Light source device and display device

Abstract

To provide a light source device capable of reducing a speckle in a small size.SOLUTION: A light source device comprises: a substrate; a laser element that is arranged onto a main surface of the substrate, and emits a laser beam; an optical element that is arranged onto the main surface of the substrate, and an optical path of the laser beam; and a polarization element that is arranged onto the optical element. The optical element includes a first surface that reflects a first component of the lase beam entering from the laser element upward and a second surface that reflects a second component of the laser beam passing through the first surface upward from the laser beam entering from the laser element, and injects the first component of the laser beam that does not pass the polarization element and the second component of the laser beam passing through the polarization element.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a light source device and a display device. [Background technology]

[0002] Conventionally, a light source device that emits laser light and a display device such as a projector that includes the light source device are known. For example, Patent Document 1 discloses a configuration in which light from a semiconductor laser element is emitted through a microprism in order to miniaturize the semiconductor laser device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2001-244542 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a light source device that emits laser light, it is necessary to reduce speckle. One method for reducing speckle is to use laser light with different polarization states.

[0005] An object of an embodiment of the present disclosure is to provide a light source device that is small and capable of emitting laser light with different polarization states. [Means for solving the problem]

[0006] A light source device according to one embodiment of the present disclosure includes a substrate, a laser element disposed on a main surface of the substrate and emitting laser light, an optical element disposed on the main surface of the substrate and in an optical path of the laser light, and a polarizing element disposed on the optical element, the optical element having a first surface that reflects upward a first component of the laser light incident from the laser element, and a second surface that reflects upward a second component of the laser light incident from the laser element that transmits through the first surface, and emits the first component of the laser light that does not transmit through the polarizing element and the second component of the laser light that transmits through the polarizing element. Effect of the Invention

[0007] According to an embodiment of the present disclosure, a light source device that is small in size and can emit laser light with different polarization states can be provided. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic top view showing a light source device according to a first embodiment. [Diagram 2] 2 is a schematic cross-sectional view showing a first example of a line II-II in FIG. [Diagram 3] 2 is a schematic cross-sectional view showing a second example of the line II-II in FIG. 1. [Figure 4] FIG. 11 is a schematic perspective view showing a light source device according to a second embodiment. [Diagram 5] FIG. 11 is a schematic perspective view showing a light source device according to a third embodiment. [Figure 6] 13 is a schematic diagram showing a first example of an optical multiplexer included in a light source device according to a third embodiment. FIG. [Figure 7] 13 is a schematic diagram showing a second example of an optical multiplexer included in the light source device according to the third embodiment. FIG. [Figure 8] FIG. 13 is a schematic diagram showing a configuration of a display device according to a fourth embodiment. [Figure 9] FIG. 13 is a schematic perspective view showing a display device according to a fifth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] A light source device and a display device according to an embodiment of the present disclosure will be described in detail with reference to the drawings. However, the following embodiments are merely illustrative of light source devices and display devices for embodying the technical ideas of the present disclosure, and are not limited to the following. Furthermore, unless otherwise specified, the dimensions, materials, shapes, and relative arrangements of the components described in the embodiments are merely illustrative examples, and are not intended to limit the scope of the present disclosure to those alone. Note that the size, positional relationship, etc. of the components shown in each drawing may be exaggerated to clarify the explanation. In addition, in the following explanation, the same names and symbols indicate the same or similar components, and detailed explanations will be omitted as appropriate. An end view showing only a cut surface may be used as a cross-sectional view.

[0010] In each drawing, a Cartesian coordinate system with an X-axis, a Y-axis, and a Z-axis is used to represent directions. The X-axis, the Y-axis, and the Z-axis are mutually perpendicular. The side toward which the arrow points in the X direction along the X-axis is indicated as the +X side, and the side opposite the +X side is indicated as the -X side. The side toward which the arrow points in the Y direction along the Y-axis is indicated as the +Y side, and the side opposite the +Y side is indicated as the -Y side. The side toward which the arrow points in the Z direction along the Z-axis is indicated as the +Z side, and the side opposite the +Z side is indicated as the -Z side.

[0011] The +Z side is called "up" and the -Z side is called "down". Planar view means viewing a target surface from the normal direction of the target surface. A plan view of an object means a view of the object in a planar view. However, the terms indicating these specific directions and positions are only used to make the relative directions and positions in the referenced drawings easier to understand. These directional expressions do not limit the orientation when the light source device and display device according to the embodiment are used, and the orientation when the light source device and display device according to the embodiment are used is arbitrary.

[0012] In the following embodiments, "along the X-axis, Y-axis, and Z-axis" includes the object having a tilt within a range of ±10 degrees with respect to these axes. In the embodiments, each of the perpendicular and orthogonal directions may have an error of ±10 degrees with respect to 90 degrees. Also, a rotation of 90 degrees may have an error of ±10 degrees.

[0013] In addition, in this specification or claims, when there are multiple elements of a certain type and each element is to be expressed with a distinction, the elements may be distinguished by adding "first," "second," etc. to the beginning of the element. In addition, the objects to be distinguished may differ between this specification and the claims. Therefore, even if the claims describe an element with the same notation as this specification, the object identified by this element may not match between this specification and the claims.

[0014] [First embodiment] A light source device according to a first embodiment will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is a schematic top view showing a light source device 100 according to the first embodiment. Fig. 2 is a schematic cross-sectional view showing a first example of the line II-II in Fig. 1.

[0015] <Example 1> The light source device 100 includes a substrate 1, a laser element 2 disposed on a main surface 10 of the substrate 1 and emitting laser light L, an optical element 3 disposed on the main surface 10 of the substrate 1 and in the optical path of the laser light L, and a polarizing element 4 disposed on the optical element 3. The optical element 3 includes a first surface 31 that reflects upward a first component L1 of the laser light L incident from the laser element 2, and a second surface 32 that reflects upward a second component L2 of the laser light L that is transmitted through the first surface 31, among the laser light L incident from the laser element 2. The light source device 100 emits the first component L1 of the laser light L that is not transmitted through the polarizing element 4, and the second component L2 of the laser light L that is transmitted through the polarizing element 4.

[0016] In the example shown in FIG. 1 and FIG. 2, the laser element 2 emits the laser light L to the +Y side. The first surface 31 of the optical element 3 reflects the first component L1 of the laser light L upward (to the +Z side). The light source device 100 emits the first component L1, which is reflected by the first surface 31 and does not pass through the polarizing element 4, upward. On the other hand, the second surface 32 of the optical element 3 reflects the second component L2 of the laser light L, which passes through the first surface 31, upward. The second component L2 reflected by the second surface 32 passes through the polarizing element 4. The light source device 100 emits the second component L2, which is reflected by the second surface 32 and passes through the polarizing element 4, upward and has a different polarization state from the polarization state of the first component L1. In this way, the light source device 100 can emit the first component L1 and the second component L2, which have different polarization states from each other, upward.

[0017] When the polarization state of some of the laser beams is different from the polarization state of other beams, these laser beams are combined to reduce interference compared to when the polarization states of all the laser beams are uniform. This reduces speckles caused by interference between scattered beams of the laser. For example, when some of the laser beams are S-polarized and other beams are P-polarized, and the amount of S-polarized and P-polarized light is almost equal, speckles are particularly reduced compared to when the polarization states of all the laser beams are uniform. For example, speckles are reduced by about 15% to 25% compared to when all the beams are S-polarized or P-polarized.

[0018] The light source device 100 emits the first component L1 and the second component L2, which have different polarization states. As a result, in the light source device 100, speckles are reduced compared to when all the polarization states of the laser light L are aligned by multiplexing these components. In addition, in the light source device 100, the first component L1 and the second component L2 have different optical path lengths, so speckles can also be reduced by time multiplexing. In addition, the light source device 100 emits the first component L1 and the second component L2, which have different polarization states, based on the first component L1 and the second component L2 branched using the optical element 3. Since the optical element 3 is a single structure, it can be made compact. Therefore, in the light source device 100, the use of the optical element 3 makes it possible to make the light source device 100 compact. As a result, in this embodiment, it is possible to provide a light source device 100 that is small and can reduce speckles.

[0019] For example, in the light source device 100, when the first component L1 is S-polarized light and the second component L2 is P-polarized light and the light amounts of the first component L1 and the second component L2 are substantially equal, speckles can be particularly reduced compared to the case where all the polarization states of the laser light L are uniform. However, the combination of the polarization states of the first component L1 and the second component L2 is not limited to the combination of P-polarized light and S-polarized light as long as the polarization states are different from each other. For example, the combination of the first component L1 and the second component L2 may be a combination of linearly polarized light that is not orthogonal to each other, a combination of linearly polarized light and circularly polarized light or elliptically polarized light, or a combination of elliptically polarized light whose major axis directions are different from each other.

[0020] In the example shown in FIG. 1 and FIG. 2, the smaller of the angles between the first surface 31 of the optical element 3 and the main surface 10 of the substrate 1 is the first angle α. The smaller of the angles between the second surface 32 of the optical element 3 and the main surface 10 of the substrate 1 is the second angle β, which is smaller than the first angle α. As described above, the optical element 3 is a single structure, so that it is easy to reduce the size. In this embodiment, the optical element 3 is used, and only the second component L2 extracted from the optical element 3 is transmitted through the polarizing element 4, so that a light source device 100 can be provided that is small and can emit the first component L1 and the second component L2, which have different polarization states, in approximately the same direction. Note that the refraction angle of the laser light L at the first surface 31 varies depending on the wavelength of the laser light L, so the second angle β may be appropriately changed depending on the wavelength of the laser light L.

[0021] 1 and 2, the light source device 100 further includes a lens 5 disposed between the laser element 2 and the optical element 3. For example, the lens 5 collimates the laser light L emitted from the laser element 2. This reduces the amount of laser light L emitted from the laser element 2 that leaks out without entering the optical element 3, thereby increasing the emission efficiency of the laser light from the light source device 100. Furthermore, the smaller spread of the laser light L emitted from the laser element 2 allows the optical element 3 to be made more compact.

[0022] In the example shown in FIG. 1 and FIG. 2, the light source device 100 is further provided with a support member 6 disposed on the main surface 10 of the substrate 1 and supporting the laser element 2 and the lens 5. The support member 6 includes a first region 61 in which the laser element 2 is disposed, and a second region 62 in which the lens 5 is disposed. In the normal direction (Z direction) of the main surface 10, a first height h1 of a first upper surface 610 of the first region 61 with respect to the main surface 10, and a second height h2 of a second upper surface 620 of the second region 62 with respect to the main surface 10 are adjusted so that a central axis L0 of the laser light L emitted from the laser element 2 and an optical axis 50 of the lens 5 are aligned. With this configuration, the laser light L from the laser element 2 can be efficiently extracted through the lens 5, and therefore the emission efficiency of the laser light from the light source device 100 can be increased. Here, the alignment of the central axis L0 of the laser light L with the optical axis 50 of the lens 5 also includes a case where the deviation between them is within a range of ±50 μm in the Z direction. In FIG. 2, the central axis L0 of the laser light L and the optical axis 50 of the lens 5 overlap, so both symbols are shown.

[0023] (Substrate 1) The substrate 1 is a plate-like member having a substantially rectangular shape when viewed from above. Various elements can be arranged on the main surface 10 of the substrate 1. The substrate 1 is made of a material including a resin material, a metal material, or the like. From the viewpoint of increasing the efficiency of dissipating heat generated by the laser element 2, it is preferable that the substrate 1 is made of a material having high thermal conductivity. For example, the material of the substrate 1 can be copper, aluminum, graphene, aluminum nitride, silicon, or the like.

[0024] (Laser element 2) The laser element 2 is disposed on the main surface 10 of the substrate 1. Even if a support member 6 described later is disposed between the laser element 2 and the substrate 1, the laser element 2 is considered to be disposed on the main surface 10 of the substrate 1. For example, a semiconductor laser element that emits laser light having an oscillation peak wavelength in the range of 420 nm to 495 nm can be used as the laser element 2. However, the laser element 2 may be one that emits laser light L having an oscillation peak wavelength in the visible light range of 380 nm to 780 nm, or one that emits laser light L in the invisible light range such as infrared light or ultraviolet light. In the example shown in FIG. 1 and FIG. 2, the laser element 2 emits linearly polarized laser light L that spreads toward the lens 5.

[0025] The laser element 2 is preferably made of a material including, for example, a nitride semiconductor. Examples of nitride semiconductors include at least one of GaN, InGaN, and AlGaN. The laser element 2 may also be made of a material such as GaAs, AlGaInP, InGaAsP, or AlGaAs. The laser element 2 is fixed to the first upper surface 610 of the first region 61 of the support member 6 using an adhesive member, a screw member, or the like.

[0026] The laser device 2 may be an edge-emitting laser device, a vertical cavity surface-emitting laser device, or a photonic crystal surface-emitting laser device.

[0027] (Optical element 3) The optical element 3 is composed of glass, crystal, or the like having translucency to the laser light L emitted from the laser element 2. The optical element 3 is, for example, a prism. The translucency of the optical element 3 is preferably such that the transmittance to the laser light L emitted from the laser element 2 is 60% or more. The optical element 3 is disposed such that the lower surface 34 of the optical element 3 faces the main surface 10 of the substrate 1, and is fixed to the main surface 10 of the substrate 1 by a joining member (for example, AuSn), solder, an adhesive member, or the like. From the viewpoint of increasing heat dissipation efficiency, it is preferable that a metal film is provided on the lower surface 34 of the optical element 3, i.e., the surface facing the substrate 1 when fixed to the substrate 1.

[0028] In the example shown in FIG. 1 and FIG. 2, the first surface 31 of the optical element 3 is a mirror having a predetermined reflectance, and the second surface 32 of the optical element 3 is either a total reflection mirror or a dichroic mirror. With this configuration, the reflectance of the first surface 31 can be adjusted in advance to adjust the light amounts of the first component L1 and the second component L2 having different polarization states. For example, the transmittance of the laser light L at the first surface 31 is greater than the reflectance. This allows the light amounts of the first component and the second component to be adjusted taking into account the loss caused by the laser light propagating inside the optical element 3 and the loss at the second surface. The first surface 31 may be provided with, for example, a dielectric multilayer film. For example, the transmittance of the first surface 31 at the wavelength of the laser light may be 50% or more and 60% or less, and the reflectance may be 40% or more and less than 50%.

[0029] In the example shown in FIG. 1 and FIG. 2, the second surface 32 of the optical element 3 includes a metal film or a dielectric multilayer film. This configuration can improve the reflectance of the second component L2 by the second surface 32. When the transmittance of the laser light at the first surface is greater than the reflectance, the light amounts of the first component L1 and the second component L2, which have different polarization states, can be made closer. The second surface 32 of the optical element 3 preferably includes a dielectric multilayer film. The reflectance is improved and the absorptance is reduced for the wavelength of the laser light. The reflectance of the second surface 32 at the wavelength of the laser light may be, for example, 80% or more, 90% or more, or 95% or more. The reflectance of the second surface 32 is less than 100%.

[0030] (Polarizing element 4) The polarizing element 4 changes the polarization state of the incident light. The polarizing element 4 is configured to include a crystal having translucency to the laser light L emitted from the laser element 2. The polarizing element 4 may be made of, for example, quartz crystal or mica. The translucency of the polarizing element 4 preferably has a transmittance of 90% or more, 95% or more, or 98% or more to the laser light L emitted from the laser element 2. The polarizing element 4 is disposed on the upper surface 33 of the optical element 3, and is fixed to the upper surface 33 by an adhesive member or the like.

[0031] 1 and 2, the polarizing element 4 is a half-wave plate. The polarizing element 4 is arranged such that the optical axis of the polarizing element 4 is tilted at approximately 45 degrees with respect to the polarization direction of the laser light L, which is linearly polarized light. As a result, the polarizing element 4 can rotate the polarization direction of the second component L2 incident on the polarizing element 4 by 90 degrees with respect to the polarization direction of the first component L1, and make the polarization direction of the first component L1 and the polarization direction of the second component L2 orthogonal to each other. The light source device 100 can emit, for example, the first component L1, which is S-polarized light, and the second component L2, which is P-polarized light.

[0032] By using a half-wave plate for the polarizing element 4, the polarization direction of the polarized light incident on the polarizing element 4 can be changed. As a result, the light source device 100 can increase the emission efficiency of the first component L1 and the second component L2, which are linearly polarized light with different polarization directions. In addition, the light source device 100 can preferably reduce speckles by using the polarizing element 4 to rotate the polarization direction of the second component L2 by 90 degrees with respect to the polarization direction of the first component L1. However, the inclination angle of the optical axis of the polarizing element 4 with respect to the polarization direction of the laser light L is not limited to 45 degrees and can be changed as appropriate. In addition, the polarizing element 4 is not limited to a half-wave plate as long as it can change the polarization state of the incident light. The polarizing element 4 may be a quarter-wave plate.

[0033] (Lens 5) The lens 5 may be a plano-convex single lens, a biconvex single lens, a meniscus single lens, a Fresnel lens, a diffractive lens, a lens set consisting of a plurality of single lenses, or the like, which are configured to include a glass material or crystal having translucency to the laser light L emitted from the laser element 2. The lens 5 may be made of, for example, synthetic quartz. The translucency of the lens 5 is preferably such that the transmittance to the laser light L emitted from the laser element 2 is 90% or more, 95% or more, or 98% or more. The lens 5 may include at least one of a spherical lens and an aspherical lens. The type, arrangement, shape, and the like of the lens 5 may be appropriately changed according to the specifications of the light source device 100, and the like. The lens 5 is fixed to the second upper surface 620 of the second region 62 of the support member 6 by an adhesive member or the like.

[0034] When the lens 5 is provided, the laser element 2 is preferably an edge-emitting laser element or a vertical cavity surface-emitting laser element, more preferably an edge-emitting laser element, and the collimation effect of the lens 5 is greater than that of other laser elements.

[0035] (Support member 6) The support member 6 is made of a material containing a ceramic material, a metal material, or the like. From the viewpoint of increasing the efficiency of dissipating heat generated by the laser element 2, it is preferable that the support member 6 is made of a material having high thermal conductivity. For example, the material of the support member 6 may be copper, aluminum, graphene, aluminum nitride, silicon, or the like. The support member 6 is disposed so that the lower surface of the support member 6 faces the main surface 10 of the substrate 1, and is fixed to the substrate 1 by an adhesive member or the like. Note that the support member 6 and the substrate 1 may be separate bodies and made of different materials, or may be separate bodies and made of the same material, or may be integrated.

[0036] <Second Example> Fig. 3 is a schematic cross-sectional view showing a second example taken along line II-II in Fig. 1. The second example differs from the first example in that the light source device 100 includes a support member 7 for optical elements.

[0037] The optical element support member 7 is made of glass, a metal material, or the like. The optical element support member 7 is arranged so as to fill a gap between the principal surface 10 and a second surface 32 of the optical element 3 arranged on the principal surface 10 of the substrate 1. By including the optical element support member 7, the light source device 100 can stably arrange the optical element 3 on the principal surface 10 of the substrate 1 so as not to move.

[0038] [Second embodiment] Next, a light source device according to a second embodiment will be described. Note that the same names and symbols as those in the already described embodiments indicate the same or similar members or configurations, and detailed descriptions will be omitted as appropriate. This also applies to the following embodiments.

[0039] 4 is a schematic perspective view showing a light source device 100a according to the second embodiment. The light source device 100a differs from the first embodiment in that it includes a plurality of laser elements 2a, a plurality of optical elements 3a, a plurality of polarizing elements 4a, a plurality of lenses 5a, and a plurality of support members 6a. The light source device 100a also differs from the first embodiment in that it includes a housing member 8 that houses the laser element 2a and the optical element 3a, and a lid portion 9 that seals the housing member 8.

[0040] The multiple laser elements 2a include laser element 2R, laser element 2G, and laser element 2B. Laser element 2R emits red laser light. The laser element 2R may be one that emits laser light having an oscillation peak wavelength in the range of 605 nm to 750 nm. Laser element 2G emits green laser light. The laser element 2G may be one that emits laser light having an oscillation peak wavelength in the range of 495 nm to 570 nm. Laser element 2B emits blue laser light. The laser element 2B may be one that emits laser light having an oscillation peak wavelength in the range of 420 nm to 495 nm.

[0041] The optical elements 3a include an optical element 3R, an optical element 3G, and an optical element 3B. The optical element 3R is disposed on the main surface 10 of the substrate 1 and on the optical path of the red laser light from the laser element 2R. The optical element 3G is disposed on the main surface 10 of the substrate 1 and on the optical path of the green laser light from the laser element 2G. The optical element 3B is disposed on the main surface 10 of the substrate 1 and on the optical path of the blue laser light from the laser element 2B. The angle β between the second surface 32 of each of the optical elements 3R, 3G, and 3B and the main surface 10 of the substrate 1 is adjusted according to the wavelength of the light incident on each of the optical elements 3R, 3G, and 3B. For example, the angle β is an angle that reflects the second surface 32 in a direction perpendicular to the main surface 10 of the substrate 1, taking into account the wavelength of the light and the refractive index of the optical element.

[0042] The multiple polarizing elements 4a include a polarizing element 4R, a polarizing element 4G, and a polarizing element 4B. The polarizing element 4R is disposed on the optical element 3R. The polarizing element 4G is disposed on the optical element 3G. The polarizing element 4B is disposed on the optical element 3B.

[0043] The multiple lenses 5a include a lens 5R, a lens 5G, and a lens 5B. The lens 5R is disposed between the laser element 2R and the optical element 3R. The lens 5R transmits the red laser light emitted from the laser element 2R. The lens 5G is disposed between the laser element 2G and the optical element 3G. The lens 5G transmits the green laser light emitted from the laser element 2G. The lens 5B is disposed between the laser element 2B and the optical element 3B. The lens 5B transmits the blue laser light emitted from the laser element 2B.

[0044] The multiple support members 6a include support member 6R, support member 6G, and support member 6B. Support member 6R is disposed on main surface 10 of substrate 1 and supports laser element 2R. Support member 6G is disposed on main surface 10 of substrate 1 and supports laser element 2G. Support member 6B is disposed on main surface 10 of substrate 1 and supports laser element 2B. Although FIG. 4 illustrates a form in which different support members 6a are used for each laser element 2a, each laser element 2a may be supported by one support member 6a.

[0045] The housing member 8 is a box-shaped member that includes a recess 80 and is open above the recess 80. In the example shown in FIG. 4, the housing member 8 houses therein a substrate 1, a laser element 2a, and an optical element 3a. The laser element 2a and the optical element 3a may be disposed directly on the bottom surface of the housing member 8 without the substrate 1. In this case, the housing member 8 also has the function of the substrate 1.

[0046] The lid portion 9 is disposed so as to cover the upper side of the recess 80 in the housing member 8. The lid portion 9 can seal the housing member 8 by covering the upper side of the recess 80 in the housing member 8. Note that since the end face of the laser element 2a has a high light density and is prone to dust collection, the recess of the housing member 8 may be filled with gas. By filling the recess 80 with gas and covering the upper side of the recess with the lid portion 9, the laser element 2a can be sealed.

[0047] In the light source device 100a, by accommodating the laser element 2a and the optical element 3a in the accommodating member 8, contamination of the laser element 2a and the optical element 3a by dust, droplets, and the like can be reduced.

[0048] Although FIG. 4 illustrates a configuration having multiple laser elements, optical elements, polarizing elements, lenses, and support members, the above-described effects of the light source device 100a can be obtained even with a configuration having one each of the laser elements, optical elements, polarizing elements, lenses, and support members.

[0049] Effects of the light source device 100a other than those described above are similar to those of the first embodiment.

[0050] The optical element 3a and the polarizing element 4a are housed in a housing member 8. This allows the sizes of the optical element 3a and the polarizing element 4a to be reduced, since laser light with different polarization states can be obtained before the laser light spreads too much, compared to a case where the optical element and the polarizing element are disposed outside the package constituting the light source device. Therefore, for example, when constructing a display device, the size of the entire system can be reduced.

[0051] [Third embodiment] Next, a light source device according to a third embodiment will be described with reference to Fig. 5 and Fig. 6. Fig. 5 is a schematic perspective view showing a light source device 100b according to the third embodiment. Fig. 6 is a schematic view showing a first example of an optical multiplexer 11 included in the light source device 100b.

[0052] The light source device 100b differs from the second embodiment mainly in that an optical multiplexer 11 that multiplexes the first and second components of the laser light emitted from the laser element 2 is further provided.

[0053] In the example shown in FIG. 5, the light source device 100b includes a plurality of optical multiplexers 11. The plurality of optical multiplexers 11 include an optical multiplexer 11R, an optical multiplexer 11G, and an optical multiplexer 11B. The optical multiplexer 11R multiplexes the first and second components of the laser light emitted from the laser element 2R and incident on the optical multiplexer 11R via the lens 5R, the optical element 3R, and the polarizing element 4R. The optical multiplexer 11G multiplexes the first and second components of the laser light emitted from the laser element 2G and incident on the optical multiplexer 11G via the lens 5G, the optical element 3G, and the polarizing element 4G. The optical multiplexer 11B multiplexes the first and second components of the laser light emitted from the laser element 2B and incident on the optical multiplexer 11B via the lens 5B, the optical element 3B, and the polarizing element 4B.

[0054] In the light source device 100b, by multiplexing and emitting laser light having different polarization states using the optical multiplexer 11, it is possible to reduce the speckle in the laser light emitted from the light source device 100b compared to the case where laser light having a uniform polarization state is emitted.

[0055] 5, the optical multiplexer 11 is provided on the lid 9. For example, the optical multiplexer 11 is disposed on the upper surface (the surface on the +Z side) of the lid 9. For example, the optical multiplexer 11 can be fixed to the lid 9 using an adhesive. This eliminates the need to provide a separate member for supporting the optical multiplexer 11, and allows the light source device 100b to be made smaller.

[0056] In the example shown in FIG. 5, the light source device 100b is configured to have multiple optical multiplexers 11, but in the case where the light source device 100b has one each of a laser element, an optical element, a polarizing element, and a lens, the light source device 100b may be configured to have one optical multiplexer 11.

[0057] The optical multiplexer 11 may be a prism that reflects one of the first and second components two or more times and transmits the other of the first and second components to multiplex the first and second components. In the example shown in FIG. 6, the optical multiplexer 11 includes a first prism surface 111 and a second prism surface 112. The optical multiplexer 11 reflects the first component L1 at the first prism surface 111 and the second prism surface 112. The optical multiplexer 11 can also transmit the second component L2 at the second surface to multiplex the first component L1 and the second component L2. The prism may be made of glass, crystal, or the like that is translucent to the first component L1 and the second component L2. A dielectric multilayer film is provided on the first prism surface 111 and the second prism surface 112.

[0058] The optical multiplexer 11 is not limited to the prism shown in Fig. 6. Fig. 7 is a schematic diagram showing a second example of the optical multiplexer 11. In the example shown in Fig. 7, the optical multiplexer 11 is a beam expander including a concave lens 113 and a convex lens 114. The beam expander can combine the first component L1 and the second component L2 incident thereon by expanding the beam diameters of these components.

[0059] The concave lens 113 and the convex lens 114 can be configured to include glass or crystal having transparency to the first component L1 and the second component L2. However, the beam expander is not limited to a configuration including the concave lens 113 and the convex lens 114, and can be configured by combining various lenses, as long as the beam expander can combine the first component L1 and the second component L2 by expanding the beam diameters of the first component L1 and the second component L2.

[0060] Although FIG. 5 illustrates a configuration having multiple laser elements, optical elements, polarizing elements, lenses, and support members, the above-described effects of light source device 100b can also be obtained with a configuration having one each of laser elements, optical elements, polarizing elements, lenses, and support members.

[0061] In addition, in this embodiment, a display device including the light source device 100b can be configured. The display device is, for example, a projector. For example, the display device includes the light source device 100b, a spatial modulator that generates an image to be displayed by the display device, and a projection lens that projects the image generated by the spatial modulator. The image includes a still image and a moving image. This point is also true in the case where the term "image" is used hereinafter.

[0062] In this embodiment, the light source device 100b is provided, which is small and emits the first component L1 and the second component L2 having different polarization states, thereby making it possible to miniaturize the display device and reduce speckles caused by the laser light emitted from the display device. The light source device 100b may use a prism or a beam expander as the optical multiplexer 11, but it is preferable to use a prism. As described with reference to FIG. 5, the optical multiplexer 11 using a prism can be disposed on the upper surface of the lid portion 9 of the light source device 100b. At this time, the optical multiplexer 11 can be easily fixed with an adhesive, so no exterior parts are required to support the optical multiplexer. In addition, since the optical multiplexer 11 is disposed on the upper surface of the lid portion 9, the first component and the second component can be multiplexed while the beam diameter of the laser light is relatively small. Therefore, the optical system that multiplexes the first component and the second component becomes small, and the display device becomes small.

[0063] In the second and third embodiments, the laser elements 2a may include a plurality of laser elements that emit red, green, or blue laser light. That is, the laser elements 2a may include a plurality of laser elements that emit laser light of the same color. This provides a speckle reduction effect by the effect of wavelength multiplexing. At this time, the difference between the longest wavelength and the shortest wavelength within the range of the same color among the oscillation peak wavelengths of the laser light emitted from the plurality of laser elements 2a may be, for example, 5 nm to 40 nm, 5 nm to 30 nm, 5 nm to 20 nm, or 5 nm to 10 nm. However, it is not necessarily necessary to compare the longest wavelength laser light with the shortest wavelength laser light, and as long as the laser light includes a wavelength with a difference between the reference wavelength and the oscillation peak wavelength of the laser light of 20 nm or less, 15 nm or less, 10 nm or less, or 5 nm or less, the speckle reduction effect can be provided by the effect of wavelength multiplexing.

[0064] [Fourth embodiment] Next, a display device according to a fourth embodiment will be described with reference to Fig. 8. Fig. 8 is a schematic diagram showing the configuration of a display device 200 according to the fourth embodiment.

[0065] The display device 200 includes three or more light source devices according to the embodiment. The three or more light source devices emit at least red, blue, and green laser light. In the example shown in FIG. 8, the display device 200 includes a light source device 100R, a light source device 100G, a light source device 100B, a first lens 12, a dichroic prism 13, a second lens 14, a light diffusion plate 15, a third lens 16, and a light uniformizing optical system 17. The light uniformizing optical system 17 includes a first lens array 171, a second lens array 172, and a fourth lens 173.

[0066] Display device 200 may further include a spatial modulator that generates an image to be displayed by display device 200, and a projection lens that projects the image generated by the spatial modulator. Display device 200 may further include a multiplexing optical system that multiplexes different polarized lights emitted by light source device 100R, light source device 100G, and light source device 100B. Light source device 100R, light source device 100G, and light source device 100B may be arranged in an array in a predetermined direction.

[0067] The light source device 100R, the light source device 100G, and the light source device 100B correspond to the light source devices according to the third or more embodiments. The light source device 100R emits a red laser light LR. The light source device 100G emits a green laser light LG. The light source device 100B emits a blue laser light LB. Each of the light source device 100R, the light source device 100G, and the light source device 100B can have substantially the same configuration as the above-mentioned light source device 100b, except for the color of the emitted laser light. In this embodiment, the light source device 100R has a plurality of laser elements that emit a red laser light LR. The light source device 100G has a plurality of laser elements that emit a green laser light LG. The light source device 100B has a plurality of laser elements that emit a red laser light LB.

[0068] The first lens 12 transmits the laser light LG emitted by the light source device 100G. The dichroic prism 13 combines the laser light LR from the light source device 100R, the laser light LG from the first lens 12, and the laser light LB from the light source device 100B, and emits the combined light toward the second lens 14.

[0069] The second lens 14 transmits the laser lights LR, LG, and LB combined by the dichroic prism 13. The light diffusion plate 15 diffuses the laser lights LR, LG, and LB that have passed through the second lens 14. The laser lights LR, LG, and LB diffused by the light diffusion plate 15 pass through the third lens 16 and enter the light uniformization optical system 17. The laser lights LR, LG, and LB pass through the first lens array 171, the second lens array 172, and the fourth lens 173 in the light uniformization optical system 17, so that the illuminance of the laser lights LR, LG, and LB is substantially uniformed, and then the laser lights can be emitted from the light uniformization optical system 17. In addition, the beam diameters of the first component L1 and the second component L2 are different as shown in FIG. 2 and FIG. 3, but the beam diameters of the laser lights LR, LG, and LB including the first component L1 and the second component L2 can also be uniformed by passing through the light uniformization optical system 17.

[0070] The display device 200 can be made smaller by including the light source devices 100R, 100G, and 100B that are small and emit the first component L1 and the second component L2 that have different polarization states. In addition, the display device 200 can reduce speckles caused by the laser light emitted from the light source devices 100R, 100G, and 100B in the image displayed by the display device 200. The light source devices 100R, 100G, and 100B can further include an optical multiplexer 11 using a prism, so that the display device 200 can be made even smaller. In addition, the display device 200 can obtain a speckle reduction effect by wavelength multiplexing by emitting a plurality of laser lights having different oscillation peak wavelengths in the same color range from the light source device 100R. The same applies to the light source devices 100G and 100B.

[0071] In the display device 200, the effects of the light source devices 100R, 100G, and 100B other than those described above are similar to those of the first embodiment.

[0072] [Fifth embodiment] Next, a display device according to a fifth embodiment will be described with reference to Fig. 9. Fig. 9 is a schematic perspective view showing the configuration of a display device 200a according to the fifth embodiment.

[0073] The display device 200a includes a laser element driver 210, a light source device 100a, and an optical scanning mechanism 220. For example, the display device 200a may be a head-up display mounted on a moving object. The moving object includes vehicles such as automobiles and trains, aircraft, ships, and the like.

[0074] The laser element driver 210 drives the laser elements 2R, 2G, and 2B included in the light source device 100a by supplying drive signals to each of them.

[0075] The light source device 100a emits red, green, and blue laser light. The display device 200a may include a light source device 100b instead of the light source device 100a, or a plurality of light source devices 100 that emit laser light of different colors, for example, red, green, and blue laser light.

[0076] The optical scanning mechanism 220 scans the laser light from the light source device 100a on the display surface S. The display surface S is, for example, the front windshield of an automobile. For example, the optical scanning mechanism 220 is a MEMS (Micro Electro Mechanical Systems) mirror that can swing a movable part including a reflective surface around a predetermined swing axis. The optical scanning mechanism 220 scans the laser light incident from the light source device 100a and reflected by the reflective surface on the display surface S by swinging the movable part. In addition, the optical scanning mechanism 220 can scan the laser light in two axial directions that are approximately perpendicular to each other within a plane along the display surface S by swinging the movable part around two swing axes that are approximately perpendicular to each other. However, the optical scanning mechanism 220 is not limited to a MEMS mirror as long as it can scan the laser light from the light source device 100a. A galvanometer mirror, a polygon mirror, or the like may be used.

[0077] The display device 200a can display an image via the display surface S by scanning the laser light from the light source device 100a on the display surface S using the optical scanning mechanism 220. For example, as shown in Fig. 9, the display device 200a can display a virtual image of an image including information such as the traveling speed of an automobile equipped with the display device 200a, and can be visually recognized by the driver of the automobile. In addition, the display device 200a can display a two-dimensional image via the display surface S by scanning the laser light from the light source device 100a in two axial directions that are substantially perpendicular to each other within a plane along the display surface S using the optical scanning mechanism 220.

[0078] In this embodiment, the display device 200a can be made smaller by including a light source device 100a that is small and emits a first component L1 and a second component L2 that have different polarization states. In addition, speckles caused by the laser light emitted from the light source device 100a can be reduced in an image displayed by the display device 200a. The display device 200a may also include light source devices 100R, 100G, and 100B that emit red, green, and blue laser light. The light source devices 100R, 100G, and 100B emit laser light of different oscillation peak wavelengths in the same color range for each color, thereby obtaining a speckle reduction effect due to wavelength multiplexing.

[0079] In the display device 200a, the effects of the light source device 100a other than those described above are similar to those of the first embodiment.

[0080] The display device according to the fifth embodiment can be used not only for the above-mentioned applications but also for head-mounted displays.

[0081] Although the preferred embodiments have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the claims.

[0082] The ordinal numbers, quantities, and other numbers used in the description of the embodiments are all provided as examples to specifically explain the technology of the present disclosure, and the present disclosure is not limited to the illustrated numbers. Furthermore, the connection relationships between the components are provided as examples to specifically explain the technology of the present disclosure, and do not limit the connection relationships that realize the functions of the present disclosure.

[0083] INDUSTRIAL APPLICABILITY The light source device and display device of the present disclosure are small and capable of reducing speckle, and therefore can be suitably used in projectors that use laser light, head-mounted displays, rear projectors, head-up displays, and the like.

[0084] Aspects of the present disclosure are, for example, as follows. <Item 1> A light source device comprising: a substrate; a laser element disposed on a main surface of the substrate and emitting laser light; an optical element disposed on the main surface of the substrate and in an optical path of the laser light; and a polarizing element disposed on the optical element, wherein the optical element includes a first surface that reflects upward a first component of the laser light incident from the laser element, and a second surface that reflects upward a second component of the laser light incident from the laser element that transmits through the first surface, and emits the first component of the laser light that does not transmit through the polarizing element and the second component of the laser light that transmits through the polarizing element. <Item 2> The smaller of the angles between the first surface and the main surface of the substrate is a first angle α, and the smaller of the angles between the second surface and the main surface of the substrate is a second angle β smaller than the first angle α. <1> 2 is a light source device according to the first embodiment. <Item 3> The laser device further includes a lens disposed between the laser element and the optical element. <1> or the above <2> 2 is a light source device according to the first embodiment. <Item 4> The light source device according to <Item 3>, further comprising a support member disposed on the principal surface of the substrate and supporting each of the laser element and the lens, the support member having a first region in which the laser element is disposed and a second region in which the lens is disposed, and in a normal direction to the principal surface, a height of an upper surface of the first region relative to the principal surface and a height of an upper surface of the second region relative to the principal surface are adjusted so that a central axis of the laser light emitted from the laser element and an optical axis of the lens are aligned. <Item 5> The light source device according to any one of <Item 1> to <Item 4>, wherein the first surface is a mirror having a predetermined reflectance, and the second surface is either a total reflection mirror or a dichroic mirror. <Item 6> The second surface is provided with a metal film or a dielectric multilayer film. <5> 2 is a light source device according to the first embodiment. <Item 7> The light source device according to any one of <Item 1> to <Item 6>, wherein the polarizing element is a half-wave plate. <Item 8> The light source device according to any one of <Item 1> to <Item 7>, further comprising a housing member that houses the laser element and the optical element, and a lid portion that seals the housing member. <Item 9> The light source device according to any one of <Item 1> to <Item 8>, further comprising an optical multiplexer that multiplexes the first component and the second component of the laser light. <Item 10> The light source device described in <Item 8> above, further comprising an optical multiplexer that multiplexes the first component and the second component of the laser light, the optical multiplexer being a prism that reflects one of the first component and the second component two or more times and transmits the other of the first component and the second component to multiplex the first component and the second component, the optical multiplexer being provided on the lid portion. <Item 11> A display device comprising: a light source device according to any one of items <1> to <8>; and an optical multiplexer that multiplexes the first component and the second component of the laser light emitted from the light source device. <Item 12> A display device including three or more light source devices according to any one of <Item 1> to <Item 10>, wherein the three or more light source devices emit at least red, blue and green laser light. [Explanation of symbols]

[0085] 1 Board 10 Main Surface 2, 2a, 2R, 2G, 2B laser elements 3, 3a, 3R, 3G, 3B optical elements 31 Page 1 32 2nd page 33 Top surface 34 Bottom surface 4, 4a, 4R, 4G, 4B polarizing elements 5, 5a, 5R, 5G, 5B Lenses 50 Optical axis 6, 6a, 6R, 6G, 6B Support members 61 1st area 610 1st top surface 62 Second area 620 2nd top surface 7 Optical element support member 8. Storage material 80 Recess 9 Lid 11, 11R, 11G, 11B optical multiplexer 111 First prism surface 112 Second prism surface 113 Concave Lens 114 Convex Lens 12 First lens 13 Dichroic Prism 14 Second lens 15 Light Diffuser 16 Third lens 17 Light homogenization optical system 171 First Lens Array 172 Second Lens Array 173 4th lens 100, 100a, 100b, 100R, 100G, 100B light source device 200, 200a display device 210 Laser element driver 220 Optical Scanning Mechanism h1 First height h2 Second height L, LR, LG, LB laser light L0 center axis L1 1st component L2 2nd component α First angle β Second angle

Claims

1. A substrate; a laser element disposed on a main surface of the substrate and configured to emit laser light; an optical element disposed on a main surface of the substrate and in an optical path of the laser light; a polarizing element disposed on the optical element; The optical element is a first surface that reflects upward a first component of the laser light incident from the laser element; a second surface that reflects upward a second component of the laser light incident from the laser element and transmitted through the first surface, a light source device that emits a first component of the laser light that is not transmitted through the polarizing element, and a second component of the laser light that is transmitted through the polarizing element.

2. the smaller of the angles between the first surface and the main surface of the substrate is a first angle α; The light source device according to claim 1 , wherein the smaller of the angles formed between the second surface and the main surface of the substrate is a second angle β smaller than the first angle α.

3. The light source device according to claim 1 , further comprising a lens disposed between the laser element and the optical element.

4. a support member disposed on the main surface of the substrate and supporting the laser element and the lens, the support member has a first region in which the laser element is disposed and a second region in which the lens is disposed, 4. The light source device of claim 3, wherein in a normal direction to the principal surface, a first height of a first upper surface of the first region relative to the principal surface and a second height of a second upper surface of the second region relative to the principal surface are adjusted so that a central axis of the laser light emitted from the laser element and an optical axis of the lens are aligned.

5. the first surface is a mirror having a predetermined reflectance; 2. The light source device according to claim 1, wherein the second surface is either a total reflection mirror or a dichroic mirror.

6. The light source device according to claim 5 , wherein the second surface comprises a metal film or a dielectric multilayer film.

7. The light source device according to claim 1 , wherein the polarizing element is a half-wave plate.

8. a housing member that houses the laser element and the optical element; The light source device according to claim 1 , further comprising a lid portion that seals the housing member.

9. The light source device according to claim 1 , further comprising an optical multiplexer that multiplexes the first component and the second component of the laser light.

10. an optical multiplexer that multiplexes the first and second components of the laser light; the optical multiplexer is a prism that reflects one of the first component and the second component two or more times and transmits the other of the first component and the second component to multiplex the first component and the second component; The light source device according to claim 8 , wherein the optical multiplexer is provided on the lid portion.

11. A light source device according to any one of claims 1 to 8, an optical multiplexer that multiplexes the first component and the second component of the laser light emitted from the light source device.

12. A light source device according to any one of claims 1 to 10, The three or more light source devices emit at least red, blue and green laser beams.

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