JPH0732514U - Resonator - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an extremely small resonator that does not require trimming processing such as machining technology and has good detection sensitivity. [Structure] A vibrating body 10 including a weight portion 2 fixed at both ends and a beam 3 is formed on a silicon substrate 1 by utilizing a silicon micromachining technique. A conductive layer 12 as an electrostatic applying means for applying an electrostatic attractive force 15 to the vibrating body 10 is disposed facing the vibrating body with a gap interposed therebetween. By adjusting the electrostatic attractive force 15, the resonance frequency of the vibrating body 10 is adjusted.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a resonator such as a gyro.

[0002]

[Prior art]

 FIG. 3 shows a perspective view of a conventional resonator. The resonator 16 is a resonator 16 of a fine element manufactured by using a conventional silicon micromachining technique or the like. In the figure, a nitride film 7 and a polysilicon film 5 are formed on a silicon substrate 1, and the nitride film 7 and the polysilicon film 5 are fixed to both ends of the silicon substrate 1 by dry etching or the like. A vibrating body 10 composed of the beam 3 and the beam 3 is formed.

Comb-shaped electrodes 6B are formed on both sides of the weight portion 2 at the center of the vibrating body 10 toward the outer side in the lateral direction (direction orthogonal to the beam 3) and face the comb-shaped electrodes 6B. A comb-shaped electrode 6A is arranged at a position, that is, at a position on the side of the polysilicon film 5 on both sides so as to mesh with the comb-shaped electrode 6B toward the inner side in the lateral direction. Driving conductor layers 11A and 11B are connected to the comb-shaped electrodes 6A and 6B, and are connected to an external electrode pad (not shown) via a conductor pattern (not shown) to form the exciter 4. is doing. When an AC voltage is applied to the driving conductor layers 11A and 11B of the exciter 4, an electrostatic force is generated between the comb electrodes 6A and 6B, and the electrostatic force causes the vibrating body 10 including the weight portion 2 and the beam 3 to move in the direction of the arrow. It vibrates in the lateral direction of F (the direction orthogonal to the beam 3).

By driving the comb-shaped electrodes 6A and 6B of the resonator 16 having the above structure, the vibrating body 10 including the weight portion 2 and the beam 3 is vibrated in the lateral direction, and the resonator 16 is rotated about the Z axis. When rotated, a Coriolis force is generated in the direction perpendicular to the plane of FIG. 3, and this Coriolis force is applied to the vibrating body 10 composed of the weight portion 2 and the beam 3, and the vibrating body 10 vibrates in the Coriolis force direction. The magnitude of the angular velocity is detected, for example, by measuring the electrical signal corresponding to the magnitude of the vibration amplitude due to the Coriolis force of the vibrating body 10 at this time.

[0005]

[Problems to be solved by the device]

 By the way, when manufacturing the resonator 16, the frequency in the direction of the Coriolis force of the vibrating body 10 (direction perpendicular to the paper surface) is set to the resonant frequency in advance at the design stage, and the shape, size, weight, etc. of the vibrating body 10 are set. However, the shape, dimensions, weight, etc. of the vibrating body 10 are often not manufactured as designed due to the processing precision of the silicon micromachining technology. Is often deviated from the designed frequency. If the vibration of the vibrating body 10 is in a resonance state, the amplitude is dramatically amplified by the Q (Quality Factor) value due to the structure, but when the frequency is shifted, the amplitude is hardly amplified and the sensitivity of the resonator is remarkably high. There is a problem of decrease. Therefore, it is necessary to trim the weight 2 and the beam 3 by, for example, tedious machining to adjust the resonance frequency of the vibrator 10 to the design set frequency.

However, since the resonator 16 is a fine resonator 16 manufactured by applying a silicon micromachining technique, a fine trimming adjustment necessary for obtaining a desired resonance frequency by using machining. Even if it is attempted to trim a part, it is almost impossible to grind the fine weight portion 2 or the beam 3 into a desired size, shape, weight or the like in terms of processing accuracy by complicated machining. Therefore, it was extremely difficult to adjust the resonance frequency of the resonator 16 to a set value.

The present invention has been made to solve the above-mentioned problems, and an object thereof is to provide an extremely small resonator, which does not require troublesome trimming processing, has a good detection sensitivity, and is excellent in detection sensitivity. Especially.

[0008]

[Means for Solving the Problems]

 The present invention is configured as follows to achieve the above object. That is, the resonator of the present invention oscillates in the direction orthogonal to the length direction of the beam, the weight part arranged in a floating state on the substrate, the beam that supports the weight part from both sides, and the beam part. In a resonator having an exciter, electrostatic applying means for applying an electrostatic bending tension to the vibrating body composed of the weight portion and the beam is arranged opposite to the vibrating body with a gap therebetween. Has been done.

[0009]

[Action]

 Electrostatic applying means for applying electrostatic bending tension is arranged opposite to the vibrating body composed of a weight portion and a beam with a gap interposed therebetween. When this electrostatic applying means is driven to adjust the electrostatic bending tension, the vibrating body is pulled, and the tension tends to increase the frequency of the vibrating body. Thereby, the vibrating body is adjusted to a desired resonance frequency, and the sensitivity of the resonator is increased.

[0010]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the resonator of this embodiment. In the description of the present embodiment, the same names as those in the conventional example are designated by the same reference numerals, and detailed description thereof will be omitted. The resonator 16 of the present embodiment is a resonator of a fine element manufactured by using the silicon micromachining technique or the like as in the conventional example.

The resonator 16 of the present embodiment forms a vibrating body 10 composed of a weight portion 2 and a beam 3 fixed at both ends of a silicon substrate 1 by dry etching or the like, as in the conventional example. On both sides of 10, there are provided exciters 4 utilizing the electrostatic force of the comb-shaped electrodes 6A and 6B which vibrate the weight 2 in a direction orthogonal to the length direction of the beam 3.

The resonator 16 of the present embodiment is characterized in that the vibrating body 10 including the weight portion 2 and the beam 3 which are fixed at both ends and are formed by dry etching of the silicon substrate 1 has a structure shown in FIG. As shown in, the electrostatic applying means for applying the electrostatic attractive force 15 is arranged to face the vibrating body 10 with the gap 9 interposed therebetween. This static electricity applying means is composed of a conductive layer 12 and is connected to a conductive pad 14 via a conductive pattern 13 as shown in FIG.

FIG. 2 shows a manufacturing process of the resonator of this embodiment. First, as shown in (a) of FIG. 2, a nitride film 7 is formed on the outer peripheral side of the silicon substrate 1, and phosphorus (P) or boron (B) is doped in the central portion of the substrate 1 as an electrostatic application means. Forming a conductive layer 12 of. As shown in FIG. 2B, a sacrificial layer 8 such as an oxide film is formed on the conductive layer 12 while straddling the outer peripheral nitride film 7. Next, as shown in FIG. 2C, the polysilicon film 5 is formed on the nitride film 7 and the sacrificial layer 8, and as shown in FIG. 2D, the sacrificial layer 8 is formed by dry etching or the like. Then, the weight portion 2 as a vibrating body is placed facing the conductive layer 12 via the gap 9 so as to be opposed to the conductive layer 12, and the resonator 16 is manufactured.

The resonator 16 of this embodiment does not require trimming of the vibrating body 10, and as shown in FIG. 1, a direct current voltage is applied to the conductive layer 12 via the conductive pad 14 so as to face the conductive layer 12. The vibrating body 10 on the surface is attracted to the substrate 1 side by electrostatic attraction to change the shape of the vibrating body 10 and the resonance frequency of the vibrating body is adjusted to the resonance frequency at the design stage by adjusting the tension. ing. As described above, the electrostatic attraction is adjusted by the electrostatic applying means, and the resonance frequency of the vibrating body 10 is adjusted to the resonance frequency set in advance in the design stage, thereby increasing the sensitivity of the resonator 16. To be

When the exciter 4 of the resonator 16 is driven to vibrate the vibrating body 10 in a direction (horizontal direction) orthogonal to the length of the beam 3 and rotates about the Z axis as a rotation axis, the plane of FIG. A Coriolis force is generated in the direction perpendicular to, and this Coriolis force is applied to the vibrating body 10, and the vibrating body 10 oscillates in the direction of the Coriolis force. By measuring the magnitude of this amplitude, the angular velocity is detected as in the conventional case.

According to the present embodiment, the vibrating body 10 composed of the weight portion 2 and the beam 3 is opposed to the vibrating body 10 via the conductive layer 12 as an electrostatic applying means for applying the electrostatic attractive force 15. Since it is arranged, by adjusting the electrostatic attractive force 15, even with the fine resonator 16 manufactured by the silicon micromachining technology, the resonance frequency of the vibrating body 10 is adjusted to the resonance frequency set in advance in the design stage. The resonator 16 can detect the angular velocity with high sensitivity and high accuracy without being caught by an error generated in the manufacturing process or a change in the usage environment.

The present invention is not limited to the above-mentioned embodiments, and various embodiments can be adopted. For example, in the above-described embodiment, when adjusting the resonance frequency, the tension applying force is formed by pulling the vibrating body 10 toward the substrate 1 side by the electrostatic applying means. However, for example, a voltage having a different polarity is applied to the electrostatic applying means. The resonance frequency may be adjusted by applying an electrostatic repulsive force to the vibrating body 10 and bending the vibrating body 10 in the opposite direction to similarly form tensile tension.

Further, in the above embodiment, the vibrating body 10 including the weight portion 2 and the beam 3 is fixed at both ends in a state of floating on the substrate 1, but the vibrating body 10 is fixed on one side (cantilevered). Beam method) may be used.

Further, although the gyro resonator has been described in the above embodiment, the resonator of the present invention can be applied to other fields besides the gyro.

Furthermore, in the above-described embodiment, the conductive layer 12 serving as the static electricity applying means is provided on the side of the substrate 1 located below the vibrating body 10, but the conductive layer 12 serving as the static electricity applying means vibrates. It may be provided above the body 10 with a gap.

[0021]

[Effect of device]

 According to the present invention, the electrostatic bending means for imparting an electrostatic bending force is arranged opposite to the vibrating body composed of the weight portion and the beam with a gap interposed therebetween so that the electrostatic bending force can be adjusted. By doing so, even a fine resonator manufactured by the silicon micromachining technology can be adjusted to a desired resonance frequency, and this resonator is not affected by errors or changes in the usage environment caused in the manufacturing process. It is possible to detect angular velocity with high sensitivity and high accuracy without being caught.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a resonator of this embodiment.

FIG. 2 is an explanatory diagram of a manufacturing process of the resonator according to the present embodiment.

FIG. 3 is an explanatory diagram of a conventional resonator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Silicon substrate 2 Weight part 3 Beam 4 Exciter 5 Polysilicon film 7 Nitride film 9 Gap 10 Vibrating body 12 Conductive layer as static electricity applying means 15 Electrostatic attractive force between weight part, beam and static electricity applying means

Front page continuation (72) Inventor Kazufumi Moriya, 26-10 Tenjin, Nagaokakyo, Kyoto Prefecture Murata Manufacturing Co., Ltd. Within

Claims (1)

[Scope of utility model registration request] 1. A weight portion arranged in a floating state on a substrate, a beam that supports the weight portion from both sides, and an exciter that vibrates the weight portion in a direction orthogonal to the length direction of the beam. In the resonator having the resonator, electrostatic applying means for applying an electrostatic bending tension to the vibrating body composed of the weight portion and the beam is disposed to face the vibrating body with a gap therebetween.