Standard structured light 3D solutions are available in two forms: (1) component, and (2) chip-level.
Component solutions are built on 3rd party camera and illumination products, user configured for a specific field of view. Chip-level integrated structured light solutions are built on custom electronics tightly integrated and mounted into a single mechanical design.
Both approaches provide similar functionality and performance once configured and set up. There are, however, a number of important differences that we will examine below.
Cost
Acquisition cost of component solutions is always higher, in part because 3rd party products each require final packaging, product certification and sales channel costs. In addition, they require multiple cables and connectors for communications and power distribution. Component solutions have a further hidden cost in how calibration can be achieved and maintained when there is no internal knowledge of how the optical systems are designed. As a result, frequent recalibration is required due to the effects of vibration, temperature change, and ambient light changes.
Chip level integrated solutions, on the other hand, have all their electronic assemblies rigidly mounted into a single housing design optimized for optical stability. Power distribution and internal connections are also fully optimized. The result is lower overall cost and superior optical performance. Furthermore, the best of today’s chip level integrated solutions are calibrated by the manufacturer, using specifically built precision automated systems, which eliminates the need for calibration by the user. Such designs are able to maintain calibration performance despite fluctuations in temperature.
Form Factor
Form factor is particularly critical when selecting sensors that will be built into complete measuring systems, and even more critical in selecting sensors for retrofitting into existing systems. Small form factors allow for easy mounting, minimizing costs to the integrator for system modification to allow seamless sensor installation.
Component solutions typically have a larger form factor because 3rd party modules feature independent packaging and cabling requirements.
Conversely, chip level integrated sensors achieve the smallest form factor possible, since the entire assembly is designed and optimized for a single package. The difference in form factors can be significant, making chip level sensors easier to integrate into inspection systems.
Sensor Packaging
Many applications for 3D sensors involve measurement and control in factory automation. In the factory environment, sensors are exposed to dust, dirt, vibration, moisture and temperature variation.
Most component solutions have the imaging lenses and projector completely exposed, use active cooling fans, and therefore will not survive long in factory environments. If component sensors are to withstand factory conditions, they require an environmental protective enclosure, which adds cost and increases size. Plus, flexible component mounting is often subject to movement due to vibration or temperature fluctuation, which alters the sensor geometry and results in inaccurate data.
In contrast, chip-level integrated solutions can achieve IP67-rated (dust and water resistant) packaging, and are ideally suited to the factory environment with no moving parts. Lenses and projectors are protected by flat, easily cleaned windows. These solutions have all their optical components mounted on a stable spine, making them immune to vibration and temperature drift.
Conclusions
Component level solutions have limited benefits –– namely the advantage of allowing the user to configure the field of view. In contrast, chip-level integrated solutions offer a number of advantages including lower cost, small form factor, and built-in protection against harsh factory environments.