KR20170021399A - Quantum rod panel and Quantum rod display device - Google Patents

Abstract

In a quantum rod panel and a quantum rod display device according to the present invention, the use efficiency of light from a backlight unit or a quantum rod is increased because each of a pixel electrode and a common electrode includes a transparent conductive material layer and a reflective conductive material layer. Therefore, the quantum rod display device with high brightness can be provided.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a quantum rod panel and a quantum rod display device,

The present invention relates to a display device, and more particularly, to a quantum rod panel and a quantum rod display device having high luminance.

(PDP), plasma display (PDP), and plasma display devices (PDPs) have been rapidly developed in the field of display for processing and displaying a large amount of information. Various flat panel display devices such as a panel device (PDP), a field emission display device (FED), an organic light emitting diode (OLED) display device (OELD)

On the other hand, in recent years, studies have been made to use quantum rods (quantum rods) in display devices.

Quantum rods have many applications with high luminous efficiency and excellent reproducibility. Therefore, research is being conducted to apply quantum rods to display devices.

The quantum rods include nano-sized II-VI semiconductor materials, III-V semiconductor materials, or a core made of a VI-IV semiconductor material and a shell for protecting the core.

The quantum rod has a very high extinction coefficient and a high quantum yield as compared to a general dye, so that it generates strong fluorescence and can adjust the wavelength of the visible light emitted by adjusting the diameter of the quantum rod.

The quantum rod also has a characteristic of emitting linearly polarized light. That is, the quantum rod emits linearly polarized light in a direction parallel to the longitudinal direction.

In addition, when an external electric field is applied by the stark effect, electrons and holes are separated from each other and have optical characteristics to control luminescence. That is, on / off control can be performed according to application of an electric field.

When such a quantum rod is used for a display device, a display device with high luminance by high quantum efficiency is expected, but the quantum rod display device can not exhibit a desired luminance.

The present invention intends to increase the luminance of a quantum road panel and a quantum road display device.

According to an aspect of the present invention, there is provided a method for driving a quantum rod layer, comprising: forming a pixel electrode and a common electrode, each of which forms a horizontal electric field, And the thickness is made larger than the thickness of the layer of the reflective conductive material.

That is, the pixel electrode and the common electrode each include a lower layer made of a transparent conductive material and an upper layer made of a reflective conductive material, and the thickness of the lower layer is equal to or greater than the thickness of the upper layer, .

On the other hand, the pixel electrode and the common electrode each include a lower layer made of a reflective conductive material and an upper layer made of a transparent conductive material, and the thickness of the upper layer is equal to or larger than the thickness of the lower layer, .

Further, since the thickness of the quantum rod layer is equal to or smaller than the thickness of the pixel electrode and the common electrode, the off characteristics of the quantum rod display device can be improved.

In the quantum rod panel and the quantum rod display device of the present invention, since the quantum rod layer is driven by the horizontal electric field generated between the pixel electrode and the common electrode, the polarization characteristics of the quantum rod panel and the quantum rod display device are improved.

Further, in the quantum rod panel and the quantum rod display device of the present invention, the pixel electrode and the common electrode include a transparent conductive material layer and a reflective conductive material layer, and the thickness of the transparent conductive material layer is equal to or greater than the thickness of the reflective conductive material layer The light efficiency and luminance of the quantum rod panel and the quantum rod display device are increased.

Further, the quantum rod layer has a thickness equal to or smaller than the thickness of the pixel electrode and the common electrode, thereby improving the off characteristics of the quantum rod panel and the quantum rod display device.

Further, since the quantum rod panel and the quantum rod display device of the present invention can omit the polarizer and the color filter layer required in the liquid crystal display device, the thickness of the quantum rod panel and the quantum rod display device can be reduced and the manufacturing cost can be reduced Effect.

In addition, since the quantum rod can be aligned without an alignment film, the manufacturing process of the quantum rod panel and the quantum rod display device is simplified, and the manufacturing cost is further reduced.

1 is a schematic cross-sectional view of a quantum rod display device according to a first embodiment of the present invention.
2 is a schematic plan view for explaining a driving principle of the quantum rod display device of the present invention.
3 is a schematic cross-sectional view of a quantum rod display device according to a second embodiment of the present invention.
4 is a graph showing off characteristics according to a thickness ratio of a quantum rod layer and an electrode.
5 is a schematic cross-sectional view of a quantum rod display device according to a third embodiment of the present invention.

The present invention provides a liquid crystal display device comprising: a first substrate and a second substrate facing each other; a pixel electrode disposed on the first substrate and including a first layer and a second layer positioned on the first layer; And a fourth layer disposed on the third layer and the third layer, the fourth layer being located on the third layer and spaced apart from the pixel electrode, and a quantum rod disposed between the pixel electrode and the common electrode. Wherein the first layer and the third layer are one of a transparent conductive material layer and a reflective conductive material layer, and the second layer and the fourth layer are layers of the transparent conductive material layer and the reflective conductive material layer Wherein the thickness of the layer of the transparent conductive material is equal to or greater than the thickness of the layer of the reflective conductive material.

In the quantum rod panel of the present invention, the thickness of the quantum rod layer may be equal to or less than the thickness of the pixel electrode and the common electrode.

In the quantum rod panel of the present invention, the long axis of the quantum rod may be arranged perpendicular to the extending direction of the pixel electrode.

The quantum rod panel of the present invention may further include a thin film transistor located on the first substrate and connected to the pixel electrode.

The quantum rod panel of the present invention may further include a protective layer covering the thin film transistor, and the lower surface of the quantum rod layer may contact the protective layer.

In the quantum rod panel of the present invention, a plurality of pixel regions may be defined on the first substrate, and may further include a lattice-shaped partition wall covering each pixel region.

In another aspect, the present invention provides a quantum rod display device including the above-described quantum rod panel and a backlight unit located under the quantum rod panel and including a UV light source.

Hereinafter, preferred embodiments according to the present invention will be described with reference to the drawings.

- First Embodiment -

1 is a schematic cross-sectional view of a quantum rod display device according to a first embodiment of the present invention.

1, the quantum rod display device 100 according to the first embodiment of the present invention includes a quantum rod panel 110 and a quantum rod panel 110 located below the quantum rod panel 110, And a backlight unit 120 for supplying light to the backlight unit 120.

The quantum rod panel 110 includes a first substrate 130 adjacent to the backlight unit 120, a pixel electrode 180 and a common electrode 182 located on the first substrate 130, A second substrate 140 facing the first substrate 130 and a quantum rod layer 150 disposed between the first and second substrates 130 and 140 and including a quantum rod 152 .

Each of the first and second substrates 130 and 140 may be a glass substrate or a plastic substrate. For example, in the case where each of the first and second substrates 130 and 140 is a flexible substrate such as polyimide, the quantum rod display device 100 of the present invention may be a display device such as a foldable, Device. ≪ / RTI >

A gate line (not shown) and a data line (not shown) are formed on the first substrate 130, and the gate line and the data line cross each other to define a pixel region (not shown).

A thin film transistor (Tr), which is a switching element, is formed in each of the pixel regions, and the pixel electrode 180 is electrically connected to the thin film transistor Tr.

The thin film transistor Tr includes a gate electrode 162 formed on the first substrate 130, a semiconductor layer 166 formed on the gate electrode 162 and overlapping the gate electrode 162, And a source electrode 172 and a drain electrode 174 that are spaced apart from each other on the semiconductor layer 166.

More specifically, the gate wiring extends along the first direction, and the gate electrode 162 is connected to the gate wiring. Although not shown, a common wiring line spaced apart from the gate wiring line may be formed on the first substrate.

Each of the gate wiring, the common wiring, and the gate electrode 162 may be made of a low resistance metal material. For example, each of the gate wiring, the common wiring, and the gate electrode 162 may be formed of any one of aluminum (Al), aluminum alloy (AlNd), molybdenum (Mo), copper (Cu) have.

A gate insulating film 164 covering the gate wiring, the common wiring, and the gate electrode 162 is formed on the first substrate 130. The gate insulating layer 164 may be formed of an inorganic insulating material such as silicon oxide or silicon nitride.

The semiconductor layer 166 is located on the gate insulating film 164 and corresponds to the gate electrode 162. The semiconductor layer 166 may be made of an oxide semiconductor material. Although not shown, an etch stopper may be formed corresponding to the center of the semiconductor layer 166.

Meanwhile, the semiconductor layer 166 may have a bilayer structure of an active layer made of pure amorphous silicon and an ohmic contact layer made of impurity amorphous silicon.

The source electrode 172 and the drain electrode 174 are spaced from each other and located on the semiconductor layer 166. Each of the source electrode 172 and the drain electrode 174 may be formed of a low resistance metal material. For example, each of the source electrode 172 and the drain electrode 174 may be formed of any one of aluminum (Al), aluminum alloy (AlNd), molybdenum (Mo), copper (Cu), and copper alloy.

The source electrode 172 is connected to the data line. That is, the thin film transistor Tr is electrically connected to the gate wiring and the data wiring.

A protective layer 176 having a drain contact hole 178 for exposing the drain electrode 174 is formed to cover the thin film transistor Tr. The passivation layer 176 may be formed of an inorganic insulating material such as silicon oxide or silicon nitride or an organic insulating material such as benzocyclobutene (BCB) or photo acryl.

The pixel electrode 180 and the common electrode 182 are located on the protective layer 176 and are spaced apart from each other. The pixel electrode 180 is connected to the drain electrode 174 through a drain contact hole 178 formed in the passivation layer 176 and the common electrode 182 is connected to the gate insulating layer 164 and the passivation layer 174. [ (Not shown) formed through the first contact hole 176. [

Each of the pixel electrode 180 and the common electrode 182 may be formed of a reflective conductive material such as aluminum (Al), aluminum alloy (AlNd), molybdenum (Mo), copper (Cu), or copper alloy.

On the protective layer 176, barrier ribs 190 for partitioning the respective pixel regions are formed. That is, the barrier rib 190 may have a lattice shape with a pixel region. The quantum rod 152 is separated for each pixel region by the barrier 190 to realize red, green, and blue in each pixel region. The partition 190 may be omitted.

The quantum rod layer 150 is disposed on the passivation layer 176 and is separated into pixel regions by the barrier 190. That is, the quantum rod layer 150 is located in contact with the pixel electrode 180 and the common electrode 182. The lower surface of the quantum rod layer 150 is in contact with the protective layer 176.

The quantum rod layer 150 includes a plurality of quantum rods 152 that may include at least one of a II-VI semiconductor material, a III-V semiconductor material, or a VI- .

For example, the quantum rod 152 may be made of a material selected from the group consisting of CdSe, CdS, CdTe, ZnSe, ZnS, ZnTe, HgSe, HgTe, CdZnSe (III-V semiconductor material), PbSe, PbTe, PbS (VI-IV group semiconductor material), GaP, GaSb, AlP, AlN, AlAs, AlSb, or a mixture of two or more thereof.

A planarization layer 192 is formed on the barrier rib 190 and the quantum rod layer 150. A step that can be generated by the partition 190 and the quantum rod layer 150 is planarized by the planarization layer 192. The planarization layer 192 may be omitted.

The second substrate 140 is positioned on the planarization layer 192 and may be attached to the planarization layer 192 through an adhesive layer (not shown).

The backlight unit 120 includes a UV light source (not shown). That is, since the quantum rod 152 absorbs UV light and emits visible light, the backlight unit 120 includes a UV light source and supplies UV to the quantum rod panel 110.

Although not shown, the backlight unit 120 may be a direct type in which a plurality of UV light sources are arranged under the quantum rod panel 110 to supply UV directly to the quantum rod panel 110. The direct-type backlight unit 120 may further include a reflector positioned under the UV light source, and an optical sheet positioned between the UV light source and the quantum rod panel 110.

Alternatively, the backlight unit 120 may be an edge type including a light guide plate positioned under the quantum rod panel 110, and the UV light source may be disposed on a side surface of the light guide plate. The edge type backlight unit 120 may further include a reflection plate positioned below the light guide plate and an optical sheet positioned between the light guide plate and the quantum rod panel 110.

In the present invention, the pixel electrode 180 and the common electrode 182 are positioned on the first substrate 130 and form a horizontal electric field.

2, which is a schematic plan view for explaining the principle of operation of the quantum rod display device of the present invention, the quantum rod 152 has an electric field whose long axis is formed between the pixel electrode 180 and the common electrode 182 (E). In other words, the long axis of the quantum rod 152 is arranged perpendicular to the extending direction of the pixel electrode 180 and the common electrode 182.

When UV is supplied from the backlight unit 120 to the quantum rod layer 150 including the quantum rod 152 arranged perpendicular to the extending direction of the pixel electrode 180 and the common electrode 182, A visible ray linearly polarized in the longitudinal direction of the rod 152 is emitted from the quantum rod 152. [ On the other hand, when the electric field E is applied to the quantum rod layer 150, the light emission of the quantum rod 152 is stopped. Therefore, by using the pixel electrode 180 and the common electrode 182 of the horizontal electric field system, the polarization characteristics of the quantum rod panel and the quantum rod display device are improved and the display device can be turned on and off.

When an electric field E is generated by applying a voltage to the pixel electrode 180 and the common electrode 182 while the quantum rod 152 is randomly dispersed, the quantum rod 152 has a long axis And are arranged parallel to the electric field direction. The quantum rod 152 is cured so that the long axis of the quantum rod 152 is parallel to the direction of the electric field E formed between the pixel electrode 180 and the common electrode 182 Lt; / RTI > That is, the alignment layer and the aligning process required in the conventional liquid crystal display device can be omitted.

In addition, since the quantum rod 152 can emit red, green, and blue visible rays, the color filter required for color implementation in conventional liquid crystal display devices can be omitted.

On the other hand, since the intensity of the electric field is weak at the pixel electrode and the common electrode, the quantum rod located above the pixel electrode and the common electrode has poor alignment and the off characteristic of the quantum rod display device decreases. Therefore, light leakage can be generated from the quantum rod display device.

However, in the quantum rod display device 100 according to the first embodiment of the present invention, since the pixel electrode 180 and the common electrode 182 are made of an opaque metal material, the pixel electrode 180 and the common electrode 182 are blocked.

Therefore, the problem of light leakage of the quantum rod display device can be reduced.

However, the UV from the backlight unit 120 is not efficiently supplied to the quantum rod 152, so that the luminance of the quantum rod display device 100 is lowered.

1, a portion of the UV (L1) from the backlight unit 120 is supplied to the quantum rod 152 through a space between the pixel electrode 180 and the common electrode 182, while the remaining UV (L2) And is blocked by the opaque pixel electrode 180 and the common electrode 182.

Therefore, there arises a problem of the light efficiency and the luminance lowering of the quantum rod display device 100.

- Second Embodiment -

3 is a schematic cross-sectional view of a quantum rod display device according to a second embodiment of the present invention.

3, the quantum rod display device 200 according to the second embodiment of the present invention includes a quantum rod panel 210 and a quantum rod panel 210 located below the quantum rod panel 210, And a backlight unit 220 for supplying light to the backlight unit 220.

The quantum rod panel 210 includes a first substrate 230 adjacent to the backlight unit 220, a pixel electrode 280 and a common electrode 282 located on the first substrate 230, A second substrate 240 facing the first substrate 230 and a quantum rod layer 250 disposed between the first and second substrates 230 and 240 and including a quantum rod 252 .

Each of the first and second substrates 230 and 240 may be a glass substrate or a plastic substrate. For example, in the case where each of the first and second substrates 230 and 240 is a flexible substrate such as polyimide, the quantum rod display device 200 of the present invention may be a display device such as a foldable display, Device. ≪ / RTI >

A gate line (not shown) and a data line (not shown) are formed on the first substrate 230, and the gate line and the data line cross each other to define a pixel region (not shown).

A thin film transistor (Tr), which is a switching element, is formed in each of the pixel regions, and the pixel electrode 280 is electrically connected to the thin film transistor Tr.

The thin film transistor Tr includes a gate electrode 262 formed on the first substrate 230, a semiconductor layer 266 formed on the gate electrode 262 and overlapping the gate electrode 262, And a source electrode 272 and a drain electrode 274 that are spaced apart from each other on the semiconductor layer 266.

A passivation layer 276 having a drain contact hole 278 exposing the drain electrode 274 is formed on the thin film transistor Tr and the pixel electrode 280 and the common electrode 282 are formed on the protective layer 274. [ (276). The pixel electrode 280 is connected to the drain electrode 274 through the drain contact hole 278.

The pixel electrode 280 includes a first layer 280a made of a transparent conductive material and a second layer 280b disposed on the first layer 280a and made of a reflective conductive material, 280b. The common electrode 282 includes a third layer 282a made of a transparent conductive material and a fourth layer 282b disposed on the third layer 282a and made of a reflective conductive material. Layer 282b.

In FIG. 3, the pixel electrode 280 and the common electrode 282 are shown to have a double-layer structure, but the present invention is not limited thereto. For example, when layers of different transparent conductive materials are stacked and reflective conductive materials are stacked, the pixel electrode 280 and the common electrode 282 may have a triple layer structure, or different reflective conductive materials may be stacked on the transparent conductive material layer The pixel electrode 280 and the common electrode 282 may have a triple layer structure. In addition, the transparent electrode layers 280 and the common electrode 282 may have a four-layer structure, because different transparent conductive material layers are stacked and different reflective material layers are stacked.

In FIG. 3, one pixel electrode 280 and one common electrode 282 are arranged apart from each other, but the present invention is not limited thereto. For example, the plurality of pixel electrodes 280 and the plurality of common electrodes 282 may be alternately arranged and spaced from each other.

For example, the transparent conductive material may be indium-tin-oxide (ITO) or indium-zinc-oxide (IZO) ), An aluminum alloy (AlNd), molybdenum (Mo), copper (Cu), or a copper alloy.

The first layer 280a has a first thickness t1 and the second layer 280b has a second thickness t2 that is less than or equal to the first thickness t1. The third layer 282a has a third thickness t3 and the fourth layer 282b has a fourth thickness t4 that is less than or equal to the third thickness t3.

The first thickness t1 may be equal to the third thickness t3 and the second thickness t2 may be equal to the fourth thickness t4. The fifth thickness t5 of the pixel electrode 280 may be equal to the sixth thickness t6 of the common electrode 282. [ Alternatively, the first thickness t1 may be different from the third thickness t3, or the second thickness t2 may be different from the fourth thickness t4, t5 and the sixth thickness t6 of the common electrode 282 may be different.

On the protective layer 276, barrier ribs 290 for partitioning the respective pixel regions are formed. That is, the barrier ribs 290 may have a lattice shape with a pixel area. The quantum rod 252 may be separated for each pixel region by the barrier ribs 290 to realize red, green, and blue in each pixel region. The partition 290 may be omitted.

The quantum rod layer 250 including the quantum rods 252 is located on the protective layer 276 and separated by pixel regions by the barrier ribs 290. That is, the quantum rod layer 250 is disposed between and in contact with the pixel electrode 280 and the common electrode 282. The lower surface of the quantum rod layer 250 is in contact with the protective layer 276.

The quantum rod layer 250 has a seventh thickness t7 that is equal to or less than a fifth thickness t5 of the pixel electrode 280 and a sixth thickness t6 of the common electrode 282. [

The quantum rods 252 may include at least one of a II-VI semiconductor material, a III-V semiconductor material, or a VI-IV semiconductor material.

For example, the quantum rod 252 may be formed of a material selected from the group consisting of CdSe, CdS, CdTe, ZnSe, ZnS, ZnTe, HgSe, HgTe, CdZnSe (II-VI semiconductor materials), InP, InN, GaN, InSb, InAsP, InGaAs, GaAs (III-V semiconductor material), PbSe, PbTe, PbS (VI-IV group semiconductor material), GaP, GaSb, AlP, AlN, AlAs, AlSb, or a mixture of two or more thereof.

A planarization layer 292 is formed on the barrier ribs 290 and the quantum rod layer 250. The level difference that can be generated by the barrier ribs 290 and the quantum rod layer 250 is planarized by the planarization layer 292. The planarization layer 292 may be omitted.

The second substrate 240 is positioned on the planarization layer 292 and may be attached to the planarization layer 292 through an adhesive layer (not shown).

The backlight unit 220 includes a UV light source (not shown). That is, since the quantum rod 252 absorbs UV light and emits visible light, the backlight unit 220 includes a UV light source and supplies UV to the quantum rod panel 210.

Although not shown, the backlight unit 220 may be a direct type in which a plurality of UV light sources are arranged under the quantum rod panel 210 to directly supply UV to the quantum rod panel 210. The direct-type backlight unit 220 may further include a reflector positioned under the UV light source, and an optical sheet positioned between the UV light source and the quantum rod panel 210.

Alternatively, the backlight unit 220 may be of an edge type including a light guide plate positioned below the quantum rod panel 210, and the UV light source may be positioned on a side surface of the light guide plate. The edge type backlight unit 220 may further include a reflector positioned under the light guide plate and an optical sheet positioned between the light guide plate and the quantum rod panel 210.

The quantum rod layer 250 is driven by a horizontal electric field formed between the pixel electrode 280 and the common electrode 282. The quantum rod layer 250 receives the UV light from the backlight unit 220, Release.

In the quantum rod display device 200 according to the second embodiment of the present invention, the quantum rod 250 is disposed between the first and second layers 280a and 280b of the pixel electrode 280 and the third And the light L incident on the pixel electrode 280 and the common electrode 282 of the light from the backlight unit 220 is transmitted through the fourth layer 282a, And is reflected by the second and fourth layers 280b and 282b made of a reflective conductive material after passing through the first and third layers 280a and 282a made of a transparent conductive material. Since the reflected light L is supplied to the quantum rod 252 located between the pixel electrode 280 and the common electrode 282, the light loss generated in the quantum rod display device 100 according to the first embodiment Can be prevented.

Thus, the light efficiency and luminance of the quantum rod display device 200 are improved.

Since the thicknesses t1 and t3 of the first and third layers 280a and 282a made of a transparent conductive material are relatively large in the pixel electrode 280 and the common electrode 282, Sufficient space is provided so that the light L reflected by the second and fourth layers 280b and 282b can be supplied to the quantum rod 252. [

That is, generally, since the pixel electrode and the common electrode require a low resistance, when the pixel electrode and the common electrode have a laminate structure of the transparent conductive material layer and the low resistance metal material layer having the reflection characteristic, And has a thickness larger than that of the transparent conductive material layer.

However, in the present invention, the UV from the backlight unit 220 is reflected by the pixel electrode 280 and the second and fourth layers 280b and 282b, which are upper layers of the common electrode 282, to the quantum rod 252 The thicknesses t1 and t3 of the first and third layers 280a and 282a made of a transparent conductive material are set such that the thicknesses of the second and fourth layers 280b and 282b made of a reflective conductive material t2, t4).

In the quantum rod display device 200 according to the second embodiment of the present invention, the quantum rod layer 250 has the same thickness as the thickness t5, t6 of the pixel electrode 280 and the common electrode 282 Or smaller than the thickness t7 so that the entire quantum rod 252 is driven by an electric field generated directly between the pixel electrode 280 and the common electrode 282. [ Therefore, the polarization characteristic and the off characteristic in the quantum rod display device 200 are improved.

Experimental Example 1

In the above-described quantum rod display device, the brightness was measured by varying the thickness and thickness of the pixel electrode and the common electrode, and the results are shown in Table 1.

In Comparative Example 1, the pixel electrode and the common electrode had a single metal layer structure of aluminum, and in Experimental Examples 1 to 3, the thickness of the ITO layer as the lower layer was changed.

ITO layer thickness
[nm] Metal layer thickness
[nm] Luminance
[au] Luminance increase rate
[%] Comparative Example 1 - 150 28.0 - Experimental Example 1 50 100 29.3 4.6 Experimental Example 2 75 75 33.4 19 Experimental Example 3 100 50 35.2 25.7

As shown in Table 1, when compared with the quantum rod display device of Comparative Example 1 in which the pixel electrode and the common electrode have a single-layer structure, as in the second embodiment of the present invention, the pixel electrode and the common electrode are made of a transparent conductive material The luminance of the quantum rod display device of Experimental Examples 1 to 3 including the first layer (lower layer) of ITO and the second layer (upper layer) of aluminum as the reflective conductive material is improved.

Further, in the quantum rod display devices of Experimental Examples 2 and 3, in which the first layer of the pixel electrode and the common electrode has a thickness equal to or larger than that of the second layer, the brightness is greatly increased.

Experimental Example 2

The off ratio was measured by changing the thickness ratio of the quantum rod layer and the electrodes (pixel electrode and common electrode) in the above-described quantum rod display device. The measurement results are shown in FIG. 4, Respectively.

Thickness ratio (QR / electrode) Off ratio (%) 0.55 83.1 0.93 83.0 0.99 82.9 1.04 82.1 1.10 80.0 1.40 75.0 1.88 71.4 3.00 65.2

As shown in FIG. 4 and Table 2, when the thickness of the quantum rod layer is equal to or smaller than the thickness of the electrode, it has a high off characteristic.

- Third Embodiment -

5 is a schematic cross-sectional view of a quantum rod display device according to a third embodiment of the present invention.

5, the quantum rod display device 300 according to the third embodiment of the present invention includes a quantum rod panel 310 and a quantum rod panel 310 located below the quantum rod panel 310, And a backlight unit 320 for supplying light to the backlight unit 320.

The quantum rod panel 310 includes a first substrate 330 adjacent to the backlight unit 320, a pixel electrode 380 and a common electrode 382 located on the first substrate 330, A second substrate 340 facing the first substrate 330 and a quantum rod layer 350 disposed between the first and second substrates 330 and 340 and including a quantum rod 352 .

Each of the first and second substrates 330 and 340 may be a glass substrate or a plastic substrate. For example, in the case where each of the first and second substrates 330 and 340 is a flexible substrate such as polyimide, the quantum rod display device 300 of the present invention may be a display device such as a foldable display, Device. ≪ / RTI >

A gate wiring (not shown) and a data wiring (not shown) are formed on the first substrate 330. The gate wiring and the data wiring cross each other to define a pixel region (not shown).

A thin film transistor (Tr), which is a switching element, is formed in each of the pixel regions, and the pixel electrode 380 is electrically connected to the thin film transistor Tr.

The thin film transistor Tr includes a gate electrode 362 formed on the first substrate 330, a semiconductor layer 366 formed on the gate electrode 362 and overlapping the gate electrode 362, And a source electrode 372 and a drain electrode 374 that are spaced apart from each other on the semiconductor layer 366.

A protective layer 376 having a drain contact hole 378 exposing the drain electrode 374 is formed on the thin film transistor Tr and the pixel electrode 380 and the common electrode 382 are formed on the protective layer 370. [ (376). The pixel electrode 380 is connected to the drain electrode 374 through the drain contact hole 378.

The pixel electrode 380 includes a first layer 380a made of a reflective conductive material and a second layer 380b disposed on the first layer 380a and made of a transparent conductive material 380b. The common electrode 382 includes a third layer 382a made of a reflective conductive material and a fourth layer 382b disposed on the third layer 382a and made of a transparent conductive material. Layer 382b.

Although the pixel electrode 380 and the common electrode 382 are shown in FIG. 5 as having a double-layer structure, the present invention is not limited thereto. For example, when layers of different reflective conductive materials are stacked and a transparent conductive material is stacked, the pixel electrode 380 and the common electrode 382 may have a triple layer structure, or different transparent conductive material layers may be formed on the reflective conductive material layer The pixel electrode 380 and the common electrode 382 can have a triple layer structure. In addition, the reflective electrode layer 380 and the common electrode 382 may have a four-layer structure, in which different reflective conductive material layers are stacked and different transparent material layers are further stacked.

In FIG. 5, one pixel electrode 380 and one common electrode 382 are arranged apart from each other, but the present invention is not limited thereto. For example, the plurality of pixel electrodes 380 and the plurality of common electrodes 382 may be alternately arranged and spaced from each other.

For example, the reflective conductive material may be aluminum (Al), aluminum alloy (AlNd), molybdenum (Mo), copper (Cu), or copper alloy, and the transparent conductive material may be an indium-tin -oxide, ITO) or indium-zinc-oxide (IZO).

The first layer 380a has a first thickness t1 and the second layer 380b has a second thickness t2 that is equal to or greater than the first thickness t1. The third layer 382a has a third thickness t3 and the fourth layer 382b has a fourth thickness t4 that is equal to or greater than the third thickness t3.

The first thickness t1 may be equal to the third thickness t3 and the second thickness t2 may be equal to the fourth thickness t4. The fifth thickness t5 of the pixel electrode 380 may be equal to the sixth thickness t6 of the common electrode 382. [ Alternatively, the first thickness t1 may be different from the third thickness t3, the second thickness t2 may be different from the fourth thickness t4, and the fifth thickness t3 may be different from the third thickness t3, t5 and the sixth thickness t6 of the common electrode 382 may be different.

On the protective layer 376, barrier ribs 390 for partitioning the respective pixel regions are formed. That is, the barrier ribs 390 may have a lattice shape with a pixel area. The quantum rod 352 may be separated for each pixel region by the partition 390 to realize red, green, and blue in each pixel region. The partition 390 may be omitted.

The quantum rod layer 350 including the quantum rods 352 is located on the protective layer 376 and separated by pixel regions by the barrier walls 390. That is, the quantum rod layer 350 is disposed between and in contact with the pixel electrode 380 and the common electrode 282. The lower surface of the quantum rod layer 350 is in contact with the protective layer 376.

The quantum rod layer 350 has a seventh thickness t7 that is equal to or less than a fifth thickness t5 of the pixel electrode 380 and a sixth thickness t6 of the common electrode 382. [

The quantum rods 352 may include at least one of a II-VI semiconductor material, a III-V semiconductor material, or a VI-IV semiconductor material.

For example, the quantum rods 352 may be made of a material selected from the group consisting of CdSe, CdS, CdTe, ZnSe, ZnS, ZnTe, HgSe, HgTe, CdZnSe (II-VI semiconductor materials), InP, InN, GaN, InSb, InAsP, InGaAs, GaAs (III-V semiconductor material), PbSe, PbTe, PbS (VI-IV group semiconductor material), GaP, GaSb, AlP, AlN, AlAs, AlSb, or a mixture of two or more thereof.

A planarization layer 392 is formed on the partition 390 and the quantum rod layer 350. The step that can be generated by the partition 390 and the quantum rod layer 350 is planarized by the planarization layer 392. [ The planarization layer 392 may be omitted.

The second substrate 340 is positioned on the planarization layer 392 and may be attached to the planarization layer 392 through an adhesive layer (not shown).

The backlight unit 320 includes a UV light source (not shown). That is, since the quantum rod 352 absorbs UV light and emits visible light, the backlight unit 320 includes a UV light source and supplies UV to the quantum rod panel 310.

Although not shown, the backlight unit 320 may be a direct type in which a plurality of UV light sources are arranged under the quantum rod panel 310 to supply UV directly to the quantum rod panel 310. The direct-type backlight unit 320 may further include a reflector positioned under the UV light source, and an optical sheet positioned between the UV light source and the quantum rod panel 310.

Alternatively, the backlight unit 320 may be an edge type including a light guide plate disposed under the quantum rod panel 310, and the UV light source may be positioned on a side surface of the light guide plate. The edge type backlight unit 320 may further include a reflector positioned below the light guide plate and an optical sheet positioned between the light guide plate and the quantum rod panel 310.

The quantum rod layer 350 is driven by a horizontal electric field formed between the pixel electrode 380 and the common electrode 382. The quantum rod layer 350 receives the UV light from the backlight unit 320 and emits the linearly polarized visible light Release.

In the quantum rod display device 300 according to the third embodiment of the present invention, the quantum rod 350 is disposed between the first and second layers 380a and 380b of the pixel electrode 380 and the third And some of the light emitted from the quantum rod 352 is driven by a horizontal electric field formed between the pixel electrode 380 and the fourth layer 382a and 382b, A first layer 380a made of a reflective conductive material is formed as a lower layer of the pixel electrode 380 and the common electrode 382 after passing through a second layer 380b and a fourth layer 382b made of a transparent conductive material as an upper layer, And the third layer 382a and is directed to the second substrate 340. [

That is, the loss of light emitted from the quantum rod 352 is minimized, and the light efficiency and luminance of the quantum rod display device 300 are improved.

Since the thicknesses t2 and t4 of the second and fourth layers 380b and 382b made of a transparent conductive material are relatively large in the pixel electrode 380 and the common electrode 382, The loss of emitted light is minimized.

As described above, since the pixel electrode and the common electrode require a low resistance, when the pixel electrode and the common electrode have a laminated structure of a low-resistance metal material layer and a transparent conductive material layer having reflection characteristics, And has a thickness larger than that of the transparent conductive material layer.

However, in the present invention, after the light L emitted from the quantum rod 352 passes through the pixel electrode 380 and the second and fourth layers 380b and 382b, which are upper layers of the common electrode 382, The first and third layers 380a and 382a which are the lower layers of the common electrode 380 and the common electrode 382 must be reflected on the upper surfaces of the second and fourth layers 380b and 382b made of a transparent conductive material. The thicknesses t2 and t4 are equal to or larger than the thicknesses t1 and t3 of the first and third layers 380a and 382a made of a reflective conductive material.

In the quantum rod display device 300 according to the third embodiment of the present invention, the quantum rod layer 350 has the same thickness as the thickness t5, t6 of the pixel electrode 380 and the common electrode 382 Or smaller than the thickness t7, the entire quantum rod 352 is driven by an electric field generated directly between the pixel electrode 380 and the common electrode 382. [ Therefore, the polarization characteristic and off-characteristic in the quantum rod display device 300 are improved.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the appended claims. It can be understood that

100, 200, 300: Quantum load display device
110, 210, 310: display panel 120, 220, 320: backlight unit
130, 140, 230, 240, 330, 340:
150, 250, 350: Quantum rod layer 152, 252, 352: Quantum rod
180, 280, 380: pixel electrodes 182, 282, 382:

Claims (7)

A first substrate and a second substrate facing each other;
A pixel electrode disposed on the first substrate and including a first layer and a second layer disposed on the first layer;
A common electrode disposed on the first substrate and spaced apart from the pixel electrode and including a third layer and a fourth layer disposed on the third layer;
And a quantum rod layer including a quantum rod positioned between the pixel electrode and the common electrode,
Wherein the first layer and the third layer are one of a transparent conductive material layer and a reflective conductive material layer and the second layer and the fourth layer are another one of the transparent conductive material layer and the reflective conductive material layer, Wherein the thickness of the layer of transparent conductive material is equal to or greater than the thickness of the layer of reflective conductive material.
The method according to claim 1,
Wherein a thickness of the quantum rod layer is equal to or less than a thickness of the pixel electrode and the common electrode.
The method according to claim 1,
And the long axis of the quantum rod is arranged perpendicular to the extending direction of the pixel electrode.
The method according to claim 1,
And a thin film transistor located on the first substrate and connected to the pixel electrode.
5. The method of claim 4,
Further comprising a protective layer covering the thin film transistor, the lower surface of the quantum rod layer being in contact with the protective layer.
The method according to claim 1,
And a plurality of pixel regions are defined on the first substrate, and further comprising a lattice-shaped partition wall covering each pixel region.
A quantum rod panel according to any one of claims 1 to 6;
A backlight unit located below the quantum road panel and including a UV light source;
And the quantum rod display device.

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