Optical Sensor Diffuser for Laser Safety and S/N Ratio
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional optical sensing apparatuses face challenges in improving the safety of laser products while maintaining a high Signal-to-Noise (S/N) ratio, particularly due to the limitations of apparent light source size and the impact of multiple scattering on the falling time and irradiating power.
Innovation Solution
The optical sensing apparatus incorporates a laser device with a diffusing member that refracts or diffracts light to create a more even intensity distribution, combined with a screen that enlarges the apparent light source size, thereby increasing the maximum permissible exposure (MPE) and accessible emission limit (AEL) while minimizing the influence of multiple scattering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If laser light is used for optical sensing, then measurement capability is improved, but safety of laser products deteriorates due to high irradiating power requirements
Solution Approach 1:
The patent transforms the point-like laser source into an extended line-shaped light source by introducing a diffusing member. This dimensional transformation increases the apparent light source size, which improves safety by reducing power density while maintaining total irradiating power for measurement capability.
Solution Approach 2:
The diffusing member acts as an intermediary between the laser light source and the measurement target. It refracts or diffracts the laser light to create a line-shaped illumination pattern, enabling safe operation at higher total power levels while distributing the intensity across a larger area.
2Measurement precision
If multiple scattering is reduced to improve S/N ratio, then measurement accuracy is improved, but light transmission efficiency deteriorates
Solution Approach 1:
The patent applies local quality by creating a line-shaped illumination pattern that concentrates light in a specific spatial distribution. This localized illumination approach improves the S/N ratio by enhancing signal strength from the measurement region while minimizing unnecessary light transmission through scattering-prone paths.
3Object-affected harmful factors
If apparent light source size is increased to improve safety, then MPE and AEL are increased, but light intensity distribution becomes less uniform
Solution Approach 1:
The patent transforms the point-like laser source into an extended line-shaped light source by introducing a diffusing member. This dimensional transformation increases the apparent light source size, which improves safety by reducing power density while maintaining total irradiating power for measurement capability.
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 enhances the safety of laser products by allowing higher irradiating power while maintaining a high S/N ratio, reducing the impact of multiple scattering and improving the accuracy of biometric measurements.
Implementation Method 1
the diffusing member refracting or diffracting the laser light to make the laser light lower in intensity in a first portion including a center of a cross-section of the laser light
Implementation Method 2
the diffusing member refracting or diffracting the laser light to make the laser light higher in intensity in a second portion of the laser light that surrounds the first portion
Implementation Method 3
enlarge a beam diameter of the laser light
Data Source
Figure 1~2A
Figure 2B~3C
Figure 3D~3F
AI summary
An optical sensing apparatus according to an embodiment of the present disclosure includes a laser device, a photodetector, and a control circuit. The laser device includes a light source that emits laser light, a diffusing member having a diffusing surface that crosses an optical path of the laser light, the diffusing member making the laser light lower in intensity in a first portion including a center of a cross-section of the laser light that crosses the optical path, making the laser light higher in intensity in a second portion of the laser light that surrounds the first portion in the cross-section, and enlarging a beam diameter of the laser light, and a screen, and irradiates a physical object with the laser light having passed through the screen or the laser light reflected by the screen. The control circuit causes the laser device to irradiate the physical object with at least one optical pulse of the laser light and causes the photodetector to perform a time-resolved measurement of at least one reflected optical pulse of the laser light returning from the physical object.