Touch Display Polarization Layers for Reduced Mesh Pattern Visibility
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Solution Overview
Problem
Display devices with touch sensing functions face issues with external light reflection, particularly when the touch conductive layer has a curved surface, causing the pattern to be visually recognizable due to phase shift of reflected light.
Innovation Solution
Incorporating a reflection preventing unit with a polarization layer and phase retardation layers, including a λ/4 and λ/2 phase retardation value, to minimize light reflection and reduce visibility of touch conductive layer patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a touch conductive layer with a mesh pattern is used to implement touch sensing function, then touch detection capability is improved, but the pattern of the touch conductive layer becomes visually recognizable due to light reflection
Solution Approach 1:
A reflection preventing unit comprising a polarization layer and phase retardation layers is introduced as an intermediary between the touch conductive layer and external light. The polarization layer blocks reflected light from the curved surface of the touch conductive layer, while the phase retardation layers manipulate light polarization states to enhance the effectiveness of the polarization layer in preventing pattern visibility.
Solution Approach 2:
The invention changes the optical parameters of light by introducing phase retardation layers with specific retardation values (λ/4 and λ/2). These layers alter the polarization state of reflected light, transforming it into a state that can be effectively blocked by the polarization layer, thereby preventing the touch conductive layer pattern from being visually recognized.
2Object-affected harmful factors
If a reflection preventing unit is added to reduce external light reflection, then pattern visibility is reduced, but device complexity increases
Solution Approach 1:
The reflection preventing unit is segmented into multiple functional layers: a polarization layer for blocking reflected light and phase retardation layers (with λ/4 and λ/2 values) for manipulating light polarization. This segmentation allows each layer to perform its specific function efficiently, achieving effective pattern obscuration while maintaining a systematic and manageable structure.
3Ease of operation
If the touch conductive layer has a curved surface to follow the display, then touch sensing performance is improved, but light phase shift occurs causing pattern leakage
Solution Approach 1:
The polarization layer acts as an intermediary that blocks the phase-shifted reflected light from the curved touch conductive layer. The phase retardation layers serve as additional intermediaries that manipulate the polarization state of the reflected light, ensuring that even light undergoing phase shifts due to the curved surface is effectively blocked, preventing pattern leakage.
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
Effectively reduces external light reflection, preventing the pattern of the touch conductive layer from being recognized, enhancing display device performance.
Implementation Method 1
a reflection preventing unit disposed on the touch unit and including a polarization layer
Implementation Method 2
a first phase retardation layer disposed between the touch unit and the polarization layer and having a λ/4 phase retardation value, and a second phase retardation layer disposed between the first phase retardation layer and the polarization layer and having a λ/2 phase retardation value
Data Source
AI summary
A display device includes a display unit including: a plurality of light emitting diodes; a touch unit disposed on the display unit and including a touch conductive layer of a mesh type; and a reflection preventing unit disposed on the touch unit and including a polarization layer. The touch conductive layer includes a plurality of first conductive lines extending in a first direction and a plurality of second conductive lines extending in a second direction crossing the first direction, and an angle between the second direction and an absorption axis of the polarization layer is about 5±10°.