KR20130047199A - Quantum rod luminescent display device - Google Patents

Abstract

PURPOSE: A quantum rod luminescent display device is provided to improve full-color display quality by blocking the light of short wavelength passing through a quantum rod panel among the light emitted from a backlight unit. CONSTITUTION: A quantum rod panel(102) includes a first and a second substrate(110,170) and a quantum rod layer(155) having quantum rods. The quantum rod layer is formed between the first and the second substrate. A backlight unit(180) is formed in the lower part of the quantum rod panel. A light recycling sheet(197,198) is formed between the quantum rod panel and the backlight unit or in the upper part of the quantum rod panel to perform light selection reflection and penetration.

Description

Quantum rod luminescent display device

The present invention relates to a quantum rod light emitting display device, and more particularly, to a quantum rod light emitting display device in which light efficiency is maximized.

2. Description of the Related Art Flat panel displays having excellent characteristics such as thinning, lightening, and low power consumption have been widely developed and applied to various fields.

As a typical flat panel display device, a liquid crystal display device is most widely used.

However, referring to FIG. 1 (a diagram showing a schematic cross-sectional structure of a general liquid crystal display), a liquid crystal display device may include a first and a second substrate (not shown), an alignment layer (not shown), a color filter layer (not shown), and the like. The LCD panel 10 includes a liquid crystal panel 10 including a liquid crystal layer (not shown), a backlight unit 20 including a plurality of optical films 22, and upper and lower polarizers 31 and 32.

That is, the liquid crystal display device 1 requires a plurality of optical films 22 and polarizing plates 31 and 32 to realize gray levels, and a color filter layer (not shown) in a separate liquid crystal panel to express color. Needing).

Therefore, the light emitted from the light source (not shown) of the backlight unit 20 passes through the plurality of optical films 22, the color filter layers (not shown), and the polarizing plates 31 and 32, and most of them are lost to cause a decrease in transmittance. have.

That is, when the amount of light emitted from the light source (not shown) of the backlight unit 20 is 100, the amount of light finally transmitted through the liquid crystal display device 1 is about 5 to about 10, so that the transmission efficiency is very low, thereby displaying. As the device needs to increase the luminance of light emitted from the backlight unit in order to realize appropriate luminance, power consumption is increased, and further, there are many difficulties in reducing the manufacturing cost due to the large number of parts required for manufacturing.

Therefore, in recent years, there is a need for a new flat panel display device that can solve the problem of low transmittance of the liquid crystal display device to reduce power consumption and to reduce manufacturing costs due to relatively small components.

On the other hand, in order to meet the needs of the times, an organic light emitting device has been proposed, which does not require a separate polarizing plate, a color filter layer, and an optical film.

The organic electroluminescent device is a device that emits light by injecting charge into an organic light emitting layer formed between a cathode, which is an electron injection electrode, and an anode, which is a hole injection electrode, and then disappears after pairing electrons and holes.

The organic light emitting diode can be formed on a flexible substrate such as plastic, and has excellent color by self-luminous, and can be driven at a lower voltage (10V or less) than a liquid crystal display, and consumes power. Has the advantage of being relatively small.

However, such an organic light emitting device has a big difference in the lifespan of the organic light emitting material constituting the organic light emitting layer according to the color emitted, and in particular, the blue light emitting material has a relatively small life time, which is less than that of a conventional display device. Is occurring.

Therefore, there is still a need for a flat panel display having high transmittance, low power consumption, and at the same time having a lifespan similar to that of a liquid crystal display.

Disclosure of Invention The present invention has been made to solve the above-described problem, and does not require a polarizing plate, and thus provides a display device capable of reducing manufacturing costs by having a large transmission efficiency and having a simple configuration compared to a liquid crystal display device. do.

A quantum rod light emitting display device according to an exemplary embodiment of the present invention includes a quantum rod layer facing each other and a quantum rod layer interposed between the first and second substrates and provided with a plurality of quantum rods. A load panel; A backlight unit provided under the quantum load panel; And an optical recycling sheet disposed between at least one of the quantum rod panel and the backlight unit and at least one portion of an upper portion of the quantum rod panel, and configured to selectively reflect and selectively transmit light.

At this time, the backlight unit is characterized in that for generating blue or UV (ultra violet) light having a short wavelength of less than 430nm.

The optical recycling sheet is divided into first and second optical recycling sheets, and the first optical recycling sheet is positioned between the quantum rod panel and the backlight unit, and the second optical recycling sheet is disposed on the quantum rod panel. It is characterized by the location.

In this case, the first optical recycling sheet has a property of transmitting light having a short wavelength band of 430 nm or less and reflecting visible light having a wavelength band larger than 450 nm fluorescence from the quantum rod layer, and the second optical recycling sheet Visible light having a long wavelength band of 450 nm or more is transmitted, and light having a wavelength band smaller than 430 nm is reflected.

In addition, the first and second optical recycling sheet is laminated on a polymer film having a transparent and flexible property, at least two or more materials having different refractive indices alternated at least one or more times to form a laminated structure of three or more layers. The selective transmission reflection layer is provided.

In this case, the selective transmissive reflective layer is made of at least two or more materials of silicon oxide (SiO ₂ ), titanium oxide (TiO ₂ ), and tin oxide (SnO ₂ ), and the first and second light recycling sheets are the selective transmissive reflective layer. It is characterized by varying the number of layers of the material layer made of two or more materials having different thicknesses and refractive indices.

In addition, the first substrate includes first, second, and third pixel regions representing red, green, and blue, and the quantum rod layer includes quantum rods having different sizes for each of the first, second, and third pixel regions. It is characterized by one. At this time, the second substrate is characterized in that the red, green, blue color filter pattern corresponding to the first, second, and third pixel areas.

The first substrate may include first, second, and third pixel regions representing red, green, and blue colors, and the quantum rod layer may include quantum rods having the same size in each pixel region. The red, green, and blue color filter patterns are provided to correspond to the first, second, and third pixel areas.

In addition, the quantum rod layer may be separately formed on each of the pixel areas on the first substrate or formed on the entire display area for displaying an image.

The first substrate may further include gate lines and data lines crossing each other to define the pixel areas; A thin film transistor connected to the gate line and the data line is provided, and the first electrode is connected to the drain electrode of the thin film transistor.

In addition, the plurality of quantum rods provided in the quantum rod layer is characterized in that arranged in one direction, wherein the plurality of quantum rods are arranged in one direction, the polarization ratio PR _h in the horizontal direction and the polarization in the vertical direction When the ratio PR _v is defined as PR _h = I _h / (I _h + I _v ) and PR _v = I _v / (I _h + I _v ), respectively, the polarization ratio PR _{h in} the horizontal direction or the polarization in the vertical direction It means that the ratio PR _v has a value greater than 0.5 and less than 1, i.e., satisfying 0.5 < PR _h (or PR _v ) <

In addition, the quantum rod is composed of only the core, or the core and the shell surrounding the core, the shell has a form having a short axis and a long axis, characterized in that the ratio of short axis to long axis is 1: 1.1 to 1:30. In this case, the shape of the quantum rod is any one of the shape of sphere, ellipsoid, polyhedron, rod, the shell is a cut surface cut in the uniaxial direction of the quantum rod of any one of the shape of circle, ellipse, polygon It is characterized by forming.

In addition, the shell is a single layer or a multi-layer structure, wherein the shell is characterized in that the alloy (alloy), oxide-based or impurities doped material.

In addition, the core is characterized by consisting of a semiconductor, an alloy or a mixed material of II-VI, III-V, III-VI, VI-IV, IV on the periodic table.

The core of the quantum rod is made of any one of CdSe, CdS, CdTe, ZnO, ZnSe, ZnS, ZnTe, HgSe, HgTe, CdZnSe or a mixture of two or more materials when the core of the quantum rod is made of II-VI group, In the case of the III-V group, InP, InN, GaN, InSb, InAsP, InGaAs, GaAs, GaP, GaSb, AlP, AlN, AlAs, AlSb, CdSeTe, ZnCdSe, or a mixture of two or more materials In the case of consisting of Group VI-IV, it is made of any one of PbSe, PbTe, PbS, PbSnTe, Tl ₂ SnTe ₅ or a mixture of two or more materials.

The backlight unit may be an edge type backlight unit including a reflector, a light guide plate positioned on the reflector, a light source positioned on the side of the light guide plate, and a plurality of optical sheets positioned on the guided upper portion, or the reflector plate, And a direct type backlight unit including a light source positioned above the reflecting plate, a diffuser plate positioned above the light source, and a plurality of optical sheets positioned above the diffuser plate.

The present invention does not require a polarizing plate, so that the polarizing plate is provided, thereby reducing the luminance characteristic, and having a brighter light source to improve the lowered luminance characteristic. There is an effect to provide a quantum rod light emitting display having a.

In addition, in the quantum rod light emitting display device according to the present invention, light of a short wavelength passing through a quantum rod panel that may affect display quality among short wavelength band light emitted from the backlight unit is blocked by the second optical recycling sheet. Full color display quality can be improved.

In addition, the light reflected by the second optical recycling sheet toward the quantum rod panel is re-entered into the quantum rod layer provided in the quantum rod panel, thereby increasing the amount of light in the short wavelength band incident to the quantum rod layer. Since it has an effect of improving the brightness of the light emitted from the light source of the backlight unit, even if the brightness is reduced by the short wavelength of light reflected by the second light recycling sheet, the same level as the quantum rod light emitting display without the second light recycling sheet. Since the luminance characteristic has the advantage of reducing the power consumption for driving the light source.

Furthermore, the quantum rod light emitting display device according to an exemplary embodiment of the present invention further includes a first optical recycling sheet, which reflects light from the quantum rod layer toward the bottom of the quantum rod layer from the fluorescent light, thereby quantum rod layer. By recycling in order to proceed in the upper direction of the it is possible to further improve the brightness characteristics, further reducing the power consumption.

1 is a schematic cross-sectional view of a general liquid crystal display device;
2 shows the shape of a quantum rod;
3 is a diagram showing electrons and major states before and after applying an electric field to a quantum rod.
4 is a cross-sectional view of a quantum rod light emitting display device according to an exemplary embodiment of the present invention.
5A through 5C are cross-sectional views of quantum rod light emitting displays according to various modifications of the embodiments of the present invention.
6A and 6B schematically illustrate only a backlight unit and a quantum rod layer in a quantum rod light emitting display device that does not include an optical recycling sheet as a comparative example.

Hereinafter, a quantum rod light emitting display device according to the present invention will be described in detail with reference to the accompanying drawings.

First, the quantum rod used in the present invention will be briefly described.

As shown in FIG. 2, which illustrates a general shape of a quantum rod, the quantum rod 156 includes a core 157 which forms a center and a shell surrounding the core 157 ( 158). In this case, the quantum rod 156 is shown as an example consisting of a core 157 and a shell 158 surrounding the quantum rod 156, but the shell 158 may be omitted and made of only the core 157.

In this case, the core 157 may be formed in any one of a sphere, an ellipsoid, a polyhedron, and a rod shape.

On the other hand, when forming the quantum rod 156 with only the core 157, the core 157 is characterized in that it forms an ellipsoid or rod shape.

In addition, when the quantum rod includes a shell 158 surrounding the core 157, the core 157 may form any one of a sphere, an ellipsoid, a polyhedron, and a rod, and the shell 158 may surround the core 157. Has a long axis and a short axis, and a cut surface cut in the short direction of the quantum rod 156 may form one of a circle, an ellipse, and a polygonal shape.

In addition, the shell 158 may have a single layer or a multi-layered structure, and the shell 158 may be formed of a material in which any one or two or more of an alloy, an oxide-based material, or an impurity doped material is mixed.

At this time, the shell 158 is characterized in that the ratio of the short axis to the long axis can have a variety of ratios having a range of 1: 1.1 to 1:30.

In addition, the core 157 of the quantum rod 156 may be made of II-VI, III-V, III-VI, VI-IV, IV of the periodic table, an alloy, or a mixed material thereof.

That is, when the core 157 of the quantum rod 156 is made of group II-VI of the periodic table, any one or two or more materials of CdSe, CdS, CdTe, ZnO, ZnSe, ZnS, ZnTe, HgSe, HgTe, and CdZnSe This can be mixed.

In the case of the III-V group, one or more materials may be mixed with InP, InN, GaN, InSb, InAsP, InGaAs, GaAs, GaP, GaSb, AlP, AlN, AlAs, AlSb, CdSeTe, ZnCdSe have.

In addition, in the case of the VI-IV group, any one of PbSe, PbTe, PbS, PbSnTe, Tl ₂ SnTe ₅ or two or more materials may be mixed.

The quantum rod 156 having a ratio with such a material may have a fluorescence wavelength depending on the size of the core 157 even if the quantum rod 156 is made of the same material. The smaller the size of the core 157, the shorter the wavelength of fluorescence, and the larger the size, the longer the wavelength of fluorescence. Therefore, by adjusting the size of the core 157 is characterized in that the almost visible light in the visible range.

The quantum rod 156 made of a material as described above is shown in FIG. 3 (a diagram showing electrons and major states before and after applying an electric field to the quantum rod), the core 157 itself or the core 157. The shell 158 enclosing) has a long axis and a short axis.

Thus, before the electric field is applied in the direction of the long axis of the shell 158 or the core 157 having the long axis and the short axis, electrons and holes are formed in the core 157, but the shell 158 or the core is coupled. When an electric field is applied in the long axis direction of 157, electrons e and holes h are spatially separated between the core 157 or between the core 157 and the shell 158 to induce separation of the band gap. It is characterized in that it can be, according to the fluorescence or the amount of light emitted from the quantum rod 156 can be adjusted to implement the gray level.

The quantum rod 156 is another feature that can generate very strong fluorescence since its quantum yield is theoretically 100%.

 A configuration of a quantum rod light emitting display device according to an exemplary embodiment of the present invention using the quantum rod 156 having the above-described characteristics will be described.

FIG. 4 is a cross-sectional view of a quantum rod light emitting display device according to an exemplary embodiment of the present invention, and three neighboring pixel areas are illustrated, and a thin film transistor Tr is shown for only one pixel area P. Referring to FIG. In this case, for convenience of description, the region in which the thin film transistor is provided in each pixel region is defined as a switching region TrA.

As illustrated, the quantum rod light emitting display device 101 according to an exemplary embodiment of the present invention includes a first electrode 150 separately formed for each pixel region P, and a second electrode formed over the entire display region for displaying an image. 160 and a quantum rod panel including a first substrate 110 having a quantum rod layer 155 interposed between the first and second electrodes 150 and 160, and a second substrate 170 facing the first substrate 110. 102 and at least one light recycling sheet 197 and 198 which serve as selective transmission and reflection of light for improving light efficiency of the backlight unit 180 and the quantum rod layer 155.

The quantum rod light emitting display device 101 according to the exemplary embodiment of the present invention having the above structure absorbs the light emitted from the backlight unit 180 by the quantum rod layer 155 and internally recombines electrons and holes to emit light. Will fluoresce.

In this case, a plurality of quantum in the quantum rod layer 155 may be generated by applying a voltage to the first and second electrodes 150 and 160 positioned below and above the quantum rod layer 155 to generate electric fields having different electric strengths. The gray level is displayed by adjusting the recombination rate of electrons and holes in the rod, and the quantum rod layer 155 may generate red, green, and blue colors by varying the size of the quantum rod for each pixel region P. Since full color can be implemented, a full color image can be displayed.

First, the configuration of the first substrate 110 including the first and second electrodes 150 and 160 and the quantum rod layer 155 may be described as a transparent insulating substrate, for example, a transparent glass substrate or a flexible plastic substrate. On the first substrate 110 made of a metal material having low resistance, for example, aluminum (Al), aluminum alloy (AlNd), copper (Cu), copper alloy, molybdenum (Mo), molybdenum alloy (MoTi) Gate wirings (not shown) are formed extending in the first direction with one or more materials selected.

In addition, the switching region TrA in each pixel region P is connected to the gate line (not shown) and a gate electrode 108 is formed.

In addition, the gate insulating layer 115 may be formed as an inorganic insulating material, for example, silicon oxide (SiO ₂ ) or silicon nitride (SiNx), on the entire surface of the first substrate 110 over the gate line and the gate electrode 108. Formed.

In addition, an ohmic contact layer of impurity amorphous silicon is spaced apart from the active layer 120a of pure amorphous silicon and the upper portion of the active layer in correspondence with the gate electrode 108 in the switching region TrA on the gate insulating layer 115. A semiconductor layer 120 formed of 120b) is formed, and source and drain electrodes 133 and 136 are spaced apart from each other and contact the ohmic contact layer, respectively. In this case, the active layer 120a is exposed between the source and drain electrodes 133 and 136 spaced apart from each other.

The gate electrode 108, the gate insulating layer 115, the semiconductor layer 120, and the source and drain electrodes 133 and 136 sequentially stacked in the switching region TrA form a thin film transistor Tr.

In addition, a data line 130 defining a pixel region P intersecting the gate line (not shown) may extend in a second direction on the gate insulating layer 115, and a source electrode of the thin film transistor Tr may be formed. 133 is formed and connected.

In this case, a dummy pattern 121 formed of the first and second semiconductor patterns 121a and 121b is formed of the same material forming the active layer 120a and the ohmic contact layer 120b below the data line 130. Although shown, this is an example of the manufacturing process features, the dummy pattern 121 may be omitted.

In the drawing, the thin film transistor Tr includes an active layer 120a made of amorphous silicon and a semiconductor layer 120 of the ohmic contact layer 120b. Although a type is shown as an example, a semiconductor layer made of polysilicon is provided so as to be in contact with and spaced apart from the polysilicon semiconductor layer, the gate insulating film, the gate electrode, the interlayer insulating film, and the semiconductor layer of the polysilicon. And a top gate type having a structure in which drain electrodes are sequentially stacked.

When the top gate type thin film transistor is provided, a gate wiring (not shown) is provided on the gate insulating film on which the gate electrode is formed, and the data wiring is provided on the interlayer insulating film.

Next, a passivation layer 140 having a flat surface is provided on the data line 130 and the source and drain electrodes 133 and 136. In this case, the protective layer 140 is provided with a drain contact hole 143 exposing the drain electrode 136 of the thin film transistor Tr for each pixel region P. FIG.

In addition, a first electrode formed of a transparent conductive material on the passivation layer 140 in contact with the drain electrode 136 of the thin film transistor Tr through the drain contact hole 143 in each pixel region P. 150) is formed.

In addition, an upper portion of the passivation layer 140 exposed between the first electrode 150 and the first electrode 150, that is, a boundary of each pixel region P, that is, a gate line (not shown) and a data line 130. The buffer pattern 152 is formed to overlap the edge of the first electrode 150.

A quantum rod layer 155 including a plurality of quantum rods 156 of FIG. 2 is provided on the first electrode 150 in each pixel region P surrounded by the buffer pattern 152. In this case, the quantum rod layer 155 may be provided with a quantum rod (156 of FIG. 2) having cores (157 of FIG. 2) having different sizes for each pixel region P emitting red, green, and blue light. Alternatively, a quantum rod (156 of FIG. 2) having a core of the same size (157 of FIG. 2) may be provided.

In addition, the plurality of quantum rods 156 of FIG. 2 may be arranged in one direction on the entire surface of the display area of the first substrate 110.

In this case, the degree to which the long axis of the quantum rod (156 in FIG. 2) is well arranged in one direction, that is, the degree of alignment may be determined by measuring polarization ratio.

The degree of polarization of the quantum rod layer 155 may be determined by irradiating horizontal or vertically polarized light toward the quantum rod layer 155 and then measuring the amount of light passing through the analyzer plate.

When the intensity of light from the light source is defined as I, light with only horizontal component I _h and light with only vertical component I _v , the alignment process is not normally performed when directionality of the quantum rod is not provided. If not, the polarization ratio PR is

PR = (I _h -I _v ) / (I _h + I _v )

.

At this time, when the quantum rod layer 155 is arranged in one direction, that is, in the horizontal or vertical direction by the progress of the alignment process, the polarization ratios PR _h and PR _v in the horizontal and vertical directions are defined as follows.

PR _h = I _h / (I _h + I _v ),

PR _v = I _v / (I _h + I _v )

Therefore, in the quantum rod layer, well aligned in one direction means that the polarization ratio PR _h in the horizontal direction or the polarization ratio PR _v in the vertical direction is larger than 0.5 and smaller than 1, that is, 0.5 <PR _h or PR _v. It means to satisfy <1.

On the other hand, when the quantum rods 156 of FIG. 2 having different sizes of cores 157 of FIG. 2 are provided for pixel regions P representing red, green, and blue colors, the quantum rods 156 of FIG. As described above, the fluorescence wavelength is different depending on the size of the core (157 of FIG. 2), and the smaller the size of the core (157 of FIG. 2), the shorter the fluorescent wavelength is, and the larger the size, the longer the fluorescent wavelength is. Generate.

Therefore, in this case, the quantum rod layer 155a having the largest core size is formed to correspond to the pixel region P that should be red, and the pixel region P that should be green and blue is sequentially formed. A quantum rod layer 155b having a quantum rod (156 of FIG. 2) having a size smaller than that of the core (157 of FIG. 2) of the quantum rod (156 of FIG. 2) provided in the pixel area P representing red color; 155c) is formed.

Meanwhile, in the drawing, the quantum rod layer 155 is separately formed for each pixel region P, but as an example, FIGS. 5A and 5B (quantum rod light emitting display according to various modifications of the embodiment of the present invention). As shown in the cross-sectional view of the device), the quantum rod layer 155 may be formed in front of the display area in which the plurality of pixel areas P is provided, and in this case, the quantum rod layer 155 is provided at the boundary of each pixel area P. The buffer pattern 152 is omitted.

The second substrate 170 is provided to correspond to the first substrate 110 having such a configuration, wherein the second substrate 170 is made of glass as a transparent insulating substrate like the first substrate 110. It may be made of a plastic material having a flexible property or made, or may be a sheet or a film made of a polymer material.

The black matrix 173 is formed on the inner surface of the second substrate 170 so as to cover the boundary of the pixel region P and the portion where the thin film transistor Tr is formed.

The black matrix 173 must be provided to prevent light leakage when the quantum rod layer 155 is formed on the front of the display area (see FIGS. 5A and 5B), and the quantum rod layer 155 is formed on the front surface of the display area. If separated separately for each pixel region P (see FIGS. 4 and 5C), it may be omitted.

Meanwhile, in the exemplary embodiment of the present invention, only the black matrix 173 is provided on the inner surface of the second substrate 170, but the quantum rod layer 155 has the same size for each pixel region P. FIG. In the case of a quantum rod (156 of FIG. 2) having a core having a core (157 of FIG. 2), as shown in FIG. 5C (a cross-sectional view of a quantum rod light emitting display device according to another modified example of the embodiment of the present invention). Likewise, red, green, and blue color filter patterns 175a and 175b are sequentially repeated in three neighboring pixel areas P corresponding to the area surrounded by the black matrix 173 to realize full color. , 175c may be provided with a color filter layer 155 corresponding thereto.

Although not shown in the drawings, an overcoat layer (not shown) may be provided on the entire surface of the second substrate 170 above the black matrix 173 and the color filter layer.

As illustrated in FIG. 4, cores having different sizes for each pixel region P in which the quantum rod layer 155 provided in the first substrate 110 should show red, green, and blue colors (FIG. 2). When the quantum rod (156 of FIG. 2) having 157 of FIG. 2 is provided, a color filter layer (not shown) provided on the second substrate 170 may be provided or omitted for more excellent color reproduction. .

On the other hand, the backlight unit 180 for supplying light to the quantum rod layer 155 is provided on the lower surface of the quantum rod panel 102 having such a configuration, more precisely, on the outer surface of the first substrate 110.

In this case, the backlight unit 180 includes a light source 182, a reflecting plate 185, a light guide plate 187 mounted on the reflecting plate 185, and a plurality of optical sheets 190 positioned thereon. It is composed.

In this case, the light source 182 is smaller than 450 nm, that is, light of a short wavelength, for example, blue visible light or UV light, which is a characteristic of the present invention, a cold cathode fluorescent lamp (CCFL) and an external electrode fluorescent lamp (EEFL) It may be made of one selected from a fluorescent lamp or a light emitting diode (LED) including, and the drawing shows an example consisting of a fluorescent lamp.

The light source 182 is located on one side of the light guide plate 187 to face the light incident part of the light guide plate 187. When the light source 182 is a fluorescent lamp, the outside is guided by a lamp guide 183. have.

Meanwhile, the light guide plate 187 evenly spreads the light incident from the light source 182 to the inside of the light guide plate 187 while propagating the light incident from the light source 182 into the light guide plate 187. To provide.

In this case, the light guide plate 187 may include a pattern (not shown) of a specific shape on the rear surface to supply a uniform surface light source to the quantum rod panel 102.

In this case, a pattern of a specific shape (not shown) is various, such as an elliptical pattern, a polygonal pattern, a hologram pattern, etc. to guide light incident into the light guide plate 187. The pattern may be formed on the lower surface of the light guide plate 187 by a printing method or an injection method.

In addition, the reflective plate 185 is positioned on the rear surface of the light guide plate 187 to improve the brightness of the light by reflecting the light passing through the rear surface of the light guide plate 187 toward the quantum rod panel 102.

The optical sheet 190 provided on the light guide plate 187 includes a diffusion sheet 188 and at least one light collecting sheet 189.

On the other hand, the backlight unit 180 having such a configuration has a light source 182 is provided on the side of the light guide plate 187 and the edge type type for injecting a surface light source into the quantum rod panel 102 by the light guide plate 187. Although being shown as an example, the backlight unit 180 may be a direct type.

In the case of the direct type backlight unit (not shown), although not shown in the drawing, a plurality of light sources are disposed at a predetermined interval as a plurality of light sources, or a driving substrate for an LED in which a plurality of LEDs is disposed is provided. A diffusion plate is provided in place of the light guide plate, and a plurality of optical sheets are provided on the diffusion plate.

Meanwhile, in the quantum load light emitting display device 101 according to an exemplary embodiment of the present invention, the backlight unit 180 is disposed between the quantum load panel 102 having the above-described configuration and the backlight unit 180 as the most characteristic components. The first light recycling sheet 197 is provided to transmit the light emitted from the light emitted from the quantum rod layer 155 and to reflect the light emitted from the quantum rod layer 155. The second light recycling part is disposed on the quantum rod panel 102. The sheet 198 is provided.

In this case, the first and second light recycling sheets 197 and 198 are two or more materials having different refractive indices, for example, silicon oxide (SiO ₂ ) and titanium oxide (TiO _2). ) And tin oxide (SnO ₂ ) is provided with a selective transmissive reflective layer (not shown), characterized in that the two or more materials are alternately stacked at least one or more times to form a laminated structure of three or more layers.

In this case, the first and second light recycling sheets 197 and 198 may be formed by varying the number of layers of material layers made of two or more materials having different thicknesses and refractive indices of the selective transmissive reflective layer (not shown). A reference numeral 197 transmits light of a short wavelength and reflects light of a long wavelength, and the second light recycling sheet 198 transmits light of a long wavelength and reflects light of a short wavelength.

In this case, the reference for dividing the long wavelength and the short wavelength is from 430nm to 450nm, which is the wavelength range of the blue visible light, so the light of the long wavelength becomes the light of the wavelength band having a value larger than the 450nm, and the light of the short wavelength is the light of the wavelength band having a value smaller than 430nm. Becomes

 In the quantum rod light emitting display device 101 according to an exemplary embodiment of the present invention, the first optical recycling sheet 197 transmits light having a short wavelength band of 430 nm or less generated from the backlight unit 180, and transmits the quantum. Light efficiency, that is, power applied by recycling the light emitted from the quantum rod layer 155 by reflecting visible light having a wavelength band larger than 450 nm fluorescence from the quantum rod layer 155 provided in the load panel 102. It is characterized by having the effect of improving the brightness characteristics generated contrast.

That is, the first optical recycling sheet 197 does not reflect light emitted from the backlight unit 180 and thus does not affect the luminance characteristic at all, and receives the light emitted from the backlight unit 180 and quantum loads. By only reflecting the fluorescent light emitted from the layer 155 toward the quantum rod panel 102 where the quantum rod layer 155 is located, the light efficiency can be further improved.

In addition, since the second optical recycling sheet 198 has a property opposite to that of the first optical recycling sheet 197, the second optical recycling sheet 198 has a long wavelength band of 450 nm or more that is fluoresced from the quantum rod layer 155. The light is transmitted through the backlight unit 180, and the light having the short wavelength band of 430 nm or less generated by the backlight unit 180 is reflected in the direction in which the quantum rod layer 155 is positioned, thereby improving light efficiency by recycling light having a short wavelength.

The quantum rod layer 155 may absorb all of the short wavelength light generated from the backlight unit 180 and may not be fluorescence with light in the visible wavelength range.

6A and 6B (the comparative example shows only the backlight unit and the quantum rod layer in the quantum rod light emitting display device not including the optical recycling sheet, and shows the light traveling direction together). As shown, the short wavelength light from the backlight unit 280 is partially transmitted through the quantum rod layer 255, and since the light is not light in the visible region of light for full color implementation, It can be a factor to reduce the color reproduction rate.

In addition, the short wavelength light emitted from the backlight unit 280 is incident and absorbed by the quantum rod layer 255. The quantum rod layer 255 that absorbs light having the short wavelength band fluoresces. The light fluorescence at 255 proceeds to the upper and lower directions based on the quantum rod layer 255, and the light traveling to the lower portion of the quantum rod layer 255 is lost and disappears, thereby reducing the light efficiency. Can be.

Accordingly, in order to solve such a problem, the quantum rod light emitting display device 101 according to the present invention includes first and second optical recycling sheets 197 and 198 as illustrated in FIG. 4.

That is, in the quantum rod light emitting display device 101 according to the present invention, the light having the short wavelength passing through the quantum rod panel 102 that may affect the display quality among the light of the short wavelength band emitted from the backlight unit 180 is the second light. It is possible to improve the full color display quality by being blocked by the light recycling sheet 198.

At the same time, the light reflected by the second optical recycling sheet 198 toward the quantum rod panel 102 is re-entered into the quantum rod layer 155 provided in the quantum rod panel 102, thereby allowing the quantum rod layer The amount of light in the short wavelength band incident on 155 is increased.

This has the effect of improving the brightness of the light emitted from the light source of the backlight unit 180, even if the brightness is reduced by the short wavelength of light reflected by the second light recycling sheet 198, the second light recycling sheet 198 Since it has the same level of brightness characteristics as a quantum rod light emitting display without a light source, power consumption for driving a light source can be reduced.

Furthermore, the quantum rod light emitting display device 101 according to the embodiment of the present invention further includes a first optical recycling sheet 197, which is the quantum rod layer 155 of the fluorescent light emitted from the quantum rod layer 155. By reflecting the light toward the bottom of the quantum rod layer 155 to proceed to the upper direction of the recycling it is possible to further improve the brightness characteristics, it can further reduce the power consumption.

The present invention is not limited to the above-described embodiments, and various changes and modifications may be made without departing from the spirit of the present invention.

101: quantum rod light emitting display device 102: quantum rod panel
110: first substrate 108: gate electrode
115: gate insulating film 120: semiconductor layer
120a: active layer 120b: ohmic contact layer
121: dummy pattern 121a, 121b: first and second dummy patterns
130: data wiring 133: source electrode
136: drain electrode 140: protective layer
143: drain contact hole 150: first electrode
152: buffer pattern 155: quantum load layer
155a, 155b, and 155c: Quantum rod layers that fluoresce red, green, and blue, respectively
160: second electrode 170: second substrate
173: black matrix 180: backlight unit
182: light source 183: lamp guide
185: reflector 187: light guide plate
188: diffusion sheet 188: light collecting sheet
190: Optical sheet 197: First optical recycling sheet
198: second optical recycling sheet P: pixel region
Tr: Thin Film Transistor TrA: Switching Area

Claims (22)

A quantum rod panel including first and second substrates facing each other and a quantum rod layer interposed between the first and second substrates and having a plurality of quantum rods;
A backlight unit provided under the quantum load panel;
An optical recycling sheet disposed between at least one of the quantum rod panel and the backlight unit and an upper portion of the quantum rod panel, and configured to selectively reflect and selectively transmit light
Quantum rod light emitting display comprising a.
The method of claim 1,
And the backlight unit generates blue or ultra violet (UV) light having a short wavelength of 430 nm or less.
The method of claim 2,
The optical recycling sheet is divided into first and second optical recycling sheets, wherein the first optical recycling sheet is positioned between the quantum rod panel and the backlight unit, and the second optical recycling sheet is positioned above the quantum rod panel. A quantum rod light emitting display device.
The method of claim 3, wherein
The first optical recycling sheet has a characteristic of transmitting light having a short wavelength band of 430 nm or less and reflecting visible light having a wavelength band larger than 450 nm that is fluoresced from the quantum rod layer.
The method of claim 4, wherein
The second optical recycling sheet has a characteristic of transmitting visible light having a long wavelength band of 450 nm or more and reflecting light having a wavelength band smaller than 430 nm.
The method of claim 3, wherein
The first and second optical recycling sheets are laminated on a polymer film having a transparent and flexible property such that two or more materials having different refractive indices are alternated at least one or more times to form a laminated structure of three or more layers. A quantum rod light emitting display device having a transmissive reflective layer.
The method according to claim 6,
And wherein the selective transmissive reflective layer is formed of at least two materials of silicon oxide (SiO ₂ ), titanium oxide (TiO ₂ ), and tin oxide (SnO ₂ ).
The method of claim 7, wherein
The quantum rod light emitting display device of claim 1, wherein the first and second light recycling sheets have different numbers of layers of material layers made of two or more materials having different thicknesses and refractive indices of the selective transmissive reflective layer.
The method of claim 1,
The first substrate is provided with first, second, and third pixel areas representing red, green, and blue,
The quantum rod layer includes quantum rods having different sizes for each of the first, second, and third pixel regions.
The method of claim 9,
The second substrate is provided with a red, green, and blue color filter pattern corresponding to the first, second, and third pixel areas.
The method of claim 1,
The first substrate includes first, second, and third pixel areas representing red, green, and blue, and the quantum rod layer includes quantum rods having the same size in each pixel area.
The second substrate is provided with a red, green, and blue color filter pattern corresponding to the first, second, and third pixel areas.
The method according to any one of claims 9 to 11,
And the quantum rod layer is formed separately on each of the pixel regions on the first substrate, or is formed in front of a display region displaying an image.
The method of claim 1,
A gate line and a data line crossing the first substrate and defining the pixel areas crossing each other;
And a thin film transistor connected to the gate line and the data line, wherein the first electrode is connected to a drain electrode of the thin film transistor.
The method of claim 1,
And a plurality of quantum rods provided in the quantum rod layer are arranged in one direction.
15. The method of claim 14,
To say that the plurality of quantum rods are arranged in one direction,
When the polarization ratio PR _h in the horizontal direction and the polarization ratio PR _v in the vertical direction are defined as PR _h = I _h / (I _h + I _v ) and PR _v = I _v / (I _h + I _v ), Quantum rod light emission characterized in that it means that the polarization ratio PR _{h in the} horizontal direction or the polarization ratio PR _v in the vertical direction has a value greater than 0.5 and less than 1, that is, satisfying 0.5 <PR _h (or PR _v ) <1 Display.
The method of claim 1,
The quantum rod,
Or only core
Or a core and a shell surrounding the core,
The shell has a form having a short axis and a long axis, wherein the ratio of the short axis to the long axis is 1: 1.1 to 1:30.
17. The method of claim 16,
The quantum rod has a shape of any one of sphere, ellipsoid, polyhedron, rod shape,
The shell is a quantum rod light emitting display, characterized in that the cut surface cut in the axial direction of the quantum rod has any one of a circle, an ellipse, a polygonal shape.
17. The method of claim 16,
And the shell forms a single layer or a multilayer structure.
The method of claim 18,
And the shell is made of an alloy, an oxide-based material, or an impurity doped material.
17. The method of claim 16,
The core is a quantum rod light emitting display device, characterized in that consisting of a semiconductor, an alloy, or a mixed material of II-VI, III-V, III-VI, VI-IV, IV of the periodic table.
21. The method of claim 20,
The core of the quantum rod is made of any one of CdSe, CdS, CdTe, ZnO, ZnSe, ZnS, ZnTe, HgSe, HgTe, CdZnSe or a mixture of two or more materials when the core of the quantum rod is made of II-VI group,
In the case of the III-V group, InP, InN, GaN, InSb, InAsP, InGaAs, GaAs, GaP, GaSb, AlP, AlN, AlAs, AlSb, CdSeTe, ZnCdSe, or a mixture of two or more materials It consists of
In the case of the group VI-IV, the quantum rod light emitting display device comprising any one of PbSe, PbTe, PbS, PbSnTe, and Tl ₂ SnTe ₅ or a mixture of two or more materials.
3. The method according to claim 1 or 2,
The backlight unit includes:
An edge type backlight unit comprising a reflector plate, a light guide plate positioned on the reflector plate, a light source positioned on the side of the light guide plate, and a plurality of optical sheets positioned on the guided upper portion, or a reflector plate, a light source positioned on the reflector plate, And a direct type backlight unit including a diffuser plate positioned above the light source and a plurality of optical sheets positioned above the diffuser plate.

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