Patent Publication Number: US-2019194533-A1

Title: Quantum dot composition, preparation method thereof and device using the composition

Description:
TECHNICAL FIELD 
     The present disclosure relates to a quantum dot composition in which quantum dots are applied to a random raising composite with a maximized barrier property, a preparation method thereof, and a device using the composition. 
     BACKGROUND ART 
     A Liquid Crystal Display (LCD) is a device that converts various electrical information generated from various devices to visual information by using changes in transmittance of liquid crystal according to applied voltages and transmits the visual information. 
     The LCD is widely used since it has low consumption power and can be implemented as a lightweight, thin device. However, the LCD is poor in view of color reproduction property and total brightness property. Recently, a technique of using a Quantum Dot (QD) device to improve the color reproduction property and brightness property of LCD has been proposed. 
     The QD device can be applied to a LCD by a method of applying a quantum dot material in the insides of blue light-emitting device packages, a method of inserting a tube type quantum dot device into an edge type LCD, a method of disposing a sheet type quantum dot device on a light guide plate, etc. 
     However, the quantum dot devices applied to the above-described methods are vulnerable to oxygen and water, and accordingly, they need to use a special barrier film. Meanwhile, in order to overcome the problem, a method of coating quantum dots with silica has been developed. However, when quantum dots are coated with silica, the efficiency of the quantum dots deteriorates. Also, since the size of a quantum dot is within the range of 1% of a visible light wavelength, a large number of quantum dots need to be used to increase the portion of quantum dots that are excited by light-emitting devices. 
     DISCLOSURE 
     Technical Problem 
     One aspect of the present disclosure is directed to providing a quantum dot composition including metal oxide having a structure in which quantum dots are impregnated in pores formed in the surface, a method of preparing the quantum dot composition, and a device using the quantum dot composition. 
     Further, the present disclosure is directed to providing a quantum dot composition in which metal oxide has a size of a Mie scattering range with respect to blue light, a method of preparing the quantum dot composition, and a device using the quantum dot composition. 
     Furthermore, the present disclosure is directed to providing a quantum dot composition in which coating films are formed on the surfaces of quantum dots impregnated in the pores of metal oxide, a method of preparing the quantum dot composition, and a device using the quantum dot composition. 
     Technical Solution 
     One aspect of the present disclosure provides a quantum dot composition including a metal oxide composite, wherein quantum dots are impregnated in pores formed in a surface of the metal oxide composite, wherein the metal oxide composite has a size of a Mie scattering range with respect to blue light. 
     Also, the metal oxide composite may have a size of 100 nm to 1000 nm. 
     Also, the metal oxide composite may include at least one metal oxide selected from among a metal oxide group including titanium oxide (TiO 2 ), aluminum oxide (Al 2 O 3 ), zinc oxide (ZnO), silicon dioxide (SiO 2 ), chrome oxide (CrO), zirconium oxide (ZrO 2 ), iron oxide (Fe 3 O 4 ), calcium oxide (CaO), tungsten dioxide (WO 2 ), tellurium dioxide (TeO 2 ), magnesium oxide (MgO), tin oxide (SnO), titanium oxide (TiO), zinc oxide (Ag 2 O), cobalt oxide (CoO), nickel oxide (NiO), and aluminum oxide (AlO). 
     Also, polymer coating films may be formed on surfaces of the quantum dots. 
     Also, the pores of the metal oxide composite may have a volume ratio of 5 to 65 with respect to a total volume of the metal oxide composite. 
     Also, the pores of the metal oxide composite may have an average diameter of 10 nm to 800 nm. 
     Also, the quantum dots impregnated in the pores of the metal oxide composite may have a portion of 0.5 weight % to 65 weight % with respect to 100 weight % of a total matrix. 
     Also, the quantum dot composition may be formed by preparing a metal oxide composite with pores formed in the surface, coating the quantum dots, impregnating the coated quantum dots in the pores of the metal oxide composite, and coating the metal oxide composite. 
     Another aspect of the present disclosure provides a method of forming a quantum dot composition, including: preparing a metal oxide composite with pores formed in the surface; coating quantum dots; impregnating the coated quantum dots in the pores of the metal oxide composite; and coating the metal oxide composite. 
     Also, the preparing of the metal oxide composite with the pores formed in the surface may include preparing a metal oxide composite having a size of a Mie scattering range with respect to blue light. 
     Also, the preparing of the metal oxide composite with the pores formed in the surface may include preparing a metal oxide composite having an average diameter of 100 nm to 1000 nm. 
     Also, the preparing of the metal oxide composite with the pores formed in the surface may include preparing a metal oxide composite made of at least one metal oxide selected from among a metal oxide group including titanium oxide (TiO 2 ), aluminum oxide (Al 2 O 3 ), zinc oxide (ZnO), silicon dioxide (SiO 2 ), chrome oxide (CrO), zirconium oxide (ZrO 2 ), iron oxide (Fe 3 O 4 ), calcium oxide (CaO), tungsten dioxide (WO 2 ), tellurium dioxide (TeO 2 ), magnesium oxide (MgO), tin oxide (SnO), titanium oxide (TiO), zinc oxide (Ag 2 O), cobalt oxide (CoO), nickel oxide (NiO), and aluminum oxide (AlO). 
     Also, the coating of the quantum dots may include providing the quantum dots in an organic solvent including polymers to form polymer coating films on surfaces of the quantum dots. 
     Also, the impregnating of the coated quantum dots in the pores of the metal oxide composite may include adding the coated quantum dots and the metal oxide composite in a pre-prepared solvent and stirring the solvent. 
     Also, the method may further include drying the solvent to collect the metal oxide composite in which the quantum dots are impregnated. 
     Also, the coating of the metal oxide composite may include: forming an organic coating film on a surface of oxide powder; and forming an inorganic coating film on the surface of the oxide powder on which the organic coating film is formed. 
     Another aspect of the present disclosure provides a display apparatus to which the quantum dot composition is applied. 
     Also, the display apparatus may include: a backlight unit, wherein the quantum dot composition is applied to a light guide plate pattern of the backlight unit. 
     Also, the display apparatus may include a sheet on which the quantum dot composition is coated. 
     Advantageous Effects 
     The quantum dot composition, the preparation method thereof, and the device using the quantum dot composition, according to an aspect, can expect the following effects. 
     First, by using a quantum dot composition of a random raising structure with a maximized barrier property, it may be possible to improve the efficiency of the device, while reducing the quantity of used quantum dots. 
     Further, since no barrier film is used, an effect of cost reduction can be obtained. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  is a SEM image of a sheet type aluminum oxide (Al 2 O 3 ) composition having nano-sized pores. 
         FIG. 2  is a SEM image obtained after the aluminum oxide (Al 2 O 3 ) composition of  FIG. 1  is ball milled to sizes of several hundreds of nanometers to several micrometers. 
         FIG. 3  is a flowchart illustrating a process of preparing a quantum dot composition according to an embodiment. 
         FIG. 4  is a schematic view showing a flow of a process of preparing a quantum dot composition according to an embodiment. 
         FIG. 5  shows a configuration of a display apparatus according to an embodiment. 
         FIG. 6  shows optical wavelength conversion experiment results of blue light. 
     
    
    
     MODES OF THE INVENTION 
     Like reference numerals will refer to like components throughout this specification. This specification does not describe all components of the embodiments, and general information in the technical field to which the present disclosure belongs or overlapping information between the embodiments will not be described. 
     Also, it will be understood that when a certain part “includes” a certain component, the part does not exclude another component but can further include another component, unless the context clearly dictates otherwise. 
     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. 
     Reference numerals used in operations are provided for convenience of description, without describing the order of the operations, and the operations can be executed in a different order from the stated order unless a specific order is definitely specified in the context. 
     Hereinafter, the embodiments of the present disclosure will be described with reference to the accompanying drawings. 
     A quantum dot composition according to the present disclosure may include a metal oxide composite, wherein quantum dots are impregnated in pores formed in a surface of the metal oxide composite. 
     The metal oxide composite may be provided in the form of a random raising nano-micro composite. Hereinafter, in the present specification, a nano-micro composite means a composite with a nano- or micro-scale diameter, and the term “composite” may mean a nano-micro composition unless the context clearly dictates otherwise. 
     The metal oxide composite may have a diameter of 100 nm to 1000 nm. The diameter of the metal oxide may be calculated based on Mie scattering theory, and the diameter of the metal oxide may be calculated as a diameter of a Mie scattering range with respect to blue light. 
     Mie scattering, which is a theory about the scattering property of light when the wavelength of light is similar to the size of particles causing scattering, is that light is scattered to a degree similar to that of particles causing scattering when the wavelength of the light is similar to the size of the particles. 
     In the present disclosure, a metal oxide composite having a λ/4 to 2λ times diameter with respect to blue light having a wavelength range of about 400 nm to about 500 nm may be used to prepare a quantum dot composition. The present disclosure may provide a quantum dot composition by using the metal oxide composite having the diameter, thereby providing a display apparatus with improved optical efficiency. 
     In the surface of the metal oxide composite, nano-sized pores may be formed. The pores of the metal oxide composite may have an average diameter of 10 nm to 800 nm. Also, the pores of the metal oxide composite may have a volume ratio of 5 to 65 with respect to a total volume of the metal oxide composite. Therefore, the quantum dots impregnated in the pores of the metal oxide composite may have a portion of 0.5 weight % to 65 weight % with respect to 100 weight % of a total matrix. 
     In the pores of the metal oxide composite, the quantum dots may be impregnated. However, when the sizes of the pores are excessively large or when a ratio of the volume of the pores with respect to the total volume of the metal oxide composite is high, intervals between the quantum dots impregnated in the pores of the metal oxide composite may become narrow, which may make the performance expression of the quantum dots difficult. Meanwhile, when the sizes of the pores are excessively small or when a ratio of the volume of the pores with respect to the total volume of the metal oxide composite is low, an absolute quantity of quantum dots that can be impregnated in the pores of the metal oxide composite may be reduced, which may also make the performance expression of the quantum dots difficult. Therefore, it may be necessary to appropriately adjust the sizes of pores formed in the surface of the metal oxide composite and a ratio of the volume of pores with respect to the total volume of the metal oxide composite. 
     The metal oxide may be at least one selected from among a metal oxide group including titanium oxide (TiO 2 ), aluminum oxide (Al 2 O 3 ), zinc oxide (ZnO), silicon dioxide (SiO 2 ), chrome oxide (CrO), zirconium oxide (ZrO 2 ), iron oxide (Fe 3 O 4 ), calcium oxide (CaO), tungsten dioxide (WO 2 ), tellurium dioxide (TeO 2 ), magnesium oxide (MgO), tin oxide (SnO), titanium oxide (TiO), zinc oxide (Ag 2 O), cobalt oxide (CoO), nickel oxide (NiO), and aluminum oxide (AlO), although not limited to the above-mentioned examples. 
     The metal oxide composite may be prepared by ball milling a sheet type metal oxide composite to sizes of several hundreds of nanometers to several micrometers. 
       FIGS. 1 and 2  are SEM images obtained after a sheet type aluminum oxide (Al 2 O 3 ) composite having nano-sized pores is ball milled to sizes of several hundreds of nanometers to several micrometers. 
     In detail,  FIG. 1  is an image of the surface of a sheet type aluminum oxide composite. It can be seen from  FIG. 1  that a large number of nano-sized pores are formed in the surface of the aluminum oxide composite.  FIG. 2  is an image of a sheet type aluminum oxide (Al 2 O 3 ) composite after the aluminum oxide composite is ball milled to sizes of several hundreds of nanometers to several micrometers, wherein the surface of the ball-milled aluminum oxide composite includes a large number of nano-sized pores. A method of preparing the metal oxide composite, according to the present disclosure, is not limited to the ball milling method, and various modifications may be possible within a technical scope that can be easily conducted by one of ordinary skill in the art. 
     In the insides of the pores of the metal oxide composite, quantum dots may be provided. Polymer coating films may be formed on the surfaces of the quantum dots. For example, the quantum dots may be coated by mixing polymers as a main ingredient of coating films in an organic solvent allowing quantum dot dispersion to prepare a polymer organic solvent and mixing quantum dots in the polymer organic solvent. 
     The organic solvent may be a solvent, such as toluene, hexane, chloroform, n-octane, or the like, and the polymers may be PMMA-co-MMA, PS-b-P(S-r-4HS), P(S-r-4VR)-b-PMMA, PS-b-PFS, poly(vinylsilazane)-block-polystyrene, polynorbornene-block-polynorbornenedecaborane), or the like. However, examples of a usable organic solvent and polymers are not limited to the above-mentioned materials. 
     The present disclosure may improve durability of particles against light and water by accommodating quantum dots with polymer coating films in the insides of pores of a metal oxide composite. Also, in a process of coating oxide powder, which will be described later, an acidic solvent may be generally used, and the quantum dots may be protected by coating films formed on the surfaces of the quantum dots during the coating process. 
     So far, the ingredients of the quantum dot composition have been described. Hereinafter, for easy understanding, a method of preparing the quantum dot composition will be described in more detail. 
       FIG. 3  is a flowchart illustrating a process of preparing a quantum dot composition according to an embodiment, and  FIG. 4  is a schematic view showing a flow of a process of preparing a quantum dot composition according to an embodiment. 
     As shown in  FIGS. 3 and 4 , a process of preparing a quantum dot composition according to an embodiment may include: operation 10 of preparing a metal oxide composite MO with pores H formed in the surface; operation 15 of coating quantum dots QD; operation 20 of impregnating the coated quantum dots QD into the pores H of the metal oxide composite MO; and operation  25  of coating the metal oxide composite MO. 
     First, operation 10 of preparing the metal oxide composite MO may be performed. The metal oxide composite MO may be provided in the form of a random raising nano-micro composition. For this, the metal oxide composite MO may have a diameter of 100 nm to 1000 nm. The diameter of the metal oxide may be calculated based on the Mie scattering theory, and calculated as a diameter of a Mie scattering range with respect to blue light. Hereinafter, overlapping descriptions thereof will be omitted. 
     Operation 10 of preparing the metal oxide composite MO may include operation of preparing a metal oxide composite MO made of at least one metal oxide selected from among a metal oxide group including titanium oxide (TiO 2 ), aluminum oxide (Al 2 O 3 ), zinc oxide (ZnO), silicon dioxide (SiO 2 ), chrome oxide (CrO), zirconium oxide (ZrO 2 ), iron oxide (Fe 3 O 4 ), calcium oxide (CaO), tungsten dioxide (WO 2 ), tellurium dioxide (TeO 2 ), magnesium oxide (MgO), tin oxide (SnO), titanium oxide (TiO), zinc oxide (Ag 2 O), cobalt oxide (CoO), nickel oxide (NiO), and aluminum oxide (AlO). However, examples of usable metal oxide are not limited to the above-mentioned materials. 
     Then, operation 15 of coating quantum dots QD will be performed. Operation 15 of coating quantum dots QD may include operation of providing quantum dots QD in an organic solvent including polymers to form polymer coating films PL on the surfaces of the quantum dots QD. More specifically, by mixing polymers as a main ingredient of coating films PL in an organic solvent allowing quantum dot dispersion to prepare a polymer organic solvent and providing quantum dots QD in the polymer organic solvent, polymer coating films PL may be formed on the surfaces of the quantum dots QD. 
     The organic solvent may be a solvent, such as toluene, hexane, chloroform, n-octane, or the like, and the polymers may be PMMA-co-MMA, PS-b-P(S-r-4HS), P(S-r-4VP)-b-PMMA, PS -b-PFS, poly(vinylsilazane)-block-polystyrene, polynorbornene-block-polynorbornenedecaborane, or the like. However, examples of a usable organic solvent and polymers are not limited to the above-mentioned materials. 
     Then, operation 20 of impregnating the coated quantum dots QD in the pores H of the metal oxide composite MO may be performed. Operation 20 may be performed by adding the coated quantum dots QD and the metal oxide composite MO in a solvent prepared in advance and then stirring the solvent. After the stirring is completed, the solvent may be dried to collect a metal oxide composite MO in which the quantum dots QD are impregnated. In the current embodiment, the metal oxide composite MO may be collected in the form of powder. 
     Thereafter, operation  25  of coating the metal oxide composite MO may be performed. 
     Operation  25  of coating the metal oxide composite MO may include operation  27  of forming an organic coating film OL on the metal oxide composite MO and operation  29  of forming an inorganic coating film IOL on the surface of the metal oxide composite MO on which the organic coating film OL is formed. 
     For example, operation  27  of forming the organic coating film OL on the surface of the metal oxide composite MO may include operation of mixing polymers as a main ingredient of a coating film OL in an organic solvent to prepare a polymer organic solvent, and providing the metal oxide composite MO in the polymer organic solvent. In the current embodiment, polymers such as PS-PE0 block copolymers may be used. However, examples of usable polymers are not limited to this. 
     Successively, operation of again dispersing the metal oxide composite MO with the organic coating film OL formed on the surface in the solvent, and reacting silica precursors with the solvent to form an inorganic coating film IOL on the surface of the metal oxide composite MO may be performed. 
     In the above-described embodiment, a case of forming both the organic coating film OL and the inorganic coating film IOL has been described as an example. However, a method of coating the metal oxide composite MO is not limited to the above-described example. For example, one of the organic coating film OL and the inorganic coating film IOL may be formed, and according to some embodiments, a plurality of organic coating films or a plurality of inorganic coating films may be formed. 
     After operation of forming the coating film on the surface of the metal oxide composite MO is completed, the metal oxide composite MO with the coating film may be dispersed in a solvent to acquire a quantum dot composition in a colloid form (operation  30 ). 
     So far, the embodiments of the quantum dot composition and the method of preparing the quantum dot composition have been described. The quantum dot composition prepared by the above-described method may be applied to a display apparatus. More specifically, the quantum dot composition may be used as pattern ink for forming a pattern on a light guide plate of a backlight unit of a display apparatus, and may be coated on a reflector member of the display apparatus. Also, the quantum dot composition may be applied to a quantum dot filter disposed on the front surface of a light emitting module of an edge type display, in such a way to be applied on an optical lens of the light emitting module. 
     Hereinafter, for easy understanding, a method of applying the quantum dot composition according to the present disclosure to a display apparatus will be described in detail. 
       FIG. 5  shows a configuration of a display apparatus according to an embodiment. 
     As shown in  FIG. 5 , a display apparatus  10  according to an embodiment may include a backlight unit  100  and a display  200 . However, the technical concept of the present disclosure is not limited to the display apparatus  10  shown in  FIG. 5 , and some components of the display apparatus  10  may be omitted as necessary. 
     The backlight unit  100  may include a light guide plate  110 , a light emitting module  120  disposed along one side of the light guide plate  110  and configured to emit light, a quantum dot filter  130  disposed between the light emitting module  120  and the one side of the light guide plate  110 , a reflector member  140  disposed below the light guide plate  110 , and at least one optical sheet  150  disposed on the light guide plate  110 . 
     Also, the backlight unit  100  may include a lower cover  160  for accommodating the light guide plate  110 , the light emitting module  120 , the quantum dot filter  130 , and the reflector member  140 . Also, the backlight unit  100  may include a heat radiation member  170  coupled with the quantum dot filter  130 . 
     The light guide plate  110  may diffuse incident light to transform it to surface light. When light emitted from the light emitting module  120  is incident to the light guide plate  110 , the light guide plate  110  may diffuse the light through total reflection, etc. to transform it to surface light. The light diffused by the light guide plate  110  may be irradiated toward the display  200 . 
     The light guide plate  110  may be made of a transparent material. For example, the light guide plate  110  may include one among acrylic resin such as polymethyl metaacrylate (PMMA), polyethylene terephthalate (PET) resin, poly carbonate (PC) resin, cycloolefin copolymer (COC) resin, and polyethylene naphthalate (PEN) resin. 
     The light emitting module  120  may be coupled with at least one side of the light guide plate  110 . 
     The light emitting module  120  may include a board  121 , and a plurality of light-emitting device packages  122  arranged at regular intervals on the board  121 . 
     The board  121  may include a printed circuit board (PCB) including a circuit pattern for supplying an electrical signal to the light-emitting device packages  122 . 
     The light-emitting device packages  122  may be electrically connected to the circuit pattern formed on the board  121 , and operate as a light source of the display apparatus  10 . That is, the light-emitting device packages  122  may receive an electrical signal from the circuit pattern of the board  121 , convert the electrical signal into an optical signal, and output the optical signal. 
     Each light-emitting device package  122  may include a light-emitting diode operating as a point light source. 
     The light-emitting device packages  122  may be positioned on one side of the lower cover  160  or on a heat radiation plate (not shown). In this case, the board  121  for supporting the light-emitting device packages  122  may be omitted. 
     The quantum dot filter  130 , which is a light wavelength converting member, may be positioned between the light-emitting module  120  and the light guide plate  110 . The quantum dot filter  130  may be a filter to which the quantum dot composition according to the present disclosure is applied. The quantum dot filter  130  may convert the wavelength of light emitted from the light-emitting module  120  through the Quantum Dot Effect, and emit the light with the converted wavelength to the light guide plate  110 . For example, when blue light is irradiated from the light emitting module  120 , the quantum dot filter may convert the wavelength of the blue light to emit white light. 
     Quantum dots generate strong fluorescence in a narrow wavelength band. More specifically, the quantum dots generate light when electrons that have been in a valence band (an unstable (excited) state) fall to a conduction band. The generated fluorescence generates light of a shorter wavelength at smaller particles of the quantum dots, and light of a longer wavelength at larger particles of the quantum dots. 
     Accordingly, by adjusting the sizes of quantum dots, various wavelengths of light, such as red, green, and blue, may be easily obtained. Since quantum dots have excellent luminescent properties, white light implemented by using quantum dots may provide higher color reproduction of green and red than that implemented by typical white light emitting diodes. 
     The quantum dot filter  130  may include quantum dots of different sizes according to the kinds of light emitted from the light source and light that is to be converted through the quantum dots. More specifically, quantum dots that are accommodated in the pores of the metal composite in the quantum dot composition may have various sizes according to the kind of light that is to be converted through the quantum dots. 
     When a light emitting device of emitting blue light is used as a light source and white light needs to be emitted through the quantum dot filter  130 , the quantum dot filter  130  to which a quantum dot composition according to the following example is applied may be used. 
     More specifically, the metal oxide composite of the quantum dot composition may accommodate quantum dots of absorbing light of a blue wavelength band to emit light of a green wavelength band and quantum dots for absorbing light of the blue wavelength band to emit light of a red wavelength band, randomly, in the pores. 
     Accordingly, when blue light emitted from the light source passes through the quantum dot filter, the quantum dots may absorb the blue light to convert it to light of a green or red wavelength band, and as a result, light of a blue wavelength, light of a green wavelength, and light of a red wavelength may be mixed to emit white light. 
     Also, since the metal oxide composite is provided in the form of a random raising nano-micro composite, diffused reflection of light may be induced to efficiently improve the quantity of used quantum dots. 
     Below the light guide plate  110 , the reflector member  140  may be positioned. 
     The reflector member  140  may reflect light incident from the bottom of the light guide plate  110  to direct the light to the light guide plate  110 , thereby improving the brightness of the backlight unit  100 . The reflector member  140  may be made of a material, such as polyethylene terephthalate (PET), poly carbonate (PC), and poly vinyl chloride (PVC), although not limited thereto. 
     On the light guide plate  110 , at least one optical sheet  150  having light transmission may be positioned. The optical sheet  150  may be used to improve the optical properties of light transferred from the light guide plate  110 . 
     The optical sheet  150  may include a diffuser sheet  151 , a prism sheet  152 , and a protective sheet  153 . 
     The diffuser sheet  151  may diffuse light incident from the light emitting module  120  such that the light is uniformly distributed over a wide range, and irradiate the diffused light to the display panel  210 . 
     The prism sheet  152  may perform a function of deflecting obliquely incident light among light incident to the prism sheet  152  to cause the light to exit perpendicularly. At least two prism sheets  152  may be positioned between the display panel  210  and the diffuser sheet  151  to deflect the direction of light exiting the diffuser sheet  151  to a perpendicular direction. 
     The protective sheet  152  may protect the lower plates against contamination such as water. Also, the protective sheet  153  may prevent the Moire effect, and widen a viewing angle. 
     Below the reflective member  140 , the lower cover  160  may be positioned. 
     The lower cover  160  may be made of a metal, etc., and formed in the shape of a box whose upper part opens. For example, the lower cover  160  may be formed by bending or curving a metal plate or the like. 
     In an inside space of the lower cover  160  formed by bending or curving, the light emitting module  120 , the light guide plate  110 , the quantum dot filter  130 , and the reflector member  140  may be accommodated. Also, the lower cover  160  may support the optical sheet  150  and the display  200 . 
     The display  200  may include a display panel  210  and a driving circuit portion  220 . Also, the display  200  may further include a panel guide  230  for supporting the display panel  210 , and an upper case  240  surrounding the edges of the display panel  210  and coupled with the panel guide  230 . 
     One side of the display panel  210  may be connected to the driving circuit portion  220 . The driving circuit portion  220  may include a printed circuit board  221  for supplying scan signals to the gate lines of a thin film transistor substrate, and a printed circuit board  222  for supplying data signals to the data lines. 
     Meanwhile, the display apparatus  10  to which the quantum dot filter  130  is applied may have excellent color reproducibility, whereas the display apparatus  10  may have a problem that the quantum dot filter  130  deteriorates due to high temperature. Accordingly, when the quantum dot filter  130  including quantum dots is positioned adjacent to the light-emitting module  120  in the backlight unit  100 , the life cycle of the quantum dot filter  130  may be shortened. 
     According to the embodiments of the present disclosure, at least one heat radiation member  170  may be further provided to improve the deterioration of the quantum dot filter  120  due to high temperature. For example, as shown in  FIG. 3 , heat radiation members  171  and  172  may be respectively installed above and below the quantum dot filter  130 . The heat radiation member  170  may protect the quantum dot filter  130  against heat emitted from the light-emitting module  120 . 
     In  FIG. 6 , a case in which the quantum dot composition according to the present disclosure is applied to a quantum dot filter of an edge type display is shown as an example. However, the technical concept of the present disclosure is not limited to the above-described example, and the quantum dot composition according to the present disclosure may be applied in another form. 
     The quantum dot composition may be applied as pattern ink for forming the pattern of the light guide plate  110 , or as coating ink for coating one surface of the reflector member  140 . Also, as described above, the quantum dot composition may be applied on the optical lens provided around the light emitting device packages  122  of the light emitting module  120 . 
     So far, an example of a display apparatus to which the quantum dot composition according to the present disclosure is applied has been described. 
     Now, for easy understanding, illumination experiment results for quantum dots to which the random raising barrier according to the present disclosure is applied and quantum dots to which the random raising barrier according to the present disclosure is not applied will be described. 
     In Experiment Example 1, a test piece was prepared by impregnating quantum dots in the pores of a metal oxide composite having a diameter of 1000 μm or less, adding a binder, and then hardening the binder. Then, blue light was irradiated on the test piece. 
     In Comparative Example 1, a test piece was prepared by impregnating quantum dots in the pores of a metal oxide composite having a diameter of 40μm to 63 μm, adding a binder, and then hardening the binder. Then, blue light was irradiated on the test piece. 
     Optical wavelength experiment results of blue light are shown in Table 1, below. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 1 
               
             
            
               
                   
                   
               
               
                   
                 CIE 
                   
               
            
           
           
               
               
               
               
               
            
               
                   
                 Condition 
                 Cx 
                 Cy 
                 Lumen (lm) 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                   
                 Experiment 
                 0.156 
                 0.022 
                 58.2 
               
               
                   
                 Example 1 
               
               
                   
                 Comparative 
                 0.241 
                 0.068 
                 45.0 
               
               
                   
                 Example 1 
               
               
                   
                 Blue Light 
                 0.422 
                 0.165 
                 33.5 
               
               
                   
                   
               
            
           
         
       
     
     As seen from Table 1, it is confirmed that in Experiment Example 1, lumen corresponding to luminous flux is improved by about 1.8 times compared to Comparative Example 1. 
     Also, it is confirmed that in Experiment Example 1 in which a metal oxide composite of 1000 μm or less is used, blue light is more stably converted to red light compared to Comparative Example 1, and as a result, light efficiency is improved. 
     While the present disclosure has been particularly described with reference to exemplary embodiments, it should be understood by those of skilled in the art that various changes in form and details may be made without departing from the spirit and scope of the present disclosure.