JP2012248558A - Laser light source device - Google Patents

Abstract

An object of the present invention is to provide a laser light source device capable of preventing a reduction in conversion efficiency of a wavelength conversion element and reducing the size and cost of the laser light source device by adopting a direct bonding configuration.
A solid laser element, a wavelength conversion element, and a convex part are directly joined to form a directly joined SHG element, and an optical axis of an infrared laser beam having a fundamental wavelength is directly connected to the directly joined SHG element. Is provided with an inclined surface 100 that has a predetermined amount of inclination and reflects converted light obtained by wavelength-converting infrared laser light.
[Selection] Figure 4

Description

  The present invention relates to a laser light source device using a semiconductor laser, and more particularly to a laser light source device used for a light source of an image display device.

  In recent years, a technique using a semiconductor laser as a light source of an image display device has attracted attention. This semiconductor laser has better color reproducibility, instantaneous lighting, longer life, and higher efficiency and lower power consumption compared to mercury lamps that have been widely used in image display devices. It has various advantages, such as being able to be made and being easy to miniaturize.

  In the laser light source device used for such an image display device, since there is no high-power semiconductor laser that directly outputs green laser light, the pumping laser light is output from the semiconductor laser, and this pumping laser light is used. A technique is known in which a solid-state laser element is excited to output infrared laser light, and the wavelength of the infrared laser light is converted by a wavelength conversion element to output green laser light (for example, Patent Document 1). reference).

  In recent years, in order to reduce the number of parts of the laser light source device and to reduce the size and cost of the laser light source device, a structure in which the solid-state laser element used in the laser light source device and the wavelength conversion element are directly bonded is used. Has been proposed.

JP 2008-16833 A

  However, in the directly bonded solid-state laser element and wavelength conversion element, each end face on the optical axis is formed perpendicular to the optical axis in order to form a resonance path of infrared laser light, that is, the solid-state laser element Since the end faces of the wavelength conversion element are parallel to each other, interference with the green laser light produced by the conversion of the infrared laser light by the wavelength conversion element on the resonance path of the infrared laser light output from the solid-state laser element occurs. This causes a problem that the conversion efficiency of the wavelength conversion element is lowered.

  The present invention has been devised to solve such problems of the prior art, and prevents a decrease in the conversion efficiency of the wavelength conversion element, and the laser light source device can be downsized by adopting a direct bonding configuration. An object of the present invention is to provide a laser light source device capable of reducing the cost.

  In order to solve the above problems, a laser light source device of the present invention includes a semiconductor laser that outputs excitation laser light, and a solid-state laser element that outputs infrared laser light having a fundamental wavelength by the excitation laser light output from the semiconductor laser. And a direct bonding element obtained by directly bonding a wavelength conversion element that converts the wavelength of laser light output from the solid-state laser to ½, and the bonding surface of the direct bonding element is on the optical axis of the infrared laser light The inclined surface reflects the converted light obtained by converting the wavelength of the infrared laser beam reflected from the output surface of the wavelength conversion element, and the optical axis and basic of the reflected converted light. A predetermined amount of inclination is provided between the optical axis of the infrared laser light having the wavelength.

  According to the present invention, it is possible to prevent a decrease in the conversion efficiency of the wavelength conversion element by providing a cross section with a simple configuration in the directly bonded solid-state laser element and the wavelength conversion element. Further, the adoption of the direct bonding configuration can reduce the size and cost of the laser light source device, and the number of components reduces the assembly and adjustment of the laser light source device.

1 is a schematic configuration diagram of an image display device according to a first embodiment of the present invention. The perspective view of the green laser light source device in the 1st Embodiment of this invention Schematic which shows the optical path of the laser beam of the green laser light source apparatus in the 1st Embodiment of this invention Schematic diagram showing the state of the laser beam of the green laser light source device in the first embodiment of the present invention The form figure which shows the form of the direct junction part in the 2nd Embodiment of this invention The form figure which shows the form of the direct junction part in the 3rd Embodiment of this invention

  The invention according to claim 1 is output from the semiconductor laser that outputs the excitation laser beam, the solid-state laser element that outputs the infrared laser beam having the fundamental wavelength by the excitation laser beam output from the semiconductor laser, and the solid-state laser. A direct bonding element obtained by directly bonding a wavelength conversion element that converts the wavelength of the laser light to ½, and the bonding surface of the direct bonding element is an inclined surface that is inclined with respect to the optical axis of the infrared laser light The inclined surface reflects the converted light obtained by converting the wavelength of the infrared laser light reflected from the output surface of the wavelength conversion element, and reflects the optical axis of the reflected converted light and the infrared laser light having the fundamental wavelength. A laser light source device having a predetermined amount of inclination with respect to the optical axis of the laser beam, wherein a cross-section having a simple configuration is provided in an integrated element in which a solid-state laser element and a wavelength conversion element are directly joined Of the wavelength conversion element It is possible to prevent a decrease in 換効 rate. Further, the adoption of the direct bonding configuration can reduce the size and cost of the laser light source device, and the number of components reduces the assembly and adjustment of the laser light source device.

  The invention according to claim 2 is the laser light source device according to claim 1, wherein the predetermined amount of inclination is 1 degree or more and 5 degrees or less. The output direction of the reflected half-wavelength laser light is reduced from the original optical axis direction to prevent the output characteristics of the green laser light source device from deteriorating, and the fundamental wavelength laser light and the half-wavelength laser light reflected by the inclined surface Interference can be reduced, and a decrease in conversion efficiency of the wavelength conversion element can be prevented.

  The invention according to claim 3 is the laser light source device according to claim 1, wherein the output surface of the wavelength conversion element is convex, and the laser light in the optical axis direction of the fundamental wavelength laser light is Even if it is displaced from the optical axis direction due to refraction at the inclined surface, it is restored to the original optical axis by the curvature shape of the convex portion, and the excitation of the fundamental wavelength laser can be maintained stably.

  According to a fourth aspect of the present invention, the semiconductor laser, the solid-state laser element, and the direct junction element are integrally supported by one base. The laser light source device described above can easily adjust the optical axis by using this configuration, and can output high-power laser light, and the optical system of the laser light source device can be simplified by incorporating a slab shape. And the number of components of the optical system can be reduced, and the laser light source device can be reduced in size and cost.

  The laser light source device of the present invention will be described below with reference to the drawings. In addition, although the Example described below is a suitable specific example of this invention and limitation of technically favorable conditions is described, the scope of the present invention limits this invention especially in the following description. As long as there is no description, it is not restricted to these conditions.

(First embodiment)
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a first embodiment of the invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of an image display apparatus according to the first embodiment of the present invention. The image display device 1 projects and displays a required image on a screen, and outputs a green laser light source device 2 that outputs green laser light, a red laser light source device 3 that outputs red laser light, and a blue laser light. The blue laser light source device 4 to output, the liquid crystal reflection type spatial light modulator 5 that modulates the laser light from each laser light source device 2 to 4 according to the video signal, and the laser from each laser light source device 2 to 4 A polarization beam splitter 6 that reflects light to irradiate the spatial light modulator 5 and transmits the modulated laser light emitted from the spatial light modulator 5, and polarizes the laser light emitted from each of the laser light source devices 2 to 4. A relay optical system 7 that leads to the beam splitter 6 and a projection optical system 8 that projects the modulated laser light transmitted through the polarization beam splitter 6 onto a screen are provided.

  The image display device 1 displays a color image by a so-called field sequential method. Laser beams of each color are sequentially output from the laser light source devices 2 to 4 in a time-sharing manner, and an image by the laser beam of each color is visually displayed. It is recognized as a color image by the afterimage effect.

  The relay optical system 7 includes collimator lenses 11 to 13 that convert the laser beams of the respective colors emitted from the laser light source devices 2 to 4 into parallel beams, and the laser beams of the respective colors that have passed through the collimator lenses 11 to 13 in a predetermined direction. First and second dichroic mirrors 14 and 15, a diffusion plate 16 for diffusing the laser light guided by the dichroic mirrors 14 and 15, and a field lens for converting the laser light that has passed through the diffusion plate 16 into a convergent laser 17.

  Assuming that the side from which the laser light is emitted from the projection optical system 8 toward the screen S is the front side, the blue laser light is emitted backward from the blue laser light source device 4 and is green with respect to the optical axis of the blue laser light. The green laser beam and the red laser beam are emitted from the green laser light source device 2 and the red laser light source device 3 so that the optical axis of the laser beam and the optical axis of the red laser beam are orthogonal to each other. , And green laser light are guided to the same optical path by the two dichroic mirrors 14 and 15. That is, the blue laser light and the green laser light are guided to the same optical path by the first dichroic mirror 14, and the blue laser light, the green laser light, and the red laser light are guided to the same optical path by the second dichroic mirror 15.

  The first and second dichroic mirrors 14 and 15 are formed with a film for transmitting and reflecting laser light having a predetermined wavelength on the surface, and the first dichroic mirror 14 transmits blue laser light. And reflects the green laser light. The second dichroic mirror 15 transmits red laser light and reflects blue laser light and green laser light.

  Each of these optical members is supported by the casing 21. The housing 21 functions as a radiator that dissipates heat generated by the laser light source devices 2 to 4 and is formed of a material having high thermal conductivity such as aluminum or copper.

  The green laser light source device 2 is attached to an attachment portion 22 formed in the housing 21 in a state of protruding toward the side. The mounting portion 22 is provided in a state of projecting in a direction perpendicular to the side wall portion 24 from a corner portion where the front wall portion 23 and the side wall portion 24 located respectively in front and side of the accommodation space of the relay optical system 7 intersect. ing. The red laser light source device 3 is attached to the outer surface side of the side wall portion 24 while being held by the holder 25. The blue laser light source device 4 is attached to the outer surface side of the front wall portion 23 while being held by the holder 26.

  The red laser light source device 3 and the blue laser light source device 4 are configured by a so-called CAN package, and the optical axis is positioned on the central axis of the can-shaped exterior portion with the laser chip that outputs the laser light supported by the stem. The laser beam is emitted from a glass window provided in the opening of the exterior part. The red laser light source device 3 and the blue laser light source device 4 are fixed to the holders 25 and 26 by, for example, press-fitting into mounting holes 27 and 28 provided in the holders 25 and 26. The heat generated by the laser chips of the blue laser light source device 4 and the red laser light source device 3 is transmitted to the housing 21 through the holders 25 and 26 to be dissipated, and each of the holders 25 and 26 has a thermal conductivity such as aluminum or copper. It is made of a high material.

  The green laser light source device 2 includes a semiconductor laser 31 that outputs excitation laser light, and a condensing lens that condenses the excitation laser light output from the semiconductor laser 31, a FAC (Fast-Axis Collimator) lens 32 and a rod lens 33. A solid-state laser element 34 that is excited by the excitation laser beam and outputs a basic laser beam (infrared laser beam), and a so-called SHG that converts the wavelength of the basic laser beam and outputs a half-wavelength laser beam (green laser beam). (Second Harmonics Generation) Directly-bonded SHG element 110 (which will be described in detail later) in which wavelength conversion element 35 and convex part 80 are integrally directly bonded, and prevents leakage of excitation laser light and fundamental wavelength laser light. A glass cover 37 for supporting, a base 38 for supporting each part, and covering each part And a cover body 39.

  The green laser light source device 2 is fixed by attaching a base 38 to the mounting portion 22 of the housing 21, and a required width (for example, 0.5 mm) between the green laser light source device 2 and the side wall portion 24 of the housing 21. The following gaps are formed. This makes it difficult for the heat of the green laser light source device 2 to be transmitted to the red laser light source device 3, suppresses the temperature rise of the red laser light source device 3, and allows the red laser light source device 3 with poor temperature characteristics to operate stably. Can do. Further, in order to secure a required optical axis adjustment allowance (for example, about 0.3 mm) of the red laser light source device 3, a required width (for example, 0.3 mm or more) is provided between the green laser light source device 2 and the red laser light source device 3. ) Is provided.

  FIG. 2 is a perspective view of the green laser light source device according to the first embodiment of the present invention.

  As shown in FIG. 2, the semiconductor laser 31, the FAC lens 32, the rod lens 33, and the directly bonded SHG element 110 are integrally supported by the base 38. The bottom surface 51 of the base 38 is parallel to the optical axis direction. Here, the direction orthogonal to the bottom surface 51 of the base 38 is defined as the height direction, and the direction orthogonal to the height direction and the optical axis direction is defined as the width direction. In addition, the side close to the bottom surface 51 of the base 38 will be described below, and the side opposite to the bottom surface 51 will be described above, but this does not necessarily coincide with the vertical direction of the actual apparatus.

  The semiconductor laser 31 is obtained by mounting a laser chip 41 that outputs laser light on a mount member 52. The laser chip 41 has a long strip shape in the optical axis direction, and is fixed to a substantially central position in the width direction of one surface of the plate-shaped mount member 52 with the light output surface facing the FAC lens 32 side. Yes. The semiconductor laser 31 is fixed to the base 38 via an attachment member 53. The mounting member 53 is formed of a metal having high thermal conductivity such as copper or aluminum, and thereby heat generated by the laser chip 41 is transmitted to the base 38 and can be dissipated.

  The FAC lens 32 and the rod lens 33 are held by a condenser lens holder 54. The condenser lens holder 54 is supported by a support portion 55 formed integrally with the base 38. The condensing lens holder 54 is coupled to the support portion 55 so as to be movable in the optical axis direction, whereby the positions of the condensing lens holder 54, that is, the FAC lens 32 and the rod lens 33 are adjusted in the optical axis direction. . The FAC lens 32 and the rod lens 33 are fixed to the condenser lens holder 54 with an adhesive before the position adjustment work, and after the position adjustment work, the condenser lens holder 54 and the support portion 55 are fixed to each other with an adhesive. .

  The directly bonded SHG element 110 including the solid-state laser element 34, the wavelength converting element 35, and the convex portion 80 (see FIG. 1) is held by the directly bonded SHG element holder 58. The directly bonded SHG element holder 58 is movable in the width direction with respect to the base 38 so that the position of the directly bonded SHG element 110 in the width direction and the inclination angle with respect to the optical axis direction can be adjusted. It is provided so as to be rotatable around an axis substantially orthogonal to the optical axis direction. The direct bonding SHG element 110 is fixed to the direct bonding SHG holder 58 with an adhesive before the position adjustment operation, and after the position adjustment operation, the direct bonding SHG element holder 58 and the base 38 are fixed to each other with an adhesive. Thereby, the optical axis of the laser beam output from the semiconductor laser 31 and the optical axis of the FAC lens 32, the rod lens 33, and the directly bonded SHG element 110 can be easily adjusted, and a high-output green laser beam can be output. it can.

  Next, the behavior of the laser beam of the green laser light source device 2 will be described in detail with reference to FIGS.

  FIG. 3 is a schematic view showing the optical path of the laser light of the green laser light source device in the first embodiment of the present invention, and FIG. 4 is the situation of the laser light of the green laser light source device in the first embodiment of the present invention. FIG.

  As shown in FIG. 3, the laser chip 41 of the semiconductor laser 31 outputs an excitation laser beam having a wavelength of 808 nm (one-dot chain line in FIG. 3). The FAC lens 32 reduces the longitudinal spread of the excitation laser light having a wavelength of 808 nm, and the rod lens 33 reduces the lateral spread of the excitation laser light having a wavelength of 808 nm.

  The solid-state laser element 34 is a polycrystal produced by using a so-called ceramic manufacturing method, and is excited by a pumping laser beam having a wavelength of 808 nm that has passed through the rod lens 33 to be a fundamental wavelength laser beam having a wavelength of 1064 nm (the broken line in FIG. 3). ) Is output. This solid-state laser element 34 uses yttrium aluminum garnet having a high linear light transmittance. This yttrium aluminum garnet has a cubic crystal structure, so there is no birefringence and no light scattering at the crystal interface. Used as a thing. The ceramic element of the solid state laser element 34 is known as an inexpensive element.

  On the surface of the solid-state laser element 34 facing the rod lens 33, a film 42 having an antireflection function for the excitation laser beam having a wavelength of 808 nm and a high reflection function for the fundamental wavelength laser beam having a wavelength of 1064 nm is formed. Yes.

  The wavelength conversion element 35 has a periodic polarization inversion structure in which polarization inversion regions and non-polarization inversion regions are alternately formed in a ferroelectric crystal, and emits a fundamental wavelength laser beam in the polarization inversion period direction. Make it incident. As a result, it is possible to obtain a laser beam having a double frequency, that is, a half wavelength, by the second harmonic generation of incident light by quasi phase matching. As the ferroelectric crystal, for example, LN (lithium niobate) added with MgO is used.

  The wavelength conversion element 35 converts the fundamental wavelength laser light (infrared laser light) having a wavelength of 1064 nm output from the solid-state laser element 34 to convert the half wavelength laser light (green laser light) having a wavelength of 532 nm, which is ½ of the fundamental wavelength. To output a dotted line in FIG.

  The two elements, the solid-state laser element 34 and the wavelength conversion element 35 described above, are directly bonded by their opposed inclined surfaces 100. The so-called solid-state laser element 34, wavelength conversion element 35, and convex part 80 (the convex part will be described later) are directly joined by optical contact (optical adhesion) that does not use an adhesive or the like, and are directly joined integrally. The SHG element 110 is obtained.

  The inclined surface 100 is a plane having an angle inclined by about 1 to 5 degrees with respect to a surface perpendicular to the optical axis of the laser beam. In this embodiment, the inclined angle is set to approximately 2 degrees. When this angle is set, the output direction of the half-wavelength laser light reflected by the inclined surface 100 is prevented from deviating from the original optical axis direction, and the output characteristics of the green laser light source device 2 are prevented from being deteriorated. Interference with the half-wavelength laser light can be reduced, and a decrease in conversion efficiency in the wavelength conversion element 35 can be prevented.

  3 and 4, the inclined surface 100 is illustrated as rising to the right, but may be increasing to the left. In short, it is important that the surface of the inclined surface 100 is inclined.

  Here, the medium of the solid-state laser element 34 passes a fundamental wavelength laser beam having a wavelength of 1064 nm, and the medium of the wavelength conversion element 35 is passed a fundamental wavelength laser beam having a wavelength of 1064 nm and a half-wavelength laser beam having a wavelength of 532 nm. The larger the difference in refractive index between the medium of the solid-state laser element 34 and the medium of the wavelength conversion element 35, the greater the function of the inclined surface 100 as a high reflection function.

  Further, a convex portion 80 having a convex shape is formed on the surface of the direct bonding SHG element 110 on the laser light output side. A film 46 is formed on the surface of the convex portion 80. The film 46 has a function of high reflection with respect to a fundamental wavelength laser beam having a wavelength of 1064 nm and a function of preventing reflection (transmission) with respect to a half wavelength laser beam having a wavelength of 532 nm. Prepare.

  Since the fundamental wavelength laser beam having a wavelength of 1064 nm is slightly deviated from the optical axis by the curvature effect of the film 46 formed on the convex portion 80, the original optical axis can be restored. A fundamental wavelength laser beam having a wavelength of 1064 nm resonates and is amplified between the inner surface of 80.

  If the convex portion 80 is not a convex surface but a flat surface, if the fundamental wavelength laser beam with a wavelength of 1064 nm is deviated from the optical axis for some reason, it will go further away from the optical axis and it will be difficult to restore the original optical axis. End up.

  The curvature R of the convex portion 80 is obtained from satisfying the resonance mode stability condition of the resonator and forming a necessary beam diameter in the resonator. The type of medium, the wavelength in the resonator, the beam diameter, and the resonator It is calculated from the interval. In the present embodiment, since the medium of the convex portion 80 uses lithium niobate having a refractive index of 2, this curvature R is approximately 40 mm.

  Next, functions of the inclined surface 100 and the convex portion 80 on the optical path of the laser beam of the green laser light source device 2 will be described with reference to FIG.

  In the present embodiment, the refractive index of the wavelength conversion element 35 is larger than the refractive index of the solid-state laser element 34, and the convex portion 80 is made of the same material as that of the wavelength conversion element 35. If the refractive index of the wavelength conversion element 35 and the refractive index of the convex portion 80 are different, an antireflection (transmission) function for a fundamental wavelength laser beam having a wavelength of 1064 nm and a half-wavelength laser beam having a wavelength of 532 nm therebetween. A film having the following may be formed.

  As shown in FIG. 4A, the excitation laser light having a wavelength of 808 nm output from the laser chip 41 of the semiconductor laser 31 passes through the film 42 via the FAC lens 32 and the rod lens 33 and is a ceramic laser. It is incident on the solid laser element 34 (STEP 1).

  When the excitation laser beam is input to the solid-state laser element 34, the excitation laser beam is excited by the excitation laser beam having a wavelength of 808 nm and outputs a fundamental wavelength laser beam having a wavelength of 1064 nm (STEP 2).

  Next, when the fundamental wavelength laser light having a wavelength of 1064 nm output from the solid-state laser element 34 is input to the wavelength conversion element 35 through the inclined surface 100, a part of the fundamental wavelength laser light is converted into a wavelength by the wavelength conversion element 35. The wavelength of the laser beam is converted to 532 nm laser light (green), and the laser beam is output from the green laser light source device 2 through the convex portion 80 and the film 46 (STEP 3).

  The fundamental wavelength laser light having a wavelength of 1064 nm that has not been converted by the wavelength conversion element 35 is reflected by the film 46 and returns to the wavelength conversion element 35 again. At this time, even if the laser beam in the optical axis direction of the fundamental wavelength laser beam having a wavelength of 1064 nm deviates from the optical axis direction due to refraction at the inclined surface 100 or the like, it is restored to the original optical axis by the curvature shape of the convex portion 80, and the basic The excitation of the wavelength laser is kept stable (STEP 4).

  The fundamental wavelength laser beam having a wavelength of 1064 nm reflected by the film 46 and returned to the wavelength conversion element 35 is again wavelength-converted by the wavelength conversion element 35 into a laser beam (green) having a wavelength of 532 nm. The wavelength-converted laser beam with a wavelength of 532 nm is reflected by the difference in refractive index between the solid-state laser element 34 and the wavelength conversion element 35 on the inclined surface 100 formed in the directly bonded SHG element 110. At this time, the laser beam having a wavelength of 532 nm reflected by the inclined surface 100 proceeds in a direction shifted from the original optical axis direction due to the inclination of the inclined surface 100 (see FIG. 4B).

  Further, about several percent of the fundamental wavelength laser beam having a wavelength of 1064 nm that has not been converted by the wavelength conversion element 35 is reflected by the inclined surface 100 and returns to the wavelength conversion element 35 side, and the rest is refracted by the inclined surface 100 to shift the optical axis. (The light beam display in FIG. 4B is extremely described) The process proceeds to the solid-state laser element 34 side (STEP 5).

  As described above, the inclined surface 100 has a refractive index of the wavelength conversion element 35 larger than that of the solid-state laser element 34 with respect to the refractive indexes of the solid-state laser element 34 and the wavelength conversion element 35 on both sides thereof, and emits laser light having a wavelength of 532 nm. Has the function of reflecting film to reflect.

  The fundamental wavelength laser beam having a wavelength of 1064 nm that has traveled toward the solid-state laser element 34 is reflected by the above-described film 42 at the end of the solid-state laser element 34 and returns again toward the solid-state laser element 34 and the wavelength conversion element 35. (STEP 6).

  Here, the laser beam B1 that is input from the solid-state laser element 34 to the wavelength conversion element 35, wavelength-converted by the wavelength conversion element 35, and output from the wavelength conversion element 35, and the wavelength conversion element once reflected by the film 46. In the state where the laser beam B2 input to the laser beam 35 and reflected by the inclined surface 100 and output from the wavelength conversion element 35 overlaps with each other, the half-wavelength laser beam having a wavelength of 532 nm and the fundamental wavelength laser beam having a wavelength of 1064 nm interfere with each other. Cause output to drop.

  Therefore, as shown in FIG. 4B, since the inclined surface 100 is inclined with respect to the optical axis direction as described above, the laser light beams B1 and B2 overlap each other due to the refracting action on the inclined surface 100. In order not to match, interference between the half-wavelength laser beam having a wavelength of 532 nm and the fundamental wavelength laser beam having a wavelength of 1064 nm is prevented, so that a decrease in output can be avoided. On the other hand, even if the fundamental wavelength laser beam having a wavelength of 1064 nm is deviated from the optical axis direction, it is restored to the original optical axis by the curvature shape of the convex portion 80.

  That is, since the conversion from the fundamental wavelength laser beam having a wavelength of 1064 nm to the half wavelength laser beam having a wavelength of 532 nm is performed in an optical path deviating from the optical path through which the half wavelength laser beam having a wavelength of 532 nm passes, interference of these laser beams is prevented. Therefore, it is possible to prevent a decrease in conversion efficiency from a fundamental wavelength laser beam having a wavelength of 1064 nm to a half wavelength laser beam having a wavelength of 532 nm.

  The glass cover 37 shown in FIG. 1 is formed with a film that does not transmit these laser beams in order to prevent the excitation laser beam having a wavelength of 808 nm and the fundamental wavelength laser beam having a wavelength of 1064 nm from leaking to the outside. ing.

  As described above, the direct bonding SHG element 110 in which the solid-state laser element 34 and the wavelength conversion element 35 are integrated is structured such that the boundary surface between the solid-state laser element 34 and the wavelength conversion element 35 is inclined and directly bonded by an optical contact. And having a convex shape at the output side end of the directly bonded SHG element 110, it is possible to prevent interference between a fundamental wavelength laser beam having a wavelength of 1064 nm and a half wavelength laser beam having a wavelength of 532 nm, and a fundamental wavelength laser having a wavelength of 1064 nm. It is possible to prevent a decrease in conversion efficiency from light to half-wavelength laser light having a wavelength of 532 nm.

  Further, since the two structural members of the solid-state laser element 34 and the wavelength conversion element 35 are integrated, the green laser light source device 2 can be reduced in size and cost, and the green laser light source device 2 can be easily assembled. And the adjustment time can be reduced. Furthermore, the assembly accuracy is improved by integrating the constituent members, and the positional accuracy can be reduced.

(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. Here, members having the same configuration and function as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The difference between the present embodiment and the first embodiment is a method of configuring the inclined surface 100 that is directly joined by optical contact. Hereinafter, this different point will be described in detail.

  FIG. 5 is a view showing the form of the direct joining portion in the second embodiment of the present invention.

  In FIG. 5, the solid-state laser element 34 and the wavelength conversion element 35 are made by changing the constituent ratios of the respective materials described above so that the refractive indexes thereof are the same. Therefore, on the inclined surface 100, the fundamental wavelength laser beam having a wavelength of 1064 nm can go straight without being refracted, and laser excitation can be continued stably.

  However, under this condition, a half-wavelength laser beam having a wavelength of 532 nm obtained by converting the fundamental wavelength laser beam having a wavelength of 1064 nm returned from the convex portion 80 by the wavelength conversion element 35 also passes through the inclined surface 100. Therefore, in this embodiment, the inclined surface 100, that is, the slope of the wavelength conversion element 35 or the slope of the solid-state laser element has a function of preventing reflection of the fundamental wavelength laser beam having a wavelength of 1064 nm, and highly reflects half-wavelength laser light having a wavelength of 532 nm. A film 120 having a function is formed. That is, the film 120 is sandwiched between the solid laser element 34 and the wavelength conversion element 35 on the inclined surface 100, and the solid laser element 34 and the wavelength conversion element 35 are directly bonded.

  Note that when the film 120 is formed between the solid-state laser element 34 and the wavelength conversion element 35, optical contact (optical bonding) is not essential. It may be a pseudo direct bonding state in which a gap exists and is fixed with an adhesive or the like.

  The half-wavelength laser light having a wavelength of 532 nm reflected by the film 120 travels in a direction shifted from the original optical axis direction due to the inclination of the film 120 on the inclined surface 100 and is output from the green laser light source device 2.

  The reflected half-wavelength laser light having a wavelength of 532 nm travels in a direction deviated from the original optical axis direction, thereby deviating from the optical path through which the half-wavelength laser light having the wavelength of 532 nm described in the first embodiment passes. Since the conversion from the fundamental wavelength laser beam having a wavelength of 1064 nm to the half wavelength laser beam having a wavelength of 532 nm is performed, interference of these laser beams can be prevented and the half wavelength laser having a wavelength of 532 nm can be prevented from the fundamental wavelength laser beam having a wavelength of 1064 nm A decrease in light conversion efficiency can be prevented.

(Third embodiment)
Hereinafter, a third embodiment of the present invention will be described with reference to the drawings. Here, members having the same configuration and function as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The difference between the present embodiment and the first embodiment is a method of configuring the inclined surface 100 that is directly joined by optical contact. That is, in this embodiment, there are two places to be joined directly. Hereinafter, this different point will be described in detail.

  FIG. 6 is a view showing the form of the direct joint portion in the third embodiment of the present invention.

  In FIG. 6, the wavelength conversion element 35 is divided into two parts to be two constituent elements 35 a and 35 b, and the two constituent elements 35 a and 35 b are formed with an inclined surface 100 therebetween and directly joined by optical contact.

  However, the component 35a functions as a wavelength conversion function, and the component 35b is located at the end of the wavelength conversion element 35 and does not function as a wavelength conversion function.

  In this case as well, as described in the second embodiment (FIG. 5), a film 120 is formed on the inclined surface 100, and the half-wavelength laser light having a wavelength of 532 nm reflected by the film 120 is the original. By proceeding in a direction deviating from the optical axis direction, the half wavelength of the wavelength 532 nm from the fundamental wavelength laser light of the wavelength 1064 nm is deviated from the optical path through which the half wavelength laser light of the wavelength 532 nm described in the first embodiment passes. Since conversion into laser light is performed, interference of these laser lights can be prevented, and reduction in conversion efficiency from basic wavelength laser light with a wavelength of 1064 nm to half-wavelength laser light with a wavelength of 532 nm can be prevented.

  On the other hand, since the fundamental wavelength laser beam having a wavelength of 1064 nm is in the same member on the inclined surface 100, the laser beam can go straight without being refracted and the laser can be stably excited. A part of the fundamental wavelength laser beam is reflected by the inclined surface, but is used again for excitation of the laser beam by the reflection function of the convex portion 80 as described in the first embodiment.

  The component 35b of the wavelength conversion element 35 and the solid-state laser element 34 are opposed to each other in a plane perpendicular to the optical axis of the laser beam, and are directly joined by optical contact as they are. As a result, the fundamental wavelength laser beam having a wavelength of 1064 nm can go straight without refraction, and the laser can be stably excited.

  As described above, the direct junction SHG element 110 in which the solid-state laser element 34 and the wavelength conversion element 35 are integrated is optically contacted by inclining the boundary surface between the solid-state laser element 34 and the wavelength conversion element 35 or a part thereof. And having a convex shape at the output side end of the directly bonded SHG element 110, it is possible to prevent interference between the fundamental wavelength laser beam having a wavelength of 1064 nm and the half wavelength laser beam having a wavelength of 532 nm, It is possible to prevent a decrease in conversion efficiency from a fundamental wavelength laser beam having a wavelength of 1064 nm to a half wavelength laser beam having a wavelength of 532 nm.

  Further, since the two structural members of the solid-state laser element 34 and the wavelength conversion element 35 are integrated, the green laser light source device 2 can be reduced in size and cost, and the green laser light source device 2 can be easily assembled. And the adjustment time can be reduced. Furthermore, the assembly accuracy is improved by integrating the constituent members, and the positional accuracy can be reduced.

  The laser light source device according to the present invention integrates a solid-state laser element and a wavelength conversion element, and provides an inclined surface at a part thereof to prevent interference between two laser beams having different wavelengths, thereby converting the conversion efficiency of the wavelength conversion element. It is effective as a laser light source device used as a light source of an image display device.

DESCRIPTION OF SYMBOLS 1 Image display apparatus 2 Green laser light source apparatus 3 Red laser light source apparatus 4 Blue laser light source apparatus 31 Semiconductor laser 34 Solid-state laser element 35 Wavelength conversion element 42, 46, 120 Film | membrane 80 Convex part 100 Inclined surface 110 Direct joining SHG element

Claims (4)

A semiconductor laser that outputs excitation laser light;
A solid-state laser element that outputs infrared laser light having a fundamental wavelength by the excitation laser light output from the semiconductor laser and a wavelength conversion element that converts the wavelength of the laser light output from the solid-state laser to ½ are directly used. With a directly bonded element,
The bonding surface of the direct bonding element is composed of an inclined surface inclined with respect to the optical axis of the infrared laser light, and the inclined laser beam reflected from the output surface of the wavelength conversion element is the inclined surface. A laser light source that reflects the wavelength-converted converted light and has a predetermined amount of inclination between the optical axis of the reflected converted light and the optical axis of the infrared laser light having the fundamental wavelength apparatus. The laser light source device according to claim 1, wherein the predetermined amount of inclination is 1 degree or more and 5 degrees or less. The laser light source device according to claim 1, wherein an output surface of the wavelength conversion element has a convex shape. 4. The laser light source device according to claim 1, wherein the semiconductor laser, the solid-state laser element, and the direct bonding element are integrally supported by one base.

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