[0026] The structure and working principle of the present invention will be described in detail below with reference to the accompanying drawings.
[0027] Refer to figure 1 , A low-temperature drift relatively flat-mounted differential integrated resonant accelerometer, comprising a metal base 1 and a first double-ended fixed quartz tuning fork 2-a, a second double-ended fixed quartz tuning fork 2-b, and a metal base 1 It includes a metal base 3, a first flexible hinge 4-a, a second flexible hinge 4-b, a mass 5 and a metal outer frame 6. The mass 5 passes through the first flexible hinge 4-a and the second flexible hinge 4-a. The hinge 4-b is connected to the metal base 3, and the left and right sides and the front side of the metal base 3 are connected to the metal outer frame 6; the first double-ended fixed quartz tuning fork 2-a and the second double-ended fixed quartz tuning fork 2 -b has the same structure, which is mounted on the front and back of the metal base 1, and is arranged in a differential manner. This differential arrangement can reduce the error caused by the thermal stress on the accelerometer and improve the sensitivity of the accelerometer.
[0028] The first flexible hinge 4-a and the second flexible hinge 4-b have elastic characteristics in the sensitive direction SA.
[0029] Refer to figure 2 , The first double-end fixed-end quartz tuning fork 2-a and the second double-end fixed-end quartz tuning fork 2-b are processed by a quartz micromachining process, and include a first fixed base 16-a and a second fixed base at both ends Seat 16-b, the first fixed base 16-a and the second fixed base 16-b are connected with a first fork 17-a and a second fork 17-b, the first fork 17-a and The second fork 17-b is covered with surface electrodes around it, and resonant vibration occurs under the action of the excitation circuit.
[0030] Refer to figure 2 , image 3 , Figure 4 , The metal base 1 is processed with a first boss 7-a and a second boss 7-b on the front side; the metal base 1 is processed with a third boss 7-c and a fourth boss 7-d on the back side; The first boss 7-a and the second boss 7-b are used to fix the first double-ended fixed quartz tuning fork 2-a, and the third boss 7-c and the fourth boss 7-d are used to fix the second Double-ended fixed-end quartz tuning fork 2-b.
[0031] The first boss 7-a is processed with a first semicircular glue overflow groove 8-a, the second boss 7-b is processed with a second semicircular glue overflow groove 8-b, and the third boss A third semicircular glue overflow groove 8-c is machined on 7-c, and a fourth semicircular glue overflow groove 8-d is machined on the fourth boss 7-d, which can prevent unnecessary adhesion in the micro-assembly process The glue is adsorbed on the first tine 17-a and the second tine 17-b of the two double-ended fixed-end quartz tuning forks, which affects the stable resonance of the double-ended fixed-end quartz tuning fork.
[0032] The metal base 1 on both sides and the front side of the first boss 7-a is provided with a first return type overflow groove 9-a, and the metal base 1 on both sides and the rear side of the second boss 7-b is opened with The second type overflow groove 9-b, the third boss 7-c and the front side of the metal base 1 are opened with the third type overflow groove 9-c, the fourth boss 7-d and both sides The metal base 1 on the rear side is provided with a fourth back-shaped overflow groove 9-d. The back-shaped overflow groove is convenient to fit the excess adhesive in the micro-assembly process from the first fixed base of the two double-ended quartz tuning forks. 16-a and the second fixed base 16-b overflow.
[0033] The metal base 1 on the rear side of the first boss 7-a is provided with a first tuning fork movable groove 10-a, and the metal base 1 on the front side of the second boss 7-b is provided with a second tuning fork movable groove. Slot 10-b, the metal base 1 on the rear side of the third boss 7-c is provided with a third tuning fork tine movable groove 10-c, and the metal base 1 on the front side of the fourth boss 7-d is provided with a fourth tuning fork Tooth moving groove 10-d, first tuning fork moving groove 10-a and second tuning fork moving groove 10-b are matched, third tuning fork moving groove 10-c and fourth tuning fork moving groove 10-c The d fit provides sufficient vibration space for the first tine 17-a and the second tine 17-b of the two double-ended fixed quartz tuning forks.
[0034] The metal base 3 is provided with a stress isolation mechanism 11, and the stress isolation mechanism 11 includes a first stress isolation groove 11-a, a second stress isolation groove 11-b, a third stress isolation groove 11-c, and a fourth stress isolation groove 11-a. Slot 11-d. The first stress isolation groove 11-a is located on the front side of the first return type overflow groove 9-a and the third return type overflow groove 9-c, the second stress isolation groove 11-b and the third stress isolation groove 11- c is located on the left and right sides of the first overflow glue groove 9-a and the third glue overflow groove 9-c; the fourth stress isolation groove 11-d is located on the first glue overflow groove 9-a and the third The left and right sides and the back side of the return type overflow groove 9-c; the stress isolation mechanism 11 can reduce the package transmitted to the first double-ended fixed quartz tuning fork 2-a and the second double-ended fixed quartz tuning fork 2-b Stress and thermal stress reduce the temperature drift of the accelerometer and improve the basic accuracy of the accelerometer.
[0035] Both sides of the metal base 3 are provided with a first hinge isolation mechanism 12-a and a second hinge isolation mechanism 12-b, which can reduce the impact of packaging stress and thermal stress on the first flexible hinge 4-a and the second flexible hinge 4-a and the second flexible hinge. The effect of the sex hinge 4-b reduces the output error of the accelerometer.
[0036] The outer right end of the metal outer frame 6 is processed with a first printed circuit adapter board fixing base 13-a, and the outer left end of the metal outer frame 6 is processed with a second printed circuit adapter board fixing base 13-b. The adapter board fixing base can be used to fix the printed circuit adapter board, which facilitates the implementation of the step of pressure-welding gold wires in the micro-assembly process.
[0037] The front side of the metal outer frame 6 is provided with a first gold wire lead groove 14-a, and the back side of the metal outer frame 6 is provided with a second gold wire lead groove 14-b, which is convenient for the gold wire in the micro-assembly process. Lead out.
[0038] The back side of the metal outer frame 6 is processed with a first outer frame fixing seat 15-a, and the front side of the metal outer frame 6 is processed with a second outer frame fixing seat 15-b and a third outer frame fixing seat 15 -c. The three outer frame fixing seats are arranged in a trapezoid shape, which can stably fix the accelerometer in the package shell and reduce the thermal stress of the package shell transmitted to the accelerometer.
[0039] The working principle of the present invention is:
[0040] Due to the inverse piezoelectric effect of the quartz crystal, under the action of the excitation circuit, the first tine 17-a and the second tine 17-b of the double-ended fixed quartz tuning fork covered with electrodes will be in the opposite phase vibration mode When the acceleration acts on the accelerometer along the sensitive direction SA, the first flexible hinge 4-a and the second flexible hinge 4-b drive the mass 5 to produce a displacement in the SA direction, changing the first double-ended fixed quartz tuning fork The resonant frequency of 2-a and the second double-ended fixed quartz tuning fork 2-b can be measured by the peripheral test system to obtain the frequency change value, and the magnitude of the acceleration value can be calculated. The two double-ended fixed-end quartz tuning forks are in a differential arrangement mode. When acceleration is applied, one double-end fixed-end quartz tuning fork is pulled and the resonance frequency becomes larger, and the other double-end fixed-end quartz tuning fork is compressed and the resonance frequency decreases. , The difference between the resonant frequency of the two double-ended fixed quartz tuning forks is used as the output signal of the accelerometer, which can not only reduce the influence of thermal stress on the accelerometer, but also improve the sensitivity of the accelerometer.
[0041] When the thermal stress caused by the environmental temperature change and the packaging stress generated during the packaging process will cause a large error in the output of the accelerometer, the stress isolation mechanism 11 of the metal base 3 is isolated from the first hinge isolation mechanism 12-a and the second hinge. Mechanism 12-b can reduce the influence of thermal stress and packaging stress on the accelerometer, reduce the temperature drift of the accelerometer, and improve the basic accuracy of the accelerometer; the printed circuit adapter board base processed by the metal frame 6 can be used to fix the printed circuit The adapter plate facilitates the implementation of the micro-assembly process; the first outer frame fixing seat 15-a, the second outer frame fixing seat 15-b, and the third outer frame fixing seat 15-c adopt a trapezoidal arrangement, which can reduce the acceleration The meter is stably fixed in the package shell and can reduce the thermal stress of the package shell transmitted to the accelerometer.
