Patent Description:
Flexible displays may allow for the creation of innovating form factors, bringing new usages for end users. Current foldable hinge designs may enable the folding and unfolding of these flexible displays. There are many design challenges with integrating foldable displays into devices, including the panel mounting and hinge design for reliable panel operation over the device life. Integrating the panel with the hinge design is one example challenge. A typical hinge design with a fixed pivoting axis does not allow the arc length of the foldable display to be maintained while closing and opening, which may damage the display or cause other issues for the display.

<CIT> describes an electronic device including two housing structures, a hinge structure, and a flexible display. The hinge structure includes four sawtoothed spur gears and guide structures fixed to the housing structures and rotated by the gears.

<CIT> describes an electronic device including a flexible display that overlaps an axis. The display is supported by a housing with first and second portions that rotate relative to each other about the axis.

The present invention is defined in the independent claim. The dependent claims recite selected optional features.

In the following description, numerous specific details are set forth, such as examples of specific configurations, structures, architectural details, etc. in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that these specific details need not all be employed to practice embodiments of the present invention. In some instances, well known components or methods may be utilized, and such details haven't been described in detail in order to avoid unnecessarily obscuring embodiments of the present invention.

Flexible displays may allow for the creation of innovating form factors, bringing new usages for end users. Existing foldable hinge designs may enable the folding and unfolding of these flexible displays. There are many design challenges with integrating foldable displays into devices, including the panel mounting and hinge design for reliable panel operation over the device life. Integrating the panel with the hinge design is one example challenge. A typical hinge design with a fixed pivoting axis does not allow the arc length of the foldable display to be maintained while closing and opening, which may damage the display or cause other issues for the display.

Existing hinge designs may exhibit one or more of the following disadvantages: a lot of moving parts and precise components that can end up jamming or wearing out of the mechanism, thus causing damage to the flexible display; "backlash" between the gears may be present; the weight of the foldable display mechanism can be quite high (e.g., ~<NUM>% of the product weight itself); or may have small gaps or opening through which foreign material/particles/debris can enter and damage the mechanism.

Accordingly, embodiments disclosed herein may include a robust hinge design for a foldable computing system that provides one or more advantages over existing hinge designs. For example, in some cases, a hinge design as described herein may eliminate or reduce the unwanted stress on the flexible display (e.g., flexible organic light emitting diode (FOLED)-based display) during opening, closing, and usage of the computing system. As another example, in some cases, a hinge design as described herein may prevent the entry of foreign particles or debris into parts of the computing system. As yet another example, in some cases, a hinge design as described herein may provide support to the flexible display (e.g., for systems with a higher bend radius). As yet another example, in some cases, a hinge mechanism as described herein may provide modularity and easy serviceability (e.g., when replacing the hinge) without the need for the flexible display to be accessed or removed, which is lacking in current designs.

In embodiments, a synchronous, low backlash, multigear driven hinge mechanism is utilized. The hinge mechanism may include a unique opening trajectory that respects the folding & unfolding curve for a given bend radius of the flexible display. In some cases, a protection layer of low energy material may be incorporated at or near the bend area of the flexible display to prevent fatigue or other issues. In some embodiments, ingress protection may be included for prevention of debris and foreign particles into the hinge mechanism or other internal components. In some embodiments, e.g., foldable computing systems with higher bend radii, a support mechanism may be included that can support the display all the way from a lay-flat mode (180º) to a "laptop mode" (~ 90º) (e.g., for workflows that require touching at or near the bend of the screen). Further, in some embodiments, the bend radius of the foldable device may be as small as <NUM>.

<FIG> illustrate views of an example foldable computing device <NUM> that may incorporate a flexible display. The example foldable computing device <NUM> includes two device housings <NUM> and two flat display support panels <NUM> that are coupled together via the spine <NUM>. In certain embodiments, computer device components (e.g., those shown in <FIG>) mayb e housed within one or both of the device housings <NUM>, and a foldable display (e.g., FOLED) may be coupled to the flat display support panels <NUM>. The spine <NUM> includes multiple hinge mechanisms <NUM> to allow the device <NUM> to fold. In the example shown, the device <NUM> includes a hinge mechanism 108b that includes a gear assembly (e.g., a crossed-helical gear assembly), and two other hinge mechanisms 108a, 108c that do not include gear assemblies. The hinge mechanism 108b may be similar to the example mechanism <NUM> of <FIG> and described further below, while the hinge mechanism 108a, 108c may be similar to the example mechanism <NUM> but without the gear assembly (i.e., the curved rack apparatuses in each of the mechanisms <NUM> may be shaped in the same way). Although a particular number and arrangement of hinge mechanisms are shown in <FIG>, embodiments of may include any suitable number of hinge mechanisms in any suitable arrangement, and any number of the included hinge mechanisms may include a gear assembly.

<FIG> illustrate example views of a hinge mechanism <NUM> that may be incorporated into a foldable computing device with a flexible display. In particular, <FIG> illustrates the example hinge mechanism <NUM> in solid form, while <FIG> illustrates the example hinge mechanism <NUM> in wireline form.

The example hinge mechanism <NUM> includes a central housing <NUM>. The housing <NUM> defines a cavity <NUM> in which a low backlash synchronous gear assembly <NUM> may be housed. The housing <NUM> further defines cavities <NUM> in which curved rack apparatuses <NUM> may be housed. The curved rack apparatuses may be designed to couple to respective support plates for a flexible display (e.g., support panels <NUM>). The curved rack apparatuses <NUM> include a uniquely curved arcuate surface <NUM> that forces rotation in a way that always ensures that an overall arc length of the flexible display is maintained throughout the range of motion (e.g., going from lay-flat to a folded state). The gear assembly <NUM> is designed that the curved rack apparatuses <NUM> may rotate synchronously with a varying pivot or position for every small step angle. To achieve the synchronous movement, the gear assembly <NUM> utilizes a set of crossed helical gears, which may allow for smooth and noise free operation.

The example curved rack apparatuses <NUM> each define an arcuate surface <NUM> having a non-uniform radius of curvature. The surface <NUM> connects to the surface <NUM>, which includes at least one substantially flat portion (e.g., for flush mating with a support panel such as panel <NUM>). The curvature of the arcuate surface <NUM> is defined such that an overall arc length of a flexible display remains the same throughout the folding range of a device. One way of determining the curvature of the arcuate surface <NUM> is described further below with respect to <FIG>. Each curved rack apparatus <NUM> further defines an arcuate set of gear teeth <NUM> that may interact with the gears <NUM> of the gear assembly <NUM>. The arcuate set of gear teeth <NUM> are concentric with the arcuate surface <NUM> and have a non-uniform radius of curvature, which may be similar to the curvature of the arcuate surface <NUM>. That is, the origin of the curvature for both the set of gear teeth <NUM> and the arcuate surface <NUM> is the same.

Each curved rack apparatus <NUM> further defines a portion <NUM> for coupling the curved rack apparatus <NUM> to a display support panel (e.g., screw holes or other type of attachment mechanism to couple the apparatus <NUM> to a support panel such as panel <NUM>). The curved rack apparatus <NUM> and display support panel may be coupled together in any suitable manner, such as, for example, using adhesives, screws, or other attachment means. The curved rack apparatuses <NUM> may be disposed in their respective housing cavities <NUM> such that the surfaces <NUM> are in contact with an inner surface of the housing cavities <NUM>.

The example gear assembly <NUM> includes two spur gears <NUM> that couple to the arcuate set of gear teeth <NUM> of the curved rack apparatuses <NUM>. The spur gears <NUM> are coupled to helical gears <NUM>. The spur gears <NUM> and helical gears <NUM> are in-line with one another (i.e., the rotational axis of 222a and 224a are the same, and rotational axis of 222b and 224b are the same), while the helical gears 224a, 224b have rotational axes that are offset from one another. The helical gears 224a, 224b are coupled to one another via another helical gear <NUM>, which has a lower helix angle than the helical gears <NUM>. The example gear assembly <NUM> may allow for synchronous, low backlash operation.

<FIG> illustrates a principle of operation for the example hinge mechanism <NUM> of <FIG>. In particular, <FIG> illustrates a way that the arc length of a flexible display <NUM> changes as the display is moved between the flat and folded states. In addition, <FIG> illustrates how the origin <NUM> of the arc moves as the display is moved between the flat and folded states. The trajectory of the origin as it moves between 302a and 302n may dictate the shape of the curved rack apparatus <NUM> (e.g., the curvature of the surface <NUM>) of the hinge mechanism <NUM>. It will be noted that the trajectory of the origin forms a curvature that has a non-uniform radius. By forming the curved rack apparatus <NUM> according to this trajectory, the hinge mechanism <NUM> may maintain a constant arc length for the flexible display throughout the range of motion between the folded and flat states.

<FIG> illustrates a side view of an example foldable device <NUM> that incorporates the hinge mechanism <NUM> of <FIG>. The example device <NUM> includes two flat display support panels <NUM> coupled to the hinge mechanism <NUM> (e.g., via the curved rack apparatuses <NUM>), and two device housings <NUM> that are each respectively coupled to one of the display support panels <NUM>. The device <NUM> further includes a flexible display <NUM> coupled to the display support panels <NUM> (on a surface opposite the surface to which the mechanism <NUM> is coupled).

In certain embodiments, to ensure that the flexible display <NUM> is well protected, a release liner material <NUM> with low surface energy may be positioned between the support plate <NUM> and the display <NUM> (e.g., on an end of the support plate <NUM> that is near the folding axis, as shown in <FIG>). The liner material <NUM> may allow adhesion-free separation between the support plate <NUM> and the flexible display <NUM> at and near the bend area as shown in <FIG>. In some embodiments, the liner material <NUM> may be a low surface energy material, such as PET. A low surface energy material may refer to a material having a surface energy less than <NUM> dynes/cm (e.g., between approximately <NUM>-<NUM> dynes/cm).

<FIG> illustrate side views of another example foldable device <NUM> that incorporates the hinge mechanism <NUM> of <FIG>. In the examples shown, the device <NUM> includes ingress protection features <NUM> to ensure that foreign particles and debris do not enter into the device, preventing potential jamming of the hinge mechanism <NUM> and potential damage to a flexible display of the device. The ingress protection features <NUM> may include a diaphragm material, such as, for example Teflon-coated rubber. The ingress protection features <NUM> may be disposed between the hinge mechanism <NUM> and the device housing <NUM> of the device <NUM> as shown. The ingress protection features <NUM> may accordingly prevent ingress of foreign particles into the hinge mechanism <NUM> or the device housing <NUM>.

<FIG> illustrates a side view of another example foldable device <NUM> that incorporates the hinge mechanism <NUM> of <FIG>. In the example shown, the device <NUM> includes a display support system, which may be beneficial for devices having a larger bend radius. The display support system may support the flexible display <NUM> of the device while the device is in a bent state (e.g., when interaction is necessary with the display <NUM> in a laptop mode) and includes, for each wing of the device <NUM>, a pulley <NUM>, support plate <NUM> (e.g., sheet metal (e.g., <NUM> Titanium sheet) or another suitable material), and connector <NUM> (e.g., string or another suitable connection mechanism) that couples the support plate <NUM> to the curved rack apparatus <NUM>. In this example configuration, the amount of rotation of the curved rack apparatus <NUM> is directly linked to the angle of opening of the wings of the device <NUM>. When the wings are opened, for instance, the curved rack apparatus <NUM> may drive its shaft gears, and the connector <NUM> attached to these shaft gears may pull the support plate <NUM> in/out (based on the direction of rotation). The support plate <NUM> may provide the flexible display <NUM> with necessary backing support in the area of curvature whenever the wings of the device are in an orientation less than <NUM> degrees, which may allow for touch or other types of interaction with the display <NUM> in such orientation without causing damage to the display <NUM>.

<FIG> are block diagrams of example computer architectures that may be used in accordance with embodiments disclosed herein. For example, in some embodiments, a computing device containing one or more aspects shown in <FIG> (e.g., the processor core <NUM> of <FIG> or one or both of processors <NUM>, <NUM> of <FIG>) may utilize a foldable device and a hinge mechanism as described herein. In some embodiments, the computer architecture may be implemented within a mobile computing system, such as a laptop or notebook computer, tablet device, or mobile phone / smartphone. Other computer architecture designs known in the art for processors and computing systems may also be used. Generally, suitable computer architectures for embodiments disclosed herein can include, but are not limited to, configurations illustrated in <FIG>.

<FIG> is an example illustration of a processor according to an embodiment. Processor <NUM> is an example of a type of hardware device that can be used in connection with the implementations above. Processor <NUM> may be any type of processor, such as a microprocessor, an embedded processor, a digital signal processor (DSP), a network processor, a multi-core processor, a single core processor, or other device to execute code. Although only one processor <NUM> is illustrated in <FIG>, a processing element may alternatively include more than one of processor <NUM> illustrated in <FIG>. Processor <NUM> may be a single-threaded core or, for at least one embodiment, the processor <NUM> may be multi-threaded in that it may include more than one hardware thread context (or "logical processor") per core.

<FIG> also illustrates a memory <NUM> coupled to processor <NUM> in accordance with an embodiment. Memory <NUM> may be any of a wide variety of memories (including various layers of memory hierarchy) as are known or otherwise available to those of skill in the art. Such memory elements can include, but are not limited to, random access memory (RAM), read only memory (ROM), logic blocks of a field programmable gate array (FPGA), erasable programmable read only memory (EPROM), and electrically erasable programmable ROM (EEPROM).

Processor <NUM> can execute any type of instructions associated with algorithms, processes, or operations detailed herein. Generally, processor <NUM> can transform an element or an article (e.g., data) from one state or thing to another state or thing.

Code <NUM>, which may be one or more instructions to be executed by processor <NUM>, may be stored in memory <NUM>, or may be stored in software, hardware, firmware, or any suitable combination thereof, or in any other internal or external component, device, element, or object where appropriate and based on particular needs. In one example, processor <NUM> can follow a program sequence of instructions indicated by code <NUM>. Each instruction enters a front-end logic <NUM> and is processed by one or more decoders <NUM>. The decoder may generate, as its output, a micro operation such as a fixed width micro operation in a predefined format, or may generate other instructions, microinstructions, or control signals that reflect the original code instruction. Front-end logic <NUM> also includes register renaming logic <NUM> and scheduling logic <NUM>, which generally allocate resources and queue the operation corresponding to the instruction for execution.

Processor <NUM> can also include execution logic <NUM> having a set of execution units 716a, 716b, 716n, etc. Some embodiments may include a number of execution units dedicated to specific functions or sets of functions. Other embodiments may include only one execution unit or one execution unit that can perform a particular function. Execution logic <NUM> performs the operations specified by code instructions.

After completion of execution of the operations specified by the code instructions, back-end logic <NUM> can retire the instructions of code <NUM>. In one embodiment, processor <NUM> allows out of order execution but requires in order retirement of instructions. Retirement logic <NUM> may take a variety of known forms (e.g., re-order buffers or the like). In this manner, processor <NUM> is transformed during execution of code <NUM>, at least in terms of the output generated by the decoder, hardware registers and tables utilized by register renaming logic <NUM>, and any registers (not shown) modified by execution logic <NUM>.

Although not shown in <FIG>, a processing element may include other elements on a chip with processor <NUM>. For example, a processing element may include memory control logic along with processor <NUM>. The processing element may include I/O control logic and/or may include I/O control logic integrated with memory control logic. The processing element may also include one or more caches. In some embodiments, non-volatile memory (such as flash memory or fuses) may also be included on the chip with processor <NUM>.

<FIG> illustrates a computing system <NUM> that is arranged in a point-to-point (PtP) configuration according to an embodiment. In particular, <FIG> shows a system where processors, memory, and input/output devices are interconnected by a number of point-to-point interfaces. Generally, one or more of the computing systems described herein may be configured in the same or similar manner as computing system <NUM>.

Processors <NUM> and <NUM> may also each include integrated memory controller logic (MC) <NUM> and <NUM> to communicate with memory elements <NUM> and <NUM>. In alternative embodiments, memory controller logic <NUM> and <NUM> may be discrete logic separate from processors <NUM> and <NUM>. Memory elements <NUM> and/or <NUM> may store various data to be used by processors <NUM> and <NUM> in achieving operations and functionality outlined herein.

Processors <NUM> and <NUM> may be any type of processor, such as those discussed in connection with other figures. Processors <NUM> and <NUM> may exchange data via a point-to-point (PtP) interface <NUM> using point-to-point interface circuits <NUM> and <NUM>, respectively. Processors <NUM> and <NUM> may each exchange data with a chipset <NUM> via individual point-to-point interfaces <NUM> and <NUM> using point-to-point interface circuits <NUM>, <NUM>, <NUM>, and <NUM>. Chipset <NUM> may also exchange data with a co-processor <NUM>, such as a high-performance graphics circuit, machine learning accelerator, or other co-processor <NUM>, via an interface <NUM>, which could be a PtP interface circuit. In alternative embodiments, any or all of the PtP links illustrated in <FIG> could be implemented as a multi-drop bus rather than a PtP link.

Chipset <NUM> may be in communication with a bus <NUM> via an interface circuit <NUM>. Bus <NUM> may have one or more devices that communicate over it, such as a bus bridge <NUM> and I/O devices <NUM>. Via a bus <NUM>, bus bridge <NUM> may be in communication with other devices such as a user interface <NUM> (such as a keyboard, mouse, touchscreen, or other input devices), communication devices <NUM> (such as modems, network interface devices, or other types of communication devices that may communicate through a computer network <NUM>), audio I/O devices <NUM>, and/or a data storage device <NUM>. Data storage device <NUM> may store code <NUM>, which may be executed by processors <NUM> and/or <NUM>. In alternative embodiments, any portions of the bus architectures could be implemented with one or more PtP links.

The computer system depicted in <FIG> is a schematic illustration of an embodiment of a computing system that may be utilized to implement various embodiments discussed herein. It will be appreciated that various components of the system depicted in <FIG> may be combined in a system-on-a-chip (SoC) architecture or in any other suitable configuration capable of achieving the functionality and features of examples and implementations provided herein.

While some of the systems and solutions described and illustrated herein have been described as containing or being associated with a plurality of elements, not all elements explicitly illustrated or described may be utilized in each alternative implementation of the present disclosure. Additionally, one or more of the elements described herein may be located external to a system, while in other instances, certain elements may be included within or as a portion of one or more of the other described elements, as well as other elements not described in the illustrated implementation. Further, certain elements may be combined with other components, as well as used for alternative or additional purposes in addition to those purposes described herein.

Further, it should be appreciated that the examples presented above are nonlimiting examples provided merely for purposes of illustrating certain principles and features and not necessarily limiting or constraining the potential embodiments of the concepts described herein. For instance, a variety of different embodiments can be realized utilizing various combinations of the features and components described herein, including combinations realized through the various implementations of components described herein. Other implementations, features, and details should be appreciated from the contents of this Specification.

Although this disclosure has been described in terms of certain implementations and generally associated methods, alterations and permutations of these implementations and methods will be apparent to those skilled in the art. For example, the actions described herein can be performed in a different order than as described and still achieve the desirable results. In certain implementations, multitasking and parallel processing may be advantageous. Additionally, other user interface layouts and functionality can be supported. Other variations are within the scope of the following claims.

Claim 1:
A hinge apparatus for a foldable display device comprising:
first and second curved rack apparatuses (210a,b), each curved rack apparatus defining an arcuate surface (<NUM>) and an arcuate set of gear teeth (<NUM>) concentric with the arcuate surface (<NUM>), the radius of curvature of the arcuate set of gear teeth (<NUM>) being non-uniform; and
a gear assembly (<NUM>) comprising:
a first helical gear (224a);
a second helical gear (224b);
a third helical gear (<NUM>) coupling the first helical and second helical gears;
a first spur gear (222a) coupling the first helical gear (224a) and the arcuate set of gear teeth (216a) of the first curved rack apparatus (210a); and
a second spur gear (222b) coupling the second helical gear (224b) and the arcuate set of gear teeth (216b) of the second curved rack apparatus.