Patent Description:
Light emitting diodes are widely used as inorganic light sources in various fields, such as display devices, vehicle lamps and general lighting. Light emitting diodes are rapidly replacing existing light sources due to their longer lifetime, lower power consumption, and faster response speed over conventional light sources.

As recently light emitting diodes are being developed to have light weight, thinness, compactness, and miniaturization, so as to be used as backlight sources of various display devices, such as a mobile phone, a color mixing may occur between neighboring light emitting cells.

Document <CIT> discloses a light emitting device including a substrate and a plurality of light emitting cells spaced apart from each other on the substrate, wherein each of the plurality of light emitting cells comprises a first conductive semiconductor layer disposed on the substrate, an active layer disposed on the first conductive semiconductor layer, and a second conductive type semiconductor layer disposed on the active layer, wherein the first conductive type semiconductor layer of the neighbouring light emitting cell is separated into a V-shaped groove.

Light emitting devices constructed according to exemplary embodiments of the invention are capable of preventing color mixing to provide excellent color reproducibility.

A light emitting device according to the invention is disclosed as recited in claim <NUM>.

At least one of the light emitting cells may have a first light emitting part, a second light emitting part, and a third light emitting part vertically stacked one over another.

The light emitting device may further include a common pad, a first pad, a second pad, and a third pad disposed on the at least one light emitting cell, in which the common pad may be electrically connected to the first, second, and third light emitting parts in common, and the first, second, and third pads may be electrically connected to the first, second, and third light emitting parts, respectively.

The light shielding layer may include at least one of Ti, Ni, Al, Ag, Cr, a photoresist, epoxy, PDMS, and a black matrix.

The light shielding layer is disposed on the first surface of the substrate, and the light shielding layer is disposed between the light emitting cells on the first surface of the substrate, and may have a top surface coplanar with a top surface of each of the light emitting cells.

The light emitting device may further include pads disposed on the light shielding layer and electrically coupled with the light emitting cells, respectively.

The light emitting device further includes an insulating layer disposed on the light shielding layer, and may include through electrodes passing through the insulating layer and the light shielding layer, and electrically coupled with the light emitting cells, respectively, and pads disposed on the insulating layer and electrically coupled with the through electrodes.

The light emitting device may further include a pad disposed between the first surface of the substrate and the light emitting cells, and electrically coupled with the light emitting cells.

The substrate may include cell areas in which the plurality of light emitting cells are disposed, and a peripheral area adjacent to the cell areas, the cell areas may include light emitting areas defined by the light shielding layer, respectively, and each light emitting area may be smaller than each cell area.

Portions of the substrate corresponding to the light emitting areas may have a surface roughness.

The concave part may have at least one of substantially a V-shaped structure, substantially a polygonal structure in which the first surface or the second surface of the substrate is opened, and substantially a U-shaped structure.

The light shielding layer may fill at least a portion of the concave part and extends to the first surface or the second surface of the substrate.

In the light emitting device according to exemplary embodiments, by forming a concave part in a substrate including a plurality of light emitting cells and disposing a light shielding layer, which fills at least partially the concave part, light generated from neighboring light emitting cells may be shielded, absorbed, or reflected by the light shielding layer and may not exert an influence to each other. In this manner, a color mixing between adjacent light emitting cells may be prevented, thereby improving the color reproducibility of the light emitting device.

Also, by disposing light shielding layers on both surfaces of the substrate, the light emitting device including the substrate having a thin thickness may be prevented from being damaged by an external shock.

Moreover, by shielding a portion of a cell area where each light emitting cell is disposed, a light emitting area may be formed to be smaller than the cell area. As such, light passing through the light emitting area and emitted from the light emitting cell may be more concentrated, thereby improving the contrast of the light emitting device.

In order to understand the configuration and effect of the disclosure sufficiently, embodiments of the disclosure will be described with reference to the accompanying drawings. However, the disclosure is not limited to the embodiments set forth herein and may be implemented in various forms, and a variety of changes may be added.

Unless otherwise defined, all terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure is a part.

Hereinafter, a light emitting device will be described below with reference to the accompanying drawings through various exemplary embodiments.

<FIG> is a schematic top view of a light emitting device according to an exemplary embodiment, and <FIG> is a cross-sectional view taken along line A-A' of <FIG>. <FIG> is an enlarged view of the concave part <NUM> of the light emitting device illustrated in <FIG>, and <FIG> are modifications of the concave part <NUM> of <FIG> according to exemplary embodiments.

Referring to <FIG>, a light emitting device may include a substrate <NUM> and a plurality of light emitting cells LEC_1 and LEC_2 disposed on the substrate <NUM>.

The substrate <NUM> may be capable of growing a gallium nitride-based semiconductor layer thereon, and may include a sapphire (Al<NUM>O<NUM>), a silicon carbide (SiC), a gallium nitride (GaN), an indium gallium nitride (InGaN), an aluminum gallium nitride (AlGaN), an aluminum nitride (AlN), a gallium oxide (Ga<NUM>O<NUM>), a gallium arsenic (GaAs), or silicon (Si). In some exemplary embodiments, the substrate <NUM> may be flexible, or include a circuit therein.

The substrate <NUM> has a first surface <NUM>, on which the light emitting cells LEC_1 and LEC_2 are disposed, and a second surface <NUM> opposing the first surface <NUM>. The second surface <NUM> of the substrate <NUM> is a light emitting surface of light generated from the light emitting cells LEC_1 and LEC_2.

According to an exemplary embodiment, the substrate <NUM> may have a thickness as thin as possible. This is because the substrate <NUM> may function as a light guide plate, through which light generated from the light emitting cells LEC_1 and LEC_2 may be guided. As such, in order to prevent the substrate <NUM> functioning as a light guide plate, the substrate <NUM> may have a thickness as thin as possible. For example, the substrate <NUM> may have a thickness of about <NUM> to about <NUM>.

By etching the substrate <NUM>, the first surface <NUM> of the substrate <NUM> may be formed with a concave part <NUM>, which extends from the first surface <NUM> to the inside of the substrate <NUM>. The concave part <NUM> includes a vertical part VL extending in a first direction DR1, and a horizontal part HL extending in a second direction DR2 intersecting the first direction DR1. According to the invention, the vertical part VL and the horizontal part HL may cross with each other.

Referring to <FIG>, the concave part <NUM> may have substantially a V-shaped structure, which has two sides converging from the first surface <NUM> of the substrate <NUM> to a point inside the substrate <NUM>. The depth DT of the concave part <NUM> may be about <NUM>/<NUM> to about <NUM>/<NUM> of the thickness DT_S of the substrate <NUM>. For example, when the substrate <NUM> has the thickness DT_S of <NUM> to <NUM>, the concave part <NUM> may have the depth DT of <NUM> to <NUM>. The longest width WT between the two sides of the concave part <NUM> may be about <NUM> to about <NUM>. The angle β between the two sides of the concave part <NUM> may be about <NUM> to about <NUM> degrees.

The concepts are not limited to one particular shape of the concave part <NUM>, and in some exemplary embodiments, the concave part <NUM> may have various structures other than the substantially V-shaped structure. Referring to <FIG>, the concave part <NUM> according to another exemplary embodiment may include two vertical surfaces, which extend from the first surface <NUM> of the substrate <NUM> to the inside of the substrate <NUM> and are parallel to each other, and a horizontal surface connecting the vertical surfaces. In a cross-sectional view, the concave part <NUM> may have substantially an open square structure, in which a side corresponding to the first surface <NUM> of the substrate <NUM> is opened. Referring to <FIG>, the concave part <NUM> according to another exemplary embodiment may include two vertical surfaces, which extend from the first surface <NUM> of the substrate <NUM> to the inside of the substrate <NUM> and are parallel to each other, and two surfaces converging into a point between the two vertical surfaces. In a cross-sectional view, the concave part <NUM> may have substantially an open pentagon structure, in which a side corresponding to the first surface <NUM> of the substrate <NUM> is opened. Referring to <FIG>, the concave part <NUM> according to another exemplary embodiment may extend from the first surface <NUM> of the substrate <NUM> to the inside of the substrate <NUM>, and have a curved surface. In a cross-sectional view, the concave part <NUM> may have substantially a U-shaped structure. It is to be noted that, however, the concepts are not limited to one particular shape of the concave part <NUM>, and in some exemplary embodiments, the concave part <NUM> may have various structures other than those described above.

Referring back to <FIG> and <FIG>, a light shielding layer <NUM> may be disposed at least in a portion of the concave part <NUM>. Between the two neighboring light emitting cells LEC_1 and LEC_2, for example, a first light emitting cell LEC_1 and a second light emitting cell LEC_2, the light shielding layer <NUM> may reflect light generated in the first light emitting cell LEC_1 toward the first light emitting cell LEC_1, or shield or absorb light generated in the first light emitting cell LEC_1, such that light generated in the first light emitting cell LEC_1 does not exert an influence on the second light emitting cell LEC_2. Similarly, the light shielding layer <NUM> may reflect light generated in the second light emitting cell LEC_2 toward the second light emitting cell LEC_2, or shield or absorb light generated in the second light emitting cell LEC_2, such that light generated in the second light emitting cell LEC_2 does not exert an influence on the first light emitting cell LEC_1. For example, the light shielding layer <NUM> may include metal, such as Ti, Ni, Al, Ag and Cr, or may include a material, such as a photoresist, epoxy, PDMS (polydimethylsiloxane), and a black matrix.

Hereinafter, the structure of the light shielding layer <NUM> will be described as being formed in the concave part <NUM> illustrated in <FIG>.

<FIG> are cross-sectional views illustrating the structures of light shielding layers according to exemplary embodiments.

Referring to <FIG>, the light shielding layer <NUM> according to an exemplary embodiment may not completely fill the concave part <NUM>, and may be conformally formed continuously along the inner sidewall of the concave part <NUM>. Referring to <FIG>, the light shielding layer <NUM> according to another exemplary embodiment may not completely fill the concave part <NUM>, may be conformally formed on the inner sidewall of the concave part <NUM>, and may extend onto the first surface <NUM> of the substrate <NUM> to cover at least a portion of the first surface <NUM> of the substrate <NUM>. Referring to <FIG>, the light shielding layer <NUM> according to another exemplary embodiment may completely fill the concave part <NUM>, and may have a top surface coplanar with the first surface <NUM> of the substrate <NUM>. Referring to <FIG>, the light shielding layer <NUM> according to another exemplary embodiment may completely fill the concave part <NUM>, and may extend onto the first surface <NUM> of the substrate <NUM> to cover at least a portion of the first surface <NUM> of the substrate <NUM>.

While the structure of the light shielding layer <NUM> has been described with reference to the structure of the concave part <NUM> illustrated in <FIG>, in some exemplary embodiments, the light shielding layer <NUM> according to exemplary embodiments may be applied to one of the structures of the concave part <NUM> illustrated in <FIG>, and thus, repeated descriptions thereof will be omitted to avoid redundancy.

Referring back to <FIG> and <FIG>, the light emitting cells LEC_1 and LEC_2 may be disposed on the substrate <NUM> and be separated from each other by a predetermined distance. The separation distance of the light emitting cells LEC_1 and LEC_2 may be changed depending on an apparatus to which the light emitting device is to be mounted.

According to an exemplary embodiment, each of the light emitting cells LEC_1 and LEC_2 may have a beam angle α of about <NUM> to about <NUM> degrees. As described above, the separation distance between the light emitting cells LEC_1 and LEC_2 may be changed depending on an apparatus, to which the light emitting cells LEC_1 and LEC_2 are to be mounted. As such, the concave part <NUM>, which is formed with the light shielding layer <NUM>, may be disposed in the substrate <NUM> between the first light emitting cell LEC_1 and the second light emitting cell LEC_2, each of which has the beam angle α of about <NUM> to about <NUM> degrees. The concave part <NUM> may be disposed at a position where light generated in the first light emitting cell LEC_1 (or the second light emitting cell LEC_2) is to be reflected, shielded, or absorbed by the light shielding layer <NUM> not to exert an influence on the second light emitting cell LEC_2 (or the first light emitting cell LEC_1).

The plurality of light emitting cells LEC_1 and LEC_2 disposed on the substrate <NUM> may be a unit, which is to be mounted to a target apparatus at one time. For example, when the light emitting device is formed with four light emitting cells LEC_1 and LEC_2 on the substrate <NUM>, the four light emitting cells LEC_1 and LEC_2 may be mounted to a target apparatus through one process. While four light emitting cells LEC_1 and LEC_2 have been exemplarily described, it is to be noted that the concepts are not limited to one particular number of the light emitting cells LEC_1 and LEC_2 in a light emitting device.

Each of the light emitting cells LEC_1 and LEC_2 may include a first conductivity-type semiconductor layer <NUM>, an active layer <NUM>, a second conductivity-type semiconductor layer <NUM>, and an ohmic layer <NUM>. The first conductivity-type semiconductor layer <NUM> may be an n-type semiconductor layer, which includes a Si-doped gallium nitride-based semiconductor layer. The second conductivity-type semiconductor layer <NUM> may be a p-type semiconductor layer, which includes a Mg-doped gallium nitride-based semiconductor layer. Alternatively, the first conductivity-type semiconductor layer <NUM> may be a p-type semiconductor layer, and the second conductivity-type semiconductor layer <NUM> may be an n-type semiconductor layer. The active layer <NUM> may include a multi-quantum well (MQW), and the composition ratio thereof may be determined to emit light of a desired peak wavelength. As the ohmic layer <NUM>, a transparent conductive oxide (TCO), such as zinc oxide (ZnO), indium tin oxide (ITO), zinc-doped indium tin oxide (ZITO), zinc indium oxide (ZIO), gallium indium oxide (GIO), zinc tin oxide (ZTO), fluorine-doped tin oxide (FTO), gallium-doped zinc oxide (GZO), aluminum-doped zinc oxide (AZO), or others may be used.

Each of the light emitting cells LEC_1 and LEC_2 may further include a first pad <NUM>, which is electrically coupled with the first conductivity-type semiconductor layer <NUM>, and a second pad <NUM>, which is electrically coupled with the ohmic layer <NUM>. Each of the first pad <NUM> and the second pad <NUM> may include at least one of Au, Ti, Ni, Cr, and Al.

<FIG> is a schematic top view of a light emitting device according to another exemplary embodiment, and <FIG> is a cross-sectional view taken along line A-A' of <FIG>.

Referring to <FIG> and <FIG>, the light emitting device according to the illustrated exemplary embodiment is similar to the light emitting device illustrated with reference to <FIG> and <FIG>, however, each of the light emitting cells LEC_1 and LEC_2 according to the illustrated exemplary embodiment includes a first light emitting part LEC_1_1 or LEC_2_1, a second light emitting part LEC_1_2 or LEC_2_2, and a third light emitting part LEC_1_3 or LEC_2_3, which are vertically stacked. As such, the differences of the light emitting device will be mainly described hereinafter in order to avoid redundancy.

When the second surface <NUM> of the substrate <NUM> is a light emitting surface, the first light emitting parts LEC_1_1 and LEC_2_1 may generate light having the shortest wavelength, the second light emitting parts LEC_1_2 and LEC_2_2 may generate light having a wavelength longer than the wavelength of light generated in the first light emitting parts LEC_1_1 and LEC_2_1 and shorter than the wavelength of light generated in the third light emitting parts LEC_1_3 and LEC_2_3, and the third light emitting parts LEC_1_3 and LEC_2_3 may generate light having the longest wavelength. For example, the first light emitting parts LEC_1_1 and LEC_2_1 may generate blue light, the second light emitting parts LEC_1_2 and LEC_2_2 may generate green light, and the third light emitting parts LEC_1_3 and LEC_2_3 may emit red light. However, the concepts are not limited thereto. For example, in some exemplary embodiments, the second light emitting parts LEC_1_2 and LEC_2_2 may emit light having a wavelength shorter than the wavelength of light emitted from the first light emitting parts LEC_1_1 and LEC_2_1. The first light emitting parts LEC_1_1 and LEC_2_1 may include a first n-type semiconductor layer, a first active layer, a first p-type semiconductor layer, and a first ohmic layer. The second light emitting parts LEC_1_2 and LEC_2_2 may include a second n-type semiconductor layer, a second active layer, a second p-type semiconductor layer, and a second ohmic layer. The third light emitting parts LEC_1_3 and LEC_2_3 may include a third n-type semiconductor layer, a third active layer, a third p-type semiconductor layer, and a third ohmic layer. Each of the first n-type semiconductor layer, the second n-type semiconductor layer, and the third n-type semiconductor layer may be a Si-doped gallium nitride-based semiconductor layer. Each of the first p-type semiconductor layer, the second p-type semiconductor layer and the third p-type semiconductor layer may be a Mg-doped gallium nitride-based semiconductor layer. Each of the first active layer, the second active layer, and the third active layer may include a multi-quantum well (MQW), and the composition ratio thereof may be determined to emit light of a desired peak wavelength. Each of the first ohmic layer, the second ohmic layer, and the third ohmic layer may include transparent conductive oxide, such as ZnO, ITO, ZITO, ZIO, GIO, ZTO, FTO, GZO, AZO, or others.

Each of the light emitting cells LEC_1 and LEC_2 may further include a common pad 120a, which electrically couples the first ohmic layer, the second ohmic layer and the third ohmic layer in common, a first pad 120b that is electrically coupled with the first n-type semiconductor layer, a second pad 120c that is electrically coupled with the second n-type semiconductor layer, and a third pad 120d that is electrically coupled with the third n-type semiconductor layer. Alternatively, each of the light emitting cells LEC_1 and LEC_2 may further include a common pad 120a, which electrically couples the first n-type semiconductor layer, the second n-type semiconductor layer, and the third n-type semiconductor layer in common, a first pad 120b that is electrically coupled with the first ohmic layer, a second pad 120c that is electrically coupled with the second ohmic layer, and a third pad 120d that is electrically coupled with the third ohmic layer.

For example, when each of the light emitting cells LEC_1 and LEC_2 includes the first light emitting part LEC_1_1 or LEC_2_1, the second light emitting part LEC_1_2 or LEC_2_2, and the third light emitting part LEC_1_3 or LEC_2_3 which are vertically stacked, the third light emitting part LEC_1_3 or LEC_2_3 may expose at least a portion of the second light emitting part LEC_1_2 or LEC_2_2, and the second light emitting part LEC_1_2 or LEC_2_2 may expose at least a portion of the first light emitting part LEC_1_1 or LEC_2_1, such that the common pad 120a, the first pad 120b, the second pad 120c and the third pad 120d are electrically coupled with the first light emitting part LEC_1_1 or LEC_2_1, the second light emitting part LEC_1_2 or LEC_2_2, and the third light emitting part LEC_1_3 or LEC_2_3. In this case, the third light emitting part LEC_1_3 or LEC_2_3 may be smaller than the second light emitting part LEC_1_2 or LEC_2_2, and the second light emitting part LEC_1_2 or LEC_2_2 may be smaller than the first light emitting part LEC_1_1 or LEC_2_1.

As another example, the first light emitting part LEC_1_1 or LEC_2_1, the second light emitting part LEC_1_2 or LEC_2_2, and the third light emitting part LEC_1_3 or LEC_2_3 may have substantially the same size, and each of the light emitting cells LEC_1 and LEC_2 may further include a plurality of via structures, which electrically couple the common pad 120a, the first pad 120b, the second pad 120c, and the third pad 120d with the first light emitting part LEC_1_1 or LEC_2_1, the second light emitting part LEC_1_2 or LEC_2_2, and the third light emitting part LEC_1_3 or LEC_2_3.

As yet another example, the first light emitting part LEC_1_1 or LEC_2_1 and the second light emitting part LEC_1_2 or LEC_2_2 may have substantially the same size, and the third light emitting part LEC_1_3 or LEC_2_3 may expose at least a portion of the second light emitting part LEC_1_2 or LEC_2_2, such that the common pad 120a, the first pad 120b, the second pad 120c, and the third pad 120d are electrically coupled with the first light emitting part LEC_1_1 or LEC_2_1, the second light emitting part LEC_1_2 or LEC_2_2, and the third light emitting part LEC_1_3 or LEC_2_3. In this case, the first light emitting part LEC_1_1 or LEC_2_1 and the second light emitting part LEC_1_2 or LEC_2_2 may be electrically coupled with the common pad 120a, the first pad 120b, and the second pad 120c by a plurality of via structures.

In the illustrated exemplary embodiment, the concave part <NUM> and the light shielding layer <NUM> described reference with <FIG>, as well as <FIG>, may be similarly employed.

The light emitting device according to the illustrated exemplary embodiment is described as including three vertically stacked light emitting parts, however, the concepts are not limited thereto. In some exemplary embodiments, a light emitting device may include two light emitting parts or more than four light emitting parts, which may be vertically stacked.

Further, each light emitting cell may have light emitting parts that are vertically stacked, but the concepts are not limited thereto, and in some exemplary embodiments, at least one light emitting cell may have a single light emitting part.

The vertically stacked light emitting parts according to the illustrated exemplary embodiment may be applied to light emitting cells of various exemplary embodiments to be described later.

<FIG> is a schematic top view of a light emitting device according to another exemplary embodiment, and <FIG> is a cross-sectional view taken along line A-A' of <FIG>. <FIG> is a schematic top view of a light emitting device according to still another exemplary embodiment, and <FIG> is a cross-sectional view taken along line A-A' of <FIG>.

Referring to <FIG>, <FIG>, <FIG> and <FIG>, a light emitting device may include a substrate <NUM> and a plurality of light emitting cells LEC_1 and LEC_2 disposed on the substrate <NUM>.

The substrate <NUM> may have a first surface <NUM>, on which the light emitting cells LEC_1 and LEC_2 are disposed, and a second surface <NUM> opposing the first surface <NUM>. The first surface <NUM> of the substrate <NUM> may be formed with a concave part <NUM>, which extends from the first surface <NUM> to the inside of the substrate <NUM>. Since the substrate <NUM> and the concave part <NUM> are substantially the same as those described above with reference to <FIG> and <FIG>, repeated descriptions thereof will be omitted.

The first concave part <NUM> according to the illustrated exemplary embodiment may have the structure of the concave part <NUM> described above with reference to <FIG>, without being limited thereto.

The light emitting cells LEC_1 and LEC_2 may be disposed on the first surface <NUM> of the substrate <NUM> and be separated by a predetermined distance. Each of the light emitting cells LEC_1 and LEC_2 may include a first conductivity-type semiconductor layer <NUM>, an active layer <NUM>, a second conductivity-type semiconductor layer <NUM>, and an ohmic layer <NUM>, which are vertically stacked, a first pad <NUM> electrically coupled with the first conductivity-type semiconductor layer <NUM>, and a second pad <NUM> electrically coupled with the ohmic layer <NUM>.

A light shielding layer <NUM> may be disposed to fill the concave part <NUM> and cover the light emitting cells LEC_1 and LEC_2 on the first surface <NUM>. The light shielding layer <NUM> may include an insulating material, such as a photoresist, epoxy, PDMS, and a black matrix.

When light generated in respective active layers <NUM> of the light emitting cells LEC_1 and LEC_2 are emitted in all directions, the light shielding layer <NUM> may be disposed between the light emitting cells LEC_1 and LEC_2 and prevent the lights from being mixed. In particular, since the light shielding layer <NUM> is disposed between the neighboring light emitting cells LEC_1 and LEC_2, for example, a first light emitting cell LEC_1 and a second light emitting cell LEC_2, on the first surface <NUM> of the substrate <NUM>, light generated in the active layer <NUM> of the first light emitting cell LEC_1 may be radiated toward the first surface <NUM> of the substrate <NUM> while not exerting an influence on the second light emitting cell LEC_2, and light generated in the active layer <NUM> of the second light emitting cell LEC_2 may be radiated toward the first surface <NUM> of the substrate <NUM> while not exerting an influence on the first light emitting cell LEC_1. Although light of the first light emitting cell LEC_1 and light of the second light emitting cell LEC_2, which are emitted toward the substrate <NUM>, may be radiated in all directions in the substrate <NUM>, light of the first light emitting cell LEC_1 and light of the second light emitting cell LEC_2 may be reflected, shielded, or absorbed by the light shielding layer <NUM> filling the concave part <NUM>, thereby not exerting an influence on each other.

Further, as the light shielding layer <NUM> fills the concave part <NUM> and cover the light emitting cells LEC_1 and LEC_2, the substrate <NUM> having a thin thickness may be prevented from being broken or damaged by an external shock.

Referring to <FIG> and <FIG>, the top surface of the light shielding layer <NUM> may be substantially coplanar with the top surfaces of the ohmic layers <NUM>. The light shielding layer <NUM> may expose the ohmic layers <NUM>. For example, each first pad <NUM> may be buried by the light shielding layer <NUM>, and may be electrically coupled with a third pad <NUM> disposed on the light shielding layer <NUM> through a through electrode <NUM> passing through the light shielding layer <NUM>. The second pad <NUM> may be disposed on the ohmic layer <NUM>, which is exposed on the light shielding layer <NUM>.

Referring to <FIG> and <FIG>, according to the invention an insulating layer <NUM> is additionally disposed on the light shielding layer <NUM>. The insulating layer <NUM> may include substantially the same material as the light shielding layer <NUM>. Alternatively, the insulating layer <NUM> may include a silicon oxide or a silicon nitride. The light emitting device according to the illustrated exemplary embodiment according to the invention may further include a first through electrode <NUM>, which passes through the insulating layer <NUM> and the light shielding layer <NUM> and is electrically coupled with the first pad <NUM>, a second through electrode <NUM>, which passes through the insulating layer <NUM> and is electrically coupled with the second pad <NUM>, a third pad <NUM>, which is disposed on the insulating layer <NUM> and is brought into electrical contact with the first through electrode <NUM>, and a fourth pad <NUM>, which is disposed on the insulating layer <NUM> and is brought into electrical contact with the second through electrode <NUM>. In this case, when the separation distance between the first pad <NUM> and the second pad <NUM> is different from a separation distance required for an apparatus to which the light emitting device is to be mounted, the separation distance between the first pad <NUM> and the second pad <NUM> may be adjusted by changing the positions of the third pad <NUM>, which is electrically coupled with the first pad <NUM>, and the fourth pad <NUM>, which is electrically coupled with the second pad <NUM>.

Since the substrate <NUM>, the concave part <NUM>, the light shielding layer <NUM>, and the plurality of light emitting cells LEC_1 and LEC_2 illustrated in <FIG>, <FIG>, <FIG> and <FIG> are substantially the same as those of the substrate <NUM>, the concave part <NUM>, the light shielding layer <NUM>, and the plurality of light emitting cells LEC_1 and LEC_2 described above with reference to <FIG> and <FIG>, repeated descriptions thereof will be omitted.

Referring to <FIG> and <FIG>, a light emitting device may include a substrate <NUM> and a plurality of light emitting cells LEC_1 and LEC_2 disposed on the substrate <NUM>.

The substrate <NUM> may have a first surface <NUM>, on which the light emitting cells LEC_1 and LEC_2 are disposed, and a second surface <NUM> opposing the first surface <NUM>. The first surface <NUM> of the substrate <NUM> may be formed with a first concave part <NUM>, which extends from the first surface <NUM> to the inside of the substrate <NUM>. The first concave part <NUM> may include a vertical part VL extending in a first direction DR1, and a horizontal part HL extending in a second direction DR2 substantially perpendicular to the first direction DR1. In some exemplary embodiments, the vertical part VL and the horizontal part HL of the first concave part <NUM> may cross with each other. The second surface <NUM> of the substrate <NUM> may be formed with a second concave part <NUM>, which extends from the second surface <NUM> to the inside of the substrate <NUM>. The second concave part <NUM> may include vertical parts VL extending in the first direction DR1 and are parallel to each other, and horizontal parts HL extending in the second direction DR2 and are parallel to each other. In some exemplary embodiments, the vertical parts VL and the horizontal parts HL of the second concave part <NUM> may cross with each other.

When viewed from the top, the vertical part VL of the first concave part <NUM> may not overlap with the vertical parts VL of the second concave part <NUM>, and the horizontal part HL of the first concave part <NUM> may not overlap with the horizontal parts HL of the second concave part <NUM>. For example, the vertical part VL of the first concave part <NUM> may be disposed between the two neighboring vertical parts VL of the second concave part <NUM>. The horizontal part HL of the first concave part <NUM> may be disposed between the two neighboring horizontal parts HL of the second concave part <NUM>. The second concave part <NUM> may be disposed more adjacent to the light emitting cells LEC_1 and LEC_2 than the first concave part <NUM>.

In a cross-sectional view, the vertical part VL of the first concave part <NUM> may be disposed between the two neighboring vertical parts VL of the second concave part <NUM>. Referring to the part A of <FIG>, the end of the vertical part VL of the first concave part <NUM> and the ends of the vertical parts VL of the second concave part <NUM> may overlap with each other.

While each of the first concave part <NUM> and the second concave part <NUM> is illustrated as having the structure described above with reference to <FIG>, however, the concepts are not limited thereto. For example, in some exemplary embodiments, each of the first concave part <NUM> and the second concave part <NUM> may have the structures of the concave part <NUM> described above with reference to <FIG>, without being limited thereto.

A first light shielding layer <NUM> may fill at least a portion of the first concave part <NUM>. A second light shielding layer <NUM> may fill at least a portion of the second concave part <NUM>. Each of the first light shielding layer <NUM> and the second light shielding layer <NUM> may include metal, such as Ti, Ni, Al, Ag, and Cr, or may include a material, such as a photoresist, epoxy, PDMS, and a black matrix. While each of the first light shielding layer <NUM> and the second light shielding layer <NUM> is illustrated as having the structure of <FIG>, however, the concepts are not limited thereto. For example, in some exemplary embodiments, each of the first light shielding layer <NUM> and the second light shielding layer <NUM> may have the structures of the light shielding layer <NUM> described above with reference to <FIG>, without being limited thereto.

Light generated from the plurality of light emitting cells LEC_1 and LEC_2, for example, a first light emitting cell LEC_1 and a second light emitting cell LEC_2, may be reflected, shielded, or absorbed by the second light shielding layer <NUM>, which is disposed adjacent to the light emitting cells LEC_1 and LEC_2, and light passed through the space excluding the second light shielding layer <NUM> may be reflected, shielded, or absorbed by the first light shielding layer <NUM>. As the second light shielding layer <NUM> and the first light shielding layer <NUM> are disposed between the first light emitting cell LEC_1 and the second light emitting cell LEC_2, light generated in the first light emitting cell LEC_1 may not exert an influence on the second light emitting cell LEC_2, and light generated in the second light emitting cell LEC_2 may not exert an influence on the first light emitting cell LEC_1. In this manner, it is possible to prevent mixture of light generated from a plurality of light emitting cells.

Since the substrate <NUM>, the first concave part <NUM>, the second concave part <NUM>, the first light shielding layer <NUM>, the second light shielding layer <NUM> and the plurality of light emitting cells LEC_1 and LEC_2 illustrated in <FIG> and <FIG> are substantially the same as those of the substrate <NUM>, the concave part <NUM>, the light shielding layer <NUM> and the plurality of light emitting cells LEC_1 and LEC_2 described above with reference to <FIG> and <FIG>, repeated descriptions thereof will be omitted.

<FIG> and <FIG> are schematic top views of a light emitting device according to another exemplary embodiment, and <FIG> is a cross-sectional view taken along the A-A' of <FIG> is a top view obtained when viewing the light emitting device from one side, for example, a position where pads are disposed, and <FIG> is a top view obtained when viewing the light emitting device from the opposing side, for example, a light emitting surface.

The substrate <NUM> may have a first surface <NUM>, on which the light emitting cells LEC_1 and LEC_2 are disposed, and a second surface <NUM> opposing the first surface <NUM>. A first concave part <NUM> may be formed in the first surface <NUM> of the substrate <NUM>, and a second concave part <NUM> may be formed in the second surface <NUM> of the substrate <NUM>. The first concave part <NUM> may include a vertical part VL and a horizontal part HL, and the second concave part <NUM> may include vertical parts VL and horizontal parts HL. The light emitting cells LEC_1 and LEC_2 may be disposed on the first surface <NUM> of the substrate <NUM>, and each of the light emitting cells LEC_1 and LEC_2 may include a first conductivity-type semiconductor layer <NUM>, an active layer <NUM>, a second conductivity-type semiconductor layer <NUM>, and an ohmic layer <NUM>. The light emitting device may further include first pads <NUM> electrically coupled with first conductivity-type semiconductor layers <NUM> of the light emitting cells LEC_1 and LEC_2, and second pads <NUM> electrically coupled with the ohmic layers <NUM> of the light emitting cells LEC_1 and LEC_2. Since the substrate <NUM>, the first concave part <NUM>, the second concave part <NUM>, the light emitting cells LEC_1 and LEC_2, the first pads <NUM>, and the second pads <NUM> are substantially the same as the substrate <NUM>, the first concave part <NUM>, the second concave part <NUM>, the light emitting cells LEC_1 and LEC_2, the first pads <NUM>, and the second pads <NUM> described above with reference to <FIG> and <FIG>, repeated descriptions thereof will be omitted.

The substrate <NUM> may include cell areas CA, where the light emitting cells LEC_1 and LEC_2 are positioned, and a peripheral area PA excluding the cell areas CA. Each of the cell areas CA may include a light emitting area EA, through which light is emitted. The light emitting area EA may be smaller than the cell area CA.

Referring to <FIG> and <FIG>, a first light shielding layer <NUM>, which fills at least a portion of the first concave part <NUM>, may be provided on the first surface <NUM> of the substrate <NUM>. The first light shielding layer <NUM> may be disposed to cover a portion of the peripheral area PA, so as to expose the cell areas CA.

Referring to <FIG> and <FIG>, a second light shielding layer <NUM>, which fills at least a portion of the second concave part <NUM>, may be provided on the second surface <NUM> of the substrate <NUM>. The second light shielding layer <NUM> may cover the peripheral area PA and partially cover the cell areas CA, thereby exposing light emitting areas EA. For example, when each cell area CA has a quadrangular structure when viewed from the top, each light emitting area EA may have a quadrangular structure concentric with each cell area CA with a smaller size than the corresponding cell area CA.

While each of the first light shielding layer <NUM> and the second light shielding layer <NUM> is illustrated as having the structure described above with reference to <FIG>, however, in some exemplary embodiments, the first light shielding layer <NUM> may have at least one of the structures of the first light shielding layer <NUM> illustrated in <FIG>, <FIG>, without being limited thereto.

In this case, light emitted from the light emitting cells LEC_1 and LEC_2 are radiated through the light emitting areas EA having a size smaller than each of the light emitting cells LEC_1 and LEC_2, and a portion of the substrate <NUM> excluding the light emitting areas EA is shielded by the second light shielding layer <NUM>. As such, light emitted from the light emitting cells LEC_1 and LEC_2 may be emitted by being concentrated in the light emitting areas EA. In this manner, the light emitting device may have an excellent contrast.

In addition, although the thickness of the substrate <NUM> is thin, because the first light shielding layer <NUM> and the second light shielding layer <NUM> are formed on the first surface <NUM> and the second surface <NUM> of the substrate <NUM>, respectively, it is possible to prevent the substrate <NUM> from being broken by an external shock and prevent the light emitting device from being damaged. Also, when the substrate <NUM> includes a glass material and the second surface <NUM> of the substrate <NUM> is a light extraction surface, a phenomenon that external light is reflected by the second surface <NUM>, which function as the light extraction surface, and cause an unintended external object to be recognized may be prevented by the second light shielding layer <NUM> formed on the second surface <NUM>.

According to an exemplary embodiment, rough structures PT may be formed on the second surface <NUM> of the substrate <NUM> corresponding to the light emitting areas EA, by using a roughing process. As each of the light emitting areas EA has the rough structure PT, light emitted through each light emitting area EA, which is smaller than each of the light emitting cells LEC_1 and LEC_2, may be scattered by the rough structure PT, such that the light extraction effect of the light emitting device may be improved. In some exemplary embodiments, the rough structures PT corresponding to the light emitting areas EA on the second surface <NUM> of the substrate <NUM> may be omitted.

Since the substrate <NUM>, the first concave part <NUM>, the second concave part <NUM>, the first light shielding layer <NUM>, the second light shielding layer <NUM>, and the plurality of light emitting cells LEC_1 and LEC_2 illustrated in <FIG> are substantially the same as those for the substrate <NUM>, the concave part <NUM>, the light shielding layer <NUM>, and the plurality of light emitting cells LEC_1 and LEC_2 described above with reference to <FIG> and 2A to 2D, repeated descriptions thereof will be omitted.

<FIG> and <FIG> are schematic top views of a light emitting device according to another exemplary embodiment, and <FIG> is a cross-sectional view taken along line A-A' of <FIG> is a top view obtained when viewing the light emitting device from one side, for example, a position where pads are disposed, and <FIG> is a top view obtained when viewing the light emitting device from the opposing side, for example, a light emitting surface.

The substrate <NUM> may have a first surface <NUM>, on which the light emitting cells LEC_1 and LEC_2 are disposed, and a second surface <NUM> opposing the first surface <NUM>. The substrate <NUM> may include cell areas CA, where the light emitting cells LEC_1 and LEC_2 are positioned, and a peripheral area PA excluding the cell areas CA. Each of the cell areas CA may include a light emitting area EA. The light emitting area EA may be smaller than the cell area CA. A first concave part <NUM> may be formed in the first surface <NUM> of the substrate <NUM>, and a second concave part <NUM> may be formed in the second surface <NUM> of the substrate <NUM>. The first concave part <NUM> may include a vertical part VL and a horizontal part HL, and the second concave part <NUM> may include vertical parts VL and horizontal parts HL.

Since the substrate <NUM>, the first concave part <NUM>, and the second concave part <NUM> are substantially the same as the substrate <NUM>, the first concave part <NUM>, and the second concave part <NUM> described above with reference to <FIG>, repeated descriptions thereof will be omitted.

The light emitting device may further include a first light shielding layer <NUM>, which is formed in the first concave part <NUM>, and a second light shielding layer <NUM>, which is formed in the second concave part <NUM>. The first light shielding layer <NUM> may fill at least a portion of the first concave part <NUM>, and may have the structure illustrated in <FIG>. The second light shielding layer <NUM> may fill at least a portion of the second concave part <NUM>, and may have the structure illustrated in <FIG>.

While the first light shielding layer <NUM> and the second light shielding layer <NUM> are illustrated as having the structure illustrated in <FIG>, however, the concepts are not limited thereto. For example, in some exemplary embodiments, the first light shielding layer <NUM> and the second light shielding layer <NUM> may have at least one of the structures of the first light shielding layer <NUM> illustrated in <FIG>, <FIG>, without being limited thereto.

According to an exemplary embodiment, the first light shielding layer <NUM> may include metal, such as Ti, Ni, Al, Ag, and Cr, or may include a material, such as a photoresist, epoxy, PDMS, and a black matrix. The second light shielding layer <NUM> may include metal, such as Ti, Ni, Al, Ag, and Cr.

Each of the light emitting cells LEC_1 and LEC_2 may include a first conductivity-type semiconductor layer <NUM>, an active layer <NUM>, a second conductivity-type semiconductor layer <NUM>, and an ohmic layer <NUM>. The first conductivity-type semiconductor layer <NUM> may be an n-type semiconductor layer, and the second conductivity-type semiconductor layer <NUM> may be a p-type semiconductor layer. Alternatively, the first conductivity-type semiconductor layer <NUM> may be a p-type semiconductor layer, and the second conductivity-type semiconductor layer <NUM> may be an n-type semiconductor layer.

According to an exemplary embodiment, the first conductivity-type semiconductor layer <NUM> of each of the light emitting cells LEC_1 and LEC_2 may be electrically coupled with the second light shielding layer <NUM> through a through electrode VE. As described above, since the second light shielding layer <NUM> includes metal, such as Ti, Ni, Al, Ag and Cr, the second light shielding layer <NUM> may function as an electrode. More particularly, current may be supplied to first conductivity-type semiconductor layers <NUM> through the second light shielding layer <NUM>, and the second light shielding layer <NUM> may function as a common pad, which supplies current to the first conductivity-type semiconductor layers <NUM>.

According to an exemplary embodiment, since light generated from the two neighboring light emitting cells LEC_1 and LEC_2, for example, a first light emitting cell LEC_1 and a second light emitting cell LEC_2, may not be mixed with each other due to the presence of the first light shielding layer <NUM> and the second light shielding layer <NUM>, the light emitting device may have excellent color reproducibility. Moreover, because the first light shielding layer <NUM> is disposed on the first surface <NUM> of the substrate <NUM> and the second light shielding layer <NUM> is disposed on the second surface <NUM> of the substrate <NUM>, it is possible to prevent the substrate <NUM> having a thin thickness from being damaged by an external shock. Further, as the second light shielding layer <NUM> includes metal, the second light shielding layer <NUM> may function as a common pad, which supplies current to the first conductivity-type semiconductor layers <NUM>.

According to an exemplary embodiment, since the second light shielding layer <NUM> selectively exposes the light emitting areas EA and shields the other portion as illustrated in <FIG>, light generated from the light emitting cells LEC_1 and LEC_2 may be emitted by passing through the light emitting areas EA, each of which is smaller than the corresponding cell area CA. As such, light generated from the light emitting cells LEC_1 and LEC_2 may be emitted by being concentrated in the light emitting areas EA. In this manner, the light emitting device may have an excellent contrast.

The light emitting device may further include pads <NUM>, which are respectively disposed on ohmic layers <NUM>. Each of the pads <NUM> may include metal, such as Ti, Ni, Al, Ag, and Cr. The pads <NUM> may provide current to the second conductivity-type semiconductor layers <NUM> through the ohmic layers <NUM>.

In some exemplary embodiments, rough structures PT may be formed in the light emitting areas EA of the second surface <NUM> of the substrate <NUM>, which are exposed by the second light shielding layer <NUM>. In this manner, light emitted through each light emitting area EA, which is smaller than each of the light emitting cells LEC_1 and LEC_2, may be scattered by the rough structure PT, such that the light emitting device may have an improved light extraction effect.

Since the substrate <NUM>, the first concave part <NUM>, the second concave part <NUM>, the first light shielding layer <NUM>, the second light shielding layer <NUM>, and the plurality of light emitting cells LEC_1 and LEC_2 illustrated in <FIG> are substantially the same as those of the substrate <NUM>, the first concave part <NUM>, the second concave part <NUM>, the first light shielding layer <NUM>, the second light shielding layer <NUM>, and the plurality of light emitting cells LEC_1 and LEC_2 described above with reference to <FIG>, repeated descriptions thereof will be omitted.

<FIG> and <FIG> are schematic top views of a light emitting device according to an exemplary embodiment, and <FIG> is a cross-sectional view taken along line A-A' of <FIG> is a top view obtained when viewing the light emitting device from one side, for example, a position where pads are disposed, and <FIG> is a top view obtained when viewing the light emitting device from the opposing side, for example, a light emitting surface.

Referring to <FIG>, a light emitting device may include a substrate <NUM>, a plurality of light emitting cells LEC_1 and LEC_2 disposed on a first surface <NUM> of the substrate <NUM>, a first pad <NUM> and second pads <NUM> disposed on the first surface <NUM> of the substrate <NUM> and are electrically coupled with the plurality of light emitting cells LEC_1 and LEC_2, and a light shielding layer <NUM> disposed on a second surface <NUM> of the substrate <NUM> opposing the first surface <NUM>.

The substrate <NUM> may include cell areas CA, where the light emitting cells LEC_1 and LEC_2 are disposed, and a peripheral area PA excluding the cell areas CA. Each of the cell areas CA may include a light emitting area EA, which is smaller than the corresponding cell area CA.

Each of the light emitting cells LEC_1 and LEC_2 may include a first conductivity-type semiconductor layer <NUM>, an active layer <NUM>, a second conductivity-type semiconductor layer <NUM> and an ohmic layer <NUM>, which are vertically stacked. The first pad <NUM> may electrically couple first conductivity-type semiconductor layers <NUM> in common. The first pad <NUM> may supply current to the first conductivity-type semiconductor layers <NUM>. For example, the first pad <NUM> may include metal, such as Ti, Ni, Al, Ag, Cr, Au and Cu.

According to an exemplary embodiment, the first pad <NUM> may be disposed between the first conductivity-type semiconductor layers <NUM> and the first surface <NUM> of the substrate <NUM>. The first pad <NUM> may be disposed on the center portion of the substrate <NUM>, cover portions of the cell areas CA, and expose respective light emitting areas EA. Light generated from the light emitting cells LEC_1 and LEC_2 may be shielded, reflected, or absorbed at the portions of the cell areas CA covered by the first pad <NUM>, and may be radiated toward the substrate <NUM> through the light emitting areas EA. As such, the first pad <NUM> may function as a light shielding layer.

When viewed from the top, the substrate <NUM> may have substantially a quadrangular structure, and the light emitting cells LEC_1 and LEC_2 may be disposed at respective corners of the substrate <NUM> while being separated from the edges of the substrate <NUM>. For example, the first pad <NUM> may have substantially a cross-shaped structure, which exposes the respective corners of the substrate <NUM>. In this case, the first pad <NUM> may expose not only the light emitting areas EA but also portions of the substrate <NUM> disposed between the light emitting areas EA and the respective corners of the substrate <NUM>. As another example, the first pad <NUM> may have substantially a quadrangular structure including openings, which expose the light emitting areas EA. In this case, the first pad <NUM> may selectively expose only the light emitting areas EA.

The respective second pads <NUM> may be disposed while being brought into electrical contact with the respective ohmic layers <NUM>. The second pads <NUM> may supply current to second conductivity-type semiconductor layers <NUM> through the ohmic layers <NUM>.

The second surface <NUM> of the substrate <NUM> may include a concave part <NUM>, which is recessed from the second surface <NUM> to the inside of the substrate <NUM>. The concave part <NUM> may include vertical parts VL extending in a first direction DR1 and are parallel to each other, and horizontal parts HL extending in a second direction DR2 and are parallel to each other. In some exemplary embodiments, the vertical parts VL and the horizontal parts HL of the concave part <NUM> may cross with each other.

While the concave part <NUM> according to the illustrated exemplary embodiment is described as having the structure described above with reference to <FIG>, however, in some exemplary embodiments, the concave part <NUM> may have one of the structures of the concave part <NUM> described above with reference to <FIG>, without being limited thereto.

The light shielding layer <NUM> may be disposed on the second surface <NUM> of the substrate <NUM>. According to an exemplary embodiment, the light shielding layer <NUM> may include a first portion 145_1 that fills at least a portion of the concave part <NUM>, and second portions 145_2 disposed at corners on the second surface <NUM> of the substrate <NUM>, respectively, to expose the light emitting areas EA.

While the first portion 145_1 of the light shielding layer <NUM> according to the illustrated exemplary embodiment is described as having the structure of <FIG>, however, in some exemplary embodiments, the light shielding layer <NUM> may have one the structures of the light shielding layer <NUM> described above with reference to <FIG>, without being limited thereto.

The second portions 145_2 of the light shielding layer <NUM> may be disposed in correspondence to portions of the substrate <NUM> where the first pad <NUM> is not formed, and may expose the light emitting areas EA. Each of the second portions 145_2 may have substantially an L-shaped structure in a plan view. According to another exemplary embodiment, as illustrated in <FIG>, the light shielding layer <NUM> may have a structure, which selectively exposes the light emitting areas EA and covers the entirety of the other portion.

Light generated from the light emitting cells LEC_1 and LEC_2 may be reflected, shielded, or absorbed by the first portion 145_1 of the light shielding layer <NUM>. As such, light of the light emitting cells LEC_1 and LEC_2 may be prevented from being mixed, thereby improving the color reproducibility of the light emitting device.

The second portions 145_2 of the light shielding layer <NUM> may cover portions of the peripheral area PA and the cell areas CA that not covered by the first pad <NUM>, thereby defining the light emitting areas EA. Each of the light emitting areas EA may be smaller than each of the cell areas CA. As such, light generated from the light emitting cells LEC_1 and LEC_2 may be emitted by being selectively concentrated through the light emitting areas EA. Accordingly, the light emitting device may exhibit an excellent contrast.

Since the substrate <NUM>, the concave part <NUM>, the light shielding layer <NUM>, and the plurality of light emitting cells LEC_1 and LEC_2 illustrated in <FIG> are substantially the same as those for the substrate <NUM>, the second concave part <NUM>, the second light shielding layer <NUM>, and the plurality of light emitting cells LEC_1 and LEC_2 described above with reference to <FIG>, repeated descriptions thereof will be omitted.

<FIG> and <FIG> are schematic top views of a light emitting device according to another exemplary embodiment, and <FIG> is a cross-sectional view taken along line A-A' of <FIG> is a top view obtained when viewing the light emitting device from one side, and <FIG> is a top view obtained when viewing the light emitting device from the opposing side.

Referring to <FIG>, a light emitting device may include a substrate <NUM>, a plurality of light emitting cells LEC_1 and LEC_2 disposed on a first surface <NUM> of the substrate <NUM>, first pads <NUM> and a second pad <NUM> disposed on the first surface <NUM> of the substrate <NUM> and are electrically coupled with the light emitting cells LEC_1 and LEC_2, and a light shielding layer <NUM> disposed on a second surface <NUM> of the substrate <NUM> opposing the first surface <NUM>.

The substrate <NUM> may include cell areas CA, where the light emitting cells LEC_1 and LEC_2 are disposed, and a peripheral area PA excluding the cell areas CA. Each of the cell areas CA may include a light emitting area EA, which is smaller than each cell area CA.

When viewed from the top, the substrate <NUM> may have substantially a quadrangular structure, and the light emitting cells LEC_1 and LEC_2 may be disposed at respective corners of the substrate <NUM> by being separated from the edges of the substrate <NUM>.

Each of the light emitting cells LEC_1 and LEC_2 may include a first conductivity-type semiconductor layer <NUM>, an active layer <NUM>, a second conductivity-type semiconductor layer <NUM>, and an ohmic layer <NUM>, which are vertically stacked. The first pads <NUM> may be electrically coupled with respective first conductivity-type semiconductor layer <NUM>. The first pads <NUM> may supply current to the respective first conductivity-type semiconductor layer <NUM>. For example, the first pads <NUM> may include metal, such as Ti, Ni, Al, Ag, Cr, Au, and Cu.

According to an exemplary embodiment, each of the first pads <NUM> may be disposed between the corresponding first conductivity-type semiconductor layer <NUM> and the first surface <NUM> of the substrate <NUM>. The first pads <NUM> may be disposed at the respective corners of the substrate <NUM> to expose light emitting areas EA. For example, each of the first pads <NUM> may have substantially an L-shaped structure in a plan view.

The first pads <NUM> may cover portions of the cell areas CA and expose the light emitting areas EA. Light generated from the light emitting cells LEC_1 and LEC_2 may be shielded, reflected, or absorbed at portions of the substrate <NUM> covered by the first pads <NUM>, and may be radiated toward the substrate <NUM> through the light emitting areas EA. As such, each of the first pads <NUM> may function as a light shielding layer.

The second pad <NUM> may be disposed at the center portion of the substrate <NUM>. The second pad <NUM> may be electrically coupled with the ohmic layers <NUM> in common, and may extend to the first surface <NUM> of the substrate <NUM>. According to an exemplary embodiment, the light emitting device may further include a passivation layer PVT, which is disposed between the first conductivity-type semiconductor layers <NUM>, active layers <NUM>, second conductivity-type semiconductor layers <NUM>, the ohmic layers <NUM>, the substrate <NUM>, and the second pad <NUM>. The second pad <NUM> may include metal, such as Ti, Ni, Al, Ag, Cr, Au, and Cu, and the passivation layer PVT may include an insulating material, such as SiO<NUM> and SiN. The passivation layer PVT may include openings, which expose at least portions of the ohmic layers <NUM>. The second pad <NUM> may be electrically coupled with the ohmic layers <NUM> through the openings.

According to an exemplary embodiment, the second pad <NUM> may cover the top portions of the respective ohmic layers <NUM>. In this case, some of the light emitted in all directions from the respective active layers <NUM> may be reflected toward the substrate <NUM> by the second pad <NUM>.

According to an exemplary embodiment, the respective first pads <NUM> may overlap with portions of the second pad <NUM>. The respective first pads <NUM> may cover the portions of the cell areas CA and expose the light emitting areas EA, and the second pad <NUM> may cover the cell areas CA including the light emitting areas EA.

The light shielding layer <NUM> may fill at least a portion of a concave part <NUM>, which is formed in the second surface <NUM> of the substrate <NUM>. While the concave part <NUM> is illustrated as having the structure described above with reference to <FIG>, however, in some exemplary embodiments, the concave part <NUM> may have one the structures of the concave part <NUM> described above with reference to <FIG> and <FIG>, without being limited thereto. Also, while the light shielding layer <NUM> is illustrated as having the structure of <FIG>, however, in some exemplary embodiments, the light shielding layer <NUM> may have one of the structures of the light shielding layer <NUM> described above with reference to <FIG>, <FIG> and <FIG>, without being limited thereto.

According to an exemplary embodiment, the light shielding layer <NUM> may fill the concave part <NUM> while covering a portion of the second surface <NUM> of the substrate <NUM>. The light shielding layer <NUM> may be disposed at the center area of the second surface <NUM> of the substrate <NUM>. The light shielding layer <NUM> may be disposed to expose the light emitting areas EA and correspond to an area where the first pads <NUM> are not disposed. For example, the light shielding layer <NUM> may have substantially a cross-shaped structure to expose the light emitting areas EA. The light shielding layer <NUM> may include metal, such as Ti, Ni, Al, Ag, and Cr, or may include a material, such as a photoresist, epoxy, PDMS, and a black matrix.

Light generated from the light emitting cells LEC_1 and LEC_2 may be reflected, shielded, or absorbed by the light shielding layer <NUM>, and light of the light emitting cells LEC_1 and LEC_2 may be prevented from being mixed, thereby improving the color reproducibility of the light emitting device. The light shielding layer <NUM> may cover portions of the peripheral area PA and the cell areas CA, which are not covered by the first pads <NUM>, thereby defining the light emitting areas EA. Each of the light emitting areas EA may be smaller than each cell area CA. As such, light generated from the light emitting cells LEC_1 and LEC_2 may be emitted by being selectively concentrated through the light emitting areas EA. In this manner, the light emitting device may exhibit excellent contrast.

The light emitting device may further include first solders SD1, which are electrically coupled with the first pads <NUM>, respectively, on the first pads <NUM>, and a second solder SD2, which is electrically coupled with the second pad <NUM> on the second pad <NUM>.

Since the substrate <NUM>, the concave part <NUM>, the light shielding layer <NUM>, and the plurality of light emitting cells LEC_1 and LEC_2 illustrated in <FIG> are substantially the same as those of the substrate <NUM>, the concave part <NUM>, the light shielding layer <NUM>, and the plurality of light emitting cells LEC_1 and LEC_2 described above with reference to <FIG>, repeated descriptions thereof will be omitted.

<FIG> is a schematic top view of a light emitting device according to another exemplary embodiment, and <FIG> is a cross-sectional view taken along line A-A' of <FIG> is a top view obtained when viewing the light emitting device from one side, for example, a position where pads are disposed. Since a top view obtained when viewing the light emitting device from the opposing side, for example, a light emitting surface, is substantially the same as <FIG>, the top view of the opposing side may be referenced to <FIG>.

Referring to <FIG>, <FIG> and <FIG>, a light emitting device may include a substrate <NUM>, a plurality of light emitting cells LEC_1 and LEC_2 disposed on a first surface <NUM> of the substrate <NUM>, first pads <NUM> and second pads <NUM> disposed on the first surface <NUM> of the substrate <NUM> and are electrically coupled with the light emitting cells LEC_1 and LEC_2, a first light shielding layer <NUM> disposed on the first surface <NUM> of the substrate <NUM> between the light emitting cells LEC_1 and LEC_2, and a second light shielding layer <NUM> disposed on a second surface <NUM> of the substrate <NUM> opposing the first surface <NUM>.

Each of the light emitting cells LEC_1 and LEC_2 may include a first conductivity-type semiconductor layer <NUM>, an active layer <NUM>, a second conductivity-type semiconductor layer <NUM>, and an ohmic layer <NUM>, which are vertically stacked. The first pads <NUM> may be disposed between the corresponding first conductivity-type semiconductor layer <NUM> and the substrate <NUM>. Each of the first pads <NUM> may be brought into electrical contact with the corresponding first conductivity-type semiconductor layer <NUM>. According to an exemplary embodiment, the substrate <NUM> may have substantially a quadrangular structure. When the light emitting cells LEC_1 and LEC_2 are respectively disposed at the corners of the substrate <NUM>, the first pads <NUM> may be respectively disposed at the corners, and may respectively expose light emitting areas EA. Each of the first pads <NUM> may include metal, such as Ti, Ni, Al, Ag, Cr, Au, and Cu.

The second pads <NUM> may be electrically coupled with the corresponding ohmic layer <NUM>. In some exemplary embodiments, a passivation layer PVT may be further included, which is disposed between the first conductivity-type semiconductor layers <NUM>, active layers <NUM>, second conductivity-type semiconductor layers <NUM>, the ohmic layers <NUM>, the substrate <NUM>, and the second pads <NUM>. Each of the second pads <NUM> may include metal, such as Ti, Ni, Al, Ag, Cr, Au, and Cu, and the passivation layer PVT may include an insulating material, such as SiO<NUM> and SiN. The passivation layer PVT may include openings, which respectively expose at least portions of the ohmic layers <NUM>. The respective second pads <NUM> may be electrically coupled with the respective ohmic layers <NUM> through the openings.

According to an exemplary embodiment, the respective second pads <NUM> may cover the top portions of the respective ohmic layers <NUM>. In this case, some of lights emitted in all directions from the respective active layers <NUM> may be reflected toward the substrate <NUM> by the second pads <NUM>.

According to an exemplary embodiment, the respective first pads <NUM> may overlap with the respective second pads <NUM>. The respective first pads <NUM> may cover portions of the cell areas CA and expose the light emitting areas EA, and the respective second pads <NUM> may cover the respective cell areas CA including the respective light emitting areas EA.

The first light shielding layer <NUM> may fill at least a portion of a first concave part <NUM>, which is formed in the first surface <NUM> of the substrate <NUM>. For example, the first light shielding layer <NUM> may include metal, such as Ti, Ni, Al, Ag, and Cr, or may include a material, such as a photoresist, epoxy, PDMS, and a black matrix.

While the first concave part <NUM> is illustrated as having the structure described above with reference to <FIG>, however, in some exemplary embodiments, the concave part <NUM> may have one the structures of the first concave part <NUM> described above with reference to <FIG>, without being limited thereto. Also, while the first light shielding layer <NUM> is illustrated as having the structure of <FIG>, however, in some exemplary embodiments, the first light shielding layer <NUM> may have one of the structures of the light shielding layer <NUM> described above with reference to <FIG>, <FIG> and <FIG>, without being limited thereto.

Since the second light shielding layer <NUM> is substantially the same as the second light shielding layer <NUM> described above with reference to <FIG>, repeated descriptions thereof will be omitted.

Light generated from the light emitting cells LEC_1 and LEC_2 may be reflected, shielded, or absorbed by the first light shielding layer <NUM> and the second light shielding layer <NUM>, and thus, light of the light emitting cells LEC_1 and LEC_2 may be prevented from being mixed, thereby improving the color reproducibility of the light emitting device. The second light shielding layer <NUM> may cover portions of the peripheral area PA and the cell areas CA, which are not covered by the first pads <NUM>, thereby defining the respective light emitting areas EA. Each of the light emitting areas EA may be smaller than each cell area CA. As such, light generated from the light emitting cells LEC_1 and LEC_2 may be emitted by being selectively concentrated through the light emitting areas EA. Therefore, the light emitting device may exhibit an excellent contrast.

Since the substrate <NUM>, the first concave part <NUM>, the second concave part <NUM>, the first light shielding layer <NUM>, the second light shielding layer <NUM>, the plurality of light emitting cells LEC_1 and LEC_2, the first pads <NUM>, and the second pads <NUM> illustrated in <FIG> and <FIG> are substantially the same as those for the substrate <NUM>, the first concave part <NUM>, the second concave part <NUM>, the first light shielding layer <NUM>, the second light shielding layer <NUM>, the plurality of light emitting cells LEC_1 and LEC_2, the first pads <NUM>, and the second pads <NUM> described above with reference to FIGS. 6A to 6C, repeated descriptions thereof will be omitted.

Hereinafter, a method for manufacturing a light emitting device according to an exemplary embodiment will be described. In particular, a method for manufacturing the light emitting device illustrated in <FIG> will be described as an example.

<FIG> are schematic top views illustrating a method for manufacturing a light emitting device according to an exemplary embodiment, and <FIG> are cross-sectional views taken along the lines A-A' of <FIG>.

Referring to <FIG> and <FIG>, cells may be formed on a first surface <NUM> of a substrate <NUM>.

A first conductivity-type semiconductor layer <NUM>, an active layer <NUM>, and a second conductivity-type semiconductor layer <NUM> may be formed on the first surface <NUM> of the first substrate <NUM> by using a growing method, such as metal organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), hydride vapor phase epitaxy (HVPE), and metal-organic chloride (MOC).

Then, an ohmic layer <NUM> may be formed on the second conductivity-type semiconductor layer <NUM> by using a deposition process.

By etching the ohmic layer <NUM>, the second conductivity-type semiconductor layer <NUM>, and the active layer <NUM>, mesa structures exposing portions of the first conductivity-type semiconductor layer <NUM> may be formed. After forming the mesa structures, the mesa structures may have sloped sidewalls through a reflow process, for example.

By patterning the first conductivity-type semiconductor layer <NUM>, a plurality of light emitting cells LEC_1 and LEC_2 may be formed.

In some exemplary embodiments, in order to form light emitting cells LEC_1 and LEC_2, after an ohmic layer <NUM> is formed on a first surface of a substrate <NUM>, semiconductor layers formed on other substrates may be sequentially bonded to the ohmic layer <NUM>, which may then be patterned to form the light emitting cells each including a first light emitting part LEC_1_1 or LEC_2_1, a second light emitting part LEC_1_2 or LEC 2_2, and a third light emitting part LEC_1_3 or LEC_2_3.

Referring to <FIG> and <FIG>, first pads <NUM> electrically coupled with first conductivity-type semiconductor layers <NUM>, respectively, exposed by the mesa structures, and second pads <NUM> electrically coupled with ohmic layers <NUM>, respectively, may be formed.

A pad layer may be conformally formed on the substrate <NUM>, which is formed with the plurality of light emitting cells LEC_1 and LEC_2, through a deposition process generally known in the art. The pad layer may include at least one of Ti, Ni, Al, Ag, Cr, Au, and Cu. By pattering the pad layer, the first pads <NUM> may be respectively formed on the first conductivity-type semiconductor layers <NUM>, and the second pads <NUM> may be respectively formed on the ohmic layers <NUM>.

Referring to <FIG> and <FIG>, by polishing a second surface <NUM> of the substrate <NUM> opposing the first surface <NUM> through a process, such as chemical mechanical polishing or others, the substrate <NUM> may be formed thin.

Referring to <FIG> and <FIG>, a first concave part <NUM> may be formed in the first surface <NUM> of the substrate <NUM>. For example, the first concave part <NUM> may be formed in the first surface <NUM> of the substrate <NUM> by a laser process or an etching process.

A first light shielding layer <NUM>, which fills at least a portion of the first concave part <NUM> may be formed on the first surface <NUM> of the substrate <NUM> by a process, such as plating, corrosion, deposition, taping, painting, and screen printing. The first light shielding layer <NUM> may include metal, such as Ti, Ni, Al, Ag, and Cr, or may include a material, such as a photoresist, epoxy, PDMS, and a black matrix.

According to an exemplary embodiment, through the processes of <FIG> and <FIG>, the light emitting device illustrated in <FIG> and <FIG> may be formed.

Referring to <FIG> and <FIG>, a second concave part <NUM> may be formed in the second surface <NUM> of the substrate <NUM>. For example, the second concave part <NUM> may be formed in the second surface <NUM> of the substrate <NUM> by a laser process or an etching process.

A second light shielding layer <NUM>, which fills at least a portion of the second concave part <NUM> and includes openings exposing light emitting areas EA of the substrate <NUM>, may be formed on the second surface <NUM> of the substrate <NUM> by a process, such as plating, corrosion, deposition, taping, painting, and screen printing. The second light shielding layer <NUM> may include metal, such as Ti, Ni, Al, Ag, and Cr, or may include a material, such as a photoresist, epoxy, PDMS, and a black matrix.

While the second concave part <NUM> and the second light shielding layer <NUM> are described as being formed after forming the first concave part <NUM> and the first light shielding layer <NUM>, however, in some exemplary embodiments, the first light shielding layer <NUM> and the second light shielding layer <NUM> may be formed after forming the first concave part <NUM> and the second concave part <NUM>.

In this process, when the second light shielding layer <NUM> is formed to be retained only in the second concave part <NUM> through the processes of <FIG> and <FIG>, the light emitting device illustrated in <FIG> and <FIG> may be formed.

In some exemplary embodiments, referring back to <FIG> and <FIG>, rough structures PT may be formed on the second surface <NUM> of the substrate <NUM> corresponding to the light emitting areas EA. For example, the rough structures PT may be formed on the second surface <NUM> of the substrate <NUM> by using a process, such as sandblasting, etching, and grinding.

Hereafter, a method for manufacturing a light emitting device according to another exemplary embodiment will be described. In particular, a method for manufacturing the light emitting device illustrated in <FIG> will be described as an example.

<FIG> are schematic top views illustrating a method for manufacturing a light emitting device according to another exemplary embodiment, and <FIG> are cross-sectional views taken along the lines A-A' of <FIG>.

Referring to <FIG> and <FIG>, circuit patterns including first pads <NUM> may be formed on a first surface <NUM> of a substrate <NUM>.

The substrate <NUM> may include a plurality of cell areas CA and a peripheral area PA excluding the cell areas CA. The cell areas CA may include light emitting areas EA, each of which is smaller than each cell area CA.

The first pads <NUM> may be disposed while exposing the light emitting areas EA. For example, when the substrate <NUM> has substantially a quadrangular structure, the first pads <NUM> may be disposed at the respective corners of the substrate <NUM>. In order to expose the light emitting areas EA, each of the first pads <NUM> may have substantially an L-shaped structure in a plan view.

Referring to <FIG> and <FIG>, after forming a first conductivity-type semiconductor layer <NUM>, an active layer <NUM>, a second conductivity-type semiconductor layer <NUM>, and an ohmic layer <NUM> on the first surface <NUM> of the substrate <NUM> on which the circuit patterns including the first pads <NUM> are formed, a plurality of light emitting cells LEC_1 and LEC_2 may be formed in the respective cell areas CA by etching, as shown in <FIG> and <FIG>.

According to an exemplary embodiment, first conductivity-type semiconductor layer <NUM> of the respective light emitting cells LEC_1 and LEC_2 may be disposed while being brought into electrical contact with the first pads <NUM>. Each of the first pads <NUM> may include at least one of Ti, Ni, Al, Ag, Cr, Au, and Cu.

According to an exemplary embodiment, the respective first pads <NUM> may function as a light shielding layer by selectively exposing the light emitting areas EA and covering the other portion.

Referring to <FIG> and <FIG>, a passivation layer PVT may be conformally formed on the light emitting cells LEC_1 and LEC_2, and, by etching the passivation layer PVT, openings exposing portions of ohmic layers <NUM> may be formed. A second pad <NUM>, which fills the openings and extends onto the first surface <NUM> of the substrate <NUM>, may be formed on the passivation layer PVT. The second pad <NUM> may be electrically coupled with the ohmic layers <NUM> in common.

According to an exemplary embodiment, the second pad <NUM> may be formed while covering the top surfaces of the respective ohmic layers <NUM>. In this manner, as the second pad <NUM> covers the top surfaces of the respective ohmic layers <NUM>, light generated from active layers <NUM> may be reflected toward the substrate <NUM>. While the second pad <NUM> may cover the light emitting areas EA on the ohmic layers <NUM>, the second pad <NUM> may expose the respective light emitting areas EA on the first surface <NUM> of the substrate <NUM>.

Referring back to <FIG>, a concave part <NUM> may be formed on a second surface <NUM> of the substrate <NUM> opposing the first surface <NUM>, by using a laser process or an etching process. A light shielding layer <NUM>, which fills at least a portion of the concave part <NUM> and exposes the respective light emitting areas EA, may be formed on the second surface <NUM> of the substrate <NUM>. The light shielding layer <NUM> may include metal, such as Ti, Ni, Al, Ag, and Cr, or may include a material, such as a photoresist, epoxy, PDMS, and a black matrix.

By the first pads <NUM> formed on the first surface <NUM> of the substrate <NUM> and the light shielding layer <NUM> formed on the second surface <NUM> of the substrate <NUM>, the light emitting areas EA may be defined.

Claim 1:
A light emitting device comprising:
a substrate (<NUM>) having first surface (<NUM>) and a second surface (<NUM>) opposing the first surface, the first surface having a concave part extending to the inside of the substrate;
a plurality of light emitting cells (LEC_1, LEC_2) disposed on the first surface of the substrate; and
a light shielding layer (<NUM>) filling at least a portion of the concave part and disposed between the plurality of light emitting cells;
wherein the light shielding layer is disposed on the first surface of the substrate; and
wherein light generated from the plurality of light emitting cells is emitted through the second surface of the substrate, and
wherein the concave part includes a vertical part (VL) extending along a first direction and
horizontal part (HL) along a second direction crossing the first direction in a top view,
characterised by
an insulating layer (<NUM>) disposed on the light shielding layer.