JP2679132B2 - LED linear light source - Google Patents

Description

The present invention relates to an LED linear light source using a light emitting diode as a light source.

[Conventional technology]

BACKGROUND ART Conventionally, in LED linear light sources using light emitting diodes as light sources, various structures have been devised in order to effectively radiate light emitted from the light emitting elements of each light emitting diode in the front direction. FIG. 13 shows a conventional structure using a lens and a reflector.
FIG. 14 is a schematic cross-sectional view of the LED linear light source, and FIG. In FIGS. 13 and 14, 1 is a light emitting element,
11 is an insulating substrate, 12 and 13 are circuit patterns, 14 is a wire,
Reference numeral 15 is a reflecting mirror made of a highly reflective resin material, and 16 is a cylindrical resin lens. A plurality of light emitting elements 1 arranged on the same straight line are densely mounted at equal intervals in the center of an insulating substrate 11, and are electrically connected by circuit patterns 12 and 13 and wires 14, respectively. Further, on the insulating substrate 11, along the light emitting elements 1 arranged in a straight line, reflecting mirrors 15 are provided on both side surfaces thereof, and a cylindrical resin lens 16 is provided on the reflecting mirrors 15.

According to the LED linear light source configured as described above, of the light emitted from the light emitting element 1, the light emitted in the upper direction directly passes through the lower end surface of the resin lens 16, and the directivity is strengthened by the lens effect. It is emitted to the outside. Further, the light emitted in the side direction is diffused and reflected by the reflecting mirror 15 made of a highly reflective resin material, and then radiated to the outside through the resin lens 16. Further, since the respective light emitting elements 1 are densely mounted on the same straight line, the irradiation surface has a uniform illuminance.

[Problems to be solved by the invention]

However, in the conventional LED linear light source, the light emitting element 1
The light emitted in the lateral direction is diffusely reflected by the reflecting mirror 15 formed of a highly reflective resin material, and therefore few of the light efficiently reach the lower end surface of the resin lens 16. Further, the light reflected by the reflecting mirror 15 and reaching the resin lens 16 has a limited incident angle to the lower end surface of the resin lens 16, so that few are emitted in the front direction. Therefore, in the conventional LED linear light source, most of the light diffusely reflected by the reflecting mirror 15 is the LED.
It does not contribute to the luminous intensity in the front direction of the linear light source, resulting in wasted light,
There was a drawback that the radiation efficiency of light in the front direction was poor.

Further, in the conventional LED linear light source, it is necessary to mount the light emitting elements 1 densely in order to obtain uniform irradiation light.
There is a drawback that the output of the light emitting element 1 is reduced due to heat generation during lighting, and the life of the light emitting element 1 is shortened.

The present invention has been made based on the above circumstances, it is possible to improve the irradiation efficiency of the light emitted from the light emitting element to the irradiation surface, and further, when the light emitting element is turned on, the output of the light emitting element is reduced due to heat generation or An object of the present invention is to provide an LED linear light source capable of preventing deterioration of a light emitting element.

[Means for solving the problem]

The LED linear light source of the present invention for achieving the above-mentioned object is a light emitting element, a lead portion for supplying electric power to the light emitting element, and the light emitting element provided facing the light emitting surface of the light emitting element. A concave reflecting surface that reflects the emitted light to form a focused light, an optical waveguide that converts the light focused by the concave reflecting surface into a linear light, and a space between the concave reflecting surface and the optical waveguide. And a light-transmissive material filling the space in which the light emitting element and the tip of the lead portion are arranged, the light emitted from the light emitting element is reflected by the concave reflection surface to be focused light, The focused light is converted into linear light by an optical waveguide and is emitted to the outside.

Further, a plurality of LED linear light sources having the above configuration may be combined with different emission wavelengths of the light emitting elements.

Further, it is preferable that the concave reflecting surface is formed in an elliptical shape.

Further, the optical waveguide may be one in which the entrances of a plurality of linear optical waveguides are formed in a bundle shape and the radiation openings are formed in a linear shape, and the planar optical waveguide is bonded to the radiation openings of the plurality of linear optical waveguides. Alternatively, the entrance of the planar optical waveguide may be formed in a circular shape and the radiation opening may be formed in a linear shape.

[Action]

According to the present invention, by the structure described above, power is supplied from the lead portion to the light emitting element, and the light emitted from the light emitting element is once reflected by the concave reflecting surface to be focused light, and the focused light is further converted into linear light by the optical waveguide. After conversion, it radiates to the outside.

Further, by combining a plurality of LED linear light sources with different emission wavelengths of the light emitting elements, it is possible to emit polychromatic light or mixed color light.

Further, by forming the concave reflecting surface in an elliptical shape, for example, a light emitting element is arranged at one of the focal points and an entrance of the optical waveguide is arranged in the vicinity of the other focal point, so that the light emitted by the light emitting element can be efficiently emitted. It can be well injected into the optical waveguide as focused light.

Further, as the optical waveguide, a plurality of linear optical waveguides in which the entrances are formed in a bundle shape and the emission openings are formed in a linear shape, or one in which a planar optical waveguide is joined to the emission openings of the plurality of linear optical waveguides is used. By using it, or by using a planar optical waveguide in which the entrance is formed in a circular shape and the emission opening is formed in a linear shape, it is possible to easily and reliably convert the focused light into linear light. When the planar optical waveguide is used as the optical waveguide, the radiated light emitted to the outside is made uniform by the planar optical waveguide.

〔Example〕

Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a first embodiment of the present invention.
FIG. 2 (a) is a schematic enlarged view of the entrance of the optical waveguide, and FIG. 2 (b) is a schematic partial enlarged view of the emission opening of the optical waveguide. FIG. 3 is an optical path diagram of light emitted from the light emitting element. 1 to 3, 1 is a light emitting element, 2 and 3 are lead frames for supplying electric power to the light emitting element 1, 4 is a wire, 5 is a light transmissive material, and 5a
Is an ellipsoidal reflecting surface that reflects and focuses the light emitted from the light emitting element 1, and 6 is an optical waveguide that is composed of a plurality of linear optical waveguides 6a and converts the focused light into linear light. The arrow indicates the optical path of the light emitted from the light emitting element 1.

The light emitting element 1 is mounted on one lead frame 2 and is electrically connected to the other lead frame 3 by a wire 4. In addition, the light emitting element 1 and the lead frame 2
The tip of 3 is molded with the light transmitting material 5.
The reflecting surface 5a is formed by forming a surface of the light transmissive material 5 facing the light emitting surface of the light emitting element 1 into an elliptical shape, and mirror-finishing the surface by plating or metal deposition. The linear optical waveguides 6a of the optical waveguide 6 are bound together in a bundle at an entrance 6b through which light enters as shown in FIG. 2 (a), and emit the light to the outside as shown in FIG. 2 (b). The radiation ports 6c are linearly arranged. The light emitting element 1 is arranged at one focus of the reflecting surface 5a formed in an elliptical shape, and the entrance 6b of the optical waveguide 6 is arranged near the other focus. The space between the entrance 6b and the reflecting surface 5a of the optical waveguide 6 is filled with the light transmissive material 5. Further, during plating or metal deposition for forming the reflecting surface 5a, the lead frames 2 and 3 are insulated from each other.

According to the above configuration, power is supplied to the light emitting element 1 by the lead frames 2 and 3 and the wires 4, and the light emitting element 1 emits light. Then, the light emitted from the light emitting element 1 is reflected by the reflecting surface 5a as shown by the arrow in FIG.
It is emitted to the entrance 6b of the optical waveguide 6, converted into linear light by the optical waveguide 6, and emitted to the irradiation surface 7. The diameter and the number of each linear optical waveguide 6a of the optical waveguide 6 to be used are appropriately selected according to the application.

The line width of the lead frames 2 and 3 can be easily set to 0.1 mm or less, and the area occupied by the light emitting element 1 is about
Since it is 0.4 mm × 0.4 mm, for example, the diameter of the reflecting surface 5a should be 5 m.
Even if m is set, the light emitting element 1 and the lead frames 2 and 3
Since the loss due to the shadow of about 3% is about 3%, there is no particular problem in terms of efficiency.

According to the present embodiment described above, since the light emitted from the light emitting element 1 can be efficiently injected into the optical waveguide 6 by the reflecting surface 5a and can be linearly emitted to the irradiation surface 7 by the optical waveguide 6, When the same number of light emitting elements as the LED linear light source is used, the illuminance of the irradiation surface 7 can be improved. Further, the same illuminance as that of the conventional LED linear light source can be obtained with a smaller number of light emitting elements than the number of light emitting elements used in the conventional LED linear light source.

Further, according to the above-described embodiment, since the light emitting element 1 is not densely mounted like the conventional LED linear light source, the output of the light emitting element 1 is reduced when the LED is turned on unlike the conventional LED linear light source. And the light emitting element 1 is not deteriorated.

Further, according to the present embodiment described above, the line width of the linear light can be reduced, so that when used as a light source for reading, the accuracy of reading can be improved.

Further, the space between the light emitting element 1 and the reflecting surface 5a and the space between the reflecting surface 5a and the entrance 6b of the optical waveguide 6 is filled with the light transmissive material 5, and since there is no air layer, the loss of light due to interface reflection is small. .

When a large number of LED linear light sources are arranged in the above embodiment, the light emitting element 1 may be arranged and connected to a transparent insulating circuit board, and a heat sink may be provided as necessary.

FIG. 4 is a schematic conceptual view of an LED linear light source that is a second embodiment of the present invention, FIG. 5 is a schematic enlarged view of a portion of its emission port, and FIG. 6 is a schematic portion showing a modification of the emission port. FIG. In the second embodiment shown in FIGS. 4 to 6 and other embodiments described below, those having the same functions as those of the first embodiment shown in FIGS. 1 to 3 are the same. The detailed description is omitted by attaching the reference numerals.

In FIGS. 4 to 6, 1a and 1b are, for example, light-emitting elements whose emission colors are red and yellow-green, 6d is a linear optical waveguide that emits red light, and 6e is a line that emits yellow-green light. Optical waveguide. In the second embodiment of the present invention, two sets of the LED linear light sources of the first embodiment are arranged, one light emitting element 1a emits red light, and the other light emitting element 1b emits yellow green light. Further, the emission port 6c is formed by alternately arranging the linear optical waveguides 6d for emitting red light and the linear optical waveguides 6e for emitting yellow green light as shown in FIG. In addition, radiation port
As for 6c, the linear optical waveguide 6d and the linear optical waveguide 6e may be arranged in parallel as shown in FIG.

According to the second embodiment, the light emitting element 1a and the light emitting element 1b are alternately turned on to provide a multicolor LED linear light source. Other operations and effects are the same as those of the first embodiment.
In the second embodiment described above, the LED of the first embodiment is used.
The case where two sets of linear light sources are arranged has been described, but three sets or more are arranged, for example, three sets each having a light emitting element whose emission wavelength is red, blue, and yellow are arranged, and three sets are arranged. You may make it light simultaneously and emit a white illumination light.

FIG. 7 is a schematic conceptual view of an LED linear light source according to a third embodiment of the present invention, FIG. 8 is a schematic partial enlarged view of a radiation port of the optical waveguide, and FIG. 9 is a linear optical waveguide and a planar shape. It is a figure which shows the radiation state of the light in the junction part with an optical waveguide. In FIGS. 7 to 9, 6f is a planar optical waveguide.

The third embodiment is a plurality of linear optical waveguides 6a of the first embodiment.
The planar optical waveguide 6f is joined to the tip of the. That is, the optical waveguide 6 of the third embodiment is a plurality of linear optical waveguides.
6a and the planar optical waveguide 6f are joined together. The planar optical waveguide 6f is an optical waveguide by providing a clad layer made of a low refractive index material on the side surface of a substantially sheet-shaped light transmissive high refractive index material.

The light emitted from each linear optical waveguide 6a does not spread in the direction vertical to the paper surface of FIG. 9, but spreads horizontally in the paper surface as shown in FIG. Therefore, even if the light transmitted by the linear optical waveguides 6a varies, the light is made uniform when passing through the planar optical waveguide 6f and emitted to the outside. Thus, according to the third embodiment, the linear optical waveguide
Since the planar optical waveguide 6f is provided at the tip of the linear optical waveguide 6a, the light emitted from the linear optical waveguide 6a spreads in the planar optical waveguide 6f, is homogenized, and is radiated to the outside. Other operations and effects are the same as those of the first embodiment. In the above embodiment, the case where the planar optical waveguide is joined to the optical waveguide of the first embodiment has been described, but the planar optical waveguide may be joined to the optical waveguide of the second embodiment. Thereby, uniform red light and yellow green light can be emitted.

FIG. 10 is a schematic conceptual view of an LED linear light source which is a fourth embodiment of the present invention, FIG. 11 (a) is a schematic enlarged view of the entrance of the optical waveguide, and FIG. 10 (b) is the optical waveguide. Fig. 12 is a schematic enlarged view of the emission port of Fig. 12, and Fig. 12 is an optical path diagram of the light emitted by the light emitting element.
FIG. 13 is a schematic diagram showing a modification thereof.

The fourth embodiment of the present invention is different from the first embodiment in that
The optical waveguide 6 is formed by the planar optical waveguide 6f.
The planar optical waveguide 6f may have a cladding layer formed by coating the side surface with a material having a low refractive index. Further, the planar optical waveguide 6f may have a curved shape instead of a flat shape.

In the LED linear light source of this embodiment, as shown in FIG. 12, the light emitted from the light emitting element 1 is reflected by the concave reflecting surface 5a to be focused and converted into linear light by the planar optical waveguide 6f. Radiate to the outside. The planar optical waveguide 6f used in the present embodiment is easy to form, and it is also possible to form the planar optical waveguide 6f at the same time when the light emitting element 1 is molded with the light transmissive material 5. Therefore, the LED linear light source of this embodiment can be easily mass-produced. Other operations and effects are the same as those of the first embodiment.

Further, as shown in FIG. 13, a structure in which a plurality of sets of the light emitting element 1 and the reflecting surface 5a are provided for one planar optical waveguide 6f may be adopted. As a result, LEDs with brightness according to the application
The linear light source can be easily manufactured.

In the first to fourth embodiments, the light emitting element 1
The lead portion that supplies power to the lead frame 2 is mainly
Although the case where the lead portion is composed of 3 and the wire 4 has been described, the present invention is not limited to this. For example, the lead portion may be a transparent glass substrate on which a stem or a fine line circuit is formed.

〔The invention's effect〕

As described above, according to the present invention, after the light emitted by the light emitting element is reflected by the concave reflecting surface and focused, it is converted into linear light by the optical waveguide. It is possible to provide an LED linear light source that can improve the irradiation efficiency of the above, and can prevent the reduction of the output of the light emitting element due to the heat generation of the light emitting element during lighting and the deterioration of the light emitting element.

[Brief description of the drawings]

FIG. 1 is a schematic conceptual view of an LED linear light source that is a first embodiment of the present invention, FIG. 2 (a) is a schematic enlarged view of an entrance of an optical waveguide thereof, and FIG. FIG. 3 is a schematic partially enlarged view of a radiation port of an optical waveguide, FIG. 3 is an optical path diagram of light emitted from the light emitting element, and FIG. 4 is a schematic conceptual diagram of an LED linear light source that is a second embodiment of the present invention. The figure shows a schematic enlarged view of the emission port,
FIG. 6 is a schematic partially enlarged view showing a modified example of the radiation port, FIG. 7 is a schematic conceptual diagram of an LED linear light source which is a third embodiment of the present invention, and FIG. 8 is a radiation port of the optical waveguide. FIG. 9 is a schematic enlarged view of a portion of FIG. 9, FIG. 9 is a diagram showing a light emission state at a joint portion between a linear optical waveguide and a planar optical waveguide, and FIG. 10 is an LED linear light source according to a fourth embodiment of the present invention. Schematic conceptual diagram of Fig. 11 (a)
Is a schematic enlarged view of the entrance of the optical waveguide, FIG. 12B is a schematic partial enlarged view of the exit of the optical waveguide, FIG. 12 is an optical path diagram of light emitted by the light emitting element, and FIG. 13 is a modification thereof. A schematic diagram showing an example, Fig. 14 shows a conventional LED using a lens and a reflector
FIG. 15 is a schematic perspective view of the linear light source, and FIG. 15 is a schematic BB sectional view thereof. 1 ... Light emitting element, 2.3 ... Lead frame, 4 ... Wire, 5 ... Light transmissive material, 5a ... Reflective surface, 6 ... Optical waveguide, 6a ... Linear optical waveguide, 6f ... Planar optical waveguide.

Claims (6)

(57) [Claims] 1. A light-emitting element, a lead portion for supplying electric power to the light-emitting element, and a concave reflection which is provided so as to face the light-emitting surface of the light-emitting element and reflects the light emitted by the light-emitting element into focused light. Surface, an optical waveguide for converting the light focused by the concave reflecting surface into linear light, a space between the concave reflecting surface and the optical waveguide, and the tip of the light emitting element and the lead portion And a light-transmissive material filling the space in which the portion is arranged, the light emitted from the light-emitting element is reflected by the concave reflecting surface to form focused light, and the focused light is converted into linear light by an optical waveguide. It is characterized in that it is configured to radiate to the outside
LED linear light source. 2. An LED linear light source obtained by combining a plurality of LED linear light sources according to claim 1 with different emission wavelengths of light emitting elements. 3. The LED linear light source according to claim 1, wherein the concave reflecting surface is formed into an elliptical shape. 4. The optical waveguide is composed of a plurality of linear optical waveguides, wherein the light entrance is formed into a bundle and the light exit is formed into a linear shape. LED linear light source according to any one of. 5. The optical waveguide comprises: a plurality of linear optical waveguides having a plurality of entrances formed in a bundle and a radiation opening formed in a line; and a planar optical waveguide joined to the radiation openings of the plurality of linear optical waveguides. The LED linear light source according to any one of claims 1 to 3, which is composed of 6. The LED linear shape according to claim 1, wherein the optical waveguide is a planar optical waveguide, the entrance of which is circular and the exit of which is linear. light source.