Telecentric lenses reduce the edge angles of both the incoming light rays and the image sensor, ensuring minimal distortion and superior image quality.
Unlike conventional lenses, where light rays diverge at different angles upon exiting, telecentric lenses keep all light rays parallel as they pass through. This unique feature sets them apart, as images captured with telecentric lenses demonstrate significantly enhanced precision and intricate detail compared to those taken with standard lenses.
The key to telecentric lenses' high precision lies in their construction. Telecentric lenses comprise two lenses with different focal lengths. The initial lens captures light from the object being imaged and then directs it to the second lens.
The second lens then projects the light to the device’s rear, especially the diaphragm. This diaphragm works as a control mechanism, controlling how much light enters the sensor. It ensures that only light rays aligned parallel to its surface can pass through.
This careful process produces highly accurate images, as it removes aberrations generated by off-axis rays—an achievement that standard lenses are unable to replicate.
Image Credit: Shanghai Optics
Image Credit: Shanghai Optics
Pros and Cons of Telecentric Lenses
There are numerous pros and cons when it comes to using telecentric lenses. The most significant advantage lies in the removal of parallax or perspective errors, while the downsides are principally linked to cost and size. Below is a breakdown of the advantages and disadvantages of telecentric lenses:
Advantages:
- Elimination of Parallax Error: Unlike traditional lenses, which present an angular field of view (AFOV), causing distant objects to appear smaller and closer ones to seem larger, telecentric lenses sustain a continuous field of view (FOV). This guarantees consistent magnification, irrespective of the object’s distance, leading to highly accurate measurements.
- Better Image Quality: Telecentric lenses produce image surfaces that are considerably undistorted and symmetrical, improving overall image quality.
Disadvantages:
- Elevated Costs: Telecentric lenses are usually more expensive than their traditional counterparts. Yet, this may not be a disadvantage if specific needs demand exclusive use of telecentric lenses.
- Potential Size and Bulk: In the case of object-space telecentric lenses designed to accommodate large objects, their size, and bulk can be a challenge when imaging substantial objects.
In fields where precise measurements rely on telecentricity, telecentric lenses are an absolute must. Their use is non-negotiable, making conversations about selecting traditional lenses over telecentric lenses irrelevant.
Use of Telecentric Lenses
The flexibility of telecentric lenses means that they find application in multiple industrial sectors, especially for automated processes. Telecentric lenses are particularly key in machine vision technology as they enable machines to observe and efficiently execute their designated tasks.
The reliability of telecentric lenses as mechanisms of guidance in machine vision processes, such as inspection and identification, highlights their importance. Numerous industries and fields benefit from the unique advantages these lenses provide, such as:
- Automotive components manufacturing
- Textiles production
- Solar power production
- Lithium-ion battery manufacturing
- Medical devices and equipment production
- 3C electronics manufacturing
- Optics
- Metrology
- Printing
- Pharmaceutical assembly and production
Telecentric lenses are invaluable for any task that demands precision, thanks to the unique capabilities they offer.
Telecentric Lenses: The Future of Precision
Achieved using appropriately placed apertures, telecentricity ensures a highly precise optical design. Telecentric lenses eliminate parallax errors and deliver the most accurate 2D representations of objects.
These lenses are categorized as object-space or image-space telecentric, depending on the aperture's location. Bi-telecentric lenses, featuring apertures at both ends, are especially popular in optics and metrology.
Although telecentric lenses may come at a higher cost, their unmatched precision makes them indispensable for applications where accuracy is critical. For industries, research, and professions that rely on machine vision, telecentric lenses are the go-to solution for achieving unparalleled precision.
Shanghai Optics’ expertise is in the provision of top-quality, custom-made telecentric lenses.
This information has been sourced, reviewed and adapted from materials provided by Shanghai Optics.
For more information on this source, please visit Shanghai Optics.