Flexible Light Guide and Optical Layer for Narrow-Bezel Displays
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Solution Overview
Problem
Existing display devices face challenges in achieving narrow bezels due to the placement of light sources between the display panel and the user, which complicates the design and limits the ability to minimize the bezel size.
Innovation Solution
A display device incorporating a flexible light guide with a light source portion disposed on the display side and a light entrance portion on the back side of the display panel, utilizing a flexible light guide with a Young's modulus of 10 to 1000 MPa and a thickness of 100 μm to 200 μm, and optical layers with a refractive index difference of 0.1 to 0.2, allowing the light emitting element to be positioned on the back side, thus enabling a narrow bezel design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the light source is placed between the display panel and the user (front light source), then the display structure is simple, but the bezel size cannot be minimized
Solution Approach 1:
The light guide is bent into a three-dimensional configuration with a bending radius of less than 1 mm, allowing the light source portion to be positioned on the display side while the light entrance portion is positioned on the back side. This spatial reconfiguration enables the light emitting element to be placed on the back side of the display panel, achieving narrow bezel design without complicating the display structure
Solution Approach 2:
A flexible light guide with Young's modulus of 10 to 1000 MPa and thickness of 100 μm to 200 μm is used, which can be bent by a bending radius of less than 1 mm. This flexible structure allows the light guide to be configured in a three-dimensional manner, enabling the light source portion to be disposed on the display side while the light entrance portion is disposed on the back side, thus achieving narrow bezel design
2Length of stationary object
If the light emitting element is positioned on the back side of the display panel, then the bezel size is minimized, but the light guide structure becomes more complex
Solution Approach 1:
The patent uses a flexible light guide with specific mechanical properties (Young's modulus of 10 to 1000 MPa, thickness of 100 μm to 200 μm) that can be bent by a bending radius of less than 1 mm. This flexibility allows the light guide to achieve the required three-dimensional configuration without adding significant structural complexity, as the bending is accomplished through material properties rather than complex mechanical structures
Solution Approach 2:
The patent optimizes the physical parameters of the light guide, including Young's modulus (10 to 1000 MPa), thickness (100 μm to 200 μm), and bending radius (less than 1 mm), to enable the light guide to be bent and positioned in a three-dimensional configuration. These parameter changes allow the light guide to achieve the desired shape and positioning without requiring complex structural designs
3Ease of manufacture
If the optical layer completely covers the flexible light guide, then the manufacturing process is simplified, but the light utilization efficiency decreases
Solution Approach 1:
The optical layer is selectively disposed only on the light source portion of the flexible light guide, with a thickness of 5 μm to 25 μm. This local coverage approach allows the optical layer to improve light extraction efficiency at the light source portion while avoiding unnecessary material deposition on other portions, thereby maintaining manufacturing simplicity while optimizing light utilization efficiency
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 allows for a narrow bezel design by positioning the light emitting element on the back side of the display panel, improving light utilization efficiency and brightness uniformity, with brightness efficiency reaching up to 190 Nits/W and contrast ratios of 20 in closed and 17.2 in open states.
Implementation Method 1
The flexible light guide includes a light source portion, a light entrance portion, and a middle portion between the light source portion and the light entrance portion. The middle portion is bent by a bending radius of less than 1 mm so that the light source portion is disposed on the display side of the display panel, and the light entrance portion is disposed on the back side of the display panel.
Implementation Method 2
The optical layer is disposed on and in contact with the surface of the light source portion of the flexible light guide. A difference of refractive index between the optical layer and the flexible light guide is in a range of 0.1 to 0.2.
Data Source
AI summary
A display device including a display panel, a flexible light guide having a Young's modulus of about 10 to 1000 MPa, a light emitting element, and an optical layer is provided. The flexible light guide includes a light source portion, a light entrance portion, and a middle portion. The middle portion is bent, so that the light source portion and the light entrance portion are disposed at the opposite sides of the display panel. The light emitting element is disposed adjacent to the light entrance portion of the flexible light guide with a light emitting surface facing the side edge of the flexible light guide. The optical layer is in contact with a surface of the light source portion and a difference of refractive index between the flexible light guide and the optical layer is in a range of 0.1 to 0.2.