Curved Surface Light Guide Tube for Wide-Angle Detection
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Solution Overview
Problem
In systems where an input device is tracked using a camera, especially when mounted on a head-mounted display, it is challenging to ensure that light from the light emitting portion is detectable regardless of the posture of the input device, affecting the accuracy of position and posture calculation.
Innovation Solution
The input device incorporates a light guide tube with a curved surface that widens the angle range of light emitted from the light emitting portion, making it easier to detect the light with a camera and improving the calculation accuracy of the input device's position and posture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a light guide tube is used to guide light from the light source to the light emitting portion, then the light can be directed to the outer surface, but the angle range of emitted light is limited making it difficult to detect regardless of input device posture
Solution Approach 1:
A curved surface is formed at the boundary surface between light media in the optical path from the incident surface to the outer surface of the light emitting portion. This curved surface refracts light to widen the angle range of emitted light, enabling detection from multiple camera positions and input device postures.
Solution Approach 2:
The refractive index distribution is changed by forming a curved surface at the boundary between light media. This parameter change in the optical path modifies the light propagation characteristics, widening the emission angle range while maintaining light guidance functionality.
2Device complexity
If the light emitting portion emits light in a narrow angle range, then the light guide tube structure is simple, but the camera cannot detect the light when the input device is in certain postures
Solution Approach 1:
The curved surface is formed directly on the boundary between light media within the existing light guide tube structure, rather than adding separate optical components. This approach widens the light emission angle without significantly increasing device complexity.
3Volume of moving object
If the light emission angle is narrow, then the light guide tube can be compact, but the light becomes undetectable when the camera position relative to the input device varies
Solution Approach 1:
The curved surface is integrated into the boundary between light media within the compact light guide tube volume. This curvature refracts light to widen the emission angle range without increasing the overall size of the light guide tube, enabling detection from various camera positions.
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 widened angle range of light emitted from the light emitting portion enhances detectability by the camera, thereby improving the accuracy of calculating the input device's position and posture, even in varying postures.
Implementation Method 1
A curved surface that widens an angle range of light which exits from an outer surface is formed at a boundary surface between light media in an optical path from an incident surface of the light guide tube to the outer surface of the light emitting portion
Data Source
AI summary
Provided is an input device including an exterior member; a light source housed in the exterior member; a tracked portion that is a part of the exterior member and includes a light emitting portion having an outer surface that emits light toward an outside; and a light guide tube that has an incident surface that receives light of the light source and guides the light of the light source to the light emitting portion, in which a curved surface that widens an angle range of light emitted from the outer surface of the light emitting portion is formed at a boundary surface between light media in an optical path from the incident surface of the light guide tube to the outer surface of the light emitting portion.