Optical Window Lids

Kyocera offers optical window lids in a wide range of materials and can customize designs to meet challenging specifications.

Material Characteristics

Each material's primary characteristics, coefficient of thermal expansion (CTE), and optical transmission properties are summarized below.

Material		Features	CTE (ppm/K) *Reference Value	Transmission Property
Borosilicate Glass	No.1	Low cost Many use cases Feasible for alumina package	7.2	Visible / NIR
	No.2	Low level α-ray glass Available for alumina packages	6.7
	No.3	Abundant experience in glass industry	8.6 / 8.3
	No.4	Available for AlN packages	3.2
	No.5	Radiation-hardened	8.2
Non-Alkaline Glass		Available for AlN packages	3.17
Quartz Glass		High transmittance in UV-A/B/C range	0.5	UV / Visible / NIR
Sapphire		High rigidity High transmittance in the UV-A/B ranges	6.7 (parallel to C-axis) / 5.0 (perpendicular to C-axis) *Depending on manufacturer
Artificial quartz		Optical low-pass filter (Moiré Prevention) Available for organic packages	*Depending on crystal orientation
Silicon		High transmittance in infrared range Can provide hermetic sealing with metal bonding	4.2	IR
Germanium		High transmittance in infrared range Can provide hermetic sealing with metal bonding	5.5

*CTE varies by manufacturer and is provided as a reference value as materials and temperature conditions may vary.

Transmittance data for typical materials (reference values)

Below transmittance data reflect manufacturer's specifications.

Optical properties can be customized by depositing coating materials.
Please contact us for details.