Electronic apparatus

a technology of electronic equipment and quartz crystal, applied in the direction of oscillator generators, electrical transducers, transducer types, etc., can solve the problems of inability to achieve a second overtone mode fundamental mode vibration of the resonator, and inability to obtain an electronic apparatus comprising a smaller quartz crystal oscillator, etc., to achieve high frequency stability and high time accuracy

Inactive Publication Date: 2006-11-16
KAWASHIMA HIROFUMI
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AI Technical Summary

Benefits of technology

[0011] The present invention relates to an electronic apparatus comprising a display portion and a quartz crystal oscillator at least, and the quartz crystal oscillator comprises a quartz crystal oscillating circuit having an amplification circuit and a feedback circuit, and in particular, relates to a quartz crystal oscillator having a flexural mode, quartz crystal tuning fork resonator capable of vibrating in a fundamental mode and having an output signal of a high frequency stability for the fundamental mode vibration of the resonator, and also to a quartz crystal oscillator having a suppressed second overtone mode vibration of the flexural mode, quartz crystal tuning fork resonator, in addition, relates to a quartz crystal oscillator comprising a length-extensional mode quartz crystal resonator. The quartz crystal oscillators are, therefore, available for the electronic apparatus requiring miniaturized and low priced quartz crystal oscillators with high time accuracy and shock proof.
[0012] It is an object of the present invention to provide an electronic apparatus comprising a quartz crystal oscillator with a miniature quartz crystal tuning fork resonator, capable of vibrating in a flexural mode, and having a high frequency stability, a small series resistance R1 and a high quality factor Q1, whose nominal frequency for a fundamental mode vibration is within a range of 10 kHz to 200 kHz.
[0013] It is an another object of the present invention to provide an electronic apparatus comprising a quartz crystal oscillator with a flexural mode, quartz crystal tuning fork resonator, capable of vibrating in a fundamental mode, and having a high frequency stability which gives a high time accuracy.

Problems solved by technology

Heretofore, however, it has been impossible to obtain an electronic apparatus comprising a smaller quartz crystal oscillator with a conventional miniaturized quartz crystal tuning fork resonator, capable of vibrating in a flexural mode, and having a high frequency stability, a small series resistance and a high quality factor.
Additionally, for example, there has been a big problem in the conventional oscillator with the conventional quartz crystal tuning fork resonator, such that a fundamental mode vibration of the resonator jumps to a second overtone mode vibration by shock or vibration.
Similarly, however, it has been impossible to obtain an electronic apparatus comprising a smaller quartz crystal oscillator with a conventional length-extensional mode quartz crystal resonator, capable of vibrating in a length-extensional mode, and having a frequency of 1 MHz to 10 MHz, a small series resistance and a high quality factor.
Namely, the resonator has small electromechanical transformation efficiency because the resonator's shape and the electrode construction provide a small electric field, consequently, the resonator has a low frequency stability, a large series resistance and a reduced quality factor when it has the frequency of 1 MHz to 10 MHz.

Method used

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first embodiment

[0050]FIG. 4 shows a general view of a flexural mode, quartz crystal tuning fork resonator 10 which is one of a contour mode resonator, constructing a quartz crystal oscillator, which constructs an electronic apparatus of the present invention and its coordinate system o-xyz. A cut angle θ which has a typical value of 0° to 10° is rotated from a Z-plate perpendicular to the z axis about the x axis. The resonator 10 comprises two tuning fork tines (vibrating tines) 20 and 26 and a tuning fork base (a base) 40. The tines 20 and 26 have grooves 21 and 27 respectively, with the grooves 21 and 27 extending into the base 40. Also, the base 40 has the additional grooves 32 and 36. In addition, the tines 20 and 26 vibrate in a flexural mode of a fundamental mode and an inverse phase.

[0051]FIG. 5 shows a D-D′ cross-sectional view of the tuning fork base 40 of the quartz crystal resonator 10 in FIG. 4. In FIG. 5, the shape of the electrode construction within the base 40 for the quartz crysta...

second embodiment

[0068]FIG. 7 shows a plan view of a flexural mode, quartz crystal tuning fork resonator 45 which is one of a contour mode quartz crystal resonator, constructing a quartz crystal oscillator, which constructs an electronic apparatus of the present invention. The resonator 45 comprises tuning fork tines 46, 47 and a tuning fork base 48. The tines 46, 47 and the base 48 are formed integrally by a chemical etching process. In this embodiment, the base 48 has cut portions 53 and 54. Also, a groove 49 is constructed to include a portion of the central line 51 of the tine 46, and a groove 50 is similarly constructed to include a portion of the central line 52 of the tine 47. In this embodiment, the grooves 49 and 50 are constructed at a part of the tines 46 and 47, and have groove width W2 and groove length l1. In more detail, a groove area S (=W2×l1) has a value of 0.025 mm2 to 0.12 mm2 because it is very easy to form the grooves by a chemical etching process and the quartz crystal tuning ...

third embodiment

[0071]FIG. 8a and FIG. 8b are a top view and a side view for a length-extensional mode quartz crystal resonator which is one of a contour mode resonator, constructing a quartz crystal oscillator, which constructs an electronic apparatus of the present invention. The resonator 62 comprises a vibrational portion 63, connecting portions 66, 69 and supporting portions 67, 80 including respective mounting portions 68, 81. In addition, the supporting portions 67 and 80 have respective holes 67a and 80a. Also, electrodes 64 and 65 are disposed opposite each other on upper and lower faces of the vibrational portion 63, and the electrodes have opposite electrical polarities. Namely, a pair of electrodes is disposed on the vibrational portion. In this case, a fundamental mode vibration can be excited easily.

[0072] In addition, the electrode 64 extends to the mounting portion 81 through the one connecting portion 69 and the electrode 65 extends to the mounting portion 68 through the other conn...

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Abstract

The electronic apparatus comprises a display portion and a quartz crystal oscillator at least, and said electronic apparatus comprises at least one quartz crystal oscillator. Also, the at least one oscillator comprises a quartz crystal oscillating circuit comprising an amplification circuit and a feedback circuit. The feedback circuit is constructed by a flexural mode, quartz crystal tuning fork resonator or a length-extensional mode quartz crystal resonator and for example, the quartz crystal tuning fork resonator comprising tuning fork tines and tuning fork base that are formed integrally, is shown with novel shape and electrode construction. Also, the quartz crystal tuning fork resonator, capable of vibrating in a fundamental mode and having a high frequency stability can be provided with a small series resistance and a high quality factor, even when the tuning fork resonator is miniaturized. In addition, from a relationship of an amplification rate and a feedback rate, an output signal of the quartz crystal oscillating circuit having an oscillation frequency of the fundamental mode vibration for the quartz crystal tuning fork resonator can be provided with the high frequency stability.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a division of copending U.S. patent application Ser. No. 10 / 749,182 filed Dec. 30, 2003 and claiming a priority date of Mar. 6, 2002, which is a continuation-in-part of U.S. patent application Ser. No. 10 / 378,719, filed Mar. 4, 2003, now abandoned.FIELD OF THE INVENTION [0002] The present invention relates to a quartz crystal resonator, a quartz crystal unit having the quartz crystal resonator, a quartz crystal oscillator having the quartz crystal unit, an electronic apparatus comprising at least a display portion and the quartz crystal oscillator, and a method for manufacturing the electronic apparatus. BACKGROUND OF THE INVENTION [0003] There are many electronic apparatuses comprising at least a display portion and a quartz crystal oscillator. For example, cellular phones, wristwatches, facsimiles and pagers comprising a quartz crystal oscillator are well known. Recently, because of high stability for frequency, mi...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): H03H9/21H03H9/10H03H9/215
CPCH03B5/32H03H3/02H03H9/0547H03H9/1021H03H9/215H03H2003/026Y10T29/49004H04R17/00H04R31/00Y10T29/4913Y10T29/49574Y10T29/49005Y10T29/42H03H2003/0492
Inventor KAWASHIMA, HIROFUMI
Owner KAWASHIMA HIROFUMI
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