Chuck Table Optical Path for Imaging Film-Backed Workpieces
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Solution Overview
Problem
Existing processing apparatuses face challenges in imaging the front face of a workpiece with a metal film or resin film on the rear face, as they require removal of the film from the outer edge, leading to high processing loads and costs due to the need for thick cutting blades.
Innovation Solution
A processing apparatus with a chuck table featuring a light passing portion and a holding portion for negative pressure, where the light passing portion includes a first mirror face to reflect light and allow imaging of the workpiece's front face through the light passing portion, enabling the camera unit to detect the front face without the need for film removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a camera unit that can detect light of a wavelength that passes through the workpiece is used to image the front face through the workpiece, then the front face can be imaged when the rear face is exposed, but a metal film or resin film on the rear face blocks the light and prevents imaging
Solution Approach 1:
The chuck table is divided into a holding portion for suction and a light passing portion for optical transmission. This segmentation allows the system to simultaneously maintain workpiece holding capability and enable light transmission for imaging through the workpiece, resolving the contradiction between imaging requirements and the presence of light-blocking films.
Solution Approach 2:
An optical system including mirrors and a beam splitter is introduced as an intermediary to redirect light paths. The first mirror reflects light from the light passing portion, the second mirror reflects light from the workpiece front face, and the beam splitter combines these light paths to the camera. This intermediary optical system enables imaging through the workpiece even when films are present on the rear face.
2Measurement precision
If a metal film or resin film is removed from the outer peripheral edge of the workpiece to enable imaging, then the front face can be imaged through the workpiece, but an edge trimming apparatus with a thick cutting blade is required, increasing processing load and cost
Solution Approach 1:
The chuck table is segmented into a holding portion and a light passing portion. The light passing portion is specifically designed to transmit light for imaging without requiring removal of the workpiece edge films. This segmentation eliminates the need for edge trimming operations, reducing processing load and costs while maintaining imaging capability.
Solution Approach 2:
The imaging function is extracted from the workpiece edge region and relocated to the light passing portion of the chuck table. By positioning the camera to image through the light passing portion rather than requiring edge transparency, the system removes the requirement for film removal operations, thereby reducing processing complexity and cost.
3Adaptability or versatility
If the workpiece is processed with the front face directed downwardly, then processing can be carried out for certain workpiece types or processes, but the front face cannot be imaged through the workpiece when a metal film or resin film is present on the rear face
Solution Approach 1:
The chuck table is segmented into distinct functional regions: a holding portion for workpiece attachment and a light passing portion for optical access. This segmentation enables the system to accommodate workpieces processed in various orientations while maintaining imaging capability through the light passing portion, regardless of film presence on the rear face.
Solution Approach 2:
An optical intermediary system comprising mirrors and a beam splitter is introduced to enable imaging when the workpiece front face is directed downwardly. The first mirror receives light from the light passing portion, the second mirror captures reflected light from the workpiece front face, and the beam splitter directs both light paths to the camera, enabling imaging in downward-facing configurations.
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
Enables easy imaging of the workpiece's front face held by the chuck table, reducing processing load and cost by eliminating the need for extensive film removal and thick cutting blades, while accurately detecting scheduled division lines for precise processing.
Implementation Method 1
the light passing portion has a first mirror face that reflects light that advances from the first region into the light passing portion
Implementation Method 2
the light passing portion has a first mirror face that reflects light that advances from the first region into the light passing portion
Data Source
AI summary
A processing apparatus includes a chuck table for sucking and holding a workpiece and a camera unit imaging the workpiece. The chuck table includes a light passing portion that passes light. The light passing portion includes a first region that overlaps with the workpiece and has a first mirror face that reflects light that advances from the first region into the light passing portion. The camera unit can image the workpiece by detecting light reflected by the first mirror face after having been reflected by the workpiece held by the chuck table and advanced into the light passing portion.