Electron tube and a method for manufacturing same

An electron tube having one or more ring-less getters of a tablet shape formed by fabricating a getter material, wherein the one or more ring-less getters having opposite first and second surfaces are mounted in a vessel of the electron tube without using containers and a light is irradiated on a first surface of the one or more ring-less getters to thereby activate the one or more ring-less getters, wherein the one or more ring-less getters are volatile and getter films are formed in the vessel by irradiating the light onto the one or more ring-less getters in order to evaporate the one or more ring-less getters,

• wherein the vessel includes a front substrate and a back substrate facing the front substrate, the front substrate being assembled to face the back substrate with a side plate therebetween, and wherein each of the one or more ring-less getters is attached to the front substrate or the back substrate by an intermediate adhesive layer having a same shape as a respective one of said ring-less getters and extending between said second surface and the front or back substrate, said respective one of said ring-less getters thereby being attached to said front or back substrate without using a supporting member other than said intermediate adhesive layer.