JP2011151218A - Light emitting device - Google Patents

Abstract

A lens can be arranged close to a light source, and a light distribution pattern formed by the lens can be brightened as a whole.
A light emitting device includes a substrate 2, a light emitting element 32 provided on the substrate 2, a protrusion provided on the substrate 2 and covering the light emitting element 32, and diffuses and emits light from the light emitting element 32. A lens 5 facing the substrate 2 with the light emitting element 32 and the covering material 34 placed between the covering material 34 and the substrate 2, and surrounding the light emitting element 32 and the covering material 34 between the lens 5 and the substrate 2, And a reflecting surface 46 inclined in a direction away from the optical axis of the lens 5 in a direction approaching the lens 5 from the substrate 2.
[Selection] Figure 3

Description

  The present invention relates to a light emitting device.

  In a conventional light emitting device, a reflector is disposed between a light emitting surface of a light source that emits surface light and a lens, and surrounds the light emitting surface of the light source (for example, Patent Document 1). Since a part of the light emitted from the light source is directly incident on the lens and a part of the light is reflected by the reflector and then incident on the lens, the utilization efficiency of the light from the light source is improved.

JP 2006-216506 A

However, in the above structure, since the light irradiation angle by the light source that emits light is narrow, the light emitted from the light emitting surface hardly propagates in the direction parallel to the light emitting surface. If it does so, the light emitted from the light source will reflect in the part near a lens among reflectors, but it will not reflect in the part near a light source. Therefore, if the distance between the light source and the lens is reduced, even if a reflector is installed, the light emitted from the light source hardly enters the reflector, and the presence of the reflector is lost.
On the other hand, when there is no reflector or when the distance between the light source and the lens is small, only the direct light emitted from the light emitting surface of the light source is projected by the lens and the reflected light of the reflector is not projected. In particular, the intensity is increased, which is not a preferable light distribution pattern.
Therefore, it has been impossible to reduce the distance between the light source and the lens while obtaining a preferable light distribution pattern using the reflector, and it has not been possible to reduce the thickness of the light emitting device itself.

  Therefore, an object of the present invention is to enable the lens to be disposed close to the light source and to make the light distribution pattern formed by the lens bright overall.

In order to solve the above problems, a light-emitting device according to the present invention includes:
A substrate,
A light emitting device provided on the substrate;
A covering material provided so as to be raised on the substrate and covering the light emitting element, and diffusing and emitting the light of the light emitting element;
A lens facing the substrate by placing the light emitting element and the covering material between the substrate,
A reflection surface that surrounds the light emitting element and the covering material between the lens and the substrate, and is inclined in a direction away from the optical axis of the lens toward the lens from the substrate. .

  Preferably, a surface opposite to the surface facing the light emitting element of both surfaces of the lens is disposed alternately adjacent to and between the annular lens surfaces arranged concentrically around the optical axis. A fresnel lens surface having an annular rise surface.

  Preferably, the pitch of the Fresnel lens surface is 50 to 80 μm.

According to the present invention, the light emitting element is covered with the raised covering material, and the light emitted from the light emitting element is diffused by the covering material, so that the light emitted from the light emitting element is entirely emitted from the surface of the covering material. . Therefore, the emitted light on the surface of the covering material is directed not only to the front lens but also to the side. Since the light emitting element and the covering material are surrounded by the reflecting surface, the outgoing light directed from the surface of the covering material to the side is reflected by the reflecting surface, and the reflected light enters the lens. Therefore, not only the emitted light directed from the surface of the covering material toward the front lens, but also the reflected light reflected by the reflecting surface from the surface of the covering material to the side is projected by the lens. Therefore, the light distribution pattern formed by the lens can be brightened as a whole.
Further, even if the lens is installed close to the light source, the emitted light directed from the surface of the covering material to the side is reflected by the reflecting surface, so that the reflected light can be reliably and effectively used. . Therefore, the distance between the lens and the light source can be reduced, and the light emitting device can be reduced in thickness.

It is a disassembled perspective view of the light-emitting device in embodiment of this invention. It is a top view of the light-emitting device in the embodiment. It is arrow sectional drawing of the surface along the III-III line | wire shown by FIG. It is the top view, side view, and bottom view of the light source used for this embodiment. It is sectional drawing and the enlarged view of the lens used for this embodiment. It is a figure which shows the light emission intensity | strength of the upper surface light distribution at the time of light-emitting only the upper surface of a light source, and the light emission of the upper surface and side surface of a light source.

  EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated using drawing. However, although various technically preferable limitations for implementing the present invention are given to the embodiments described below, the scope of the invention is not limited to the following embodiments and illustrated examples.

  1 is an exploded perspective view of the light emitting device 1, FIG. 2 is a top view of the light emitting device, and FIG. 3 is a cross-sectional view taken along the line III-III shown in FIG. The light emitting device 1 includes a substrate 2, a light source 3, a reflector 4, a lens 5, and the like.

  The substrate 2 is formed in a rectangular shape, and the lower surface 22 of the substrate 2 constitutes the lower surface of the light emitting device 1. Cutouts 23 are formed at both ends of the substrate 2 in the longitudinal direction. Two light sources 3 arranged in the longitudinal direction are mounted at the center of the upper surface 21 of the substrate 2.

4A is a top view of the light source 3, FIG. 4B is a side view of the light source 3, and FIG. 4C is a bottom view of the light source 3.
The light source 3 includes a light source substrate 31, a light emitting element 32, a Zener diode 33, a covering material 34, and the like. A cathode electrode 35 and an anode electrode 36 are formed on the lower surface of the rectangular light source substrate 31. The lower surface of the light source substrate 31 is bonded to the upper surface 21 of the substrate 2, and the cathode electrode 35 and the anode electrode 36 are bonded to the terminals on the substrate 2. The light emitting element 32 and the Zener diode 33 are formed in a convex shape on the upper surface of the light source substrate 31. The light emitting element 32 is a light emitting diode, an inorganic electroluminescent element, an organic electroluminescent element, or other semiconductor light emitting elements. The Zener diode 33 prevents the light emitting element 32 from being electrostatically damaged.
The covering material 34 is provided on the upper surface of the light source substrate 31 so as to be raised, and the light emitting element 32 and the Zener diode 33 are covered with the covering material 34. The covering material 34 is a transparent mold resin containing a large number of fine particles (diffusing material) or pores (bubbles). The covering material 34 is formed in a rectangular parallelepiped shape. Since the fine particles or pores are dispersed in the coating material 34, the light emitted from the light emitting element 32 buried in the coating material 34 diffuses by the fine particles or pores. Therefore, the light emitted from the light emitting element 32 is emitted not only from the upper surface 34 a of the covering material 34 but also from the side surface 34 b of the covering material 34. The outgoing light emitted from the surface of the covering material 34 has the highest intensity directly above the center of the light emitting element 32 in the upper surface 34 a of the covering material 34. Note that the covering material 34 does not need to include a diffusing material. For example, light is diffused, for example, crumpled fine irregularities are formed on the surface of the covering material 34, or the surface of the covering material 34 is roughly polished. Then, it may be emitted. The light emitting element 32, the Zener diode 33, and the covering material 34 may not be provided on the light source substrate 31, and may be provided directly on the upper surface 21 of the substrate 2.

As shown in FIG. 1, the reflector 4 is a rectangular frame-like plate-like member, and is disposed so as to cover the upper surface 21 of the substrate 2. Convex portions 43 protrude from both longitudinal ends of the lower surface 42 of the reflector 4. The convex portion 43 is fitted to the notch portion 23 so that the reflector 4 is fixed to the substrate 2.
In the center of the reflector 4, a substantially elliptical opening 45 that penetrates from the upper surface 41 to the lower surface 42 of the reflector 4 is provided. A reflective film such as aluminum vapor deposition or silver coating is formed on the entire surface of the reflector 4, and a reflective surface 46 is formed on the inner wall of the opening 45. Two light sources 3 are arranged inside the opening 45, and the reflection surface 46 surrounds the light source 3 on the substrate 2. Since the thickness of the light source 3 is smaller than the thickness of the reflector 4, the light source 3 is contained in the opening 45.
The opening area of the opening 45 gradually increases from the lower surface 42 of the reflector 4 toward the upper surface 41. Therefore, the reflection surface 46 is inclined upward from the light source 3 along the upper surface 21 of the substrate 2 toward the outside.
In addition, protrusions 44 protrude from both ends of the upper surface 41 of the reflector 4 in the longitudinal direction.

With the lens 5 facing the upper surface 21 of the substrate 2, the lens 5 is mounted on the upper surface 41 of the reflector 4, and the opening 45 of the reflector 4 is blocked by the lens 5. A light source 3 is disposed between the lens 5 and the substrate 2.
Cutout portions 54 corresponding to the protrusions 44 of the reflector 4 are formed at both ends in the longitudinal direction of the lens 5. A projection 44 is fitted into the notch 54 and the lens 5 is fixed to the reflector 4.
The lens 5 is formed in a rectangular plate shape, and its thickness t is 1.0 mm. The lower surface 52 of the lens 5 is a flat surface. A substantially rectangular raised portion 55 is projected at the center of the upper surface 51 of the lens 5. Two Fresnel lens surfaces 56 are arranged on the upper surface of the raised portion 55 in the longitudinal direction. That is, the two Fresnel lens surfaces 56 are formed on the opposite surface (upper surface 51) side of the surface (lower surface 52) of the both surfaces of the lens 5 facing the light source 3. As a result, the distance between the light source 3 and the lens 5 can be shortened by the cut height of the Fresnel lens, and the light utilization efficiency of the light source 3 is improved. Furthermore, since the Fresnel lens surface 56 is formed on the upper surface 51 side, light can be taken in by the entire lower surface 52 of the lens 5, and the light utilization efficiency is further improved.
Each light source 3 is arranged on the optical axis Ax of each Fresnel lens surface 56. The lens thickness t is not limited to 1.0 mm, but may be 0.5 mm or more. This is because if the thickness is less than 0.5 mm, it is difficult to process the lens 5.

FIG. 5A is an enlarged view of a part of the cross section of the lens 5 shown in FIG. 3, and FIG. 5B is an enlarged view of a region C shown in FIG.
The Fresnel lens surface 56 includes a plurality of lens surfaces 561 and a plurality of rise surfaces 562. These lens surfaces 561 are formed in an annular band shape facing the outside of the optical axis Ax. These lens surfaces 561 are arranged concentrically around the optical axis Ax. The rise surface 562 is formed in an annular band shape facing the optical axis Ax side. The rise surface 562 is disposed between the lens surfaces 561 adjacent to the lens surface 561, and the rise surfaces 562 and the lens surfaces 561 are alternately arranged toward the outside of the optical axis Ax.

In a cross section passing through the optical axis Ax of the lens 5, the lens surface 561 is inclined upward in a direction approaching the optical axis Ax with respect to a plane orthogonal to the optical axis Ax. The inclination angle of the lens surface 561 with respect to the surface orthogonal to the optical axis Ax becomes larger as the lens surface 561 located on the outer side.
Of the rise surface 562, the one close to the optical axis Ax (the rise surface 562 in the region A in FIG. 5A) is parallel to the optical axis Ax. The other rise surface 562 (the rise surface 562 in the region B in FIG. 5A) is inclined upward in the direction away from the optical axis Ax with respect to the surface orthogonal to the optical axis Ax. . Therefore, a triangular cross section is formed by the lens surface 561 and the rise surface 562 adjacent to the inside thereof.

The distance P between the lower ends of two adjacent lens surfaces 561 (hereinafter referred to as pitch P) is constant in any lens surface 561, for example, pitch P = 50 to 80 μm. When the pitch P is 50 to 80 μm, impurities such as dust hardly adhere to the Fresnel lens surface 56.
Each lens surface 561 and the rise surface 562 are aligned at the lower end, and a surface passing through the lower ends of the lens surface 561 and the rise surface 562 is defined as a reference surface 563. The reference surface 563 is parallel to the lower surface 52 of the lens 5.
The distance h (hereinafter referred to as the cut height h) between the apex of the triangle formed by the lens surface 561 and the rise surface 562 adjacent to the inside of the lens surface 561 and the reference surface 563 is larger in the region A as it is located on the outer side. It is large, and any cut height h is less than 50 μm. In the region B, the cut height h is 50 μm or more.

  In the cross section passing through the optical axis Ax, the angle formed between the vertical line V drawn from the apex of the triangle formed by the lens surface 561 and the rise surface 562 adjacent to the lens surface 561 to the reference surface 563 and the rise surface 562 is a, An angle formed by the perpendicular V and the lens surface 561 is b. In the region A of the Fresnel lens surface 56, the angle a is set to zero degrees and the angle b is set to 50 degrees or more. In the region B, the angle a is set to be larger as it is located on the outer side, the angle b is set to be smaller as it is located on the outer side, and the sum of the angle a and the angle is set to 50 °. Yes. The values of the angles a and b are not limited to this.

The function of the light-emitting device 1 configured as described above will be described with reference to FIG.
When the light emitting element 32 emits light, the light is diffused by the covering material 34 and emitted from the upper surface 34 a and the side surface 34 b of the covering material 34. Since the upper surface 34 a faces the lens 5, the light emitted from the upper surface 34 a is incident on the lower surface 52 of the lens 5 in the region A and the region B of the lens 5. The light incident on the lower surface 52 is refracted toward the optical axis Ax and is emitted from the lens surface 561.
Since the side surface 34 b is orthogonal to the main surface of the lens 5, the light emitted from the side surface 34 b is not directly incident on the lens 5 but is incident on the reflecting surface 46. Since the reflecting surface 46 is inclined in a direction away from the optical axis Ax of the lens 2 toward the direction approaching the lens 5 from the substrate 2, the light incident on the reflecting surface 46 is reflected toward the lens 5 by the reflecting surface 46. The The reflected light is incident on the outer surface of the region B on the lower surface 52 of the lens 5, and is refracted and emitted from the lens surface 561. A lens surface 561 is formed so that the emitted light has a beam angle of 20 °.

FIG. 6 shows a light distribution when only the upper surface 34a of the light source 3 emits light and when the upper surface 34a and the side surface 34b emit light in the vertical direction and the left-right direction, respectively, with the light emission direction of the light emitting device 1 as the front. It is a figure which shows the result of having measured intensity | strength.
In the measurement result in the vertical direction in FIG. 6, the area is larger when the upper surface 34a and the side surface 34b are used than when only the upper surface 34a is used. This indicates that in the vertical orientation, not only the light from the upper surface 34a but also the light from the side surface 34b is used to increase the emission intensity.
Also in the measurement result in the left-right direction, the area is larger when the upper surface 34a and the side surface 34b are used than when only the upper surface 34a is used. Therefore, even in the light distribution in the left-right direction, not only the light from the upper surface 34a but also the light from the side surface 34b increases the light emission intensity.

As described above, according to the embodiment of the present invention, since the light emitting element 32 is covered with the light diffusion covering material 34, the light emitted from the light emitting element 32 is the surface of the covering material 32 (upper surface 34a, side surface). 34b) as a whole. Therefore, light emitted from the surface of the covering material 32 is directed not only to the lens 5 but also to the side. Since the reflecting surface 46 is disposed on the side of the covering material 32, the outgoing light directed from the surface of the covering material 32 to the side is reflected toward the lens 5 by the reflecting surface 46. Accordingly, not only the light directed directly from the surface of the covering material 32 toward the lens 5 but also the reflected light reflected by the reflecting surface 46 is projected by the lens 5. Therefore, the light distribution pattern formed by the lens 5 can be brightened as a whole.
Even if the lens 5 is installed close to the light source, the emitted light directed from the surface of the covering material 32 toward the side is reflected by the reflecting surface 46, so that the reflected light is reliably and effectively used. be able to. Therefore, the distance between the lens 5 and the light source 3 can be reduced, and the light emitting device 1 can be thinned.
Furthermore, since the Fresnel lens surface 56 is formed on the opposite surface (upper surface 51) side of the surface (lower surface 52) facing the light source 3 of the lens 5, the light source 3 and the lens corresponding to the cut height of the Fresnel lens. The distance to 5 can be shortened. Thereby, the light use efficiency of the light source 3 can be improved and the light emitting device 1 can be further thinned. Similarly, since the Fresnel lens surface 56 is formed on the upper surface 51 side of the lens 5, light can be captured by the entire lower surface 52 of the lens 5, and the light utilization efficiency is further improved.

DESCRIPTION OF SYMBOLS 1 Light-emitting device 2 Board | substrate 3 Light source 4 Reflector 5 Lens 32 Light emitting element 34 Cover material 34a Upper surface 34b Side surface 46 Reflecting surface 56 Fresnel lens surface 561 Lens surface 562 Rise surface

Claims (3)

A substrate,
A light emitting device provided on the substrate;
A covering material provided so as to be raised on the substrate and covering the light emitting element, and diffusing and emitting the light of the light emitting element;
A lens facing the substrate by placing the light emitting element and the covering material between the substrate,
A reflective surface that surrounds the light emitting element and the covering material between the lens and the substrate, and is inclined in a direction away from the optical axis of the lens toward a direction approaching the lens from the substrate. A light emitting device.   Of the two surfaces of the lens, the opposite surface of the surface facing the light emitting element is an annular lens surface arranged concentrically around the optical axis, and an annular shape arranged alternately adjacent to the lens surface. The light-emitting device according to claim 1, wherein the light-emitting device has a rising surface.   The light emitting device according to claim 2, wherein the pitch of the Fresnel lens surface is 50 to 80 μm.

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