JP2006332411A - Light emitting device, light receiving device and equipment provided with them - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small-sized light emitting device capable of uniformly emitting light from the emission of an optical member. <P>SOLUTION: The light emitting device is provided with a light emitting element 1 and the optical member 9. The optical member is provided with a first emitting surface 6 for emitting light emitted from the light emitting element to an irradiation light axis AXL at an angle smaller than a prescribed angle, a reflecting surface 7 for reflecting light emitted from the light emitting element to the irradiation light axis at an angle larger than the prescribed angle, and a second emitting surface 8 formed around the first emitting surface for emitting the light reflected on the reflecting surface. The second emitting surface has a shape that a part most separated from the irradiation light axis is projected in the opposite direction of the light emitting element in an irradiation light axis direction more than a part closest to the irradiation light axis. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention provides a light emitting device that can efficiently use light emitted from a light emitting element such as a light emitting diode (LED) or a semiconductor laser (LD) or light incident on a light receiving element such as a photodiode or a photoelectric conversion element. And a light receiving device.

  A light emitting device in which a light emitting element chip such as an LED or LD is sealed with a mold resin has been used. In such a light emitting device, the light emitted forward from the light emitting element is emitted as it is from the resin portion, but the light emitted from the light emitting element in the oblique direction is totally reflected at the interface of the resin portion or the inner surface of the case The amount of light is lost due to scattering by the light, and the light utilization efficiency is lowered.

  In view of this, a light emitting device that can efficiently use light emitted in an oblique direction from a light emitting element is disclosed in Patent Document 1. A cross section of this light emitting device is shown in FIG.

  The light-emitting device shown in FIG. 9 includes a light-emitting element 61, a first lead frame 63 that is die-bonded by mounting the light-emitting element 61 on a holding portion 62, and a second lead that is connected to the light-emitting element 61 by a bonding wire 64. The lead frame 65 includes a reflection member 66 provided around the lead frame 65 and an optical member 69 formed of a mold resin that seals the light emitting element 61 and the reflection member 66. On the light emission side of the optical member 69, a direct emission region 67 having a convex lens shape is formed at the center, and a planar surface 68 extending around the direct emission region 67 in a direction orthogonal to the irradiation optical axis AXL. Is formed. A portion 70 of the surface 68 close to the direct emission region 67 is used as a total reflection region, and the total reflection region 70 totally reflects light from the light emitting element 61 toward the reflection member 66. Further, a portion around the total reflection region 70 is used as an emission region of light reflected by the reflection member 66.

  Patent Document 1 also discloses a light receiving device in which a light receiving element such as a photodiode or a photoelectric conversion element is sealed with a mold resin. As shown in FIG. 10, the light receiving device is formed of a reflecting member 76, a light receiving element 71, first and second lead frames 72 and 73, and a mold resin that seals the reflecting member 76 and the light receiving element 71. And an optical member 79. On the incident side of the optical member 79, a direct incident region 77 having a convex lens shape is formed at the center, and a planar surface 78 extending in a direction orthogonal to the incident optical axis AXL is formed around the center. Yes. A portion 80 of the surface 78 close to the direct incident region 77 is further used as a total reflection region that totally reflects toward the light receiving element 71 light incident from the incident region that is a surrounding portion thereof and reflected by the reflecting member 76. ing.

  Here, in the light emitting device shown in FIG. 9, the angle formed with respect to the irradiation optical axis AXL in the direction L extending directly from the light emitting element 61 to the boundary between the emission region 67 and the surface 68 is between the optical member 69 and the air. It is set equal to or greater than the critical angle for total reflection at the interface. For this reason, in the light emitting device of FIG. 9, no light is emitted from the total reflection region 70, and the irradiated surface is irradiated with donut-shaped light. That is, a dark portion is generated at the center of the irradiated surface, and it appears that there is uneven light emission.

  In the light receiving device shown in FIG. 10 as well, the angle formed by the incident optical axis AXL in the direction L extending to the boundary between the direct incident region 77 and the surface 78 is the total reflection critical at the interface between the optical member 79 and air. It is set equal to or larger than the angle. For this reason, in the light receiving device of FIG. 10, the light that has entered the total reflection region 80 from the reflecting member 76 does not enter the light receiving element 71 and is emitted outside the light receiving device. That is, the amount of received light decreases.

  Further, in the light emitting device shown in FIG. 9 or the light receiving device shown in FIG. 10, in order to improve the light emission efficiency or the light receiving efficiency, light emitted from the light emitting element in an oblique direction or light incident on the light receiving element from an oblique direction If the angle formed with the optical axis AXL is increased, the total reflection area must be extremely increased, and the apparatus becomes larger.

Therefore, Patent Document 2 discloses a light emitting device in which the interface between the resin and the air forming the total reflection region is extended to a position closer to the optical axis (inside) than the outer periphery of the lens surface. In this light emitting device, the light reflected at the position closest to the optical axis in the total reflection region passes through the vicinity of the outer periphery of the lens surface when being reflected by the reflecting member and emitted forward. This eliminates a region where light is not emitted in front view (a region where light is not incident in the light receiving device), and at the same time, the device can be downsized.
JP 2002-94129 A (paragraphs 0057 to 0063, 0112 to 0118, FIGS. 3, 31 and the like) JP 2002-134794 A (paragraphs 0023 to 0027, FIG. 1, etc.)

  However, in the light emitting device or the light receiving device disclosed in Patent Document 2, light emitted from the light emitting element in the oblique direction or light incident on the light receiving element from the oblique direction is reflected by the reflecting member, and thus the light amount loss. There is a problem that is large.

  In addition, by extending the total reflection region to the inner side of the outer periphery of the lens surface, there is a problem that the shape of the optical member becomes complicated and manufacturing becomes difficult and the number of parts increases.

  An object of the present invention is to provide a small light-emitting device and light-receiving device that can uniformly emit light from an emission part of an optical member and reduce light emission loss and light reception loss as much as possible.

  A light emitting device according to one aspect of the present invention includes a light emitting element and an optical member. The optical member emits light emitted from the light emitting element at an angle smaller than a predetermined angle with respect to the irradiation optical axis and emitted from the light emitting element at an angle larger than the predetermined angle with respect to the irradiation optical axis. A reflection surface that reflects the emitted light, and a second emission surface that is formed around the first emission surface and emits the light reflected by the reflection surface. The second emission surface has a shape in which a portion farthest from the irradiation optical axis protrudes in a direction opposite to the light emitting element in the irradiation optical axis direction than a portion closest to the irradiation optical axis.

  A light receiving device according to one aspect of the present invention includes a light receiving element and an optical member. The optical member is formed so that the incident optical axis passes, and a first incident surface that directs incident light to the light receiving element; a second incident surface formed around the first incident surface; And a reflecting surface that reflects light incident from the second incident surface toward the light receiving element. The second incident surface has a shape in which the portion farthest from the incident optical axis protrudes in the direction opposite to the light receiving element in the incident optical axis direction than the portion closest to the incident optical axis.

  These light emitting devices and light receiving devices are mounted on various devices that require a light emitting function and a light receiving function, and contribute to downsizing of the devices.

  According to the light emitting device of the present invention, most of the light emitted from the light emitting element is directed to the peripheral portion from the first emission surface is reflected by the reflection surface, and is provided around the first emission surface. In addition, since the light is guided to the second emission surface, the light emission from the light emitting element can be efficiently emitted with little unevenness in light emission even though it is small.

    Further, according to the light receiving device of the present invention, most of the light incident from the second incident surface provided around the first incident surface of the optical member is reflected by the reflecting surface and guided to the light receiving element. Although it is small, incident light can be received efficiently.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows the appearance of a light emitting device that is Embodiment 1 of the present invention. FIG. 2 shows a cross section when the light emitting device is cut along a plane including the emission optical axis AXL. Further, FIG. 2 also shows a trace diagram of light rays emitted from the light emitting element.

  1 and 2, reference numeral 1 denotes a light emitting element such as an LED or LD, 3 denotes a first lead frame having a holding portion 2 which is die-bonded in a state where the light emitting element 1 is mounted, and 4 denotes a light emitting element 1 and a second lead frame. A bonding wire that connects the lead frames 5.

  Reference numeral 9 denotes an optical member molded with an optical resin material so as to seal the light emitting element 1 and the portions of the lead frames 3 and 5 on the light emitting element 1 side. The optical resin material is preferably a heat resistant material such as epoxy resin or silicon.

  In the optical member 9, reference numeral 6 denotes a lens surface as a first exit surface that has a positive refractive power with respect to incident light from the light emitting element 1 and is formed so that the irradiation optical axis AXL passes through the center thereof. The lens surface 6 is formed in a convex lens shape such as a spherical lens shape, an aspheric lens shape, or a paraboloid shape. Of the light emitted from the light emitting element 1, light having an angle θ1 smaller than a predetermined angle with respect to the irradiation optical axis AXL (hereinafter referred to as first light) is directly incident on the lens surface 6 to collect the light. It is injected while being done. Reference numeral 7 denotes a reflection surface (hereinafter referred to as second light) that is incident on an angle θ2 that is equal to or larger than the predetermined angle with respect to the irradiation optical axis AXL among the light emitted from the light emitting element 1 and that totally reflects the incident light. Internal reflection surface).

  Reference numeral 8 denotes a second emission surface on which the light totally reflected by the reflection surface 7 is incident, refracted and emitted forward (in the irradiation optical axis direction, that is, the right side in FIG. 2). Here, as shown in FIG. 2, the second emission surface 8 is formed as a surface having a truncated cone shape including a line L that is inclined from the approximate center of the light emitting element 1 with respect to the irradiation optical axis AXL. Yes. In other words, the second emission surface 8 has the light emitting element 1 in the irradiation optical axis direction in which the portion (outer peripheral portion) farthest from the irradiation optical axis AXL is closer than the portion (inner peripheral portion) closest to the irradiation optical axis AXL. It has a shape protruding in the opposite direction (irradiation direction). Further, the inner periphery of the second exit surface 8 is in contact with the outer periphery of the lens surface 6.

  In the light emitting device of the present embodiment, the first light having a small angle with respect to the irradiation optical axis AXL among the light emitted from the light emitting element 1 is disposed at or near the focal point of the lens surface 6. The light is refracted by the lens surface 6 that forms the interface between the optical member 9 and air, and is emitted from the lens surface 6 as light substantially parallel to the irradiation optical axis AXL. In addition, the second light whose angle with respect to the irradiation optical axis AXL is larger than the first light among the light emitted from the light emitting element 1 is almost totally reflected at the reflecting surface 7 that forms the interface between the optical member 9 and air. Further, the light is refracted by the second exit surface 8 to become light substantially parallel to the irradiation optical axis AXL, and exits from the second exit surface 8.

  At this time, the inner peripheral end portion of the second exit surface 8 that is close to the boundary with the lens surface 6 is the largest of the second light totally reflected by the reflection surface 7 with respect to the exit optical axis AXL. A light ray emitted from the light emitting element 1 is incident at an angle. In addition, a light ray having the largest angle with respect to the irradiation optical axis AXL is incident on the outer peripheral end portion of the lens surface 6 near the boundary with the second exit surface 8. Accordingly, light is emitted from the entire emission portion (lens surface 6 and second emission surface 8) of the optical member 9. That is, there is no region where light is not emitted as indicated by reference numeral 70 in FIG.

  For this reason, when the light emitting device shown in FIG. 1 is viewed from the front in the emission optical axis direction, there is no uneven light emission in the emission part, and a uniform light emission state is obtained. In addition, since the light emitted from the light emitting element 1 is emitted in a substantially parallel state, the light can be irradiated in a narrow range. That is, high directivity can be given to irradiation light.

  Here, although the case where substantially parallel light is emitted from the light emitting device has been described in this embodiment, the present invention is not limited to such a case. For example, the relationship between the position of the light emitting element 1 and the focal position of the lens surface 6 and the surface shapes of the lens surface 6, the reflecting surface 7 and the second exit surface 8 are appropriately changed to provide various light distribution characteristics and directivities. May be obtained.

  In the present embodiment, the case where the lens surface 6 has a convex lens shape has been described. However, the lens surface 6 may be formed in a shape other than this, for example, a Fresnel lens shape.

  Next, a design example of the light emitting device of this embodiment will be described. Here, the material of the optical member 9 is an epoxy resin. Its refractive index is about 1.55. Further, the diameter of the lens surface 6 is set to 3 mm, and the light emitting element 1 is disposed at the focal position of the lens surface 6.

  Further, the maximum angle formed with respect to the emission optical axis AXL of the light emitted from the light emitting element 1 and refracted by the lens surface 6 and substantially parallel to the irradiation optical axis AXL is set to 45 °. Therefore, the angle formed by the line L connecting the boundary between the second exit surface 8 and the lens surface 6 and the approximate center of the light emitting element 1 with respect to the exit optical axis AXL is 45 °.

  At this time, in order for the light totally reflected by the reflecting surface 7 to be refracted by the second exit surface 8 and become light substantially parallel to the exit optical axis AXL, the light totally reflected by the reflecting surface 7 is emitted light. It must be directed to the second exit surface 8 so as to approach the irradiation optical axis AXL at an angle of about 17.86 ° or less with respect to the axis AXL. Since the refractive index of the material of the optical member 9 is about 1.55, a light beam totally reflected by the reflecting surface 7 and traveling at an angle of about 17.86 ° or less with respect to the emission optical axis AXL is emitted from the light emitting element 1. The light beam is emitted at an angle (emission angle) of about 81 ° or less with respect to the optical axis AXL.

  Therefore, in the present design example, the light beam emitted from the light emitting element 1 at an emission angle of 80 ° is totally reflected by the reflection surface 7 and travels toward the emission surface 8 as a light beam having the largest angle with respect to the emission optical axis AXL. The second light exit surface 8 is designed to be refracted at the inner peripheral end portion and to be emitted as a light beam substantially parallel to the light emission optical axis AXL. In this case, the outer diameter of the second emission surface 8 (that is, the outer diameter of the light emitting device) is about 5.7 mm.

  FIG. 3 shows a light emitting device disclosed in Patent Document 2, in which a light beam having the above design condition, that is, an emission angle of 80 ° from the light emitting element, is totally reflected in the total reflection region and then reflected by the reflecting member. It is designed to be emitted substantially parallel to the irradiation optical axis.

  In FIG. 3, 11 is a light emitting element, 12 is a holding part to which the light emitting element 11 is mounted and die-bonded, 13 is a first lead frame, 14 is a bonding wire connecting the light emitting element 11 and the second lead frame 15, Reference numeral 16 denotes a reflecting member, and 19 denotes an optical member molded by resin so as to seal a part of the light emitting element 11 and the lead frames 13 and 15.

  Reference numeral 17 denotes a direct emission area in which light from the light emitting element 11 is directly incident and emitted from the optical member 19, and 18 denotes a surface formed around the direct emission area 17, from the direct emission area side to the total reflection area. And an exit area where the light reflected by the reflecting member 16 exits after being totally reflected by the total reflection area. The direct emission region 17 is formed in a convex lens shape such as a spherical lens shape, an aspheric lens shape, or a paraboloid shape. Further, the direct emission region 17 is formed to have a size that covers the region 70 where light is not emitted shown in FIG. Reference numeral 20 denotes a recess formed up to a position closer to the irradiation optical axis AXL than the outer periphery of the lens surface of the direct emission region 17.

  Here, when the refractive index of the material of the optical member 19 is 1.55, the outer diameter of the reflecting member 16 (that is, the outer diameter of the light emitting device) is about 6.1 mm. Therefore, under the same design conditions, it can be seen that the diameter of the light emitting device of this example is smaller than the diameter of the light emitting device disclosed in Patent Document 2.

  In the light emitting device disclosed in Patent Document 2, the maximum emission angle from the light emitting element can theoretically be close to 90 °. However, in this case, the depth of the recess 20 becomes too large, so The optical member 19 cannot be manufactured. In addition, since the light emitting element is not actually a point light source but an element having a certain light emitting area, when the concave portion 20 becomes deep, light emitted from the outer peripheral portion of the light emitting element easily enters the concave portion 20, Usage efficiency deteriorates. In the above example, the inner diameter of the recess 20 is about 1.1 mm.

  FIG. 4 shows a cross section when the light emitting device according to the second embodiment of the present invention is cut along a plane including the emission optical axis AXL. In Example 1, since the light beam emitted from the light emitting element at an emission angle of approximately 90 ° is incident on the reflection surface 7 at an incident angle smaller than the total reflection critical angle, it is not totally reflected and is emitted from the reflection surface 7. End up. In this embodiment, in order to effectively use such light rays, light that cannot be totally reflected by the reflecting surface 7 of Embodiment 1, that is, a large incident angle smaller than the total reflection critical angle with respect to the reflecting surface. A reflection member is provided that reflects the light emitted from the light emitting element at the emission angle toward the second emission surface. In FIG. 4, a ray tracing diagram is also shown.

  In FIG. 4, 21 is a light emitting element such as an LED or LD, 23 is a first lead frame having a holding portion 22 that is die-bonded with the light emitting element 21 mounted, and 24 is a light emitting element 21 and a second lead frame 25. Bonding wire that connects

  Reference numeral 29 denotes an optical member molded with an optical resin material so as to seal the light emitting element 21 and the portions of the lead frames 23 and 25 on the light emitting element 21 side. The optical resin material is preferably a heat resistant material such as epoxy resin or silicon.

  In the optical member 29, reference numeral 26 denotes a lens surface as a first exit surface that has a positive refractive power with respect to incident light from the light emitting element 21 and is formed so that the irradiation optical axis AXL passes through the center thereof. The lens surface 26 is formed in a convex lens shape such as a spherical lens shape, an aspheric lens shape, and a paraboloid shape. Of the light emitted from the light emitting element 21, light having an angle θ1 smaller than the first predetermined angle with respect to the irradiation optical axis AXL (hereinafter referred to as first light) is directly incident on the lens surface 26. And it is ejected while being condensed. Reference numeral 27 denotes light emitted from the light emitting element 21 and having an angle θ2 that is not less than a first predetermined angle and not more than a second predetermined angle with respect to the irradiation optical axis AXL (hereinafter referred to as second light). This is a reflection surface (internal reflection surface) that totally reflects this.

  Reference numeral 28 denotes a second emission surface on which the light totally reflected by the reflection surface 27 is incident, refracted and emitted forward (in the irradiation optical axis direction, that is, the right side in FIG. 4). Here, as shown in FIG. 4, the second emission surface 28 is formed as a surface having a truncated cone shape including a line L that is inclined with respect to the irradiation optical axis AXL from the approximate center of the light emitting element 21. Yes. In other words, the light emitting element 21 in the irradiation optical axis direction of the second emission surface 28 is a portion (outer peripheral portion) farthest from the irradiation optical axis AXL than a portion (inner peripheral portion) closest to the irradiation optical axis AXL. It has a shape protruding in the opposite direction (irradiation direction). The inner periphery of the second exit surface 28 is in contact with the outer periphery of the lens surface 26.

  Reference numeral 30 denotes light that cannot be totally reflected by the reflecting surface 27, that is, light emitted from the light emitting element 21 at an angle θ3 larger than the second predetermined angle with respect to the irradiation optical axis AXL (hereinafter referred to as third light). It is a reflecting member that leads to the exit surface 28. The reflecting member 30 is formed of a metallic material such as bright aluminum whose inner surface has a high reflectance.

  In the light emitting device of this embodiment, the first light having a small angle with respect to the irradiation optical axis AXL among the light emitted from the light emitting element 21 is disposed at the focal point of the lens surface 26 or in the vicinity thereof. The light is refracted by the lens surface 26 that forms the interface between the optical member 29 and air, and is emitted from the lens surface 26 as light substantially parallel to the irradiation optical axis AXL. In addition, the second light whose angle with respect to the irradiation optical axis AXL is larger than the first light among the light emitted from the light emitting element 21 is almost totally reflected at the reflection surface 27 that forms the interface between the optical member 29 and the air. Further, the light is refracted by the second exit surface 28 to become light substantially parallel to the irradiation optical axis AXL, and exits from the second exit surface 28.

  Further, of the light emitted from the light emitting element 21, the third light whose angle with respect to the irradiation optical axis AXL is larger than the second light is reflected by the reflecting member 30 and guided to the second emission surface 28. The light is refracted by the second exit surface 28 and becomes substantially parallel to the irradiation optical axis AXL, and exits from the second exit surface 28.

  At this time, the largest angle with respect to the emission optical axis AXL among the third light reflected by the reflecting member 30 at the inner peripheral end portion of the second emission surface 28 close to the boundary with the lens surface 26. The light emitted from the light emitting element 21 enters. In addition, a light ray having the largest angle with respect to the irradiation optical axis AXL is incident on the outer peripheral end portion of the lens surface 26 that is close to the boundary with the second exit surface 28. Further, among the third light, the light beam emitted from the light emitting element 21 at the smallest angle with respect to the emission optical axis AXL and reflected by the reflecting member 30, and the second light with respect to the emission optical axis AXL most. The incident positions of the light beams emitted from the light emitting element 21 at a large angle and reflected by the reflecting surface 27 on the second exit surface 28 are close to each other.

  As a result, light is emitted from the entire emission portion (lens surface 26 and second emission surface 28) of the optical member 29. That is, there is no region where light is not emitted as indicated by reference numeral 70 in FIG.

  For this reason, when the light emitting device shown in FIG. 4 is viewed from the front in the emission optical axis direction, there is no light emission unevenness in the emission part, and a uniform light emission state is obtained. In addition, since the light emitted from the light emitting element 21 is emitted substantially in parallel, the light can be irradiated in a narrow range. That is, high directivity can be given to irradiation light.

  Here, although the case where substantially parallel light is emitted from the light emitting device has been described in this embodiment, the present invention is not limited to such a case. For example, the relationship between the position of the light emitting element 21 and the focal position of the lens surface 26, and the surface shapes of the lens surface 26, the reflecting surface 27, the reflecting member 30, and the second exit surface 28 are appropriately changed to provide various light distributions. You may make it acquire a characteristic and directivity.

  In the present embodiment, the case where the lens surface 26 has a convex lens shape has been described. However, the lens surface 26 may be formed in a shape other than this, for example, a Fresnel lens shape.

  FIG. 5 shows a cross section when the light receiving device according to the third embodiment of the present invention is cut along a plane including the incident optical axis AXL. FIG. 5 also shows a ray tracing diagram.

  In FIG. 5, 31 is a light receiving element such as a photodiode or a photoelectric conversion element, 33 is a first lead frame having a holding portion 32 that is die-bonded in a state where the light receiving element 31 is mounted, and 34 is a light receiving element 31 and a second light receiving element. A bonding wire that connects the lead frames 35.

  Reference numeral 39 denotes an optical member molded with an optical resin material so as to seal the light receiving element 31 and the portions of the lead frames 33 and 35 on the light receiving element 31 side. As the optical resin material, epoxy resin, silicon or the like is preferable.

  In the optical member 39, reference numeral 36 denotes a lens surface as a first incident surface having a positive refractive power with respect to incident light from the outside, which is formed so that the incident optical axis AXL passes through the center. The lens surface 36 is formed in a convex lens shape such as a spherical lens shape, an aspheric lens shape, and a paraboloid shape. Light incident on the lens surface 36 from the outside (light substantially parallel to the incident optical axis AXL) is condensed on the light receiving element 31 by a positive refractive power.

  Reference numeral 38 denotes a second incident surface formed around the lens surface 36. Here, as shown in FIG. 5, the second incident surface 38 is formed as a surface having a truncated cone shape including a line L extending obliquely from the approximate center of the light receiving element 31 with respect to the incident optical axis AXL. Yes. In other words, the light receiving element 31 in the direction of the incident optical axis of the second incident surface 38 is a portion (outer peripheral portion) farthest from the incident optical axis AXL than a portion (inner peripheral portion) closest to the irradiation optical axis AXL. It has a shape protruding in the opposite direction (light emitting source direction). Further, the inner periphery of the second incident surface 38 is in contact with the outer periphery of the lens surface 36.

  Reference numeral 37 denotes a reflecting surface (inner surface reflecting surface) that totally reflects and collects the light incident into the optical member 39 from the second incident surface 38 toward the light receiving element 31.

  According to the light receiving device of the present embodiment, the light incident on the lens surface 36 from the front (right side in the drawing) is disposed at the focal position of the lens surface 36 or in the vicinity thereof. It is efficiently collected on top. Then, the light incident on the lens surface 36 and the light incident on the second incident surface 38 in contact therewith, that is, the light incident on almost the entire incident portion of the optical member 39 can be guided to the light receiving element 31. Therefore, the incident portion of the optical member 39 does not cause the disadvantage that the light incident on the total reflection region of the surface on which light from the outside is incident cannot be guided to the light receiving element as in the light receiving device shown in FIG. Can be received by the light receiving element 31 without waste.

  Here, if a light receiving element such as a photodiode or a photoelectric conversion element is used for sensing, for example, the sensitivity is improved by increasing the amount of received light. In the photoelectric conversion element, the electric energy generated by the increase in the amount of received light increases. Therefore, in these light receiving elements, it is desired to increase the light receiving area as much as possible. However, when the light receiving area of the light receiving element is increased, the number of light receiving element chips obtained from one single crystal wafer is reduced, leading to an increase in cost. There is also a method in which a lens is arranged in front of the light receiving element and the light incident on the lens is collected on the light receiving element. However, this method requires a large lens, and the distance between the light receiving element and the lens is large. Since the thickness in the direction of the incident optical axis increases by the amount, the entire light receiving device is increased in size.

  On the other hand, if the light receiving device of this embodiment is used, the light incident in the vicinity of the incident optical axis AXL is condensed on the light receiving element 31 by the lens surface 36, and the light incident on the position away from the incident optical axis AXL is converted. Since the light is condensed on the light receiving element 31 by the refracting action of the second incident surface 38 and the total reflecting action of the reflecting face 37, without increasing the light receiving area of the light receiving element 31 or increasing the size of the light emitting device, A sufficient amount of received light can be obtained by efficiently guiding the light from the incident portion to the light receiving element 31.

  FIG. 6 shows a cross section of the light receiving device that is Embodiment 4 of the present invention cut along a plane including the incident optical axis AXL. FIG. 6 also shows a ray tracing diagram.

  In FIG. 6, reference numeral 41 denotes a light receiving element such as a photodiode or a photoelectric conversion element, 43 denotes a first lead frame having a holding portion 42 which is die-bonded in a state where the light receiving element 41 is mounted, and 44 denotes a light receiving element 41 and a second light receiving element. A bonding wire that connects the lead frames 45.

  Reference numeral 49 denotes an optical member molded with an optical resin material so as to seal the light receiving element 41 and the portions of the lead frames 43 and 45 on the light receiving element 41 side. As the optical resin material, epoxy resin, silicon or the like is preferable.

  In the optical member 49, reference numeral 46 denotes a lens surface as a first incident surface having a positive refractive power with respect to incident light from the outside, which is formed so that the incident optical axis AXL passes through the center. The lens surface 46 is formed in a convex lens shape such as a spherical lens shape, an aspheric lens shape, or a paraboloid shape. Light incident on the lens surface 46 from the outside (light substantially parallel to the incident optical axis AXL) is collected on the light receiving element 41 by a positive refractive power.

  Reference numeral 48 denotes a second incident surface formed around the lens surface 46. Here, as shown in FIG. 6, the second incident surface 48 is formed as a surface having a truncated cone shape including a line L extending obliquely from the approximate center of the light receiving element 41 with respect to the incident optical axis AXL. Yes. In other words, the second incident surface 48 has a light receiving element 41 in the direction of the incident optical axis where the portion (outer peripheral portion) farthest from the incident optical axis AXL is closer than the portion (inner peripheral portion) closest to the irradiation optical axis AXL. It has a shape protruding in the opposite direction (light emitting source direction). The inner periphery of the second incident surface 48 is in contact with the outer periphery of the lens surface 46.

  Reference numeral 47 denotes a reflecting surface (inner surface reflecting surface) that totally reflects and collects the light incident into the optical member 49 from the second incident surface 48 toward the light receiving element 41.

  Further, 50 reflects the light incident on the reflection surface 47 at an angle smaller than the total reflection critical angle from the second incident surface 48 into the optical member 49 toward the light receiving element 41 and collects the light. It is a reflective member that shines.

  According to the light receiving device of the present embodiment, the light incident on the lens surface 46 from the front (right side in the drawing) is disposed at the focal position of the lens surface 46 or in the vicinity thereof. It is efficiently collected on top. The light incident on the lens surface 46 and the light incident on the second incident surface 48 in contact therewith, that is, the light incident on almost the entire incident portion of the optical member 49 can be guided to the light receiving element 41. Therefore, similarly to the third embodiment, the light incident on the incident portion of the optical member 49 can be received by the light receiving element 41 without waste.

  Furthermore, the light incident near the incident optical axis AXL is condensed on the light receiving element 41 by the lens surface 46, and the light incident on the position away from the incident optical axis AXL is refracted by the second incident surface 48. Since the light is condensed on the light receiving element 41 by the total reflection action of the reflection surface 47 and the reflection action of the reflection member 50, the light receiving area of the light receiving element 41 is not increased and the light emitting device is not enlarged. Can be efficiently guided to the light receiving element 41 to obtain a sufficient amount of received light.

  In each of the above-described embodiments, the case where the light emitting element or the light receiving element is sealed with the optical member that is a mold resin has been described. However, the present invention is only in the case where the light emitting element or the light receiving element and the optical member are integrated as described above. In addition, the present invention can be applied to a case where a light emitting element or a light receiving element is disposed outside the optical member.

  FIG. 7 shows a cross section of the light receiving device that is Embodiment 5 of the present invention cut along a plane including the incident optical axis AXL. FIG. 7 also shows a ray tracing diagram. In this example, an example in which an optical member having the same optical action as that of the optical member of Example 1 is arranged in front of a surface-mount type light emitting element will be described.

  In FIG. 7, reference numeral 51 denotes a light emitting element such as a surface mount type LED or LD. Reference numeral 59 denotes an optical member made of an optical resin material. The optical resin material is preferably a heat resistant material such as epoxy resin or silicon.

  In the optical member 59, reference numeral 60 denotes an incident surface formed so that the irradiation optical axis AXL passes through the center thereof, and the light emitted from the light emitting element 51 enters. The incident surface 60 has a spherical shape with the approximate center of the light emitting element 51 as the center.

  Reference numeral 56 denotes a lens surface as a first exit surface that has a positive refractive power with respect to incident light from the light emitting element 51 and is formed so that the irradiation optical axis AXL passes through the center. The lens surface 56 is formed in a convex lens shape such as a spherical lens shape, an aspheric lens shape, and a paraboloid shape. On the lens surface 56, light emitted from the light emitting element 51 and entering the optical member 59 from the incident surface 60 and having an angle θ1 smaller than a predetermined angle with respect to the irradiation optical axis AXL (hereinafter referred to as a first lens). Light) is directly incident and emitted while being collected. Reference numeral 57 denotes a light emitted from the light emitting element 51, and light (which will be referred to as second light hereinafter) having an angle θ <b> 2 greater than or equal to a predetermined angle with respect to the irradiation optical axis AXL among the light incident from the incident surface 60 into the optical member 59. And this is a reflection surface (internal reflection surface) that totally reflects this.

  Reference numeral 58 denotes a second emission surface on which the light totally reflected by the reflection surface 57 is incident, refracted and emitted forward (in the irradiation optical axis direction, that is, the right side in FIG. 7). Here, as shown in FIG. 7, the second emission surface 58 is formed as a surface having a truncated cone shape including a line L that is inclined from the approximate center of the light emitting element 51 and extends with respect to the irradiation optical axis AXL. Yes. In other words, the light emitting element 51 in the irradiation optical axis direction of the second emission surface 58 is a portion (outer peripheral portion) farthest from the irradiation optical axis AXL than a portion (inner peripheral portion) closest to the irradiation optical axis AXL. It has a shape protruding in the opposite direction (irradiation direction). The inner periphery of the second exit surface 58 is in contact with the outer periphery of the lens surface 56.

  In the light emitting device of this embodiment, the first light having a small angle with respect to the irradiation optical axis AXL among the light emitted from the light emitting element 51 is disposed at the focal point of the lens surface 56 or in the vicinity thereof. The light is refracted by the lens surface 56 that forms the interface between the optical member 59 and air, and is emitted from the lens surface 56 as light substantially parallel to the irradiation optical axis AXL. In addition, the second light whose angle with respect to the irradiation optical axis AXL is larger than the first light among the light emitted from the light emitting element 51 is almost totally reflected by the reflection surface 57 that forms the interface between the optical member 59 and the air. Further, the light is refracted by the second exit surface 58 to become light substantially parallel to the irradiation optical axis AXL, and exits from the second exit surface 58.

  At this time, at the inner peripheral end portion of the second exit surface 58 close to the boundary with the lens surface 56, the second light totally reflected by the reflection surface 57 is the largest with respect to the exit optical axis AXL. A light beam emitted from the light emitting element 51 is incident at an angle. In addition, a light ray having the largest angle with respect to the irradiation optical axis AXL is incident on the outer peripheral end portion of the lens surface 56 that is close to the boundary with the second emission surface 58. As a result, light is emitted from the entire emission portion (lens surface 56 and second emission surface 58) of the optical member 59. That is, there is no region where light is not emitted as indicated by reference numeral 70 in FIG.

  For this reason, when the light emitting device shown in FIG. 7 is viewed from the front in the emission optical axis direction, there is no light emission unevenness in the emission part, and a uniform light emission state is obtained. In addition, since the light emitted from the light emitting element 51 is emitted in a substantially parallel state, the light can be irradiated in a narrow range. That is, high directivity can be given to irradiation light.

  Here, although the case where substantially parallel light is emitted from the light emitting device has been described in this embodiment, the present invention is not limited to such a case. For example, the relationship between the position of the light emitting element 51 and the focal position of the lens surface 56, and the surface shapes of the lens surface 56, the reflecting surface 57, and the second exit surface 58 are appropriately changed to provide various light distribution characteristics and directivities. May be obtained.

  In the present embodiment, the case where the lens surface 56 has a convex lens shape has been described. However, the lens surface 56 may have a shape other than this, for example, a Fresnel lens shape. Furthermore, the incident surface 60 may have a convex lens shape or a Fresnel lens shape.

  In addition, although the present Example demonstrated the case where the light emitted from the surface mount type light emitting element was guide | induced to an irradiation direction only with the optical member which has a lens surface and a reflective surface, surface mount type like Example 2 The light emitted from the light emitting element may be guided in the irradiation direction by an optical member having a lens surface and a reflecting surface and a reflecting member provided separately from the light emitting element.

  Various light emitting elements such as a shell type light emitting device, a bare chip type light emitting device, a heat radiation type light emitting device, and a flat package type light emitting device can be used.

    Furthermore, the dimensions, materials, shapes, arrangement relationships, and the like of the components described in the embodiments described above are merely examples, and do not limit the present invention. For example, in each of the embodiments described above, the case where the second exit surface and the second entrance surface are formed in a planar shape has been described, but these may be formed in a curved surface shape (spherical shape, aspherical shape, etc.). .

  FIG. 8A and FIG. 8B show specific examples of devices provided with the light-emitting device and the light-receiving device described in the above embodiments, respectively.

  FIG. 8A shows a device 200 in which a plurality of light emitting devices 100 shown in Examples 1, 2, and 5 are arranged in a matrix. This device 200 is suitable as a display unit, a vehicle lamp unit, or the like because the individual light emitting devices 100 are small in size, emit light uniformly when viewed from the irradiation optical axis direction, and have higher directivity.

  FIG. 8B shows a device 400 in which a plurality of light receiving devices 300 shown in the third and fourth embodiments are arranged. This device 400 is suitable as a photoelectric sensor unit, a solar cell unit, or the like because a large amount of received light can be obtained even though each light receiving device 300 is small.

1 is an external perspective view of a light emitting device that is Embodiment 1 of the present invention. FIG. FIG. 3 is a cross-sectional view of the light emitting device of Example 1. Sectional drawing of the conventional light-emitting device. Sectional drawing of the light-emitting device which is Example 2 of this invention. Sectional drawing of the light-receiving device which is Example 3 of this invention. Sectional drawing of the light-receiving device which is Example 4 of this invention. Sectional drawing of the light-emitting device which is Example 5 of this invention. The external view of the apparatus provided with the light-emitting device of each Example. The external view of the apparatus provided with the light-receiving device of each Example. Sectional drawing of the conventional light-emitting device or light-receiving device. Sectional drawing of the conventional light-emitting device or light-receiving device.

Explanation of symbols

1, 21, 51 Light-emitting element 6, 26, 36, 46, 56 Lens surface (first exit surface or first entrance surface)
7, 27, 37, 47, 57 Reflective surface 8, 28, 58 Second exit surface 9, 29, 39, 49, 59 Optical member 30, 50 Reflective member 60 Incident surface 31, 41 Light receiving element

Claims (11)

A light emitting element;
A first emission surface for emitting light emitted from the light emitting element at an angle smaller than a predetermined angle with respect to the irradiation optical axis, and emitted from the light emitting element at an angle larger than the predetermined angle with respect to the irradiation optical axis A reflection surface that reflects light, and an optical member that is formed around the first emission surface and has a second emission surface that emits light reflected by the reflection surface;
The second emission surface has a shape in which a portion farthest from the irradiation optical axis protrudes in a direction opposite to the light emitting element in the irradiation optical axis direction than a portion closest to the irradiation optical axis. A light emitting device.   2. The light emitting device according to claim 1, wherein the second emission surface has a surface shape including a line extending obliquely with respect to the irradiation optical axis from a substantial center of the light emitting element.   The light emitting device according to claim 1, wherein the second emission surface is in contact with the first emission surface.   The light emitting device includes a reflecting member that reflects light emitted from the light emitting element toward the second emitting surface at a larger angle with respect to the irradiation optical axis than light that is totally reflected by the reflecting surface. Item 4. The light emitting device according to any one of Items 1 to 3.   The light-emitting device according to claim 1, wherein the light-emitting element is disposed inside the optical member. A light receiving element;
A first incident surface formed so as to pass an incident optical axis and directing incident light to the light receiving element; a second incident surface formed around the first incident surface; and the second incident surface An optical member having a reflective surface that reflects light incident from the surface toward the light receiving element;
The second incident surface has a shape in which a portion farthest from the incident optical axis protrudes in a direction opposite to the light receiving element in the incident optical axis direction than a portion closest to the incident optical axis. The light receiving device.   The light receiving device according to claim 6, wherein the second incident surface has a surface shape including a line extending obliquely from the approximate center of the light receiving element with respect to the incident optical axis.   The light receiving device according to claim 6, wherein the second incident surface is in contact with the first incident surface.   9. The reflecting member according to claim 6, further comprising a reflecting member that reflects light that is not totally reflected by the reflecting surface out of light from the second incident surface toward the light receiving element. Light receiving device.   The light receiving device according to any one of claims 6 to 9, wherein the light receiving element is disposed inside the optical member. An apparatus comprising at least one of the light emitting device according to any one of claims 1 to 5 and the light receiving device according to any one of claims 6 to 10.