Flexible display devices

Electronic devices may be provided that contain multiple housing portions. The housing portions may be coupled together using hinges. The hinges may include hinges based on a three-bar linkage, hinges based on a four-bar linkage, hinges with slotted members, hinges formed from flexible support structures, and hinges based on flexible housing structures. Flexible displays may be mounted to the housing portions overlapping the hinges. When the housing portions in a device are rotated relative to each other, the flexible display may bend. The hinge may be configured to allow the flexible display to be placed in a front-to-front configuration in which an active side of the display faces itself or a back-to-back configuration. Engagement structures may be used to help the housing grip external objects and to hold the housing portions together. The hinges may be provided with rotational detents to help hold the flexible display in desired positions.

BACKGROUND

This relates generally to electronic devices, and, more particularly, to electronic devices with flexible displays.

Electronic devices such as cellular telephones, media players, and computers are often provided with displays. For example, electronic devices may be provided with liquid crystal displays. Liquid crystal displays are often mounted under a rigid layer of cover glass. The cover glass protects the liquid crystal display from damage, but the rigid nature of the cover glass and other display layers render the display inflexible.

Flexible display technologies are available that allow displays to be bent. For example, flexible displays may be formed using flexible organic light-emitting diode (OLED) display technology.

It would be desirable to be able to use flexible display technology to provide improved electronic devices.

SUMMARY

Electronic devices may be provided that contain multiple housing portions. The housing portions may include, for example, first and second rectangular housing portions.

The housing portions may be coupled together using hinges. The hinges may include hinges based on a three-bar linkage, hinges based on a four-bar linkage, hinges with slotted members, hinges formed from flexible support structures, and hinges based on flexible housing structures.

Flexible displays may be mounted to the housing portions overlapping the hinges. When the housing portions in a device are rotated relative to each other, the flexible display may bend. Hinges may be configured to allow the flexible display to be placed in a front-to-front configuration in which the active side of the display faces itself or a back-to-back configuration in which the active portions of the display face away from each other. To avoid stretching the display, the display may be tensioned with tensioning structures and dispensed from a roller or an opening in a housing structure.

Engagement structures may be used to help the housing grip external objects and to hold the housing portions in desired positions. The hinges may also be provided with rotational detents to help hold the flexible display in desired positions.

DETAILED DESCRIPTION

An illustrative electronic device with a flexible display is shown inFIG. 1. Electronic device10may be a portable electronic device or other suitable electronic device. For example, electronic device10may be a laptop computer, a tablet computer, a somewhat smaller device such as a wrist-watch device, pendant device, headphone device, earpiece device, or other wearable or miniature device, a cellular telephone, a media player, larger devices such as desktop computers, computers integrated into computer monitors, televisions, set-top boxes or other electronic devices.

Electronic device10may have a flexible display such as flexible display14. Flexible displays such as flexible display14may be based on electronic ink displays, organic light-emitting diode displays, or other suitable flexible displays. Arrangements in which the flexible displays in the electronic devices are formed from organic light-emitting diode displays are sometimes described herein as an example. This is, however, merely illustrative. Flexible display14may be provided using other display technologies if desired.

Device10may include a housing such as housing12. Housing12, which may sometimes be referred to as a case, may be formed of plastic, glass, ceramics, fiber composites, metal (e.g., stainless steel, aluminum, etc.), other suitable materials, or a combination of these materials. Housing12may be provided with features such as buttons16, speaker ports, microphone ports, connector ports such as illustrative connector port24, ports or other structures for accommodating sensors and antennas, or other device features.

Device10may include one or more displays. The displays may include one or more flexible displays such as display14and may include optional rigid displays (e.g., displays mounted under rigid cover glass layers and/or displays with rigid layers of display components).

Displays such as flexible display14of device10inFIG. 1may be bent by moving portions of housing12with respect to each other. Housing12may, in general, have two or more parts that may be moved with respect to each other while bending a portion of flexible display14. In the example ofFIG. 1, housing12has upper portion12A and lower portion12B. Housing portions12A and12B may be coupled to each other using hinge26, so that the relative positions of portions12A and12B may be adjusted by rotation of portions12A and12B with respect to each other. If desired, three or more pieces of housing12may be coupled together using hinges. Coupling mechanisms other than hinges that allow portions12A and12B and optional additional housing portions to move with respect to each other may also be used. TheFIG. 1arrangement in which device10has two housing portions that are connected using hinge structures is merely illustrative.

Hinge26may allow housing portion12A to rotate relative to housing portion12B about axis18. Hinge26may, for example, allow portion12A to rotate in direction20or direction22. When rotated in direction20, housing portion12A may close on top of portion12B to enclose and protect display14. Display14may bend along axis18, so axis18may sometimes be referred to as a bend axis, flex axis, hinge axis, or rotational axis.

Hinge26may allow housing portions12A and12B to be flattened into a planar device configuration of the type shown inFIG. 2. As shown in the side view ofFIG. 2, device10may be placed into a configuration in which display14is substantially planar. In this type of arrangement, display14is not bent in the vicinity of hinge26, but rather is maintained in a flat configuration in which display14and its outermost surface are planar. This type of position may be desirable when a user of device10is viewing a video, text, or graphics over all of display14(i.e., over all of a display surface that spans housing portions12A and12B).

Device10may include internal components36. Components36may include electrical components such as display driver circuitry, one or more batteries, sensors, microphones, speakers, integrated circuits, microprocessors, power management units, radio-frequency transceiver circuitry, baseband processor circuitry, discrete components such as capacitors, resistors, and inductors, switches, vibrators, connectors, printed circuit boards, wires, transmission lines, and other electrical devices. Components36may be mounted on one or more substrates such as substrates34. Substrates34may include rigid printed circuit boards (e.g., boards formed from fiberglass-filled epoxy such as FR4 printed circuit boards on which patterned metal traces have been formed), flexible printed circuit boards (e.g., “flex circuits” formed form sheets of polymer such as polyimide on which patterned conductive traces have been formed), rigid flex (e.g., boards with both rigid portions and flex circuit tails), plastic carriers, or other substrates. Interconnect paths such as paths38may be used to interconnect components36with each other and with components such as display14. Interconnect paths38may include flex circuits (e.g., traces on flex circuits that form signal paths), wires, cables, traces on rigid printed circuit boards and other substrates, or other suitable conductive paths. Using interconnect paths38, signals may be routed between respective components36and signals may be routed from between components36and display14. For example, signals from a display driver integrated circuit may be routed to display pixels and traces in display14.

Hinge26may be based on a flexible material (e.g., a sheet of flexible polymer or metal), may be based on a single-shaft mechanism, may be based on a two-shaft mechanism, may be based on a three-shaft mechanism, or may use four or more shafts (i.e., pins or other structures that support rotational motion about a rotational axis) for allowing housing members12A and12B to move relative to one another. In the example ofFIG. 2, hinge26has a central member28that has two associated shafts. Shaft30is attached between hinge member28and housing portion12A. Hinge member28is attached to housing portion12B by shaft32. The structures for forming shafts such as shafts30and32may be formed from pins, cylindrical rods, or other suitable rotational axis mechanisms for supporting rotational motion about a rotational axis. Hinge26may be made up of structures on side of device10, structures on both sides of device10(e.g., on the opposing ends of hinge axis18), or in more than two locations along axis18.

Because there are three movable parts in this type of hinge mechanism (i.e., housing12A, member28, and housing12B), hinge arrangements of the type shown inFIG. 2are sometimes referred to as three-bar linkages. Hinge26may, in general, be implemented using a two-bar linkage, a three-bar linkage, a four-bar linkage, or a linkage involving more than four bars. Combinations of these linkages may also be used in forming flexible connecting structures between separate housing portions such as housing portions12A and12B (and, if desired, one or more additional housing portions).

As shown inFIG. 2, portions12A and12B of housing12may be separated by a gap such as gap W. Gap W and the mechanism used for hinge28(e.g., a three-bar linkage) may provide sufficient flexibility to allow portions12A and12B to be folded together by moving portions12A and12B in directions40and may provide sufficient flexibility to allow portions12A and12B to be placed in a back-to-back arrangement by moving portions12A and12B in directions42.

When portions12A and12B are folded together, the outer surface of the portion of display14that is supported by housing portion12A faces the outer surface of the portion of display14that is supported by housing portion12B. The outer surface of display14is therefore protected from undesired contact, as shown in the folded arrangement ofFIG. 3. When folded into the configuration ofFIG. 3, bent portion44of display14may be exhibit a bend radius of about 1 mm (e.g., 4 mm or less, 3 mm or less, 2 mm or less, 1 mm or less, or 0.5 mm or less, as examples). Configurations of the type shown inFIG. 3are sometimes referred to as face-to-face configurations, because active surface portions of display14are face to face with each other.

When portions12A and12B are rotated in directions42ofFIG. 2, housing portions12A and12B may be placed in a back-to-back configuration of the type shown inFIG. 4. In this type of configuration, part of display14may be exposed on the outer surface of housing structure12A and part of display14may be exposed on the outer surface of housing structures12B (i.e., the display surface on housing portion12A is oriented back to back with respect to the display surface on housing portion12B).

Engagement features such as engagement features48may be provided on some or all of rear surfaces49of housing structures12A and12B to allow device10to grip external objects such as external object46. External object46may be, for example, an item of the user's clothing. Engagement features48may be roughened surface structures such as teeth. The teeth may be formed as an integral portion of the housing or may be attached to the exterior of the housing. The teeth may be formed from plastic, metal, or other suitable materials. Features48may have a sawtooth profile, a smooth undulating corrugated profile, may be implemented using one or more spikes or hooks, or may be formed using other suitable structures that protrude from the surface of housing12.

When housing portions12A and12B are rotated from a position of the type shown inFIG. 3into a position of the type shown inFIG. 4, ends51of flexible display14may be pulled in directions50. The length of the display (i.e., the distance along the longer lateral dimension of the display between opposing ends51) does not change substantially as the display is flexed. In the housing configuration shown inFIG. 3, display14runs along the opposing inner surfaces of the housing. In the vicinity of bend44, display14covers minimal distance along dimension Z. As a result, the amount of housing surface over which the display extends is minimized. If, however, device10is placed into the position shown inFIG. 4, bent portion44of display will cover a height H along dimension Z. During the process of moving device10from the configuration ofFIG. 3into the configuration ofFIG. 4, one or both ends51of display41may be permitted to slide along dimension X in direction50to accommodate the extra height H.

Any suitable mechanism may be used to allow display14to slide along the surface of housing12to accommodate changes in the configuration of housing12. For example, one end of display14may be tensioned using a tensioning member, while the opposing end of display14is attached to housing12using a rigid attachment mechanism (as an example). As the device is placed into different configurations, the tensioning member may stretch and thereby allow at least a portion of the flexible display to slide relative to the surface of the device.

In this type of arrangement, one end of display14may be tensioned with a tensioning member or both ends of display14may be tensioned with respective tensioning members. The tensioning members may be formed from metal or polymer springs, springs formed from planar elastomeric members that stretch, or other materials that can be placed under tension to tension display14. An arrangement in which device10has been tensioned with a tensioning structure is shown inFIG. 5. As shown inFIG. 5, one end of flexible display14(i.e., end61and the structures adjacent to end61may be attached to the device12in a non-sliding (fixed) arrangement). Screws, adhesive, or other fastening mechanisms may be used in attaching display14to housing12.

In the example ofFIG. 5, end61of display14has been attached to the planar exposed surface of display12A using adhesive54. Adhesive54may be, for example, epoxy, pressure sensitive adhesive, or other suitable adhesive. Tensioning member58has been attached between end60of display14and support structure56. Support structures56may be formed from part of housing12(e.g., an integral portion of housing portion12B), an internal frame structure or other housing structure, or other suitable portion of device10. When tensioned between member56and end60of display14, tensioning member58may pull end60of flexible display14in direction68. Roller64may be mounted on rotational axis member64. Roller64may rotate about rotational axis64to allow display14to slide relative to housing14with minimal friction. A non-rotating member may be used in place of roller64, if desired.

Flexible display14may slide within housing12B in directions66and68when needed to accommodate motion of housings12A and12B, as described in connection withFIGS. 3 and 4. For example, when housing12is folded so that display14is enclosed within housing portions12A and12B as shown inFIG. 3, slack may tend to develop in display14. Accordingly, tensioning member58may pull end60of display14inFIG. 5in direction68. If, on the other hand, housing12is placed into a configuration of the type shown inFIG. 4, tensioning member58may stretch to allow end60of display14move in direction66.

In the illustrative configuration shown inFIG. 5, roller62was used to facilitate the deployment and retraction of end60of flexible display14. If desired, additional rollers and/or other structures for facilitating the dispensing and retraction of flexible display14may be used. For example, a fixed member that has been coated with a low-friction coating may be used to dispense and retract flexible display14, multiple rollers may be used to dispense and retract flexible display14, etc.

FIG. 6is a side view of an illustrative configuration that may be used for device10in which end60of display14is housed within protruding portion83of housing12B and is dispensed without using roller62. Protruding housing portion83may have an opening such as opening81that allows display14to enter and exit housing portion83. When housing portions12A and12B are folded together to place device10in a configuration of the type shown inFIG. 3(in which the display-covered surfaces of device10face each other to protect display14), tensioning member58may retract end60of display14into device housing83in direction82to avoid creating slack in display14. When housing portions12A and12B are rotated away from each other to place device10into a configuration of the type shown inFIG. 4(in which the display-covered surfaces of device10are facing away from each other), spring58may stretch and allow an appropriate portion of display14in the vicinity of end60to exit opening81in protrusion83in direction80, thereby accommodating the need for additional display length.

The edge of display14may be covered with housing features such as ledges or other overlapping display retention structures to help hold display14on the surface of device10. As shown inFIG. 7, housing12may, for example, have portions76that overlap the edges of display14to help hold display14flat against the planar surface of housing12. Portions76may overlap the edges of display14in overlap regions74. The width of overlap regions74may be, for example, more than 4 mm, 4 mm or less, 3 mm or less, 2 mm or less, 1 mm or less, or 0.5 mm or less.

To accommodate sliding motion of display14(e.g., into and out of the page in the orientation ofFIG. 7), a layer of low-friction material70may be placed between display14and the outermost surface of housing12. For example, housing12may have a planar surface such as planar surface71that may be formed form a layer of plastic or metal. To reduce the friction that display14might otherwise exhibit, low-friction material70may be interposed between surface71and display14. Material70may be formed from one or more coating layers on housing12, a layer of low-friction polymer such as a sheet of polytetrafluoroethylene, etc.

FIG. 8is a top view of a portion of device10showing how display14may slide on the surface of housing12while side edge portions of display14are retained using retention features76in regions74. To facilitate even tensioning of leading edge60of display14by tensioning structures58, a display edge stiffening member such as edge stiffening member85ofFIG. 8may be attached to edge60of display14. Edge stiffening member85may be formed from plastic, metal, or other suitable materials. Openings87may be formed in edge stiffening member85to receive hooked features89on tensioning structures58. If desired, engagement features on edge stiffening member85and/or tensioning structures85may be formed using other configurations. The arrangement ofFIG. 8in which edge stiffening member85has holes and tensioning structures85(e.g., springs) have mating hook-shaped features is merely illustrative.

In the example ofFIG. 8, edge stiffening member85is being tensioned using three tensioning structures58(e.g., three springs). Other numbers of tensioning structures58may be used if desired. For example, one spring or other tensioning structure may be used to tension edge stiffening member85, two or more springs or other tensioning structures may be used to tension edge stiffening member85, three or more springs or other tensioning structures may be used to tension edge stiffening member85, etc.

Housing portions12A and12B may be used to place device10in an arrangement of the type shown inFIG. 9in which display14has a non-planar shape other than the back-to-back configuration ofFIG. 4. In an arrangement of the type shown inFIG. 9, one portion of display14(i.e., display portion14A mounted on the surface of housing portion12A) may be viewed by a user on one side of device (i.e., from position VPL), whereas another portion of display14(i.e., display portion14B mounted on the surface of housing12B) may be viewed by a user on the other side of device (i.e., from position VPR). The triangular shape of device10in this type of configuration may allow device10to rest on top of a table or other flat surface, as illustrated by horizontal line91. This configuration may be used, for example, to allow multiple users to use device10simultaneously (e.g., to play a two-person game, to use two separate applications, one of which is displayed on portion14A and another of which is displayed on portion14B, etc.).

In arrangements such as the arrangement ofFIG. 9, hinge26of device10has been illustrated as being implemented using a three-bar linkage. This is merely illustrative. Hinge26may use any suitable type of flexible joint.FIG. 10is a side view of an illustrative device showing how hinge26may be formed using a four-bar linkage having first shaft (rotational axis)88, second shaft (rotational axis90), and third shaft (rotational axis)92. Hinge26may include first hinge member28A and second hinge member28B. There may be identical hinge structures at both ends of the hinge axis of display14.

Only one set of hinge structures (e.g., the right-hand set) is visible in the example ofFIG. 10.

Hinge member28A may be coupled to housing12A at shaft88. Hinge member28B may be coupled to housing12B at shaft92. Shaft90may be used to link hinge member28A and hinge member28B.

When rotating housings12A and12B with respect to each other, the use of the four-bar linkage design for hinge26may provide desirable degrees of freedom. The four-bar linkage design may, as an example, be able to accommodate a range of relative positions for housing members12A and12B without requiring the same amount of sliding motion for display14relative to housing12that might otherwise be involved in bending display14(e.g., when bending display14using a hinge based on a three-bar linkage). In particular, sliding motions94along the surface of housing portion12B ofFIG. 11may be minimized by the use of the four-bar linkage for hinge26. If desired, portion14B may be attached to housing12B using a fixed (non-sliding) arrangement such as an arrangement based on adhesive (e.g., adhesive such as adhesive54).

The side view of device10ofFIG. 12shows how hinge26may be implemented using a slotted member such as hinge member94. As shown inFIG. 12, hinge member94may have slots such as slot96and slot98. Pin (shaft structure100) may be received within slot96(or other opening in member94). Pin (shaft structure102) may be received within slot98(or other opening in member94).

The use of openings in member94such as slots96and98may provide additional degrees of freedom when positioning housing structures12A and12B relative to each other. For example, slots96and98may allow housings12A and12B to be placed in either the face-to-face configuration ofFIG. 3or the back-to-back configuration ofFIG. 4. In a face-to-face configuration of the type shown inFIG. 3, shaft100may be located in position106of slot96and shaft102may slide to position106of slot98. In a back-to-back configuration of the type shown inFIG. 4, shaft100may be located in position104of slot98and shaft102may be located in position104of slot98. There may be identical hinges on both sides of device10. A single set of hinge structures for a single hinge26is shown in the example ofFIG. 12. In configurations with suitable hinge structures such as hinges with slotted hinge members such as hinge member94ofFIG. 12, flexible display14may be fixedly attached to the surfaces of housing members12A and12B. This is because the hinge structures are sufficiently flexible to accommodate the fixed length of display14. The use of flexible display arrangements where the flexible display slides relative to the surface of housing12may therefore not be needed.

In devices10in which display structures such as two or more housing portions such as housings12A and12B can be placed in a variety of different positions relative to each other, it may be desirable to provide hinges26with detents. Detent structures may, for example, be formed using spring-loaded structure.FIG. 13is a side view of an illustrative hinge26of the type that may be provided with a rotational detent. As shown inFIG. 13, device10may have a housing such as housing12. Hinge member110may be used in forming hinge26. In theFIG. 13example, hinge member110rotates around shaft (rotational axis)108so that hinge member110(and any structures attached to member110) may be placed at a variety of rotational angles A with respect to housing12.

To provide rotational detents for hinge26, shaft108may be provided with indentations such as indentations118and122ofFIG. 14. A mating detent biasing structure such as biasing structure121may be used to engage indentations118and122. Biasing structure121may have a body portion120. A cylindrical bore such as bore116may be provided in the interior of body structure120. Ball112may be received within bore116. Spring114may be used to bias ball112in direction123towards shaft108to engage shaft108and retard rotational motion of shaft108. In the example ofFIG. 14, biasing structure121is using ball112to engage indentation118. If member110were to be rotated 180°, biasing structure121would engage indentation122on the opposing side of shaft (pin)108.FIG. 15is a side view of shaft108showing how indent118(and indent122) may have circular outlines for receiving ball112(as an example).

Shaft108may be attached to housing12and biasing structure121may be attached to member110or vice versa. During operation, the detent mechanism may hold housing portions12A and12B in two positions (one associated with indentation118and one associated with indent122). In general, shafts such as shaft108and hinge26may have any suitable number of indentations (e.g., one, two, more than two, three, four or more, and/or five or more). Each indentation may be used in providing a rotational detent at a different respectively angular position A.

There may be one rotational detent in hinge26(e.g., holding the housings in device10at an angle A1with respect to each other), two rotational detents (e.g., at angles A1and A2), or more rotational detents. The detents in hinge26may be used, for example, to hold device housings12A and12B in a position such as the face-to-face position ofFIG. 3, a back-to-back position such as the back-to-back position ofFIG. 4, a planar position (e.g., a position in which display14is held flat in a planar configuration as shown inFIG. 2), an angled (triangular) position of the type shown inFIG. 9in which display surfaces14A and14B are oriented away from each other, a tilted display position of the type shown inFIG. 1, other suitable positions, and/or subsets of these positions. Ball detents or any other suitable detent mechanisms may be used in forming rotational detents for hinge26. The use of ball detents is merely illustrative.

As shown in the side view ofFIG. 16, device10may include a flexible support structure such as support structure124. Flexible display14may be mounted on support structure124(e.g., using adhesive, fasteners, or other suitable attachment mechanisms). Support structure124may, for example, be formed from a planar layer of material, a skeletal structure (e.g., a frame structure), side support members, or other suitable shapes. Support structure124may be formed from a flexible metal, a flexible polymer, a flexible composite structure, other materials, or a combination of these materials. As an example, support structure124may be formed form a flexible sheet metal structure such as a layer of nitinol (nickel titanium).

Structure124may have a thickness of about 1 mm or less, 0.5 mm or less, 0.2 mm or less, etc. Openings may be provided in structure124to reduce weight and/or to increase flexibility. The openings may be, for example, an array of holes. If desired, electrical current may be applied to structure124to ohmically heat structure124. In configurations where structure124is formed from a shape memory alloy such as NiTi (nitinol), CuZnAl, or CuAlNi, the application of heat to structure124may be helpful in restoring a desired shape to structure124(e.g., a planar shape). Electrical current for restoring support structure124to a desired shape after flexing may be applied to structure124using internal device components such as a battery and control circuit (as an example).

Flexible support structure124may be attached to main housing12by molding parts of a plastic housing structure for housing12over support structures124, by welding support structures124to housing structures, by mounting support structure124to housing12using screws or other fasteners, or by using other mounting techniques.

As shown inFIG. 17, a user of device10may bend flexible support structure124to place flexible display14in a desired bent configuration. The illustrative bent configuration ofFIG. 17involves a backwards tilt of display14at an angle B away from planar (flat) display position125. Angle B may be, for example, 0° to 180°. If desired, a user may tilt display14to a position such as position127. In position127, display14is tilted forward from planar display position125by an angle C. Angle C may be, for example, an angle in the range of 0° to 180°.

As shown in the example ofFIG. 18, flexible display14and flexible support structure124may be bent in direction126to move display14and structure124from position PA to position PB. When flexible display and support structure124are in a position such as position PB ofFIG. 18, device10may be placed on a surface such as surface91, so that portion14C of display14may be viewed by a user. If desired, the portion of display14that rests against surface91may be protected by a layer of cover glass and/or by providing housing12with raised peripheral ridge portions that prevent scratching of display14.

As shown inFIG. 19, device10may be provided with engagement features such as hook128and notch132. Hook128may be attached to support structure124or other portion of the housing structures that support display14. Notch132may be configured to receive hook128when display14is bent downwards in direction130. As shown by dashed line136, hook128may mate with notch132when display14has been placed in position134. This type of configuration or other suitable engagement feature arrangement may be used in holding display14into a back-to-back position (i.e., a configuration in which the folded portion of display14is in position134ofFIG. 19and is facing upwards while the unfolded portion of display14is facing downwards). The use of engagement features based on a hook-and-notch arrangement is merely illustrative. Other types of engagement features (e.g., engagement features129and131in the example ofFIG. 19) may be used if desired (e.g., magnetic structures, snaps, hook-and-loop fastener material, other interlocking shapes, etc.).

As shown inFIG. 20, device10may have a hinge that is formed from a flexible portion of housing12. In the configuration of device10that is shown inFIG. 12, housing12has first portion12A and second portion12B that are interconnected using hinge26. Components144may be mounted in housing12. For example, components144may be mounted in the interior of housing portion12A and/or in the interior of housing portion12B. Components144may be mounted on substrates such as rigid printed circuits boards, flexible printed circuit boards, plastic carriers, or other substrates (shown as substrates142inFIG. 20). Interconnection paths formed from flex circuit cables, wires, interconnect traces on printed circuit boards and other substrates, and other interconnect paths may be used in interconnecting components144and flexible display14. For example, flexible communications path140may be coupled between substrate142in housing portion12A and substrate142in housing portion12B. Path140may be connected to traces on the substrate in housing portion12A at connection point146and may be connected to traces on the substrate in housing portion12B at connection point148. The traces on the substrates may be used to interconnect components144with each other and to path140. Components144may include components such as connectors, integrated circuits (e.g., display driver circuitry for controlling display14), discrete components such as inductors, resistors, and capacitors, sensors, status indicator lights, cameras, microphones, speakers, antennas, batteries, etc.

To facilitate bending of display14and housing12in the vicinity of hinge26, housing12may, as an example, be formed from a flexible material. Examples of flexible materials that may be used in forming housing12include flexible polymers, composite structures (e.g., fiber-based composites, fiber-impregnated polymers, etc.), fabrics, and flexible metals. When housing portions12A and12B are rotated relative to each other around hinge axis18, housing12may flex.

Inflexible structures such as structures138may be used to locally strengthen the walls of housing12in regions of housing12away from hinge26. For example, housing12may be provided with rigid support structures such as support structures138. Structures138may be formed from glass, ceramic, metal, fiber-composites, other suitable materials, combinations of these materials, or other suitable materials. Structures138may be configured to form rigid box-shaped shells or shells of other shapes that partly or completely surround and protect internal components144in housing portions12A and12B from damage when the flexible material of housing12is being used as a hinge and is being flexed (with flexible display14) about axis18. When device10is flexed around axis18, the flexible portions of housing12that form hinge26may flex. Recessed region138may be provided in housing12to facilitate flexing of housing12. As device10is flexed, flexible communications path140may flex, while maintaining an electrical pathway for signals passing between housing portions12A and12B.

FIG. 21shows how a device having a hinge formed from a flexible portion of housing12such as device10ofFIG. 20may appear when housing portions12A and12B have been manipulated to flex hinge26and place flexible display14in a face-to-face configuration.FIG. 22shows how device10ofFIG. 20may appear when housing portions12A and12B have been manipulated to place flexible display14in a back-to-back configuration. In configurations of the type shown inFIGS. 21 and 22, engagement features129and131(e.g., magnetic structures, hook-and-loop fasteners, hook and notch structures, other mating structures, or other suitable engagement features) may be used in holding housing portions12A and12B in desired positions.

FIG. 23is a side view of an illustrative electronic device with three separate housing portions12A,12B, and12C. As shown inFIG. 23, housing portions12A and12B in device10may be coupled using hinge26A and housing portions12B and12C may be coupled using hinge26B. Additional housing portions may be provided in device10if desired, as indicated by dots200. Hinges26may be formed form flexible housing portions, from three-bar or four-bar linkages, from members containing slots (as shown inFIG. 23), from flexible metal layers or other sheets of flexible support structure material, from other hinge structures, or from combinations of such structures.

When it is desired to place a device such as device10into a folded configuration, housing portion12A may be rotated relative to housing portion12B in direction202and housing portion12C may be rotated in direction204relative to housing portion12B (as an example). Following folding in this way, electronic device10may have a configuration of the type shown inFIG. 24. In this type of configuration, the portions of flexible display14that are associated with housing portions12A and12B may have a face-to-face configuration, whereas the portions of flexible display14that are associated with housing portions12B and12C may have a back-to-back configuration. If desired, hinges26A and26B may be configured so that housing portions12A and12C can both fold inwardly onto housing portion12B. The arrangement shown inFIG. 24is merely illustrative.

Device10may, in general, have any suitable hinge structure (a three-bar linkage, a four-bar linkage, a flexible housing hinge, hinge structures with rotational detents, hinges based on slotted members, etc.), any suitable housing structure (e.g., metal, plastic, rigid, flexible, composite, etc.), any suitable number of housing portions (two, three, four, two or more, three or more, four or more), any suitable type of flexible display attachment mechanism (fixed, sliding, fixed at one end, sliding at another), any suitable number of detents, any suitable type of tensioning structures (e.g., springs, etc.), any suitable type of flexible display dispensing and retracting structures (roller-based, housing-protrusion-based, etc.), any suitable type of housing structure engagement features (magnetic structures, hook-and-loop fastening material, hooks and recesses, etc.), any suitable type of external object engagement features (e.g., raised housing ridges for gripping cloth), other suitable features, combinations of any or all of these features, etc.