Lambertian Backlight Module Layout for Thin Uniform Displays
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Solution Overview
Problem
Existing backlight modules for large-size and ultra-thin display devices face challenges in achieving thinness due to the need for sufficient optical paths to uniformize point light sources, resulting in increased thickness.
Innovation Solution
A backlight module design incorporating a light-emitting substrate with a transparent substrate, encapsulation layer, and a first reflective layer that is a Lambertian body, which reduces thickness by utilizing the optical path within the encapsulation and transparent substrate, and includes a polarizing layer and diffusion layer to enhance uniformity and brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If traditional backlight modules use extended optical paths with separate diffusion plates and air gaps to uniformize point light sources, then light uniformity is improved, but the overall thickness of the backlight module increases
Solution Approach 1:
The patent merges the diffusion plate and air gap functions into the encapsulation layer itself. The encapsulation layer is designed with specific optical properties (diffusion coefficient, thickness) to perform both the diffusion function traditionally requiring a separate plate and the optical path extension function traditionally requiring an air gap, thereby reducing overall module thickness while maintaining light uniformity
Solution Approach 2:
The encapsulation layer is designed to perform multiple functions simultaneously: it serves as both the diffusion element and the optical path medium, replacing what were traditionally separate components (diffusion plate and air gap). This multi-functionality reduces the number of layers needed and decreases overall module thickness
2Illumination intensity
If the encapsulation layer thickness is increased to provide sufficient optical path for light diffusion, then light uniformity is improved, but the overall thickness of the backlight module increases
Solution Approach 1:
The patent optimizes specific parameters of the encapsulation layer including its thickness (first thickness parameter), diffusion coefficient (second parameter), and refractive index. By carefully selecting these parameters, the encapsulation layer achieves sufficient optical path length for effective diffusion without requiring excessive physical thickness, thus resolving the contradiction between uniformity and thinness
3Length of stationary object
If the light-emitting units are arranged closer together to reduce module thickness, then backlight module thickness is reduced, but light uniformity deteriorates
Solution Approach 1:
The patent applies local quality by designing the encapsulation layer with position-dependent optical properties. The diffusion coefficient and thickness may vary across different regions to compensate for the closer spacing of light-emitting units, ensuring that each region contributes appropriately to overall light uniformity despite reduced inter-unit distance
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 design achieves a thinner backlight module by optimizing optical path utilization and reducing thickness, while maintaining brightness and uniformity, suitable for high-end display devices with high color gamut and purity.
Implementation Method 1
the first reflective layer is a Lambertian body
Implementation Method 2
The encapsulation layer is disposed on a side of the plurality of light-emitting units away from the transparent substrate
Implementation Method 3
optimizing optical path utilization
Data Source
AI summary
A backlight module, including a light-emitting unit, emergent light of which passes through a packaging layer and then is transmitted to a surface of a first reflective layer, then passes through the surface of the first reflective layer and passes through the packaging layer again, enters a light-transmitting substrate from the packaging layer, and is emitted from the side of the light-transmitting substrate distant from the light-emitting unit. The thicknesses of the packaging layer and the light-transmitting substrate are effectively utilized to increase an optical path, thereby reducing the thickness of the backlight module. The first reflective layer is Lambertian. The side of the first reflective layer near the light-transmitting substrate and the side distant from the light-transmitting substrate allow the emergent light transmitted to the surface thereof to be scattered and homogenized to increase the optical path again, and can also function as diffusor plates.