JPH0226884B2 - - Google Patents

Description

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

(Prior art) Temperature-compensated crystal resonators, which combine a positive characteristic porcelain heating element with self-temperature compensation function and a crystal resonator, have been developed for the purpose of reducing changes in vibration frequency due to changes in ambient temperature of the crystal resonator. Are 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,
For example, when the ambient temperature changes from -30°C to +60°C, the temperature of the crystal resonator will change by 30 to 40°C, and even if it is precisely adjusted, the temperature will change over a temperature range of 10°C or more. The gain (temperature gain = ambient temperature change width/crystal resonator temperature change width) is usually 2 to 3, but even with strict adjustment it is at most 7 to 8.5, so the vibration frequency of the crystal resonator will not change significantly. It was something that would end up happening.

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 small, inexpensive crystal resonator with a large temperature gain.

(Structure of the Invention) The present invention is a small, inexpensive crystal resonator with a large temperature gain that meets these requirements, and is a crystal resonator in which one or more first positive characteristic porcelains are heat-transferably disposed in the crystal resonator. One or more second positive characteristic porcelains electrically connected in series with the first positive characteristic porcelain are thermally attached to the container containing the first positive characteristic porcelain, and electrically connected to the first positive characteristic porcelain and the second positive characteristic porcelain. one or more third
A temperature-compensated crystal oscillator configured such that a positive characteristic porcelain is heat-conductively attached to the container, and the crystal oscillator and the first positive characteristic porcelain are not in direct contact with the second and third positive characteristic porcelains and the container. It is a child.

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 electrically and thermally conductively attached to the outer wall of the metal 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 positive characteristic porcelain 2. The first positive characteristic porcelain 2 and the second positive characteristic porcelain 5 are connected by a connecting wire 6.
are electrically connected in series through the metal case of the crystal resonator. The lid part 7 of the container 3 has a third
The positive characteristic porcelain 8 of
The positive characteristic porcelain is configured electrically in parallel with the series circuit of the first and second positive characteristic porcelains.

The crystal oscillator 1 and the first positive characteristic porcelain 2 are connected to a container 3 in which a second positive characteristic porcelain 5, a third positive characteristic porcelain 8, and a second and third positive characteristic porcelain are attached thermally. Arranged so that there is no direct contact.
The terminals 9, 9' of the crystal resonator 1 are connected to the bottom 4 of the container 3.
One side of the positive characteristic porcelain 5, 8 is electrically insulated from the container and is connected to a terminal 10 which is conductively attached to the metal container. The surface of the first positive characteristic porcelain 2 opposite to the surface attached to the crystal oscillator and the surface of the third positive characteristic porcelain opposite the surface attached to the lid of the metal container are connected to connection wires 11, respectively. , 12 and are electrically insulated from the container and connected to a terminal 13, and the entire container is covered with a heat insulating material 14.

The reason why the first positive characteristic porcelain and the second positive characteristic porcelain are electrically connected in series and the crystal oscillator, the first positive characteristic porcelain, the second positive characteristic porcelain and the container are not brought into direct contact is as follows. When the ambient temperature is low in order to increase the temperature gain of the crystal resonator, when the current is stable after voltage application, the resistance of the first positive characteristic porcelain is greater than the resistance of the second positive characteristic porcelain. Most of the generated voltage is applied to the first positive characteristic porcelain, and the first positive characteristic porcelain becomes the main heating element and directly heats the crystal resonator. The second positive characteristic porcelain senses the heat of the first positive characteristic porcelain and the rise in temperature of the container due to the rise in ambient temperature and increases its resistance.
The ratio of the voltage applied to the positive characteristic porcelain is increased to reduce the amount of heat generated by the first positive characteristic porcelain, thereby reducing the power that the first positive characteristic porcelain directly uses to heat the crystal resonator. At the same time, this is to greatly reduce the overall heat generation amount and increase the temperature gain of the crystal resonator.

When a voltage is applied and the current is stable and 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 characteristic 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.

The reason why the third positive characteristic porcelain is provided electrically in parallel to the series circuit of the first and second positive characteristic porcelain is as follows.
This is to further increase the temperature gain of the crystal resonator achieved by the first and second positive characteristic ceramics,
The reason why the third positive characteristic porcelain is not brought into direct contact with the first positive characteristic porcelain and the crystal oscillator is that if they were in direct contact, mutual thermal interference between the first positive characteristic porcelain and the third positive characteristic porcelain would be too strong. This is because a large temperature gain cannot be obtained.

The size, number, resistance value, Curie temperature, etc. of the third positive characteristic porcelain are appropriately selected so as to correct the temperature characteristic curve of the crystal resonator achieved by the series circuit of the first and second positive characteristic porcelain. It's a good thing.

In order to thermally attach the crystal oscillator and the first positive characteristic porcelain to the container and the second and third positive characteristic porcelain, they may be bonded using a commonly known conductive adhesive; 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-conductive 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.

From an economic point of view, it is preferable to use one piece of each of the first, second, and third positive characteristic porcelains, but a plurality of each may be used. For example, as shown in FIG. 2, two pieces of second positive characteristic porcelain 5,
Alternatively, as shown in FIG. 3, two second positive characteristic porcelains 5, 5' may be attached to the bottom of the container, and three positive characteristic porcelains 8, 8' are attached to the lid. , 8" may be attached. The first positive characteristic porcelain and the second positive characteristic porcelain must be electrically in series with each other, and the third positive characteristic porcelain must be connected to the first and second positive characteristic porcelain. Although it must be parallel to the series circuit of characteristic porcelains, electrically and structurally they may be connected in series or in parallel between each of the first, second, and third positive characteristic porcelains.

The parts of the container to which the second and third positive characteristic porcelains are attached are not limited to the bottom and the lid, but may also be the sides, and the second and third positive characteristic porcelains are attached to the bottom and the lid. There is no need to separate the parts into parts, and in short, any part is sufficient as long as it is easy to assemble and wire, and is easy to thermally design.

The Curie temperatures of the first, second, and third positive characteristic porcelains 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, it is desirable that the Curie temperatures of the second and third positive characteristic porcelains be the same as or 5 to 20° C. lower than the Curie temperatures of the first positive characteristic porcelain. Also, it is preferable that the temperature of the crystal oscillator is normally 70℃ or less, so
It is desirable that the Curie temperature of the positive characteristic porcelain be 70°C or lower, more preferably 50°C or lower.

The material of the container is not limited to metal, and the container may be made entirely or partially of ceramics or resin. Although it is not essential to cover the entire or part of the exterior of the container with a heat insulating material, it is effective to use a heat insulating material to reduce the power required to maintain the crystal resonator at a constant temperature. In addition, the container may have a structure similar to a brewer bottle for heat retention.

(Example) Next, an example will be described.

Example 1 HC-45/U crystal resonator with a diameter of 6 mm and a thickness of 1
mm, the first positive characteristic porcelain with a Curie temperature of 50° C. is adhered with a conductive adhesive, and this is housed in a metal container of 10×15×20 mm. Two pieces of second positive characteristic porcelain of the same size and having a Curie temperature of 40°C are adhered to the bottom of the metal container with a conductive adhesive, and the two second positive characteristic porcelains are electrically paralleled. Connected in series with the first positive characteristic porcelain, a third one of the same size and with a Curie temperature of 40°C
The positive characteristic porcelain is bonded to the lid of the container with a conductive adhesive, and this is connected in parallel with the first and second positive characteristic porcelains. The outer surface of the container was insulated with foamed polystyrene with a thickness of 3 mm, a voltage of 10 V was applied, and its characteristics were measured at ambient temperatures of -30°C to +60°C. Figure 4A
and B, the container temperature ranges from 32°C to 67°C.
℃, the temperature of the crystal resonator was extremely stable from 69.5° to 71.3°C, that is, the temperature gain was 50. In Figure 4A, a shows the temperature change of the crystal resonator, and b shows the temperature change of the container, and Figure 4B shows an enlarged view of the temperature change of the crystal resonator in Figure 4A. It is a graph.

Note that when the same structure was used but the third positive characteristic ceramic was not used, the temperature of the crystal resonator was 61° C. to 68° C., that is, the temperature gain was 12.8.

Example 2 HC-45/U crystal resonator with a diameter of 6 mm and a thickness of 1
mm, the first positive characteristic porcelain with a Curie temperature of 50° C. is adhered with a conductive adhesive, and this is housed in a metal container of 10×15×20 mm. One piece of second positive characteristic porcelain of the same size and having a Curie temperature of 30°C and one of 40°C is glued to the bottom of the metal container with a conductive adhesive, and the two pieces of second positive characteristic porcelain are electrically connected. Connected in parallel and in series with the first positive characteristic porcelain, both of the same size and with a Curie temperature of 30°C.
Three pieces of third positive characteristic porcelain are electrically bonded in parallel to the lid of the container using a conductive adhesive, and this is attached to the first and second pieces of
Connect in parallel with positive characteristic porcelain. The outer surface of the container was insulated with silicone rubber with a thickness of 2 mm, a voltage of 10 V was applied, and its characteristics were measured at an ambient temperature of -30°C to +60°C, as shown in Figure 5 A and B. The temperature ranged from 39°C to 64.5°C, and the crystal resonator temperature ranged from 69.2°C to 72°C, that is, the temperature gain was extremely stable at 32.1. In addition, in FIG. 5A,
a shows the temperature change of the crystal resonator, b shows the temperature change of the container, and Fig. 4B shows the temperature change of the quartz crystal resonator, and Fig. 4B shows the temperature change of the container.
It is a graph showing an enlarged view of the temperature change of the crystal resonator in FIG.

(Effects of the Invention) As described in detail above, the present invention is such that the first positive characteristic porcelain that is thermally attached to the crystal oscillator directly heats the crystal oscillator, and A second positive temperature porcelain connected to the crystal oscillator and a second positive temperature porcelain, which is thermally attached to a container housing the first positive temperature porcelain, senses the ambient temperature and controls the amount of heat generated by the first positive temperature porcelain. Furthermore, the third positive characteristic porcelain connected in parallel with the first and second positive characteristic porcelain acts to compensate the temperature of the container itself with respect to the ambient temperature, so that in Examples 1 and 2, As explained, the temperature of the container housing the crystal resonator is approximately 1/3 of the change in ambient temperature, and the temperature change of the crystal resonator is extremely small, making it possible to easily increase the temperature gain to 20 or more. Furthermore, since the crystal resonator and the first positive characteristic porcelain are not in direct contact with the second and third positive characteristic porcelain and the container, there is no hysteresis in the temperature of the crystal resonator even if the ambient temperature changes. There is no risk that the temperature gain will increase due to variations in the resistance value of positive characteristic porcelain during manufacturing.
The present invention provides a crystal resonator with a simple structure, small size, low cost, and an unprecedented large temperature gain, which is industrially useful.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of one specific example for explaining the configuration of the present invention, FIGS. 2 and 3 are schematic cross-sectional views for explaining another specific example of the present invention, and FIGS.
B and FIGS. 5A and 5B are diagrams showing the performance of the embodiment of the present invention. 1... Crystal resonator, 2... First positive characteristic porcelain,
3... Container, 4... Container bottom, 5, 5'... Second
positive characteristic porcelain, 6... connection wire, 7... lid part, 8,
8', 8''... Third positive characteristic porcelain, 9, 9'... Crystal resonator terminal, 10... Terminal, 11... Connection line, 12... Connection line, 13... Terminal, 14... ...Heat insulation material.

Claims (1)

[Claims] 1 One or more first positive characteristic porcelains are thermally attached to a crystal oscillator, and one or more second positive characteristic porcelains electrically connected in series with the first positive characteristic porcelain are placed in a container for storing the same. A characteristic porcelain is thermally attached to the container, one or more third positive characteristic porcelains electrically connected in parallel with the first and second positive characteristic porcelains are thermally attached to the container, and a crystal oscillator and 1. A temperature-compensated crystal resonator, characterized in that the first positive characteristic porcelain is configured so as not to come into direct contact with the second and third positive characteristic porcelains and the container.