Photovoltaic Cell Cover Layer for Accurate Laser Power Sensing
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Solution Overview
Problem
Photovoltaic cells used in wireless laser power transmission systems face inefficiencies due to tradeoffs between Ohmic and optical losses, inaccurate power measurements, and safety concerns from reflected light, particularly when illuminated from different angles or by various light sources.
Innovation Solution
The design incorporates a cover layer with anti-reflective coatings and a grid structure that reflects light in a wide pattern, reducing Ohmic losses and recycling reflected light, while the cover layer absorbs or reflects unwanted wavelengths to enhance measurement accuracy and safety by minimizing reflections and trapping laser beams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the cover layer transmits all wavelengths, then laser beam transmission is maximized, but unwanted wavelengths affect power measurement accuracy
Solution Approach 1:
The patent applies wavelength-selective properties to specific regions of the electromagnetic spectrum while maintaining broadband transmission for the laser wavelength. The anti-reflective coatings are designed with optical properties that create a transmission window at the laser wavelength (700nm-1500nm) while blocking or absorbing other wavelengths, thereby achieving local quality optimization for different wavelength ranges.
Solution Approach 2:
The patent modifies the optical parameters of the cover layer and anti-reflective coatings to achieve wavelength-dependent transmission characteristics. By adjusting the thickness, refractive index, and material composition of the anti-reflective coatings, the system creates selective transmission windows that pass the laser wavelength while blocking other wavelengths, thereby improving measurement accuracy without sacrificing energy conversion efficiency.
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 improves efficiency, aiming accuracy, and safety by reducing optical losses, increasing the coverage area of conductors, and providing accurate power measurements independent of illumination direction, thus ensuring safe and efficient energy conversion from laser beams.
Implementation Method 1
The design incorporates a cover layer with anti-reflective coatings and a grid structure that reflects light in a wide pattern
Implementation Method 2
Photovoltaic cells, known as PV cells, are designed and used in many systems to convert light (visible or invisible) into electrical energy
Implementation Method 3
the cover layer comprising a material adapted to restrict transmission, by either absorption or reflection, of illumination having wavelengths outside of the range of the wavelength of the laser beam
Implementation Method 4
a grid structure that reflects light in a wide pattern, reducing Ohmic losses and recycling reflected light
Data Source
Figure 1
Figure 2~3
Figure 4A~4C
AI summary
A wireless optical power transmission system comprising a transmitter and receiver, the transmitter comprising a laser emitting a beam, a scanning mirror for steering the beam towards said receiver and a control unit receiving signals from a detection unit on the receiver and controlling the beam power and the scanning mirror. The receiver has a photovoltaic cell having a bandgap energy of 0.75-1.2 e V, with a plurality of conductors on a beam receiving surface. A cover layer of material blocking illumination of wavelengths outside that of the laser, is disposed on the photovoltaic cell. The cover layer may have anti-reflective coatings on its top and bottom surfaces. The detection unit thus generates a signal representing the power of the laser beam impinging upon the receiver, independent of illuminations other than that of said laser beam. The control unit thus can maintain the laser power impinging on the receiver.