Bifurcated End Effector Light Scanning for Substrate Inclination Diagnosis
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Solution Overview
Problem
Existing substrate transfer apparatuses struggle to accurately diagnose the state of substrates, such as inclination, due to their reliance on binary signal conversion from continuously changing light output values.
Innovation Solution
The apparatus includes a robot arm with a bifurcated end effector that emits and receives light, allowing the control device to compare measured waveforms with reference waveforms to diagnose substrate, FOUP, and end effector states based on relative positional relationships.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the output value from the light receiving unit is converted into a binary signal to detect substrate presence, then the detection process is simplified, but the ability to accurately diagnose substrate state (such as inclination) is lost
Solution Approach 1:
The patent extracts only the necessary information for substrate state diagnosis from the continuous output signal, rather than converting the entire signal to binary. The control device selectively processes the continuous output value to extract diagnostic information about substrate inclination and position, maintaining measurement precision while avoiding unnecessary complexity.
Solution Approach 2:
The system performs preliminary diagnosis of substrate state by analyzing the continuous output signal characteristics before binary conversion or final decision-making. The control device evaluates the continuous signal to determine substrate inclination and position, enabling accurate diagnosis while simplifying subsequent control decisions.
2Measurement precision
If the light scanning operation is performed to measure substrate position and diagnose state, then accurate diagnosis is achieved, but the operation time increases
Solution Approach 1:
The light scanning operation is performed continuously or repeatedly during the substrate transfer process rather than as a separate discrete step. The light emitting unit and light receiving unit continuously monitor substrate position and state during the robot arm's movement, enabling accurate diagnosis without adding significant time loss to the overall transfer operation.
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 solution enables accurate diagnosis of substrate states, including inclination, and detects changes in light intensity or sensitivity, improving the overall precision and reliability of substrate transfer operations.
Implementation Method 1
a light receiving unit configured to convert detection light into an output value continuously changed depending on an amount of received light
Implementation Method 2
the control device controls an operation of the robot arm so that light traveling through a tip of the end effector scans edges of a plurality of substrates accommodated in a front opening unified pod (FOUP)
Data Source
AI summary
A substrate transfer apparatus includes a base, an arm, an end effector provided at a tip of the arm and having first and second tip portions that are bifurcated, a light emitting unit, a light receiving unit, and a control device controlling an operation of the arm. The control device controls an operation of the arm so that light straightly traveling through a tip of the end effector scans edges of a plurality of substrates accommodated in a front opening unified pod (FOUP), and compares shape patterns of a measured waveform of an output value continuously changed in the light receiving unit with shape patterns of a reference waveform for comparison according to a relative positional relationship between the light and substrate during the operation of the arm and diagnoses at least one of a state of the substrate, the FOUP, and the end effector based on a comparison result.