Optical Sensor Cap Structure for Ambient Light Shielding
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Solution Overview
Problem
Optical sensing systems face interference from ambient and reflected light, particularly in the visible and non-visible spectrum, which affects the accuracy of proximity detection and material recognition applications.
Innovation Solution
An optical sensing apparatus with a covering cap and encapsulating structure that shields or absorbs interfering light, featuring a substrate with a light-receiving and light-emitting device, an adhesive layer, and a design that prevents adhesive overflow into openings, ensuring accurate light path alignment and enhanced mechanical reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a covering cap is added to shield interfering light, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The covering cap is nested within the encapsulating structure, with the cap positioned inside the encapsulation to shield the optical components from interfering light while maintaining a compact integrated design
Solution Approach 2:
An adhesive layer is introduced as an intermediary between the covering cap and the encapsulating structure, enabling secure attachment while preventing direct contact that could cause adhesive overflow into the optical opening
2Reliability
If adhesive layer is used to attach covering cap, then reliability is improved, but adhesive may overflow into openings causing manufacturing defects
Solution Approach 1:
The adhesive layer is applied locally at the periphery of the encapsulating structure, specifically in regions away from the optical opening, ensuring secure attachment without risking overflow into the opening where it would interfere with light transmission
Solution Approach 2:
The potential harmful effect of adhesive overflow is prevented by strategically positioning the adhesive application area away from the critical optical opening, extracting the adhesive placement from the region near the opening
3Object-affected harmful factors
If covering cap extends beyond encapsulating structure, then light shielding is improved, but alignment precision deteriorates
Solution Approach 1:
The covering cap is designed with an asymmetric configuration where the cap opening is smaller than the encapsulating structure opening, allowing the cap to provide effective shielding while maintaining proper alignment within the encapsulation boundaries
Solution Approach 2:
The covering cap design preemptively prevents misalignment issues by ensuring the cap dimensions and positioning are configured to fit within the encapsulating structure boundaries, preventing potential alignment errors before assembly
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 solution effectively reduces interference from ambient and reflected light, improving the accuracy of optical sensing applications by ensuring that only targeted light reaches the light-receiving device, thereby enhancing the reliability and precision of proximity detection and material recognition.
Implementation Method 1
the covering cap includes a material configured to shield or absorb a NIR light or a SWIR light
Implementation Method 2
the encapsulating structure may include a material transparent to a NIR light or a SWIR light
Implementation Method 3
the light-receiving device may include a photoelectronic device having a detecting region comprising germanium
Data Source
AI summary
Systems, apparatuses, and methods for optical sensing are provided. For example, an optical sensing apparatus can include a substrate, a light-receiving device, a light-emitting device, an encapsulating structure, a covering cap, and an adhesive layer. The light-receiving device and the light-emitting device can be disposed on and electrically connected to the substrate. The encapsulating structure can be disposed on the substrate and cover the light-emitting device and the light-receiving device. The encapsulating structure can include a top surface, a first side surface, and a lower surface. The first side surface and the lower surface can collectively form a recess. The covering cap can be disposed on the encapsulating structure and can include a first opening, a top portion, a protruding portion, and an extending portion. The adhesive layer can be arranged between the encapsulating structure and the covering cap to adhere the encapsulating structure and the covering cap.