JP3624797B2 - Temperature control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for fixing a Peltier element when temperature control is performed using a Peltier element, and can be widely applied to temperature control in laser equipment, optical equipment, precision equipment, communication equipment, home appliances, and the like.
[0002]
[Prior art]
For example, Peltier elements are often used for local cooling, relatively small-scale cooling, and temperature control in laser equipment, optical equipment, precision equipment, electronic equipment, communication equipment, home appliances, and the like.
[0003]
As a specific example, for example, a nonlinear optical element such as KNbO ₃ used in a wavelength conversion solid-state laser device has a phase matching condition that changes depending on temperature. It is necessary to control the temperature constantly. In addition, precise temperature control is required for stabilizing the characteristics of the laser oscillation element and stabilizing the interval between the resonator mirrors.
[0004]
A Peltier element is a unit cooling structure that consists of a P-type and N-type Peltier element material having thermoelectric effect through a good electrical and thermal conductor, and one end absorbs heat and generates a heat generation surface depending on the direction of current. Normally, the heat absorption surface is used as a heat sink on the temperature control side and the heat generation surface is used as a contact with the heat sink, but the contact surface between the Peltier element and the heat sink and the contact surface between the Peltier element and the heat sink are good. Thermal contact must be maintained and the thermal resistance at the contact surface must be minimized.
Conventionally, the contact surface between the Peltier element and the heat sink or heat radiator is often bonded and fixed with a heat conductive adhesive, or is tightened with a screw and pressed between the two to be in thermal contact.
[0005]
[Problems to be solved by the invention]
In the method of fixing the Peltier element with a thermally conductive adhesive, the Peltier element and the thermal contact body have a thermal expansion coefficient that causes warpage, resulting in local thermal contact failure or cracks in the Peltier element itself. Damage may occur.
Further, in the method of tightening with a screw, it is difficult to adjust the tightening degree. If the tightening is too loose, the Peltier element may be displaced, and if it is too strong, the Peltier element may be destroyed.
[0006]
For example, when the temperature of an optical system as shown in FIG. 5 is adjusted with a Peltier element, the conventional method (thermally conductive adhesive) causes warpage due to the difference in thermal expansion coefficient between the Peltier element and the base, causing the optical axis to shift. Or the resonator length changes.
An object of the present invention is to solve the above problems and to provide a temperature adjusting device in which the Peltier element is stably fixed.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a temperature adjusting device according to the present invention includes a Peltier element, a heat transfer member that promotes heat conduction from the Peltier element, and a temperature-controlled object that is temperature-controlled by the Peltier element. A temperature comprising: an elastic pressing portion that contacts the heat-adjusting or heat-generating surface of the Peltier element with the object to be temperature-adjusted and elastically presses both of them and does not restrain each other in the contact surface direction. In the adjusting device, the elastic pressing portion is a plate spring and a fixing member that fixes the plate spring to the heat transfer member, or a helical spring, the helical spring, and the temperature-controlled object that penetrates the heat transfer member. The elastic pressing portion is provided at a plurality of locations.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the temperature control device of the present invention will be described.
FIG. 1 shows a basic embodiment of a temperature control device of the present invention, in which a Peltier element 2 is mounted on a flat substrate (base) 1 having good heat conductivity as a heat sink, and further on the Peltier element 2. Further, a Peltier-cooled laminated body 1-2-3 is configured by placing a heat sink 3 having a good thermal conductivity on the flat plate. The surface of the heat sink 3 is pressed by one end of an elastic pressing member 4a for bringing the laminate into close contact with each other, and the other end of the elastic pressing member 4a is fixed to the base 1 by a fixing member 4b. By this elastic pressing portion 4, the both endothermic heat generation surfaces of the Peltier element 2 are pressed and fixed to the heat sink 3 and the base 1, respectively.
[0009]
As the elastic pressing member 4a, a leaf spring having sufficient strength, toughness and elastic modulus is optimal, but a helical spring or the like is also suitable. Moreover, it is also possible to use both together. Further, the magnetic attractive force can be used alone or in combination with the above spring. In FIG. 1, 4b is shown as a simple fixing member, but it is desirable to have an elastic force adjusting mechanism.
[0010]
Although only one elastic pressing portion 4 is shown in FIG. 1, it is desirable to provide a plurality of elastic pressing portions as needed. Thereby, local concentration of the pressing force can be prevented, and the uniformity of the two-dimensional distribution of the pressing force can be improved. For example, several elastic pressing portions 4 may be provided along each side surface of the heat sink 3.
[0011]
Next, specific embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 2 is a schematic configuration diagram of an LD excitation wavelength conversion type solid-state laser device to which the temperature adjusting device of the present invention is applied. In FIG. 2, the optical elements constituting the LD excitation wavelength conversion type solid-state laser device are arranged on the optical axis L in a predetermined positional relationship. Reference numeral 20 denotes a semiconductor laser (laser diode chip, hereinafter referred to as LD chip) serving as an excitation light source, and 21 denotes a condensing optical system for irradiating laser light from the LD chip 20 to the solid-state laser medium. Reference numeral 22 denotes a solid-state laser medium that stimulates and emits fundamental laser light by the irradiation light from the LD chip 20, and uses, for example, Nd: YAG. An HR high reflection coating film 23 is formed on the input side of the solid-state laser medium 22 to totally reflect the fundamental laser beam and its second harmonic (SH wave). Reference numeral 24 denotes a nonlinear optical crystal for generating an SH wave from the fundamental wave output of the solid-state laser medium 22, and for example, KNbO ₃ is used. Reference numeral 25 denotes a wavelength-selective mirror having the characteristics of totally reflecting the fundamental wave and transmitting the SH wave, and the concave mirror surface is coated with the desired wavelength-selective coating. Reference numeral 26 denotes a collimator lens for obtaining a collimated laser beam output having a predetermined shape.
[0012]
The laser beam emitted from the LD chip 20 is focused and irradiated on the solid-state laser medium 22 by the condensing lens 21, and the fundamental wave is stimulated and emitted from the solid-state laser medium 22, and the fundamental wave is reflected by the wavelength selective mirror 25. Then, the HR high reflection coating film 23 of the solid-state laser medium 22 is reflected by the HR high-reflection coating film 23 of the solid-state laser medium 22 by following the same path in reverse. Between these, a laser resonator for the fundamental wave is formed. Then, an SH wave laser beam obtained by wavelength conversion of the fundamental wave from the solid-state laser medium 22 by the nonlinear optical crystal 24 passes through the wavelength selective mirror 25 and is collimated by the collimator lens 26 and emitted.
[0013]
Next, temperature control of the optical system of the LD excitation wavelength conversion type solid-state laser device to which the temperature adjusting device of the present invention is applied will be described. Reference numeral 31 denotes a common base for the LD excitation wavelength conversion type solid-state laser device, which is composed of a smooth metal plate having a sufficient size and strength and good heat conductivity. A Peltier element 32 (32A, 32B) is placed on the base 31, and an optical system base 33 (33A, 33B) is placed on the Peltier element 32 so that the Peltier element 32 is shared with the common base 31. It is elastically pressed and fixed between the optical system base 33 and the optical system by a method described later, and the temperature of the optical system is controlled. As with the common base 31, the optical system base 33 is formed of a smooth metal plate rigid body or the like having good heat conduction, while the base 31 also functions as a heat sink.
[0014]
The Peltier element 32 and the optical system base 33 are divided into relatively small left portions 32A and 33A and comparatively large right portions 32B and 33B as shown in the figure, with a slight gap in the direction of the optical axis L. Arranged. The LD chip 20 is disposed on the left base 33A, and other optical elements 21 to 26 are disposed on the right base 33B. The left and right bases 33A and 33B can be controlled to their own unique temperatures. Become. Accordingly, the temperature of the LD chip 20 is controlled by the Peltier element 32A via the base 33A, and is tuned so as to generate a laser beam having an appropriate wavelength (for example, infrared light having a wavelength of about 860 nm). On the other hand, the nonlinear optical crystal 24 is attached to the Peltier element 32B via the base 33B, and is controlled to a temperature at which the most efficient wavelength conversion is performed.
[0015]
Reference numeral 40 denotes an elastic pressing portion for fixing the Peltier element in the optical system. A side end portion of the base 33A is pressed by one end of a plate spring 41 such as a metal plate having sufficient strength, toughness, and elastic modulus. The leaf spring 41 is formed in a shape that bulges upward, and a through hole (not shown) is provided at the other end, and the upper thread portion of the stepped screw rod 43 fixed to the end surface of the base 31 is this. It is inserted into the through hole. The screw rod 43 has an upper portion formed into a screw and a lower portion formed in a cylindrical shape having a relatively large diameter. By pressing the other end of the leaf spring 41 against an intermediate step stopper portion and tightening the nut 42, The right end portion of the leaf spring 41 is configured to press the base 33A downward with a sufficient pressing force as appropriate, and to fix the Peltier element 32 between the base 31 and the base 33A. The pressing force is stably maintained by the nut 42 and the screw and can be adjusted from time to time as necessary. Although the elastic pressing portion 40 is illustrated only on the left end surface of the base 33A, it is appropriately distributed on each end surface, and the necessary number distribution is similarly installed on the base 33B (detailed in FIG. 4). Describe).
[0016]
In the above configuration, since the thermal contact surface of the Peltier element is not joined by the adhesive, the Peltier element and the thermal contact member are not directly constrained to each other in the contact surface direction. It does not occur that there is a risk of thermal contact failure or damage to the Peltier element. Further, there is no possibility of destroying the Peltier element as in the case of directly tightening with a screw. Therefore, the desired performance can be stably maintained for the entire optical system.
[0017]
3A and 3B show another embodiment of the pressing and fixing portion 40 of the Peltier element. In FIG. 3A, a screw rod 44 is used instead of the screw rod 43 of FIG. A helical spring 45, which is relatively stronger than the leaf spring 41, is installed between the base 41 and the common base 31 so as to surround the screw 44. As a result, the same effects as those in FIG. 2 can be obtained, and the movable range of the nut 42 can be made longer than in the case of FIG. 2 and the adjustment range of the pressing force can be expanded.
[0018]
FIG. 3B shows a hole in which the screw member 48 is fixed to the end of the common base 31 or can be screwed, and the screw member 48 freely passes through the side end of the base 33 for the optical system. And a helical spring 47 having an appropriate strength is inserted between the head 46 of the screw member 48 and the base 33 so as to elastically press the base 31 and the base 33 in the direction of the Peltier element 32. It is a thing. A nut may be used instead of the head portion 46 of the screw member 48. According to the structure of (B), while being able to achieve the function similar to the above-mentioned (A) of FIG. 3 and FIG. 2, it can be made a slightly simpler structure.
[0019]
FIG. 4 shows an embodiment of the arrangement position of the elastic pressing portion 40 in FIGS. You may provide each elastic press part 40A thru | or 40D in the both ends of a longitudinal direction, and 40E thru | or 40H in a side surface. Alternatively, they may be provided together, but in any case, the installation position and installation are such that the arrangement and operation of the optical elements are not hindered and the two-dimensional distribution of the elastic pressing force on the thermal contact surface is as uniform as possible. Select the number.
[0020]
As described above, according to the present invention, it is possible to configure a temperature adjustment device that can fix a Peltier element while maintaining good and stable thermal contact between the Peltier element and the thermal contact member.
In the above-described embodiment, the solid laser medium is excited by the output light from the LD chip, and the nonlinear optical element is disposed in the resonator including the solid laser medium, so that the fundamental light is stimulated and emitted from the solid laser medium. The case where the second harmonic obtained by converting the wavelength of the wave is applied to an LD-pumped solid-state laser device that outputs it to the outside via a wavelength-selective mirror has been described. Can be applied to an optical system or the like of a laser device of a type that obtains a laser beam output of a second harmonic obtained by wavelength conversion by this, and other laser equipment and optical equipment It can be widely applied to temperature control in precision equipment, communication equipment, home appliances and others.
[0021]
【The invention's effect】
According to the present invention, the elastic member can be fixed with a constant force, and at the same time, even when thermally expanded in the thickness direction, the elastic member can be fixed with a constant force, so that no damage due to loosening or excessive tightening occurs. In addition, regarding the thermal expansion in the lateral direction, since the Peltier element is not bonded to the upper and lower materials, it is not necessary to worry about warpage or damage to the element due to the difference in thermal expansion coefficient. In addition, since no adhesive or the like is present on the thermal contact surface, there is almost no thermal resistance on the contact surface.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a temperature adjusting device of the present invention.
FIG. 2 shows a specific embodiment of the temperature adjusting device of the present invention.
FIG. 3 shows another embodiment of the elastic pressing part of the main part of the temperature adjusting device of the present invention.
FIG. 4 shows an arrangement example of a main elastic pressing portion of the temperature adjusting device of the present invention.
FIG. 5 shows an example of a conventional temperature adjusting device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Base 2 ... Peltier element 3 ... Heat sink 4 ... Elastic press part 4a ... Elastic press member 4b ... Fixed member 20 ... LD chip 22 ... Solid laser medium 23 ... HR highly reflective coating film 24 ... Nonlinear optical crystal 25 ... Wavelength selectivity Mirrors 31, 33, 33A, 33B ... bases 32, 32A, 32B ... Peltier element 40 (40A-40H) ... elastic pressing part 41 ... leaf spring 42 ... nuts 43, 44 ... screw rods 45, 47 ... helical spring 48 ... Screw member L ... Optical axis

Claims (2)

A Peltier element, a heat transfer member for promoting heat conduction from the Peltier element, a temperature-controlled object whose temperature is adjusted by the Peltier element, and a heat absorption or heat generation surface of the Peltier element as the temperature-controlled object An elastic pressing portion that is elastically pressed against each other and fixedly held without restraining each other in the contact surface direction. The elastic pressing portion includes a leaf spring and the leaf spring. A temperature adjusting device comprising a fixing member for fixing to a heat transfer member, wherein the elastic pressing portion is provided at a plurality of locations. A Peltier element, a heat transfer member for promoting heat conduction from the Peltier element, a temperature-controlled object whose temperature is adjusted by the Peltier element, and a heat absorption or heat generation surface of the Peltier element as the temperature-controlled object An elastic pressing portion that is elastically pressed against each other and fixedly held without restraining each other in the contact surface direction, wherein the elastic pressing portion is a helical spring and the helical spring And a temperature adjusting device, wherein the elastic pressing portion is provided at a plurality of locations.

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