Telecentricillumination

Telecentric lenses have two types of telecentricity: object space and image space telecentricity (referring to the entrance and exit pupil positions, respectively). Therefore, telecentric lenses are divided into: object space telecentric lens, image space telecentric lens, and bi telecentric lens.

Resolution is the ability to resolve details in the object. It describes the thinnest line that the human eye can distinguish. Normally, the resolution for machine vision telecentric lens image is as below:

Telecentriclens

Telecentric Lens has a very low level of distortion, which makes the telecentric lens an excellent choice for metrology applications

The DOF of a telecentric lens can be changed by adjusting its aperature. When the aperature gets bigger, the DOF becomes smaller. When the aperature gets smaller, the DOF will increase.

Telecentriclens design

An object space telecentric lens in which the chief ray is completely parallel to the optical axis in the object space. Note that the field of view does not change no matter where the object plane is, because the chief ray that defines the field of view is perfectly parallel to the optical axis.

In general, a machine vision telecentric lens refers to an object space telecentric lens. If the entrance pupil of the lens is located at an infinite position in the image side (all objects behind the objective lens), it can be called an object space telecentric lens. The chief ray originated from optical axis is parallel with optical axis in object side ( or to say have very small angle θ which is called telecentricity in telecentric lens specs), while in image side is not parallel.

Bi-telecentric lenses are the most accurate type of telecentric lenses because their field of view is completely unaffected by changes caused by changes in object position or sensor position, nor does it operate any cos4θ attenuation. The diagram below shows the comparison of three different lenses: fixed focal length lens,  object space telecentric lens, and double-telecentric lens. The X-axis represents the change in working distance (mm) from the nominal value, and the Y-axis represents the dimensional error percentage from the actual value.

Thorlabstelecentriclens

Suitable for line scan cameras such as 16K x 5μm,16K x 3.5μm,12K x 5μm, 8K x 7μm, etc, and area scan camera such as 155 mega pixels, 151 mega pixels

The chief ray originated from optical axis has a angle θ with optical axis. For objects at different WD from the lens, the lens will have either smaller or larger mag.

As you can see, the bi -telecentric lens is the most accurate lens in the group, with a working distance offset of 4mm and an error of less than 0.2% during this period. Bi-telecentric lenses should be used in applications that require the highest accuracy and precision.

TelecentricLens cost

Resolution formula is R=0.61*λ/NA. R is object resolution and λ is wavelength, which is usually 0.55um. NA is the numerical aperture of the object side of the lens.

A Telecentric lens is a kind of lens that the chief rays are parallel to the optical axis. There are three kinds of telecentric lens, that is the object-space telecentric lens, image-space telecentric lens, and the bi-telecentric lens. Telecentric lens is always the core business of Canrill Lens. After continuous research and development for 11 years, Canrill has successfully developed 1700+ kinds of lenses, and the number is still increasing, to meet the diverse and growing applications at the best telecentric lens price.

Telecentriczoom lens

Yes, we can customize lens based on customers’ request. As long as customer provides us with necessary optical requirement, we will be able to customize the lens in a very quick time.

Opto lens

Telecentric Lens system can have a larger depth of field, which is beneficial in maintaining a very good image contrast even when looking at very thick objects

For example, XF-MT1X65D, the NA is 0.045, thus the resolution is 0.61*0.55/0.045≈7.45um. ( the resolution in our product list and drawings is 7.33um, is because decimal point numbers )

MTF is Contrast of output image/Contrast of input image. Since the input image is always larger than the output image, therefore the MTF value is always from 0-1.

The machine vision telecentric lens design is mainly to correct traditional industrial lens parallax. Within a certain range, a telecentric lens for machine vision can make the image magnification of the image does not change. Currently, due to its unique parallel optical path design, the telecentric lens has been widely favored by machine vision applications that are highly required for lens distortion.

Telecentricscan lens

Telecentric Lens can eliminate the parallax error characteristic by having a constant, non-angular field of view. Its magnification and field of view do not change at any distance from the object

Although object space telecentric lenses can provide much higher measurement accuracy than conventional lenses, bi telecentric lenses can also achieve higher accuracy if the lens is object and image space telecentric. The principle of image space and object space telecentricity also applies in bi telecentric lenses. In a bi-telecentric lens, the entrance and exit pupils project to their respective infinity. The chief ray originated from optical axis is parallel with optical axis in both object side and image side ( or to say have very small angle θ which is called telecentricity in telecentric lens specs).

High mag from 1.5X to 4X, object telecentric design, coaxial type for option, high resolution with good consistency, suitable for high precision semiconductor & display board inspection

In the optical design, object space telecentricity is achieved by placing the system's iris diaphragm at the intersection of the front-end groups. Since the entrance pupil is at infinity, the field of view is constant and has no field angle. Since the chief ray (which defines the system's field of view) passes through the optical axis at the aperture stop, when the pupil is at infinity, the ray is parallel to the optical axis and the field of view is zero. By contrast, any entrance pupil within a finite distance of the lens results in a non-parallel fiber.

High mag from 1X to 4X, bi-telecentric design, working distance from 65mm to 178mm. Built-in coaxial illumination is available.

Canrill has mainly two types of telecentric lens for sale: bi telecentric lens and object space telecentric lens. For your selection more quicker, we sorted out different types of telecentric lens. If you have any questions on buying telecentric lens, welcome to inquiry us. We are gladly to offer answers,