Eyewear

This eyewear is provided with: a lens which has an electric element, an electrode of the electric element being disposed at an edge of the lens; a frame which has a control unit for controlling the electric element, and which holds the lens; a conductive wire which has a long conductor surface that extends along and facing such edge, and which is connected to the control unit; and a conductive piece which extends along and facing such edge and which comes into contact with the electrode and the conductor surface.

TECHNICAL FIELD

The present invention relates to eyewear.

BACKGROUND ART

Eyewear having a lens including an electric element, such as a liquid crystal lens with a changeable refractive index, driven by application of a driving voltage is under development (see, for example, PTL 1).

A lens used for such eyewear is, for example, cut out from lens blank400as illustrated inFIG. 5. Lens blank400includes liquid crystal lens411and a pair of electrodes412at predetermined positions.

It is necessary to dispose liquid crystal lens411in front of the user's pupil. Accordingly, cutting line413is determined according to the positions of the user's pupils (distance between the pupils), the frame shape of eyewear and the like so that liquid crystal lens411is located at a desired position in the cut out lens. After cutting line413is determined, a lens is cut out from lens blank400along cutting line413.

CITATION LIST

Patent Literature

Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2015-522842

SUMMARY OF INVENTION

Technical Problem

Depending on the position where a lens is cut out from a lens blank, the location of an electrode of a liquid crystal lens at the edge portion of the lens varies. For example, when the lens is cut out from lens blank400along second cutting line414in place of cutting line413, the locations of electrodes412in the cut out lens are changed. When the location of an electrode of a liquid crystal lens changes, it is necessary to adjust the position of the electrode on the control section side in order to ensure conduction to the control section that controls the liquid crystal lens. That is, it is necessary to change the design of a conductive path between the liquid crystal lens and the control section.

However, since the location of an electrode of a liquid crystal lens at the edge portion of a lens changes depending on the way the lens is cut out from lens blank400, the location varies greatly. Accordingly, it is inefficient to change the design of a conductive path between a liquid crystal lens and a control section according to the location of an electrode of the liquid crystal lens. Such a problem persists in the case where the lens includes an electric element other than a liquid crystal lens.

The present invention is made in view of such a situation, and an object thereof is to provide eyewear in which conduction between an electric element and a control section is ensured even when the location of an electrode of the electric element varies.

Solution to Problem

Eyewear according to the present invention includes: a lens including an electric element and an edge portion provided with an electrode of the electric element; a frame which includes a control section for controlling the electric element, and which holds the lens; a conductive wire which includes an elongated conductor surface that extends along and faces the edge portion, and which is connected to the control section; and a conductive piece which extends along and facing the edge portion, and which is in contact with the electrode and the conductor surface.

Advantageous Effects of Invention

The present invention is capable of providing eyewear in which conduction between an electric element and a control section is ensured even when the location of an electrode of the electric element varies.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, electronic glasses having a transparent lens for vision correction that has a liquid crystal lens (electroactive region) whose optical characteristics can be changed by electrical control will be described as a representative example of eyewear according to the present invention.

FIG. 1is a perspective view illustrating an example of the configuration of electronic glasses100according to the present embodiment. Electronic glasses100have a pair of lenses110and frame120. Frame120includes front130and a pair of temples140. The following description will be made with the side on which front130is located referred to as the front side of electronic glasses100and lenses110, and the side on which temples140are located referred to as the rear side of electronic glasses100and lenses110.FIG. 1illustrates the periphery of temple140for a right side and front130as a partially exploded view.

The pair of lenses110are formed so as to be substantially symmetric when electronic glasses100are viewed from the front, and lenses110have the same components. In addition, the peripheral structures of lenses110are the same. As the details will be described below, lens110for a right eye (first lens) and the peripheral structure thereof in electronic glasses100will be described in the following description, and the description for lens110for a left eye (second lens) and the peripheral structure thereof will be omitted.

Lens110includes liquid crystal lens111and a pair of electrodes112. A transparent electrode such as ITO is used as electrode112.

FIG. 2is a plan view of lens110for a right eye. Lens110has a multilayer structure in which a plurality of layers are stacked in the thickness direction of lens110, and includes a pair of conductive layers (not shown) holding a liquid crystal layer (not shown) therebetween from the front and rear at a portion that includes liquid crystal lens111. The pair of conductive layers are connected to electrodes112, respectively. Applying a voltage between the pair of the conductive layers via electrodes112activates the liquid crystal layer, thereby changing the refractive index of liquid crystal lens111.

Lens110is formed by being cut out from a lens blank so as to have a shape that matches the shape of rim131(FIG. 1) described below.

End portions of the pair of electrodes112are exposed and disposed at edge portion113surrounding the outer periphery of lens110. Electrodes112are disposed apart from each other in the thickness direction of lens110by the thickness of the liquid crystal layer. The locations of electrodes112and the distance therebetween change depending on the lens blank from which lens110is cut out and the cutout position on the lens blank. The distance between electrodes112is generally 10 to 21 mm in the direction along edge portion113.

By referring toFIG. 1again, frame120and the periphery thereof will be described. Front130constituting frame120includes a pair of rims131that respectively hold a pair of lenses110, and bridge132that connects the pair of rims131to each other. Front130has a pair of nose pads133that can contact a wearer's nose.

The material of front130is not particularly limited, and is appropriately selected from, for example, metals such as titanium, aluminum and stainless steel, resins such as polyamide, acetate, celluloid, polyetherimide and polyurethane, and carbon.

The pair of temples140constituting a part of frame120are formed so as to have outer shapes that are substantially symmetrical. Temple140for a right side includes built-in control section150and power source160. Hereinafter, temple140for a right side will be described, and the description of temple140for a left side will be omitted. Temple140for a left side may include built-in control section150and power source160.

Temple140is rotatably attached at the front end thereof to front130via a hinge.

Temple140includes housing141that houses detection section142, control section150, power source160, and a part of flexible substrate (also referred to as a flexible printed wiring board or FPC)200.

Housing141defines the outer shape of temple140. Housing141extends along one direction. The shape of housing141is not particularly limited. For a wearer to easily recognize the position of detection section142by merely touching by hand, housing141may be such that a part thereof has a shape different from the other part thereof. In the present embodiment, the shape of one part of housing141is different from that of the other parts of housing141. A projected line is formed on the right side surface of housing141(the outer surface of electronic glasses100). A position corresponding to detection section142is formed to have a planar shape on the right side surface of housing141. This configuration enables a wearer to easily recognize the position where detection section142is disposed.

The material of housing141is not particularly limited, and is appropriately selected from, for example, metals such as titanium, aluminum and stainless steel, resins such as polyamide, acetate, celluloid, polyetherimide and polyurethane, and carbon. For a wearer to easily recognize the position of detection section142, housing141may be such that a part thereof is formed from a material different from the other part thereof. When metal is used as the material for housing141, housing141are insulated from detection section142.

Detection section142includes, for example, a capacitive detection pad. Any detection pad known in the art to be used as a touch sensor can be used as the detection pad. When an object (such as a wearer's finger) touches a position of the housing141corresponding to detection section142, detection section142detects a change in capacitance caused by the contact.

Control section150is electrically connected to the detection pad of detection section142and liquid crystal lens111. Control section150controls the optical characteristics of liquid crystal lens111by controlling a voltage applied to below described liquid crystal lens111. For example, when detection section142detects contact of an object, control section150applies a voltage to the pair of liquid crystal lenses111or stops the application of the voltage, thereby switching the refractive index of liquid crystal lenses111. Control section150includes a control circuit configured to control, for example, the driving of the detection pad, the detecting of capacitance change in the detection pad, and the applying of a voltage to liquid crystal lens111. Control section150is mounted in detection section142, for example, in a state such that control section150is connected to the detection pad for receiving a detection result regarding a change in capacitance in the detection pad.

Power source160supplies electric power to detection section142, control section150, and liquid crystal lens111. Power source160may be a rechargeable battery pack detachably held at the other end (rear end) of temple140. Examples of power source160include a nickel-metal hydride rechargeable battery.

Flexible substrate200and conductive piece(s)300are disposed between front130and lens110. Flexible substrate200and conductive pieces300constitute conductive paths that electrically connect the pair of electrodes112and control section150.

FIG. 3Ais a bottom view of flexible substrate200,FIG. 3Bis an enlarged view of a portion indicated by dotted line B inFIG. 3A, andFIG. 3Cis a cross-sectional view taken along line C-C ofFIG. 3B.FIGS. 3B and 3Calso illustrates conductive piece(s)300.

Flexible substrate200has a multilayer structure in which a pair of insulating layers201hold conductive wire layer202therebetween. Flexible substrate200is connected to control section150via connection portion210provided at one end of flexible substrate200. Flexible substrate200is disposed inside temple140, between front130and lens110, and inside, under or behind bridge132so as to extend along temple140and front130.

The total length of flexible substrate200is substantially equal to the sum of the distance between the left and right ends of front130and the distance between front130and control section150. The width of flexible substrate200is smaller than the width (thickness in the front-rear direction) of front130throughout the entire flexible substrate200. That is, flexible substrate200has an elongated shape as a whole. The width of flexible substrate200is, for example, 1 mm or more and 5 mm or less.

Insulating layer201is formed of a flexible insulating body such as a synthetic resin.

Conductive wire layer202is provided with first conductive wire220and second conductive wire230which are each formed of a conducting body such as copper and which extend substantially parallel to each other. First conductive wire220and second conductive wire230are insulated from each other. First conductive wire220constitutes a conductive path between control section150and a conductive layer (i.e., liquid crystal lens111) which is one of the pair of conductive layers constituting a part of liquid crystal lens111and which is disposed on the rear side (user side). Second conductive wire230constitutes a conductive path between control section150and a conductive layer (i.e., liquid crystal lens111) which is one of the pair of conductive layers constituting a part of in liquid crystal lens111and which is disposed on the front side. The number of conductive wires disposed in conductive layers202is in accordance with the number of electrodes112disposed at edge portion113of lens110.

First conductive wire220has, in parts thereof, first contact forming portion221and second contact forming portion222. In addition, second conductive wire230has, in parts thereof, third contact forming portion231and fourth contact forming portion232. Each of these contact forming portions221to232forms an electrical contact by contacting conductive piece300.

First contact forming portion221and third contact forming portion231are connected to the pair of electrodes112disposed at edge portion113of lens110for a right eye via conductive pieces300, respectively. In addition, second contact forming portion222and fourth contact forming portion232are connected to the pair of electrodes112disposed at edge portion113of lens110for a left eye via conductive pieces300, respectively.

First contact forming portion221, second contact forming portion222, third contact forming portion231and fourth contact forming portion232respectively include first elongated conductor surface221S, second elongated conductor surface222S, third elongated conductor surface231S and fourth elongated conductor surface232S. These elongated conductor surfaces221S to232S all extend along and face edge portion113of lens110. These elongated conductor surfaces221S to232S all extend with a constant width along edge portion113over a predetermined range. In addition, these elongated conductor surfaces221S to232S spread over the entire range extending along edge portion113. In other words, within the range in which each of elongated conductor surfaces221S to232S extends along edge portion113, there is no missing site in each of elongated conductor surfaces221S to232S caused by, for example, being provided with a hole or covered with an insulating body.

Flexible substrate200configured as described above functions as one cable.

Conductive piece300is formed of a material having flexibility and conductivity, such as conductive rubber. Herein, having flexibility means that Young's modulus is small compared to that of lens110and front130. One conductive piece300is disposed on each of first elongated conductor surface221S, second elongated conductor surface222S, third elongated conductor surface231S and fourth elongated conductor surface232S. Conductive piece300is attached to each of long conductor surfaces221S to232S with, for example, a double-sided tape. During the procedure, the double-sided tape is naturally dimensioned so as not to prevent conduction between conductive piece300and each of elongated conductor surfaces221S to232S.

In electronic glasses100configured as described above, flexible substrate200and conductive piece300are disposed between front130and edge portion113of lens110and sequentially from the front130side. At this time, conductive piece300is disposed between lens110on the lower side, and front130and flexible substrate200on the upper side in a state of being slightly compressed from the top and bottom. Accordingly, conductive piece300is in close contact with electrode112and each of elongated conductor surfaces221S to232S, thereby ensuring reliable electrical conduction. In addition, since Young's modulus of conductive piece300is smaller than that of lens110(that is, conductive piece300is flexible), distortion of lens110from excessive stress is prevented.

First elongated conductor surface221S to fourth elongated conductor surface232S which extend in the direction along edge portion113of lens110are disposed at positions that face electrodes112located at edge portion113. Accordingly, even when the position where lens110is cut out from a lens blank is changed, and thus the position of each electrode112at edge portion113of lens110is changed, each of elongated conductor surfaces221S to232S can reliably face each electrode112. Therefore, electrodes112can be electrically connected to contact forming portions221to232via conductive pieces300respectively, without changing the design of flexible substrate200and members disposed in the periphery thereof in accordance with the position where lens110is cut out from a lens blank.

In addition, each of elongated conductor surfaces221S to232S spreads over the entire range where each of elongated conductor surfaces221S to232S extends along edge portion113. In other words, within the range extending along edge portion113, there is no missing site in each of elongated conductor surfaces221S to232S caused by, for example, being provided with a hole or covered with an insulating body. Accordingly, each of elongated conductor surfaces221S to232S can achieve conductive contact with conductive piece300more reliably and in a wider area. Therefore, more reliable conduction between electrodes112and respective contact forming portions221to232via conductive piece300is ensured and power loss when liquid crystal lens111drives can be minimized.

In the following, the dimensions of the members disposed in the periphery of flexible substrate200and the relationship thereof will be described.FIG. 4is a model diagram of relative positions and dimensions of electrodes112of liquid crystal lens111, conductive pieces300and elongated conductor surfaces221S and231S in the periphery of lens110for a right eye. The direction indicated by the arrow inFIG. 4is the direction in which edge portion113of lens110extends. Although the state in the periphery of lens110for a left eye is not shown inFIG. 4, the following description naturally applies to the periphery of lens110for a left eye110as well.

The length “L1” of electrode112in the direction along edge portion113of lens110is generally 0.5 mm or more and 3 mm or less, and preferably 1.5 mm or more and 2.5 mm or less.

In the direction along edge portion113, the length “L2” of conductive piece300is shorter than the length “L3” of each of elongated conductor surfaces221S and231S. The above configuration can prevent separation between conductive piece300and electrode112caused by conductive piece300being curved along the inner surface of front130together with flexible substrate200and being lifted from edge portion113when flexible substrate200, conductive pieces300and lens110are assembled in front130. Further, the contact pressure between conductive piece300and electrode112can be sufficiently increased, and conduction therebetween can be reliably ensured. For obtaining the above effects, in the direction along edge portion113of lens110, the length “L2” of conductive piece300is preferably 1 to 4 times, more preferably 1 to 2.5 times, and particularly preferably 2.5 times the length “L1” of electrode112. That is, it is particularly preferable that the relationship of the following formula 1 is satisfied:
L2=2.5L1(Formula 1).

As described above, in the direction along edge portion113, the length “L2” of conductive piece300is equal to or longer than the length “L1” of electrode112. Accordingly, even when some error occurs in the assembly position of flexible substrate200and/or conductive piece300between lens110and front130, conductive piece300can reliably contact electrode112and each of elongated conductor surfaces221S and231S.

Specifically, the length “L2” of conductive piece300in the direction along edge portion113of lens110is preferably 0.5 mm or more and 7.5 mm or less, and more preferably 1.5 mm or more and 6.25 mm or less.

In addition, as shown by a broken line inFIG. 4, when lens110is cut out from a lens blank, the position of electrode112at edge portion113of lens110may vary depends on the positions of user's pupils (width between the pupils) and the shape of frame120. This variation width “L4” in the direction along edge portion113is generally 5 mm or more and 11 mm or less, preferably 9 mm or more and 11 mm or less. Therefore, the length “L3” of each of elongated conductor surfaces221S and231S in the direction along edge portion113is preferably set to a dimension that satisfies the following formula 2:
L3=L2+L4(Formula 2).

Satisfying such a relationship can more reliably bring conductive piece300into contact with each of elongated conductor surfaces221S and231S regardless of the variation in the position of electrode112.

Specifically, the length L3of each of elongated conductor surfaces221S and231S in the direction along edge portion113is preferably 5.5 mm or more and 18.5 mm or less, and more preferably 10.5 mm or more and 17.25 mm or less.

The length “L3” of each of elongated conductor surfaces221S and231S is not necessarily be an exact sum of the length “L2” of conductive piece300and the variation width “L4” and some increase or decrease is naturally acceptable.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, the eyewear according to the present invention includes glasses (including electronic glasses and sunglasses) and goggles all having an auxiliary mechanism for improving a user's visual acuity, such as a visual acuity correction lens. In addition, the eyewear according to the present invention includes various devices (for example, a glasses-type wearable terminal and a head-mounted display) having a mechanism for presenting information to the user's field of view or eyes.

The eyewear according to the present invention may be in any configuration as long as it can hold an auxiliary mechanism for improving visual acuity or field of view, a mechanism for presenting information, or the like in front of or around a wearer's eyes. The eyewear according to the present invention is not limited to a glasses type that can be worn on both ears, but may be a type that is worn on a head, one ear or the like. In addition, the eyewear according to the present invention is not limited to eyewear for both eyes, but may be eyewear for one eye.

In the eyewear according to the present invention, each lens may include a plurality of electric elements. For example, each lens may include a liquid crystal lens for electrochromic (light control) and a liquid crystal lens for presbyopia correction. In addition, each lens may include a plurality of liquid crystal lenses for vision correction so that the lens can correspond to multiple focal points. In these cases, four electrodes are disposed at the edge portion of each lens.

The number of electrodes included in one electric element is not limited to two, and may naturally be one or three or more.

This application is entitled to and claims the benefit of Japanese Patent Application No. 2017-178965 filed on Sep. 19, 2017, the disclosure of which including the specification, drawings and abstract is incorporated herein by reference in its entirety.

INDUSTRIAL APPLICABILITY

The present invention is suitably used as eyewear provided with a lens including an electric element.

REFERENCE SIGNS LIST