D28x4 Fused Silica Laser Protective Window 27.9*4.1 Quartz Optical Lens Protection Window Fiber Laser Engraving Machines
D28*4mm Laser Protective Windows
Material: Quartz Fused Silica
Wavelength: 1064nm
Transmittance: 99.5%
Application: Fiber YAG Laser Cutting Welding Machine
What we need to understand is that the light that the human eye can see is limited, and not all light can be seen by us. Then the light that the human eye can see is called visible light. Visible light is the human eye in the electromagnetic spectrum. The perceptible part, the visible spectrum does not have a precise range, the wavelength of electromagnetic waves that the average human eye can perceive is between 400nm-700nm, but some people can perceive electromagnetic waves with a wavelength of about 380-780nm, and the wavelengths are different. Electromagnetic waves cause different color perceptions in the human eye. The colors corresponding to visible light from long to short are: red, orange, yellow, green, blue, indigo, and violet.
Ultraviolet light: 200-380nm
Violet: 400-435nm
Blu-ray: 450-480nm
Blue light: 480-490nm
Blue light green: 490-500nm
Green light: 500nm-560nm
Yellow light green: 560-580nm
Yellow light: 580nm-595nm
Orange light: 595-605nm
Red light: 610-730nm
Near infrared red light: 800-1300nm
Mid-infrared red light: 1600nm-4600nm
Finally, let's take a look at the color presented by the material, which is closely related to light. When the light hits the material, due to the different degrees of reflection, refraction, scattering, absorption, and transmission of the light of different wavelengths, the material will appear different. s color. A surface that diffusely reflects all wavelengths of light is white, while a surface that absorbs all wavelengths of light is black.
Definition of filter
First of all, we need to know that a filter is an optical device, that is, it transmits light waves of the required wavelengths, and optical devices that filter out unwanted wavelengths of light are called filters. From this definition, the commonality of all filters is that they cannot make the image brighter, because all filters absorb certain wavelengths of light more or less, resulting in darkening of the object.
The principle of the filter:
It is made by coating an optical film on the substrate or adding dyes in it, which can absorb or reflect a specific wavelength band in the light wave or precisely select a small range of light waves to pass through, so as to obtain various spectral characteristics.
Filter products on the market are mainly classified according to spectral characteristics, spectral bands, film materials, application fields, etc.:
According to the spectral band, it is divided into: UV filter, visible filter, near-infrared filter, mid-infrared filter, far-infrared filter;
According to spectral characteristics, it is divided into: interference filter, spectral filter, neutral density filter, reflection filter, negative band-stop filter, polarizing filter, etc.;
Common interference filters are divided into cut-off filters and band-pass filters. They use the principle of interference to only pass light in a specific spectral range, and are usually composed of multilayer films.
Cutoff filter:
The cut-off filter can divide the spectral range into two areas, one area is called the cut-off area, in which the light cannot pass through, and the other area is called the pass-band area, in which the light can fully pass through or be highly transparent. The cut-off filter has a short-wave pass filter (allowing only light in the short-wave direction to pass, also called a low-pass filter) and a long-pass filter (only allowing light in the long-wave direction to pass, also called a high-pass filter).
Bandpass filter:
The bandpass filter only allows the light of a specific band to pass, and the light outside the passband is cut off. The optical indicators of the bandpass filter are mainly the central wavelength (CWL), the half bandwidth (FWHM), according to the needs, the bandpass filter The passband can be from infrared to ultraviolet. We often refer to narrow-band filters (bandwidths less than 30nm) as narrow-band filters, while those with bandwidths greater than 60nm are called broadband filters.
According to the film material, it is divided into: soft film filter, hard film filter;
The hard-coated filter not only refers to the hardness of the film, but also its laser damage threshold, which is widely used in laser systems.
According to the scope of application, it is divided into: filters for medical biochemical instruments, filters for fluorescence microscopes, multi-band hard-coat filters, filters for beauty instruments, laser ranging filters, security monitoring filters, etc.
Finally, let's talk about the color filter that many people in the industry say. Color filter is also called color filter and color filter. It is not a filter. It is divided into many types such as red filter, green filter. filter, purple filter, blue filter, yellow filter, etc., each filter can utilize its own color. They can be long-pass type or band-pass type, and they can be both coated color filters and colored glass.
