Patent ID: 6929524

Claim:
A method of producing a vacuum envelope comprising the steps of: preparing a first substrate having a thickness T 1 ; bonding a plurality of spacers to the first substrate; arranging a second substrate, having a thickness T 2 , to be disposed in opposition to the first substrate and sandwiching therebetween the spacers; and forming the vacuum envelope between the first and second substrates under a load, wherein a ratio η defined by S/A, in which A is an internal cross-sectional area of the vacuum envelope in a cross-section parallel to a plane of the first substrate opposed to the second substrate, or a plane of the second substrate opposed to the first substrate, and S is the total cross-sectional area of the plurality of spacers on such cross-section, satisfies a relation 0.78%≦η≦7.8%, with T 1 and T 2 in a range 0.5-5 mm, and said step of forming the vacuum envelope is conducted with exerting a load to hold the first and second substrates together.