Combined multi-channel optical filter

Abstract

The utility model discloses a combined multi-channel optical filter, which comprises a substrate, a main peak film system and a secondary peak cutting film layer, the main peak film system is arranged on the upper surface of the substrate, the secondary peak cutting film layer is arranged on the lower surface of the substrate, the main peak film system comprises at least nine independent main peaks, each main peak has different spectral bandwidths, and the main peak film system is arranged on the lower surface of the substrate. According to the optical filter provided by the invention, the main peaks are arranged in the optical filter, the spectral bandwidth difference between the adjacent main peaks is less than 100nm, the arrangement of the antireflection film and the black film effectively reduces reflection and crosstalk, the spectral selectivity and transmittance of the optical filter are improved, and the optical filter has the characteristics of high transmittance, low cost, simple structure and stable performance, can meet the filtering requirements of multiple wavebands such as ultraviolet light, visible light and near-infrared light, and has wide application prospects. The method is widely applicable to high-precision optical systems such as spectral analysis, laser detection and remote sensing equipment.

Description

TECHNICAL FIELD

[0001] The utility model relates to a combined multi-channel filter. BACKGROUND

[0002] With the continuous development of optical technology, especially in the fields of spectral analysis, optical communication, laser technology and remote sensing, the demand for filters in optical systems is becoming higher and higher. Traditional filters can usually only realize single-channel filtering function and cannot meet the demand of modern optical systems for multi-channel filtering. Especially in some high-precision, multi-wavelength application scenarios, the traditional filters have problems such as complex structure, high cost and unstable performance when processing multiple wavelength channels, which makes them unable to effectively meet the needs of refinement and customization.

[0003] In many modern optical systems, especially in multi-spectral imaging, astronomical observation, laser spectroscopy and multi-channel spectral analysis applications, it is necessary to filter out multiple specific wavelength ranges of light signals in one system. In order to achieve this goal, multiple filtering channels must be accurately matched and be able to provide stable transmittance in a wide wavelength range. However, the existing multi-channel filter design often has great challenges in performance, manufacturing complexity and cost. For example, when designing a multi-channel filter, how to ensure the transmittance stability between each wavelength channel, how to avoid crosstalk between different channels, and how to reduce the overlapping area of spectral bandwidth while ensuring high transmittance, are important technical problems that affect the design and application.

[0004] Therefore, there is an urgent need for a new type of combined multi-channel filter design scheme for technicians in the field, which ensures that each wavelength channel has high transmittance and the overlapping area between channels has low transmittance, avoiding crosstalk between different wavelengths. UTILITY MODEL CONTENT

[0005] The utility model aims at solving the above technical problems of the prior art, and provides a combined multi-channel filter, which solves the technical problems of unstable multi-channel filtering performance, large spectral bandwidth overlap and crosstalk between channels in the prior art by reasonably designing the structure of the substrate, main peak film system, secondary peak film layer and antireflection film and black film. The specific technical solutions are as follows:

[0006] The application discloses a combined multi-channel filter, which comprises a substrate, a main peak film system and a sub-peak film layer, the main peak film system is arranged on the upper surface of the substrate, the sub-peak film layer is arranged on the lower surface of the substrate, an antireflection film is arranged on the upper surface of the main peak film system, a black film is arranged outside the upper surface area of the antireflection film, a black film is arranged outside the upper surface area of the sub-peak film layer, the main peak film system comprises at least nine main peaks, the spectral bandwidths between the main peaks are all different, and the difference between the spectral bandwidths of adjacent main peaks is less than 100 nm.

[0007] Further, the substrate is optical glass, sapphire or other transparent materials, the thickness of the substrate is not more than 2 mm, the optical glass and sapphire have high transmittance and excellent high-temperature resistance, which can ensure the stability of the filter in a wide wave band and the filter is not easily affected by external environmental changes, the thickness of the substrate is limited within 2 mm, which not only ensures the thinness of the filter, but also ensures the sufficient structural strength, and meets the use requirements in different applications.

[0008] Further, the sub-peak film layer adopts high-low refractive index dielectric film layers.

[0009] Further, the antireflection film adopts fluoride or oxide materials, and the thickness of the antireflection film is 200-500 nm, these materials have good refractive index control performance, can accurately transmit light rays of different wavelengths by accurately adjusting the thickness and refractive index of the film layer, meanwhile, the sub-peak film layer adopts high-low refractive index dielectric film layers, which can effectively cut off unnecessary wavelength light rays and avoid unnecessary spectral leakage, and improve the selectivity and resolution of the filter.

[0010] Further, the spectral bandwidth range of the main peak film system includes ultraviolet light, visible light and near-infrared light regions, and the transmittance of each main peak is greater than 80%, which ensures that the filter can cover a wider wavelength range and meet the requirements of various optical systems, and at the same time, the spectral bandwidth difference between different main peaks is small, which avoids the wavelength overlapping problem between adjacent channels and reduces the crosstalk between different channels.

[0011] Further, the thickness of the black film is 100-200 nm, which is used for effectively absorbing excess light rays and preventing the mutual interference or crosstalk of light signals between different wavelength channels.

[0012] Further, the transmittance of the spectral overlap area between the main peak film system and the sub-peak film layer of the filter is less than 1%.

[0013] Beneficial effects: By precisely designing the film layer and spectral bandwidth of each main peak, high-efficiency filtering of nine or more independent wavelength channels can be realized, which meets the needs of multiple wavebands such as ultraviolet, visible light and near-infrared, and effectively separates light of different wavelengths; the antireflection film and black film design effectively reduces reflection and crosstalk, ensuring stable optical performance of the filter; in addition, the filter still maintains excellent performance in an extreme temperature range; by combining multiple independent filtering units, the design and manufacturing process of the filter is simplified, and the cost is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0014] Fig. 1 is a schematic diagram of a hierarchical structure of a combined multi-channel filter;

[0015] Fig. 2 is a schematic diagram of a front structure of a combined multi-channel filter;

[0016] In the figure: 1, black film, 2, sub-peak film layer, 3, substrate, 4, main peak film system, 5, antireflection film. DETAILED DESCRIPTION

[0017] In order to deepen the understanding of the present application, the present application will be further described in conjunction with the embodiments and drawings, which are only used to explain the present application and do not constitute a limitation on the protection scope of the present application.

[0018] Please refer to Figs. 1-2 A combined multi-channel filter, comprising a substrate 3, a main peak film system 4 and a sub-peak film layer 2, the main peak film system 4 is arranged on the upper surface of the substrate 3, the sub-peak film layer 2 is arranged on the lower surface of the substrate 3, an antireflection film 5 is arranged on the upper surface of the main peak film system 4, a black film 1 is arranged outside the upper surface area of the antireflection film 5, a black film 1 is arranged outside the upper surface area of the sub-peak film layer 2, the main peak film system 4 comprises at least nine main peaks, the spectral bandwidth between the main peaks is different, and the difference in spectral bandwidth between adjacent main peaks is less than 100 nm.

[0019] The substrate 3 is made of optical glass, sapphire or other transparent materials, and the thickness of the substrate 3 is not more than 2 mm; the sub-peak film layer 2 is made of high and low refractive index dielectric film layer; the antireflection film 5 is made of fluoride or oxide material, and the thickness of the antireflection film 5 is 200-500 nm; the spectral bandwidth range of the main peak film system 4 includes ultraviolet, visible and near-infrared regions, and the transmittance of each main peak is greater than 80%; the thickness of the black film 1 is 100-200 nm; the transmittance of the spectral overlap region between the main peak film system 4 and the sub-peak film layer 2 of the filter is less than 1%.

[0020] For a clearer understanding, the following examples are described in detail.

[0021] In a specific embodiment, the substrate 3 is made of BK7 optical glass with a thickness of 1.5 mm; the main peak film system 4 is a multi-layer dielectric film made of magnesium fluoride MgF2 and SiO2, the thickness of the film layer ranges from 50 nm to 200 nm, and the specific thickness is accurately adjusted according to the transmission wavelength range of each main peak; the material of the secondary peak film layer 2 is aluminum fluoride AlF3, and the thickness is 30 nm to 100 nm; the material of the anti-reflection film 5 is magnesium fluoride MgF2 or calcium fluoride CaF2, and the thickness is 10 nm; the material of the black film 1 is aluminum film, and the thickness is 5 nm, which is used on the surface of the main peak film system 4, the anti-reflection film 5 and the secondary peak film layer 2 to prevent crosstalk between different channels.

[0022] The following are specific manufacturing steps:

[0023] An optical glass substrate 3 is selected, and a mechanical polishing technique is used to ensure that the surface of the substrate 3 is smooth and flat, with an optical surface roughness of no more than 1 nm. The surface of the substrate 3 is cleaned to remove all oil and small particles, ensuring the adhesion of subsequent film layers. A physical vapor deposition technique is used to deposit a multi-layer dielectric film on the upper surface of the substrate 3. The thickness and refractive index of the film layer are accurately controlled according to the requirements of each wavelength channel to ensure the spectral bandwidth range and transmittance of each main peak. A metal film or high refractive index dielectric film is deposited on the lower surface of the substrate 3 to control the thickness and refractive index of the film layer, ensuring high cutoff rate for unwanted wavelength light. An anti-reflection film 5 with a thickness of 10 nm is deposited on the surface of the main peak film system 4. Black films 1 are deposited on the surface area outside the main peak film system 4, the anti-reflection film 5 and the secondary peak film layer 2, respectively, to eliminate crosstalk between channels. Multiple filter units are combined together, and each filter unit is bonded to a transition sheet with epoxy glue, and then the transition sheet is bonded to a support. After gluing, it is left to stand for 12 hours to ensure that the glue is completely cured, and the bubbles in the epoxy glue are gently chased out to avoid affecting the optical performance.

[0024] After the assembly of the filter is completed, the spectral transmittance test is carried out, and the spectral transmittance of each wavelength channel is measured using a spectrometer to ensure that the transmittance of each channel is greater than 80%, and the transmittance difference between adjacent wavelength channels meets the design requirements. The stability of the filter under different temperature and humidity conditions is tested to ensure that it can still maintain excellent performance in an environment of -40℃ to +75℃.

[0025] Finally, it should be pointed out that the above embodiments are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced equivalently without departing from the spirit and scope of the present application, and all should be covered in the scope of the claims of the present application.

Claims

1. A combined multi-channel filter, characterized in that, The filter comprises a substrate, a main peak film system and a sub-peak film layer, the main peak film system is arranged on the upper surface of the substrate, the sub-peak film layer is arranged on the lower surface of the substrate, an anti-reflection film is arranged on the upper surface of the main peak film system, a black film is arranged on the outer surface of the upper surface area of the anti-reflection film, a black film is arranged on the outer surface of the upper surface area of the sub-peak film layer, the main peak film system comprises at least nine main peaks, the spectral bandwidths of the main peaks are different, and the difference between the spectral bandwidths of adjacent main peaks is less than 100 nm.

2. The combination multi-channel filter according to claim 1, wherein, The substrate is optical glass, sapphire or other transparent material, and the thickness of the substrate is not more than 2 mm.

3. The combination multi-channel filter of claim 1, wherein, The sub-peak film layer adopts a high-low refractive index dielectric film layer.

4. The combination multi-channel filter of claim 1, wherein, The anti-reflection film adopts fluoride or oxide material, and the thickness of the anti-reflection film is 200-500 nm.

5. The combination multi-channel filter of claim 1, wherein, The spectral bandwidth range of the main peak film system includes ultraviolet light, visible light and near-infrared light regions, and the transmittance of each main peak is greater than 80%.

6. The combination multi-channel filter of claim 1, wherein, The thickness of the black film is 100-200 nm.

7. The combination multi-channel filter of claim 1, wherein, The transmittance of the spectral overlap area between the main peak film system and the sub-peak film layer of the filter is less than 1%.

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