JP2003046144A - Package with peltier element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that, when a nylon coated copper wire or an enameled copper wire is used as a lead wire used to connect the current input/ output terminal of a Peltier element to a package, the package is not suitable for fixing a position although it is universal, and that the package is of a structure not suitable for automation. SOLUTION: The package in which an input/output electrode is taken out by using a through hole in a surface or rear surface ceramic substrate for the Peltier element, and in which the height of the position of an internal interconnection or an internal lead is decided so as to match the electrode is prepared, and a structure which is attached uniquely is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION In a laser module used for transmission such as optical communication, a DFB laser is used to obtain a light source with little chirping for the purpose of long-distance transmission. A way to control is taken. The present invention relates to the structure of a package including this Peltier element.

[0002]

2. Description of the Related Art Conventionally, in a laser module used for optical communication or the like, when transmitting a long distance, after passing through a fiber,
To prevent signal deterioration due to various types of dispersion,
It is well known that a laser is used and the temperature is controlled by using a Peltier element in order to secure the stability of wavelength.

The DFB laser is a laser in which a grating is carved into a waveguide layer, light of a narrow wavelength range is returned by this grating, and high-purity single-mode oscillation can be maintained even during high-speed modulation. Therefore, it is less susceptible to the chromatic dispersion of the fiber, and in order to use this characteristic more effectively, the temperature dependence of the wavelength is avoided and the temperature is stabilized by the Peltier element in order to avoid the further influence of the chromatic dispersion.
The wavelength fluctuation is reduced, and it is compatible with long-distance transmission.

This Peltier element utilizes a semiconductor PN junction having the Seebeck effect, and can cool or warm a target surface depending on the direction of the current flowing through the PN junction.

In this Peltier element, a P-type semiconductor and an N-type semiconductor having the Seebeck effect are separately prepared, and the semiconductors are alternately arranged so that one surface has a PN structure.
In addition, the NP structure appears on the other surface, and the above-mentioned effect is obtained by the current flowing through this surface.

FIG. 7 shows a structural diagram of a conventional Peltier element. The p-type elements 12 and the n-type elements 13 are alternately arranged and connected in series by metallization applied to the upper surface ceramic substrate 10 and the lower surface ceramic substrate 11.

This Peltier element is fixed to the ceramic package (not shown) by soldering using the metallization applied to the lower surface of the lower ceramic substrate 11, and utilizing the metallization applied to the upper surface of the upper ceramic substrate 10, The stem to which the laser is attached and the ceramic substrate are attached by soldering.

For the connection for passing a current through the element, a lead 20 provided on the lower surface ceramic substrate 11 of the Peltier element is used, the lead is connected to the electrode portion of the package by soldering, and the current is passed from the lead portion of the package. It will be a matter.

[0009]

The conventional Peltier element is originally used for the purpose of operating the sensor at a low temperature to reduce the thermal noise and for controlling the constant temperature bath. This function is described above.
It has come to be used because it is used for the constant temperature operation of the DFB laser. Therefore, as shown in FIG. 7, a lead 20 is used as the current input / output terminal for general-purpose use. The lead 20 may be a nylon-coated copper wire or an enamel copper wire. is doing.

For this reason, although it has good deformability and has a large tolerance for position fixing, the deformed lead 20 must be housed in the package, and this lead 20 is a terminal for high-speed modulation. It had to be separated from the high-speed modulation terminal because it would combine with and serve as an antenna. As a result, the placement of the leads 20 is limited,
In the end, it puts restrictions on the placement of the entire module,
In addition, in order to prevent noise, there has been a demand for a structure that takes measures such as electrical insulation from the chip carrier on which the laser diode is mounted.

Further, since the lead 20 is easily deformed and it is difficult to take a certain shape, it is not suitable for mounting by using an automatic device, and it is forced to be attached manually.

[0012]

In view of the above, the present invention provides:
The PN junction element is sandwiched between ceramic substrates, and a Peltier element is formed by providing an electrode on the surface of the ceramic substrate opposite to the PN junction element, and the electrode provided on the bottom surface of the package and the electrode of the Peltier element are formed. Abutted and connected directly.

Further, the PN junction element is maintained on the ceramic substrate, and an electrode is provided on the surface of the ceramic substrate opposite to the PN junction element to form a Peltier element. The electrodes were connected with flat or gallowing leads.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a planar structure of a package 1 having a Peltier element 4 according to the present invention. A step is formed inside the package 1, and the internal electrode 3 provided in the step is formed.
And the external lead 2 are connected, and the outer shape is formed by MIM (Metal Injection Molding). A Peltier element 4 is mounted inside the package 1 as shown in the figure. In addition to the metallization 5 for mounting the laser, the Peltier element 4 is provided with an electrode 6 for inputting / outputting a current, and a flat lead 7 is mounted between the electrode 6 and the internal electrode 3 of the package 1. Has been.

By thus forming the internal electrodes 3 on the stepped portions and making the heights of the electrodes 6 uniform, the leads 7 can be easily connected only by placing the Peltier element 4 on the package 1. When the heights of the electrode 6 and the internal electrode 3 do not match, the lead 7 may be of a glowing type and the height may be adjusted.

The purpose of making the lead 7 a flat type or a gallowing type is to prevent lead deformation due to the shape of the lead or the material thereof, so that when the Peltier element is attached to the package 1, automatic assembly is possible. As described above, Kovar or the like is suitable as the material of the lead 7 because it has the purpose of preventing deformation of the lead.

The structure of the Peltier element attached here is shown in FIG. P-type elements 12 and N-type elements 13 are alternately arranged and attached between the upper surface ceramic substrate 10 and the lower surface ceramic substrate 11. Top ceramic substrate 1
On the upper surface of 0, a metallization 5 for attaching a laser element and the like and an input / output terminal electrode 6 are provided, and leads 7 are provided there.
Is attached.

The electrode 6 is attached to the recess and the lead 7
It is also possible to make the upper surface of the upper ceramic substrate 10 and the upper surface substantially flush with each other.

Next, another embodiment of the present invention will be described. First, as shown in FIG. 4 (upside down from FIG. 3),
Input / output electrodes 6 are provided on the lower surface ceramic substrate 11 side of the Peltier element 4 and are connected to the p-type junction element 12 or the n-type junction element 13 through through holes.

As shown in FIG. 2, the package 1 is made of ceramic, and a wiring pattern 8 forming an internal electrode connected to the external lead 2 is formed on the bottom surface of the package 1.

The electrodes 6 and the wiring pattern 8 are aligned with each other, and both are brought into contact with each other to be connected to each other, and this portion is connected by solder, so that the external lead 2 of the package 1 and the Peltier can be connected without using a lead. The element 4 can be connected.

According to the above embodiment, the Peltier element 4
Of the lower surface ceramic substrate 11 not used for connection, and the Peltier element 4 provided in the package 1.
Since the electrode 6 can be surrounded by the electrode used for mounting, the Peltier element 4 is provided with a structure in which all the wirings serving as an antenna are shielded. In the case of the flat type or gallowing type lead 7 shown in FIG. 3, the shielding effect can be improved by using adjacent leads (not shown) to form the feeder. Also,
Since the metallization 5 for mounting the laser element is separated from the others, various parts can be easily mounted.

Next, FIG. 5 shows a superposed view of metallization for mounting the P-type junction element 12 and the N-type junction element 13 of the Peltier element 4. As can be seen from this figure, the upper surface is metallized so that the PN portion is in contact with the lower surface and the NP portion is in contact with the lower surface.

FIG. 6A shows the lower surface of the lower ceramic substrate 1, and FIG. 6B shows the upper surface thereof. The electrode 6 is connected through a through hole 14 to a through hole extraction electrode 17 having a lower surface metallized.

Although the embodiments have been described above, they are summarized as follows.

The electrode 6 for inputting / outputting the p-type junction element 12 and the n-type junction element 13 of the Peltier element 4 is a through hole 14.
Is provided on the surface of the upper ceramic substrate 10 or the lower ceramic substrate 11 on the opposite side of each element.

The input / output electrode 6 and the internal electrode 3 of the package 1 are connected by a flat type or gallowing type 7.

In another form, the input / output electrode 6 and the wiring pattern 8 on the bottom surface of the package 1 are directly brought into contact with each other to be connected to the external lead 2 of the package 1.

The input / output electrodes 6 can be provided with a structure capable of being sufficiently shielded by using the wiring pattern 8 or by using adjacent flat type or glowing type leads (not shown).

[0031]

As described above, according to the present invention, a PN junction element is sandwiched between ceramic substrates, and electrodes are provided on the surface of the ceramic substrate opposite to the PN junction element to form a Peltier element. Since the electrode provided on the inner bottom surface and the electrode of the Peltier element are brought into contact with and directly connected to each other, the Peltier element can be easily attached to the package, and the attachment can be easily automated.

Further, since the space for burying the lead portion is not necessary, it is easy to reduce the package size. Further, by adopting such a structure, the control terminal of the Peltier element is fixed, so that it is possible to easily prevent the coupling between the signal system and the control system.

[Brief description of drawings]

FIG. 1 is a plan view of a package including a Peltier element of the present invention.

2A and 2B show another embodiment of a package including the Peltier element of the present invention, FIG. 2A is a plan view, and FIG. 2B is a sectional view.

FIG. 3 is a perspective view of a Peltier element used in the structure of FIG.

FIG. 4 is a perspective view of a Peltier element used in the structure of FIG.

FIG. 5 is a diagram showing a superposed state of metallization of a Peltier element in the present invention.

6A and 6B show a lower surface ceramic substrate of a Peltier element according to the present invention, FIG. 6A is a plan view of the lower surface, and FIG.
[Fig. 4] is a plan view of the upper surface.

FIG. 7 is a perspective view of a conventional Peltier element.

[Explanation of symbols]

1 package 2 External lead 3 internal electrodes 4 Peltier element 5 Metallization 6 electrodes 7 leads 8 wiring patterns 10 Top ceramic substrate 11 Bottom ceramic substrate 12 P-type junction element 13 N-type junction element 14 through holes 15 Top metallization 16 Lower surface metallization 17 Through-hole extraction electrode

Claims (2)

[Claims] 1. A Peltier element comprising a PN junction element sandwiched between ceramic substrates and an electrode on the surface of the ceramic substrate opposite to the PN junction element to form a Peltier element. A package equipped with a Peltier element, characterized in that it is in direct contact with the electrodes of the element. 2. A Peltier element is formed by maintaining a PN junction element on a ceramic substrate, and an electrode is provided on the surface of the ceramic substrate opposite to the PN junction element, the electrode provided in a package, and the Peltier element. A package equipped with a Peltier element characterized in that the electrodes of are connected by flat type or glowing type leads.