LCI in cell phone manufac­turing

Benefits of the linear confocal imaging (LCI) in cell phone manufacturing.

FocalSpec Line Confocal Scanner use cases and examples

The purpose of this document is to briefly describe verified uses cases for Line Confocal Scanner in the mobile phone manufacturing. Other electronics industry applicable systems utilizing the same optical imaging technology include:

  • MicroProfiler MP 400 for printed electronics industry and
  • MicroProfiler MP 900 for cable manufacturing

1 Line confocal imaging

1.1 Working principle

Line confocal imaging is a non-contact optical measurement method. Visible spectrum of light is focused on different vertical distances and an accurate topographic surface profile is measured by using the spectral analysis of reflected light. In LCI applications, the light source and the imaging spectrometer form one robust, fast and easy-to-integrate measurement head. The technology works even on the most challenging sample shapes and surface materials.

1.2 FocalSpec Line Confocal Scanner

Line Confocal Scanner helps you to analyze and control:

  • 3D-AOI
  • Non-contact 3D inspection
  • Clearances, offsets and gaps
  • FA testing
  • DFM
  • Surface appearance and characteristics / Look & feel
  • Microtopography
  • Tomography
  • Thickness
  • Burr
  • Flatness

The Scanner can be used as a stand-alone measuring instrument or as an integrated component of production/assembly processes functioning as an at-line quality inspection station.

Once the system is started up, the product specific “recipe” is selected from the database. The product(s) to be scanned are placed, either manually or automatically, in an inlet that is mounted on the scanner’s high-resolution XYZ stage. The scan is initiated and the stage is automatically moved under the system’s internal optical LCI sensor following an optimized path.

After the scan is completed, the results are displayed on the scanner’s touchscreen monitor and saved in the database. The ultra-high resolution point cloud resulting from the scan offers practically unlimited analysis options. The measurement time depends on the size of the scanned area, selected Y stage motion resolution and the system’s sensor model.

1.3 Benefits and limitations in industrial applications

Line Confocal Scanner offers you laboratory level accuracy for the most demanding at-line industrial applications. The Scanner measures five million 3D points per second with the highest accuracy and repeatability available on the market.

Dark matte, glossy and transparent samples can be inspected. The tilting tolerance for angled, glossy samples is the largest available in the market. There is no speckle noise nor interference and a submicron measurement accuracy is guaranteed be the sample moving or not.

No data filtering is needed for accurate end results. The automated optical testing procedure is free of any physical contact.

2 LCI utilization in cell phone manufacturing process

2.1 Concept and prototyping

All cell phone manufacturer’s start the process in the conceptual phase. Several sketches and wireframes are created using different designs, features, and interface options, such as keypad only and touchscreen (Picture 1).

puhelin_10032016Picture 1: Cell phone prototyping

These sketches also determine the phone’s weight, scale, size and portability. Because the goal of most phones is to be compact and portable, this phase is the most intensive. During this process, a team decides what designs will become prototypes. Once a list is determined, several prototypes are created. These models are usually non-functional and only for visual purposes. Prototypes are constructed from plastic, Styrofoam and other re-usable materials. Once a final design is created, the concept is pushed to engineers, who decide what electronics are necessary.

The Scanner can be used to adjust the smallest components to the thinnest prototypes and thus to make better evaluation of the prototype’s manufacturability.

2.2 Parts and software

The key part of every mobile phone is its electronics. The electronics control everything from the way the phone displays information, places calls, sends location information and more. Depending on the features determined during the conceptual phase, different electronics can be used. For most cell phones, there are three key components: a printed circuit that controls the keypad and signal reception, a battery, and screen. A separate application note “Control of Printed Electronics” highlights the benefits of LCI in printed electronics manufacturing (Picture 2)  and introduces FocalSpec MicroProfiler MP400, a printed electronics industry specific, plug and play non-contact QA system provided by FocalSpec.

printattu_elektroniikka_10032016Picture 2: LCI can also be put to use in printed electronics QA. See FocalSpec application note on “Control of Printed Electronics”.

In addition to the hardware, software is also required for the phone to operate. Almost all mobile phone manufacturer’s use proprietary software for their phones. The software is designed by a series of programmers that develop the design of the interface, the phone’s basic/advanced operations, and other features. By default, most modern mobile phones are programmed with basic features like text messaging, calendar and clock. After these components and software are determined, the phone moves on to final construction.

2.3 Construction and fabrication

Each piece of the mobile phone is created separately. First, the casing for the phone is made. Most cell phones use a simple plastic that is created using a process known as injection molding. Once the casing is created, the printed circuit board is made and loaded with the necessary software/operating system. The circuit board is then placed in the casing, using a series of eyeglass screws. Next, the other components of the phone are added: screen, keypad, antenna, microphone and speaker. The tolerances, gaps and offsets can effectively be controlled with the help of Line Confocal Scanner (Picture 3).

painike_10032016Picture 3: Gaps, offsets and tolerances can be effectively controlled with Line Confocal Scanner

After the phone is constructed, it is moved on to testing. During the testing phase, the battery for the phone is added and a worker checks the phone for power, button functionality and reception. The Scanner can be used not only to verify the component construction, but also to test button functionality.

Finally, the necessary documentation for the phone is produced and sent to be packaged with the phone. Once all of these components are verified, the phone is packaged and shipped to retail outlets.

3 Summary and key findings

Line Confocal Scanner utilizes new LCI imaging technology that can be used in cell phone manufacturing for tasks that lasers and CMMs do not perform well on

  • sloped, angled, curved, rounded, convex and concave,
  • glossy, glassy, reflective and mirrorlike,
  • transparent, semitransparent and opaque,
  • high contrast (light/dark or glossy/matte),
  • delicate, elastic and soft


The scanner can be utilized throughout the cell phone lifecycle from research & development to manufacturing process optimization and quality control to effectively measure and analyze:

  • High precision 3D dimensions
  • Assembly tolerances
  • Clearances, gaps and offsets
  • Flatness
  • Surface appearance/characteristics
  • Look & feel
  • Roughness and burr
  • Thickness of transparent / semitransparent parts.

In addition to cell phone manufacturing, line confocal imaging technology can also be utilized in printed electronics industry (MicroProfiler SQM) and cable manufacturing (MicroProfiler MP 900). FocalSpec Line Confocal Sensors (LCI 400, LCI 1200 and LCI 1600) are utilized by integrators in tailored QA solutions.

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