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EP-4006885-B1 - ROLLABLE DISPLAY DEVICE

EP4006885B1EP 4006885 B1EP4006885 B1EP 4006885B1EP-4006885-B1

Inventors

  • AHN, YOUNGJOON
  • KIM, JAEYONG
  • MINN, Changshik
  • JIN, KWANEUN

Dates

Publication Date
20260506
Application Date
20190729

Claims (15)

  1. A rollable display device comprising: a roller (143); a display part (20) on which the roller (143) rolls and which comprises a display panel (10) and a module cover (15) supporting the display panel (10), the module cover (15) comprising a bending portion (15a) at both end portions of the display part (20), which bends toward the roller (143) in a second direction intersecting a first direction in which the display part (20) rolls, characterized in that the module cover comprises a first side facing the roller (143) and a second side facing the display panel (10), in that the first side and the second side have different bending strengths, and in that a first height of the bending portion (15a) at which the display part (20) is unrolled from the roller (143) is different from a second height thereof at which the display part (20) is rolled up around the roller (143).
  2. The rollable display device of claim 1, wherein the second side is a side where the display panel (10) is joined to the module cover (15), and wherein, preferably, the bending strength of the second side is greater than the bending strength of the first side.
  3. The rollable display device of claim 1 or 2, wherein the ratio h1/h2 of the first height h1 and second height h2 of the bending portion (15a) is from 1 to 5.
  4. The rollable display device of any one of claims 1 to 3, wherein the module cover (15) comprises a first skin (151) and a second skin (153) facing the first skin (151) and having a buckling stress greater than that of the first skin, and the module cover (15) is joined to the display panel (10) so that the second skin (153) faces the display panel (10), and wherein, preferably, the difference in buckling stress between the first skin (151) and the second skin (153) is 10 or greater.
  5. The rollable display device of claim 4, wherein the first skin (151) contains less polymer matrix composites than the second skin (153) or contains no polymer matrix composites.
  6. The rollable display device of claim 4 or 5, wherein at least one of the first skin (151) and the second skin (153) contains reinforced fiber, wherein, preferably, a first reinforced fiber included in the first skin (151) is woven in a different way from a second reinforced fiber included in the second skin (153).
  7. The rollable display device of claim 6, wherein the second reinforced fiber comprises first sub skins (153a) with original yarns arranged only in a first direction and second sub skins (153b) with original yarns woven in a second direction orthogonal to the first direction, wherein the first direction is the same as the direction in which the display part (20) rolls, and the number of first sub skins (153a) is larger than the number of second sub skins (153b).
  8. The rollable display device of any one of claims 4 to 7, wherein the thickness of the second skin (153) is equal to or larger than that of the first skin (151) and is equal to or smaller than 1 mm.
  9. The rollable display device of claim 6, wherein the first reinforced fiber only comprises a plurality of sub skins (153a, 153b) woven in the first direction.
  10. The rollable display device of any one of claims 5 to 9, further comprising: a core (155) sandwiched between the first skin (151) and the second skin (153), wherein, preferably, the core (155) has a honeycomb structure comprising hexagonal columns (155a), and the width B1 of the hexagonal columns (155a) in the first direction is smaller than the width B2 thereof in the rolling direction.
  11. The rollable display device of claim 10, wherein the ratio B2/B1 of the width B2 in the second direction and the width B1 in the first direction is from 1.5 to 7, and wherein, preferably, the ratio B1/G1 of the thickness G1 of the hexagonal columns (155a) and the width B1 in the first direction is from 3 to 20.
  12. The rollable display device of claim 10 or 11, wherein the thickness of at least one of the first and second skins (151, 153) is equal to or smaller than the bending strength of the core (155).
  13. The rollable display device of any one of claims 10 to 12, wherein the second skin (153) is joined to the core (155) by an adhesive layer, and the shore hardness of the adhesive layer is 80 or smaller.
  14. The rollable display device of any one of claims 4 to 13, wherein the bending portion (15a) is selectively formed only on an end portion of the second skin (153).
  15. The rollable display device of any one of claims 10 to 14, wherein the height of the bending portion (15a) is greater than the sum of the thickness of the first skin (151) and the thickness of the core (155).

Description

Technical Field The present disclosure relates to a rollable display device on which a display rolls. Background Art Along with the development of information society, the demand for display devices is increasing in various forms. To meet this demand, various types of display devices such as liquid crystal displays (LCDs), plasma display panels (PDPs), electroluminescent displays (ELDs), and vacuum fluorescent displays (VFDs), have been studied and used in recent years. Among them, display devices using organic light emitting diodes (OLEDs) are advantageous in that they can be implemented as ultrathin and flexible displays since they have luminance characteristics and viewing angle characteristics, compared to liquid display devices, and require backlight units. Moreover, flexible displays are applied and used in various fields. For example, they may be implemented as rollable display devices that can be unrolled when the display is in use and that can be rolled up and kept in storage when the display is not in use. US2017/344073 A1 discloses a rollable display comprising a flexible display panel, using bistable reeled composite units . US2016/054758 A1 discloses a flexible display device having a bending adjuster. Disclosure Technical Problem The present disclosure has been made in an effort to solve the aforementioned problems and other problems. An aspect of the present disclosure is to provide a module cover that can be used in a rollable display and a rollable display device including the same. Technical Solution A rollable display device according to an embodiment of the present disclosure may include: a roller; a display part on which the roller rolls and which includes a display panel and a module cover supporting the display panel, the module cover including a bending portion at both end portions of the display part, which bends toward the roller in a second direction intersecting a first direction in which the display part rolls, with a first side facing the roller and a second side facing the display panel having different bending strengths, wherein a first height of the bending portion at which the display part is unrolled from the roller is different from a second height thereof at which the display part is rolled up around the roller. The second side may be a side where the display panel is joined to the module cover, and the bending strength of the second side may be greater than the bending strength of the first side. The ratio h1/h2 of the first height h1 and second height h2 of the bending portion may be from 1 to 5. The module cover may include a first skin and a second skin facing the first skin and having a buckling stress greater than that of the first skin, and the module cover may be joined to the display panel so that the second skin faces the display panel. The first skin may contain less polymer matrix composites than the second skin or contain no polymer matrix composites. The difference in buckling stress between the first skin and the second skin may be 10 or greater. At least one of the first skin and the second skin may contain reinforced fiber, and a first reinforced fiber included in the first skin may be woven in a different way from a second reinforced fiber included in the second skin. The second reinforced fiber may include first sub skins with original yarns arranged only in a first direction and second sub skins with original yarns woven in a second direction orthogonal to the first direction, wherein the first direction may be the same as the direction in which the display part rolls, and the number of first sub skins may be larger than the number of second sub skins. The thickness of the second skin may be equal to or larger than that of the first skin and may be equal to or smaller than 1 mm. The first reinforced fiber may only include a plurality of sub skins woven in the first direction. The rollable display device may further include a core sandwiched between the first skin and the second skin. The core may have a honeycomb structure including hexagonal columns, wherein the width of the hexagonal columns in the first direction may be smaller than the width thereof in the rolling direction. The ratio B2/B1 of the width B2 in the second direction and the width B1 in the first direction may be from 1.5 to 7. The ratio B1/G1 of the thickness G1 of the hexagonal columns and the width B1 in the first direction may be from 3 to 20. The thickness of at least one of the first and second skins may be equal to or smaller than the bending strength of the core. The second skin may be joined to the core by an adhesive layer, and the shore hardness of the adhesive layer may be 80 or smaller. The bending portion may be selectively formed only on an end portion of the second skin. The height of the bending portion may be greater than the sum of the thickness of the first skin and the thickness of the core. The rollable display device may further include: a link assembly includin