KR20190045431A - Lighting apparatus of LED - Google Patents

Abstract

The present invention relates to a planar lighting device for a street lamp, which can simplify a structure using an LED light source and a light guide member and efficiently control light characteristics such as an emitted light amount and an emission angle. The LED planar lighting device of the present invention comprises: a frame having an open front and a receiving space formed therein; a light source installed at one side of the receiving space of the frame and providing light to the receiving space; a plurality of light guide plates installed in the receiving space at the front of the light source as a plate-like plate and having a light incident surface on a side of the plate facing the light source, a reflective surface of a plate back surface, and a light-emitting surface at the front of the plate, wherein a linear light output pattern cut out in a slit shape in a direction perpendicular to a direction in which light is incident is formed on the light-emitting surface at a predetermined interval in the light incidence direction; and a reflective member interposed between the back surface of the light guide plate and the bottom surface of the frame.

Description

{Lighting apparatus of LED}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface illuminator, and more particularly, to a surface illuminator for a street lamp that can simplify a structure using an LED light source and a light guiding member and efficiently control light characteristics such as an emitted light amount and an outgoing angle .

Various types of lighting devices are used as devices for providing light at night or indoors or for illuminating objects. In particular, lighting devices that use LED (Light Emitting Diode) as a light source have lower power consumption than incandescent lamps and fluorescent lamps, which not only saves energy but also maintains robustness and longevity unlike conventional light sources. There is an advantage advantageous in terms of

On the other hand, a streetlight is installed for safety on the road, and it is installed in a place requiring illumination such as a road in a residential district as well as a highway or a city area, and a structure or a method suitable for the place is installed. In recent years, LEDs that have a long life span in such street lamps and minimize power consumption are used as light sources.

1 is a cross-sectional view showing a main configuration of a conventional surface lighting apparatus.

Referring to the drawings, an LED surface illuminator includes a frame 1, an LED light source 2 mounted on the substrate 2a with a plurality of LED elements 2b mounted on at least one side of the frame 1, A light guide plate 3 installed inside the frame 1 to absorb light of the light source 2, a reflection member 4 provided below the light guide plate, and an optical sheet 5 provided on the light guide plate.

The planar illumination device 10 having the above-described structure converts a large amount of light incident from the LED element 2b into a planar light source while being totally reflected in the light guide plate 3 and is emitted through the optical sheet 5, Provides light of the light source. At this time, a dot-shaped light pattern 3a for improving brightness is formed on the back surface of the light guide plate 3 through scattering and irregular reflection of light, and the optical sheet 5 has a diffusion sheet and a prism sheet .

Therefore, since the LED surface illuminating device according to the related art has to form a fine pattern on the back surface of the light guide plate, it is difficult to process the light guide plate according to processing of the pattern having high design difficulty. In addition, the conventional LED surface illuminating device has a problem that the manufacturing cost is increased because a diffusion sheet and a prism sheet are necessarily provided.

In addition, a surface illuminating device used as a street light is concentrated in a specific area to illuminate the light, but the surface illuminating device using the diffusion sheet and the prism sheet has such a disadvantage that it is difficult to control the illuminated area.

Korean Patent Laid-Open Publication No. 10-2013-0050455 (published May 21,

SUMMARY OF THE INVENTION The present invention has been proposed in order to solve the problems described above, and it is an object of the present invention to provide a planar light source with a combination of an LED light source and a light guide plate, And it is an object of the present invention to provide a planar illumination device capable of reducing a manufacturing cost by removing a prism sheet.

It is another object of the present invention to provide a street lighting device for a streetlight which can provide light of a linear light source using a light guide plate and can easily control an illumination area.

According to an aspect of the present invention, there is provided an LED surface illuminator comprising: a frame having a front surface opened and a receiving space formed therein; A light source installed at one side of the receiving space of the frame and providing light to the receiving space; A plate-shaped plate provided in the receiving space at a front surface of the light source and having a light incident surface on a side of the plate facing the light source, a reflection surface of the plate rear surface, and a light output surface on the front surface of the plate, A light guide plate in which a plurality of linear light exit patterns, which are cut in a slit shape in a direction perpendicular to a direction in which light is incident, are formed at predetermined intervals in a light incidence direction; And a reflective member interposed between a back surface of the light guide plate and a bottom surface of the frame.

Here, the light output pattern has a slant shape inclining in a direction away from the light incidence surface, and is varied so as to be deeper as the light is farther from the light incidence surface.

It is preferable that the light output pattern has an angle of inclination (θ) of 20 ° to 70 ° with respect to the surface of the light exit surface, a width (w) of the pattern is 0.01 mm to 1 mm, mm to 50 mm.

According to the present invention having the above-described structure, fabrication process is facilitated since high-level optical pattern processing is not required for the light guide plate, and the diffusion sheet and the prism sheet are removed, thereby reducing manufacturing cost.

Further, the present invention can embellish the appearance of the surface lighting apparatus by realizing the light of the linear light source by the combination of the LED light source and the light guide plate.

Further, the present invention can easily design a region in which light is illuminated by controlling the pattern shape.

1 is a cross-sectional view showing a main configuration of a conventional surface lighting apparatus,
2 is a cross-sectional view showing a main configuration of a planar illumination device according to an embodiment of the present invention,
3 is a perspective view illustrating an LED light source and a light guide plate,
FIG. 4 is an enlarged cross-sectional view showing in detail the light extraction pattern of the light guide plate, which is the main part of FIG. 2;

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a perspective view showing an LED light source and a light guide plate as main parts of FIG. 2, FIG. 4 is a sectional view of a light guide plate according to an embodiment of the present invention, 5 is an enlarged cross-sectional view showing the pattern in detail.

2, a planar illumination apparatus 100 according to an embodiment of the present invention includes a frame 110 having a front surface opened and forming an accommodation space therein, an LED 110 installed in a space inside the frame, A light guide plate 130 disposed in a space of the frame 110 in front of the LED light source 120 and a reflective member 140 disposed on the back surface of the light guide plate 130.

Specifically, the frame 110 constitutes an outer case of the surface light source device 100, and a metal plate may be formed by extrusion molding. The frame 110 may have a hexahedron shape having a front surface opened and a receiving space formed therein and has a fastening structure in which the LED light source 120, the light guide plate 130, and the reflecting member 140 can be coupled, A control module (not shown) for driving the lighting device can be coupled.

The LED light source 120 is a light source of a surface illuminator that is disposed at one side of the frame 110 to provide light into the light guide plate 130. The LED light source 120 includes a plurality of LED elements 120b mounted on a substrate 120a, . ≪ / RTI > That is, the surface illuminator of the present invention constitutes an edge type illumination device in which the LED light source 120 is disposed on the side of the light guide plate 130 and indirectly illuminated through the light guide plate 130.

The light guide plate 130 is a light switching element disposed in the inner space of the frame 110 and converting light from a plurality of point light sources incident from the LED light source 120 into a surface light source, It accomplishes. One side of the light guide plate 130 facing the LED light source forms the light incidence surface 130a and the back surface forms the light reflection surface 130b and the front surface forms the light emission surface 130c. The light guide plate 130 is made of transparent acrylic resin having a predetermined refractive index and may be made of resin such as polymethylmethacrylate (PMMA), poly styrene (PS), metastyrene (MS), or polycarbonate have.

The light guide plate 130 has a slit-shaped light extracting pattern 131 formed on the light output surface 130a of the front surface. The light extraction pattern 131 is formed in a direction parallel to the arrangement of the LED light sources 120 (or in a direction perpendicular to the traveling direction of light) as shown in FIG. 3, and the light output surface 130c has a predetermined fine width As shown in Fig. The light extracting patterns 131 are formed at a predetermined depth and are formed at a predetermined distance in the direction of the receiving light surface 130a '. The depth of each pattern increases as the distance from the LED light source 120 increases .

The light extracting pattern 131 has a predetermined inclination from the surface of the light guide plate 130 toward the center, and is inclined in a direction away from the LED light source 120. That is, the light extracting pattern 131 is formed into a slit-shaped linear slit.

The light extracting pattern 131 can easily control the illumination area according to the emission angle with respect to the area illumination device 100 used as the streetlight. The light extracting pattern 131 may be formed as a plurality of light sources for the surface illuminator 100 in which the LED 120b and the light guide plate 130 are combined, .

The reflective member 140 intervenes between the bottom surface of the frame 110 and the light guide plate 130. The reflective member 140 reflects light leaking from the back surface of the light guide plate to the front surface to improve the brightness of the surface lighting device. The reflective member 140 may be composed of a sheet or film having excellent light reflectance, and may be formed of a reflective layer in which a material in which the light reflecting agent is dispersed is coated directly on the inner surface of the frame.

Although not shown, a diffusion sheet for protecting the light guide plate and diffusing light emitted from the light guide plate 130 may be disposed on the front surface of the light guide plate 130.

The light emitted from the LED light source 120 is incident into the light guide plate 130 and emitted to the front surface while repeating total reflection within the light guide plate 130. [ At this time, the light emitted to the light output surface 130a of the light guide plate 130 has a specific configuration of the light extraction pattern 131, that is, the inclination angle? Of the pattern, the width w of the pattern, The optical characteristics such as the emission angle, uniformity, and the like of the emitted light are controlled.

4, the light extracting pattern 131 of the light guide plate 130 has an inclination angle θ of 20 ° to 70 ° with respect to the surface of the light exiting surface 130c and has a pattern width w of 0.01 mm to 1 mm. , And it is preferable to form a pattern interval p of 0.1 mm to 50 mm. When the inclination angle? Is less than 20 °, it is difficult to control the exit angle. When the inclination angle exceeds 70 °, the light is linearly shaped, which makes it difficult to control the uniformity. When the pattern width w is less than 0.001 mm, the amount of emitted light is insignificant and the effect of light extraction by the slit is hardly exhibited. When the pattern width w is larger than 1.0 mm, the light is diffused by the slit rather than uniformly. In addition, when the distance p between the patterns is less than 0.1 mm, it is disadvantageous to control the emission angle, and when the distance exceeds 50 mm, the uniformity is disadvantageous.

Generally, the street lamp is designed to illuminate the ground in an area in the range of approximately 10 [deg.] To 65 [deg.] With respect to the vertical direction according to the installation conditions. Therefore, the surface illumination device of the present invention can design the light extracting pattern to have the exit angle range.

Hereinafter, the optical characteristics of a surface illuminator according to various experimental examples of the present invention will be described.

[Experimental Example 1]

In Experimental Example 1, the optical characteristics of the light guide plate according to various changes of the inclination angle (?) Of the light extracting pattern 131 were experimented. Radiance Map and Intensity Map at the inclination angle (? And the optical characteristics of the emission angle with respect to the maximum luminance are shown in Table 1. At this time, the pattern width w was set to 0.1 mm, and the interval p between the patterns was set to 5 mm.

Inclination angle 45 ° 60 °
Radiance
Map

Intensity
Map

cd @ angle 259.66cd@37° 253.84cd@-27°

As can be seen from Table 1 above, a bright source appears at both 45 ° and 60 °, where the luminance is 259.66 cd and 253.84 at exit angles of 37 ° and -27 °, respectively cd indicates the maximum. The emission angle of the plane illumination device can be controlled in accordance with the inclination angle of the light extraction pattern 131. When the inclination angle of the light extraction pattern 131 is approximately 20 to 70 degrees, The emission angle control can be easily performed.

[Experimental Example 2]

In Experimental Example 2, the optical characteristics of the light guide plate according to various changes of the pattern width (w) of the light extracting pattern 131 were experimented. Radiance Map when the pattern width w was 0.05 mm and 0.5 mm, Table 2 shows the optical characteristics of the emission angle for the intensity map and the maximum luminance. At this time, the inclination angle? Of the pattern was 45 占 and the interval p between the patterns was 5 mm.

Pattern width 0.05mm 0.5mm Radiance
Map

Intensity
Map

cd @ angle 259.96cd@21° 278.27 cd@63°

As can be seen from the above Table 2, when the pattern width (w) is 0.05 mm and 0.5 mm, the light extracting effect of the light source is clearly shown, and the luminance is 21 ° and 63 ° And the maximum at 259.96 cd and 278.27 cd at the exit angle. Therefore, as the width (w) of the pattern increases, the luminance and emission angle characteristics also increase. Accordingly, the luminance (light extraction efficiency) and the emission angle of outgoing light can be controlled according to the pattern width w of the light extracting pattern 131, and the pattern width w of the light extracting pattern 131 is approximately 0.01 mm to 1.0 mm, the emission angle can be easily controlled while exhibiting high luminance.

[Experimental Example 3]

In Experimental Example 3, the optical characteristics of the light guide plate according to various changes in the pattern interval p of the light extracting pattern 131 were examined. Radiance Map and Intensity Map And the optical characteristics of the emission angle with respect to the maximum luminance are shown in Table 3. At this time, the inclination angle [theta] of the pattern was 45 [deg.] And the pattern width w was 0.1 mm.

Pattern spacing 3mm 7mm Radiance
Map

Intensity
Map

cd @ angle 249.78cd@23° 252.05cd@19°

As can be seen from the above Table 3, when the pattern interval (p) is 3 mm or 7 mm, the linear light source appears. However, the narrower the interval, the lower the sharpness and brightness of the linear light source. Accordingly, the brightness characteristic can be controlled according to the pattern interval p of the light extracting pattern 131. When the pattern interval p of the light extracting pattern 131 is approximately 0.1 mm to 50 mm, the brightness is high.

As described above, the planar illumination device according to the embodiment of the present invention can form a light extraction pattern having a linear slit shape oblique to the light output surface of the light guide plate, and can easily control the brightness and emission angle characteristics, A linear light source can be provided to decorate the appearance of the surface lighting apparatus.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the scope of the present invention.

100: Surface illuminator
110: frame 120: LED light source
130: light guide plate 131: light extracting pattern
140: reflective member

Claims (4)

A frame having a front opening and a receiving space formed therein;
A light source installed at one side of the receiving space of the frame and providing light to the receiving space;
A plate-shaped plate provided in the receiving space at a front surface of the light source and having a light incident surface on a side of the plate facing the light source, a reflection surface of the plate rear surface, and a light output surface on the front surface of the plate, A light guide plate in which a plurality of linear light exit patterns, which are cut in a slit shape in a direction perpendicular to a direction in which light is incident, are formed at predetermined intervals in a light incidence direction; And
And a reflective member interposed between a back surface of the light guide plate and a bottom surface of the frame. The light-emitting device according to claim 1,
Wherein the light source has an oblique shape in a direction away from the light incidence surface. The light-emitting device according to claim 2,
And the depth is changed so as to become deeper as the distance from the light incidence surface increases. The light-emitting device according to claim 3,
Wherein an angle? Of inclination with respect to the light-exiting surface is 20 to 70 and a width w of the pattern is 0.01 to 1 mm and an interval p between the patterns is 0.1 to 50 mm. Device.

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