JPH0344450B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Objective of the Invention) The present invention minimizes the temperature change of the crystal resonator in response to changes in ambient temperature, thereby preventing changes in vibration frequency even if the ambient temperature changes. This relates to a crystal resonator that is small, inexpensive, and has a large temperature gain.

(Prior art) Temperature-compensated crystal resonators, which combine a positive characteristic porcelain heating element with a self-temperature compensation function and a crystal resonator, have been developed in order to reduce changes in vibration frequency due to changes in ambient temperature of the crystal resonator. It has been known.

Conventionally known temperature-compensated crystal resonators have a structure in which positive-characteristic porcelain is heat-conductingly attached to the outer wall of a crystal resonator container housing a crystal plate, and the whole is simply housed in a separate container, or a crystal resonator is A structure in which a positive characteristic porcelain is attached to a container that stores the crystal for heat transfer, and a crystal resonator is simply housed in this container, and a structure in which a normal metal wire heating element is wrapped around the crystal resonator and a positive characteristic porcelain is used as a conductor. It is a configuration in which the two are connected thermally and electrically in parallel,
Its characteristics are, for example, when the ambient temperature ranges from -30°C to +60°C.
When the temperature of the crystal oscillator changes to 30 to 40℃,
Even if it is precisely adjusted, the temperature will change in a range of 10℃ or more, so the temperature gain (temperature gain = ambient temperature change width / crystal resonator temperature change width) is usually 2 to 3, and must be adjusted strictly. However, since it is at most 7 to 8.5, the vibration frequency of the crystal resonator changes greatly.

Furthermore, crystal resonators are also known in which a normal heating element is combined with an electronic temperature control mechanism for the purpose of reducing changes in vibration frequency due to ambient temperature of the crystal resonator. Although such a crystal resonator can have a very large temperature gain, it is large and expensive, so it can only be used for specific and limited applications.

For this reason, there has been a strong desire for a crystal resonator that has a large temperature gain, is small, and is inexpensive.

(Structure of the Invention) The present invention is a small, inexpensive crystal resonator with a large temperature gain that meets such demands, and includes a first positive characteristic porcelain attached to the crystal resonator in a thermally conductive manner. A second positive characteristic porcelain is heat-conductively attached to a container that stores this, and the first positive characteristic porcelain and the second positive characteristic porcelain are electrically connected in series via a crystal oscillator. The positive characteristic porcelain and the second positive characteristic porcelain are configured to be separated from each other so as not to come into direct contact with each other, and the terminals of the crystal resonator and the terminals of the positive characteristic porcelain are insulated from the bottom of the container and exposed to the outside. This is a temperature-compensated crystal resonator characterized in that the crystal resonator is derived and fixed in a container.

The structure of the present invention will be explained in detail with reference to FIG. 1, which is a schematic cross-sectional view of one specific example.
A first positive characteristic porcelain 2 is thermally attached to the outer wall of a metallic case, and a second positive characteristic porcelain is attached to the bottom 4 of a metallic container 3 that houses the crystal oscillator 1 and the first positive characteristic porcelain 2. The first positive characteristic porcelain 2 and the second positive characteristic porcelain 5 are electrically connected in series by a connecting wire 6 via the metal case of the crystal resonator. Further, a space is provided so that the crystal resonator 1, the first positive characteristic ceramic 2, and the second positive characteristic ceramic 5 do not come into direct contact. Terminal 7 of crystal oscillator 1,
7' is taken out from the bottom 4 of the container 3 while being electrically insulated from the container, one terminal 8 of the positive characteristic porcelain 2, 5 is connected to the bottom 4 of the metal case, and the other terminal 9 is electrically insulated from the bottom 4 of the container 3. It is insulated and removed.
A heat insulating material 11 is applied to the outer periphery of the lid 10 of the container to keep it warm.

The reason why the first positive characteristic porcelain and the second positive characteristic porcelain are electrically connected in series and the crystal oscillator and the first positive characteristic porcelain and the second positive characteristic porcelain are not brought into direct contact is that the crystal vibration In order to increase the temperature gain of the child, when the ambient temperature is low and the current is stable after voltage is applied, the resistance of the first positive characteristic porcelain is greater than the resistance of the second positive characteristic porcelain, and when the applied voltage is Most of the voltage applied is applied to the first positive characteristic porcelain, and the first positive characteristic porcelain becomes the main heating element,
The crystal oscillator is directly heated, and as the ambient temperature rises, the second positive characteristic porcelain senses the heat of the first positive characteristic porcelain and the temperature rise of the container due to the rise in ambient temperature, and increases its resistance. Then, the ratio of the voltage applied to the second positive characteristic porcelain is increased to reduce the amount of heat generated by the first positive characteristic porcelain, so that the first positive characteristic porcelain directly heats the crystal resonator. This is to reduce the amount of power generated and to greatly reduce the overall amount of heat generated, thereby increasing the temperature gain of the crystal resonator.

When a voltage is applied and the current is stable, when the ambient temperature is low, the first positive characteristic porcelain has a higher resistance than the second positive characteristic porcelain, and becomes the main heating element, and as the ambient temperature increases, the second positive characteristic porcelain In order to increase the resistance of the porcelain and increase the ratio of the voltage applied to the second positive characteristic porcelain, the size, number, resistance value, Curie temperature, and It is important to appropriately select the heat capacity of the crystal resonator and the container, and it is particularly desirable that the heat capacity of the crystal resonator be smaller than the heat capacity of the container.

In order to thermally attach the crystal oscillator and the first positive characteristic porcelain, and to thermally attach the container and the second positive characteristic porcelain, bonding is performed using a commonly known conductive adhesive. Alternatively, a method of soldering, a method of pressing and fixing with a metal spring material, or a method of using a commonly known insulating adhesive or a heat-conducting insulating adhesive may be used. Of course, when an electrically insulating adhesive is used, electrical connection means such as a normal lead wire connection method may be added for mutual electrical connection.

The number of the first positive characteristic porcelain and the second positive characteristic porcelain is preferably one each from the point of view of economy;
A plurality of each may be used. For example, as shown in FIG. 2, the first positive characteristic porcelains 2, 2' may be attached to both sides of the crystal resonator, or as shown in FIG. ’ may be attached. The first positive characteristic porcelain and the second positive characteristic porcelain must be electrically in series with each other, but there is no electrical or structural difference between the first positive characteristic porcelain and the second positive characteristic porcelain. They may be connected in parallel, in series, or in parallel.

The Curie temperatures of the first positive characteristic porcelain and the second positive characteristic porcelain may be the same or different, and should be selected appropriately so that the temperature of the crystal oscillator is not susceptible to changes in ambient temperature. However, preferably, the Curie temperature of the second positive characteristic porcelain is the same as that of the first positive characteristic porcelain, so that the resistance of the second positive characteristic porcelain changes sensitively to changes in ambient temperature. , preferably 5 to 15° C. lower. Furthermore, since the temperature of the crystal resonator is usually preferably 80°C or lower, it is desirable that the Curie temperature of the positive characteristic porcelain be 80°C or lower, more preferably 60°C or lower.

The material of the container is not limited to metal; for example, in FIG. 1, the bottom 4 of the container 3 is made of metal and the lid 10 is made of resin, or the bottom of the container is made of ceramic and the lid 10 is made of resin. Or container 3
The entire container 3 may be made of resin or ceramic, and the entire container 3 or a portion thereof may be combined with a material 11 having good heat retention properties. In addition, the container may have a structure similar to a thermos flask for heat retention. In addition, on the low temperature side of the operating temperature range, in order to make it easier to make the resistance of the first positive characteristic porcelain larger than the resistance of the second positive characteristic porcelain when the current is stable after voltage is applied, the heat capacity of the container is increased by crystallization. It is preferable to make it larger than the heat capacity of the vibrator, so
A heat sink may be added to the second positive characteristic porcelain to increase its heat capacity.

(Example) Next, various embodiments will be described.

Example 1 HC-45/U crystal resonator with a diameter of 6 mm and a thickness of 1
mm, resistance value 20Ω at 25℃, 1st at Curie temperature 30℃
of positive characteristic porcelain is glued with conductive adhesive, and this is
A second positive characteristic porcelain of the same size, the same resistance, and the same Curie temperature is attached to the inner bottom of the metal container with a conductive adhesive, and then the first positive characteristic porcelain is and a second positive characteristic porcelain are connected in series, the outer surface of the container is insulated with foamed silicone rubber with a thickness of 2 mm, a voltage of 13.5 V is applied, and the ambient temperature is -
When the temperature was varied from 30℃ to +60℃ and its characteristics were measured, the resistance of the first positive characteristic porcelain was seven times that of the second positive characteristic porcelain at low temperatures, as shown in Figure 4 a, b, and c. , 0.9 times at +60°C, the temperature of the crystal resonator was 6°C ± 2°C, that is, the temperature gain was 22.5, and the vibration frequency was extremely stable at 0.3 ppm or less.
The power consumption at this time is 0.4W at -30℃ and 0.4W at +60℃.
The power was very low at 0.06W.

If the same structure is used but only the first positive characteristic porcelain is used without using the second positive characteristic porcelain, the temperature of the crystal resonator will be 70℃±5 as shown by the dotted line in Figure 4b.
℃, that is, the temperature gain was as small as 9, and the vibration frequency changed greatly, as shown by the dotted line in FIG. 4c, as much as 1.5 ppm.

Example 2 HC-45/U crystal resonator with a diameter of 8 mm and a thickness of 1
Solder the first positive characteristic porcelain with a resistance of 20Ω at 25°C in mm and a Curie temperature of 35°C, store it in a metal container of 10 x 15 x 20 mm, and place a piece of the same size on the outer bottom of the metal container. A second positive characteristic porcelain with a resistance of 40 Ω at the same Curie temperature of 25°C is soldered, and the first positive characteristic porcelain and the second positive characteristic porcelain are electrically connected in series.
Apply 13.5V voltage, ambient temperature from -30℃ to +60℃
When its characteristics were measured up to ℃, the temperature of the crystal resonator was 65 ⁺⁵ _-2 ℃, or a temperature gain of about 13, which was good.

If the same structure is used, but the first positive characteristic porcelain and the second positive characteristic porcelain are electrically connected in parallel, the temperature will be 75℃.
The center temperature deviated significantly to ⁺¹⁰ _-5 ℃, and the temperature gain decreased to 6.

Example 3 As shown in Fig. 3, a first positive characteristic porcelain with a diameter of 8 mm, a thickness of 1 mm, a resistance of 20Ω at 25°C, and a Curie temperature of 30°C was attached to an HC-45/U crystal resonator using a conductive adhesive. This is then placed in a metal container of 10 x 15 x 20 mm, and two pieces of second positive characteristic porcelain of the same size, the same Curie temperature, and the same resistance are stacked on the inner bottom of the metal container to make it conductive. Attach with adhesive, total of 3
The positive characteristic porcelains were electrically connected in series, and a space of 2 mm was provided between the crystal resonator and the second positive characteristic porcelain. When applying a voltage of 13.5V and changing the ambient temperature from -30℃ to +60℃, we measured the characteristics.
The temperature of the crystal resonator was 63°C±3°C, that is, the temperature gain was 15, which was extremely excellent.

Example 4 On both sides of the HC-43/U crystal resonator, as shown in Figure 2, a resistor of 30 Ω, 8 mm in diameter, 1 mm in thickness, and at 25°C, was placed.
One piece of the first positive characteristic porcelain with a Curie temperature of 35°C is attached using conductive adhesive, the whole is covered with a silicone heat shrink tube, this is stored in a 15 x 20 x 20 mm metal container, and the metal The secondary container has a diameter of 10 mm, a thickness of 1 mm, a resistance of 10 Ω at 25°C, and a Curie temperature of 30°C.
positive characteristic porcelains are soldered, the two first positive characteristic porcelains are electrically connected in parallel, the first positive characteristic porcelain and the second positive characteristic porcelain are electrically connected in series,
By applying a voltage of 13.5V, the ambient temperature ranges from -30℃ to +60℃.
When its characteristics were measured at ℃, the temperature of the crystal resonator was 66±3℃, that is, the temperature gain was 15, which was extremely excellent.

(Effects of the Invention) As described in detail above, the present invention provides that when the ambient temperature is low, the first positive characteristic porcelain that is thermally attached to the crystal oscillator directly heats the crystal oscillator, and As the temperature increases, the second positive characteristic porcelain electrically connected in series with the first positive characteristic porcelain senses the temperature inside the container and the ambient temperature due to the heat of the first positive characteristic porcelain, and increases its resistance. The first positive characteristic porcelain reduces the electric power that directly heats the crystal oscillator and acts to suppress the temperature rise of the crystal oscillator, so even if the ambient temperature changes significantly, the crystal oscillator remains stable. Temperature changes are extremely small, and the temperature gain can easily be 10 or more, and since the crystal resonator and the first positive characteristic porcelain and the second positive characteristic porcelain are not in direct contact, the ambient temperature It has a simple structure, is small, inexpensive, and has a simple structure that eliminates the risk of hysteresis occurring in the temperature of the crystal resonator when the The present invention provides a temperature-compensated crystal resonator with a large temperature gain not found in other countries, and is industrially useful.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of one specific example for explaining the structure of the present invention, FIGS. 2 and 3 are schematic cross-sectional views for explaining another specific example of the present invention, and FIG. FIG. 3 is a diagram showing the performance of an embodiment of the invention. DESCRIPTION OF SYMBOLS 1... Crystal resonator, 2, 2'... First positive characteristic porcelain, 3... Container, 4... Bottom of container, 5, 5'...
...Second positive characteristic porcelain, 6... Connection wire, 7, 7'...
...Terminal of crystal resonator, 8...Terminal of positive characteristic porcelain,
9...Terminal of positive characteristic porcelain, 10...Lid part, 11...
...Heat insulation material.

Claims (1)

[Claims] 1. A first positive characteristic porcelain is thermally attached to a crystal oscillator, a second positive characteristic porcelain is thermally attached to a container for storing it, and the first positive characteristic porcelain and the second positive characteristic porcelain are attached.
positive characteristic porcelain are electrically connected in series via a crystal oscillator, and the first positive characteristic porcelain and the second positive characteristic porcelain are configured to be spaced apart from each other so as not to be in direct contact with each other, 1. A temperature-compensated crystal resonator, characterized in that the crystal resonator is fixed in a container by insulating the terminals of the crystal resonator and the terminals of the positive characteristic porcelain from the bottom of the container and leading them to the outside.