P‐109: Stress‐Free Folding Hinge for Foldable OLED Display Device

Han, Ho Jung; Cho, Won Jin; Lee, Seoung Jun; Park, Hyun Min; Hwang, In-Sun

doi:10.1002/sdtp.14950

Cited by 6 publications

(5 citation statements)

References 1 publication

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“…Moreover in 2020, Zhang et al 27 designed a 17.3-inch WQHD foldable AMOLED display. Additionally, in 2021, Han et al 28 demonstrated a SFF (stress-free folding) hinge with VAS (virtual axis structure) and MAS (modulized assembly structure). The proposed hinge provided stress-free folding motion and 200k folding reliability having less than 20% torque reduction.…”

Section: Classification Of Oledmentioning

confidence: 99%

Review—Advancements and Perspectives of Organic LED: In Depth Analysis of Architectural Design, Characteristics Parameters, Fabrication Techniques, and Applications

Yadav

Mittal

Negi

2023

ECS J. Solid State Sci. Technol.

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This article presents a review on various aspect of organic light emitting diodes (OLEDs), such as their working, various categorization, impact of fabrication methodologies (organic vapor phase deposition, vacuum thermal evaporation, inkjet printing etc.) that are low-cost and their applications in serval domains like medical, sensor, display, lighting etc. Three categorizations of OLED are discussed with respect to circuit, architecture and color of emission. Different layers of multi-layered structures such as injection layer, transport layer, block layers are also reviewed and their impacts are analyzed and compared. Moreover, an experimental fabrication technique for flexible substrate is reviewed that highlights low-cost fabrication method. In this technique, dynamic viscosity and contact angle are measured using rotational viscometer and contact angle meter, respectively. The result illustrates sheet resistance and effective opening ratio of 3.8 ohms per square and 82.5%, correspondingly. Additionally, various performance parameters like luminescence, external quantum efficiency, and current efficiency are compared. The paper also incorporates recent advancement in organic thin film transistors along with some OTFT driven OLED devices.

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Section: Classification Of Oledmentioning

confidence: 99%

Review—Advancements and Perspectives of Organic LED: In Depth Analysis of Architectural Design, Characteristics Parameters, Fabrication Techniques, and Applications

Yadav

Mittal

Negi

2023

ECS J. Solid State Sci. Technol.

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“…The centers of these half circle slides are located above top of plates which an OLED panel is attached on, inside of OLED panel when it attached on the plates in order to minimize the stress by folding motion. [5] In general, its torque value is controlled by the spring force and CAM shape on one side of the spring as shown in figure 2. When hinge folds, rotating part and stationary part are rubbed each other and spring force add friction force on it.…”

Section: Sff Hinge With Vasmentioning

confidence: 99%

“…At the SID 2021 last year, we have presented our stress-free folding (SFF) hinge technology with the virtual axis structure (VAS). [5] We would enlarge this technology to large size foldable device and then it can have the same folding radius as foldable mobile phone, ~ 1.5mm. In order to apply this SFF hinge up to 17" size, it has to have very high torque value to have freestop function.…”

Section: Introductionmentioning

confidence: 99%

P‐138: High Torque Hinge for Large Size Foldable Device

Lee¹,

Park²,

Hwang³

2022

Symp Digest of Tech Papers

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In order to expand the mobile foldable technology to large size IT device, we have developed a folding hinge having high torque value. It has stress‐free folding characteristics by virtual axis structure and compact dimension by the parallel arrangement of a folding part and a torque part. Therefore, we can make a large size foldable device which is slim and narrow bezel. It has the torque value of 14 kgf·cm on device and free‐stop function. By the enlargement of friction area by the change of CAM concept and the structural optimization we can reduce abrasion of hinge CAM surface, and the torque reduction by 70k folding lifetime test is less than 20% of its initial value. It is very important progress in the foldable technology.

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“…The flexible electronic device industry has experienced tremendous growth since the introduction of foldable smartphones in late 2018 [1,2]. Despite their popularity, the market for flexible devices is still in its early stages and limited to high-end products due largely to the complex design and manufacturing challenges.…”

Section: Introductionmentioning

confidence: 99%

Using an Interlayer to Toughen Flexible Colorless Polyimide-Based Cover Windows

Matsuda,

Cen,

et al. 2023

Coatings

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Colorless polyimide (PI)-based flexible cover windows are a critical component of flexible electronics to protect devices from unwanted chemical and mechanical damage. The integration of flexible colorless PI-based windows into electronics applications is limited by the embrittlement of some colorless PI films when they are coated with hard coats. Here, we investigate the embrittlement mechanism of hard-coated colorless PI films and the role of interlayers in toughening the colorless PI-based cover windows for flexible electronics applications. A fracture mechanics approach combined with finite element analysis (FEA) models is employed to compute fracture strain, εc, for different crack cases in the bilayer (hard coated colorless PI) and trilayer (with an additional interlayer) cover windows. For the model inputs and validation, the material properties of the cover windows are characterized. We show that the embrittlement is attributed to the fracture behavior of the cover windows, and placing a ductile interlayer increases the εc of colorless PI films. Using the fracture analysis as a design guide, we fabricate a trilayer cover window with an acrylic thermoset interlayer and demonstrate an improvement of the εc of the colorless PI cover window by ~42%. We believe our analysis provides insights into design guides for mechanically robust cover windows using colorless PI films and flexible HCs for emerging flexible electronics.

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P‐109: Stress‐Free Folding Hinge for Foldable OLED Display Device

Cited by 6 publications

References 1 publication

Review—Advancements and Perspectives of Organic LED: In Depth Analysis of Architectural Design, Characteristics Parameters, Fabrication Techniques, and Applications

Review—Advancements and Perspectives of Organic LED: In Depth Analysis of Architectural Design, Characteristics Parameters, Fabrication Techniques, and Applications

P‐138: High Torque Hinge for Large Size Foldable Device

Using an Interlayer to Toughen Flexible Colorless Polyimide-Based Cover Windows

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