JP2537574Y2 - Semiconductor laser module - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a Peltier device using the Peltier effect, and more particularly to a semiconductor laser module.

[Conventional technology]

A Peltier element is an element that utilizes the Peltier effect (a phenomenon in which heat is generated or absorbed other than Joule heat at a contact between different types of conductors when a current flows through the contact), and is mainly used for cooling semiconductor components and the like. What is used.
In particular, in order to cause a semiconductor laser (LD) to emit light stably, cooling by this Peltier element is necessary.

 FIG. 4 shows a Peltier element 11 of this type.

As shown in the figure, the Peltier element 11 connects two different conductors A and B alternately, and has contacts a, b, c,
It is configured such that d and e are alternately up and down.

When a current I flows through the Peltier element 11 from the left side of the figure, heat is absorbed at the upper contacts a, c, and e, and the lower contacts b, d
Generates heat. Note that heat absorption and heat generation are reversed depending on the types of the conductors A and B.

Here, the heat quantity Q generated per unit time at the contact point
(If negative, endothermic), if the current flowing through the contact is I, Q = P _AB · I where P _AB is a Peltier coefficient between conductors A and B.

FIG. 5 is a perspective view showing a planar Peltier device 85 using such a Peltier device 11. As shown in FIG.

As shown in the figure, the planar Peltier element 85 is constituted by arranging a plurality of Peltier elements 11 shown in FIG. 4 in parallel (five in FIG. 4), and sandwiching the upper and lower heat conduction plates 86 and 87. Have been.

When a current I is applied to each Peltier element 11 from one side, one heat conducting plate 86 (or 87) is cooled and the other heat conducting plate 87 (or 86) is heated.

[Problems to be solved by the invention]

By the way, semiconductor laser (LD) and light emitting diode (LE
Many of the elements 90 such as D) and photodiode (PD) are configured in a CAN TYPE as shown in a perspective view in FIG. 6, and have a cylindrical shape.

Therefore, when attaching the planar Peltier element 85 to these cylindrical elements 90, for example, as shown in FIG.
It was necessary to intervene 88. However, with this configuration, there are problems that not only the number of components increases, but also the manufacturing cost increases, and the cooling efficiency of the element 90 deteriorates.

Further, since the planar Peltier element 85 is planar and open to the surrounding space, the heat generated by the planar Peltier element 85 not only transfers to the element 90 but also as shown in FIG. The heat is easily transmitted to the space and escapes, and the heat generated on one surface is easily spilled to the other surface. For this reason, there has been a problem that generated heat is lost.

Further, as shown in FIG. 9, this planar Peltier device
When the object 91 is brought into contact with one surface of the 85, heat flows into and out of the object 91 only from the contact surface with the planar Peltier element 85. Therefore, there is also a problem that a temperature gradient is easily generated inside the object 91.

The present invention has been made in view of the above points, and is a cylindrical Peltier element which is easy to be attached to a cylindrical element, hardly loses generated heat, and hardly generates a temperature gradient inside an object to be cooled and heated. And a semiconductor laser module using the same.

[Means for solving the problem]

In order to solve the above problems, the present invention provides a contact group that generates heat when a current flows in a predetermined direction by alternately connecting conductors made of different materials, and a contact group that absorbs heat. The heat-generating contact group and the heat-absorbing contact group are formed in a cylindrical shape such that one of the groups is inside and the other group is outside, and the conductors are formed on the inner and outer peripheral surfaces of the conductor, respectively. It comprises a cylindrical Peltier element having a heat conduction tube in contact with the contact group, a semiconductor laser, a condenser lens, and an optical isolator, and each of the semiconductor laser, the condenser lens, and the optical isolator has an outer shape. The semiconductor laser, the condenser lens, and the optical isolator were housed in the heat conduction cylinder in a shape substantially the same as the internal shape of the heat conduction cylinder inside the cylindrical Peltier element.

[Action]

By configuring the cylindrical Peltier elements 1 and 8 as described above, a cylindrical object (for example, a semiconductor laser of CAN type)
Can be cooled directly and simply by storing the object inside the cylindrical Peltier elements 1 and 8.

In addition, heat is absorbed (or generated) by the entire inner peripheral surface of the cylinder, and the inner peripheral surface is partially closed. Therefore, the heat loss generated between the outer space and the external space is reduced, and the heat flowing around the outer peripheral surface is reduced.

The object stored in the cylinder is cooled or heated from the entire outer peripheral surface of the object. Therefore, a temperature gradient hardly occurs in the object.

Further, since the surface area of the outer peripheral surface is larger than that of the inner peripheral surface of the cylinder, the heat radiation efficiency is improved.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing a cylindrical Peltier element 1 used in one embodiment of the present invention, wherein FIG. 1 (a) is an exploded perspective view, FIG. 1 (b) is a perspective view, and FIG. FIG.

As shown in FIG. 1, the cylindrical Peltier element 1 is composed of conductors C and D and heat conductive tubes 2 and 3 connected alternately.

Here, the conductor C has a shape in which two cylindrical portions 4 and 5 having different diameters are integrally connected.

The conductor D has the same shape as the conductor C, and has a different diameter.
It has a shape in which two cylindrical portions 6, 7 are integrally connected.

Here, the conductor C and the conductor D are made of different materials so that an effective Peltier effect occurs at the contact point between them.

The heat conducting cylinders 2 and 3 are made of a ceramic or the like having a high heat conduction. The inner diameter of the heat conducting cylinder 2 is almost the same as the outer shape of the cylindrical portions 5 and 6 of the conductors C and D. The outer shape is the conductor C,
It is almost the same as the inner diameter of the cylindrical portions 4 and 7 of D.

The cylindrical Peltier element 1 has a conductor C and a conductor D
Are alternately connected so that their diameters match each other, and then the heat conductive tube 2 is inserted into the outer periphery and the heat conductive tube 3 is inserted into the inner periphery and fixed.

If, for example, a current I is passed in the direction of the arrow shown in FIG. 3C, heat generation (or heat absorption) occurs in the heat conduction cylinder 2 on the outer peripheral side of the cylindrical Peltier element 1, and heat absorption occurs in the heat conduction cylinder 3 on the inner peripheral side. (Or heat).

Next, FIG. 2 is an exploded perspective view showing another embodiment of the present invention.

As shown in the figure, this cylindrical Peltier element 8 has a plurality of Peltier elements 11 shown in FIG. 4 attached in parallel in the axial direction on the outer periphery of a first heat conduction cylinder 9 serving as an inner cylinder. It is manufactured by covering and fixing a second heat conduction cylinder 10 as an outer cylinder on its outer periphery.

Here, the first heat conduction cylinder 9 and the second heat conduction cylinder 10 are both made of ceramic having a high thermal conductivity.

When a current I is applied to the plurality of Peltier elements 11 in, for example, the direction of the arrow shown in the figure, heat is absorbed (or generated) at all the contacts in contact with the first heat conduction cylinder 9 and the second heat conduction cylinder Heat generation (or heat absorption) occurs at all the contacts in contact with 10.

Thereby, the first heat conduction cylinder 9 is cooled (or heated).
Then, the second heat conduction cylinder 10 is heated (or cooled).

FIG. 3 is a schematic side sectional view showing a semiconductor laser module constituted by using these cylindrical Peltier elements 1 or 8.

As shown in FIG.
Immediately before the N-type cylindrical semiconductor laser 20, a condensing lens 21 for collimating the laser light emitted from the semiconductor laser 20 is provided, and before that, an optical isolator 22 for eliminating return light is provided. It is arranged and configured.

The outer circumferences of the semiconductor laser 20, the condenser lens 21, and the optical isolator 22 are formed in a cylindrical shape.

Therefore, each component of the semiconductor laser module can be easily incorporated into the cylindrical Peltier device 1 or 8 according to the present invention.

And by this cylindrical Peltier element 1 or 8,
The temperature of the semiconductor laser 20 and the optical isolator 22 is adjusted.

By the way, in a semiconductor laser module in which the semiconductor laser 20 that generates heat is incorporated, heat is generated only in a very limited part in the module, and there is a possibility that the temperature gradient in the semiconductor laser module becomes large and its characteristics change.

Also, the temperature gradient affects the positional accuracy of each optical component (the positional accuracy of the semiconductor laser module requires an accuracy in the order of μm), and the positional error may degrade the performance of the entire semiconductor laser module.

On the other hand, in the above-mentioned semiconductor laser module, the heat conduction tube 3 is attached to the inner periphery of the cylindrical Peltier element 1 to absorb the heat generated by the semiconductor laser 20, thereby eliminating the temperature gradient of each part of the semiconductor laser module and the entire semiconductor laser module. By keeping the temperature constant, the characteristics of each optical component can be kept constant and the positional accuracy can be kept constant in units of μm.

Therefore, stable light emission of the semiconductor laser 20 can be secured,
In addition, the temperature of the optical isolator 22 and the condenser lens 21 is kept constant, and no displacement occurs in each optical component, so that not only the characteristics of each optical component but also the characteristics of the entire semiconductor laser module are stabilized.

According to the cylindrical Peltier element 1 or 8, heat absorption (or heat generation) occurs on the entire inner peripheral surface of the cylindrical Peltier element 1 or 8, and the inner peripheral surface is semi-sealed. The loss of heat generated between the outer space and the outer space is reduced, and the amount of heat generated on the outer circumferential surface to the inner circumferential surface side is reduced.

On the other hand, since the element housed in the cylindrical Peltier element 1 or 8 is cooled or heated from the entire outer peripheral surface, a temperature gradient hardly occurs in the element.

Further, since the outer peripheral surface has a larger surface area than the inner peripheral surface of the cylindrical Peltier element 1 or 8, the heat radiation efficiency is improved.

Although the embodiment of the cylindrical Peltier device according to the present invention has been described in detail above, the present invention is not limited to this, and various modifications are possible, in short, when a current in a predetermined direction is applied. A Peltier element including a heat-generating contact group and a heat-absorbing contact group, wherein one of the heat-generating contact group and the heat-absorbing contact group is inside and the other group is outside. Any shape and structure may be used as long as it has a structure in which the Peltier element is formed in a cylindrical shape.

[Effect of the invention]

As described in detail above, the semiconductor laser module according to the present invention has the following excellent effects.

Since the outer shapes of the semiconductor laser, the condenser lens, and the optical isolator were all formed to have substantially the same dimensions as the inner shape of the heat conducting tube inside the cylindrical Peltier device, a semiconductor laser or the like was directly placed inside the cylindrical Peltier device. It can be modularized simply by assembling, and not only can its assembly be facilitated, but also the number of parts can be reduced.

Since the heat conduction cylinder was attached to the inner periphery of the cylindrical Peltier element and the contact group contacted the outer periphery of the heat conduction cylinder at the same time, the heat generated by the semiconductor laser contacting the inner periphery of the heat conduction cylinder could be efficiently absorbed and the semiconductor The temperature gradient of each part of the laser module can be eliminated, the temperature of the entire semiconductor laser module can be kept constant, the characteristics of each optical component can be kept constant, and the positional accuracy can be kept constant in μm. Especially, since the semiconductor laser module is an optical component, it is necessary to
Even if the positional error is in the unit of m, its optical characteristics change greatly. Therefore, it is important to cool and equalize the temperature by the cylindrical Peltier element.

Since the inside of the cylindrical Peltier element is in a semi-closed state, heat generated on the outer peripheral surface of the cylindrical Peltier element and heat of the external space hardly affect the inside, heat loss is reduced, and cooling efficiency (or cooling efficiency) is reduced. Heating efficiency) is improved.

The object stored inside the cylindrical Peltier device is
Since the entire outer peripheral surface of the object is cooled or heated, a temperature gradient hardly occurs in the object.

Further, since the outer peripheral surface has a larger surface area than the inner peripheral surface of the cylindrical Peltier element, the heat radiation efficiency is improved.

[Brief description of the drawings]

FIG. 1 is a view showing a cylindrical Peltier element 1 used in one embodiment of the present invention, FIG. 2 is an exploded perspective view showing another embodiment of the present invention, and FIG. Schematic side sectional view showing a semiconductor laser module configured using,
FIG. 4 is a perspective view showing the Peltier element 11, FIG. 5 is a perspective view showing a planar Peltier element 85 using the Peltier element 11, FIG. 6 is a perspective view showing an element 90 such as a semiconductor laser of CAN TYPE. FIG. 7 is a schematic side sectional view showing an example of attaching the planar Peltier element 85 to the element 90, FIG. 8 is a view showing a state of conduction of heat generated by the planar Peltier element 85 to the surrounding space, and FIG. The figure shows an object 91 on one side of a planar Peltier element 85.
FIG. 3 is a diagram showing a temperature state inside the object 91 when the object 91 is brought into contact with the object. In the figure, 1,8 ... cylindrical Peltier element, A, B, C, D ... conductor, I ...
Current.

Claims (1)

(57) [Scope of request for utility model registration] 1. A contact group that generates heat and a heat-absorbing contact group when a current of a predetermined direction is supplied to the conductor by alternately connecting conductors made of different materials, and the heat-generating contact group. And a heat sink that contacts the contact groups on the inner and outer peripheral surfaces of the conductor, respectively. A cylindrical Peltier device having a conductive tube attached thereto, a semiconductor laser, a condenser lens, and an optical isolator, and the outer shapes of the semiconductor laser, the condenser lens, and the optical isolator are all the same as those of the cylindrical Peltier device. A semiconductor laser module, wherein the semiconductor laser module, the condensing lens, and the optical isolator are housed in the heat conduction cylinder, and have the same dimensions as the inner heat conduction cylinder.