Push-button switch with part to a wire rod exposed to an inside bottom of housing to form a contact portion

A push-button switch comprising:

• a housing enclosing a receptacle portion;
• a fixed terminal formed by a wire rod embedded in the housing and partially projecting to an exterior of the housing;
• a fixed contact arranged within the receptacle portion and having a raised contact portion electrically connected to the fixed terminal, said raised contact portion protruding from an inner bottom surface of the housing toward an interior area of the receptacle portion, said raised contact portion having a rounded upper surface comprising an electrical contact point;
• and
• a dome-like movable contact disposed within the receptacle portion and capable of moving into surface-contact with the electrical contact point of the fixed contact, wherein a groove is formed in the upper surface of the raised contact portion of the fixed contact, said groove being formed adjacent to the electrical contact point so as to provide an area for the accumulation of dust away from the electrical contact point, thereby preventing the dust from interfering with the surface-contact of the movable contact with the electrical contact point of the fixed contact.