English
Optical filter
2025.03.04
The filter is an optical filter or optical element that is mainly used to select a specific band of light.
No.1 Working principle
The working principle of the filter is mainly based on the phenomena of light interference, diffraction, absorption and reflection. It can selectively transmit or reflect light of different wavelengths, so as to achieve the purpose of screening light.
No.2 Type and structure
01 Type
According to the different working principles and production materials, filters can be divided into many types, such as absorption filters and interference filters. Among them, interference filters include thin film filters, interference filters and Fabry-Perot filters.
02structure
The structure of the filter may be relatively simple, such as a single-layer film absorption filter, or it may be more complex, such as a color filter, which is usually composed of a glass substrate, a black matrix, a color layer, a protective layer, etc.
No.3 Performance parameter
01Transmittance
Indicates the degree of transmission of the filter to a specific wavelength of light, usually expressed as a percentage. High transmittance filters are often used for shooting scenes that require high resolution, while low transmittance filters can be used in situations such as laser protection.
02Reflectance
High reflectance filters can be used to reflect specific wavelengths of light, while low reflectance helps reduce light loss and improve imaging quality
03Absorptivity
Although not directly measured, understanding the absorption characteristics of the filter is crucial to evaluating its overall performance. High absorption filters can effectively absorb unwanted light and reduce stray light interference.
04Cut-off wavelength
Determining the specific wavelength point at which the filter begins to significantly block light is crucial for situations where the light band is precisely controlled.
05Band width
Measure the width of the wavelength range through which the filter allows light to pass. The smaller the bandwidth, the higher the accuracy, and is suitable for applications where a specific wavelength range of light needs to be selected.
No.4 Application field
01 photography
It is used to eliminate or weaken the reflection in the light, improve the shutter speed, and enhance the picture contrast.
02 Optical communication
It is used to select a specific wavelength optical signal to achieve signal separation and transmission.
03 Medical diagnosis
It is used to selectively shield or pass through laser light of different wavelengths in eye surgery, and laser protection.
04 Optical measurement
Used for spectral analysis, color measurement, light intensity measurement, etc.
05 Industrial application
Such as machine vision, semiconductor packaging, lithography machines, laser cutting and so on.
No.5 Production process and material
The production process and material of the filter have an important influence on its performance. High-quality materials (such as high transmittance glass, plastic, etc.) and advanced processes (such as coating technology, lithography technology, etc.) can ensure that the filter has higher performance and longer service life.
No.6 Sum up
As an important optical component, filter plays a key role in many fields. By understanding its working principle, type and structure, performance parameters and application fields and other aspects of knowledge, you can better understand the role and value of the filter.
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