CSP Lens Shape Inspection via Collimated Light Refraction
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Solution Overview
Problem
The existing technologies face challenges in accurately measuring the shape of lenses on chip size package (CSP) solid-state image pickup elements, as they are prone to warping or deformation, leading to defective products and yield deterioration during manufacturing.
Innovation Solution
An inspection apparatus utilizing collimated light and a transmission filter with regularly arranged holes to capture images of the lens, comparing them with ideal images to assess the shape and performance of the CSP solid-state image pickup element, including a calculation unit to determine deviations and thresholds for inspection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If contact measurement method is used to measure lens shape, then measurement can be performed, but the glass face of the CSP solid-state image pickup element is damaged
Solution Approach 1:
The patent introduces an intermediary optical system consisting of a transmission filter with holes and a collimated light source. This intermediary setup allows indirect measurement of the lens shape by observing how the lens refracts light patterns, eliminating the need for direct contact between the measurement device and the glass face, thus preventing damage while enabling accurate measurement
Solution Approach 2:
The patent replaces the mechanical contact measurement system with an optical measurement system. Instead of using physical probes or contact-based instruments that directly touch the lens and glass face, the system uses collimated light, transmission filters, and image capture to non-contactively measure lens shape through optical refraction patterns
2Measurement precision
If microscope observation is used to measure lens shape, then measurement can be performed, but accurate measurement is difficult and yield deteriorates
Solution Approach 1:
The patent creates an optical copy or projection of the lens shape information by using collimated light that passes through the transmission filter and is refracted by the lens. The resulting light pattern captured by the imaging device is a copy of the lens shape characteristics, enabling accurate measurement without the limitations of direct microscope observation
Solution Approach 2:
The patent changes the measurement parameters by using collimated light with specific wavelengths and transmission filters with specific hole patterns. This parameter change transforms the measurement approach from direct visual observation through a microscope to optical projection and pattern analysis, achieving higher accuracy and better suitability for automated inspection
3Volume of moving object
If CSP solid-state image pickup element is miniaturized and thickness is reduced, then miniaturization is achieved, but the element warps or bends during manufacturing
Solution Approach 1:
The patent applies preliminary action by performing inspection of the lens shape and element flatness early in the manufacturing process, before final assembly. The collimated light measurement system detects warping or bending issues in advance, allowing for corrective actions to be taken before the defective elements are assembled into final products, thereby maintaining quality despite miniaturization
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 simple and accurate inspection of the lens shape on CSP solid-state image pickup elements, improving yield and reducing manufacturing costs by identifying and excluding defective products before assembly.
Implementation Method 1
a collimated-light generation unit configured to generate collimated light
Implementation Method 2
a transmission filter configured to transmit part of the collimated light and block another part of the collimated light different from the part of the collimated light
Implementation Method 3
a lens configured to condense the incident light to the CSP solid-state image pickup element
Implementation Method 4
a chip size package (CSP) solid-state image pickup element configured to capture an image including a pixel signal corresponding to a quantity of incident light
Data Source
AI summary
The present disclosure relates to an inspection apparatus and an inspection method that enable inspection of the performance of an image pickup element. Generation of collimated light and transmission of part of the collimated light through a transmission filter having a light-blocking face provided with circular holes arranged regularly, causes conversion to rays of columnar collimated light arranged regularly. An image including the rays of columnar collimated light arranged regularly, is captured by an image pickup element being inspected. Then, acquisition of the difference between the image captured by the image pickup element being inspected and an ideal image captured by an ideal image pickup element and comparison between the difference and a threshold, result in inspection of the performance of the image pickup element being inspected.