Glossary - alphabet order - "I"

I²C-BUS interface

This is a type of serial interface, originally proposed by Royal NXP semiconductors.

IR-cut filter coating

An spectral property of IR cut coating or IR absorption glass, expressed by a wavelength that has transmissivity of 50 %. (See IR glass.)

Incident angle

It is an angle between the direction of incident light and the line at the incident point that is normal to a sample surface.

Infrared absorption glass

It is a glass that absorbs infra-red light (same as IR cut coating). IR cut coatings are a reflective type of filter with almost non thickness, while a IR absorption glass is an absorption type filter with thickness for controlling transmissivity. If IR cut coating is used in a CCD or CMOS device of a camera, problematic ghost images are generated by reflections. The infrared absorption glass avoids it.

Initial tolerance

This refers to initial deviation (Δf) between the actual frequency (measured value) and the rated value (f) at an ambient temperature of +25 ℃. This differential is expressed as a ratio (Δf/f).

Reference: Frequency tolerance

Insulation resistance

This is the resistance value between the leads and between the leads and the case.


It is a multi-layer coating with a spectral characteristic that filters out infra-red light (light with wavelength of 650 nm or above). A CCD or CMOS device is sensitive not only to wavelengths (400 to 650 nm) corresponding to certain colors, but wavelengths outside this region when images are picked up by the device. In particular, light in the infra-red region called heat rays blurs outlines of an image and casts a reddish tinge on an entire image. This coating shields such infra-red light for preventing these troubles.


An inverter is a circuit element that outputs a signal whose high/low status is the reverse of the corresponding input signal. Inverters are used in crystal oscillation circuit to help generate crystal oscillation.

Reference: Crystal oscillation circuit

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