LINE CONFOCAL IMAGING TECHNOLOGY
Line Confocal Imaging technology, or LCI for short, is a technology for measuring microscopic-scale dimensions and tomographic structures.
Line Confocal Imaging technology in a nutshell
LCI technology is based on an optical method called lateral chromatic aberration where white light emitting from a sensor’s transmitter is split into a continuous spectrum of wavelengths. Each wavelength is focused on the measured surface at a certain distance from the sensor to form a perpendicular focal plane.
Key figures of Line Confocal Imaging technology
- Maximum repeatable resolution in Z (height): 0.11 μm
- Maximum Z range: 5.5mm
- Maximum measurement profile line length: 16.4 mm
- Amount of simultaneously measured points: 2048
- Maximum measurement speed: 5,000 lines per second (5kHz)
Line Confocal Imaging working principle
In the transmitter of a Line Confocal Sensor, there is a powerful white LED that functions as the light source. The light contains all the visible wavelengths and it goes through the illumination optics. The optics separate the light into different wavelengths and project horizontal lines of each wavelength at different heights onto the surface of the target.
The imaging optics in the receiver containing various optical elements such as slits and prisms, collect wavelength and intensity data from each horizontal line and transfer the data into the spectral camera. In the camera, CMOS arrays are formed based on the dominating wavelength and highest intensity information of each data point. The dominating wavelength reflected to the sensor’s receiver depends on the distance between the transmitter and each of the measured points.
The whole focal plane is reflected onto the receiver and the sensor analyzes thousands of measurement points at once. The 2D and 3D images are created based on the CMOS data in the software.
ORIGINS OF LCI TECHNOLOGY
In the late 2000’s, Karri Niemelä and I worked as scientists at VTT Technical Research Centre of Finland. We invented the LCI to overcome the problems of the existing technologies. In 2009, we met Sauli Törmälä and together we founded FocalSpec as a spin-off from VTT to further develop and commercialize Line Confocal Imaging as a high-speed optical technology that provides sub-micron resolution.
– Heimo Keränen, CSO –
Advantages of using LCI technology
- Analyses do not require any additional filtering: the imaging is based on the raw data, so what you see is what you measure
- Any color combination can be measured: matte or glossy, dark or light
- All surface types can be measured: mirror-like, glossy, transparent, translucent, curved, convex, concave, soft, fragile, porous
- Provides laboratory-level resolution and accuracy for high-speed imaging
Applications of LCI technology
Line Confocal Imaging technology is used for 3D topography, 3D tomography and 2D intensity imaging in demanding applications requiring sub-micron resolution and high measurement speed.
The most common applications of LCI technology are:
- Measurement of curved edge mobile phone displays
- Roughness analyses of transparent and non-transparent surfaces
- Defect detection on multilayer components
- Offset, step height, layer thickness, air gaps, clearance, distance, angle, area, volume, and coplanarity analyses in various industries
- Burr height analyses in the metal industry
- Seal integrity analyses of medical packages
- Various analyses in printed, hybrid, flexible, and organic electronics