Figure 1. View of the Novitech booth

At the Novitech booth, a banner was installed to introduce Novitech and Metrolab, as well as the s-Nova series of high-speed spectrometers, t-Nova series of optical thickness gauges, and s-Nova-H series of hyperspectral imaging spectrometers, and each product demonstration device was installed in front of them. On the left side, product catalogs and introductory videos were displayed to promote the products.

Figure 2. Two types of cover glass thickness profile measurements.

Figure 3. Coating film and cover glass thickness profile measurements

Figures 2 and 3 show a demonstration of the s-Nova-H series of hyperspectral imaging spectrometers, which made its debut at the exhibition. The wavelength band of the s-Nova-850H is 750 nm to 950 nm, the same as the s-Nova-850. The number of pixels on the wavelength axis is 1024, and the wavelength resolution is 0.2 nm. The number of channels on the spatial axis is 1280. This is equivalent to acquiring one sheet of spectral data using one s-Nova-850H, and simultaneously acquiring spectral data at each position using 1280 s-Nova-850 spectrometers. At a working distance of 75 mm, the maximum measurement length is 88 mm. As the working distance increases, the maximum measurement length also increases, and can be changed according to customer demand. The acquisition speed of the hyperspectral image is up to 42 Hz, and it can be acquired as an 8-bit image. Assuming a refractive index of 1.5, the s-Nova-850H can measure thicknesses ranging from 10 μm to 300 μm. Although demonstrated in a reflective configuration, the s-Nova-850H can also be used in a transmissive configuration, where the light source, measurement specimen, and hyperspectral imaging spectrometer are in a straight line.

Figure 4. The process of measuring a thickness profile using a hyperspectral imaging spectrometer.

Figure 5. Thickness profile measurement program screen using hyperspectral imaging spectroscopy

The process of thickness profile measurement using the s-Nova-H Series is shown in Figure 4. Use the s-Nova-850H on a measurement object moving in one direction to acquire a hyperspectral image perpendicular to the direction of movement, as shown in the left image in Figure 5. By analyzing the interference spectrum in each space by Fourier transform to calculate the thickness, the thickness profile of the line can be obtained as shown in the bottom right. When the workpiece is transported on a conveyor belt in a process, the thickness profile in two dimensions can be measured without any mechanical drive, such as a galvanometer. The measurement objects used in the demonstration were a coating film with a thickness of 20 μm and a cover glass with thicknesses of 90 μm and 100 μm, which demonstrated the measurement of the overall thickness profile.

Figure 6. s-Nova-850H illustration

In addition to the simultaneous measurement of thickness and refractive index with the t-Nova series and the measurement of thin films, many companies have been interested in the demonstration of thickness profile measurement with the s-Nova-850H.

Figure 7. s-Nova-H Series Project Representative