JPH08172315A - Surface mounted type temperature compensated crystal oscillator - Google Patents

Abstract

PURPOSE: To provide a surface mounted type temperature compensated crystal oscillator capable of efficiently and easily adjusting a temperature compensating characteristic and adaptive especially to mass production. CONSTITUTION: Plural mounting electrodes to be surface-mounted are formed on the surface of one side plate and conductive patterns for mounting circuit parts for oscillation circuits are formed on the surface of the other side plate so as to be conducted with the electrodes. The temperature compensated crystal oscillator is provided with a printed wiring board 1 having plural individual patterns 2 each of which is formed by surrounding its outer periphery with a groove 3 and a bridging part 4 to be cut off after adjusting the temperature compensating characteristic, plural temperature compensated crystal oscillation circuits each of which is constituted of mounting circuit parts on each individual pattern 2 formed on the substrate 1 and conductive patterns 6 connected from respective crystal oscillation circuits through the bridging parts 4 to a temperature comensating characteristic measuring instrument through a connection member attachably/detachably formed on the end part of the substrate 1 to output oscillation outputs from respective crystal oscillation circuits.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface-mount type temperature-compensated crystal oscillator which can be easily manufactured and adjusted in temperature compensation characteristics and which is suitable for mass production.

[0002]

2. Description of the Related Art Recently, a crystal oscillator has been widely used as a reference for frequency, time, etc. of various electronic devices. However, such an electronic device is required to have high accuracy as well as small size and light weight. And, as the former means for reducing the size and weight, for example, a surface mounting structure is used.
As the latter means for improving accuracy, temperature compensation is performed to compensate for changes in the oscillation frequency due to temperature changes and maintain a constant oscillation frequency.

In such a temperature-compensated crystal oscillator,
For example, temperature compensation is performed by applying a compensation voltage according to the temperature change between the terminals of the varicap connected in series to the crystal unit, or by connecting a parallel circuit of a capacitor and the thermistor in series with the crystal unit. It is known to perform temperature compensation by utilizing the change in the resistance value of the thermistor due to the change. However, in order to adjust the frequency-temperature characteristic regardless of the structure, the oscillator is housed in a temperature tank and the ambient temperature is set to, for example, −3 depending on the design specification.
It is necessary to confirm the compensation characteristics by changing the range from 0 degree to 60 degrees. However, it takes several hours at the shortest, for example, 3 to 4 hours to carry out such a temperature test, and the capacity of the temperature tank has a great influence on the productivity.

In order to adjust the temperature characteristic as described above, first, the temperature characteristic of the crystal unit itself is measured, and the constant of the temperature compensation circuit corresponding to this characteristic is selected.
A crystal temperature compensation oscillator is assembled by mounting the circuit elements with the selected constants. Then, the assembled oscillator must be put in the temperature tank again to actually change the temperature and confirm the temperature compensation characteristic. In order to measure such temperature compensation characteristics, for example, a jig that has a large number of sockets and can output the oscillation output of the oscillator mounted in each socket to the outside is prepared, and It is necessary to mount a crystal oscillator or a completed crystal oscillator and store it in a temperature tank to control the temperature inside the tank to measure the oscillation frequency at each temperature, which requires a long time for measurement and the object to be measured. It was necessary to replace each one one by one, which was troublesome.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and can adjust the temperature compensation characteristics efficiently and easily, and is a surface mount type temperature compensation crystal suitable for mass production. It is intended to provide an oscillator.

[0006]

According to the present invention, a plurality of mounting electrodes for surface mounting are formed on one side plate surface, and circuit components of an oscillation circuit are mounted on the other side plate surface by being electrically connected to the mounting electrodes. A printed wiring board having a plurality of individual patterns formed by forming a conductive pattern and surrounding the outer periphery with a kerf and a bridging portion cut after adjusting the temperature compensation characteristics, and each individual pattern formed on the printed wiring board. A temperature-compensated crystal oscillation circuit formed by mounting circuit components, and a temperature-compensated crystal oscillation circuit from each temperature-compensated crystal oscillation circuit to the end of the printed wiring board through the bridging portion and a detachable connecting member. And a conductive pattern for deriving an oscillation output of the temperature-compensated crystal oscillation circuit connected to a measuring device.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to a plan view of a printed wiring board shown in FIG. 1 and a side sectional view of a temperature-compensated crystal oscillator shown in FIG. In the figure, reference numeral 1 denotes a printed wiring board having a conductive pattern formed by sticking copper foil on both sides of a plate-shaped glass epoxy or the like and etching the copper foil into a predetermined shape. This printed wiring board 1
In this example, a plurality of individual patterns 2 which are separated after the adjustment of the temperature compensation characteristic are formed in 5 rows and 5 columns, for example. Each of the individual patterns 2 is surrounded by a kerf 3 and four bridging portions 4 at the outer periphery, and the bridging portions 4 are cut so that the individual patterns 2 are separated from the printed wiring board 1 as individual temperature-compensated crystal oscillators. There is. A plurality of mounting electrodes 5 for surface mounting are mounted on one side plate surface of each individual pattern.
A conductive pattern is formed on the other side plate surface of the mounting electrode 5 for mounting a circuit component of the oscillation circuit by conducting through, for example, a through hole. The electrode 5 and the conductive pattern can be formed by etching the copper foil by a known method such as photo etching.

Then, each individual pattern 2 forms a conductive pattern 6 for deriving an oscillation output to the end portion of the printed wiring board 1 via the bridging portion 4, and the conductive pattern 6 is formed.
The card edge connector 7 is formed so that it can be connected to a temperature compensation characteristic measuring device (not shown) through a detachable connecting member at the end of the printed wiring board 1. It should be noted that not only the oscillation output from each individual pattern 2, but also the conductive pattern for supplying the power necessary for driving the oscillation circuit through the bridge portion 4, the conductive pattern of the ground potential, etc. Needless to say, it may be led out to the end of.

Therefore, the semiconductor integrated circuit, the circuit elements 8 such as R and C are formed on the conductive pattern formed in each individual pattern,
For example, the temperature-compensated crystal oscillation circuit is assembled by mounting the crystal oscillator 9 or the like hermetically sealed in a cylindrical metal container. In such a temperature-compensated crystal oscillator, however, it is not always possible to perform temperature compensation as designed due to variations in the temperature characteristics peculiar to individual crystal oscillators, variations in the constants of circuit elements, etc. Absent. Therefore, in the oscillator circuit in which the components are mounted, the end portion of the printed wiring board is connected to the connecting member and put in a temperature chamber, and the temperature is varied to measure the change in the oscillation frequency to measure the temperature compensation characteristic.

As a result of measuring the temperature compensation characteristic, the circuit constant of the circuit element 8 relating to the temperature compensation characteristic is changed or corrected as needed. Such a change or modification of the circuit constant involves, for example, replacing the thermistor with one having different temperature characteristics, increasing or decreasing the resistance value, or replacing the crystal oscillator. Then, after adjusting so as to obtain a temperature compensation characteristic satisfying a predetermined standard, each individual pattern is covered with a cover 10 and sealed. In this case, for example, when the crystal unit is hermetically sealed in a metal container or the like, it is sufficient if the circuit components mounted on the conductive pattern can be mechanically protected, and no particular hermeticity is required. Therefore, the cover 10
Is formed by forming a synthetic resin into, for example, a box shape having an open lower surface, and projecting a convex portion 11 on the lower edge, and forming a through hole at a predetermined position of the individual pattern corresponding to the convex portion to form the convex portion. 11 may be fitted and held. And cover 1 for each individual pattern 2
In the printed wiring board 1 covered with 0, the bridge portion 4 on the outer periphery of each individual pattern 2 is cut by using a cutter to separate the individual temperature compensation oscillators. In this case, each individual pattern 2
Since the outer circumference of is surrounded by the kerf 3 and the bridging portion 4, each individual pattern 2 can be separated from the printed wiring board 1 simply by cutting the bridging portion 4 with a cutter, and the cutting work does not require a particularly large cutting force. And, there is little distortion at the time of cutting,
Moreover, the outer shape of each individual pattern 2 can be accurately maintained.

With such a configuration, the printed wiring board 1 is used for mounting the circuit component 8 on each individual pattern 2, measuring and adjusting the temperature compensation characteristic, connecting and disconnecting the connecting member at the time of putting in and out of the temperature chamber. It can be done as a unit and work can be done efficiently. For example, it is possible to connect a printed wiring board with 25 individual patterns at one time compared to the conventional one in which each oscillator is mounted in a jig socket. improves. Further, since the relatively large printed wiring board 1 can be handled as a unit when mounting or replacing the circuit component 8, the workability can be greatly improved as compared with the case where the individual crystal oscillators are used. For a certain size, there is an advantage that an automatic machine for mounting and soldering can be easily introduced. Also, for the measurement of temperature compensation characteristics,
When the oscillators are put in the temperature tank, the temperature compensation characteristics can be measured by closely stacking them so as not to create useless space. Therefore, when the printed wiring board as in the above embodiment is actually used, the temperature compensation characteristics of, for example, twice as many oscillators as the conventional one can be measured at the same time, and the productivity is remarkably increased. Can be improved. The present invention is not limited to the above-described embodiment, and for example, conductive patterns for deriving an oscillation output and conductive patterns for ground potential may be alternately arranged to enhance isolation between oscillation outputs. Good.

[0012]

As described in detail above, according to the present invention, it is possible to provide a surface-mounted temperature-compensated crystal oscillator that can efficiently and easily adjust temperature compensation characteristics and is particularly suitable for mass production. .

[0010]

[Brief description of drawings]

FIG. 1 is a plan view of a printed wiring board showing an embodiment of the present invention.

FIG. 2 is a side sectional view showing an example of the temperature-compensated crystal oscillator of the present invention.

[Explanation of symbols]

 1 Printed Wiring Board 2 Individual Pattern 3 Grooves 4 Bridging Part 5 Mounting Electrode 7 Card Edge Connector 8 Circuit Parts 9 Crystal Resonator 10 Cover

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Joji Yamashita 2 days at 1275 Kamihirose, Sayama City, Saitama Prefecture Saitama Office

Claims (4)

[Claims] 1. A plurality of mounting electrodes for surface mounting are formed on one side plate surface, and a conductive pattern is formed on the other side plate surface so as to be electrically connected to the mounting electrodes and to mount a circuit component of an oscillation circuit. And a printed wiring board having a plurality of individual patterns formed by being surrounded by a bridging portion that is cut after adjusting the temperature compensation characteristics, and a temperature compensation crystal formed by mounting circuit components on each individual pattern formed on the printed wiring board. Oscillation circuit, and each temperature-compensated crystal from each temperature-compensated crystal oscillator circuit connected to the temperature-compensation characteristic measuring device through a connecting member which is formed from the oscillation circuit to the end of the printed wiring board through the bridge portion. A surface mount type temperature-compensated crystal oscillator, comprising: a conductive pattern for deriving an oscillation output of an oscillation circuit. 2. The surface according to claim 1, wherein conductive patterns of ground potential are respectively arranged between the conductive patterns for deriving the oscillation output of each temperature-compensated crystal oscillator. Mounted temperature compensated crystal oscillator. 3. A surface mount type temperature compensating crystal oscillator according to claim 1, wherein a cover is provided on the other side plate surface of each individual pattern. 4. The surface mount type temperature compensator according to claim 3, wherein a convex portion of the cover is fitted into a through hole formed at a predetermined position of each individual pattern. Crystal oscillator.