Transparent Display Panel Refraction Layers for Light Extraction
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Solution Overview
Problem
Transparent display panels suffer from low brightness or high power consumption due to total internal reflection at the interface between the cover plate and air, leading to reduced emergent light efficiency.
Innovation Solution
A display panel design incorporating a low refraction layer and a high refraction layer to form a total reflection interface, deflecting display light at oblique angles towards a forward viewing angle, thereby reducing total internal reflection and improving emergent light efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a transparent display panel uses a conventional single-layer structure, then the device complexity is low, but the emergent light efficiency is reduced due to total internal reflection at the cover plate-air interface
Solution Approach 1:
The patent divides the optical interface into multiple segments: a cover plate layer, a low refraction layer, and a high refraction layer. Each layer serves a specific optical function, with the low refraction layer (refractive index 1.3-1.6) and high refraction layer (refractive index 1.7-1.9) creating distinct interfaces that control light propagation separately, thereby reducing total internal reflection losses while maintaining manageable structural complexity
Solution Approach 2:
The low refraction layer acts as an intermediary between the cover plate and the high refraction layer. This intermediate layer with refractive index 1.3-1.6 creates a gradual transition for light passing from the cover plate through to the display area, reducing abrupt refraction and total internal reflection at interfaces, thus improving emergent light efficiency without requiring a complex multi-component system
2Illumination intensity
If the display panel increases display brightness, then the illumination intensity improves, but the power consumption increases
Solution Approach 1:
The patent converts the harmful effect of total internal reflection at the cover plate-air interface into a beneficial light guiding mechanism. By designing the low refraction layer and high refraction layer with specific refractive indices, oblique incident light is redirected through total internal reflection at the high refraction layer interface toward the front viewing area, transforming what would be lost light into useful display brightness without requiring additional power
Solution Approach 2:
The patent optimizes the refractive index parameters of the low refraction layer (1.3-1.6) and high refraction layer (1.7-1.9) to maximize light extraction efficiency. By carefully selecting these optical parameters, the system achieves higher display brightness through improved light propagation and reduced internal reflection losses, thereby reducing the power needed to achieve a given brightness level
3Illumination intensity
If the display panel optimizes for front viewing angle, then the display brightness at front side improves, but the display uniformity across different viewing angles deteriorates
Solution Approach 1:
The patent applies different optical properties to different regions and layers: the low refraction layer (refractive index 1.3-1.6) and high refraction layer (refractive index 1.7-1.9) have distinct optical characteristics tailored to their specific functions. The low refraction layer handles light from the cover plate, while the high refraction layer manages light directed toward the display area, with each layer's optical properties optimized for its local function to maintain overall display uniformity
Solution Approach 2:
The patent creates dynamic light routing that adapts to different viewing angles. The total reflection interface at the high refraction layer dynamically redirects oblique incident light toward the front viewing area, while still allowing normal incident light to pass through to the display area. This dynamic optical behavior maintains display uniformity across different viewing angles while enhancing front side brightness
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
Enhances display brightness and reduces power consumption by optimizing the total reflection interface to enhance light emission, especially at the front side, while maintaining display uniformity across different viewing angles.
Implementation Method 1
the side surface of the low refraction layer facing the light-emitting area and the high refraction layer are in contact with each other to form a total reflection interface, wherein the total reflection interface is configured to allow display light emitted from the light-emitting area and incident through the high refraction layer to perform total reflection
Implementation Method 2
a low refraction layer arranged on an emergent light side of the display substrate... a high refraction layer arranged on a side of the low refraction layer facing away from the display substrate... a refractive index of the high refraction layer is greater than the refractive index of the low refraction layer
Data Source
AI summary
A display panel includes a light-transmitting area and a display area including a first and a second display area, the first display area and the light-transmitting area constitute a transparent display area; the display area includes: a display substrate including a light-emitting area and a non-light-emitting area; a low refraction layer; a high refraction layer, the high refraction layer covering at least the light-emitting area and a side surface of the low refraction layer facing the light-emitting area; the refractive index of the high refraction layer is greater than that of the low refraction layer, the side surface of the low refraction layer facing the light-emitting area is in contact with the high refraction layer to form a total reflection interface, the total reflection interface is configured to allow the display light emitted from the light-emitting area and incident through the high refraction layer to perform total reflection.