Patent Publication Number: US-2015062872-A1

Title: Lens module, light source assembly and backlight assembly having the lens module

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority, under 35 U.S.C. 119, from Korean Patent Application No. 10-2013-0104825 filed on Sep. 2, 2013 in the Korean Intellectual Property Office, the content of which is herein incorporated by reference in its entirety. 
     TECHNICAL FIELD 
     The inventive concept disclosed herein relates to a lens module, a light source assembly, and a backlight assembly having the lens module. 
     BACKGROUND 
     In general, a liquid crystal display has advantages such as thinness, light weight, and low power consumption compared to other types of displays in the market. As a result, liquid crystal displays are used in various applications such as monitors, notebooks, cellular phones, large televisions, and the like. A liquid crystal display includes a liquid crystal display panel displaying an image by using light transmittance of a liquid crystal, and a backlight assembly placed below the liquid crystal display panel and providing light to the liquid crystal display panel. 
     The backlight assembly includes light sources generating light required to display the image on the liquid crystal display panel. For example, the light sources may be a cold cathode fluorescent lamp (CCFL), an external electrode fluorescent lamp (EEFL), a flat fluorescent lamp (FFL), or a light emitting diode (LED). 
     In recent years, an LED is often used as the light source because it has low power consumption and is environmentally friendly. An LED module may include a red LED chip, a green LED chip, and a blue LED chip. The LED module may output white light by mixing the light emanating from a plurality of LED chips. 
     The LED chips have a light distribution of a point light source type, and the point light source type light distribution is changed to a plane light source type light distribution to be emitted to a predetermined region by a dedicated lens. 
     SUMMARY 
     The inventive concept presented herein provides a lens module, a light source assembly, and a backlight assembly that can achieve light distribution with improved uniformity. 
     In another aspect, the inventive concept presented herein provides a lens module, a light source assembly, and a backlight assembly capable of minimizing a color spread phenomenon by improving light mixture. 
     According to embodiments of the inventive concept, at least the following effects are obtained. 
     A lens module capable of improving light luminance uniformity and color uniformity can be provided. 
     A light source assembly and a backlight assembly that have the improved light luminance uniformity and color uniformity are provided. 
     The effects of the embodiments are not limited to the aforementioned effects, and other effects that are not explicitly mentioned above will be apparently understood by the person skilled in the art from the recitations of the claims. 
     According to an aspect of the inventive concept, there is provided a light source assembly that includes: a light source module capable of emitting light; and a lens module positioned on the light source module, wherein the lens module includes a light collecting lens configured to collect the light emitted from the light source module; and a diffusion lens positioned on the light collecting lens, and including an inner curved surface on which light from the light collecting lens is incident and an outer curved surface through which the light incident on the inner curved surface exits the diffusion lens, and wherein the light emitted from the light source module forms a light collecting region on the inner curved surface by passing through the light collecting lens. 
     According to another aspect of the inventive concept, there is provided a lens module collecting and diffusing light emitted from a light source module. The lens module includes: a light collecting lens collecting the light emitted from the light source module; and a diffusion lens positioned on the light collecting lens, and including an inner curved surface that is configured to receive from light the light collecting lens and an outer curved surface through which the light exits the diffusion lens, wherein there is a light collecting region on the inner curved surface where light from the light collecting lens is concentrated. 
     According to yet another aspect of the inventive concept, there is provided a backlight assembly. The backlight assembly includes: a circuit substrate; at least one light source assembly positioned on the circuit substrate; and a receiving member receiving the circuit substrate, wherein the light source assembly includes: a light source module capable of emitting light; and a lens module positioned on the light source module, the lens module including: a light collecting lens collecting the light emitted from the light source module; and a diffusion lens positioned on the light collecting lens, and including an inner curved surface in which light exiting the light collecting lens is incident and an outer curved surface where the light incident on the inner curved surface exits the diffusion lens, and the light emitted from the light source module forms a light collecting region on the inner curved surface by passing through the light collecting lens. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other features and advantages of the inventive concept will become more apparent by describing in detail embodiments thereof with reference to the attached drawings, in which: 
         FIG. 1  is an exploded perspective view of a backlight assembly according to an embodiment; 
         FIGS. 2 and 3  are cross-sectional views of a light source assembly taken along line P 1 -P 2  of  FIG. 1 ; 
         FIG. 4  is a perspective view illustrating a diffusion lens in a lens module illustrated in  FIG. 3 ; 
         FIG. 5  is a plan view of the diffusion lens illustrated in  FIG. 4 ; 
         FIG. 6  is a cross-sectional view of the diffusion lens taken along line I 1 -I 2  of  FIG. 5 ; 
         FIG. 7  is a cross-sectional view of the diffusion lens taken along line I 3 -I 4  of  FIG. 5 ; 
         FIG. 8  is a cross-sectional view illustrating a modified embodiment of the diffusion lens illustrated in  FIG. 7 ; 
         FIG. 9  is a cross-sectional view illustrating another modified embodiment of the diffusion lens illustrated in  FIG. 7 ; 
         FIG. 10  is a cross-sectional view illustrating a light collecting lens according to an embodiment; 
         FIG. 11  is a plan view of the light collecting lens illustrated in  FIG. 10 ; 
         FIG. 12  is a cross-sectional view illustrating a modified embodiment of the light collecting lens illustrated in  FIG. 10 ; 
         FIG. 13  is a cross-sectional view illustrating another modified embodiment of the light collecting lens illustrated in  FIG. 10 ; 
         FIG. 14  is a cross-sectional view illustrating a light source module according to an embodiment; 
         FIG. 15  is a cross-sectional view illustrating a modified embodiment of the light source module illustrated in  FIG. 14 ; and 
         FIG. 16  is a cross-sectional view illustrating another modified embodiment of the light source module illustrated in  FIG. 14 . 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Advantages and features of the present invention and methods of accomplishing the same may be understood more readily by reference to the following detailed description of embodiments and the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the concept of the invention to those skilled in the art, and the present invention will only be defined by the appended claims. Like reference numerals refer to like elements throughout the specification. 
     The terminology used herein is for the purpose of describing the particular embodiments that are disclosed and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     It will be understood that when an element or layer is referred to as being “on”, “connected to” or “coupled to” another element or layer, it can be directly on, connected or coupled to the other element or layer or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly connected to,” or “directly coupled to” another element or layer, there are no intervening elements or layers present. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
     It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the inventive concept. 
     Spatially relative terms, such as “beneath”, “below”, “lower”, “above”, “upper”, and the like, may be used herein for ease of description to describe one element or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the exemplary term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. 
     Embodiments are described herein with reference to cross-section illustrations that are schematic illustrations of idealized embodiments (and intermediate structures). As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, these embodiments should not be construed as limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, an implanted region illustrated as a rectangle will, typically, have rounded or curved features and/or a gradient of implant concentration at its edges rather than a binary change from implanted to non-implanted region. Likewise, a buried region formed by implantation may result in some implantation in the region between the buried region and the surface through which the implantation takes place. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the actual shape of a region of a device and are not intended to limit the scope of the present invention. 
     Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and this specification and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
     Hereinafter, embodiments of the inventive concept will be described with reference to the drawings. 
       FIG. 1  is an exploded perspective view of a backlight assembly according to an embodiment. 
     Referring to  FIG. 1 , a backlight assembly  10  according to an embodiment may include a circuit substrate  210 , a plurality of light source assemblies  100 , and a receiving container  220 . 
     The circuit substrate  210  is a thin substrate on which wires (not shown) are formed. The circuit substrate  210  may include, for example, a printed circuit board (PCB) or a metal coating printed circuit board (MCPCB) in which a printed circuit board is coated with metal having high thermal conductivity. Further, the circuit substrate  210  may include a flexible printed circuit board (FPCB) having flexibility as necessary. Power applied from the outside in order to drive a light source in the light source assembly  100  may be transmitted to the light source assemblies  100  through the wires. 
     The light source assemblies  100  are placed on the circuit substrate  210  to generate light. The light source assemblies  100  may be fixed onto the circuit substrate  210  by combining terminals (not shown) and the circuit substrate  210 . The light source assemblies  100  will be described below in detail. 
     The receiving container  220  may include a bottom part  221  and a side wall  223  extending from an edge of the bottom part  221  and forming a receiving space in order to receive the circuit substrate  210  joined with the light source assembly  100 . The circuit substrate  210  may be placed on the bottom part  221  of the receiving container  220 . The receiving container  220 , in one embodiment, may be made of metal that has high rigidity and low deformability, but is not limited thereto and may be made of plastic, or the like. 
     The backlight assembly  10  may further include a light guiding member  230  that is placed above the light source assemblies  100 . The light guiding member  230  may be spaced apart from the light source assemblies  100  by a predetermined gap. The light guiding member  430  may be made of poly methyl methacrylate (PMMA), as one example, but is not limited thereto. The backlight assembly  10  may include the light guiding member  230  as necessary and the light guiding member  230  may be omitted. 
     The backlight assembly  10  may further include a diffusion plate  240  placed above the light guiding member  230 . The diffusion plate  240  may be spaced apart from the light guiding member  230  by a predetermined minimum gap. The diffusion plate  240  diffuses light emitted from the light guiding member  230  to improve luminance uniformity of light. The diffusion plate  240  has a plate shape having a predetermined thickness. The diffusion plate  240  may be made of, for example, poly methyl methacrylate (PMMA) and may include a diffusion agent for diffusing light inside. Further, although not illustrated in the figure, the diffusion plate  240  may further include a plurality of diffusion patterns formed on at least one surface to more uniformly diffuse the supplied light. 
     The backlight assembly  10  may further include an optical sheet  250  having various functions depending on a required luminance characteristic. For example, the optical sheet  250  may be a prism sheet and collect light emitted from the diffusion plate  240 . The prism sheet may include vertical and horizontal prism sheets that collect light in vertical and horizontal direction, respectively, but the inventive concept is not limited thereto. 
     The aforementioned backlight assembly  10  supplies light to a display panel  300 , and as a result, the display panel  300  may display an image provided to the outside. The display panel  300  may include a first substrate  310  and a second substrate  330  that are bonded to each other, and a liquid crystal layer (not illustrated) interposed between two substrates. Herein, although not illustrated in the figure, in general, a plurality of gate lines and data lines cross each other, and as a result, a pixel is defined on an inner surface of the first substrate  310  (herein referred to as a “lower substrate”), a thin-film transistor substrate, or an array substrate, a thin film transistor (TFT) may be provided for each cross point, and connected with a transparent pixel electrode formed in each pixel to correspond to each other one to one. For example, color filters of red (R), green (G), and blue (B) colors corresponding to each pixel, and a gate line and a data line positioned among the color filters, and a black matrix positioned among the color filters and covering the gate line and the data line, and the thin film transistor or the like may be provided on an inner surface of the second substrate  300  called an upper substrate or a color filter substrate. Further, a transparent common electrode covering the color filters of the red (R), green (G), and blue (B) colors, and the black matrix may be provided on the second substrate  330 . 
       FIGS. 2 and 3  are cross-sectional views of a light source assembly according to an embodiment and in more detail, are cross-sectional views of the light source assembly taken along line P 1 -P 2  of  FIG. 1 . 
     Referring to  FIGS. 2 and 3 , the light source assembly  100  according to the embodiment of the present invention may include a light source module  110  and a lens module LM. 
     The light source module  110  may include point light sources generating different single-color lights that may be combined to generate white light, and the LED may be used as a point light source. For example, the point light sources may include a red LED generating red light, a blue LED generating blue light, and a green LED generating green light, and the red light, the blue light, and the green light are mixed with each other to generate white light. Alternatively, the light source module  110  may include a white LED generating white light. 
     Alternatively, the light source module  110  may include a resin including the green LED, the blue LED, and a red fluorescent substance. In this case, the light source module  110  may output the white light by using the light provided from the plurality of LEDs, and the red fluorescent substance absorbs blue light to display a red color. The light source module  110  including the fluorescent substance will be described below in detail with reference to  FIGS. 14 to 16 . 
     The lens module LM may be placed on the light source module  110  and include a light collecting lens  130  and a diffusion lens  150 . 
     The light collecting lens  130 , which is an optical member that collects light emitted from the light source module  110 , may include a first lens surface  130   a  positioned between the light source module  110  and a second lens surface  130   b . In addition, the light emitted from the light source module  110  is refracted on the first lens surface  130   a  and refracted on the second lens surface  130   b  once more when passing through an inner part of the light collecting lens  130 . The light exiting the light collecting lens  130  is collected to be provided to the diffusion lens  150 . 
     The diffusion lens  150  as an optical member that diffuses light collected by transmitting the light collecting lens  130  to emit the diffused light to the outside may have an inner curved surface  151  in which the light collected by the light collecting lens  130  is incident and an outer curved surface  157  contacting the outside. The light collected by the light collecting lens  130  is once refracted on the inner curved surface  151  through an air layer and refracted on the outer curved surface  157  once more through an inner part of the diffusion lens  150  to be diffused and emitted to the outside. 
     That is, the light emitted from the light source module  110  is collected through the light collecting lens  130  and the light collected through the light collecting lens  130  is diffused to the outside through the diffusion lens  150 . Herein, the light collected through the light collecting lens  130  forms a light collecting region on the inner curved surface  151  of the diffusion lens  150 . 
     The light collecting region refers to a part of the inner curved surface  151  in which the light collected through the light collecting lens  130  is concentrated. The light collecting region may be a point or have the same shape as a part of the inner curved surface  151 . In other words, the light collecting region as a part of the inner curved surface  151  may be defined as where the light collected through the light collecting lens  130  is incident. Further, when the light collecting region is a point, the light collecting region may be defined as a focal point of the light collecting lens  130  and in this case, the focal point of the light collecting lens  130  would be positioned on the inner curved surface  151 . 
     The light source assembly  100  according to one embodiment has the advantage of light being collected through the light collecting lens  130  of the lens module LM and thereafter, being diffused through the diffusion lens  150  to improve overall uniformity of light supplied to the outside. In particular, when the light source module  110  includes point light sources generating different single-colored light beams, the light source module  110  has advantages of improved color mixing level of light provided to the outside and reduced color shading. This benefit stems from the different single-color light beams being collected through the light collecting lens  130  and then being diffused through the diffusion lens  150 . 
     In one embodiment, the light source assembly  100  is applied to the backlight assembly  10  of  FIG. 1 , but this is just one example. In some embodiments, the light source assembly  100  of this disclosure may be applied to even a general illumination device field in addition to the backlight assembly  10  of  FIG. 1 . 
       FIGS. 4 and 5  are a perspective view and a plan view illustrating a diffusion lens in the lens module illustrated in  FIG. 3 .  FIG. 6  is a cross-sectional view of the diffusion lens taken along line I 1 -I 2  of  FIG. 5 .  FIG. 7  is a cross-sectional view of the diffusion lens taken along line I 3 -I 4  of  FIG. 5 . 
     Referring to  FIGS. 4 to 6 , the diffusion lens  150  of the present invention may include a plurality of supports  152  formed on the bottom thereof. The supports  152  are seated on the circuit substrate  210  of  FIGS. 1 to 3  to assist the lens module LM of  FIG. 3  to be seated at an accurate location. The supports  152  may extend from the bottom of the diffusion lens  150  as illustrated in the figure and at least three supports  152  are formed to assist the lens module LM to be seated at the accurate location. When a separate groove is formed on the circuit substrate  210  of  FIGS. 1 to 3 , the supports  152  may be joined to the grooves of the circuit substrate  210  of  FIGS. 1 to 3 . 
     The supports  152  may be formed integrally with the diffusion lens  150  or formed as separate components to be joined with the diffusion lens  150 . 
     However, the above embodiments are just examples, and the shape and number of the supports  152  may be appropriately changed as necessary. 
     Referring to  FIG. 7 , the diffusion lens  150  may have an inner curved surface  151  and an outer curved surface  157  having an oval surface shape in order to more widely diffuse the light generated from the point light source. In general, an oval is defined as a locus of points in which a sum of distances from two apexes is constant and in this case, each of the two apexes are called a focus. Further, in the oval, an axis linking two apexes by a straight line is a long axis and an axis that is perpendicular to the long axis while passing through the center of the oval is a short axis. 
     Therefore, in an oval, the length of the long axis is larger than the length of the short axis. Meanwhile, an oval surface is formed while rotating the long axis or the short axis of the oval as a rotational axis. 
     The inner curved surface  151  and the outer curved surface  157  of the diffusion lens  150  according to the present invention may have an oval surface shape in which the long axes are formed to be perpendicular to each other. For example, when the long axis of the inner curved surface  151  is formed in a vertical plane direction, the long axis of the outer curved surface  157  may be formed in a horizontal direction. As such, when the long axes of the inner curved surface  151  and the outer curved surface  157  are formed to be perpendicular to each other, the thickness of the diffusion lens  150 , that is, a distance between the inner curved surface  151  and the outer curved surface  157  is changed depending on the location. Therefore, a path of the light passing through the diffusion lens  150  differs according to the exact location on the lens, due to a difference in thickness of the diffusion lens  150 . As a result, the emitted light is further diffused to be emitted. 
     In one embodiment, the inner curved surface  151  has the shape of a first oval surface  112  in which a long axis A1 is formed in the first vertical plane direction and the outer curved surface  157  may have a shape of a second oval surface  122  in which a long axis A2 is formed in the horizontal plane direction. 
     A light scattering pattern  155  may be formed on the inner curved surface  151  and the light scattering pattern  155  may have predetermined roughness. The light scattering pattern  155  may be formed throughout the inner curved surface  151  and formed at only a portion corresponding to the aforementioned light collecting region in the description of  FIG. 3  in the inner curved surface  151 . 
     The light scattering pattern  155  is formed through surface processing of the inner curved surface  151  to be formed integrally with the diffusion lens  150  as illustrated in  FIG. 6 . The light scattering pattern  155  may be formed in an engraving pattern as illustrated in  FIG. 7 , but is not limited thereto and a part or all of the light scattering patterns may be configured by an embossing pattern. Alternatively, a pattern is formed in a separate member (for example, an optical film), or the like and the pattern is attached onto the inner curved surface  151  to form the light scattering pattern  155 . 
     As the light scattering pattern  155  is formed on the inner curved surface  151 , the light collected by the light collecting lens  130  of  FIG. 3  is scattered by the light scattering pattern  155  and then diffused to exit the diffusion lens  150 . As a result, the uniformity of the light provided to the outside may be further improved. Further, when light which is fully reflected on the outer curved surface  157  through the inner part of the diffusion lens  150  is again reflected through the inner curved surface  151 , the corresponding reflected light may be scattered through the light scattering pattern  155  again, and as a result, more uniform light may be provided to the outside. Moreover, when the light source module  110  of  FIG. 3  emits two or more different single light beams, the color mixing level and the color uniformity may be further improved. In particular, when the light collecting region has the shape of the point, in other words, when the focus of the light collecting lens  130  is positioned on the inner curved surface  151 , the aforementioned light uniformity improvement effect and color uniformity improvement effect may be maximized. 
     The aforementioned diffusion lens  150  according to the present invention may be made of optical glass or an optical synthetic resin. In this case, as the optical glass, BK7 or SK5 may be used and as the optical synthetic resin, poly methyl methacrylate (PMMA) or polycarbonate (PC) may be used, but the present invention is not limited thereto. As shown in  FIG. 7 , there is a space between the light collecting lens  130  and the inner curved surface  151  of the diffusion lens  150 . This space may be filled with air. 
     A lens joining groove  153  may be formed in the inner part of the diffusion lens  150 . In particular, the lens joining groove  153  may be formed where both ends of the inner curved surface  151  are positioned. The lens joining groove  153  to which the light collecting lens  130  is joined may have a shape corresponding to the shape of the light collecting lens  130 . That is, the light collecting lens  130  may be inserted into and joined to the lens joining groove  153  of the diffusion lens  150  such that the diffusion lens  150  and the light collecting lens  130  may form a lens assembly (herein also referred to as the lens module LM). Therefore, a process of manufacturing the light source module  110 , a process of seating the light source module  110  on the circuit substrate  210 , and a process of manufacturing the lens module LM are performed independently of each other, improving manufacturing process efficiency. Moreover, as a separate component for supporting the light collecting lens  130  is not required in the above configurations, the overall structure of the light source assembly may be simplified and the dimensions of the light source assembly may be decreased. 
       FIG. 8  is a cross-sectional view illustrating a modified embodiment of the diffusion lens illustrated in  FIG. 7 . 
     Referring to  FIG. 8 , a diffusion lens  150 - 1  according to the embodiment may further include a dent portion  158  formed on the outer curved surface  157 . That is, the diffusion lens  150 - 1  is partially different from the diffusion lens of  FIG. 7  in that the diffusion lens  150 - 1  according to the embodiment of  FIG. 8  further includes the dent portion  158 . The embodiments of  FIGS. 7 and 8  may be substantially similar in other aspects. 
     The dent portion  158  may be formed in a part corresponding to the light source module  110 . That is, the dent portion  158  may have a concave shape toward the light source module  110  as illustrated in  FIG. 8 , and light that is incident from the bottom may be diffused to have a large emission angle. As a result, a hot spot is decreased, and as a result, luminance distribution uniformity and color uniformity of light may be further improved. 
       FIG. 9  is a cross-sectional view illustrating another embodiment of the diffusion lens illustrated in  FIG. 7 . 
     Referring to  FIG. 9 , a diffusion lens  150 - 2  may further include a flat portion  159  formed on the outer curved surface  157 . That is, the diffusion lens  150 - 2  according to the embodiment of  FIG. 9  is partially different from the diffusion lens of  FIG. 7  in that the diffusion lens  150 - 2  further includes the flat portion  159 . The embodiments of  FIGS. 7 and 9  may be substantially similar in other aspects. 
     The flat portion  159  may be formed, at least in a part, to correspond to the light source module  110  and a plane shape thereof may have a circular shape having a predetermined radius F. The flat portion  159  increases the probability that the light incident from the bottom will be reflected, thereby diffusing light more uniformly. As a result, the luminance distribution uniformity and the color uniformity of the light may be improved. 
       FIG. 10  is a cross-sectional view illustrating a light collecting lens  130  according to an embodiment.  FIG. 11  is a plan view of the light collecting lens  130  illustrated in  FIG. 10 . 
     Referring to  FIGS. 10 and 11 , the light collecting lens  130  according to the embodiment may be configured to incorporate a Fresnel lens  131 . The Fresnel lens  131  may include a first Fresnel lens surface  133   a  facing the light source module  110  and a second Fresnel lens surface  133   b  facing the first Fresnel lens surface  133   a , and each of the Fresnel lens surfaces  133   a  and  133   b  may include concentric patterns as illustrated in FIG.  11 . That is, the first lens surface  130   a  of  FIG. 3  of the light collecting lens  130  may be configured by the first Fresnel lens surface  133   a  and the second lens surface  130   b  of  FIG. 3  may be configured by the second Fresnel lens surface  133   b.    
     The shapes of the first Fresnel lens surface  133   a  and the second Fresnel lens surfaces  133   b  may be symmetric to each other in the horizontal direction as illustrated in  FIG. 10 . However, this is just one embodiment and the shapes may be asymmetric in other embodiments. 
     The light collecting lens  130  collects the light radially emitted from the light source module  110  and provides the collected light to the inner curved surface  157  of the diffusion lens as described above. When the light collecting lens  130  is formed by the Fresnel lens  131 , the size and the thickness of the lens  130  may be reduced and a focal distance may be shortened while a light collecting function is executed. As a result, the thicknesses of the lens module LM and the light source assembly  100  of  FIG. 1  may be reduced. 
     Meanwhile, in  FIG. 10 , the Fresnel lens surfaces  133   a  and  133   b  are formed on both surfaces of the Fresnel lens  131 , but this is just one example and other embodiments may include just one of the Fresnel lens surfaces  133   a  and  133   b . More specifically, the Fresnel lens  131  may include only the first Fresnel lens surface  133   a  or only the second Fresnel lens surface  133   b.    
       FIGS. 12 and 13  illustrate a modified embodiment of the light collecting lens illustrated in  FIG. 10 . 
     Referring to  FIG. 12 , both surfaces of a light collecting lens  130 - 1  according to the embodiment may have a shape of a convex lens. That is, the first lens surface  134   a  facing the light source module  110  may have a convex shape projecting toward the light source module  110  and the second lens surface  134   b  facing the first lens surface  134   a  may have a convex shape projecting toward the inner curved surface  157 . 
     Referring to  FIG. 13 , one surface of a light collecting lens  130 - 2  according to the embodiment may have the shape of a concave lens and the other surface may have the shape of the convex lens. That is, the first lens surface  136   a  facing the light source module  110  may have a concave shape such that the center of the surface  136   a  is farther away from the light source module  110  than the edges, (thereby forming a curve similar to an inner curved surface  157 ). The second lens surface  136   b  facing the first lens surface  136   a  may have the convex shape projecting away from the light source module  110 , toward the inner curved surface  157 . 
     However, the aforementioned arrangement is just one example and the shape of the light collecting lens  130  may be changed to various shapes to implement the light collecting function. 
       FIG. 14  is a cross-sectional view illustrating a light source module according to an embodiment. 
     Referring to  FIG. 14 , the light source module  110  may include a receiving container  111 , a first light source  113 , a second light source  115 , a first resin  117 , and a second resin  119 . 
     The receiving container  111  may include a bottom surface  1110  and a side wall  1130 , and in more detail, the receiving container  111  may have a rectangular parallelepiped shape including the bottom surface  1110  and four side walls  1130 . The receiving container  111  may be made of a mold resin and formed by a injection molding method, but that is not a limitation of the present disclosure. 
     A first light source  113  may be placed on the bottom surface  1110 . The first light source  113  may generate light of a first color and the first color may be a blue color. For example, the first light source  113  may be a blue LED and although not illustrated in the figure, the first light source  113  may have two or more blue LEDs. 
     The second light source  115  may be placed on the bottom surface  1110  may be placed somewhere other than where the first light source  113  is placed. The second light source  115  may generate light of a second color and the second color may be a green color. For example, the second light source  115  may be a green LED and although not illustrated in the figure, the second light source  115  may have two or more green LEDs. 
     Although not explicitly illustrated, an electrode unit for driving the first and second light sources  113  and  115  may be provided in the receiving container  111 . The first and second light sources  113  and  115  may be connected to the electrode unit formed in the receiving container  111  by a connection line. 
     The first resin  117  is formed on the first light source  113  to cover the top and the side of the first light source  113 . In particular, in the embodiment, the first resin  117  may include a fluorescent substances having a third color and the third color may be a red color. The red fluorescent substance may be a nitride or oxynitride based fluorescent substance. 
     The first resin may include at least one of methyl based silicon, phenyl based silicon, and epoxy. As a method of forming the first resin  340 , a method may be used, which mixes the red fluorescent substance with the methyl based silicon, the phenyl based silicon, and the epoxy by using a mixer (not illustrated), degases the mixed resin by using a degaser (not illustrated), and thereafter, sprays the degassed resin onto the first light source  320  by using a dispenser (not illustrated). 
     The light source module  110  may generate mixed light by using the first light source  113 , the second light source  115 , and the fluorescent substance of the first resin  117 , and output the mixed light to the lens module LM of  FIG. 3 . In detail, the first light source  113  may generate blue light and the red fluorescent substance absorbs the blue light to generate red light. The blue light and the red light are mixed on the first resin to generate magenta light. The second light source  115  may generate green light, and the magenta light generated on the first resin  117  is mixed with the green light generated in the second light source  115  to generate the mixed light. 
     Ideally, the mixed light may be white light, but actually, when light is not uniformly mixed, there is a possibility that the color shading will occur. According to the present disclosure, since the light generated from the light source module  110  is collected and then diffused and emitted to the outside by using the lens module LM of  FIG. 3 , color shading may be prevented and color uniformity may improve. 
     The second resin  119  is formed on the first resin  117  and the second light source  115  to cover the top of the first resin  117 , and cover the top and the side of the second light source  115 . 
     The second resin  119  may include at least one of the methyl based silicon, the phenyl based silicon, and the epoxy. As a method of forming the second resin  119 , a method may be used, which sprays the methyl based silicon, the phenyl based silicon, and the epoxy onto the first resin  117  and the second light source  115  by using the dispenser. 
     A refractive index of the first resin  117  may be larger than that of the second resin  119 . 
     When the refractive index of the first resin  117  is smaller than that of the second resin  119 , a component of the light from the second light source  115  may propagate toward the first resin  117  through the second resin  119  and also through the first resin  117 . For example, where the second light source  115  is a green LED chip, the green light would pass through the second resin  119  and the first resin  117 . Accordingly, the light from the second light source  115  may be absorbed by the fluorescent substance of the first resin  117 , reducing the efficiency of the light source module  110 . 
     On the contrary, when the refractive index of the first resin  117  is larger than that of the second resin  119 , light that moves toward the first resin  117  through the second resin  119  may not be able to pass through the first resin  117  easily. For example, where the second light source  115  is a green LED chip, the green light would pass through the second resin  119  but not as easily through the first resin  117 . Accordingly, less of the light from the second light source  115  will be absorbed by the fluorescent substance of the first resin  117 , increasing the efficiency of the light source module  110 . For example, some of the green light emitted from the second light source  115  may be reflected on a boundary surface of the first resin  117  and the second resin  119  to thereby prevent the light from moving to the inside of the first resin  117 . 
       FIG. 15  is a cross-sectional view illustrating a modified embodiment of the light source module illustrated in  FIG. 14 . Referring to  FIG. 15 , a light source module  110 - 1  according to the embodiment is partially different from the light source module  110  of  FIG. 13  in that the light source module  110 - 1  further includes a protrusion portion  1111  formed on the bottom surface  1110 . 
     The protrusion portion  1111  may be positioned between the first light source  113  and the second light source  115 , and the second light source  115  and the first resin  117  may be spatially separated from each other due to the protrusion portion  1111 . 
     Since the red fluorescent substance absorbs a lot of green light in addition to the blue light, the efficiency of the light source module may be reduced. Accordingly, when the red fluorescent substance and the light source emitting the green light are spatially separated from each other, there may be an improvement to the efficiency of the light source module. 
     The presence of the protrusion portion  1111  placed between the first light source  113  and the second light source  115  decreases the contact between the green light emitted from the second light source  115  and the fluorescent substance of the first resin  117  in the light source module  110 - 1 . Hence, the efficiency of the light source module  110 - 1  is increased. 
       FIG. 16  is a cross-sectional view illustrating another modified embodiment of the light source module illustrated in  FIG. 14 . 
     Referring to  FIG. 16 , the light source module  110 - 1  according to the embodiment is partially different from the light source module  110  of  FIG. 10  illustrated in  FIG. 14  in that the light source module  110 - 1  has a first bottom surface  1113  and a second bottom surface  1115  which have different levels. In the embodiment of the light source module  110 - 1  that is shown, the first bottom surface  1113  may be positioned, at least in part, relatively lower than the second bottom surface  1115 . 
     The first light source  113  may be positioned on the first bottom surface  1113  and the second light source  115  may be positioned on the second bottom surface  1115 . In addition, the first resin  117  may cover the top and the side of the first light source  113  and the second resin  119  may cover the top and the side of the second light source  115  and the first resin  117 . The first light source  113 , the second light source  115 , the first resin  117 , and the second resin  119  in the light source module  110 - 2  are substantially the same as in the embodiment of  FIG. 14 . Therefore, a detailed description of those parts will not be repeated. 
     In a light source module  110 - 2  according to the embodiment, since the first light source  113  and the second light source  115  are placed on the bottom surfaces  1113  and  1115  positioned at different levels, the second light source  115  and the first resin  117  may be spatially separated from each other. As a result, the green light emitted from the second light source  115  contacts the fluorescent substance of the first resin  117  at reduced frequency, increasing the efficiency of the light source module  110 - 2 . 
     According to the present disclosure, the light source module and the lens module are joined to each other to configure the light source assembly and the backlight assembly. As a result, the light uniformity improvement and the color uniformity improvement can be achieved, as described above. 
     The foregoing is illustrative of the present inventive concept and is not to be construed as limiting thereof. Although a few embodiments have been described, those skilled in the art will readily appreciate that many modifications are possible in the embodiments without materially departing from the novel teachings and advantages of the present invention. Accordingly, all such modifications are intended to be included within the scope of the present inventive concept. Therefore, it is to be understood that the foregoing is illustrative of the inventive concept presented herein and is not to be construed as limited to the specific embodiments disclosed, and that modifications to the disclosed embodiments, as well as other embodiments, are intended to be included within the scope of the disclosure.