Vibration element, vibrator, oscillator, electronic apparatus, and moving object

Abstract

A vibration element includes a piezoelectric substrate including a vibrating section and a thick section having a thickness larger than that of the vibrating section. The thick section includes a first thick section provided along a first outer edge of the vibrating section, a second thick section provided along a second outer edge, and a third thick section provided along another first outer edge. An inclined outer edge section that intersects with each of an X axis and a Z′ axis is provided in a tip section of the piezoelectric substrate.

What is claimed is: 
     
         1 . A vibration element comprising:
 a substrate that includes a first region having a vibration region that vibrates with a thickness shear vibration, and a second region that is integrated with outer edges of the first region and has a thickness larger than that of the first region, and
 wherein the outer edges of the first region include 
 a first outer edge on one side along a first direction and a first outer edge on the other side, and 
 a second outer edge on one side along a second direction perpendicular to the first direction and a second outer edge on the other side, 
 the first outer edge on the one side being separated from the first outer edge on the other side in the second direction; and 
 the second outer edge on the one side being separated from the second outer edge on the other side in the first direction, 
   wherein the second region includes
 a first thick section that is connected to the first outer edge on the one side, and 
 a second thick section that is connected to the first outer edge on the other side, and wherein: 
   one principal surface of the first thick section projects farther than one principal surface of the first region;   another principal surface of the first thick section projects farther than another principal surface of the first region;   one principal surface of the second thick section projects farther than the one principal surface of the first region;   another principal surface of the second thick section projects farther than the other principal surface of the first region; and   an inclined outer edge section that crosses both the first and second directions is arranged at a corner of the first outer edge side on the other side of the substrate and the second outer edge side on the other side, in a plan view of the substrate.   
     
     
         2 . The vibration element according to  claim 1 ,
 wherein the second region includes a third thick section that is connected to the second outer edge on the other side and is connected to the first and second thick sections;   one principal surface of the third thick section projects farther than the one principal surface of the first region; and   another principal surface of the third thick section projects farther than the other principal surface of the first region.   
     
     
         3 . The vibration element according to  claim 1 , wherein when the length of the substrate along the second direction is L and the length of the first region along the second direction is L 1 , the relationship of L 1 /L≦0.52 is satisfied. 
     
     
         4 . The vibration element according to  claim 1 , wherein, in the plan view of the substrate, when the length of the substrate along the first direction is W, and the length of the first region along the first direction is WI, the relationship of W 1 /W≧0.5 is satisfied. 
     
     
         5 . The vibration element according to  claim 3 , wherein, in the plan view of the substrate, when the length of the substrate along the first direction is W, and the length of the first region along the first direction is W 1 , the relationship of W 1 /W≧0.5 is satisfied. 
     
     
         6 . The vibration element according to  claim 1 , wherein an inclination angle of the inclined outer edge section with respect to the second direction is 40° or greater and 50° or smaller. 
     
     
         7 . The vibration element according to  claim 2 ,
 wherein an inclination angle of the inclined outer edge section with respect to the second direction is 40° or greater and 50° or smaller.   
     
     
         8 . The vibration element according to  claim 3 ,
 wherein an inclination angle of the inclined outer edge section with respect to the second direction is 40° or greater and 50° or smaller.   
     
     
         9 . The vibration element according to  claim 4 ,
 wherein an inclination angle of the inclined outer edge section with respect to the second direction is 40° or greater and 50° or smaller.   
     
     
         10 . The vibration element according to  claim 1 ,
 wherein when a maximum thickness of the second region is Tmax and a minimum thickness thereof is Tmin, an average thickness of (Tmax+Tmin)/2 is 50 μm or greater and 70 μm or smaller.   
     
     
         11 . The vibration element according to  claim 2 ,
 wherein when a maximum thickness of the second region is Tmax and a minimum thickness thereof is Tmin, an average thickness of (Tmax+Tmin)/2 is 50 μm or greater and 70 μm or smaller.   
     
     
         12 . The vibration element according to  claim 3 ,
 wherein when a maximum thickness of the second region is Tmax and a minimum thickness thereof is Tmin, an average thickness of (Tmax+Tmin)/2 is 50 μm or greater and 70 μm or smaller.   
     
     
         13 . The vibration element according to  claim 4 ,
 wherein when a maximum thickness of the second region is Tmax and a minimum thickness thereof is Tmin, an average thickness of (Tmax+Tmin)/2 is 50 μm or greater and 70 μm or smaller.   
     
     
         14 . The vibration element according to  claim 5 ,
 wherein when a maximum thickness of the second region is Tmax and a minimum thickness thereof is Train, an average thickness of (Tmax+Tmin)/2 is 50 μm or greater and 70 μm or smaller.   
     
     
         15 . The vibration element according to  claim 6 ,
 wherein when a maximum thickness of the second region is Tmax and a minimum thickness thereof is Tmin, an average thickness of (Tmax+Tmin)/2 is 50 μm or greater and 70 μm or smaller.   
     
     
         16 . The vibration element according to  claim 1 ,
 wherein the second direction is along the vibration direction of thickness shear vibration.   
     
     
         17 . The vibration element according to  claim 1 ,
 wherein when an electrical axis, a mechanical axis and an optical axis that are crystal axes of a quartz crystal are respectively represented as an X axis, a Y axis and a Z axis, and when an axis obtained by inclining the Z axis so that a +Z side is rotated in a −Y direction of the Y axis is represented as a Z′ axis, using the X axis as a rotation axis, and an axis obtained by inclining the Y axis so that a +Y side is rotated in a +Z direction of the Z axis is represented as a Y′ axis, the substrate is a quartz crystal plate in which a surface including the x axis and the Z′ axis corresponds to a principal surface and a direction along the Y′ axis corresponds to a thickness.   
     
     
         18 . A vibrator comprising:
 the vibration element according to  claim 1 ; and   a package in which the vibration element is accommodated.   
     
     
         19 . An oscillator comprising:
 the vibration element according to  claim 1 ; and   an oscillation circuit that drives the vibration element.   
     
     
         20 . An electronic apparatus comprising the vibration element according to  claim 1 . 
     
     
         21 . A moving object comprising the vibration element according to  claim 1 . 
     
     
         22 . The vibration element according to  claim 5 ,
 wherein an inclination angle of the inclined outer edge section with respect to the second direction is 40° or greater and 50° or smaller.