Angle Detection Device Using Time-Multiplexed AFE Switching
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Solution Overview
Problem
Conventional angle detection devices face challenges in synchronizing light detection by multiple photodetectors and processing digital image data from multiple analog-front-ends (AFE) simultaneously, leading to difficulties in accurately detecting horizontal and vertical angles simultaneously.
Innovation Solution
The angle detection device configures a control section with fewer AFEs than photodetectors, using a signal switch to sequentially connect photodetectors to a single AFE for data processing, allowing simultaneous light emission and reception, and converting analog signals into digital signals for the CPU, thereby reducing the number of AFEs required and improving data processing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If four AFEs are used to simultaneously process signals from four photodetectors, then simultaneous angle detection is achieved, but device complexity increases
Solution Approach 1:
The patent merges multiple AFE functions into a single AFE by using a sequential switching mechanism. The signal switch connects different photodetectors to the same AFE at different time points, allowing one AFE to process signals from multiple photodetectors that were simultaneously illuminated. This reduces the number of AFEs from four to one while maintaining angle detection capability.
Solution Approach 2:
The patent implements periodic switching of the signal switch to sequentially connect different photodetectors to the AFE. The switching occurs in a timed sequence that corresponds to the integration periods of each photodetector, allowing the AFE to process signals from photodetector 1, then 2, then 3, then 4 in succession. This periodic action enables time-multiplexed processing of simultaneously acquired optical signals.
2Ease of operation
If four digital data memories are used to store data from four AFEs, then data processing is simplified, but device complexity and cost increase
Solution Approach 1:
The patent merges the data storage function from four separate digital data memories into a single digital data memory. Since the AFE sequentially processes signals from all four photodetectors and stores the integrated values in one memory location, only one digital data memory is needed to hold the final angle detection results. This eliminates three memory components while maintaining full data storage capability.
Solution Approach 2:
The single digital data memory serves the function that would otherwise require four separate memories. The memory is universally used to store the integrated signal values from all four photodetectors after they are sequentially processed by the AFE. This multi-functional use of a single memory component reduces device complexity while maintaining the ability to store and process data from all detection channels.
3Productivity
If multiple AFEs are used to simultaneously convert analog signals to digital signals, then processing speed is improved, but manufacturing cost increases
Solution Approach 1:
The patent merges four separate AFE conversion functions into a single AFE by using time-multiplexed sequential processing. The AFE converts analog signals from photodetector 1, then 2, then 3, then 4 in succession during their respective integration periods. While the conversion is sequential rather than perfectly simultaneous, the overall processing maintains the timing requirements for accurate angle detection while reducing component count and manufacturing cost.
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 enables accurate simultaneous detection of horizontal and vertical angles with a simpler circuit design, reducing the need for multiple AFEs and enhancing processing speed, while preventing signal deterioration and maintaining detection accuracy.
Implementation Method 1
a plurality of photodetectors 36 (third photodetector 363 and fourth photodetector 364) for receiving the lights 35L (third light 35L3 and fourth light 35L4)
Data Source
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AI summary
An angle detection device (30) includes photoemitters (35), photodetectors (36), a scale plate (34) disposed therebetween, and a control section (33) to control them. The control section (33) includes an AFE (43) to convert analog signals (Ia) of the photodetectors (36) to digital signals (Id) and an arithmetic processor (44) to detect a rotating posture of the scale plate (34) based on the digital signals (Id). The control section (33) simultaneously emits lights from the photoemitters (35) and simultaneously receives the lights by the photodetectors (36). The control section (33) then executes the following data processing for each photodetector (36) one by one in sequence: outputting the analog signals representing an entire area of a light-receiving area of one of the photodetectors and outputting the digital signals converted by the AFE to the processor (44).