Device and method for confocal measurement of surface type or thickness through spectrum black hole

Abstract

The invention discloses a device and a method for confocal measurement of a surface type or thickness through a spectrum black hole. An optical system composed of a multispectral light source, a first focusing lens group, a light-transmitting reflector, a collimating lens group, a dispersion focusing lens group, an XY displacement platform, a second focusing lens group and an optical signal processing assembly is scientifically and reasonably designed. Or an optical system formed by a multispectral light source, a Y-shaped optical fiber, an optical signal processing assembly, a collimating lens group, a dispersion focusing lens group and an XY displacement platform can obtain part of defocused light around a confocal focus in the optical system; further, the optical signal processing assembly obtains a spectral signal with a wave crest with a certain width and a sharp wave trough clamped in the middle, processing and multiple times of calculation are carried out according to the wave trough in the obtained spectral signal and wave crest value data on the two sides, and according to the calculated value and the displacement relation of the detected panel in unit time, the surface type or the thickness of the detected panel can be efficiently and accurately calculated in a non-contact manner.

Description

【Technical field】 [0001] The invention relates to the field of cutting-edge optical detection, in particular to a device and method for confocally measuring the surface shape or thickness of a spectral black hole. 【Background technique】 [0002] With the development of the industry, the advancement of technology and the improvement of craftsmanship, many manufacturers of transparent panels such as mobile phones have an increasing demand for the measurement of the surface shape and thickness of the panel, and require higher and higher precision. Taking the production of mobile phone panels as an example, the design is getting thinner and thinner. For straight-screen transparent panels, the flatness requirements should be met, and some curved transparent panels should meet the curved surface requirements, and at the same time, high measurement efficiency should be ensured. Other industries that require transparent panels also have a huge demand for precision measurement, and t...

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Problems solved by technology

[0003] At present, the most widely used measurement method in China is contact measurement. This measurement method is slow and easy to scratch the panel under test or leave fingerprints or foreign objects on it.

For domestic non-contact optical measurement sensors, there are still problems such as limited types, limited application, high cost and insufficient accuracy, and high-end non-contact optical measurement sensors are mainly designed and produced by foreign countries, and the cost of import and purchase is very high

[0004] For the common confocal spectrum detection method, the sharp peak signal is obtained on the spectrum for analysis. In order to improve the measurement accuracy in the existing confocal spectrum system, the smaller the light spot, the better. Because of the need for a wide-spectrum light source, it is usually as small as possible. The size of the small hole or fiber, after reducing the size, the obtained light spot effect will be better, the obtained spectral peak signal will be sharper, and the measurement signal will approach a single measured confocal focus wavelength, so as to obtain a more accurate measurement value. But this will make it more difficult for the light to be coupled to the optical fiber or the light energy will be much weaker after the light source passes through the small hole, resulting in weaker light signals reflected by the surface of the tested panel. It is difficult to improve the resolution by using this detection method will continue to increase, and the cost of production and design will also increase

Moreover, after obtaining a sharp peak signal, there is also a problem that the peak width is smaller than the resolution sampling interval, and the measurement accuracy will also decrease at this time.

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