Patent Publication Number: US-2023142036-A1

Title: Color conversion panel and display device including the same

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a Continuation of co-pending U.S. patent application Ser. No. 17/651,162, filed on Feb. 15, 2022, which is a Continuation of U.S. patent application Ser. No. 17/121,207, filed on Dec. 14, 2020 (issued on Mar. 8, 2022 as U.S. Pat. No. 11,269,217), which is a Continuation of U.S. patent application Ser. No. 16/541,282, filed on Aug. 15, 2019 (issued on Dec. 29, 2020 as U.S. Pat. No. 10,877,318), which is a Continuation of U.S. patent application Ser. No. 15/870,053, filed on Jan. 12, 2018 (issued on Sep. 10, 2019 as U.S. Pat. No. 10,409,110), which claims priority to and the benefit of Korean Patent Application No. 10-2017-0097724 filed in the Korean Intellectual Property Office on Aug. 1, 2017, the entire contents of which are herein incorporated by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to a display device and, more specifically, to a color conversion display panel and a display device including the same. 
     DISCUSSION OF THE RELATED ART 
     A liquid crystal display device may include two field generating electrodes, a liquid crystal layer, a color filter, and a polarization layer. Light emitted from a light source reaches a viewer through the liquid crystal layer, the color filter, and the polarization layer. Light loss may occur in the polarizing layer, the color filter, or the other various layers of the display device. Similarly, light loss may occur in other forms of display devices such as an organic light emitting diode display. 
     Some forms of display devices include a color conversion display panel. Color conversion display panels may use semiconductor nanocrystals, such as quantum dots, to provide the display device with high color reproducibility and reduced light loss generate in a polarization layer or a color filter. 
     SUMMARY 
     A color conversion display panel includes a substrate. A color conversion portion is disposed on the substrate. The color conversion portion includes a semiconductor nanocrystal. A transmission portion is disposed on the substrate. A blue light blocking filter is disposed between the substrate and the color conversion portion. The blue light blocking filter includes a first convex portion that protrudes toward the substrate. The transmission portion includes a first region including a scatterer and a second region including a second convex portion that protrudes toward the substrate. 
     A color conversion display panel includes a substrate having a first surface and a second surface opposite to the first surface. A color conversion portion is disposed on the first surface of the substrate. The color conversion portion includes a semiconductor nanocrystal. A transmission portion is disposed on the first surface of the substrate. The substrate includes a plurality of convex portions in the second surface. 
     A display device includes a lower display panel including a plurality of thin film transistors. A color conversion display panel at least partially overlaps the lower display panel. A liquid crystal layer is disposed between the lower display panel and the color conversion display panel. The color conversion display panel includes a substrate. A color conversion portion including a semiconductor nanocrystal is disposed between the substrate and the liquid crystal layer. A transmission portion is disposed between the substrate and the liquid crystal layer. A blue light blocking filter is disposed between the substrate and the color conversion portion, and includes a convex portion that protrudes toward the substrate. The transmission portion includes a first region including a first scatterer and a second region including a second scatterer and a convex portion that protrudes toward the substrate. A volume fraction of the first scatterer included in the first region is greater than a volume fraction of the second scatterer included in the second region. 
     A display device includes a lower display panel including a plurality of thin film transistors. A color conversion display panel at least partially overlaps the lower display panel. A liquid crystal layer is disposed between the lower display panel and the color conversion display panel. The color conversion display panel includes a substrate. A color conversion portion including a semiconductor nanocrystal is disposed between the substrate and the liquid crystal layer. A transmission portion is disposed between the substrate and the liquid crystal layer. A blue light blocking filter is disposed between the substrate and the color conversion portion, and includes a convex portion that protrudes toward the substrate. The transmission portion includes a first region including a scatterer and a second region including a convex portion that protrudes toward the substrate. The second region does not include the scatterer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete appreciation of the present disclosure and many of the attendant aspects thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: 
         FIG.  1    is a top plan view illustrating pixels of a display device according to an exemplary embodiment of the present invention; 
         FIG.  2    is a cross-sectional view taken along a line II-II′ of  FIG.  1    according to an exemplary embodiment of the present invention; 
         FIG.  3    is a cross-sectional view taken along a line II-II′ of  FIG.  1    according to an exemplary embodiment of the present invention; 
         FIG.  4    is a cross-sectional view taken along a line II-II′ of  FIG.  1    according to an exemplary embodiment of the present invention; 
         FIG.  5    is a cross-sectional view taken along a line II-II′ of  FIG.  1    according to an exemplary embodiment of the present invention; 
         FIG.  6    is a cross-sectional view taken along a line II-II′ of  FIG.  1    according to an exemplary embodiment of the present invention; and 
         FIG.  7    is a cross-sectional view taken along a line II-II′ of  FIG.  1    according to an exemplary embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     In describing exemplary embodiments of the present disclosure illustrated in the drawings, specific terminology is employed for sake of clarity. However, the present disclosure is not intended to be limited to the specific terminology so selected, and it is to be understood that each specific element includes all technical equivalents which operate in a similar manner. 
     In the figures and the description thereof, like numerals may refer to like or similar elements. 
     In the drawings, the size and thickness of layers, films, panels, regions, etc., may be exaggerated for clarity. 
     It will be understood that when an element such as a layer, film, region, or substrate is referred to as being “on” another element, it can be directly on the other element or intervening elements may also be present. 
     Further, in the specification, the phrase “in a plan view” may mean that an object portion is viewed from above, and the phrase “in a cross-section” may mean that an object is viewed from a side though by vertically cutting the object. 
     Hereinafter, a color conversion display panel and a display device including the same, in accordance with an exemplary embodiment of the present invention, will be described with reference to  FIG.  1    and  FIG.  2   .  FIG.  1    is a top plan view illustrating pixels of a display device according to an exemplary embodiment of the present invention, and  FIG.  2    is a cross-sectional view taken along a line II-II′ of  FIG.  1   . 
     The display device, according to an exemplary embodiment of the present invention, may include a light unit  500  (e.g. a backlight), a lower display panel  100 , a color conversion display panel  30 , and a liquid crystal layer  3  disposed between the lower display panel  100  and the color conversion display panel  30 . 
     The light unit  500  may include a light source for generating light having a first wavelength, and a light guide for receiving the light generated from the light source and guiding the light towards the lower display panel  100  and the color conversion display panel  30 . The first wavelength may be in a range of about 400 nm to about 500 nm, or may be in a range of about 420 nm to about 480 nm. The light source may emit blue light. For example, the light source may be a blue light emitting diode (LED). 
     A light unit including a white light source or an ultraviolet light source may be used instead of the light unit  500  including the above-described blue light source. Hereinafter, the display device using the light unit  500  including the blue light source will be described. 
     The lower display panel  100  includes a plurality of transistors, and the lower display panel  100  at least partially overlaps the color conversion display panel  30 . The liquid crystal layer  3  includes a plurality of liquid crystal molecules  31 . 
     According to an exemplary embodiment of the present invention, the display device may include a first polarization layer  12  disposed between a first substrate  110  and the light unit  500 . The first polarization layer  12  may linearly polarize the light generated in the light unit  500 . 
     A coated polarization layer, a film polarization layer, a wire grid polarizer, or the like may be used as the first polarization layer  12 . The first polarization layer  12  may be disposed on a surface of the first substrate  110  in various ways, for example, by being attached as a film, formed as a coating, or formed through printing. 
     The lower display panel  100  includes a gate line  121  that extends in a first direction. The lower display panel  100  further includes a gate electrode  124 , a gate insulating layer  140  disposed on the gate line  121 , and a semiconductor layer  154  disposed on the gate insulating layer  140 . A data line  171  is disposed on the gate insulating layer  140 . The data line  171  extends in a second direction and is connected with a source electrode  173 . A drain electrode  175  is disposed in a same layer as the source electrode  173 . A passivation layer  180  is disposed on the data line  171  and the drain electrode  175 . 
     The semiconductor layer  154  is disposed on the gate electrode  124  and may include a channel between the source electrode  173  and the drain electrode  175 . The gate electrode  124 , the semiconductor layer  154 , the source electrode  173 , and the drain electrode  175  may together constitute one transistor Tr. 
     A pixel electrode  191  and a first alignment layer  11  are sequentially disposed on the passivation layer  180 . The pixel electrode  191  is electrically connected to the drain electrode  175  through a contact hole  185  of the passivation layer  180 . 
     The pixel electrode  191  may be disposed in a matrix form, and the pixel electrode  191  may have various shapes. Although the pixel electrode  191  is illustrated as having a planar shape, the pixel electrode  191  may have other shapes such as a slit-shaped pixel electrode. 
     The color conversion display panel  30  includes a second substrate  310  that at least partially overlaps the first substrate  110 . A light blocking member  320  may be disposed between the second substrate  310  and the lower display panel  100 . 
     The light blocking member  320  is disposed between a first color conversion portion  330 R and a second color conversion portion  330 G, between the second color conversion portion  330 G and a transmission portion  330 B, and between the transmission portion  330 B and the first color conversion portion  330 . The light blocking member  320  may define a region in which the first color conversion portion  330 R, the second color conversion portion  330 G, and the transmission portion  330 B are disposed. 
     The light blocking member  320  may include a material that absorbs incident light or a material that reflects light. For example, a light blocking member  320  including a metal material may increase light transmission efficiency by reflecting light introduced from the first color conversion portion  330 R, the second color conversion portion  330 G, and the transmission portion  330 B toward the first color conversion portion  330 R, the second color conversion portion  330 G, and the transmission portion  330 B, respectively. 
     A first passivation layer  321  may be disposed between the light blocking member  320  and the color conversion portions  330 R and  330 G, and between the light blocking member  320  and the transmission portion  330 B. The first passivation layer  321  may at least partially overlap a front surface of the second substrate  310 . 
     The first passivation layer  321  may include a material having a lower refractive index than those of the second substrate  310 , the blue light blocking filter  325 , and the transmission portion  330 B. For example, the refractive index of the second substrate  310  may be about 1.5, and the refractive indexes of the transmission portion  330 B and the blue light blocking filter  325  may each be about 1.7. According to an exemplary embodiment of the present invention, the refractive index of the first passivation layer  321  may be about 1.2. 
     The first passivation layer  321  may have a surface that faces the liquid crystal layer  3 , and the surface may include a plurality of recess portions  321   a . The recess portions  321   a  may be regularly arranged at a constant distance. 
     According to an exemplary embodiment of the present invention, one recess portion  321   a  may be positioned to at least partially overlap one pixel, but the present specification is not limited thereto. In addition, recess portions  321   a  disposed adjacently may either be connected to each other, or may be spaced apart front each other. The recess portions  321   a  may have a constant curvature, such as a semi sphere, as is illustrated herein, or the recess portions  321   a  may have an irregular curvature. 
     In general, where a light is introduced from a first material having a relatively large refractive index into a second material having a relatively small refractive index, the light may he totally reflected at an interface between the first material and the second material when an incidence angle of the light is greater than a particular angle. Light passing through the transmission portion  330 B or the blue light blocking filter  325  is introduced into the first passivation layer  321 . In this case, the transmission portion  330 B or the blue light blocking filter  325  has a refractive index that is greater than that of the first passivation layer  321 . Accordingly, total reflection may occur for light that is introduced at a critical angle, as a minimum. 
     According to exemplary embodiments of the present invention, the first passivation layer  321  includes the recess portions  321   a  at the interface. The recess portions  321   a  may vary an incidence angle of light introduced to the interface to reduce total reflection occurring at the interface. Since an amount of light emitted to the outside of the second substrate  310  increases as the total reflection decreases, light-emitting efficiency of the display device may increase. 
     A blue light blocking filter  325  may be disposed between the first passivation layer  321  and the first color conversion portion  330 R, and between the first passivation layer  321  and the second color conversion portion  330 G. The blue light blocking filter  325  may be disposed only in regions for emitting red and green light and not in a region for emitting blue light. 
     The blue light blocking filter  325  may include a plurality of convex portions  325   a  which face the second substrate  310 . The convex portions  325   a  may be regularly arranged at a constant distance. 
     The convex portion  325   a  of the blue light blocking filter  325  and the recess portion  321   a  of the first passivation layer  321  may have complementary shapes. The present specification has described the exemplary embodiment in which the blue light blocking filter  325  includes the aim convex portion  325   a . However, a shape of the convex portion  325   a  included in the blue light blocking filter  325  may be changed depending on a shape of the recess portion  321   a  included in the first passivation layer  321 . 
     Similar to the recess portions  321   a , one convex portion  325   a  may be disposed to correspond to one pixel. In addition, the convex portions  325   a  disposed adjacently may be connected to each other, or may be spaced apart from each other. Further, although the present specification has described the convex portions  325   a  having a constant curvature, the convex portions  325   a  may have an irregular curvature. 
     The blue light blocking filter  325  may block or absorb blue light emitted from the light unit  500 . Blue light from the light unit  500  is converted into red or green light by a semiconductor nanocrystal. In this case, some of the blue light may be emitted through the second substrate  310  without being converted. The blue light blocking filter  325  may have a single-layer structure or a stacked structure of a plurality of layers to prevent the emission of unconverted blue light. 
     The blue light blocking filter  325  may include any material for performing the above-mentioned effects, and may include a yellow color filter as an example. A refractive index of the blue light blocking filter  325  including the yellow color filter may be about 1.7, and it may have a refractive index that is greater than that of the first passivation layer  321 . 
     Light is totally reflected at an interface between the blue light blocking filter  325  having a large refractive index and the first passivation layer  321  having a small refractive index when an incidence angle is greater than a certain angle in a case where the light is introduced from the blue light blocking filter  325  into the first passivation layer  321 . However, the color conversion display panel  30 , according to an exemplary embodiment of the present invention, may include an irregular pattern formed between the first passivation layer  321  and the blue light blocking filter  325 , thereby changing an incidence angle of light to reduce the total reflection occurring at the interface. 
     The first color conversion portion  330 R and the second color conversion portion  330 G may be disposed between the blue light blocking filter  325  and the liquid crystal layer  3 , and the transmission portion  330 B including a first region  330 B_ 1  and a second region  330 B_ 2  may be disposed between the second substrate  310  and the lower display panel  100 . 
     The first color conversion portion  330 R may include a first semiconductor nanocrystal  331 R. The second color conversion portion  330 G may include a second semiconductor nanocrystal  331 G. Light introduced into the first color conversion portion  330 R may be converted into red light by the first semiconductor nanocrystal  331 R, and may then be emitted from the first color conversion portion  330 R. Light introduced into the second color conversion portion  330 G may be converted into green light by the second semiconductor nanocrystal  331 G, and may then be emitted from the second color conversion portion  330 G. 
     The first semiconductor nanocrystal  331 R may include a red phosphor and/or a red quantum dot for converting the introduced blue light into red light. The second semiconductor nanocrystal  331 G may include a green phosphor and/or a green quantum dot for converting the introduced blue light into green light. 
     The red quantum dot and the green quantum dot may be selected from a group II-VI compound, a group III-V compound, a group IV-VI compound, a group IV element, a group IV compound, and a combination thereof. 
     For the group II-VI compound, a binary compound selected from CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS, and a mixture thereof; a ternary compound selected from CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS, and a mixture thereof; or a quaternary compound selected from HgZnTeS, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe, and a mixture thereof, may be employed. For the group III-V compound, a binary compound selected from GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, and a mixture thereof; a ternary compound selected from GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, and a mixture thereof; or a quaternary compound selected from GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, GaAlNP, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, and a mixture thereof, may be employed. For the group IV-VI compound, a binary compound selected from SnS, SnSe, SnTe, PbS, PbSe, PbTe, and a mixture thereof; a ternary compound selected from SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, and a mixture thereof; or a quaternary compound selected from SnPbSSe, SnPbSeTe, SnPbSTe, and a mixture thereof, may be employed. For the IV group element, Si, Ge, or a mixture thereof may, be selected. For the IV group compound, a binary compound selected from SiC, SiGe, and a mixture thereof may be employed. 
     In this case, the binary compound, the ternary compound, or the quaternary compound may exist in a uniform concentration or in a partially different concentration in particles. 
     The quantum dot may include multiple quantum dots, and each of the quantum dots may have a core/shell structure in which one quantum dot (shell) surrounds another quantum dot (core). An interface between a core and a shell may have a concentration gradient such that a concentration of an element in the shell decreases toward a center thereof. 
     The quantum dot may have a full width at half maximum (FWHM) of the light-emitting wavelength spectrum that is equal to or less than about 45 nm, preferably equal to or less than about 40 nm, and more preferably equal to or less than about 30 nm, and in this range, color purity or color reproducibility may be increased. In addition, since light emitted through the quantum dot is emitted in all directions, a viewing angle of light may be increased. 
     The quantum dot may have various shapes known in the art, for example, the quantum dot may have a shape such as a nanoparticle having a spherical shape, a pyramid shape, a multi-arm shape, or a cubic shape, or may be a nanotube, a nanowire, a nanofiber, a planar nanoparticle, etc. 
     The red phosphor may include at least one of (Ca, Sr, Ba)S, (Ca, Sr, Ba) 2 Si 5 N 8 , CaAlSiN 3 , CaMoO 4 , and Eu 2 Si 5 N 8 , but other phosphors may alternatively be used. 
     The green phosphor may include at least one of yttrium aluminum garnet (YAG), (Ca, Sr, Ba) 2 SiO 4 , SrGa 2 S 4 , barium magnesium aluminate (BAM), α-SiAlON, β-SiAlON, Ca 3 Sc 2 Si 3 O 12 , Tb 3 Al 5 O 12 , BaSiO 4 , CaAlSiON, and (Srl-xBax)Si 2 O 2 N 2 . In this case, the x may be a number between 0 and 1. 
     The transmission portion  330 B may include the first region  330 B_ 1  adjacent to the liquid crystal layer  3  and the second region  330 B_ 2  adjacent to the first passivation layer  321 . 
     The second region  330 B_ 2  may include a convex portion  330 B_ 2   a  corresponding to the recess portion  321   a  of the first passivation layer  321 , similar to the aforementioned blue light blocking filter  325 . The second region  330 B_ 2  may include a convex, portion  330 B_ 2   a  which faces the second substrate  310 . Total reflection of light may be reduced at an interface between the second region  330 B_ 2  and the first passivation layer  321 , and an amount of light emitted to the outside of the second substrate  310  may increase. 
     The transmission portion  330 B may allow light emitted from the light unit  500  and introduced into the transmission portion  330 B to pass therethrough. The transmission portion  330 B may include a polymer material that allows blue light supplied from the light unit  500  to pass therethrough. The transmission portion  330 B disposed in a region for emitting blue light may pass the introduced blue light without a separate phosphor or quantum dot. 
     According to exemplary embodiments of the present invention, the first region  330 B_ 1  may include a scatterer  332 , and the second region  330 B_ 2  might not include the scatterer  332 . The scatterer  332  may scatter light introduced into the first region  330 B_ 1  of the transmission portion  330 B so as to increase an amount of emitted light or make front luminance and side luminance more uniform. For example, the scatterer  332  may include at least one of TiO 2 , Al 2 O 3 , and SiO 2 , or an alternative scattering material. According to exemplary embodiments of the present invention, the second region  330 B_ 2  does not include the scatterer  332 , thereby preventing light from being returned to the liquid crystal layer immediately before being emitted. Accordingly, the amount of light emitted to the outside of the second substrate  310  may be increased. In addition, according to an exemplary embodiment of the present invention, the first color conversion portion  330 R and/or the second color conversion portion  330 G may include the scatterer  332 . 
     According to exemplary embodiments of the present invention, the first color conversion portion  330 R and the second color conversion portion  330 G may include the scatterer  332  having substantially a same central diameter. The scatterer  332  included in the transmission portion  330 B may have a central diameter that is smaller than those of the first color conversion portion  330 R and second color conversion portion  330 G. As used herein, “central diameter” indicates an average value of diameters of a plurality of scatterers  332  included in the color conversion portions  330 R and  330 G or the transmission portion  330 B, and the diameters of the scatterers  332  may achieve a Gaussian distribution. 
     For example, the first color conversion portion  330 R and the second color conversion portion  330 G may each include the scatterer  332  having a central diameter of about 200 to 220 nm, and the transmission portion  330 B may include the scatterer  332  having a central diameter of about 170 to 190 nm. In addition, volume fractions of the scatterers  332  included in the first color conversion portion  330 R and the second color conversion portion  330 G may be substantially the same, and the volume fraction of the scatterer  332  included in the transmission portion  330 B may be greater than that of the scatterer  332  included in the first color conversion portion  330 R or the second color conversion portion  330 G. For example, the volume fraction of the scatterer  332  included in the transmission portion  330 B is substantially the same as a sum of the volume fractions of the first semiconductor nanocrystal  331 R of the first color conversion portion  330 R and the scatterer  332  included in the first color conversion portion  330 R. Alternatively, the volume fraction of the scatterer  332  included in the transmission portion  330 B is substantially the same as a sum of the volume fractions of the second semiconductor nanocrystal  331 G of the second color conversion portion  330 G and the scatterer  332  included in the second color conversion portion  330 G. 
     The first region  330 B_ 1  may have a similar composition to the second region  330 B_ 2 , except for the inclusion of the scatterer  332 .  FIG.  2    illustrates the first region  330 B_ 1  and the second region  330 B_ 2  which are disposed at different layers, but the present specification is not limited thereto. For example, they may be provided as one layer. 
     The transmission portion  330 B may further include a blue pigment and/or a dye. The blue pigment and the dye may absorb at least one of red light and green light included in external light to thereby prevent color reproducibility deterioration. 
     A capping layer  340  may be disposed between the first color conversion portion  330 R, the second color conversion portion  330 G, the transmission portion  330 B, and the liquid crystal layer  3 . The capping layer  340  may overlap a front surface of the second substrate  310 . 
     The capping layer  340  may increase light-emitting efficiency by reflecting light generated from the first color conversion portion  330 R and the second color conversion portion  330 G. 
     The capping layer  340  may include a plurality of optical filter layers, and the capping layer may have a structure in which layers haying different refractive indexes are alternately arranged along a direction substantially perpendicular to the plane of the second substrate  310 . The capping layer  340  may be formed by alternately arranging the layers having different refractive indexes and may include a multi-layer structure of about 10 to 20 layers, but other configurations may be used. The capping layer  340  may have a structure in which a silicon oxide (SiOx) film and a silicon nitride (SiNy) film are alternately arranged, but other configurations may be used. For example, a titanium oxide, a tantalum oxide, a hafnium oxide, and/or a zirconium oxide may be used as a material having a relatively high refractive index, and SiCOz may be used as a material having a relatively low refractive index. In the SiOx, SiNy, and SiCOz, x, y, and z as factors determining the chemical composition ratio may be controlled depending on process conditions when forming the layers. 
     When a layer of the layers constituting the capping layer  340 , which is most adjacent to the first color conversion portion  330 R, the second color conversion portion  330 G, and the transmission portion  330 B, is formed of a silicon nitride film, the silicon nitride film may serve as a passivation layer. The capping layer  340  may prevent the first color conversion portion  330 R, the second color conversion portion  330 G, and the transmission portion  330 B from being damaged during the manufacturing processes. The semiconductor nanocrystals included in the first color conversion portion  330 R and the second color conversion portion  330 G may be damaged or quenched by moisture and high-temperature processes. The silicon nitride film may prevent this problem. 
     A planarization layer  350  is disposed between the capping layer  340  and the liquid crystal layer  3 . The planarization layer  350  may serve to planarize a surface of a constituent element disposed between the planarization layer  350  and the second substrate  310 . 
     A second polarization layer  22  may be disposed between the planarization layer  350  and the liquid crystal layer  3 . The second polarization layer  22  serves to polarize light passing through the light unit  500 , the lower display panel  100 , and the liquid crystal layer  3 . 
     A coated polarization layer, a film polarization layer, a wire grid polarizer, or the like may be used as the second polarization layer  22 . The second polarization layer  22  may include a metal. The polarization layer  22  may include a plurality of bar-like nanopatterns according to an exemplary embodiment of the present invention, and a width of each nanopattern may be several nanometers. 
     An insulating layer  360 , a common electrode  370 , and a second alignment layer  21  may be sequentially disposed between the second polarization layer  22  and the liquid crystal layer  3 . 
     The insulating layer  360  may isolate the second polarization layer  22  made of metal from the common electrode  370 . When the second polarization layer  22  is not made of metal, the insulating layer  360  may be omitted. 
     The common electrode  370  receiving a common voltage may form an electric field together with the pixel electrode  191 . According to some exemplary embodiments of the present invention, the common electrode  370  may be disposed in the lower display panel  100 . 
     The second alignment layer  21  may include a same material as the first alignment layer  11 , and may be manufactured through a same process. 
     The above-described display device can provide light with increased color purity by including the light unit  500  for providing blue light and the color conversion portions  330 R and  330 G for emitting red and green light therethrough. In addition, since the second polarization layer  22  included in the color conversion display panel  30  is relatively thin, e.g. on the order of several nanometers, a path through which light passes is short to minimize light distortion. 
     Further, when total reflection may be reduced by allowing light passing through the color conversion portions  330 R and  330 G and the transmission portion  330 B to pass through a concave or convex interface, the amount of light emitted to the outside of the second substrate  310  may increase. 
     Hereinafter, a display device according to an exemplary embodiment of the present invention will be described with reference to  FIG.  3    to  FIG.  7   .  FIG.  3   ,  FIG.  4   ,  FIG.  5   ,  FIG.  6   , and  FIG.  7    are cross-sectional views that illustrate a modification of what is illustrated in  FIG.  2   . 
     First, referring to  FIG.  3   , the first color conversion portion  330 R and the second color conversion portion  330 G may be disposed between the blue light blocking filter  325  and the liquid crystal layer  3 , and the transmission portion  330 B may be disposed between the second substrate  310  and the lower display panel  100 . 
     The transmission portion  330 B may include a convex portion  330 Ba that faces the second substrate  310 . The convex portion  330 Ba included in the transmission portion  330 B may have a complementary shape to that of the recess portion  321   a  of the first passivation layer  321 . 
     The present specification has described the exemplary embodiment in which the convex portion  330 Ba of the transmission portion  330 B directly contacts the recess portion  321   a  of the first passivation layer  321 , but the present invention is not limited thereto. For example, a buffer layer or the like may be disposed between the transmission portion  330 B and the recess portion  321   a.    
     The transmission portion  330 B may include the scatterer  332 , and may include a first region R 1  that at least partially overlaps the color conversion portions  330 R and  330 G along a first direction and a second region R 2  including the convex portion  330 Ba. 
     The transmission portion  330 B may allow light emitted from the light unit  500  and introduced into the transmission portion  330 B to pass therethrough. The transmission portion  330 B may include a polymer material that allows blue light supplied from the light unit  500  to pass therethrough. The transmission portion  330 B is positioned in a region for emitting blue light without a separate phosphor or quantum dot. 
     The first region R 1  and the second region R 2  of the transmission portion  330 B may include the scatterer  332 . The scatterer  332  may be disposed in a region where the convex portion  330 Ba is disposed. A volume fraction of the scatterer  332  included in the first region R 1  may be greater than that of the scatterer  332  included in the second region R 2 . For example, the volume ratio of the scatterer  332  may decrease from the first region R 1  to the second region R 2 , and the second region R 2  might not include the scatterer  332 . 
     The scatterer  332  may scatter light introduced into the transmission portion  330 B so as to increase an amount of emitted light or make front luminance and side luminance more uniform. 
     The description of other constituent elements may be at least similar to that of the elements described above with reference to  FIG.  1    and  FIG.  2   , and thus the description thereof will be omitted hereinafter. 
     Next, referring to  FIG.  4   , the second substrate  310  may include a plurality of recess portions  310   a . For example, the recess portions  310   a  may be disposed in a surface of the second substrate  310  which tares the liquid crystal layer  3 . The recess portions  310   a  may be regularly arranged at a constant distance. 
     According to an exemplary embodiment of the present invention, one recess portion  310   a  may be disposed to correspond to one pixel, but the present specification is not limited thereto. In addition, the recess portions  310   a  disposed adjacently may be connected to each other, or may be spaced apart from each other. Further, although the present specification has described the recess portions  310   a  having a constant curvature, the recess portions  310   a  may alternatively have an irregular curvature. 
     In general, where light is introduced from a first material having a relatively large refractive index, to a second material having a relatively small refractive index, light is totally reflected the interface between the first material and the second material when an incidence angle is greater than a particular angle. Light passing through the transmission portion  310 B or the blue light blocking filter  325  is introduced into the second substrate  310 . In this case, the transmission portion  330 B or the blue light blocking filter  325  has a refractive index that is greater than that of the second substrate  310 . Accordingly, total reflection may occur for light that is introduced at a critical angle or more at the interface. 
     According to an exemplary embodiment of the present invention, an incidence angle of light becomes different at an interface of the recess portion  310   a , and thus a total reflection problem caused by a refractive index may be reduced. Light efficiency of the display device may be increased by emitting light that is not able to be emitted to the outside of the second substrate  310  toward a user. 
     The blue light blocking filter  325  may include a plurality of convex portions  325   a  which face the second substrate  310 . The convex portions  325   a  may be regularly arranged at a constant distance. 
     The convex portion  325   a  of the blue light blocking filter  325  and the convex portion  325   a  is of the recess portion  310   a  may have complementary shapes. The present specification has described the exemplary embodiment in which the blue light blocking filter  325  includes the convex portion  325   a . However, a shape of the convex portion  325   a  included in the blue light blocking filter  325  may be changed depending on a shape of the recess portion  310   a  included in the second substrate  310 . 
     Similar to the recess portion  310   a , one convex portion  325   a  may be disposed to correspond to one pixel 
     In addition, the convex portions  325   a  disposed adjacently may be connected to each other, or may be spaced apart from each other. Further, although the present specification has described the convex portions  325   a  having a constant curvature, the convex portions  325   a  may alternatively have irregular curvatures. 
     The transmission portion  330 B may include a convex portion  330 Ba that faces the second substrate  310 . The convex portion  330 Ba included in the transmission portion  330 B may have a shape that meshes with the recess portion  310   a  of the second substrate  310 . The present specification has described the exemplary embodiment in which the convex portion  330 Ba of the aim transmission portion  330 B directly contacts the recess portion  310   a  of the second substrate  310 , but other arrangements may be used. For example, a buffer layer or the like may be disposed between the convex portion  330 Ba and the recess portion  310   a.    
     It is to be understood that to the extent that constituent elements are not described below, these elements are at least similar in description to corresponding elements that have already been described. 
     Next, referring to  FIG.  5   , according to an exemplary embodiment of the present invention, the second substrate  310  may include a plurality of convex portions  310   a  disposed in a second surface of the liquid crystal layer  3  which faces a first surface of the liquid crystal layer  3 . The convex portions  310   a  may be regularly arranged at a constant distance. 
     According to an exemplary embodiment of the present invention, one recess portion  310   a  may be disposed to correspond to one pixel. The recess portions  310   a  disposed adjacently may be connected to each other, or may be spaced apart from one another. Further, although the present specification has described the recess portion  310   a  having a constant curvature, the recess potion  310   a  may alternatively have an irregular curvature. 
     Light that is introduced from the second substrate  310  having a relatively large refractive index to the air having a relatively small refractive index is totally reflected at the interface therebetween when an incidence angle is greater than a particular angle. However, the color conversion display panel  30 , according to exemplary embodiments of the present invention, may include the convex portions  310   a  formed at the interface between the second substrate  310  and the air, thereby changing an incidence angle of light for the interface to reduce the total reflection. The amount of light emitted to the outside of the substrate  310  may thereby be increased. 
     Referring to  FIG.  6   , the second substrate  310 , according to an exemplary embodiment of the present invention, may include a pattern layer  311  disposed in a second surface of the liquid crystal layer  3  which faces a first surface of the liquid crystal layer  3 . The pattern layer  311  may include a plurality of convex portions  311   a . The convex portions  311   a  may be regularly arranged at a constant distance. 
     The pattern layer  311  may be disposed by various manufacturing processes such as by being patterned after being attached or applied in the form of a film on the second substrate  310 . The pattern layer  311  may be an embossing sheet including convex portions  311   a , or may be a polarization layer or an external light absorbing film including the convex portions  311   a.    
     The pattern layer  311  may include a transmissive material, and may include a material having a lower refractive index than the second substrate  310 . For example, the refractive index of the second substrate  310  may be about 1.5, and the pattern layer  311  may include an organic or inorganic material having a lower refractive index. 
     When light is introduced from the second substrate  310  having a relatively large refractive index to air having a relatively small refractive index, the light is totally reflected at the interface when an incidence angle is greater than a particular angle. However, the color conversion display panel  30 , according to an exemplary embodiment of the present invention, may provide a pattern layer  311  disposed at an interface between the second substrate  310  and the air. The pattern layer may have a refractive index which is between the refractive indexes of the second substrate  310  and the air, thereby changing an incidence angle of light for the interface to reduce the total reflection and an amount of light that is totally reflected. The amount of light emitted to the outside of the second substrate  310  may thereby be increased. 
     Referring to  FIG.  7   , the pattern layer  311 , according to exemplary embodiments of the present invention, may include a plurality of convex portions  311   a  corresponding to one pixel. For example, one pixel may overlap at least two convex portions  311   a . While it is described herein that one pixel overlaps four convex portions  311   a , is the present invention is not limited to this particular arrangement. For example, one pixel may overlap any number of convex portions. 
     Exemplary embodiments described herein are illustrative, and many variations can be introduced without departing from the spirit of the disclosure or from the scope of the appended claims. For example, elements and/or features of different exemplary embodiments may be combined with each other and/or substituted for each other within the scope of this disclosure and appended claims.