权利要求:
1. A light emitting device comprising:
a plurality of light source parts each being configured to emit an irradiation light, the plurality of light source parts comprising at least one first light source part, at least one second light source part, and at least one third light source part; wherein
each of the at least one first light source part comprising a first light emitting element having a first light emitting surface and a first light-guiding member configured to guide light emitted from the first light emitting element;
each of the at least one second light source part comprising a second light emitting element having a second light emitting surface and a second light-guiding member configured to guide light emitted from the second light emitting element;
each of the least one third light source part comprising a third light emitting element having a third light emitting surface and a third light-guiding member configured to guide light emitted from the third light emitting element;
with respect to at least one second light source part, a center of a light-exiting surface of the second light-guiding member is positionally shifted from a center of an incident surface of the second light-guiding member;
each of the at least one first light-guiding member having a tapered shape narrowing toward the first light emitting element; and
each of the at least one second light-guiding member having a tapered shape narrowing toward the second light emitting element;
wherein the irradiation light emitted from the first light source part and the irradiation light emitted from the second light source part satisfy the condition (1):
θ≤α≤tan−1{2 tan(θ)} (1)
wherein θ is an angle between an imaginary straight line connecting a position of center of a light-irradiation region on a light-irradiation surface of the irradiation light emitted from each one of the at least one first light source part and a center of the first light emitting surface of the first light source part, the light-irradiation surface being separate and spaced apart from the light emitting device, and the light-irradiation surface being a flat plane surface perpendicular to a first central axis of the first light-guiding member, and
an imaginary straight line connecting a position on the light-irradiation surface having an illuminance of at least one-half of an illuminance at center position of the corresponding one of the at least one first light source part and the center of the first light emitting surface of the first light source part, and
α is an angle between the imaginary straight line connecting the position of center of the light-irradiation region on the light-irradiation surface of the irradiation light emitted from the corresponding one of the at least one first light source part and the center of the first light emitting surface of the corresponding one of the at least one first light source part, and
an imaginary straight line connecting a position of center of a light-irradiation region on a light-irradiation surface of the irradiation light emitted from each one of the at least one second light source part and a center of the second light emitting surface of the second light source part,
wherein the second light emitting element of one of the at least one second light source part is positioned on a boundary of the corresponding second light-exiting surface of the corresponding second light-guiding member when viewed in a plan view, and
the third light emitting element of the at least one third light source part that is adjacent to the at least one second light source part, is positioned on a boundary of the corresponding third light-exiting surface of the corresponding third light-guiding member when viewed in the plan view.
2. The light emitting device according to claim 1, further comprising a control part for controlling irradiation of light emitted from the plurality of light source parts.
3. The light emitting device according to claim 1, wherein a first central axis of the first light-guiding member is inclined with respect to a second central axis of the second light-guiding member.
4. The light emitting device according to claim 1, wherein the plurality of light source parts further comprises at least one third light source part, the at least one first light source part and the at least one second light source part are configured to emit light with a first divergence angle, and the at least one third light source part is configured to emit light with a second divergence angle that is different from the first divergence angle.
5. The light emitting device according to claim 1, wherein the at least one first light-guiding member or the at least one second light-guiding member or both the at least one first light-guiding member and the at least one second light-guiding member is made of a resin containing light dispersing particles.
6. The light emitting device according to claim 1, wherein
each of the plurality of light source parts includes a plurality of lateral surfaces, and
the plurality of lateral surfaces of adjacent light source parts are not in contact with each other.
7. The light emitting device according to claim 1, wherein
each of the first light source part and the second light source part comprises a light emitting diode.
8. The light emitting device according to claim 1, further comprising:
a light guide member array including the first light source part and the second light source part.
9. The light emitting device according to claim 2, wherein the control part comprises a determining part to determine a duty ratio of light emission for each of the plurality of light source parts, based on a type of light distribution pattern.
10. The light emitting device according to claim 2, wherein
the control part includes a light distribution information acquisition part, a storage part, a determining part, and an irradiation control part.
11. The light emitting device according to claim 3, wherein a distance between the first central axis and the second central axis at an emission side is greater than at an incident side.
12. The light emitting device according to claim 3, wherein a distance between the first central axis and the second central axis at an incident side is greater than at an emission side.
13. The light emitting device according to claim 4, wherein an angular difference 11 between the first divergence angle and the second divergence angle satisfies a condition (2)
η>α (2).
14. The light emitting device according to claim 7, wherein
each light emitting diode of the first light source part and the second light source part is a white light emitting diode or light bulb color light emitting diode.
15. The light emitting device according to claim 8, wherein
the light guide member array comprises a glass material or a resin material.
16. The light emitting device according to claim 8, further comprising:
a light guide holding member configured to hold the light guide member array.
具体实施方式:
[0033]Certain embodiments of the present invention will be described below with reference to the accompanying drawings. In the description below, the same numerals in different drawings indicate the same or similar portions or members.
[0034]The embodiments described below are intended as illustrative of a light emitting device to give a concrete form to technical ideas of the present invention, and the scope of the invention is not limited to those described below. The sizes, materials, shapes and the relative configuration etc. of the components described in embodiments are given as an example and not as a limitation to the scope of the invention unless specifically described otherwise. The sizes and the positional relationships of the members in each of the drawings are occasionally shown exaggerated for ease of explanation.
[0035]The X direction along the X-axis, Y-axis, and Z-axis may indicate the direction in the array plane where the light source parts of the light source part for the embodiment are aligned. The Y direction along the Y-axis indicates the direction perpendicular to the X direction in the array plane, and the Z-axis indicates the direction perpendicular to the alignment plane.
[0036]The direction in which the arrow is oriented in the X direction is indicated as +X (plus X) direction and the direction opposite to the +X direction is indicated as −X (minus X) direction. The direction in which the arrow is oriented in the Y direction is indicated as +Y (plus Y) direction and the direction opposite to the +Y direction is indicated as −Y (minus Y) direction. The direction in which the arrow is oriented in the Z direction is indicated as +Z (plus Z) direction and the direction opposite to the +Z direction is indicated as −Z (minus Z) direction. In the embodiments, a plurality of light source parts are configured to emit light in +Z direction, for example.
Structure of Light Emitting Device 10
[0037]A structure of a light emitting device 10 according to one embodiment will be illustrated below.
Example of Overall Structure
[0038]FIGS. 1A and 1B show an example of the overall configuration of a light emitting device 10 according to one embodiment, where FIG. 1A is a perspective view of the light emitting device 10 taken from the light emitting side of the light emitting device 10, and FIG. 1B is a perspective view of the light emitting device 10 taken from the opposite side of the light emitting side of the light emitting device 10.
[0039]The light emitting device 10 is a device is configured to provide light distribution for space rendering, in the form of downlighting, spotlights, etc. to the walls, floor surfaces, etc., in a store/facility, or signboards etc., provided at a store/facility. As shown in FIGS. 1A and 1B, the light emitting device 10 includes a light distribution module 1 having a cylindrical shape and a control part 2 to control the distribution of light from the light distribution module 1 having a cylindrical shape.
[0040]As described later below, the term “light-irradiation surface” in the present specification refers to a surface that is a subject to be irradiated with light emitted from the light emitting device. The term “light-irradiation region” refers to a region within a light-irradiation surface, in more detail, to a region to be irradiated with an illuminance of at least one-half of an illuminance at center position. The term “illuminance at center position” refers to an illuminance at a “position of center of light-irradiation region” which refers to a position at substantially the center of a light-irradiation region (centroid).
[0041]The light distribution module 1 is a module that is installed on the ceiling or wall etc., of a store/facility to provide light distribution. In the present specification, the term “light distribution” refers to a spatial distribution of an illuminance of light emitted from the light emitting device 10. Space rendering using light distribution can be performed by making the light distributed to the walls and floors visible to users of a store/facility, etc.
[0042]As shown in FIG. 1A, the light distribution module 1 has a structure in which an opening 100 to allow light to pass through is formed in a surface at the +Z direction side, such that light emitted inside the light distribution module 1 is directed through the opening 100 and then irradiated in the +Z direction. The light distribution module 1 is configured to be mounted on the ceiling or wall of a store/facility, with its back-side surface in the −Z direction or with its cylindrical part as a portion to be secured.
[0043]The control part 2 is a device configured to control irradiation of light from a plurality of light source parts. The control part 2 is electrically connected to the light distribution module 1 and outputs control signals so as to control light distribution of the light distribution module 1. The control part 2 outputs control signals in response to operations by the manager of the store/facility or the operator installing the light emitting device 10. Alternatively, the control part can output control signals in conjunction with other light emitting devices and/or external devices such as personal computers (Pcs).
[0044]FIG. 2 is an exploded perspective view of a light distribution module 1 of the light emitting device 10. As shown in FIG. 2, the light distribution module 1 includes a back-side member 11, a light emitting diode (LED) substrate 12, a spacer 13, a light guide holding member 14, and an array of light guide members 15, which are assembled along the Z direction and secured with fixing screws 16 to form the light distribution module 1.
[0045]The back-side member 11 is a disk-shaped member that forms a back surface part of the light distribution module 1. The material of the back-side member 11 can be appropriately selected, but the back-side member 11 serves as a base of the light distribution module 1, such that the back-side member 11 is preferably made of a material having a high rigidity, and also in order to stably secure the light emitting device 10 on the ceiling or wall, a lightweight material is preferably employed. Further, the back-side member 11 serves to disperse heat generated by the LEDs 120 and transferred through the LED substrate 12. Therefore, the back-side member 11 is preferably made of a material having high thermal conductivity such as a metal. For example, the back-side member 11 is preferably made of an aluminum alloy and using die-casting technology.
[0046]The LED substrate 12 is a disc-shaped printed substrate on which a plurality of arrays of a plurality of LEDs 120 are mounted. The surface of the LED substrate 12 in the +Z direction is used for the mounting surface 125, and the plurality of LEDs 120 are mounted on the mounting surface 125. For the LED substrate 12, for example, a metal-base (for example, aluminum or copper) two-layer printed substrate can be used.
[0047]The spacer 13 is a disk-shaped member used to maintain spacing in Z direction between the LEDs 120 on the LED substrate 12 and the light guide member array 15 at a predetermined distance. The spacer 13 is secured in a state in which a flat portion of the LED substrate 12 and a flat portion of the spacer 13 are in contact with each other. The spacer 13 is formed with a plurality of through holes at positions in conformity to the plurality of LEDs 120, such that the flat portion of the spacer 13 and the flat portion of the LED substrate 12 are bring in contact with each other, and light emitted from each of the plurality of LEDs 120 is allowed to pass through a corresponding one of the plurality of through-holes.
[0048]A region of a surface of the spacer 13 at one side (surface at −Z direction side etc.) where the through holes are not formed is brought in contact with the LED substrate 12, and a region of a surface of the spacer 13 at the other side (surface at +Z direction side etc.) where the through holes are not formed is brought in contact with the light guide holding member 14 such that the LED substrate 12 and the spacer 13, and the spacer 13 and the light guide holding member 14 are held in place, respectively. This arrangement ensures that the spacing in the Z direction between the light guide member array 15 held by the light guide holding member 14 and the LEDs 120 is maintained at a predetermined distance in the through-hole region.
[0049]The spacer 13 is also provided with a plurality of positioning pins 131 at plurality of respective positions within the flat portion of the spacer 13. Fitting those positioning pins 131 into the positioning holes formed in the light guide holding member 14 allows aligning of the light guide member array 15 held by the light guide holding member 14 and the LEDs 120 within the XY plane.
[0050]The material of the spacer 13 can be appropriately selected, but it is preferable to use a material having a sufficient strength that can prevent or reduce time-depending changes in the spacing distance, and also having high heat-dissipating property to the heat generated by the LED substrate 12. For example, a metal material such as aluminum can be suitably employed.
[0051]The light guide holding member 14 is a cylindrical member configured to hold the light guide member array 15. One side of the light guide holding member 14 (surface in the +Z direction, etc.) is formed with a plurality of narrow-angle through-holes 141 and a plurality of wide-angle through holes 142 for engaging and holding the plurality of light guide member arrays 15.
[0052]The narrow-angle through-holes 141 are adapted for engagingly receiving and securing the narrow-angle light guide member arrays 151 among the light guide member arrays 15, which will be described below. Twelve narrow-angle through-holes 141 are formed corresponding to the number of the narrow-angle light guide member arrays 151.
[0053]The wide-angle through-holes 142 are adapted for engagingly receiving and securing the wide-angle light guide member arrays 152 among the light guide member arrays 15, which will be described below. Four wide-angle through-holes 142 are formed corresponding to the number of the wide-angle light guide member arrays 152.
[0054]The light guide holding member 14 holds the light guide member array 15, in which the narrow-angle light guide member arrays 151 are secured in respective narrow-angle through-holes 141 by using an adhesive, and wide-angle light guide holding members 152 are secured in respective wide-angle through-holes 142 by using an adhesive. For such securing, other than by adhesion, an appropriate securing technique such as press-bonding may be employed.
[0055]The material of the light guide holding member 14 can be appropriately selected, but a material having high rigidity is preferable to stably hold the light guide member array 15, and a lightweight material is preferable to stably securing the light emitting device 10 to the ceiling or wall. For example, the light guide holding member 14 is preferably made of an aluminum alloy and using die-casting technology.
[0056]Light emitted by LEDs 120 corresponding to the narrow-angle light guide member arrays 151 enter the narrow-angle light guide member arrays 151 through the narrow-angle through-holes 141 and exit from the narrow-angle light guide member arrays 151, respectively. Light emitted by LEDs 120 corresponding to the wide-angle light guide member arrays 152 enter the wide-angle light guide member arrays 152 through the wide-angle through-holes 142 and exit from the wide-angle light guide member arrays 152, respectively.
[0057]Regions of the light guide holding member 14 other than the regions defining the narrow-angle through-holes 141 and the wide-angle through holes 142 do not allow light emitted from the LEDs 120 to pass through. For this reason, the regions defining the narrow-angle through-holes 141 and the wide-angle through-holes 142 on the surface of the light guide holding member 14 in the +Z direction serve as openings 100 (see FIG. 1A), which allows light to pass through only the predetermined regions.
[0058]The light guide member array 15 is an optical member including a plurality of light guide members each configured to direct light emitted by a corresponding one of the plurality of LEDs 120, aligned in a predetermined configuration. The light guide member array 15 is made of a material that is transmissive to the wavelength(s) of light emitted by the LEDs 120. The LEDs 120 are configured to emit light at least in the wavelength range of visible light. Therefore, a material that is transmissive to at least light in the visible wavelength range can be used.
[0059]For the light guide member array 15, for example, a glass material or a resin material can be used. When the light guide member array 15 is manufactured using a resin material and an injection molding technique, it is more preferable in view of cost and productivity. For example, silicone resin can be used as the resin material.
[0060]Further, it is further preferable when the resin that is used to form the light guide member array 15 contain light-scattering particles having a refractive index that is different from that of the resin, scattering of light guided in the light guide member array 15 can be improved, which can reduce uneven brightness in the irradiation light from the light emitting device 10. Examples of such scattering particles includes acrylic crosslinked particles with a particle size in a range of 4 to 5 μm. However, if there is a difference in refractive index with respect to that of the resin that make up the light guide member array 15, any appropriate material can be employed for the light-scattering particles.
[0061]Each of the light guide members included in the light guide member array 15 is formed in a tapered shape gradually narrowing toward the corresponding one of the LEDs 120. In the present specification, the term “tapered shape” refers to a shape of a long and narrow member, in which the diameter, width, or thickness is gradually reduced. Each of the light guide members according to the present embodiment is formed in a tapered shape narrowing toward a corresponding one of the LEDs 120. The direction toward the LED 120 corresponds to the −Z direction in FIG. 2, and each of the light guide members included in the light guide member array 15 is formed in a tapered shape narrowing in the −Z direction in FIG. 2.
[0062]In the present embodiment, when each of the light guide members have a shape narrowing toward a corresponding one of the LEDs 120, the shape will be referred to as a tapered shape, even when the inclinations of lateral surfaces of the light guide member are not symmetrical to the central axis of the light guide member. In the present embodiment, each of the light guide members has a rectangular shape in a cross-section intersecting the central axis of the light guide member, but the cross-sectional shape may be other shape such as a circular shape.
[0063]The light emitted by each of the LEDs 120 enters the light guide material through the incident surface formed on the narrow side of the tapered shape of the light guide member (in the −Z direction, etc.). Then, the light propagates through the interior of the light guide member while repeating total reflection on the lateral surfaces of the light guide member, and then exits the light guide member through the light-exiting surface formed on the thick side of the taper shape of the light guide member (in the +Z direction, etc.). The emitted light corresponds to irradiation light emitted from the light emitting device 10 in the +Z direction. The light emitted from the plurality of light guide members that constitute the light guide member array 15 is synthesized to form a desired light distribution pattern.
[0064]The light guide member array 15 includes the narrow-angle light guide member arrays 151 and the wide-angle light guide member arrays 152. The narrow-angle light guide member array 151 is an optical member including a plurality of narrow-angle light guide members. Each of the light guide members has a taper angle of about 5.7 degrees and a divergence angle of emitted light is about 12.5 degrees. The narrow-angle light guide array 151 includes 12 groups of the narrow-angle light guide members, in which each group includes nine narrow-angle light guide members. The value of the divergence angle corresponds to a half angle at half-maximum. The above can be applied in a similar manner below.
[0065]The wide angle light guide member array 152 is an optical member formed with a plurality of wide-angle light guide members. Each of the wide-angle light guide members has a taper angle of about 1.9 degrees, and divergence angle of light emitted from each of the wide-angle light guide members is about 30 degrees. The wide-angle light guide member array 152 includes four groups of wide-angle light guide members, in which each group includes nine wide-angle light guide members. In the description below, the divergence angle of light emitted from the narrow-angle light guide member array 151 will be referred to as “first divergence angle” and the divergence angle of light emitted from the wide-angle light guide member array 152 will be referred to as “second divergence angle”. The divergence angles of about 12.5 degrees and about 30 degrees are, respectively, examples of a first divergence angle of light emitted from the narrow-angle light guide member array 151 and a second divergence angle of light emitted from the wide-angle light guide array 152.
[0066]In the present embodiment, the light guide member array 15 that includes light guide member arrays having divergence angles of 12.5 degrees and 30 degrees, respectively, is illustrated, but light guide member arrays of different divergence angles may also employed. That is, the light guide member array 15 may include light guide member arrays of divergence angles other than 12.5 degrees and 30 degrees, or may include light guide member arrays of three or more different divergence angles.
[0067]In addition, the term “wide angle” in a wide-angle light guide member array 152 means that the divergence angle of the light emitted is relatively greater compared to that of light emitted from a narrow-angle light guide array 151, and is not limited to the angle commonly referred to as “wide angle”. Similarly, the term “narrow angle” in a narrow-angle light guide member array 151 means that the divergence angle of the light emitted is relatively less compared to that of light emitted from a wide-angle light guide array 152, and is not limited to the angle commonly referred to as “narrow angle”.
[0068]In other words, the divergence angle of the light emitted from the narrow-angle light guide member array 151 is less than the divergence angle of the light emitted from the wide-angle light guide member array 152.
[0069]Further, the taper angle of individual light guide members and the number of the light guide members, and number of groups of light guide members in the narrow-angle light guide member array 151 and the wide-angle light guide array 152 can be appropriately determined according to purpose. The present embodiment also illustrates an example of light propagating through the light guide member by total internal reflection at lateral surfaces of the light guide member, but propagation of light in different manner may also be employed. For example, deflection surfaces such as reflective surfaces can be provided on each of the lateral surfaces of the light guide member, such that light can be deflected at the lateral surfaces of the light guide member and allowed to propagate through the light guide member.
Structure of Light Source Parts 30
[0070]Next, the structure of the light source part 30 of the light emitting device 10 will be described with reference to the FIG. 3A to FIG. 5. For example, the light source part 30 (an example of light source part formed with a plurality of light source parts) includes the narrow-angle light source parts 30a to 30i and wide-angle light source parts 30j. Example of Structure of Narrow-angle Light Source Parts 30a to 30i
[0071]FIGS. 3A to 3C are each schematic diagram showing an example of configuration of a narrow-angle light source part, where FIG. 3A is a plan view of the narrow-angle light source parts 30a to 30i viewed from +Z direction, FIG. 3B is a cross-sectional view seen from the arrow direction of the A-A line of FIG. 3A, and FIG. 3C is a perspective view of the narrow-angle light guide members 151a to 151i. The narrow-angle light source parts 30a to 30i are an example of a group of narrow-angle light source parts, which includes nine narrow-angle light source parts.
[0072]As shown in FIG. 3A, the narrow-angle light source part 30a includes a narrow-angle light guide member 151a and an LED 120a, the narrow-angle light source part 30b includes a narrow-angle light guide member 151b and an LED 120b, and the narrow-angle light source part 30c includes a narrow-angle light guide member 151c and an LED 120c.
[0073]Similarly, the narrow-angle light source part 30d includes a narrow-angle light guide member 151d and an LED 120d, the narrow-angle light source part 30e includes a narrow-angle light guide member 151e and an LED 120e, and the narrow-angle light source part 30f includes a narrow-angle light guide member 151f and an LED 120f.
[0074]The narrow-angle light source part 30g includes a narrow-angle light guide member 151g and an LED 120g, the narrow-angle light source part 30h includes a narrow-angle light guide member 151h and an LED 120h, and the narrow-angle light source part 30i includes a narrow-angle light guide member 151i and an LED 120i.
[0075]In the description below, the narrow-angle light source part 30e will be illustrated as an example of the “first light source part” and the narrow-light source part 30b or the narrow light source part 30f will be illustrated as an example of the “second light source part”. However, any of the narrow-angle light source parts 30a to 30i can be the “first light source part”. Also, any of the narrow-angle light source parts 30a to 30i except the “first light source part” can be the “second light source part”.
[0076]If the narrow-angle light source part 30e is the “first light source part”, the narrow-angle light guide member 151e corresponds to the “first light guide member” and the LED 120e corresponds to the “first light emitting element”. If the narrow-angle light source part 30b is the “second light source part”, the narrow-angle light guide member 151b corresponds to the “second light guide member” and the LED 120b corresponds to the “second light emitting element”. If the narrow-angle light source part 30f is the “second light source part”, the narrow-angle light guide member 151f corresponds to the “second light guide member” and the LED 120f corresponds to the “second light emitting element”.
[0077]FIG. 3A shows the narrow-angle light source parts 30a to 30i viewed from the light-exiting surface side of the narrow-angle light guide members 151a to 151i. Each of the light-exiting surfaces of the narrow-angle light guide members 151a to 151i are formed in a rectangular shape. The narrow-angle light source parts 30a to 30i are arranged in a two-dimensional array on the +Z side of the LED substrate 12, with three in the X direction and three in the Y direction.
[0078]FIG. 3A shows LEDs 120a to 120i arranged in the −Z direction of the narrow-angle guide members 151a to 151i, with the narrow-angle light guide members 151a to 151i in see-through representation. Also in FIG. 3A, the LED substrate 12 is not shown.
[0079]FIG. 3B shows a cross-sectional view of the narrow-angle light source parts 30d, 30e, and 30f, taken along A-A in FIG. 3A. As shown in FIG. 3B, the LEDs 120d, 120e, and 120f are disposed on the mounting surface 125 of the LED substrate 12. The narrow-angle light guide member 151d is disposed facing the LED 120d from the +Z direction side, the narrow-angle light guide member 151e is disposed facing the LED 120e from the +Z direction side, and the narrow-angle light guide member 151f is disposed facing the LED 120f from the +Z direction side.
[0080]The narrow-angle light guide members 151d, 151e, and 151f are formed in tapered shapes narrowing (decreasing in cross sectional areas perpendicular to respective center axes) toward the LEDs 120d, 120e, and 120f, respectively. The taper angles of the tapered shapes of the narrow-axis light guide members 151d, 151e, and 151f are γ, and as described above, the taper angle γ in the present embodiment is about 5.7 degrees.
[0081]The incident surface 151ei of the narrow-angle light guide member 151e is approximately the same size as the LED 120e and is disposed facing the LED 120e. The light-exiting surface 151eo of the narrow-angle light guide member 151e is greater (greater areas) than the incident surface 151ei.
[0082]Similarly, the incident surface of the narrow-angle light guide member 151d is approximately the same size as the LED 120d and is disposed facing the LED 120d. The incident surface of the narrow-angle light guide member 151f is approximately the same size as the LED 120f and is disposed facing the LED 120f. The light-exiting surface of the narrow-angle light guide member 151e is greater than the incident surface, and the light-exiting surface of the narrow-angle light guide member 151f is greater than the incident surface.
[0083]The narrow-angle light guide members 151d, 151e, and 151f are shaped in a way that the central axes of each other are tilted to each other. In more detail, the narrow-angle light guide member 151e is formed with the central axis 151ec is approximately in parallel to a normal line 125v to the mounting surface 125. Meanwhile, the narrow-angle light guide member 151d is formed with the central axis 151dc tilted by an angle −β with respect to the normal line 125v to the mounting surface 125. The narrow-angle light guide member 151f is formed with the central axis 151fc tilted by an angle +β with respect to the normal line 125v to the mounting surface 125.
[0084]Thus, the narrow-angle light guide members 151d, 151e, and 151f are disposed such that their central axes are inclined to one another. Due to the inclination of the central axes, the distance between the central axis 151ec and the central axis 151fc is greater at the light emitting side than at the light incident side. As shown in FIG. 3C, when seen as one whole, the narrow-angle light guide members 151a to 151i have a truncated pyramid shape.
[0085]The narrow-angle light guide members 151a to 151i may be structured such that the lateral surfaces of adjacent narrow-angle light guide members contact each other, or they may not touch each other. However, when the lateral surfaces of adjacent narrow-angle light guide members are in contact with each other, total reflection will not occur, such that a reflection layer is preferably formed on each of the lateral surfaces.
[0086]In the example shown in FIGS. 3A to 3C, the narrow-angle light guide members 151a to 151i do not have reflective layers on the lateral surfaces, and the light propagates within the narrow-angle light guide members 151a to 151i while totally reflected. At the light-exiting surface side of the narrow-angle light guide members 151a to 151i, the lateral surfaces of the adjacent narrow-angle light guide members are close to each other but are not in contact with each other. Meanwhile, at the light incident surface side, spacing between the lateral surfaces of the adjacent narrow-angle light guide members are increased compared to that at the light incident surface side.
[0087]It is preferable that when the lateral surfaces of the adjacent narrow-angle light guide members are configured not to in contact with each other at the light incident surface side, spacing between adjacent LEDs can be increased, and effect of heat between the adjacent LEDs can be reduced.
Example of Configuration of Wide-Angle Light Source Part 30j
[0088]FIGS. 4A to 4D are each schematic diagram showing an example of configuration of a wide-angle light source part 30j, where FIG. 4A is a plan view of the wide-angle light source part 30j viewed from the +Z direction side, FIG. 4B is a cross-sectional view seen from the arrow direction of the B-B line of FIG. 4A, and FIG. 4C is a perspective view of a wide-angle light guide member 152j.
[0089]The wide-angle light source part 30j is an example of a group of wide-angle light source parts, in which a single group includes nine wide-angle light source parts. Because all the nine wide-angle light source parts have a same structure in this implementation, each of the wide-angle light source parts will be referred to as “wide-angle light source part 30j” in the description below.
[0090]As shown in FIG. 4A, the wide-angle light source part 30j includes a wide-angle light guide member 152j and an LED 120j. FIG. 4A shows the wide-angle light source part 30j viewed from the light-exiting surface side of the wide-angle light guide member 152j. The wide-angle light source part 30j corresponds to a third light source part, the LED 120j corresponds to a third light emitting element, and the wide-angle light guide member 152j corresponds to a third light guide component.
[0091]The light-exiting surface of each of the wide-angle light guide members 152j is formed in a rectangular shape. The wide-angle light source parts 30j are arranged in a two-dimensional array shape on the +Z direction side of the LED substrate 12, with three aligned along the X direction and three aligned along the Y direction.
[0092]In FIG. 4A, the LED 120j, which is disposed in the −Z direction of the wide-angle light guide member 152j, is shown with the wide-angle light guide member 152j in see-through configuration. Also in FIG. 4A, the LED substrate 12 is not shown.
[0093]FIG. 4B is a cross-sectional view of the wide-angle light source part 30j seen from the arrow direction of the B-B line of FIG. 4A. As shown in FIG. 4B, the LED 120j is disposed on the mounting surface 125 of the LED substrate 12. The wide-angle light guide member 152j is mounted facing the LED 120j from the +Z direction side.
[0094]The wide-angle light guide member 152j is formed in a tapered shape narrowing toward the LED 120j. The taper angle of the taper shape of the wide-angle light guide member 152j is φ, and as described above, the taper angle φ is about 1.9 degrees. Therefore, the taper angle φ of the wide-angle light guide member 152j is different from the taper angle γ of the narrow-angle light guide members 151d, 151e, and 151f described above.
[0095]The light incident surface 152ji of the wide-angle light guide member 152j is formed approximately the same size as that of the LED 120j and is disposed facing the LED 120j. The light-exiting surface 152jo of the wide-angle light guide member 152j is larger than the light-incident surface 152ji. The nine wide-angle light guides 152j are all formed such that the central axis 152jc is substantially in parallel to the normal line 125v to the mounting surface 125. Example of Configuration of Narrow-angle Light Source Parts 30a to 30i and Wide-angle Light Source Parts 30j.
[0096]FIG. 5 is a schematic plan view illustrating an example of arrangement of narrow-angle light source parts 30a to 30i and wide-angle light source parts 30j in the light emitting device 10.
[0097]FIG. 5 shows the light emitting device 10 viewed from the +Z direction side. Twelve groups of the narrow-angle light source parts, each group 31 including nine narrow-angle light source parts 30a to 30i, are arranged in the XY plane. Also, four groups of wide-angle light source parts, each group 32 including nine wide-angle light source parts 30j, are arranged in the XY plane. The XY plane is a plane parallel to the mounting surface 125 of the LED substrate 12 (see FIG. 2).
[0098]Among the quadrangular regions shown in FIG. 5, the regions demarcated by thin solid lines represent individual narrow-angle light source parts 30a to 30i or individual wide-angle light source parts 30j, while the regions demarcated by thick solid lines represent the groups 31 of the narrow-angle light source parts or the groups 32 of the wide-angle light source parts.
[0099]The LEDs 120 include white LEDs 121 each configured to emit white light, and “light bulb color” LEDs 122 each configures to emit light of