Products & Solutions

ND filter

An ND filter is a filter that controls the transmittance (density) to a specific value within any wavelength band. It can be manufactured using either a metal film or a dielectric multilayer film. Furthermore, it can be produced for each wavelength band from ultraviolet to infrared.

Usage

Industrial equipment

Sensor sensitivity calibration
Light source dimming

Function

Intensity

Inquiry

Features

An ND (neutral density) filter attenuates the amount of incident light by a certain amount and is used to compensate for camera and sensor sensitivity. It can obtain a flat transmittance spectrum in the desired wavelength band. We can manufacture this filter for each wavelength band from ultraviolet to infrared.

ND filters come in two types, reflective and absorbent. The reflective-type has a multilayer dielectric film coated on a glass substrate. The absorbent-type has a metal film with light absorbing characteristics coated on a glass substrate.
We can also make a non-reflective ND filter that suppresses the reflection of incident light on the substrate surface.

ND filter characteristics are indicated by transmittance or optical density (OD).
The relationship between transmittance (T%) and OD is as follows.