Telecentric Lenses – Precision Optics for Accurate Measurement

Telecentric lenses are specialty optical systems designed to maintain a constant magnification regardless of object distance. This unique property makes them indispensable for machine vision, metrology, inspection, image sensor testing and projection systems where dimensional accuracy, long working distance and low distortion are critical. At Yighen Ultra Precision, we supply a wide range of telecentric lenses—object‑space telecentric, image‑space telecentric and bi‑telecentric—tailored to your sensor format and measurement requirements. Our pre‑engineered designs can be quickly optimised to your application, saving you development time and cost, while fully custom solutions are available for more specialised needs.

🔍 What Is a Telecentric Lens?

Telecentric lenses are designed so that chief rays are parallel to the optical axis in the object space, image space, or both. This telecentricity means magnification remains constant across the entire field of view, even when the object position varies within the depth of focus.

• Object‑space telecentric lenses have the entrance pupil at infinity, ensuring parallel chief rays on the object side. Magnification is independent of object distance and position, making them ideal for conveyor‑belt inspection and robotic alignment.

• Image‑space telecentric lenses place the exit pupil at infinity, keeping chief rays parallel on the sensor side. This minimises pixel shift when changing focus and is particularly useful in dimensioning systems where sensor position may vary.

• Bi‑telecentric (double telecentric) lenses are telecentric in both object and image space. They provide the highest accuracy and minimal parallax, maintaining constant magnification regardless of object distance or sensor position—perfect for precision measurement and high‑speed inspection.

Unlike conventional lenses with an angular field of view (where magnification decreases as object distance increases, causing perspective error), telecentric lenses offer a non‑angular, constant field of view. This eliminates parallax and ensures that measurements remain accurate without complex software calibrations. Additionally, any blur that occurs is symmetrical about the focus plane, so the centroid of features remains stable even if they are slightly out of focus.

🧪 Key Features & Optical Performance

In addition to constant magnification and low distortion, Yighen’s telecentric lenses incorporate several advantages inspired by industry leaders:

• Long working distance – Maintain accurate measurements even when the object is far from the lens, accommodating large components or recessed objects in industrial environments.

• Large image size capability – Capture large objects in a single frame without sacrificing measurement accuracy.

• Low distortion – Distortion values are typically below 0.1%, reducing or eliminating the need for post‑processing calibration and lowering CPU load in measurement software.

• Rugged housings and modular mounts – Engineered for factory environments, our lenses come with robust barrels and optional custom mounts and coatings.

• In‑house manufacturing and detailed test reports – All lenses are produced and tested in our own facilities, ensuring consistent quality and supplying a detailed test report for each lens.

🛠️ Custom Design & Applications

Yighen’s optical engineers can customise telecentric lenses to meet the specific requirements of your inspection or measurement system. We adjust parameters such as magnification, numerical aperture, working distance, field of view and wavelength range to match your camera sensor and the size of the objects being measured. Pre‑engineered preliminary designs can be quickly tuned to your dimensions and wavelength needs, saving you from designing from scratch and helping reduce or eliminate design fees.

Key application areas:

• Dimensional measurement of mechanical parts, PCBs and semiconductors

• Metrology and coordinate measuring systems (CMM)

• Machine vision inspection in factory automation

• Precision assembly alignment for electronics and robotics

• Image sensor testing and laboratory optical setups

• Laser triangulation and 3D scanning modules

🧰 Why Choose Yighen?

• High performance and value – Excellent price‑to‑performance ratio without compromising quality.

• Customisation & flexibility – From stock lenses to fully custom designs, with optional custom lens mounts and coating.

• Rugged and reliable – Durable housings designed for harsh environments; long working distance and large image size capabilities.

• In‑house manufacturing – All lenses are made in our own factories, ensuring unmatched quality and providing detailed test reports for each lens.

• Expert support – Our engineers optimise preliminary designs to your exact needs, saving time and design fees.

🧪 Sample Specification – 2× Bi‑Telecentric Lens for Machine Vision

❓ Frequently Asked Questions

Q: Why is constant magnification important for measurement?
In measurement applications, perspective error can cause the apparent size of an object to change with distance. Telecentric lenses eliminate this error by maintaining parallel chief rays and constant magnification, ensuring consistent measurement results even when objects move within the field of view.

Q: How do telecentric lenses differ from conventional lenses?
Conventional lenses have an angular field of view that causes magnification to change with distance, leading to parallax and calibration errors. Telecentric lenses feature a non‑angular field of view, so magnification remains constant. They also have lower distortion, symmetrical blur and longer working distances, making them ideal for machine vision and metrology.

Q: Do telecentric lenses inherently have a larger depth of field?
Not inherently. However, because the blur is symmetrical around the focal plane, the centre of mass of features (e.g., corners) remains stable, allowing accurate measurement even if the feature is slightly out of focus.

Q: Can you provide custom mounts, coatings or environmental sealing?
Yes. We offer custom lens mounts to fit your system and optional coatings for specific wavelength ranges (e.g., NIR or SWIR). Ruggedised housings with sealing or protective windows can be provided for harsh environments.

🎯 Telecentric Lens Design for Precision Inspection and Dimensional Accuracy

Yighen offers high-performance telecentric lenses for industrial vision, laser triangulation, and measurement systems where minimal perspective error is critical.

📩 Request a Custom Telecentric Lens
We customize magnification, working distance, and sensor format to match your exact metrology needs.

📘 Need technical specs or drawings?
Visit our Downloads page to access detailed datasheets and mechanical models.

🏢 About Yighen
Learn how we combine ultra-precision machining and optical simulation at About Us.

🔗 Related Content

• 🔬 Microscope Objectives
  Explore other high-precision optics for measurement and biomedical imaging.

• 🧩 Opto-Mechanical Modules
  Integration-ready assemblies with lens mounts, barrels, and alignment fixtures.

• 📏 Optical Tolerancing & Simulation
  Enhance accuracy with Monte Carlo simulation and mechanical tolerance analysis.

• 🧠 Optical Engineering Services
  Modeling, optimization, and system-level co-design support.

• 🎥 Zoom Lenses
  Compare with flexible focal length modules when telecentricity is not required.