Half-Mirror Positioning Optics for Thermal Drift Alignment
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Solution Overview
Problem
In ultra-high precision positioning, thermal expansion of optical components causes deviation in the optical path, leading to misalignment and reduced accuracy between the optical systems for recognizing chip components and substrates, which deteriorates the positioning accuracy.
Innovation Solution
A positioning device using a configuration with a first and second half mirror, a camera, and computation equipment to capture and analyze images from both the joining head and stage sides, determining positions based on marked references, thereby maintaining alignment accuracy despite thermal expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If thermal expansion of optical components is allowed to occur naturally, then the device structure remains simple and flexible, but the optical path deviates causing misalignment and reduced positioning accuracy
Solution Approach 1:
A mark is introduced as an intermediary reference element that is visually connected to both the first and second members. The mark serves as a mediator that allows the optical system to recognize position relationships between members without requiring direct optical alignment between the members themselves, thereby compensating for thermal expansion effects.
Solution Approach 2:
The position information of members is copied onto the mark, which then serves as a reference for position recognition. By capturing images of the mark and its visual connection to members, the system creates a reference copy that remains stable despite thermal expansion of the optical components.
2Reliability
If the optical path is made stable against thermal expansion, then positioning accuracy is maintained, but the optical system becomes more complex requiring additional components like half mirrors and marks
Solution Approach 1:
The mark acts as an intermediary that simplifies the optical system by eliminating the need for complex thermal compensation mechanisms. Instead of making the optical path itself stable against thermal expansion, the mark provides a stable reference that is visually connected to members, allowing the optical components to remain simple while maintaining alignment stability.
3Device complexity
If a single camera is used to reduce device complexity, then the device structure is simplified, but it becomes difficult to capture both members simultaneously for position recognition
Solution Approach 1:
The mark serves as a intermediary reference that enables a single camera to capture position information of both members simultaneously. By visually connecting the mark to both members in a single field of view, the system allows one camera to measure the position relationship between members without requiring multiple cameras or complex switching mechanisms.
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 suppresses the decrease in positioning accuracy by minimizing optical path deviations due to thermal expansion, ensuring precise alignment of components.
Implementation Method 1
the first half mirror reflects light incident from a direction of the joining head toward the camera
Implementation Method 2
the second half mirror reflects light incident from a direction of the stage toward the camera
Data Source
AI summary
When a prism is disposed between a head and a stage, a half mirror reflects light incident from the direction of the head toward a camera. When the prism is disposed between the head and the stage, another half mirror reflects light incident from the direction of the stage toward the camera. The camera captures a camera image including a first image area, a second image area, and marks on the basis of light incident from the prism. Here, the first image area is image data of the side where the head is located, and the second image area is image data of the side where the stage is located. The marks are provided at positions seen through at least one of the two half mirrors when viewed from the camera.