Optical Stylus Dynamic Focal Length Adjustment
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Solution Overview
Problem
Existing styluses for two and three-dimensional applications are limited by the need for physical contact or close proximity to the screen, restricting their use to rough graphical input within a two-dimensional plane and lacking versatility for 3D applications.
Innovation Solution
An optical stylus with a dynamic optical element that adjusts focal length based on separation distance, allowing for independent identification of in-focus position-encoding patterns, enabling both 2D and 3D mode operation through a control unit and distance measurement sensor, and optionally incorporating a pressure sensor or functional button for mode switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If physical contact or very small separation is used between stylus and screen, then measurement precision is improved, but adaptability is worsened
Solution Approach 1:
The patent implements a dynamic optical element (variable focal length lens) that can adjust its focal length based on the separation distance between the stylus and the position-encoded surface. This dynamic adjustment allows the stylus to maintain focus and accurate position determination across varying distances, resolving the contradiction between requiring close proximity for precision and needing adaptability for versatile 3D applications
Solution Approach 2:
The patent changes the optical parameter (focal length) of the optical arrangement as a function of separation distance. By electrically actuating the dynamic optical element to adjust focal length based on measured distance, the system maintains measurement precision across different separation distances, enabling both contact mode (2D) and hover mode (3D) operations
2Adaptability or versatility
If dynamic optical element with focal length adjustment is added, then adaptability is improved, but device complexity is worsened
Solution Approach 1:
The patent integrates multiple functions into a single optical system. The same optical arrangement with variable focal length lens serves both 2D contact mode operation and 3D hover mode operation. The control unit manages both focal length adjustment based on distance measurements and mode switching, consolidating multiple functions into one unified system rather than requiring separate systems for 2D and 3D applications
3Measurement precision
If distance measurement sensor and focal length adjustment are implemented, then measurement precision is improved, but use of energy is worsened
Solution Approach 1:
The system dynamically adjusts the focal length only when needed for 3D hover mode operation. In 2D contact mode, the optical element remains in a fixed focal length state, consuming minimal energy. The control unit switches between operational modes based on separation distance, activating the energy-consuming focal adjustment mechanism only when the stylus is in hover mode, thus managing energy consumption based on actual operational requirements
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 accurate two and three-dimensional position determination, expanding the stylus's application range to include 3D engineering design, technical sketching, and artistic drawings, while maintaining energy efficiency in 2D mode and extended detection range in 3D mode.
Implementation Method 1
The distance measurement sensor is a time-of-flight sensor
Implementation Method 2
an optical arrangement comprising a dynamic optical element configured to be electrically actuated in order to adjust the focal length of the optical stylus
Data Source
AI summary
The invention relates to an optical stylus (10) for an optical position determination device (1) comprising a position-encoded surface (50) having different position-encoding patterns (52). The optical stylus (10) comprises a housing (12) including: an image sensor (20) for capturing at least one image of any position-encoding pattern (52) of the position-encoded surface (50): an optical arrangement (15) comprising a dynamic optical element (16) configured to be electrically actuated in order to adjust the focal length of the optical stylus (10) as a function of a separation distance (D) between a reference point of the optical stylus (10) and the position of any position-encoding pattern (52) to have a substantially in-focus position-encoding pattern (52) corresponding to the position of the optical stylus (10), and a control unit (24) to control the dynamical optical element (16). The optical stylus further comprises a distance measurement sensor (32) to measure the separation distance (D). The control unit (24) is adapted for actuating the dynamic optical element (16) to adjust the focal length of the optical stylus (10) as a function of the output signal of the distance measurement sensor (32).