CRYSTAL UNIT
First Claim
1. A crystal unit, comprising:
- an AT-cut crystal element that has a planar shape in a rectangular shape and a part as a thick portion,whereinthe AT-cut crystal element includes a first end portion, a first depressed portion, the thick portion, a second depressed portion, and a second end portion in this order from a side of one short side, in viewing a cross section taken along a longitudinal direction near a center of the short side of the AT-cut crystal element,the first depressed portion is a depressed portion disposed from the thick portion toward a side of the first end portion, and a surface of the first depressed portion is depressed with a predetermined angle θ
a and subsequently bulged, and connected to the first end portion,the second depressed portion is a depressed portion disposed from the thick portion toward a side of the second end portion, and a surface of the second depressed portion is depressed with a predetermined angle θ
b and subsequently bulged, and connected to the second end portion, andwhen a dimension from a distal end of the first end portion to an edge on a side of the second depressed portion of the thick portion is defined as L, the L satisfies a following formula (1),in the formula (1), n is a natural number, and λ
is a wavelength of a flexure vibration that propagates along an X-axis of a crystal in the crystal unit,
L=λ
×
(n/2±
⅛
)
(1).
1 Assignment
0 Petitions
Accused Products
Abstract
A crystal unit includes an AT-cut crystal element that has a planar shape in a rectangular shape and a part as a thick portion. The crystal element includes a first end portion, a first depressed portion, the thick portion, a second depressed portion, and a second end portion in this order from a side of one short side, in viewing a cross section taken along a longitudinal direction near a center of the short side. The first depressed portion is a depressed portion disposed from the thick portion toward the first end portion side, depressed with a predetermined angle θa and subsequently bulged, and connected to the first end portion. The second depressed portion is a depressed portion disposed from the thick portion toward the second end portion side, depressed with a predetermined angle θb and subsequently bulged, and connected to the second end portion.
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Citations
3 Claims
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1. A crystal unit, comprising:
-
an AT-cut crystal element that has a planar shape in a rectangular shape and a part as a thick portion, wherein the AT-cut crystal element includes a first end portion, a first depressed portion, the thick portion, a second depressed portion, and a second end portion in this order from a side of one short side, in viewing a cross section taken along a longitudinal direction near a center of the short side of the AT-cut crystal element, the first depressed portion is a depressed portion disposed from the thick portion toward a side of the first end portion, and a surface of the first depressed portion is depressed with a predetermined angle θ
a and subsequently bulged, and connected to the first end portion,the second depressed portion is a depressed portion disposed from the thick portion toward a side of the second end portion, and a surface of the second depressed portion is depressed with a predetermined angle θ
b and subsequently bulged, and connected to the second end portion, andwhen a dimension from a distal end of the first end portion to an edge on a side of the second depressed portion of the thick portion is defined as L, the L satisfies a following formula (1), in the formula (1), n is a natural number, and λ
is a wavelength of a flexure vibration that propagates along an X-axis of a crystal in the crystal unit,
L=λ
×
(n/2±
⅛
)
(1). - View Dependent Claims (2, 3)
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Specification