Figure 1. t-Nova-850H, a three-dimensional surface topography measurement sensor, on display at the booth.

Highly-functional Material Week was held at Makuhari Messe, Tokyo, Japan, from Wednesday, October 4 to Friday, October 6. At Novitec's booth in the Photonix section, the t-Nova-850H, a three-dimensional surface topography measurement sensor using line spectroscopy developed by Metrolab, as shown in Figure 1, was introduced to the world for the first time. At the exhibition, the sensor measured the surface topography of the entire area of a single-stage standardized material with varying heights in real time. With only one directional scanning, the three-dimensional surface topography of the entire area of the object was measured and demonstrated.

Figure 2. Measurement process of unidirectional scanning three-dimensional surface geometry using t-Nova-H.

Figure 3. (a) Hyperspectral image acquired with the t-Nova-850H, (b) acquired profile.

The t-Nova-H uses the s-Nova-H, a hyperspectral imaging spectrometer developed by Meterlab, as its sensor. The s-Nova-H was introduced at Photonix 2022 last year as a line measurement sensor for glass and film thickness measurement. Figure 2 illustrates the process of surface topography measurement with the t-Nova-H. By measuring a line on an object with a stepped pattern with the t-Nova-H, a hyperspectral image of each point on the line can be obtained as shown in Figure 3(a). By Fourier transforming the interference pattern along each spatial axis to calculate the distance, the line surface profile is finally obtained, as shown in Figure 3(b). To obtain a three-dimensional surface topography of the entire region, the specimen only needs to be scanned in one direction.

Figure 4. (a) Measurement specimen (KRISS single-phase certified standard material), (b) Three-dimensional surface geometry measurement results of the specimen

To demonstrate the t-Nova-850H, we measured the surface topography of a single-order certified standard material purchased from KRISS as shown in Figure 4(a). The direction of the first line measurement was horizontal to the specimen, and the scanning direction was scanned along the surface from the top to the bottom of the specimen. At each position, the line surface profile was measured and plotted on the three-dimensional spatial axis to obtain the three-dimensional surface topography as shown in Figure 4(b).

Figure 5. t-Nova-850H explained

In addition to the simultaneous measurement of thickness, refractive index, and thickness of thin films using the t-Nova series, many companies were interested in the s-Nova series of high-speed spectrometers, and the demonstration of three-dimensional surface topography profile measurement using the t-Nova-850H, which was introduced for the first time this year. The use of the t-Nova-H sensor in a roll to roll process is expected to enable the measurement of the surface topography of the entire area of the workpiece without mechanical drive of the measuring sensor, enabling quality control of the entire production area.