Optical device and method for manufacturing optical device

A method of producing an optical device, comprising the steps of:

• preparing (i) a first housing having a window, (ii) a window glass plate, (iii) an optical element, and (iv) a second housing in which the optical element is to be fixed so that light enters the optical element via the window;
• connecting the window glass plate to the window of the first housing via a solder layer so as to (i) hermetically seal a space between the window glass plate and the first housing and (ii) form, in the solder layer, a void which is isolated from an external space and an internal space of the optical device, the solder layer completely surrounding the void;
• and
• connecting (i) the first housing to which the window glass plate is connected and (ii) the second housing in which the optical element is fixed so that an internal space of the first housing and the second housing is hermetically sealed.

An optical device, comprising:

• a housing that has a window;
• an optical element which is provided in the housing and which light enters via the window;
• a window glass plate with which the window is provided;
• and
• a connector that connects the window glass plate to the housing so that an internal space of the housing is hermetically sealed,
• the connector being formed of a solder layer,
• the solder layer having therein a void which is isolated from an external space and an internal space of the optical device,
• wherein a ratio of a first volume of the void to a second volume of the solder layer falls within the range of 1/4 to 1/2.