KR102450451B1 - Led array display panel and method for making the same - Google Patents

Abstract

An LED display panel is disclosed. The LED display panel includes a light-transmitting base portion including a first surface and a second surface opposite thereto; a submount substrate facing the second surface of the base part; a plurality of epitaxial cells interposed between the base part and the submount substrate and arranged in a matrix arrangement on a second surface of the base part; and a wavelength conversion unit coupled to the first surface of the base unit and converting wavelengths of the light emitted from the plurality of epitaxial cells, wherein the wavelength conversion unit includes a quantum dot film and an upper surface of the quantum dot film. and a light-transmitting upper passivation layer formed on the upper passivation layer, wherein a plurality of anti-spreading patterns respectively corresponding to the plurality of epitaxial cells EC are formed on the upper passivation layer.

Description

LED display panel and manufacturing method thereof

The present invention relates to an LED display panel including a micro LED in which a plurality of epitaxial cells are formed and a wavelength conversion unit for wavelength-converting light emitted from the plurality of epitaxial cells, and more particularly, to a wavelength emitted from the epitaxial cell. The present invention relates to an LED display panel in which contrast is remarkably improved by suppressing light emitted along a light path passing through a conversion unit from affecting an adjacent light path through which light emitted from an adjacent corresponding epitaxial proceeds.

By the applicant of the present invention, research on the LED display panel is being made. An LED display panel under study is a micro LED including a sapphire substrate and/or a base including an epitaxial base, and a plurality of gallium nitride-based epitaxial cells arranged in a matrix arrangement on the base on a submount substrate. It is manufactured by mounting by a flip chip bonding method.

The micro LED is an undoped GaN semiconductor layer, an n-type semiconductor layer, an active layer, and an epitaxial layer including a p-type semiconductor layer, which are sequentially grown on a sapphire substrate, and then at least the thickness of the p-type semiconductor layer and the active layer A lattice-type trench is formed to a depth including the thickness, and is manufactured to include an epitaxial base including an n-type semiconductor layer, and a plurality of epitaxial cells including at least an active layer and a p-type semiconductor layer. However, the gallium nitride-based micro LED can emit blue light, green light, or ultraviolet light when a current is applied to each epitaxial cell, but cannot emit red light, so there is a limitation in being used for display purposes. In contrast, it may be considered to use a quantum dot for wavelength-converting blue light emitted from an epitaxial cell into red light. However, when a quantum dot is applied, there is a sapphire substrate having a greater thickness in addition to the epitaxial base between the quantum dot and the epitaxial cell, and the light emitted from the epitaxial cell is spread through the sapphire substrate. , which causes poor contrast.

On the other hand, the inventor of the present invention has made a study to improve the contrast by removing the sapphire substrate from the epitaxial base or by reducing the thickness of the epitaxial base formed on the sapphire substrate.

However, there was still a problem of light spreading in the wavelength conversion unit from which the wavelength-converted light finally exits, and a decrease in contrast resulting therefrom.

Therefore, the problem to be solved by the present invention is to provide a wavelength conversion panel with means for reducing the spread of light coming out of the corresponding epitaxial cell and going through the wavelength conversion panel, so that the optical path from the epitaxial cell through the wavelength conversion panel It relates to an LED display panel in which contrast is remarkably improved by suppressing the influence of a specific light traveling along the adjacent light path from an adjacent corresponding epitaxial.

An LED display panel according to an aspect of the present invention includes a light-transmitting base portion including a first surface and a second surface opposite thereto; a submount substrate facing the second surface of the base part; a plurality of epitaxial cells interposed between the base part and the submount substrate and arranged in a matrix arrangement on a second surface of the base part; and a wavelength conversion unit coupled to the first surface of the base unit to correspond to the plurality of epitaxial cells and converting wavelengths of light emitted from the plurality of epitaxial cells, wherein the wavelength conversion unit is a quantum dot film (Quantum dot film). ) and a light-transmitting upper passivation layer formed on the upper surface of the quantum dot film, wherein the upper passivation layer has a plurality of anti-spreading patterns each corresponding to a plurality of epitaxial cells EC. is formed, and the anti-spreading pattern is such that light emitted from the corresponding epitaxial cell and passing through the wavelength conversion unit is diffused to the light propagation path of another epitaxial cell adjacent to the corresponding epitaxial cell. restrain

In an embodiment, the plurality of anti-spreading patterns are formed on a light exit surface of the upper passivation layer.

According to an embodiment, each of the plurality of anti-spreading patterns includes a plurality of v-shaped grooves.

According to an embodiment, the plurality of anti-spreading patterns include a Fresnel lens pattern or a prism lens pattern.

According to an embodiment, the plurality of anti-spreading patterns include a concave pattern collecting light passing therethrough.

According to an embodiment, the wavelength converter further includes a light-transmitting lower protective layer formed on a bottom surface of the quantum dot film.

According to an embodiment, the quantum dot film has a thickness of 100 μm or less.

According to an embodiment, the anti-spreading pattern is formed by etching or laser processing.

In an exemplary embodiment, the base part includes a base epitaxial layer from which the sapphire substrate is removed, and the wavelength converter is coupled to a surface of the base epitaxial layer from which the sapphire substrate is removed.

In an exemplary embodiment, the base part includes a sapphire substrate having a reduced thickness and a base epitaxial layer formed on the sapphire substrate having a reduced thickness, and the wavelength converter is coupled to a reduced thickness surface of the sapphire substrate.

An LED display panel according to an aspect of the present invention includes a light-transmitting base portion including a first surface and a second surface opposite thereto; a submount substrate facing the second surface of the base part; a plurality of epitaxial cells interposed between the base part and the submount substrate and arranged in a matrix arrangement on a second surface of the base part; and a wavelength conversion unit coupled to the first surface of the base unit to correspond to the plurality of epitaxial cells and converting wavelengths of light emitted from the plurality of epitaxial cells, wherein the wavelength conversion unit is a quantum dot film (Quantum dot film). ) and a hole layer positioned above the quantum dot film, wherein the hole layer includes a plurality of holes formed directly on the plurality of epitaxial cells to correspond to the plurality of epitaxial cells, and the hole layer includes a corresponding epitaxial cell. Light emitted from the cell and passing through the wavelength conversion unit is emitted only through the hole.

In this case, the wavelength conversion unit further includes an upper protective layer having light transmittance between the quantum dot film and the hole layer, wherein the hole layer has a plurality of holes in the light opaque material layer coated on the upper surface of the upper protective layer. formed and made

1 is a cross-sectional view for explaining an LED display panel including a wavelength converter including a semi-diffusion pattern according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view illustrating an LED display panel including a semi-diffusion pattern of FIG. 1 and a semi-diffusion pattern of another example.
3 is a diagram illustrating a micro LED including an epitaxial base and a plurality of epitaxial cells on a sapphire substrate.
FIG. 4 is a diagram schematically illustrating a submount substrate on which the micro LED shown in FIG. 2 is mounted.
FIG. 5 is a view for explaining that the micro LED shown in FIG. 2 is mounted on the submount substrate shown in FIG. 3 .
6 is a diagram illustrating that an energy absorbing layer or a bonding force enhancing layer is filled between the micro LED and the submount substrate.
7 is a diagram illustrating sapphire removal by laser lift-off.
FIG. 8 is a view illustrating coupling a wavelength converter including a quantum dot film to the surface from which the sapphire substrate of FIG. 6 is removed.
9 is a view for explaining other embodiments of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. Since the accompanying drawings and embodiments are simplified and exemplified so that those of ordinary skill in the art to which the present invention pertain can easily understand, the drawings and embodiments should not be construed as limiting the scope of the present invention. no it will be

Referring to FIG. 1 , an LED display panel according to an embodiment of the present invention includes a micro LED ( 100), a submount substrate 200 on which the micro LED 100 is mounted by a flip-chip bonding method, and a wavelength converter 300 coupled to the base portion B.

In the micro LED 100, the base portion B includes a first surface and a second surface opposite thereto. In addition, the plurality of epitaxial cells EC are arranged in a matrix arrangement while being formed on the second surface of the base part B. The base portion (B) is formed on the sapphire substrate, and the n-type semiconductor layer 114 formed on the undoped semiconductor layer 112 and the undoped semiconductor layer 112 remaining after the sapphire substrate is removed. a base epitaxial layer comprising In addition, each of the plurality of epitaxial cells EC includes an active layer 116 and a p-type semiconductor layer 118 . In this case, a portion of the n-type semiconductor layer 114 may also be included in the epitaxial cell EC. In this embodiment, since the sapphire substrate is completely removed, the base portion B consists of only the epitaxial layer, but when only a part of the thickness of the sapphire substrate is removed, the base portion B is formed with the base epitaxial layer. , may further include a sapphire substrate having a reduced thickness.

An individual electrode pad 150 is formed on the p-type semiconductor layer 118 of each of the epitaxial cells EC, and the second surface of the base portion B is an exposed surface of the n-type semiconductor layer 114 . As such, the common electrode pad 160 is formed. The common electrode pad 160 is formed in an outer region surrounding the central region of the second surface region of the base portion B, not in the central region in which the plurality of epitaxial cells EC are formed.

The submount substrate 200 includes a plurality of inner electrodes 250 corresponding to a plurality of individual electrode pads 150 and an outer electrode 240 corresponding to the common electrode pad 160 with the micro LED 100 . placed on the opposite side. The submount substrate 200 may include a plurality of CMOS cells (not shown) corresponding to the plurality of epitaxial cells EC provided in the micro LED 100 . The above-described inner electrode 250 or outer electrode 240 may be connected to each of the plurality of CMOS cells. In a state in which the micro LED 100 is mounted on the submount substrate 200, the submount substrate 200 faces the second surface of the base portion B, and the plurality of epitaxial cells ( EC) is interposed between the second surface of the base part B and the submount substrate 200 .

At this time, the plurality of individual electrode pads 150 formed on the p-type semiconductor layer 118 of the plurality of epitaxial cells EC are connected to the plurality of inner electrodes 250 by the plurality of inner solder bumps 270 . The common electrode pad 160 that is bonded and formed on the n-type semiconductor layer 114 of the base portion B is connected to the outer electrode 240 by an outer solder bump 260 .

In addition, as mentioned above, the base portion B includes a second surface on which the epitaxial cells EC are formed and a first surface opposite thereto, and the first surface is an epitaxial surface from which the sapphire substrate is completely removed. The taxial layer may be the surface or the sapphire substrate surface remaining after a portion of the sapphire substrate has been removed.

In this embodiment, the sapphire substrate is removed by a laser lift-off process, the laser passing through the sapphire heats the undoped semiconductor layer 112, that is, the u-GaN layer 112, and by this heating, By decomposing the u-GaN layer into Ga and N, the sapphire substrate can be removed.

The LED display panel according to the present embodiment includes a wavelength conversion unit 300 coupled to the first surface of the base portion (B). Preferably, the wavelength converter 300 includes a quantum dot film 302 having a predetermined thickness, a lower protective layer 301 formed on a lower surface of the quantum dot film 302 and the quantum dot film. and an upper protective layer 303 formed on the upper surface of the 302 .

The quantum dot film 302 is manufactured in the form of a film using a material in which quantum dot particles capable of converting blue light into red light are mixed with a light-transmitting resin. The quantum dot film 302 has a thickness smaller than that of the existing quantum dot film, that is, 100 μm or less, and also has a higher quantum dot concentration than the quantum dot concentration in the existing quantum dot film. It is configured to reduce the half width and improve light extraction efficiency.

The lower protective layer 301 and the upper protective layer 303 preferably have a hardness value of 5 to 9H, and are preferably formed by coating a PET material on the upper and lower surfaces of the quantum dot film 302 . The lower protective layer 301 and the upper protective layer 303 serve to protect quantum dot particles in the quantum dot film 302, which are vulnerable to heat and moisture, from the heat and moisture.

In addition, the lower protective layer 301 is a portion interposed between the quantum dot film 302 and the base portion B, and the smaller the thickness thereof, the less the amount of light that spreads out of a target direction is reduced. Also, it is possible to reduce the loss of light, thereby increasing the light efficiency.

In addition, as the thickness of the upper protective layer 303 is smaller, the amount of light that spreads out of a target path can be reduced, and light loss can be reduced, thereby increasing light efficiency. However, there is a limit to reducing the thickness of the lower passivation layer 301 and the upper passivation layer 303, and even if the thickness is reduced, light is spread due to a difference in refractive index between the upper passivation layer 303 and the outside air. There is a limit to restraining going out.

In particular, the upper hobo layer 303 includes a light incident surface in contact with the quantum dot film 302 and a light outgoing surface in contact with air on the opposite side. Light from the taxial cell EC may pass through a target optical path through which the light must travel and affect the optical path from the adjacent epitaxial cell EC.

In contrast, the wavelength conversion unit 300 according to the embodiment of the present invention is formed to correspond to each of the plurality of epitaxial cells EC, and is emitted from the corresponding epitaxial cell EC to the wavelength conversion unit ( A plurality of anti-spreading patterns 303a are applied to the light exit surface of the upper protective layer 303 to prevent the light passing through 300 from being diffused into the propagation path of the light emitted from the adjacent epitaxial cell EC. include The semi-diffusion pattern 303a may be a Fresnel pattern capable of converting passing light into parallel light and outputting the light as in the present embodiment. Alternatively, the semi-diffusion pattern 303a is a prismatic semi-diffusion pattern composed of a plurality of v-shaped grooves (not shown) or a concave lens-type semi-diffusion pattern 303b that collects and emits spread light; see FIG. 2 . ) can be

Referring back to FIG. 1 , the LED display panel according to the present embodiment includes the inner and outer electrodes 250 and 240 on the submount substrate 200 side, respectively, on the micro LED 100 side electrode pads 150 and 160 . ) includes a plurality of bonding connections 260 and 270 connected to the , that is, an outer solder bump 260 and an inner solder bump 270 .

In the present embodiment, each of the plurality of bonding connectors 270 and 260 may include a Cu pillar and solder formed on the Cu pillar. Instead of the bumps 270 and 260 including Cu pillars, solder bumps, solder balls, or ACFs including other metal materials may be used.

The solder constituting at least a portion of the bonding connection portions 270 and 260 is formed of a SnAg solder material and maintains an original hemispherical shape, but is compressed and deformed in a semi-molten state to be bonded to the electrode pads 160 and 150 .

In addition, the micro LED module according to the present embodiment includes an energy absorbing layer 700 between the micro LED 100 and the submount substrate 200 . The energy absorbing layer 700 is, for example, formed of an insulating adhesive material having an adhesive force such as epoxy or silicone, and after the micro LED 100 is mounted on the submount substrate 200, the micro LED by a laser lift-off process. When the sapphire substrate and the undoped semiconductor layer are removed from the n-type semiconductor layer 114 of (100), there is no epitaxial cell (EC) and the laser energy passing through the thin base part (B) is absorbed. The energy prevents the circuit on the submount substrate from being damaged. In addition, the energy absorbing layer 700 serves as a bonding force strengthening part that strengthens the bonding force between the micro LED 100 and the submount substrate 200, and during the laser lift-off process, the micro LED 100 and the submount substrate ( 200) makes it smaller than the bonding force between the submount 200 and the micro LED 100 reinforced by the bonding force reinforcing layer 700, and through this, the sapphire substrate can be stably separated.

The energy absorbing layer 700 is completely filled between the micro LED 100 and the submount substrate 200, and bonding connection parts 260 and 270 for connecting the electrode pads 150 and 160 and the electrodes 240 and 250 to each other. ) to cover the entire side of each of them.

Hereinafter, the micro LED manufacturing process and the micro LED mounting process on the submount substrate will be described in order.

First, a micro LED 100 as shown in FIG. 3 is manufactured. The micro LED 100 has a sapphire substrate 131, a first surface in contact with the sapphire substrate 131, and a second surface opposite thereto, a gallium nitride-based base epitaxial layer EB, and the base epitaxial layer. It includes a plurality of epitaxial cells EC arranged in a matrix arrangement on the second side of (EB).

The base epitaxial layer EB and the epitaxial cell EC include an undoped semiconductor layer 112 , an n-type semiconductor layer 114 , an active layer 116 , and a p-type grown on the sapphire substrate 131 . It is part of the epitaxial layer of the gallium nitride-based epitaxial layer including the semiconductor layer 118 . After the epitaxial layer is grown on the sapphire substrate 131 , a lattice-type trench is formed to a depth including at least the thickness of the p-type semiconductor layer 118 and the thickness of the active layer 116 of the epitaxial layer, so that the n-type A base epitaxial layer EB including the semiconductor layer 114 over the entire planar region, and a plurality of epitaxial cells EC including at least an active layer 116 and a p-type semiconductor layer 118 are formed.

In addition, individual electrode pads 150 are formed on the p-type semiconductor layer 118 of each of the epitaxial cells EC, and the second of the base epitaxial layer EB on which the plurality of epitaxial cells EC are formed. A common electrode pad 160 is formed in the second outer region of the base epitaxial layer EB surrounding the inner region.

The size of the epitaxial cell 130 of the micro LED 100 prepared as above is preferably 5 μm or less, and therefore, the size of the p-type individual electrode pad 150 formed in each epitaxial cell 130 is less than 5 μm. desirable.

Referring to FIG. 4 , before the pillar bump forming step, a Si-based submount substrate 200 having a size of approximately 15,000 μm×10,000 μm and in which CMOS cells corresponding to epitaxial cells are formed is prepared. The submount substrate 200 includes a Si-based substrate base material 201, a plurality of CMOS cells (not shown) provided in the substrate base material 201 corresponding to the plurality of epitaxial cells described above, and a micro LED. A plurality of individual electrodes 250 corresponding to the p-type electrode pads, that is, the inner electrodes 250, and the common electrode 240 corresponding to the n-type electrode pad of the micro LED, that is, the outer electrode 240 are formed. may include

Next, as shown in FIG. 5, a submount substrate 200 based on a Si substrate base material having a thermal expansion coefficient of 2.6 µm -1K is 7.6 µm − which reaches about 2.5 times the thermal expansion coefficient of the Si substrate base material. Flip-chip bonding between the micro LEDs 100 based on the sapphire substrate 131 having a coefficient of thermal expansion of 1K is performed.

As mentioned above, the submount substrate 200 includes a plurality of electrodes provided to correspond to the electrode pads 150 and 16 of the micro LED 100, and each of the plurality of electrodes includes, for example, a Cu pillar and Solder bumps 260 and 270 made of SnAg solder are formed in advance.

By flip-chip bonding the micro LED 100 to the submount substrate 200 using the solder bumps 260 and 270, the electrode pads 150 and 160 of the micro LED 100 are connected to the electrodes ( 240, 250) are connected. Solder between the micro LED 100 and the submount substrate 200 , more specifically, between the electrode pad 150 and the submount substrate 200 formed in each epitaxial cell 130 of the micro LED 100 . The interposed solder bumps 260 and 270 are heated, so that the micro LED 100 and the submount substrate 200 are flip-chip bonded. Anisotropic Conductive Film (ACF) may be advantageously used instead of solder bumps. In addition, in performing flip-chip bonding, a laser bonding method may be advantageously used to heat a solder material included in solder bumps or the like. Laser bonding uses a laser that sequentially passes through the sapphire substrate 131, the gallium nitride-based base epitaxial layer EB, and the epitaxial cell EC. The laser is irradiated to the electrode pad or the solder bump to heat the solder bump.

Next, as shown in FIG. 6 , an energy absorption layer 700 is formed between the micro LED 100 and the submount substrate 200 .

The energy absorbing layer 700 is, for example, formed of an insulating adhesive material having an adhesive force such as epoxy or silicone, and after the micro LED 100 is mounted on the submount substrate 200, the micro LED by a laser lift-off process. When the sapphire substrate and the buffer layer are removed from the n-type semiconductor layer 132 of (100), the laser energy that has passed through the thin base epitaxial layer EB is absorbed because there is no epitaxial cell EC, and the energy to prevent damage to the circuit on the submount substrate and damage to the base epitaxial layer EB itself. In addition, the energy absorbing layer 700 serves as a bonding force strengthening part that strengthens the bonding force between the micro LED 100 and the submount substrate 200, and during the laser lift-off process, the micro LED 100 and the submount substrate ( 200) makes it smaller than the bonding force between the submount 200 and the micro LED 100 reinforced by the bonding force reinforcing layer 700, and through this, the sapphire substrate can be stably separated.

Next, as shown in FIG. 7 , the micro LED 100 is mounted on the submount substrate 200 and the energy absorbing layer 700 is interposed between the micro LED 100 and the submount substrate 200 . , a laser lift process to remove the sapphire substrate 131 by absorbing a laser, preferably, a UV-A excimer laser, into the gallium nitride-based undoped semiconductor layer between the sapphire substrate 131 and the n-type semiconductor layer 132 . This is done. The laser is irradiated to the gallium nitride-based undoped semiconductor layer 112 through the sapphire substrate 131 . The UV-A laser is absorbed by the undoped semiconductor layer 112 , but is not absorbed by the sapphire substrate 131 . At least a portion of the undoped semiconductor layer 112 is decomposed into liquid-Ga and N ₂ by the laser absorbed by the undoped semiconductor layer 112 , whereby the sapphire substrate 131 is the base of the micro LED 100 . removed from the first side of the epitaxial layer EB.

The energy absorbing layer 700 absorbs the energy of the laser passing through the sapphire substrate between the base epitaxial layer EB and the submount substrate 200 to prevent damage to the circuit or the epitaxial layer by the laser energy. In addition, the use of a square beam rather than a line beam contributes to reducing damage caused by the laser. In this embodiment, after the sapphire substrate 131 is removed, the undoped semiconductor layer 112 of the base epitaxial layer EB is exposed, so that the exposed surface becomes the bonding surface of the wavelength conversion unit described below, but the undoped After the semiconductor layer 112 is further removed, the n-type semiconductor layer 114 is exposed, and the wavelength converter 300 may be coupled to the exposed surface of the n-type semiconductor layer 114 . The undoped semiconductor layer 112 , that is, more specifically, the removal of the U-GaN layer 112 may be performed by an etching process. In addition, before bonding of the wavelength converter, a protective coating layer may be formed on the surface from which the sapphire substrate 131 and/or the undoped half layer 112 are removed to protect the surface to which the wavelength converter is to be bonded in a subsequent process. .

In this embodiment, the entire thickness of the sapphire substrate 131 is removed by a laser lift-off process to form a surface to which the wavelength converter 300 is to be coupled to the base epitaxial layer EB, but the A portion of the thickness may be removed by grinding to form a surface to which the wavelength converter 300 is to be coupled. By reducing the thickness of the sapphire substrate 131 by grinding, only a portion of the sapphire substrate having a fine thickness of approximately 20 to 80 μm remains in the base epitaxial layer EB.

When the entire sapphire substrate 131 is removed, the base epitaxial layer EB itself becomes a base portion B (refer to FIG. 1 ), and when a portion of the thickness of the sapphire substrate 131 remains, the base portion remains. Even the sapphire substrate 131 is included as a part of the base epitaxial layer EB, and the remaining surface of the sapphire substrate 131 becomes a surface to which the wavelength converter 300 is coupled.

Next, as shown in FIG. 8 , on the first surface of the base epitaxial layer EB from which the sapphire substrate 131 is removed, a wavelength conversion unit ( 300) are stacked and combined. The wavelength conversion unit 300 includes a thin film-type quantum dot film 302 having a predetermined thickness, a lower protective layer 301 formed on a bottom surface of the quantum dot film 302 and the quantum dot film 302 . ) and an upper protective layer 303 formed on the upper surface.

The quantum dot film 302 is manufactured in the form of a film using a material in which quantum dot particles capable of converting blue light into red light are mixed with a light-transmitting resin. The lower protective layer 301 and the second protective layer 303 preferably have a hardness value of 5 to 9H, and are preferably formed by coating a PET material on the upper and lower surfaces of the quantum dot film 302 . In particular, the lower protective layer 301 is a portion interposed between the quantum dot film 302 and the epitaxial base 110, and as the thickness of the lower protective layer 301 decreases, the amount of light that spreads out of a target direction is reduced. It is possible to reduce and also reduce the loss of light, thereby increasing the light efficiency. The lower protective layer 301 and the upper protective layer 303 serve to protect quantum dot particles in the quantum dot film 302, which are vulnerable to heat and moisture, from the heat and moisture.

Next, again, as shown in FIG. 1 , a plurality of semi-diffusion patterns 303a are formed on the upper protective layer 303 . Each of the plurality of semi-diffusion patterns 303a is formed on the light exit surface of the upper protective layer 303 to be positioned directly above the plurality of epitaxial cells EC to correspond to each of the plurality of epitaxial cells EC. The semi-diffusion pattern 303a in this embodiment is a Fresnel pattern or a prism pattern that converts light entering while spreading into parallel light and emits it, or a concave lens type semi-diffusion pattern 303b that collects light entering while spreading; FIG. see) can be The semi-diffusion pattern 303a may be formed by laser processing or etching. The time point of forming the semi-diffusion pattern 303a on the upper protective layer 303 is before the wavelength conversion unit 300 is combined with the micro LED 100 and the wavelength conversion unit 300 is combined with the micro LED 100 . All later time points can be considered.

9 is a cross-sectional view for explaining an LED display panel according to another embodiment of the present invention.

Referring to FIG. 9 , the LED display panel according to the present embodiment, as in the previous embodiment, includes a gallium nitride-based base portion (B) having a first surface and a second surface, and a second portion of the base portion (B). A plurality of submount substrates 100 facing two surfaces, arranged in a matrix arrangement on the second surface of the base portion B, and interposed between the base portion B and the submount substrate 100 . and an epitaxial cell EC, wherein the epitaxial base EB and the epitaxial cell EC are part of an epitaxial layer grown on a sapphire substrate, and a micro LED with the sapphire substrate removed. 100) constitutes.

On the other hand, the LED display panel includes a wavelength conversion unit 300 on the first surface of the base portion (B). The wavelength converter 300 includes a quantum dot film 302 having a predetermined thickness, a lower protective layer 301 formed on a bottom surface of the quantum dot film 302 and the quantum dot film 302 . and an upper protective layer 303 formed on the upper surface. In addition, the wavelength conversion unit 300 includes a hole layer 304 formed on the upper surface of the upper protective layer 303 , that is, the light exit surface. The hole layer 304 includes a plurality of holes 3042 formed directly on the plurality of epitaxial cells EC to correspond to the plurality of epitaxial cells EC. In this case, the hole layer 304 is formed of a material that reflects or absorbs light, and can emit light only through the plurality of holes 3042 . Each of the holes 3042 emits light from the corresponding epitaxial cell EC and spreads to other adjacent optical paths among the light passing through the lower passivation layer 301 , the quantum dot film 302 and the upper passivation layer 303 in sequence. It blocks outgoing light and allows only light traveling in the target direction to pass through. Accordingly, it is possible to prevent the light traveling from the corresponding epitaxial EC and traveling through the corresponding optical path from proceeding to the adjacent optical path.

A preferred method for forming the hole layer 304 is to coat a light-opaque material layer on the upper surface of the upper protective layer 303, and then, through an etching process, a plurality of holes 3042 penetrating the light-opaque material layer. ) can be formed. For the light-opaque material layer, a material used for manufacturing a black matrix may be used.

100… … … … … … … … … … … … micro led
200… … … … … … … … … … … … submount board
EC… … … … … … … … … … … … … epitaxial cell
300… … … … … … … … … … … … Wavelength converter
301… … … … … … … … … … … … lower protective layer
302... … … … … … … … … … … … quantum dot film
303… … … … … … … … … … … … upper protective layer
303a, 303b... … … … … … … … anti-diffusion pattern
304… … … … … … … … … … … … single floor
3042… … … … … … … … … … … … hall

Claims (19)

a light-transmitting base portion including a first surface and a second surface opposite thereto;
a submount substrate facing the second surface of the base part;
a plurality of epitaxial cells interposed between the base part and the submount substrate and arranged in a matrix arrangement on a second surface of the base part; and
and a wavelength converter coupled to the first surface of the base part for wavelength-converting the light emitted from the plurality of epitaxial cells,
The wavelength converter includes a quantum dot film and a light-transmitting upper protective layer formed on an upper surface of the quantum dot film, and the upper protective layer has a plurality of epitaxial cells (EC) corresponding to each. It is characterized in that a plurality of anti-spreading patterns are formed,
The base portion, characterized in that the base epitaxial layer, LED display panel. The LED display panel according to claim 1, wherein the plurality of anti-spreading patterns are formed on a light exit surface of the upper protective layer. The LED display panel according to claim 1, wherein each of the plurality of anti-spreading patterns includes a plurality of v-shaped grooves. The LED display panel according to claim 1, wherein the plurality of anti-spreading patterns include a Fresnel lens pattern or a prism lens pattern. The LED display panel according to claim 1, wherein the plurality of anti-spreading patterns comprises a concave pattern for collecting passing light. The LED display panel according to claim 1, further comprising a light-transmitting lower protective layer formed on a bottom surface of the quantum dot film. The LED display panel according to claim 1, wherein the quantum dot film has a thickness of 100 μm or less. The LED display panel according to claim 1, wherein the anti-spreading pattern is formed by etching or laser processing. The method according to claim 1,
The base epitaxial layer is
The base epitaxial layer from which the sapphire substrate is removed, and the wavelength converter is coupled to a surface of the base epitaxial layer from which the sapphire substrate is removed. The method according to claim 1,
The base epitaxial layer is
The LED display panel further comprising a sapphire substrate having a reduced thickness disposed on the first surface of the base epitaxial layer, wherein the wavelength converter is coupled to the reduced thickness surface of the sapphire substrate. a light-transmitting base portion including a first surface and a second surface opposite thereto;
a submount substrate facing the second surface of the base part;
a plurality of epitaxial cells interposed between the base part and the submount substrate and arranged in a matrix arrangement on a second surface of the base part; and
and a wavelength converter coupled to the first surface of the base part for wavelength-converting the light emitted from the plurality of epitaxial cells,
The wavelength converter includes a quantum dot film and a hole layer positioned above the quantum dot film, wherein the hole layer corresponds to the plurality of epitaxial cells and is formed directly on the plurality of epitaxial cells. The LED display panel comprising a hole, wherein the hole layer emits light emitted from the corresponding epitaxial cell and passing through the wavelength conversion unit only through the hole. The LED display panel according to claim 11, wherein the wavelength conversion unit further comprises an upper protective layer having light-transmitting properties between the quantum dot film and the hole layer. The method according to claim 11, wherein the wavelength converter further comprises an upper passivation layer having a light transmittance between the quantum dot film and the hole layer, wherein the hole layer is a plurality of light-opaque material layers coated on the upper surface of the upper passivation layer. An LED display panel, characterized in that it is formed with holes. The LED display panel according to claim 11, further comprising a light-transmitting lower protective layer formed on a bottom surface of the quantum dot film. The LED display panel of claim 11 , wherein the quantum dot film has a thickness of 100 μm or less. The LED display panel of claim 11 , wherein the base part comprises a base epitaxial layer from which a sapphire substrate is removed, and the wavelength converter is coupled to a surface of the base epitaxial layer from which the sapphire substrate is removed. The LED of claim 11 , wherein the base part comprises a reduced-thickness sapphire substrate and a base epitaxial layer formed on the reduced-thickness sapphire substrate, and the wavelength converter is coupled to the reduced-thickness surface of the sapphire substrate. display panel. A sapphire substrate, a gallium nitride-based base epitaxial layer including a first surface in contact with the sapphire substrate and a second surface opposite thereto, and a plurality of epitaxial layers arranged in a matrix on the second surface of the base epitaxial layer Preparing a micro LED including a taxial cell;
preparing a submount substrate;
mounting the micro LED on the submount substrate such that the plurality of epitaxial cells are interposed between the base epitaxial layer and the submount substrate;
completely removing the sapphire substrate or removing a portion of the thickness of the sapphire substrate; and
Comprising the step of combining the wavelength conversion unit for converting the wavelength of the light emitted from the plurality of epitaxial cells to the sapphire substrate from which the base epitaxial layer or the thickness of the sapphire substrate has been partially removed,
A method of manufacturing an LED display panel, characterized in that a plurality of anti-spreading patterns corresponding to each of the plurality of epitaxial cells (EC) are formed in the wavelength converter. A sapphire substrate, a gallium nitride-based base epitaxial layer including a first surface in contact with the sapphire substrate and a second surface opposite thereto, and a plurality of epitaxial layers arranged in a matrix on the second surface of the base epitaxial layer Preparing a micro LED including a taxial cell;
preparing a submount substrate;
mounting the micro LED on the submount substrate such that the plurality of epitaxial cells are interposed between the base epitaxial layer and the submount substrate;
completely removing the sapphire substrate or removing a portion of the thickness of the sapphire substrate; and
Comprising the step of combining the wavelength conversion unit for converting the wavelength of the light emitted from the plurality of epitaxial cells to the sapphire substrate from which the base epitaxial layer or the thickness of the sapphire substrate has been partially removed,
The wavelength converter includes a quantum dot film and a hole layer positioned above the quantum dot film, wherein the hole layer corresponds to the plurality of epitaxial cells and is formed directly on the plurality of epitaxial cells. A method for manufacturing an LED display panel comprising a hole, wherein the hole layer emits light emitted from the corresponding epitaxial cell and passing through the wavelength conversion unit only through the hole.

Images