Transparent antenna and transparent antenna-equipped display device

Included is an antenna wire 21, formed by a reticulated metal film in a shape of a ring, which generates a magnetic field on a center side thereof. The antenna wire 21 has a first extension part 23 extending along a direction of extension of the antenna wire 21 and a second extension part 24 extending along a direction intersecting with the direction of extension. The antenna wire 21 is configured such that a per unit length area of the first extension part 23 is larger than a per unit length area of the second extension part 24.

TECHNICAL FIELD

The present invention relates to a transparent antenna and a transparent antenna-equipped display device.

BACKGROUND ART

A known example of a transparent antenna that is attached to a screen of a display to perform communication with an external device or the like is described in PTL 1 listed below. PTL 1 describes a transparent antenna including: a transparent substrate; and an antenna pattern formed on at least one surface of the transparent substrate, wherein the antenna pattern is formed by a conductor mesh layer obtained by forming an opaque conductor layer in a mesh pattern, and the mesh pattern is constituted by a large number of boundary segments defining a large number of opening regions and includes a region comprising patterns in which the average N of the numbers of boundary segments that extend from one branch point is 3.0≤N<4.0 and there is no direction in which the opening regions have repetition frequency.

CITATION LIST

Patent Literature

Technical Problem

PTL 1 states that the antenna pattern of the transparent antenna is formed by the conductor mesh layer. Note here that while increased light transmittance of the transparent antenna can be achieved simply by expanding the opening regions of the conductor mesh layer, doing so undesirably invites an increase in wiring resistance and, by extension, a decrease in antenna performance. On the other hand, while improved antenna performance of the transparent antenna can be achieved simply by widening the boundary segments defining the opening regions of the conductor mesh layer, doing so undesirably invites a reduction in size of the opening regions and, by extension, a decrease in light transmittance. Thus, the transparent antenna including the conductor mesh layer has suffered from a trade-off between light transmittance and wiring resistance.

SUMMARY OF INVENTION

The present invention is one achieved in view of such circumstances and has as an object to achieve a reduction in wiring resistance while achieving sufficient light transmittance.

Solution to Problem

A first transparent antenna of the present invention includes an antenna wire, formed by a reticulated metal film in a shape of a ring, which generates a magnetic field on a center side thereof. The antenna wire has a first extension part extending along a direction of extension of the antenna wire and a second extension part extending along a direction intersecting with the direction of extension. The antenna wire is configured such that a per unit length area of the first extension part is larger than a per unit length area of the second extension part.

In this way, the flow of an electric current through the ring-shaped antenna wire causes a magnetic field to be generated on the center side of the antenna wire by an electromagnetic induction effect. The antenna wire is formed by the reticulated metal film, which has reticulations through which light is transmitted, whereby the translucency of the transparent antenna is secured. The wiring resistance of the antenna wire tends to become lower as the opening area of the reticulations in the metal film becomes smaller and the area of the metal film becomes larger, and tends to become higher as the opening area of the reticulations in the metal film becomes larger and the area of the metal film becomes smaller. Note here that the influence on the wiring resistance of the per unit length area of the first extension part, of the antenna wire, which extends along the direction of extension of the antenna wire, is relatively greater than the influence on the wiring resistance of the per unit length area of the second extension part, of the antenna wire, which extends along a direction intersecting with the direction of extension.

Moreover, since the antenna wire is configured such that the per unit length area of the first extension part, which extends along the direction of extension of the antenna wire, is larger than the per unit length area of the second extension part, which extends along a direction intersecting with the direction of extension, it is possible to efficiently lower the wiring resistance while sufficiently securing the opening area of the reticulations. This makes it possible to achieve a reduction in wiring resistance while achieving sufficient light transmittance.

It is preferable that embodiments of the first transparent antenna of the present invention be configured as follows:(1) The antenna wire has a plurality of reticulations and a plurality of demarcation parts demarcating the reticulations, the demarcation parts being each constituted by a first demarcation part extending along the direction of extension and a second demarcation part extending along a direction intersecting with the direction of extension, the first extension part comprises a plurality of the first demarcation parts, and the second extension part comprises a plurality of the second demarcation parts. In this way, the per unit length area of the first extension part comprising the plurality of first demarcation parts is larger than the per unit length area of the second extension part comprising the plurality of second demarcation parts. This makes it possible to efficiently lower the wiring resistance while sufficiently securing the opening area of the reticulations. This in turn makes it possible to achieve a reduction in wiring resistance while achieving sufficient light transmittance.(2) The first demarcation part has a line width that is greater than a line width of the second demarcation part. In this way, by making the line width of the first demarcation part wider than the line width of the second demarcation part, the per unit length area of the first extension part comprising a plurality of the first demarcation parts can be made larger than the per unit length area of the second extension part comprising a plurality of the second demarcation parts.(3) A spacing between adjacent ones of the second demarcation parts is wider than a spacing between adjacent ones of the first demarcation parts. In this way, by making the spacing between adjacent second demarcation parts wider than the spacing between adjacent first demarcation parts, the opening area of the reticulations can be expanded. This makes it possible to suitably achieve a reduction in wiring resistance by making the line width of the first demarcation part relatively wider and to, by making the spacing between adjacent second demarcation parts relatively wider, ensure the opening area of the reticulation as usual while maintaining the wiring resistance.(4) A spacing between adjacent ones of the first demarcation parts is narrower than a spacing between adjacent ones of the second demarcation parts. In this way, by making the spacing between adjacent first demarcation parts narrower than the spacing between adjacent second demarcation parts, the number of first demarcation parts provided is made larger than the number of second demarcation parts provided. This allows the per unit length area of the first extension part comprising the plurality of first demarcation parts to be larger than the per unit length area of the second extension part comprising the plurality of second demarcation parts. Moreover, by appropriately adjusting the spacing between adjacent second demarcation parts, it is made possible to ensure the opening area of the reticulations as usual while maintaining the wiring resistance.(5) The antenna wire has a planar shape forming a quadrangular ring and has a pair of first side parts extending parallel to a first direction and a pair of second side parts extending parallel to a second direction orthogonal to the first direction, the first side parts are each configured such that the first demarcation part extends along the first direction and the second demarcation part extends along the second direction, and the second side parts are each configured such that the first demarcation part extends along the second direction and the second demarcation part extends along the first direction. In this way, in each of the first side parts, of the antenna wire having a planar shape forming a quadrangular ring, which extend parallel to the first direction, the per unit length area of the first extension part comprising a plurality of the first demarcation parts extending along the first direction is larger than the per unit length area of the second extension part comprising a plurality of the second demarcation parts extending along the second direction orthogonal to the first direction. On the other hand, in each of the second side parts, of the antenna wire, which extend parallel to the second direction, the per unit length area of the first extension part comprising a plurality of the first demarcation parts extending along the second direction is larger than the per unit length area of the second extension part comprising a plurality of the second demarcation parts extending along the first direction. This makes it possible to achieve a reduction in wiring resistance while achieving sufficient light transmittance.(6) The antenna wire has a planar shape forming a quadrangular ring and has a pair of first side parts extending parallel to a first direction and a pair of second side parts extending parallel to a second direction orthogonal to the first direction, the first side parts are each configured such that the first demarcation part extends along a direction inclined with respect to the first and second directions and the second demarcation part extends along the second direction, and the second side parts are each configured such that the first demarcation part extends along a direction inclined with respect to the first and second directions and the second demarcation part extends along the first direction. In this way, in each of the first side parts, of the antenna wire having a planar shape forming a quadrangular ring, which extend parallel to the first direction, the per unit length area of the first extension part comprising a plurality of the first demarcation parts extending along a direction inclined with respect to the first and second directions is larger than the per unit length area of the second extension part comprising a plurality of the second demarcation parts extending along the second direction orthogonal to the first direction. On the other hand, in each of the second side parts, of the antenna wire, which extend parallel to the second direction, the per unit length area of the first extension part comprising a plurality of the first demarcation parts extending along a direction inclined with respect to the first and second directions is larger than the per unit length area of the second extension part comprising a plurality of the second demarcation parts extending along the first direction. This makes it possible to achieve a reduction in wiring resistance while achieving sufficient light transmittance.(7) The antenna wire has a planar shape forming a quadrangular ring and has a pair of first side parts extending parallel to a first direction and a pair of second side parts extending parallel to a second direction orthogonal to the first direction, the first side parts are each configured such that the first demarcation part extends in such a form as to intersect with the first direction and the second direction and has a planar shape forming a curve and the second demarcation part extends along the second direction, and the second side parts are each configured such that the first demarcation part extends in such a form as to intersect with the first direction and the second direction and has a planar shape forming a curve and the second demarcation part extends along the first direction. In this way, in each of the first side parts, of the antenna wire having a planar shape forming a quadrangular ring, which extend parallel to the first direction, the per unit length area of the first extension part comprising a plurality of the first demarcation parts each extending in such a form as to intersect with the first direction and the second direction and having a planar shape forming a curve is larger than the per unit length area of the second extension part comprising a plurality of the second demarcation parts extending along the second direction orthogonal to the first direction. On the other hand, in each of the second side parts, of the antenna wire, which extend parallel to the second direction, the per unit length area of the first extension part comprising a plurality of the first demarcation parts extending in such a form as to intersect with the first direction and the second direction and having a planar shape forming a curve is larger than the per unit length area of the second extension part comprising a plurality of the second demarcation parts extending along the first direction. This makes it possible to achieve a reduction in wiring resistance while achieving sufficient light transmittance.(8) The antenna wire has a planar shape forming a quadrangular ring and has a pair of first side parts extending parallel to a first direction, a pair of second side parts extending parallel to a second direction orthogonal to the first direction, and corner parts connecting the first side parts and the second side parts, the first side parts and the second side parts each have the first extension part and the second extension part, the corner parts each have a corner-part first extension part extending parallel to the first direction and a corner-part second extension part extending parallel to the second direction, and the corner parts are each configured such that the corner-part first extension part and the corner-part second extension part are equal in per unit length area to each other. In this way, since the first side parts extend parallel to the first direction and the second side parts extend parallel to the second direction orthogonal to the first direction, the per unit length area of the first extension part in each of the first and second side parts is larger than the per unit length area of the second extension part in each of the first and second side parts. This makes it possible to efficiently lower the wiring resistance while sufficiently securing the opening area of the reticulations in the first side parts and the second side parts. Meanwhile, since the corner parts connect the first side parts and the second side parts, the corner-part first extension part and the corner-part second extension part are equal in per unit length area to each other. This makes it difficult for the first side parts and the second side parts to differ from each other in terms of the opening area of the reticulations and the wiring resistance.(9) The corner parts are each configured such that the per unit length area of the corner-part first extension part is smaller than the per unit length area of the first extension part constituting the first side parts and the second side parts and the per unit length area of the corner-part second extension part is larger than the per unit length area of the second extension part constituting the first side parts and the second side parts. In this way, the per unit length areas of the corner-part first and second extension parts constituting the corner part are appropriate. This makes it more difficult for the first side parts and the second side parts to differ from each other in terms of the opening area of the reticulations and the wiring resistance.(10) A lead wiring part extending in such a form as to lead from the antenna wire is further included, the lead wiring part has a first lead extension part extending along a direction of extension of the lead wiring part and a second lead extension part extending along a direction intersecting with the direction of extension of the lead wiring part, and the lead wiring part is configured such that a per unit length area of the first lead extension part is larger than a per unit length area of the second lead extension part. In this way, the flow of an electric current through the ring-shaped antenna wire due to the passage of electricity through the lead wiring part causes a magnetic field to be generated on the center side of the antenna wire by an electromagnetic induction effect. This lead wiring part is configured such that the per unit length area of the first lead extension part extending along the direction of extension of the lead wiring part is larger than the per unit length area of the second lead extension part extending along a direction intersecting with the direction of extension of the lead wiring part. This makes it possible to efficiently lower the wiring resistance while sufficiently securing the opening area of the reticulations. This in turn makes it possible to achieve a reduction in wiring resistance while achieving sufficient light transmittance.

A second transparent antenna of the present invention includes an antenna wire, formed by a reticulated metal film in a shape of a ring, which generates a magnetic field on a center side thereof. The antenna wire has a first extension part extending along a direction inclined with respect to both a direction of extension of the antenna wire and a direction orthogonal thereto and a second extension part extending along a direction inclined with respect to both the direction of extension and the direction orthogonal thereto and intersecting with the first extension part. The antenna wire is configured such that each of the first and second extension parts is inclined at a smaller angle with respect to the direction of extension than with respect to the direction orthogonal to the direction of extension.

In this way, the flow of an electric current through the ring-shaped antenna wire causes a magnetic field to be generated on the center side of the antenna wire by an electromagnetic induction effect. The antenna wire is formed by the reticulated metal film, which has reticulations through which light is transmitted, whereby the translucency of the transparent antenna is secured. The wiring resistance of the antenna wire tends to become lower as the opening area of the reticulations in the metal film becomes smaller and the area of the metal film becomes larger, and tends to become higher as the opening area of the reticulations in the metal film becomes larger and the area of the metal film becomes smaller. Note here that, in the first extension part extending along a direction inclined with respect to both the direction of extension of the antenna wire and a direction orthogonal thereto and the second extension part extending along a direction inclined with respect to both the direction of extension of the antenna wire and the direction orthogonal thereto and intersecting with the direction of extension of the first extension part, the path length in the direction of extension of the antenna wire tends to become longer and the path length in the direction orthogonal to the direction of extension of the antenna wire tends to become shorter as the angle of inclination with respect to the direction of extension of the antenna wire becomes larger and the angle of inclination with respect to the direction orthogonal to the direction of extension of the antenna wire becomes smaller, and the path length in the direction of extension of the antenna wire tends to become shorter and the path length in the direction orthogonal to the direction of extension of the antenna wire tends to become longer as the angle of inclination with respect to the direction of extension of the antenna wire becomes smaller and the angle of inclination with respect to the direction orthogonal to the direction of extension of the antenna wire becomes larger.

Moreover, since the antenna wire is configured such that each of the first and second extension parts is inclined at a smaller angle with respect to the direction of extension of the antenna wire than with respect to the direction orthogonal to the direction of extension of the antenna wire, the path length in the direction of extension of the antenna wire becomes shorter. This makes it possible to efficiently lower the wiring resistance while sufficiently securing the opening area of the reticulations. This in turn makes it possible to achieve a reduction in wiring resistance while achieving sufficient light transmittance.

Next, in order to solve the problems, a transparent antenna-equipped display device of the present invention includes: a transparent antenna described above; a transparent antenna substrate provided with the transparent antenna; and a display panel, stacked on the transparent antenna substrate, which has a display region that is capable of displaying an image and a non-display region surrounding the display region. The transparent antenna is placed in a position overlapping the display region.

In this way, the use of the transparent antenna placed in a position overlapping the display region of the display panel makes it possible to perform communication, for example, with an external device or the like. This makes it possible to perform an operation such as bringing the external device closer to the transparent antenna in accordance with an image displayed on the display region, thus offering great convenience. Moreover, the antenna performance of the transparent antenna is so high that communication with the external device or the like can be satisfactorily performed.

It is preferable that the transparent antenna-equipped display device of the present invention be configured as follows:(1) The display panel has a large number of pixels arranged in a matrix in a plane of a display surface of the display panel, the transparent antenna has a large number of reticulations arranged in a matrix, and a direction of arrangement of the reticulations is inclined with respect to a direction of arrangement of the pixels. In this way, the inclination of the direction of arrangement of the reticulations of the transparent antenna with respect to the direction of arrangement of the pixels in the display panel reduces the appearance of interference fringes called moiré, thereby bringing about improvement in display quality.

Advantageous Effects of Invention

The present invention makes it possible to achieve a reduction in wiring resistance while achieving sufficient light transmittance.

DESCRIPTION OF EMBODIMENTS

Embodiment 1 of the present invention is described with reference toFIGS. 1 to 10. The present embodiments illustrates a transparent antenna-equipped liquid crystal display device10that enables communication with an external device (not illustrated) via a transparent antenna17. It should be noted that part of each of the drawings shows an X axis, a Y axis, and a Z axis and each of the drawings is drawn to indicate directions along these axes, respectively.

First, a configuration of the liquid crystal display device10is described. As shown inFIG. 1, the liquid crystal display device10includes a liquid crystal panel (display panel)11that displays an image, a transparent antenna substrate12placed opposite an outer side (front side) of the liquid crystal panel11and provided with the transparent antenna17, and a backlight device (lighting device)13serving as an external light source that emits light toward the liquid crystal panel11. Of these components, the liquid crystal panel11and the transparent antenna substrate12, which are stacked opposite each other, are firmly fixed to and integrated with each other by a substantially transparent adhesive (not illustrated) sandwiched therebetween. A preferred example of the adhesive is an OCA (optical clear adhesive) tape or the like. Further, the liquid crystal display device10includes a chassis14accommodating the backlight device13, a frame15holding the backlight device13between the chassis14and the frame15, and a bezel16holding the liquid crystal panel11and the transparent antenna substrate12between the frame15and the bezel16.

The liquid crystal display device10according to the present embodiment is one that is used in any of various types of electronic device (not illustrated) such as information displays, electronic blackboards, and television receiving apparatuses. For this purpose, the liquid crystal panel11of the liquid crystal display device10has a screen size of approximately 30-something inches to 50-something inches, which are generally categorized into medium to large sizes. Further, it is preferable that the liquid crystal display device10communicate with an external device under a short-distance radio communication scheme such as NFC (Near Field Communication). Specific examples of external devices that perform short-distance radio communication with the liquid crystal display device10include IC cards, smartphones, and the like each of which contains a device-side antenna. A user is enabled to perform short-distance radio communication between the device-side antenna of an external device such as an IC card or a smartphone and the transparent antenna17by bringing the external device closer to the transparent antenna17in accordance with a display shown on the liquid crystal display device10.

As shown inFIGS. 2 and 3, the liquid crystal panel11has a horizontally long quadrangular shape (rectangular shape) when seen in a plan view and includes a pair of highly translucent glass substrates bonded to each other with a predetermined gap therebetween and a liquid crystal sealed in between the substrates. The liquid crystal panel11is incorporated into the liquid crystal display device10in such a position that the long sides, short sides, and thickness of the liquid crystal panel11extend along the X axis, the Y axis, and the Z axis, respectively. One of the two substrates is a substrate (array substrate) provided with switching elements (e.g. TFTs) connected to source wires and gate wires that are orthogonal to each other, pixel electrodes connected to the switching elements, an alignment film, and the like, and the other of the two substrates is a substrate (CF substrate) provided with a color filter including an predetermined arrangement of colored portions, for example, of R (red), G (green), and B (blue), counter electrodes, an alignment film, and the like. The liquid crystal panel11has its display surface divided into a display region (active area) AA and a non-display region (non-active area) NAA. The display region AA, located in the middle of the screen, is capable of displaying an image, and the non-display region NAA, located at the outer edges of the screen, is in the shape of a frame surrounding the display region AA. Whereas the display region AA has a horizontally long quadrangular shape, the non-display region NAA is in the shape of a horizontally long frame. InFIG. 3, the display region AA is surrounded by a dashed-dotted line, and the non-display region NAA is on the outer side of the dashed-dotted line. The display region AA of the liquid crystal panel11includes a large number of pixels arranged in a matrix along the X axis and the Y axis in the plane of the display surface. These pixels are constituted by the pixel electrodes of the array substrate and the color filter (colored portions) of the CF substrate. It should be noted that a pair of front and back polarizing plates are bonded to outer surfaces of the two substrates, respectively. The backlight device13, which supplies light to the liquid crystal panel11thus configured, includes at least a light source (e.g. cold-cathode tubes, LEDs, organic EL, or the like) and an optical member having an optical function, for example, of transforming emission from the light source into surface emission.

Next, the transparent antenna substrate12and the transparent antenna17provided thereon are described. The transparent antenna substrate12is made of a synthetic resin material such as PET (polyethylene terephthalate), is high in translucency, and is substantially transparent. As shown inFIGS. 2 and 3, the transparent antenna substrate12is in the shape of a sheet that is substantially the same in size and external shape as the liquid crystal panel11when seen in a plan view. It should be noted that, inFIG. 3, the transparent antenna17is illustrated by a dashed line. Therefore, as shown inFIG. 4, the transparent antenna substrate12has a display overlap region OAA that overlaps the display region AA of the liquid crystal panel11when seen in a plan view and a non-display overlap region NOAA that overlaps the non-display region NAA of the liquid crystal panel11when seen in a plan view. The transparent antenna substrate12has a reticulated (meshed) metal film formed on an inner surface thereof, i.e. a surface thereof that faces the liquid crystal panel11, and part of the reticulated metal film constitutes the transparent antenna17. The reticulated metal film is formed by forming a light-blocking solid metal film on the transparent antenna substrate12and then patterning a large number of reticulations (meshes, openings) ME by subjecting the solid metal film to etching and the like and light passing through the reticulations ME allows the transparent antenna substrate12to ensure a certain degree of light transmittance. The large number of reticulations ME patterned in the reticulated metal film are regularly arranged in a matrix in the plane of the transparent antenna substrate12. The planar shape of each of the reticulations ME is a quadrangle. The reticulations ME are placed at diagonal pitches of, for example, approximately 0.5 mm from each other.

As shown inFIG. 4, the reticulated metal film is formed substantially all over the surface of the transparent antenna substrate12in the display overlap region OAA. This makes it difficult for the transparent antenna substrate12to differ in light transmittance (transparency) between an antenna-containing region in which the transparent antenna17is formed and an antenna-free region in which the transparent antenna17is not formed. That is, the display overlap region OAA is a reticulated metal film-containing region. Further, slits SL1forming a grid are formed in the antenna-free region (including a magnetic field generation region MA described below) of the reticulated metal film, and slits SL2for defining the transparent antenna17are formed in the antenna-containing region of the reticulated metal film. The slits SL2will be described later. The width of each of the slits SL1forming the grid is greater than the opening width of each of the reticulations ME. It should be noted thatFIG. 4illustrates the slits SL1and SL2in white. In contrast to this, a light-blocking film (not illustrated) and a non-reticulated metal film (solid metal film) that constitutes an antenna connection wiring part20described below are formed substantially all over the inner surface of the transparent antenna substrate12in the non-display overlap region NOAA. The reticulated metal film and the non-reticulated metal film are made of a highly conductive metal material such as copper.

As shown inFIG. 4, the transparent antenna17has its planar shape and wiring pattern defined by cutting the slits SL2in the antenna-containing region of the reticulated metal film formed on the transparent antenna substrate12. The transparent antenna17includes an antenna body part18and a lead wiring part19. The antenna body part18is in the shape of a ring and generates a magnetic field on a center side thereof, and the lead wiring part19leads from the antenna body part18. The transparent antenna17is configured such that the antenna body part18is placed in a position away from a boundary position between the display overlap region OAA and the non-display overlap region NOAA on the transparent antenna substrate12toward the middle of the screen of the liquid crystal panel11by a predetermined distance along the Y axis and that the lead wiring part19is placed between the boundary position and the antenna body part18. The transparent antenna17is placed in its entirety in the display overlay region OAA of the transparent antenna substrate12. In contrast to this, the non-display overlap region NOAA of the transparent antenna substrate12is provided with an antenna connection wiring part20that is connected to the lead wiring part19of the transparent antenna17. Connecting the antenna connection wiring part20to an antenna power supply circuit (not illustrated) causes the transparent antenna17to be supplied with electric power, i.e. an electric current, for generating a magnetic field.

As shown inFIG. 4, the antenna body part18is in the shape of a closed ring surrounding the magnetic field generation region MA, located on a center side thereof, in which a magnetic field is generated, and the planar shape of the antenna body part18is a vertically long quadrangular shape. The antenna body part18has an inside dimension of, for example, approximately 85.6 mm along the long sides thereof and an inside dimension of, for example, approximately 54 mm along the short sides thereof. Further, the device-side antenna of the external device has substantially the same outside dimensions as the antenna body part18. Therefore, bringing the device-side antenna closer to the antenna body part18in an appropriate plane position (true position) causes the device-side antenna to be placed overlapping the entirety of the magnetic field generation region MA and allows the device-side antenna to capture almost all of the magnetic field generated in the magnetic field generation region MA. The antenna body part18is placed in such a form that its long sides and short sides extend along the Y axis and the X axis, respectively. The antenna body part18includes a pair of short side parts (first side parts)18S extending along an X-axis direction (first direction), a pair of long side parts (second side parts)18L extending along a Y-axis direction (second direction), and four corner parts18C connecting the short side parts18S and the long side parts18L. The antenna body part18allows a magnetic field to be generated in the magnetic field generation region MA by the electromagnetic induction effect of an electric current passed through the four side parts18L and18S. As such, the antenna body part18achieves a higher induced electromotive force than an antenna body part including three side parts. The antenna body part18includes a plurality of (inFIG. 4, four) quadrangularly-ringed antenna wires21radially arranged at spacings corresponding to the slits SL2. The plurality of antenna wires21are similar in planar shape to the antenna body part18. One of the antenna wires21that is closer to the magnetic field generation region MA tends to be smaller in external shape and shorter in distance of surface extension (i.e. the length of each of the side parts18L and18S). On the other hand, one of the antenna wires21that is farther from the magnetic field generation region MA tends to be larger in external shape and longer in distance of surface extension. That is, an antenna wire21that is close to the magnetic field generation region MA is a size larger in external shape than an antenna wire21located adjacent to the antenna wire21on a side that is farther from the magnetic field generation region MA, and is completely surrounded by the adjacent antenna wire21. Each of the antenna wires21has its two ends placed in the short side part18S on the lower side (lead wiring part19side) ofFIG. 4and is connected to a different lead wiring part19. Further, each of the antenna wires21has an axisymmetrical shape with respect to a center line extending along the Y axis.

As shown inFIG. 4, the lead wiring part19is routed in such a form as to extend from the boundary position between the display overplay region OAA and the non-display overlap region NOAA on the transparent antenna substrate12to the antenna body part18substantially straight along the Y-axis direction (second direction), i.e. the direction of extension of the long side parts18L. The lead wiring part19includes a plurality of (inFIG. 4, eight) lead wiring parts19arranged along the X-axis direction (first direction) orthogonal to the direction of extension the lead wiring parts19, and the number of lead wiring parts19provided is twice larger than the number of antenna wires21provided. An end of each of the lead wiring parts19that is on an antenna body part18side (i.e. the side from which the lead wiring part19leads) is connected to an end of the corresponding one of the antenna wires21, and an end of each of the lead wiring parts19that is on an opposite side (i.e. the side to which the lead wiring part19leads or a boundary position side) is connected to the antenna connection wiring part20. Further, a dummy wiring part DW electrically isolated from the transparent antenna17is placed in such a form as to be interposed between two of the lead wiring parts19that are closest to the middle in the direction (X-axis direction) along which they are arranged.

As shown inFIG. 4, the antenna connection wiring part20is constituted by the non-reticulated metal film formed in the non-display overlap region NOAA of the transparent antenna substrate12. Therefore, the antenna connection wiring part20is relatively lower in wiring resistance per unit length or per unit area than the antenna body part18and the lead wiring parts19of the transparent antenna17formed by the reticulated metal film. The antenna connection wiring part20includes a plurality (inFIG. 4, three) short-circuit wiring parts22that short-circuit two lead wiring parts19. The number of short-circuit wiring parts22provided takes on a value obtained by subtracting 2 from the number of lead wiring parts19provided. Two lead wiring parts19that are short-circuited by the short-circuit wiring parts22are connected to different antenna wires21. Specifically, the lead wiring part19connected to a first end (on the left side ofFIG. 4) of the outermost antenna wire21is short-circuited by the short-circuit wiring parts22with the lead wiring part19connected to a first end (on the right side ofFIG. 4) of the second outermost antenna wire21. The lead wiring part19connected to a second end (on the left side ofFIG. 4) of the second outermost antenna wire21is short-circuited by the short-circuit wiring parts22with the lead wiring part19connected to a first end (on the right side ofFIG. 4) of the second innermost (i.e. third outermost) antenna wire21. The lead wiring part19connected to a second end (on the left side ofFIG. 4) of the second innermost antenna wire21is short-circuited by the short-circuit wiring parts22with the lead wiring part19connected to a first end (on the right side ofFIG. 4) of the innermost antenna wire21. Moreover, the antenna connection wiring part20includes an input wiring part (not illustrated) connected to the lead wiring part19connected to a second end (on the right side ofFIG. 4) of the outermost antenna wire21and an output wiring part (not illustrated) connected to the lead wiring part19connected to the first end (on the left side ofFIG. 4) of the innermost antenna wire21. All this causes an electric current flowing from the input wiring part to flow to the second outermost antenna wire21through the lead wiring part19and the short-circuit wiring parts22in a counterclockwise direction ofFIG. 4after flowing to the outermost antenna wire21through the lead wiring part19in the counterclockwise direction ofFIG. 4and then flow to the output wiring part after flowing to the second innermost antenna wire21through the lead wiring part19and the short-circuit wiring parts22in the counterclockwise direction ofFIG. 4and further flowing to the innermost antenna wire21through the lead wiring part19and the short-circuit wiring parts22in the counterclockwise direction ofFIG. 4. Such a flow of an electric current through the antenna body part18in the counterclockwise direction ofFIG. 4generates, in the magnetic field generation region MA of the antenna body part18, a magnetic field directed toward the near side of the paper surface ofFIG. 4.

Incidentally, the Q value, which represents the antenna performance of the transparent antenna17, is represented by formula “2πfL/R”, where “L” is the inductance (induced electromotive force, “R” is the wiring resistance, and “f” is the resonant frequency. That is, the Q value tends to be proportional to the inductance and inversely proportional to the wiring resistance. This shows that the antenna performance of the transparent antenna17is effectively improved by increasing the inductance or lowering the wiring resistance. In particular, while the wiring resistance of the transparent antenna17is effectively lowered, for example, by reducing the opening area of the reticulations ME in the reticulated metal film constituting the transparent antenna17(i.e. the opening ratio of the transparent antenna17), doing so undesirably invites a decrease in amount of light that is transmitted through the reticulations ME and, by extension, a decrease in light transmittance of the transparent antenna17. On the other hand, increasing the opening area of the reticulations ME in the reticulated metal film to improve the light transmittance of the transparent antenna17undesirably invites an increase in wiring resistance of the transparent antenna17and, by extension, a decrease in antenna performance of the transparent antenna17.

To address these problems, as shown inFIGS. 5 to 7, the transparent antenna17according to the present embodiment is configured such that when each of the antenna wires21is configured to have a first extension part23extending along the direction of extension of the antenna wire21and a second extension part24extending along a direction intersecting with the direction of extension, the per unit length area of the first extension part23is larger than the per unit length area of the second extension part24. The influence on the wiring resistance of the per unit length area of the first extension part23, of the antenna wire21, which extends along the direction of extension of the antenna wire21, is relatively greater than the influence on the wiring resistance of the per unit length area of the second extension part24, of the antenna wire21, which extends along a direction intersecting with the direction of extension. Therefore, such a configuration in which the per unit length area of the first extension part23is larger than the per unit length area of the second extension part24makes it possible, at least in the antenna body part18, to efficiently lower the wiring resistance while sufficiently securing the opening area of the reticulations ME. This in turn makes it possible to achieve a reduction in wiring resistance while achieving sufficient light transmittance. It should be noted that sinceFIG. 6is an enlarged plan view of a short side part (first side part)18S of the antenna body part18, the direction of extension of the antenna wire21coincides with the X-axis direction inFIG. 6. On the other hand, sinceFIG. 7is an enlarged plan view of a long side part (second side part)18L of the antenna body part18, the direction of extension of the antenna wire21coincides with the Y-axis direction inFIG. 7.

As shown inFIG. 5, such first and second extension parts23and24differing in per unit length area from each other are had by the antenna wire21in each of the long and short side parts18L and18S, but not in any of the corner parts18C. For this reason, it can be said that the first extension part23is a “side-part first extension part” and the second extension part24is a “side-part second extension part”. Each of the corner parts18C of the antenna wire21has a corner-part first extension part28extending parallel to a short side direction (first direction) of the antenna body part18and a corner-part second extension part29extending parallel to a long side direction (second direction) of the antenna body part18, and is configured such that the corner-part first extension part28and the corner-part second extension part29are equal in per unit length area to each other. Therefore, in each of the corner parts18C, there are no such first and second extension parts23and24differing in per unit length area from each other.

As shown inFIG. 5, the reticulated metal film constituting the transparent antenna17has a larger number of demarcation parts25demarcating the large number of reticulations ME planarly arranged in a matrix. Those of the demarcation parts25which constitute the long and short side parts18L and18S of the antenna wire21are constituted by first demarcation parts (side-part first demarcation parts)26extending along the direction of extension of the antenna wire21and second demarcation parts (side-part second demarcation parts)27extending along a direction intersecting with the direction of extension of the antenna wire21. In the present embodiment, since the planar shape of each of the reticulations ME is a quadrangular shape, a demarcation part25demarcating a reticulation ME in each of the side parts18L and18S is constituted by a pair of first demarcation parts26and a pair of second demarcation parts27whose directions of extension are orthogonal to each other. Whereas the first demarcation parts26extend substantially straight along the direction of extension of the antenna wire21, the second demarcation parts27extend substantially straight along a direction intersecting with the direction of extension of the antenna wire21. As shown inFIGS. 6 and 7, the spacing L1between adjacent first demarcation parts26with a reticulation ME interposed therebetween is substantially equal to the spacing L2between adjacent second demarcation parts27with a reticulation ME interposed therebetween. Meanwhile, those of the demarcation parts25which constitute the corner parts18C of the antenna wire21have corner-part first demarcation parts30extending parallel to the short side direction (first direction) of the antenna body part18and corner-part second demarcation parts31extending parallel to the long side direction (second direction) of the antenna body part18. In the present embodiment, since the planar shape of each of the reticulations ME is a quadrangular shape, a demarcation part25demarcating a reticulation ME in each of the corner parts18C is constituted by a pair of corner-part first demarcation parts30and a pair of corner-part second demarcation parts31whose directions of extension are orthogonal to each other. As shown inFIG. 8, the spacing L3between adjacent corner-part first demarcation parts30with a reticulation ME interposed therebetween is substantially equal to the spacing L4between adjacent corner-part second demarcation parts31with a reticulation ME interposed therebetween.

Moreover, as shown inFIGS. 6 and 7, each of the first demarcation parts26, which constitute each of the long and short side parts18L and18S of the antenna wire21, is configured to have a line width W1that is relatively greater than a line width W2of each of the second demarcation parts27. Therefore, the per unit length area of the first demarcation part26is relatively larger than the per unit length area of the second demarcation part27. Whereas the first extension part23that the antenna wire21has in each of its side parts18L and18S is constituted by all of the first demarcation parts26provided in the corresponding one of the side parts18L and18S, the second extension part24that the antenna wire21has in each of its side parts18L and18S is constituted by all of the second demarcation parts27provided in the corresponding one of the side parts18L and18S. Therefore, whereas the first extension part23is relatively large in per unit length area, the second extension part24is relatively small in per unit length area. Meanwhile, as shown inFIG. 8, each of the corner-part first demarcation parts30, which constitute each the corner parts18C of the antenna wire21, is configured to have a line width W3that is substantially equal to a line width W4of each of the corner-part second demarcation parts31. Therefore, the per unit length area of the corner-part first demarcation part30is substantially equal to the per unit length area of the corner-part second demarcation part31. Whereas the corner-part first extension part28that the antenna wire21has in each of its corner parts18C is constituted by all of the corner-part first demarcation parts30provided in the corresponding one of the corner parts18C, the corner-part second extension part29that the antenna wire21has in each of its corner parts18C is constituted by all of the corner-part second demarcation parts31provided in the corresponding one of the corner parts18C. Therefore, the corner-part first extension parts28and the corner-part second extension parts29are substantially equal in per unit length area to each other.

Specifically, as shown inFIG. 6, the first extension part23that the antenna wire21has in each of its short side parts18S comprises a plurality of first demarcation parts26extending along the X-axis direction, which is the direction of extension of the short side part18S. Therefore, the line width W1of each of the first demarcation parts26is wider than the line width W2of each of the second demarcation parts27extending along the Y-axis direction orthogonal to the direction of extension of the short side part18S, whereby the per unit length area of the first extension part23is larger than the per unit length area of the second extension part24comprising the plurality of second demarcation parts27. On the other hand, as shown inFIG. 7, the first extension part23that the antenna wire21has in each of its long side parts18L comprises a plurality of first demarcation parts26extending along the Y-axis direction, which is the direction of extension of the long side part18L. Therefore, the line width W1of each of the first demarcation parts26is greater than the line width W2of each of the second demarcation parts27extending along the Y-axis direction orthogonal to the direction of extension of the long side part18L, whereby the per unit length area of the first extension part23is larger than the per unit length area of the second extension part24comprising the plurality of second demarcation parts27.

Furthermore, as shown inFIG. 9, the transparent antenna17is configured such that when each of the lead wiring parts19is configured to have a first lead extension part32extending along the direction of extension of the lead wiring part19and a second lead extension part33extending along a direction intersecting with the direction of extension, the per unit length area of the first lead extension part32is larger than the per unit length area of the second lead extension part33. The demarcation part25that this lead wiring part19has is identical in configuration to the demarcation part25that the antenna wire21has in each of its side parts18L and18S and, as such, comprises first demarcation parts26whose line width W1is relatively great and second demarcation parts27whose line width W2is relatively small. It should be noted that, for convenience, the demarcation parts26and27that the lead wiring part19has are given the same reference signs as those given to the demarcation parts26and27that the antenna wire21has in each of its side parts18L and18S. For this reason, the first lead extension part32comprises a plurality of first demarcation parts26extending along the Y-axis direction, which is the direction of extension of the lead wiring part19. Therefore, the line width W1of each of the first demarcation parts26is greater than the line width W2of each of the second demarcation parts27extending along the Y-axis direction orthogonal to the direction of extension of the lead wiring part19, whereby the per unit length area of the first lead extension part32is larger than the per unit length area of the second lead extension part33comprising the plurality of second demarcation parts27. This makes it possible, in the lead wiring part19, too, to efficiently lower the wiring resistance while sufficiently securing the opening area of the reticulations ME.

The following describes Comparative Experiment 1, which was conducted to find out how the opening ratio of the transparent antenna17thus configured varies according to the line width of each of the demarcation parts26and27. In Comparative Experiment 1, Comparative Example is a transparent antenna whose antenna body part includes antenna wires each having, in each of its side parts, first and second demarcation parts that are equal in line width to each other, and Example 1 is a transparent antenna17whose antenna body part18includes antenna wires21each having, in each of its side parts18L and18S, first and second demarcation parts26and27with each of the first demarcation parts26having a line width W1that is greater than a line width W2of each of the second demarcation parts27, i.e. a transparent antenna17described in the preceding paragraphs. In Comparative Experiment 1, the line width W1of each of the first demarcation parts26of Example 1 is equal to the line width of each of the demarcation parts of Comparative Example, and the line width W2of each of the second demarcation parts27of Example 1 takes on such a value that the wiring resistance of the transparent antenna17of Example 1 is equal to the wiring resistance of the transparent antenna of Comparative Example. In Comparative Example and Example 1, the spacings between adjacent first demarcation parts with a reticulation interposed therebetween and the spacings between adjacent second demarcation parts with a reticulation interposed therebetween are all identical.FIG. 10shows the results of calculation of the opening ratio of each of the transparent antennas of Comparative Example and Example 1 with varying line widths of each demarcation part.

InFIG. 10, the horizontal axis represents the line width of each demarcation part (in units of “μm”), and the vertical axis represents the opening ratio of each of the transparent antennas (no unit of quantity required). Specifically, in terms of Comparative Example, the horizontal axis ofFIG. 10represents the line width of each demarcation part, and in terms of Example 1, the horizontal axis ofFIG. 10represents the line width W1of each first demarcation part26. The term “opening ratio of a transparent antenna” here means the ratio of the total area of all of the reticulations ME included in the transparent antenna to the area of the region of the transparent antenna substrate in which the transparent antenna is formed. InFIG. 10, the graphs of Comparative Example and Example 1 are identical in wiring resistance at the same position on the horizontal axis. InFIG. 10, the wiring resistance tends to become lower rightward on the horizontal axis (as the line width becomes greater), and on the other hand, the wiring resistance tends to become higher leftward on the horizontal axis (as the line width becomes narrower). InFIG. 10, the solid line graph represents the experimental result of Example 1, and the dashed line graph represents the experimental result of Comparative Example. The opening ratio of each of the transparent antennas of Comparative Example and Example 1 was calculated in the following manner. In Comparative Example, the opening ratio of the transparent antenna was calculated from formula “(Lref−Wref)2/Lref2”, where “Lref” is the spacing between adjacent first demarcation parts with a reticulation interposed therebetween and the spacing between adjacent second demarcation parts with a reticulation interposed therebetween and “Wref” is the line width of each first demarcation part and the line width of each second demarcation part. In Example 1, the opening ratio of the transparent antenna17was calculated from formula “(L1−W1)(L2−W2)/L1·L2”, where “L1” is the spacing between adjacent first demarcation parts26with a reticulation ME interposed therebetween, “L2” is the spacing between adjacent second demarcation parts27with a reticulation ME interposed therebetween, “W1” is the line width of each first demarcation part26, and “W2” is the line width of each second demarcation part27. It should be noted that, in Comparative Experiment 1, formulas “W1=Wref>W2” and “L1=L2=Lref” hold.

Here are the experimental results of Comparative Experiment 1. According toFIG. 10, the opening ratio of each of the transparent antennas of Comparative Example and Example 1 tend to become gradually lower with increase in line width of each demarcation part. Moreover, Example 1 is gentler in slope of the graph and slower in decrease of the opening ratio of the transparent antenna entailed by an increase in line width of each demarcation part than Comparative Example. Therefore, the difference in opening ratio between the transparent antennas of Example 1 and Comparative Example tends to become greater with increase in line width W1or W2of each demarcation part26or27. In Example 1, since the line width W2of each second demarcation part27is narrower than the line width W1of each first demarcation part26, the opening ratio of the transparent antenna17is higher by the difference between the line widths W1and W2. In Comparative Example, on the other hand, it is conceivable that the same opening ratio may be achieved, for example, by causing the line width Wref of each demarcation part to take on a value that is narrower than W1and greater than W2. However, doing so makes it impossible to sufficiently ensure the line width of each first demarcation part, which exerts a great (dominant) influence on the wiring resistance of the antenna wire, thus posing a risk of increase in wiring resistance. In that respect, Example 1 makes it possible to efficiently lower the wiring resistance, as the line width W1of each first demarcation part26, which exerts a great (dominant) influence on the wiring resistance of the antenna wire21, is greater than the line width W2of each second demarcation part27, which exerts a small (subordinate) influence on the wiring resistance of the antenna wire21. Therefore, in Example 1, the wiring resistance can be made relatively lower if the opening ratio of the transparent antenna17is equal to the opening ratio of the transparent antenna of Comparative Example, and the opening ratio of the transparent antenna17can be made relatively higher if the wiring resistance is equal to the wiring resistance of Comparative Example. Thus, Example 1 makes it possible to sufficiently reduce the wiring resistance while sufficiently ensuring the opening ratio, i.e. light transmittance, of the transparent antenna17.

As described above, a transparent antenna17according to the present embodiment includes an antenna wire21, formed by a reticulated metal film in a shape of a ring, which generates a magnetic field on a center side thereof. The antenna wire21has a first extension part23extending along a direction of extension of the antenna wire21and a second extension part24extending along a direction intersecting with the direction of extension. The antenna wire21is configured such that a per unit length area of the first extension part23is larger than a per unit length area of the second extension part24.

In this way, the flow of an electric current through the ring-shaped antenna wire21causes a magnetic field to be generated on the center side of the antenna wire21by an electromagnetic induction effect. The antenna wire21is formed by the reticulated metal film, which has reticulations ME through which light is transmitted, whereby the translucency of the transparent antenna17is secured. The wiring resistance of the antenna wire21tends to become lower as the opening area of the reticulations ME in the metal film becomes smaller and the area of the metal film becomes larger, and tends to become higher as the opening area of the reticulations ME in the metal film becomes larger and the area of the metal film becomes smaller. Note here that the influence on the wiring resistance of the per unit length area of the first extension part23, of the antenna wire21, which extends along the direction of extension of the antenna wire21, is relatively greater than the influence on the wiring resistance of the per unit length area of the second extension part24, of the antenna wire21, which extends along a direction intersecting with the direction of extension.

Moreover, since the antenna wire21is configured such that the per unit length area of the first extension part23, which extends along the direction of extension of the antenna wire21, is larger than the per unit length area of the second extension part24, which extends along a direction intersecting with the direction of extension, it is possible to efficiently lower the wiring resistance while sufficiently securing the opening area of the reticulations ME. This makes it possible to achieve a reduction in wiring resistance while achieving sufficient light transmittance.

Further, the antenna wire21has a plurality of reticulations ME and a plurality of demarcation parts25demarcating the reticulations ME, the demarcation parts25being each constituted by a first demarcation part26extending along the direction of extension and a second demarcation part27extending along a direction intersecting with the direction of extension, the first extension part23comprises a plurality of the first demarcation parts26, and the second extension part24comprises a plurality of the second demarcation parts27. In this way, the per unit length area of the first extension part23comprising the plurality of first demarcation parts26is larger than the per unit length area of the second extension part24comprising the plurality of second demarcation parts27. This makes it possible to efficiently lower the wiring resistance while sufficiently securing the opening area of the reticulations ME. This in turn makes it possible to achieve a reduction in wiring resistance while achieving sufficient light transmittance.

Further, the first demarcation part26has a line width W1that is greater than a line width W2of the second demarcation part27. In this way, by making the line width W1of the first demarcation part26wider than the line width W2of the second demarcation part27, the per unit length area of the first extension part23comprising a plurality of the first demarcation parts26can be made larger than the per unit length area of the second extension part24comprising a plurality of the second demarcation parts27.

Further, the antenna wire21has a planar shape forming a quadrangular ring and has a pair of short side parts (first side parts)18S extending parallel to a first direction and a pair of long side parts (second side parts)18L extending parallel to a second direction orthogonal to the first direction, the short side parts18S are each configured such that the first demarcation part26extends along the first direction and the second demarcation part27extends along the second direction, and the long side parts18L are each configured such that the first demarcation part26extends along the second direction and the second demarcation part27extends along the first direction. In this way, in each of the short side parts18S, of the antenna wire21having a planar shape forming a quadrangular ring, which extend parallel to the first direction, the per unit length area of the first extension part23comprising a plurality of the first demarcation parts26extending along the first direction is larger than the per unit length area of the second extension part24comprising a plurality of the second demarcation parts27extending along the second direction orthogonal to the first direction. On the other hand, in each of the long side parts18L, of the antenna wire21, which extend parallel to the second direction, the per unit length area of the first extension part23comprising a plurality of the first demarcation parts26extending along the second direction is larger than the per unit length area of the second extension part24comprising a plurality of the second demarcation parts27extending along the first direction. This makes it possible to achieve a reduction in wiring resistance while achieving sufficient light transmittance.

Further, the antenna wire21has a planar shape forming a quadrangular ring and has a pair of short side parts18S extending parallel to a first direction, a pair of long side parts18L extending parallel to a second direction orthogonal to the first direction, and corner parts18C connecting the short side parts18S and the long side parts18L, the short side parts18S and the long side parts18L each have the first extension part23and the second extension part24, the corner parts18C each have a corner-part first extension part28extending parallel to the first direction and a corner-part second extension part29extending parallel to the second direction, and the corner parts18C are each configured such that the corner-part first extension part28and the corner-part second extension part29are equal in per unit length area to each other. In this way, since the short side parts18S extend parallel to the first direction and the long side parts18L extend parallel to the second direction orthogonal to the first direction, the per unit length area of the first extension part23in each of the short and long side parts18S and18L is larger than the per unit length area of the second extension part24in each of the short and long side parts18S and18L. This makes it possible to efficiently lower the wiring resistance while sufficiently securing the opening area of the reticulations ME in the short side parts18S and the long side parts18L. Meanwhile, since the corner parts18C connect the short side parts18S and the long side parts18L, the corner-part first extension part28and the corner-part second extension part29are equal in per unit length area to each other. This makes it difficult for the short side parts18S and the long side parts18L to differ from each other in terms of the opening area of the reticulations ME and the wiring resistance.

Further, the corner parts18C are each configured such that the per unit length area of the corner-part first extension part28is smaller than the per unit length area of the first extension part23constituting the short side parts18S and the long side parts18L and the per unit length area of the corner-part second extension part29is larger than the per unit length area of the second extension part24constituting the short side parts18S and the long side parts18L. In this way, the per unit length areas of the corner-part first and second extension parts28and29constituting the corner part18C are appropriate. This makes it more difficult for the short side parts18S and the long side parts18L to differ from each other in terms of the opening area of the reticulations ME and the wiring resistance.

Further, a lead wiring part19extending in such a form as to lead from the antenna wire21is further included, the lead wiring part19has a first lead extension part32extending along a direction of extension of the lead wiring part19and a second lead extension part33extending along a direction intersecting with the direction of extension of the lead wiring part19, and the lead wiring part19is configured such that a per unit length area of the first lead extension part32is larger than a per unit length area of the second lead extension part33. In this way, the flow of an electric current through the ring-shaped antenna wire21due to the passage of electricity through the lead wiring part19causes a magnetic field to be generated on the center side of the antenna wire21by an electromagnetic induction effect. This lead wiring part19is configured such that the per unit length area of the first lead extension part32extending along the direction of extension of the lead wiring part19is larger than the per unit length area of the second lead extension part33extending along a direction intersecting with the direction of extension of the lead wiring part19. This makes it possible to efficiently lower the wiring resistance while sufficiently securing the opening area of the reticulations ME. This in turn makes it possible to achieve a reduction in wiring resistance while achieving sufficient light transmittance.

Further, a liquid crystal display device (transparent antenna-equipped display device)10according to the present embodiment includes: the transparent antenna17described above; a transparent antenna substrate12provided with the transparent antenna17; and a liquid crystal panel (display panel)11, stacked on the transparent antenna substrate12, which has a display region AA that is capable of displaying an image and a non-display region NAA surrounding the display region AA. The transparent antenna17is placed in a position overlapping the display region AA.

In this way, the use of the transparent antenna17placed in a position overlapping the display region AA of the liquid crystal panel11makes it possible to perform communication, for example, with an external device or the like. This makes it possible to perform an operation such as bringing the external device closer to the transparent antenna17in accordance with an image displayed on the display region AA, thus offering great convenience. Moreover, the antenna performance of the transparent antenna17is so high that communication with the external device or the like can be satisfactorily performed.

Embodiment 2 of the present invention is described with reference toFIGS. 11 to 13. Embodiment 2 illustrates a different arrangement of demarcation parts126and127in each side part118L or118S. It should be noted that a repeated description of structures, actions, and effects which are similar to those of Embodiment 1 described above is omitted.

As shown inFIGS. 11 and 12, an antenna wire121according to the present embodiment is configured such that, in the demarcation parts126and127constituting the side parts118L and118S, the spacing L5between adjacent second demarcation parts127with a reticulation ME interposed therebetween (i.e. the length of each of the first demarcation parts126) is wider (greater) than the spacing L1between adjacent first demarcation parts126with a reticulation ME interposed therebetween (i.e. the length of each of the second demarcation parts127). Therefore, whereas a reticulation ME defined by demarcation parts126and127in each of the short side parts118S has a horizontally long quadrangular shape (FIG. 11), a reticulation ME defined by demarcation parts126and127in each of the long side parts118L has a vertically long quadrangular shape (FIG. 12). This allows the opening area of the reticulations ME to be larger by the expansion (L5−L1) of the spacing L5between adjacent second demarcation parts127with a reticulation ME interposed therebetween than in Embodiment 1 described above. This allows the transparent antenna to have a higher opening ratio. Moreover, the opening area of the reticulations ME can be ensured as usual, for example, by adjusting the spacing L5between adjacent second demarcation parts127with a reticulation ME interposed therebetween to take on such a value as to compensate for a decrease in the opening area of the reticulations ME attributed to the difference between the line width W1of each of the first demarcation parts126and the line width W2of each of the second demarcation parts127.

The following describes Comparative Experiment 2, which was conducted to find out how the opening ratio of the transparent antenna thus configured varies according to the line width of each of the demarcation parts126and127. In addition to Comparative Example and Example 1 of Comparative Experiment 1 described above, Comparative Experiment 2 used Example 2, which is a transparent antenna configured such that the spacing L5between adjacent second demarcation parts127with a reticulation ME interposed therebetween is wider than the spacing L1between adjacent first demarcation parts126with a reticulation ME interposed therebetween, i.e. a transparent antenna described in the preceding paragraphs. In Comparative Experiment 2, the spacing L1between adjacent first demarcation parts126with a reticulation ME interposed therebetween in Example 2 is equal to the spacings between adjacent first demarcation parts with a reticulation interposed therebetween and the spacings between adjacent second demarcation parts with a reticulation interposed therebetween in Comparative Example and Example 1.FIG. 13shows the results of calculation of the opening ratio of each of the transparent antennas of Comparative Example and Examples 1 and 2 with varying line widths of each demarcation part.

InFIG. 13, the horizontal axis represents the line width of each demarcation part (in units of “μm”), and the vertical axis represents the opening ratio of each of the transparent antennas (no unit of quantity required), as inFIG. 10of Comparative Experiment 1. It should be noted that, in terms of Example 2, the horizontal axis ofFIG. 13represents the line width W1of each first demarcation part126. InFIG. 13, the solid line graph represents the experimental result of Example 2, the dashed-dotted line graph represents the experimental result of Example 1, and the dotted line graph represents the experimental result of Comparative Example. The opening ratio of the transparent antenna of Example 2 was calculated as follows: The opening ratio of the transparent antenna was calculated from formula “(L1−W1)(L5−W2)/L1·L2”, where “L1” is the spacing between adjacent first demarcation parts126with a reticulation ME interposed therebetween, “L2” is the spacing between adjacent second demarcation parts127with a reticulation ME interposed therebetween, “W1” is the line width of each first demarcation part126, and “W2” is the line width of each second demarcation part127. It should be noted that, in Comparative Experiment 2, formulas “W1=Wref>W2” and “L5>L1=Lref” hold.

Here are the experimental results of Comparative Experiment 2. According toFIG. 13, the opening ratio of the transparent antenna of Example 2 is held substantially constant even with increase in line width W1or W2of each demarcation part126or127. Therefore, the difference in opening ratio between the transparent antenna of Example 2 and the transparent antennas of Example 1 and Comparative Example tends to become greater with increase in line width W1or W2of each demarcation part126or127. In Example 2, since the spacing L5between adjacent second demarcation parts127with a reticulation ME interposed therebetween is wider than the spacing L1between adjacent first demarcation parts126with a reticulation ME interposed therebetween, the opening ratio of the transparent antenna is higher by the difference between the spacings L1and L5. Moreover, it is preferable that the spacing L5between adjacent second demarcation parts127with a reticulation ME interposed therebetween be set by being calculated from formula “W2/(1−AR·L1/(L1−W1)), where “AR” is the target value of the opening ratio of the transparent antenna. Doing so makes it possible to hold the opening ratio of the transparent antenna constant regardless of whether the line widths W1and W2of the demarcation parts126and127are large or small, as indicated by the solid line graph inFIG. 13. All this makes it possible to ensure the opening ratio, i.e. light transmittance, of the transparent antenna as usual while keeping the wiring resistance sufficiently low.

According to the present embodiment, as described above, the spacing L5between adjacent second demarcation parts127is wider than the spacing L1between adjacent first demarcation parts126. In this way, by making the spacing L5between adjacent second demarcation parts127wider than the spacing L1between adjacent first demarcation parts126, the opening area of the reticulations ME can be expanded. This makes it possible to suitably achieve a reduction in wiring resistance by making the line width W1of each of the first demarcation parts126relatively wider and to, by making the spacing L5between adjacent second demarcation parts127relatively wider, ensure the opening area of the reticulation ME as usual while maintaining the wiring resistance.

Embodiment 3 of the present invention is described with reference toFIGS. 14 to 16. Embodiment 3 illustrates a different line width and arrangement of demarcation parts226and227in each side part218L or218S from Embodiment 1 described above. It should be noted that a repeated description of structures, actions, and effects which are similar to those of Embodiment 1 described above is omitted.

As shown inFIGS. 14 and 15, an antenna wire221according to the present embodiment is configured such that, in the demarcation parts226and227constituting the side parts218L and218S, the line width W5of each of the first demarcation parts226is equal to the line width W2of each of the second demarcation parts227and the spacing L6between adjacent second demarcation parts227with a reticulation ME interposed therebetween (i.e. the length of each of the first demarcation parts226) is wider (longer) than the spacing L1between adjacent first demarcation parts226with a reticulation ME interposed therebetween (i.e. the length of each of the second demarcation parts227). Therefore, whereas a reticulation ME defined by demarcation parts226and227in each of the short side parts218S has a horizontally long quadrangular shape (FIG. 14), a reticulation ME defined by demarcation parts226and227in each of the long side parts218L has a vertically long quadrangular shape (FIG. 15). In other words, since the spacing L1between adjacent first demarcation parts226with a reticulation ME interposed therebetween is narrower than the spacing L6between adjacent second demarcation parts227with a reticulation ME interposed therebetween, the number of first demarcation parts226that are had by a first extension part223is larger than the number of second demarcation parts227that are had by a second extension part224. This allows the per unit length area of the first extension part223comprising the plurality of first demarcation parts226to be larger than the per unit length area of the second extension part224comprising the plurality of second demarcation parts227. It is preferable that when the spacing L1between adjacent first demarcation parts226with a reticulation ME interposed therebetween is expressed by formula “Lref/a” (where “a” is a variable of 1 or larger), the spacing L6between adjacent second demarcation parts227with a reticulation ME interposed therebetween be calculated according to formula “a·Lref”, where “Lref” is the reference spacing. The variable “a” is hereinafter referred to as “ratio variable” for convenience.

The following describes Comparative Experiment 3, which was conducted to find out how the opening ratio of the transparent antenna thus configured varies according to the ratio variable a of the spacings L1and L6between demarcation parts226and between demarcation parts227. Comparative Experiment 3 used Comparative Example of Comparative Experiment 1 described above and Example 3, which is a transparent antenna configured such that the line width W5of each of the first demarcation parts226is equal to the line width W2of each of the second demarcation parts227and the spacing L6between adjacent second demarcation parts227with a reticulation ME interposed therebetween is wider than the spacing L1between adjacent first demarcation parts226with a reticulation ME interposed therebetween, i.e. a transparent antenna described in the preceding paragraphs. In Comparative Experiment 3, whereas the spacings between demarcation parts in Comparative Example both take on values calculated according to formula “Lref/a”, the spacing L1between adjacent first demarcation parts226with a reticulation ME interposed therebetween in Example 3 takes on a value calculated according to formula “Lref/a” and the spacing L6between adjacent second demarcation parts227with a reticulation ME interposed therebetween in Example 3 takes on a value calculated according to formula “a·Lref”.FIG. 16shows the results of calculation of the opening ratio of each of the transparent antennas of Comparative Example and Example 3 with variations of this ratio variable a. It should be noted that the spacing L1between adjacent first demarcation parts226with a reticulation ME interposed therebetween in Example 3 is equal to the spacing between adjacent first demarcation parts with a reticulation interposed therebetween and the spacing between adjacent second demarcation parts with a reticulation interposed therebetween in Comparative Example. Further, the line widths W2and W5of the demarcation parts226and227of Example 3 are equal to the line width of each of the demarcation parts of Comparative Example.

InFIG. 16, the horizontal axis represents the ratio variable a (no unit of quantity required), and the vertical axis represents the opening ratio of each of the transparent antennas (no unit of quantity required). InFIG. 16, the graphs of Comparative Example and Example 3 are identical in wiring resistance at the same position on the horizontal axis. InFIG. 16, the wiring resistance tends to become lower rightward on the horizontal axis (as the ratio variable a becomes larger), and on the other hand, the wiring resistance tends to become higher leftward on the horizontal axis (as the ratio variable a becomes smaller). InFIG. 16, the solid line graph represents the experimental result of Example 3, and the dashed line graph represents the experimental result of Comparative Example. The opening ratio of the transparent antenna of Example 3 was calculated as follows: the opening ratio of the transparent antenna was calculated from formula “(L1−W5)(L6−W2)/L1·L6”, where “L1” is the spacing between adjacent first demarcation parts226with a reticulation ME interposed therebetween, “L6” is the spacing between adjacent second demarcation parts227with a reticulation ME interposed therebetween, “W5” is the line width of each first demarcation part226, and “W2” is the line width of each second demarcation part227. It should be noted that, in Comparative Experiment 3, formulas “W5=W2=Wref” and “L6=a·Lref>L1=Lref/a” hold.

Here are the experimental results of Comparative Experiment 3. According toFIG. 16, the opening ratio of each of the transparent antennas of Comparative Example and Example 3 tend to become gradually lower with increase in ratio variable a. Moreover, Example 3 is gentler in slope of the graph and slower in decrease of the opening ratio of the transparent antenna entailed by an increase in ratio variable a than Comparative Example. Therefore, the difference in opening ratio between the transparent antennas of Example 3 and Comparative Example tends to become greater in proportion to the magnitude of the ratio variable a. In Example 3, since the spacing L6between adjacent second demarcation parts227with a reticulation ME interposed therebetween is wider than the spacing L1between adjacent first demarcation parts226with a reticulation ME interposed therebetween, the opening ratio of the transparent antenna is higher by the difference between the spacings L1and L6, although the line widths W2and W5of the demarcation parts226and227are equal. In Comparative Example, on the other hand, it is conceivable that the same opening ratio may be achieved, for example, by reducing the ratio variable a to widen the spacings between demarcation parts. However, doing so makes it impossible to sufficiently ensure the number of first demarcation parts, which exerts a great (dominant) influence on the wiring resistance of the antenna wire, thus posing a risk of increase in wiring resistance. In that respect, Example 3 makes it possible to efficiently lower the wiring resistance, as the spacing L1between first demarcation parts226, which exerts a great (dominant) influence on the wiring resistance of the antenna wire221, is narrower than the spacing L6between second demarcation parts227, which exerts a small (subordinate) influence on the wiring resistance of the antenna wire221, and the number of first demarcation parts226that the first extension part223has is larger than the number of second demarcation parts227that the second extension part224has. Therefore, in Example 3, the wiring resistance can be made relatively lower if the opening ratio of the transparent antenna is equal to the opening ratio of the transparent antenna of Comparative Example, and the opening ratio of the transparent antenna can be made relatively higher if the wiring resistance is equal to the wiring resistance of Comparative Example. Thus, Example 3 makes it possible to sufficiently reduce the wiring resistance while sufficiently ensuring the opening ratio, i.e. light transmittance, of the transparent antenna.

According to the present embodiment, as described above, the spacing L1between adjacent first demarcation parts226is narrower than the spacing L6between adjacent second demarcation parts227. In this way, by making the spacing L1between adjacent first demarcation parts226narrower than the spacing L6between adjacent second demarcation parts227, the number of first demarcation parts226provided is made larger than the number of second demarcation parts227provided. This allows the per unit length area of the first extension part223comprising the plurality of first demarcation parts226to be larger than the per unit length area of the second extension part224comprising the plurality of second demarcation parts227.

Embodiment 4 of the present invention is described with reference toFIGS. 17 to 19. Embodiment 4 illustrates a different arrangement of demarcation parts326and327in each side part318L or318S from Embodiment 3 described above. It should be noted that a repeated description of structures, actions, and effects which are similar to those of Embodiment 3 described above is omitted.

As shown inFIGS. 17 and 18, an antenna wire321according to the present embodiment is configured such that, in the demarcation parts326and327constituting the side parts318L and318S, the spacing L7between adjacent second demarcation parts327with a reticulation ME interposed therebetween is defined by a ratio variable b that is different from the ratio variable a defining the spacing L1between adjacent first demarcation parts326with a reticulation ME interposed therebetween. It is preferable that when the spacing L1between adjacent first demarcation parts326with a reticulation ME interposed therebetween is expressed by formula “Lref/a”, the spacing L7between adjacent second demarcation parts327with a reticulation ME interposed therebetween be calculated according to formula “b·Lref” (where “b” is a variable of 1 or larger that is larger than “a”), where “Lref” is the reference spacing. Therefore, the spacing L7between adjacent second demarcation parts327with a reticulation ME interposed therebetween is further greater than the spacing L6between adjacent second demarcation parts227with a reticulation ME interposed therebetween in Example 3 described above. Specifically, the ratio variable b, which defines the spacing L7between adjacent second demarcation parts327with a reticulation ME interposed therebetween, needs only be calculated according to formula (1) or (2) below (where “AR” is the target value of the opening ratio of the transparent antenna). That is, the ratio variable b is a variable that depends on the ratio variable a. This allows the opening area of the reticulations ME to be larger by the expansion (L7−L1) of the spacing L7between adjacent second demarcation parts327with a reticulation ME interposed therebetween than in Embodiment 3 described above. This allows the transparent antenna to have a higher opening ratio. Moreover, the opening area of the reticulations ME can be ensured as usual, for example, by adjusting the spacing L7between adjacent second demarcation parts327with a reticulation ME interposed therebetween to take on such a value as to compensate for a decrease in the opening area of the reticulations ME attributed to an increase in value of the ratio variable a, which defines the spacing L1between adjacent first demarcation parts326with a reticulation ME interposed therebetween.

The following describes Comparative Experiment 4, which was conducted to find out how the opening ratio of the transparent antenna thus configured varies according to the ratio variables a and b of the spacings L1and L7between demarcation parts326and between demarcation parts327. In addition to Comparative Example and Example 3 of Comparative Experiment 3 described above, Comparative Experiment 4 uses Example 4, which is a transparent antenna configured such that the spacing L7between adjacent second demarcation parts327with a reticulation ME interposed therebetween is defined by the ratio variable b that is larger than the ratio variable a defining the spacing L1between adjacent first demarcation parts326with a reticulation ME interposed therebetween, i.e. a transparent antenna described in the preceding paragraphs. In Comparative Experiment 4, the spacing L1between adjacent first demarcation parts326with a reticulation ME interposed therebetween in Example 4 takes on a value calculated according to formula “Lref/a” and the spacing L7between adjacent second demarcation parts327with a reticulation ME interposed therebetween in Example 4 takes on a value calculated according to formula “b·Lref”.FIG. 19shows the results of calculation of the opening ratio of each of the transparent antennas of Comparative Example and Example 4 with variations of this ratio variable a. It should be noted that the spacing L1between adjacent first demarcation parts326with a reticulation ME interposed therebetween in Example 4 is equal to the spacing between adjacent first demarcation parts with a reticulation interposed therebetween and the spacing between adjacent second demarcation parts with a reticulation interposed therebetween in Comparative Example. Further, the line widths W2and W5of the demarcation parts326and327of Example 4 are equal to the line width of each of the demarcation parts of Comparative Example.

InFIG. 19, the horizontal axis represents the ratio variable a (no unit of quantity required), and the vertical axis represents the opening ratio of each of the transparent antennas (no unit of quantity required), as inFIG. 16of Comparative Experiment 3. InFIG. 19, the solid line graph represents the experimental result of Example 4, the dashed-dotted line graph represents the experimental result of Example 3, and the dotted line graph represents the experimental result of Comparative Example. The opening ratio of the transparent antenna of Example 4 was calculated as follows: The opening ratio of the transparent antenna was calculated from formula “(L1−W5)(L7−W2)/L1·L7”, where “L1” is the spacing between adjacent first demarcation parts326with a reticulation ME interposed therebetween, “L7” is the spacing between adjacent second demarcation parts327with a reticulation ME interposed therebetween, “W5” is the line width of each first demarcation part326, and “W2” is the line width of each second demarcation part327. It should be noted that, in Comparative Experiment 4, formulas “W5=W2=Wref”, “L7=b·Lref>L1=Lref/a”, and “b>a” hold.

Here are the experimental results of Comparative Experiment 4. According toFIG. 19, the opening ratio of the transparent antenna of Example 4 is held substantially constant even with increase in ratio variable a. Therefore, the difference in opening ratio between the transparent antennas of Example 4 and the transparent antennas of Example 3 and Comparative Example tends to become greater with increase in ratio variable a. In Example 4, since the spacing L7between adjacent second demarcation parts327with a reticulation ME interposed therebetween is wider than the spacing L1between adjacent first demarcation parts326with a reticulation ME interposed therebetween, the opening ratio of the transparent antenna is higher by the difference between the spacings L1and L7. Moreover, it is preferable that the spacing L7between adjacent second demarcation parts327with a reticulation ME interposed therebetween be set by using, as the ratio variable b, a value calculated from formula (1) or (2) above. Doing so makes it possible to hold the opening ratio of the transparent antenna constant regardless of whether the ratio variable a is large or small, as indicated by the solid line graph inFIG. 19. All this makes it possible to ensure the opening ratio, i.e. light transmittance, of the transparent antenna as usual while keeping the wiring resistance sufficiently low.

According to the present embodiment, as described above, the spacing L1between adjacent first demarcation parts326is narrower than the spacing L7between adjacent second demarcation parts327. In this way, by making the spacing L1between adjacent first demarcation parts326narrower than the spacing L7between adjacent second demarcation parts327, the number of first demarcation parts326provided is made larger than the number of second demarcation parts327provided. This allows the per unit length area of the first extension part323comprising the plurality of first demarcation parts326to be larger than the per unit length area of the second extension part324comprising the plurality of second demarcation parts327. Moreover, by appropriately adjusting the spacing L7between adjacent second demarcation parts327, it is made possible to ensure the opening area of the reticulations ME as usual while maintaining the wiring resistance.

Embodiment 5 of the present invention is described with reference toFIG. 20 or 21. Embodiment 5 illustrates different planar shapes of reticulations ME and demarcation parts425from Embodiment 3 described above. It should be noted that a repeated description of structures, actions, and effects which are similar to those of Embodiment 3 described above is omitted.

As shown inFIGS. 20 and 21, an antenna wire421according to the present embodiment is formed by pattering a reticulated metal film having reticulations ME and demarcation parts425whose planar shapes are parallelograms. The demarcation parts425, which demarcate the reticulations ME, are constituted by first demarcation parts426extending along a direction inclined with respect to the direction of extension of the antenna wire421and second demarcation parts427extending along a direction orthogonal to the direction of extension of the antenna wire421, with the first demarcation parts426serving as the oblique sides of the parallelograms and the second demarcation parts427serving as the bases of the parallelograms. Whereas the first demarcation parts426have their planar shapes in a staggered zigzag manner, the second demarcation parts427have their planar shapes in a linear manner. As shown inFIG. 20, a short side part418S of the antenna wire421is configured such that the first demarcation parts426extend along a direction inclined with respect to both the X-axis and Y-axis directions (first and second directions), which are directions parallel to the side parts418S and418L, respectively, of the antenna wire421and the second demarcation parts427extend along the Y-axis direction (second direction), which is a direction orthogonal to the short side part418S. As shown inFIG. 21, a long side part418L of the antenna wire421is configured such that the first demarcation parts426extend along a direction inclined with respect to both the X-axis and Y-axis directions (first and second directions) and the second demarcation parts427extend along the X-axis direction (first direction), which is a direction orthogonal to the long side part418L.

Moreover, as shown inFIGS. 20 and 21, the antenna wire421is configured such that the length of each of the first demarcation parts426(i.e. the spacing between adjacent second demarcation parts427with a reticulation ME interposed therebetween) is longer (wider) than the length of each of the second demarcation parts427(i.e. the spacing between adjacent first demarcation parts426with a reticulation ME interposed therebetween). Therefore, whereas a reticulation ME defined by demarcation parts426and427in a short side part418S has a horizontally long parallelogramatic shape (FIG. 20), a reticulation ME defined by demarcation parts426and427in a long side part418L has a vertically long parallelogramatic shape (FIG. 21). In other words, since the length of each of the second demarcation parts427is narrower than the length of each of the first demarcation parts426, the number of first demarcation parts426that are had by a first extension part423is larger than the number of second demarcation parts427that are had by a second extension part424. This allows the per unit length area of the first extension part423comprising the plurality of first demarcation parts426to be larger than the per unit length area of the second extension part424comprising the plurality of second demarcation parts427.

According to the present embodiment, as described above, the antenna wire421has a planar shape forming a quadrangular ring and has a pair of short side parts418S extending parallel to a first direction and a pair of long side parts418L extending parallel to a second direction orthogonal to the first direction, the short side parts418S are each configured such that the first demarcation part426extends along a direction inclined with respect to the first and second directions and the second demarcation part427extends along the second direction, and the long side parts418L are each configured such that the first demarcation part426extends along a direction inclined with respect to the first and second directions and the second demarcation part427extends along the first direction. In this way, in each of the short side parts418S, of the antenna wire421having a planar shape forming a quadrangular ring, which extend parallel to the first direction, the per unit length area of the first extension part423comprising a plurality of the first demarcation parts426extending along a direction inclined with respect to the first and second directions is larger than the per unit length area of the second extension part424comprising a plurality of the second demarcation parts427extending along the second direction orthogonal to the first direction. On the other hand, in each of the long side parts418L, of the antenna wire421, which extend parallel to the second direction, the per unit length area of the first extension part423comprising a plurality of the first demarcation parts426extending along a direction inclined with respect to the first and second directions is larger than the per unit length area of the second extension part424comprising a plurality of the second demarcation parts427extending along the first direction. This makes it possible to achieve a reduction in wiring resistance while achieving sufficient light transmittance.

Embodiment 6 of the present invention is described with reference toFIG. 22 or 23. Embodiment 6 illustrates different planar shapes of reticulations ME and demarcation parts525from Embodiment 5 described above. It should be noted that a repeated description of structures, actions, and effects which are similar to those of Embodiment 5 described above is omitted.

As shown inFIGS. 22 and 23, an antenna wire521according to the present embodiment is configured such that the planar shapes of first demarcation parts526of demarcation parts525demarcating reticulations ME are curved. Specifically, each of the first demarcation parts526extends in such a form as to intersect with both the X-axis and Y-axis directions (first and second directions), which are directions parallel to side parts518S and518L, respectively, of the antenna wire521, and has a planar shape forming a sinusoidal waveform (i.e. a waveform that undergoes a periodic change). Moreover, the antenna wire521is configured such that the length of each of the first demarcation part526(i.e. the spacing between adjacent second demarcation parts527with a reticulation ME interposed therebetween) is longer (wider) than the length of each of the second demarcation parts527(i.e. the spacing between adjacent first demarcation parts526with a reticulation ME interposed therebetween), whereby the number of first demarcation parts526that are had by a first extension part523is larger than the number of second demarcation parts527that are had by a second extension part524.

According to the present embodiment, as described above, the antenna wire521has a planar shape forming a quadrangular ring and has a pair of short side parts518S extending parallel to a first direction and a pair of long side parts518L extending parallel to a second direction orthogonal to the first direction, the short side parts518S are each configured such that the first demarcation part526extends in such a form as to intersect with the first direction and the second direction and has a planar shape forming a curve and the second demarcation part527extends along the second direction, and the long side parts518L are each configured such that the first demarcation part526extends in such a form as to intersect with the first direction and the second direction and has a planar shape forming a curve and the second demarcation part527extends along the first direction. In this way, in each of the short side parts518S, of the antenna wire521having a planar shape forming a quadrangular ring, which extend parallel to the first direction, the per unit length area of the first extension part523comprising a plurality of the first demarcation parts526each extending in such a form as to intersect with the first direction and the second direction and having a planar shape forming a curve is larger than the per unit length area of the second extension part524comprising a plurality of the second demarcation parts527extending along the second direction orthogonal to the first direction. On the other hand, in each of the long side parts518L, of the antenna wire521, which extend parallel to the second direction, the per unit length area of the first extension part523comprising a plurality of the first demarcation parts526each extending in such a form as to intersect with the first direction and the second direction and having a planar shape forming a curve is larger than the per unit length area of the second extension part524comprising a plurality of the second demarcation parts527extending along the first direction. This makes it possible to achieve a reduction in wiring resistance while achieving sufficient light transmittance.

Embodiment 7 of the present invention is described with reference toFIG. 24 or 25. Embodiment 7 illustrates a different patterning of a reticulated metal film constituting a transparent antenna617from Embodiment 1 described above. It should be noted that a repeated description of structures, actions, and effects which are similar to those of Embodiment 1 described above is omitted.

As shown inFIGS. 24 and 25, the transparent antenna617according to the present embodiment is configured such that an antenna wire621has a first extension part34extending along a direction inclined with respect to both the direction of extension of the antenna wire621and a direction orthogonal thereto and a second extension part35connected to the first extension part34by extending along a direction inclined with respect to both the direction of extension and the direction orthogonal thereto and intersecting with the first extension part34and that each of the first and second extension parts34and35is inclined at a smaller angle with respect to the direction of extension than with respect to the direction orthogonal to the direction of extension. The angle of inclination of the first extension part34with respect to the direction of extension of the antenna wire621(direction orthogonal to the direction of extension) is equal to the angle of inclination of the second extension part35with respect to the direction of extension of the antenna wire621(direction orthogonal to the direction of extension). The first and second extension parts34and35connected to each other are configured to form linear shapes with each other and demarcate reticulations ME whose planar shapes are flat rhombuses.

As shown inFIG. 24, a short side part618S of the antenna wire621is configured such that the angle of inclination of the first extension part34and second extension part35with respect to the X-axis direction (first direction), which is a direction (direction of extension) parallel to the short side part618S, is relatively smaller than the angle of inclination of the first extension part34and the second extension part35with respect to the Y-axis direction (second direction), which is a direction orthogonal to the X-direction. Therefore, the planar shapes of the reticulations ME that the short side part618S has are horizontally long rhombuses. As shown inFIG. 25, a long side part618L of the antenna wire621is configured such that the angle of inclination of the first extension part34and the second extension part35with respect to the Y-axis direction (first direction), which is a direction (direction of extension) parallel to the long side part618L, is relatively smaller than the angle of inclination of the first extension part34and the second extension part35with respect to the X-axis direction (second direction), which is a direction orthogonal to the Y-axis direction. Therefore, the planar shapes of the reticulations ME that the long side part618L has are vertically long rhombuses.

Incidentally, in the first extension part34extending along a direction inclined with respect to both the direction of extension of the antenna wire621and a direction orthogonal thereto and the second extension part35extending in such a form as to be inclined with respect to both the direction of extension of the antenna wire621and the direction orthogonal thereto and intersect with the direction of extension of the first extension part34, the path length in the direction of extension of the antenna wire621tends to become longer and the path length in the direction orthogonal to the direction of extension of the antenna wire621tends to become shorter as the angle of inclination with respect to the direction of extension of the antenna wire621becomes larger and the angle of inclination with respect to the direction orthogonal to the direction of extension of the antenna wire621becomes smaller, and the path length in the direction of extension of the antenna wire621tends to become shorter and the path length in the direction orthogonal to the direction of extension of the antenna wire621tends to become longer as the angle of inclination with respect to the direction of extension of the antenna wire621becomes smaller and the angle of inclination with respect to the direction orthogonal to the direction of extension of the antenna wire621becomes larger. Moreover, since, as described above, the antenna wire621is configured such that each of the first and second extension parts34and35is inclined at a smaller angle with respect to the direction of extension of the antenna wire621than with respect to the direction orthogonal to the direction of extension of the antenna wire621, the path length in the direction of extension of the antenna wire621becomes shorter. This makes it possible to efficiently lower the wiring resistance while sufficiently securing the opening area of the reticulations ME. This in turn makes it possible to achieve a reduction in wiring resistance while achieving sufficient light transmittance.

As described above, the present embodiment includes an antenna wire621, formed by a reticulated metal film in a shape of a ring, which generates a magnetic field on a center side thereof. The antenna wire621has a first extension part34extending along a direction inclined with respect to both a direction of extension of the antenna wire and a direction orthogonal thereto and a second extension part35extending along a direction inclined with respect to both the direction of extension and the direction orthogonal thereto and intersecting with the first extension part34. The antenna wire621is configured such that each of the first and second extension parts34and35is inclined at a smaller angle with respect to the direction of extension than with respect to the direction orthogonal to the direction of extension.

In this way, the flow of an electric current through the ring-shaped antenna wire621causes a magnetic field to be generated on the center side of the antenna wire621by an electromagnetic induction effect. The antenna wire621is formed by the reticulated metal film, which has reticulations ME through which light is transmitted, whereby the translucency of the transparent antenna is secured. The wiring resistance of the antenna wire621tends to become lower as the opening area of the reticulations ME in the metal film becomes smaller and the area of the metal film becomes larger, and tends to become higher as the opening area of the reticulations ME in the metal film becomes larger and the area of the metal film becomes smaller. Note here that, in the first extension part34extending along a direction inclined with respect to both the direction of extension of the antenna wire621and a direction orthogonal thereto and the second extension part35extending along a direction inclined with respect to both the direction of extension of the antenna wire621and the direction orthogonal thereto and intersecting with the direction of extension of the first extension part34, the path length in the direction of extension of the antenna wire621tends to become longer and the path length in the direction orthogonal to the direction of extension of the antenna wire621tends to become shorter as the angle of inclination with respect to the direction of extension of the antenna wire621becomes larger and the angle of inclination with respect to the direction orthogonal to the direction of extension of the antenna wire621becomes smaller, and the path length in the direction of extension of the antenna wire621tends to become shorter and the path length in the direction orthogonal to the direction of extension of the antenna wire621tends to become longer as the angle of inclination with respect to the direction of extension of the antenna wire621becomes smaller and the angle of inclination with respect to the direction orthogonal to the direction of extension of the antenna wire621becomes larger.

Moreover, since the antenna wire621is configured such that each of the first and second extension parts34and35is inclined at a smaller angle with respect to the direction of extension of the antenna wire621than with respect to the direction orthogonal to the direction of extension of the antenna wire621, the path length in the direction of extension of the antenna wire621becomes shorter. This makes it possible to efficiently lower the wiring resistance while sufficiently securing the opening area of the reticulations ME. This in turn makes it possible to achieve a reduction in wiring resistance while achieving sufficient light transmittance.

Embodiment 8 of the present invention is described with reference toFIG. 26 or 27. Embodiment 8 illustrates different planar shapes of first and second extension parts734and735from Embodiment 7 described above. It should be noted that a repeated description of structures, actions, and effects which are similar to those of Embodiment 7 described above is omitted.

As shown inFIGS. 26 and 27, an antenna wire721according to the present embodiment is configured such that the planar shapes of first and second extension parts734and735constituting long and short side parts718L and718S are both curved.

Embodiment 9 of the present invention is described with reference toFIG. 28. Embodiment 9 illustrates a different placement of a transparent antenna817from Embodiment 1 described above. It should be noted that a repeated description of structures, actions, and effects which are similar to those of Embodiment 1 described above is omitted.

As shown inFIG. 28, the transparent antenna817according to the present embodiment is placed such that the long and short side directions of an antenna body part818and the direction of extension of lead wiring parts819are each inclined with respect to both the X-axis and Y-axis directions, which are the long and short side directions of a liquid crystal panel (not illustrated). The transparent antenna817is constituted by a reticulated metal film configured such that, of demarcation parts demarcating reticulations, first demarcation parts extend along the direction of extension of antenna wires821and second demarcation parts extend along a direction orthogonal to the antenna wires821. The direction of extension of the antenna wires821and the direction orthogonal thereto are each inclined with respect to both the X-axis and Y-axis directions. A large number of the reticulations had by the transparent antenna817are arranged in a matrix along the direction of extension of the antenna wires821and the direction orthogonal thereto, and the directions of arrangement are inclined with respect to both the X-axis and Y-axis directions. Meanwhile, the liquid crystal panel has a large number of pixels arranged in a matrix along the long and short side directions thereof, and the directions of arrangement are parallel to the X-axis direction and the Y-axis direction. Therefore, in this placement, the direction of arrangement of the reticulations had by the transparent antenna817and the direction of arrangement of the pixels had by the liquid crystal panel are inclined with respect to each other. This makes it difficult for interference to occur between the pixels of the liquid crystal panel and the reticulations of the transparent antenna817and therefore makes it difficult for interference fringes called moiré to appear on an image displayed on the liquid crystal panel, thereby achieving high display quality.

According to the present embodiment, as described above, the liquid crystal panel has a large number of pixels arranged in a matrix in a plane of a display surface of the liquid crystal panel, the transparent antenna817has a large number of reticulations arranged in a matrix, and a direction of arrangement of the reticulations is inclined with respect to a direction of arrangement of the pixels. In this way, the inclination of the direction of arrangement of the reticulations of the transparent antenna817with respect to the direction of arrangement of the pixels in the liquid crystal panel reduces the appearance of interference fringes called moiré, thereby bringing about improvement in display quality.

Other Embodiments

The present invention is not limited to the embodiments described above with reference to the foregoing descriptions and drawings. For example, the following embodiments are encompassed in the technical scope of the present invention:

(1) Besides the embodiments described above (excluding Embodiments 7 and 8), changes can be made as appropriate to specific numerical values, ratios, and the like such as the line widths of the first and second demarcation parts, the spacing between adjacent first demarcation parts with a reticulation interposed therebetween (i.e. the length of each of the second demarcation parts), and the spacing between adjacent second demarcation parts with a reticulation interposed therebetween (i.e. the length of each of the first demarcation parts).

(2) Besides Embodiments 7 and 8 described above, changes can be made as appropriate to specific numerical values, ratios, and the like such as the line widths of the first and second extension parts, the spacing between adjacent first extension parts, and the spacing between adjacent second extension parts.

(3) While Embodiment 2 described above illustrates a case where the spacing between adjacent second demarcation parts with a reticulation interposed therebetween (i.e. the length of each of the first demarcation parts) is wider (longer) than the spacing between adjacent first demarcation parts with a reticulation interposed therebetween (i.e. the length of each of the second demarcation parts), the former can be narrower (shorter) than the latter. In that case, a rise in wiring resistance can be suppressed simply by widening the difference between the line width of each of the first demarcation parts and the line width of each of the second demarcation parts.

(4) While Embodiment 2 described above illustrates a case where the line width of each of the first demarcation parts is wider than the line width of each of the second demarcation parts, the former can be narrower than the latter. In that case, a rise in wiring resistance can be suppressed simply by widening the difference between the spacing between adjacent second demarcation parts with a reticulation interposed therebetween (i.e. the length of each of the first demarcation parts) and the spacing between adjacent first demarcation parts with a reticulation interposed therebetween (i.e. the length of each of the second demarcation parts).

(5) While each of Embodiments 3 to 6 described above illustrates a case where the number of second demarcation parts is made smaller than the number of first demarcation parts by making the spacing between adjacent second demarcation parts with a reticulation interposed therebetween (i.e. the length of each of the first demarcation parts) wider (longer) than the spacing between adjacent first demarcation parts with a reticulation interposed therebetween (i.e. the length of each of the second demarcation parts), the number of second demarcation parts can be made even smaller by arranging the second demarcation parts in a staggered manner in addition to making the spacing between adjacent second demarcation parts with a reticulation interposed therebetween (i.e. the length of each of the first demarcation parts) wider (longer) than the spacing between adjacent first demarcation parts with a reticulation interposed therebetween (i.e. the length of each of the second demarcation parts). Alternatively, the number of second demarcation parts can be made smaller than the number of first demarcation parts by making the spacing between adjacent first demarcation parts with a reticulation interposed therebetween and the spacing between adjacent first demarcation parts with a reticulation interposed therebetween equal and then arranging the second demarcation parts in a staggered manner.

(6) While each of the embodiments described above illustrates a case where slits forming a grid are formed in the antenna-free region of the reticulated metal film constituting the transparent antenna, it is alternatively possible to employ a configuration in which no such slits are formed in the antenna-free region.

(7) While each of the embodiments described above illustrates a case where the transparent antenna is placed near the position of a lower edge of the liquid crystal panel in the Y-axis direction, it is possible to appropriately change the specific placement of the transparent antenna in the X-axis direction and the Y-axis direction in the plane of the liquid crystal panel. For example, the transparent antenna may be placed near a middle or upper position in the Y-axis direction in the plane of the liquid crystal panel, or may be placed in a middle position or the like in the X-axis direction.

(8) While each of the embodiments described above illustrates a case where the planar shape of the antenna body part is a vertically long quadrangular shape, the planar shape of the antenna body part may alternatively be a vertically long quadrangular shape or a square. Apart from these shapes, the planar shape of the antenna body part may be a circle, an ellipse, or the like.

(9) While each of the embodiments described above illustrates a case where the lead wiring part is configured to extend from the antenna body part downward in the Y-axis direction in the liquid crystal display device, it is alternatively possible to configure the lead wiring part to extend from the antenna body part upward in the Y-axis direction in the liquid crystal display device. Furthermore, it is alternatively possible to configure the lead wiring part to extend from the antenna body part either leftward or rightward in the X-axis direction in the liquid crystal display device. In that case, it is preferable that the placement of the antenna body part be rotated 90 degrees.

(10) While each of the embodiments described above illustrates an antenna body part constituted by four antenna wires, it is possible to appropriately change the number of antenna wires (number of turns) that constitute the antenna body part. In the case of a change in the number of antenna wires, it is only necessary to appropriately change the number of lead wiring parts and the number of antenna connection wiring parts accordingly.

(11) While each of the embodiments described above illustrates a case where the transparent antenna has a symmetrical shape, the transparent antenna may alternatively have an asymmetrical shape.

(12) While each of the embodiments described above illustrates an antenna body part formed in the shape of a closed ring surrounding the magnetic field generation region, the present invention is also applicable to an antenna body part formed in the shape of an open ring so that each of the antenna wires has its two ends opened.

(13) While each of the embodiments described above illustrates a case where the planar shape of the liquid crystal panel is a horizontally long quadrangular shape, the planar shape of the liquid crystal panel may alternatively be a vertically long quadrangular shape or a square. Apart from these shapes, the planar shape of the liquid crystal panel may be a circle, an ellipse, or the like; furthermore, the planar shape of the outer edges of the liquid crystal panel may be formed in the shape of a combination of straight and curved lines.

(14) The technical matters described in the embodiments described above may be appropriately combined.

(15) While each of the embodiments described above illustrates a liquid crystal display device including a liquid crystal panel having a screen size of 30-something inches to 50-something inches, the present invention is also applicable to a liquid crystal display device including a liquid crystal panel having a screen size of 30 inches or smaller or a screen size of 60 inches or larger.

(16) While each of the embodiments described above illustrates a liquid crystal display device that is used in an electronic device such as an information display, an electronic blackboard, and a television receiving apparatus, the present invention is also applicable to a liquid crystal display device that is used in any of other types of electronic device such as PC monitors (including desktop PC monitors and laptop PC monitors), tablet terminals, phablet terminals, smartphones, mobile phones, and mobile game machines.

(17) While each of the embodiments described above illustrates a liquid crystal panel (VA-mode liquid crystal panel) configured such that the array substrate is provided with pixel electrodes, that the CF substrate is provided with a common electrode, and that the pixel electrodes and the common electrode overlap each other with a liquid crystal layer sandwiched therebetween, the present invention is also applicable to a liquid crystal display device including a liquid crystal panel (FFS-mode liquid crystal panel) configured such that the array substrate is provided with both pixel electrodes and a common electrode and the pixel electrodes and the common electrode overlap each other with an insulating film sandwiched therebetween. The present invention is also applicable to a liquid crystal display device including a so-called IPS-mode liquid crystal panel.

(18) While each of the embodiments described above illustrates a case where the color filter of the liquid crystal panel is constituted by three colors of red, green, and blue, the present invention is also applicable to a liquid crystal panel including a color filter constituted by four colors by adding a colored portion of yellow to the colored portions of red, green, and blue.

(19) While each of the embodiments described above illustrates a transmissive liquid crystal display device including a backlight device serving as an external light source, the present invention is also applicable to a reflective liquid crystal display device that performs a display by means of outside light. In that case, the backlight device may be omitted. Further, the present invention is also applicable to a semi-transmissive liquid crystal display device.

(20) While each of the embodiments described above uses TFTs as the switching elements of the liquid crystal panel, it is also applicable to a liquid crystal display device including a liquid crystal panel including switching elements other than TFTs (e.g. thin-film diodes (TFDs)). It is also applicable to a liquid crystal display device including a liquid crystal panel that performs a black-and-white display as well as a liquid crystal display device including a liquid crystal panel that performs a color display.

(21) While each of the embodiments described above illustrates a liquid crystal display device including a liquid crystal panel as a display panel, the present invention is also applicable to a display device including any of other types of display panel (such as PDPs (plasma display panels), organic EL panels, and EPDs (electrophoretic display panels)). In these cases, the backlight device may be omitted. Further, the present invention is also applicable to a display device including a MEMS display panel.

(22) While each of the embodiments described above illustrates a case where the per unit length areas of the corner-part first and second extension parts constituting a corner part of the transparent antenna are equal to each other, the corner-part first and second extension parts may alternatively be configured to be different in size of per unit length area. Further, the per unit length area of the corner-part first extension part in the corner part may be equal to or larger than the per unit length area of the first extension part in each side part. Similarly, the per unit length area of the corner-part second extension part in the corner part may be equal to or smaller than the per unit length area of the second extension part in each side part.

REFERENCE SIGNS LIST