JP2017212390A - Light-source device and projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-source device having a structure which can suppress a reduction in efficiency for light utilization.SOLUTION: A light-source device comprises: a base substrate 11 having a first face; a semiconductor laser element 110 being disposed on the first face and emitting laser light L in a first direction along the first face; and a prism 113 having an incident face 113a to which the laser light emitted from the semiconductor laser element is incident and a reflection surface 113b reflecting at least a part of the laser light incident from the incident face. When the base of a natural logarithm is denoted by "e", the reflection face is disposed so as to totally reflect the laser light having light intensity equal to or larger than 1/eof center intensity out of the laser light incident to the prism from the incident face.SELECTED DRAWING: Figure 5

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 disposed 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, 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, the reflection film made of the dielectric material as described above is designed so as to reflect a plurality of lights having different incident angles although it is easy to design to reflect the light incident at a predetermined incident angle. It is difficult. For this reason, when light that spreads at a predetermined angle, such as laser light, is reflected, the reflection film made of a dielectric material may not be able to sufficiently reflect the light. In addition, since the reflective film made of a dielectric material is designed according to the wavelength of the reflected light, if the wavelength of the incident laser light changes from a predetermined wavelength, the reflectance with respect to the laser light decreases, and the laser cannot be reflected. There was a problem that light increased.

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

  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 use efficiency, and a projector including such a light source device. One.

One aspect of the light source device of the present invention includes a base substrate having a first surface and a semiconductor laser element that is disposed on the first surface and emits laser light in a first direction along the first surface. And an incident surface on which laser light emitted from the semiconductor laser element is incident, and a prism having a reflective surface that reflects at least part of the laser light incident from the incident surface, the reflective surface being a natural surface When the base of the logarithm is e, the laser light that is incident on the prism from the incident surface is arranged so as to totally reflect the laser light whose light intensity is 1 / e ² or more of the central intensity. Features.

  According to one aspect of the light source device of the present invention, it is possible to easily reflect a plurality of laser beams having different emission angles 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 beam, and even when the wavelength of the laser beam changes from a predetermined wavelength, the reflectance of the reflecting surface is prevented from decreasing. it can. Thereby, the light which is not reflected among the laser lights inject | emitted from the semiconductor laser element can be reduced, and it can suppress that the light utilization efficiency of a light source device falls.

It is good also as a structure further equipped with the optical member which changes the advancing direction of the laser beam inject | emitted from the said prism after being totally reflected by the said reflective surface.
According to this configuration, even when the traveling direction of the laser light emitted from the prism cannot be a desired direction, the traveling direction of the laser light emitted from the light source device by the optical member can be set to a desired direction. it can.

A plurality of the semiconductor laser elements; a frame-shaped bonding frame that is bonded 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 bonding frame. It is good also as a structure further provided.
According to this structure, the effect which can suppress that the light utilization efficiency of a light source device falls can be acquired more largely.

The semiconductor laser element includes a first semiconductor laser element and a second semiconductor laser element, and the prism includes a first prism on which laser light emitted from the first semiconductor laser element is incident. A second prism on which laser light emitted from the second semiconductor laser element is incident, and the first prism and the second prism are formed integrally with the light-transmissive member. The first semiconductor laser element and the second semiconductor laser element emit laser beams in opposite directions, and the incident surface of the first prism and the incident surface of the second prism are The reflective surface of the first prism and the reflective surface of the second prism may be opposed to each other.
In this configuration, when a 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 beam is totally reflected, it is not necessary to form a reflecting film. Thereby, it can suppress that the effort and cost of manufacture of a light source device increase.

The base substrate, the joining frame, and the translucent member may house the semiconductor laser element and provide a sealed housing space.
According to this structure, it can suppress that a semiconductor laser element deteriorates.

  One aspect of the 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 providing.

  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 a projector having excellent optical characteristics can be obtained.

It is good also as a structure further provided with the wavelength conversion element which is excited by the light inject | emitted from the said light source device, and inject | emits fluorescence light.
According to 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 the IV-IV cross-section 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 the elements on larger scale of FIG. It is a graph which shows light intensity distribution of the laser beam inject | emitted from the semiconductor laser element of 1st Embodiment. It is a figure for demonstrating the conditions where the laser beam which injects into a reflective surface totally reflects. It is a graph shown about 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 reflecting 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 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. In the following drawings, the scale and number of each structure may be different from the scale and number of the actual structure in order to make each configuration easy to understand.

<First Embodiment>
FIG. 1 is a diagram illustrating an optical system of a projector 1000 according to the present 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. A light modulation device (light modulation device) 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, and a polarization conversion element 140. A lens 150.

  The light source device 10 emits blue light B (emission intensity peak: 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 disposed in the optical path from the light source device 10 to the wavelength conversion element 30 and causes the blue light B as a whole to be incident on a phosphor layer 42 described later in a substantially condensed state. The first lens 21 and the second lens 22 are constituted by 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 a material of the disc 40, for example, quartz glass, quartz, 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 composed of, for example, a layer containing (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ : Ce, which is a YAG 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 disk 40 side. In the present embodiment, the phosphor layer 42 converts part of the blue light B from the light source device 10 into fluorescent light composed of red light R and green light G, and converts the remaining part of the blue light B. Pass without. Thereby, the wavelength conversion element 30 emits the 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 makes the light from the wavelength conversion element 30 substantially parallel. 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 dividing the light from the collimating optical system 60 into a plurality of partial light beams. 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 forms an image of each first small lens 122 of the first lens array 120 together with the superimposing lens 150 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 beam divided by the first lens array 120 into linearly polarized light. The polarization conversion element 140 transmits one linear polarization component of the polarization component included in the light from the wavelength conversion element 30 as it is, and reflects the other linear polarization component in a direction perpendicular to the illumination optical axis 100ax. A reflection 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 is converted into one linearly polarized light component. A phase difference plate.

  The superimposing lens 150 condenses the partial light beams from the polarization conversion element 140 and superimposes them in the vicinity of the image forming areas of the liquid crystal light modulation devices 400R, 400G, and 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 region.

  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 illumination device 100 into red light R, green light G and blue light B, and the liquid crystal light modulation to which the red light R, green light G and blue light B respectively correspond. The light is guided to the devices 400R, 400G, and 400B.

  A condensing lens 300R is disposed between the color separation light guide optical system 200 and the liquid crystal light modulation device 400R. A condensing lens 300G is disposed between the color separation light guide optical system 200 and the liquid crystal light modulation device 400G. A condensing lens 300B is disposed between the color separation light guide optical system 200 and the liquid crystal light modulation device 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 region 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 enters the image forming area of the liquid crystal light modulation device 400B for blue light through the relay lens 260, the reflection mirror 240, the relay lens 270, the reflection mirror 250, and the condenser lens 300B.

  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, incident-side polarizing plates are disposed between the condenser lenses 300R, 300G, and 300B and the liquid crystal light modulators 400R, 400G, and 400B, respectively. In addition, an exit-side polarizing plate is disposed between each of the liquid crystal light modulation devices 400R, 400G, and 400B and the cross dichroic prism 500.

  Cross dichroic prism 500 combines the image light emitted from each of liquid crystal light modulation device 400R, liquid crystal light modulation device 400G, and liquid crystal light modulation device 400B to form a color image. The cross dichroic prism 500 has a substantially square shape in plan view in which four right-angle prisms are bonded together, and a dielectric multilayer film is formed on a substantially X-shaped interface in which 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 diagram showing the light source device 10, and is a cross-sectional perspective view taken along the line IV-IV in FIG. 4 is a view showing the light source device 10 and is a cross-sectional view taken along the line IV-IV in FIG. FIG. 5 is a view showing the light source device 10 and is a partially enlarged view of FIG. In FIG. 5, 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. A joining portion 80, a translucent member 112, and a plurality of prisms 113.

  The base substrate 11 has a plate shape 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. The second surface 11b is a surface shown on the lower side in FIGS. In the state where the base substrate 11 is bonded to the bonding frame 107 and the bonding portion 80 as shown in FIGS. 2 to 4, the first surface 11a and the second surface 11b are planar. The base substrate 11 has, for example, a rectangular plate shape.

  In the XYZ orthogonal coordinate system shown in each drawing as appropriate, 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 orthogonal to the Z-axis direction and 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 short direction of the base substrate 11.

  In the following description, unless otherwise specified, the direction parallel to the thickness direction (Z-axis direction) of the base substrate 11 may be simply referred to as “thickness direction”, and the longitudinal direction (X-axis direction) of the base substrate 11 may be referred to. A direction parallel to the base plate 11 may be simply referred to as a “longitudinal direction”, and a direction parallel to the short side direction (Y-axis direction) of the base substrate 11 may be simply referred to as a “short side direction”.

  The base substrate 11 is formed with a through hole 11c that penetrates the base substrate 11 in the thickness direction (Z-axis direction). As shown in FIG. 2, the through holes 11 c are formed at the four corners of the base substrate 11. The through hole 11c has a circular shape in plan view. For example, a screw for fixing 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 high thermal conductivity such as copper in order to efficiently discharge the heat of the semiconductor laser element 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 the present 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 elements 110 are arranged so that five columns in which the five semiconductor laser elements 110 are arranged along the short direction (Y-axis direction) are arranged along the long direction (X-axis direction). Has been. In the following description, each column in which five semiconductor laser elements 110 are arranged along the short direction is referred to as light emitting element columns M1 to M5 (see FIG. 3). Moreover, when not distinguishing each light emitting element row | line | column M1-M5, the light emitting element row | line | columns M1-M5 are named generically and are only called the light emitting element row | line | column M.

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

  As shown in FIG. 5, the semiconductor laser element 110 emits laser light L in a first direction along the first surface 11a. In the present embodiment, the first direction is the longitudinal direction (X-axis direction). The semiconductor laser element 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 plan view. The material of the submount 103 is mainly ceramic 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). For example, the light emission surface 102 a from which the laser light L is emitted from the laser light source 102 substantially coincides with the side surface 103 a on one side in the longitudinal direction of the submount 103.

  The laser light L emitted from the laser light source 102 is emitted with a predetermined spread. In other words, 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) shape 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, that 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 a direction inclined within a predetermined angle range with respect to the first surface in addition to a direction parallel to the first surface. As an example, the first direction along the first surface includes a direction tilted within a range of ± 15 ° with respect to the first surface.

  As shown in FIG. 4, the joining frame 107 is joined to the first surface 11a. More specifically, the joining frame 107 is joined to the first surface 11 a via the joining portion 80. As shown in FIG. 2, the bonding frame 107 has a frame shape surrounding the plurality of semiconductor laser elements 110. In the present embodiment, the joining 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 short direction (Y axis direction). An electrode portion 109A is provided on the side wall 107a on one side (+ Y side), and an electrode portion 109B is provided on the side wall 107a on the other side (−Y side). The electrode portion 109A and the electrode portion 109B are provided in pairs for each of the light emitting element arrays 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 joining frame 107 is, for example, ceramics or kovar.

  As shown in FIG. 4, the bonding portion 80 bonds the base substrate 11 and the bonding frame 107. In the present embodiment, the bonding portion 80 is interposed between the base substrate 11 and the bonding frame 107. The joining portion 80 is a portion formed when joining the base substrate 11 and the joining frame 107 by brazing, for example. The brazing material constituting the joint 80 is preferably an inorganic material such as a metal material. This is because outgas is unlikely to occur during bonding, and it is possible to suppress the deterioration of the semiconductor laser element 110 due to the adhesion of outgas. In the present embodiment, the brazing material constituting the joint 80 is, for example, silver brazing. In addition, the joining method of 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 bonding frame 107. The translucent member 112 is fixed to the upper surface 107 c of the joining frame 107 on the side opposite to the base substrate 11 (+ Z side). The material for fixing the bonding frame 107 and the base substrate 11 is preferably an inorganic material such as a metal material, like the bonding portion 80. This is because outgas is unlikely to occur during bonding, and it is possible to suppress the deterioration of the semiconductor laser element 110 due to the adhesion of outgas. In the present embodiment, the translucent member 112 is bonded to the bonding frame 107 using, for example, low melting point glass.

  The translucent member 112 closes an opening on one side (+ Z side) of the joining frame 107. As a result, the base substrate 11, the bonding frame 107, and the translucent member 112 accommodate a plurality of semiconductor laser elements 110 and provide a sealed accommodation space K. The storage space K is filled with, for example, an inert gas or dry air. The storage space K may be in a reduced pressure state. The reduced pressure state refers to a state of a space filled with a gas having a pressure lower than the normal atmospheric pressure. In this definition, the gas may be an inert gas or dry air. By sealing the storage space K in this way, it is possible to suppress 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 joining 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 joining frame 107. When the intermediate member is used, the translucent member 112 and the intermediate member are bonded by, for example, low melting glass, and the bonding frame 107 and the intermediate member are bonded by, for example, low melting 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 arrays M1 to M5 provided on the base substrate 11, and is emitted from a plurality of semiconductor laser elements 110 constituting the corresponding light emitting element array M. 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) shape orthogonal to the extending direction of the prism 113 is, for example, a triangular shape.

  The prism 113 is disposed 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 beam L emitted from the semiconductor laser element 110 is incident, the reflecting surface 113b that reflects at least part of the laser beam L incident from the incident surface 113a, and the reflecting surface 113b. The laser beam L has an exit surface 113c from which the prism 113 exits.

  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 orthogonal to the longitudinal direction (X-axis direction). As shown in FIG. 4, the end of the incident surface 113 a on the opposite side (+ Z side) to the first surface 11 a is connected to the lower surface 112 a 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 113 b is a surface on the opposite side (−X side) of the semiconductor laser element 110 in the prism 113. 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 on the side (−X side) away from the semiconductor laser element 110 in the longitudinal direction (X-axis direction) as it goes to 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 reflecting surface 113 b opposite to the first surface 11 a (+ Z side) is connected to the lower surface 112 a of the translucent member 112.

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

  FIG. 6 is a graph showing the light intensity distribution of the laser light L emitted from the semiconductor laser element 110. In FIG. 6, the vertical axis indicates the light intensity of the laser light L, and the horizontal axis indicates the radial position about the center position C of the irradiation area IA1. 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 light intensity distribution of the laser light L is a Gaussian distribution as shown in FIG. An area irradiated with a portion of the laser light L where the light intensity is 1 / e ² of the maximum light intensity is referred to as an irradiation area IA1 of the laser light L. The irradiation area IA1 is an irradiation area of the laser beam L on the incident surface 113a as shown in FIG. 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, among the laser light L passing through the irradiation area IA1, the laser light Ld passing through the end of the irradiation area IA1 on the first surface 11a side (−Z side) and the first surface 11a of the irradiation area IA1. And a laser beam Lu passing through the end on the opposite side (+ Z side) and a laser beam Lc passing through the center position C of the irradiation area IA1. The laser beams Ld and Lu are laser beams whose light intensity is 1 / e ^{2 of the} center intensity. The laser beam Lc is a laser beam that overlaps with the optical axis LX and has a maximum light intensity, that is, a maximum.

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

  FIG. 7 is a diagram for explaining conditions under which the laser beam L incident on the reflecting surface 113b is totally reflected. As indicated by a dashed line arrow in FIG. 7, when the incident angle θ3 with respect to the reflecting surface 113b is smaller than a predetermined value, the laser light L is not totally reflected by the reflecting surface 113b but from the reflecting surface 113b at a refraction angle θ4. The light is emitted outside the prism 113. On the other hand, as indicated by a solid arrow in FIG. 7, when the incident angle θ3 is equal to or greater than a 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 indicates the incident angle θ3, and the vertical axis indicates 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 in the storage space K.

As shown in FIG. 8, when the incident angle θ3 is about 36 °, the refraction angle θ4 is 90 °. Thus, 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 reflecting surface 113b so that the incident angle θ3 of the laser light Ld with respect to the reflecting surface 113b is about 36 ° or more. It was found that the laser beam L can be totally reflected by the reflecting surface 113b. As described above, the condition of the incident angle θ3 of the laser beam Ld is obtained according to the refractive index of the prism 113 and the atmosphere outside the prism 113, that is, the refractive index of the atmosphere in the storage space K.

  When the reflective surface 113b is arranged based on the conditions of FIG. 8, as an example, the inclination angle θR (see FIG. 5) of the reflective surface 113b with respect to the incident surface 113a is set to 45 °. At this time, the radiation angle θ1 of the laser beam Ld is set to 8.5 °. The laser beam Ld incident on 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 °. For this reason, the total reflection condition shown in FIG. 8 is satisfied, and the laser beam Ld is totally reflected by the reflection surface 113b.

  As shown in FIG. 5, since the laser beams Lc and Lu enter the reflecting surface 113b at an incident angle θ3 larger than the laser beam Ld, when the laser beam Ld is totally reflected by the reflecting surface 113b, the laser beam Lc and Lu are also totally reflected by the reflecting surface 113b. In the present embodiment, the laser beam Lc overlapping the optical axis LX is designed to enter the reflecting surface 113b at an incident angle θ3 of 45 °. Therefore, the laser beam Lc is reflected by being bent by 90 ° on 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 beam L reflected by the reflecting surface 113b is emitted from the prism 113 through the emitting surface 113c.

The reflection surface 113b may totally reflect the laser light whose light intensity is smaller than 1 / e ^{2 of the} center intensity, or may not be totally reflected.

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

  In FIG. 5, the illustration of the translucent member 112 is omitted, and the laser light Ld and Lu are shown to be refracted and emitted to the outside on the emission surface 113 c. The laser beam L is incident on the light transmissive member 112 from the exit surface 113c, and the laser beams Ld and Lu are refracted on the upper surface 112b opposite to the prism 113 of the light transmissive member 112 (+ Z side). And emitted outside the light source device 10.

According to the present embodiment, the prism 113 has the reflecting 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. Therefore, it is possible to easily reflect a plurality of laser beams having different radiation angles θ1 only by designing the inclination angle θR of the reflecting surface 113b. Further, the total reflection condition by the reflection surface 113b does not substantially change depending on the wavelength of the laser light L, and the reflectance of the reflection surface 113b is lowered even when the wavelength of the laser light L is changed from a predetermined wavelength. Can be suppressed. Thereby, the light which is not reflected among the laser beams L emitted from the semiconductor laser element 110 can be reduced, and the light use efficiency of the light source device 10 can be suppressed from decreasing.

  In addition, when a plurality of semiconductor laser elements 110 are arranged as in the present embodiment, the wavelength variation of the laser light L emitted from each semiconductor laser element 110 tends to be large, and the laser light emitted from each semiconductor laser element 110 is emitted. It is more difficult to form a dielectric multilayer film corresponding to variations in the wavelength of the laser beam L. On the other hand, according to the present embodiment, the laser light L can be totally reflected without depending on the wavelength of the laser light L. That is, the effect of the present embodiment is particularly significant in a light source device in which a plurality of semiconductor laser elements 110 are arranged like the light source device 10 of the present embodiment.

  Note that 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 differs from the first embodiment in that an optical member 713 is provided. In addition, about the structure similar to the said embodiment, description may be abbreviate | omitted by attaching | subjecting the same code | symbol suitably.

  FIG. 9 is a cross-sectional view showing a portion of the light source device 1010 of the present 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 disposed on the opposite side (+ Z side) of the base substrate 11 of the prism 113. Although not shown, the optical member 713 is, for example, a prismatic member extending in the short direction (Y-axis direction). The cross section (ZX cross section) shape 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 disposed in the storage space K or may be disposed outside the storage space K. When the optical member 713 is disposed 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 apart from the translucent member 112. When the optical member 713 is disposed 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 incident 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 a surface on the opposite side (+ Z side) of the prism 113 of the optical member 713. 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 a side (+ Z side) that is further away from the first surface 11a in the thickness direction (Z-axis direction) toward the side (+ X side) closer to the semiconductor laser element 110 in the longitudinal direction (X-axis direction). ). The end of the second emission surface 713b opposite to the semiconductor laser element 110 in the longitudinal direction (−X side) is connected to the end of the second incident surface 713a opposite to 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 exit surface 113c of the prism 113 enters the optical member 713 from the second entrance surface 713a. The laser light L incident on the optical member 713 is refracted by 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 a 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 in a direction perpendicular to the first surface 11a by the optical member 713.

  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 whose light intensity is 1 / e ² or more of the central intensity, the refractive index of the prism 113 and the radiation angle θ1 of the laser light L are In some cases, the traveling direction of the laser light L emitted from the emission surface 113c cannot be set to 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 present embodiment, the desired direction is, for example, a direction perpendicular to the first surface 11a.

  On the other hand, according to this embodiment, the traveling direction of the laser light L emitted from the prism 113 can be changed by the optical member 713, and therefore the traveling direction of the laser light L emitted from the emission surface 113c. Even when the desired direction cannot be set, the traveling direction of the laser light L emitted from the light source device 1010 can be set to the desired direction. Therefore, according to the present 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 the traveling direction of the laser light L emitted from the prism 113 can be changed. The optical member 713 may be a reflecting plate or a lens, for example.

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

  FIG. 10 is a cross-sectional view showing a portion of the light source device 2010 of the present 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 element 810 is the same as the semiconductor laser element 110 described in the first embodiment. The second semiconductor laser element 910 is the same as the semiconductor laser element 110 described in the first embodiment, except that the second semiconductor laser element 910 is disposed so as to be reversed in the longitudinal direction (X-axis direction).

  The first semiconductor laser element 810 and the second semiconductor laser element 910 emit laser light L in opposite directions. In the present embodiment, the first semiconductor laser element 810 and the second semiconductor laser element 910 emit laser light L in a direction facing each other. The first semiconductor laser element 810 emits laser light L toward one side (−X side) in the longitudinal direction (X-axis direction), similarly to the semiconductor laser element 110 of the first embodiment. The second semiconductor laser element 910 emits 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 the same as the prism 113 described in the first embodiment. The second prism 913 is the same as the prism 113 described in the first embodiment, except that the second prism 913 is arranged so as to be reversed 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. Laser light L emitted from the second semiconductor laser element 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 are opposite to each other. 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 beam L incident on the first prism 813 is totally reflected by the reflecting surface 813b as in the first embodiment. The laser beam L incident on 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 for explaining a case where a reflection film and an antireflection film are formed on the prism of this 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 (the direction of the arrow in the drawing) of the reflecting surface 913b of the second prism 913. At least part of the incident surface 813a of the first prism 813 can be visually recognized. In the present embodiment, the entire incident surface 813a of the first prism 813 is visible.

  Note that in this specification, the fact that at least a part of the incident surface of the first prism can be visually recognized means that the incident surface can be visually recognized directly, and that an antireflection film or the like is formed on the incident surface. The case where the incident surface can be visually recognized, that is, the case where the antireflection film or the like is directly visible is included.

  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 the reflective film 881 is formed on each reflective surface, for example, a substance constituting the reflective film 881 is deposited on each reflective surface along the normal direction of each reflective surface. The arrow in FIG. 11 indicates the normal direction of the reflective surface 913b of the second prism 913, and indicates the vapor deposition direction when the reflective film 881 is formed on the reflective surface 913b. A uniform reflective film can be easily formed by depositing a material constituting the reflective film 881 on each reflective surface along the normal direction of each reflective surface.

  Here, as in this embodiment, when the reflecting surface of a certain prism is viewed along the normal direction, the incident surface of another prism is visible, and the reflecting film 881 is formed on the reflecting surface of a certain prism. When vapor deposition is performed, it is necessary to mask the incident surface of another prism. Specifically, as shown in FIG. 11, when the reflective film 881 is formed on the reflective surface 913b of the second prism 913, the first visible when the reflective 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 incident surface of another prism is visible when the reflecting surface of a certain prism is viewed along the normal direction, when the laser beam L is reflected by the reflecting film 881, In the formation of the reflective film 881, there is a problem in that it takes time and effort to perform masking, which increases the labor and cost of manufacturing the light source device.

  On the other hand, according to this 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 reflective film 881. Can be reflected. Therefore, it is possible to reduce the time and labor for forming the reflective film 881, and to suppress the labor and cost for manufacturing the light source device 2010.

  Further, as in this embodiment, the first semiconductor laser element 810 and the second semiconductor laser element 910 emit laser light L in opposite directions, and the reflecting 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 laser light L in opposite directions, and each reflection of each prism is reflected. This is particularly large when the surfaces 813b and 913b face each other.

  Note that the light source device 2010 of the present embodiment may be configured to include only one each of the first semiconductor laser element 810 and the second semiconductor laser element 910 as the plurality of semiconductor laser elements. The plurality of semiconductor laser elements may include at least a 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 present, the first prism 813 and the second prism 913 may be arranged such that each incident surface and each reflection surface face the same direction. In this case, the first semiconductor laser element 810 and the second semiconductor laser element 910 may emit laser light L in the same direction. 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 a laser beam L toward the other side (+ X side) of the longitudinal direction (X-axis direction), and the second semiconductor laser element 910 has a longitudinal direction (X-axis direction). ) 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 each other on the opposite side. 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 disposed 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. Even in this case, the reflective surface and the incident 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 reflective film 881 described above is particularly great.

  In each of the above embodiments, each incident surface may not be provided with an antireflection film, and each reflection surface may be provided with a reflection film.

  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 joining frame 107 and the translucent member 112 may not be provided.

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

  In each of the above embodiments, the projector 1000 including the three liquid crystal light modulation devices 400R, 400G, and 400B is illustrated. However, a projector that displays a color image with one liquid crystal light modulation device, and four or more liquid crystal lights. The present invention can also be applied to a projector that displays a color image with a modulation device. Further, a digital mirror device (DMD) may be used as the light modulation device.

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

  Moreover, each structure demonstrated above can be suitably combined in the range which is not mutually contradictory.

  DESCRIPTION OF SYMBOLS 10,1010,2010 ... Light source device, 11 ... Base substrate, 11a ... 1st surface, 30 ... Wavelength conversion element, 107 ... Joining frame, 112 ... Translucent member, 110 ... Semiconductor laser element, 113 ... Prism, 113a , 813a, 913a ... incidence surface, 113b, 813b, 913b ... reflection surface, 400B, 400G, 400R ... liquid crystal light modulation device (light modulation device), 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 (7)

A base substrate having a first surface;
A semiconductor laser element disposed on the first surface and emitting laser light in a first direction along the first surface;
A prism having an incident surface on which laser light emitted from the semiconductor laser element is incident, and a reflecting surface that reflects at least part of the laser light incident from the incident surface;
With
The reflection surface totally reflects a laser beam whose light intensity is 1 / e ² or more of the central intensity among the laser beams incident on the prism from the incident surface, where e is the base of the natural logarithm. A light source device characterized by being arranged.   The light source device according to claim 1, further comprising an optical member that changes a traveling direction of laser light emitted from the prism after being totally reflected by the reflection surface. A plurality of the semiconductor laser elements;
A frame-shaped bonding frame bonded to the first surface and surrounding the semiconductor laser element;
A translucent member facing the semiconductor laser element and fixed to the joining frame;
The light source device according to claim 1, further comprising: The semiconductor laser element includes a first semiconductor laser element and a second semiconductor laser element,
The prism includes a first prism on which a laser beam emitted from the first semiconductor laser element is incident, a second prism on which a laser beam 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 element and the second semiconductor laser element emit laser beams in opposite directions,
The entrance surface of the first prism and the entrance surface of the second prism face each other, or the reflection surface of the first prism and the reflection surface of the second prism face each other. The light source device according to claim 3.   The light source device according to claim 3 or 4, wherein the semiconductor laser element is accommodated and a sealed accommodation space is provided by the base substrate, the bonding frame, and the translucent member. A light source device according to any one of claims 1 to 5,
A light modulation device that modulates light emitted from the light source device;
A projection optical system for projecting light modulated by the light modulation device;
A projector comprising:   The projector according to claim 6, 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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