Inclined Light Guide Geometry for Compact Gesture Sensing
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Solution Overview
Problem
Existing gesture and proximity detection interfaces for vehicle passenger compartments require a large number of light guides with limited incline angles, leading to bulkier and more expensive designs due to the need for multiple printed circuit boards and fasteners to maintain inclined lighting modules.
Innovation Solution
A light guide with an inner diopter and a second planar face inclined at a specific angle, allowing for the emission of light beams centered about a plane inclined by angles greater than 25°, enabling more compact and efficient gesture detection systems by using a single printed circuit board for both light sources and detectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple light guides with limited incline angles are used to cover a large detection space, then the detection coverage is improved, but the device complexity and bulkiness increase due to requiring multiple printed circuit boards and fasteners
Solution Approach 1:
The patent changes the incline angle parameter of the light guide from the conventional less than 15° to greater than 25°, enabling a single light guide to cover a larger detection space. This parameter change eliminates the need for multiple light guides and their associated printed circuit boards and fasteners, thereby reducing device complexity while maintaining or improving detection coverage.
2Measurement precision
If the number of light guides is increased to improve hand position tracking accuracy, then the measurement precision is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
By increasing the incline angle parameter of the light guide to greater than 25°, the patent enables a single light guide to provide sufficient light coverage for accurate hand position tracking. This eliminates the need to increase the number of light guides, thereby maintaining measurement precision while reducing device complexity and manufacturing cost.
3Area of stationary object
If multiple inclined lighting modules are used to achieve large detection space coverage, then the detection space coverage is improved, but the manufacturing cost increases
Solution Approach 1:
The patent changes the incline angle parameter to greater than 25°, allowing a single light guide to cover a large detection space. This reduces the number of light guides and associated components (printed circuit boards, fasteners) that need to be manufactured and assembled, thereby reducing manufacturing cost while maintaining detection space coverage.
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 allows for more compact and potentially less expensive gesture sensors with increased incline angles, enabling accurate hand position tracking and gesture analysis while reducing the bulkiness and cost of the interface module.
Implementation Method 1
an inner diopter intended to face a printed circuit board bearing a light source or a light detector, forming a converging lens whose focal point is located at an expected position of the source or of the light detector
Implementation Method 2
a first planar face oriented parallel to the optical axis of the light guide, a second planar face inclined with respect to the first planar face by an angle α
Data Source
AI summary
One subject of the invention is a light guide (13), for an interface module, in particular for a vehicle passenger compartment, for emitting or receiving a light beam in a cone that is elongate in a transverse direction and that is centred on a plane that is inclined by an angle θ with respect to an optical axis (z) of the light guide, taking the form of a prism made of transparent material of index nGL, characterised in that it comprises: •an interior dioptric interface intended to face a printed circuit board (7) bearing a light source (5) or a light detector, forming a convergent lens the focal point of which is located at an expected position of the light source (5) or of the light detector, •a first planar face (15) that is oriented parallel to the optical axis (z) of the light guide, and •a second planar face (17) that is inclined with respect to the first face (15) by an angle α respecting cos(α+θ)=(1−ε) nGL*cos 3α, with ε a number comprised between −0.1 and 0.1.