JP7183979B2 - light emitting device - Google Patents

Description

The present invention relates to light emitting devices.

2. Description of the Related Art Conventionally, a light emitting device as a linear light source using a rod-shaped light guide has been known (see, for example, Patent Document 1). The light emitting device described in Patent Document 1 is a vehicle lamp for illuminating the exterior of a vehicle, and is installed along the edge of a front grill on the front surface of the vehicle, for example.

Further, in the light emitting device described in Patent Document 1, a rod-shaped light guide is accommodated inside the connected case and lens. prevent intrusion into the interior of the The case and the lens are connected by engaging claws provided on the lens with engaged portions provided on the case.

JP 2016-4755 A

In the light-emitting device described in Patent Document 1, it is necessary to secure the claw portion of the lens, the engaged portion of the case, and the installation area for the waterproof material. A gap needs to be provided between the case and the light guide for reflection, which increases the width of the light emitting device compared to the width of the light guide. Therefore, it is difficult to install a light emitting device on a member having a small width.

It is also possible to weld the lens and case together, but if this method is used, in order to ensure the safety of the operator, a certain amount of width must be provided around the welded part so that burrs generated by welding do not protrude. It is necessary to establish a department. Also in this case, it is necessary to provide a gap between the case and the light guide in order to secure an air layer. Furthermore, the case and the light guide must have a shape such that the parts other than the welded part do not come into contact with the welding jig. This also increases the width of the light emitting device compared to the width of the light guide.

One of the objects of the present invention is to provide a light emitting device as a linear light source using a rod-shaped light guide, which is waterproof and has a small width.

One embodiment of the present invention provides the following light-emitting devices [1] to [5] in order to achieve the above objects.

[1] A light-emitting element, a light-guiding region for propagating light incident from the light-emitting element to the inside, and a lens formed continuously with the light-guiding region and extracting the light propagating inside the light-guiding region to the outside. a light guide having a region; a first cover covering a part of the surface of the light guide through an air layer; and a remaining surface of the light guide closely connected to the first cover. and a second cover that covers and transmits the light.
[2] The light emitting device according to [1] above, wherein the second cover is welded to the first cover.
[3] The light-emitting device according to [1] or [2] above, wherein the first cover is made of a material different from that of the light guide.
[4] The light-emitting device according to any one of [1] to [3] above, wherein the melting temperature of the second cover is set higher than the melting temperature of the first cover.
[5] Any one of [1] to [4] above, wherein the light guide is rod-shaped, and the light-emitting element is arranged to face the rod-shaped end of the light guide. luminous device.

According to the present invention, it is possible to provide a light emitting device as a linear light source using a rod-shaped light guide, which is waterproof and has a small width.

FIG. 1 is a top view of a light emitting device according to an embodiment of the invention. FIG. 2 is a vertical cross-sectional view of the light-emitting device taken along line AA in FIG. FIG. 3 is a vertical cross-sectional view of the light-emitting device in which FIG. 2 is partially enlarged. FIG. 4 is a cross-sectional view of the light-emitting device taken along line BB in FIG. FIG. 5(a) is a cross-sectional view of a light-emitting device showing a modification of the embodiment shown in FIG. 4, and FIG. 5(b) shows another modification of the embodiment shown in FIG. 1 is a cross-sectional view of a light emitting device shown; FIG. FIG. 6A is an example of a member (design member) to which the light emitting device 1 is attached when the light emitting device 1 is applied to a vehicle, and is a schematic diagram of the front grille 20 of the vehicle. FIG. 6B is a cross-sectional view of the light emitting device 1 installed on the front grille 20. As shown in FIG.

[Embodiment]
(Structure of Light Emitting Device According to Embodiment of the Present Invention)
A light emitting device 1 according to an embodiment of the present invention is a linear light source capable of emitting linear light. Further, since the light emitting device 1 itself has a small width, it can be attached to a member having a small width.

A light-emitting device 1 according to an embodiment of the present invention includes a light-emitting element 14, a light-guiding region 10a through which light 14a incident from the light-emitting element 14 is propagated, and a light-guiding region formed continuously with the light-guiding region 10a. A light guide 10 having a lens region 10b for extracting light 14a propagating inside 10a to the outside, a first cover 11 covering a part of the surface of the light guide 10 via an air layer 18, and a first cover 11. and a second cover 12 that is closely connected to the cover 11 and covers the remaining surface of the light guide 10 to transmit light.

In the above structure, as shown in FIGS. 1 and 2, the light guide 10 is rod-shaped, that is, elongated, and the light-emitting element 14 is arranged to face the rod-shaped end of the light guide 10. .

(Light guide 10)
The light guide 10 has a light guide region 10a and a lens region 10b. The light guide region 10a and the lens region 10b are continuous between both ends of the light guide 10 in the length direction. Taking the central axis CL in the extending direction of the rod shape shown in FIGS. It continues for a predetermined bar-like length in the direction of the central axis CL. That is, the shape of the light guide region 10a and the lens region 10b is also rod-like, and the length direction of the light guide region 10a and the lens region 10b matches or substantially matches the length direction of the light guide 10. FIG.

The rod-shaped "bar" that is the shape of the light guide 10 includes not only a straight bar but also a polygonal bar and a curved bar. It can take a shape according to the shape of the member.

Light 14a emitted from the light emitting element 14 and taken into the light guide 10 through the light intake surface 10c enters the light guide area 10a through the area 10j connecting the light intake surface 10c and the light guide area 10a. , propagate along the length of the light guide region 10a. As shown in FIG. 2, the light intake surface 10c is typically located at one end in the length direction of the light guide 10 at approximately the same height as the light guide region 10a (vertical position in FIG. 2). provided in

The shape of the light guide region 10a is, for example, a cylindrical shape or a prismatic shape (for example, a rectangular parallelepiped). is preferred. When the light guide region 10a is cylindrical, the light reflected in the light guide region 10a passes through the center axis of the light guide region 10a, so the light guide distance is constant, and the change in the light emission intensity of the light emitting device 1 over time is reduced. become smaller. On the other hand, when the light guide region 10a is rectangular, the light reflected in the light guide region 10a does not necessarily pass through the center of the light guide region 10a. Emission intensity tends to increase or decrease over time. Regardless of whether the light guide region 10a has a cylindrical shape or a prismatic shape, the uniformity (uniformity) of the light emission intensity distribution of the light emitting device 1 can be corrected by a plurality of steps 10e as described later. can be done.

The lens region 10b is a region having a light extraction surface 10d for extracting light propagating inside the light guide region 10a to the outside on the opposite side of the light guide region 10a.

The shape of the lens region 10b is typically rectangular parallelepiped as shown in FIGS.

In order to efficiently guide the light into the light guide region 10a, the width of the lens region 10b (the length in the vertical direction in FIG. 1 and the length in the horizontal direction in FIG. 4) should be smaller than the width of the light guide region 10a. is preferred.

The light guide region 10a preferably has a plurality of steps 10e on the opposite side of the lens region 10b, as shown in FIGS. A plurality of steps 10e are provided continuously along the length direction of the light guide region 10a. For example, as shown in FIG. 3, the step 10e is formed as a continuous recessed step from the outside toward the inside on the bottom surface of the light guide region 10a located on the opposite side of the light extraction surface 10d. The concave shape can be, for example, a mountain-shaped concave shape, a cylindrical concave shape, a conical concave shape, a pyramid concave shape, and the like.

The step 10e can facilitate reflection of the light 14a propagating in the light guide region 10a toward the light extraction surface 10d of the lens region 10b. Further, by adjusting the shape of the plurality of steps 10e so that the more light is reflected on the steps 10e as the distance from the light intake surface 10c increases, the uniformity of the light emission intensity distribution of the light emitting device 1 is improved. can be made

The light guide 10 is made of a transparent material, such as polycarbonate (PC) or polymethyl methacrylate (PMMA), through which the light emitted from the light emitting element 14 can pass.

(First cover 11)
The first cover 11 covers the surface of the light guide region 10a with an air layer 18 interposed therebetween. Therefore, the surface of the light guide region 10a is covered with the air layer 18. As shown in FIG. Since the first cover 11 covers the entire surface of the light guide region 10a, as shown in FIG. 4, the end portion covers a part of the side surface 10f of the lens region 10b on the light guide region 10a side. is preferred. Here, the side surfaces 10f are surfaces along the length direction of the lens region 10b on both sides of the light extraction surface 10d.

The refractive index of air is 1.0, which is less than the refractive index of the light guide 10 (for example, approximately 1.6 when made of PC and approximately 1.5 when made of PMMA). By totally reflecting the light at the interface of the layer 18, attenuation of the light propagating in the light guide region 10a can be suppressed. In addition, since the refractive index of air is smaller than the refractive index of the first cover 11 (for example, about 1.5 when made of PP), the difference from the refractive index of the light guide 10 is large. The critical angle is smaller than when 11 is in close contact with the light guide 10, making it easier to satisfy the condition of total reflection. Therefore, it is possible to suppress a decrease in emission intensity in a region distant from the light intake surface 10c.

The first cover 11 can be formed by insert molding or two-color molding using a material having poor adhesion to the light guide 10 and using the light guide 10 as a base member. According to this method, since the light guide 10 and the first cover 11 are not in close contact with each other, a gap, that is, an air layer 18 is naturally formed between the light guide 10 and the first cover 11 .

A material having poor adhesion to the light guide 10 is, for example, a material different from the material forming the light guide 10 . For example, when the light guide 10 is made of PC or PMMA, it is preferable to use polypropylene (PP) as the material of the first cover 11 from the viewpoint of poor adhesion and cost.

In order to efficiently reflect the light not reflected at the interface between the light guide 10 and the air layer 18, the first cover 11 is preferably a white member containing a white dye such as titanium oxide. If it is desired to avoid seeing white when the light-emitting device 1 is not lit, the first cover 11 may be a black member containing a black dye such as carbon black.

(Second cover 12)
The second cover 12 is closely connected to the first cover 11 to cover the remaining surface of the light guide 10 and transmit the light 14a. The second cover 12 is welded to the first cover 11 at each end.

As shown in FIG. 4, the remaining surface 10g where the air layer 18 between the first cover 11 and the light guide 10 is not formed is covered with the second cover 12. As shown in FIG. As a result, the entire surface of the light guide 10 is covered with the first cover 11 and the second cover 12 .

As for the second cover 12, the end 12a of the second cover 12 is welded to the end 11a of the first cover 11, as shown in FIG. As a result, the second cover 12 is closely connected to the first cover 11 and can seal the air layer 18 . Also, water can be prevented from entering the air layer 18 . Since water has a higher refractive index than air, when water enters the air layer 18, it becomes difficult to satisfy the conditions for total reflection.

Further, since the second cover 12 covers the lens region 10b and the light extraction surface 10d of the light guide 10, the light guide 10 can be protected from scratches and the like.

The melting temperature of the second cover 12 is set higher than the melting temperature of the first cover 11 .

The second cover 12 can be formed by insert molding using the light guide 10 covered with the first cover 11 as a base member. According to this method, since the first cover 11 and the second cover 12 are brought into close contact with each other, the air layer 18 between the light guide 10 and the first cover 11 is sealed, and waterproofness can be ensured. .

For the second cover 12, for example, a transparent material such as polycarbonate (PC) or polymethylmethacrylate (PMMA) that can transmit light emitted from the light emitting element 14 can be used.

(Manufacturing method of light-emitting device 1)
In the method of manufacturing the light emitting device 1, first, in the light guide 10, a light guide region 10a for propagating the light incident from the light emitting element 14 inside; The first cover 11 is welded to the lens region 10b of the light guide 10 having the lens region 10b for extracting the light propagating from the light guide 10 to the outside to cover the light guide region 10a via an air layer. The first cover 11 covers the surface up to the region 10b. For the first cover 11, by using a material having poor adhesion to the light guide 10, for example, a material different from the material forming the light guide 10, the light guide 10 and the first cover 11 are A gap, that is, an air layer 18 is naturally formed between the light guide 10 and the first cover 11 without being in close contact with each other.

The light guide 10 covered with the first cover 11 formed by the above steps is set in a mold (not shown) as an insert part, and the second cover 12 is insert-molded. The second cover 12 covers the lens region 10b and the light extraction surface 10d of the light guide 10, and is welded to the first cover 11 at each end.

In addition to the above steps, the light emitting device 1 is completed by attaching the light emitting element 14, the heat sink 16, and the like.

(Light emitting element 14)
An LED is typically used as the light emitting element 14 . An LED is a small light-emitting element, consumes little power, generates little heat, and has a long life. Note that the light emitting elements 14 may be installed at both ends of the light guide 10 in the length direction. In that case, light intake surfaces 10c are provided at both ends of the light guide 10 in the length direction.

A light emitting element 14 is mounted on the substrate 13 . The substrate 13 is a wiring substrate having wirings connected to the electrodes of the light emitting elements 14 .

The substrate 13 has holes 13a for positioning. A protrusion 10i that is a part of the light guide 10 is inserted into the hole 13a to determine the position of the substrate 13 with respect to the light guide 10, that is, the position of the light emitting element 14 with respect to the light guide 10. FIG. The positioning of the light emitting element 14 with respect to the light guide 10 is important for efficiently guiding the light emitted from the light emitting element 14 into the light guide 10 .

The protrusion 10i for positioning the substrate 13 may be provided as a part of (the housing 15 which is a part of) the first cover 11. Since the position of is important, the protrusion 10i is preferably part of the light guide 10. FIG.

A housing 15 that houses the light emitting element 14 is a part of the first cover 11 and prevents light leakage to the outside.

The heat sink 16 is a heat radiation member for releasing heat generated from the light emitting element 14 and is fixed to the housing 15 . The substrate 13 is fixed to the heat sink 16 directly or via another layer.

Moreover, it is preferable that the space in the housing 15 be sealed by an annular sealing member 17 installed between the housing 15 and the heat sink 16 . The sealing member 17 is, for example, an O-ring or packing, and exhibits a sealing function by sandwiching the sealing member 17 between the housing 15 and the heat sink 16 and compressing it appropriately.

(Modification 1)
FIG. 5(a) is a view corresponding to FIG. 4, showing a modification of the embodiment of the present invention. The first cover 11 covers the surfaces of the light guide region 10a and the lens region 10b with an air layer 18 interposed therebetween. The second cover 12 is closely connected to the first cover 11 to cover the remaining surface of the light guide 10 and transmit the light 14a. As for the second cover 12, as shown in FIG. 5A, the end 12b of the second cover 12 is welded to the end 11b of the first cover 11. As shown in FIG. As a result, the second cover 12 is closely connected to the first cover 11 and can seal the air layer 18 .

Further, the second cover 12 covers the lens area 10b of the light guide 10 and the light extraction surface 10d. As a result, the entire surface of the light guide 10 is covered with the first cover 11 and the second cover 12, so that the first cover 11 and the second cover 12 can ensure the airtightness. , the light guide 10 can be protected from scratches and the like.

(Modification 2)
FIG. 5(b) is a view corresponding to FIG. 4, showing another modification of the embodiment of the present invention. Modification 2 shown in FIG. 5B has the same configuration as Modification 1 shown in FIG. 5A, but the shape of the second cover 12 is different. As shown in FIG. 5B, the width of the light emitting portion 12c of the second cover 12 is set to a predetermined width W. As shown in FIG.

The predetermined width W is, for example, substantially the same width as the width _W10 of the lens region 10b of the light guide 10, that is, the light extraction surface 10d. can be taken out. Further, when installed on the mesh ₂₂ of the front grille 20 of the vehicle 100 to be described later, as shown in FIG. . In addition, it is possible to adapt to various types of vehicles by simply changing the shape of the second cover 12 .

(Usage example of light emitting device 1)
FIG. 6A is an example of a member (design member) to which the light emitting device 1 is attached when the light emitting device 1 is applied to a vehicle, and is a schematic diagram of the front grille 20 of the vehicle. FIG. 6B is a cross-sectional view of the light emitting device 1 installed on the front grille 20. As shown in FIG.

The front grille 20 has a frame 21 and a mesh 22 installed within the frame. The openings in the mesh 22 function as air intakes for drawing air into the vehicle's engine and radiator.

In the example shown in FIG. 6A, the mesh 22 is composed of a linear portion 22a extending in the vertical direction and a linear portion 22b extending in the horizontal direction, and the light emitting device 1 is installed on the linear portion 22a. In FIG. 6A, an example of the installation position of the light emitting device 1 is schematically shown by dotted lines.

The light emitting device 1 is installed on the back side of the linear portion 22a of the mesh 22, and the second cover 12 of the light emitting device 1 is exposed through the linear opening provided in the linear portion 22a. Thereby, the linear portion 22a can be caused to linearly emit light.

When the light-emitting device 1 is installed on the front grille 20, the width of the light-emitting device 1 is small, so it does not protrude from the linear portion 22a and deteriorate the aesthetic appearance. Moreover, since the opening area of the mesh 22 is not narrowed, the intake function of the front grille is not deteriorated.

For example, as shown in FIG. 6(b), the light emitting device 1 is fixed to the intersection of the linear portions 22a and 22b of the mesh 22 by screwing. Specifically, the screw fixing portion 24 provided on the back side of the crossing portion of the linear portion 22a and the linear portion 22b of the mesh 22, and the projection portion 11c for screwing which is a part of the first cover 11. is fixed by a screw 25.

Since the light-emitting device 1 is excellent in waterproofness, it can be installed in a place where water adheres, such as an exterior part of a vehicle. In addition to the front grille, examples of vehicle installation locations include design members such as plated moldings and garnishes, and gaps between garnishes and the body.

(Effect of Embodiment)
According to the light emitting device 1 of the above embodiment, the air layer 18 that covers the rod-shaped light guide 10 can be easily and thinly formed by the first cover 11, and the second cover 12 and the first cover The close contact with 11 can ensure waterproofness. Therefore, it is possible to provide a light emitting device as a linear light source using a rod-shaped light guide, which is waterproof and has a small width.

The light emitting device 1 composed of the light guide 10, the first cover 11 and the second cover 12 has a smaller width than the conventional light emitting device in which the light guide is housed inside the lens and the case. It can be installed even on a member with a small width without impairing its function and aesthetic appearance.

Although the embodiments and modifications thereof of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the invention. Moreover, the above embodiments do not limit the invention according to the scope of claims. Also, it should be noted that not all combinations of features described in the embodiments are essential to the means for solving the problems of the invention.

Reference Signs List 1 Light emitting device 10 Light guide 10a Light guide area 10b Lens area 10c Light intake surface 10d Light extraction surface 10e Step 10f Side surface 10g Remaining surface 10i Projection 10j Region 11 First cover 11a End 11b End 11c Protrusion 12 Second cover 12a End 12b End 12c Light emitting portion 13 Substrate 13a Hole 14 Light-emitting element 14a Light 15 Housing 16 Heat sink 17 Seal member 18 Air layer 20 Front grille 21 Frame 22 Mesh 22a Linear portion 22b Linear portion 24...Screw fixing portion 25...Screw W, _W10 ...Width _W22 ...Mesh width

Claims (5)

a light emitting element;
A light guide body having a light guide region for propagating light incident from the light emitting element inside, and a lens region continuously formed in the light guide region and extracting the light propagating inside the light guide region to the outside. ,
a first cover that covers the surface along a part of the surface of the light guide via an air layer;
a second light-transmissive cover intimately connected to the first cover and closely covering the remaining surface of the light guide;
A light emitting device. The light emitting device according to claim 1, wherein said second cover is welded to said first cover. 3. The light-emitting device according to claim 1, wherein said first cover is made of a material different from a material forming said light guide. The light emitting device according to any one of claims 1 to 3, wherein a melting temperature of said second cover is set higher than a melting temperature of said first cover. 5. The light emitting device according to claim 1, wherein said light guide is rod-shaped, and said light emitting element is arranged to face said rod-shaped end of said light guide.

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