JP2005166735A - Laser light source device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the leakage of scattered light of laser light to the outside while reducing the ambient temperature of a laser diode. <P>SOLUTION: The laser diode 101 is installed on a metal substrate 101 via a Peltier element 110 and a heatsink 102. The laser diode 101, an optical coupling section 103 for making the laser light 104 generated by the laser diode 101 incident into an optical fiber 108, and a predetermined portion from the incident end of the optical fiber 108, are covered by a shading cover 202. Vent holes 207 and 209 are formed in the shading cover 202, and they are covered by unwoven fabric 208 and 210. On the opposite side from the substrate 101, a heat radiation fin 211 and a fan are installed, and the heat radiation fin 211 is forcibly air-cooled. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a laser light source apparatus configured to use a laser diode as a light emitting element and to emit emitted laser light to a means using the laser light through an optical fiber. In particular, the laser diode is connected to the optical fiber. The present invention relates to a laser light source device that includes a coupling portion and is covered with a light shielding cover so that laser light does not leak to the outside, and a laser diode is cooled by cooling means.

  Consumer equipment that uses laser light as a light source has been on the market for a long time, but reducing the cost of such consumer equipment is one of the important themes when designing equipment as a product. It has become. Therefore, an attempt has been made to use a laser diode that can be obtained at a relatively low cost as a light emitting body that generates laser light. For example, Patent Document 1 discloses an example of a projection-type image display device that uses a laser diode as a light source. Yes.

  In this way, when laser diodes are actually incorporated into products such as video display devices, the operating temperature and operating life of laser diodes are greatly affected by the operating temperature. Therefore, the operating temperature is controlled by a cooling element such as a Peltier element. Is done. A laser diode cooling structure using a Peltier element is disclosed in, for example, Patent Document 2.

  In addition, when the laser light generated by the laser diode is used as a light source for projection-type image display or the like, the laser light is usually transmitted to an optical system for using the laser light by an optical fiber. Is done.

  In order to transmit the laser beam generated by the laser diode to the optical fiber, the laser diode and the optical fiber are coupled by an optical coupling means, and thereby the laser beam is emitted to the incident end of the optical fiber.

  At this time, due to structural factors between the optical coupling means, the laser diode, and the optical fiber, the entire laser light is not transmitted to the optical fiber, but a part thereof is scattered around. For this reason, it is considered that the required safety is secured by optically shielding the coupling portion between the laser diode and the optical fiber to prevent the laser light from being emitted to the outside.

  The optical shielding means can be configured to have a structure in which the laser diode, the optical coupling means, and a part of the incident end side of the optical fiber are sealed with a box-shaped light shielding cover.

  However, in an environment where the laser diode is sealed by the light shielding cover, there is no air flow in the light shielding cover, so a part of the heat exhausted from the cooling element is accumulated in the light shielding cover and around the laser diode. There was a problem that the air temperature was raised and it returned to the laser diode to reduce the heat dissipation performance.

  The shading cover is made of a material with low thermal conductivity, such as resin, and air also has a high thermal resistance. Therefore, almost no heat dissipation effect can be expected from the shading cover itself, and the inside of the shading cover becomes hot. This adversely affects the operation and life of the laser diode.

  In this way, if the laser diode is coupled to the optical fiber so that the laser beam is not leaked to the outside, the temperature control of the laser diode will not function well, and the operation of the laser diode may become unstable. Have the problem of shortening the life.

Such a problem is a factor that causes a fatal failure as a device, but no proposal has been made to solve the problem in the past. Not even described.
JP 2002-214706 A (page 23, FIG. 2) JP-A-5-308165 (second page, FIGS. 1 and 2)

  In a light source device configured to transmit laser light generated by a laser diode to an optical system or the like for using the laser light by an optical fiber, the laser diode including a coupling portion with the optical fiber is included. The cover needs to be covered and shielded from light, which raises the problem that the temperature inside the cover rises and adversely affects the laser diode.

  The present invention has been made in response to the above-mentioned points. The laser diode is shielded by providing a ventilation hole closed with a non-woven fiber in a cover that shields the laser diode including the coupling portion with the optical fiber. Laser that leaks to the outside from the cover is greatly reduced, ensuring safety while allowing air to flow inside the cover, enabling laser diode temperature control to be performed satisfactorily. An object of the present invention is to provide a light source device.

  In order to achieve the above object, a laser light source device according to an embodiment of the present invention is attached to a metal base, and a laser diode that generates laser light, and light that derives the laser light generated by the laser diode. A fiber, optical coupling means for transmitting laser light generated by the laser diode to the optical fiber, the laser diode, a light shielding cover for covering the light coupling end of the optical coupling means and the optical fiber, and the light shielding cover And a non-woven fiber provided so as to cover the ventilation light.

  According to the present invention, since the ventilation holes are provided in the light shielding cover and covered with the non-woven fiber, most of the scattered light of the laser is reflected by the mesh of the non-woven fiber. Can be greatly reduced. Further, since the light leaking outside the light shielding cover is diffused when passing through the non-woven fiber, the laser light is not condensed outside the light shielding cover, and safety can be ensured. When the scattered light of the laser is concentrated at one point, the energy density becomes high and the risk becomes high. However, according to the present invention, such a situation can be surely prevented.

  Moreover, regarding heat dissipation, since the ventilation property is ensured by the non-woven fiber, the heat radiated in the light shielding cover can be discharged from the ventilation hole by natural convection. Most of the heat generated in the laser diode is transferred from the cooling element to the heat sink and radiated to the atmosphere by forced air cooling. Since the ratio of the heat exhausted from the cooling element to the inside of the light shielding cover is small, the air temperature in the light shielding cover can be sufficiently lowered even by heat radiation by natural convection.

  As described above, by providing a ventilation hole in the light shielding cover and covering with a non-woven fiber, it is possible to realize a laser light source device having high heat dissipation without impairing the light shielding property.

Hereinafter, an embodiment of a laser light source device of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram schematically showing the configuration of the laser light source device of the present invention in order to explain the main part more easily. In FIG. 1, a laser diode 101 in which a semiconductor laser chip is mounted on a copper submount is fixed by screws on a heat sink 102 made of copper.

  The heat sink 102 is further provided with an optical coupling portion 103 corresponding to the laser light emission direction of the laser diode 101. The optical coupling unit 103 receives the laser light 104 emitted from the laser diode 101 and converts it into parallel light, a condensing lens 106 that condenses the laser light derived from the collimator lens 105, and The collimator lens 105 and the condenser lens 106 are configured by a lens holder 107 that holds the heat sink 102 so as to have a predetermined positional relationship with the laser diode 101.

  Further, an optical fiber 108 is provided to receive the laser beam condensed by the condenser lens 106 of the optical coupling unit 103. The optical fiber 108 is supported on a substrate 201 described later by an optical fiber holder 109, and the laser light 104 from the condenser lens 106 is incident on the incident end thereof.

  Further, the heat absorption side portion of the Peltier element 110 is fixed to the heat sink 102, and the laser diode 101 is cooled by the Peltier element 110 via the heat sink 102. A heat radiation side portion of the Peltier element 110 is fixed to the substrate 201.

  All of the laser light 104 emitted from the laser diode 101 is not transmitted to the optical fiber 108. First, when entering the collimator lens 105, a part of the laser light 104 is reflected to become scattered light 111. Scattered. Further, in the process of entering the optical fiber 108 from the condenser lens 106, the light is reflected at the incident end of the optical fiber 108 and scattered as scattered light 112.

  As described above, since the scattered light 111 and 112 are emitted in the process of transmitting the laser light to the optical fiber 108, it is necessary to cover a portion where the scattered light may be generated with the light shielding cover.

  FIG. 2 is a partial cross-sectional view of the laser light source device of the present invention in which a part of the incident end side of the laser diode 101, the optical coupling unit 103, and the optical fiber 108 shown in FIG.

  2, the same components as those in FIG. 1 are denoted by the same reference numerals. In the laser light source device 200, a heat sink 102 on which a laser diode 101 and an optical coupling unit 103 shown in FIG. 1 are mounted is mounted on a base substrate 201 made of an aluminum alloy via a Peltier element 110.

  Further, an optical fiber holder 109 is attached to the substrate 201. The optical fiber holder 109 has a function of holding the optical fiber 108 with respect to the substrate 201 so that the incident end of the optical fiber 108 is in a predetermined positional relationship with the condenser lens 107 of the optical coupling unit 103. As a result, the spot diameter of the laser light 104 collected by the condenser lens 106 is substantially equal to the diameter of the core portion of the optical fiber 108.

  Further, a light shielding cover 202 is attached to the substrate 201 so as to cover the laser diode 101, the heat sink 102, and the optical fiber holder 109. The light shielding cover 202 has a substantially rectangular parallelepiped appearance, and includes a wall 203 disposed so as to intersect with a direction in which the laser light 104 is emitted from the laser diode 101, and a wall 204 facing the wall 203. The walls 203 and 204 are adjacent to each other and have a top plate 205.

  The wall 203 is provided with a lead-out portion 206 from which the optical fiber 108 is drawn out, and further, a ventilation hole 207 is provided at a position near the top plate 205 of the light shielding cover 202, and the non-woven fiber is formed so as to close the ventilation hole 207. 208 is attached to the wall 203.

  Further, the wall 204 is also provided with a ventilation hole 209 at a position close to the substrate 201, and the non-woven fiber 210 is attached to the wall 204 so as to close the ventilation hole 209.

  A radiation fin member 211 made of aluminum alloy is fixed on the opposite side of the surface of the substrate 201 on which the laser diode 101, the heat sink 102, the Peltier element 110, etc. are mounted, and further, air is sent to the radiation fin 211 to cool it. The fan 212 is provided.

  The non-woven fibers 208 and 210 are made by laminating stainless metal fibers having a diameter of about 10 μm (micrometer) to 80 μm in a felt shape having a thickness of about 0.5 mm (millimeter) to 1.0 mm. Has porosity.

  Since the material is a metal fiber, it has high heat resistance and is not damaged by heating even when it is exposed to laser scattered light. Further, since it has a high porosity, it does not hinder the movement of air inside and outside the light shielding cover 202.

  For example, when a non-woven fiber having a porosity of 80% and a thickness of 0.5 mm made of stainless fiber having a diameter of 12 μm is used, the pressure loss at a wind speed of 0.05 m / s (second speed in meters) is 5 Pa ( From Pascal) to 10 Pa, it was confirmed that a sufficient amount of ventilation could be obtained. Further, the transmittance was found to be less than the natural light level when the light intensity after irradiating the inside of the light shielding cover 202 with laser light having a wavelength of 633 nm (nanometer) and passing through the non-woven fibers 207 and 209 was measured.

  In the laser light source device 200 configured as described above, natural convection of air is generated in the light shielding cover inside 201 by heat released from the Peltier element 110 into the light shielding cover 202. By this natural convection, the heated air in the light shielding cover 210 rises from the vicinity of the substrate 201 toward the top plate 205. Along with this, outside air flows from the ventilation holes 209 provided in the wall 204 of the light shielding cover 202 via the non-woven fibers 210, and externally from the ventilation holes 210 provided in the walls 203 via the non-woven fibers 208. Will be discharged.

  FIG. 3 is a view of the laser light source device 200 shown in FIG. 2 as viewed from the direction of the top plate 205 of the light shielding cover 202. 3, the same components as those in FIG. 2 are denoted by the same reference numerals, and detailed description thereof is omitted.

  Ventilation holes 207 and 209 are provided at substantially the center in the width direction of the walls 203 and 204 of the light shielding cover 202.

  According to the laser light source device 200 configured as described above, the laser light leaking outside from the light shielding cover 202 can be greatly reduced by the function of the non-woven fibers 208 and 210.

  In addition, most of the heat generated in the light shielding cover 202 is radiated into the atmosphere from the Peltier element 110 via the substrate 201 and the radiation fins 211, so that the ratio of the heat released into the light shielding cover 202 is small and natural convection. The air temperature in the light-shielding cover 202 can be kept sufficiently low even with heat radiation by the above.

  In the embodiment described above, the heat in the light shielding cover 202 is dissipated by natural convection of the air in the light shielding cover 202. However, since the fan 212 is provided, the light is shielded by utilizing this. It can also be configured such that outside air is forcibly sent into the cover 202 to dissipate the internal heat.

  FIG. 4 is a diagram showing an embodiment in which the inside of the light shielding cover 202 is forcibly air-cooled using the fan 212. The same components as those in FIG. To do.

  That is, in the laser light source device 400 shown in FIG. 4, an opening 401 is provided between the fan 212 attachment position and the fin attachment position of the substrate 201, and the nonwoven fiber 402 is attached so as to cover the opening 401. ing.

  According to the laser light source device 400 shown in FIG. 4, the air sent to the heat radiating fins 211 by the fan 212 strikes the walls of the heat radiating fins, flows in the direction of the substrate 201, and is blocked by the openings 401 and the non-woven fibers 402. It flows into the cover 202.

  The air flowing into the light shielding cover 202 is exhausted from the ventilation holes 207 and 209 through the non-woven fibers 208 and 210. As a result, it is possible to reliably suppress an increase in the temperature in the light shielding cover.

  As described above, according to the laser light source device of the present invention, since the light shielding cover that shields the scattered light of the laser light is provided with the ventilation hole covered with the non-woven fiber, the temperature inside the light shielding cover is surely ensured. It is possible to provide a laser light source device capable of ensuring sufficient safety because the operation of the laser diode can be made stable by reducing the amount of the scattered light to a low level, and the leakage of scattered light can be greatly reduced. It can be done.

  The present invention is not limited to the embodiment described above, and can be implemented in various ways without changing the gist thereof.

The block diagram which shows typically the principal part of the laser light source apparatus of this invention. The figure which shows the state which looked at one Embodiment of the laser light source device of this invention from the side in a partial cross section. The figure which shows the state which looked at the laser light source apparatus shown in FIG. 2 from the upper surface direction in a partial cross section. The figure which shows other embodiment of the laser light source apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100,400 ... Laser light source apparatus 101 ... Laser diode 102 ... Heat sink 103 ... Optical coupling part 104 ... Laser beam 105 ... Collimator lens 106 ... Condensing lens 108,113,124 ... Condensing lens 107 ... Lens folder 108 ... Optical fiber 109 ... Optical fiber holder 110 ... Peltier element 201 ... Substrate 202 ... Light shielding cover 203, 204 ... Wall 205 ... Top plate 207, 209 ... Ventilation holes 208, 210, 402 ... Non-woven fiber 211 ... Radiation fins 212 ... Fan 401 ... Opening

Claims (6)

A laser diode attached to a metal base and generating laser light;
An optical fiber for deriving laser light generated by the laser diode;
Optical coupling means for transmitting laser light generated by the laser diode to the optical fiber;
A light shielding cover for covering the laser diode, the optical means and the light incident end of the optical fiber;
A ventilation hole provided in the light shielding cover;
Non-woven fibers provided to cover this ventilation light,
A laser light source device comprising: 2. The laser light source device according to claim 1, wherein the non-woven fiber is a metal having a diameter of approximately 80 μm or less and has a porosity of approximately 60% to 90%. The vent hole is configured by a plurality, and is provided at a position for sucking outside air and a position for discharging internal air in accordance with natural convection of air in the light shielding cover. 2. The laser light source device according to 1. The laser light source device according to claim 1, wherein a Peltier element having a heat radiation member provided on the heat radiation site side is attached to the base. The laser light source device according to claim 4, wherein a fan for forcibly air-cooling the heat radiating member is provided. 2. The laser light source device according to claim 1, wherein air is forcibly fed into the light shielding cover, and the fed air is exhausted from the ventilation hole through the nonwoven fiber.

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