JP5063471B2 - Telescopic antenna - Google Patents

Description

  The present invention relates to an extendable antenna provided in an electronic device having at least a receiving function, particularly a mobile phone or the like that can receive terrestrial digital television broadcasts.

Although mobile phones are widespread, this mobile phone is equipped with an antenna for transmitting and receiving calls and information. In general, the antenna is built in the casing of the mobile phone or is a retractable antenna that can be expanded and contracted with respect to the casing of the mobile phone and can be stored in the casing when not in use.
Incidentally, in recent years, terrestrial digital television broadcasting has been started, and mobile phones that can receive a one-segment partial reception service of terrestrial digital television broadcasting are also known. In order to efficiently receive this one-segment partial reception service, it is necessary to make the antenna directivity match the direction of arrival of radio waves. For this reason, an antenna that can adjust the directivity characteristics of the antenna to be tiltable and rotatable with respect to the housing is suitable for the antenna that receives the one-segment partial reception service. In addition, it is preferable that the antenna can be stored in the casing of the mobile phone so that it can be easily carried during standby.

  An example of the configuration of such an extendable antenna is shown in FIG. A telescopic antenna 200 shown in FIG. 21 includes a flexible element 212, and a top portion (not shown) is provided at the tip of the element 212. In addition, a plate-like clamping piece 212 a is formed at the lower end of the element 212, and the clamping piece 212 a is pivotally supported by a clamping part 213 a formed at the tip of the antenna base part 213 by a shaft part 216. Thereby, the element 212 can be tilted with respect to the antenna base 213. The antenna base part 213 is slidably held with respect to the holder part 214, and a stopper 219 for securing is fixed to the lower end. When the holder portion 214 is attached to the casing of the mobile phone, the element 212 can be accommodated in the casing by sliding the element 212 into the holder section 214. In this state, the element 212 can be brought into an extended state by grasping the top portion and pulling out the element 212 from the holder portion 214. In the extended state, the element 212 can be tilted with respect to the antenna base 213, and can be rotated with respect to the holder portion 214 in the tilted state.

  The conventional telescopic antenna 200 shown in FIG. 21 is a retractable antenna, and the element 212 is bent so as to be able to be restored so as to absorb the impact when it receives an impact during expansion. In addition, a tilting mechanism that tilts and holds the element 212 at an arbitrary position and a rotation mechanism that rotates the tilted element 212 in a horizontal plane are provided. Although the sensitivity can be improved as the total length of the telescopic antenna 200 is increased, it is not accommodated in the space of the housing because it is housed in the housing of the mobile phone, and thus the space of the housing is not available. There was a problem that it was limited to.

  Accordingly, an object of the present invention is to provide a telescopic antenna that can be made longer than the conventional one when it is extended, even if the length is limited to the empty space of the housing at the time of storage.

  In order to achieve the above object, the telescopic antenna of the present invention comprises an antenna base that pivotally supports the lower end of the element part, and a pipe part that is slidably held inside, and the pipe part is attached to the holder. On the other hand, the main feature is that the antenna base can be expanded and contracted with respect to the pipe portion while being slidable.

  According to the present invention, the antenna base portion pivotally supporting the lower end of the element portion, and the pipe portion in which the antenna base portion is slidably held inside, the pipe portion is slidable with respect to the holder. Since the antenna base can be extended and contracted with respect to the pipe portion, the total length of the extendable antenna can be increased as much as the antenna base can be extended with respect to the pipe portion.

FIG. 1 shows the entire configuration of an extendable antenna 1 that is an embodiment of the present invention. FIG. 2 is an enlarged view of part A of the extendable antenna 1.
The telescopic antenna 1 according to the embodiments of the present invention shown in these drawings includes a first element 11 having a top portion 10 provided at the tip, and a second element that can slidably accommodate the first element 11 therein. The element part which consists of 12 is provided, and this element part is pivotally supported by the metal antenna base 13 so that tilting is possible. The top portion 10 has a disc-like shape made of a synthetic resin that serves as a knob that is gripped when the element portion including the first element 11 and the second element 12 is expanded and contracted. The first element 11 is configured by covering a flexible element conductor made of a superelastic alloy with a flexible insulating tube. Further, the second element 12 is configured by covering a coil spring, which can be bent, with a flexible insulating tube. A metal upper hold part is fitted to the upper part of the second element 12, and a metal lower hold part is fitted to the lower part. A holding spring is fixed to the lower part of the element conductor in the first element 11, and when the first element 11 is slid in the second element 12, the first element 11 is attached to the second element 12 by the action of the holding spring. The coil spring is held in elastic contact with the inner peripheral surface. As a result, the first element 11 can be pulled out from the second element 12 at an arbitrary length and held. At the lower end of the lower hold portion, which is the lower end of the second element 12, a flat plate-shaped sandwiching piece 12a having a substantially rectangular shape with rounded corners is provided.

  The antenna base portion 13 includes a sandwiching portion 13a for sandwiching the sandwiching piece 12a, and the sandwiching piece 12a is pivotally supported by the shaft portion 16 so as to be tiltable with respect to the sandwiching portion 13a (that is, the antenna base portion 13). A body portion 13b having a circular cross section with a slightly reduced outer diameter is extended from the sandwiching portion 13a, and the body portion 13b is slidable with respect to a cylindrical pipe portion 15 made of metal. Is held in. In other words, the ring portion 17 and the cylindrical spring 18 are fitted and inserted into the pipe portion 15 on the outer peripheral surface of the main body portion 13b, and the main body portion 13b is prevented from coming out of the main body portion 13b. A stopper 19 is screwed to a female screw portion provided at the lower portion of the portion 13b. The ring portion 17 and the spring 18 are interposed between the outer peripheral surface of the main body portion 13 b and the inner peripheral surface of the pipe portion 15, and the antenna base 13 is elastically formed with respect to the pipe portion 15 by the action of the spring 18. When the antenna base 13 is extended with respect to the pipe portion 15, the tip of the ring portion 17 is locked to the inside of the throttle portion 15 a that is formed on the tip of the pipe portion 15. Is done.

  The outer diameter of the pipe portion 15 is substantially equal to the outer diameter of the second element 12, and the pipe portion 15, the antenna base portion 13, and the second element 12 are slidably held in the through hole of the holder 14. . The holder 14 includes a cylindrical main body portion 14b having a flange portion 14a formed thereon. A screw portion is formed on the outer peripheral surface of the cylindrical main body portion 14b. By screwing the main body portion 14b into, for example, a hole formed in a casing of a mobile phone, the holder 14 is fixed to the mobile phone. The The telescopic antenna 1 is attached to the mobile phone. 1 and 2, the configuration of the telescopic antenna 1 in which the element portion including the first element 11 and the second element 12 is pulled out from the holder 14 and the antenna base portion 13 is pulled out from the pipe portion 15 to be in an extended state. It is shown. In the extended state, the pipe portion 15 is also pulled out from the holder 14, and the taper portion 15 b formed so that the diameter gradually increases at the lower end of the pipe portion 15 is brought into contact with the inner side of the lower end of the holder 14. Thus, the pipe portion 15 cannot be pulled out from the holder 14. The length of the telescopic antenna 1 from the lower end of the pipe portion 15 to the tip of the top portion 10 when the top portion 10 of the telescopic antenna 1 is gripped and the telescopic antenna 1 is extended is about 134 mm. The length L1 from the shaft portion 16 to the approximate center is about 21.8 mm. FIG. 3 shows a state in which the antenna base 13 is housed in the pipe portion 15. As shown in FIG. 3, when the antenna base portion 13 is stored in the pipe portion 15, a step portion formed between the sandwiching portion 13 a and the main body portion 13 b comes into contact with the tip of the pipe portion 15. . The length L2 from the lower end of the pipe portion 15 to the approximate center of the shaft portion 16 when the antenna base portion 13 is housed in the pipe portion 15 is about 15 mm, and the antenna base portion 13 can be pulled out from the pipe portion 15. The total length when the telescopic antenna 1 is pulled out can be increased by about 7 mm.

Next, an example of the configuration of the mobile phone 100 including the telescopic antenna 1 according to the embodiment of the present invention is shown in FIGS. 4 is a perspective view showing a state in which the telescopic antenna 1 is extended from the mobile phone 100 and tilted, and FIG. 5 is a perspective view showing a state in which the telescopic antenna 1 is housed in the mobile phone 100. 6 is a partially broken view showing the state where the telescopic antenna 1 has been extended from the mobile phone 100, and FIG. 7 is a partially broken view showing the state where the telescopic antenna 1 is housed in the mobile phone 100. 8 is a front view showing a tilting range when the telescopic antenna 1 is extended from the mobile phone 100, and FIG. 9 is a side view showing a rotation range when the telescopic antenna 1 is extended from the mobile phone 100. FIG. It is.
As shown in these drawings, the telescopic antenna 1 according to the present invention is attached to one side surface of a housing 100 a constituting the mobile phone 100. The casing 100a is provided with an operation unit including a numeric keypad and operation buttons (not shown) and a display 101 including a liquid crystal. The extendable antenna 1 is tiltable with respect to the housing 100a when extended, and in the state shown in FIG. The element part is configured to stand vertically. The telescopic antenna 1 can pull out the first element 11 from the second element 12 and can pull out the antenna base 13 from the pipe portion 15, so that the length of the telescopic antenna 1 can be changed in a multistage manner. Has been. Further, when the telescopic antenna 1 is retracted, the top portion 10 can be stored in the storage space provided in the housing 100a as shown in FIGS. The total length of the telescopic antenna 1 from the lower end of the pipe portion 15 to the tip of the top portion 10 when stored is about 83.9 mm. Further, the extendable telescopic antenna 1 can be tilted at an arbitrary angle with respect to the housing 100a, and the tilting range is 0 ° to about 90 ° as shown in FIG. Further, the extended telescopic antenna 1 can be rotated about the antenna base 13 as a rotation axis with respect to the casing 100a, and the rotation range can be rotated at an arbitrary angle of about 360 ° as shown in FIG. can do. As a result, the directivity characteristic of the telescopic antenna 1 attached to the mobile phone 100 can be directed in a desired direction, and the length of the telescopic antenna 1 can be changed. An antenna suitable for the mobile phone 100 that can receive a service can be obtained.

Next, the structure of each part which comprises the expansion-contraction antenna 1 of the Example of this invention is shown in FIG. 10 thru | or FIG.
FIG. 10 is a side view showing the configuration of the antenna base 13, and FIG. 11 is a plan view showing the configuration of the antenna base in a partially broken view. As shown in these drawings, the antenna base portion 13 is made of a metal such as brass, and includes a sandwiching portion 13a and a cylindrical main body portion 13b whose outer diameter is slightly narrower than the sandwiching portion 13a. A clamping groove 13c into which a clamping piece 12a formed at the lower end of the lower holding part of the second element 12 is fitted is formed in the clamping part 13a substantially at the center. An insertion hole 13e is formed in the sandwiching portion 13a for sandwiching the sandwiching piece 12a. By inserting the sandwiching piece 12a into the sandwiching groove 13c and fitting a pin serving as the shaft portion 16 into the insertion hole 13e, the second portion is formed. The element 12 is pivotably supported with respect to the antenna base 13. Further, a through hole is formed in the main body portion 13b as a whole, and a screw hole 13d in which a screw is provided is formed in a lower through hole of the main body portion 13b. A stopper 19 is screwed into the screw hole 13d. Although not shown in the figure, a pressing rod that presses the lower surface of the clamping piece 12a sandwiched by the clamping portion 13a and a coil spring that biases the pressing rod are built in the through hole of the antenna base 13. When the lower end of the coil spring is brought into contact with the upper surface of the stopper 19, the coil spring presses the pressing rod against the holding piece 12a. Thereby, when the element part which consists of the 1st element 11 and the 2nd element 12 inclines with respect to the antenna base 13, a desired inclination angle can be hold | maintained, and a click feeling is provided by providing a flat part in the lower surface of the clamping piece 12a. Can be obtained.

  Next, FIG. 12 is a side view showing the configuration of the pipe portion 15, and FIG. 13 is a side view showing the configuration of the pipe portion 15 in a sectional view. As shown in these drawings, the pipe portion 15 having a cylindrical shape is made of metal such as stainless steel, and a through hole 15c is formed throughout. A drawing portion 15a is provided by drawing so that an insertion hole 15d in which the diameter of the through hole 15c is slightly narrowed is formed at the tip portion of the pipe portion 15. The inner diameter of the diaphragm portion 15a substantially matches the outer diameter of the main body portion 13b of the antenna base portion 13. Then, the main body portion 13b of the antenna base portion 13 is inserted into the insertion hole 15d, and then the ring portion 17 and the spring 18 are fitted and inserted into the main body portion 13b located in the through hole 15c, and the stopper 19 is inserted into the screw hole 13d of the main body portion 13b. Screw on. In this case, since the maximum outer diameter of the stopper 19 substantially coincides with the inner diameter of the through hole 15c, the ring portion 17 and the spring 18 can be prevented from coming out beyond the stopper 19. Further, since the inner diameter of the insertion hole 15d substantially matches the outer diameter of the main body portion 13b, it is possible to prevent the ring portion 17 and the spring 18 from coming out beyond the throttle portion 15a. As a result, the antenna base 13 can be elastically slidable with respect to the pipe portion 15 by the spring 18 that is always interposed between the outer peripheral surface of the antenna base portion 13 and the inner peripheral surface of the pipe portion 15 and can be rotated. It is possible to move. A tapered portion 15b having a gradually increasing diameter is formed at the lower end of the pipe portion 15. The taper portion 15 b abuts on the inner side of the lower end of the holder 14 when the pipe portion 15 is pulled out from the holder 14, and prevents further pipe portion 15 from being pulled out.

  Next, FIG. 14A is a side view showing the configuration of the ring portion 17, and FIG. 14B is a side view showing the configuration of the ring portion 17 in a cross-sectional view. As shown in these drawings, the ring portion 17 is made of a metal such as brass and has a through hole 17a. The inner diameter of the through hole 17a is sized to be inserted into the main body 13b of the antenna base 13, and the outer diameter of the ring 17 can be inserted into the through hole 15c of the pipe 15 and the insertion hole of the pipe 15 The diameter is set so as not to come out of 15d, and the diameter is locked when it comes into contact with the throttle portion 15a.

  Next, FIG. 15A is a side view showing the configuration of the spring 18, and FIG. 15B is a side view showing the configuration of the spring 18 in a cross-sectional view. As shown in these drawings, the spring 18 is formed by bending a metal plate having elasticity such as phosphor bronze into a cylindrical shape, and a plurality of substantially rectangular cutout holes 18a are formed on the side surface. One part between the cutout holes 18a bulges outward to form a bulging piece 18b. The spring 18 has a shape that can be interposed between the outer peripheral surface of the antenna base portion 13 and the inner peripheral surface of the pipe portion 15, and the antenna base portion 13 is elastically formed with respect to the pipe portion 15 by the action of the bulging piece 18 b. It is made slidable and rotatable.

  Next, FIG. 16A is a side view showing the configuration of the stopper 19, and FIG. 16B is a side view showing the configuration of the stopper 19 in a cross-sectional view. As shown in these drawings, the stopper 19 is made of a metal such as brass, and has a round bar-like main body portion 19a and a disc-shaped flange portion 19c provided at one end of the main body portion 19a. It consists of and. The outer diameter of the flange portion 19c can be inserted into the pipe portion 15 and is larger than the outer diameter of the main body portion 13b of the antenna base portion 13 so that the ring portion 17 and the spring 18 cannot exceed the flange portion 19c. . A screw portion 19b is formed on the main body portion 19a, leaving a front end portion and a rear end portion. The screw portion 19b is screwed into the screw hole 13d of the antenna base portion 13, and when the screw portion 19b is screwed, the front end surface of the stopper 19 presses and contracts the coil spring housed in the main body portion 13b of the antenna base portion 13. Touched.

Here, when the telescopic antenna 1 according to the present invention is extended from the holder 14, the frequency characteristics of the VSWR of the telescopic antenna 1 when the antenna base 13 is housed in the pipe portion 15 as shown in FIG. Show. Referring to FIG. 17, a VSWR of about 1.65 is obtained when the frequency is 470 MHz, a VSWR of about 2.43 is obtained when the frequency is 570 MHz, and about 2.02 when the frequency is 670 MHz. A VSWR is obtained, and a VSWR of about 1.74 is obtained when the frequency is 770 MHz. If the VSWR is about 2.5 or less, the VSWR can be sufficiently put into practical use, and the VSWR can be further reduced by providing a matching circuit. Good VSWR characteristics are obtained.
FIG. 18 is a Smith chart showing the impedance characteristics of the telescopic antenna 1 according to the present invention. Referring to FIG. 18, when the frequency is 470 MHz, the real part is about 49.0Ω and the imaginary part is about −25.1Ω, and when the frequency is 570 MHz, the real part is about 20.8Ω and the imaginary part is about 4 When the frequency is 670 MHz, the real part is about 42.3 Ω and the imaginary part is about 32.1 Ω. When the frequency is 770 MHz, the real part is about 35.9 Ω and the imaginary part is about 18 Good impedance characteristics are obtained at .9Ω.

FIG. 19 shows the VSWR frequency characteristics of the extendable antenna 1 when the antenna base 13 is extended from the pipe portion 15 as shown in FIG. 2 when the extendable antenna 1 according to the present invention is extended from the holder 14. Referring to FIG. 19, a VSWR of about 1.68 is obtained when the frequency is 470 MHz, a VSWR of about 2.33 is obtained when the frequency is 570 MHz, and about 1.71 when the frequency is 670 MHz. VSWR is obtained, and when the frequency is 770 MHz, a VSWR of about 1.79 is obtained, and a better VSWR characteristic is obtained in the use frequency band than when the antenna base portion 13 is housed in the pipe portion 15. Yes.
FIG. 20 shows a Smith chart showing the impedance characteristics of the telescopic antenna 1 according to the present invention. Referring to FIG. 20, when the frequency is 470 MHz, the real part is about 39.3Ω and the imaginary part is about −20.7Ω, and when the frequency is 570 MHz, the real part is about 22.3Ω and the imaginary part is about 8 When the frequency is 670 MHz, the real part is about 49.9 Ω and the imaginary part is about 27.1 Ω. When the frequency is 770 MHz, the real part is about 33.1 Ω and the imaginary part is about 16 .9Ω, a better impedance characteristic is obtained in the use frequency band than when the antenna base 13 is housed in the pipe portion 15.

In the above description, it has been described as a telescopic antenna for a mobile phone or the like that can receive a one-segment partial reception service for digital terrestrial television broadcasting. However, the present invention is not limited to this, and it is necessary to tilt and rotate in a horizontal plane. It can be applied to general antennas.
Moreover, although the antenna part which consists of a 1st element and a 2nd element can be expanded-contracted in 2 steps | paragraphs, it is not restricted to this, It is good also as an antenna part of 1 step | paragraph structure which consists only of a 1st element.

It is a figure which shows the whole structure of the expansion-contraction antenna which is an Example of this invention. It is a figure which expands and shows the A section of the expansion-contraction antenna which is an Example of this invention. FIG. 3 is a cross-sectional view showing a state in which the antenna base is housed in the pipe portion in the telescopic antenna that is the embodiment of the present invention. It is a perspective view which shows the state which extended | stretched and tilted the expansion-contraction antenna concerning this invention from a mobile telephone. It is a perspective view which shows the state which accommodated the expansion-contraction antenna concerning this invention in the mobile telephone. It is a figure which shows the state which finished extending | stretching the expansion-contraction antenna concerning this invention from a mobile telephone, partially fractured | ruptured. It is a figure which shows the state which accommodated the expansion-contraction antenna concerning this invention in the mobile telephone partly broken. It is a front view which shows the tilting range at the time of extending | stretching the telescopic antenna concerning this invention from a mobile telephone. It is a side view which shows the rotation range when the expansion-contraction antenna concerning this invention is extended | stretched from a mobile telephone. It is a side view which shows the structure of the antenna base part of the expansion-contraction antenna concerning this invention. It is a top view which partially fractures | ruptures and shows the structure of the antenna base part of the expansion-contraction antenna concerning this invention. It is a side view which shows the structure of the pipe part of the expansion-contraction antenna concerning this invention. It is a side view which shows the structure of the pipe part of the expansion-contraction antenna concerning this invention with sectional drawing. It is the side view which shows the structure of the ring part of the expansion-contraction antenna concerning this invention, and its sectional drawing. It is the side view which shows the structure of the spring of the expansion-contraction antenna concerning this invention, and its sectional drawing. It is the side view which shows the structure of the stopper of the expansion-contraction antenna concerning this invention, and its sectional drawing. It is a figure which shows the frequency characteristic of VSWR at the time of accommodating the antenna base in a pipe part in the expansion-contraction antenna concerning this invention. It is a Smith chart which shows the impedance characteristic at the time of accommodating the antenna base in a pipe part in the expansion-contraction antenna concerning this invention. It is a figure which shows the frequency characteristic of VSWR at the time of extending | stretching the antenna base from a pipe part in the expansion-contraction antenna concerning this invention. It is a Smith chart which shows the impedance characteristic at the time of extending | stretching the antenna base from a pipe part in the expansion-contraction antenna concerning this invention. It is a figure which shows the structure of an example of the antenna for the conventional mobile telephones.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Telescopic antenna, 10 Top part, 11 1st element, 12 2nd element, 12a Clamping piece, 13 Antenna base part, 13a Clamping part, 13b Body part, 13c Clamping groove, 13d Screw hole, 13e Insertion hole, 14 Holder, 14a鍔 part, 14b body part, 15 pipe part, 15a throttle part, 15b taper part, 15c through hole, 15d insertion hole, 16 shaft part, 17 ring part, 17a through hole, 18 spring, 18a notch hole, 18b bulging piece , 19 Stopper, 19a Main body part, 19b Screw part, 19c collar part, 100 mobile phone, 100a case, 101 display, 200 telescopic antenna, 212 element, 212a clamping piece, 213 antenna base, 213a clamping part, 214 holder part, 216 Shaft, 219 Stopper

Claims (3)

An element portion having a flexible element, a top portion fixed to the tip of the element, and a sandwiching piece formed at the lower end;
An antenna base for tiltably holding the element part by pivotally supporting the clamping piece formed at the lower end of the element part;
The antenna base is formed of a cylindrical pipe that is held so as to be extendable and contracted , and a narrowed portion that is squeezed inward at the tip is formed with a tapered portion that is widened outwardly at the lower end. A pipe portion having an outer diameter substantially the same as the maximum diameter of the element;
A through hole in which the element portion is slidably held and a holder in which the pipe portion is held in the through hole when the element portion is pulled out;
A cylindrical spring that is interposed between an outer peripheral surface of the antenna base and an inner peripheral surface of the pipe portion, and holds the antenna base slidably and rotatably with respect to the pipe portion;
A stopper fixed to the lower end of the antenna base so that the spring does not come out of the antenna base;
When the element portion is extended from the holder and the antenna base is extended from the pipe portion, the taper portion of the pipe portion is locked to the lower end of the holder, and the throttle portion of the pipe portion A telescopic antenna, wherein the spring is prevented from coming out.   Between the outer peripheral surface of the antenna base and the inner peripheral surface of the pipe portion, a ring portion is interposed on the front side of the spring, and when the antenna portion is extended from the holder, the ring portion The telescopic antenna according to claim 1, wherein is in contact with the aperture portion.   The said pipe part is elastically held in the said through-hole by the inner peripheral surface of the said through-hole currently formed in the said holder being bulged inside. Telescopic antenna.

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