Three-Dimensional, Real-Time, and High-Accuracy Inline Monitoring System for Roll to Roll Manufacturing

Abstract

A non-contact, real-time, high-accuracy, low-cost, broad-range, and full-field 3D shape measurement technique is presented. The technique is based on a generalized fringe projection profilometry approach, and it employs random phase shifting, doublefrequency projection fringes, ultrafast direct phase unwrapping, and inverse self-calibration schemes to perform 3D shape determinations with enhanced accuracies in a real-time manner. The measurement accuracy can reach 1/10000 of the field of view or higher, and the acquisition speed is capable of achieving 5 to 30 3D views per second. Experiments have been conducted to verify the validity of the proposed technique. Due to its superior capability, the real-time, high-accuracy 3D shape measurement technique is very suitable for inline monitoring the flexible electronics products during roll to roll manufacturing, and it can also serve as an experimental tool to investigate the mechanical/thermal reliability issues involved in flexible electronics design and optimization analysis.Three-dimensional (3D) shape measurement techniques for the determination of 3D shapes of objects have emerged as important tools for product inspection and quality control applications in electronics industry. Typical 3D shape measurement techniques, such as laser scanning method [1], moire method [2], interferometry method [3], photogrammetry method [4], laser tracking method [5], digital image correlation (DIC) method [6], and fringe (or structured light) projection method [7-16],generally fall into two categories. One is capable of providing accurate measurement, and the other is capable of supplying fast measurement. The techniques in the former category such as coordinate measurement and laser-based measurement methods are capable of providing accurate 3D imaging, but the measurement speed is usually very low because these techniques measure various points on the object sequentially. On the contrary, the techniques in the fast measurement category generally yield relatively faster 3D imaging with lower accuracies.As the technologies of electronics design and manufacturing evolve, there has been a high demand for the 3D shape measurement and monitoring techniques to provide not only accurate, but also realtime measurements. For example, the manufacturing of electronic components needs an inspection process that can measure and analyze various 3D features on the components and determine whether the desired features are within the tolerance specifications or not. In this application, both high inspection speed and high accuracy are required because the inspection speed must match the manufacturing speed. Measurement errors can result in erroneous inspection that leads to an acceptable part being rejected or a defective part being accepted. At present, however, a technique capable of providing both real-time and high-accuracy 3D shape measurement and 3D imaging is lacking and is highly on demand.In this paper, a non-contact, real-time, highaccuracy, low-cost, broad-range, and full-field 3D s...

Laser inspection of rubber profiles

“…Similar to this, an 'in line' system is reported which allows monitoring of a 'roll-to-roll' production process. It allows a wide range and high accuracy 3D monitoring of flexible electronic products and components which are manufactured in 'roll-to-roll' technology (Zhaoyang et al, 2008). Although the reviewed methods have their advantages, this paper focuses on their main drawback: the use of highly expensive equipment which, in addition, is also susceptible to environment; it is worth noting that the operating environment for 'in-line' measuring is far more aggressive than that for 'off line' equipment.…”