Optical Sensor Cover Layout for Low-Crosstalk Proximity Sensing
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Solution Overview
Problem
Optical crosstalk in proximity sensor arrangements, where light emitted by the emitting device is reflected back by the cover or scattered by ink and detected by the detection device without reaching the object, leading to inaccurate sensor signals due to the close proximity of the emitting and detection devices.
Innovation Solution
The use of a cover layer with two openings above the emitting and detection devices, where one opening is camouflaged by a second cover layer with adapted optical properties, allowing for increased separation between the devices to reduce crosstalk, while maintaining invisibility to the human eye.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If only one aperture is used for both emitting device and detection device, then the device complexity is reduced, but the distance between emitting device and detection device becomes short causing increased optical crosstalk
Solution Approach 1:
The patent divides the single aperture into two separate apertures: a first aperture for the emitting device and a second aperture for the detection device. This segmentation allows increasing the distance between the emitting and detection devices, thereby reducing optical crosstalk while maintaining separate optical paths for each device.
2Measurement precision
If two openings are used to increase distance between devices, then optical crosstalk is reduced, but the visibility of openings increases affecting cosmetic appearance
Solution Approach 1:
The patent applies a cover layer with optical properties that match the surrounding cover plastic or glass. By adapting the color, transparency, or optical characteristics of the cover layer to blend with the surrounding material, the openings become effectively invisible or significantly less visible to the human eye, thus maintaining cosmetic appearance while allowing two separate apertures for reduced crosstalk.
3Adaptability or versatility
If cover layer with openings is used, then device functionality is improved, but manufacturing precision requirements increase due to alignment of multiple layers
Solution Approach 1:
The patent introduces a cover layer as an intermediary element that bridges the openings and the surrounding cover material. This cover layer serves as a mediator that can be optically adapted to match the surrounding material, allowing the openings to be hidden while maintaining their functional purpose. The cover layer acts as a transition zone that simplifies the manufacturing alignment requirements by providing a flexible optical interface.
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 configuration effectively reduces optical crosstalk by increasing the distance between the emitting and detection devices, improving detection accuracy while maintaining a visually unified appearance.
Implementation Method 1
A reflection and/or an absorption characteristics for incident light within a specified spectrum of visible light of one of the second and third cover layer is adapted to a reflection and/or an absorption characteristics of the first cover layer for incident light within the specified spectrum
Implementation Method 2
the respective opening is camouflaged or disguised by adapting said optical properties
Implementation Method 3
an emitting device and a detection device. The emitting device is configured to emit electromagnetic radiation
Implementation Method 4
the detection device is configured to detect electromagnetic radiation... detect the light returning after being reflected by an object
Implementation Method 5
light may get reflected by the cover or scattered by the ink and consequently be detected without having left the sensor arrangement and reached an object. This phenomenon is denoted as optical crosstalk
Data Source
Figure 1A~2
Figure 3A~4
AI summary
An optical sensor arrangement comprises an emitting device (E) and a detection device (D) configured to emit and detect, respectively, electromagnetic radiation and a cover (C) arranged to cover the emitting and the detection device (E, D). The sensor arrangement comprises a first cover layer (Cl) partially covering an inner surface of the cover (C) and having a first and a second opening located above the emitting and the detection device (E, D), respectively. The sensor arrangement comprises a second and a third cover layer (C2, C3) covering the inner surface at areas of the first and the second opening. A reflection and/or an absorption characteristics of at least one of the second and third cover layer (C2, C3) is adapted to a reflection and/or an absorption characteristics of the first cover layer (Cl) for incident light within the specified spectrum.