Curved Wiring Lines in PDLC Display Devices
Solution Overview
Problem
Display devices using polymer dispersed liquid crystal (PDLC) often experience degradation in display quality due to highly-directional scattering of light caused by linearly-extended wiring lines, leading to variations in luminance based on the viewing direction.
Innovation Solution
The display device incorporates a design where the scanning lines and signal lines are curved between the light-emitting element and the pixel electrodes, reducing the directivity of scattered light and minimizing luminance unevenness by using a polymer dispersed liquid crystal layer with aligned polymer and liquid crystal molecules between substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If linearly-extended wiring lines are used in the display panel, then the device complexity is reduced and manufacturing is simplified, but highly-directional scattering occurs causing luminance variations according to viewing direction
Solution Approach 1:
The patent applies curvature to the third wiring line by introducing a curved portion that extends in the first direction between the first and second wiring lines. This curved geometry transforms the linear light scattering path into a more isotropic scattering pattern, reducing the highly-directional scattering effect that causes luminance variations. The curved wiring line maintains electrical connectivity while fundamentally changing the light interaction characteristics.
2Device complexity
If point light sources are arranged at the ends of the display panel, then the illumination device structure is simplified, but light scattering by wiring lines causes degradation of display quality
Solution Approach 1:
The patent applies local quality by making only the third wiring line (scanning line) curved between the light-emitting element and pixel electrodes, while the first and second wiring lines (signal lines) remain linear. This localized modification targets the specific wiring line that causes the most significant scattering interference with the light path, optimizing display quality without requiring redesign of the entire wiring structure.
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
This design effectively suppresses the degradation of display quality by reducing the directivity of scattered light, resulting in consistent luminance distribution regardless of the viewing direction, enhancing the overall display performance.
Implementation Method 1
display devices using polymer dispersed liquid crystal (hereinafter referred to also as PDLC) which can switch between a diffusion state in which entering light is diffused and a transmission state in which entering light is transmitted
Implementation Method 2
These wiring lines may cause highly-directional scattering to light which is emitted from the point light sources to the display panel
Data Source
AI summary
According to one embodiment, a display device includes a first substrate, a second substrate, a liquid crystal layer held between the first and the second substrates, and a light-emitting element including light-emitting portions arranged in a first direction. The first substrate includes first and second wiring lines, and a third wiring line which intersects the first and the second wiring lines. The first and the second wiring lines extend in a second direction. The third wiring line has a first side located on a side close to the light-emitting element. The first side has a first curved portion which is curved between the first and the second wiring lines.