A Phase Plate for Phase Contrast Microscopy

Abstract

The invention relates to a phase plate for a phase contrast microscope. According to the phase plate, a glass substrate (1) is coated with an annular thin film layer (2); the annular thin film layer comprises a bottom layer (5) directly coating the glass substrate (1), an interlayer (6) and a surface layer (7); the interlayer (6) is a MgF2 layer; the bottom layer (5) and the surface layer (7) are metal film layers made of the same material; and the material of the metal film layers is one material selected from Cr, Nb, Ti and Ni. The phase plate has a plurality of functions such as a phase changing function and a light beam absorption function. The wide-band phase change of the phase plate is small, so that the phase value of a wide-band light beam of which the wavelength ranges from 450 nm to 700 nm can be about -90 degrees, wherein the wide-band light beam passes through the phase plate, and therefore, the phase plate can be used under wide-band light sources; and the phase plate is simple in film layer structure and is convenient to manufacture.

Description

technical field [0001] The invention relates to a phase plate for a phase contrast microscope, especially a phase absorption film of the phase plate. Background technique [0002] The human eye can only identify changes in the wavelength (color) and amplitude of visible light, but not phase changes. However, most biological specimens are highly transparent, and the amplitude of the light wave is basically unchanged after passing through, but there is a phase change, which cannot be felt by the human eye. Living cell samples and unstained specimens cannot be directly observed by the human eye because the wavelength and amplitude of light do not change, but the phase of the light passing through the sample has changed, so the interference and diffraction effects of light can be used to distinguish the difference between the passing samples. The optical path difference of the light at the site is converted into a difference in amplitude, enabling clear visualization between va...

AI Technical Summary

Problems solved by technology

Although a single layer of MgF2 can change the phase (such as a negative phase process), the single layer of MgF2 film can only form a phase difference of -1 / 4λ at a specific wavelength, which is not suitable for broadband light sources. When using broadband light sources, the contrast ratio will decrease Therefore, a monochromatic filter of a specific wavelength must be added in front of the light source; however, the introduction of the filter will inevitably lead to the loss of light source energy, resulting in a dim field of view

In addition, the phase absorbing film of the traditional phase plate has a ring-shaped junction with a height difference between the single-layer MgF2 film and the single-layer Cr12 film. It is difficult to guarantee the coating accuracy at the ring-shaped junction, resulting in a long production process and low yield , which limits the processing efficiency and makes the manufacturing cost higher

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