US 12,122,713 B2
Glass
Hirofumi Tokunaga, Tokyo (JP); and Kazutaka Ono, Tokyo (JP)
Assigned to AGC INC., Tokyo (JP)
Filed by AGC INC., Tokyo (JP)
Filed on Sep. 10, 2020, as Appl. No. 17/016,646.
Application 17/016,646 is a continuation of application No. PCT/JP2019/010426, filed on Mar. 13, 2019.
Claims priority of application No. 2018-046854 (JP), filed on Mar. 14, 2018.
Prior Publication US 2020/0407264 A1, Dec. 31, 2020
Int. Cl. C03C 3/087 (2006.01); C03C 3/091 (2006.01); G11B 5/73 (2006.01); G11B 7/2531 (2013.01)
CPC C03C 3/087 (2013.01) [C03C 3/091 (2013.01); G11B 5/73921 (2019.05); G11B 7/2531 (2013.01); C03C 2201/12 (2013.01); C03C 2203/20 (2013.01)] 21 Claims
 
1. A planar antenna comprising a glass having a density of 2.60 g/cm3 or lower, a Young's modulus of 88 GPa or more, a strain point of 650 to 720° ° C., a temperature T4 at which a glass viscosity reaches 104 dPa·s of 1,320° C. or lower, a glass surface devitrification temperature (Tc) of T4+20ºC or lower, and an average coefficient of thermal expansion of 30×10−7 to 43×10−7/° C. at 50 to 350° C., and
comprising, as represented by mol % based on oxides,
50 to 80% of SiO2,
8 to 20% of Al2O3,
0 to 5% of B2O3,
0 to 15% of MgO,
0 to 12% of CaO,
0 to 10% of SrO,
0 to 10% of BaO,
0.005 to 0.2% of Na2O,
0.001 to 0.5% of F,
0.005 to 0.5% total of alkali metal oxides selected from the group consisting of Li2O, Na2O and K2O, and
0 to 1% of P2O5,
wherein MgO+CaO+SrO+BaO is 18 to 22%.