Optical Handwriting Input Using Position-Encoded Barcode Layer
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Solution Overview
Problem
Existing handwriting input apparatuses, such as resistive touch panels and thin-film transistors substrates, face issues with low detecting speed, high cost, poor transmittance, and short product life due to unsupported elastic conductive films and manufacturing flatness challenges, which affect their performance on display panels.
Innovation Solution
A handwriting input apparatus featuring a position-encoding layer with 2D or 1D barcodes, a projector, and a camera, where the position-encoding layer is transparent to visible light and reflective to infrared, allowing for high-resolution detection without the need for spacers and using a multi-layer structure to maintain display quality and reduce costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a resistive touch panel is used for handwriting input, then the structure is simple, but the detecting speed is too slow to meet handwriting input requirements
Solution Approach 1:
The patent replaces the mechanical pressure-based detection system with an optical detection system. Instead of using elastic conductive films that require physical contact and pressure sensing, the invention uses a position-encoding layer with barcodes that is read optically by a camera, eliminating mechanical constraints and enabling faster detection suitable for handwriting input.
Solution Approach 2:
The patent uses optical copying to detect position information. Rather than directly sensing physical contact through elastic films, the system captures an optical image (copy) of the position-encoding patterns and processes this image data to determine touch location, enabling non-contact and faster detection.
2Speed
If a thin-film transistors substrate is used for handwriting input, then the detecting speed is fast, but the manufacturing cost is high and transmittance is poor
Solution Approach 1:
The patent replaces expensive thin-film transistors with a more economical position-encoding layer consisting of barcodes printed on a transparent substrate. This simpler, cheaper structure achieves the required functionality without the high manufacturing costs associated with TFT substrates.
Solution Approach 2:
The patent changes the detection principle from electrical (TFT-based voltage sensing) to optical (barcode reading). This parameter change allows the use of transparent materials that do not interfere with display light transmission, solving the transmittance problem while maintaining fast detection speeds through efficient optical recognition.
3Reliability
If a thin-film transistors substrate with elastic conductive film is used, then handwriting detection is enabled, but the product life is short due to unsupported elastic conductive film
Solution Approach 1:
The patent removes the elastic conductive film and spacer components from the structure. By extracting these problematic elements, the invention eliminates the source of reliability issues (unsupported elastic film degradation) while simplifying the overall structure to just the position-encoding layer and optical reading system.
Solution Approach 2:
The patent uses optical imaging to capture position information without physical contact. The camera reads the position-encoding patterns optically, eliminating the need for elastic conductive films that physically degrade over time, thereby extending product life while maintaining detection functionality.
4Ease of operation
If elastic conductive film is used without sufficient support, then flexibility is achieved, but manufacturing flatness control becomes difficult
Solution Approach 1:
The patent replaces the elastic conductive film with a rigid position-encoding layer that has inherent flatness. Optical copying allows the system to read position information from this flat, stable structure without requiring the flexibility and flatness control challenges associated with elastic films.
Solution Approach 2:
The patent substitutes the mechanical elastic conductive film system with an optical reading system. This replacement eliminates the need for flexible but hard-to-control elastic materials, using instead a stable position-encoding layer that is read optically, thereby solving the flatness control problem while maintaining operational ease.
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 solution provides high detecting speed and resolution, extends product life, and is more economical than traditional methods, while ensuring compatibility with display panels without compromising image quality.
Implementation Method 1
The position-encoding layer is transparent to visible light and reflective to light of predetermined wavelengths
Implementation Method 2
The projector generates a light beam of the predetermined wavelengths toward the position-encoding layer
Implementation Method 3
The camera capturing images of the plurality of position-encoding patterns
Data Source
AI summary
A handwriting input apparatus comprises a position-encoding layer and a pen. The position-encoding layer comprises a plurality of position-encoding pattern. The position-encoding layer is transparent to visible light and is reflective to light of predetermined wavelengths. Each position-encoding pattern represents a specific code. The pen has a projector and a camera at one end. The projector is adapted to generate a light beam of the predetermined wavelengths toward the position-encoding layer. The camera is adapted to capture images of the plurality of position-encoding pattern.