JP6740713B2 - Light source device and projector - Google Patents

Description

The present invention relates to a light source device and a projector.

A light source device that includes a reflecting member that reflects laser light emitted from a semiconductor laser element arranged on a substrate and emits laser light in a direction different from the direction emitted from the semiconductor laser element has been proposed (for example, See Patent Document 1). Patent Document 1 describes a reflecting member that reflects laser light with a reflecting film made of a dielectric material.

JP, 2015-45843, A

However, although it is easy to design a reflection film made of a dielectric material as described above to reflect light incident at a predetermined incident angle, it is designed to reflect a plurality of lights having different incident angles. Things are difficult. Therefore, in the case of reflecting light that spreads at a predetermined angle such as laser light, there are cases where the reflective film made of a dielectric material cannot sufficiently reflect light. Further, since the reflection film made of a dielectric material is designed according to the wavelength of the reflected light, when the wavelength of the incident laser light changes from a predetermined wavelength, the reflectance for the laser light decreases and the unreflectable laser There was a problem of increased light.

As described above, in the reflection film made of the dielectric material, the reflection of the laser light becomes insufficient, and the ratio of the laser light emitted from the light source device to the laser light emitted from the semiconductor laser element may decrease. As a result, there is a problem that the light utilization efficiency of the light source device is reduced.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a light source device having a structure capable of suppressing a decrease in light utilization efficiency, and a projector including such a light source device. One

One aspect of a light source device of the present invention is a base substrate having a first surface, and a plurality of semiconductors arranged on the first surface and emitting laser light in a first direction along the first surface. A laser element, a frame-shaped joining frame joined to the first surface and surrounding the plurality of semiconductor laser elements, and a translucent member facing the plurality of semiconductor laser elements and fixed to the joining frame. A prism having an incident surface on which the laser light emitted from each of the plurality of semiconductor laser elements is incident, and a reflecting surface for reflecting at least a part of the laser light incident from the incident surface, and totally reflected by the reflecting surface. And an optical member provided on the translucent member for changing the traveling direction of the laser light emitted from the prism, and the reflecting surface has the base of natural logarithm e as the incident surface. Is arranged so as to totally reflect the laser light having a light intensity of 1/e ² or more of the center intensity of the laser light incident on the prism from, the reflecting surface is formed into a flat surface, and the optical member is The reflecting surface, which is separate from the translucent member, receives all laser light that enters the reflecting surface at the smallest incident angle among the laser light whose light intensity is 1/e ² or more of the central intensity. It is characterized in that it is provided with an inclination angle so as to be reflected.

According to one aspect of the light source device of the present invention, a plurality of laser beams having different emission angles can be easily reflected only by designing the inclination angle of the reflecting surface. In addition, the total reflection condition by the reflecting surface does not substantially change depending on the wavelength of the laser light, and suppresses the reflectance of the reflecting surface from decreasing even when the wavelength of the laser light changes from a predetermined wavelength. it can. With this, it is possible to reduce light that is not reflected in the laser light emitted from the semiconductor laser element, and it is possible to suppress a decrease in light utilization efficiency of the light source device.

A configuration may further include an optical member that changes the traveling direction of the laser light emitted from the prism after being totally reflected by the reflecting surface.
According to this configuration, even when the traveling direction of the laser light emitted from the prism cannot be set to the desired direction, the traveling direction of the laser light emitted from the light source device can be set to the desired direction by the optical member. it can.

A plurality of the semiconductor laser elements, a frame-shaped joining frame that is joined to the first surface and surrounds the semiconductor laser element, and a translucent member that faces the semiconductor laser element and is fixed to the joining frame. , May be further provided.
According to this configuration, it is possible to obtain a greater effect of suppressing a decrease in light utilization efficiency of the light source device.

The semiconductor laser device includes a first semiconductor laser device and a second semiconductor laser device, and the prism is a first prism on which laser light emitted from the first semiconductor laser device is incident. And a second prism on which the laser light emitted from the second semiconductor laser element is incident, the first prism and the second prism being formed integrally with the translucent member. The first semiconductor laser element and the second semiconductor laser element emit laser light in opposite directions, and the incident surface of the first prism and the incident surface of the second prism are different from each other. The reflecting surface of the first prism and the reflecting surface of the second prism may face each other.
In this configuration, when the reflective film is provided on the reflective surface, the labor and cost of manufacturing the light source device may increase. On the other hand, according to one aspect of the light source device of the present invention, since the reflecting surface is arranged so that the laser light is totally reflected, it is not necessary to form a reflecting film. As a result, it is possible to suppress the labor and cost for manufacturing the light source device from increasing.

The semiconductor substrate may be housed by the base substrate, the bonding frame, and the translucent member, and a sealed housing space may be provided.
With this configuration, it is possible to prevent the semiconductor laser element from deteriorating.

One aspect of a projector of the present invention includes the above light source device, a light modulation device that modulates light emitted from the light source device, and a projection optical system that projects light modulated by the light modulation device. It is characterized by being provided.

According to one aspect of the projector of the present invention, it is possible to suppress a decrease in light utilization efficiency in the light source device, and thus it is possible to obtain a projector having excellent optical characteristics.

A wavelength conversion element that is excited by light emitted from the light source device and emits fluorescent light may be further provided.
With this configuration, the light emitted from the light source device can be converted into fluorescent light.

It is a figure which shows the optical system of the projector of 1st Embodiment. It is a perspective view which shows the light source device of 1st Embodiment. It is a figure which shows the light source device of 1st Embodiment, Comprising: It is an IV-IV sectional perspective view of FIG. It is a figure which shows the light source device of 1st Embodiment, Comprising: It is IV-IV sectional drawing of FIG. It is a figure which shows the light source device of 1st Embodiment, Comprising: It is a partially expanded view of FIG. 3 is a graph showing a light intensity distribution of laser light emitted from the semiconductor laser device of the first embodiment. It is a figure for demonstrating the conditions which the laser beam which injects into a reflective surface is totally reflected. It is a graph which shows the relationship between an incident angle and a refraction angle. It is sectional drawing which shows the part of the light source device of 2nd Embodiment. It is sectional drawing which shows the part of the light source device of 3rd Embodiment. It is a figure for demonstrating the case where a reflection film and an antireflection film are formed in the prism of 3rd Embodiment.

Hereinafter, a light source device and a projector according to an embodiment of the present invention will be described with reference to the drawings. The scope of the present invention is not limited to the following embodiments and can be arbitrarily changed within the scope of the technical idea of the present invention. Further, in the following drawings, the scale and the number of each structure may be different from the scale and the number of the actual structure in order to make each structure easy to understand.

<First Embodiment>
FIG. 1 is a diagram showing an optical system of a projector 1000 of this embodiment. As shown in FIG. 1, the projector 1000 includes an illumination device 100, a color separation light guide optical system 200, a liquid crystal light modulation device (light modulation device) 400R, a liquid crystal light modulation device (light modulation device) 400G, and a liquid crystal. An optical modulator (optical modulator) 400B, a cross dichroic prism 500, and a projection optical system 600 are provided.

The illumination device 100 includes a light source device 10, a condensing optical system 20, a wavelength conversion element 30, a collimating optical system 60, a first lens array 120, a second lens array 130, a polarization conversion element 140, and a superposition. And a lens 150.

The light source device 10 emits blue light B (peak of emission intensity: about 445 nm) as excitation light of the wavelength conversion element 30. The light source device 10 will be described in detail later.

The condensing optical system 20 includes a first lens 21 and a second lens 22. The condensing optical system 20 is arranged in the optical path from the light source device 10 to the wavelength conversion element 30, and causes the blue light B to be incident on the phosphor layer 42 described later in a substantially condensed state. The first lens 21 and the second lens 22 are convex lenses.

The wavelength conversion element 30 includes a motor 50, a disc 40, a phosphor layer 42, and a dichroic film 44. The disc 40 can be rotated by a motor 50. The disc 40 is made of a material that transmits the blue light B. As the material of the disc 40, for example, quartz glass, crystal, sapphire, optical glass, transparent resin, or the like can be used.

The phosphor layer 42 is provided on the disc 40 along the circumferential direction of the disc 40. The phosphor layer 42 is excited by blue light having a wavelength of about 445 nm and emits fluorescent light composed of red light and green light. The phosphor layer 42 is, for example, a layer containing (Y,Gd) ₃ (Al,Ga) ₅ O ₁₂ :Ce, which is a YAG-based phosphor.

The dichroic film 44 is provided between the phosphor layer 42 and the disc 40. The dichroic film 44 transmits the blue light B and reflects the fluorescent light emitted from the phosphor layer 42.

The blue light B from the light source device 10 enters the phosphor layer 42 from the side of the disc 40. In the present embodiment, the phosphor layer 42 converts a part of the blue light B from the light source device 10 into a fluorescent light composed of the red light R and the green light G, and converts the remaining part of the blue light B. Pass without. Thereby, the wavelength conversion element 30 emits light including the red light R, the green light G, and the blue light B toward the side opposite to the side on which the blue light B emitted from the light source device 10 is incident. ..

The collimating optical system 60 includes a first lens 62 and a second lens 64, and substantially collimates the light from the wavelength conversion element 30. The first lens 62 and the second lens 64 are convex lenses.

The first lens array 120 has a plurality of first small lenses 122 for splitting the light from the collimating optical system 60 into a plurality of partial light fluxes. The plurality of first small lenses 122 are arranged in a matrix in a plane orthogonal to the illumination optical axis 100ax.

The second lens array 130 has a plurality of second small lenses 132 corresponding to the plurality of first small lenses 122 of the first lens array 120. The second lens array 130, together with the superimposing lens 150, forms an image of each first small lens 122 of the first lens array 120 in the vicinity of the image forming area of each liquid crystal light modulator 400R, 400G, 400B. The plurality of second small lenses 132 are arranged in a matrix in a plane orthogonal to the illumination optical axis 100ax.

The polarization conversion element 140 converts each partial light flux split by the first lens array 120 into linearly polarized light. The polarization conversion element 140 transmits one linearly polarized light component of the polarized light components included in the light from the wavelength conversion element 30 as it is, and reflects the other linearly polarized light component in a direction perpendicular to the illumination optical axis 100ax. Layer, a reflective layer that reflects the other linearly polarized light component reflected by the polarization separation layer in a direction parallel to the illumination optical axis 100ax, and the other linearly polarized light component reflected by the reflective layer into one linearly polarized light component And a retardation plate that does.

The superimposing lens 150 condenses each partial light flux from the polarization conversion element 140 and superimposes it on the vicinity of the image forming area of each liquid crystal light modulator 400R, 400G, 400B. The first lens array 120, the second lens array 130, and the superimposing lens 150 constitute an integrator optical system that makes the in-plane light intensity distribution of the light from the wavelength conversion element 30 uniform in the image forming area.

The color separation/light guide optical system 200 includes a dichroic mirror 210, a dichroic mirror 220, a reflection mirror 230, a reflection mirror 240, a reflection mirror 250, a relay lens 260, and a relay lens 270. The color separation/light guide optical system 200 separates the light from the lighting device 100 into red light R, green light G, and blue light B, and red light R, green light G, and blue light B correspond to liquid crystal light modulation, respectively. Light is guided to the devices 400R, 400G, and 400B.

A condenser lens 300R is arranged between the color separation/light guide optical system 200 and the liquid crystal light modulator 400R. A condenser lens 300G is arranged between the color separation/light guide optical system 200 and the liquid crystal light modulator 400G. A condenser lens 300B is arranged between the color separation/light guide optical system 200 and the liquid crystal light modulator 400B.

The dichroic mirror 210 is a dichroic mirror that transmits a red light component and reflects a green light component and a blue light component. The dichroic mirror 220 is a dichroic mirror that reflects a green light component and transmits a blue light component.

The red light R that has passed through the dichroic mirror 210 is reflected by the reflection mirror 230, passes through the condenser lens 300R, and enters the image forming area of the liquid crystal light modulation device 400R for red light. The green light G reflected by the dichroic mirror 210 is further reflected by the dichroic mirror 220, passes through the condenser lens 300G, and enters the image forming area of the liquid crystal light modulation device 400G for green light.

The blue light B that has passed through the dichroic mirror 220 passes through the relay lens 260, the reflection mirror 240, the relay lens 270, the reflection mirror 250, and the condenser lens 300B and is incident on the image forming area of the liquid crystal light modulation device 400B for blue light.

The liquid crystal light modulation device 400R, the liquid crystal light modulation device 400G, and the liquid crystal light modulation device 400B modulate the incident color light according to image information to form a color image. Although not shown, an incident-side polarization plate is arranged between each of the condenser lenses 300R, 300G, 300B and each of the liquid crystal light modulators 400R, 400G, 400B. An exit-side polarization plate is arranged between each of the liquid crystal light modulators 400R, 400G and 400B and the cross dichroic prism 500.

The cross dichroic prism 500 combines the image lights emitted from the liquid crystal light modulation device 400R, the liquid crystal light modulation device 400G, and the liquid crystal light modulation device 400B to form a color image. The cross dichroic prism 500 has a substantially square shape in a plan view in which four right-angle prisms are bonded together, and a dielectric multilayer film is formed on a substantially X-shaped interface where the right-angle prisms are bonded together.

The color image emitted from the cross dichroic prism 500 is enlarged and projected by the projection optical system 600 to form an image on the screen SCR.

Next, the light source device 10 of this embodiment will be described in detail. FIG. 2 is a perspective view showing the light source device 10. FIG. 3 is a view showing the light source device 10 and is a cross-sectional view taken along line IV-IV of FIG. FIG. 4 is a view showing the light source device 10 and is a sectional view taken along line IV-IV of FIG. FIG. 5 is a diagram showing the light source device 10 and is a partially enlarged view of FIG. 4. In FIG. 5, the illustration of the translucent member 112 is omitted.

As shown in FIGS. 1 to 4, the light source device 10 includes a base substrate 11, a cooler 70, a plurality of semiconductor laser elements 110, a bonding frame 107, a plurality of electrode portions 109A, and a plurality of electrode portions 109B. And a joining portion 80, a translucent member 112, and a plurality of prisms 113.

The base substrate 11 is a plate having a first surface 11a and a second surface 11b opposite to the first surface 11a. The first surface 11a is the surface of the base substrate 11 shown on the upper side in FIGS. 2 to 4. The second surface 11b is the surface shown on the lower side in FIGS. 2 to 4. In the state where the base substrate 11 is joined to the joining frame 107 by the joining portion 80 shown in FIGS. 2 to 4, the first surface 11a and the second surface 11b are flat. The base substrate 11 has, for example, a rectangular plate shape.

In the XYZ orthogonal coordinate system shown in each drawing, the Z-axis direction is a direction parallel to the thickness direction of the base substrate 11. The X-axis direction and the Y-axis direction are directions that are orthogonal to the Z-axis direction and are also orthogonal to each other. The X-axis direction is a direction parallel to the longitudinal direction of the base substrate 11. The Y-axis direction is a direction parallel to the lateral direction of the base substrate 11.

In the following description, the direction parallel to the thickness direction (Z-axis direction) of the base substrate 11 may be simply referred to as “thickness direction” unless otherwise specified, and the longitudinal direction of the base substrate 11 (X-axis direction). The direction parallel to is sometimes referred to simply as the “longitudinal direction”, and the direction parallel to the lateral direction (Y-axis direction) of the base substrate 11 may be simply referred to as the “lateral direction”.

The base substrate 11 is formed with a through hole 11c penetrating the base substrate 11 in the thickness direction (Z-axis direction). The through holes 11c are formed at the four corners of the base substrate 11, respectively, as shown in FIG. The through hole 11c has a circular shape in a plan view. For example, a screw that fixes the base substrate 11 to the housing of the projector 1000 is passed through the through hole 11c. As the base substrate 11, it is preferable to use a metal having a high thermal conductivity such as copper in order to efficiently dissipate the heat of the semiconductor laser device 110.

As shown in FIG. 1, the cooler 70 is fixed to the second surface 11 b of the base substrate 11 and cools the base substrate 11. In this embodiment, the cooler 70 is a heat sink having a plurality of fins. Note that the cooler 70 is not shown in FIGS. 2 to 5.

The plurality of semiconductor laser elements 110 are arranged on the first surface 11a, as shown in FIG. The plurality of semiconductor laser elements 110 are arranged in an array. In the present embodiment, the semiconductor laser device 110 is arranged such that a row in which five semiconductor laser devices 110 are arranged in the lateral direction (Y-axis direction) is arranged in five rows in the longitudinal direction (X-axis direction). Has been done. In the following description, the rows in which the five semiconductor laser elements 110 are arranged along the lateral direction are referred to as light emitting element rows M1 to M5 (see FIG. 3). When the light emitting element rows M1 to M5 are not distinguished, the light emitting element rows M1 to M5 are collectively referred to as the light emitting element row M.

In the present embodiment, the total number of semiconductor laser elements 110 is 25. The plurality of semiconductor laser devices 110 are arranged at predetermined intervals along the longitudinal direction (X-axis direction) and the lateral direction (Y-axis direction).

As shown in FIG. 5, the semiconductor laser device 110 emits laser light L in a first direction along the first surface 11a. In this embodiment, the first direction is the longitudinal direction (X-axis direction). The semiconductor laser device 110 includes a submount 103 and a laser light source 102. The submount 103 is formed on the first surface 11a. The submount 103 has, for example, a rectangular shape in a plan view. The material of the submount 103 is mainly ceramics such as aluminum nitride and alumina.

The laser light source 102 is mounted on the submount 103. The laser light L emitted from the laser light source 102 is, for example, blue light having a wavelength of 445 nm. The laser light source 102 may be a laser light source that emits blue light having a wavelength other than 445 nm (for example, 460 nm).

In the present embodiment, the laser light source 102 emits the laser light L toward one side (−X side) in the longitudinal direction (X axis direction). The light emitting surface 102a of the laser light source 102 from which the laser light L is emitted is substantially coincident with the side surface 103a on one side in the longitudinal direction of the submount 103, for example.

The laser light L emitted from the laser light source 102 is emitted with a predetermined spread. That is, the laser light L emitted from the laser light source 102 includes a plurality of laser lights inclined with respect to the optical axis LX of the laser light source 102. The cross-section (YZ cross-section) that is orthogonal to the optical axis LX of the laser light L is, for example, a circular shape centered on the optical axis LX.

In this specification, the phrase “the semiconductor laser element emits laser light in the first direction” includes that the optical axis of the laser light emitted from the semiconductor laser element with a predetermined spread is parallel to the first direction. .. In the present embodiment, the optical axis LX of the laser light L emitted from the semiconductor laser element 110 is parallel to the first direction (X-axis direction).

In the present specification, the first direction along the first surface includes not only the direction parallel to the first surface but also the direction inclined within a predetermined angle range with respect to the first surface. As an example, the first direction along the first surface includes a direction inclined with respect to the first surface within a range of ±15°.

The joining frame 107 is joined to the first surface 11a, as shown in FIG. More specifically, the joint frame 107 is joined to the first surface 11a via the joint portion 80. As shown in FIG. 2, the joining frame 107 has a frame shape surrounding the plurality of semiconductor laser elements 110. In the present embodiment, the joint frame 107 has a rectangular frame shape that is long in the longitudinal direction (X-axis direction) of the base substrate 11.

The joining frame 107 includes a pair of side walls 107a extending in the longitudinal direction (X axis direction) and a pair of side walls 107b extending in the lateral direction (Y axis direction). The side wall 107a on one side (+Y side) is provided with an electrode portion 109A, and the side wall 107a on the other side (−Y side) is provided with an electrode portion 109B. The electrode portion 109A and the electrode portion 109B are provided as a pair for each of the light emitting element rows M1 to M5. Although illustration is omitted, the electrode portion 109A is electrically connected to the anode of the laser light source 102, and the electrode portion 109B is electrically connected to the cathode of the laser light source 102. The material of the joint frame 107 is, for example, ceramics, kovar, or the like.

As shown in FIG. 4, the joint portion 80 joins the base substrate 11 and the joint frame 107. In the present embodiment, the joint portion 80 is interposed between the base substrate 11 and the joint frame 107. The joining portion 80 is a portion formed when the base substrate 11 and the joining frame 107 are joined by brazing, for example. The brazing material forming the joint portion 80 is preferably an inorganic material such as a metal material. This is because outgas is less likely to be generated at the time of bonding, and it is possible to suppress the deterioration of the semiconductor laser device 110 due to the adherence of outgas. In the present embodiment, the brazing material forming the joint portion 80 is, for example, silver brazing. The method of joining the base substrate 11 and the joining frame 107 is not particularly limited, and any joining method other than brazing may be used.

The translucent member 112 faces the plurality of semiconductor laser elements 110 and is fixed to the joint frame 107. The translucent member 112 is fixed to the upper surface 107c of the joint frame 107 on the opposite side (+Z side) of the base substrate 11. The material for fixing the joint frame 107 and the base substrate 11 is preferably an inorganic material such as a metal material as in the joint portion 80. This is because outgas is less likely to be generated at the time of bonding, and it is possible to suppress the deterioration of the semiconductor laser device 110 due to the adherence of outgas. In the present embodiment, the translucent member 112 is joined to the joining frame 107 using, for example, low melting point glass.

The translucent member 112 closes the opening on one side (+Z side) of the joint frame 107. As a result, the base substrate 11, the joint frame 107, and the translucent member 112 provide a storage space K in which a plurality of semiconductor laser elements 110 are stored and sealed. The storage space K is filled with, for example, an inert gas or dry air. The storage space K may be in a depressurized state. The depressurized state means a state of a space filled with a gas having a pressure lower than normal atmospheric pressure. In this definition, the gas may be an inert gas or dry air. By sealing the storage space K in this manner, it is possible to prevent moisture or outside air from entering the storage space K, and it is possible to suppress deterioration of the semiconductor laser element 110.

As shown in FIG. 2, the translucent member 112 has a rectangular shape along the outer shape of the joint frame 107. The translucent member 112 is made of a translucent substrate that transmits the laser light L emitted from the semiconductor laser element 110. The material of the translucent member 112 is glass, quartz, resin or the like.

Another member (intermediate member) may be interposed between the translucent member 112 and the joint frame 107. When the intermediate member is used, the translucent member 112 and the intermediate member are joined by, for example, low melting point glass, and the joining frame 107 and the intermediate member are joined by, for example, low melting point glass.

As shown in FIG. 4, the plurality of prisms 113 are integrally formed on the lower surface 112 a of the translucent member 112 on the base substrate 11 side (−Z side). As shown in FIG. 2, the prism 113 is provided for each of the light emitting element rows M1 to M5 provided on the base substrate 11, and the laser emitted from the plurality of semiconductor laser elements 110 forming the corresponding light emitting element row M. It is located on the optical path of the light L. The prism 113 extends in the lateral direction (Y-axis direction) along the light emitting element array M. As shown in FIG. 5, the cross section (ZX cross section) of the prism 113 orthogonal to the extending direction is, for example, a triangular shape.

The prism 113 is arranged on the optical path of the laser light L emitted from the laser light source 102, that is, the semiconductor laser element 110. The prism 113 is reflected by the incident surface 113a on which the laser light L emitted from the semiconductor laser element 110 is incident, the reflective surface 113b that reflects at least a part of the laser light L incident from the incident surface 113a, and the reflective surface 113b. The laser beam L is emitted from the prism 113, and the emission surface 113c.

The incident surface 113a is a surface of the prism 113 on the semiconductor laser element 110 side (+X side). The incident surface 113a faces the light emitting surface 102a of the laser light source 102. In the present embodiment, the incident surface 113a is perpendicular to the first surface 11a and is orthogonal to the longitudinal direction (X axis direction). As shown in FIG. 4, the end of the incident surface 113a on the opposite side (+Z side) from the first surface 11a is connected to the lower surface 112a of the translucent member 112. Although illustration is omitted, an antireflection film is formed on the incident surface 113a.

As shown in FIG. 5, the reflecting surface 113b is a surface of the prism 113 on the opposite side (−X side) to the semiconductor laser element 110. The reflecting surface 113b is an inclined surface that is inclined with respect to the first surface 11a and the incident surface 113a. The reflective surface 113b is located on the side (−X side) away from the semiconductor laser element 110 in the longitudinal direction (X axis direction) as it goes toward the side (+Z side) away from the first surface 11a in the thickness direction (Z axis direction). To position. An end of the reflecting surface 113b on the first surface 11a side (−Z side) is connected to an end of the incident surface 113a on the first surface 11a side. As shown in FIG. 4, the end of the reflective surface 113b on the opposite side (+Z side) from the first surface 11a is connected to the lower surface 112a of the translucent member 112.

When the base of the natural logarithm is e, the reflecting surface 113b totally reflects the laser light L having a light intensity of 1/e ² or more of the central intensity of the laser light L incident on the prism 113 from the incident surface 113a. Are arranged as follows. The central intensity is the maximum value of the light intensity of the laser light L. When defining the beam diameter of the laser light L, a method is often used in which the diameter of the laser light L in the range of 1/e ² or more of the central intensity of the laser light L is used as the beam diameter. That is, the laser light L having a light intensity of 1/e ² or more of the central intensity is, among the laser light L emitted from the semiconductor laser element 110, laser light that can be effectively used as light emitted from the light source device 10. It is L.

FIG. 6 is a graph showing the light intensity distribution of the laser light L emitted from the semiconductor laser device 110. In FIG. 6, the vertical axis represents the light intensity of the laser light L, and the horizontal axis represents the radial position with the center position C of the irradiation area IA1 as the center. The light intensity of the laser light L shown on the vertical axis in FIG. 6 is a normalized intensity when the maximum light intensity of the laser light L is 1.

The distribution of the light intensity of the laser light L is a Gaussian distribution as shown in FIG. An area where the light intensity of the laser light L is 1/e ² of the maximum light intensity is irradiated is referred to as an irradiation area IA1 of the laser light L. The irradiation area IA1 is, as shown in FIG. 5, an irradiation area of the laser beam L on the incident surface 113a. In the present embodiment, the light intensity is maximum at the center position C of the irradiation area IA1. That is, the light intensity at the center position C of the irradiation area IA1 is the center intensity of the laser light L.

In FIG. 5, of the laser light L passing through the irradiation area IA1, the laser light Ld passing through the end portion of the irradiation area IA1 on the first surface 11a side (−Z side) and the first surface 11a of the irradiation area IA1. And laser light Lu passing through the end portion on the opposite side (+Z side) and laser light Lc passing through the center position C of the irradiation area IA1. The laser lights Ld and Lu are laser lights whose light intensity is 1/e ^{2 of the} central intensity. The laser light Lc is a laser light that overlaps the optical axis LX and has a central light intensity, that is, a maximum light intensity.

The laser light Ld is a laser light having the smallest incident angle θ3 with respect to the reflection surface 113b among the laser light L having a light intensity of 1/e ² or more of the central intensity. That is, if the reflection surface 113b is arranged so that the laser light Ld is totally reflected by the reflection surface 113b, the laser light L whose light intensity is 1/e ² or more of the central intensity is totally reflected by the reflection surface 113b. be able to.

FIG. 7 is a diagram for explaining the conditions under which the laser light L incident on the reflecting surface 113b is totally reflected. When the incident angle θ3 with respect to the reflection surface 113b is smaller than a predetermined value, as indicated by the dashed-dotted arrow in FIG. It is emitted to the outside of the prism 113. On the other hand, as shown by a solid arrow in FIG. 7, when the incident angle θ3 is equal to or larger than the predetermined value, the laser light L is totally reflected by the reflecting surface 113b.

FIG. 8 is a graph showing the relationship between the incident angle θ3 and the refraction angle θ4. In FIG. 8, the horizontal axis represents the incident angle θ3, and the vertical axis represents the refraction angle θ4. FIG. 8 shows the relationship between the incident angle θ3 and the refraction angle θ4 when the atmosphere outside the prism 113 is air. In FIG. 8, the refractive index of air is 1.0 and the refractive index of the prism 113 is 1.7. The atmosphere outside the prism 113 is the atmosphere inside the storage space K.

As shown in FIG. 8, it was found that the refraction angle θ4 was 90° when the incident angle θ3 was about 36°. Accordingly, in the case of the condition of FIG. 8, the light intensity is 1/e ² or more of the central intensity by arranging the reflection surface 113b so that the incident angle θ3 of the laser light Ld with respect to the reflection surface 113b is about 36° or more. It has been found that the laser light L that becomes the above can be totally reflected by the reflecting surface 113b. In this way, the condition of the incident angle θ3 of the laser light Ld can be obtained according to the refractive index of the prism 113, the atmosphere outside the prism 113, that is, the refractive index of the atmosphere in the storage space K, and the like.

When arranging the reflecting surface 113b based on the conditions of FIG. 8, as an example, the inclination angle θR (see FIG. 5) of the reflecting surface 113b with respect to the incident surface 113a is set to 45°. At this time, the emission angle θ1 of the laser light Ld is set to 8.5°. The laser light Ld entering the prism 113 from the incident surface 113a is refracted at the refraction angle θ2 on the incident surface 113a. When the radiation angle θ1 is 8.5°, the refraction angle θ2 is, for example, 5°. The laser light Ld refracted in this way enters the reflecting surface 113b at an incident angle θ3 of 40°. Therefore, the total reflection condition shown in FIG. 8 is satisfied, and the laser light Ld is totally reflected by the reflecting surface 113b.

As shown in FIG. 5, the laser lights Lc and Lu enter the reflecting surface 113b at an incident angle θ3 larger than the laser light Ld. Therefore, when the laser light Ld is totally reflected by the reflecting surface 113b, Lc and Lu are also totally reflected by the reflecting surface 113b. In this embodiment, the laser light Lc overlapping the optical axis LX is designed to enter the reflecting surface 113b at an incident angle θ3 of 45°. Therefore, the laser light Lc is bent by 90° and reflected by the reflecting surface 113b. Thereby, in the light source device 10, the laser light L emitted from the semiconductor laser element 110 can be emitted in a direction (Z-axis direction) perpendicular to the first surface 11a. The laser light L reflected by the reflection surface 113b is emitted from the prism 113 via the emission surface 113c.

The reflecting surface 113b may or may not totally reflect the laser light whose light intensity is smaller than 1/e ^{2 of the} central intensity.

The emission surface 113c is a surface (+Z side) opposite to the first surface 11a of the prism 113. The exit surface 113c is parallel to the first surface 11a and is orthogonal to the entrance surface 113a. The exit surface 113c connects the end of the entrance surface 113a on the opposite side (+Z side) of the first surface 11a and the end of the reflecting surface 113b on the opposite side (+Z side) of the first surface 11a. .. As shown in FIG. 4, the emission surface 113c contacts the lower surface 112a of the translucent member 112. In the present embodiment, since the prism 113 is formed integrally with the translucent member 112, the emission surface 113c is a virtual boundary surface between the translucent member 112 and the prism 113.

In FIG. 5, the transparent member 112 is not shown, and the laser beams Ld and Lu are refracted and emitted to the outside at the emission surface 113c. However, in the case of the present embodiment, In addition, the laser light L is incident on the translucent member 112 from the emission surface 113c, and the laser lights Ld and Lu are refracted on the upper surface 112b of the translucent member 112 opposite to the prism 113 (+Z side). The light is emitted to the outside of the light source device 10.

According to the present embodiment, the prism 113 has the reflection surface 113b arranged so as to totally reflect the laser light L of which the light intensity is 1/e ² or more of the central intensity of the laser light L. Therefore, it is possible to easily reflect a plurality of laser beams having different emission angles θ1 only by designing the inclination angle θR of the reflecting surface 113b. Further, the total reflection condition by the reflecting surface 113b does not substantially change depending on the wavelength of the laser light L, and the reflectance of the reflecting surface 113b decreases even when the wavelength of the laser light L changes from a predetermined wavelength. Can be suppressed. As a result, the light that is not reflected in the laser light L emitted from the semiconductor laser element 110 can be reduced, and it is possible to prevent the light utilization efficiency of the light source device 10 from decreasing.

Further, when a plurality of semiconductor laser elements 110 are arranged as in the present embodiment, the variation in the wavelength of the laser light L emitted from each semiconductor laser element 110 is likely to be large, and the laser light L is emitted from each semiconductor laser element 110. It is more difficult to form the dielectric multi-layered film in response to the variation in the wavelength of the laser light L. On the other hand, according to the present embodiment, the laser light L can be totally reflected regardless of the wavelength of the laser light L. That is, the effect of this embodiment is particularly great in a light source device in which a plurality of semiconductor laser elements 110 are arranged, like the light source device 10 of this embodiment.

The light source device 10 of the present embodiment may be configured to include only one semiconductor laser element 110.

<Second Embodiment>
The second embodiment is different from the first embodiment in that an optical member 713 is provided. In addition, about the same structure as the said embodiment, description may be abbreviate|omitted by giving the same code|symbol suitably.

FIG. 9 is a cross-sectional view showing a part of the light source device 1010 of this embodiment. In FIG. 9, the illustration of the translucent member 112 is omitted. As shown in FIG. 9, the light source device 1010 includes an optical member 713.

The optical member 713 is arranged on the opposite side (+Z side) to the base substrate 11 of the prism 113. Although illustration is omitted, the optical member 713 is, for example, a prismatic member extending in the lateral direction (Y-axis direction). The shape of the cross section (ZX cross section) orthogonal to the extending direction of the optical member 713 is, for example, a triangular shape. In the present embodiment, the optical member 713 is, for example, a prism.

The optical member 713 may be arranged inside the storage space K or may be arranged outside the storage space K. When the optical member 713 is arranged in the storage space K, the optical member 713 is fixed to, for example, the lower surface 112a of the translucent member 112 on the storage space K side (−Z side). In this case, the prism 113 may be formed separately from the translucent member 112. When the optical member 713 is arranged outside the storage space K, the optical member 713 is fixed to the upper surface 112b of the translucent member 112, for example. The optical member 713 may be formed integrally with the translucent member 112, or may be formed separately.

The optical member 713 has a second entrance surface 713a and a second exit surface 713b. The second incident surface 713a is a surface of the optical member 713 on the prism 113 side (−Z side). The second incident surface 713a is, for example, a surface parallel to the first surface 11a and faces the exit surface 113c of the prism 113.

The second exit surface 713b is the surface of the optical member 713 on the opposite side (+Z side) to the prism 113. The second exit surface 713b is an inclined surface that is inclined with respect to the second entrance surface 713a. The second emission surface 713b is away from the first surface 11a in the thickness direction (Z-axis direction) (+Z side) as it goes toward the side closer to the semiconductor laser element 110 (+X side) in the longitudinal direction (X-axis direction). ) Located. The end of the second exit surface 713b on the opposite side (−X side) of the semiconductor laser element 110 in the longitudinal direction is connected to the end of the second incident surface 713a on the opposite side of the semiconductor laser element 110 in the longitudinal direction. ing.

The optical member 713 changes the traveling direction of the laser light L emitted from the prism 113 after being totally reflected by the reflecting surface 113b of the prism 113. More specifically, the laser light L emitted from the emission surface 113c of the prism 113 enters the optical member 713 through the second incident surface 713a. The laser light L incident on the optical member 713 is refracted at the second incident surface 713a and the second exit surface 713b, and the traveling direction is changed. In the present embodiment, the traveling direction of the laser light L emitted from the emission surface 113c of the prism 113 is a direction inclined with respect to the direction (Z-axis direction) perpendicular to the first surface 11a. The laser light L emitted from the emission surface 113c of the prism 113 is changed by the optical member 713 in a direction perpendicular to the first surface 11a.

The other configurations of the light source device 1010 are the same as the configurations of the light source device 10 of the first embodiment.

For example, when the reflecting surface 113b of the prism 113 is arranged so as to totally reflect the laser light L having a light intensity of 1/e ² or more of the central intensity, depending on the refractive index of the prism 113 and the emission angle θ1 of the laser light L, etc. May not allow the traveling direction of the laser light L emitted from the emission surface 113c to be a desired direction. In this case, the traveling direction of the laser light L emitted from the light source device cannot be set to a desired direction, and the optical characteristics of the light source device may deteriorate. In the case of the present embodiment, the desired direction is, for example, a direction perpendicular to the first surface 11a.

On the other hand, according to the present embodiment, since the optical member 713 can change the traveling direction of the laser light L emitted from the prism 113, the traveling direction of the laser light L emitted from the emission surface 113c. Even if the laser beam cannot be directed in the desired direction, the traveling direction of the laser light L emitted from the light source device 1010 can be directed in the desired direction. Therefore, according to this embodiment, the light source device 1010 having excellent optical characteristics can be obtained.

In the present embodiment, the optical member 713 is not particularly limited as long as it can change the traveling direction of the laser light L emitted from the prism 113. The optical member 713 may be, for example, a reflection plate or a lens.

<Third Embodiment>
The third embodiment is different from the first embodiment in that at least a pair of prisms and a semiconductor laser element face each other. In addition, about the same structure as the said embodiment, description may be abbreviate|omitted by giving the same code|symbol suitably.

FIG. 10: is sectional drawing which shows the part of the light source device 2010 of this embodiment. As shown in FIG. 10, in the light source device 2010, the semiconductor laser element includes a first semiconductor laser element 810 and a second semiconductor laser element 910.

The first semiconductor laser device 810 is the same as the semiconductor laser device 110 described in the first embodiment. The second semiconductor laser device 910 is the same as the semiconductor laser device 110 described in the first embodiment, except that the second semiconductor laser device 910 is arranged inverted in the longitudinal direction (X-axis direction).

The first semiconductor laser device 810 and the second semiconductor laser device 910 emit laser light L in opposite directions. In the present embodiment, the first semiconductor laser device 810 and the second semiconductor laser device 910 emit laser light L in directions facing each other. The first semiconductor laser device 810 emits the laser light L toward one side (−X side) in the longitudinal direction (X axis direction), similarly to the semiconductor laser device 110 of the first embodiment. The second semiconductor laser element 910 emits the laser light L toward the other side (+X side) in the longitudinal direction (X-axis direction).

In the light source device 2010, the prism includes a first prism 813 and a second prism 913. The first prism 813 is similar to the prism 113 described in the first embodiment. The second prism 913 is similar to the prism 113 described in the first embodiment, except that the second prism 913 is arranged so as to be inverted in the longitudinal direction (X-axis direction). The first prism 813 and the second prism 913 are formed integrally with the translucent member 112.

The laser light L emitted from the first semiconductor laser element 810 is incident on the first prism 813 from the incident surface 813a. The laser light L emitted from the second semiconductor laser device 910 is incident on the second prism 913 from the incident surface 913a. The incident surface 813a of the first prism 813 and the incident surface 913a of the second prism 913 face opposite sides. In the present embodiment, the incident surface 813a faces the opposite side (+X side) of the second prism 913, and the incident surface 913a faces the opposite side (−X side) of the first prism 813. That is, in the present embodiment, the incident surface 813a and the incident surface 913a are arranged so as not to face each other.

The laser light L incident on the first prism 813 is totally reflected by the reflecting surface 813b, as in the first embodiment. The laser light L that has entered the second prism 913 is totally reflected by the reflecting surface 913b, as in the first embodiment. In the present embodiment, the reflecting surface 813b of the first prism 813 and the reflecting surface 913b of the second prism 913 are opposed to each other.

FIG. 11 is an explanatory diagram illustrating a case where a reflection film and an antireflection film are formed on the prism of the present embodiment. As shown in FIG. 11, in the present embodiment, when the reflecting surface 913b of the second prism 913 is viewed along the normal direction of the reflecting surface 913b of the second prism 913 (the direction of the arrow in the figure). , At least a part of the incident surface 813a of the first prism 813 is visible. In this embodiment, the entire incident surface 813a of the first prism 813 is visible.

In the present specification, "at least a part of the incident surface of the first prism is visible" means that the incident surface is directly visible, and that an antireflection film or the like is formed on the incident surface. Including the case where the incident surface is visually recognizable, that is, the case where the antireflection film or the like is directly visible.

The other configurations of the light source device 2010 are the same as the configurations of the light source device 10 of the first embodiment.

For example, as shown in FIG. 11, when forming the reflection film 881 on each reflection surface, for example, a substance forming the reflection film 881 is vapor-deposited on each reflection surface along the normal direction of each reflection surface. The arrow in FIG. 11 indicates the normal direction of the reflecting surface 913b of the second prism 913, and indicates the vapor deposition direction when the reflecting film 881 is formed on the reflecting surface 913b. It is easy to form a uniform reflective film by vapor-depositing the material forming the reflective film 881 on each reflective surface along the normal direction of each reflective surface.

Here, when the reflecting surface of a certain prism is viewed along the normal direction as in the present embodiment and the incident surface of the other prism is visible, a reflecting film 881 is formed on the reflecting surface of the certain prism. During vapor deposition, it is necessary to mask the incident surface of another prism. Specifically, as shown in FIG. 11, when the reflecting film 881 is formed on the reflecting surface 913b of the second prism 913, the first visible layer 913b is visible when the reflecting surface 913b is viewed along the normal direction. It is necessary to mask the incident surface 813a of the prism 813.

As described above, when the reflecting surface of one prism is viewed along the normal direction and the incident surface of another prism is visible, when the laser light L is reflected by the reflecting film 881, In the formation of the reflective film 881, there is a problem that it takes time and effort for masking, which increases the time and cost for manufacturing the light source device.

On the other hand, according to the present embodiment, the reflecting surfaces 813b and 913b are arranged so as to totally reflect the laser light L incident on each prism, so that the laser light L can be formed without forming the reflecting film 881. Can be reflected. Therefore, the labor for forming the reflective film 881 can be reduced, and the labor and cost for manufacturing the light source device 2010 can be suppressed from increasing.

Further, as in the present embodiment, the first semiconductor laser element 810 and the second semiconductor laser element 910 emit laser light L in mutually opposite directions, and the reflection surfaces 813b and 913b of each prism face each other. In this case, the reflecting surface and the incident surface are easily visible at the same time when viewed along the vapor deposition direction. Therefore, the effect of reducing the labor for forming the reflection film 881 described above is that the first semiconductor laser element 810 and the second semiconductor laser element 910 emit the laser light L in opposite directions, and each reflection of each prism. It is particularly large when the surfaces 813b and 913b face each other.

The light source device 2010 of the present embodiment may be configured to include only one first semiconductor laser element 810 and one second semiconductor laser element 910 as a plurality of semiconductor laser elements. Moreover, the plurality of semiconductor laser elements may include at least one pair of the first semiconductor laser element 810 and the second semiconductor laser element 910.

Further, when the reflecting surface 913b of the second prism 913 is viewed along the normal direction of the reflecting surface 913b of the second prism 913, at least a part of the incident surface 813a of the first prism 813 can be visually recognized. If so, the first prism 813 and the second prism 913 may be arranged such that each incident surface and each reflective surface face the same direction. In this case, the first semiconductor laser element 810 and the second semiconductor laser element 910 may emit the laser light L in the same direction. Further, in this case, for example, the angles of the reflecting surface and the incident surface of each prism with respect to the first surface 11a may be different from each other.

Further, the first semiconductor laser element 810 emits the laser light L toward the other side (+X side) in the longitudinal direction (X axis direction), and the second semiconductor laser element 910 emits the laser beam L in the longitudinal direction (X axis direction). ), the laser light L may be emitted toward one side (-X side). At this time, the reflecting surface 813b of the first prism 813 and the reflecting surface 913b of the second prism 913 face opposite sides. That is, the reflecting surface 813b faces the opposite side (+X side) of the second prism 913, and the reflecting surface 913b faces the opposite side (−X side) of the first prism 813. Therefore, the reflecting surface 813b and the reflecting surface 913b are arranged so as not to face each other. On the other hand, at this time, the incident surface 813a of the first prism 813 and the incident surface 913a of the second prism 913 are opposed to each other. Also in this case, the reflecting surface and the entrance surface are easily visible at the same time when viewed along the vapor deposition direction, and the effect of reducing the labor for forming the above-described reflecting film 881 is particularly great.

In each of the above-mentioned embodiments, each incident surface may not be provided with an antireflection film, or each reflective surface may be provided with a reflective film.

Further, in each of the above embodiments, the prism may be formed as a separate body from the translucent member.

Further, in each of the above embodiments, the joint frame 107 and the translucent member 112 may not be provided.

Further, in each of the above-described embodiments, an example in which the present invention is applied to a transmissive projector has been described, but the present invention can also be applied to a reflective projector. Here, the "transmissive type" means that the liquid crystal light modulation device is a type that transmits light. “Reflective” means that the liquid crystal light modulator is a type that reflects light.

Further, in each of the above-described embodiments, the projector 1000 including the three liquid crystal light modulation devices 400R, 400G, and 400B is illustrated, but a projector that displays a color image with one liquid crystal light modulation device, and four or more liquid crystal lights. It is also possible to apply to a projector that displays a color image with a modulator. A digital mirror device (DMD) may be used as the light modulator.

Further, the light source device of the present invention is not limited to the light source device of the projector, but can be applied to headlamps of automobiles, lighting equipment and the like.

Further, the above-described respective configurations can be appropriately combined within a range in which they do not contradict each other.

10, 1010, 2010... Light source device, 11... Base substrate, 11a... First surface, 30... Wavelength conversion element, 107... Bonding frame, 112... Translucent member, 110... Semiconductor laser element, 113... Prism, 113a , 813a, 913a... Incident surface, 113b, 813b, 913b... Reflecting surface, 400B, 400G, 400R... Liquid crystal light modulator (light modulator), 600... Projection optical system, 713... Optical member, 810... First semiconductor Laser element, 813... First prism, 910... Second semiconductor laser element, 913... Second prism, 1000... Projector, K... Storage space, L, Lc, Ld, Lu... Laser light

Claims (5)

A base substrate having a first surface,
A plurality of semiconductor laser elements arranged on the first surface and emitting laser light in a first direction along the first surface;
A frame-shaped joining frame joined to the first surface and surrounding the plurality of semiconductor laser elements;
A transparent member facing the plurality of semiconductor laser elements and fixed to the joint frame,
A prism having an incident surface on which laser light emitted from each of the plurality of semiconductor laser elements is incident, and a reflecting surface that reflects at least a part of the laser light incident from the incident surface,
And changing the traveling direction of the laser light emitted from the prism after being totally reflected by the reflecting surface, an optical member provided on the translucent member,
When the base of the natural logarithm is e, the reflecting surface totally reflects the laser light having a light intensity of 1/e ² or more of the central intensity of the laser light incident on the prism from the incident surface. Placed,
The reflective surface is formed into a flat surface,
The optical member is a separate body from the translucent member,
The reflecting surface is provided with an inclination angle so as to totally reflect the laser light whose light intensity is 1/e ² or more of the central intensity and which is incident on the reflecting surface at the smallest incident angle. A light source device characterized by the above. The semiconductor laser device includes a first semiconductor laser device and a second semiconductor laser device,
The prism includes a first prism on which the laser light emitted from the first semiconductor laser element is incident, and a second prism on which the laser light emitted from the second semiconductor laser element is incident.
Including,
The first prism and the second prism are formed integrally with the translucent member,
The first semiconductor laser device and the second semiconductor laser device emit laser light in mutually opposite directions,
The incident surface of the first prism and the incident surface of the second prism face each other, or the reflecting surface of the first prism and the reflecting surface of the second prism face each other. The light source device according to claim 1. The light source device according to claim 1, wherein the semiconductor laser element is housed by the base substrate, the bonding frame, and the translucent member, and a sealed housing space is provided. The light source device according to claim 1,
A light modulator for modulating the light emitted from the light source device;
A projection optical system for projecting the light modulated by the light modulator,
A projector comprising: The projector according to claim 4, further comprising a wavelength conversion element that is excited by light emitted from the light source device and emits fluorescent light.

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