Claims
- 1. A package for hermetically containing an electronic device therein, said package comprising:
- an alumina base plate on which said electronic device can be mounted; and
- a glass plate window mounted to said alumina base plate so as to hermetically contain said electronic device, said glass plate window having a thickness of 0.7 mm or less, a thermal expansion coefficient in the range of about 50.times.10.sup.-7 /.degree. C. to about 75.times.10.sup.-7 /.degree. C. over a temperature range from about 30.degree. C. to about 380.degree. C., and a transmission of 40% or more through 1 mm thickness of said glass plate window for ultraviolet radiation having a wavelength of 253.7 nanometers, said glass plate window being free from ZnO and consisting essentially of SiO.sub.2 55-64%, Al.sub.2 O.sub.3 7-20%, B.sub.2 O.sub.3 11.5-14%, Li.sub.2 O 0-8%, Na.sub.2 O 7-20%, K.sub.2 O 0-4% and RO 0.5-7% on the basis of weight percent, R being at least one of Mg, Ca, Sr, and Ba, and said glass plate window having a surface layer in which alkaline metal ions are partially ion-exchanged with another alkaline metal ion having an ion radius larger than that or said first mentioned alkaline metal ions, so as to provide said surface layer with a compressive stress of at least 200 Kg.f/cm.sup.2.
- 2. The package of claim 1, wherein the ratio (Li.sub.2 O+Na.sub.2 O))/(Li.sub.2 O+Na.sub.2 O+K.sub.2 O) is 0.7 or more.
Related Cases
This is a continuation of U.S. application Ser. No. 07/573,378 filed Aug. 24, 1990 now abandoned.
US Referenced Citations (6)
Foreign Referenced Citations (2)
Number |
Date |
Country |
62-065954 |
Mar 1987 |
JPX |
1-014185 |
Mar 1989 |
JPX |
Continuations (1)
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Number |
Date |
Country |
Parent |
573378 |
Aug 1990 |
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