Optical glass and precision polished glass

Properties of Optical Glasses

A variety of glasses are available from Valley Design. This is an outline of optical, mechanical, thermal and electric properties of the most commonly requested glass types: Soda Lime, Pyrex, Borosilicate and Borofloat glasses.

Various windows, plates and disks that can be optically polished to better than 0.5 microinches (20/10), are excellent as substrates and also in semiconductor form for applications such as: resistor networks, thin and thick film microelectronics, vacuum vapor and sputtering depositions, photomasks, electro optics, semiconductor monitor wafers and other precision optical components.

Soda Lime Glass

7740-Pyrex, Borofloat Glass, Borosilicate Glass

  • Low coefficient of thermal expansion
  • High operating temperature
  • Chemical durability
  • Anodically bondable to Silicon
  • Properties of 7740-Pyrex

1737F-Alkaline Earth Aluminosilicate Glass (replaces 7509 glass)

  • High operating temperature (strain point 666°C)
  • Low coefficient of thermal expansion
  • Low thermal shrinkage
  • Properties of 1737F

0211-Alkali Zinc Borosilicate Glass

  • Transmittance in the visible and near infrared spectrums
  • Soda content is half that of Soda Lime glass
  • Maximum thickness is 0.3 mm
  • Properties of 0211

7070-Lithium Potash Borosilicate Glass

  • Relatively high operating temperature
  • Anodically bondable to Silicon
  • Microwave window applications
  • Low coefficient of thermal expansion
  • Excellent hermetic sealing characteristics
  • Properties of 7070

BK-7 Borosilicate Crown Glass

  • Most popular optical glass
  • Excellent transmission (350nm to 2000nm)
  • Low index of refraction
  • Properties of BK-7

AF-45 Modified Borosilicate Glass

  • Alkali-free in synthesis
  • Low coefficient of thermal expansion
  • Excellent thermal resistance
  • High luminous transmission
  • Properties of AF-45

D-263 Borosilicate Glass

All data is subject to normal manufacturing variations and is provided for reference purposes only. Customers are responsible for selecting the suitability of material for their intended application.

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Soda Lime Glass

Principal Uses

Mirrors, microslides, printed circuit substrates and electronic applications

Thermal/Mechanical Properties

Density (at 20°C/68°F): 2.44 g/cm³
Thermal Coefficient of Expansion (0/300°C): 8.36 x 10-5/°C
Strain Point: 490°C/ 914°F
Annealing Range:480°C-575°C/896°F-1067°F
Softening Point: 575°C/1067°F

Optical Properties

Refractive Index (λ=435): 1.523
(λ=645): 1.513
Optical transmission

Chemical Properties

Hydrolytic resistance: class 3

Electrical Properties

Dielectric Constant: E= 7.75

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7740 (Pyrex)

Principal Uses

Filter lens, sheet glass, tubing

Thermal/Mechanical Properties

Density (at 20°C/68°F): 2.23 g/cm³
Thermal Coefficient of Expansion (0/300°C): 32.5 x 10-7/°C
Strain Point: 510°C/950°F
Annealing Point: 560°C/1040°F
Softening Point: 821°C/1509.8°F

Optical Properties

Refractive Index(λ=589.3nm): 1.473
(λ=645): 1.513
Optical transmission

Chemical Properties

Hydrolytic resistance: class 1
Acid resistance: class 1
Alkali resistance: class 2

Electrical Properties

Dielectric Constant: E=4.6

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1737F Glass

Principal Use(s)

Substrates for flat panel displays

Thermal/Mechanical Properties

Density (at 25°C/77°F): 2.54 g/cm³
Thermal Coefficient of Expansion (0/300°C; 32/572°F): 37.6 x 10-7/°C; 21 x 10-7/°F
Strain Point: 666°C/1231°F
Annealing Point:721°C/1330°F
Softening Point:975°C/1787°F

Optical Properties

Refractive Index (λ=656.3nm): 1.5160
(λ=435.8nm): 1.5290
Optical transmission

Electrical Properties

Dielectric Constant: E=5.7

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7070

Principal Use(s)

Low loss electrical applications

Thermal/Mechanical Properties

Density (at 20°C/68°F): 2.13 g/cm³
Thermal Coefficient of Expansion (0/300°C; 32/572°F): 32 x 10-7/°C; 17.7 x 10-7/°F
Strain Point: 456°C/ 853°F
Annealing Point: 496°C/925°F
Softening Point: NOT MEASURABLE

Optical Properties

Refractive Index (λ=589,3nm): 1.469

Chemical Properties

Hydrolytic resistance: class 2
Acid resistance: class 2

Electrical Properties

Dielectric Constant: E= 4.0

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BK7

Thermal/Mechanical Properties

Density (at 20°C/68°F): 2.51 g/cm³
Thermal Coefficient of Expansion (20/300°C): 7.0 x 10-6/°C
Strain Point:°C/°F
Annealing Point:°C/°F
Softening Point:°C/°F

Optical Properties

Refractive Index(λ=582.1nm): 1.509
Optical transmission

Chemical Properties

Hydrolytic resistance: class 2
Acid resistance: class 1
Alkali resistance: class 2

Electrical Properties

Dielectric Constant: E=

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AF45

Principal Uses

LCD, solar cells, hybrid circuits, CCD covers, electroluminescent displays

Thermal/Mechanical Properties

Density (at 20°C/68°F): 2.72 g/cm³
Thermal Coefficient of Expansion (20/300°C): 4.5 x 10-6/°C
Strain Point: 627°C/1161°F
Annealing Point: 663°C/1225°F
Softening Point: 883°C/1621°F

Optical Properties

Refractive Index(λ=588nm): 1.5255
Optical transmission

Electrical Properties

Dielectric Constant: E= 6.2

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D263

Principal Use(s)

Touch control panels, LCD, solar cells, electroluminescent displays

Thermal/Mechanical Properties

Density (at 20º C/68 ºF): 2.51 g/cm³
Thermal Coefficient of Expansion (20/300°C; 68/572°F): 7.2 x 10-6/K
Strain Point: 529°C/984°F
Annealing Point: 557°C/1035°F
Softening Point: 736°C/1357°F

Optical Properties

Refractive Index (λ=546nm): 1.5255
(λ=588nm): 1.5230
Optical transmission

Chemical Properties

Hydrolytic resistance: class 1

Electrical Properties

Dielectric Constant: E= 6.7

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