Tuning fork crystal oscillator plate and manufacturing method therefor, and piezoelectric device

A tuning fork crystal oscillator plate, having a base and a pair of vibrating arms extending out of the base, wherein a front surface and a back surface of each vibrating arm are separately provided with step-shaped sinking grooves formed by photolithography and corrosion along a thickness direction, and the photolithography and corrosion are performed on the step-shaped sinking grooves along a length direction of the vibrating arms;

• the step-shaped sinking groove is provided with n steps, and the n steps are formed by n times of photolithography and corrosion, where n is a natural number and is greater than or equal to 2;
• outer surfaces of the step-shaped sinking groove are all plated with electrodes;
• the step-shaped sinking groove comprises a middle step and at least one group of edge steps;
• the number of the middle steps is one, the number of the edge steps is n−1 groups, and each group of the edge steps are two same steps that are symmetrically arranged on two sides of the middle step;
• when one group of edge steps are provided, a width W1 of any one of the edge steps is 5%-40% of a total width W of the steps;
• the total width of the steps is a sum of widths of all the edge steps and a width of the middle step;
• a ratio of a height HI of any one of the edge steps to a height H2 of the middle step is 1:1-1:3;
• when two groups of edge steps are provided, widths of the two groups of edge steps are the same, and a sum of widths of two edge steps on the same side is 28%-32% of the total width W of the steps;
• a height of the two groups of edge steps is the same as that of the middle step;
• when three groups of edge steps are provided, widths of the three groups of edge steps are the same, and a sum of widths of three edge steps on the same side is 28%-32% of the total width W of the steps;
• and a height of the three groups of edge steps is the same as that of the middle step.