KR101800884B1 - Display Device - Google Patents

Abstract

A display device according to an embodiment of the present invention includes a substrate including first to third subpixels, a thin film transistor located in each of the first to third subpixels, an LED chip connected to each of the thin film transistors, And a protective film disposed on the thin film transistor and the resin layer.

Description

[0001]

The present invention relates to a display device, and more particularly, to a display device capable of connecting an LED chip to a thin film transistor to display an image.

2. Description of the Related Art [0002] Recently, various portable electronic devices such as mobile phones, PDAs, and notebooks have been developed, and thus a demand for a lightweight thin flat panel display device is increasing. As such flat panel display devices, a liquid crystal display (LCD), a plasma display panel (PDP) and an organic light emitting diode (OLED) have been actively studied. A liquid crystal display device in which the ease of driving means and the realization of a high image quality are easily spotlighted.

Among them, a liquid crystal display device is a light-receiving display device which can not emit light independently of an organic electroluminescent device. Therefore, the liquid crystal display device has a separate light source under the liquid crystal layer to provide light to the liquid crystal layer.

At this time, since the liquid crystal layer utilizes the polarization property of liquid crystal, a polarizing plate should be provided on the upper and lower portions of the liquid crystal layer, and a color filter is provided so as to emit red, green and blue. Accordingly, in order to drive the liquid crystal layer, the liquid crystal display has a low transmittance by various accessories, and the response time is slow due to the characteristics of the liquid crystal itself, and various optical films are required. In addition, since it can not emit light itself, there is a problem that the contrast ratio is low and the color sharpness is low.

On the other hand, in the case of the electric signboard provided in a public place, the LED chip emitting red, green and blue colors is used to show the three primary colors. However, there is a problem that it is difficult to realize a high resolution by configuring the LED chips in a dot matrix form.

The present invention provides a display device capable of improving image quality such as response speed and sharpness by displaying an image using a thin film transistor and an LED chip.

In order to achieve the above object, a display device according to an embodiment of the present invention includes a substrate including first to third sub-pixels, a thin film transistor positioned in each of the first to third sub-pixels, A resin layer covering each of the LED chips, and a protective film disposed on the thin film transistor and the resin layer.

The LED chip may emit a single color, an ultraviolet ray or a three primary colors of red, green and blue.

The LED chip may emit a single color of blue.

The resin layer located in the second sub-pixel includes a green phosphor, and the resin layer located in the third sub-pixel may include a red phosphor.

The LED chip located in the first subpixel emits red, the LED chip located in the second subpixel emits green, and the LED chip located in the third subpixel emits blue light.

The resin layer located in the first sub-pixel includes a red phosphor, the resin layer located in the second sub-pixel includes a green phosphor, and the resin layer located in the third sub-pixel includes a blue phosphor .

The LED chip may be flip chip bonded or vertically chip bonded.

The thin film transistor may include a gate electrode, a semiconductor layer, a source electrode, and a drain electrode.

And a black matrix provided on the thin film transistors.

The display device of the present invention has an advantage that the difference of the color coordinate value according to the viewing angle can be reduced and the relative luminance can be improved by forming the LED chip as the light emitting means in the thin film transistor. Further, there is an advantage that the response speed of the display device can be remarkably improved.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows a display device according to an embodiment of the present invention. Fig.
2 is a view showing a kind of an LED chip.
3 is a view showing a structure in which vertical LED chips are connected.
4 is a circuit diagram of a display apparatus according to the present invention.
5 and 6 show a display device according to an embodiment of the present invention.
7 is a graph showing a difference in color coordinate values according to a viewing angle of a display device according to an embodiment of the present invention.
8 is a graph showing a relative luminance according to a viewing angle of a display device according to an embodiment of the present invention.
FIG. 9A is a graph showing a response speed of a conventional liquid crystal display device, and FIG. 9B is a graph showing a response speed of a display device according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a view illustrating a display device according to an embodiment of the present invention. FIG. 2 is a view showing the types of LED chips, and FIG. 3 is a view illustrating a structure in which vertical LED chips are connected.

Referring to FIG. 1, a display device 10 according to an embodiment of the present invention includes a substrate 100 including first through third sub-pixels S1, S2, and S3, The LED chips 200R, 200G and 200B connected to the thin film transistors TFT and the LED chips 200R, 200G and 200B, respectively, A layer 180 and a protective layer 190 disposed on the resin layer 180 and the thin film transistor (TFT).

The substrate 100 may be made of glass, plastic, or a conductive material, and the first to third sub-pixels S1, S2, and S3 may be partitioned.

A thin film transistor (TFT) is placed on the substrate 100. The thin film transistor TFT is located in each of the first to third sub pixels S1, S2 and S3 and includes the gate electrode 110, the semiconductor layer 130, the source electrode 140a and the drain electrode 140b do.

More specifically, the gate electrode 110 is located on the substrate 100. Gate electrode 110 be formed of one selected from the group consisting of aluminum (Al), aluminum alloy (Al alloy), molybdenum (Mo), molybdenum alloy (Mo alloy), tungsten (W), tungsten silicide (WSi ₂₎ have.

A gate insulating film 120 is disposed on the gate electrode 110. The gate insulating film 120 may be formed of a silicon oxide film (SiOx), a silicon nitride film (SiNx), or a double layer thereof.

A semiconductor layer 130 is formed on the gate insulating layer 120 in a region corresponding to the gate electrode 110. The semiconductor layer 130 may be formed of amorphous silicon or polycrystalline silicon crystallized from amorphous silicon.

A source electrode 140a and a drain electrode 140b are located on the semiconductor layer 130. [ The source electrode 140a and the drain electrode 140b may be formed of one or more selected from the group consisting of aluminum (Al), aluminum alloy (Al alloy), molybdenum (Mo), molybdenum alloy (Mo alloy), and tungsten Lt; / RTI > layer.

Accordingly, a thin film transistor (TFT) including the gate electrode 110, the semiconductor layer 130, the source electrode 140a, and the drain electrode 140b is formed as described above.

A passivation film 150 is disposed on the thin film transistor TFT. The passivation film 150 may be formed of a silicon oxide film, a silicon nitride film, or a double layer thereof, similar to the gate insulating film 120 described above.

A black matrix 160 for partitioning the first to third sub-pixels S1, S2, and S3 is disposed on the passivation layer 150. [

On the other hand, LED chips 200R, 200G, and 200B are disposed on one side of the thin film transistor (TFT).

Referring to FIG. 2, the LED chips 200R, 200G, and 200B connected to the thin film transistor (TFT) may have a horizontal or vertical structure.

Fig. 2 (a) shows a horizontal type LED chip, and Fig. 2 (b) shows a vertical type LED chip. To describe this in more detail, the LED chip (a) of the horizontal structure is located on the substrate 210. Substrate 210 may be a single crystal substrate made of sapphire, spinel, silicon carbide, zinc oxide, magnesium oxide, GaN, AlGaN, AlN, NGO (NdGaO _3), LGO (LiGaO _2), LAO (LaAlO ₃₎ or the like.

The n-type semiconductor layer 211 may be positioned on the substrate 210 and the n-type semiconductor layer 211 may be formed of, for example, n-GaN. The active layer 212 may be located on the n-type semiconductor layer 211, and the active layer 212 may be formed of, for example, InGaN. The p-type semiconductor layer 213 may be located on the active layer 212 and the p-type semiconductor layer 213 may be formed of, for example, p-GaN.

The p-type electrode 214 may be positioned on the p-type semiconductor layer 213 and the p-type electrode 214 may include at least one of chromium, nickel, or gold. The n-type electrode 215 may be positioned on the n-type semiconductor layer 211 and the n-type electrode 215 may include at least one of chromium, nickel, and gold.

On the other hand, the LED chip (b) of the vertical structure has a structure in which the p-type electrode 215, the p-type semiconductor layer 213, the active layer 212, the n-type semiconductor layer 211, . ≪ / RTI >

When a voltage is applied to the p-type electrode 215 and the n-type electrode 215, such an LED chip is formed by combining holes and electrons in the active layer 212 and emitting light corresponding to a height difference (energy gap) It can be operated on the principle of releasing energy.

Referring again to FIG. 1, the LED chips 200R, 200G, and 200B may be connected to either the source electrode 140a or the drain electrode 140b of the thin film transistor TFT.

More specifically, the reflective electrode 140c is located in a region spaced apart from the thin film transistor (TFT). The reflective electrode 140c applies a voltage to the LED chips 200R, 200G, and 200B, and may be made of a material having a high reflectance. The reflective electrode 140c may be made of the same material as the source electrode 140a or the drain electrode 140c and may be formed of a metal such as aluminum Al alloy Al alloy Mol alloy Mo alloy ), And tungsten (W).

One side of the LED chips 200R, 200G and 200B may be connected to the drain electrode 140b of the thin film transistor TFT and the other side thereof may be connected to the reflective electrode 140c. At this time, the LED chips 200R, 200G, and 200B may be connected by a flip chip bonding method.

More specifically, a conductive shoulder paste 170 is placed between the p-type electrode and the n-type electrode of the LED chips 200R, 200G, and 200B, and the drain electrode 140b and the reflective electrode 140c, respectively. Here, the LED chips 200R, 200G, and 200B connected in a flip-chip bonding manner may be LED chips having a horizontal structure.

Here, the LED chips 200R, 200G, and 200B included in the first to third sub-pixels S1, S2, and S3 may emit red, green, and blue light, respectively. 1, the LED chip 200R located in the first sub-pixel S1 can emit red light, and the LED chip 200G located in the second sub-pixel S2 emits green light And the LED chip 200B located in the third sub-pixel S3 can emit blue light.

Accordingly, the first to third sub-pixels S1, S2, and S3 emit red, green, and blue primary colors to realize full color.

On the other hand, a black matrix 160 is disposed on the passivation film 150 of the thin film transistor (TFT), and each of the first to third sub pixels S1, S2, S3 partitioned by the black matrix 160 has a resin layer (180) may be filled.

The resin layer 180 protects the LED chips 200R, 200G, and 200B, and may be made of silicon or epoxy resin as a transparent material through which light can pass.

Meanwhile, when the LED chip according to the embodiment of the present invention has a vertical structure, it may be bonded to the thin film transistor TFT and the reflective electrode 140c as shown in FIG.

Referring to FIG. 3, a transparent electrode 240 is disposed on a drain electrode 140c of a thin film transistor (TFT). The vertical LED chip 200 is laterally laid on the side surface of the transparent electrode 240 so that the p-type electrode is in contact with the transparent electrode 240 and the n-type electrode is in contact with the reflective electrode 140c. The p-type electrode and the n-type electrode of the LED chip 200 may be connected to the transparent electrode 240 and the reflective electrode 140c using a shoulder paste or an eutectic bonding method.

A resin layer 180 surrounding the LED chip 200 is positioned on the LED chip 200. Accordingly, the LED chip 200 emits light according to the voltage applied from the transparent electrode 240 and the reflective electrode 140c.

Referring again to FIG. 1, a protective layer 190 is formed on the black matrix 160 and the resin layer 180 to form a display device according to an embodiment of the present invention.

The display device according to an embodiment of the present invention configured as described above can be driven as follows.

4 is a circuit diagram of a display apparatus according to the present invention.

Referring to FIG. 4, a plurality of scan lines SL are arranged in a horizontal direction, and a plurality of data lines DL are arranged in a direction perpendicular to the scan lines SL to partition a plurality of sub-pixels.

When a signal is applied from the scan line SL and a signal is applied from the data line DL, the thin film transistor TFT of the sub-pixel in which the scan line SL and the data line DL, to which the signal is applied, The LED chips 200R, 200G, and 200B are switched according to a signal to emit the LED chips 200R, 200G, and 200B.

The light intensity of each of the LED chips 200R, 200G, and 200B is controlled by the intensity of a voltage applied to each thin film transistor (TFT). Accordingly, each sub-pixel emits red, green, and blue light, thereby realizing full color.

Meanwhile, the display device according to an embodiment of the present invention may include LED chips emitting a single color or an ultraviolet ray. Hereinafter, an example in which the LED chips are flip-chip bonded will be described.

5 and 6 are views showing a display device according to an embodiment of the present invention. In the following, the same components as those in FIG. 1 described above will be described with the same reference numerals.

Referring to FIG. 5, the display device 10 according to an embodiment of the present invention may be configured such that the LED chips 200 located in the first through third sub-pixels S1, S2, and S3 emit blue single colors have.

At this time, the resin layer 180 covering the LED chips 200 may include a phosphor that exhibits a specific color. More specifically, the first sub-pixel S1 is composed of the LED chip 200 that emits blue light and the transparent resin layer 180 to emit blue light.

The second sub-pixel S2 may further include a green phosphor 240G in the resin layer 180. [ Accordingly, the second sub-pixel S2 can emit green light due to the LED chip 200 emitting blue light and the green phosphor 240G.

In addition, the third sub-pixel S3 may further include a red phosphor 240R in the resin layer 180. [ Accordingly, the third sub-pixel S3 can emit red light due to the LED chip 200 emitting blue light and the red phosphor 240R.

Accordingly, the display device 10 according to an embodiment of the present invention further includes the LED chip 200 emitting blue light and the fluorescent material of a specific color for each of the sub-pixels S1, S2, and S3, The three primary colors of blue are emitted to realize full color.

6, the display device 10 according to an exemplary embodiment of the present invention may be configured such that the LED chips 200U located in the first through third sub-pixels S1, S2, and S3 emit ultraviolet rays have.

The LED chip 200U that emits ultraviolet rays can emit ultraviolet rays in a wavelength range of 200 to 360nm using gallium aluminum nitride (AlGaN) as a semiconductor material.

At this time, the resin layer 180 covering the LED chips 200U may include a phosphor that exhibits a specific color. More specifically, the first sub-pixel S1 may further include an LED chip 200U emitting ultraviolet rays and a red phosphor 240R in a transparent resin layer 180. [ Accordingly, the first sub-pixel S1 can emit red light due to the LED chip U and the red phosphor 240R emitting ultraviolet rays.

The second sub-pixel S2 may further include a green phosphor 240G in the resin layer 180. [ Accordingly, the second sub-pixel S2 can emit green light due to the LED chip 200U and the green phosphor 240G emitting ultraviolet rays.

In addition, the third sub-pixel S3 may further include a red phosphor 240B in the resin layer 180. [ Accordingly, the third sub-pixel S3 can emit red light due to the LED chip 200U and the blue phosphor 240B emitting ultraviolet rays.

Therefore, the display device 10 according to an embodiment of the present invention further includes the LED chip 200U emitting ultraviolet rays and the fluorescent material of a specific color for each sub-pixel S1, S2, and S3, The three primary colors of blue are emitted to realize full color.

FIG. 7 is a graph showing a difference in color coordinate values according to a viewing angle of a display device according to an exemplary embodiment of the present invention, FIG. 8 is a graph illustrating relative brightness according to a viewing angle of a display device according to an exemplary embodiment of the present invention, FIG. 9A is a graph showing a response speed of a conventional liquid crystal display device, and FIG. 9B is a graph illustrating a response speed of a display device according to an embodiment of the present invention.

Referring to FIG. 7, the difference of the color coordinate values according to the viewing angle of the display device indicates that the difference of the color coordinate values according to the viewing angle is large in the conventional liquid crystal display device. However, The difference in color coordinate values is small.

Referring to FIG. 8, the relative brightness according to the viewing angle of the display device is as follows. In the case of the conventional liquid crystal display device, the relative brightness is low and the deviation is large. However, It can be seen that the overall is high and the deviation is small.

9A and 9B, when the response speeds of the display devices are compared, it is understood that the response speed of the display device of the present invention is significantly faster than the response speed of the conventional liquid crystal display device.

As described above, the display device according to an embodiment of the present invention has an advantage that the difference in the color coordinate value according to the viewing angle can be reduced and the relative brightness can be improved by forming the LED chip as the light emitting means in the thin film transistor. Further, there is an advantage that the response speed of the display device can be remarkably improved.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood that the invention may be practiced. It is therefore to be understood that the embodiments described above are to be considered in all respects only as illustrative and not restrictive. In addition, the scope of the present invention is indicated by the following claims rather than the detailed description. Also, all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

Claims (9)

A substrate including first to third sub-pixels;
Thin film transistors each including a gate electrode, a gate insulating film for insulating the gate electrode, and a source electrode and a drain electrode located on the gate insulating film, the thin film transistors being located in the first to third subpixels, respectively;
LED chips disposed adjacent to the thin film transistors;
A reflective electrode positioned on the gate insulating film;
A resin layer covering the LED chips; And
And a protective film disposed on the resin layer and the thin film transistors,
Wherein one side of the LED chips is connected to the source electrode or the drain electrode, the other side of the LED chips is connected to the reflective electrode,
Wherein the source electrode or the drain electrode and the reflective electrode are located on the same layer and contact the upper surface of the gate insulating film, respectively.
The method according to claim 1,
Wherein the LED chip emits a single color, ultraviolet light or three primary colors of red, green and blue.
3. The method of claim 2,
Wherein the LED chip emits a blue single color.
The method of claim 3,
Wherein the resin layer located in the second sub-pixel includes a green phosphor, and the resin layer located in the third sub-pixel includes a red phosphor.
3. The method of claim 2,
Wherein the LED chip located in the first sub-pixel emits red, the LED chip located in the second sub-pixel emits green, and the LED chip located in the third sub-pixel emits blue.
3. The method of claim 2,
Wherein the resin layer located in the first sub-pixel includes a red phosphor, the resin layer located in the second sub-pixel includes a green phosphor, and the resin layer located in the third sub-pixel includes a blue phosphor Display device.
The method according to claim 1,
Wherein the LED chip has a horizontal structure.
The method according to claim 1,
Wherein the thin film transistor further comprises a semiconductor layer.
The method according to claim 1,
And a black matrix provided on each of the thin film transistors.

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