Patent Publication Number: US-11652334-B2

Title: Back side emitting light source array device and electronic apparatus having the same

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. patent application Ser. No. 16/544,390, filed on Aug. 19, 2019 in the United States Patent and Trademark Office, which claims the benefit of U.S. Provisional Application No. 62/721,083, filed on Aug. 22, 2018 in the United States Patent and Trademark Office, and priority to Korean Patent Application No. 10-2019-0043779, filed on Apr. 15, 2019 in the Korean Intellectual Property Office, the disclosures of which are incorporated herein in their entireties by reference. 
    
    
     BACKGROUND 
     1. Field 
     Example embodiments of the present disclosure relate to a back side emitting light source array device that includes a plurality of vertical cavity surface emitting lasers (VCSELs) including nanostructure reflectors and emits light toward a substrate and an electronic apparatus including the back side emitting light source array device. 
     2. Description of the Related Art 
     In recent years, in object recognition with respect to, for example, humans and other objects, it is increasingly necessary to accurately identify the shape, position, and movement of an object through accurate 3-dimensional shape recognition. For example, a laser is often used for a sensor for 3-dimensional shape recognition. 
     Since a vertical cavity surface emitting laser (VCSEL) exhibits lower optical gain lengths than an edge emitting laser (EEL), the VCSEL is advantageous for reduction of power consumption and increased integration. Also, while the EEL exhibits asymmetrical optical output, the VCSEL provides a circular symmetrical output mode, and thus the VCSEL may be efficiently connected to an optical fiber and perform stable high-speed modulation at low noise. 
     The VCSEL includes a distributed Bragg reflector (DBR) exhibiting a high reflectivity of about 90% or higher to constitute a laser resonator. A DBR may include a stacked structure of tens of pairs of two materials with different refractive indices to obtain a high reflectivity. A DBR exhibits low heat conductivity (or high heat resistance) due to phonon scattering occurring at the boundary of two materials. There is a need for a technique and a method capable of improving light control and light emission characteristics while compensating for the disadvantages of the DBR. 
     SUMMARY 
     One or more example embodiments provide a back side emitting light source array device including a plurality of vertical cavity surface emitting lasers (VCSELs) and configured to emit light toward a substrate. 
     One or more example embodiments also provide an electronic apparatus including a back side emitting light source array device including a plurality of VCSELs. 
     Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of example embodiments. 
     According to an aspect of an example embodiment, there is provided a back side emitting light source array device including a substrate, a distributed Bragg reflector (DBR) provided on a first surface of the substrate, a plurality of gain layers which are provided on the DBR, the plurality of gain layers being spaced apart from one another, and each of the plurality of gain layers being configured to individually generate light, and a nanostructure reflector provided on the plurality of gain layers opposite to the DBR, and including a plurality of nanostructures having a sub-wavelength shape dimension, wherein a reflectivity of the DBR is less than a reflectivity of the nanostructure reflector such that the light generated is emitted through the substrate. 
     The back side emitting light source array device may further include a meta-surface layer provided on a second surface of the substrate opposite to the first surface. 
     The meta-surface layer may include a meta lens, a meta-prism, or a meta-diffractive element. 
     The meta-surface layer may have sub-wavelength dimensions and may include a nanostructure with a refractive index that is greater than a reflective index of a material provided around the nanostructure. 
     At least one of a thickness, a width, and an arrangement pitch of each of the plurality of nanostructures of the nanostructure reflector may be less than or equal to half of wavelength of the light, and at least one of a thickness, a width, and an arrangement pitch of each of the plurality of nanostructures of the meta-surface layer may be less than or equal to two-thirds of the wavelength of the light. 
     The back side emitting light source array device may further include a heat sink provided on the nanostructure reflector opposite to the plurality of gain layers. 
     The substrate may include a group III-V semiconductor substrate. 
     A p contact layer may be provided in the nanostructure reflector and a p contact metal may be provided in the p contact layer. 
     The plurality of gain layers may be provided in an n×m matrix array, where n and m are natural numbers, and the p contact metal may be correspondingly provided to overlap two or more columns the n×m matrix array of the plurality of gain layers. 
     The back side emitting light source array device may further include an aperture layer provided on the p contact metal. 
     The back side emitting light source array device may further include an insertion layer provided on the aperture layer. 
     The back side emitting light source array device may further include an n contact layer provided between the DBR and the plurality of gain layers. 
     The back side emitting light source array device may further include dummy gain layers which do not generate light, and n contact metals supported by the dummy gain layers provided at both ends of the DBR, the n contact metals being connected to the n contact layer. 
     The plurality of gain layers may be provided in an n×m matrix array, n and m being natural numbers, and the n contact layer and the n contact metals are correspondingly provided to overlap two or more rows of the n×m matrix array of the plurality of gain layers. 
     The back side emitting light source array device may further include wires provided on the heat sink. 
     The back side emitting light source array device may further include bonding layers provided between the nanostructure reflector and the heat sink. 
     The back side emitting light source array device may further include a heat conduction layer provided between the nanostructure reflector and the heat sink. 
     The back side emitting light source array device may further include a p contact layer provided on the nanostructure reflector, an n contact layer provided between the DBR and the plurality of gain layers, and an insulating protection layer provided between the p contact layer and the n contact layer. 
     According to an aspect of an example embodiment, there is provided an electronic apparatus including a back side emitting light source array device configured to radiate light to a target object, a sensor configured to receive light reflected from the target object, and a processor configured to obtain information regarding the target object based on light received by the sensor, wherein the back side emitting light source array device includes a substrate, a distributed Bragg reflector (DBR) provided on a first surface of the substrate, a plurality of gain layers which are provided on the DBR, the plurality of gain layers being spaced apart from one another, and each of the plurality of gain layers being configured to individually generate light, and a nanostructure reflector provided on the plurality of gain layers opposite to the DBR, and including a plurality of nanostructures having a sub-wavelength shape dimension, wherein a reflectivity of the DBR is less than a reflectivity of the nanostructure reflector such that the light generated is emitted through the substrate. 
     The electronic apparatus may further include a meta-surface layer provided on second surface of the substrate opposite to the first surface. 
     The electronic apparatus may further include a heat sink provided on the nanostructure reflector. 
     The electronic apparatus may further include a p contact layer provided on the nanostructure reflector, and a p contact metal provided on the p contact layer. 
     The plurality of gain layers may be provided in an n×m matrix array, n and m being natural numbers, and the p contact metal is correspondingly provided to overlap two or more columns of the n×m matrix array of the plurality of gain layers. 
     The electronic apparatus may further include an n contact layer provided between the DBR and the plurality of gain layers. 
     The electronic apparatus may further include dummy gain layers which do not generate light, and n contact metals supported by the dummy gain layers provided at both ends of the DBR, the n contact metals being connected to the n contact layer. 
     The plurality of gain layers may be provided in an n×m matrix array, n and m being natural numbers, and the n contact layer and the n contact metals are correspondingly provided to overlap two or more rows of the n×m matrix array of the plurality of gain layers 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and/or other aspects will become apparent and more readily appreciated from the following description of example embodiments, taken in conjunction with the accompanying drawings in which: 
         FIG.  1    is a schematic view of a back side emitting light source array device according to an example embodiment; 
         FIG.  2    is a view of a vertical cavity surface emitting laser (VCSEL) of the back side emitting light source array device shown in  FIG.  1   ; 
         FIG.  3    is a view of a structure including a dummy gain layer of the back side emitting light source array device shown in  FIG.  1   ; 
         FIG.  4    is a view of an example of a nanostructure of a meta-surface layer of the back side emitting light source array device shown in  FIG.  1   ; 
         FIG.  5    is a view of another example of the nanostructure of the meta-surface layer of the back side emitting light source array device shown in  FIG.  1   ; 
         FIGS.  6  to  12    are views of various examples of the nanostructure of the meta-surface layer of the back side emitting light source array device shown in  FIG.  1   ; 
         FIG.  13    is a schematic view of a wiring structure of a back side emitting light source array device according to an example embodiment; 
         FIG.  14    is a schematic view of an example of a wiring structure of a back side emitting light source array device according to an example embodiment; 
         FIG.  15    is a schematic view of another example of a wiring structure of a back side emitting light source array device according to an example embodiment; 
         FIG.  16    is a cross-sectional view, taken along line I-I of  FIG.  15   ; 
         FIG.  17    is a view of a back side emitting light source array device according to another example embodiment; 
         FIG.  18    is a schematic view of an electronic apparatus according to an example embodiment; 
         FIG.  19    is a schematic view of an electronic apparatus according to another example embodiment; and 
         FIG.  20    is a perspective view of an example appearance of the electronic apparatus of  FIG.  19   . 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to example embodiments of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the example embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the example embodiments are merely described below, by referring to the figures, to explain aspects. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list. For example, the expression, “at least one of a, b, and c,” should be understood as including only a, only b, only c, both a and b, both a and c, both b and c, or all of a, b, and c. 
     In the drawings, the size and thickness of each element may be exaggerated for clarity of explanation. While such terms as “first,” “second,” etc., may be used to describe various elements, such elements must not be limited to the above terms. The above terms may be used only to distinguish one element from another. 
     An expression used in the singular encompasses the expression of the plural, unless it has a clearly different meaning in the context. In addition, unless explicitly described to the contrary, the word “comprise” and variations such as “comprises” or “comprising” will be understood to imply the inclusion of stated elements but not the exclusion of any other elements. Also, when it is described that a certain material layer is present on a substrate or other layer, the material layer may be present in direct contact with the substrate or another layer, and there may be another third layer in between. In addition, the materials constituting layers in the following example embodiments are merely examples, and other materials may also be used. 
     In addition, the terms “unit”, “-or”, and “module” described in the specification mean units for processing at least one function and operation and may be implemented by hardware components or software components and combinations thereof. 
     The specific implementations described in example embodiments are illustrative and are not in any way limiting. For clarity of description, descriptions of conventional electronic configurations, control systems, software, and other functional aspects of such systems may be omitted. Also, connections of lines or connecting members between the components shown in the drawings are example illustrations of functional connections and/or physical or circuit connections, which may be replaced with or additionally provided by various functional connections, physical connections, or circuit connections. 
     The use of the terms “the” and similar indication words may refer to both singular and plural. 
     Operations that constitute a method may be performed in any suitable order, unless explicitly stated to be done in an order described. Furthermore, the use of all exemplary terms (e.g., etc.) is merely intended to be illustrative of technical ideas and is not to be construed as limiting the scope of the term unless further limited by the claims. 
       FIG.  1    is a schematic view of a back side emitting light source array device according to an example embodiment. 
     Referring to  FIG.  1   , the back side emitting light source array device may include a substrate  10 , a distributed Bragg reflector (DBR)  20  provided on the substrate  10 , a plurality of gain layers  30  that are arranged on the DBR  20  to be spaced apart from one another, and a plurality of nanostructure reflectors  36  that are provided to be respectively corresponding to the plurality of gain layers  30 . 
     A heat sink  40  for emitting heat to the plurality of nanostructure reflectors  36  may be provided. 
     The substrate  10  may be a semiconductor substrate, e.g., a group III-V semiconductor substrate. However, example embodiments are not limited thereto. 
     The DBR  20 , the plurality of gain layers  30 , and the plurality of nanostructure reflector  36  may constitute a vertical cavity surface emitting laser (VCSEL). The VCSEL is a type of semiconductor laser diode that emits light in a direction perpendicular to the surface of a laser. 
     The DBR  20  may have a structure in which first material layers  21  and second material layers  22  having different refractive indexes are alternately and repeatedly stacked. The reflectivity of the DBR  20  may be adjusted by adjusting at least one of a difference between the refractive indexes of a first material layer  21  and a second material layer  22 , the thicknesses of the first material layer  21  and the thickness of the second material layer  22 , and the number of times that the first material layers  21  and the second material layers  22  are stacked. For example, the first material layers  21  and the second material layers  22  may each have a thickness of a quarter of a desired emission wavelength of light and be alternately and repeatedly stacked. The DBR  20  may include a material that is the same as or similar to a semiconductor material constituting the gain layer  30 . For example, the first material layer  21  may be an Al x Ga (1-x) As layer (where x is 0≤X≤1), and the second material layer  22  may be an Al y Ga (1-y) As layer (where y is 0≤y≤1, x≠y), but example embodiments not limited thereto. The first material layer  21  and the second material layer  22  of the DBR  20  may be undoped layers, but in some examples, the first material layer  21  and the second material layer  22  may be doped layers of certain semiconductor types. The materials constituting the DBR  20  are not limited to those described above, and various materials capable of forming refractive index differences may be used for the first material layer  21  and the second material layer  22 . The DBR  20  may be a type of a flat plate-like mirror layer and may have a plate-like structure to cover the plurality of gain layers  30 . The DBR  20  may be considered as a common mirror layer for the plurality of gain layers  30 . 
     The gain layer  30  is a layer configured to absorb energy to generate light. The gain layer  30  may generate light, for example, by injecting a current or by pumping light. The gain layer  30  may include an active layer  32  including a semiconductor material. The active layer  32  may include, for example, a group III-V semiconductor material or a group II-VI semiconductor material. For example, the active layer  32  may include a multi-quantum well (MQW) structure including indium gallium arsenide (InGaAs), aluminum gallium arsenide (AlGaAs), aluminum gallium nitride (AlGaN), indium gallium arsenide phosphide (InGaAsP), indium gallium phosphide (InGaP), or aluminum gallium indium phosphide (AlGaInP). According to an example embodiment, the active layer  32  may include quantum dots. The materials and the configurations of the active layer  32  are not limited thereto and may vary. A first clad layer  31  and a second clad layer  33  may be further provided below and above the active layer  32 . The first clad layer  31  and the second clad layer  33  may each include an n-type semiconductor material, a p-type semiconductor material, or an intrinsic semiconductor material. The first clad layer  31  and the second clad layer  33  may include the same semiconductor material as the active layer  32  and may further include an n-type dopant or a p-type dopant. 
     The nanostructure reflectors  36  may be arranged in correspondence to the plurality of gain layers  30 , respectively. The nanostructure reflector  36  and the DBR  20  may emit light generated by the gain layer  30  to amplify and output light of a particular wavelength band. For light amplification, the reflectivity of the DBR  20  and the nanostructure reflector  36  may be set to about 90% or higher. For example, the reflectivity of the DBR  20  and the nanostructure reflector  36  may be set to 98% or higher. In an example embodiment, light generated by the gain layer  30  may resonate between the DBR  20  and the nanostructure reflector  36  and then be emitted through the substrate  10 . For example, the DBR  20  may be configured to have a reflectivity lower than that of the nanostructure reflector  36 , and thus light repeatedly reflected between the DBR  20  and the nanostructure reflector  36  may be emitted to the outside through the DBR  20  and the substrate  10 . Therefore, a back side emitting light source array device may be implemented. The reflectivity of the DBR  20  may be adjusted by changing the compositions and thicknesses of the first material layer  21  and the second material layer  22  and the number of times that the first material layer  21  and the second material layer  22  are stacked. The reflectivity of the nanostructure reflector  36  may be adjusted by changing the materials constituting a nanostructure  36   a  and a supporting layer  36   b,  the size of the nanostructure  36   a,  and the arrangement scheme of the nanostructure  36   a,  for example. 
       FIG.  2    is an enlarged view of the VCSEL in  FIG.  1   . Referring to  FIG.  2   , the nanostructure reflector  36  may include a plurality of nanostructures  36   a  having a sub-wavelength dimension. Here, the sub-wavelength dimension may be a thickness or a width, which is a dimension defining the shape of the nanostructure  36   a,  smaller than the operating wavelength of the nanostructure reflector  36 . The operating wavelength of the nanostructure reflector  36  may be within the wavelength band of light generated by the gain layer  30  and may indicate the wavelength λ of light L emitted and emitted between the DBR  20  and the nanostructure reflector  36  in light generated by the gain layer  30 . This may be an emission wavelength λ. 
     The nanostructure  36   a  includes a material having a refractive index higher than those of surrounding materials (e.g., the air) and may be configured to reflect light of a certain wavelength band based on dimensions, particular shapes, and arrangement schemes. The nanostructure  36   a  may have a type of meta-structure. The nanostructure  36   a  may have a meta-structure when at least one of the thickness, the width, and an arrangement pitch of the nanostructure  36   a  it is equal to or less than ½ of the emission wavelength λ. For example, when the width of the nanostructure  36   a  is less than or equal to ½ of the emission wavelength λ, the nanostructure  36   a  may operate as a scattering unit, and as the arrangement pitch becomes less than the emission wavelength λ, light incident on the nanostructure  36   a  may be controlled to have a desired shape without high order diffraction. For example, when the thickness of the nanostructure  36   a  may be less than or equal to ½ of the emission wavelength λ, the nanostructure  36   a  may exhibit a relatively high reflectivity. However, the thickness of the nanostructure  36   a  is not limited thereto. 
     The nanostructure  36   a  may include a dielectric or semiconductor material. For example, the nanostructure  36   a  may include any one of a monocrystalline silicon (Si), a poly-crystalline Si, an amorphous Si, silicon nitride (Si 3 N 4 ), gallium phosphide (GaP), titanium dioxide (TiO 2 ), aluminum antimonide (AlSb), aluminum arsenide (AlAs), aluminum gallium arsenide (AlGaAs), aluminum gallium indium phosphide (AlGaInP), boron phosphide (BP), and zinc germanium diphosphide (ZnGeP 2 ). Alternatively, the nanostructure  36   a  may include a conductive material. As the conductive material, a highly conductive metal material capable of causing surface plasmon excitation may be employed. For example, at least one selected from copper (Cu), aluminum (Al), nickel (Ni), iron (Fe), cobalt (Co), zinc (Zn), titanium (Ti), ruthenium (Ru), rhodium (Rh), palladium (Pd), platinum (Pt), silver (Ag), osmium (Os), iridium (Ir), and gold (Au) may be employed as the conductive material or an alloy including any one of the above-stated metals may be employed as the conductive material. Furthermore, a 2-dimensional material having good conductivity like graphene or a conductive oxide may be employed. Alternatively, a part of the nanostructures  36   a  may include a dielectric material having a high refractive index, and the remaining of the nanostructures  36   a  may include a conductive material. 
     The nanostructure reflector  36  may include the supporting layer  36   b  supporting the plurality of nanostructures  36   a . The supporting layer  36   b  may include a material having a refractive index smaller than the refractive index of the nanostructure  36   a . For example, the supporting layer  36   b  may include SiO 2 , a transparent conductive oxide (TCO), or a polymer like polycarbonate (PC), polystyrene (PS), or polymethyl methacrylate (PMMA). The materials constituting the supporting layer  36   b  are not limited thereto, and in some cases, the supporting layer  36   b  may include a semiconductor material. The supporting layer  36   b  and the nanostructure  36   a  may include the same or similar semiconductor material. For example, both the supporting layer  36   b  and the nanostructure  36   a  may include group III-V semiconductor compounds. Furthermore, by adjusting the composition ratio of the compounds, the refractive index of the supporting layer  36   b  may be made smaller than the refractive index of the nanostructure  36   a . A difference between refractive indexes of the supporting layer  36   b  and the nanostructure  36   a  may be about 0.5 or more. 
     The second clad layer  33  of the gain layer  30  may further include an aperture layer  34  for adjusting the mode or the beam size of emitted light. The aperture layer  34  may include a certain oxide. Here, the aperture layer  34  is illustrated as being formed under the gain layer  30 , but example embodiments are not limited thereto. For example, the aperture layer  34  may be disposed on top of the gain layer  30 . In addition, a plurality of aperture layers  34  may be provided or may be omitted. The aperture layer  34  may further include an insertion layer  35 . The insertion layer  35  may include the same type or similar type of semiconductor materials as the gain layer  30 . The insertion layer  35  may be doped with a certain impurity. 
     When applied to a three-dimensional shape recognition sensor, the VCSEL may emit a laser beam of approximately 850 nm or 940 nm or may emit light in the near-infrared wavelength band. However, the wavelength of emitted light is not particularly limited, and light of a wavelength band needed for an application utilizing structured light may be emitted or light of a wavelength band needed for an application utilizing scan light may be emitted. 
     A first contact layer  25  may be provided between the DBR  20  and the gain layer  30 . The first contact layer  25  may be provided to be corresponding to each of the plurality of gain layers  30 . For example, when the gain layers  30  are arranged in the form of an n×m (n and m are natural numbers) matrix array, the first contact layer  25  may be provided to be corresponding to the gain layer  30  arranged in any one row in common. According to an example embodiment, the first contact layer  25  may be provided to be corresponding to the gain layers  30  arranged in two or more rows in common. First contact layers  25  adjacent to each other may be spaced apart. 
     Referring to  FIG.  1   , dummy gain layers  301  including dummy active layers  321  that do not generate light may be further provided at both ends of the DBR  20 .  FIG.  3    is an enlarged view of the dummy gain layer  301 . Referring to  FIG.  3   , the dummy gain layer  301  may include a first clad layer  31  and a second clad layer  33 . The dummy gain layer  301  may be configured, such that no voltage is applied thereto to generate light. A first contact metal  39  for applying a voltage to the first contact layer  25  may be provided in the dummy gain layer  301 . The first contact metal  39  may be supported by the dummy gain layer  321  and may extend to the first contact layer  25  and be electrically coupled thereto. 
     For example, the first contact layer  25  may be an n contact layer and the first contact metal  39  may be an n contact metal. However, example embodiments are not limited thereto, and the first contact layer  25  may be a p contact layer and the first contact metal  39  may be a p contact metal. The first contact layer  25  may include a transparent conductive material through which light may be transmitted. A second contact layer  28  may be provided on the other surface of the gain layer  30 . A second contact metal  38  for applying a voltage to the second contact layer  28  may be provided. For example, the second contact layer  28  may be a p contact layer and the second contact metal  38  may be a p contact metal. The second contact layer  28  may be provided adjacent to the nanostructure reflector  36 . Since the second contact layer  28  is not connected to the second contact metal  38 , no voltage is supplied to the dummy gain layer  301 , and thus no light is generated. 
     An insulating protection layer  37  for electrical isolation may be further provided between the first contact layer  25  and the second contact metal  38  or between the first contact layer  25  and the second contact layer  28 . When the gain layers  30  are arranged in the form of an n×m (n and m are natural numbers) matrix array, the second contact metal  38  may be coupled to the second contact layers  28 , which are provided in correspondence to the gain layers  30  arranged in any one row, in common. Furthermore, the second contact layers  28  provided in each column may be arranged to be apart from one another. An electrical wiring structure will be described later. 
     When power is turned on through the first contact metal  39  and the second contact metal  38 , light is generated by the gain layer  30 . The light may be resonated between the DBR  20  and the nanostructure reflector  36  and emitted to the outside through the substrate  10 . 
     Referring to  FIG.  1   , a meta-surface layer  15  may be further provided on the other surface of the substrate  10 . The meta-surface layer  15  may include a meta-lens, a meta-prism, or a meta-diffractive element. 
     The meta-surface layer  15  may have sub-wavelength dimensions and may include nanostructures  15   a  having a relatively high refractive index and a material having a relatively low refractive index around the nanostructures  15   a . The nanostructures  15   a  may be provided on the supporting layer  15   b . For example, at least one of the thickness, the width, and the arrangement pitch of the nanostructures  36   a  of the nanostructure reflector  36  has a numerical value less than or equal to half of the wavelength of light, and at least one of the thickness, the width, and the arrangement pitch of the nanostructures  15   a  of the meta-surface layer  15  may have a numerical value equal to or less than two-thirds of the wavelength of light. However, it is merely an example, and example embodiments are not limited thereto. 
     The nanostructures  15   a  may include a dielectric or semiconductor material. For example, the nanostructures  15   a  may include any one of a monocrystalline silicon, a poly-crystalline Si, an amorphous Si, Si 3 N 4 , GaP, TiO 2 , AlSb, AlAs, AlGaAs, AlGaInP, BP, and ZnGeP 2 . According to an example embodiment, the nanostructures  15   a  may include a conductive material. As the conductive material, a highly conductive metal material capable of causing surface plasmon excitation may be employed. For example, at least one selected from Cu, Al, Ni, Fe, Co, Zn, Ti, Ru, Rh, Pd, Pt, Ag, Os, Ir, and Au may be employed as the conductive material or an alloy including any one of the above-stated metals may be employed as the conductive material. Furthermore, a two-dimensional material having good conductivity like graphene or a conductive oxide may be employed. According to an example embodiment, some of the nanostructures  15   a  may include a dielectric material having a relatively high refractive index, and the rest of the nanostructures  15   a  may include a conductive material. 
     The supporting layer  15   b  may include a material having a refractive index smaller than the refractive index of the nanostructure  15   a . For example, the supporting layer  15   b  may include SiO 2 , a transparent conductive oxide (TCO), or a polymer like polycarbonate (PC), polystyrene (PS), or polymethyl methacrylate (PMMA). The materials constituting the supporting layer  15   b  are not limited thereto, and in some cases, the supporting layer  15   b  may include a semiconductor material. The supporting layer  15   b  and the nanostructure  15   a  may include the same or similar semiconductor material. For example, both the supporting layer  15   b  and the nanostructure  15   a  may include group III-V semiconductor compounds. Furthermore, by adjusting the composition ratio of the compounds, the refractive index of the supporting layer  15   b  may be made smaller than the refractive index of the nanostructure  15   a . A difference between refractive indexes of the supporting layer  15   b  and the nanostructure  15   a  may be about 0.5 or more. However, example embodiments are not limited thereto. 
       FIG.  4    is a perspective view of an example of the meta-surface layer in  FIG.  1   . 
     Referring to  FIG.  4   , the meta-surface layer  151  may include the supporting layer  151   b  and a plurality of nanostructures  151   a  provided on the supporting layer  151   b.    FIG.  4    shows an example in which the nanostructures  151   a  are arranged in a rectangular lattice-like shape, but example embodiments are not limited thereto. The nanostructure  151   a  may have any of various shapes like a cylindrical shape, an elliptical column-like shape, and a rectangular column-like shape. Here, the case where the nanostructure  151   a  has a cylindrical shape is shown. The nanostructures  151   a  may be arranged, for example, in a radial shape. 
       FIG.  5    is a cross-sectional view of another example of a meta-surface layer in  FIG.  1   . 
     Referring to  FIG.  5   , a meta-surface layer  151  may include the supporting layer  151   b  and a plurality of nanostructures  151   a  provided in the supporting layer  151   b .  FIG.  5    shows an example in which the nanostructures  151   a  are arranged in a rectangular lattice-like shape. In addition, the nanostructures  151   a  may also be arranged in a hexagonal lattice-like shape, and the arrangement shape may vary. Further, the meta-surface layer  151  may include another supporting layer  151   c.    
       FIG.  6    is a perspective view of the structure of a nanostructure that may be applied to another example of a meta-surface layer . 
     Referring to  FIG.  6   , a nanostructure  152  may have a major axis in a first direction, e.g., an X-axis direction on an XY plane, and a minor axis in a second direction, e.g., a Y-axis direction. The dimension in the major axis direction may be referred to as a length L, whereas the dimension in the minor axis direction may be referred to as a width W. On the other hand, the dimension in a Z-axis direction may be referred to as a thickness T or a height H. The length L may be greater than the width W, and the nanostructure  152  may have an elliptical shape or a shape similar thereto on the XY plane. It may be said that the nanostructure  152  has an anisotropic structure. 
     The width W, the length L, and/or the thickness T of the nanostructure  152  may be less than or equal to half of the emission wavelength λ. Also, when the nanostructures  152  are arranged regularly, an interval between two nanostructures  152  adjacent to each other, for example, an interval between the centers of the two nanostructures  152  may be equal to or less than two-thirds of the emission wavelength λ. 
     The anisotropic structure of the nanostructure  152  may vary widely. For example, the nanostructure  152  may have an anisotropic structure other than an elliptical shape on the XY plane. Examples thereof are shown in  FIGS.  7  and  8   . 
     Referring to  FIG.  7   , the nanostructure  153  may have a rectangular column-like shape. The nanostructure  153  may have a rectangular anisotropic structure on the XY plane. 
     Referring to  FIG.  8   , the nanostructure  154  may have a cross-shaped column structure. At this time, the length L in the X-axis direction may be greater than the width W in the Y-axis direction. Therefore, it may be said that the nanostructure  154  has an anisotropic structure. 
     As described above with reference to  FIGS.  6  to  8   , when the nanostructures  152 ,  153 , and  154  have anisotropic structures, the polarization direction of light incident on the nanostructures  152 ,  153 , and  154  may be controlled by using arrays of the nanostructure  152 ,  153 , and  154 . By arranging the nanostructures  152 ,  153  and  154  having anisotropic structures in a particular direction, light incident on the nanostructures  152 ,  153 , and  154  may be controlled to be polarized in a particular direction. However, the structures of the nanostructure  152 ,  153 , and  154  are merely examples, and various modifications may be made therein. 
     According to example embodiments, the meta-surface layer  15  may be designed to be used as a meta-lens, a meta-prism, or a meta-diffractive element. The size distribution and the arrangement rule of a plurality of nanostructures constituting the meta-surface layer  15  may be designed, such that the meta-surface layer  15  serves as a concave lens, a convex lens, a prism, or a diffractive element. 
       FIG.  9    is a cross-sectional view of a schematic structure of a nanostructure of a meta-surface layer according to another example embodiment. 
     Referring to  FIG.  9   , a meta-surface layer  155  may include a supporting layer  155   a  and a plurality of nanostructures  155   b  provided on the supporting layer  155   a . The size distribution and the arrangement rule of a plurality of nanostructures  155   b  may be designed, such that the meta-surface layer  155  serves as a concave lens. For example, the width W of the plurality of nanostructures  155   b  may increase as a distance d from the center of the meta-surface layer  155  increases. When the position of the nanostructure  155  is defined as the distance d from the center of the meta-surface layer  155 , the width W of the nanostructure  155   b  at a given position may be set to a particular value, such that the meta-surface layer  155  operates as a concave lens or a convex lens. As the distance d from the center of the meta-surface layer  155  increases, the width W of the nanostructure  155   b  may increase. 
     In another example, the variation rule of the width W of the nanostructure  155  described in  FIG.  9    may be repeated. An example thereof is shown in  FIG.  10   . 
     Referring to  FIG.  10   , a meta-surface layer  156  may include a supporting layer  156   a  and a plurality of nanostructures  156   b,  wherein the width W of the plurality of nanostructures  156   b  may increase in a direction away from the center of the meta-surface layer  156  according to a certain rule. The meta-surface layer  156  may be divided into a plurality of regions according to distances in the direction away from a center O, and the width W of the plurality of nanostructures  156   b  in the plurality of regions may increase in the direction away from the center O. Here, the case where the width W increases from the center (d=0) to a position R 1  and the width W increases again as the distance d increases from the position R 1 . A period in which the rule of increasing the width W is repeated may vary. The meta-surface layer  156  may serve as a concave lens or a convex lens. 
     When the meta-surface layers  155  and  156  serves as a concave lens or convex lens, light emitted from one or more VCSELs may have a particular shape and a particular intensity distribution on a space of interest. By setting the focal distances of the meta-surface layers  155  and  156  that serve as concave lenses or convex lenses close to emission surfaces of VCSELs, light beams emitted from the VCSELs may be emitted at different angles with particular degrees of divergence or collimation. Accordingly, an illumination pattern on a space of interest may be adjusted. Also, by using methods to be described below with reference to  FIGS.  13  to  17   , a plurality of VCSELs may be sequentially driven one or a few at a time according to the time for illumination for scanning a space of interest as desired according to the time. The optical characteristics of the meta-surface layers  155  and  156  may be controlled by adjusting the size distribution and the arrangement rule of a plurality of nanostructures constituting the meta-surface layers  155  and  156 , and thus beam forming and beam shaping of emitted light may be possible. 
       FIG.  11    is a cross-sectional view of a schematic structure of a meta-surface layer according to another example embodiment. 
     Referring to  FIG.  11   , a meta-surface layer  157  may include a supporting layer  157   a  and a plurality of nanostructures  157   b  provided on the supporting layer  157   a.  The size distribution and the arrangement rule of a plurality of nanostructures  157   b  may be designed, such that the meta-surface layer  155  serves as a concave lens or a convex lens. For example, the width W of the plurality of nanostructures  157   b  may decrease as a distance d from the center of the meta-surface layer  157  increases. As the distance d from the center O of the meta-surface layer  157  increases, the width W of the nanostructure  157   b  may increase. 
     The variation rule of the width W of the nanostructure  157   b  described above with reference to  FIG.  11    may be repeated. An example thereof is shown in  FIG.  12   . 
     Referring to  FIG.  12   , a meta-surface layer  158  may include a supporting layer  158   a  and a plurality of nanostructures  158   b,  wherein the width W of the plurality of nanostructures  158   b  may decrease in a direction away from the center O of the meta-surface layer  158  according to a certain rule. The meta-surface layer  158  may be divided into a plurality of regions according to distances in the direction away from a center O, and the width W of the plurality of nanostructures  158   b  in the plurality of regions may decrease in the direction away from the center O. A period in which the rule of decreasing the width W is repeated may vary . The meta-surface layer  158  may serve as a convex lens or a concave lens. In a manner similar to that described above with reference to  FIG.  10   , a space of interest may be illuminated in various ways. 
     The dimensions and the arrangement of a plurality of nanostructures may be set, such that a meta-surface layer is configured to deflect incident light. The arrangement rule and the size distribution of a plurality of nanostructures may be set, such that the width or the size of the plurality of nanostructures gradually decreases or increases in one direction, for example, a horizontal direction. Also, a corresponding arrangement may be repeated on a 2-dimensional surface as one period unit. According to an example embodiment, the width and the size of a plurality of nanostructures may be randomly set in one direction, for example, a horizontal direction. The meta-surface layer  15  may be employed in a VCSEL, may be variously adjusted to control the optical performance of emitted light, e.g., a beam diameter, convergence/divergence/collimation shapes, and orientation, and may also be adjusted to control polarization direction of the emitted light. Meanwhile, the nanostructures described above with reference to  FIGS.  4  to  12    may also be applied to the nanostructure reflector  36 . 
       FIG.  13    is a schematic plan view of a wiring structure of a back side emitting light source array device according to an example embodiment. 
     Referring to  FIG.  13   , a back side emitting light source array device may include an active area A 100  in which a plurality of VCSELs V 10  are arranged. The active area A 100  may include a plurality of first wires W 10  and a plurality of second wires W 20  electrically connected to the plurality of VCSELs V 10 . For example, the first wires W 10  may correspond to first contact metals, and the second wires W 20  may correspond to second contact metals. The back side emitting light source array device may further include a first driver D 10  electrically connected to the plurality of first wires W 10  and a second driver D 20  electrically connected to the plurality of second wires W 20 . When a voltage is applied to any one of the first wires W 10  by the first driving unit D 10  and a voltage is applied to any one of the second wires W 20  by the second driving unit D 20 , light may be emitted by a VCSEL at a point where a first wire W 10  and a second wire W 20  to which voltages are applied. In an example embodiment, the first wires W 10  and the second wires W 20  may be provided in a heat sink  40  (in  FIG.  1   ). 
       FIG.  14    is a schematic plan view of a wiring structure of a back side light emitting array according to an example embodiment. 
     Referring to  FIG.  14   , a plurality of first contact metal patterns r 1  to r 8  extending in a first direction (A direction) and a plurality of second contact metal patterns c 1  to c 13  extending in a second direction (B direction) intersecting the first direction (A direction) may be provided in the heat sink  40 . The plurality of first contact metal patterns r 1  to r 8  may be arranged to be apart from one another. The plurality of second contact metal patterns c 1  to c 13  may be arranged to be apart from one another. The plurality of first contact metal patterns r 1  to r 8  may be row wires, whereas the plurality of second contact metal patterns c 1  to c 13  may be column wires. Each of the first contact metal patterns r 1  to r 8  may include a first contact layer  25  (in  FIG.  1   ) and a first contact metal  39  (in  FIG.  1   ). Each of the second contact metal patterns c 1  to c 13  may include a second contact layer  28  (in  FIG.  1   ) and a second contact metal  38  (in  FIG.  1   ). The number of the plurality of first contact metal patterns r 1  to r 8  and the number of the plurality of second contact metal patterns c 1  to c 13  are merely examples and may vary. VCSELs V 20  may be disposed at points where the plurality of first contact metal patterns r 1  to r 8  and the plurality of second contact metal patterns c 1  to c 13  intersect. Dummy gain layers V 30  may be provided on both sides of the plurality of first contact metal patterns r 1  to r 8 . 
     The VCSEL V 20  may be operated in either individually (two dimensional operation) or line-by-line (one-dimensional operation) according to a cathode operating point and an anode operating point. For example, when the VCSELs V 20  are indicated as matrixes, a VCSEL (1,1) is turned on when power is applied to a first contact metal pattern r 1  and a second contact metal pattern c 1  and a VCSEL (2,1) is turned on when power is applied to the first contact metal pattern r 1  and a second contact metal pattern c 2 . Accordingly, the VCSELs V 20  may be driven individually and controlled two-dimensionally. The VCSELs V 20  may be operated line-by-line and driven one-dimensionally. For example, when a first row of the first contact metal pattern r 1  is turned on and the second contact metal patterns c 1 -c 13  are selectively turned on and off simultaneously, the first row of the contact metal pattern r 1  may be operated. When a second row of a first contact metal pattern r 2  is turned on and the second contact metal patterns c 1 -c 13  are selectively turned on and off simultaneously, the second row of the contact metal pattern r 2  may be operated. When the first contact metal patterns r 1  to r 8  may be selectively turned on and off simultaneously and a first column of the second contact metal pattern c 1  is turned on, the first column of the second contact metal pattern may be operated. When the first contact metal patterns r 1  to r 8  may be selectively turned on and off simultaneously and a second column of the second contact metal pattern c 2  is turned on, the second column of the second contact metal pattern c 2  may be operated. Accordingly, line-by-line emission control may be performed. 
     A method of operating a back side emitting light source array device shown in  FIG.  14    will be described below. 
     An individual VCSEL operation method is performed as VCSEL(1,1) ON: r 1  ON and c 1  ON, VCSEL(1,2) ON: r 1  ON and c 2  ON, . . . , VCSEL(8,13) ON: r 8  ON and c 13  ON. A line-by-line VCSEL operation method is performed as VCSEL(1 row) ON: r 1  ON and c 1 ˜c 13  ON, VCSEL(2 row) ON: r 2  ON and c 1 ˜c 13  ON, . . . , VCSEL(8 row) ON: r 8  ON and c 1 ˜c 13  ON. Another line-by-line VCSEL operation method is performed as VCSEL(1 column) ON: r 1 ˜r 8  ON and c 1  ON, VCSEL(2 column) ON: r 1 ˜r 8  ON and c 2  ON, . . . , VCSEL(13 column) ON: r 1 ˜r 8  ON and c 13  ON. 
     As described above, in the individual VCSEL operation method, a plurality of VCSELs may be operated individually. In the line-by-line operation method, rows of VCSELs may be operated sequentially or columns of VCSELs may be operated sequentially. In each of the methods, the operating sequences may vary. 
     By electrically controlling emission of VCSELs as described above, back side emitting light source array devices according to example embodiments may be employed in a scanner for scanning light or in a structured light projector. For example, light may be scanned by controlling VCSELs to sequentially emit light and controlling traveling direction of light by using the meta-surface layer  15 . The structured light may be formed by controlling VCSELs to simultaneously emit light and forming patterned light by using the meta-surface layer  15 . A three-dimensional image of a target object may be obtained by using a scanner or a structured light projector. 
     Next,  FIG.  15    is a view of the wiring structure of a back side emitting light source array device according to another example embodiment. 
     Referring to  FIG.  15   , a plurality of first contact metal pattern groups R 1  to R 5  extending in the first direction (A direction) and a plurality of second contact metal pattern groups C 1  to C 6  extending in the second direction (B direction) intersecting the first direction (A direction) may be provided in the heat sink  40 . The plurality of first contact metal row groups R 1  to R 5  may include a plurality of row wires in common, and the plurality of second contact metal column groups C 1  to C 6  may include a plurality of column wires in common. For example, the plurality of row wires included in the first contact metal row group R 1  to R 5  may operate as one cathode (one n-type contact layer), and the plurality of column wires included in the second contact metal column group may operate as one anode (one p-type contact layer). The number of the plurality of the first contact metal row groups R 1  to R 5 , the number of the plurality of row wires included in the plurality of first contact metal row groups R 1  to R 5 , the number of the plurality of second contact metal column groups C 1  to C 6 , and the number of the plurality of column wires included in the plurality of second contact metal column groups C 1  to C 6  are merely examples and may vary. The plurality of VCSELs V 20  may be disposed at points where the plurality of first contact metal pattern groups R 1  to R 5  and the plurality of second contact metal pattern groups C 1  to C 6  intersect. The dummy gain layers V 30  may be provided in correspondence to the plurality of first contact metal pattern groups R 1  to R 5 , respectively. 
       FIG.  16    is a view of a back side emitting light source array device to which the wiring structure of  FIG.  15    is applied.  FIG.  16    shows a structure corresponding to a cross-section taken along the line I-I in  FIG.  15   . In  FIG.  16   , detailed descriptions of components denoted by the same reference numerals as those in  FIG.  1    will be omitted. The gain layers  30  may be arranged as an n×m (n and m are natural numbers) matrix array, and a second contact metal  381 , e.g., a p contact metal, may be provided in correspondence to two or more columns of gain layer groups in common. Also, the first contact layer  25 , e.g., an n contact layer, and a first contact metal  391 , e.g., an n contact metal, may be provided in correspondence to two or more rows of gain layer groups in common. 
     Referring to  FIG.  16   , the second contact metal  381  may have a structure corresponding to the gain layers  30  disposed in three columns in common. The first contact metal  391  may have a structure corresponding to the gain layers  30  disposed in three rows and dummy gain layers  301  disposed in three rows in common. 
     A method of operating a back side emitting light source array device shown in  FIG.  15    will be described below. 
     An individual VCSEL group operation method is performed as VCSEL(1,1) Group ON: R 1  ON and C 1  ON, VCSEL(1,2) Group ON: R 1  ON and C 2  ON, . . . , VCSEL(5,6) Group ON: R 5  ON and C 6  ON. A line-by-line VCSEL group operation method is performed as follows: VCSEL(1 row Group) ON: R 1  ON and C 1 ˜C 6  ON, VCSEL(2 row Group) ON: R 2  ON and C 1 ˜C 6  ON, . . . , VCSEL(5 row Group) ON: R 5  ON and C 1 ˜C 6  ON. A line-by-line VCSEL group operation method is performed as follows: VCSEL(1 column Group) ON: R 1 ˜R 5  ON and C 1  ON, VCSEL(2 column Group) ON: R 1 ˜R 5  ON and C 2  ON, . . . , VCSEL(6 column Group) ON: R 1 ˜R 5  ON and C 6  ON. 
     In this way, the grouping of the row wire and the column wire may enable faster electric driving. 
       FIG.  17    is a view of a back side emitting light source array device according to another example embodiment. 
     Referring to  FIG.  17   , the back side emitting light source array device of  FIG.  17    differs from that of  FIG.  1    in that at least one layer is further provided between the nanostructure reflector  36  and the heat sink  40 . Only the difference will be described below with reference to  FIG.  17   , and descriptions of components denoted by the same reference numerals as those in  FIG.  1    will be omitted. 
     A bonding layer  51  may further be provided between the nanostructure reflector  36  and the heat sink  40 . The bonding layer  51  may include a metal. An insulation layer  53  may further be provided between the bonding layer  51  and the heat sink  40 . Furthermore, a heat conduction layer  55  may further be provided between the insulation layer  53  and the heat sink  40 . The heat conduction layer  55  may allow heat generated by VCSELs to be efficiently dissipated toward the heat sink  40 . 
     Since a back side emitting light source array device according to example embodiments emits light through the substrate  10 , the back side emitting light source array device may include the heat sink  40  having a wire structure coupled to the nanostructure reflector  36 , and thus heat generated by VCSELs may be more efficiently discharged. Therefore, errors and deterioration of life span due to heat generation may be reduced or resolved. Furthermore, a back side emitting light source array device may be easily fabricated through a semiconductor process without limitation according to light emission direction. Furthermore, since VCSELs may contribute to miniaturization, improved operation speed, and reduction of power consumption of a back side emitting light source array device and diversify the optical properties of emitted light, the back side emitting light source array device including VCSELs may be employed in various fields including optical sensors and photonic integrated circuit (IC) systems and may also be applied to various other electronic apparatuses and optical apparatuses. 
       FIG.  18    is a block diagram showing a schematic structure of an electronic apparatus (optical apparatus) according to an embodiment. 
     Referring to  FIG.  18   , an electronic apparatus according to an example embodiment may include a light source  1000  that irradiates light L 10  toward a target object OBJ and a sensor  2000  that detects light L 20  emitted from the light source  1000  and modulated by the target object OBJ. Here, the light source  1000  may include a back side emitting light source array device according to example embodiments. Also, the electronic apparatus may further include an analyzer  3000  for analyzing light detected by the sensor  2000  and analyzing at least one of the physical property, the shape, the position, and the movement of the target object OBJ. 
     Between the light source  1000  and the target object OBJ, optical elements that perform additional operations like adjusting orientation of light generated by the light source  1000  toward the target object OBJ, adjusting the beam size, or modulating light into patterned light may be further arranged. When a meta-surface layer  15  (in  FIG.  1   ) provided in the light source  1000  is suitably designed to perform such operations, such optical elements may be omitted. The sensor  2000  senses the light L 20  modulated (reflected) by the target object OBJ. The sensor  2000  may include an array of light detecting elements. The sensor  2000  may further include a spectroscopic element for analyzing the light L 20  modulated (reflected) by the target object OBJ by wavelengths. 
     The analyzer  3000  may analyze at least one of the physical properties, the shape, the position, and the movement of the target object OBJ by analyzing the light received by the sensor  2000 . The  3 D shape, the position, and the movement of the target object OBJ may be analyzed by comparing the pattern of the light L 10  irradiated to the target object OBJ with the pattern of the light L 20  reflected by the target object OBJ. The material property of the target object OBJ may be analyzed by analyzing the wavelength of light excited by the target object OBJ due to incident light, for example, the light L 10 . 
     The electronic apparatus according to the example embodiment may further include a controller for controlling the operation of the light source  1000  or the operation of the sensor  2000  and may further include a memory in which a calculation program for extraction of 3-dimensional information to be performed by the analyzer  3000  is stored. Information regarding a calculation result of the analyzer  3000 , that is, the shape, the position, the material properties, etc. regarding the target object OBJ may be transmitted to another unit. For example, the information may be transmitted to a controller of a device in which the electronic apparatus is employed. 
     The electronic apparatus according to an example embodiment may also be used as a sensor for precisely obtaining 3-dimensional information regarding a front object, and thus the electronic apparatus may be employed in various devices. Such devices may include, for example, autonomous operating devices like an unmanned vehicle, an autonomous driving vehicle, a robot, and a drone and may also include augmented reality devices, mobile communication devices, Internet of Things (IOT) devices, etc. 
     The configuration of the electronic apparatus (optical apparatus) described with reference to  FIG.  17    is merely an example, and a back side emitting light source array device according to example embodiments may be applied to various electronic apparatuses (optical apparatuses). A back side emitting light source array device may be applied to various fields like imaging devices, projectors, scanners, and sensors. 
     Back side emitting light source array devices of the example embodiments may be employed in various electronic apparatuses for illuminating a target object through a display panel. 
       FIG.  19    is a block diagram showing a schematic configuration of an electronic device according to an example embodiment. 
     An electronic apparatus  4000  may include a display  4100  that radiates light Li toward the target object OBJ, a sensor  4300  that receives light Lr reflected by the target object OBJ, and a processor  4200  that performs a calculation for obtaining information regarding the target object OBJ from the light received from the sensor  4300 . The display  4100  may include a back side emitting light source array device  4110  for irradiating light and a display panel  4120  for displaying an image. 
     The electronic device  4000  may also include a memory  4400  in which code or data for the calculation of the processor  4200  is stored. 
     Light L emitted from the back side emitting light source array device  4110  may illuminate the target object OBJ through a transmission window of the display panel  4120 . 
     The back side emitting light source array device  4110  may illuminate or scan the target object OBJ with structured light. The sensor  4300  senses the light Lr reflected by the target object OBJ. The sensor  4300  may include an array of light detecting elements. The sensor  4300  may further include a spectroscopic element for analyzing light reflected by the target object OBJ by wavelengths. 
     The processor  4200  performs a calculation for obtaining information regarding the target object OBJ from light received from the sensor  4300  and may also manage processing and control of the entire electronic apparatus  4000 . The processor  3200  may obtain and process information regarding the target object OBJ, e.g., two-dimensional or three-dimensional image information, and may also control the operation of the back side emitting light source array device  4110  the operation of the sensor  4300  overall. The processor  4200  may also determine whether a user is authenticated or the like based on information obtained from the target object OBJ and may also execute other applications. 
     The memory  4400  may store a code for execution in the processor  4200  and may also store various execution modules to be executed by the electronic apparatus  4000  and data therefor. For example, the memory  4400  may store program code used by the processor  4200  for an calculation for obtaining information regarding the target object OBJ and code like application modules that may be executed by using the information regarding the target object OBJ. Also, the memory  4400  may further store a communication module, a camera module, a moving image playback module, an audio playback module, and the like as programs for operating devices that may be additionally provided in the electronic device  4000 . 
     A result of an calculation by the processor  4200 , that is, information regarding the shape and the position of the target object OBJ, may be transmitted to another device or another unit as occasions demand. For example, information regarding the target object OBJ may be transmitted to a controller of another electronic device using the information regarding the target object OBJ. The other unit to which a result of an calculation is transmitted may be a display device or a printer that outputs the result. In addition, the other unit may be, but is not limited to, a smartphone, a mobile phone, a personal digital assistant (PDA), a laptop personal computer (PC), a desktop PC, various wearable devices, and other mobile or stationary computing devices. 
     The memory  4400  may include at least one type of storage medium from among a flash memory, a hard disk, a multimedia card micro, a card type memory (e.g., an SD or XD memory), random access memory (RAM), static RAM (SRAM), a read-only memory (ROM), electrically erasable programmable ROM (EEPROM), programmable ROM (PROM), a magnetic memory, a magnetic disk, an optical disk, etc. 
     For example, the electronic device  4000  may be, but is not limited to, a portable mobile communication device, a smart phone, a smartwatch, a PDA, a laptop PC, a desktop PC, and other mobile or stationary computing devices. The electronic device  4000  may be an autonomously operating device like an unmanned vehicle, an autonomous driving vehicle, a robot, and a drone or an Internet-of-Things (IoT) device. 
       FIG.  20    is a perspective view of an example of the electronic apparatus of  FIG.  19   . 
     As shown in  FIG.  20   , the electronic device  4000  may employ a full-screen display type display. For example, the electronic device  4000  may be a bezel-less type in which a display surface  4100   a  occupies almost the entire region of the front surface of the electronic device  4000 . Also, the shape of the display surface  4100   a  may be a rectangular shape without a notch. 
     As described above, a back side emitting light source array device according to example embodiments may be disposed on the rear surface of a display panel and illuminate the front surface of the display panel through a transmitting window uniformly distributed throughout a display surface or a transmitting window formed in one region having a certain size. Therefore, a bezel-less and notch-free display as shown in  FIG.  16    may be applied to the electronic device  4000 . 
     The implementations described in example embodiment are illustrative and do not in any way limit the scope of the present disclosure. For clarity of description, descriptions of conventional electronic configurations, control systems, software, and other functional aspects of such systems may be omitted. Also, connections of lines or connecting members between the components shown in the drawings are example illustrations of functional connections and/or physical or circuit connections, which may be replaced with or additionally provided by various functional connections, physical connections, or circuit connections. 
     It should be understood that example embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each example embodiment should typically be considered as available for other similar features or aspects in other embodiments. 
     While example embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope as defined by the following claims.