Surface acoustic wave element, method of producing the same, and method of changing resonation frequency of the same

A surface acoustic wave element comprising:

• a piezoelectric member;
• a comb-teeth electrode arranged on the piezoelectric member;
• and
• a reflector arranged on the piezoelectric member so as to reflect a surface acoustic wave transmitted from the comb-teeth electrode, wherein
• the reflector has a plurality of areas, each of the areas having a frequency to have a largest reflection efficiency, and the frequencies are different from each other,
• the plurality of areas are arranged in a direction perpendicular to a wave transmitting direction of the surface acoustic wave in a section where the surface acoustic wave transmitted from the comb-teeth electrode is reflected,
• the reflector has a plurality of electrodes arranged in the wave transmitting direction,
• the plurality of areas of the reflector has:
• an open area in which the electrodes are not shorted with each other and
• a short area in which the electrodes are shorted with each other,
• the reflector is arranged on both sides of the comb-teeth electrode in the wave transmitting direction,
• the reflector has an electrode pattern symmetric with respect to an axis, and
• the axis is defined to extend approximately perpendicular to the wave transmitting direction, and to pass through an approximately center position of the comb-teeth electrode.

A method of producing a surface acoustic wave element, the surface acoustic wave element comprising:

• a piezoelectric member;
• a comb-teeth electrode arranged on the piezoelectric member;
• and
• a reflector arranged on the piezoelectric member so as to reflect a surface acoustic wave transmitted from the comb-teeth electrode, wherein
• the reflector has a plurality of areas, each of the areas having a frequency to have a largest reflection efficiency, and the frequencies are different from each other,
• the plurality of areas are arranged in a direction perpendicular to a wave transmitting direction of the surface acoustic wave in a section where the surface acoustic wave transmitted from the comb-teeth electrode is reflected,
• the reflector has a plurality of electrodes arranged in the wave transmitting direction,
• the plurality of areas of the reflector has:
• an open area in which the electrodes are not shorted with each other and
• a short area in which the electrodes are shorted with each other,
• the reflector is arranged on both sides of the comb-teeth electrode in the wave transmitting direction,
• the reflector has an electrode pattern symmetric with respect to an axis, and
• the axis is defined to extend approximately perpendicular to the wave transmitting direction, and to pass through an approximately center position of the comb-teeth electrode,
• the producing method comprising:
• forming the comb-teeth electrode on the piezoelectric member;
• forming the reflector on the piezoelectric member, such that all of the electrodes of the reflector are connected with each other by a connector;
• and
• cutting the electrodes of the reflector so as to separate the reflector into the open area and the short area.