FLAT PANEL DISPLAYS


imaging,’ Lewis stated. ‘Our technology is camera-agnostic – it can be coupled with any type of camera-based inspection solution. At this stage, we integrate with any camera supplier, rather than producing our own camera technology.’ Te solution offered by InZiv is capable of


Teledyne Dalsa’s Linea ML line scan camera can perform multi-field imaging, enabling it to speed up inspection of FPDs


information – the wavelength of light being emitted from each measurement point in a pixel; refractive index; and the type of material involved in a defect. All of this can be used to determine where in the manufacturing process a defect originates. Tis information cannot be obtained with a camera.’ Te solution offered by InZiv is not only


able to detect the nature of defects, but can also be integrated into existing high-resolution camera-based solutions to deliver a display inspection platform capable of identifying both the location and type of defects present in displays. Te camera is used to perform a scan of the phone display, revealing any problem areas, which can then be inspected at higher resolution with InZiv’s solution to identify the type and origin of the defect. ‘Our technique can provide manufacturers


with a very accurate map of the 3D topography, combined with super-resolution optical


EXAMINING ELECTRONICS


Imaging in 3D is a valuable tool for examining printed circuit boards (PCBs) for defects such as missing solder joins, excess solder paste, rotated, misplaced, or even missing components.


Dr Athinodoros Klipfel, sales manager for 3D sensors at Automation Technology, described how one of the firm’s OEM customers used its 3D imaging technology, in combination with a colour line scan camera, to inspect surface mount device (SMD) assembly on PCBs. The system was able to identify


PCB defects, such as if multiple microchip pins had mistakenly been soldered together, or if an SMD component had been soldered


out of alignment relative to other components. ‘Around four years ago this customer was only using the line scan camera to inspect PCBs. However, this prevented them from detecting certain defects as they lacked depth information, meaning their machines weren’t as reliable as they could be,’ said Klipfel. ‘Now, using our 3D sensor, they have been able to increase their machines’ capability to detect defects and increase their reliability, providing added value to their customers.’ Imaging in 3D has been used


for PCB inspection for at least 15 years, according to Klipfel. However, compared to 15 years ago, a number of developments


18 Imaging and Machine Vision Europe • August/September 2019 There are also now larger sensors


A point cloud image of a PCB obtained using 3D imaging.


have taken place that have greatly increased the capability of the technology, one of which is blue lasers becoming more affordable. Blue lasers produce a thin scan line and generate a low amount of speckle, which reduces noise in the 3D data and improves resolution.


– Automation Technologies’ 3D cameras can generate more than 4,000 data points per line – that operate at higher speed. Klipfel said that inspecting larger PCBs, such as motherboards for computers, takes around 10 seconds using the company’s 3D sensor, whereas it takes two to four seconds to inspect smaller PCBs in mobile phones. Looking to the future, Klipfel


said Automation Technology is not only working on further increasing the speed of its 3D sensors, but also looking to take advantage of developments in illumination technology that will lead to better laser beam quality and straightness of laser lines used for 3D imaging.


@imveurope www.imveurope.com


inspecting a full phone display. However, the firm’s goal for the future is to reach a point where it can inspect multiple phones on one panel, according to Lewis. Te technology is still very


young. ‘Currently, it is more suited to the early stages of FPD development, where the OLED technology itself is still being worked on in R&D,’ Lewis said. Tere has been a lot of


angles and with certain lighting conditions, manufacturers can use TDI cameras to detect any impurities or defects present in the material. Te TDI cameras offered by Vieworks are able to achieve 18k and even 23k resolution with line rates up to 250kHz. ‘Vieworks TDI cameras use hybrid sensor


The lack of ability


interest in InZiv’s technology, according to Lewis, because the current yields in the OLED display market are very poor compared to LCD, which contributes to the high price tag associated with OLED technology. ‘Te lack of ability to identify the origin of many defects is leading to a lot of problems, in terms of yield in the [OLED] display market,’ he explained. ‘It is clear that existing inspection solutions today are not enough to effectively deal with the problem.’


to identify the origin of many defects is leading to a lot of problems in terms of yield in the [OLED] display market


technology, which means we use a CMOS chip structure integrated with a CCD on top, giving us the best of both worlds,’ Majewski said. ‘It combines the low signal-to-noise ratio and high dynamic range of the CCD – as well as the ability to move charge from one CCD line to another, to avoid additional noise – with the high readout speed of the CMOS.’ Te advances that have


taken place in polarised imaging over the past two years also show particular promise for the inspection


of glass in FPD production – stresses in the glass can be seen under polarised light. In 2018, Sony Semiconductor Solutions


Reflecting on glass inspection Glass inspection has its own difficulties, because it can be both transparent and highly reflective. However, when used at certain


released a CMOS sensor for imaging polarised light, which has since been integrated in cameras from a number of suppliers, including Teledyne Dalsa. Dr Xing-Fei He, senior product manager at Teledyne Dalsa, said that imaging polarised light could be used to improve the inspection capability of FPD production lines, particularly where glass is involved. He also pointed out that the technology isn’t yet fully developed: ‘Te technology is still very young


Teledyne Dalsa


Automation Technology


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