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EP-4456135-B1 - DISPLAY DEVICE

EP4456135B1EP 4456135 B1EP4456135 B1EP 4456135B1EP-4456135-B1

Inventors

  • KIM, SU JEONG
  • MIN, DAE HONG

Dates

Publication Date
20260506
Application Date
20240321

Claims (11)

  1. A light-emitting element structure comprising: light-emitting elements (LE) comprising a first light-emitting element (LE1) for emitting light of a first wavelength and a second light-emitting element (LE2) for emitting light of a second wavelength, and comprising current-spreading layers (CSL) comprising a first current-spreading layer (CSL1) having a first width (W1C) on the first light-emitting element (LE1) and a second current-spreading layer (CSL2) having a second width (W2C) that is less than the first width (W1C) on the second light-emitting element (LE2); and an insulating layer (INS1) between the light-emitting elements (LE), characterized in that the first light-emitting element (LE1) and the second light-emitting element (LE2) have the same width (W1, W2).
  2. The light-emitting element structure of claim 1, wherein the first wavelength corresponds to red light, and wherein the second wavelength corresponds to green light or blue light.
  3. The light-emitting element structure of any one of the preceding claims, wherein the light-emitting elements (LE) further comprise a third light-emitting element (LE3) for emitting light of a third wavelength, wherein the current-spreading layers (CSL) further comprise a third current-spreading layer (CSL3) on the third light-emitting element (LE3), wherein the first wavelength corresponds to red light, wherein the second wavelength corresponds to green light, and wherein the third wavelength corresponds to blue light.
  4. The light-emitting element structure of claim 3, further comprising a first light-emitting area (EA1) corresponding to the first current-spreading layer (CSL1), a second light-emitting area (EA2) corresponding to the second current-spreading layer (CSL2), and a third light-emitting area (EA3) corresponding to the third current-spreading layer (CSL3), wherein a first emission region of the first light-emitting area (EA1) is larger than a second emission region of the second light-emitting area (EA2) and a third emission region of the third light-emitting area (EA3).
  5. The light-emitting element structure of claim 4, wherein the second emission region is larger than or equal in size to the third emission region.
  6. The light-emitting element structure of claim 3, 4 or 5, wherein the planar shape of the first current-spreading layer (CSL1), the second current-spreading layer (CSL2), and the third current-spreading layer (CSL3) is circular or polygonal.
  7. The light-emitting element structure of any one of claims 3 to 6, wherein the light-emitting elements (LE) comprise a first semiconductor layer (SEM1), a second semiconductor layer (SEM2), and an active layer (MQW) between the first semiconductor layer (SEM1) and the second semiconductor layer (SEM2), wherein the first light-emitting element (LE1) comprises a first active layer (MQW1), wherein the second light-emitting element (LE2) comprises a second active layer (MQW2), wherein the third light-emitting element (LE3) comprises a third active layer (MQW3), wherein the first active layer, the second active layer, and the third active layer contain indium, wherein an indium content of the first active layer is greater than an indium content of the second active layer and an indium content of the third active layer, and wherein the indium content of the second active layer is greater than the indium content of the third active layer.
  8. The light-emitting element structure of any one of the preceding claims, further comprising connection electrodes (126) on the current-spreading layers (CSL), and wherein the connection electrodes respectively have the same width (W1C, W2C, W3C) as the current-spreading layers (CSL).
  9. The light-emitting element structure of any one of claims 1 to 7, further comprising connection electrodes (126) on the current-spreading layers (CSL), and respectively having widths that are different from the widths (W1C, W2C, W3C) of the current-spreading layers (CSL).
  10. A display device comprising: pixel electrodes (111) on a substrate (110); a light-emitting element structure according to any one of the preceding claims on the pixel electrodes (111).
  11. The display device of claim 10 when dependent on claim 8 or 9, wherein the connection electrodes (126) are between the current-spreading layers (CSL) and the pixel electrodes (111).

Description

BACKGROUND 1. Field The present invention relates to a light-emitting element structure and a display device. 2. Description of the Related Art As the information society develops, the demand for a display device for displaying an image is increasing in various forms. The display device may be a flat panel display, such as a liquid crystal display, a field emission display, or a light-emitting display panel. The light-emitting display device may include an organic light-emitting diode device including an organic light-emitting diode element as a light-emitting element, an inorganic light-emitting device including an inorganic semiconductor element as a light-emitting element, or an ultra-small light-emitting diode element (or a micro light-emitting diode element) as a light-emitting element. Recently, a head mounted display including a light-emitting display device has been developed. The head mounted display (HMD) is a spectacle-type monitor device of virtual reality (VR) or augmented reality (AR) that the user wears in the form of glasses or a helmet, the focus of which being formed at a close distance in front of the user's eyes. A high-resolution subminiature light-emitting diode display panel including the micro light-emitting diode element may be applied to the head mounted display. US 2023/0048385 A1 and US 2023/0046443 A1 each disclose a display device and a method for fabrication thereof. SUMMARY The present invention provides a light-emitting element structure and a display device capable of improving the luminous efficiency of light-emitting elements for emitting red light by adjusting the width of a current-spreading layer according to the luminous efficiency of the light-emitting element. However, the present invention is not restricted to the one set forth herein. The above and other aspects of the present invention will become more apparent to one of ordinary skill in the art to which the present disclosure pertains by referencing the detailed description of the present invention given below. According to an aspect of the invention, there is provided a light-emitting structure as set out in claim 1. According to embodiments, a light-emitting element structure includes a growth substrate, light-emitting elements including a first light-emitting element for emitting light of a first wavelength and a second light-emitting element for emitting light of a second wavelength on the growth substrate, and including current-spreading layers including a first current-spreading layer having a first width on the first light-emitting element and a second current-spreading layer having a second width that is less than the first width on the second light-emitting element, and an insulating layer between the light-emitting elements. The first light-emitting element and the second light-emitting element have the same width. The first wavelength may correspond to red light, wherein the second wavelength corresponds to green light or blue light. The light-emitting elements may further include a third light-emitting element for emitting light of a third wavelength, wherein the current-spreading layers further include a third current-spreading layer on the third light-emitting element, wherein the first wavelength corresponds to red light, wherein the second wavelength corresponds to green light, and wherein the third wavelength corresponds to blue light. The light-emitting element structure may further include a first light-emitting area corresponding to the first current-spreading layer, a second light-emitting area corresponding to the second current-spreading layer, and a third light-emitting area corresponding to the third current-spreading layer, wherein a first emission region of the first light-emitting area is greater than a second emission region of the second light-emitting area and a third emission region of the third light-emitting element. The second emission region may be greater than or equal to the third emission region. A planar shape of the first current-spreading layer, the second current-spreading layer, and the third current-spreading layer may be circular or polygonal. The light-emitting elements may include a first semiconductor layer, a second semiconductor layer, and an active layer between the first semiconductor layer and the second semiconductor layer, wherein the first light-emitting element includes a first active layer, wherein the second light-emitting element includes a second active layer, wherein the third light-emitting element includes a third active layer, wherein the first active layer, the second active layer, and the third active layer contain indium, wherein an indium content of the first active layer is greater than an indium content of the second active layer and an indium content of the third active layer, and wherein the indium content of the second active layer is greater than the indium content of the third active layer. The light-emitting element structure may furt