Opening and closing device and terminal device

An opening and closing unit which satisfies required functions of an opening and closing unit and is able to more smoothly bend/unfold a terminal, link parts are slidable with rotation relative to an attaching member. Link parts are slidable with rotation relative to an attaching member. Central parts are provided between the link members and the link parts, with one end portion thereof being slidable relative to the link members with rotation, and other end portion thereof being slidable relative to the link parts with rotation. The friction generating portions are provided between an attaching part and central parts, and apply a resistance force against a rotation of the central members relative to the attaching part. The friction generating portions are provided between an attaching part and central parts, and apply a resistance force against a rotation of the central parts relative to the attaching part.

FIELD OF THE INVENTION

The invention relates to an opening and closing device for supporting a sheet-like flexible display panel, e.g. organic EL (electroluminescence) panel, LED panel, etc., provided over both a first casing and a second casing to bend and unfold it, and to a terminal device using such an opening and closing device.

BACKGROUND ART

In recent years, a terminal device such as smartphone, tablet PC, game machine, cellular phone etc. is being put into practical use, wherein a flexible display panel, e.g. organic EL panel, LED panel, etc. is provided to cross both a first casing and a second casing, so that the flexible display panel is bent into twofold while out of use, and that it is unfolded into a single plane in use. For such a terminal device, an example of an opening and closing device for flexibly coupling a first casing and a second casing is disclosed in JP Laid-Open Patent Application No. 2014-161009.

In an opening and closing device according to JP Laid-Open Patent Application No. 2014-161009, a first casing and a second casing are flexibly coupled by resin bellows structure to support an organic EL panel. Still further, when the first casing and the second casing overlap each other and the organic EL panel is bent into a folded state, the opening and closing device forms a curvature in the shape of cylindrical surface to give the organic EL panel a predetermined curvature radius. Furthermore, in the opening and closing device according to JP Laid-Open Patent Application No. 2014-161009, a reinforced beam made of shape-memory alloy is provided in curving direction so as to cross the resin bellows structure. The reinforced beam can be freely plastically deformed to maintain its shape, so that the first casing and the second casing can be held at any opening angle.

In an opening and closing device, wherein a first casing and a second casing are coupled to support a flexible display panel, it is preferable to be able to realize a curvature at a predetermined curvature radius, when the flexible display panel is bent into a folded state. This is because some properties of the flexible display panel may be impaired by folding it to a curvature radius smaller than what is acceptable. Furthermore, in the opening and closing device, a bending surface supporting the flexible display panel preferably has a constant length as accompanied by a bending/unfolding of the flexible display panel. This is because some properties of the flexible display panel may be impaired by a remarkable fluctuation in a length of the bending surface as accompanied by the bending/unfolding, which results in excessive force acting on the flexible display panel. Furthermore, in the opening and closing device, the first casing and the second casing supporting the flexible display panel can be preferably held at any opening angle. If the opening and closing device itself has a function of holding the unfolding (it is also referred to as opening and closing) angle, it can maintain a state of the flexible display panel being bent into twofold or unfolded into a single plane, even without hold on the flexible display panel by hands or tool.

However, a resin bellows structure as disclosed in JP Laid-Open Patent Application No. 2014-161009 has a different length in a closed state when the first casing and the second casing overlaps each other, from an opened state when the first casing and the second casing are unfolded to form a plane. In this manner, if the flexible display panel is supported on bending parts of the bellows structure, a tension force is applied on the flexible display panel in its closed state, while a gap is generated between the flexible display panel and the bellows structure in its opened state.

To this end, another opening and closing device has been proposed, wherein a plurality of link members are coupled so as to be slidable with rotation in a bending direction, and wherein an arc-shaped bending surface is formed by an enveloping surface inside the plurality of link members. Still further, it has been further proposed that a coupling portion for adjacent link members is tightly fitted to generate a friction force, such that the first casing and the second casing can be held at any opening angle.

However, if a coupling portion for adjacent link members undergoes an interference fit, a mechanism including such cannot be a link mechanism, the adjacent link members cannot smoothly slide relative to each other in a bending direction, so that the entire plurality of link members cannot smoothly generate a bending or release from bending.

SUMMARY OF THE INVENTION

An object of the invention is to provide an opening and closing device using a flexible display panel provided over both a first casing and a second casing, which has a simple structure, and satisfies required functions as listed above, as well as enables the flexible display panel to be more smoothly bent/unfolded.

An opening and closing device according to the invention openably and closably couples a first casing and a second casing, and forms an arc-shaped cross section in a closed state to support a flexible display panel provided to cross both the first casing and the second casing. Furthermore, it comprises a first attaching member fixable to the first casing, a first link member slidable relative to the first attaching member with rotation, a second attaching member fixable to the second casing, a second link member slidable relative to the second attaching member with rotation, a central member provided between the first link member and the second link member, wherein its one end portion is slidable relative to the first link member with rotation, and other end portion is slidable relative to the second link member with rotation, first friction generating means provided between the first attaching member and the central member for applying a resistance force to a rotation of the central member relative to the first attaching member, and second friction generating means provided between the second attaching member and the central member for applying a resistance force to a rotation of the central member relative to the second attaching member.

According to the invention, it is possible to provide an opening and closing device using a flexible display panel provided over both a first casing and a second casing, which has a simple structure, and satisfies required functions as listed above, as well as enables the flexible display panel to be more smoothly bent/unfolded.

EMBODIMENTS

Embodiments of the invention will be described in detail in reference to attached drawings. In the following embodiments, the entire structure composed of a plurality of link members coupled to each other forms a curvature and release from curvature, as accompanied by opening and closing of the terminal device. Furthermore, in adjacent link members, an arc convex portion formed on one of them is fitted into an arc groove formed on the other, so that a hinge (rotation portion) is formed without using a hinge shaft.

FIGS. 1A, 1B and 1Cshow an explanatory view of opening angles of a terminal device according to Embodiment 1.FIG. 1Ashows 0 degree,FIG. 1B—90 degrees, andFIG. 1C—180 degrees. As show inFIG. 1A, a terminal device100according to Embodiment 1 is a PC display on which a flexible organic EL display panel is mounted. The terminal device is provided with the flexible display panel which extends to cross both casings sandwiching an opening and closing device10which can be folded to overlap each other. The opening and closing device10has a cylindrically bent surface formed between the both casings so as to support the flexible display panel.

In a terminal device100according to Embodiment 1, a first casing101and a second casing102are openably and closably coupled to each other by a pair of opening and closing devices103,104. The first casing101is an aluminum alloy box body in which a wireless communication antenna and a circuit board (not shown) are built-in. The second casing102is an aluminum alloy box body in which a secondary battery (not shown) is built. In a closed state, where the first casing101and the second casing102are opened to 0 degree, the opening and closing devices103,104form enveloping surfaces both on an inner surface and an outer surface.

As show inFIG. 1B, a flexible organic EL panel105is attached onto a first casing101, a second casing102and opening and closing devices103,104so as to extend over and cover their entire inner surfaces. The organic EL panel105is an organic EL imaging element, wherein its entirety is bent in a cylindrical shape, following envelop surfaces of the inner surfaces of the opening and closing devices103,104. The organic EL panel105is powered by a secondary battery built in the second casing102. The organic EL panel105is driven by a circuit board built in the first casing101to display an image. In the meantime, the organic EL panel105is very thin and sheet-shaped, with the element itself being 0.05 to 0.2 mm thick, but can be the one with soft spacer being disposed so that its thickness can be adjusted to 0.5 to 2.0 mm.

When a second casing102is opened relative to a first casing101, opening and closing devices103,104can maintain any opening angle within a range of 0 to 180 degrees of the second casing by friction generating portions (40) to stop the second casing. The opening and closing devices103,104both form cylindrical surface-shaped envelop surfaces on their inner surfaces to support an organic EL panel105, even if a second casing102is opened 90 degrees.

As shown inFIG. 1C, opening and closing devices103,104both form on their inner surfaces flat surfaces having the same height as a first casing101and a second casing102, when a second casing102is opened 180 degrees. A first casing101, the second casing102and the inner surfaces of the opening and closing devices103,104form flat surfaces to support a lower surface of an organic EL panel105at an identical height.

On the other hand, when opening and closing devices103,104are composed of normal link members, that is, a caterpillar-shaped structure in which a plurality of link members disposed along a bent surface are respectively coupled via a hinge shaft, a length along a bending of inner surfaces fluctuates as accompanied by opening and closing of the opening and closing devices. On the other hand, the length along the bending of the inner surfaces is kept constant as accompanied with opening and closing of the opening and closing devices, on envelop surfaces on the center of the hinge shafts arranged along the bent surface in the shape of circumference. Therefore, a structure for rotating adjacent link members relative to each other is constructed without hinge shaft, in the opening and closing devices103,104, so that the space in which a hinge shaft should be disposed as in prior arts is given to an organic EL panel105. In the opening and closing devices103,104, a central position for rotation of adjacent link members relative to each other is set on the inner surfaces of the opening and closing devices103,104, so that the length along the bending of the bent surfaces formed by the inner surfaces (the length along the bent surfaces at a height position at which an organic EL element of the organic EL panel is disposed, if the thickness of the organic EL panel is taken into consideration) does not have so remarkable fluctuations.

FIGS. 2A and 2Bshow an explanatory view of an opening and closing device.FIG. 3shows an exploded perspective view of an opening and closing device.FIG. 2Ashows an attached state, andFIG. 2B—an assembled state. As shown inFIG. 2A, opening and closing devices103,104openably and closably couple a first casing101and a second casing102. The opening and closing devices103,104are assembled using common components. Since both the opening and closing devices103,104are identical parts, so they are collectively referred to as opening and closing device10in the following.

As shown inFIG. 2B, an opening and closing device10openably and closably couple a first casing101and a second casing102. The opening and closing device10is bisymmetrically assembled using parts bisymmetrically formed about a central line H-H. Since in the opening and closing device10the parts bisymmetrically formed about a central line H-H have substantially identical structure, two sets of bisymmetrical components are denoted with reference numerals respectively having common ones places and different tens places (20to26;30to36).

As shown inFIG. 3, an attaching member11is integrally attached to a first casing101by inserting a retention pin101binto an attaching hole11aas it overlaps an attaching hole101aof the first casing101, and then caulking a tip of the retention pin101b. An attaching member12is integrally attached to a second casing102by inserting a retention pin102binto an attaching hole12aas it overlaps an attaching hole102aof the second casing102, and then caulking a tip of the retention pin102b. Therefore, the attaching member11being an example of a first attaching member is fixable to the first casing101, and the attaching member12being an example of a second attaching member to the second casing102.

An attaching member11is integrally fixed to a link supporting member13by inserting a retention pin13binto an attaching hole11bas it overlaps an attaching hole13aof the link supporting member13, and then caulking a tip of the retention pin13b. An attaching member12is integrally fixed to a link supporting member14by inserting a retention pin14binto an attaching hole12bas it overlaps an attaching hole14aof the link supporting member14, and then caulking a tip of the retention pin14b.

A link supporting member25is integrally fixed to the link supporting member13by fastening a male screw13das is passed through a circular hole25dof the link supporting member25to female screw13cof the link supporting member13. A link supporting member26is integrally fixed to the link supporting member14by fastening a male screw14das is passed through a circular hole26dof the link supporting member26to female screw14cof the link supporting member14. A link supporting member35is integrally fixed to the link supporting member13by fastening a male screw13fas is passed through a circular hole35dof the link supporting member35to female screw13eof the link supporting member13. A link supporting member36is integrally fixed to the link supporting member14by fastening a male screw14fas is passed through a circular hole36dof the link supporting member36to female screw14eof the link supporting member14.

A coupling portion20couples an attaching member11and an attaching member12by disposing link members22,24between link supporting members25,26and a central member21. The coupling portion20forms arc-shaped envelop surfaces on the inside and the outside of an opening and closing device10as accompanied by a rotation of the attaching member12relative to the attaching member11, wherein the surfaces smoothly couple the attaching member11and the attaching member12. A coupling portion30couples an attaching member11and an attaching member12by disposing link members32,34between link supporting members35,36and a central member31. The coupling portion30forms arc-shaped envelop surfaces on the inside and the outside of an opening and closing device10as accompanied by a rotation of the attaching member12relative to the attaching member11, wherein the surfaces smoothly couple the attaching member11and the attaching member12.

A central member21of a coupling portion20and a central member31of a coupling portion30are integrally formed as a central block15being a single component sharing a circumferential surface on the outside and a flat surface on the inside. The central member21and the central member31are located on end portions on the right and the left to integrally rotate.

Central members21,31,23,33, link members22,32, link members24,34, link supporting members13,14, link supporting members25,35, and link supporting members26,36have their respective inner and outer shapes so as to form envelop surfaces in the shape of circular surface on the outer surface and the inner surface of an opening and closing device10. A central block15, the link supporting members13,14, the link supporting members25,35,26,36, the link members22,32, the link members24,34, and the central members23,33are made up of MIM (metal injection mold) part, a ferrous metal, a stainless steel, titanium alloy and so on, in consideration of strength of each coupling portion.

FIGS. 4A and 4Bshow an exploded perspective view of coupling portions.FIG. 4Ashows a right-side coupling portion, andFIG. 4B—a left side coupling portion. As shown inFIG. 3, link supporting members25,35are fixed to an attaching member11via a link supporting member13. Link supporting members26,36are fixed to an attaching member12via a link supporting member14.

As shown inFIGS. 4A and 4B, in link members24,34, short arc convex portions24a,34aare loosely fitted into long arc grooves25m,35mof the link supporting members25,35, while short arc convex portions24b,34bon the other side are loosely fitted into long arc grooves23a,33aof a central member23. In this manner, the link members24,34are slidable in an arc shape, as their both ends are guided by the arc grooves25m,35mand the arc grooves23a,33a. Therefore, the link members24,34being examples of first link members are slidable with rotation relative to the link supporting members25,35.

In link members22,32, short arc convex portions22a,32aare loosely fitted into long arc grooves26m,36mof the link supporting members26,36, while short arc convex portions22b,32bon the other side are loosely fitted into long arc grooves21b,31bof a central member21,31. In this manner, the link members22,32are slidable in an arc shape, as their both ends are guided by the arc grooves26m,36mand the arc grooves21b,31b. Therefore, the link members22,32being examples of second link members are slidable with rotation relative to the link supporting members26,36.

In central members23,33, short arc convex portions23b,33bare loosely fitted into short arc grooves21a,31aof central members21,31. In this manner, the central members23,33integrally rotate with the central members21,31, with no relative rotation nor slide to the latter. The central members23,33and the central members21,31being examples of central members couple link members24,34and link members22,32. In the central members21,31, short arc portions22a,32aof link members22,32are loosely fitted onto long arc convex grooves21b,31b. In the central members23,33, short arc portions24a,34aof link members24,34are loosely fitted onto long arc convex grooves23a,33a. Therefore, in the central members21,31, their one end portions are slidable relative to link members24,34with rotation, and their other end portions are slidable relative to the link members22,32with rotation.

Arc grooves25m,35mof link supporting members25,35as well as arc grooves23a,33aof central members23,33are formed in a circumferential shape, such that the center of a circumference coincides with inner surfaces of link supporting members25,35and the central members23,33. Arc grooves25m,35mof link supporting members26,36as well as arc grooves21b,31bof central members21,31are formed in a circumferential shape, such that the center of a circumference coincides with inner surfaces of the link supporting members26,36and the central members21,31. In this manner, an inner surface of an opening and closing device10formed as envelop surfaces of these elements and link members22,32,24,34has a length which undergoes small fluctuations along a curvature as accompanied by opening and closing.

To prevent an organic EL panel (105) disposed so as to overlap the inner surface from being drawn or compressed, as accompanied by opening and closing of an opening and closing device10, envelop surfaces formed on the inner surface preferably have a constant length in a circumferential direction as accompanied by opening and closing of an opening and closing device10. To this end, as shown inFIGS. 4A and 4B, a combination of long circumferential grooves31b,36m,33a,35mand a short circumferential projections32a,32b,34a,34bcontrols a rotation of link members22,32,24,34. If such rotation is controlled by hinge shafts, they will be obstacles to design of an organic EL panel105, which cannot be thus provided at a height position at which its length in a circumferential direction is constant as accompanied by opening and closing of an opening and closing device10.

On the other hand, a normal opening and closing device in which adjacent link members are coupled via hinge shafts would be capable of maintaining an opening angle of the opening and closing device by providing friction generating portions around the hinge shafts. However, in an opening and closing device10, arc convex portions are held in arc grooves to rotate adjacent link members relative to each other, thus the opening and closing device has no hinge shafts; therefore, friction generating portions cannot be provided around hinge shafts. Still further, in the opening and closing device10, to increase a friction between arc grooves and arc convex portions to maintain an opening angle of the opening and closing device10, a smooth slide movement of adjacent link members is disturbed to made difficult even opening and closing of the opening and closing device10. Therefore, in Embodiment 1, a friction generating portion is provided between one link member and the one next to the next link member. In this manner, a smooth slide movement is possible between adjacent link members, so that the opening and closing device10can be smoothly opened and closed.

FIG. 5shows an exploded perspective view of a friction generating portion.FIG. 6shows an explanatory view of a structure and an attachment of a friction generating portion.FIG. 7shows a cross section of a friction generating portion. As shown inFIG. 3, each friction generating portion40jumps over link members22,32,24,34to couple an attaching member11, a central block15and an attaching member12. As shown inFIG. 5, each friction generating portion40has its L-shaped shafts42,45located on the attaching member11, its U-shaped shafts41,49located on the central block15and its L-shaped shafts43,46located on the attaching member12.

As shown inFIG. 3, each friction generating portion40is attached by plates51,52,53to the attaching member11, the central block15and the attaching member12, so as to overlap them. The plate51fixed integrally with the attaching member11by fastening a male screw11das is passed through a circular hole51ato a female screw11cof the attaching member11. The plate52fixed integrally with the attaching member12by fastening a male screw12das is passed through a circular hole52ato a female screw12cof the attaching member12. The plate53fixed integrally with the central block15by fastening a male screw15bas is passed through a circular hole53ato a female screw15aof the central block15.

FIG. 6illustrates in detail an attached state of L-shaped shafts42,43,45,46; here, in order to facilitate an understanding of relationship between components, several parts shown inFIG. 3are omitted. As shown inFIG. 6, an end portion42bof an L-shaped shaft42is slidably held between a plate51and a slide surface11eof an attaching member11. An end portion43bof an L-shaped shaft43is slidably held between a plate52attached onto a slide surface12eof an attaching member12and the slide surface12e. Equally, an end portion45bof an L-shaped shaft45is slidably held between the plate51and a slide surface11fof the attaching member11. An end portion46bof an L-shaped shaft46is slidably held between the plate52and a slide surface12f. A groove portion15eof the central block15loosely holds a portion bent in the U shape of a U-shaped shaft41. A groove portion15fof the central block15loosely holds a portion bent in the U shape of a U-shaped shaft49.

As shown inFIG. 7, friction generating portions40being an example of first friction generating means couple an attaching member11and a central block15by friction bearings47, and apply a resistance force against a rotation of central members21,31relative to the attaching member11. The friction bearings47couple L-shaped shafts43,46and U-shaped shafts41,49. The friction bearings47form a circular hole by curling end portions47b,47c,47dof an elastic plate material (stainless)47a, and hold the L-shaped shafts43,46and the U-shaped shafts41,49respectively in the circular hole by interference-fit.

Friction generating portions40being an example of second friction generating means couple an attaching member12and a central block31by friction bearings48, and apply a resistance force against a rotation of central members21,31relative to the attaching member12. The friction bearings48couple L-shaped shafts42,45and U-shaped shafts41,49. The friction bearings48form circular holes by curling end portions48b,48c,48dof an elastic plate material (stainless)48ain a cylindrical shape, and holds the L-shaped shafts43,46and the U-shaped shafts41,49respectively in the circular holes by interference-fit.

End portions47bof the friction bearings47for holding the L-shaped shafts42,45are slidably attached to the attaching member11by a plate51shown inFIG. 3. End portions48bof the friction bearings48for holding the L-shaped shafts43,46are slidably attached to the attaching member12by a plate52shown inFIG. 3. End portions47c,47d,48c,48dof the friction bearings47,48for holding the U-shaped shafts41,49are attached to a central block15by a plate53.

End portions41a,49aof U-shaped shafts41,49being examples of first friction members are provided on central members21,31so as to restrict a rotation relative to the central members21,31. Each of the friction bearings47has one end portion47battached to an attaching member11, and other end portions47c,47dfitted onto the U-shaped shafts41,49to apply friction force being a resistance force. End portions41b,49bof the U-shaped shafts41,49being examples of third friction members are provided on the central members21,31so as to restrict a rotation relative to the central members21,31. Each of friction bearings48has an end portion48battached to an attaching member12, and end portions48c,48dfitted onto the U-shaped shafts41,49to apply friction force being a resistance force. The end portions42a,45aof the L-shaped shafts42,45being examples of fifth friction members are provided on the attaching member11so as to restrict a rotation relative to the attaching member11, and fitted into the end portions47bof the friction bearings47to apply a friction force being a resistance force. The end portions43a,46aof the L-shaped shafts43,46being examples of fifth friction members are provided on the attaching member12so as to restrict a rotation relative to the attaching member12, and fitted into the end portions48bof the friction bearings48to apply a friction force being a resistance force.

On the other hand, in an opening and closing device10, envelop surfaces formed by a plurality of link members substantially correspond to centers of a relative rotation of adjacent link members. In other words, imaginary hinge shafts in a relative rotation of adjacent link members are disposed along envelop surfaces formed by a plurality of link members on their inside. Then, an organic EL panel105is disposed at a height position at which a length along a bending does not fluctuate so much as accompanied by an opening and closing of the opening and closing device10. In this manner, L-shaped shafts42,43,45,46and U-shaped shafts41,49of friction generating portions40cannot be disposed at positions of imaginary hinge shafts, but displaced far outward from such positions. Therefore, a perimeter of a circumferential surface on which the L-shaped shafts42,43,45,46and the U-shaped shafts41,49are disposed largely fluctuates as accompanied by an opening and closing of the opening and closing device10. However, since the U-shaped shafts41,49are fixed to a central member21, it is impossible to move along a bending of the inner surfaces. In this manner, if then the L-shaped shafts42,43,45,46of the friction generating portions40are fixed to attaching members11,12, the friction generating portions40diagonally lock a distance between two attaching members11,12, so that it is difficult to open and close the opening and closing device10. Therefore, in an opening and closing device10, end portions42b,43b,45b,46bof the L-shaped shafts42,43,45,46are attached along the attaching members11,12so as to be slidable in a direction along the bending.

End portions42b,45bof L-shaped shafts42,45are slidably held in a space11hof an attaching member11. The L-shaped shafts42,45slide along the attaching member11in the space11has accompanied by a rotation of central members21,31relative to the attaching member11. End portions43b,46bof L-shaped shafts43,46are slidably held in a space12hof an attaching member12. The L-shaped shafts42,45slide along the attaching member12in the space11has accompanied by a rotation of central members21,31relative to the attaching member12.

End portions41a,49aof U-shaped shafts41,49and end portions41b,49bof the U-shaped shafts41,49are respectively composed of the U-shaped shafts41,49being single pieces. The end portions41a,49aof U-shaped shafts41,49and the end portions41b,49bof the U-shaped shafts41,49are respectively composed of parts facing each other in parallel of a metal wire bent in a U-shape. Friction bearings47,48are composed of elastic plate materials, wherein their respective cross sections are bent so as to pinch cross sections of a metal wire.

In friction generating portions40, first friction generating means and second friction generating means are integrally coupled on a central block15, by the U-shaped shafts41,49. A plurality of sets of friction generating portions40are disposed between a pair of coupling portions20,30, wherein each of coupling portions is composed of an attaching member11, link members24,34, an attaching member11, link members22,32and a central block15. Since in friction generating portions40, friction resistances have fluctuations due to fluctuations in diameters of the U-shaped shafts41,49and of L-shaped shafts42,43,45,46, as well as those of circular holes of the friction bearings47,48, a combination of three friction generating portions40is selected such that a total rotation resistance is equal on each of rotation centers of the friction generating portions40.

(Cross Sections of Coupling Portions for Different Opening Angles)

FIG. 8shows an explanatory view for nomenclature of respective cross sections of an opening and closing device.FIGS. 9A, 9B, 9C, 9D and 9Eshow respective cross sections of coupling portions at an opening angle of 0 degree.FIGS. 10A, 10B, 10C, 10D and 10Eshow respective cross sections of coupling portions at an opening angle of 90 degrees.FIGS. 11A, 11B, 11C, 11D and 11Eshows respective cross sections of coupling portions at an opening angle of 180 degrees.FIG. 11Ashows an A-A cross section,FIG. 11B—a B-B cross section,FIG. 11C—a C-C cross section,FIG. 11D—a D-D cross section andFIG. 11E—an E-E cross section.

As shown inFIG. 8, cross sections are defined at respective positions A to E of coupling portions; then cross sections for different opening angles are shown inFIGS. 9A to 11E.

As shown inFIGS. 9A to 11A, short arc convex portions24a,34aof link members24,34are loosely fitted into long arc grooves25m,35mof link supporting members25,35, so that these link members are slidable with rotation relative to the link supporting members25,35. As shown inFIGS. 9B, 10B and 11B, short arc convex portions22a,32aof link members22,32are loosely fitted into long arc grooves25m,35mof link supporting members26,36, so that these link members are slidable with rotation relative to the link supporting members26,36.

As shown inFIGS. 9C, 10C and 11C, short arc convex portions24b,34bof link members24,34are loosely fitted into long arc grooves23a,33aof central members23,33, so that these link members are slidable with rotation relative to the central members23,33. As shown inFIGS. 9E, 10E and 11E, short arc convex portions22b,32bof link members22,32are loosely fitted into long arc grooves21b,31bof central members21,31, so that these link members are slidable with rotation relative to the central members21,31. The central members23,33are fixed to central members21,31, by loosely fitting arc convex portions23b,33binto arc grooves21a,31aof the central members21,31.

(Cross Sections of Friction Generating Portions for Different Opening Angles)

FIGS. 12A, 12B, 12C and 12Dshow respective cross sections of a friction generating portion at an opening angle of 0 degree.FIGS. 13A, 13B, 13C and 13Dshow respective cross sections of a friction generating portion at an opening angle of 90 degrees.FIGS. 14A, 14B, 14C and 14Dshow respective cross sections of a friction generating portion at an opening angle of 180 degrees. InFIGS. 12A to 14D,FIGS. 12A, 13A, 14Ashow a perspective view on an F-F cross section,FIGS. 12B, 13B, 14Bshow an F-F cross section, FIGS.12C,13C,14C show a perspective view on a G-G cross section, andFIGS. 12D, 13D, 14Dshow a G-G cross section.

As shown inFIG. 8, cross sections are defined for different positions A to E of friction generating portions; then cross sections for different opening angles are shown inFIGS. 12A to 14D. As shown inFIGS. 12A to 14A, a U-shaped shaft41is held by interference-fit by end portions47d,48dof friction bearings47,48to generate a friction with the friction bearings47,48. A U-shaped shaft49is held by interference-fit by end portions47c,48cof friction bearings47,48to generate a friction with the friction bearings47,48. This arrangement secures a resistance against a force for rotating the friction bearings47,48relative to a central block15, that is a force for rotating an attaching member11relative to a central block15.

L-shaped shafts42,45are held by interference-fit by end portions47bof friction bearings47to generate a friction with the friction bearings47. L-shaped shafts43,46are held by interference-fit by end portions48bof friction bearings48to generate a friction with the friction bearings48. This arrangement secures a resistance against a force for rotating the friction bearings47,48relative to attaching members11,12, that is a force for rotating an attaching member11relative to a central block15.

Therefore, to change opening angles of the attaching member11and the attaching member12, it is necessary to overcome frictions of end portions47b,47c,47d,48b,48c,48dof the friction bearings47,48and to rotate U-shaped shafts41,49and L-shaped shafts42,43,45,46. Accordingly, an opening and closing device10is held at any opening angle in a range of 0 to 180 degrees of an opening angle of an attaching member11and an attaching member12.

To prevent an organic EL panel105disposed on the inner surface of an opening and closing device10from being drawn or compressed, as accompanied by opening and closing of the opening and closing device10, envelop surfaces inside a plurality of link members (21,23,22,24,25,26;31,33,32,34,35,36) formed on the inner surface of the opening and closing device10preferably have a constant length in a bending direction as accompanied by opening and closing of an opening and closing device10. The opening and closing device10uses no hinge shafts for coupling adjacent link members, and generates a relative rotation between adjacent link members by sliding arc convex portions as guided in long arc grooves; in this manner, it forms on its inside envelop surfaces having a constant length in a circumferential direction. Furthermore, as shown inFIGS. 12A, 12B, 12C, 12E, the opening and closing device10is configured to be opened to 0 degree, when arc convex portions knock against one end portions of arc grooves. Still further, as shown inFIGS. 14A, 12B, 12C, 12E, the opening and closing device10is configured to be opened to 180 degrees, when arc convex portions knock against other end portions of arc grooves. A length of respective arc grooves are configured to rotate 180 degrees/4, that is 45 degrees, the arc convex portions to be inserted. Therefore, the arc grooves function as restricting means KS for restricting a rotation angle of adjacent link members within a predetermined range.

On the other hand, envelop surfaces along end portions47b,47c,47d,48b,48c,48dof the friction bearings47,48are disposed outward of those formed on the inner surface of the opening and closing device10, so that a length in a bending direction fluctuates as accompanied by an opening and closing of the opening and closing device10.

Here, the end portions47b,47c,47d,48b,48c,48dof the friction bearings47,48are fixed to a central block15, so that they cannot move in a circumferential direction of their envelop surfaces. In this manner, the end portions47b,48bmove relative to attaching members11,12, as accompanied by opening and closing of the opening and closing device10, so that they follow a length of envelop surfaces along the friction bearings47,48. As stated above, an L-shaped shaft42slidably moves, so as to restrict its own rotation by a space11harranged between an attaching member11and a plate51. An L-shaped shaft43slidably moves, so as to restrict its own rotation by a space12harranged between an attaching member12and a plate52. As shown inFIGS. 12C, 13C and 14C, the L-shaped shafts42,43slide in spaces11h,12has accompanied by a rotation of central members21,31relative to the attaching member11.

Effects of Embodiment 1

In Embodiment 1, the link members24,34are slidable with rotation relative to the attaching member11. The link members22,32are slidable with rotation relative to the attaching member12. The central members23,33and the central members21,31couple the link members24,34and the link members22,32. One end portions of the central members21,31are slidable relative to the link members24,34with rotation, and their other end portion are slidable relative to the link members22,32with rotation. In this manner, the centers of relative rotation for the adjacent link members can take positions on the inner surfaces of the link members. In the meantime, though a bending surface formed on the inner surface of the opening and closing device has a cylindrical shape from a viewpoint of technical concept, it has actually a prism shape. The envelop surfaces of a plurality of link members are actually not cylindrical surfaces, but elliptically cylindrical or substantially cylindrical surfaces. The centers of rotation for the adjacent link members are actually slightly away from the inner surfaces of the link members.

In Embodiment 1, friction generating portions40couple an attaching member11and the central members21,31, and apply a resistance force against a rotation of the central members21,31relative to the attaching member11. The friction generating portions40couple an attaching member12and the central members21,31, and apply a resistance force against a rotation of the central members21,31relative to the attaching member12. In this manner, the opening and closing device10can maintain the opening angle by the resistance force. Furthermore, to resist against a rotation of one link member and the one next to the next, the adjacent link members can be smoothly rotated, so that the entire structure formed by coupled link members can smoothly form and release from a bending. Still further, the opening and closing device10exhibits no disadvantage due to shape-memory alloy as is used in the reinforced beam made of shape-memory alloy as disclosed in JP Laid-Open Patent Application No. 2014-161009. Since the bent state in the bellows structure is not maintained by the plastic deformation of the reinforced beam, the backlash of shape-memory alloy is not an obstacle to setting the opening angle of the first casing101and the second casing102. Still further, the reinforced beam made of shape-memory alloy is not plastically deformed at every opening and closing, so there is no limitation to the number of repetitions. Still further, no shape-memory alloy is used here, so material cost for the opening and closing device10is reduced.

In Embodiment 1, the end portions41a,49aof the U-shaped shafts41,49are provided on the central members21,31so as to control a rotation relative to the central members21,31. Each of the friction bearings47has one end portion47battached to an attaching member11, and other end portions47c,47dfitted onto the U-shaped shafts41,49to apply friction force being a resistance force. In Embodiment 1, the end portions41a,49aof the U-shaped shafts41,49are provided on the central members21,31so as to control a rotation relative to the central members21,31. Each of the friction bearings48has one end portion48battached to an attaching member12, and other end portions48c,48dfitted onto the U-shaped shafts41,49to apply friction force being a resistance force. The end portions42a,45aof the L-shaped shafts42,45being examples of fifth friction members are provided on the attaching member11so as to restrict a rotation relative to the attaching member11, and fitted into the end portion47bof the friction bearing47to apply a friction force being a resistance force. The end portions43a,46aof the L-shaped shafts43,46being examples of fifth friction members are provided on the attaching member12so as to restrict a rotation relative to the attaching member12, and fitted into the end portion48bof the friction bearing48to apply a friction force being a resistance force. In this manner, it is possible to use simple and small-sized components such as U-shaped shafts, L-shaped shafts and friction bearings to structure friction generating portions40.

In Embodiment 1, the end portions42a,45aof the L-shaped shafts42,45slide along the attaching member11as accompanied by a rotation of central members21,31relative to the attaching member11. The end portions43a,46aof the L-shaped shafts43,46slide along the attaching member12as accompanied by a rotation of central members21,31relative to the attaching member12. In this manner, the L-shaped shafts42,43,45,46do not slide as accompanied by opening and closing of the opening and closing device10to prevent the opening and closing device10from opening and closing.

In Embodiment 1, the end portions41a,49aof the U-shaped shafts41,49and the end portions41b,49bof the U-shaped shafts41,49are respectively composed of the U-shaped shafts41,49being single pieces. The end portions41a,49aof the U-shaped shafts41,49and the end portions41b,49bof the U-shaped shafts41,49are respectively composed of parts in parallel facing each other of the metal wire bent in U shape. In this manner, the U-shaped shafts41,49are fixed to the central members21,31to restrict a rotation of cross sections of the U-shaped shafts41,49and to generate a friction with the friction bearings47,48.

In Embodiment 1, the friction bearings47,48are composed of elastic plate materials, wherein their respective cross sections are bent so as to pinch cross sections of the metal wire. In this manner, the structure of the friction generating portions40is simplified, so that it is possible to form them with a reduced number of parts. In Embodiment 1, in the friction generating portions40, the first friction generating means and the second friction generating means are integrally coupled on a central block15, by the U-shaped shafts41,49. In this manner, the total number of parts is reduced for the first friction generating means and the second friction generating means.

In Embodiment 1, a plurality of sets of the friction generating portions40are disposed between a pair of the coupling portions20,30, wherein each of the coupling portions is composed of an attaching member11, link members24,34, an attaching member12, link members22,32and a central block15. In this manner, differences in resistance between the first friction generating means and the second friction generating means are reduced by measuring a resistance each of a plurality of sets of the friction generating portions and then combining these.

In Embodiment 1, a combination an arc groove formed on one of adjacent link members and an arc convex portion formed on the other brings about a structure sliding with rotation. However, the structure sliding with rotation is not limited to a combination the arc groove and the arc convex portion. Even if the arc convex portions are replaced with a pair of pins disposed at positions corresponding to the end portions in a circumferential direction, it is possible to realize a relative movement between adjacent link members as in Embodiment 1. An arc-shaped rail can be provided on one of the adjacent link members, and two pairs of rollers on the other of the adjacent link members. In the meantime, a sliding movement with rotation is equivalent to a rotating movement with sliding.

In Embodiment 1, a resistance force is applied to a relative rotation of two link members over another one located between both by an interference-fit of a pin having a circular cross section and a circular hole. However, a structure for applying a resistance force to a relative rotation of two link members over another one located between both is not limited to an interference-fit of a pin having a circular cross section and a circular hole. Friction bearings equal to the ones in Embodiment 1 can be also disposed on a central block15and attaching members11,12, and these three friction bearings can be coupled to each other using U-shaped shafts as in Embodiment 1. Here, it is preferable to provide the friction bearings disposed on the attaching members11,12such that they are movable along the attaching members11,12.

In Embodiment 1, friction generating portions are formed of L-shaped shafts and U-shaped shafts, both made of a metal wire, as well as of friction bearings made of an elastic metal plate with its ends being curled. However, combinations of components and shapes on the insertion side and on the side undergoing an insertion are not limited to that in Embodiment 1. Various combinations of materials which can generate a stable frictional relative movement between the insertion side and the side undergoing the insertion can be selected. It is also possible that a friction bearing on the insertion side is made up of highly rigid material and the one on the side undergoing an insertion of a material with an elastically shrinkable diameter.

In Embodiment 1, friction generating portions are assembled independently of a plurality of link members sliding with rotation to be integrally detachable from a plurality of the link members. However, a plurality of the link members and the friction generating portions can be also assembled with parts at least partially in common. For example, circular holes for interference-fit can be also provided, wherein shaft portions of U-shaped and L-shaped shafts are inserted into the circular holes.

In Embodiment 1, a plurality of friction generating portions40are all identical. However, it is also possible that a plurality of friction generating portions40have resistance forces different in quantity or quality. As per quantity of resistance forces, it is conceivable that a plurality of types of friction generating portions with different sizes of their friction resistances are arranged, and two each of the plurality of types of friction generating portions are combined, such that respective sizes of their friction resistances lie within a predetermined range. As per quality of resistance forces, it is conceivable that friction generating portions are provided such that resistance forces generated with regard to rotation fluctuate depending on an opening angle, and they take the maximum at a predetermined opening angle, and the minimum at some intermediate angle.

For example, an opening and closing device of a laptop PC for coupling a display casing and a main body casing comprises friction generating portions (also referred to as drawing mechanism) with resistance forces generated with regard to rotation being minimum at opening angles of 0 degree and 90 degrees. Concretely, pins or cams having regular polygon cross sections are arranged instead of circular cross sections, and holes of resin material having regular polygon cross sections instead of friction bearings with metal plate end portions being curled. Then, fluctuations in rotation resistance when the pins having regular polygon cross sections rotate in the holes having regular polygon cross sections are utilized. The resistance to relative rotation takes the minimum at angles at which vertices of regular polygon cross sections meet, and it takes the maximum between these angles. Or otherwise, a detent mechanism can be also used, wherein pins or cams having flat cross sections are sandwiched by elastic members having U-shaped cross sections to reduce a resistance to rotation with a phase difference of 180 degrees.

Further Embodiments

An opening and closing device according to the invention is not limited to specific structure and applications as described in foregoing embodiments. It can be also realized in other embodiments, in which a part or the whole of structure in foregoing embodiments is replaced by an equivalent structure. In foregoing embodiments, reference is made to an opening and closing device for a terminal device with an organic EL panel. However, an opening and closing device in foregoing embodiments can be also used in a terminal device with an LED panel. Instead of twofold, a threefold, fourfold, multifold bellows structure or so on can be also used. Terminal devices include a foldable TV set. The invention can be realized in an electrical device other than terminal device in which a flexible planar device not for displaying an image, e.g. touch panel, keyboard, or so on is folded and housed inside. It can be used in various equipment and containers, wherein a first casing and a second casing are coupled to each other by a plurality of the link members to form bent envelop surfaces on the inside.

Since the invention is constructed as described in the foregoing, it is suitably used both as an opening and closing device for a two-fold type terminal device, e.g. cellular phone, smartphone, notebook PC, tablet PC, game machine, display, sign board and so on, wherein a flexible display panel is arranged to cross a first casing and a second casing, and as a terminal device using such an opening and closing device.