Position Detection Device Invalid Area Setting
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Solution Overview
Problem
Existing position detection systems erroneously detect a user's hand or sleeve as a pointing device when the user's hand or sleeve unintentionally touches the screen, leading to incorrect identification of the pointing position.
Innovation Solution
A position detection device that includes a position detection unit, a direction determination unit, and a setting unit, which sets an invalid area based on the position pointed by a first pointer and its pointing direction, thereby preventing erroneous detection of the hand or sleeve as a second pointer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the position detection system detects positions based on light emission and reflection across the entire detection area, then the detection coverage and versatility are improved, but erroneous detection of hand or sleeve as pointing devices occurs
Solution Approach 1:
The patent applies local quality by creating an invalid area with different detection properties than the valid area. The invalid area is positioned opposite to the pointing direction of the first pointer, where hand or sleeve contact is most likely to occur. This localized differentiation allows the system to maintain high detection coverage while preventing erroneous detections in specific problematic regions.
Solution Approach 2:
The detection area is segmented into a valid area and an invalid area. The invalid area is specifically positioned opposite to the pointing direction of the first pointer, creating distinct zones with different detection rules. This segmentation allows the system to process detections differently based on location, improving reliability without sacrificing overall detection coverage.
2Ease of operation
If the system uses a general-purpose pointer detection method for both first and second pointers, then the ease of operation is improved, but the ability to distinguish between intentional pointing and unintentional contact deteriorates
Solution Approach 1:
The system performs preliminary action by pre-defining an invalid area opposite to the pointing direction of the first pointer before detection occurs. This preliminary setup allows the system to automatically filter out erroneous detections without adding complexity to the detection process itself, maintaining ease of operation while improving measurement precision.
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 prevents erroneous detection of the hand or sleeve as a pointing device by setting an invalid area opposite to the pointing direction of the first pointer, simplifying the processing and improving accuracy in position detection.
Implementation Method 1
a first pointer (light pen) which emits light
Implementation Method 2
a position detection unit which detects a position pointed by a first pointer and a position pointed by a second pointer
Data Source
AI summary
A projector includes: a position detection unit which detects a position pointed by a light pen (first pointer) and a position pointed by a user's finger or the like (second pointer) within a detection area; a state determination unit which determines a pointing direction of the light pen; and an invalid area setting unit which sets an invalid area where the position pointed by the second pointer is invalid, within the detection area, based on the position pointed by the light pen detected by the position detection unit and the pointing direction of the light pen determined by the state determination unit.