JP2007043558A - Mobile communication terminal device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mobile communication terminal which is capable of facilitating adjustment for reduction of SAR and acquisition of satisfactory communication characteristics when being changed in size and material of an enclosure. <P>SOLUTION: In the mobile communication terminal wherein an antenna element 22 radiating an electromagnetic wave for communication is built in a prescribed enclosure 21, a support member 23 made of a non-conductive material is disposed between an inside wall of the enclosure 21 and the antenna element 22 and is configured so that the antenna element 22 is supported with at least a part of the support member 23 in contact with the antenna element 22. The material of the support member 23 is different from that of the enclosure 21 and its thickness is uniform at a part in contact with the antenna element 22. When the reference terminal model exists, material and thickness of the support member 23 are the same as those of the reference terminal model. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a mobile communication terminal device in which an antenna element that radiates electromagnetic waves for communication is incorporated in a predetermined housing, for example, like a mobile phone terminal.

  In recent years, it has been pointed out that an electromagnetic wave emitted from a mobile communication terminal device such as a mobile phone terminal has an effect on a human body, and it is required for a mobile phone terminal or the like to reduce the influence. Specifically, SAR (Specific Absorption Rate) is used as an index representing the degree of influence. The SAR is the amount of energy absorbed in a unit mass of tissue per unit time, and it is possible to know how much energy the human body receives from a device that emits a certain radio wave in a certain time.

  In Japan, two standard values are defined: “whole body average SAR” and “local SAR”. The unit used is W / kg and represents how many watts (W) of thermal energy is absorbed per kilogram (kg). In other words, the larger the value, the greater the influence on the human body. Local SAR is used for electromagnetic waves transmitted from wireless devices used near the human head, such as mobile phones.

  It is known that the actual SAR changes due to various factors as well as the transmission output of a mobile phone terminal or the like. That is, the SAR changes depending on the structure of the antenna element and the antenna holding portion, how to perform antenna grounding, and the like. Accordingly, manufacturers that manufacture mobile phone terminals and the like are devised to reduce the SAR and obtain the best communication characteristics. In practice, grounding, shielding, and electrical approaches are common.

As a conventional technique of a mobile phone terminal considering SAR, for example, a technique disclosed in Patent Document 1 is known.
JP 2005-176291 A

  By the way, there are many models of devices such as mobile phone terminals, and model changes including addition of functions tend to be frequently performed. Therefore, it is difficult to perform adjustment for optimizing the SAR characteristic for each model or for each model change.

  In addition, for example, in order to make it possible to continuously use a mobile phone terminal for a long time, it is necessary to increase the size of the battery, but in order to mount a large battery, the casing of the terminal must be increased in size. I don't get it. When making a new model in accordance with such a need, it is possible to adopt a common antenna element and a common electric circuit board with another existing model, but the size of the case etc. Must be changed. However, if the material and size of the housing used in the new model is different from that of another existing model, the SAR characteristics change, so the SAR must be optimized again.

  Specifically, when the casing is enlarged and the thickness of the casing is increased, the space inside the casing is widened, and the antenna element is supported in a state of floating from the casing. As a result, SAR deteriorates. In this case, as a specific example of the countermeasure, it is conceivable to provide a conductor such as a copper foil inside the casing to partially shield the electromagnetic wave. However, it is necessary to process the housing and devise grounding, which requires very troublesome work.

  It is an object of the present invention to provide a portable communication terminal device capable of reducing the SAR and facilitating adjustment for obtaining good communication characteristics when the size or material of the casing is changed. Objective.

  The present invention is a mobile communication terminal device in which an antenna element that radiates electromagnetic waves for communication is incorporated in a predetermined housing, and is non-conductive between an inner wall of the housing and the antenna element. A support member made of the above material is disposed, and the antenna element is supported in a state where at least a part of the support member is in contact with the antenna element.

  A support member made of a non-conductive material is disposed between the inner wall of the housing and the antenna element. As a result, the influence of the support member is dominant on the SAR of the mobile communication terminal device, and the influence of the housing itself is considered to be almost eliminated. Therefore, the SAR characteristic is adjusted in advance. By using the antenna element and the support member, it is not necessary to readjust the SAR characteristics even if the material, shape, or size of the housing is changed.

  As an experiment, the inventor created a plurality of test cases having the same structure and different materials only, and supported the same antenna element on each test case via the support member. The SAR was measured for the housing. As a result, the influence of the difference in the test case did not appear in the measured SAR. From this result, the following matters can be estimated. That is, the influence on the SAR characteristic depends on the member that is in contact with and supported by the antenna element, and the material of the casing (assuming a dielectric) that is separated from the antenna element has little influence.

  In addition, a material that is different from the housing can be used as the support member.

  Even when the support member is commonly used for a plurality of models, various materials can be used for the casing as necessary. When the support member is used, it is considered that the material of the housing does not affect the SAR.

  Further, only the support member may be disposed between the inner wall of the casing and the antenna element.

  By adopting such a configuration, a mobile communication terminal device having a simple configuration can be realized without providing a shielding material around the antenna element.

  In addition, regarding the support member, at least the thickness of the portion in contact with the antenna element can be made uniform.

  It is considered that the SAR characteristic of the mobile communication terminal device largely depends on the structure and material of the support member that supports the antenna element. In the third aspect of the invention, since the thickness of the portion of the support member that contacts the antenna element is uniform, it is easy to adjust the characteristics of the support member itself.

  Further, when there is a reference terminal model that adopts the antenna element and optimizes the SAR characteristics, the material of the support member is the same material as the case of the reference terminal model, and the thickness of the support member is Can be set to approximately the same dimension as the thickness of the casing of the reference terminal model.

  When the same antenna element as that of the existing reference terminal model that has already optimized the SAR characteristics and communication characteristics is adopted, the portion in contact with the antenna element, that is, the material and thickness of the support member are equivalent to those of the reference terminal model. If it is determined that the conditions are satisfied, it is considered that the SAR characteristic equivalent to that of the reference terminal model can be obtained, so that the optimum characteristic can be realized without readjustment.

  According to the present invention, the influence of the support member is dominant on the SAR of the mobile communication terminal device, and it is considered that the influence of the housing itself is almost eliminated. Therefore, the SAR characteristics are optimized in advance. By using the antenna element adjusted in this way and the support member, it is not necessary to readjust the SAR characteristics even if the material, shape, and size of the housing are changed.

  One embodiment of the portable communication terminal device of the present invention will be described below with reference to FIGS.

  FIG. 1 is an exploded perspective view of a main part of the cellular phone terminal according to the embodiment and a portion A shown in FIG. FIG. 2 is a plan view of the antenna characteristic adjusting member shown in FIG. FIG. 3 is an exploded perspective view showing the configuration of the main part of the mobile phone terminal of the reference terminal model. FIG. 4 is a perspective view showing the appearance of the entire mobile phone terminal. FIG. 5 is a perspective view showing a part of the mobile phone terminal shown in FIG.

  In this embodiment, as a specific example, the present invention is applied to a mobile phone terminal 10 as shown in FIG. A cellular phone terminal 10 shown in FIG. 4 includes a lower body 11, an upper body 12, and a hinge portion 13. The upper body 12 rotates relative to the lower body 11 with the hinge portion 13 as an axis. By doing so, it can be opened or folded into the state shown in FIG. Similar to a general mobile phone terminal, an operation unit 51 provided with a number of buttons such as a numeric keypad is provided on the upper surface of the lower body 11, and a character string or an image is necessary on the upper surface of the upper body 12. A display unit 52 for displaying various information is provided.

  Main components such as an electric circuit board and an antenna for realizing the function of the mobile phone terminal 10 are accommodated in an internal space of the casing 21 constituting the lower body 11. Details of the lower body 11 are shown in FIG. FIG. 5 shows a state in which a part of the casing 21 is cut away. As shown in FIG. 5, the housing 21 is configured in a hollow structure like a box by combining two members of a lower member 21 a and an upper member 21 b in a vertical combination. The antenna element 22 and an electric circuit board (not shown) are incorporated in the internal space of the housing 21. The antenna element 22 is used when transmitting and receiving radio waves with a predetermined base station in order to realize a communication function of a mobile phone.

  Details of the portion A shown in FIG. 5, that is, the support structure for the antenna element 22 is shown in FIG. 1. In the example shown in FIG. 1, it is assumed that the thickness H1 of the lower member 21a of the casing 21 is relatively large. In reality, in order to respond to various requests from users, even if the antenna element 22 and the electric circuit board to be used are the same, a plurality of types of cases having different sizes, shapes, and materials are used separately to make mobile phone terminals. There are cases where 10 multiple models are manufactured. For example, in order to enable continuous use for a long time, it is necessary to mount a large battery, and for this purpose, the thickness H1 of the housing 21 must be larger than usual.

  When it is not necessary to mount a large battery, the thickness H2 of the lower member 21Ba of the casing 21 can be made smaller than H1 as shown in FIG. The structure shown in FIG. 3 shows a case of a mobile phone terminal of a reference terminal model. That is, various models of mobile phone terminals can be created by using a reference terminal model as shown in FIG. 3 as a standard and partially changing the components and structure.

  As described above, in a device such as a mobile phone terminal, it is necessary to optimize characteristics so as to reduce SAR, which is an index of the degree of influence of generated electromagnetic waves on the human body, and to obtain desirable communication characteristics. . Therefore, when a reference terminal model exists, it is necessary to make an adjustment to optimize the SAR characteristic for the reference terminal model first. Further, when another model is created by changing the reference terminal model, it is desirable that readjustment for optimizing the SAR characteristic is not necessary.

  In the reference terminal model shown in FIG. 3, since the thickness H2 is small, the antenna element 22 is directly covered on the inner wall portion of the lower member 21Ba of the casing 21, and the antenna element 22 is supported by the lower member 21Ba. It has become. The material of the lower member 21Ba is a non-conductive material and is also a dielectric.

  On the other hand, when the same antenna element 22 is employed for the lower member 21a having a large thickness H1, as shown in FIG. 1, a larger space is created inside the lower member 21a, so that the antenna element 22 is in a floating state. Thus, it is supported by the lower member 21a. In that case, the SAR characteristic of the mobile phone terminal 10 may change significantly with respect to the above-described reference terminal model, and readjustment is necessary.

  Therefore, in this embodiment, as shown in FIG. 1, an antenna characteristic adjusting member 23 is interposed between the antenna element 22 and the lower member 21a. That is, the lower member 21 a supports the antenna characteristic adjustment member 23, and the antenna characteristic adjustment member 23 supports the antenna element 22. In particular, in the present embodiment, only the antenna characteristic adjustment member 23 is disposed between the inner wall of the casing 21 and the antenna element 22, and a portable communication terminal device having a simple configuration is provided without providing a shield material around the antenna element. Realized.

  The material of the antenna characteristic adjusting member 23 is a non-conductive material and is a dielectric. In addition, when a reference terminal model as shown in FIG. 3 exists, the same material as that of the lower member 21Ba of the casing 21 is used as the material of the antenna characteristic adjusting member 23. The material of the lower member 21a shown in FIG. 1 may be the same as or different from the lower member 21Ba of the reference terminal model.

  Further, the antenna characteristic adjusting member 23 shown in FIG. 1 is made of a material formed in a thin plate shape, and has a planar shape slightly larger than the antenna element 22 as shown in FIG. That is, the antenna characteristic adjusting member 23 is supported and supported from the lower side over almost the entire antenna element 22. Further, the surfaces 23a, 23b, 23c, and 23d of the antenna characteristic adjusting member 23 that are in contact with the antenna element 22 are formed so that their thickness t is uniform. Further, when a reference terminal model as shown in FIG. 3 exists, the thickness t of each surface 23a, 23b, 23c, 23d is determined by the portion of the reference terminal model where the lower member 21Ba supports the antenna element 22. It is desirable to set it equal to the wall thickness.

  As shown in FIG. 1, when the thickness H1 of the lower member 21a is relatively large, the internal space of the housing 21 becomes large, so that the antenna element 22 is mounted in a state of floating from the lower member 21a. There is a possibility, however, when such a significant change occurs in the support structure with respect to the reference terminal model, the SAR characteristics may also change greatly. However, when the antenna characteristic adjusting member 23 is disposed between the lower member 21a of the housing 21 and the antenna element 22 as shown in FIG. 1, it is possible to prevent an increase in the gap between the portions that support the antenna element 22. In addition, the contact state (contact area, contact portion material thickness, contact portion material) between the antenna element 22 and the antenna characteristic adjusting member 23 is determined between the antenna element 22 and the lower member 21Ba in the reference terminal model. Since it becomes equivalent to the contact state, a change in the SAR characteristic can be avoided. As a result, readjustment of the SAR characteristic becomes unnecessary.

  In order to confirm the usefulness of the structure shown in FIG. 1, the present inventor prepared a plurality of test casings having the same structure and different materials only as the casing 21. As shown in FIG. 1, the same antenna element 22 was supported via the antenna characteristic adjusting member 23, and the SAR was measured for each test casing. As a result, the influence of the difference in the test case did not appear in the measured SAR.

  From this result, the following matters can be estimated. That is, the influence on the SAR characteristic depends on the member that is in contact with and supported by the antenna element, and the material of the casing (assuming a dielectric) that is separated from the antenna element has little influence. That is, when the antenna element 22 is supported using the antenna characteristic adjusting member 23 as shown in FIG. 1, the characteristics of the antenna characteristic adjusting member 23 itself, the contact state between the antenna characteristic adjusting member 23 and the antenna element 22, etc. Since the influence becomes dominant, it is not necessary to readjust the SAR characteristics even when the material, shape, and size of the other casing 21 are changed.

On the other hand, in a mobile phone terminal having a conventional configuration that does not use the antenna characteristic adjustment member 23, the SAR characteristic changes depending on the difference in the material or size of the casing, the difference in the shape of the antenna support portion, and the like as described below. . Here, sample 1, sample 2, sample 3 and sample 4 of four types of mobile phone terminals having different materials or sizes of the casing or the structure of the support portion of the antenna are prepared, and SAR [mW / g] (GSM, 1 g ave) and effective radiated power ERP (Effected Radiated Power: GSM open) were measured.
Sample 1 (MX6 w / o SAR chassis, housing material glass 30%)
SAR: 1.47
ERP: -0.69
Sample 2 (MX6 w SAR chassis, case material glass 30%)
SAR: 1.21
ERP: -1.32
Sample 3 (VS3, housing material glass 30%)
SAR: 1.22
ERP: -1.55
Sample 4 (MX6 w SAR chassis, case material glass 20%)
SAR: 1.17
ERP: -1.27

  From this result, when the antenna characteristic adjusting member 23 is not used, it is necessary to readjust to optimize the SAR characteristic and the communication characteristic every time the material of the casing and the support structure of the antenna are changed. .

  Although various embodiments of the present invention have been described above, the present invention is not limited to the matters shown in the above-described embodiments, and those skilled in the art can make modifications and applications based on the description and well-known techniques. This is also the scope of the present invention, and is included in the scope for which protection is sought.

  In the portable communication terminal device according to the present invention, when the same antenna element is employed, the SAR characteristics do not change even when the material and size of the housing and the support structure of the antenna are changed. If the SAR characteristics are optimized in advance for the reference terminal model, it is not necessary to readjust the SAR characteristics every time the model is changed or the model is changed, and the increase in manufacturing cost can be significantly suppressed. The present invention can be used not only for mobile phone terminals but also for various terminals having a wireless communication function such as a portable information communication terminal (PDA).

FIG. 6 is an exploded perspective view of a portion A shown in FIG. 5 which is a main part of the mobile phone terminal according to the embodiment. It is a top view of the antenna characteristic adjustment member shown in FIG. It is a disassembled perspective view which shows the structure of the principal part in the mobile telephone terminal of a reference | standard terminal model. It is a perspective view which shows the external appearance of the whole mobile telephone terminal. It is a perspective view which shows a part of mobile telephone terminal shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Mobile phone terminal 11 Lower body 12 Upper body 13 Hinge part 21 Case 21a Lower member 21b Upper member 22 Antenna element 23 Antenna characteristic adjustment member 51 Operation part 52 Display part

Claims (5)

A mobile communication terminal device in which an antenna element that radiates electromagnetic waves for communication is incorporated in a predetermined housing,
A support member made of a non-conductive material is disposed between the inner wall of the housing and the antenna element, and the antenna element is supported in a state where at least a part of the support member is in contact with the antenna element. Mobile communication terminal device. The mobile communication terminal device according to claim 1,
A mobile communication terminal device using a material that is different from the housing as the support member. The mobile communication terminal device according to claim 1,
The portable terminal device which has arrange | positioned only the said supporting member between the inner wall of the said housing | casing, and the said antenna element. The mobile communication terminal device according to claim 1,
A portable communication terminal device in which a thickness of at least a portion in contact with the antenna element is uniform with respect to the support member. The mobile communication terminal device according to claim 4,
When there is a reference terminal model that employs the antenna element and optimizes the SAR characteristics,
A portable communication terminal device that uses the same material as the housing of the reference terminal model as the material of the support member, and the thickness of the support member is determined to be approximately the same as the thickness of the housing of the reference terminal model .

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