TOF Sensor Optical Waveguide for Distance Accuracy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional distance measuring sensors using the time of flight (TOF) method face accuracy issues due to errors caused by the proximity of light emitting and receiving parts, particularly when mounted on devices like robot cleaners, where external light interference and reflections from windows can lead to incorrect measurements.
Innovation Solution
A distance measuring sensor assembly with a housing containing a first lens, a sensor module, a reception part spaced apart from the first lens, a second lens, and an optical waveguide part that focuses light onto a light receiving part, minimizing external light interference and ensuring accurate distance measurement by using a specific wavelength and reflective parts for efficient light transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the light emitting part and light receiving part are disposed adjacent to each other in a conventional TOF sensor, then the sensor can be miniaturized for compact applications, but measurement accuracy deteriorates due to external light interference and reflections from protective windows
Solution Approach 1:
The patent positions the light receiving part at a different spatial location than the light emitting part, using a folded optical path with mirrors and waveguides to redirect light from the object to the receiver. This dimensional separation eliminates direct line-of-sight interference from external light sources and window reflections while maintaining compact overall sensor dimensions.
Solution Approach 2:
The patent introduces optical intermediaries including mirrors, beam splitters, and waveguides to transfer light from the emitting part to the receiving part indirectly. These intermediary components enable the light to traverse a longer path through controlled reflections and refractions, separating the functional locations of emission and reception while blocking direct external light interference.
2Reliability
If a protective window is added to shield the sensor from external light, then sensor protection improves, but measurement accuracy worsens due to light reflections from the window surface
Solution Approach 1:
The patent introduces mirrors and beam splitters as intermediary optical elements between the protective window and the light receiving part. These intermediaries redirect the light path such that light reflected from the window surface is directed away from the receiver, while light from the object is properly directed to the receiver, thus eliminating window reflection interference.
Solution Approach 2:
The patent applies anti-reflective coatings to specific surfaces of the protective window and optical components. By modifying the local optical properties (reflectivity) of specific surfaces rather than the entire system, the patent reduces unwanted reflections from the window while maintaining protection functionality.
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 prevents external light interference and ensures accurate distance measurement by focusing light onto the light receiving part, enhancing the accuracy and efficiency of the distance measuring sensor assembly, particularly in applications like robot cleaners.
Implementation Method 1
a first lens provided on an upper part of the housing; a sensor module which is provided inside the housing and includes a light emitting part aligned with the first lens and emitting light toward an object
Implementation Method 2
a second lens which is provided under the reception part and refracts the light introduced from the reception part
Implementation Method 3
an optical waveguide part which is coupled to the second lens and guides the light transmitted from the second lens to the light receiving part
Implementation Method 4
a distance measuring sensor assembly using a time of flight (TOF) method which improves accuracy of measuring a distance
Data Source
AI summary
A distance measuring sensor assembly and an electronic device having the same, the sensor assembly including: a housing; a first lens provided at an upper part of the housing; a sensor module provided inside the housing, and having a light emitting part aligned with the first lens and emitting light toward an object, and a light receiving part disposed to be adjacent to the light emitting part. A reception part is provided at the upper part of the housing and spaced apart from the first lens. The light reflected from the object enters through the reception part. A second lens is provided at a lower part of the reception part and refracts the light entering from the reception part, and an optical waveguide part coupled to the second lens is used to guide the light having transmitted from the second lens to the light receiving part.