Abstract:
An illumination lens including a first part being free of prismatic patterns, a second part including prismatic patterns on both sides of the first part and configured to increase light distribution in the both sides of the first part, and a lens cover covering the first and second parts with the first and second parts being disposed on a substantially same plane under the lens cover.

Description:
CROSS-REFERENCE TO A RELATED APPLICATION 
       [0001]    The present application claims priority under 35 U.S.C. 119 to Korean Patent Application No. 10-2009-0045342 filed on May 25, 2009, which is hereby incorporated by reference in its entirety. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present disclosure relates to an illumination lens and an illumination unit including the same. 
         [0004]    2. Discussion of the Related Art 
         [0005]    Most lighting in homes, offices, parks, etc. is provided via fluorescent and incandescent lamps. However, these types of light sources are not environmentally friendly, tend to have limited or short life spans and have high power consumption. Thus, the costs of operating and maintaining these related art types of lighting sources are significant, especially when considering many light sources are turned on at a single instance. 
       SUMMARY OF THE INVENTION 
       [0006]    Accordingly, one object of the present invention is to address the above-noted and other problems. 
         [0007]    Another object of the present invention is to provide a novel illumination lens and corresponding illumination unit having a high light and illuminance distribution. 
         [0008]    Yet another object of the present invention is to provide a novel illumination unit including an illumination lens disposed on a plurality of light emitting diodes that improves light and illuminance distribution. 
         [0009]    Still another object of the present invention is to provide a novel illumination unit that improves a blind spot generated due to a luminance difference. 
         [0010]    To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, the present invention provides in one aspect an illumination lens including a first part being free of prismatic patterns, a second part including prismatic patterns on both sides of the first part and configured to increase light distribution in the both sides of the first part, and a lens cover covering the first and second parts with the first and second parts being disposed on a substantially same plane under the lens cover. 
         [0011]    In another aspect, the present invention provides an illumination unit including an illumination lens including a first part being free of prismatic patterns, a second part including prismatic patterns on both sides of the first part and configured to increase light distribution in the both sides of the first part, and a lens cover covering the first and second parts with the first and second parts being disposed on a substantially same plane under the lens cover, and a light emitting module disposed under the illumination lens and including a plurality of light emitting diodes mounted on a board. 
         [0012]    Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings, which are given by illustration only, and thus are not limitative of the present invention, and wherein: 
           [0014]      FIG. 1  is a side sectional view of an illumination unit according to a first embodiment of the present invention; 
           [0015]      FIG. 2  is a side sectional view illustrating a light emitting module of  FIG. 1 ; 
           [0016]      FIG. 3  is a plan view illustrating the light emitting module of  FIG. 1 ; 
           [0017]      FIG. 4  is a plan view illustrating another example of the light emitting module of  FIG. 3 ; 
           [0018]      FIG. 5  is a side sectional view illustrating a gap member of  FIG. 1 ; 
           [0019]      FIG. 6  is a plan view illustrating the gap member of  FIG. 1 ; 
           [0020]      FIG. 7  is a rear view illustrating a lens of  FIG. 1 ; 
           [0021]      FIG. 8  is a side sectional view illustrating the lens of  FIG. 1 ; 
           [0022]      FIG. 9  is view illustrating light being emitted from the illumination unit of  FIG. 1 ; 
           [0023]      FIG. 10  is a view illustrating a light distribution of the illumination unit of  FIG. 1 ; 
           [0024]      FIG. 11  is a view illustrating an illuminance distribution of the illumination unit of  FIG. 1 ; 
           [0025]      FIG. 12  is a side sectional view of an illumination unit according to a second embodiment of the present invention; 
           [0026]      FIG. 13  is a side sectional view of an illumination unit according to a third embodiment of the present invention; 
           [0027]      FIG. 14  is a side sectional view of an illumination unit according to a fourth embodiment of the present invention; 
           [0028]      FIG. 15  is a side sectional view of an illumination unit according to a fifth embodiment of the present invention; and 
           [0029]      FIG. 16  is a side sectional view of an illumination unit according to a sixth embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0030]    Reference will now be made in detail to the embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. 
         [0031]      FIG. 1  is a side sectional view of an illumination unit  100  according to a first embodiment. As shown, the illumination unit  100  includes a light emitting module  101 , a gap member  130  and a lens  140 . The illumination unit  100  may be disposed in an outdoor lamp such as streetlights spaced a predetermined distance form each other. Further, the illumination unit  100  may illuminate light onto an area defined between the streetlights with adequate light and illuminance distribution. 
         [0032]    In addition, the light emitting module  101  includes a board  110  and a plurality of light emitting diodes  120  mounted on the board  110 . The light emitting diodes  120  are also mounted in various positions on the board  110 , which will be discussed in more detail later. Further, the board  110  can be an aluminum board, a ceramic board, a metal core printed circuit board (PCB), a general PCB, etc. 
         [0033]    The plurality of light emitting diodes  120  may also be a white light emitting diode (LED). Colored LEDs such as a red LED, a blue LED, and a green LED may also be selectively used as the light emitting diodes  120 . In addition, the light emitting diodes  120  preferably have an orientation angle of from about 120° to about 160° and a lambertian shape, but are not limited to this shape and orientation angle. 
         [0034]    Next, referring to  FIGS. 2 and 3 , the board  110  can have a circular Plate shape having a predetermined diameter D 1  that is receivable into the gap member  130 . A flat part  114  can also be disposed on an outer surface of a side of the board  110  to identify coupling positions between components of the illumination unit  100  or to prevent the components from being rotated. Also, a plurality of screw holes  113  can be defined in the board  110 , and be used for coupling the board  110  to a structure such as a streetlight. The board  110  can also be coupled through another fixing unit such as a rivet and a hook. Other coupling mechanisms can also be used 
         [0035]    Referring to  FIG. 3 , twelve light emitting diodes  120  are arrayed on the board  110 . For example, four light emitting diodes  120  are disposed on each of both sides about a center of the board  110  in a cross pattern shape, and four light emitting diodes  120  are disposed on four edges of the cross pattern shape, respectively. Thus, twelve light emitting diodes  120  are disposed on the board  100 . Referring to  FIG. 4 , eight light emitting diodes  120  are disposed in an array configuration. That is, the eight light emitting diodes  120  are disposed in a circular shape at positions spaced a predetermined distance from each other. 
         [0036]    Referring to  FIGS. 3 and 4 , the array configuration and the number of the light emitting diodes  120  disposed on the board  110  may be varied according to a light intensity, the light distribution, and the illuminance distribution. Further, the array configuration and the number of the light emitting diodes  120  may be changed within the technical scope of the embodiments. 
         [0037]    Next, and referring to  FIGS. 1 ,  5 , and  6 , the gap member  130  includes a sidewall part  131  having a circular shape and including a receiving portion  135 , an opening part  133  defined in an inner center region of the sidewall part  131 , and a reflective plate  132  disposed on an outer circumference of the opening  133 . The gap member  130  is also disposed outside the light emitting module  101  and allows the light emitting module  101  and the lens  140  to be spaced a predetermined distance G 1  from each other. The distance G 1  forms a space  105  between the lens  140  and the board  110  to induce an illumination angle and the light distribution. 
         [0038]    In addition, a silicon or silicon resin material may be filled into the space  105 , but other materials may also be used. The board  110  is also received into the receiving portion  135  defined below the inside of the sidewall part  131  of the gap member  130 . The light emitting diodes  120  are also exposed to the opening  133 . 
         [0039]    Further, an edge  143  of the lens  140  is disposed on an upper end of the sidewall  131  of the gap member  130 . The reflective plate  132  also extends inwardly from a circumference of an upper end of the gap member  130  with a predetermined inclined surface. That is, the reflective plate  132  can be inclined at a predetermined inclined angle θ 1  with respect to the outer circumference of the opening  133  of the gap member  130 . 
         [0040]    The inclined angle θ 1  may also be set so that the reflective plate  132  becomes thinner in thickness from the outside thereof toward the inside. The inclined angle θ 1  may also be changed according to a width of the reflective plate  132 . For example, the inclined angle θ 1  of the reflective plate  132  may range from about 0° to about 90° (0°&lt;θ 1 &lt;90°). Further, the reflective plate  132  corresponds to an outer bottom surface of the lens  140 . Thus, a reflected light amount can be changed according to the inclined angle θ 1  and the length of the reflective plate  132 . As shown in  FIGS. 5 and 6 , the inner opening  133  of the reflective plate  132  has a circular shape having a predetermined diameter D 3 . In addition, a flat part  134  of the gap member  130  is disposed at a position corresponding to the flat part  114  of the board  110  of  FIG. 3 . 
         [0041]    Referring to  FIGS. 1 ,  7 , and  8 , the lens is disposed on the light emitting module  101 . The cylindrical part  141  and prismatic parts  142  are also disposed on a light-incident side of the lens  140 , and the light emitting part  144  is disposed on a light-emitting side. Further, the edge  143  having a circular shape is disposed around the light-incident side of the lens  140 . 
         [0042]    In addition, a light-transmitting material may be injection-molded to form the lens  140 . The light-transmitting material may include a plastic material such as poly methyl methacrylate (PMMA) and polycarbonate (PC). Also, the cylindrical part  141  can be disposed in a direction of an axis Z perpendicular to an optical axis Y in a center region A 1  of the light-incident side. The cylindrical part  141  can also have a lens shape, a semicircular shape, or a polygonal shape in a cross-sectional shape thereof. A diameter D 4  of the cylindrical part  141  preferably has a width ranging from about ⅓ to about 1/10 with respect to a diameter D 5  of the light-incident side. 
         [0043]    The cylindrical part  141  of the lens  140  can also be disposed on the board  110 . Further, prismatic patterns are arrayed on both sides of the cylindrical part  141  to form the prismatic parts  142 . The prismatic patterns are disposed in the direction of the axis Z perpendicular to the optical axis Y, and apexes and valleys of the prismatic patterns are alternately arrayed in a direction of a horizontal axis (+X and −X). A distance between the patterns of the prismatic parts  142  can also be set to a preset distance, and the respective patterns may have a triangular shape in section. Both lateral surfaces S 1  and S 2  of the respective prismatic patterns can also have the same length and angle or have lengths and angles different from each other. Also, at least one of both lateral surfaces S 1  and S 2  can have a curved shape having a predetermined curvature, e.g., a convex curved shape. 
         [0044]    In addition, the prismatic patterns of the prismatic parts  142  can be spaced a predetermined distance or a random distance from each other. Further, the prismatic parts  142  can be axisymmetrically disposed about the cylindrical part  141 , and the respective prismatic patterns can be disposed at a constant distance. The prismatic parts  142  can also be disposed at both sides of the cylindrical part  141  and not be disposed under the edge  143 . In addition, because the prismatic parts  142  are disposed at both sides of the cylindrical part  141 , e.g., left and right sides of the cylindrical part  141 , the light distribution increases in left and right directions. 
         [0045]    Further, the lens  140  refracts and distributes light incident into the center region A 1  through the cylindrical part  141  of the light-incident side. The prismatic parts  142  also distribute light incident into both side regions A 2  and A 3  of the cylindrical part  141  in a horizontal direction. 
         [0046]    In addition, the light emitting part  144  can be an aspherical lens having a hemisphere shape. The light emitting part  144  also reflects or refracts incident light to emit the reflected or refracted light to the outside. Also, the light emitting part  144  can be a spherical Lens. The aspherical lens or the spherical lens may be selected in consideration of the desired light distribution and the illuminance distribution. 
         [0047]    Further, the light emitting part  144  refracts light incident through the cylindrical part  141  and the prismatic parts  142  to transmit or reflect the reflected light. Thus, the transmitted light can have a predetermined orientation distribution, and the reflected light can be converted into light having a light emitting angle via at least one of the prismatic parts  142 , the reflective plate  132 , and a top surface of the board  110 , thereby transmitting light through the light emitting part  144 . 
         [0048]    Next, referring to  FIG. 9 , light L 1 , L 2 , and L 3  emitted from the side light emitting diodes  120  of the light emitting module  110  are distributed in a horizontal direction through the prismatic parts  142  of the lens  140 . A portion L 3  of the distributed light L 1 , L 2 , and L 3  is reflected by the light emitting part  144  to change a critical angle of the light L 3  through the reflective plate  132  of the gap member  130  and the prismatic parts  142  of the lens  140 , thereby emitting the light L 3  through the light emitting part  144 . A portion L 4  of light emitted from the center-side light emitting diode  120  of the light emitting module  110  is also refracted and distributed through the cylindrical part  141  of the lens  140  to emit the refracted and distributed light to the outside through the light emitting part  144 . 
         [0049]    Next,  FIGS. 10 and 11  are views illustrating a light distribution and illuminance distribution of the illumination unit of  FIG. 1 , respectively. Referring to  FIGS. 10 and 11 , the light distribution B 1  in a front direction of the illumination unit  100  and the light distribution B 2  in a side direction of the illumination unit  100  are defined by the cylindrical part  141  and the prismatic parts  142  of the lens  140 . The light distribution B 1  and B 2  also improves the luminous intensities of a front lamp and side lamps. Thus, because the illumination distribution between the streetlights, for example, is improved, a blind spot can be reduced or removed. Also, a distance between the streetlights can be widened. 
         [0050]    Further, referring to  FIGS. 10 and 11 , the illuminance distribution of the illumination unit  100  has a rectangular shape according to a distance of the lens  140 . The illuminance distribution also has a rectangular shape due to the cylindrical part  141  of the lens  140  and the prismatic parts  142  disposed on both side of the cylindrical part  141 . That is, the illuminance distribution due to the prismatic parts  142  increases distribution in a horizontal direction that is an X-axis (−X-axis) direction. 
         [0051]    Next,  FIG. 12  is a side sectional view of an illumination unit  100 A according to a second embodiment of the present invention. Detailed descriptions of the same parts as those of the first embodiment are omitted. Referring to  FIG. 12 , the illumination unit  100 A includes the light emitting module  101 , the lens  140  and a gap member  151 . The gap member  151  may be formed in a dam shape using an epoxy or silicon resin material. The gap member  151  is also disposed on an outer circumference between the board  110  and the lens  140  to space the board  110  a predetermined distance from the lens  140 . 
         [0052]    Further, the light orientation distribution of the light emitting diodes  120  is improved by a space defined by the gap member  151 . In addition, the gap member  151  is disposed in a space between the board  110  and the lens  140 , and a phosphor may be added to the gap member  151  as necessary. The gap member  151  also couples the board  110  of the light emitting module  101  to the lens  140 . In addition, a reflective material for reflecting light traveling toward the board  110  may be coated on a top surface of the board  110  of the light emitting module  101 . Other materials can also be coated on the board  100  or no coating can be coated on the board  110 . 
         [0053]    Next,  FIG. 13  is a side sectional view of an illumination unit  100 B according to a third embodiment of the present invention. Detailed descriptions of the same parts as those of the first embodiment are omitted. Referring to  FIG. 13 , the illumination unit  100 B has a structure in which an edge  143 A disposed at an outer circumference of a lens  140  protrudes. The edge  143 A of the lens  140  can be disposed outside a top surface of the board  110  of the light emitting module  101  or be disposed on an outer surface of the board  110  of the light emitting module  101 . 
         [0054]    Further, the edge  143 A of the lens  140  can constantly maintain a distance G 1  between the board  110  of the light emitting module  101  and the lens  140 . In addition, a resin material such as silicon or epoxy may be filled into a space  105  between the light emitting module  101  and the lens  140 . A phosphor may also be added to the resin material. 
         [0055]    Because the board  110  is disposed under the edge  143 A of the lens  140 , the edge  143 A has a shape stepped with respect to an incident surface. In another example, a protrusion may be disposed around an outer circumference of the top surface of the board  110  to constantly maintain a distance between the board  110  and the lens  140 . 
         [0056]    Next,  FIG. 14  is a side sectional view of an illumination unit  100 C according to a fourth embodiment of the present invention. Detailed descriptions of the same parts as those of the first embodiment are omitted. Referring to  FIG. 14 , the illumination unit  100 C includes a reflective plate  155  disposed on the board  110  of the light emitting module  101 . The reflective plate  155  also has a diode hole  155 A and is disposed between light emitting diodes  120  of the board  110 . Thus, a portion of light emitted from the light emitting diodes  120  can be reflected by the reflective plate  155  to increase a reflected light amount. Therefore, the light efficiency is improved. 
         [0057]    In addition, a diffuser may be coated on a top surface of the reflective plate  155 , but is not limited thereto. Further, a gap member  153  is disposed under the edge  143  of the lens  140  to constantly maintain a distance G 1  between the lens  153  and the board  110 . Because the space  105  defined between the lens  153  and the board  110  is provided, the light emitted from the light emitting diodes  120  is dispersed within the space  105  between the board  110  and the lens  140 . The dispersed light is also dispersed through the prismatic part  142  and the cylindrical part  141  of the lens  140 . 
         [0058]    Next,  FIG. 15  is a side sectional view of an illumination unit  100 D according to a fifth embodiment of the present invention. Detailed descriptions of the same parts as those of the first embodiment are omitted. Referring to  FIG. 15 , the illumination unit  100 D has a structure in which a prismatic part  142 A of the lens  140  is modified. Prismatic patterns of the prismatic part  142 A are formed such that widths and periods of the prismatic patterns become gradually narrower from a central portion of the cylindrical part  141  toward the outside thereof. The prismatic patterns thus improve optical losses that gradually increase toward the outside of the lens  140 . Further, the prismatic patterns of the prismatic part  142 A can be gradually dense toward both side directions (−X-axis and +X-axis). The dense degree may be changed according to light distribution, but is not limited thereto. 
         [0059]    Next,  FIG. 16  is a side sectional view of an illumination unit  100 E according to a sixth embodiment of the present invention. Detailed descriptions of the same parts as those of the first embodiment are omitted. Referring to  FIG. 16 , the illumination unit  100 E has a structure in which a prismatic part  142 B of the lens  140  is modified. Prismatic patterns of the prismatic part  142 B are formed such that apexes or valleys of the prismatic patterns are gradually reduced in size or height from a central portion of a cylindrical part  141  toward the outside thereof. The prismatic patterns thus improve optical losses at the outside of the lens  140  and light extraction efficiency. In addition, the prismatic patterns of the prismatic part  142  can extend up to a bottom surface of an edge  143 , but is not limited thereto. The prismatic patterns of the prismatic part  142 B can also be gradually dense toward both side directions (−X-axis and +X-axis). The dense degree may be changed according to light distribution, but is not limited thereto. 
         [0060]    Embodiments of the present invention improve light distribution and illuminance distribution of outdoor lamps such as streetlights and provide the illumination unit having high illuminance distribution in consideration of a distance between the streetlights. Embodiments of the present invention also provide the illumination unit having a desired illuminance distribution without using a separate structure. 
         [0061]    Further, embodiments of the present invention improve the light and illuminance distribution of the outdoor lamps such as the streetlights, outdoor lights, etc. Also, embodiments of the present invention provide the illumination unit having the illuminance distribution in consideration of the distance between the streetlights. Embodiments of the present invention further provide the illumination unit having the desired illuminance distribution without using the separate structure. In addition, because the embodiments of the present invention form a desired light distribution using the LED array and the lens which are flush with each other, lights having uncomplicated configurations are provided. 
         [0062]    Further, the light emitting diodes (LEDs) have advantages such as low power consumption, long lifetime, and environment friendly properties. Thus, the arrayed LEDs and corresponding lens of the present invention provide advantages over traditional lighting. 
         [0063]    Any reference in this specification to “one embodiment,” “an embodiment,” “example embodiment,” etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the purview of one skilled in the art to effect such feature, structure, or characteristic in connection with other ones of the embodiments. 
         [0064]    Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.