Hexagon Metrology, Inc.

Through-The-Lens-Laser (TTL)

The TTL laser and the image-processing vision sensor share the same optical path ("Through-The-Lens"). This coaxial principle allows seamless switching between camera and laser. As this concept does not involve an offset between the two sensors, no loss of measuring range in the X axis occurs and calibration is minimized.

As the rapid autofocus sensor, the TTL laser uses the laser light reflected from the surface of the inspected object to find the best focus position for the sensor. The distance to the inspected part's surface is determined by triangulating the reflected light. The TTL laser accelerates the focusing process when compared to conventional video focusing techniques, while achieving good reproducibility values. The result is an overall faster measuring speed.

The TTL laser can perform height measurements using a combination of focus points at different levels on the part. Scanning is another application of the TTL laser. With a high measuring point density of up to 350 points per second, the sensor is capable of capturing the profile of freeform surfaces in a non-contact and therefore non-destructive manner.

Example applications for the TTL laser:

  • Quick focusing of the vision sensor
  • Precise measurements of heights, hole depths and flat surfaces
  • Contour and surface scanning


Technical Characteristics
Measuring Principles Foucault
Magnification Starting from 5x lens
Recommended starting from 10x lens
Laser Safety class 2
Average output <1 mW
wavelength 650 nm to 680 nm
Resolution ±0.1 µm
Average Focus Speed 0.2 s