Optical Filter Layer Layout for Higher-Contrast Detection
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Solution Overview
Problem
Optical detection devices face challenges in guiding light reflected from objects to be detected efficiently, leading to reduced contrast and detection accuracy due to light directly incident on light-receiving elements.
Innovation Solution
A detection device is designed with a photosensor, a front light system including a light guide plate and a light source, and an optical filter layer with light guide paths and a light-blocking portion, where the light guide paths overlap the light-receiving elements and are configured to tilt the intensity peak of emitted light towards the opposite side of the light source, reducing noise and improving sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a light guide plate is disposed on the front side of light-receiving elements to illuminate the object, then the object can be illuminated, but light traveling in the opposite direction directly incident on the light-receiving element leads to reduced contrast
Solution Approach 1:
The optical filter layer is segmented into multiple functional regions: light guide paths for transmitting reflected light to light-receiving elements, light-blocking portions for absorbing stray light, and openings for light emission. This segmentation allows different areas to perform specialized functions, effectively separating the illumination function from the detection function to prevent contrast degradation.
Solution Approach 2:
Different regions of the optical filter layer are assigned different optical properties: light guide paths have high light transmission in specific directions, light-blocking portions have high absorptance, and openings allow light emission. This local differentiation of optical qualities enables the system to maintain both effective illumination and high detection contrast by controlling light behavior in different locations.
2Reliability
If light-receiving elements are arranged on a substrate to detect light, then detection capability is provided, but guidance of reflected light to light-receiving elements needs improvement
Solution Approach 1:
The optical filter layer serves as an intermediary component between the light guide plate and the light-receiving elements. It mediates the light path by guiding reflected light through light guide paths to the light-receiving elements while blocking stray light through light-blocking portions, thereby improving the effectiveness of light guidance and enhancing detection precision.
Solution Approach 2:
The light guide paths are configured with specific geometric arrangements including offsets between first openings and second openings, and tilted peak directions of emitted light. This dimensional configuration controls the directionality of light transmission, ensuring that reflected light is effectively guided to the light-receiving elements while preventing stray light from reaching them.
3Measurement precision
If an optical filter layer with light guide paths is provided between light-receiving elements and front light, then light guidance is improved, but device complexity increases
Solution Approach 1:
The optical filter layer performs multiple functions simultaneously: it guides reflected light to light-receiving elements through light guide paths, blocks stray light through light-blocking portions, and allows emission of light through openings. By integrating these multiple functions into a single component, the design improves detection accuracy without proportionally increasing device complexity.
Solution Approach 2:
The optical filter layer can be constructed using composite structures combining different materials with specific optical properties: light-transmitting materials for light guide paths, light-absorbing materials for light-blocking portions, and appropriate structural configurations for openings. This composite approach enables the layer to achieve complex optical functions while maintaining manufacturing feasibility.
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 configuration enhances detection accuracy by selectively transmitting light in a tilted direction, reducing noise and improving the signal-to-noise ratio, thereby increasing the sensitivity and accuracy of light detection.
Implementation Method 1
The light guide plate includes a scattering portion configured to scatter the light from the light source on the optical filter layer side
Implementation Method 2
The optical filter layer includes light guide paths that at least partially overlap the light-receiving elements and a light-blocking portion that has higher absorptance of the light than the light guide paths
Implementation Method 3
a photosensor including a plurality of light-receiving elements configured to receive light
Data Source
AI summary
According to an aspect, a detection device includes: a photosensor including light-receiving elements; a front light including a light guide plate and a light source configured to emit light to a first side surface of the light guide plate; and an optical filter layer provided between the light-receiving elements and the front light. The optical filter layer includes light guide paths and a light-blocking portion. A first opening of each light guide path closest to the light-receiving elements is offset in a direction more away from the light source than a second opening of the light guide path farthest from the light-receiving elements. The light guide plate includes a scattering portion on the optical filter layer side. A first peak of an intensity of first light emitted from the detection surface of the light guide plate is observed to be tilted toward a side opposite to the first side surface.