JP7243330B2 - Light-emitting element, vehicle lamp, and method for manufacturing light-emitting element - Google Patents

Description

The present invention relates to a light-emitting element, a vehicle lamp, and a method for manufacturing a light-emitting element.

2. Description of the Related Art Conventionally, a vehicle lamp such as a headlamp emits light from a light-emitting element to the outside through an optical member such as a reflector or a lens to form a light distribution image on a road surface or ahead. As a light-emitting element for such a vehicle lamp, there has been proposed a light-emitting element having a plurality of optical semiconductor chips and a plurality of fluorescent plate members provided on each of the plurality of optical semiconductor chips. This vehicle lamp superimposes the light from each optical semiconductor chip to form a predetermined light distribution.

Here, in the light emitting element, a gap is formed between the fluorescent plate members so that the fluorescent plate members do not overlap each other due to variations in positional accuracy. Since these gaps become dark areas in the light distribution, it is necessary to use a large number of light-emitting images to eliminate the dark areas, making it difficult to design and form a satisfactory light distribution.

Therefore, a light-emitting element provided with a fluorescent plate material that collectively covers a plurality of optical semiconductor chips has been proposed (see Patent Documents 1 and 2, for example). According to this light-emitting element, the above-described dark areas can be eliminated by collectively covering the plurality of optical semiconductor chips with the fluorescent plate material.

JP 2011-124088 A International Publication No. 2014/171277

However, as shown in FIGS. 4A and 4B, the plurality of optical semiconductor chips 113 in the light-emitting elements described in Patent Documents 1 and 2 have their surfaces close to the phosphor due to variations in thickness thereof. The position of the (upper surface) in the optical axis direction (height direction) will vary. Further, since the fluorescent plate material 115 is supported by glass or ceramic, the surface on the side of the plurality of optical semiconductor chips 113 is flat. Therefore, the thickness of the adhesive layer 114 that bonds the plurality of optical semiconductor chips 113 and the fluorescent plate material 115 is different for each optical semiconductor chip 113 . Since the adhesive layer 114 has extremely poor thermal conductivity, the heat from the optical semiconductor chip 113 in the thick portion of the adhesive layer 114 is difficult to dissipate, resulting in color unevenness and luminance unevenness due to high temperature.

It should be noted that this problem is not limited to the case where the light emitting element has a fluorescent plate material, but is a common problem in cases where the light emitting element is provided with other light-transmitting plate materials such as a protective plate material containing a diffusing material.

SUMMARY OF THE INVENTION The present invention has been made in order to solve such conventional problems. It is another object of the present invention to provide a light-emitting element, a vehicle lamp, and a method for manufacturing a light-emitting element that can reduce the possibility of color unevenness and luminance unevenness.

A light-emitting element according to one aspect of the present disclosure includes a plurality of optical semiconductor chips that emit light, and an adhesive layer provided on the light emitting side of the plurality of optical semiconductor chips to collectively cover the plurality of optical semiconductor chips. a plate-shaped member made of a light-transmitting resin, the plate-shaped member having a specific surface, which is a surface on the side of the plurality of optical semiconductor chips, on which positions of the upper surfaces of the plurality of optical semiconductor chips in the optical axis direction are aligned The distance between the specific surface and the upper surface of each optical semiconductor chip is made uniform by the stepped portion, and the distance between the specific surface and the upper surface of each optical semiconductor chip is made uniform by the adhesive layer. Thus, the thickness between each optical semiconductor chip and the plate-shaped member is made uniform.

Further, a vehicle lamp according to one aspect of the present disclosure includes the light emitting element described above and an optical member for guiding light from the light emitting element to the outside.

Further, in the method for manufacturing a light-emitting element according to one aspect of the present disclosure, a first step of placing a semi-cured plate-shaped member made of a light-transmitting resin on a plurality of arranged optical semiconductor chips. Then, the plate-shaped member placed in the first step is pressed toward the plurality of optical semiconductor chips through the adhesive layer , and the plurality of optical semiconductor chips are attached to the specific surface, which is the surface on the side of the plurality of optical semiconductor chips. a second step of equalizing the distance between the specific surface and the upper surface of each optical semiconductor chip by forming a stepped portion according to the variation in the position of the upper surface in the optical axis direction; and a third step of curing the member, wherein the adhesive layer is formed by equalizing the distance between the specific surface and the upper surface of each optical semiconductor chip in the second step, thereby bonding each optical semiconductor chip and the plate-like member. The thickness between them is uniform .

INDUSTRIAL APPLICABILITY According to the present invention, a light-emitting element and a vehicle use that can eliminate dark portions of a projected image and reduce the possibility of color unevenness and luminance unevenness even if there is variation in the position of the top surface of an optical semiconductor chip in the optical axis direction. It is possible to provide a lamp and a method for manufacturing a light-emitting element.

1 is a side cross-sectional view showing a vehicle lamp according to this embodiment; FIG. FIG. 2 is a side cross-sectional view showing details of the light emitting element shown in FIG. 1; It is process drawing which shows the manufacturing method of the light emitting element which concerns on this embodiment, (a) shows the 1st process, (b) shows the 2nd process, (c) has shown the 3rd process. It is a side cross-sectional view showing a vehicle lamp according to a comparative example, (a) shows the overall view, (b) shows a partially enlarged view.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below along with preferred embodiments. It should be noted that the present invention is not limited to the embodiments described below, and can be modified as appropriate without departing from the gist of the present invention. In addition, in the embodiments shown below, there are places where illustrations and explanations of some configurations are omitted, but the details of the omitted technologies are as long as there is no contradiction with the contents explained below. Needless to say, well-known or well-known techniques are applied as appropriate.

FIG. 1 is a side cross-sectional view showing a vehicle lamp according to this embodiment. As shown in FIG. 1, a vehicle lamp 1 is, for example, a headlamp that is installed in front of a vehicle and emits light forward, and includes a light emitting element 10, a reflector (optical member) 20, and a heat sink. A member 30 and a lens portion (optical member) 40 are provided.

The light emitting element 10 includes a plurality of optical semiconductor chips (symbol 13 described later) that serve as light sources, and emits light from the plurality of optical semiconductor chips 13 toward the reflector 20 . The reflector 20 is a reflecting member that reflects light toward the lens portion 40, and has a concave reflecting surface 20a formed of, for example, a spheroidal surface. The concave reflecting surface 20a forms a first focal point F1 and a second focal point F2, and the plurality of optical semiconductor chips of the light emitting element 10 are arranged at the first focal point F1.

The heat sink member 30 is for dissipating heat from the light emitting element 10 and has a plurality of L-shaped fins 31 . The heat sink member 30 also serves as a base on which the light emitting elements 10 and the reflectors 20 are collectively arranged. Further, the heat sink member 30 forms a shade 32 on the front end side. The shade 32 forms a light distribution pattern by blocking or reflecting part of the light emitted from the light emitting element 10 and reflected by the reflector 20 .

The lens part 40 transmits the light reflected by the reflector 20 and emits the light as parallel light substantially parallel to the horizontal plane, for example.

In the vehicle lamp 1 as described above, the light from the light emitting element 10 is reflected by the concave reflecting surface 20a of the reflector 20, condensed near the second focal point F2 (for example, the front end position of the shade 32), and partially blocked. After being reflected, the light is led to the outside through the lens portion 40 .

FIG. 2 is a side sectional view showing details of the light emitting device 10 shown in FIG. As shown in FIG. 2, the light emitting device 10 includes a substrate 11, a chip bonding material 12, a plurality of optical semiconductor chips 13, an adhesive layer 14, and a plate member (optical wavelength changing plate) 15.

The substrate 11 has a circuit pattern formed thereon for causing the plurality of optical semiconductor chips 13 to emit light, and is mainly composed of an insulating material such as glass epoxy, resin, ceramics, or the like. A plurality of optical semiconductor chips 13 are mounted on the substrate 11 with chip bonding materials 12 interposed therebetween.

The plurality of optical semiconductor chips 13 are mounted with one or more LEDs (Light Emitting Diodes) and emit light in the height direction (optical axis direction) shown in FIG. The adhesive layer 14 joins the plurality of optical semiconductor chips 13 and the plate member 15 . Since the adhesive layer 14 may have extremely poor thermal conductivity, it is preferable to minimize the thickness of the adhesive layer 14 .

The plate member 15 is provided on the light emitting side of the plurality of optical semiconductor chips 13 with the adhesive layer 14 interposed therebetween. The plate-like member 15 has a light-transmitting transparent resin such as silicone resin that can be slightly deformed as a base material. It is composed of a fluorescent plate material to which a wavelength changing material) 16 is added. The plate member 15 is not limited to transparent resin, and may be made of colored resin as long as it is light transmissive.

Here, the plate-like member 15 has a step portion 15a formed on the surface thereof facing the plurality of optical semiconductor chips 13 for absorbing variations in the positions of the upper surfaces of the plurality of optical semiconductor chips 13 in the height direction. As shown in FIG. 2, the plurality of optical semiconductor chips 13 have some variation in the position of their top surfaces in the height direction due to variations in chip thickness and chip bonding material thickness. The upper surface of the plate member 15 has a concave portion 15b with respect to the optical semiconductor chip 13 slightly protruding to one side, and a convex portion 15c with respect to the optical semiconductor chip 13 slightly recessed to the other side.

As a result, even if the positions of the upper surfaces of the plurality of optical semiconductor chips 13 vary in the optical axis direction, the distance between the upper surface of each optical semiconductor chip 13 and the plate member 15 can be made uniform. This prevents the adhesive layer 14 from becoming thicker for a specific optical semiconductor chip 13, and reduces the possibility of color unevenness and brightness unevenness.

Further, the density of the phosphor particles 16 is higher in the portion of the plate member 15 where the concave portions 15b are formed than in the portion where the convex portions 15c are formed. That is, in the plate member 15, the density of the phosphor particles 16 is increased as the thickness of the plate member 15 decreases.

As a result, the number of phosphor particles 16 is ensured in the portion with a small plate thickness as well as in the portion with a large plate thickness, thereby reducing the possibility of occurrence of color unevenness.

Although not shown, a reflective member is provided around the plurality of optical semiconductor chips 13, the adhesive layer 14, and the plate-shaped member 15 on the substrate 11. This is to prevent light leakage.

Next, a method for manufacturing the light emitting device 10 according to this embodiment will be described. 3A and 3B are process diagrams showing the method for manufacturing the light emitting device 10 according to the present embodiment, in which (a) shows the first step, (b) shows the second step, and (c) shows the third step. showing.

First, as shown in FIG. 3A, a plurality of optical semiconductor chips 13 are mounted on a substrate 11 with chip bonding materials 12 interposed therebetween. Next, a plate member 15 having an adhesive layer 14 is prepared and placed so that the adhesive layer 14 faces the plurality of optical semiconductor chips 13 . At this time, the resin of the prepared plate member 15 is in a B-stage state (semi-cured state). Further, the plate member 15 contains phosphor particles 16 at a substantially uniform density. The adhesive layer 14 may be applied to the upper surface of the optical semiconductor chip 13 by a dispensing method or the like.

Next, as shown in FIG. 3B, the plate member 15 in the B-stage state is pressed against the plurality of optical semiconductor chips 13 . Here, since the upper surfaces of the plurality of optical semiconductor chips 13 have positional variations in the height direction, a stepped portion 15a is formed in the plate member 15 in the B-stage state by pressing. Further, since the plate-shaped member 15 contains the phosphor particles 16 at a substantially uniform density, the density of the phosphor particles 16 is becomes higher. That is, the density of the phosphor particles 16 increases as the plate thickness of the plate member 15 decreases. When pressing, a surface wider than the plate-like member 15 is used so that unevenness is not formed on the surface of the plate-like member 15 opposite to the side of the plurality of optical semiconductor chips 13 .

Next, after the plate-like member 15 adjusts to variations in the height of the upper surfaces of the plurality of optical semiconductor chips 13, the plate-like member 15 is cured as shown in FIG. 3(c). At this time, the plate-like member 15 is exposed to, for example, a high-temperature environment to be completely hardened.

As described above, according to the light emitting device 10 according to the present embodiment, since the plate-like member 15 made of a light-transmitting resin that collectively covers the plurality of optical semiconductor chips 13 is provided, It is possible to eliminate the dark part of the projected image based on the gap between the Further, since the plate-shaped member 15 is formed with a stepped portion 15a corresponding to variations in the positions of the upper surfaces of the plurality of optical semiconductor chips 13 in the optical axis direction, the positions of the plurality of optical semiconductor chips 13 can be adjusted in the optical axis direction. Even if there is variation, the distance between each optical semiconductor chip 13 and the plate-shaped member 15 can be made uniform, preventing the adhesive layer 14 from becoming thick for a specific optical semiconductor chip 13, This reduces the possibility of color unevenness and luminance unevenness.

In addition, since the plate-like member 15 contains phosphor particles 16 that change the wavelength of the irradiated light, when the stepped portion 15a is formed by pressing or the like, the plate-like member 15 has a small plate thickness. As for the large portion, the number of phosphor particles 16 is ensured to reduce the possibility of occurrence of color unevenness.

Further, according to the vehicle lamp 1 according to the present embodiment, the light emitting element 10, and the reflector 20 and the lens portion 40 for guiding the light from the light emitting element 10 to the outside are provided. It is possible to provide the vehicle lamp 1 that can reduce the possibility of color unevenness and luminance unevenness.

Furthermore, according to the method for manufacturing the light emitting element 10 according to the present embodiment, the semi-cured plate-like member 15 made of a light-transmitting resin is placed on the plurality of optical semiconductor chips 13 and placed. The plate-shaped member 15 thus formed is pressed toward the plurality of optical semiconductor chips 13 to form the stepped portion 15a corresponding to the positional variation of the upper surfaces of the plurality of optical semiconductor chips 13 in the optical axis direction. It is possible to manufacture the light-emitting element 10 in which the possibility of occurrence of color unevenness and brightness unevenness is reduced by forming the stepped portion 15a corresponding to different variations for each 10 by pressing.

As described above, the present invention has been described based on the embodiments, but the present invention is not limited to the above embodiments, and modifications may be made without departing from the scope of the present invention. You may combine well-known and well-known techniques.

For example, although the vehicle lamp 1 according to the present embodiment includes the reflector 20, the present invention is not limited to this, and a direct-type lamp without the reflector 20 may be used. Also, the vehicle lamp 1 may include two or more reflectors 20 and lens portions 40 .

Furthermore, although the plate member 15 is a fluorescent plate material in this embodiment, it is not limited to this, and may be other light-transmitting plate materials such as a protective plate material containing a diffusing material.

Reference Signs List 1: Vehicle lamp 10: Light emitting element 11: Substrate 12: Chip bonding material 13: Optical semiconductor chip 14: Adhesive layer 15: Plate member (optical wavelength changing plate)
15a: step portion 15b: concave portion 15c: convex portion 16: phosphor particles (wavelength changing material)
20: Reflector (optical member)
20a: concave reflecting surface 30: heat sink member 31: fins 32: shade 40: lens portion (optical member)
F1: First focus F2: Second focus

Claims (4)

a plurality of optical semiconductor chips that emit light;
a plate-shaped member provided on the light emitting side of the plurality of optical semiconductor chips via an adhesive layer and made of a light-transmitting resin that collectively covers the plurality of optical semiconductor chips,
The plate-like member has a stepped portion corresponding to variations in the position of the upper surfaces of the plurality of optical semiconductor chips in the optical axis direction on a specific surface that faces the plurality of optical semiconductor chips. The distance between the specific surface and the upper surface of each optical semiconductor chip is made uniform ,
In the adhesive layer, the distance between the specific surface and the top surface of each optical semiconductor chip is made uniform, so that the thickness between each optical semiconductor chip and the plate member is made uniform.
A light-emitting device characterized by: 2. The light emitting device according to claim 1, wherein the plate-like member is a light wavelength changing plate containing a wavelength changing material that changes the wavelength of irradiated light. A light-emitting device according to claim 1 or claim 2;
an optical member for guiding light from the light emitting element to the outside;
A vehicle lamp comprising: a first step of placing a semi-cured plate-shaped member made of a light-transmitting resin on a plurality of arranged optical semiconductor chips;
The plate-shaped member placed in the first step is pressed toward the plurality of optical semiconductor chips through an adhesive layer , and the plurality of optical semiconductors are attached to the specific surface on the side of the plurality of optical semiconductor chips. a second step of equalizing the distance between the specific surface and the top surface of each optical semiconductor chip by forming a stepped portion corresponding to variations in the position of the top surface of the chip in the optical axis direction;
and a third step of curing the plate-shaped member pressed in the second step ,
In the adhesive layer, the distance between the specific surface and the upper surface of each optical semiconductor chip is made uniform in the second step, so that the thickness between each optical semiconductor chip and the plate member is made uniform. there is
A method for manufacturing a light-emitting device, characterized by:

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