Optical Pen Input for Graphical Displays
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Solution Overview
Problem
Existing electronic devices face challenges in providing cost-effective and reliable methods for handwritten user input on graphical displays, as they often suffer from unintended contact issues with touch screens and require complex designs for pen movement tracking.
Innovation Solution
A pen-like device with an optical pattern tracking component that captures images of a surface beneath its tip, allowing it to determine movement and communicate with electronic devices, which can display an optical tracking grid to support the pen's operation and disable touch screen inputs when in use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If touch sensors are incorporated into the display screen to detect stylus motion, then handwritten input capability is enabled, but unintended contact detection occurs when user rests palm on display
Solution Approach 1:
The input detection function is segmented between two separate systems: the optical pen provides precise tip location through image analysis of the display surface, while the touch screen handles general contact detection. This segmentation allows the optical pen to ignore palm contact and the touch screen to handle intentional touches, resolving the reliability issue while maintaining handwritten input capability.
Solution Approach 2:
The optical pen acts as an intermediary between the user's hand and the display screen. Instead of directly detecting hand contact through the display, the optical pen captures images of the display surface and processes them to determine pen tip location, thereby filtering out unintended palm contact while preserving intentional input.
2Ease of operation
If optical sensor in pen tip is used with pre-printed dot matrix paper to track motion, then pen movement can be determined, but the system is limited to paper and requires complex gyroscopic tracking
Solution Approach 1:
Instead of using complex gyroscopic sensors to directly measure pen motion, the system creates an optical copy of the display surface through image capture. The pen tip location is determined by analyzing the captured images of the display surface features, replacing complex mechanical motion sensing with simpler optical imaging and image processing.
Solution Approach 2:
The mechanical gyroscopic tracking system is replaced with an optical imaging system. The pen tip position is determined not by mechanical sensors but by capturing images of the display surface and processing these images to calculate position, thereby reducing device complexity while maintaining motion tracking capability.
3Ease of operation
If specialized sensors are incorporated into the display to track stylus motion, then handwritten input is enabled, but the device complexity and cost increase
Solution Approach 1:
The display screen serves multiple functions: it acts as both the visual output device and the optical tracking surface for the pen. By displaying a patterned surface that can be captured by the pen's optical sensor, the display enables handwritten input tracking without requiring separate specialized sensors, thereby reducing device complexity and cost.
Solution Approach 2:
The display screen performs self-service by providing the optical tracking pattern directly on its surface. The display's own visual output serves as the tracking reference for the optical pen, eliminating the need for external specialized sensors and reducing overall system 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
Enables efficient and cost-effective handwritten input on graphical displays with reduced errors from unintended contacts, improving user convenience and device usability by allowing free-form entry of data without mode changes.
Implementation Method 1
an optical sensor in its tip, and this pen-like device is used in conjunction with special paper that has a matrix of dots pre-printed thereon. The optical sensor in the tip of the pen-like device periodically captures images of the paper, and its pre-printed dots
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
Methods and apparatuses of obtaining user input. A display of an optical tracking grid (110, 804) is initiated (604, 702) on an electronic graphical display (104, 334, 802). Changes are determined (608, 714) among images of at least a portion of the optical tracking grid that are captured by a tracking pen device (120, 122, 318). Based on the determined changes in the images, a movement of a portion of the tracking pen device is determined (608, 716). A data set characterizing movement is produced in response to determining the movement (718).