JP2021168361A - Optical module - Google Patents

Abstract

The present invention provides an optical module in which optical axes of multiplexed light coincide with each other with high precision within a wide temperature range. An optical module (10) includes a support plate (11), a first bonding material (81), an electronic cooling module (70), a second bonding material (82), and a light forming section (13). The light forming section 13 includes a first semiconductor light emitting element, a second semiconductor light emitting element, a filter, and a base part 20 on which the first semiconductor light emitting element, the second semiconductor light emitting element, and the filter are mounted. The electronic cooling module 70 connects the heat sink plate 71 disposed in contact with the first bonding material 81, the heat absorption plate 72 disposed in contact with the second bonding material 82, and the heat dissipation plate 71 and the heat absorption plate 72. A plurality of semiconductor pillars 73 are included. The linear expansion coefficient of the heat sink 71 is 4.0×10 −6 /K or more and 8.0×10 −6 /K or less. When the linear expansion coefficient of the support plate 11 is C1 and the linear expansion coefficient of the heat sink 71 is C2, the relationship between the linear expansion coefficient of the support plate 11 and the linear expansion coefficient of the heat sink 71 is C1<C2. [Selection diagram] Figure 2

Description

The present disclosure relates to optical modules.

A laser module in which a laser element is arranged in a package is known (see, for example, Patent Document 1). Further, a semiconductor module including a heat sink is known (see, for example, Patent Document 2). Such a module is used for various light sources as an optical module that emits light.

Japanese Unexamined Patent Publication No. 2013-7854 Japanese Unexamined Patent Publication No. 2018-182287

The optical module as described above may be used in an environment having a wide temperature range such as low temperature to high temperature. In the optical module, a plurality of semiconductor light emitting elements may be arranged in one package, and the light emitted from the plurality of semiconductor light emitting elements may be combined and output. For such an optical module, it is desired to align the optical axes of the light that is combined in a wide temperature range with high accuracy.

Therefore, one of the purposes is to provide an optical module in which the optical axes of the combined light within a wide temperature range match with high accuracy.

The optical module according to the present disclosure includes a support plate, a first bonding material arranged on the support plate, and an electronic cooling module arranged on the first bonding material and bonded to the support plate by the first bonding material. , A second bonding material arranged on the electronic cooling module, and a light forming portion configured to form light, arranged on the second bonding material, and bonded to the electronic cooling module by the second bonding material. To be equipped with. The light forming unit emits light from a first semiconductor light emitting element, a second semiconductor light emitting element that emits light having a second wavelength different from the first wavelength, and a first semiconductor light emitting element. A filter that combines the light of the first wavelength and the light of the second wavelength emitted from the second semiconductor light emitting element is arranged in contact with the second bonding material, and the first semiconductor light emitting element, the first 2 Includes a base portion on which a semiconductor light emitting element and a filter are mounted. The electronic cooling module includes a heat radiating plate arranged in contact with the first joining material, a heat absorbing plate arranged in contact with the second joining material, and a plurality of semiconductor columns connecting the heat radiating plate and the heat absorbing plate. include. The coefficient of linear expansion of the heat sink is 4.0 × ^10-6 / K or more and 8.0 × ^10-6 / K or less. Assuming that the coefficient of linear expansion of the support plate is C ₁ and the coefficient of linear expansion of the heat radiating plate is C ₂ , the relationship between the coefficient of linear expansion of the support plate and the coefficient of linear expansion of the heat radiating plate is C ₁ <C ₂ .

According to the above optical module, the optical axes of the light that is combined in a wide temperature range can be aligned with high accuracy.

FIG. 1 is an external perspective view showing the structure of the optical module according to the first embodiment. FIG. 2 is an external perspective view showing a state in which the cap of the optical module shown in FIG. 1 is removed. FIG. 3 is a plan view of the optical module with the cap shown in FIG. 2 removed. FIG. 4 is a side view of the optical module with the cap shown in FIG. 2 removed. FIG. 5 is a side view of the optical module with the cap shown in FIG. 2 removed. FIG. 6 is a graph showing the deviation of the optical axis when the coefficient of linear expansion of the support plate is 5.2 × 10 ^{-6 / K.} FIG. 7 is a graph showing the deviation of the optical axis when the coefficient of linear expansion of the support plate is 10.0 × ^{10-6 / K.} FIG. 8 is a graph showing the deviation of the optical axis when the coefficient of linear expansion of the support plate is 3.7 × 10 ^{-6 / K.} FIG. 9 is a graph showing the deviation of the optical axis when the linear expansion coefficient of the support plate is 1.0 × ^{10-6 / K.} FIG. 10 is a graph showing the deviation of the optical axis when the linear expansion coefficient of the support plate is 0.1 × ^{10-6 / K.}

[Explanation of Embodiments of the present disclosure]
First, embodiments of the present disclosure will be listed and described. The optical modules are on the support plate, the first bonding material arranged on the support plate, the electronic cooling module arranged on the first bonding material and bonded to the support plate by the first bonding material, and the electronic cooling module. It is provided with a second bonding material arranged in the above, and a light forming portion configured to form light, arranged on the second bonding material, and bonded to the electronic cooling module by the second bonding material. The light forming unit emits light from a first semiconductor light emitting element, a second semiconductor light emitting element that emits light having a second wavelength different from the first wavelength, and a first semiconductor light emitting element. A filter that combines the light of the first wavelength and the light of the second wavelength emitted from the second semiconductor light emitting element is arranged in contact with the second bonding material, and the first semiconductor light emitting element, the first 2 Includes a base portion on which a semiconductor light emitting element and a filter are mounted. The electronic cooling module includes a heat radiating plate arranged in contact with the first joining material, a heat absorbing plate arranged in contact with the second joining material, and a plurality of semiconductor columns connecting the heat radiating plate and the heat absorbing plate. include. The coefficient of linear expansion of the heat sink is 4.0 × ^10-6 / K or more and 8.0 × ^10-6 / K or less. Assuming that the coefficient of linear expansion of the support plate is C ₁ and the coefficient of linear expansion of the heat radiating plate is C ₂ , the relationship between the coefficient of linear expansion of the support plate and the coefficient of linear expansion of the heat radiating plate is C ₁ <C ₂ .

The optical module is configured by mounting an electronic cooling module (hereinafter, may be referred to as a TEC (Thermo-Electric Cooler)) on a support plate and mounting a light forming unit on the TEC. On the base portion included in the light forming portion, the light of the first wavelength emitted from the first semiconductor light emitting element, the second semiconductor light emitting element, the first semiconductor light emitting element, and the second semiconductor light emitting element were emitted. A filter that combines light of a second wavelength is installed. The temperature of the base portion is adjusted by TEC to keep the temperature of the light forming portion constant. In an optical module that combines and outputs a plurality of lights, the present inventors align the optical axes of light emitted from a plurality of semiconductor light emitting elements at a certain temperature, for example, room temperature, and output the combined waves. However, we focused on the fact that if there is a change in the ambient temperature, it is difficult to accurately match the optical axes of multiple combined lights. Specifically, for example, when the environmental temperature at which the optical module is installed becomes high, each member constituting the optical module thermally expands. Then, the warp of the entire optical module occurs due to the difference in the coefficient of linear expansion between the members. For example, even if the optical axes of a plurality of lights are aligned at room temperature, the effect of this warp results as a result. The optical axes of the plurality of light to be combined will be shifted. Here, the present inventors have conducted diligent studies, and instead of trying to reduce the amount of warpage of the entire optical module at the time of temperature change by aligning the linear expansion coefficients of each member constituting the optical module as much as possible, the optical axis. Focusing on the adjustment of the warp of the base part due to the displacement, it was possible to match the optical axis of the combined light with high accuracy even within a wide temperature range.

In the optical module of the present disclosure, an optical axis of light having a first wavelength emitted from a first semiconductor light emitting device and light having a second wavelength emitted from a second semiconductor light emitting device at a predetermined temperature, for example, room temperature. Adjust so that it matches the optical axis of. Here, the coefficient of linear expansion of the heat sink is 4.0 × ^10-6 / K or more and 8.0 × ^10-6 / K or less. Therefore, even if the environmental temperature in which the optical module is arranged changes significantly, the warp of the heat sink against the temperature change can be suppressed within a certain range. Further, the linear expansion coefficient of the support plate and C _1, when the linear expansion coefficient of the heat sink and C _2, the relation between the linear expansion coefficient of the heat radiating plate and the linear expansion coefficient of the support plate, are C 1 _{<C 2} .. That is, the coefficient of linear expansion of the support plate is made smaller than the coefficient of linear expansion of the heat sink. When the temperature changes, the heat sink and the support plate tend to warp due to the temperature change, but since the heat sink is joined to the support plate by the first bonding material, it warps based on the linear expansion coefficient of the support plate. Due to the influence of the support plate, the amount of warpage of the heat sink can be reduced. Therefore, when the temperature changes, it is possible to suppress the warp of the base portion bonded to the TEC including the heat radiating plate via the second bonding agent. Therefore, it is possible to suppress the deviation of the optical axis due to the change in the relative positional relationship between the first semiconductor light emitting element, the second semiconductor light emitting element, and the filter mounted on the base portion. As a result, the optical axes of the light that is combined in a wide temperature range can be matched with high accuracy.

In the above optical module, the relationship between the linear expansion coefficient of the support plate and the linear expansion coefficient of the heat radiating plate may be _{C 1} <0.7 × C _2. By doing so, it is possible to match the optical axes of the light that is combined in a wide temperature range with higher accuracy.

In the above optical module, the relationship between the linear expansion coefficient of the support plate and the linear expansion coefficient of the heat radiating plate may be _{C 1} <0.5 × C _2. The optical axis of the light that is combined in a wide temperature range can be matched with higher accuracy.

In the above optical module, the relationship between the linear expansion coefficient of the support plate and the linear expansion coefficient of the heat radiating plate may be 0.1 × C ₂ <C ₁ <0.5 × C ₂ . By doing so, it is possible to match the optical axes of the light that is combined in a wide temperature range with higher accuracy.

In the above optical module, the first bonding material may be a silver paste in which silver particles are dispersed in a resin binder. Since the silver paste has a relatively low curing temperature, it is possible to reduce the generation of thermal stress during curing. In addition, since the silver paste has elasticity to some extent, the warp of the heat radiating plate caused by the difference between the linear expansion coefficient of the support plate and the linear expansion coefficient of the heat radiating plate is allowed by the deformation of the silver paste itself when the temperature changes. can do. Therefore, the reliability of the optical module can be improved.

In the above optical module, the material of the support plate may be SiC or Kovar. The material of the heat sink may be alumina. By making the material of the support plate and the material of the heat radiating plate in this way, it is possible to more reliably match the optical axes of the light to be combined in a wide temperature range with high accuracy.

[Details of Embodiments of the present disclosure]
Next, an embodiment of the optical module of the present disclosure will be described with reference to the drawings. In the following drawings, the same or corresponding parts are designated by the same reference numerals, and the description thereof will not be repeated.

(Embodiment 1)
The optical module according to the first embodiment of the present disclosure will be described. FIG. 1 is an external perspective view showing the structure of the optical module according to the first embodiment. FIG. 2 is an external perspective view showing a state in which the cap of the optical module shown in FIG. 1 is removed. FIG. 3 is a plan view of the optical module with the cap shown in FIG. 2 removed. FIG. 3 is a view of the optical module shown in FIG. 2 as viewed in the thickness direction of the support plate. 4 and 5 are side views of the optical module with the cap shown in FIG. 2 removed. FIG. 4 is a side view when viewed in the X direction. FIG. 5 is a side view when viewed in the Y direction. In FIG. 3, the optical axis is indicated by a broken line.

With reference to FIGS. 1 to 5, the optical module 10 according to the first embodiment is arranged on a support plate 11 having a flat plate shape and one surface 12A of the support plate 11 so as to form light. A light forming unit 13 as a light forming unit to be configured, a cap 14 arranged in contact with one surface 12A of the support plate 11 so as to cover the light forming unit 13, and the other surface 12B of the support plate 11. It is provided with a plurality of lead pins 16 that penetrate from the side to one surface 12A side and project to both sides of one surface 12A side and the other surface 12B side. The support plate 11 and the cap 14 are made airtight by being welded, for example. That is, the light forming portion 13 is hermetically sealed by the support plate 11 and the cap 14. The space surrounded by the support plate 11 and the cap 14 is filled with a gas having reduced (removed) moisture such as dry air. The cap 14 is formed with an exit window 15 coated with an AR (Anti Reflection) coating made of glass that transmits light from the light forming portion 13. When viewed in a plane (when viewed in the Z direction), the support plate 11 has a rectangular shape with rounded corners. The cap 14 also has a rectangular shape with rounded corners when viewed in a plane.

The light forming portion 13 includes a base plate 20 having a plate-like shape as a base portion. The base plate 20 has one surface 21A having a rectangle and the other surface 21B located on the opposite side of the one surface 21A in the thickness direction when viewed in the thickness direction of the support plate 11. The direction in which the long side of the base plate 20 extends is the same as the direction in which the long side of the support plate 11 extends (X direction). The direction in which the short side of the base plate 20 extends is the same as the direction in which the short side of the support plate 11 extends (Y direction). The surface 21A includes a chip mounting area 22 and a base area 23. The thickness of the chip mounting area 22 is larger than that of the base area 23. As the material of the base plate 20, for example, iron or copper is selected.

A flat plate-shaped first submount 31, a flat plate-shaped second submount 32, and a flat plate-shaped third submount 33 are formed on the chip mounting region 22, respectively. A red laser diode 41, which is a first semiconductor laser as a first semiconductor light emitting element, is arranged on the first submount 31. A green laser diode 42, which is a second semiconductor laser as a second semiconductor light emitting element, is arranged on the second submount 32. A blue laser diode 43, which is a third semiconductor laser as a third semiconductor light emitting element, is arranged on the third submount 33. The red light is the light of the first wavelength. The green light is light having a second wavelength different from that of the first wavelength. The blue light is light having a third wavelength different from that of the first wavelength and the second wavelength. The red light emitted from the red laser diode 41, the green light emitted from the green laser diode 42, and the blue light emitted from the blue laser diode 43 are parallel to each other in the Y direction. Is. A thermistor 17 for measuring the temperature of the light forming unit 13 is mounted on the chip mounting region 22. The thermistor 17 is attached to the side of the third submount 33 at intervals from the blue laser diode 43.

In the base region 23, a first lens 51, a second lens 52, and a third lens 53 each having a lens surface are arranged. That is, the base plate 20 is mounted with the first lens 51, the second lens 52, and the third lens 53. The central axes of the first lens 51, the second lens 52, and the third lens 53, that is, the optical axes of the respective lens surfaces coincide with the optical axes of the red laser diode 41, the green laser diode 42, and the blue laser diode 43, respectively. It has been adjusted to. The process of adjusting the optical axis, that is, attaching the first lens 51, the second lens 52, and the third lens 53 to the base region 23 by aligning the optical axes, is performed at a predetermined temperature, for example, at room temperature such as 25 ° C. It is said.

The first lens 51, the second lens 52, and the third lens 53 change the spot size of the light emitted from the red laser diode 41, the green laser diode 42, and the blue laser diode 43, respectively. The first lens 51, the second lens 52, and the third lens 53 are respectively adhered to the base region 23 with, for example, an ultraviolet curable adhesive.

A first filter 61, a second filter 62, and a third filter 63 are arranged in the base region 23. The first filter 61, the second filter 62, and the third filter 63 are respectively adhered to the base region 23 with, for example, an ultraviolet curable adhesive. The first filter 61, the second filter 62, and the third filter 63 are, for example, wavelength selective filters. The first filter 61, the second filter 62, and the third filter 63 are dielectric multilayer filters. Specifically, the first filter 61 reflects red light. The second filter 62 transmits red light and reflects green light. The third filter 63 transmits red light and green light, and reflects blue light. The main surfaces of the first filter 61, the second filter 62, and the third filter 63 are inclined in the emission direction of the light emitted from the red laser diode 41, the green laser diode 42, and the blue laser diode 43, respectively. Specifically, the main surfaces of the first filter 61, the second filter 62, and the third filter 63 are directed with respect to the emission directions of the light emitted from the red laser diode 41, the green laser diode 42, and the blue laser diode 43, respectively. It is tilted 45 °. As a result, the first filter 61, the second filter 62, and the third filter 63 combine the light emitted from the red laser diode 41, the green laser diode 42, and the blue laser diode 43.

The optical module 10 includes a TEC 70 that adjusts the temperature of the light forming unit 13. The TEC 70 is arranged between the light forming portion 13 and the support plate 11. The TEC 70 is a Perche module (Pelche element), and includes a heat radiating plate 71, a heat absorbing plate 72, and a plurality of columnar semiconductor columns 73 connecting the heat radiating plate 71 and the heat absorbing plate 72. The plurality of semiconductor columns 73 are arranged side by side with a space between the heat radiating plate 71 and the heat absorbing plate 72, and the temperature of the base plate 20 is adjusted by the TEC 70 so that the temperature of the light forming portion 13 is constant. For example, it is kept at 35 ° C.

The optical module 10 includes a first joining member 81 arranged on the support plate 11. The support plate 11 and the TEC 70 are joined by the first joining material 81. The first joining member 81 is arranged between the support plate 11 and the TEC 70. The heat radiating plate 71 included in the TEC 70 is arranged in contact with the first joining member 81. As the first bonding material 81, for example, a silver paste in which silver particles are dispersed in a resin binder is used. The silver paste can be cured at a relatively low temperature, for example, about 100 ° C.

The optical module 10 includes a second bonding material 82 arranged on the TEC 70. The TEC 70 and the base plate 20 are joined by the second joining material 82. The second joining material 82 is arranged between the TEC 70 and the base plate 20. The endothermic plate 72 included in the TEC 70 is arranged in contact with the second joining member 82. As the second joining material 82, for example, silver paste is used as in the case of the first joining material 81.

By supplying an electric current to the TEC 70 and passing an electric current, the heat of the base plate 20 joined to the endothermic plate 72 is transferred to the support plate 11 side, and the base plate 20 is cooled. As a result, the temperature rise of the red laser diode 41, the green laser diode 42, and the blue laser diode 43 can be suppressed. That is, by providing the TEC 70, the temperatures of the red laser diode 41, the green laser diode 42, and the blue laser diode 43 can be adjusted and the output can be stabilized.

Here, the coefficient of linear expansion of the heat radiating plate 71 is 4.0 × 10 ^-6 / K or more and 8.0 × 10 ^-6 / K or less. Further, assuming that the coefficient of linear expansion of the support plate 11 is C ₁ and the coefficient of linear expansion of the heat radiation plate 71 is C ₂ , the relationship between the coefficient of linear expansion of the support plate 11 and the coefficient of linear expansion of the heat radiation plate 71 is C ₁ <. It is C _2. Specifically, for example, the material of the support plate 11 is Kovar. The coefficient of linear expansion of Kovar is 5.2 × ^10-6 / K. The material of the heat radiating plate 71 is alumina (Al ₂ O ₃ ). The coefficient of linear expansion of alumina is 7.7 × ^10-6 / K. The material of the endothermic plate 72 is also alumina. That is, the material of the plate-shaped member constituting the TEC 70 is alumina. Further, as a material of the semiconductor column 73, for example, BiTe can be mentioned.

In the optical module 10, even if the environmental temperature in which the optical module 10 is arranged changes significantly, the warp of the heat radiating plate 71 with respect to the temperature change can be suppressed within a certain range. The relationship between the coefficient of linear expansion of the support plate 11 and the coefficient of linear expansion of the heat sink 71 is C ₁ <C ₂ . When the temperature changes, the heat radiating plate 71 and the support plate 11 tend to warp due to the temperature change, but since the heat radiating plate 71 is joined to the support plate 11 by the first joining material 81, the linear expansion of the support plate 11 The amount of warpage of the heat radiating plate 71 can be reduced due to the influence of the support plate 11 that warps based on the coefficient. Therefore, when the temperature changes, the warp of the base plate 20 bonded to the TEC 70 including the heat radiating plate 71 via the second bonding material 82 can be suppressed. Therefore, the red laser diode 41, the green laser diode 42, the blue laser diode 43, the first lens 51, the second lens 52, the third lens 53, the first filter 61, the second filter 62, and the second filter mounted on the base plate 20. It is possible to suppress the deviation of the optical axis due to the change in the relative positional relationship of the three filters 63. As a result, the optical axes of the light that is combined in a wide temperature range can be matched with high accuracy.

FIG. 6 is a graph showing the deviation of the optical axis when the coefficient of linear expansion of the support plate 11 is 5.2 × 10 ^{-6 / K.} In FIG. 6, the vertical axis represents the relative angular deviation (deg) in the vertical direction, and the horizontal axis represents the environmental temperature (° C.). The same applies hereinafter to the cases shown in FIGS. 7, 8, 9, and 10. In the case shown in FIG. 6, the material of the heat sink 71 is alumina, and the material of the support plate 11 is Kovar. In this case, assuming that the coefficient of linear expansion of the support plate 11 is C ₁ and the coefficient of linear expansion of the heat radiation plate 71 is C ₂ , the relationship between the coefficient of linear expansion of the support plate 11 and the coefficient of linear expansion of the heat radiation plate 71 is C _1. <it is a _{C 2.} Specifically, C ₁ = 0.675 × C ₂ . FIG. 6 shows the result of dividing each member of the optical module with the cap removed shown in FIG. 2 into small regions by the finite element method and measuring the deviation of the optical axis by CAE (Computer Aided Engineering) analysis. .. The same applies to the cases shown in FIGS. 7 to 10 below. The line indicated by RG indicates the deviation of the optical axis of the light emitted by the red laser diode 41 with respect to the optical axis of the light emitted by the green laser diode 42. The line indicated by BG indicates the deviation of the optical axis of the light emitted by the blue laser diode 43 with respect to the optical axis of the light emitted by the green laser diode 42. The deviation of the optical axis is shown as a deviation of the angle of the optical axis in the vertical direction, that is, in the Z direction. FIG. 7 is a graph showing the deviation of the optical axis when the coefficient of linear expansion of the support plate 11 is 10.0 × 10 ^{-6 / K.} That is, in the case shown in FIG. 7, the relationship between the linear expansion coefficient of the support plate 11 and the linear expansion coefficient of the heat sink 71 is C ₁ > C ₂ . Specifically, C ₁ = 1.3 × C ₂ . Both are adjusted so that the optical axes coincide with each other at 25 ° C.

In CAE, a temperature distribution simulating the operation of the TEC 70 is given to the light forming unit 13, and the deformation of the environmental temperature from −40 ° C. to 85 ° C. is analyzed by the finite element method. The temperature of the light forming unit 13 at this time is 35 ° C. The deviation of the optical axis is evaluated by reflecting the amount of deformation of each element of the light forming unit 13 obtained by the finite element method in the optical analysis.

First, referring to FIG. 7, as the environmental temperature rises or the environmental temperature decreases, the deviation of the optical axis increases as shown by the line indicated by RG and the line indicated by BG. I can understand that. On the other hand, referring to FIG. 6, the optical axis deviates as the environmental temperature rises or the environmental temperature decreases, but the deviation of the optical axis becomes smaller than in the case shown in FIG. ing. Therefore, according to the optical module 10, the optical axes of the light that is combined in a wide temperature range can be matched with high accuracy.

In the present embodiment, the first bonding material 81 is a silver paste in which silver particles are dispersed in a resin binder. Since the silver paste has a relatively low curing temperature, it is possible to reduce the generation of thermal stress during curing. Further, since the silver paste has elasticity to some extent, the warp of the heat radiating plate 71 caused by the difference between the linear expansion coefficient of the support plate 11 and the linear expansion coefficient of the heat radiating plate 71 when the temperature changes is caused by the silver paste itself. It can be tolerated by deformation. Therefore, the reliability of such an optical module 10 can be improved.

(Embodiment 2)
In the above embodiment, the relationship between the linear expansion coefficient of the support plate 11 and the linear expansion coefficient of the heat dissipation plate 71 may be _{C 1} <0.7 × C _2. FIG. 8 is a graph showing the deviation of the optical axis when the coefficient of linear expansion of the support plate 11 is 3.7 × 10 ^{-6 / K.} The coefficient of linear expansion of SiC is, for example, 3.7 × ^10-6 / K. When, for example, SiC is used as the material of the support plate 11, the relationship of _{C 1} <0.7 × C _{2 is satisfied.} Specifically, C ₁ = 0.48 × C ₂ .

With reference to FIG. 8, the optical axis deviates as the environmental temperature rises or the environmental temperature decreases, but the deviation of the optical axis becomes smaller than in the case shown in FIG. Therefore, _{by configuring so as to have a relationship of C 1} <0.7 × C ₂ , it is possible to more reliably match the optical axes of the light to be combined within a wide temperature range with high accuracy. Further, according to the first embodiment and the second embodiment, the material of the support plate 11 is SiC or Kovar, and the material of the heat sink 71 is alumina, so that the optical axis of the light that is combined in a wide temperature range is used. Can be matched with high precision.

(Embodiment 3)
In the above embodiment, the relationship between the linear expansion coefficient of the support plate 11 and the linear expansion coefficient of the heat dissipation plate 71 may be _{C 1} <0.5 × C _2. FIG. 9 is a graph showing the deviation of the optical axis when the coefficient of linear expansion of the support plate 11 is 1.0 × 10 ^{-6 / K.} Here, the coefficient of linear expansion of nickel steel is, for example, 0.9 × ^10-6 / K. When nickel steel is used as the material of the support plate 11, the relationship of _{C 1} <0.5 × C _{2 is satisfied.} Specifically, C ₁ = 0.13 × C ₂ .

With reference to FIG. 9, the optical axis deviates as the environmental temperature rises or the environmental temperature decreases, but the deviation of the optical axis becomes extremely small as compared with the case shown in FIG. Therefore, _{by configuring so as to have a relationship of C 1} <0.5 × C ₂ , it is possible to more reliably match the optical axes of the light to be combined within a wide temperature range with high accuracy.

(Embodiment 4)
In the above embodiment, the relationship between the linear expansion coefficient of the support plate 11 and the linear expansion coefficient of the heat sink 71 may be _{0.1 × C 2} <C ₁ <0.5 × C _2. FIG. 10 is a graph showing the deviation of the optical axis when the coefficient of linear expansion of the support plate 11 is 0.1 × 10 ^{-6 / K.} Here, the coefficient of linear expansion of quartz glass is, for example, 0.5 × ^10-6 / K. When quartz glass is used as the material of the support plate 11, the relationship of _{0.1 × C 2} <C ₁ <0.5 × C _{2 is satisfied.} Specifically, C ₁ = 0.013 × C ₂ .

With reference to FIG. 10, as the environmental temperature rises or the environmental temperature decreases, the optical axis deviates, but the deviation of the optical axis becomes smaller than in the case shown in FIG. In this case, as shown by the line indicated by RG and the line indicated by BG, the tendency of the deviation of the optical axis is reversed as compared with the case shown in FIGS. 8 and 9. If the coefficient of linear expansion of the support plate 11 is 10% or less of the coefficient of linear expansion of the heat radiating plate 71, warpage will occur in the opposite direction. In this way, _{by configuring so as to have the relationship of 0.1 × C 2} <C ₁ <0.5 × C ₂ , the optical axis of the light to be combined within a wide temperature range is more reliably raised. It can be matched to the accuracy.

(Other embodiments)
In the above embodiment, the optical module 10 includes a red laser diode 41, a green laser diode 42, and a blue laser diode 43, but the present invention is not limited to this, and any two colors, that is, a red laser The configuration may include at least two of the diode 41, the green laser diode 42, and the blue laser diode 43.

It should be understood that the embodiments disclosed here are exemplary in all respects and are not restrictive in any way. The scope of the present invention is defined by the scope of claims, not the above description, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

The optical modules of the present disclosure can be applied particularly advantageously when a highly accurate alignment of the optical axes of the combined light over a wide temperature range is required.

10 Optical module 11 Support plate 12A, 12B, 21A, 21B Surface 13 Optical forming part 14 Cap 15 Exit window 16 Lead pin 17 Thermista 20 Base plate 22 Chip mounting area 23 Base area 31 1st submount 32 2nd submount 33 3rd Submount 41 Red laser diode 42 Green laser diode 43 Blue laser diode 51 First lens 52 Second lens 53 Third lens 61 First filter 62 Second filter 63 Third filter 70 TEC
71 Heat sink 72 Heat sink 73 Semiconductor column 81 First joint material 82 Second joint material

Claims (6)

Support plate and
With the first joining material arranged on the support plate,
An electronic cooling module arranged on the first joining material and joined to the support plate by the first joining material.
With the second bonding material arranged on the electronic cooling module,
A light forming portion configured to form light, arranged on the second bonding material, and bonded to the electronic cooling module by the second bonding material is provided.
The light forming part is
A first semiconductor light emitting device that emits light of a first wavelength,
A second semiconductor light emitting device that emits light having a second wavelength different from the first wavelength,
A filter that combines the light of the first wavelength emitted from the first semiconductor light emitting device and the light of the second wavelength emitted from the second semiconductor light emitting device.
The first semiconductor light emitting device, the second semiconductor light emitting element, and a base portion on which the filter is mounted, which are arranged in contact with the second bonding material, are included.
The electronic cooling module
A heat sink arranged in contact with the first joining material and
An endothermic plate arranged in contact with the second bonding material,
A plurality of semiconductor columns connecting the heat radiating plate and the endothermic plate are included.
The coefficient of linear expansion of the heat sink is 4.0 × ^10-6 / K or more and 8.0 × ^10-6 / K or less.
Assuming that the coefficient of linear expansion of the support plate is C ₁ and the coefficient of linear expansion of the heat sink is C ₂ .
The relationship between the coefficient of linear expansion of the support plate and the coefficient of linear expansion of the heat sink is C ₁ <C ₂ , an optical module. The optical module according to claim 1, wherein the relationship between the linear expansion coefficient of the support plate and the linear expansion coefficient of the heat dissipation plate is C ₁ <0.7 × C _2. The optical module according to claim 1 or ₂ , wherein the relationship between the linear expansion coefficient of the support plate and the linear expansion coefficient of the heat dissipation plate is C ₁ <0.5 × C 2. The relationship between the linear expansion coefficient of the support plate and the linear expansion coefficient of the heat dissipation plate is 0.1 × C ₂ <C ₁ <0.5 × C ₂ , any one of claims 1 to 3. The optical module described in the section. The optical module according to any one of claims 1 to 4, wherein the first bonding material is a silver paste in which silver particles are dispersed in a resin binder. The material of the support plate is SiC or Kovar.
The optical module according to any one of claims 1 to 5, wherein the material of the heat sink is alumina.

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