Patent ID: 7800292

Claim:
A vacuum envelope, comprising: a first substrate; a second substrate facing the first substrate; a side member located between the first substrate and the second substrate at peripheries of the first substrate and the second substrate to seal the vacuum envelope and maintain a substantially uniform distance between the first substrate and the second substrate along the peripheries; a first spacer disposed between the first substrate and the second substrate at an active area of the vacuum envelope; and a second spacer disposed between the first substrate and the second substrate at a non-active area of the vacuum envelope, the non-active area surrounding the active area, wherein a height of the first spacer is greater than a height of the second spacer, and wherein a height of the side member is less than the height of the second spacer, wherein a difference between the height of the first spacer and the height of the second spacer is less than 50 μm.