Sensor Module Lens Shielding for Stray Light Blocking
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Solution Overview
Problem
In sensor modules, manufacturing tolerances lead to openings in covers being larger than lenses, allowing light to bypass the lens and directly incident on sensors, reducing accuracy and signal-to-noise ratio, causing 'ghost targets' and decreased performance.
Innovation Solution
A recess around the convex lens is filled with a liquid opaque material that cures to form a solid, aligning with the lens and preventing light from passing adjacent to it, ensuring only light that passes through the lens reaches the sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the opening diameter is increased to accommodate manufacturing tolerances, then the ease of assembly is improved, but the measurement precision deteriorates due to light bypassing the lens
Solution Approach 1:
The patent introduces an opaque material specifically at the location where light bypass occurs (around the lens periphery), creating a localized light-blocking structure. This allows the opening to remain large for ease of assembly while preventing stray light from reaching the sensor, thus maintaining measurement precision without compromising manufacturing ease.
Solution Approach 2:
The opaque material acts as an intermediary element between the lens and the sensor, blocking stray light that would otherwise bypass the lens and directly illuminate the sensor. This intermediary structure resolves the contradiction by allowing large openings while preventing measurement errors caused by light bypass.
2Ease of manufacture
If the opening diameter is increased to accommodate manufacturing tolerances, then the ease of assembly is improved, but the signal to noise ratio deteriorates due to ghost targets
Solution Approach 1:
The opaque material is strategically placed only in the region where stray light interferes with sensor performance (around the lens), allowing the overall opening to remain large for easy assembly. This localized approach maintains signal-to-noise ratio by blocking ghost targets while preserving manufacturing ease.
Solution Approach 2:
The opaque material serves as an intermediary that blocks stray light paths without interfering with the primary optical path through the lens. This resolves the contradiction by improving reliability (signal-to-noise ratio) while maintaining ease of assembly through large openings.
3Device complexity
If a single piece cover is used to reduce device complexity, then the device complexity is reduced, but the manufacturing precision deteriorates due to alignment tolerances
Solution Approach 1:
The patent maintains the simple single-piece cover structure but adds a localized opaque material feature around the lens. This local addition allows the cover to remain simple and easy to manufacture while the opaque material compensates for alignment tolerances by blocking stray light that would otherwise cause precision issues.
Solution Approach 2:
The opaque material structure is designed to automatically compensate for alignment variations between the cover opening and the lens. The material's positioning and extent are configured to ensure that even with manufacturing tolerances, stray light is effectively blocked, making the system self-compensating for alignment errors.
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 improves sensor accuracy and signal-to-noise ratio by preventing light from bypassing the lens, enhancing performance in bright conditions and extending the sensing range, while allowing for smaller, more efficient lens designs.
Implementation Method 1
The liquid may flow inwardly to form a meniscus against the lens
Implementation Method 2
The opaque material may be provided as a liquid which is then cured to become a solid
Data Source
AI summary
A sensor module including a sensor and a transparent body which is provided over the sensor, wherein the transparent body comprises a base portion and a convex lens which extends outwardly from the base portion and is located above the sensor, wherein an opaque material is provided on the base portion and surrounds the convex lens.