JPH0634275U - Ceramic substrate and crystal unit using the same - Google Patents

Abstract

(57) [Summary] The present invention provides a ceramic substrate that can be reliably positioned, and further promotes automation to provide a crystal unit with good characteristics. [Purpose] A structure is provided in which a positioning groove is provided on at least two opposing sides of a rectangular ceramic substrate, or a positioning groove is provided at each corner on at least one diagonal line. Then, a crystal piece is held on such a ceramic substrate to form a crystal resonator.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention has a field of application of a ceramic substrate on which electronic components are mounted, and particularly relates to a ceramic substrate for a crystal unit, which has good positioning accuracy.

[0002]

[Background of device]

 Ceramic substrates are widely used for mounting various electronic components. For example, it is also useful as a substrate for surface mounting in the field of crystal units. In recent years, dimensional accuracy of ceramic substrates has been required for the automation of crystal oscillators.

[0003]

[Prior art]

 FIG. 5 is a diagram for explaining a conventional example of a crystal oscillator. The crystal unit is constituted by holding a crystal piece 2 on a rectangular ceramic substrate 1 and covering a metal cover 3 for example. However, in this example, the crystal piece 2 is held by the supporter 4 at both ends thereof. The ceramic substrate 1 is provided with an electrode 6 serving as an external terminal via a through hole (electrode through hole) 5 to which a supporter 4 is fixed. Usually, a single ceramic green sheet 7 is provided with electrodes 6 including electrode through holes 5 and break lines 8 and integrally fired to form a sheet ceramic substrate 1 (hereinafter referred to as a sheet substrate) (Fig. 6). . Then, along the break line 8, it is divided into individual ceramic substrates 1. In such a case, for example, the ceramic substrate 1 is fitted into the holding hole 11 of the carrier plate 10 (FIG. 7), the carrier plate 10 is advanced, and the supporter 4 and the crystal are sequentially mounted on the ceramic substrate 1. The piece 2 was attached automatically.

[0004]

[Problems of conventional technology]

 However, in the above-mentioned ceramic substrate 1, when the sheet ceramic substrate 9 is divided along the break lines 8, burrs and chips 12 are formed on each side. Therefore, when the ceramic substrate 1 is fitted into the holding hole 11, a gap G more than necessary is generated between the outer circumference of the ceramic substrate 1 and the holding hole 11 (Fig. 8). Then, the ceramic substrate 1 rattles in the holding hole 11, and when the supporter 4 and the crystal piece 2 are mounted by an automatic machine, there is a problem that a positional shift occurs and proper mounting cannot be performed. If it is attached by mistake, it will adversely affect the holding of the crystal blank 2 and hinder the electrical characteristics and impact resistance characteristics.

[0005]

[The purpose of the device]

 It is an object of the present invention to provide a ceramic substrate that can be reliably positioned, and to promote automation thereby to provide a crystal resonator having good characteristics.

[0006]

[Solution]

 The present invention has a basic solution means in which at least one opposing two sides having a rectangular shape are provided with positioning grooves. An embodiment of the present invention will be described below.

[0007]

【Example】

 FIG. 1 is a diagram of a ceramic substrate for explaining an embodiment of the present invention. The same parts as those of the conventional example are given the same numbers to simplify the description. In the ceramic substrate 1, the electrode 6 including the through hole 5 and the break line 8 are provided on the ceramic green sheet 7 as described above. Further, in this embodiment, substantially cross-shaped through holes 13 are provided at each intersection of the break lines 8 corresponding to each corner of the ceramic substrate 1. Then, they are integrally fired to form a sheet ceramic substrate 9, and then divided into individual ceramic substrates 1 along the flake lines 8. That is, the ceramic substrate 1 is configured to have L-shaped positioning grooves 13a at each corner.

With such a configuration, even if the sheet ceramic substrate 9 is divided along the break lines 8, the corners of the ceramic substrate 1 are preliminarily provided with the grooves 13a, so that burrs and chips are not formed. Does not occur. Therefore, as shown in FIG. 3, if each corner is used as a reference surface and is fitted into the holding hole 11 of the carrier plate 10 described above, its positioning is fixed and rattling is prevented. However, the holding hole 11 has an L-shaped corner portion that matches the groove 13 of the ceramic substrate 1, and is set larger than the ceramic substrate 1 except the corner portion. As a result, it is possible to accurately mount the supporter and the crystal piece by the automatic machine. In addition, this makes it possible to maintain good electrical and shock resistance characteristics of the crystal unit.

[0109]

[Other matters]

 In the above embodiment, each corner of the ceramic substrate 1 is L-shaped. However, for example, as shown in FIG. Good. Further, each corner is not limited to the L-shape, and needless to say, may be any corner, and at least one corner may be provided. Further, the groove is not limited to the corner portion, and for example, a groove may be provided on two opposing sides as shown in FIG. What is important is that the outer circumference of the ceramic substrate 1 is provided with a groove that serves as a reference surface that is not affected by the division, and the positioning is assured by this, which is included in the technical scope of the present invention. It is what is done. Although it may be possible to use the electrode through-hole as a positioning, it is not preferable due to its small size and electrical influence. Although the ceramic substrate is used for the crystal unit, it is needless to say that it is not limited to this.

[0010]

[Effect of device]

 Since the present invention is provided with positioning grooves on at least one of two opposing rectangular sides, it is possible to provide a ceramic substrate capable of reliable positioning. Become.

[Brief description of drawings]

FIG. 1 (a) is a plan view of a ceramic green sheet (sheet ceramic substrate) for explaining an embodiment of the present invention,
FIG. 3B is a plan view of the ceramic substrate.

FIG. 2 is a schematic plan view in which a ceramic is mounted on a carrier substrate for explaining the operation according to an embodiment of the present invention.

FIG. 3 is a partial plan view of a ceramic substrate for explaining another embodiment of the present invention.

FIG. 4 is a plan view of a ceramic substrate for explaining another embodiment of the present invention.

FIG. 5 is a cross-sectional view of a crystal resonator for explaining a conventional example.

FIG. 6 is a plan view of a ceramic green sheet (sheet ceramic substrate) for explaining a conventional example.

FIG. 7 is a plan view of a carrier plate for explaining a conventional example.

FIG. 8 is a schematic plan view in which ceramics are mounted on a carrier plate for explaining the operation of the conventional example.

[Explanation of symbols]

1 ceramic substrate, 2 crystal piece, 3 metal cover, 4
Supporters, 5 through holes, 6 electrodes, 7 ceramic green sheets, 8 break lines, 9 sheet ceramic substrates, 10 carrier plates, 11 holding holes, 12 burrs,
Chips, 13 grooves, 14 slopes, 15 grooves.

Claims (3)

[Scope of utility model registration request] 1. A ceramic substrate having a rectangular shape provided with positioning grooves on at least two opposite sides. 2. A ceramic substrate having positioning grooves provided at each corner on at least one diagonal line having a rectangular shape. 3. A crystal resonator comprising a crystal piece held on the ceramic substrate according to claim 1 or 2.