KR102768123B1 - Light emitting diode(LED) display device - Google Patents

Abstract

The present application relates to a micro-LED display device, and more particularly, to a micro-LED display device having high color reproducibility with color mixing prevented.
A feature of the present invention is that the outer surface of the second semiconductor layer protruding from the concave portion of the reflective insulating film is positioned so that the silicon pattern surrounds it. Accordingly, even without positioning a separate black matrix between each subpixel of the color conversion pattern positioned above the micro-LED, light leakage at the boundary of each subpixel or light leakage caused by being incident on an adjacent subpixel can be prevented, thereby omitting the process for forming the black matrix, thereby simplifying the process and reducing the process cost. In addition, since the deletion of the black matrix can prevent some of the light emitted from the micro-LED from being absorbed by the black matrix, the light extraction efficiency of the micro-LED can also be improved.
In addition, the high temperature heat generated in the process of driving the micro-LED by the silicon pattern can be quickly dissipated to the outside, thereby preventing a decrease in efficiency due to deterioration of the micro-LED.

Description

LED display device {Light emitting diode(LED) display device}

The present application relates to a micro-LED display device, and more particularly, to a micro-LED display device having high color reproducibility with color mixing prevented.

Recently, as display devices become larger, the demand for flat display elements that occupy less space is increasing, and the technology of flat display devices such as liquid crystal display (LCD) devices or organic electroluminescent display (OLED) devices including organic light emitting diodes (OLED) devices is developing at a rapid pace.

Here, in the liquid crystal display device, a backlight unit is placed below a liquid crystal panel with polarizing plates attached to the back and front surfaces, and accordingly, only 5% or less of the light from a light source provided in the backlight unit passes through the liquid crystal panel, resulting in a disadvantage in light efficiency.

In addition, in the case of organic light emitting diode displays, although they have improved luminous efficiency compared to liquid crystal displays, they still have limitations in luminous efficiency and still have disadvantages in durability and/or lifespan of the display device.

Therefore, recently, micro-light emitting diode (LED) displays have been proposed to overcome the above problems of liquid crystal displays and/or organic light emitting diode displays.

Micro-LED displays are display devices that implement images by arranging ultra-small LEDs (μLEDs) measuring 100 micrometers (㎛) or less in size in each subpixel, and have great advantages in terms of low power consumption and miniaturization.

However, despite the advantages of such micro-LED displays over liquid crystal displays and/or organic light emitting diode displays, there is a recent trend to demand micro-LED displays with improved luminous efficiency.

The present invention is intended to solve the above-mentioned problems, and a first object of the present invention is to improve the efficiency of the micro-LED itself of a micro-LED display device, and a second object of the present invention is to provide a micro-LED display device having a large screen, high resolution, and improved light efficiency.

In order to achieve the object as described above, the present invention provides an LED display device including a substrate in which a first subpixel expressing a first color and a second subpixel expressing a second color having a larger wavelength band than the first color and arranged adjacent to the first subpixel are defined, a light emitting diode including first and second semiconductor layers and an active layer positioned between the first and second semiconductor layers and each positioned in the light emitting area of the first and second subpixels, and a silicon pattern arranged to surround a portion of an outer surface of the second semiconductor layer, corresponding to a non-light emitting area surrounding an edge of the light emitting area.

Here, the light-emitting diode includes a p-type electrode electrically connected to the first semiconductor layer, and a common electrode electrically connected to the second semiconductor layer and positioned in the non-light-emitting region, wherein the p-type electrode is electrically connected to a driving thin film transistor positioned on the substrate, the common electrode is electrically connected to a common voltage wiring positioned on the substrate, and the common electrode is positioned to extend from a side surface of the second semiconductor layer to a lower portion of the silicon pattern.

And, the common electrode is positioned above the second semiconductor layer and the silicon pattern, and further includes a common voltage wiring positioned on the substrate, wherein the silicon pattern, the common voltage wiring, and the second semiconductor layer are electrically connected to each other.

In addition, it includes a third subpixel adjacent to the second subpixel, wherein each of the light-emitting diodes of the first to third subpixels emits light of a different color, the light-emitting diodes of the first and second subpixels emit the first color, and are positioned corresponding to the light-emitting area of the second subpixel, and includes a first color conversion pattern that wavelength-converts the first color into the second color.

And, a third subpixel is disposed adjacent to the second subpixel, expressing a third color having a wavelength band larger than that of the second color, and includes a second color conversion pattern positioned corresponding to the third subpixel and wavelength-converting the first color into the third color, wherein the first color is blue light, the second color is green light, and the third color is red light.

And, the first color conversion pattern includes a quantum dot that converts the first color into the second color, the second color conversion pattern includes a quantum dot that converts the first color into the third color, and a reflective insulating film including concave portions each corresponding to the light-emitting area is positioned on the front surface of the substrate, and the light-emitting diodes are each positioned in the concave portions.

In addition, the present invention comprises the steps of forming a groove pattern on a growth substrate corresponding to a light-emitting area of each subpixel, the step of sequentially epitaxially growing a second semiconductor material layer, an active material layer and a first semiconductor material layer on the growth substrate, the step of etching the second semiconductor material layer, the active material layer and the first semiconductor material layer except for the light-emitting area on the growth substrate to form first and second semiconductor layers and an active layer respectively corresponding to the light-emitting area of each subpixel, the step of forming a p-type electrode on the first semiconductor layer, the step of forming a common electrode electrically in contact with the second semiconductor layer, the step of closely contacting a driving substrate equipped with a driving thin film transistor for each subpixel to the growth substrate so that the p-type electrode is electrically connected to a connection electrode electrically connected to a drain electrode of the driving thin film transistor, and the step of etching the growth substrate so that at least a portion of a surface of the second semiconductor layer is exposed to the outside and surrounds an outer surface of the second semiconductor layer. A method for manufacturing an LED display device is provided, including a step of forming a silicon pattern by etching a back surface.

Here, the active layer positioned in each of the subpixels emits blue light, and includes a step of forming a first color conversion pattern for converting the blue light into red light on the second semiconductor layer, corresponding to a red subpixel among the subpixels, and a step of forming a second color conversion pattern for converting the blue light into green light on the second semiconductor layer, corresponding to a green subpixel among the subpixels, and further includes a step of doping an element into the silicon pattern.

As described above, by positioning the outer surface of the second semiconductor layer protruding from the concave portion of the reflective insulating film according to the present invention so that the silicon pattern surrounds it, there is an effect of preventing light leakage from occurring at the boundary of each subpixel or light leakage occurring by being incident on an adjacent subpixel without having to position a separate black matrix between each subpixel of the color conversion pattern positioned above the micro-LED.

Through this, the process for forming a black matrix can be omitted, which can lead to the effects of simplifying the process and reducing the process cost. In addition, by deleting the black matrix, some of the light emitted from the micro-LED can be prevented from being absorbed by the black matrix, which also has the effect of improving the light extraction efficiency of the micro-LED.

In addition, since the high temperature heat generated in the process of driving the micro-LED by the silicon pattern can be quickly dissipated to the outside, there is also an effect of preventing a decrease in efficiency due to deterioration of the micro-LED.

In addition, since the common electrode can be formed using various materials, it can reduce process costs and increase process convenience, which can also have the effect of improving process efficiency.

FIG. 1 is a cross-sectional view showing three subpixels of a micro-LED display device according to a first embodiment of the present invention.
FIGS. 2A to 2L are cross-sectional views showing manufacturing steps for three subpixels of a micro-LED display device according to a first embodiment of the present invention.
FIGS. 3A to 3B are cross-sectional views showing further manufacturing steps for three subpixels of a micro-LED display device according to the first embodiment of the present invention.
FIG. 4 is a cross-sectional view showing three subpixels of a micro-LED display device according to a second embodiment of the present invention.
FIGS. 5a and 5b are cross-sectional views showing three subpixels of a micro-LED display device according to another configuration of the second embodiment of the present invention.

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

- Example 1 -

FIG. 1 is a cross-sectional view showing three subpixels of a micro-LED display device according to a first embodiment of the present invention.

Before the explanation, each sub-pixel (R-SP, G-SP, B-SP) defined on the substrate (101) is equipped with a driving and switching thin film transistor (DTr, not shown), but for the convenience of explanation and the simplicity of the drawing, the driving thin film transistor (DTr) is shown only in one sub-pixel (R-SP, G-SP, B-SP).

As described above, the micro-LED display device (100) according to the first embodiment of the present invention has a plurality of sub-pixels (R-SP, G-SP, B-SP) defined on the substrate (101), and each of the plurality of sub-pixels (R-SP, G-SP, B-SP) may be defined by a crossing structure of data lines and gate lines, but is not limited thereto.

At least three such adjacent subpixels (R-SP, G-SP, B-SP) can constitute one unit pixel for color display. For example, one unit pixel includes a red subpixel (R-SP), a green subpixel (G-SP), and a blue subpixel (B-SP) that are adjacent to each other, and may further include a white subpixel for brightness enhancement.

Each of these sub-pixels (R-SP, G-SP, B-SP) includes a micro-LED (120) that emits blue light, and a color conversion pattern (115a, 115b) is positioned above the micro-LED (120) for each sub-pixel (R-SP, G-SP, B-SP), so as to emit red, green, and blue light.

Looking at it in more detail, each subpixel (R-SP, G-SP, B-SP) includes an emitting area (EA) corresponding to the active layer (125) of the micro-LED (120), and a non-emitting area (NEA) is formed along the edge of the emitting area (EA).

And one side of the non-emitting region (NEA) includes a switching region (TrA) in which a driving thin film transistor (DTr) is formed.

A semiconductor layer (103) is positioned on the switching region (TrA). The semiconductor layer (103) is made of silicon, and its central portion is composed of an active region (103a) forming a channel, and source and drain regions (103b, 103c) doped with a high concentration of impurities on both sides of the active region (103a).

A gate insulating film (105) is positioned above the semiconductor layer (103).

A gate electrode (104) is provided on the upper portion of the gate insulating film (105) corresponding to the active region (103a) of the semiconductor layer (103), and the gate electrode (104) is connected to the gate line.

In addition, a first interlayer insulating film (106a) is positioned above the gate electrode (104) and the gate line, and at this time, the first interlayer insulating film (106a) and the gate insulating film (105) underneath it are provided with first and second semiconductor layer contact holes (107a, 107b) that expose source and drain regions (103b, 103c) located on both sides of the active region (103a), respectively.

Next, source and drain electrodes (109a, 109b) are provided on the upper portion of the first interlayer insulating film (106a) including the first and second semiconductor layer contact holes (107a, 107b) and are spaced apart from each other and contact the source and drain regions (103b, 103c) exposed through the first and second semiconductor layer contact holes (107a, 107b), respectively.

The source electrode (109a) is connected to the data line, and a common voltage wiring (108) is further formed parallel to the data line above the first interlayer insulating film (106a).

Optionally, a common voltage wire (108) may be provided for each of a plurality of unit pixels. In this case, at least three subpixels (SP1, SP2, SP3) constituting each unit pixel share one common voltage wire (108). Accordingly, the number of common voltage wires (108) for driving each subpixel (SP1, SP2, SP3) can be reduced, and the aperture ratio of each unit pixel can be increased or the size of each unit pixel can be reduced by the number of common voltage wires (108) that is reduced.

A second interlayer insulating film (106b) is positioned above the first interlayer insulating film (106a) exposed between the source and drain electrodes (109a, 109b), the common voltage wiring (108), and the two electrodes (109a, 109b).

At this time, the semiconductor layer (103) including the source and drain electrodes (109a, 109b) and the source and drain regions (103b, 103c) in contact with these electrodes (109a, 109b), the gate insulating film (105) and the gate electrode (104) located on the upper portion of the semiconductor layer (103) form a driving thin film transistor (DTr).

And, the switching thin film transistor (not shown) has the same structure as the driving thin film transistor (DTr) and is connected to the driving thin film transistor (DTr).

Here, the drawing shows a switching thin film transistor (not shown) and a driving thin film transistor (DTr) as an example of a top gate type in which a semiconductor layer (103) is made of a polysilicon semiconductor layer or an oxide semiconductor layer, but as a modified example, a bottom gate type made of pure and impurity amorphous silicon may be provided.

And, the second interlayer insulating film (106b) is provided with a drain contact hole (PH) that exposes the drain electrode (109b) of the driving thin film transistor (DTr), and a connection electrode (111) connected to the drain electrode (109b) of the driving thin film transistor (DTr) through the drain contact hole (PH) is positioned on the second interlayer insulating film (106b).

A reflective insulating film (113) is positioned on the upper portion of the substrate (101) including the connecting electrode (111), and a concave portion (113a) is provided in each reflective insulating film (113) corresponding to the light-emitting area (EA) of each subpixel (R-SP, G-SP, B-SP), and a micro-LED (120) is positioned within each concave portion (113a).

Accordingly, the reflective insulating film (113) is arranged to surround the outer surface of each micro-LED (120), and the reflective insulating film (113) reflects light emitted from the side of each micro-LED (120) among the light emitted from each micro-LED (120) toward the upper portion of the substrate (101), thereby improving the light efficiency of each micro-LED (120).

This reflective insulating film (113) can be formed of an oxide or nitride having excellent electrical insulation properties, and can be formed of an organic insulating layer having excellent durability and ductility, as well as excellent insulation properties, and enabling the production of a thick thin film.

Alternatively, the reflective insulating film (113) may be made of an insulating material including fine particles for light reflection, such as an insulating material of silicon oxide (SiOx) or silicon nitride (SiNx) having titanium oxide (TiO2) particles dispersed therein, but is not limited thereto.

And, this reflective insulating film (113) is formed to expose a part of the common voltage wiring (108).

Each micro-LED (120) positioned inside the concave portion (113a) of the reflective insulating film (113) for each of these sub-pixels (R-SP, G-SP, B-SP) includes a p-type electrode (121) connected to the connection electrode (111), a first semiconductor layer (123), an active layer (125), a second semiconductor layer (127) sequentially positioned above the p-type electrode (121), and a common electrode (129) electrically connected to the second semiconductor layer (127) and positioned apart from the p-type electrode (121).

The p-type electrode (121) can be formed as a reflective electrode using a metal with high reflectivity such as Ag, Al, Au, Cr, Ir, Mg, Nd, Ni, Pd, Pt, Rh, Ti, or W. Here, the p-type electrode (121) can also play a role in reflecting forward light emitted from the active layer (125) in the opposite direction rather than forward.

In addition, the p-type electrode (121) may be formed of an alloy of two or more metals having high reflectivity, or may be formed as a laminated structure of dissimilar metals, or may be formed as a laminated structure of an ITO, IZO, ZnO, or In2O3 film and a metal having high reflectivity.

Additionally, an adhesive layer to improve adhesion with the first semiconductor layer (123) or an ohmic connection layer to enable ohmic connection may be further laminated.

In addition, the p-type electrode (121) may be formed to have a smaller area than the first semiconductor layer (123) or may be formed to have the same area as the first semiconductor layer (123) so that the first semiconductor layer (123) is not exposed. The reason for forming the first semiconductor layer (123) so that it is not exposed is to increase the reflective surface and maximize the amount of light reflected by the reflective surface.

Here, the first semiconductor layer (123) is in contact with the p-type electrode (121) to provide holes to the active layer (125). This first semiconductor layer (123) may be made of a p-GaN-based semiconductor material, and the p-GaN-based semiconductor material may be GaN, AlGaN, InGaN, or AlInGaN. Here, Mg, Zn, or Be may be used as an impurity used for doping the first semiconductor layer (123).

And the active layer (125) positioned above the first semiconductor layer (123) may have a multi-quantum well (MQW) structure having a well layer and a barrier layer having a higher band gap than the well layer.

This active layer (125) can emit light when voltage is applied or current is supplied to the first and second semiconductor layers (123, 127).

The second semiconductor layer (127) is positioned above the active layer (125) and serves to provide electrons to the active layer (125). The second semiconductor layer (127) may be formed of an n-GaN-based semiconductor material. The n-GaN-based semiconductor material may be GaN, AlGaN, InGaN, or AlInGaN. Here, Si, Ge, Se, Te, or C may be used as an impurity for doping the second semiconductor layer (127).

Here, a portion of the first semiconductor layer (123) and the active layer (125) may be removed by mesa etching, thereby exposing a portion of the second semiconductor layer (127) on the lower surface.

In this way, the micro-LED (120) emits light according to the recombination of electrons and holes according to the current flowing between the p-type electrode (121) and the common electrode (129).

Here, the micro-LED display device (100) according to the first embodiment of the present invention is characterized in that the second semiconductor layer (127) is formed to protrude from the concave portion (113a) of the reflective insulating film (113), and the outer surface of the second semiconductor layer (127) protruding from the concave portion (113a) of the reflective insulating film (113) is surrounded by a silicon (Si) pattern (130).

In this way, by positioning the outer surface of the second semiconductor layer (127) of the micro-LED (120) protruding from the concave portion (113a) of the reflective insulating film (113) so that the silicon pattern (130) surrounds it, the silicon pattern (130) is positioned at the boundary of each sub-pixel (R-SP, G-SP, B-SP) and surrounds the edge of the light-emitting area (EA) of each sub-pixel (R-SP, G-SP, B-SP).

This silicon pattern (130) is part of a growth substrate of a micro-LED (120), and the micro-LED (120) is formed by growing on a growth substrate made of a silicon wafer. This silicon pattern (130) is substantially opaque to light emitted from the micro-LED (120) or significantly attenuates such light.

In addition, the silicon pattern (130) has high reflectivity and excellent thermal conductivity.

Accordingly, the micro-LED display device (100) according to the first embodiment of the present invention can prevent light leakage from occurring at the boundary of each sub-pixel (R-SP, G-SP, B-SP) or from being incident on an adjacent sub-pixel (R-SP, G-SP, B-SP) without having to position a separate black matrix between each sub-pixel (R-SP, G-SP, B-SP) of the color conversion pattern (115a, 115b) positioned above the micro-LED (120) by positioning the outer surface of the second semiconductor layer (127) protruding from the concave portion (113a) of the reflective insulating film (113) so that the silicon pattern (130) surrounds it.

Through this, the process for forming a black matrix can be omitted, which can lead to the effects of simplifying the process and reducing the process cost. In addition, by deleting the black matrix, some of the light emitted from the micro-LED (120) can be prevented from being absorbed by the black matrix, which also improves the light extraction efficiency of the micro-LED (120).

In addition, the high temperature heat generated in the process of driving the micro-LED (120) by the silicon pattern (130) can be quickly dissipated to the outside, thereby preventing a decrease in efficiency due to deterioration of the micro-LED (120).

In addition, the common electrode (129) can be formed using various materials, that is, by positioning the outer surface of the second semiconductor layer (127) protruding from the concave portion (113a) of the reflective insulating film (113) so that the silicon pattern (130) surrounds it, the common electrode (129) electrically connected to the second semiconductor layer (127) is formed by extending from the side surface of the second semiconductor layer (127) located in the concave portion (113a) of the reflective insulating film (113) between the reflective insulating film (113) and the silicon pattern (130).

Accordingly, since the common electrode (129) is formed only in the non-emitting area (NEA) excluding the emitting area (EA) of the micro-LED (120), the common electrode (129) can be formed of any material having conductivity in addition to a transparent material through which light can be transmitted.

For example, the common electrode (129) may be made of ITO, IZO, ZnO to transmit light emitted from the active layer (125), or may be formed of Ag, Al, Au, Cr, Ir, Mg, Nd, Ni, Pd, Pt, Rh, Ti, W, etc. having high reflectivity, or may be formed of an alloy of two or more of these metals or may be formed as a laminated structure of different metals.

At this time, although the common electrode (129) is depicted in a form that is separated for each sub-pixel (R-SP, G-SP, B-SP) in the drawing, the common electrode (129) is connected to all on the substrate (101) so that each micro-LED (120) can share the common electrode (129).

This common electrode (129) is electrically connected to the common voltage wiring (108) exposed by the reflective insulating film (113).

Each micro-LED (120) emits blue light from the active layer (125), and in the red and green sub-pixels (R-SP, G-SP), a color conversion pattern (115a, 115b) is positioned above each micro-LED (120) to convert short-wavelength light into long-wavelength light and emit it.

This is because blue light has a shorter wavelength than red light and green light, and the fluorescence efficiency of the color conversion pattern (115a, 115b) is slightly better for light of a shorter wavelength, and the color conversion pattern (115a, 115b) is slightly better in terms of lifespan, etc., when converting light of a relatively long wavelength into red light and green light, compared to when converting blue light of a relatively short wavelength.

However, the micro-LED (120) does not necessarily have to emit blue light, and may be composed of a micro-LED that emits red light or green light.

Here, a first color conversion pattern (115a) is positioned corresponding to the light-emitting area (EA) of the red subpixel (R-SP), and the first color conversion pattern (115a) can receive light and emit light of a first color. Specifically, the first color conversion pattern (115a) can be a layer that converts the received light into a wavelength of the first color.

Specifically, the first color may be red light having a wavelength of about 620 nm to 750 nm. However, the wavelength of the red light is not limited to the above example, and should be understood to include all wavelength ranges that can be recognized as red light in the art.

And, a second color conversion pattern (115b) is positioned corresponding to the light-emitting area (EA) of the green subpixel (G-SP). The second color conversion pattern (115b), like the first color conversion pattern (115a), is a layer that receives light and emits light of a second color. Specifically, it may be a layer that converts the received light into a wavelength of the second color.

The second color may be green having a wavelength of about 495 nm to 570 nm. However, it should be understood that the green light wavelength is not limited to the above examples and includes any wavelength range that can be recognized as green light in the art.

These first and second color conversion patterns (115a, 115b) include a color conversion material. The color conversion material may be, for example, a quantum dot, a fluorescent dye, or a combination thereof. The fluorescent dye includes, for example, an organic fluorescent material, an inorganic fluorescent material, and a combination thereof.

Quantum dots can be selected from, but are not limited to, group II-VI compounds, group III-V compounds, group IV-VI compounds, group IV elements, group IV compounds, and combinations thereof.

Group II-VI compounds are binary compounds selected from the group consisting of CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS and mixtures thereof; It may be selected from the group consisting of ternary compounds selected from the group consisting of CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS and mixtures thereof, and quaternary compounds selected from the group consisting of HgZnTeS, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe and mixtures thereof.

The group III-V compound may be selected from the group consisting of a binary compound selected from the group consisting of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, and mixtures thereof; a ternary compound selected from the group consisting of GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, and mixtures thereof; and a quaternary compound selected from the group consisting of GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, and mixtures thereof.

The group IV-VI compound may be selected from the group consisting of a binary compound selected from the group consisting of SnS, SnSe, SnTe, PbS, PbSe, PbTe and mixtures thereof; a ternary compound selected from the group consisting of SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe and mixtures thereof; and a quaternary compound selected from the group consisting of SnPbSSe, SnPbSeTe, SnPbSTe and mixtures thereof.

Group IV elements can be selected from the group consisting of Si, Ge, and mixtures thereof.

The Group IV compound may be a binary compound selected from the group consisting of SiC, SiGe, and mixtures thereof.

At this time, the binary, ternary or quaternary compound may exist within the particle at a uniform concentration, or may exist within the same particle with the concentration distribution partially divided into different states. In addition, one quantum dot may have a core/shell structure surrounding another quantum dot.

The interface between the core and the shell can have a concentration gradient in which the concentration of elements present in the shell decreases toward the center.

These quantum dots can have a full width of half maximum (FWHM) of an emission wavelength spectrum of about 45 nm or less, preferably about 40 nm or less, and more preferably about 30 nm or less, and color purity or color reproducibility can be improved in this range. In addition, since light emitted by these quantum dots is emitted in all directions, a wide viewing angle can be improved.

In addition, the shape of the quantum dot is not particularly limited to the commonly used shape, but more specifically, it can be used in the shape of spherical, pyramidal, multi-arm, or cubic nanoparticles, nanotubes, nanowires, nanofibers, nanoplatelet particles, etc.

The fluorescent dye can be, for example, a red fluorescent dye, a green fluorescent dye, a dye that emits light of a third color, or a combination thereof.

A red fluorescent dye is a material that absorbs light in a green wavelength range and emits light in a red wavelength range, and may be, for example, at least one of (Ca, Sr, Ba)S, (Ca, Sr, Ba)2Si5N8, CaAlSiN3, CaMoO4, Eu2Si5N8, K2SiF6, SrCaAlSiN3, CaS, and SrLiAlN3. In addition, the red fluorescent dye may be, for example, a material having a maximum emission peak at 617 nm to 637 nm and a full width at half maximum (FWHM) of 10 nm to 100 nm.

A green fluorescent dye is a material that absorbs light in the blue wavelength range and emits light in the green wavelength range, and may be, for example, at least one of yttrium aluminum garnet (YAG), (Ca, Sr, Ba)2SiO4, SrGa2S4, barium magnesium aluminate (BAM), alpha-SiAlON, beta-SiAlON, Ca3Sc2Si3O12, Tb3Al5O12, BaSiO4, CaAlSiON, Sr1-xBax)Si2O2N2, LuAG, (Ca, Sr, Ba)Si2O2N2, and GaS.

In addition, the green fluorescent dye may be, for example, a material having a maximum emission peak at 510 nm to 525 nm and a full width at half maximum (FWHM) of 60 nm to 70 nm. In a specific example, as the green fluorescent dye, a first green fluorescent dye having a maximum emission peak at 520 nm and a full width at half maximum (FWHM) of 62 nm and a second green fluorescent dye having a maximum emission peak at 511 nm and a full width at half maximum (FWHM) of 64 nm may be used. However, the green fluorescent dye is not limited to the examples described above.

Meanwhile, the fluorescent dyes listed so far can be made of inorganic fluorescent substances, and organic fluorescent substances can be made of BODIPY series fluorescent substances.

Additionally, Perovskite materials can also be applied.

In this way, since the first and second color conversion patterns (115a, 115b) are positioned in correspondence to the emission areas (EA) of the red and green sub-pixels (R-SP, G-SP) in each sub-pixel (R-SP, G-SP), the blue light emitted from each micro-LED (120) is wavelength-converted into red light by the first color conversion pattern (115a) positioned in the red sub-pixel (R-SP) in the red sub-pixel (R-SP), and the blue light is wavelength-converted into green light by the second color conversion pattern (115b) positioned in the green sub-pixel (G-SP) in the green sub-pixel (G-SP).

Accordingly, each of the red, green, and blue subpixels (R-SP, G-SP, B-SP) emits red light, green light, and blue light, so that the micro-LED display device (100) according to the first embodiment of the present invention implements high-brightness full color.

At this time, since the blue light of the image can be implemented as is through the blue light emitted from the micro-LED (120) in the blue sub-pixel (B-SP), nothing can be positioned in the blue sub-pixel (B-SP) or a transparent resin can be positioned so that the blue light emitted from the micro-LED (120) can be transmitted as is.

Alternatively, when the first and second color conversion patterns (115a, 115b) are made of quantum dots, the color purity of red and green light implemented from red and green subpixels (R-SP, G-SP) is improved, and the color purity can be maintained as it was at the beginning even after long-term light emission. Therefore, quantum dots can be included in the transparent resin even in the blue subpixel (B-SP).

That is, the blue light emitted from the micro-LED (120) reacts to the transparent resin corresponding to the blue sub-pixel (B-SP), so that blue quantum dots that emit light of a higher purity blue wavelength can be further distributed and positioned.

Here, the micro-LED display device (100) according to the first embodiment of the present invention can prevent the occurrence of light leakage at the boundary of each sub-pixel (R-SP, G-SP, B-SP) or light leakage caused by the blue light emitted from the micro-LED (120) provided in each sub-pixel (R-SP, G-SP, B-SP) being incident on an adjacent sub-pixel (R-SP, G-SP, B-SP) without providing a separate black matrix at the boundary of each sub-pixel (R-SP, G-SP, B-SP).

This is because the outer surface of the second semiconductor layer (127) of the micro-LED (120) protruding from the concave portion (113a) of the reflective insulating film (113) is wrapped by an opaque silicon pattern (130), so that the silicon pattern (130) is positioned to surround the edge of the light-emitting area (EA) of each sub-pixel (R-SP, G-SP, B-SP). As the silicon pattern (130) acts as a black matrix, light leakage caused by the silicon pattern (130) can be prevented.

In addition, the silicon pattern (130) has a higher reflectivity than the black matrix made of black resin, and through this, the micro-LED display device (100) according to the first embodiment of the present invention further improves the light efficiency of the micro-LED (120).

Below (Table 1) are the experimental results measuring the reflectivity of a typical black matrix and a silicon pattern (130).

Black Matrix Silicon pattern reflectivity(%) 0 ~ 5 30 ~ 60

(Inspecting Table 1), since a general black matrix is made of black resin, it absorbs almost all light (=color), resulting in a very small reflectance of 0 to 5%, but it can be confirmed that the opaque silicon pattern (130) has a reflectance of 30 to 60%, which is much higher than the black matrix. In this way, if the silicon pattern (130) with high reflectance is positioned in the non-emission area (NEA) surrounding the edge of the light-emitting area (EA) of each sub-pixel (R-SP, G-SP, B-SP), the light emitted from each sub-pixel (R-SP, G-SP, B-SP) and traveling to the non-emission area (NEA) can be reflected and extracted to the light-emitting area (EA).

Accordingly, the light efficiency of the micro-LED (120) is improved, and light leakage caused by reflection from adjacent sub-pixels (R-SP, G-SP, B-SP) can be further minimized.

In addition, by reflecting the light generated by reflection from adjacent subpixels (R-SP, G-SP, B-SP) and extracting it to the outside, the light efficiency of the micro-LED (120) is further improved.

In addition, the silicon pattern (130) also has a higher thermal conductivity than the black matrix made of black resin, and through this, the micro-LED display device (100) according to the first embodiment of the present invention further improves the light efficiency of the micro-LED (120).

Below (Table 2) are the experimental results measuring the thermal conductivity of a typical black matrix and a silicon pattern (130).

Black Matrix Silicon pattern Thermal Conductivity (W/K) 4 ~ 6 75

(As shown in Table 2), it can be seen that the general black matrix has a very low thermal conductivity of 4 to 6 W/K as it is made of black resin. In contrast, the silicon pattern (130) has a thermal conductivity of 75 W/K, which is very high compared to the black matrix. Through this, the micro-LED display device (100) according to the first embodiment of the present invention can quickly dissipate high-temperature heat generated in the process of driving the micro-LED (120) to the outside.

Through this, it is also possible to prevent the efficiency of the micro-LED (120) from being reduced due to deterioration.

As described above, the micro-LED display device (100) according to the first embodiment of the present invention can prevent light leakage from occurring at the boundary of each sub-pixel (R-SP, G-SP, B-SP) or from being incident on an adjacent sub-pixel (R-SP, G-SP, B-SP) without having to position a separate black matrix between each sub-pixel (R-SP, G-SP, B-SP) of the color conversion pattern (115a, 115b) positioned above the micro-LED (120) by positioning the outer surface of the second semiconductor layer (127) protruding from the concave portion (113a) of the reflective insulating film (113) so that the silicon pattern (130) surrounds it.

Through this, the process for forming a black matrix can be omitted, which can lead to the effects of simplifying the process and reducing the process cost. In addition, by deleting the black matrix, some of the light emitted from the micro-LED (120) can be prevented from being absorbed by the black matrix, which also improves the light extraction efficiency of the micro-LED (120).

In addition, the high temperature heat generated in the process of driving the micro-LED (120) by the silicon pattern (130) can be quickly dissipated to the outside, thereby preventing a decrease in efficiency due to deterioration of the micro-LED (120).

In addition, the common electrode (129) can be formed using various materials, which can reduce process costs and enhance process convenience, thereby improving process efficiency.

Hereinafter, a method for manufacturing a micro-LED display device according to the first embodiment of the present invention will be described with reference to FIGS. 2a to 2l.

FIGS. 2A to 2L are cross-sectional views showing manufacturing steps for three subpixels of a micro-LED display device according to a first embodiment of the present invention, and FIGS. 3A to 3B are cross-sectional views showing manufacturing steps for another three subpixels of a micro-LED display device according to the first embodiment of the present invention.

Before the explanation, the micro-LED display device (100 in FIG. 1) according to the first embodiment of the present invention is characterized by forming a micro-LED (120 in FIG. 1), so for the convenience of explanation, this will be mainly explained.

First, as shown in Fig. 2a, a home pattern (203) is formed on a growth substrate (201) corresponding to the light-emitting area (EA) of each subpixel (R-SP, G-SP, B-SP).

Here, the growth substrate (201) is made of a silicon wafer, and the growth substrate (201) made of a silicon wafer has the advantage of being inexpensive compared to a substrate made of sapphire.

The growth substrate (201) made of such a silicon wafer is substantially opaque to the light emitted from the micro-LED (120 in FIG. 1) or significantly attenuates such light.

In addition, the growth substrate (201) made of a silicon wafer has high reflectivity and excellent thermal conductivity.

Next, as shown in Fig. 2b, an epi growth process is performed on the entire surface of the growth substrate (201) including the home pattern (203).

Through an epi growth process, a second semiconductor material layer (227), an active material layer (225), and a first semiconductor material layer (223) can be sequentially formed, and the first and second semiconductor material layers (223, 227) and the active material layer (225) can each be formed of a nitride semiconductor.

That is, the second semiconductor material layer (227) may be formed of an n-GaN-based semiconductor material, and the n-GaN-based semiconductor material may be GaN, AlGaN, InGaN, or AlInGaN. Here, Si, Ge, Se, Te, or C may be used as an impurity for doping the second semiconductor material layer (227).

And the first semiconductor material layer (223) can be made of a p-GaN-based semiconductor material, and the p-GaN-based semiconductor material can be GaN, AlGaN, InGaN, or AlInGaN. Here, Mg, Zn, or Be can be used as an impurity used for doping the first semiconductor material layer (223).

The active material layer (225) may have a multi-quantum well structure such as InGaN/GaN, and emits blue light.

The first and second semiconductor material layers (223, 227) and the active material layer (225) represented by GaN can be epitaxially grown with excellent crystal quality on a growth substrate (201) made of a silicon wafer.

Here, the nitride semiconductor layer can be formed on the growth substrate (201) through a metal organic chemical vapor deposition (MOCVD) process, but is not limited thereto. For example, it can also be implemented through methods such as MBE (Molecular Beam Epitaxy), PECVD (Plasma Enhanced Chemical Vapor Deposition), and VPE (Vapor Phase Epitaxy). The MOCVD process can be performed at approximately 900 to 1300°C.

Next, as illustrated in FIG. 2c, the first and second semiconductor material layers (223, 227 of FIG. 2b) and the active material layer (225 of FIG. 2b) of the remaining area except the light-emitting area (EA) are removed, thereby forming the first and second semiconductor layers (123, 127) and the active layer (125) corresponding to the light-emitting area (EA) of each subpixel (R-SP, G-SP, B-SP), respectively.

This can be done by an etching process using a mask.

Additionally, a portion of the first semiconductor material layer (223 in FIG. 2b) and the active material layer (225 in FIG. 2b) may be further etched to expose a portion of the second semiconductor material layer (227 in FIG. 2b).

Next, as illustrated in FIG. 2d, a p-type electrode (121) is formed on the first semiconductor layer (123), and as illustrated in FIG. 2e, a common electrode (129) is formed to contact the side surface of the second semiconductor layer (127) corresponding to the non-emitting area (NEA) of the growth substrate (201), thereby completing a micro-LED (120) that emits blue light corresponding to the emitting area (EA) of each sub-pixel (R-SP, G-SP, B-SP).

Thereafter, as shown in Fig. 2f, a reflective insulating film (113) is formed on the front surface of the growth substrate (201).

The reflective insulating film (113) is positioned in the interspace between the micro-LEDs (120) corresponding to the light-emitting area (EA) of each sub-pixel (R-SP, G-SP, B-SP), so that a concave portion (113a) in which the micro-LEDs (120) are positioned is formed in the reflective insulating film (113).

Next, as illustrated in FIG. 2g, a reflective insulating film contact hole (113b) is formed to expose a common electrode (129) on one side of a non-emitting area (NEA) in a reflective insulating film (113), and then, as illustrated in FIG. 2h, a common electrode pillar (129a) in electrical contact with the common electrode (129) is formed inside the reflective insulating film contact hole (113b). Thereafter, as illustrated in FIG. 2i, a substrate (101) equipped with a driving thin film transistor (DTr) corresponding to a switching region (TrA) of a non-emitting region (NEA) is prepared, and then each micro-LED (120) formed corresponding to an emitting region (EA) of each sub-pixel (R-SP, G-SP, B-SP) is mounted such that the p-type electrode (121) of each micro-LED (120) is in contact with the connection electrode (111) connected to the drain electrode (109b) of the driving thin film transistor (DTr).

At this time, the common electrode pillar (129a) is brought into contact with the common voltage wiring (108) provided on the substrate (101).

Thereafter, as shown in Fig. 2j, the back surface of the growth substrate (201) on which the micro-LED (120) is grown is ground and then etched so that the second semiconductor layer (127) of each micro-LED (120) is exposed to the outside of the growth substrate (201).

Here, etching can use dry etching, and the dry etching process can be performed by using an etching gas of the CxFy series or SxFy series as the main reaction gas and a gas such as N2, Ar, or O2 as an auxiliary gas, at a low pressure of several mTorr to several hundred mTorr, independently applying a plasma source to the upper and RF in the range of several tens of KHz to GHz to the lower chuck to generate plasma and cause a chemical reaction.

Through this, as illustrated in FIG. 2k, the growth substrate (201) forms a silicon pattern (130) that surrounds the outer surface of the second semiconductor layer (127) protruding from the concave portion (113a) of the reflective insulating film (113).

These silicon patterns (130) are located at the boundary of each subpixel (R-SP, G-SP, B-SP) and surround the edge of the light-emitting area (EA) of each subpixel (R-SP, G-SP, B-SP).

Next, as illustrated in FIG. 2l, a first color conversion pattern (115a) is formed in the light-emitting area (EA) of the red subpixel (R-SP), and a second color conversion pattern (115b) is formed corresponding to the light-emitting area (EA) of the green subpixel (G-SP).

Through this, a micro-LED display device (100) according to the first embodiment of the present invention is completed.

Meanwhile, as illustrated in FIG. 3a, a common electrode (129) is formed to be in contact with the side surface of the second semiconductor layer (127) corresponding to the non-emitting area (NEA) of the growth substrate (201), and a micro-LED (120) that emits blue light corresponding to the emitting area (EA) of each sub-pixel (R-SP, G-SP, B-SP) is completed. Then, a common electrode pillar (129a) extending from the common electrode (129) may be further formed on one side of the non-emitting area (NEA).

And as illustrated in FIG. 3b, a substrate (101) equipped with a driving thin film transistor (DTr) corresponding to a switching region (TrA) of a non-emitting region (NEA) is prepared, and at this time, a reflective insulating film (113) is formed on the substrate (101) including a connection electrode (111) connected to a drain electrode (109b) of the driving thin film transistor (DTr), and the reflective insulating film (113) is provided with a concave portion (113a) corresponding to the emitting region (EA) of each subpixel (R-SP, G-SP, B-SP).

Thereafter, each micro-LED (120) formed corresponding to the light-emitting area (EA) of each sub-pixel (R-SP, G-SP, B-SP) of the growth substrate (201) may be settled into the concave portion (113a) of the reflective insulating film (113) so that the p-type electrode (121) of each micro-LED (120) comes into contact with the connection electrode (111) connected to the drain electrode (109b) of the driving thin film transistor (DTr).

- Example 2 -

FIG. 4 is a cross-sectional view showing three subpixels of a micro-LED display device according to a second embodiment of the present invention.

Meanwhile, in order to avoid redundant explanation, the same parts that play the same role as those described in the first embodiment mentioned above will be given the same reference numerals, and only the characteristic contents to be described in the second embodiment will be examined.

Before the explanation, each sub-pixel (R-SP, G-SP, B-SP) defined on the substrate (101) is equipped with a driving and switching thin film transistor (DTr, not shown), but for the convenience of explanation and the simplicity of the drawing, the driving thin film transistor (DTr) is shown only in one sub-pixel (R-SP, G-SP, B-SP).

As described above, the micro-LED display device (100) according to the second embodiment of the present invention has a plurality of sub-pixels (R-SP, G-SP, B-SP) defined on a substrate (101), includes an emitting area (EA) corresponding to an active layer (125a, 125b, 125c) of a micro-LED (120a, 120b, 120c), and forms a non-emitting area (NEA) along the edge of the emitting area (EA).

And, on one side of the non-emitting area (NEA), it includes a switching area (TrA) in which a driving thin film transistor (DTr) is formed.

On the switching region (TrA), a semiconductor layer (103) is positioned, which comprises an active region (103a) and source and drain regions (103b, 103c) doped with high concentrations of impurities on both sides of the active region (103a), a gate insulating film (105) and a gate electrode (104) positioned on the upper portion of the semiconductor layer (103), and a driving thin film transistor (DTr) which comprises source and drain electrodes (109a, 109b) in contact with the source and drain regions (103b, 103c).

At this time, a first interlayer insulating film (106a) is positioned above the gate electrode (104), and the source and drain electrodes (109a, 109b) come into contact with the source and drain regions (103b, 103c) of the semiconductor layer (103) through the first and second semiconductor layer contact holes (107a, 107b) provided in the first interlayer insulating film (106a) and the gate insulating film (105) underneath it.

And, a common voltage wiring (108) is further formed parallel to the data line on the upper portion of the first interlayer insulating film (106a), and a second interlayer insulating film (106b) is positioned on the upper portion of the first interlayer insulating film (106a) exposed between the source and drain electrodes (109a, 109b), the common voltage wiring (108), and the two electrodes (109a, 109b).

And, the second interlayer insulating film (106b) is provided with a drain contact hole (PH) that exposes the drain electrode (109b) of the driving thin film transistor (DTr), and a connection electrode (111) connected to the drain electrode (109b) of the driving thin film transistor (DTr) through the drain contact hole (PH) is positioned on the second interlayer insulating film (106b).

A reflective insulating film (113) is positioned on the upper portion of the substrate (101) including the connecting electrode (111), and a concave portion (113a) is provided in the reflective insulating film (113) corresponding to the light-emitting area (EA) of each subpixel (R-SP, G-SP, B-SP), and a micro-LED (120a, 120b, 120c) is positioned within each concave portion (113a).

Accordingly, the reflective insulating film (113) is arranged to surround the outer surface of each micro-LED (120a, 120b, 120c), thereby improving the light efficiency of each micro-LED (120a, 120b, 120c).

And, this reflective insulating film (113) is formed to expose a part of the common voltage wiring (108).

Here, each micro-LED (120a, 120b, 120c) positioned inside the concave portion (113a) of the reflective insulating film (113) for each sub-pixel (R-SP, G-SP, B-SP) includes a p-type electrode (121) connected to the connection electrode (111), a common electrode (129) positioned spaced apart from the p-type electrode (121), and first and second semiconductor layers (123, 127) and an active layer (125a, 125b, 125c) as a light-emitting portion positioned therebetween.

Here, the active layers (125a, 125b, 125c) emit light of different colors for each subpixel (R-SP, G-SP, B-SP). That is, the first micro-LED (120a) positioned in the light-emitting area (EA) of the red subpixel (R-SP) emits red light (red) from the first active layer (125a), and the second micro-LED (120b) positioned in the light-emitting area (EA) of the green subpixel (G-SP) emits green light (green) from the second active layer (125b).

And the third micro-LED (120c) located in the light-emitting area (EA) of the blue sub-pixel (B-SP) emits blue light (blue) from the third active layer (125c).

Accordingly, each of the red, green, and blue subpixels (R-SP, G-SP, B-SP) emits red light, green light, and blue light, so that the micro-LED display device (100) according to the second embodiment of the present invention implements high-brightness full color.

Here, the micro-LED display device (100) according to the second embodiment of the present invention is characterized in that the second semiconductor layer (127) is formed to protrude from the concave portion (113a) of the reflective insulating film (113), and the outer surface of the second semiconductor layer (127) protruding from the concave portion (113a) of the reflective insulating film (113) is surrounded by a silicon (Si) pattern (130).

In this way, by positioning the outer surface of the second semiconductor layer (127) of the micro-LED (120a, 120b, 120c) protruding from the concave portion (113a) of the reflective insulating film (113) so that the silicon pattern (130) surrounds it, the silicon pattern (130) is positioned at the boundary of each sub-pixel (R-SP, G-SP, B-SP) and surrounds the edge of the light-emitting area (EA) of each sub-pixel (R-SP, G-SP, B-SP).

This silicon pattern (130) is part of a growth substrate of a micro-LED (120a, 120b, 120c), and the micro-LED (120a, 120b, 120c) is formed by growing on a growth substrate made of a silicon wafer. This silicon pattern (130) is substantially opaque to light emitted from the micro-LED (120a, 120b, 120c) or significantly attenuates such light.

Additionally, the silicon pattern (130) has high reflectivity and excellent thermal conductivity.

Accordingly, the micro-LED display device (100) according to the second embodiment of the present invention can prevent light leakage from occurring at the boundary of each subpixel (R-SP, G-SP, B-SP) or light leakage from occurring by being incident on an adjacent subpixel (R-SP, G-SP, B-SP) without having to position a separate black matrix between each subpixel (R-SP, G-SP, B-SP) by positioning the outer surface of the second semiconductor layer (127) protruding from the concave portion (113a) of the reflective insulating film (113) so that the silicon pattern (130) surrounds it.

Through this, the process for forming a black matrix can be omitted, which can bring about the effects of simplifying the process and reducing the process cost, and also, by deleting the black matrix, some of the light emitted from the micro-LED (120a, 120b, 120c) can be prevented from being absorbed by the black matrix, which also improves the light extraction efficiency of the micro-LED (120a, 120b, 120c).

In addition, the high temperature heat generated in the process of driving the micro-LED (120a, 120b, 120c) by the silicon pattern (130) can be quickly dissipated to the outside, thereby preventing a decrease in efficiency due to deterioration of the micro-LED (120a, 120b, 120c).

In addition, the common electrode (129) can be formed using various materials, that is, by positioning the outer surface of the second semiconductor layer (127) protruding from the concave portion (113a) of the reflective insulating film (113) so that the silicon pattern (130) surrounds it, the common electrode (129) electrically connected to the second semiconductor layer (127) is formed by extending from the side surface of the second semiconductor layer (127) located in the concave portion (113a) of the reflective insulating film (113) between the reflective insulating film (113) and the silicon pattern (130).

Accordingly, since the common electrode (129) is formed only in the non-emitting area (NEA) excluding the emitting area (EA) of the micro-LED ((120a, 120b, 120c), the common electrode (129) can be formed of any material having conductivity in addition to a transparent material through which light can be transmitted.

At this time, although the common electrode (129) is depicted in a form that is separated for each sub-pixel (R-SP, G-SP, B-SP) in the drawing, the common electrode (129) is connected to all on the substrate (101) so that each micro-LED (120a, 120b, 120c) can share the common electrode (129).

FIGS. 5a and 5b are cross-sectional views showing three subpixels of a micro-LED display device according to another configuration of the second embodiment of the present invention.

Before the explanation, each sub-pixel (R-SP, G-SP, B-SP) defined on the substrate (101) is equipped with a driving and switching thin film transistor (DTr, not shown), but for the convenience of explanation and the simplicity of the drawing, the driving thin film transistor (DTr) is shown only in one sub-pixel (R-SP, G-SP, B-SP).

As described above, a micro-LED display device (100) according to another configuration of the second embodiment of the present invention has a plurality of sub-pixels (R-SP, G-SP, B-SP) defined on a substrate (101), and each of the plurality of sub-pixels (R-SP, G-SP, B-SP) may be defined by a crossing structure of data lines and gate lines, but is not limited thereto.

Each of these sub-pixels (R-SP, G-SP, B-SP) includes an emitting area (EA) corresponding to an active layer (125a, 125b, 125c) of a micro-LED (120a, 120b, 120c), and a non-emitting area (NEA) is formed along the edge of the emitting area (EA).

And one side of the non-emitting region (NEA) includes a switching region (TrA) in which a driving thin film transistor (DTr) is formed.

On the switching region (TrA), a semiconductor layer comprising an active region (103a) and source and drain regions (103b, 103c) doped with high concentrations of impurities on both sides of the active region (103a), a gate insulating film (105) and a gate electrode (104) positioned on the upper portion of the semiconductor layer (103), and a driving thin film transistor (DTr) comprising source and drain electrodes (109a, 109b) in contact with the source and drain regions (103b, 103c) is positioned.

At this time, a first interlayer insulating film (106a) is positioned above the gate electrode (104), and the source and drain electrodes (109a, 109b) come into contact with the source and drain regions (103b, 103c) of the semiconductor layer (103) through the first and second semiconductor layer contact holes (107a, 107b) provided in the first interlayer insulating film (106a) and the gate insulating film (105) underneath it.

At this time, a common voltage wiring (108) is further formed parallel to the data line on the upper side of the first interlayer insulating film (106a), and a second interlayer insulating film (106b) is positioned on the upper side of the first interlayer insulating film (106a) exposed between the source and drain electrodes (109a, 109b), the common voltage wiring (108), and the two electrodes (109a, 109b).

And, the second interlayer insulating film (106b) is provided with a drain contact hole (PH) that exposes the drain electrode (109b) of the driving thin film transistor (DTr), and a connection electrode (111) connected to the drain electrode (109b) of the driving thin film transistor (DTr) through the drain contact hole (PH) is positioned on the second interlayer insulating film (106b).

A reflective insulating film (113) is positioned on the upper portion of the substrate (101) including the connecting electrode (111), and a concave portion (113a) is provided in the reflective insulating film (113) corresponding to the light-emitting area (EA) of each subpixel (R-SP, G-SP, B-SP), and a micro-LED (120a, 120b, 120c) is positioned within each concave portion (113a).

Here, each micro-LED (120a, 120b, 120c) positioned inside the concave portion (113a) of the reflective insulating film (113) for each sub-pixel (R-SP, G-SP, B-SP) includes a p-type electrode (121) connected to the connection electrode (111), a common electrode (129) positioned spaced apart from the p-type electrode (121), and first and second semiconductor layers (123, 127) and an active layer (125a, 125b, 125c) as a light-emitting portion positioned therebetween.

The active layers (125a, 125b, 125c) emit light of different colors for each subpixel (R-SP, G-SP, B-SP). That is, the first micro-LED (120a) positioned in the light-emitting area (EA) of the red subpixel (R-SP) emits red light (red) from the first active layer (125a), and the second micro-LED (120b) positioned in the light-emitting area (EA) of the green subpixel (G-SP) emits green light (green) from the second active layer (125b).

And the third micro-LED (120c) located in the light-emitting area (EA) of the blue sub-pixel (B-SP) emits blue light (blue) from the third active layer (125c).

Accordingly, each of the red, green, and blue subpixels (R-SP, G-SP, B-SP) emits red light, green light, and blue light, so that the micro-LED display device (100) according to the second embodiment of the present invention implements high-brightness full color.

Here, a micro-LED display device (100) according to another configuration of the second embodiment of the present invention is characterized in that the second semiconductor layer (127) is formed to protrude from a concave portion (113a) of a reflective insulating film (113), and a silicon (Si) pattern (130) is positioned to surround an outer surface of the second semiconductor layer (127) protruding from the concave portion (113a) of the reflective insulating film (113).

In this way, by positioning the outer surface of the second semiconductor layer (127) of the micro-LED (120a, 120b, 120c) protruding from the concave portion (113a) of the reflective insulating film (113) so that the silicon pattern (130) surrounds it, the silicon pattern (130) is positioned at the boundary of each sub-pixel (R-SP, G-SP, B-SP) and surrounds the edge of the light-emitting area (EA) of each sub-pixel (R-SP, G-SP, B-SP).

This silicon pattern (130) is part of a growth substrate of a micro-LED (120a, 120b, 120c), and the micro-LED (120) is formed by growing on a growth substrate made of a silicon wafer. This silicon pattern (130) is substantially opaque to light emitted from the micro-LED (120a, 120b, 120c) or significantly attenuates such light.

Additionally, the silicon pattern (130) has high reflectivity and excellent thermal conductivity.

Therefore, a micro-LED display device (100) according to another configuration of the second embodiment of the present invention can prevent light leakage from occurring at the boundary of each subpixel (R-SP, G-SP, B-SP) or light leakage from occurring by being incident on an adjacent subpixel (R-SP, G-SP, B-SP) without having to position a separate black matrix between each subpixel (R-SP, G-SP, B-SP) by positioning the outer surface of the second semiconductor layer (127) protruding from the concave portion (113a) of the reflective insulating film (113) so that the silicon pattern (130) surrounds it.

Through this, the process for forming a black matrix can be omitted, which can bring about the effects of simplifying the process and reducing the process cost, and also, by deleting the black matrix, some of the light emitted from the micro-LED (120a, 120b, 120c) can be prevented from being absorbed by the black matrix, which also improves the light extraction efficiency of the micro-LED (120a, 120b, 120c).

In addition, the high temperature heat generated in the process of driving the micro-LED (120a, 120b, 120c) by the silicon pattern (130) can be quickly dissipated to the outside, thereby preventing a decrease in efficiency due to deterioration of the micro-LED (120a, 120b, 120c).

Here, as illustrated in FIG. 5a, a micro-LED display device (100) according to another configuration of the second embodiment of the present invention can form a common electrode (129) on top of a second semiconductor layer (127) protruding from a concave portion (113a) of a reflective insulating film (113) and a silicon pattern (130).

This common electrode (129) may be made of a transparent conductive oxide of the indium tin oxide (ITO), indium zinc oxide (IZO), indium tin zinc oxide (ITZO), zinc oxide (ZnO), and tin oxide (TO) series to transmit light emitted from the active layer (125a, 125b, 125c), but is not limited thereto.

This common electrode (129) is electrically connected to the common voltage wiring (108) exposed by the reflective insulating film (113) through the common electrode pillar (129a).

In this way, micro-LEDs (120a, 120b, 120c) emit light according to the recombination of electrons and holes according to the current flowing between the p-type electrode (121) and the common electrode (129).

Alternatively, as illustrated in FIG. 5b, the common electrode (129) may be omitted, whereby at least a portion of the silicon pattern (130) may be made conductive through element doping, so that the silicon pattern (130) itself can serve as the common electrode (129).

Silicon has an electrical resistivity (ρ) of 2.3 × 105 (Ω m), but by adding B or P as impurities, it can be used as a p-type semiconductor material or an n-type semiconductor material, and as a semiconductor with a wide operating temperature range, it can control current.

The additive elements for making silicon into a p-type semiconductor material are each group of additive elements A (Be, Mg, Ca, Sr, Ba, Zn, Cd, Hg, B, Al, Ga, In, Tl) and transition metal elements M1 (Y, Mo, Zr), and the additive elements for making silicon into an n-type semiconductor material are each group of additive elements B (N, P, As, Sb, Bi, O, S, Se, Te), transition metal elements M2 (Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Nb, Ru, Rh, Pd, Ag, Hf, Ta, W, Re, Os, Ir, Pt, Au, but Fe is less than 10 at%), and rare earth elements RE (RE; La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Lu).

In this way, by making the silicon pattern (130) surrounding the outer surface of the second semiconductor layer (127) protruding from the concave portion (113a) of the reflective insulating film (113) conductive through element doping, the silicon pattern (130) itself can take the place of the common electrode (129), so that a separate common electrode (129) can be omitted.

At this time, in the non-display area (NEA), a common electrode pillar (129a) extending from the silicon pattern (130) can be further formed, and the common electrode pillar (129a) is brought into contact with the common voltage wiring (108) provided on the substrate (101), so that the micro-LED (120a, 120b, 120c) emits light according to the recombination of electrons and holes according to the current flowing between the p-type electrode (121) and the silicon pattern (130).

As described above, the micro-LED display device (100) according to the second embodiment of the present invention can prevent light leakage from occurring at the boundary of each sub-pixel (R-SP, G-SP, B-SP) or from being incident on an adjacent sub-pixel (R-SP, G-SP, B-SP) without having to position a separate black matrix between each sub-pixel (R-SP, G-SP, B-SP) of the color conversion patterns (115a, 115b) positioned above the micro-LEDs (120a, 120b, 120c) by positioning the outer surface of the second semiconductor layer (127) protruding from the concave portion (113a) of the reflective insulating film (113) so that the silicon pattern (130) surrounds it.

Through this, the process for forming a black matrix can be omitted, which can bring about the effects of simplifying the process and reducing the process cost, and also, by deleting the black matrix, some of the light emitted from the micro-LED (120a, 120b, 120c) can be prevented from being absorbed by the black matrix, which also improves the light extraction efficiency of the micro-LED (120a, 120b, 120c).

In addition, the high temperature heat generated in the process of driving the micro-LED (120a, 120b, 120c) by the silicon pattern (130) can be quickly dissipated to the outside, thereby preventing a decrease in efficiency due to deterioration of the micro-LED (120a, 120b, 120c).

In addition, the common electrode (129) can be formed using various materials, which can reduce process costs and enhance process convenience, thereby improving process efficiency.

The present invention is not limited to the above embodiments, and may be implemented by making various changes without departing from the spirit of the present invention.

100: Micro-LED display device, 101: Substrate
103: Semiconductor layer (103a: active region, 103b, 103c: source and drain regions)
105: Gate insulating film, 106a, 106b: First and second interlayer insulating films
107a, 107b: 1st, 2nd semiconductor contact hole, 108: Common voltage wiring
109a, 109b: source and drain electrodes, 111: connection electrode
113: Reflective insulating film (113a: concave portion), 115a, 115b: First and second color conversion patterns
120: Micro-LED (121: p-type electrode, 123: first semiconductor layer, 125: active layer, 127: second semiconductor layer, 129: common electrode)
130 : Silicon pattern

Claims (14)

A substrate having a first subpixel expressing a first color and a second subpixel expressing a second color having a wavelength band larger than that of the first color and positioned adjacent to the first subpixel, the substrate being defined;
A light emitting diode, each positioned in the light emitting area of the first and second subpixels, including first and second semiconductor layers and an active layer positioned between the first and second semiconductor layers;
A silicon pattern arranged to surround a portion of the outer surface of the second semiconductor layer, corresponding to a non-luminous region surrounding the edge of the luminous region.
Including,
An LED display device further comprising a common voltage wiring positioned on the substrate, wherein the silicon pattern, the common voltage wiring, and the second semiconductor layer are electrically connected to each other.
In paragraph 1,
The light-emitting diode includes a p-type electrode electrically connected to the first semiconductor layer, and a common electrode electrically connected to the second semiconductor layer and located in the non-emitting region.
An LED display device in which the p-type electrode is electrically connected to a driving thin film transistor positioned on the substrate, and the common electrode is electrically connected to the common voltage wiring positioned on the substrate.
A substrate having a first subpixel expressing a first color and a second subpixel expressing a second color having a wavelength band larger than that of the first color and positioned adjacent to the first subpixel, the substrate being defined;
A light emitting diode, each positioned in the light emitting area of the first and second subpixels, including first and second semiconductor layers and an active layer positioned between the first and second semiconductor layers;
A silicon pattern arranged to surround a portion of the outer surface of the second semiconductor layer, corresponding to a non-luminous region surrounding the edge of the luminous region.
Including,
The light-emitting diode includes a p-type electrode electrically connected to the first semiconductor layer, and a common electrode electrically connected to the second semiconductor layer and located in the non-emitting region.
The above p-type electrode is electrically connected to a driving thin film transistor positioned on the substrate, and the above common electrode is electrically connected to a common voltage wiring positioned on the substrate.
An LED display device in which the common electrode is positioned so as to extend from the side of the second semiconductor layer to the bottom of the silicon pattern.
In the second paragraph,
An LED display device in which the above common electrode is positioned above the second semiconductor layer and the silicon pattern.
In paragraph 1,
An LED display device in which the upper surface of the above silicon pattern and the upper surface of the second semiconductor layer are positioned on the same plane.
In paragraph 1,
A third subpixel is included adjacent to the second subpixel,
An LED display device in which each of the light-emitting diodes of the first to third sub-pixels emits light of a different color.
In paragraph 1,
The light emitting diodes of the first and second subpixels emit the first color,
An LED display device including a first color conversion pattern positioned corresponding to the light-emitting area of the second subpixel and wavelength-converting the first color into the second color.
In paragraph 7,
A third color having a wavelength band larger than that of the second color is expressed, and a third subpixel is included that is arranged adjacent to the second subpixel,
An LED display device including a second color conversion pattern positioned corresponding to the third subpixel and wavelength-converting the first color into the third color.
In Article 8,
An LED display device wherein the first color is blue light, the second color is green light, and the third color is red light.
In Article 8,
The above first color conversion pattern includes a quantum dot that converts the first color into the second color,
An LED display device in which the second color conversion pattern includes quantum dots that convert the first color into the third color.
In paragraph 1,
An LED display device in which a reflective insulating film including concave portions each corresponding to the light-emitting area is positioned on the front surface of the substrate, and the light-emitting diodes are each positioned in the concave portions.
A step of forming a home pattern corresponding to the light-emitting area of each subpixel on a growth substrate;
A step of sequentially epitaxially growing a second semiconductor material layer, an active material layer, and a first semiconductor material layer on the growth substrate;
A step of etching the second semiconductor material layer, the active material layer, and the first semiconductor material layer, excluding the light-emitting area on the growth substrate, to form first and second semiconductor layers and an active layer, respectively, corresponding to the light-emitting area of each subpixel;
A step of forming a p-type electrode on top of the first semiconductor layer;
A step of forming a common electrode in electrical contact with the second semiconductor layer;
A step of closely contacting a driving substrate equipped with a driving thin film transistor for each of the above sub-pixels to the growth substrate so that the p-type electrode is electrically connected to a connection electrode that is electrically connected to the drain electrode of the driving thin film transistor;
A step of forming a silicon pattern by etching the back surface of the growth substrate so that at least a portion of the surface of the second semiconductor layer is exposed to the outside and surrounds the outer surface of the second semiconductor layer.
A method for manufacturing an LED display device including:
In Article 12,
The active layer located in each of the above subpixels emits blue light,
A step of forming a first color conversion pattern that converts the blue light into red light on the upper part of the second semiconductor layer, corresponding to a red subpixel among each of the above subpixels;
A step of forming a second color conversion pattern that converts the blue light into green light on top of the second semiconductor layer, corresponding to the green subpixel among each of the above subpixels.
A method for manufacturing an LED display device including:
In Article 12,
A method for manufacturing an LED display device, further comprising a step of doping an element into the above silicon pattern.