Surface acoustic wave resonator, surface acoustic wave oscillator, and electronic apparatus

A surface acoustic wave resonator comprising:

• an IDT that is disposed on a quartz crystal substrate of Euler angles (−1.5°≦φ≦1.5°, 117°≦θ≦142°, ψ) and excites a surface acoustic wave resonant in an upper part of a stop-band of the IDT;
• and
• inter-electrode finger grooves that are acquired by depressing the substrate located between electrode fingers configuring the IDT;
• and
• wherein, in a case where a wavelength of the surface acoustic wave is λ, and a depth of the inter-electrode finger grooves is G, 0.01λ≦G is satisfied,
• wherein, in a case where a line occupancy ratio of the IDT is η, the depth G of the inter-electrode finger grooves and the line occupancy ratio η satisfy one of the following relationships:
• −2.0000×G/λ+0.7200≦η≦−2.5000×G/λ+0.7775, wherein 0.0100λ≦G≦0.0500λ, and
• −3.5898×G/λ+0.7995≦η≦−2.5000×G/λ+0.7775, wherein 0.0500λ<G≦0.0695λ,
• wherein, in a case where a film thickness of the electrode fingers of the IDT is H and a relationship of 0<H≦0.005λ is satisfied, the following relationships are satisfied:
• ψ≦3.0°×G/λ+43.92°, wherein 0.0100λ≦G≦0.0695λ, and
• ψ≧−48.0°×G/λ+44.35°, wherein 0.0100λ≦G≦0.0695λ,
• wherein, in a case where a relationship of 0.005λ<H≦0.010λ is satisfied, the following relationships are satisfied:
• ψ≦8.0°×G/λ+43.60°, wherein 0.0100λ≦G≦0.0695λ, and
• ψ≧−48.0°×G/λ+44.00°, wherein 0.0100λ≦G≦0.0695λ,
• wherein, in a case where a relationship of 0.010λ<H≦0.015λ is satisfied, the following relationships are satisfied:
• ψ≦10.0°×G/λ+43.40°, wherein 0.0100λ≦G≦0.0695λ, and
• ψ≧−44.0°×G/λ+43.80°, wherein 0.0100λ≦G≦0.0695λ,
• wherein, in a case where a relationship of 0.015λ<H≦0.020λ is satisfied, the following relationships are satisfied:
• ψ≦12.0°×G/λ+43.31°, wherein 0.0100λ≦G≦0.0695λ, and
• ψ≧−30.0°×G/λ+44.40°, wherein 0.0100λ≦G≦0.0695λ,
• wherein, in a case where a relationship of 0.020λ<H≦0.025λ is satisfied, the following relationships are satisfied:
• ψ≦14.0°×G/λ+43.16°, wherein 0.0100λ≦G≦0.0695λ,
• ψ≧−45.0°×G/λ+43.35°, wherein 0.0100λ≦G≦0.0600λ, and
• ψ≧367.368°×G/λ+18.608°, wherein 0.0600λ≦G≦0.0695λ,
• wherein, in a case where a relationship of 0.025λ<H≦0.030λ is satisfied, the following relationships are satisfied:
• ψ≦12.0°×G/λ+43.25°, wherein 0.0100λ≦G≦0.0695λ,
• ψ≧−50.0°×G/λ+43.32°, wherein 0.0100λ≦G≦0.0500λ, and
• ψ≧167.692°×G/λ+32.435°, wherein 0.0500λ≦G≦0.0695λ,
• wherein, in a case where a relationship of 0.030λ<H≦0.035λ is satisfied, the following relationships are satisfied:
• ψ≦12.0°×G/λ+43.35°, wherein 0.0100λ≦G≦0.0695λ,
• ψ≧45.0°×G/λ+42.80°, wherein 0.0100λ≦G≦0.0500λ, and
• ψ≧186.667°×G/λ+31.217°, wherein 0.0500λ≦G≦0.0695λ.