Manufacturing method of vacuum airtight container

A method of manufacturing a vacuum airtight container, comprising:

• a sealant applying step of applying a sealing material to a container;
• a baking step of baking, in a vacuum atmosphere, the container having a first non-evaporable getter and a second non-evaporable getter with an activation temperature higher than that of the first non-evaporable getter;
• and
• a sealing step of, after the baking step, sealing the container with the sealing material to provide an airtight container, wherein
• the baking step comprises steps of:
• baking the entire container by increasing the temperature of the container to a temperature T1, which is equal to or higher than the activation temperature of the first non-evaporable getter and lower than the activation temperature of the second non-evaporable getter;
• maintaining the container at the temperature T1 for a period of time to sufficiently activate the first non-evaporable getter;
• increasing the temperature of the container from a temperature T1 to a temperature T2, which is higher than the activation temperature of the second non-evaporable getter and a melting point of the sealing material;
• maintaining the container at the temperature T2 for a period of time to sufficiently activate the second non-evaporable getter;
• and
• decreasing the temperature of the container from the temperature T2 to a temperature which is lower than the melting point of a sealing material, wherein
• activation of the second non-evaporable getter is completed before completing sealing of the container.