JP2013029794A - Linear light source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a linear light source device that has even luminance distribution with fewer light emitting elements.SOLUTION: The linear light source device comprises: a light emitting point 96 able to emit a light beam 16 and having a light beam cross-section that has a long axis 92 and a short axis 94 perpendicular to the long axis and shorter than the long axis; a light guide body 20 able to guide the light beam and having a light beam incidence face 20a, an end face 20d of the light guide body provided opposite the incidence face, a first face 20b extending in the direction of light guide, and an emission face 20c provided opposite the first face and extending in the direction of light guide; and a phosphor layer 30 configured to absorb the light beam transmitted through the first face of the light guide body, able to emit wavelength conversion light of a wavelength longer than that of the light beam, and intersecting none of straight lines including the long axis in the cross-section of the light beam. The light beam and the wavelength conversion light can be emitted from the emission face.

Description

  Embodiments described herein relate generally to a linear light source device.

  For example, white light or a light bulb color can be obtained by mixing emission light in the wavelength range of ultraviolet light to visible light and wavelength conversion light emitted by a phosphor that has absorbed the emission light.

  As such a light emitting device, for example, there is an SMD (Surface Mounted Device) type device in which phosphor particles are mixed and a chip of a surface emitting nitride-based light emitting element is covered with a sealing layer containing a transparent resin. . When a surface light emitting element is used, the spread angle of the far-field image is large. For this reason, light cannot enter the linear light guide efficiently. Therefore, it is difficult to realize a high-luminance linear light source device with this light guide system. In order to realize a high-luminance linear light source with this surface light emitting element, it is necessary to arrange a large number of surface light emitting elements at high density. However, with this method, it is difficult to completely eliminate the light emission from the surface and realize continuous linear light emission.

  On the other hand, the spread angle of the light beam of the semiconductor laser element is small. For this reason, a light beam can be efficiently introduced into one end of the linear light guide. At this time, the phosphor layer is continuously provided in a thin line shape along the light guide, and is excited by the semiconductor laser light being guided. Therefore, in this method, continuous linear light emission that is not smooth can be realized. There is also an advantage that the number of elements can be reduced. However, a large amount of light beam is easily absorbed by the phosphor layer on one end side which is the incident side, the intensity of the light beam reaching the other end of the light guide is reduced, and is uniform along the light guide direction. There arises a problem that it is difficult to obtain a luminance distribution.

Japanese Patent No. 3434726

  Provided is a linear light source device having a uniform luminance distribution with a small number of light emitting elements.

  The linear light source device according to the embodiment is a light emitting point capable of emitting a light beam, and a cross section of the light beam is perpendicular to the major axis and the major axis and is equal to or less than the length of the major axis. A light emitting point having a short axis having a length; and a light guide capable of guiding the light beam, wherein the light beam is provided on an opposite side of the incident surface of the light beam. A light guide having an end face of the light body, a first surface extending in the light guide direction, and an exit surface provided on a side opposite to the first surface and extending in the light guide direction; A phosphor layer capable of absorbing the light beam transmitted through the first surface of the light guide and emitting wavelength-converted light having a wavelength longer than the wavelength of the light beam, A phosphor layer that does not intersect a straight line including the major axis in a cross section, and the light beam and the wavelength-converted light are It can be emitted from the morphism surface.

  A linear light source device having a uniform luminance distribution with a small number of light emitting elements is provided.

1A is a schematic perspective view of the linear light source device according to the first embodiment, FIG. 1B is a cross-sectional view of the optical fiber along the line FF, and FIG. 1C is a line AA. FIG. 1D is a schematic cross-sectional view of an end portion of the light guide along the line BB. FIG. 2A is a schematic perspective view of the linear light source device according to the second embodiment, FIG. 2B is a schematic cross-sectional view of the light guide along the line AA, and FIG. FIG. 2D is a schematic perspective view in which a laser device of a CAN type package is partially cut. It is a graph which shows the luminance distribution of the linear light source device concerning 1st and 2nd embodiment. 4A is a schematic diagram showing the spread of the light beam of the linear light source device according to the comparative example, FIG. 4B is a schematic cross-sectional view thereof, and FIG. 4C is the linear light source device according to the comparative example. It is a graph which shows luminance distribution. 5A is a schematic cross-sectional view of a linear light source device of a first modification of the second embodiment, FIG. 5B is a schematic cross-sectional view of the second modification, and FIG. 5C is a third modification. It is a schematic cross section of an example. FIG. 6A is a schematic perspective view of the linear light source device according to the third embodiment, and FIG. 6B is a partial schematic cross-sectional view taken along the line CC. 7A shows a vertical half-width of 15 degrees, FIG. 7B shows a half-width of 10 degrees, FIG. 7C shows a half-width of 5 degrees, FIG. 7D shows a half-width of 2 degrees, The FFP of the light beam is shown. FIG. 8A is a schematic cross-sectional view illustrating the unit length of the rectangular cross-section light guide for standardizing the position in the z direction, and FIG. 8B is a schematic cross-sectional view illustrating the unit length of the light guide on the circular exit surface. . FIG. 9 is a graph showing the luminance dependence of excitation light with respect to the z-direction position. FIG. 9A shows a vertical half-width of 15 degrees, FIG. 9B shows a half-width of 10 degrees, and FIG. FIG. 9C is a graph showing the relative luminance when the half-value half angle is 5 degrees and FIG. 9D is the half-value half angle is 2 degrees.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1A is a schematic perspective view of the linear light source device according to the first embodiment, FIG. 1B is a cross-sectional view of the optical fiber along the line FF, and FIG. 1C is a line AA. FIG. 1D is a schematic cross-sectional view of the end portion along the line BB.
The linear light source device has at least a light emitting point 96 provided on the emission end face of the optical fiber 90, the light guide 20, and the phosphor layer 30.

  The light guide 20 is provided on the side opposite to the incident surface 20a of the light beam 16 from the light emitting point 96, the first surface 20b extending in the light guide direction 22, and the first surface 20b. It has an exit surface 20c extending in the direction 22, an end surface 20d of the light guide 20 on the side opposite to the entrance surface 20a, a side surface 20e, and a side surface 20f. The light guide 20 can guide the light beam 16 in the extending direction while reflecting the light beam 16. If the light guide 20 is made of a light-transmitting material such as transparent resin (refractive index: 1.4 to 1.8) or glass, the light beam 16 is guided by total reflection at the interface with air or the like. Can shine.

  As shown in FIG. 1B, the optical fiber 90 has a core 90a and a clad 90b. For example, the emitted light from the light emitting element 10 enters from one end face of the optical fiber 90 and exits from the other end face (exit end face). That is, the vicinity of the core 90 a in the emission end face is the light emission point 96. In the first embodiment, the cross section of the light beam 16 emitted from the light emitting point 96 has a major axis 92 and a minor axis 94 that is perpendicular to the major axis 92 and has a length equal to or less than the length of the major axis 92. And.

  The phosphor layer 30 can absorb the light beam 16 transmitted through the first surface 20 b of the light guide 20 and emit wavelength converted light g <b> 2 having a wavelength longer than the wavelength of the light beam 16. If the light beam 16 includes an InGaAlN-based material, the wavelength of the light beam 16 can be in the ultraviolet to blue light wavelength range. In this case, when the phosphor layer 30 includes a yellow phosphor, it is possible to obtain outgoing light G1 that is pseudo white light as a mixed color. Further, white light can be obtained even when the phosphor layer 30 includes a red phosphor and a green phosphor. In addition, the assembly process of the linear light source device can be simplified by applying the phosphor layer 30 to the light guide 20 in advance, or by bonding them together using a transparent double-sided tape or the like.

  The linear light source device may have a reflector 40 made of a metal such as aluminum on the surface of the phosphor layer 30 on the opposite side of the light guide 20. The reflector 40 can reflect a part g1 of the light beam 16 and the wavelength-converted light g2 transmitted through the phosphor layer 30 toward the emission surface 20c. If the gap between the reflector 40 and the phosphor layer 30 can be reduced, the reflectance can be further increased. Moreover, the reflective material 40 can be made into the layer which apply | coated barium sulfate etc. with high reflectance to the outer side of the fluorescent substance layer 30, for example.

  The reflective material 40 may be provided so as to cover the side surfaces 20e and 20f of the light guide 20 on which the phosphor layer is not provided, as shown in FIG. In this way, it becomes easy to dissipate the heat generated in the phosphor layer 30 by absorbing a part of the light beam 16 to the outside via the reflector 40. When no gap is provided between the side surfaces 20 e and 20 f and the reflective material 40, the light beam 16 is reflected mainly on the surface of the reflective material 40 and travels along the light guide direction 22.

  In addition, as shown in FIG. 1C, the light guide 20 is rectangular in a cross section perpendicular to the light guide direction 22. The cross-sectional shape is not limited to this. The phosphor layer 30 is provided between the reflector 40 and the first surface 20b of the rectangular light guide 20. In the first embodiment, the phosphor layer 30 is provided so as not to intersect the straight line including the long axis 92 of the light beam 16 in the cross section of FIG. Further, a part g1 of the light beam 16 and the wavelength-converted light g2 can be emitted from the emission surface 20c, and the mixed color G1 can be generated.

  As shown in FIG. 1D, when a reflection layer 50 such as a silver reflection sheet is provided on the end surface 20d opposite to the incident surface 20a, the light beam 16 is reflected in a direction opposite to the light guide direction 22. The brightness in the vicinity of the end face 20d can be increased. In addition, leakage of the light beam 16 to the outside can be suppressed, and safety is improved.

FIG. 2A is a schematic perspective view of the linear light source device according to the second embodiment, FIG. 2B is a schematic cross-sectional view of the light guide along the line AA, and FIG. FIG. 2D is a schematic perspective view in which a laser device of a CAN type package is partially cut.
In the second embodiment, the light beam 16 emitted from the light emitting device 10 enters the light guide 20. The light emitting element 11 includes a semiconductor stacked body 12 provided on a substrate 15. The semiconductor stacked body 12 includes a first layer having a first conductivity type, a second layer having a second conductivity type, and a light emitting layer 14 provided between the first layer and the second layer. ,including. That is, the light emitting point 96 is a partial region of the side surface of the light emitting layer 14 constituting the light emitting element 11 in the light emitting device 10.

  The light emitting layer 14 may have a multi quantum well (MQW) structure including a well layer and a barrier layer. With the MQW structure, it becomes easy to control the emission wavelength and improve the emission efficiency.

Further, the semiconductor laminate _{12, In x Ga y Al 1-} x-y N (0 ≦ x ≦ 1,0 ≦ y ≦ 1, x + y ≦ 1) InGaAlN -based material _{consisting, In x (Ga 1-y} Al _y) may be, eg _{1-x P (0 ≦ x} ≦ 1,0 ≦ y ≦ 1) InGaAlP -based material consisting _{of, Al x Ga 1-x as} (AlGaAs -based material consisting of 0 ≦ x ≦ 1) . Note that these materials may further contain an element serving as an acceptor or a donor. The semiconductor laminate 12 can be formed by using a MOCVD (Metal Organic Chemical Vapor Deposition) method, an MBE (Molecular Beam Epitaxy) method, or the like.

  The phosphor layer 30 is provided apart from the light emitting device 10, absorbs the light beam 16 transmitted through the first surface 20 b of the light guide 20, and converts the wavelength converted light g <b> 2 having a wavelength longer than the wavelength of the light beam 16. It can be released.

  Furthermore, when the light emitting element 11 is made of an InGaAlP-based material, a linear light source device in the wavelength range of green to red light that is the band gap wavelength of the light emitting layer can be obtained without performing wavelength conversion.

  The light emitting element 11 is bonded to a mounting member made of a CAN type package having a glass window capable of transmitting the light beam 16. The electrode of the light emitting element 11 and the lead of the CAN package are connected by a bonding wire or the like. The mounting member may be a resin molded body integrated with the lead frame.

  The light emitting element 11 used in the linear light source device of the second embodiment can emit a light beam 16 having a small divergence angle. For example, a semiconductor LD (Laser Diode) capable of emitting the light beam 16 from the side surface 14b of the light emitting layer 14 or an edge emitting LED (Light Emitting Diode) can be used.

  When the light emitting element 11 in FIG. 2A is an LD, the side surface 14b of the light emitting layer 14 is preferably a mirror surface of an optical resonator. The light beam 16 is emitted while spreading along an optical axis 18 perpendicular to the side surface 14b. The light intensity distribution in the cross section of the light beam 16 is represented by a far field pattern. The full width at half maximum of the far-field image is called the spread angle. Of these, the spread angle in the parallel (or horizontal) direction to the surface 14a of the light emitting layer 14 is represented by θh, and the spread angle in the vertical direction is represented by θv.

  In the case of LD, light is confined by controlling the refractive index between the light emitting layer 14 and the cladding layer in the vertical (long axis) direction. In the horizontal (short axis) direction, a ridge waveguide or the like is provided to control the lateral mode. Thus, the optical confinement structure differs between the vertical direction and the horizontal direction. In general, the light emitting layer 14 is as thin as about 0.1 μm. On the other hand, the width of the ridge waveguide is 1 μm or more. For this reason, the vertical spread angle θv is greatly influenced by Fraunhofer diffraction and is usually larger than the horizontal spread angle θh. For example, the vertical spread is 15 to 20 degrees at half-value half angle (θv / 2), and the horizontal spread is about 5 degrees at half-value half angle (θh / 2). The light beam 16 thus narrowed can be efficiently incident on the incident surface 20 a of the light guide 20. For this reason, it can be set as the linear light source device which has a high brightness | luminance with few light emitting elements. Further, the light beam 16 usually has a TE wave (Transverse Electric Wave) electric field component in a direction parallel to the surface 14 a on the side surface 14 b and travels along the light guide direction 22.

  As shown in FIG. 2B, in the present specification, the vertical plane SV is defined as a plane that includes the optical axis 18 of the light beam 16 and intersects the surface 14 a of the light emitting layer 14 perpendicularly. In the case of LD, the vertical spreading direction can be the direction of the long axis 92 at the light emitting point 96 of the optical fiber 90.

  In FIG. 1C, the straight line including the major axis 92 is substantially parallel to the surface 30a of the phosphor layer 30, but may not be parallel as long as it does not intersect the phosphor layer 30. The light beam component 16h (chain line in FIG. 2A) horizontal to the surface 14a of the light emitting layer 14 has a smaller divergence angle than the light beam component 16v (dashed line) perpendicular to the surface 14a, so that the fluorescence provided on the first surface 20b. The number of incidences on the body layer 30 is small. For this reason, the light beam component 16h can easily keep the light intensity high up to the end surface 20d opposite to the incident surface 20a, and can excite the phosphor layer 30.

  On the other hand, since the spread angle of the light beam component 16v (broken line) perpendicular to the surface 14a of the light emitting layer 14 is large, the number of times of total reflection by the side surfaces 20e and 20f of the light guide 20 increases. However, since the phosphor layers are not provided on the side surfaces 20e and 20f, the light beam 16v can reach the vicinity of the end surface 20d. That is, excessive absorption by the phosphor layer 30 in the vicinity of the incident surface 20 a of the light guide 20 can be suppressed, and the phosphor layer 30 can be excited in a well-balanced manner along the light guide direction 22.

FIG. 3 is a graph showing the luminance distribution of the linear light source device according to the first and second embodiments.
The vertical axis represents relative luminance, and the horizontal axis represents the position (mm) in the direction of light guide from the incident surface 20a. A reflecting material 40 such as a white reflecting sheet is provided outside the phosphor layer 30, and a light diffusing sheet is provided on the emission surface 20c. If it does in this way, it will be suppressed that the light beam 16 leaks from other than the output surface 20c, and it will become easy to improve safety | security. In addition, the cross-sectional size of the light guide 20 was a rectangle of 2 mm × 2 mm, and the length along the light guide direction 22 was 100 mm.

  In the first and second embodiments, the luminance is maximized in the vicinity of the incident surface 20a and in the vicinity of the end surface 20d of the light guide 20. The minimum luminance value was 25% smaller than the maximum luminance value. The length along the light guide direction 22 that can keep the brightness between the minimum value and the maximum value generated on the end face 20d side was about 88% of the length of the light guide 20. That is, it can be said that the luminance is uniform. FIG. 3 shows the case where the phosphor layer 30 is a yellow phosphor, but it is easy to keep the luminance uniform even if the phosphor layer 30 is a red / green phosphor.

4A is a schematic diagram showing the spread of the light beam of the linear light source device according to the comparative example, FIG. 4B is a schematic cross-sectional view thereof, and FIG. 4C is the linear light source device according to the comparative example. It is a graph which shows luminance distribution.
The cross-sectional size of the light guide 20 was a rectangle of 2 mm × 2 mm, and the length along the light guide direction was 100 mm. The vertical surface SSV including the optical axis of the light beam 116 and intersecting the surface 30 a of the phosphor layer 30 substantially perpendicularly intersects the surface 30 a of the phosphor layer 30. That is, the light emitting element of FIG. Since the vertical divergence angle of the light beam 116 is larger than the horizontal divergence angle, the phosphor layer 30 tends to be excessively absorbed in a region near the incident surface 20a of the light guide 20 as shown in FIG. . For this reason, the light beam 116 is largely absorbed in the region close to the incident surface 20a of the light guide 20, and in the region close to the opposite end face 20d, the light intensity sufficient to excite the phosphor layer can be maintained. Can not.

  For this reason, the maximum luminance value BBM occurs on the incident surface 20a side, and gradually decreases as the distance from the incident surface 20a increases. That is, as shown in FIG. 4C, the length in the light guide direction that can maintain the luminance between the maximum value BBM and 75% of the maximum value is about 24% of the length of the light guide 20. It was difficult to make a short and highly uniform linear light source device.

5A is a schematic cross-sectional view of a linear light source device of a first modification of the second embodiment, FIG. 5B is a schematic cross-sectional view of the second modification, and FIG. 5C is a third modification. It is a schematic cross section of an example.
The cross section of the light guide 20 may not be rectangular. In any case, the phosphor layer 30 is provided so as not to intersect the vertical plane SV.

  In FIG. 5A, the emission surface 20c is a curved surface that protrudes upward above the vertical surface SV. In this case, the light guide 20 acts as a condensing lens that can collect the outgoing light G2 upward, and it is easy to increase the luminance.

  In FIG. 5B, the reflector 40 has a first bent portion 40 a and a second bent portion 40 b in a cross section perpendicular to the light guide direction 22. The phosphor layer 30 is provided between the first region 30b provided between the light guide 20 and the first bent portion 40a, and between the light guide 20 and the second bent portion 40b, and the first region 30b. And a second region 30c spaced apart from each other. The reflection direction of the light beam 16 and the wavelength converted light 32 differs between the first bent portion 40a and the second bent portion 40b. That is, the outgoing light G3 has two centers in the light distribution direction. In this case, the emission surface 20c is a curved surface that protrudes upward above the vertical surface SV. The first surface 20b is a curved surface below the vertical surface SV. Furthermore, the light distribution direction can be controlled by changing the inclination of the first bent portion 40b and the second refracting portion 40b.

  In FIG.5 (c), let the cross section of the light guide 20 be a triangle. The outgoing light G4 has two centers of light distribution characteristics according to the inclinations of the two sides of the triangle. The cross-sectional shape is not limited to a triangle and can be a polygon. In this case, the first surface 20b is a surface on the bottom side of the triangle, and the emission surface 20c is a surface on the two sides other than the bottom side.

FIG. 6A is a schematic perspective view of the linear light source device according to the third embodiment, and FIG. 6B is a partial schematic cross-sectional view taken along the line CC.
The linear light source device includes at least light emitting devices 10a and 10b, a light guide 20, and a phosphor layer.

  As illustrated in FIG. 6A, the light guide 20 includes an incident surface 20 a on which the light beam 16 from the light emitting device 10 a is incident, a first surface 20 b extending in the light guide direction 22, and a first surface. It has an exit surface 20c provided on the side opposite to 20b and extending in the light guide direction 22, and an end surface 20g on the side opposite to the entrance surface 20a on which the light beam 17 from the light emitting device 10b is incident. The light guide 20 guides the light beam 16 and the light beam 17 in opposite directions while reflecting the light beam 16 and the light beam 17. For example, a light beam that spreads in a direction perpendicular to the surface of the light emitting layer is indicated by 16v and 17v. Further, beams that spread in a direction parallel to the surface of the light emitting layer are indicated by 16h and 17h.

  In the third embodiment, no reflective layer is provided on the incident surface 20a of the light guide 20, and no reflective layer is provided on the end surface 20g.

  The phosphor layer is provided so as to be in contact with the first surface 20b of the light guide 20, absorbs the light beams 16, 17 transmitted through the first surface 20b, and has a wavelength longer than that of the light beams 16, 17. The wavelength-converted light g2 it has can be emitted. It is assumed that the wavelength of the light beam 16 and the wavelength of the light beam 17 are substantially the same.

  The light beam 16 and the light beam 17 are, for example, LD light and have FFPs as shown in FIG. As shown in FIG. 6B, the light beam 16 exhibits a Gaussian distribution, and the spread angle of the intensity distribution I (θ) can be made narrower than the spread angle of the surface light emitting element having a Lambertian distribution. However, the region Sj (j = 1, 2, 3,...) Reflected by the light guide 20 increases as the light guide direction 22 is advanced. The luminance in the region Sj decreases in inverse proportion to the area of the region Sj. That is, the luminance decreases with the distance z from the incident surface 20a.

  7A shows a vertical half-width of 15 degrees, FIG. 7B shows a vertical half-width of 10 degrees, FIG. 7C shows a vertical half-width of 5 degrees, and FIG. 7D shows a vertical direction. The FFP of a light beam with a half-value half angle of 2 degrees is shown. When the light emitting devices 10a and 10b are LDs, it is easy to set the half value half angle (θv / 2) to 15 degrees or less. For this reason, it can enter into the light guide 20 with high efficiency.

FIG. 8A is a schematic cross-sectional view for explaining the unit length of the rectangular cross-section light guide for normalizing the position in the z direction, and FIG. 8B is a schematic cross-sectional view for explaining the unit length of the light guide on the circular emission surface. .
The phosphor layer 30 is provided so as to be perpendicular to the surface of the light emitting layer and not to intersect a vertical plane including the optical axis 18 of the light beam. For example, as shown in FIG. 8A, the vertical plane can be provided substantially parallel to the phosphor layer 30. In FIG. 6A, the phosphor layer 30 can be uniformly provided along the light guide direction 22 while being in contact with the surface 20 b of the light guide 20. In this way, approximately 5% or more of the light intensity of the LD becomes wavelength converted light, or is emitted as scattered light from the emission surface 20c, and can satisfy the required luminance as a linear light source device.

  Fig.8 (a) is a schematic cross section along the AA line of Fig.6 (a). In the case of the rectangular cross-section light guide 20, the position z from the incident surface 20 a is normalized using a length that is ½ of the thickness TS of the light guide 20. 8B, the position z from the incident surface 20a is normalized using one half of TC, which is the diameter of the circle of the output surface 30c.

FIG. 9 is a graph showing the luminance dependence of the excitation light with respect to the normalized position z. That is, FIG. 9A shows a vertical half-width (θv / 2) of 15 degrees, FIG. 9B shows a vertical half-width of 10 degrees, and FIG. 9C shows a vertical half-width of 5 degrees. 9 (d) is a graph showing the relative luminance when the vertical half-width is 2 degrees.
The vertical axis represents the relative luminance obtained by simulation, and the horizontal axis represents the normalized position z. That is, the position z = 0 indicates the incident surface 20a, and the position z = 500 indicates the end surface 20g.

  The light beam 16 enters from z = 0, and the light beam 17 enters from z = 500. The luminance of the excitation light by the light beam 16 is indicated by a broken line, and the luminance of the excitation light by the light beam 17 is indicated by a chain line. Also. The overall luminance is indicated by a solid line. Further, 5% of the excitation light is absorbed by the phosphor layer 30 and emits wavelength-converted light.

  In the case of FIG. 9A in which the half value half angle is 15 degrees, the maximum value of luminance is generated in the vicinity of the incident surface 20a and the end surface 20d. In addition, a minimum luminance value is generated near the center. Since the minimum value of luminance is as low as about 48% of the maximum value, it cannot be said to be sufficient as a linear light source.

  On the other hand, in the case of FIG. 9B in which the half value half angle is 10 degrees, the luminance minimum value is approximately 70% of the maximum value and becomes uniform. In the case of FIG. 9C where the half-width half angle is 5 degrees, the brightness minimum value can be made more uniform, approximately 93% of the maximum value. That is, the half value half angle is more preferably around 5 degrees.

  In the case of FIG. 9D where the half value half angle is as narrow as 2 degrees, the maximum value of the luminance is near the center of the light guide 20. A slight minimum occurs in the vicinity of the incident surface 20a and in the vicinity of the end surface 20g. If the half value half angle is smaller than 2 degrees, it is necessary to improve the accuracy of the incident angle to the light guide 20. Further, the distance from the incidence of the light beams 16 and 17 to the surface of the light guide 20 becomes longer, the luminance starts to further decrease in the vicinity of the incident surface 20a and the end surface 20d, and the luminance is at a uniform position z. The range of becomes narrower. Thus, it is preferable that the half value half angle is 2 degrees or more and 10 degrees or less.

  Note that if the half-value half-angle is reduced, the range of the position z at which the luminance is uniform can be widened. Therefore, the light-emitting device 10 may be provided only on one side. For example, in FIG. 9D, the range of the position z where the excitation light luminance (broken line) by the light beam 16 is 70% or more of the maximum value is as wide as 20 to 500, so that it can be used as a linear light source device.

  In FIG. 9C, the range of the position z where the excitation light luminance is 70% or more of the maximum value is 10 to 260, and can be used as a linear light source device with uniform luminance within this range. Further, in FIG. 9B, the range of the position z where the excitation light luminance is 70% or more of the maximum value is 0 to 130, and can be used as a linear light source device having uniform luminance within this range.

  When the linear light source device according to the first to third embodiments and the modifications associated therewith is used, the light beam of the light emitting element can be efficiently incident on the light guide, and the surface line has a uniform luminance distribution. A shaped light source device can be obtained. In addition, when an LD is used as a light emitting element, a light beam can be efficiently introduced into the light guide, so that the number of light emitting elements is reduced and the power consumption of the linear light source device can be easily reduced.

  Further, when the outgoing lights G1, G2, G3, and G4 from such a linear light source device are incident along the side surface of the planar light guide plate, it is easy to obtain a planar light source device. Such a planar light source device can be widely used for a backlight of an image display device, a high brightness illumination device, a high brightness display device, and the like.

  The embodiments of the present invention have been described above with reference to the drawings. However, the present invention is not limited to these embodiments. Even if a person skilled in the art makes various design changes regarding the material, shape, size, arrangement, etc. of the light guide, phosphor layer, light emitting element, reflector, etc. constituting the present invention, the gist of the present invention Unless it deviates from, it is included in the scope of the present invention.

DESCRIPTION OF SYMBOLS 10 Light emitting device, 11 Light emitting element, 12 Semiconductor laminated body, 14 Light emitting layer, 14a The surface of a light emitting layer, 14b The side surface of a light emitting layer, 16, 16v, 16h Light beam, 17, 17v, 17h Light beam, 18 Optical axis, 20 Light guide, 20a entrance surface, 20b first surface, 20c exit surface, 20d, 20g, end surface, 20e side surface, 20f side surface, 22 light guide direction, 30 phosphor layer, 30b first region, 30c second region, 40 reflective material, 40a first bent portion, 40b second bent portion, 50 reflective layer, 90 optical fiber, 92 long axis, 94 short axis, 96 emission point, g1 light beam, g2 wavelength converted light, G1, G2, G3, G4 outgoing light, θv vertical divergence angle, θh horizontal (or parallel) divergence angle, SV vertical plane with respect to light emitting layer surface including optical axis

Claims (9)

A light emitting point capable of emitting a light beam, wherein the cross section of the light beam has a major axis and a minor axis perpendicular to the major axis and having a length equal to or less than the length of the major axis. Luminous point;
A light guide capable of guiding the light beam, the light beam incident surface, an end surface of the light guide provided on the opposite side of the light incident surface, and a light guide extending in the light guide direction A light guide having a surface of 1 and an emission surface provided on a side opposite to the first surface and extending in the light guide direction;
A phosphor layer capable of absorbing the light beam transmitted through the first surface of the light guide and emitting wavelength-converted light having a wavelength longer than the wavelength of the light beam, wherein the cross section of the light beam A phosphor layer that does not intersect with a straight line including the long axis,
With
The linear light source device characterized in that the light beam and the wavelength-converted light can be emitted from the emission surface. The light emitting point is a part of the region of the exit end face of the optical fiber that guided the emitted light from the light emitting element,
2. The linear light source device according to claim 1, wherein a direction perpendicular to the surface of the light emitting layer is a direction in which the major axis extends. The light emitting point is a part of a side region of the light emitting layer of the light emitting element,
2. The linear light source device according to claim 1, wherein a direction perpendicular to the surface of the light emitting layer is a direction in which the major axis extends.   The linear light source device according to claim 1, further comprising a reflective layer provided on the end face of the light guide.   It further includes a reflective material that is provided so as to cover the surface of the phosphor layer on the side opposite to the light guide, and that can reflect the light beam and the wavelength-converted light toward the emission surface. The linear light source device according to claim 1, wherein: The reflector has a first bent portion and a second bent portion in a cross section perpendicular to the light guide direction,
The phosphor layer is provided between a first region provided between the light guide and the first bent portion, and between the light guide and the second bent portion, and the first region, A second region spaced apart,
The linear light source device according to claim 5, wherein reflection directions of the light beam and the wavelength-converted light are different between the first bent portion and the second bent portion.   The said light guide is any one of a rectangle, a polygon, and the shape from which the said output surface becomes convex in the cross section perpendicular | vertical with respect to the said light guide direction, The any one of Claims 1-6 characterized by the above-mentioned. The linear light source device according to one.   4. The linear light source device according to claim 2, wherein a spread of the light emitting element in the vertical direction is not less than 2 degrees and not more than 10 degrees in a half value half angle. The light emitting element includes a first light emitting element and a second light emitting element,
The light beam of the first light emitting element is introduced from the incident surface to the light guide,
The linear light source device according to claim 8, wherein the light beam of the second light emitting element is introduced into the light guide from the end face.

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