Patent Description:
In general, various types of lighting devices may be installed in a road or a tunnel. As a conventional lighting device, a sodium lamp, a halogen lamp, a mercury lamp or a metal halide lamp have been used. However, these lamps consume a lot of electricity, have a short usage life, have a high maintenance cost, and have an environmental pollution problem.

Accordingly, efforts to apply a light emitting diode (LED) light source have been continued to solve the problem of power consumption according to the use of the lamp described above and to extend the lamp replacement cycle according to the extension of the lamp life.

The lighting device using the LED as a light source disposes a light distribution lens at a position corresponding to a light source unit, and uses by diffusing or collecting the light of the LED light source as necessary. As described above, if the light source is composed of a plurality of LED elements, a plurality of light distribution lenses may be arranged at positions corresponding to the respective LED elements. At this time, the plurality of light distribution lenses may be equally configured to have any one shape of oval or circular. For example, if the light distribution lens is applied to the oval lenses as illustrated in <FIG>, the light distribution area projected by the oval lens is oval shape and its projection distance is short. Alternatively, if the light distribution lens is applied to the circular lenses as illustrated in <FIG>, the light distribution area projected by the circular lens is formed in a circular shape, and its projection distance is formed longer than that of the oval light distribution lens. However, there is a problem in that the circular light distribution lens has a large brightness difference between the center and the periphery of the light distribution area.

As described above, if only any one of the oval lens and the circular lens is used as the light distribution lens in the LED lighting device, the light distribution areas of adjacent lighting devices may overlap each other to increase the brightness, but dark portions (I, II) may be formed or distribution of lighting intensity may also be uneven. The formation of such a dark portion or non-uniformity of the lighting intensity may cause the driver to be optical illusion and fatigue, which may act as a serious factor that may cause a traffic accident.

Further, a road lighting device such as a general street lamp is installed at a height of about <NUM> or more, there is a hassle to necessarily use a separate maintenance vehicle at the time of maintenance work of the lighting device.

Document <CIT> relates to an illumination device with multiple illumination distribution patterns utilizing multiple optical modules.

Document <CIT> discloses an optical element, a light source, and an assembly method thereof, and more particularly to a light action element module, a lighting device, and a lighting system.

Document <CIT> relates to an LED lighting fixture for outdoor use that uses LED light sources.

Document <CIT> describes a lighting device for a crosswalk, wherein the beam irradiation angle for a LED lamp lens is disposed in a plurality of rows above and below the lighting lamp.

Document <CIT> relates to a luminaire comprising a set of light sources and a set of optical elements, wherein, the light sources consist of light-emitting diodes (LEDs).

An object of the present disclosure is to provide a lens cover and an LED lighting device having the same, which may minimize occurrence of a dark portion even while extending the light distribution area of an LED light source.

Further, another object of the present disclosure is to provide a lens cover and an LED lighting device having the same, which may sufficiently comply with the recommendations of the Road Traffic Act, such as an average brightness, an uniformity ratio of illumination, and an unified glare rating even if the installation height of the lighting device is implemented to a low height of less than <NUM>.

For achieving the objects, a lens cover according to an embodiment of the present disclosure is the lens cover having a plurality of light distribution lenses arranged at positions corresponding to a plurality of LED light sources, and the plurality of light distribution lenses include a first light distribution lens and a second light distribution lens having different shapes from each other, and the first light distribution lens and the second light distribution lens are mixedly arranged at positions corresponding to the plurality of LED light sources.

For achieving the objects, an LED lighting device according to the invention includes a post, a head connected to one end of the post, and a lens cover coupled to the head, and the lens cover has a plurality of light distribution lenses arranged at positions corresponding to a plurality of LED light sources, the plurality of light distribution lenses include a first light distribution lens and a second light distribution lens having different shapes from each other, and the first light distribution lens and the second light distribution lens are mixedly arranged at positions corresponding to the plurality of LED light sources.

According to an embodiment of the present disclosure, it is possible to provide the lighting device, which satisfies the recommendations of the Road Traffic Act, such as an average brightness, a uniformity ratio of illumination, and a unified glare rating even if the lighting device of a relatively low height is installed on the roadside.

Hereinafter, the present disclosure will be described with reference to the accompanying drawings. However, the present disclosure may be implemented in various forms, and accordingly, is not limited to the embodiment described herein. Further, a portion irrelevant to the description has been omitted in the drawings for clearly describing the present disclosure, and like portions has been denoted by like reference numerals throughout the specification.

Referring to <FIG>, an LED street lamp <NUM> according to an embodiment of the present disclosure includes a post <NUM>, a head <NUM>, and a cover <NUM>.

The post <NUM> is fixedly installed on the installation surface (ground) of the roadside along the longitudinal direction of the road, and has a predetermined height. In an embodiment, the post <NUM> may be formed at a low height of <NUM> or less. For example, if an LED lighting device according to an embodiment is installed adjacent to a bridge, the length of the post <NUM> may be formed to be <NUM> or less, thereby minimizing interference with the bridge work of the maintenance vehicle. Further, it is possible to reduce the length of the post compared to the conventional, thereby reducing the manufacturing cost of each lighting device.

The head <NUM> is connected to the upper portion of the post <NUM> to have a predetermined inclination in one side direction. The head <NUM> may be provided with a heat dissipation member (not illustrated) so that at least one LED (see <FIG>) is operated within a range of a proper temperature.

The cover <NUM> is coupled to one side of the head <NUM>, and the cover <NUM> may secure a light distribution area of a setting range. A printed circuit board on which a plurality of LEDs are mounted is accommodated inside the cover <NUM>, that is, between the cover <NUM> and the head <NUM>. Assuming a two-lane road, the cover <NUM> may be formed at an angle (α) of <NUM>° or more and <NUM>° or less with respect to the axis extending from the post <NUM>.

Referring to <FIG>, the LED lighting device <NUM> according to an embodiment includes an LED module <NUM> and the cover <NUM>.

The LED module <NUM> is coupled so that light is distributed to one side of the head <NUM>, for example, the roadside. The LED module <NUM> is manufactured in the form of a module in which a plurality of LEDs <NUM> are mounted on a printed circuit board <NUM>. The number of the LEDs <NUM> used in the LED module <NUM> may be determined according to the length, the intensity of illumination, or the like of the set post <NUM>.

The cover <NUM> has a lens matrix composed of a plurality of lenses. In other words, the cover <NUM> includes a first light distribution lens <NUM> and a second light distribution lens <NUM> having different shapes from each other, and the first light distribution lens <NUM> and the second light distribution lens <NUM> are mixedly arranged with each other.

The first light distribution lens <NUM> irradiates light at a relatively short distance from the lighting device with respect to the lighting device, and the second light distribution lens <NUM> irradiates light at a farther distance than the first light distribution lens <NUM>. The first light distribution lens <NUM> is formed to have an oval hemispherical shape (hemispherical shape with different diameters of X and Y axes from each other when viewed in plane), and the second light distribution lens <NUM> is formed to have a hemispherical shape.

At this time, at least one uneven portion 142a is provided on the surface of the second light distribution lens <NUM>. The uneven portion 142a is formed in the same direction as the axial direction of the post <NUM>. The uneven portion 142a increases the surface area of the second light distribution lens <NUM> and induces scattered reflection of light generated from the LED <NUM>, thereby increasing the light distribution area of the light projected from the second light distribution lens <NUM>. Accordingly, the light distribution range of the light may be more extended along the longitudinal direction of the road.

Referring to <FIG>, the cover <NUM> of an embodiment has a lens matrix arranged in two rows, a plurality of first light distribution lenses <NUM> are arranged in a first row, and a plurality of second light distribution lenses <NUM> are arranged in a second row. However, the lens matrix is not necessarily limited thereto. For example, as in <FIG>, the first light distribution lenses <NUM> may be arranged at the outermost of both sides of the first row and the second row of the cover <NUM> and the second light distribution lenses <NUM> may be arranged between the first light distribution lenses, or as in <FIG>, the second light distribution lenses <NUM> may be arranged at the outermost of both sides of the first row and the second row of the cover <NUM> and the first light distribution lenses <NUM> may also be arranged between the second light distribution lenses. Further, in an embodiment, the lens is arranged to have a matrix of <NUM>*<NUM>, but the matrix of the lens may be increased or decreased as necessary.

Meanwhile, a plurality of fastening holes <NUM> are formed at the periphery of the cover <NUM> for fastening with the head <NUM>, and the cover <NUM> may be coupled to the head <NUM> by using a fixing member such as a screw penetrating the fastening hole <NUM>.

<FIG> and <FIG> illustrate a light distribution diagram after light has been projected on the lane in a state where an LED lighting device according to an embodiment of the present disclosure has been installed on the roadside. At this time, the height of the lighting device was <NUM>, the installation distance between the lighting devices was <NUM>, the width of the road was <NUM> (based on two lanes), the inclination angle of the cover was <NUM> degrees, the ambient temperature was <NUM>, and the illuminance of the LED was 6000lm.

Accordingly, the light distribution area projected from the lighting device is formed so that a plurality of substantially oval short-distance light distribution areas are overlapped with each other on the lane of a position close to the lighting device by the first light distribution lenses <NUM>, and a plurality of substantially circular long-distance light distribution areas are overlapped with each other on the lane of a position farther than the above by the second light distribution lenses <NUM>. Further, the short-distance light distribution area by the first light distribution lenses <NUM> and the long-distance light distribution area by the second light distribution lenses <NUM> are also overlapped with each other.

Accordingly, it is possible to implement the uniform brightness distribution in both short and long distances with respect to the lighting device, and to minimize occurrence of the dark portion on the lane.

Meanwhile, Table <NUM> below represents the results if the LED lighting device was installed according to the installation environment as described above.

According to the Road Traffic Act, it is recommended that uniformity ratio of illumination of an artificial lighting is <NUM>/<NUM> and the unified glare rating is within <NUM>%. Here, the brightness represents the amount of light reflected from the target surface, and the uniformity ratio of illumination, as the degree of uniformity of illumination of the illuminance intensity distribution, represents a ratio of a high illuminance portion and a low illuminance portion. Accordingly, it may be seen that even if the lighting device of a relatively low height of <NUM> is applied as in an embodiment, the average brightness, the uniformity ratio of illumination, and the unified glare rating all satisfy the recommendations.

Claim 1:
An LED lighting device (<NUM>), comprising:
a post (<NUM>);
a head (<NUM>) connected to one end of the post (<NUM>); and
a lens cover (<NUM>) coupled to the head (<NUM>),
wherein the lens cover (<NUM>) is arranged at an angle of <NUM>° or more and <NUM>° or less with respect to the axis extending from the post (<NUM>) of the lighting device (<NUM>)
wherein the lens cover (<NUM>) has a plurality of light distribution lenses arranged at positions corresponding to a plurality of LED light sources,
wherein the plurality of light distribution lenses comprise a first light distribution lens (<NUM>) and a second light distribution lens (<NUM>) having different shapes from each other, and
wherein the first light distribution lens (<NUM>) and the second light distribution lens (<NUM>) are mixedly arranged at positions corresponding to the plurality of LED light sources,
wherein the first light distribution lens (<NUM>) is an oval hemispherical shape, and the second light distribution lens (<NUM>) is a hemispherical shape.
wherein one or more uneven portions (142a) are formed on the surface of the second light distribution lens (<NUM>), and wherein the one or more uneven portions (142a) are formed in the same direction as an axial direction of the post (<NUM>) to which the head (<NUM>) is connected,
wherein the first light distribution lens (<NUM>) forms short-distance light distribution area on a road,
wherein the second light distribution lens (<NUM>) forms long-distance light distribution area formed further away from the post (<NUM>) than the short-distance light distribution area on the road.