Abstract:
The present invention relates to a substrate for the color conversion of a light-emitting diode and a manufacturing method therefor and, more specifically, to a substrate for the color conversion of a light-emitting diode and a manufacturing method therefor, which enable a quantum dot (QD) and a structure, in which the QD is supported, to have a color conversion function for implementing white light. To this end, the present invention provides a substrate for the color conversion of a light-emitting diode, comprising: a first glass substrate arranged on a light-emitting diode; a second glass substrate formed to face the first glass substrate; a structure arranged between the first glass substrate and the second glass substrate, having a hollow portion and formed from a mixture of a yellow phosphor and a low-melting point frit glass; a QD filling the hollow portion; and sealing materials respectively formed between the first glass substrate and the lower side of the structure and between the second glass substrate and the upper side of the structure.

Description:
BACKGROUND 
       [0001]    Field 
         [0002]    The present disclosure generally relates to a color conversion substrate for a light-emitting diode (LED) and a method of fabricating the same. More particularly, the present disclosure relates to a color conversion substrate for an LED, in which not only a quantum dot (QD) but also a structural body containing the QD has a color conversion function for producing white light, and a method of fabricating the same. 
         [0003]    Description of Related Art 
         [0004]    A light-emitting diode (LED) is a semiconductor device formed of a compound such as gallium arsenide (GaAs) to emit light when an electrical current is applied thereto. The LED uses a p-n junction semiconductor structure into which minority carriers, such as electrons or holes, are injected, such that light is generated by the recombination of electrons and holes. 
         [0005]    The characteristics of LEDs include low power consumption, a relatively long lifespan, the ability to be mounted in cramped spaces, and strong resistance to vibrations. LEDs are commonly used in display devices and in the backlight units of display devices. Recently, research into applying LEDs to general illumination devices has been undertaken. In addition to monochromatic LEDs, such as red, blue, or green LEDs, white LEDs have also come onto the market. In particular, a sharp increase in demand for white LEDs is anticipated, in line with the application of white LEDs to vehicle lighting devices and general lighting devices. 
         [0006]    In the field of LED technology, white light is commonly generated using two main methods. The first method to generate white light includes disposing monochromatic LEDs, such as red, green, and blue LEDs, adjacently to each other such that various colors of light emitted by the monochromatic LEDs are mixed. However, color tones may change depending on the environment in which such devices are used, since individual monochromatic LEDs have different thermal or temporal characteristics. In particular, color stains may occur, making it difficult to uniformly mix different colors of light. The second method to generate white light includes applying a fluorescent material to an LED and mixing a portion of initial light emitted by the LED and secondary light of which wavelength has been converted by the fluorescent material. For example, a fluorescent material generating yellowish-green or yellow light may be used as a light excitation source on a blue LED, whereby white light can be produced by mixing blue light emitted by the blue LED and yellowish-green or yellow light excited by the fluorescent material. At present, the second method of realizing white light utilizing a blue LED and a fluorescent material is generally used. 
         [0007]    Recently, quantum dots (QDs) have been used for color conversion to produce white light. QDs generate relatively strong light within a narrow wavelength, the light being stronger than light generated from a typical fluorescent material. In general, a QD-LED backlight unit generates white light by irradiating yellow QDs with blue light emitted by a blue LED, and applies the white light to a liquid crystal display (LCD) as backlight. LCDs using such a QD-LED backlight unit have high potential as new displays, since the characteristics of such LCDs include superior color reproduction unlike those using a traditional backlight using LEDs only, the ability to realize full color comparable to that of organic light emitting diodes (OLEDs), as well as lower fabrication costs and higher manufacturing productivity than OLED TVs. 
         [0008]    In the related art, a method of fabricating such a QD-LED includes: forming a QD sheet by mixing QDs and a polymer; and subsequently coating the QD sheet with a plurality of barrier layers in order to protect the sheet surface from external moisture or the like and to maintain the lifespan of the LED. However, this related-art method is problematic in that fabrication costs are relatively high, due to the barrier layers needing to be applied several times, and most of all, this method fails to entirely protect the QDs from the external environment. 
         [0009]    In addition, another method used in the related art includes: etching a glass surface to a certain depth; inserting QDs into the etched portions of the glass surface; covering the resultant structure with a glass cover; applying low melting point glass to the periphery of the glass cover; firing the applied low melting point glass; and sealing the resultant structure using a laser beam. However, the etching process may cause fabrication costs to be increased. In particular, it may be difficult to use a thin glass plate. 
         [0010]    In the meantime, since QDs have a short lifespan, when a QD-LED is used for a long period of time, the luminance thereof is reduced due to degradation of QDs. The use of QDs consequently leads to a problem in that it may be difficult to obtain or ensure the lifespan of an LCD using a QD-LED backlight. 
       RELATED ART DOCUMENT 
       [0011]    Patent Document 1: Korean Patent Application Publication No. 10-2012-0009315 (Feb. 1, 2012) 
       BRIEF SUMMARY 
       [0012]    Various aspects of the present disclosure provide a color conversion substrate for a light-emitting diode (LED), in which not only a quantum dot (QD) but also a structural body containing the QD has a color conversion function for producing white light, and a method of fabricating the same. 
         [0013]    According to an aspect, a color conversion substrate includes: a first glass substrate disposed over an LED; a second glass substrate facing the first glass substrate; a structural body disposed between the first glass substrate and the second glass substrate, having a hollow portion, and formed of a mixture of a yellow fluorescent material and a low melting point glass frit; a QD accommodated in the hollow portion of the structural body; and a sealant disposed between the first glass substrate and a bottom surface of the structural body and between the second glass substrate and a top surface of the structural body. 
         [0014]    The yellow fluorescent material may be implemented as a yttrium aluminum garnet (YAG)-based fluorescent material. 
         [0015]    The softening point of the low melting point glass frit may be 650° C. or below. 
         [0016]    The refractive index of the low melting point glass frit may be 1.7 or greater. 
         [0017]    The sealant may be formed of a low melting point glass frit. 
         [0018]    A plurality of the structural bodies may be disposed between the first glass substrate and the second glass substrate. 
         [0019]    According to another aspect, a method of fabricating a color conversion substrate includes: forming a structural body having a hollow portion and formed of a mixture of a yellow fluorescent material and a low melting point glass frit; disposing the structural body on a first glass substrate; disposing a QD within the hollow portion of the structural body disposed on the first glass substrate; disposing a second glass substrate on the structural body such that the second glass substrate faces the first glass substrate; and sealing a resultant structure by bonding the first glass substrate, the structural body, and the second glass substrate. 
         [0020]    The operation of forming the structural body may include: preparing granules by mixing the yellow fluorescent material and powder of the low melting point glass frit; and shaping and sintering the granules into a shape of an rectangular frame. 
         [0021]    The operation of disposing the structural body may include fixing the structural body on the first glass substrate by means of a first sealant formed of a low melting point glass frit. 
         [0022]    The operation of disposing the second glass substrate may include fixing the second glass substrate on the structural body by means of a second sealant formed of a low melting point glass frit. 
         [0023]    The operation of sealing the resultant structure may include bonding the first glass substrate and the structural body to each other and the second glass substrate and the structural body to each other by irradiating the first sealant and the second sealant with laser beams. 
         [0024]    According to further another aspect, a method of fabricating a color conversion substrate includes: preparing a paste by mixing a yellow fluorescent material and a low melting point glass frit; forming a structural body having a hollow portion by printing the paste on a first glass substrate; disposing a QD within the hollow portion of the structural body disposed on the first glass substrate; disposing a second glass substrate on the structural body such that the second glass substrate faces the first glass substrate; and sealing a resultant structure by bonding the structural body and the second glass substrate. 
         [0025]    The operation of disposing the second glass substrate may include fixing the second glass substrate on the structural body by means of a sealant formed of a low melting point glass frit. 
         [0026]    The operation of sealing the resultant structure may include bonding the structural body and the second glass substrate by irradiating the sealant with laser beams. 
         [0027]    The yellow fluorescent material may be implemented as a YAG-based fluorescent material. 
         [0028]    The low melting point glass frit may have a softening point of 650° C. or below and a refractive index of 1.7 or greater. 
         [0029]    According to the present disclosure as set forth above, since the structural body in which the QD is accommodated contains the yellow fluorescent material, not only the QD but also the structural body in which the QD is accommodated can have a color conversion function for producing white light. It is therefore possible to increase or compensate for the lifespan of an LED and the lifespan of a display device using the same in a backlight unit thereof, in which the lifespan would otherwise be reduced due to degradation in the QD. 
         [0030]    In addition, according to the present disclosure, since the structural body in which the QD is accommodated is formed of a yellow fluorescent material and a low melting point glass frit, the refractive index of which is similar to the refractive index of the yellow fluorescent material, the luminous efficiency of the LED can be improved. 
         [0031]    Furthermore, according to the present disclosure, since the structural body is bonded to the overlying and underlying substrates by means of the sealant formed of a low melting point glass frit, it is possible to provide a hermetic seal to the LED color conversion substrate, the fabrication of which is completed after the bonding by means of the sealant, whereby the QD accommodated within the color conversion substrate can be excellently protected from the external environment. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0032]      FIG. 1  is a plan view illustrating a color conversion substrate for an LED according to an exemplary embodiment; 
           [0033]      FIG. 2  is a cross-sectional view taken along line A-A in  FIG. 1 ; 
           [0034]      FIG. 3  is a plan view illustrating a color conversion substrate for an LED according to another exemplary embodiment; 
           [0035]      FIG. 4  is a cross-sectional view taken along line B-B in  FIG. 3 ; 
           [0036]      FIG. 5  is a process flowchart illustrating a method of fabricating a color conversion substrate for an LED according to an exemplary embodiment; 
           [0037]      FIG. 6  to  FIG. 9  are process views sequentially illustrating the operations of the method of fabricating a color conversion substrate for an LED according to the exemplary embodiment; 
           [0038]      FIG. 10  is a process flowchart illustrating a method of fabricating a color conversion substrate for an LED according to another exemplary embodiment; and 
           [0039]      FIG. 11  to  FIG. 13  are process views sequentially illustrating the operations of the method of fabricating a color conversion substrate for an LED according to the another exemplary embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0040]    Reference will now be made in detail to a color conversion substrate for a light-emitting diode (LED) and a method of fabricating the same according to the present disclosure, embodiments of which are illustrated in the accompanying drawings and described below, so that a person skilled in the art to which the present disclosure relates could easily put the present disclosure into practice. 
         [0041]    Throughout this document, reference should be made to the drawings, in which the same reference numerals and symbols will be used throughout the different drawings to designate the same or like components. In the following description, detailed descriptions of known functions and components incorporated herein will be omitted in the case that the subject matter of the present disclosure is rendered unclear by the inclusion thereof. 
         [0042]    As illustrated in  FIG. 1  and  FIG. 2 , the LED color conversion substrate  100  according to the present embodiment is a substrate disposed over an LED, encapsulating the LED, and converting the color (wavelength) of a portion of light emitted by the LED. Consequently, an LED package including the LED color conversion substrate  100  and, for example, a blue LED radiates white light by mixing blue light emitted by the blue LED and color-converted light excited by the LED color conversion substrate  100 . Although not illustrated in the drawings, the LED may include an LED body and an LED chip. The LED body is a structure having a hollow portion in a predetermined shape, providing a structural space for accommodation of the LED chip. The LED body has wires and a lead frame by which the LED chip is electrically connected to an external power source. The LED chip is a light source emitting light when an electrical current is applied thereto from the external power source, is mounted on the LED body, and is connected to the external power source via the wires and the lead frame. The LED chip is implemented as a forward junction of an n-semiconductor layer that provides electrons and a p-semiconductor layer that provides holes. 
         [0043]    The LED color conversion substrate  100  according to the present embodiment disposed over an LED as above includes a first glass substrate  110 , a second glass substrate  120 , a structural body  130 , a quantum dot (QD)  140 , and a sealant  150 . 
         [0044]    The first glass substrate  110  is the portion of the LED color conversion substrate  100  disposed adjacently to the LED. The second glass substrate  120  is disposed to face the first glass substrate  110 , forming the portion of the LED color conversion substrate  100  positioned farthest from the LED. That is, the first glass substrate  110  and the second glass substrate  120  are spaced apart from each other by means of the structural body  130 , the QD  140 , and the sealant  150  sandwiched therebetween, such that the first glass substrate  110  and the second glass substrate  120  face each other. The first glass substrate  110  and the second glass substrate  120  act as paths by which light emitted by the LED is externally radiated while protecting the QD  140  accommodated in the structural body  130  from the external environment. For this, transparent glass substrates may be used as the first glass substrate  110  and the second glass substrate  120 . According to an exemplary embodiment, the first glass substrate  110  and the second glass substrate  120  may be formed of borosilicate glass or soda lime glass. 
         [0045]    The structural body  130  is disposed between the first glass substrate  110  and the second glass substrate  120 . The structural body  130  has a hollow portion in the central portion thereof in which the QD  140  is accommodated. As illustrated in  FIG. 1  and  FIG. 2 , the structural body  130  is substantially shaped as an rectangular frame. According to an exemplary embodiment, the structural body  130  may be formed of a mixture of a yellow fluorescent material and a low melting point glass frit. The yellow fluorescent material may be a yttrium aluminum garnet (YAG)-based fluorescent material. 
         [0046]    When the structural body  130  contains the yellow fluorescent material, not only the QD  140  but also the structural body  130  in which the QD  140  is accommodated can have a color conversion function for producing white light. When the QD  140  has degraded along with the LED being used for a long period of time, the structural body  130  can consequently compensate for the color conversion function of the QD  140 , thereby increasing or compensating for the lifespan of the LED and the lifespan of a display device using the same in a backlight unit thereof. 
         [0047]    The low melting point glass frit that forms the structural body  130  together with the yellow fluorescent material may be formed of Bi 2 O 3 —ZnO—B 2 O 3 -based glass frit that has a softening point of 650° C. or below and a refractive index of 1.7 or greater. When the low melting point glass frit having a softening point higher than 650° C. is bonded to the first glass substrate  110  and the second glass substrate  120 , the first glass substrate  110  and the second glass substrate  120  are susceptible to deformation, since the softening point of the low melting point glass frit is higher than the strain point of either the first glass substrate  110  or the second glass substrate  120 . In addition, the refractive index of the low melting point glass frit may be 1.7 or greater, which can similarly match the refractive index of the YAG-based yellow fluorescent material, thereby improving the luminous efficiency of the LED. When the refractive index of the low melting point glass frit does not match the refractive index of the yellow fluorescent material, it may be difficult to obtain a desirable degree of luminous efficiency due to the scattering of light. 
         [0048]    In addition, the structural body  130  according to the present embodiment includes a low melting point glass frit, the composition of which is the same as the composition of the low melting point glass frit of the sealant  150 , such that the structural body  130  can cooperate with the sealant  150  to form a hermetic seal through laser sealing. This can consequently provide an excellent degree of protection for the QD  140  accommodated within the structural body  130  from the external environment. 
         [0049]    The structural body  130  may be fabricated by powder compaction before being bonded to the first glass substrate  110 , or may be formed as a paste before being applied on the first glass substrate  110  through printing. These operations will be described in greater detail hereinafter in the method of fabricating a color conversion substrate. 
         [0050]    The QD  140  is accommodated within the hollow portion of the structural body  130 . The QD  140  is hermetically sealed by the first glass substrate  110 , the second glass substrate  120 , the structural body  130 , and the sealant  150 , whereby the QD  140  can be entirely protected from the external environment. The QD  140  is a semiconductor nano-crystal material, the diameter of which ranges from about 1 mn to about 10 nm, and that has a quantum confinement effect. The QD  140  converts the color (wavelength) of light emitted by the LED, thereby generating wavelength-converted light, or fluorescent light. According to the present embodiment, a blue LED may be used as the LED, and the QD  140  is formed of a QD material able to wavelength-convert a portion of light emitted by the blue LED to yellow light in order to produce white light by mixing the yellow light and the blue light. 
         [0051]    The sealant  150  is disposed between the first glass substrate  110  and the bottom surface of the structural body  130  and between the second glass substrate  120  and the top surface structural body  130 . With this configuration, due to a sealing process of irradiating the sealant  150  with a laser beam, the QD  140  can be hermetically sealed by the first glass substrate  110  and the structural body  130  and by the second glass substrate  120  and the structural body  130 , thereby being entirely protected from the external environment. According to the present embodiment, the sealant  150  may be formed of a glass frit, the coefficient of thermal expansion (CTE) of which is equal or similar to the CTE of either the first glass substrate  110 , the second glass substrate  120 , or the structural body  130 , such that the sealant  150  can be bonded thereto by laser sealing. In addition, it is preferable that the sealant  150  be formed of a glass frit, the softening point of which is lower than the softening point of either the first glass substrate  110  or the second glass substrate  120 , in order to prevent either the first glass substrate  110  or the second glass substrate  120  from being transformed while firing is being carried out to form the sealant  150  on either the first glass substrate  110  or the second glass substrate  120 . For example, the sealant  150  may be formed of a V 2 O 5 —P 2 O 5 -based glass frit or a Bi 2 O 3 —B 2 O 3 —ZnO-based glass frit that has superior ability to absorb laser light, the wavelength of which ranges from  800  nm to  900  nm. That is, the sealant  150  may be formed of a low melting point glass frit, the composition of which is identical to the composition of the low melting point glass frit of the structural body  130 . 
         [0052]    Hereinafter, an LED color conversion substrate according to another exemplary embodiment will be described with reference to  FIG. 3  and  FIG. 4 . 
         [0053]      FIG. 3  is a plan view illustrating the LED color conversion substrate according to the another embodiment, and  FIG. 4  is a cross-sectional view taken along line B-B in  FIG. 3 . 
         [0054]    As illustrated in  FIG. 3  and  FIG. 4 , the LED color conversion substrate  200  according to the another embodiment is configured such that a plurality of structural bodies  130  are disposed between a first substrate  110  and a second substrate  120  facing the first substrate  110 . The present embodiment differs from the former embodiment only in terms of the number of the structural bodies  130  and the resultant number of QDs  140 . Therefore, detailed descriptions of the components of the present embodiment will be omitted since they are identical to those of the former embodiment. 
         [0055]    The color conversion substrate  200  having this structure may be a substrate applicable to a plurality of LEDs used as a backlight source of a large display or a light source of a wide area lighting device, or may be a bulk substrate intended to be divided into cells, each of which is based on or defined by a single structural body  130 , and is applied to a single LED. 
         [0056]    Hereinafter, a method of fabricating an LED color conversion substrate according to an exemplary embodiment will be described with reference to  FIG. 5  to  FIG. 9 . 
         [0057]    As illustrated in  FIG. 5 , the method of fabricating an LED color conversion substrate according to the present embodiment includes structural body forming operation S 1 , structural body disposing operation S 2 , QD accommodating operation S 3 , second glass substrate disposing operation S 4 , and sealing operation S 5 . 
         [0058]    First, as illustrated in  FIG. 6 , the structural body forming operation S 1  is an operation of fabricating a structural body  130  having a hollow portion in the central portion thereof in which a QD ( 140  in  FIG. 8 ) is to be accommodated. The structural body forming operation S 1  includes: forming granules by mixing Bi 2 O 3 —ZnO—B 2 O 3 -based low melting point glass frit powder and a YAG-based yellow fluorescent material, the low melting point glass frit powder having a softening point of 650° C. or below and a refractive index of 1.7 or greater; shaping the mixture into the shape of an rectangular frame; and firing the shaped mixture, whereby an rectangular frame-shaped structural body  130  is fabricated. 
         [0059]    Afterwards, as illustrated in  FIG. 7 , the structural body disposing operation S 2  is performed to arrange the structural body  130 , fabricated in the structural body forming operation S 1 , on a first glass substrate  110 . In the structural body disposing operation S 2 , the structural body  130  may be fixed on top of the first glass substrate  110  by means of a sealant  150 . In the structural body disposing operation S 2 , the sealant  150  in the form of a paste may be applied to the bottom surface of the structural body  130 , i.e. a bonding surface to be bonded to the first glass substrate  110 . In addition, in the structural body disposing operation S 2 , the sealant  150  in the form of a paste may be printed on the first glass substrate  110  in a shape corresponding to the bottom surface of the structural body  130 . 
         [0060]    The sealant  150  acting as a medium by which the structural body  130  is connected to the first glass substrate  110  as above may be formed of a low melting point glass frit, the softening temperature of which is lower than the softening temperature of the first glass substrate  110 . For example, the sealant  150  may be formed of a V 2 O 5 —P 2 O 5 -based glass frit or a Bi 2 O 3 —B 2 O 3 —ZnO-based glass frit. 
         [0061]    Thereafter, as illustrated in  FIG. 8 , the QD accommodating operation S 3  is performed to dispose the QD  140  within the hollow portion of the structural body  130 . In the QD accommodating operation S 3 , a QD material that converts the color (wavelength) of a portion of light emitted by a blue LED into yellow light is accommodated within the hollow portion of the structural body  130 . 
         [0062]    Afterwards, as illustrated in  FIG. 9 , the second glass substrate disposing operation S 4  is performed to arrange a second glass substrate  120  on the structural body  130  such that the second glass substrate  120  faces the first glass substrate  110 . In the second glass substrate disposing operation S 4 , the second glass substrate  120  is fixed on top of the structural body  130  by means of a sealant  150  formed of a low melting point glass frit, the composition of which is identical to the composition of the sealant disposed between the first glass substrate  110  and the structural body  130 . In the second glass substrate disposing operation S 4 , the sealant  150  in the form of a paste may be applied to the top surface of the structural body  130  or may be printed on the bottom surface of the glass substrate  120  in a shape corresponding to the top surface of the structural body  130 , in the same manner as in the structural body disposing operation S 2 . 
         [0063]    Finally, the sealing operation S 5  is performed to bond the first glass substrate  110  and the structural body  130  to each other and the structural body  130  and the second glass substrate  120  to each other. In the sealing operation S 5 , the sealant  150  disposed between the first glass substrate  110  and the structural body  130  and between the structural body  130  and the second glass substrate  120  is irradiated with laser beams, whereby the first glass substrate  110  and the structural body  130  are hermetically bonded by laser sealing and the structural body  130  and the second glass substrate  120  are hermetically bonded by laser sealing. 
         [0064]    Upon the completion of the sealing operation S 5  as above, an LED color conversion substrate ( 100  in  FIG. 1 ) is fabricated. When the LED color conversion substrate  100  is fabricated by the fabrication method according to the present embodiment, a related-art multilayer coating process intended to protect the QD can be omitted, thereby reducing fabrication costs compared to those of the related art. In addition, a related-art etching process required for the accommodation of the QD can be omitted, whereby limitations on the thickness of the substrate are removed. In particular, since the structural body  130  is fabricated by powder compaction, the structural body  130  can be mass-produced at a lower cost. 
         [0065]    In the method of fabricating an LED color conversion substrate according to the present embodiment, the method of fabricating a single cell has been described. However, it is possible to fabricate a bulk color conversion substrate ( 200  in  FIG. 3 ) for an array of a plurality of LEDs applicable as a backlight source of a display or a light source of a wide area lighting device by fabricating a plurality of structural bodies  130 , arranging the plurality of structural bodies  130  on a single first glass substrate  110 , and performing a series of the QD accommodating operation S 3 , the second glass substrate disposing operation S 4 , and the sealing operation S 5  as above. In addition, after the bulk color conversion substrate ( 200  in  FIG. 3 ) is fabricated through this process, the bulk color conversion substrate ( 200  in  FIG. 3 ) may be diced into cells defined by the plurality of structural bodies  130  respectively, thereby facilitating the mass production of color conversion substrates ( 100  in  FIG. 1 ) applied to individual LEDs. 
         [0066]    Hereinafter, a method of fabricating an LED color conversion substrate according to another exemplary embodiment will be described with reference to  FIG. 10  to  FIG. 13 . 
         [0067]    As illustrated in  FIG. 10 , the method of fabricating an LED color conversion substrate according to the present embodiment includes paste preparing operation S 1 , structural body forming operation S 2 , QD accommodating operation S 3 , second glass substrate disposing operation S 4 , and sealing operation S 5 . 
         [0068]    First, in the paste preparing operation S 1 , a paste is prepared by adding and mixing a YAG-based yellow fluorescent material and low melting point glass frit powder. Afterwards, as illustrated in  FIG. 11 , in the structural body forming operation S 2 , a structural body  130  having a hollow portion is formed by printing the paste prepared in the paste preparing operation S 1  on a first glass substrate  110 . Thereafter, as illustrated in  FIG. 12  and  FIG. 13 , a series of operations including the QD accommodating operation S 3 , the second glass substrate disposing operation S 4 , and the sealing operation S 5  may be sequentially performed. Detailed descriptions of the QD accommodating operation S 3 , the second glass substrate disposing operation S 4 , and the sealing operation S 5  identical to those described in the former embodiment will be omitted. 
         [0069]    The method of fabricating an LED color conversion substrate according to the present embodiment forms the structural body  130  on the first glass substrate  110  by printing, unlike the method of fabricating an LED color conversion substrate according to the former embodiment in which the structural body  130  is formed by powder compaction. According to the present embodiment, the sealant  150  disposed between the first glass substrate  110  and the structural body  130  in the method of fabricating an LED color conversion substrate according to the former embodiment can be omitted. Accordingly, in the method of fabricating an LED color conversion substrate according to the present embodiment, the sealant  150  may be disposed only between the structural body  130  and the second glass substrate  120 , and is subsequently bonded thereto by laser sealing. 
         [0070]    The foregoing descriptions of specific exemplary embodiments of the present disclosure have been presented with respect to the drawings. They are not intended to be exhaustive or to limit the present disclosure to the precise forms disclosed, and obviously many modifications and variations are possible for a person having ordinary skill in the art in light of the above teachings. 
         [0071]    It is intended therefore that the scope of the present disclosure not be limited to the foregoing embodiments, but be defined by the Claims appended hereto and their equivalents. 
       DESCRIPTION OF REFERENCE NUMERALS 
       [0000]    
       
           100 ,  200 : color conversion substrate 
           110 : first glass substrate 
           120 : second glass substrate 
           130 : structural body 
           140 : quantum dot