Telecentric lenses with large fields of view (FOV) reduce measurement and inspection time in demanding metrology applications. Reducing measurement and inspection time provides faster product throughput and reduces cost.
As sensor technology advances and becomes more cost effective, pixel sizes are getting smaller and camera resolutions are increasing. In the past, 7-9µm pixel sizes were the standard; but today the standard pixel size is 3-5µm, with pixels as small as 1-2µm becoming more common. Previously, users were required to take an object offline for detail measurement and verification. But now that high resolution sensors are readily available and accessible, measurement and gauging systems have the image performance fidelity to measure and inspect the object online without interrupting operations. The lack of production interruptions allows for quicker inspection times, therefore decreasing the overall production time.
The majority of object sizes used in machine vision are between 50-200mm. With large FOV telecentric lenses, the whole object can be measured at once, online, without needing to re-position the lens or take the object offline, allowing for measurements to be made more quickly. The FOV of any telecentric lens is limited by the front optic diameter; the larger the required field of view, the larger the front optic diameter needs to be. As a result, large FOV telecentrics can be costly, making it even more important to consider the application and balance the performance, weight, size and cost requirements for all projects requiring large FOV telecentric lenses.