JP2002245806A - Led lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an LED lighting device which can irradiate over a wide-angle range with the use of an LED close to a point light source. SOLUTION: With the LED lighting device provided with a light-guide body of a cylindrical shape made of a transparent material and LED's located at least at one end of the light guide body and arranged so as to radiate light on the inside of the light guide body, a plurality of grooves with square cross section arranged at a suitable interval in the axis direction around the periphery face of the light guide body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LED lighting device having a large light-emitting area using an LED as a light source.

[0002]

2. Description of the Related Art Due to its characteristics, an LED shines at a spot without scattering light. For this reason, conventionally, LEDs are used for applications such as indicators and pilot lamps.
The main use was to display something by the lighting of the ED itself and to make the meaning recognized. As another use form of the LED, as described in Japanese Patent Application Laid-Open No. 9-163080, the LED is incorporated in a line light source device such as reading a facsimile original or erasing a latent image on a photosensitive drum in a PPC copying machine. Sometimes used. This known line light source device has a structure in which a lens is formed on a cylindrical transparent member having one end provided with a light source light intake portion and the other end provided with a reflecting surface by an isosceles triangular knurl cut.

[0003]

However, the light source device described in the above-mentioned publication generates substantially linear irradiation light which is wide in a predetermined direction and narrow in a direction perpendicular to the predetermined direction. However, the use form is limited to a special one such as facsimile document reading, and is not suitable for obtaining a lighting effect like a normal lamp.

An object of the present invention is to provide an LED lighting device which is different from a conventional light source device using an LED as a light source and is improved so as to irradiate light over a wide range.

[0005]

According to a first aspect of the present invention, there is provided a cylindrical light guide made of a light-transmitting material, and a light guide which is located on at least one end face of the light guide. An LED arranged to emit light therein, wherein the light guide has a plurality of grooves having a square cross section arranged at appropriate intervals along an axial direction on a peripheral surface thereof. It is characterized by doing. The invention described in claim 2 is characterized in that the groove is provided only within a range of an appropriate length from an end face where the LED is arranged. The invention according to claim 3 is characterized in that the interval between the grooves is wide at a portion near the end face where the LEDs are arranged, and is gradually reduced as the distance from the end face is increased.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings. In FIG. 1, reference numeral 1 denotes a cylindrical light guide, and 2 denotes an L provided in contact with both end surfaces of the light guide 1.
Indicates ED. This LED 2 is formed by molding a light emitting diode with a transparent resin and forming two lead wires 1 of the light emitting diode.
2 is a normal LED having a structure in which 2 is drawn out. Each LED 2 is arranged so that its light emitting optical axis coincides with the axis of the columnar light guide 1, and is fixed at that position by a holding mechanism (not shown). As LED2,
Gallium - phosphorus GaP-based green or red LED, gallium - arsenic - Although any LED such as phosphorus GaAs _X P _1-X-based red LED can be used, LED2 used in this embodiment, the diameter of 5mm Super bright white LE
D.

On the other hand, as shown in FIG. 2, the light guide 1 has a cylindrical shape made of a synthetic resin having good translucency, for example, a hard acrylic resin. A large number of grooves 11 are formed on the peripheral surface in a region of an appropriate length from one end surface. The end face facing the LED 2 is desirably finished as smooth as possible to prevent irregular reflection or refraction of light on this face. 3A and FIG.
As shown in (B), the light guide 1 has a rectangular cross section.
Extends along a plane perpendicular to the axis of the lens and over about one-half of its peripheral surface. The groove having such a shape can be easily formed by laser processing.

The interval between the grooves 11 may be constant in the axial direction of the light guide 1, but is preferably widest on the end face of the light guide 1, that is, on the side near the LED 2, and as the distance from the LED 2 increases, They are arranged so that they become narrower sequentially. The length of each groove 11 in the circumferential direction of the light guide 1 is also set to be the longest on the end face of the light guide 1, that is, on the side close to the LED 2, and to be gradually reduced as the distance from the LED 2 increases.

In the thus configured LED lighting apparatus, when each LED 2 receives a direct current and emits light, the light emitted from the LED 2 enters the inside of the light guide 1 from the end face thereof and is directed toward the opposite end. It proceeds, but part of it
Is refracted on the side surface of the light guide 1 and is emitted to the outside of the light guide 1. Since the groove 11 is formed over a range of an appropriate length in the length direction of the light guide 1, light from the plurality of grooves 11 is radiated to the outside in this region. Further, since the interval between the adjacent grooves 11 is set to be wide in a portion close to the LED 2 and narrow as the distance from the LED 2 increases, light refraction by the groove 11 is small at a position where the amount of light from the LED 2 is large. Since the number of grooves 11 increases as the amount of light decreases as the distance from LED 2 decreases, uniform illuminance can be obtained over the entire length of light guide 1.

In the above embodiment, since the groove 11 is formed to have a length approximately half the circumference of the cylindrical light guide 1, it is illuminated with the light from the light guide 1. The light guide 1
However, if the groove 11 is formed in an annular shape so as to extend over the entire peripheral surface of the light guide 1, light is omnidirectional. Irradiation is possible.

FIG. 4 shows another embodiment of the present invention.
In this example, the LED 2 is provided only at one end of the light guide 1, and the groove 11 formed on the peripheral surface of the light guide 1
It is only provided in an appropriate range from only the end on the side where 2 is provided. The LED lighting device of this configuration is
Suitable for applications where the area to be illuminated is relatively small. As described above, the LED lighting device of the present invention does not generate heat, and can obtain relatively high illuminance at low voltage and low current.
It can be advantageously used for the following applications.

When used for outdoor lighting such as signboards and road signs, there is no need to replace light bulbs, so that it is possible to realize a product that requires only installation and no maintenance. In addition, when combined with a solar panel, a power supply is not required, and as a power-saving lighting, it is a lighting that considers the global environment and can also be used as lighting on forest roads without a power supply. Since it does not generate heat, it can be used as a light source in refrigerators and freezers. Also, unlike a cold-cathode tube, it does not become dark when the temperature drops. It can be embedded in display counters and used for displays. Since there is no need to change the light bulb, it can be freely embedded anywhere. In this case, it may be used in combination with other colors such as red and green. If it is used for facility lighting footlights, guide lights such as stairs, emergency lights, etc., it can be turned on for a long time with a standby power supply even during a power outage. Since it has a long service life and requires no maintenance, it can be embedded in buildings. When applied to a study desk lamp, etc., since there is no flicker like a fluorescent lamp, it is easy on the eyes and hardly causes myopia. Utilizing features such as a small and lightweight recognition light, it can be incorporated into diving equipment, for example, to be used for recognition during night diving, or for use as a recognition light for night jogging.

[0013]

As described above, in the LED lighting device of the present invention, the LED is provided so as to face at least one end face of the columnar light guide having a groove at an appropriate position on the peripheral surface. It is possible to refract light from an LED close to a point light source at a plurality of points in the axial direction of the light guide and emit the light within a desired angle range. This makes it possible to maximize the advantages of the LED over other light sources.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an LED lighting device according to an embodiment of the present invention.

FIG. 2 is a side view of the LED lighting device shown in FIG.

3A and 3B are cross-sectional views of the light guide of the LED lighting device shown in FIG. 1, wherein FIG. 3A is a cross-sectional view, and FIG. 3B is a cross-sectional view taken along line BB 'of FIG.

FIG. 4 is a perspective view showing an LED lighting device according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light guide 2 LED 11 Groove 12 Lead wire

Claims (3)

[Claims] 1. A cylindrical light guide made of a translucent material,
An LED located on at least one end face of the light guide and arranged to emit light inside the light guide, wherein the light guide has a peripheral surface along an axial direction. An LED lighting device comprising a plurality of grooves having a square cross section and arranged at appropriate intervals. 2. The LED lighting device according to claim 1, wherein the groove is provided only within a range of an appropriate length from an end surface on which the LED is arranged. 3. The device according to claim 1, wherein an interval between the grooves is wide at a portion near an end face where the LEDs are arranged, and becomes gradually narrower as the distance from the end face is increased. LED lighting device.