Light Guide Prism Array Thin Lighting Design
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Solution Overview
Problem
Conventional lighting devices with small light distribution angles require a certain depth to achieve parallel light, making it difficult to create a thin and compact design, and they often need to be replaced to change the color temperature of the emitted light.
Innovation Solution
A lighting device comprising a light guide, a reflecting sheet, and prism sheets with LEDs of different color temperatures disposed uniformly on the side surfaces, along with prism arrays on the light guide and sheets to control light distribution, allowing for a thin design and easy color temperature adjustment by switching between LEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a parabolic mirror is used to form parallel light for small light distribution angle, then the light distribution angle is reduced, but the device depth increases making it difficult to achieve a thin design
Solution Approach 1:
The patent replaces the mechanical parabolic mirror system with an optical system consisting of a light guide plate and prism arrays. The light guide plate transfers light from LEDs positioned on its side surface to its main surface, while the prism arrays (first on the light guide, second on the emitting surface) control light extraction and direction. This substitution eliminates the need for deep mechanical structures, achieving a thin device profile while maintaining small light distribution angle through optical path control rather than mechanical geometry.
Solution Approach 2:
The patent positions LEDs on the side surface of the light guide plate rather than at the front or back, utilizing the lateral dimension for light source placement. The light then propagates through the light guide plate and is extracted through the main surface, effectively using the thickness dimension of the light guide plate to achieve the optical function that would otherwise require significant depth in the optical axis direction. This dimensional reconfiguration enables thin device design.
2Adaptability or versatility
If white LEDs of different color temperatures are used to change color temperature, then color temperature adjustment is achieved, but the light source itself must be replaced which increases device complexity
Solution Approach 1:
The patent incorporates a liquid crystal lens that can dynamically change its focal length or optical properties in response to electrical signals. This allows the lighting device to adjust its optical characteristics, including color temperature mixing and light distribution patterns, without any physical replacement of components. The liquid crystal lens provides dynamic adaptability by changing its refractive index or lens power electronically, enabling versatile color temperature adjustment while maintaining a fixed, simple device structure.
Solution Approach 2:
The liquid crystal lens serves multiple functions: it controls light focusing, adjusts color temperature by varying the mixing ratio of lights from different LEDs, and can potentially control light distribution angle. This single component performs what would otherwise require multiple separate optical elements or mechanical adjustment mechanisms, reducing device complexity while enhancing adaptability.
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 a thin lighting device with a small light distribution angle and the ability to easily change the color temperature of the emitted light, providing a compact and versatile lighting solution.
Implementation Method 1
a light guide (13), a reflecting sheet (12) disposed under the light guide (13), and a first prism sheet (15) disposed over the light guide (13)
Implementation Method 2
a first prism array extending in a orthogonal direction to the first side surface and arranged in a parallel direction with the first side surface is formed on a major surface of the light guide
Data Source
AI summary
A lighting device including: a light guide, a reflecting sheet and a first prism sheet, in which a first white LED, a second white LED and a third white LED are disposed in a same interval on a first side surface and on a second side surface, which opposes to the first side surface, a first prism array extending in a first direction and arranged in a second direction is formed on the major surface, a second prism array extending in a second direction and arranged in a first direction is formed on the back surface, the reflecting sheet is disposed under the back surface of the light guide, the first prism sheet is disposed on the major surface of the light guide, and a third prism array, extending in the second direction and arranged in the first direction is formed on the back surface of the first prism sheet.