Reflective Optical Sensor Parabolic Mirror Coupling Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional reflective optical sensors have low coupling efficiency due to diffuse light emission, resulting in a small amount of reflected light being detected, especially when the object has high reflectance, limiting their effectiveness in various applications.
Innovation Solution
A reflective optical sensor design featuring a parabolic first and second concave mirror configuration within an open box case, where the light emitting element emits light near the focal point of the first concave mirror, which is reflected to the object and then focused onto the second concave mirror, enhancing coupling efficiency by converting diffuse light into collimated light for improved detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If diffuse light is emitted onto the object, then most light is irradiated onto the object, but the amount of reflected light incident on the light receiving element is small resulting in low coupling efficiency
Solution Approach 1:
The patent applies curved reflective surfaces (concave mirrors with parabolic or spherical shapes) to collect and redirect light. The first concave mirror collects diffuse light from the light emitting element and reflects it as parallel light onto the object, while the second concave mirror collects reflected light from the object and focuses it onto the light receiving element, significantly improving coupling efficiency
Solution Approach 2:
The patent changes the optical parameters by using concave mirrors with specific focal lengths and curvature radii. By adjusting the focal length of the first concave mirror to match the distance from the light emitting element, and the focal length of the second concave mirror to focus light onto the light receiving element, the system optimizes light collection and coupling efficiency
2Productivity
If the light emitting element irradiates diffuse light, then light coverage is broad, but coupling efficiency remains low at about 5%
Solution Approach 1:
The patent introduces concave mirrors as intermediary optical elements between the light emitting element and the object, and between the object and the light receiving element. These mirrors act as mediators to redirect and concentrate light, transforming diffuse light into parallel beams and then focusing reflected light, thereby improving both coupling efficiency and detection intensity
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 design significantly improves coupling efficiency, allowing for consistent light irradiation regardless of distance and widening the effective detection range, while protecting the sensor components with sealing resin and preventing misdetection with a light blocking wall.
Implementation Method 1
light emitted by the light emitting element toward the first concave mirror from a position at or near the first focal point is reflected by the first concave mirror and irradiated to the object to be detected
Implementation Method 2
the reflected light reflected by the object to be detected is irradiated on the second concave mirror, and the light receiving element is configured to detect reflected light reflected by the second concave mirror so as to focus on the second focal point
Implementation Method 3
the first concave mirror and the second concave mirror each have a parabolic surface including an apex of a parabola formed by rotating the parabola around a symmetry axis of the parabola as a reflecting surface
Data Source
AI summary
A reflective optical sensor, which detects an object to be detected by detecting light reflected by the object by means of a light emitting element and a light receiving element, has an case of an open box shape in which first and second concave mirrors each having a reflective parabolic surface are formed. These first and second concave mirrors are formed so that the symmetry axes of the first and second concave mirrors intersect with a predetermined intersection angle on opposite side to the apexes of the first and second concave mirrors with respect to first and second focal points of the mirrors. Light emitted by the light emitting element travels through the first concave mirror, the object, the second concave mirror and the light receiving element.