Narrowband optical filter and film plating method thereof

A narrow-band filter and film stack technology, which is applied in optics, optical components, instruments, etc., can solve problems such as low image distortion, poor filter surface deformation, and large stress difference, so as to avoid deformation and reduce base Sheet deformation, coating cost reduction effect

Inactive Publication Date: 2017-09-22
上海兆九光电技术有限公司
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  • Abstract
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  • Application Information

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Problems solved by technology

In addition, when the film thickness of the secondary film is far greater than the film thickness of the main film, the stress produced by the main film and the secondary film on the substrate is very different, causing the substrate to deform, resulting in the deterioration of the surface shape of the filter and resulting in poor imaging quality. Correspondingly worse
Make it difficult for the projection surface of the filter to meet the requirements for low image distortion

Method used

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  • Narrowband optical filter and film plating method thereof
  • Narrowband optical filter and film plating method thereof
  • Narrowband optical filter and film plating method thereof

Examples

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Embodiment 1

[0022] Taking the BP850 / 30 product as an example, the design center wavelength is 850nm, the bandwidth is 30nm, the cut-off depth is OD4, and the cut-off range is 200-1200nm.

[0023] Its preparation process is as follows:

[0024] The first step is to design the main membrane stack 2 of the light control method, so that the refractive index of the equivalent substrate formed by the combination of the main membrane stack 2 and the glass substrate 1 is equivalent to that of the glass substrate 1 at 850 nm.

[0025] According to the optical thin film theory, the characteristic matrix for the calculation of optical multilayer film properties is:

[0026]

[0027]

[0028] no j is the refractive index of the jth film, d j is the physical thickness of the jth film, θ j is the incident angle of light in the jth film, λ is the reference wavelength, η j is the admittance of the thin film of the jth layer, η j =n j -ik j , when the film layer is a non-absorbing film, k j ...

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Abstract

The invention discloses a coating process for a narrow-band filter, which comprises the following steps: coating a main membrane stack on one side of a blank glass substrate, so that the main membrane stack and the blank glass substrate form an equivalent base. The equivalent refractive index of the equivalent substrate at the center wavelength is equal to the refractive index of the blank glass substrate; the first sub-film stack is coated on one side of the equivalent substrate, and the second sub-film stack is coated on the other side of the equivalent substrate. Two membrane stacks. The invention can prevent the thickness of the secondary film layer from being too thick compared with that of the main film layer, so that the stress on both sides of the substrate is basically balanced, the deformation of the substrate is reduced, and the imaging quality is guaranteed.

Description

technical field [0001] The invention belongs to the technical field of vacuum coating, and in particular relates to a coating method for a narrow-band filter. And narrowband filters produced by this method. Background technique [0002] Optical filter is an optical device that can separate a certain band of monochromatic light from composite light, and it is widely used in various fields of optoelectronic industry. The coating of the optical filter is realized by using the principle of F-P interference to precisely control the optical thickness or physical thickness of each film layer. In practice, the requirements for the central wavelength position of the narrowband filter are very strict, and its tolerance is generally within 20% of the bandwidth. In the conventional process, the processing step is to plate a film stack combination with a regular λ / 4 optical thickness on one side of the glass substrate by the optical extremum method. At the same time, a sub-film stack ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G02B5/28
CPCG02B5/285
Inventor 罗新华
Owner 上海兆九光电技术有限公司
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