Patent ID: 7741759

Claim:
An electron tube comprising: an envelope including a tube having a side portion comprising silicon and having at least one end pan formed with an opening, and a joining member airtightly joined to the opening, the joining member comprising a joining part; a photocathode positioned within the envelope, the photocathode emitting a photoelectron into the envelope in response to light incident onto the photocathode from outside the envelope; and a multiplier part positioned within the envelope and multiplying the photoelectron; wherein the tube side portion includes a first multilayer metal film formed at the opening which comprises a first metal film made of titanium, a first metal film made of platinum, and a first metal film made of gold, and wherein the films of the first multilayer film are successively laminated such that the first metal film made of platinum is positioned closer to the opening than is the first metal film made of titanium, and the first metal film made of gold is positioned closer to the opening than is the first metal film made of platinum; wherein the joining member includes a second multilayer metal film formed at the joining part which comprises a second metal film made of titanium, a second metal film made of platinum, and a second metal film made of gold, and wherein the films of the second multilayer film are successively laminated such that the second metal film made of platinum is positioned closer to the joining part than is the second metal film made of titanium, and the second metal film made of gold is positioned closer to the joining part than is the second metal film made of platinum; wherein a joint material joins together the tube side portion and the joining member, the joint material comprising indium and being located between the first and second multilayer metal films; wherein the multiplier part is separated from the tube side portion; and wherein a first intermediate layer comprising aluminum or silicon oxide is formed beneath the first multilayer metal film at the opening and a second intermediate layer comprising aluminum or silicon oxide is formed beneath the second multilayer metal film at the joining part.