Polarizing Unit Structure to Prevent Bending in Thin Displays
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Display devices with thin profiles and lightweight structures face challenges in maintaining reliability due to bending issues in the polarizing unit, which is exacerbated by differences in moisture expansion coefficients of the coefficient of materials such as the coefficient of moisture expansion of the polarizing unit.
Innovation Solution
The display device incorporates a polarizing unit with a first and second optical film having similar moisture expansion coefficients and a third optical film with a different coefficient, symmetrically arranged to balance tensile forces to mitigate deformation, and a third optical film with a λ/4 phase retardation layer to prevent bending.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the display device is made thinner and lighter to improve portability, then the profile and weight are reduced, but the polarizing unit becomes prone to bending and reliability deteriorates
Solution Approach 1:
The patent employs a composite structure consisting of multiple optical films (first optical film, second optical film, and third optical film) with different material properties. This composite arrangement creates a balanced mechanical structure that resists bending while maintaining the thin profile requirement. The combination of films with varying coefficients of moisture expansion and tensile strengths provides both lightweight characteristics and structural reliability.
2Length of moving object
If the display device is made thinner to improve portability, then the profile is reduced, but the polarizing unit bends due to unequal expansion of layers
Solution Approach 1:
The patent applies local quality by assigning different functional characteristics to each optical film layer. The first optical film has a first coefficient of moisture expansion, the second optical film has a second coefficient, and the third optical film has a third coefficient. This differentiation allows each layer to contribute specific properties, with the overall structure achieving bending resistance through the coordinated expansion behavior of individual layers with varying local characteristics.
Solution Approach 2:
The patent utilizes the coefficients of moisture expansion of the optical films to prevent bending. By carefully selecting materials with specific expansion coefficients for each layer, the structure achieves dimensional stability. The first, second, and third optical films are chosen to have coordinated expansion characteristics that counteract bending forces when the display device undergoes thickness changes or environmental humidity variations.
3Reliability
If a multi-layer structure is used in the polarizing unit to prevent bending, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The patent achieves multi-functionality by designing each optical film layer to serve multiple purposes. The first, second, and third optical films collectively provide polarization functions while simultaneously serving as a mechanical structure to prevent bending. The same layers that perform optical functions also provide structural support through their coordinated expansion characteristics, eliminating the need for separate reinforcement components and reducing overall device complexity.
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 symmetric arrangement of optical films with varying moisture expansion coefficients and a λ/4 phase retardation layer prevents the bending of the polarizing unit, thereby enhancing the bending characteristics of the display device.
Implementation Method 1
The first optical film may have a first coefficient of moisture expansion, the second optical film may have a second coefficient of moisture expansion, and the third optical film may have a third coefficient of moisture expansion. The first coefficient of moisture expansion and second coefficient of moisture expansion may be substantially the same, while the third coefficient of moisture expansion may differ from the first coefficient of moisture expansion and the second coefficient of moisture expansion.
Implementation Method 2
The third optical film may include a λ/4 phase retardation layer. Light passing through the first optical film may be non-polarized, and light passing through the second optical film may be polarized.
Data Source
AI summary
A display device includes a substrate, a display layer, a thin-film encapsulation layer, and a polarizing unit. The polarizing unit includes a first optical film disposed on the thin-film encapsulation layer and having a first coefficient of moisture expansion, a second optical film disposed on the first optical film and having a second coefficient of moisture expansion, and a third optical film disposed between the first and second optical films and having a third coefficient of moisture expansion. The first and second coefficient of moisture expansion are substantially the same. The first optical film may include a PVA resin film, the second optical film may include a PVA resin film and iodine, and the third optical film may include a λ/4 phase retardation layer. Light passing through the first optical film may be non-polarized, and light passing through the second optical film may be polarized.