KR20130059221A - Quantum rod luminescent display device - Google Patents

Abstract

PURPOSE: A quantum rod luminescent display is provided to implement a driving of low power consumption by improving a transmittance by including only quantum rod layer which is arranged between a first electrode and a second electrode in one direction. CONSTITUTION: A quantum rod layer(155) is formed in the upper part of a first electrode(150) and includes multiple quantum rods(156) which are arranged in a surface of a first substrate(110) in one direction in parallel or includes multiple quantum rods which are arranged to be perpendicular to the surface. A second electrode(160) is formed in the upper part of the quantum rod layer. A second substrate(170) faces the first substrate. A backlight unit(180) is equipped in the outer side surface of the first substrate.

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 having an improved lifetime of low voltage high efficiency.

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 the transmission efficiency is very small. There are many difficulties in implementing low power consumption required for the product.

Therefore, in recent years, a new flat panel display device capable of solving the problems of low transmittance and high power consumption of such a liquid crystal display device is required.

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.

Such an organic electroluminescent display 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, the 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 of light emitted, and in particular, the blue light emitting material has a relatively small life time, which is less than the life of a conventional display device. It is occurring.

In addition, referring to FIG. 2 (an enlarged view of the organic light emitting layer and the light emitting auxiliary layer formed above and below the organic light emitting device in general organic light emitting device), holes and electrons of the organic light emitting layer 50 In order to increase the probability of recombination, a plurality of light emitting auxiliary layers, for example, a hole injection layer 52, a hole transport layer 54, an electron transport layer 56, and an electron injection layer 58, may be formed on the lower and upper portions of the organic light emitting layer 50. The light emitting layer 60 is further formed of five thin films. It takes a lot of process time to form such multi-layered auxiliary light emitting layer (52, 54, 56, 58), it is also a factor that increases the material cost and finally increase the manufacturing cost.

Therefore, there is still a need for a flat panel display device having a high transmittance, low power consumption, low manufacturing cost, and a lifespan similar to that of a liquid crystal display device.

The present invention has been made to solve the above problems, does not require a polarizing plate and a plurality of optical film has a large transmission efficiency and low power consumption can be driven, do not require a multi-layered thin film for light emission It is an object of the present invention to provide a display device which is also inexpensive and has a lifespan on the order of a liquid crystal display device.

A quantum rod light emitting display device according to an embodiment of the present invention comprises: a first substrate on which a plurality of pixel regions are defined; A first electrode formed in each pixel region on the first substrate; And a plurality of quantum rods formed on the first electrode and oriented in one direction parallel to the first substrate surface, or provided with a plurality of quantum rods oriented perpendicular to the first substrate surface. A quantum rod layer; A second electrode formed on the quantum rod layer; A second substrate facing the first substrate; It includes a backlight unit provided on the outer surface of the first substrate.

In this case, the quantum rod layer is formed by patterning each pixel region, and the pixel region is divided into first, second, and third pixel regions emitting red, green, and blue light, and the quantum rod layer is formed of the first, second, A quantum rod having a different size for each of the three pixel regions may be provided, and the second substrate may be provided with a red, green, and blue color filter pattern corresponding to the first, second, and third pixel regions.

In addition, the pixel region is divided into first, second, and third pixel regions emitting red, green, and blue light, and the quantum rod layer has a quantum having the same size on the entire display area including the plurality of pixel regions, regardless of the pixel region. It is formed with a rod, and 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.

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.

And, it is said that the plurality of quantum rods are oriented in one direction parallel to the first substrate surface,

The first reference line and the polarization ratio PR _h in the horizontal direction and the polarization ratio PR _v in the vertical direction are respectively PR _h = I _h / (I _h +) based on the reference line in the first direction as a reference on the first substrate surface. I _v ), PR _v = I _v / (I _h + I _v ), the horizontal polarization ratio PR _h or the vertical polarization ratio PR _v has a value greater than 0.5 and less than 1, Characterized by 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 core of the quantum rod is any one of a sphere, an ellipsoid, a polyhedron, a rod shape, the shell is a cut surface cut in the uniaxial direction of the quantum rod is any one of a circle, ellipse, polygonal shape It is characterized by forming a form.

In addition, the shell is characterized in that a single layer or a multi-layer structure, 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 of the periodic table, the core of the quantum rod is group II-VI In the case of consisting of CdSe, CdS, CdTe, ZnO, ZnSe, ZnS, ZnTe, HgSe, HgTe, CdZnSe or a mixture of two or more materials, In the case of the III-V group, InP, InN Made of any one of GaN, InSb, InAsP, InGaAs, GaAs, GaP, GaSb, AlP, AlN, AlAs, AlSb, CdSeTe, ZnCdSe, or a mixture of two or more materials, and made of Group VI-IV. , PbSe, PbTe, PbS, PbSnTe, Tl _{2 It} is made of one of SnTe ₅ or is characterized by consisting of a material in which two or more materials are mixed.

The backlight unit may generate blue or ultraviolet (UV) light having a short wavelength of 430 nm or less, and the backlight unit may include a reflector, a light guide plate positioned on the reflector, and a light source positioned on a side of the light guide plate. And an edge type backlight unit composed of a plurality of optical sheets positioned on the light guide portion, or a reflector plate, a light source positioned on the reflector plate, a diffuser plate positioned on the light source, and an upper portion of the diffuser plate. It is a direct type backlight unit composed of a plurality of optical sheets.

According to the present invention, only a quantum rod layer arranged in one direction is provided between the first electrode and the second electrode to improve transmittance compared to the liquid crystal display, thereby enabling low power consumption, and further, a display device having a longer life compared to the organic light emitting diode. Has the effect of providing.

In addition, since the fluorescence efficiency is high even if a separate light emitting auxiliary layer is not formed above and below the quantum rod layer, even if the light emitting auxiliary layer is omitted or the number of the light emitting auxiliary layer is formed, the number of the light emitting auxiliary layers can be reduced. Process time can be shortened compared to the device, and manufacturing cost can be reduced.

1 is a schematic cross-sectional view of a general liquid crystal display device;
FIG. 2 is an enlarged view of an organic light emitting layer and a light emission auxiliary layer formed above and below an organic light emitting device. FIG.
3 shows a general configuration of a quantum rod.
4 is a diagram showing the shape of the quantum rod and the states of electrons and electrons before and after applying an electric field.
5 is a cross-sectional view of a quantum rod light emitting device according to a first embodiment of the present invention.
6 is a cross-sectional view of a quantum rod light emitting device according to a second embodiment of the present invention.
FIG. 7 is a view briefly illustrating only a first substrate and a quantum rod in the quantum rod light emitting device according to the first embodiment of the present invention; FIG.
FIG. 8 is a cross-sectional view schematically illustrating only a first substrate and a quantum rod in a quantum rod light emitting display device in which a quantum rod is disposed to have a tilt angle greater than 0 degrees with a first substrate surface as a comparative example.
9A is a cross-sectional view of a quantum rod light emitting display device according to a first modification of the first and second embodiments of the present invention.
9B is a sectional view of a quantum rod light emitting display device according to a second modification of the first and second embodiments of the present invention;
10 is an enlarged view of a quantum rod layer periphery of a quantum rod light emitting display device according to still another modification of the first and second embodiments of the present invention;

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

First, the quantum rod constituting the quantum rod layer, which is the most characteristic configuration included in the quantum rod light emitting device according to the present invention, will be briefly described.

3 is a diagram illustrating a general form of a quantum rod.

As shown, the quantum rod 156 is composed of a core 157 that forms a center and a shell 158 that surrounds the core 157. In this case, the quantum rod 156 is shown as an example consisting of a core 157 and a shell 158 surrounding it, the shell 158 may be omitted, in this case, the quantum rod is a core ( 157) alone.

The core 157 may be formed in any one of a sphere, an ellipsoid, a polyhedron, and a rod shape. In the drawing, the core 157 is formed as an example.

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 156 includes a shell 158 surrounding the core 157, the core 157 may have a shape of a sphere, an ellipsoid sphere, a polyhedron, and a rod, and the shell surrounding the core 157 may be formed. 158 has a rod shape having 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, which is one component of the quantum rod 156 having such a configuration, is a semiconductor, alloy, or mixture thereof of II-VI, III-V, III-VI, VI-IV, IV of the periodic table. It may be made of a material.

When the core 157 of the quantum rod 156 is made of group II-VI of the periodic table, any one material of CdSe, CdS, CdTe, ZnO, ZnSe, ZnS, ZnTe, HgSe, HgTe, CdZnSe or two or more materials It may be made of a mixed material.

When the core 157 of the quantum rod 156 is formed of III-V group of the periodic table, InP, InN, GaN, InSb, InAsP, InGaAs, GaAs, GaP, GaSb, AlP, AlN, AlAs, AlSb, The material of any one of CdSeTe, ZnCdSe or two or more materials may be mixed.

In addition, when the core 157 of the quantum rod 156 is made of group VI-IV of the periodic table, any one of PbSe, PbTe, PbS, PbSnTe, Tl ₂ SnTe ₅ , or a material in which two or more materials are mixed. Can be done.

The quantum rod 156 having a long axis-to-short ratio with such a material has a characteristic that the fluorescence wavelength varies depending on the size of the core 157 even if the core 157 is made of the same material.

That is, as the size of the core 157 decreases, fluorescence of a short wavelength is emitted, and as the size of the core 157 increases, fluorescence of a long wavelength is generated.

Therefore, the quantum rod is characterized by being able to fluoresce almost all of the desired visible light region by adjusting the size of the core 157.

The quantum rod 156 made of a material as described above is shown in FIG. 4 (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. The fluorescence amount or the amount of light emitted from the quantum rod 156 can be adjusted accordingly, so that the light emitted from the quantum rod layer formed of the quantum rod can realize a gray level.

Here, the band gap is referred to as highest occupied molecular orbital (HOMO) as the highest energy level of the valence band and lower unoccupied molecular orbital (LUMO) as the lowest energy level of the conduction band. This is the energy difference between the HOMO level and the LUMO level.

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

 The cross-sectional structure of the quantum rod light emitting device according to the embodiment of the present invention using the quantum rod having the above-described characteristics will be briefly described.

Hereinafter, the quantum rod light emitting device according to the present invention, which serves as a display device by having a quantum rod having the above-described characteristics, will be described.

5 and 6 are cross-sectional views of the quantum rod light emitting diodes according to the first and second exemplary embodiments of the present invention, respectively, showing three neighboring pixel regions, wherein only one pixel region P is a thin film transistor that is a switching element. (Tr) is shown. 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. In this case, in the case of the first and second embodiments of the present invention, only the arrangement directions of the plurality of quantum rods 156 provided in the quantum rod layer 155 are different, and other components have the same configuration. The first embodiment will be described mainly, and the first and second embodiments will be described only with respect to portions having differentiation points.

As illustrated, the quantum rod light emitting device 101 according to the first exemplary embodiment of the present invention includes a first electrode 150 separately formed for each pixel region P, and a second electrode formed on the entire display region for displaying an image. And 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. The quantum rod panel 102 and the backlight unit 180 are formed.

In the quantum rod light emitting display device 101 according to the first exemplary embodiment having the above configuration, the quantum rod layer 155 absorbs the light emitted from the backlight unit 180 to internally recombine electrons and holes. To fluoresce the light.

In this case, the quantum rod light emitting display device 101 may change the voltages applied to the first and second electrodes 150 and 160 positioned below and above the quantum rod layer 155, respectively. By varying the intensity of the electric field between the quantum rod layer 155 to adjust the recombination rate of electrons and holes in each of the plurality of quantum rod 156 to form a gray level, the quantum rod layer ( Since the size of the quantum rod 156 is different for each pixel area P emitting red, green, and blue colors, 155 may generate red, green, and blue colors, and thus display a full-color image.

First, in the quantum rod light emitting display device 101 according to an embodiment of the present invention having the above configuration, a first substrate including the first and second electrodes 150 and 160 and the quantum rod layer 155 may be provided. The configuration of 110 will be described.

On the first substrate 110 made of a transparent insulating substrate, for example, a transparent glass substrate or a plastic substrate having flexible properties, a metal material having low resistance characteristics, such as aluminum (Al), aluminum alloy (AlNd), and copper One or more materials selected from (Cu), copper alloy, molybdenum (Mo), and molybdenum alloy (MoTi) are formed, and a gate wiring (not shown) extending in the first direction is formed.

In addition, a gate electrode 108 is formed in the switching region TrA in each pixel region P on the first substrate 110 and connected to the gate wiring (not shown).

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

The gate electrode 108, the gate insulating layer 115, the semiconductor layer 120, the source electrode 133, and the drain electrode sequentially stacked on the switching region TrA included in each pixel region P may be formed. 136 forms 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 characteristics of the manufacturing process, 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 an example of forming a bottom gate type is shown, a semiconductor layer made of polysilicon includes a semiconductor layer made of polysilicon, a gate insulating film, a gate electrode, and a semiconductor layer contact hole exposing the semiconductor layer. The interlayer insulating layer and the source and drain electrodes contacting and spaced apart from each other in contact with the semiconductor layer of polysilicon through the semiconductor layer contact hole may be formed in a top gate type having a stacked structure.

When the top gate type thin film transistor having the above-described structure is provided, the 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 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 having cores (157 of FIG. 3) having different sizes for each pixel region P emitting red, green, and blue light, or Quantum rods 156 having cores of the same size (157 of FIG. 3) may be provided.

When the quantum rod layer 155 is provided as a quantum rod 156 having cores having the same size (157 of FIG. 3) in the entire display area, the second substrate 170 may be provided for each pixel area P. FIG. A color filter layer (not shown) having a form in which red, green, and blue color filter patterns are sequentially repeated is provided.

On the other hand, the most characteristic configuration of the quantum rod light emitting display device 101 according to the first and second embodiments of the present invention, in the case of the first embodiment, the quantum rod layer 155 has a plurality of The long axis of the quantum rod 156 is disposed parallel to the surface of the first substrate 110 on the front surface of the display area of the first substrate 110 so that the major axis thereof is oriented in one direction. In this case, the plurality of quantum rods 156 may have a long axis arranged in a state perpendicular to the surface of the first substrate 110.

The degree to which the long axis of the quantum rod 156 is well arranged in one direction, that is, the degree of alignment may be determined by measuring a polarization ratio. That is, the polarization ratio of the quantum rod layer 155 may be known by measuring horizontal or vertical polarized light toward the quantum rod layer 155 and then measuring the amount of light passing through the detector plate (not shown).

When the intensity of light emitted from a light source (not shown) is defined as I, light having only a horizontal component I _h , and light having only a vertical component I _v , typically when the direction of the quantum rod 156 is not provided , The polarization ratio PR is

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

At this time, the long axis of each of the plurality of quantum rod 156 in the quantum rod layer 155 is arranged in one direction, that is, parallel to the surface of the first substrate 110 in a state that is horizontally arranged on the surface of the first substrate 110. When arranged in the horizontal or vertical direction with respect to the virtual reference axis, the polarization ratios PR _h and PR _v in the horizontal and vertical directions are defined as follows, respectively.

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

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

Therefore, in the quantum rod layer 155, the plurality of quantum rods 156 are well aligned in one direction, such that a polarization ratio PR _h in the horizontal direction or a polarization ratio PR _v in the vertical direction is larger than 0.5 and smaller than 1. That is, to satisfy 0.5 <PR _h or PR _v <1.

When the plurality of quantum rods 156 are arranged horizontally with respect to the surface of the first substrate 110 in the quantum rod layer 155 as in the first embodiment, the long axis may be arranged in one direction. Or, such that the long axis is disposed perpendicular to the surface of the first substrate 110 as in the second embodiment, absorbs the light emitted from the backlight unit 180 more efficiently, thereby allowing a greater amount of fluorescence to be transmitted and luminance. This is to improve the characteristics and further to realize high power consumption and low power consumption.

In more detail, as shown in FIG. 7 (a diagram schematically showing only the first substrate and the quantum rod in the quantum rod light emitting device according to the first embodiment of the present invention), the quantum rod layer (see FIG. 5). In the case of the first embodiment in which a plurality of quantum rods 156 provided in the 155 are disposed parallel to the surface of the first substrate 110 and arranged in one direction, the quantum rods 156 may be disposed in the first substrate ( Projection on the plane 110 will have the largest area.

On the other hand, Fig. 8 (a cross-sectional view schematically showing only the first substrate and the quantum rod in the quantum rod light emitting display device according to the comparative example in which the quantum rod is arranged to have a tilt angle greater than 0 degree with the first substrate surface as a comparative example) For reference, the quantum rod 256 disposed to have a tilt angle θ greater than 0 degrees with the surface of the first substrate 210 may have an area projected on the first substrate surface 210 as shown in FIG. 7. It can be seen that it has a smaller area than the quantum rod light emitting device (101 of FIG. 5) according to the first embodiment of the present invention disposed in parallel to the first substrate surface 110.

Therefore, as shown in FIG. 5, when light emitted from the backlight unit 180 passes through the first substrate 110 and is incident into the quantum rod layer 155, the light is incident on each quantum rod 156. Since the amount of light is maximized, the absorption rate of light for each quantum rod 156 is maximized, so that the fluorescence of each quantum rod 156 may be maximized, thereby improving transmission and luminance characteristics.

In addition, when the quantum rod 156 is disposed to be parallel to the surface of the first substrate 110 such that the area of the quantum rod 156 is maximized when projected onto the first substrate 110, the recombination of electrons and holes is performed. The rate can also be improved.

On the other hand, compared with a quantum dot light emitting display using quantum dots as another comparative example, when the core size is the same due to the characteristics of the quantum rod 156, the area receiving light is larger than the quantum dots having a spherical shape, and As in the first embodiment of the present invention, the quantum rod 156 is disposed to be parallel to the surface of the first substrate 110 in order to further maximize the area for receiving light, and thus the recombination rate of holes and electrons is higher than that of the quantum dots. It can be seen that a significant increase.

Further, it can be seen that the recombination rate of holes and electrons is significantly increased than in Comparative Example (see FIG. 8), which is not parallel to the surface of the first substrate 110 and has a predetermined angle, that is, a tilt angle larger than 0 degrees. have.

In the quantum rod light emitting display device (101 of FIG. 5) and the quantum dot light emitting display device (not shown) which are comparative examples, recombination of holes and electrons does not proceed in the quantum rod layer 155 itself, but each quantum rod 156. Since the light proceeds inside the quantum dot (not shown), light must be recombined with holes and electrons in response to light incident to each quantum rod 156.

Accordingly, the quantum rod 156 has a much better recombination rate between holes and electrons compared to a quantum dot (not shown) having a spherical shape, and even if the quantum rod 156 having the same size is parallel to the first substrate 110. It can be seen that the first embodiment of the present invention, which is arranged in one direction and has a long axis, has an excellent effect in terms of recombination rate.

The high recombination rate of holes and electrons will be apparent that the luminance characteristic is improved since the fluorescence efficiency is increased.

Meanwhile, referring to FIG. 6, in the case of the quantum rod light emitting device 101 according to the second embodiment of the present invention, the quantum rod 156 provided in the quantum rod layer 155 may face the first substrate 110. It is characterized in that it is arranged to have a state perpendicular to the, and even in such a configuration it is possible to improve the luminance characteristics by maximizing the light absorption.

When the quantum rods 156 are arranged to be perpendicular to the surface of the first substrate 110, the density of the quantum rods 156 is the largest per unit area, and the mobility in the long axis direction of the quantum rods 156 is greater than the mobility in the short axis direction. Big.

Thus, when the long axis is vertically arranged with respect to the surface of the first substrate 110 such that the plurality of quantum rods 156 have a large density per unit area as in the second embodiment of the present invention, the long axis having excellent mobility characteristics Since light is incident in the direction, the recombination time between electrons and holes is faster, thereby improving the recombination rate per unit time, thereby improving the luminance characteristic, and a relatively large number of quantum rods can be arranged per unit area. Can be improved.

Meanwhile, referring to FIGS. 5 and 6, the plurality of quantum rods 156 are disposed in one direction parallel to the first substrate 110 in the quantum rod layer 155 or the first substrate 110. The vertical alignment is possible by a voltage application method, an alignment method using an alignment layer, an alignment method using a self aligned monomer, or an alignment method using a reactive mesogen material. In this case, the alignment method is mentioned as an example, and the quantum rod 156 may be oriented in one direction by various alignment methods in addition to the four alignment methods mentioned above.

On the other hand, when the quantum rod 156 having cores (157 of FIG. 3) having different sizes for each pixel region P representing red, green, and blue is provided, the quantum rod 156 may have the core (FIG. 3). 157) is characterized in that the fluorescence wavelength is different depending on the size, the smaller the size of the core (157 of FIG. 3) emits a shorter wavelength of fluorescence, the larger the size of the fluorescence of a longer wavelength is generated.

Accordingly, in this case, the quantum rod layer 155a having the largest core (157 in FIG. 3) size (diameter) should be formed to correspond to the pixel region P that should exhibit red color, and should show green and blue colors. For the pixel region P, the quantum rod (156 in FIG. 3) having a smaller size than the core (157 in FIG. 3) of the quantum rod (156 in FIG. 3) provided in the pixel region P showing red in sequence. It is characterized in that the quantum rod layer (155b, 155c) having a formed.

Meanwhile, in the first and second embodiments of the present invention shown in FIGS. 5 and 6, the quantum rod layer 155 is separately formed for each pixel region P, but as an example, FIG. 9A ( As shown in a cross-sectional view of a quantum rod light emitting display device according to a first modification of the first and second embodiments of the present invention, the quantum rod layer 155 includes a display area in which a plurality of pixel areas P are provided. The buffer pattern 152 provided at the boundary of each pixel region P may be omitted.

5 and 6, in the first and second embodiments of the present invention, a second substrate 170 is provided to correspond to the first substrate 110 having such a configuration. The substrate 170 may be made of a glass material or a plastic material having flexible properties as a transparent insulating substrate like the first substrate 110, 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 FIG. 9A), and the quantum rod layer 155 is disposed in each pixel region ( If separated by P) may be omitted.

Meanwhile, in the first and second embodiments of the present invention, although only the black matrix 173 is provided on the inner surface of the second substrate 170, the quantum rod layer 155 is formed in each pixel area P. When the quantum rod (156 of FIG. 3) having a core (157 of FIG. 3) having the same size for each of them, FIG. 9B (quantum rod light emission according to the second modification of the first and second embodiments of the present invention) As shown in the cross-sectional view of the display device, red and green are sequentially repeated in three neighboring pixel areas P corresponding to the area surrounded by the black matrix 173 to realize full color. The color filter layer 155 may correspond to the blue color filter patterns 175a, 175b, and 175c.

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 155.

As shown in FIGS. 5 and 6, cores having different sizes for each pixel region P in which the quantum rod layer 155 of the first substrate 110 should show red, green, and blue colors are shown. When the quantum rod 156 having (157 of FIG. 2) is provided, the color filter layer (not shown) provided on the second substrate 170 may be omitted for high luminance characteristics, or may be omitted in FIG. 9B. As shown in the second modified example, it may be provided for more excellent color reproduction.

Meanwhile, in the first and second embodiments and modifications thereof, only the quantum rod layer 155 is provided between the first electrode 150 and the second electrode 160, but FIG. Referring to an enlarged view of a quantum rod light emitting display device according to still another modification of the first and second embodiments of the present invention, the first electrode 150 and the quantum rod layer ( A hole injection layer 157 may be provided as a fluorescent auxiliary layer between the 155, and an electron injection layer 158 is further provided as a fluorescent auxiliary layer between the quantum rod layer 155 and the second electrode 160. May be

Next, referring to FIGS. 5 and 6, a backlight unit that supplies light to the quantum rod layer 155 on the lower side of the quantum rod panel 102 having such a configuration, more precisely, on the outer surface of the first substrate 110. 180 is provided.

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 at one side of the light guide plate 187 so as 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 (not shown). It is becoming.

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 a direct type backlight unit (not shown), although not shown in the drawings, 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 are disposed is provided on the reflection plate. A diffusion plate is provided in place of the light guide plate, and a plurality of optical sheets are provided on the diffusion plate.

Since the quantum rod light emitting display device 101 according to the first and second embodiments or modified examples of the present invention having such a configuration does not require a polarizing plate that lowers the luminance characteristic, the luminance characteristic is reduced by providing the polarizing plate. By providing a brighter light source to improve the lowered luminance characteristics, there is an advantage of having a high luminance characteristic and a low power consumption characteristic compared to a liquid crystal display device in which power consumption is increased.

Furthermore, the quantum rod 156 provided inside the quantum rod layer 155 has a configuration in which its long axis is oriented in one direction while being disposed parallel to the surface of the first substrate 110 or the quantum rod 156 per unit area. Since it has a configuration arranged perpendicular to the surface of the first substrate 110 to maximize the density of the unit at the same time and maximize the recombination rate per unit time, the light emitted from the backlight unit 180 is better absorbed and fluorescent, Compared to the quantum rod light emitting display devices in which the quantum rods are arranged in an orderly or disordered manner, the brightness characteristics and the low power consumption characteristics are improved.

In addition, the quantum rod display device 101 according to the first and second embodiments and modified examples of the present invention does not require a polarizing plate or the like, and furthermore, the color filter layer can be omitted. Since the number of parts can be reduced, there is an effect of reducing the manufacturing cost.

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 P: pixel area
Tr: thin film transistor TrA: switching region

Claims (15)

A first substrate on which a plurality of pixel regions are defined;
A first electrode formed in each pixel region on the first substrate;
And a plurality of quantum rods formed on the first electrode and oriented in one direction parallel to the first substrate surface, or provided with a plurality of quantum rods oriented perpendicular to the first substrate surface. A quantum rod layer;
A second electrode formed on the quantum rod layer;
A second substrate facing the first substrate;
Back light unit provided on the outer surface of the first substrate
Quantum rod light emitting display device comprising a.
The method of claim 1,
The quantum rod layer is formed by patterning each pixel region, and the pixel region is divided into first, second, and third pixel regions emitting red, green, and blue light, and the quantum rod layer is formed of the first, second, and third pixels. A quantum rod light emitting display device having a quantum rod having cores of different sizes for each region.
3. The method of claim 2,
The second substrate has a red, green, and blue color filter pattern corresponding to the first, second, and third pixel areas.
The method of claim 1,
The pixel area is divided into first, second, and third pixel areas emitting red, green, and blue light, and the quantum load layer has a same core size on the entire display area including the plurality of pixel areas, regardless of the pixel area. And a red, green, and blue color filter pattern corresponding to the first, second, and third pixel areas on the second substrate.
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 has a red, green, and blue color filter pattern corresponding to the first, second, and third pixel areas.
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,
To say that the plurality of quantum rods are oriented in one direction parallel to the first substrate surface,
The first reference line and the polarization ratio PR _h in the horizontal direction and the polarization ratio PR _v in the vertical direction are respectively PR _h = I _h / (I _h +) based on the reference line in the first direction as a reference on the first substrate surface. I _v ), PR _v = I _v / (I _h + I _v ), the horizontal polarization ratio PR _h or the vertical polarization ratio PR _v has a value greater than 0.5 and less than 1, A quantum rod light emitting display device characterized by satisfying 0.5 < PR _h (or PR _v ) <
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 short axis to long axis is 1: 1.1 to 1:30.
The method of claim 8,
The core of the quantum rod has a shape of any one of sphere, ellipsoid, polyhedron, rod shape,
The shell is a quantum rod light emitting display device, characterized in that the cut surface cut in the axial direction of the quantum rod form any one of a circle, ellipse, polygonal form.
The method of claim 9,
The shell is a quantum rod light emitting display device characterized in that a single layer or a multi-layer structure.
11. The method of claim 10,
The shell is a quantum rod light emitting display device, characterized in that the alloy (oxide), oxide-based or doped with a material doped.
The method of claim 8,
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 group on the periodic table.
13. The method of claim 12,
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
The quantum rod light emitting display device, wherein the quantum rod light emitting display device is made of any one of PbSe, PbTe, PbS, PbSnTe, Tl ₂ SnTe ₅ , or a mixture of two or more materials.
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 1,
The backlight unit includes:
An edge type backlight unit including a reflecting plate, a light guide plate positioned on the reflecting plate, a light source positioned on a side of the light guide plate, and a plurality of optical sheets positioned on the light guided portion;
Or a direct-type backlight unit comprising a reflector, a light source positioned above the reflector, a diffuser positioned above the light source, and a plurality of optical sheets positioned above the diffuser.

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