JP2002118290A - Light source device and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source device of high productivity and excellent light distribution characteristics. SOLUTION: A plurality of light-emitting diodes 30 manufactured by a transfer mold method are surface-mounted on the lower surface of a substrate 10 using a cream solder. Optical base bodies 20 provided in the radial direction of the light-emitting diodes are integrally provided with a plurality of reflective concave surfaces 21 corresponding to the light-emitting diodes 30 which correspond to the base bodies. The light from the light-emitting diode 30 is reflected on the corresponding reflective concave surface 21, and then converged into an arcuate, in top view, optical opening part 11 formed at the substrate 10. The light is projected outside through the optical opening part 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a light source device using a light emitting diode and a method of manufacturing the same.

[0002]

2. Description of the Related Art A light source device in which a large number of light emitting diodes (LEDs) are arranged on a substrate is used for illumination, display, signal use, and the like. As an LED for such a light source device, a lens-type LED having a φ5 mm size is widely used because sufficient light distribution characteristics can be obtained. This lens type L
The ED is designed so that light emitted from a semiconductor light emitting element is condensed by a lens unit and emitted to the outside with a certain degree of directivity. For this reason, by arranging a plurality of LEDs capable of external radiation on the substrate, it is possible to theoretically expect optical characteristics that are multiples of the number of mounted LEDs with respect to the characteristics of a single LED.

[0003] However, it is actually difficult to realize the optical characteristics according to the theory. The first reason
In addition, there is a problem that the axial accuracy of each lens-type LED is low. In particular, in a lens-type LED made by potting mold, the problem of axial accuracy is inevitable. Secondly, when mounting a plurality of lens-type LEDs on a substrate, there is a problem that it is not always easy to accurately align the directions and heights of the LEDs. In particular, in the case of discrete mounting, individual adjustment work is often required in order to align the axes of the emitted light of the LEDs in the same direction.

[0004] This situation will be described more specifically by taking as an example the case where a lens-type LED is applied to various light sources. For example, as shown in FIG.
In the light source device using the LED, the leads 74 of the lens-type LED 73 are inserted into holes 72 formed in advance on a single mounting substrate 71, and each lead 74 is soldered to the substrate 71.

In such a light source, it is required to increase the mounting density per unit area in order to secure sufficient luminance.
The number of LEDs 73 attached to one mounting board 71 may be as many as several hundred in the case of a light source device for a signal lamp. Further, in a light source device used for photographing with a CCD camera, for example, the mounting density of the LEDs 73 per unit area is further increased as compared with the light source device for a signal lamp. In this light source device, the LEDs 73 are mounted on the mounting board 71 in a state where they are in contact with each other.

Here, a lens type LE as shown in FIG.
D73 is generally manufactured by a potting mold. As shown in FIG. 11, the potting mold mounts a semiconductor light emitting element 75 at the tip and connects a pair of leads 74 electrically connected to the semiconductor optical element 75 via a bonding wire 76 to a resin molding case (pot) 77. The semiconductor light emitting element 75 is sealed in a lens 78 (see FIG. 10) made of a transparent resin by disposing a liquid resin therein and thermally curing the resin.
Means a method of manufacturing An outline of this potting mold is disclosed in, for example, Japanese Patent Application Laid-Open No. 7-183440. Lens type LE made by potting mold
In the case of D73, a pair of leads 74 extend from the resin lens 78 in parallel along the axial direction of the lens 78.

The following disadvantages are pointed out in this conventional LED light source. First, in the discrete mounting, when the mounting density is extremely high, such as a light source device used for photographing with the CCD camera, it is difficult to perform automatic dense mounting using an automatic machine (or a robot). For this reason, it is often necessary to rely on manual labor in order to implement very high-density discrete mounting. In general, the manual work requires a great deal of time for the mounting work. Further, it is difficult to make uniform the height and the mounting angle of the lens-type LED mounted on the substrate, and the height and the mounting angle of the LED are likely to be uneven. Therefore, L
In some cases, the aggregate of EDs cannot sufficiently exhibit the original brightness (instability of light distribution characteristics). Then, there is a problem in that adjustment of the light distribution characteristics requires much more labor.

As pointed out in Japanese Patent Application Laid-Open No. 7-183440, generally, in a potting mold, the lead 74 (and its frame) is easily inclined with respect to the pot 77 when casting resin. In each of the LEDs 73, a deviation easily occurs between the central axis of the lens 78 and the optical axis of the light emitted from the light emitting element 75. That is, the lens-type LED 73 as an attachment part
It is difficult to increase the axis accuracy of itself.

As described above, the lens type LED 73 is
Needless to say, manual mounting is required for discrete mounting on the LED 1, and even after mounting, individual mounting such as fine adjustment of the mounting angle of each LED 73 by hand in order to align the emission direction of light from each LED 73. Correction work is considered indispensable, and its low productivity is a problem.

As a method of manufacturing an LED while securing a high positional accuracy of a lens with respect to a light emitting element, it has been conventionally proposed to apply a transfer mold, for example. In this transfer mold,
In a state where the lead frame is sandwiched and fixed by a pair of upper and lower molds when sealing the light emitting element with a resin, a liquid resin is poured into a cavity of the mold to form a lens portion.

However, even in the LED manufactured by the transfer mold, it is necessary to form the lens portion to have a diameter of 5 mm or more in order to obtain a sufficient light distribution effect. Here, in the LED manufactured by the transfer mold, the sealing resin amount may be larger than that of the LED 73 manufactured by the potting mold described above and having the lens 78 of substantially the same size. For this reason, at the time of mounting the LED, the sealing resin is largely thermally deformed due to the heat history of the thermosetting treatment of the cream solder for fixing the LED lead on the substrate, which may cause inconvenience such as disconnection of the bonding wire. there were.

An object of the present invention is to provide a light source device capable of improving the light distribution characteristics as a whole and stabilizing the light distribution characteristics and increasing the productivity as compared with the conventional light source device. Another object of the present invention is to provide a method for manufacturing such a light source device.

[0013]

According to a first aspect of the present invention, there is provided a light source device comprising: a plurality of light emitting diodes having a light emitting element sealed in a light transmitting material; And one or more substrates,
A plurality of optical means are arranged in an integrated state corresponding to the light emitting diodes in the light emitting direction of the light emitting diodes.

First, "surface mounting" refers to a mounting method in which a light emitting diode is directly fixed to the surface of a substrate without forming holes or recesses for inserting leads extending from the light emitting diode in the substrate, and at least discrete mounting. Is a concept that does not include According to this light source device, since each light emitting diode is surface-mounted on the substrate, automatic mounting by an automatic machine is facilitated while increasing the mounting density per unit area, and the mounting height and mounting angle of the light emitting diode are reduced. It is easy to make them substantially uniform.

In addition, optical means are provided for each of the plurality of light emitting diodes on the substrate. Therefore, it is not necessary to control the light distribution in the light source only by the lens unit integrated with the light emitting element. Therefore, it is possible to reduce the size of the lens formed integrally with the light emitting diode, and it is not necessary to strictly control the positional accuracy between the light emitting element and the lens. In addition, even in a configuration in which automatic mounting was difficult due to the need for dense mounting in the past, the distance between adjacent light-emitting diodes can be increased without reducing the number of light-emitting diodes, thereby enabling automatic mounting. Implementation is also possible.

Moreover, the respective optical means are integrated with each other as an optical means group. In other words, the relative positional relationship between the individual optical means provided in one optical means group is determined for each optical means group, and the light emitted from each light emitting element is obtained only by aligning the optical means groups. Sufficient light distribution control can be realized. Accordingly, the light distribution of the light emitted from each light emitting diode can be controlled almost as desired by the corresponding optical means, and the optical characteristics of the entire light source device can be made closer to the theoretical characteristics.

As described above, the synergistic effect of the surface mounting of the light emitting diodes on the substrate and the integration of the respective optical means so as to correspond to the respective light emitting diodes makes it possible to efficiently provide a light source device having excellent light distribution characteristics. Can be mass-produced.

According to a second aspect of the present invention, in the light source device according to the first aspect, the optical means comprises a lens. According to this configuration, good light distribution characteristics can be realized in the light source device having the lens as the optical unit.

According to a third aspect of the present invention, in the light source device according to the first aspect, the optical means includes a reflection surface for controlling reflection of incident light. According to this configuration, good light distribution characteristics can be realized in the light source device having the reflection surface as the optical unit.

According to a fourth aspect of the present invention, in the light source device according to any one of the first to third aspects, the optical means has at least 4% of the area of the emission surface of the corresponding light emitting diode. It is characterized by having twice the plane area.

If the plane area of the optical means is less than four times, sufficient light distribution characteristics of the optical means cannot be obtained. According to a fifth aspect of the present invention, in the light source device according to the third aspect, the reflecting surface is a substantially annular reflecting concave surface surrounding a central axis of the corresponding light emitting diode, and the light from the light emitting diode is provided. It is characterized in that it has a concave surface shape such that the reflected light is condensed in an annular condensing area centered on the central axis.

According to this configuration, substantially all of the light amount emitted from each light emitting diode is received by the corresponding reflective concave surface, and the reflected light from the reflective concave surface is collected in the annular light collecting area, and The light is projected outside through the area. Since the annular light converging region exists at a predetermined distance from the central axis, the light emitting diode located on the central axis does not catch the light reflected by the reflective concave surface. By the time the light emitted from the light emitting diode is projected to the outside, there is almost no internal structure that blocks the light in the optical path. As described above, almost all of the light amount emitted from the light emitting diode is effectively projected to the outside, so that the external radiation efficiency of light is extremely high.

Further, since the light emitted from each light emitting diode is reflected by the reflecting concave surface and is projected to the outside through the annular light condensing area, when viewed from the front side of the light source device, one light emitting diode emits light. An annular or arcuate band of light occupying a certain area is created. Since the light source device includes a plurality of light emitting diodes and a plurality of reflecting concave surfaces corresponding to the plurality of light emitting diodes, the light source device as a whole produces a visual effect as if the entire front side is filled with uniform light. This enables the entire light emitting surface (the front of the light source device) to have a natural appearance without any gap without excessively increasing the mounting density of the light emitting diodes.

According to a sixth aspect of the present invention, in the light source device according to the fifth aspect, the reflecting concave surface has one focal point at a radially intermediate point of the light-collecting region and another light-emitting diode. It is characterized in that it has a shape in which an elliptical arc as a focal point is rotated around the central axis.

The reflecting concave surface according to this configuration is an elliptical surface obtained by rotating an elliptic arc having the light-emitting diode and a condensing area radially separated from the central axis by a predetermined distance around the central axis. It is provided as a concave surface according to. According to this configuration, the light reflected by the reflective concave surface of the light emitted from the light-emitting diode can be focused on the light-collecting region at the focal position of the elliptical arc, and the light amount and brightness of the light passing through the light-collecting region can be increased. It becomes possible.

According to a seventh aspect of the present invention, in the light source device according to the fifth or sixth aspect, the substrate has an arc centered on a central axis for each light-emitting diode mounted thereon. A plurality of optical apertures are provided along, and the annular light-collecting region is set substantially overlapping with each optical aperture, and portions of the substrate other than the optical aperture are light-shielding portions. It is characterized by being.

This light source device has a structural design assuming an optical path in which light emitted from each light emitting diode is reflected by the corresponding reflective concave surface and reaches the optical opening and the light condensing area. For this reason, even when external light that enters the optical opening from the outside during non-lighting enters the light source device in a manner reversely following the optical path, the external light reflected by the reflective concave surface is applied to the light emitting diode. There it is absorbed or irregularly reflected. Most of the light that repeatedly undergoes irregular reflection in the apparatus cannot be taken on the optical path that exits again through the optical opening as blocked by the light-shielding portion of the substrate. Therefore, the probability that external light that has entered the light source device follows the optical path again and goes out of the optical opening is extremely low. In other words, the rate at which the reflective concave surface reflects light derived from external light toward the optical opening when the light is not lit is extremely low, and the reflective concave surface does not cause so-called dark noise. For this reason,
According to the light source device of the present invention, it is possible to effectively avoid dark noise which is a problem in signal lamps and the like.

According to an eighth aspect of the present invention, there is provided a method of manufacturing a light source device, comprising the steps of: preparing a plurality of optical means groups in which a plurality of optical means are integrally provided; A step of surface mounting a plurality of light emitting diodes having light emitting elements sealed in, and mounting the plurality of optical means groups on the substrate by arranging them adjacent to each other in a light emission direction of the light emitting diodes Light emitting diode,
And a step of associating the optical means of each optical base group with the optical means.

This relates to a method of manufacturing the light source device according to the first to eighth aspects, and its technical significance is as described above. In this method, it is preferable that the light emitting diode to be surface-mounted on the substrate is manufactured by a transfer molding method.

[0030]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIGS. 1 and 2
Indicates a light source device according to the first embodiment that can be used, for example, as a light source for illumination. This light source device comprises a single substrate 15,
A plurality of light emitting diodes 30 mounted on the substrate 15
(Hereinafter referred to as LED 30) in the radiation direction of the substrate 1
And an optical base 20 as a plurality of optical element groups arranged at a predetermined interval from 5. Each of the optical bases 20 is formed by integrating a plurality of transmission lenses (outer lenses) 25 as optical means.

As shown in FIG. 1, a plurality of light emitting diodes 30 (hereinafter, referred to as LEDs 30) are provided on a substrate 15.
They are arranged at predetermined intervals in the horizontal direction. Assuming that the central axis of each LED 30 is Z, these LEDs 30
Are arranged such that each central axis Z occupies a lattice point position as shown in FIGS.

The LED 30 used here is a lens-type LED manufactured by a transfer molding method. In the transfer molding method, for example, as shown in FIG. 3, mounting and wire bonding of the semiconductor light emitting element 31 are performed in a cavity 43 (shaping chamber) formed between an upper mold 41 and a lower mold 42. The finished lead or lead frame 32 is placed in advance, and a liquid light-transmissive material (for example, a transparent epoxy resin) 33 is injected into the lead or lead frame 32 and then thermally cured, so that the semiconductor light-emitting element 31 is turned into the light-transmissive material 3.
3 refers to a method of manufacturing a light emitting diode (LED) sealed in. Note that the liquid light transmitting material can be injected into the cavity 43 along the lead frame 32.

In the LED 30 manufactured by the method shown in FIG. 3, a pair of leads 32 electrically connected to the light emitting element 31 sealed in the light transmissive material 33 extend from the light transmissive material portion in the left-right horizontal direction ( That is, a direction substantially orthogonal to the central axis line Z)
It looks like it extends to Further, the hemispherical light transmitting material portion covering the light emitting element 31 functions as a kind of condenser lens.

Each LED 30 is mounted on the surface of the substrate 15 (a power supply pattern (not shown) is formed in advance) using, for example, cream solder. In this case, the surface mounting means that cream solder is raised on the power supply pattern exposed on the substrate 15 and L
Each lead 32 extending from the ED 30 is embedded, and then the entire substrate is heated in a reflow oven to thermally cure the cream solder, thereby achieving electrical connection between the lead 32 and the power supply pattern and fixing the LED 30 to the substrate 15. That means.

As shown in FIG. 2, the plurality of optical substrates 2
Each of the 0s has a plane square shape. The optical substrates 20 are arranged adjacent to each other in front, rear, left and right, and the planar shape and the occupied area of the group of optical substrates 20 obtained as a result of the adjacent arrangement are the same as the planar shape of the single substrate 15 and the occupied area thereof. Almost correspond. That is, each optical base 20 is designed as a divided piece that can form a group of optical bases 20 having the same shape and the same size as the substrate 15 in plan view by combining a plurality of the optical bases 20 in a predetermined arrangement method. I have. In the first embodiment, one optical base 20 includes nine outer lenses 25 arranged in three rows and three rows. In the square area of the substrate 15 corresponding to the one piece of the optical base 20, nine LEDs 30 arranged in three rows and three rows of grid points are provided.
D30 and the outer lens 25 of the optical base 20 are in one-to-one correspondence.
There is a correspondence.

Each outer lens 25 has a corresponding LED
A convex lens shape is formed such that the light from the lens 30 is refracted and transmitted as parallel light parallel to the central axis Z. Of course, the orientation of the transmitted light can be arbitrarily adjusted by appropriately changing the shape of the convex lens and the optical characteristics of the outer lens 25. In order to make the light-collecting effect of the outer lens 25 effective and to secure a sufficient mounting density on the substrate 15, the plane area of the outer lens 25 should be four times the area of the radiation surface of the corresponding LED 30. It is preferable to set the above.

According to the first embodiment, the following effects can be obtained. LED 30 manufactured by transfer molding method
Has a high positional accuracy between the light emitting element 31 and the hemispherical lens portion of the light transmitting material covering the light emitting element 31. That is, LED
The central axis of the lens portion 30 and the central axis of the radiated light emitted from the light emitting element 31 match well. Therefore, LED3
0 itself has excellent light distribution characteristics.

In addition, in the LED 30 manufactured by the transfer molding method, since the leads 32 extend in a direction substantially perpendicular to the central axis Z of the LED 30, the surface mounting on the substrate 15 can be easily performed. High-density mounting is also possible. Therefore, the LED 3 on the substrate 15
The arrangement accuracy of 0 is increased, and the light distribution characteristics of the entire light source device are improved.

The light emitted from the light emitting element 31 of each LED 30 goes to the outside through two-stage light distribution control of light distribution control by the hemispherical lens portion of the LED 30 and light distribution control by the corresponding outer lens 25. Light is emitted. Therefore, it is not necessary to forcibly increase the directivity of the hemispherical lens portion of the LED 30. That is, generally, when the directivity of light of the lens-type LED itself is forcibly strengthened, the external radiation efficiency of light of the LED alone tends to decrease. In contrast,
In the present embodiment, it is not necessary to forcibly increase the directivity of light at the LED 30 and the light distribution control can be complemented by the outer lens 25, so that the external radiation efficiency of the entire light source device is improved. In addition, since the light distribution is controlled in two stages, it is easy to provide the light source device with desired light distribution characteristics.

Since the light distribution control of each LED 30 can be complemented by the outer lens 25, each LED 30 can be a small and independent resin product. Then, each of them is surface-mounted on the substrate 15. Therefore, compared to the case where an LED having a large resin lens is used,
At 0, thermal expansion and thermal contraction of the resin based on heating in the reflow furnace and subsequent cooling can be suppressed to a small value. Therefore, in the LED 30, the risk of disconnection of the bonding wire due to thermal expansion and contraction of the resin can be reduced.

Since the LEDs 30 are surface-mounted on the substrate 15, automatic mounting by an automatic machine is possible while increasing the mounting density per unit area, and the mounting height and the mounting angle of the LEDs 30 are substantially determined based on the substrate 15. Can be evenly aligned. In addition, one optical base 20 includes nine outer lenses 25 corresponding to the nine LEDs 30 on the substrate 15, and a single optical base 20 group formed by arranging the optical bases 20 adjacent to each other is a single optical base. Substrate 1
5. That is, since the relative positional relationship between the individual outer lenses 25 provided on one optical base 20 is determined for each optical base, if the adjacent arrangement relation between these optical bases 20 is accurately defined,
The LEDs 30 on the substrate 15 and the outer lenses 25 on the optical base 20 group side can be accurately positioned in a one-to-one correspondence. Therefore, the light emitted from each LED 30 can be controlled as desired by the corresponding outer lens 25, and the optical characteristics of the entire light source device can be made closer to the theoretical characteristics.

As described above, the LED 30 with respect to the substrate 15
Of the light source device and the efficient mass production of the light source device while improving the light distribution characteristics of the light source device by the synergistic effect of the adoption of the surface mounting and the configuration of integrating the nine outer lenses 25 into one optical base 20. Work time and labor).

(Second Embodiment) FIG. 4 shows a light source device according to a second embodiment that can be used, for example, as a light source for illumination. The light source device includes a single transparent substrate 14 and the substrate 14.
And a plurality of optical substrates 20 arranged at a predetermined distance from each other. Each of the optical bases 20 is an integrated body in which a plurality of reflective concave surfaces 24 as optical means are collectively formed.

The substrate 14 is made of a light-transmitting material, and a power supply pattern (not shown) is formed on the lower surface of the substrate 14 (the surface facing each optical base 20) by screen printing.
A plurality of LEDs 30 are surface-mounted on the power supply pattern. As in the first embodiment, the LEDs 30 are arranged such that the center axis Z of each LED 30 occupies a lattice point position.

The LED 30 used in this embodiment is also manufactured by the transfer molding method. Each LED
Reference numeral 30 has a hemispherical light emitting section 34, and a semiconductor light emitting element (not shown) is located at the center of the light emitting section 34. Since all the light rays emitted from the light emitting element are incident on the surface of the hemispherical part 34 at right angles, they do not refract when going out of the hemispherical part surface.

The fact that each of the optical substrates 20 has a planar square shape, and that the optical substrates 20 obtained by arranging them in front, rear, left and right are arranged at a predetermined distance from the single substrate 14. , And is the same as the first embodiment. The difference from the first embodiment is that a plurality of reflection concave surfaces 24 are formed on each optical base 20 as optical means corresponding to each LED 30 on the substrate 14 on a one-to-one basis.

As in the first embodiment, one optical base 20 has nine reflecting concave surfaces 24 arranged in three rows and three rows. Each reflecting concave surface 24 of the present embodiment is provided around the central axis Z of the corresponding LED 30.
It is formed along a paraboloid of revolution obtained by rotating a parabola whose focal point is 30 light emission centers. For this reason, when the light emitted from the LED 30 at the focal position of the paraboloid of revolution is reflected by the reflective concave surface 24, the reflected light is directed to the substrate 14 as parallel light parallel to the central axis Z. of course,
The orientation of the reflected light may be changed by adopting another reflection surface shape. In addition, the reflective concave surface 24 can be provided by mirror-finishing the metal surface or by forming a metal film by physical or chemical vapor deposition.

In the present embodiment, the separation length between the substrate 14 and the group of optical substrates 20 is set such that the hemispherical light-emitting portion 34 of each LED 30 is included in the area inside the concave portion 22 having the reflective concave surface 24 as the inner wall surface. Have been. Therefore, light emitted from each LED 30 in the lateral direction (horizontal direction) is also received by the reflection concave surface 24 and is effectively projected to the outside.

According to the second embodiment, the following effects can be obtained. As in the first embodiment, by adopting the transfer molding method, the light distribution characteristics of the LED 30 itself can be improved, surface mounting by an automatic machine can be performed, and the light distribution characteristics of the entire light source device can be efficiently improved. Excellent effects such as mass production can be obtained.

The separation length between the substrate 14 and the group of optical substrates 20 is set such that the hemispherical light-emitting portion 34 of the LED 30 is included in the area inside the concave portion 22 of the optical substrate 20, and L
Almost all the light emitted by the ED 30 can be externally radiated by controlling the reflection on the reflective concave surface 24. Therefore, the external radiation efficiency of light of the light source device can be improved. In the present embodiment, the surface mounting of the LEDs 30 on the substrate 14 facilitates the close arrangement of the substrate 14 and the group of optical substrates 20.

(Third Embodiment) FIGS. 5 to 9 show a light source device according to a third embodiment used as a light source of a signal lamp for a traffic light. As shown in FIGS. 5 to 7, the light source device includes a single substrate 10 and a plurality of optical substrates 20 facing the substrate 10 at a predetermined interval. Optical substrate 20
Are integrally formed by integrally forming a plurality of reflection concave surfaces 21 as optical means.

A power supply pattern (not shown) is formed on the lower surface (back surface) of the substrate 10 by screen printing, and a plurality of LEDs 30 are surface-mounted on the power supply pattern using cream solder. These LEDs 30
As shown in FIGS. 5 and 6, each central axis Z is arranged so as to occupy a lattice point position. The LEDs 30 used in the present embodiment are also manufactured by the transfer molding method. As shown in FIG. 8, each LED 30 is an LED having a hemispherical light emitting portion 34 similar to the second embodiment.

As shown in FIG. 6, each of the plurality of optical substrates 20 has a planar square shape. These optical substrates 20
Are arranged adjacent to each other in front, rear, left and right, and the planar shape and the occupied area of the group of optical substrates 20 obtained as a result of the adjacent arrangement substantially correspond to the planar shape of the single substrate 10 and the occupied area thereof. That is, each optical base 20 is designed as a divided piece that can form a group of optical bases 20 having the same shape and the same size as the substrate 10 when viewed two-dimensionally by combining a plurality of optical bases 20 in a predetermined arrangement method. I have.

As shown in FIGS. 5 and 6, the number of the LEDs 30 on the substrate 10 facing the one piece of the optical base 20 is nine, and the nine LEDs 30 are formed in a square shape facing the one piece of the optical base 20. The grid points are arranged in three columns and three rows in a region (indicated by a chain line in FIG. 5). On the upper surface side (the side facing the substrate 10) of each optical base 20, nine reflecting concave surfaces 21 corresponding to the nine LEDs 30 controlled by the optical base 20, respectively, are provided.

FIG. 8 shows one reflective concave surface 21 and the corresponding LED 30 and substrate 10 in an enlarged manner. FIG.
As shown in FIG.
An annular reflective concave surface 21 surrounding the central axis Z of the lens is formed. The reflecting concave surface 21 has an elliptical arc (that is, the center point P1) that is drawn with the LED 30 as a first focal point and one point of the condensing region D existing in the radial sectional plane as a second focal point in one radial section of the central axis Z. Is set to a three-dimensional shape along the spheroid obtained when the outer peripheral point P2 is rotated about the central axis Z. In other words, the aggregate around the central axis Z of the curve between P1 and P2 constitutes one three-dimensional concave concave surface 21. The reflection concave surface 21 is approximately 2π (stra
d) has a solid angle.

In the present embodiment, the distance between the substrate 10 and the group of optical substrates 20 is set such that the hemispherical light-emitting portion 34 of the LED 30 is included in the inner region of the concave portion 22 having each reflective concave surface 21 as an inner wall surface. Length is set. in this way,
Since the entire hemispherical light emitting portion 34 is completely accommodated in the inner region of the concave portion 22, almost all of the light emitted from the light emitting element located at the center of the hemispherical light emitting portion 34 reaches the reflective concave surface 21 and there. Change direction by being reflected.

As described above, the reflecting concave surface 21 has the LED 30 as a first focal point in one radial section of the central axis Z,
In addition, it is set to a three-dimensional shape obtained when an elliptical arc drawn with one point of the condensing area D as the second focal point is rotated around the central axis Z. For this reason, as shown in FIG.
The light reflected from the reflective concave surface 21 is shifted from the center point P1 to the outer edge point P.
No matter which reflection point Px on the curve up to 2 is reflected, an annular condensing area D (radius R
Focused on d).

As shown in FIG. 5, FIG. 7 and FIG.
0, the optical aperture 1 having a width W set along an arc (radius Rd) centered on the central axis Z of each reflection concave surface 21.
1 is formed to penetrate a plurality. The radius of the circular arc used as a reference for setting each optical opening 11 matches the radius Rd of the annular light-collecting region D. Then, the optical base 20 is placed such that the annular light-collecting region D is included in the arc-shaped optical opening 11 (that is, the optical opening 11 and the annular light-collecting region D substantially overlap with each other). The distance between the substrate and the substrate 10 is set.

The substrate 10 is made of a light-shielding material, and the portion other than the optical opening 11 functions as a light-shielding portion or a light-shielding plate portion. It is preferable that the front surface and the back surface of the substrate 10 are colored black, and the light-shielding portion or the light-shielding plate portion that is colored black absorbs light impinging on the light or diffuses light in a state of being greatly attenuated.

Each optical opening 11 is not a complete ring, but a connecting portion 12 for connecting a light shielding portion inside the optical opening 11 and a light shielding plate portion outside the optical opening 11 to a part of the annular region.
Is formed in an incomplete ring shape. This connecting part 12
Functions as a support member for supporting the inner light shielding portion on the outer light shielding plate portion. In addition, the back surface of the connecting portion 12 provides a communication path for passing a power supply line or a power supply pattern connecting the LED 30 and a power supply.

This light source device is used, for example, as a light source in each of three signal lamps constituting the traffic signal shown in FIG. When the signal lamp is turned on, the light emitted from each LED 30 is reflected by the corresponding reflective concave surface 21 and is focused on an annular light collecting area D set in the optical opening 11 of the substrate 10. After passing through the light converging region D, the collected light is emitted externally while diverging in the extending direction of each optical path. At this time, when viewed microscopically, each arc-shaped optical opening 11 is
It appears to be shining like a band in the color of the light emitted from it. When the signal light is observed from a distance, the entire front side of the signal light appears to be a uniform circle with the same color as the emission color of the LED 30.

On the other hand, when the signal lamp is turned off, the entire front side of the signal lamp looks clear black. This is because even when external light (for example, west sun) is irradiated on the surface of the substrate 10, most of the light is absorbed or attenuated by the substrate 10. Even if part of the external light enters the reflection concave surface 21 inside the device through the optical opening 11 of the substrate 10, the incident light is reflected by the LED 30 through the reflection concave surface 21.
, And then diffusely reflected there. Most of the incident light reaches the back surface of the substrate 10 while being repeatedly reflected inside the light source device, and is absorbed or attenuated there. For this reason, almost no outside light escapes to the outside of the light source device again through the optical opening 11 while maintaining the amount of energy when entering the light source device. As a result, in this signal light, dark noise does not appear even when the light is turned off, and the contrast between the light and the light is high.

According to the third embodiment, the following effects can be obtained. As in the first and second embodiments, the transfer molding method is used to improve the light distribution characteristics of the LED 30 itself, to enable surface mounting by an automatic machine, and to improve the light distribution characteristics of the entire light source device. In addition, excellent effects such as efficient mass production can be obtained.

The arrangement of the LEDs 30 and the setting of the shape of the reflection concave surface 21 as described above allow the LED 3
Almost all of the light emitted from 0 is received and reflected by the reflective concave surface 21. Then, the reflected light therefrom is projected outside through the light converging area D and the optical opening 11 without being interrupted on the way. That is, since almost all the light emitted from the LED 30 is effectively used, the external radiation efficiency of the light is extremely high. In general, in the case of a light source using a semiconductor light emitting element such as an LED, a small amount of light often poses a problem. However, the light source device of the present embodiment has an extremely high external radiation efficiency of light, Can be sufficiently compensated for.

Since the light source device has an extremely high external radiation efficiency as described above, even if the LED 30 to be used is downsized, no problem such as a reduction in apparent brightness occurs. Therefore, the size of the LED 30 to be used can be made smaller than a conventional general-purpose φ5 mm LED made by potting mold.

In general, when an LED manufactured by the transfer molding method is soldered to a substrate with cream solder and then the solder is thermally cured through a reflow furnace,
When the size of the LED is equal to or larger than the φ5 mm size, there is a disadvantage that the expansion and contraction of the resin due to the heat history easily breaks the wire inside the LED. In this regard, in the present embodiment,
Since the LED 30 can be conveniently reduced in size, it is possible to use an LED 30 smaller than the φ5 mm size manufactured by the transfer molding method. Therefore,
The above-mentioned drawbacks do not become apparent and do not cause any practical problems.

(Modification) Each of the above embodiments may be modified as follows. The number of optical means in each optical base 20 is not limited to nine, and one optical base 20 may be provided with a plurality of arbitrary optical means. The method of arranging the plurality of optical units in each optical base 20 is not limited to three rows and three rows, and the number of rows and columns may be arbitrarily selected.

In the above embodiments, the substrates 10, 14 and 15 are single substrates. However, as in the case of the optical base 20, the substrate may be composed of a plurality of divided pieces. In this case, it is preferable that the divided pieces of the substrate and the optical base 20 corresponding to each other have the same shape and the same size.

The form of the optical substrate 20 (and / or the divided pieces of the substrate) is not limited to a square plane, and may be, for example, a hexagonal plane or a rhombus plane. However, in order to ensure regular adjacent arrangement, it is preferable that the shape be a planar polygonal shape.

L in the above second and third embodiments
The ED 30 may be changed to a lens-type LED that can deflect light emitted from the semiconductor light emitting element in a specific direction. Further, the LED 30 may be of a type in which the light emitting element 31 is exposed naked without being sealed with a light transmitting material such as a transparent resin.

The optical opening 11 of the substrate 10 in the third embodiment may be formed of a light-transmitting solid material corresponding to the shape of the optical opening instead of the through hole. Alternatively, the substrate 10 is formed of a light-transmitting plate (eg, a glass plate), and an opaque light-shielding layer is printed on the surface to form the light-shielding portion and the light-shielding plate portion, while the remaining non-printed portion is An annular or arcuate optical opening 11 filled with a light transmitting material may function.

In the third embodiment, the reflecting concave surface 21
Was assumed to have a smoothly continuous concave shape.
It is not necessary for the concave surface to be a continuously smooth concave surface as long as the surface configuration converges the light reflected by the concave surface to a specific light-collecting region D. For example, a concave polyhedron optically equivalent to the reflective concave surface 21 may be formed by arranging an extremely large number of minute planes while slightly changing the angle of each minute plane. Such a concave polyhedron is also included in the category of “reflective concave surface” in the present specification.

The reflection concave surfaces 21 and 24 are formed by forming a part of a curve such as an arc, a parabola, a cycloid curve, or a spiral curve which approximates a reflection curve between the center point P1 and the outer edge point P2 around the center axis Z. It may be changed to a rotating curved surface obtained by rotation.

The points of the technical idea which are further grasped from the above embodiments and modified examples are listed below. The optical substrate according to any one of claims 5 to 7, wherein the optical base is formed with a concave portion in which the reflective concave surface forms an inner wall surface, and a light emitting portion of the light emitting diode is included in an inner region of the concave portion. Be done.

A light source constituting unit for constituting a light source device, wherein a substrate on which a plurality of light emitting diodes are surface-mounted and optical means arranged in a light emitting direction of a light emitting element mounted on the substrate A plurality of optical means respectively corresponding to the respective light emitting diodes corresponding to the optical means group.

[0076]

As described above in detail, according to the present invention, a plurality of light emitting diodes are surface-mounted on a substrate;
The synergistic effect of integrating the optical means corresponding to each light emitting diode as an optical base can improve or stabilize the light distribution characteristics of the entire light source device and increase the productivity of the light source device.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view (a longitudinal sectional view taken along line 1-1 in FIG. 2) of a light source device according to a first embodiment.

FIG. 2 is a partial plan view of an optical base group in the light source device of the first embodiment.

FIG. 3 is a schematic sectional view showing an example of a transfer mold.

FIG. 4 is a longitudinal sectional view corresponding to FIG. 1 in a light source device according to a second embodiment.

FIG. 5 is a partial plan view of a substrate in a light source device according to a third embodiment.

FIG. 6 is a partial plan view of an optical base group in the light source device according to the third embodiment.

FIG. 7 is a longitudinal sectional view taken along line 7-7 in FIGS. 5 and 6;

FIG. 8 is an enlarged sectional view of a part of FIG. 7;

FIG. 9 is a front view of a traffic light incorporating the light source device according to the third embodiment.

FIG. 10 is a sectional view of a conventional light source device and a part thereof.

FIG. 11 shows a lens LE using a potting mold.
Sectional drawing regarding manufacture of D.

[Explanation of symbols]

10: substrate, 11: optical opening, 14, 15: substrate,
Reference numeral 20: optical substrate (optical means group), 21, 24: reflective concave surface (reflective surface and optical means), 25: outer lens (optical means), 30: light emitting diode (LED), 31: light emitting element, 33: transparent resin (Light transmissive material), D: condensing area, Z: central axis.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Toshio Yamaguchi 1 Ochiai Ogata, Kasuga-cho, Nishi-Kasugai-gun, Aichi F-term (reference) 5F041 AA06 AA31 CA67 DA43 DB01 DB09 DC07 EE16 EE23 FF06 FF11

Claims (8)

[Claims] 1. A light emitting device comprising: a plurality of light emitting diodes each having a light emitting element encapsulated in a light transmitting material; and one or more substrates on which the plurality of light emitting diodes are surface-mounted. A light source device, wherein a plurality of optical means are respectively arranged in an integrated state corresponding to the light emitting diodes in the emission direction. 2. The light source device according to claim 1, wherein said optical means comprises a lens. 3. The light source device according to claim 1, wherein said optical means comprises a reflection surface for controlling reflection of incident light. 4. The device according to claim 1, wherein the optical means has a plane area at least four times as large as the area of the emission surface of the light emitting diode corresponding to the optical means. Light source device. 5. The reflecting surface is a substantially annular reflecting concave surface surrounding the central axis of the corresponding light emitting diode, and reflects the reflected light of the light from the light emitting diode into an annular collection centered on the central axis. The light source device according to claim 3, wherein the light source device has a concave shape so as to converge light in the light area. 6. The reflection concave surface has a shape obtained by rotating an elliptical arc having the light-emitting diode as another focal point around the center axis, with one radial center point of the light-collecting region as one focal point. The light source device according to claim 5, wherein: 7. The substrate is provided with a plurality of optical openings along an arc centered on a central axis for each of the light emitting diodes mounted on the substrate, and each of the optical openings has substantially 7. The light source device according to claim 5, wherein the annular light-collecting region is set to overlap, and a portion other than the optical opening in the substrate is a light-shielding portion. 8. 8. A step of preparing a plurality of optical means groups in which a plurality of optical means are integrally provided; and providing a plurality of light emitting diodes having light emitting elements sealed in a light transmitting material on a substrate. Surface mounting step, by arranging the plurality of optical means groups adjacent to each other in the light emission direction of the light emitting diode, the light emitting diodes mounted on the substrate and the optical means of each optical base group And a method for manufacturing the light source device.