties to handle light from particular angular ranges. The first optical system handles wide-angle light, while the second and third systems handle narrow-angle light, allowing the LED to face the side surface while maintaining simple layout through localized optical processing.

Inventive Principle:
Principle #3Local quality

3Loss of energy

If multiple optical systems are introduced to redirect light efficiently, then light utilization efficiency is improved, but the device complexity increases

Engineering Contradiction:
Improvelight utilization efficiencyVSAvoidoptical system complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent divides the optical system into multiple segments (first, second, and third optical systems), each handling specific angular ranges of light. This segmentation improves light utilization by directing different light paths through appropriate optical elements, while the modular nature of segmentation keeps each individual optical system relatively simple.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a fourth optical system that can be selectively implemented to provide additional light redirection capabilities. This multi-functional approach allows the device to achieve high light utilization efficiency across different operating conditions while maintaining a base configuration that balances complexity and performance.

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 light utilization efficiency, allows for a thinner lens body, and facilitates a lightweight, line-shaped light source with uniform brightness, improving upon conventional designs by maintaining or exceeding light efficiency while reducing lens thickness and simplifying layout alignment.

Implementation Method 1

a lens portion that allows light toward the front surface and/or rear surface of the lens body to impinge thereon to gather the light near the optical axis

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

a first total reflection surface disposed on an optical path of the light entering the lens body through the first light incident surface, the first total reflection surface configured to totally reflect the light in a direction orthogonal to the optical axis

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 3

a second total reflection surface disposed on an optical path of the light totally reflected by the first total reflection surface, the second total reflection surface configured to totally reflect the light to project the light substantially parallel to the optical axis

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 4

a second light incident surface disposed in the second side surface of the lens body facing to the LED light source, the second light incident surface configured to gather, toward the optical axis, the light radially emitted from the light source in the narrow angle direction with respect to the optical axis

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 5

a third total reflection surface disposed on an optical path of the light entering the lens body by being gathered by the second light incident surface, the third total reflection surface configured to totally reflect the light sideward with respect to the optical axis

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 6

a fourth total reflection surface disposed on an optical path of the light totally reflected by the third total reflection surface, the fourth total reflection surface configured to totally reflect the light to project the light substantially parallel to the optical axis

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentEP2450725B1Lighting device
Publication Date: 2019.02.27 STANLEY ELECTRIC CO LTD
  • EP2450725B1 patent drawingFigure 1(A)~1(C)
  • EP2450725B1 patent drawingFigure 2
  • EP2450725B1 patent drawingFigure 3~4

AI summary

A lighting device (10) can utilize a lens body (30) having a thickness thinner than a conventional one and can achieve the light utilization efficiency equal to or higher than that of the conventional one. The lighting device (10) includes an LED (20) and a plate-like lens body (30) including a narrow side surface (30a) as an elongated rectangular light exiting surface (31e). The LED (20) can be disposed to face to the lens body (30) so that light emitted in a wide angle direction is directed to the front surface and the rear surface in the thickness direction and so that light in a narrow angle direction can impinge on the second side surface (30b) of the lens body (30) to enter the lens body (30). The lens body (30) can include least a first optical system (31) and a second optical system (32). The first optical system (31) can include a lens portion (31a), a first light incident surface (31b), a first total reflection surface (31c), and a second total reflection surface (31d). The second optical system (32) can include a second light incident surface (32a), a third total reflection surface (32b), and a fourth total reflection surface (32c). An air layer (S) can be provided between the lens portion (31a) and the first light incident surface (31b). This lighting device (10) can achieve the high light utilization efficiency with a low profile.