Glass optical slit structure integrated with filtering function

Abstract

The utility model discloses a glass optical slit structure integrated with a filtering function, which comprises a substrate, two sides of the substrate are respectively provided with a coating layer and an isolation layer, the outer side of the isolation layer is provided with a metal coating, the material of the substrate is one of quartz, glass, zinc selenide and germanium, the isolation layer is formed by plating silver on the surface of the substrate, and the metal coating is coated on the surface of the substrate. The metal coating is generated by black chromium on the surface of the isolation layer, the film coating layer is generated in a vacuum evaporation or ion sputtering mode, and a blank area is reserved to form a slit when the isolation layer and the metal coating are plated on the surface of the substrate. According to the utility model, functions of a traditional slit and an optical filter are integrated, miniaturization of parts is facilitated, and installation is convenient; laser processing of a stainless steel sheet is changed into substrate plating of a metal film, so that the processing error is reduced; the slit is generated in an electroplating blank leaving mode, the shape of the slit can be made into a quadratic curve shape besides a straight line, aberration is reduced, the channel effect is greatly reduced, stray light is reduced, and cost is greatly reduced.

Description

Technical Field

[0001] This utility model relates to the field of precision optical element technology, specifically to a glass optical slit structure with integrated filtering function. Background Technology

[0002] The slit is one of the most common components in spectrometer equipment. It is generally made of stainless steel sheet, with a thickness of 0.1–0.5 mm, a slit width of 10–100 μm, and a slit length of approximately 0.2–3 mm. Its problems include high cost (several hundred yuan), poor accuracy (error within a few micrometers), and significant channeling effect. Filters are also an essential component of a spectrometer, used to filter out unwanted stray light. They are often used in conjunction with optical slits at the entrance or exit slits, and suffer from inconvenient installation and high cost.

[0003] The structural principle of a typical spectrometer is as follows: Figure 1 As shown, where: SL is the entrance slit, F1 is the high-pass filter, L1 is the collimating lens, L2 is the converging lens (L1 and L2 can also be replaced by concave mirrors), PG is the beam splitter grating, and AD1 is the array detector.

[0004] Two key technical indicators of a spectrometer are spectral resolution and stray light.

[0005] Spectral resolution represents the spectrometer's ability to resolve spectral lines, while stray light represents the spectrometer's sensitivity. Generally speaking, the smaller the stray light, the higher the spectrometer's sensitivity.

[0006] Spectral resolution = Δλ1 + Δλ2 + Δλ3

[0007] Where: Δλ1 is the spectral broadening of the incident slit; Δλ2 is the grating diffraction broadening; Δλ3 is the spectral broadening of the incident slit image.

[0008] Δλ2 is related to the characteristics of the grating itself and the focal length; while Δλ1 and Δλ3 are both related to the width of the entrance slit.

[0009]

[0010] Where: a is the width of the entrance slit; a' is the width of the image in the entrance slit; f is the focal length of the collimating lens; This represents the dispersion coefficient. Therefore, it is evident that the spectral resolution of the spectrometer is closely related to the width of the entrance slit.

[0011] The width and straightness of the entrance slit mainly affect the spectral resolution of the spectrometer, while the thickness and smoothness of the slit mainly affect the stray light of the spectrometer.

[0012] If the slit edge is thick and rough, incident light will be scattered at the slit edge, forming stray light, a phenomenon commonly known in optics as the "channel effect." Since the incident light source cannot be perfectly parallel, the thicker the slit, the greater the probability that the incident light will hit the side walls of the slit. This causes diffuse reflection at the side walls, changing the incident direction of the light, which then enters the detector through mirrors and other optical systems, forming stray light. Figure 2 As shown.

[0013] The slit width is typically around 10µm to 100µm, while the precision of typical laser processing is around 2µm to 5µm. Machining slits on stainless steel results in uneven edges and numerous burrs, leading to poor consistency in spectral resolution. Furthermore, having two separate components—the slit and the high-pass filter—results in a larger size and makes installation and adjustment inconvenient. Utility Model Content

[0014] The purpose of this invention is to provide a glass optical slit structure with integrated light filtering function to solve the problems mentioned in the background art.

[0015] To achieve the above objectives, this utility model provides the following technical solution: a glass optical slit structure with integrated filtering function, comprising a substrate, a coating layer and an isolation layer respectively disposed on both sides of the substrate, and a metal coating disposed on the outer side of the isolation layer. The substrate is made of one of quartz, glass, zinc selenide, and germanium. The isolation layer is formed by silver plating on the surface of the substrate, and the metal coating is formed by black chromium plating on the surface of the isolation layer. The coating layer is formed by vacuum evaporation or ion sputtering. When plating the isolation layer and the metal coating on the substrate surface, a blank area is reserved to form a slit.

[0016] Preferably, the thickness of the metal coating is 300 nm.

[0017] Compared with the prior art, the beneficial effects of this utility model are: this utility model integrates the functions of traditional slits and filters, which is conducive to the miniaturization of parts and easy installation; the slit edges are smooth and thin, there is no channel effect and very little stray light, which is conducive to improving the sensitivity of the spectrometer. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the existing spectrometer structure.

[0019] Figure 2 A schematic diagram illustrating the channel effect;

[0020] Figure 3 This is a schematic diagram of the structure of this utility model.

[0021] In the diagram: 1. Substrate; 2. Coating layer; 3. Isolation layer; 4. Slit; 5. Metal coating. Detailed Implementation

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0023] Please see Figure 3 This utility model provides a technical solution: a glass optical slit structure with integrated light filtering function, including a substrate 1, with a coating layer 2 and an insulating layer 3 respectively disposed on both sides of the substrate 1. The coating layer 2 is used to achieve the light filtering function, and a metal coating 5 is disposed on the outer side of the insulating layer 3. The substrate 1 is made of one of quartz, glass, zinc selenide, and germanium. The choice of substrate material is related to the wavelength. Quartz is generally chosen in the ultraviolet region; quartz and glass can be chosen in the visible and near-infrared regions; and zinc selenide and germanium can generally be chosen in the mid-infrared region.

[0024] The insulating layer 3 is formed by silver plating on the surface of the substrate 1, and the metal coating 5 is formed by black chromium plating on the surface of the insulating layer 3. The thickness of the metal coating 5 is 300 nm. The coating layer 2 is formed by vacuum evaporation or ion sputtering and is composed of a multilayer dielectric film structure. By controlling the thickness of different dielectric films, the spectrum of incident light can be modulated, for example, to form a high-pass filter or a narrow-band filter. When depositing the insulating layer 3 and the metal coating 5 on the surface of the substrate 1, a blank area is reserved to form a slit 4. Therefore, the shape design of the slit can be more flexible and free. The slit 4 can be a straight strip or a curved shape. Its advantages are high precision, smooth edges, and minimal stray light.

[0025] For a 25µm slit, the processing error of stainless steel or molybdenum sheets is generally around ±2 to ±5µm. Therefore, the spectral linewidth caused by the incident slit will have an error of ±5% to ±15%, resulting in poor consistency of the spectrometer's specifications. In contrast, this solution achieves an accuracy of ±0.1µm, with a spectral linewidth error of only 0.4%, and its spectral resolution consistency is far superior to that of traditional slits.

[0026] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A glass optical slit structure integrated with a filter function, comprising a substrate (1), characterized in that: The base (1) is provided with a plating layer (2) and an insulation layer (3) on both sides, the outer side of the insulation layer (3) is provided with a metal coating (5), the material of the base (1) is one of quartz, glass, zinc selenide and germanium, the insulation layer (3) is formed by plating silver on the surface of the base (1), the metal coating (5) is formed by black chromium on the surface of the insulation layer (3), the plating layer (2) is formed by vacuum evaporation or ion sputtering, and the slit (4) is formed by reserving a blank area when the base (1) is plated with the insulation layer (3) and the metal coating (5).

2. The glass optical slit structure integrated with a light filtering function according to claim 1, characterized in that: The thickness of the metal coating (5) is 300 nm.

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