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Product category: Electronics Manufacturing Machinery and Materials
News Release from: AccuPlace | Subject: APAC
Edited by the Electronicstalk Editorial Team on 20 October 2005

Placement platform takes optics onboard

AccuPlace has come up with an automated solution for integrating glass lenses with antisplinter films into modern handheld electronic devices

Today's consumers demand more from their handheld electronic devices than ever before, and this trend shows no sign of slowing. As the display is the primary point of focus for the consumer in a mobile phone, many devices now use glass lenses to improve the user experience compared with that offered by traditional polycarbonate lenses.

Benefits include improved optics, decoration possibilities, and smaller thickness.

Although glass offers many benefits to the user, design engineer and mobile device manufacturer, it presents a unique challenge.

It can shatter and expose the user to dangerous glass fragments.

One methodology for meeting this challenge has been the development of antisplinter films (ASF) to cover the glass and protect users.

This component consists of optically clear adhesive and a transparent film.

The test for machine builders was to develop processes that place the film so it is unnoticeable to the consumer.

This requires extremely accurate placement, contaminant free assembly, and elimination of all entrapped air.

To meet this unique combination of requirements AccuPlace has turned to its APAC platform.

The APAC is an innovative, fast pick-and-place cell that blends a high performance robot with adhesive component feeders.

Required assembly tolerances of +/-0.025mm mandate the use of the APAC's standard vision option for positional recognition of the anti-splinter film and lens prior to placement.

Contaminants also present an obstacle as any particulate between the film and the lens would result in quality rejection at the inspection station.

The APAC employed clean room class 10 RM2065 units for feeding the anti-splinter films.

These feeders employ AccuPlace's patented peeling technology along with numerous other features to ensure clean room compatibility.

To further ensure the cleanliness of the process, all assembly takes place in an isolated 'clean' environment inside the assembly cell.

All air exhaust ports are plumbed together for transmission to an outside vacuum system.

Although placement accuracy and contaminant elimination each presented their own challenges, the greatest engineering attention was required to eliminate air entrapment after placement of the film.

The lenses themselves are loaded into the cell on plastic trays.

The lens is processed by removing one from the tray, loading it into an ultrasonic fixture, assembling the ASF, and subsequently returning it to the tray.

The task of bubble-free placement is a multistep process using AccuPlace Ultrasonic Squeegee Evolution technology (patent applied for).

The procedure evolves from the Maxi, to the Micro and subsequently the Nano squeegee to remove even the most microscopic bubbles.

The Maxi squeegee is embedded in the servo end effector of the APAC machine.

The Maxi effectively picks up the anti-splinter film from the RM2065 as it is peeled.

The end effector transports the film to lens where it is assembled by touching the film to one edge of the glass and subsequently wiping across the lens.

It is imperative that the film be wiped in controlled and consistent methods otherwise large bubbles can become entrapped which are very difficult to remove later.

As well many lenses have printing causing uneven surfaces whose profiles must be mimicked exactly by the APAC end effector.

Air coupled tooling to change between the three squeegee types and optional vision inspection for bubbles are other features that allow the APAC to complete this task with ease.

After initial placement most lenses require secondary squeegee operations to remove even the smallest of bubbles.

The machine next uses the micro and then the nano to drastically increase the effective squeegee force while the ultrasonic nest is activated enhancing entrapped air removal.

While sounding rather complex, the process is actually very simple and results in an optically clear assembly.

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