Antenna and wireless terminal equipped therewith

Abstract

A transparent antenna is used in a wireless terminal (100) provided with: an imaging element having a plurality of pixels (21) arranged in an array; and, a camera lens (22) disposed above the imaging element. The transparent antenna comprises an antenna pattern (31) that is included in an antenna base material (32) provided above the camera lens (22).

Description

Technical Field

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[0001] The present disclosure relates to an antenna and a wireless terminal provided with the same.

Background Art

[0002] Wireless terminals having a wireless communication function, such as smartphones, are provided with an antenna in order to acquire external information and transmit information to the outside. For example, in the touch panel module (wireless terminal) of Patent Document 1, an antenna pattern exists in a region extending from an end portion of a cover glass or a cover film.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] <A As described above, in the touch panel module of Patent Document 1, since the antenna pattern exists in a region extending from an end portion of the cover glass or the cover film, when a user operates the touch panel module or makes a call, the user's hand or ear may touch the antenna pattern. When the user's hand or ear contacts the antenna pattern, the antenna sensitivity may deteriorate. In order to stabilize communication, it is also conceivable to use a plurality of antennas in combination, but the installation location of the antenna in the wireless terminal is limited.

[0005] The present disclosure has been made in view of such points, and an object thereof is to provide an antenna that enables stable communication while securing an installation location for the antenna.

Means for Solving the Problems

[0006] To achieve the above objective, a transparent antenna according to one embodiment of the present disclosure is a transparent antenna used in a wireless terminal comprising an image sensor having a plurality of pixels arranged in an array and a camera lens disposed above the image sensor, wherein the transparent antenna consists of an antenna pattern contained in an antenna substrate provided above the camera lens. [Effects of the Invention]

[0007] According to this disclosure, stable communication can be achieved while securing a location for antenna installation. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is an enlarged view of the area around the camera in a wireless terminal according to an embodiment of this disclosure. [Figure 2] Figure 2 is a cross-sectional view taken along line II in Figure 1. [Figure 3] Figure 3 is a cross-sectional view taken along line II-II in Figure 1. [Figure 4] Figure 4 is a magnified view of part III of Figure 1. [Figure 5] Figure 5 shows the arrangement relationship between pixels and metal wires in a wireless terminal according to an embodiment of this disclosure, as viewed from a planar perspective. [Figure 6] Figure 6 shows images captured by a wireless terminal according to an embodiment of this disclosure and a wireless terminal without an antenna unit on the top of the camera unit. [Modes for carrying out the invention]

[0009] Embodiments of the present disclosure will be described in detail below with reference to the drawings. The following description of embodiments is illustrative in nature and is not intended to limit the present disclosure, its applications, or its uses.

[0010] Figure 1 shows the area around the camera unit 2 of a wireless terminal 100 according to an embodiment of this disclosure. This wireless terminal 100 has at least a communication function with an external device and a camera function for taking images of the outside. This wireless terminal 100 is a wireless terminal having wireless communication capabilities, such as a smartphone, mobile phone, tablet, wristwatch-type electronic device, digital camera, video camera, or pen-type microscope.

[0011] As shown in Figures 1 and 2, the wireless terminal 100 comprises a main body 1, a camera unit 2, an antenna unit 3, and a cover glass 4. In the following description, the side where the main body 1 is located will be referred to as the "lower side" of the wireless terminal 100, and the side on the opposite side where the cover glass 4 is located will be referred to as the "upper side" of the wireless terminal 100. The positional relationships of the elements constituting the wireless terminal 100 will be defined accordingly. Such positional relationships are independent of the actual orientation of the wireless terminal 100.

[0012] (Camera Club) The camera unit 2 comprises multiple pixels 21 (image sensors) and a camera lens 22. Although not shown in Figures 1 and 2, the multiple pixels 21 are arranged in an array along the top surface of the main unit 1. The camera lens 22 is positioned above these multiple pixels 21. The multiple pixels 21 are connected to a drive circuit (not shown) configured in the main unit 1, and receive signals from the drive circuit to output pixel signals. The wireless terminal 100 generates (captures) an external image based on the pixel signals output from each pixel 21.

[0013] (Antenna section) The antenna unit 3 is an antenna module, such as a patch antenna, that transmits and receives signals with an external device. The antenna unit 3 comprises an antenna pattern 31 (transparent antenna) and an antenna substrate 32. In the following explanation, we will use the case where the antenna pattern 31 is a patch antenna and the wireless terminal 100 is a smartphone as an example.

[0014] As shown in FIG. 1, in this embodiment, four antenna patterns 31 arranged in a 2×2 array are formed in the antenna unit 3. This antenna pattern 31 is formed within the antenna substrate 32.

[0015] As shown in FIG. 2, each antenna pattern 31 is connected to an RFM (Radio Frequency Module) substrate 33 formed in the main body unit 1. The antenna unit 3 receives an RF signal from an external device via the antenna pattern 31. The antenna unit 3 outputs the received RF signal to an RF circuit (not shown) configured in the main body unit 1 via the RFM substrate 33. Also, the antenna unit 3 receives a transmission signal output from the RF circuit via the RFM substrate 33. The antenna unit 3 transmits the received transmission signal to an external device via the antenna pattern 31.

[0016] (Cover glass) The cover glass 4 is disposed on the upper surface side of the camera lens 22 so as to cover the camera lens 22. The cover glass 4 is formed of, for example, a glass material. Also, the cover glass 4 is formed, for example, in a range of about 10 mm to 30 mm in diameter.

[0017] As shown in FIG. 1, the cover glass 4 is arranged to have substantially the same size as the camera lens 22 and overlap the camera lens 22 when viewed in plan view. Thereby, when viewed in plan view, the entire camera lens 22 is covered by the cover glass 4, so that the influence on the imaging of the camera unit 2 can be suppressed.

[0018] As shown in FIG. 2, the cover glass 4 is arranged with a gap S from the main body unit 1 (camera lens 22). The antenna pattern 31 is disposed on the lower surface of the cover glass 4. By forming the antenna pattern 31 on the lower surface of the cover glass 4, the antenna pattern 31 can be arranged separated from the main body unit 1, so that the antenna performance can be improved.

[0019] (Antenna substrate) The antenna substrate 32 is formed in a film shape. As shown in FIG. 3, it is disposed on the lower surface of the cover glass 4. The antenna substrate 32 includes a transparent substrate 34 (film substrate). The transparent substrate 34 is formed of a material such as a transparent resin film like PET (polyethylene terephthalate), COP (cyclic olefin polymer), or transparent glass.

[0020] An antenna pattern 31 is formed between the cover glass 4 and the transparent substrate 34. Note that the antenna pattern 31 (specifically, the metal fine wire 311 described later) may be embedded in the transparent substrate 34. In this case, the antenna pattern 31 is formed in a groove portion formed on the surface of the transparent substrate 34. Note that the groove portion may be provided in a thin film resin portion provided over the surface of the transparent substrate 34. That is, the transparent substrate 34 includes those configured to include a plurality of layers.

[0021] As shown in FIG. 1, the antenna substrate 32 is formed to have approximately the same size as the cover glass 4 when viewed in plan view. Thereby, reflection at the end portion of the antenna substrate 32 can be suppressed, and thus the influence on the imaging of the camera unit 2 can be suppressed. Note that the same effect can be obtained even if the antenna substrate 32 has a size equal to or larger than that of the cover glass 4.

[0022] (Antenna Pattern) As shown in Figure 1, the antenna pattern 31 is formed in the shape of a rectangular sheet in plan view. The antenna section 3 is designed so that the width W in the X direction and the width L in the Y direction are each equal to the wavelength λ / 2 at the design frequency. For example, in the 28GHz frequency band, which is the frequency band for 5G (fifth-generation mobile communication system), the widths W and L are formed to approximately 5.35 mm in a vacuum. When the antenna pattern 31 is placed on a transparent substrate 34, the widths W and L are shortened by the dielectric constant of the transparent substrate 34. For example, if the transparent substrate 34 is PET (polyethylene terephthalate) with a thickness of 100 μm, the widths W and L can be formed to approximately 2.9 mm, which is smaller than 5.35 mm, and can be used effectively in the 28GHz frequency band. If the transparent substrate 34 is COP (cycloolefin polymer) with a thickness of 100 μm, the widths W and L can be formed to approximately 3.3 mm, which is smaller than 5.35 mm, and can be used effectively in the 28GHz frequency band. Therefore, it becomes possible to position the antenna unit 3 so that it overlaps with the camera unit 2 in a plan view.

[0023] As shown in Figure 4, the antenna pattern 31 includes a mesh pattern 312. In this embodiment, the mesh pattern 312 is formed in a mesh-like structure by conductive metal wires 311, 311, ... intersecting each other and being arranged at equal intervals. Note that the metal wires 311, 311, ... do not necessarily have to be arranged at equal intervals.

[0024] Furthermore, the metal wire 311 is formed such that the width A is, for example, 2.5 μm or less.

[0025] Each metal wire 311 is connected to a connector 313. Each metal wire 311 extends diagonally with respect to the X-axis and Y-axis directions, respectively. Specifically, each metal wire 311 intersects with the connector 313 such that its direction of length diagonally crosses the connector 313. The connection points between the metal wires 311, 311, ... and the connector 313 are spaced apart from each other in the longitudinal direction (X-axis direction) of the connector 313. Each metal wire 311 is connected to the RFM substrate 33 via this connector 313. Note that this connector 313 is not necessarily required. In this case, each metal wire 311 is connected to the RFM substrate 33 without using the connector 313.

[0026] The mesh pattern 312 has a network structure in which multiple cells 314, 314, ... made of thin wires are arranged regularly. Each cell 314 is formed to be the same size as the others and is a square with two diagonals (not shown) of equal length. The shape of each cell 314 may be a parallelogram or a rhombus.

[0027] As described above, the antenna section 3 is composed of an antenna pattern 31 made up of multiple metal wires 311 and a transparent substrate 34, and therefore has a transmittance of a predetermined value or higher (for example, 80% or more). As a result, light can pass through the antenna section 3, and thus the influence on imaging by the camera section 2 can be suppressed.

[0028] As described above, the width A of the metal wire 311 is 2.5 μm or less. Also, the pitch B of the pixels 21 is approximately 1.4 μm. Therefore, the width A of the metal wire 311 and the pitch B of the pixels 21 are approximately the same (see Figure 5). This makes it possible to suppress the influence on imaging by the camera unit 2. Furthermore, by setting the spacing between the metal wires 311 to be larger than the pitch B of the pixels 21, the influence on imaging by the camera unit 2 can be further suppressed.

[0029] Furthermore, the antenna pattern 31 is positioned below the distance from the multiple pixels 21 to the shortest imaging distance of the camera unit 2. The shortest imaging distance refers to the distance from the subject to the multiple pixels 21 when the camera lens 22 can focus on the subject. In other words, by positioning the antenna pattern 31 below the distance from the multiple pixels 21 to the shortest imaging distance of the camera unit 2, the thin metal wires 311 that make up the antenna pattern 31 will not be captured in the image. This reduces the impact on the image capture of the camera unit 2.

[0030] Figure 6(a) shows an image captured by the camera unit 2 when the antenna unit 3 is attached to the top of the camera unit 2, and Figure 6(b) shows an image captured by the camera unit 2 when the antenna unit 3 is not attached to the top of the camera unit 2. As shown in Figures 6(a) and (b), it can be seen that there is almost no difference in image quality of the images captured by the camera unit 2 even when the antenna unit 3 is attached to the top of the camera unit 2.

[0031] [Effects of the Embodiment] As described above, in the wireless terminal 100, the antenna unit 3, which includes the antenna pattern 31, is positioned above the camera lens 22. This ensures that there is space for the antenna to be installed. In addition, the camera lens 22 is positioned in a location that is difficult for the user's fingers or hands to touch in order to capture images of the outside. By positioning the antenna unit 3 above the camera lens 22, it is possible to prevent the user's fingers or hands from touching the antenna pattern 31, thereby enabling stable communication.

[0032] Furthermore, the antenna section 3 has a transmittance of a predetermined value or higher. This allows light to pass through the antenna section 3, thereby suppressing the impact on image capture by the camera section 2.

[0033] Furthermore, the antenna pattern 31 is composed of multiple thin metal wires 311. This allows light to pass through the antenna pattern 31, thereby suppressing the influence on imaging by the camera unit 2.

[0034] Furthermore, the width A of the metal wire 311 is approximately the same as the pitch B of the pixels 21. This helps to suppress the influence on image capture by the camera unit 2.

[0035] Furthermore, the antenna unit 3 is positioned below the position from the multiple pixels 21 to the camera unit 2 (multiple pixels 21) at the shortest imaging distance. As a result, the thin metal wires 311 that make up the antenna pattern 31 are not captured in the image, thus suppressing the impact on the camera unit 2's image capture.

[0036] Furthermore, the cover glass 4 is positioned on the upper side of the camera lens 22 so as to cover the camera lens 22. The antenna unit 3 is positioned on the lower side of the cover glass 4. This allows the antenna pattern 31 to be positioned at a distance from the main body 1 of the wireless terminal 100, thereby improving antenna performance.

[0037] Furthermore, the antenna substrate 32 is at least the same size as the cover glass 4 when viewed from above. This suppresses reflection at the edges of the antenna substrate 32, thereby minimizing the impact on imaging by the camera unit 2.

[0038] Furthermore, the cover glass 4 is larger than the camera lens 22 when viewed from above. As a result, the entire camera lens 22 is covered by the cover glass 4 when viewed from above, thus minimizing the impact on image capture by the camera unit 2.

[0039] Furthermore, the antenna pattern 31 supports frequency bands of 5G and above, and when viewed from above, the widths W and L of the antenna pattern 31 can be made smaller than the dimensions of the camera lens 22, so the antenna pattern 31 can be positioned so as to overlap the top of the camera unit 2.

[0040] The 5G frequency band is 3.7GHz to 39GHz, and in a patch antenna, the widths W and L of the antenna pattern 31 are formed to be approximately 41.6mm to 3.8mm in a vacuum. When the antenna pattern 31 is placed on a transparent substrate 34, the widths W and L are shortened depending on the dielectric constant of the transparent substrate 34. For example, if the transparent substrate 34 is PET (polyethylene terephthalate) with a thickness of 100μm, it can be formed to be approximately 22.5mm to 2.1mm. The size of the cover glass can be appropriately set according to the widths W and L of each antenna pattern 31. Furthermore, the shape of the cover glass is not limited to a circle; for example, it may be a square, polygon, or ellipse.

[0041] Furthermore, the antenna section 3 has two or more antenna patterns 31. This improves antenna sensitivity.

[0042] [Other embodiments] In the above embodiment, the antenna pattern 31 is composed of a plurality of thin metal wires 311, but is not limited to this. The antenna pattern 31 may be composed of a metal plate made of a transparent metal such as ITO (Indium Tin Oxide) or PEDOT. The above-described effects can be obtained by composing the antenna pattern 31 of a transparent metal, but the above embodiment is preferred because composing the antenna pattern 31 of thin metal wires 311 results in a lower resistance value and reduces antenna loss.

[0043] Furthermore, although the above embodiment was described using the example that the antenna section 3 (antenna pattern 31) is a patch antenna, it is not limited to this, and other types of antennas may be used. For example, the antenna section 3 may be a dipole antenna or a monopole antenna. Even in this case, if the antenna pattern is made of fine metal wires, the same effects as in the above embodiment can be obtained. For example, in the 5G frequency band, a dipole antenna is designed so that the conductor is approximately λ / 2 = 41.6 mm to 3.8 mm in vacuum. When the antenna pattern 31 is placed on a transparent substrate 34, the widths W and L are shortened depending on the dielectric constant of the transparent substrate 34. For example, if the transparent substrate 34 is PET (polyethylene terephthalate) with a thickness of 100 μm, it can be formed to approximately 35.5 mm to 2.7 mm. Also, for example, in the 5G frequency band, a monopole antenna is designed so that the conductor is approximately λ / 4 = 20.8 mm to 1.9 mm in vacuum. When arranging the antenna pattern 31 on a transparent substrate 34, the widths W and L are shortened depending on the dielectric constant of the transparent substrate 34. For example, if the transparent substrate 34 is PET (polyethylene terephthalate) with a thickness of 100 μm, it can be formed to a width of 17.7 mm to 1.4 mm, and the size of the cover glass on which the antenna pattern 31 is arranged can be appropriately set according to the widths W and L of each antenna pattern 31. The shape of the cover glass can also be appropriately determined, such as a circle, square, polygon, or ellipse.

[0044] Furthermore, in the above embodiment, the antenna pattern 31 is formed in the shape of a rectangular sheet in plan view, but the shape of the antenna pattern 31 is not limited to this. For example, if the antenna section 3 is a dipole antenna, the shape of the antenna pattern 31 may be pole-shaped. In other words, the shape of the antenna pattern 31 may be suitable depending on the type of antenna used in the antenna section 3.

[0045] Furthermore, in the above embodiment, the multiple antenna patterns 31 are arranged in a 2x2 array, but the arrangement of the multiple antenna patterns 31 is not limited to this. Also, the number of antenna patterns 31 is not limited to four. [Industrial applicability]

[0046] The wireless terminals related to this disclosure can be used in various industrial applications, such as smartphones, mobile phones, tablets, smartwatches, digital cameras, video cameras, and pen-type microscopes. [Explanation of Symbols]

[0047] 100: Wireless terminal 1: Main body 2: Camera Department 21: Pixels 22: Camera lens 3: Antenna section 31: Antenna pattern (transparent antenna) 311: Fine metal wire 312: Mesh Pattern 313: Connection terminal 314: Cell 32: Antenna substrate 33:RFM base material 34: Transparent substrate (film substrate) 4: Cover glass

Claims

1. A transparent antenna used in a wireless terminal equipped with a camera unit having an image sensor having multiple pixels arranged in an array and a camera lens positioned above the image sensor, It consists of an antenna pattern included in an antenna substrate provided on the upper part of the camera lens, The aforementioned antenna pattern is composed of multiple thin metal wires. A transparent antenna in which the width of the metal wire is approximately the same as the pitch of the pixels.

2. In the transparent antenna according to claim 1, This transparent antenna is a transparent antenna with a transmittance of 80% or more.

3. In the transparent antenna according to claim 1, A transparent antenna in which the width of the aforementioned thin metal wire is 2.5 μm or less.

4. In the transparent antenna according to claim 1, The antenna pattern is a transparent antenna positioned below the position from the plurality of pixels to the shortest imaging distance of the camera unit.

5. In the transparent antenna according to claim 1, A cover glass is positioned on the upper side of the camera lens so as to cover the camera lens. The transparent antenna is a transparent antenna positioned on the underside of the cover glass.

6. In the transparent antenna according to claim 5, The antenna substrate is a transparent antenna that, when viewed in plan view, is at least as large as the cover glass.

7. In the transparent antenna according to claim 5, The antenna substrate is a transparent antenna that is larger than the camera lens when viewed in a plan view.

8. In the transparent antenna according to claim 1, The aforementioned antenna pattern is a transparent antenna formed with dimensions capable of handling frequency bands of 3.7 GHz or higher.

9. In the transparent antenna according to claim 1, The wireless terminal is a mobile phone, smartphone, tablet, or smartwatch-type electronic device, and includes a transparent antenna.

10. In the transparent antenna according to claim 1, The aforementioned antenna pattern is a transparent antenna formed on a film substrate.

11. In the transparent antenna according to claim 1, The transparent antenna is a transparent antenna having two or more of the aforementioned antenna patterns.

12. The transparent antenna according to claim 1, The aforementioned imaging sensor, A wireless terminal comprising the aforementioned camera lens.

Images