Sub-Optical Patterns for Touch Sensing in LCDs
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Solution Overview
Problem
Current display devices face challenges in acquiring touch information while maintaining wide viewing angles and preventing deterioration of display quality.
Innovation Solution
Incorporating sub-optical patterns within the pixels of a liquid crystal display device, these patterns are designed to be recognized by opto-electronic pens without reducing the aperture area, allowing for touch information acquisition while maintaining the display's viewing angle characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sub-optical patterns are incorporated into pixels for touch information acquisition, then touch sensing capability is improved, but display quality and viewing angle characteristics may deteriorate
Solution Approach 1:
The patent applies local quality by making sub-optical patterns visible only to opto-electronic pens while keeping them invisible to human eyes. This is achieved by using patterns with specific optical characteristics (size, contrast, wavelength) that are detectable by the pen's sensor but not by human vision, thus enabling touch sensing without compromising display quality for human users.
Solution Approach 2:
The patent changes physical parameters of the sub-optical patterns, specifically their size (smaller than human visual resolution), contrast (low visibility to humans), and wavelength (potentially UV or IR components undetectable by human eye). These parameter changes allow the patterns to serve dual purposes: being detectable by opto-electronic pens for touch information while remaining imperceptible to human users, thus resolving the contradiction between touch sensing and display quality.
2Adaptability or versatility
If sub-optical patterns are added to pixels, then touch sensing function is enhanced, but aperture area and luminance may be reduced
Solution Approach 1:
The patent applies partial action by incorporating sub-optical patterns that occupy only a small portion of the pixel area, specifically designed to be smaller than the human visual resolution threshold. This partial incorporation provides touch sensing capability while minimizing the impact on aperture area and luminance, as the patterns are just sufficient for opto-electronic pen detection without significantly blocking light transmission.
Solution Approach 2:
The sub-optical patterns are implemented as thin film structures integrated into the pixel layer, allowing them to be extremely thin and minimally intrusive. This thin film approach enables the patterns to provide touch sensing functionality while having negligible impact on light transmission and luminance, effectively resolving the contradiction between adding sensing functionality and maintaining display brightness.
3Adaptability or versatility
If multiple domains with different liquid crystal orientations are formed, then viewing angle is improved, but pixel structure complexity increases
Solution Approach 1:
The patent merges the sub-optical patterns with the domain structure by positioning them at domain boundaries or within specific domains. This merging allows the patterns to leverage the existing liquid crystal orientation differences for enhanced visibility to opto-electronic pens while maintaining the multi-domain structure's viewing angle benefits, thus improving touch sensing without proportionally increasing complexity.
Solution Approach 2:
The sub-optical patterns serve multiple functions simultaneously: they act as domain identifiers for opto-electronic pen detection, maintain liquid crystal alignment at boundaries, and provide structural support. This multi-functionality reduces the need for additional separate components, thereby enhancing touch sensing capability while minimizing the increase in pixel structure 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 solution enables the display device to acquire touch information effectively while preserving the wide viewing angles and display quality, ensuring that the presence of sub-optical patterns does not significantly impact the luminance or color accuracy across different viewing angles.
Implementation Method 1
The liquid crystal display generates an electric field in the liquid crystal layer by applying voltage to the field generating electrodes
Implementation Method 2
determines the direction of liquid crystal molecules of the liquid crystal layer by the generated electric field, thus controlling polarization of incident light
Implementation Method 3
a light alignment method of controlling an alignment direction and an alignment angle of the liquid crystal by irradiating light to a photosensitive alignment layer
Data Source
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AI summary
Touch-related information which cannot be acquired by the naked eye (dubbed here as sub-optical pattern information) has its corresponding sub-optical patterns respectively positioned within the aperture areas of respective domains such that the displayed image, as viewed from different viewing angles is not adversely affected by the embedded sub-optical patterns. One type of touch-related information which can be conveyed is that of touch location of a sub-optical pattern sensing pen positioned over one or more of the sub-optical patterns.