| 摘要 |
PURPOSE:To facilitate mass production of subminiature chip type ceramic filters which are packaged in a plane, by connecting protection plates on both sides of a piezoelectric plate in one body with layers of ultrasonic-wave absorbers interposed, and by separating the body into individual filters. CONSTITUTION:On both the top and reverse sides of a piezoelectric plate 11 made of a PZT, etc., conductive patterns for filters are provided. Respective filter units of this pattern have vibration parts 14, coupling capacitor parts, and lead-out electrode parts to the flanks. To surfaces, which are not near the vibration parts 14, on both the sides of the piezoelectric plate 11, protection plates 16a and 16b, such as ceramic plates and resin plates, are bonded in one body. Then, the plate is cut into respective filter units, and each lead-out electrode part is connected to an external electrode 17 provided to the protection plate 16 previously. |
