JP2002199077A - Mobile phone - Google Patents

Abstract

(57) Abstract: A mobile phone capable of more effectively reducing electromagnetic energy absorption by a human body when the mobile phone is used. An antenna, a transmitter for generating a first audio signal, a transmission circuit for modulating the first audio signal to generate and transmit a first wireless signal, and an input to the antenna 1 A receiving circuit for demodulating the second radio signal and reproducing the second audio signal, a receiver 9 for outputting a sound corresponding to the second audio signal, and a printed circuit on which the receiving circuit and the transmitting circuit are mounted The printed circuit board 5 is surrounded by the board 5, the printed circuit board 5 and the antenna 1 so as to suppress electromagnetic interference, and the transmitter 6, the receiver 9, and the shield case 4 having at least a surface having conductivity are formed. Housing 1 to store
0 and a mobile phone 101 having an electromagnetic wave reflection layer 11 formed on at least a portion between the shield case 4 and the housing 10 and containing a magnetic reflection material such as carbonyl iron.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable telephone,
In particular, the present invention relates to a mobile phone capable of reducing electromagnetic energy absorption by a human body during use.

[0002]

2. Description of the Related Art FIG. 6 is a schematic view of a conventional portable telephone. As shown in FIG. 6, the mobile phone 201 is used in a state of being close to the head H of the user. The mobile phone 201 includes an antenna 31, a feeder unit 32, a printed circuit board 33, a shield case 34, semiconductor integrated circuits 35A and 35B, a microphone 36, a keypad 37, a liquid crystal display unit 38, a speaker 39, and an insulating casing 40.

The transmitting / receiving antenna 31 protrudes from the upper end of the housing 40, transmits radio waves to the base station during transmission, and receives radio waves from the base station during reception. The antenna 31
It is a retractable antenna that can expand and contract in the longitudinal direction of the housing 40. On one surface of the printed circuit board 33, a semiconductor integrated circuit 35A including a transistor, a capacitor, a resistor and the like is provided.
Has been implemented. The semiconductor integrated circuit 35B is similarly mounted on the other surface of the printed board 33.

Printed circuit board 33 and semiconductor integrated circuit 3
The printed circuit board 35 is constituted by 5A and 35B. The printed circuit board 35 has a switching circuit, a control circuit, a transmission circuit, and a reception circuit mounted thereon. The transmission circuit and the reception circuit are connected to the antenna 31 via a switching circuit and a feeder unit 32.

[0005] The microphone 36 constitutes a transmitter, and the speaker 39 constitutes a receiver. The housing 40 has a hole 36H for the microphone 36, a hole 39H for the speaker 39, the liquid crystal display unit 3
Eight windows 38W and the like are provided. The housing 40 houses a printed circuit board 35, a shield case 34, a microphone 36, and a speaker 39.

The sound uttered by the user is supplied to the microphone 36 through the hole 36H. The microphone 36 receives a user's uttered sound or the like, and generates a first audio signal corresponding to the sound. The printed circuit board 35 converts the first audio signal into a first wireless signal. The first wireless signal is antenna 3
1 to the base station. The base station is a mobile phone 20
The second wireless signal is transmitted to the first wireless signal.

[0007] The printed circuit board 35 converts the second radio signal input to the antenna 31 into a second audio signal and supplies it to the speaker 39. The speaker 39 outputs a sound corresponding to the second audio signal and supplies the sound to the user. Printed circuit board 35, microphone 36, speaker 3
9. Power is supplied to circuits such as the liquid crystal display unit 38 from a driving power supply (battery, not shown) in the mobile phone 201.

The keypad 37 has buttons such as numeric keys, and the user uses the keypad 37 to input information such as a telephone number. The liquid crystal display section 38 displays information such as characters or images. The shield case 34 is connected to the ground layer of the printed circuit board 35, and surrounds the printed circuit board 35 so as to suppress electromagnetic interference between the printed circuit board 35 and the antenna 31. The shield case 34 is formed using a conductive material such as a metal or a plastic material having a surface coated with a metal.

In recent years, guidelines for local absorption of electromagnetic energy for mobile phones have been successively enacted in the United States, Europe and Japan. The evaluation amount of local absorption is the power absorbed per unit mass, that is, SAR (Specific Abs).
Orption Rate) is used. If the electric field penetrating the living tissue is E, the conductivity of the living tissue is σ, and the density is ρ, then SA
R is represented by the following equation (1).

SAR = σE ² / 2ρ (1)

[0011] For example, the local absorption guidelines in the United States stipulate that the peak value of the 1-gram tissue average SAR does not exceed 1.6 W / kg. According to the local absorption guidelines in Europe and Japan, the peak value of the 10-gram tissue average SAR is 2W.
/ Kg.

"Reduction of Local SAR and Ensuring Communication Characteristics by Controlling Housing Surface Current of Mobile Phone" (Journal of the Japan Society of Applied Magnetics, Vol. 23, No. 10, pp. 2005-20)
08 (1999)) describes that a local SAR is reduced by attaching a ferrite sheet to a metal housing of a mobile phone.

[0013]

The SAR tends to increase as the transmission output of the mobile phone increases and as the distance between the radio wave radiation source of the mobile phone and the human body decreases. The local SAR of the mobile phone may be highest in a portion other than the antenna, for example, near the shield case. this is,
One reason is that the size of the housing is small with respect to the wavelength of the electromagnetic wave used for wireless communication and is equal to or less than one wavelength.

For example, the wavelength of an electromagnetic wave having a frequency of 900 MHz is 330 mm, and the wavelength of an electromagnetic wave having a frequency of 2 GHz is 150 mm, whereas the length of a mobile phone in the longitudinal direction is generally about 120 mm. The power supplied to the antenna is also supplied to the conductive shield case.
Thus, the shield case, which is not an antenna in appearance, operates as a part of the antenna and serves as a radiation source of electromagnetic waves.

Another factor that causes the local SAR to be maximum near the shield case, not the antenna, is that the shield case is closer to the human head than the antenna when the mobile phone is used. At present, portable telephones distributed in the market are smaller and thinner than portable radios and the like that have been used before the spread of portable telephones. Therefore, in particular, the distance between the conductive part of the housing and the human body is reduced as compared with a portable wireless device or the like. As a result, the local SAR near the shield case increases.

FIG. 7 shows a portable telephone 20 having an electromagnetic wave absorbing layer 41 containing a magnetic loss material attached to a shield case 34.
FIG. The mobile phone 202 shown in FIG. 7 has a sheet-like electromagnetic wave absorbing layer 41 containing a magnetic loss material. Otherwise, the configuration is the same as that of the mobile phone 201 shown in FIG. 6, and the portions common to the mobile phone 201 are denoted by the same reference numerals.

In the mobile phone 202 shown in FIG. 7, examples of the magnetic loss material used for the electromagnetic wave absorbing layer 41 include ferrite, permalloy, sendust, stainless steel, silicon steel, and iron-based amorphous alloy. Also,
In the mobile phone 202, the electromagnetic wave absorbing layer 41 is attached to the human head H side of the shield case 34 via an adhesive layer. As the adhesive, for example, an ultraviolet curable or thermosetting adhesive is used.

In the portable telephone 202 having the above configuration,
To reduce the SAR, for example, by about 20%, the thickness of the electromagnetic wave absorbing layer 41 containing the magnetic loss material needs to be at least about 2 to 3 mm. Since there is a strong demand for miniaturization and weight reduction of mobile phones, thinning or weight reduction of components of the mobile phones is also desired.

The present invention has been made in view of the above problems, and it is therefore an object of the present invention to provide a portable telephone capable of more effectively reducing electromagnetic energy absorption by a human body when the portable telephone is used. I do.

[0020]

In order to achieve the above object, a portable telephone according to the present invention comprises an antenna, a transmitter for generating a first voice signal corresponding to an input sound, and the transmitter. A transmitting circuit that modulates the first audio signal from the transmitter to generate a first wireless signal, and transmits the first wireless signal via the antenna, and a second circuit that is input to the antenna.
Wireless signal, wherein the second audio signal is modulated
A receiving circuit that demodulates the wireless signal and reproduces the second audio signal, a receiver that outputs a sound corresponding to the second audio signal from the receiving circuit, and the receiving circuit and the transmitting circuit. A printed circuit board, a shield case surrounding the printed circuit board so as to suppress electromagnetic interference between the printed circuit board and the antenna, at least a surface of which is electrically conductive, the transmitter, the receiver, and the shield. It is characterized by having a housing for storing a case, and an electromagnetic wave reflection layer including a magnetic reflection material, formed at least in part between the shield case and the housing.

[0021] The portable telephone of the present invention is preferably characterized in that the electromagnetic wave reflection layer is formed near the receiver so as to be in contact with the shield case. Alternatively, the mobile phone of the present invention is preferably characterized in that the electromagnetic wave reflection layer is formed near the receiver so as to be in contact with the housing.

The mobile phone of the present invention is more preferably
The electromagnetic wave reflection layer is attached to the shield case with an adhesive. Alternatively, in the mobile phone according to the present invention, more preferably, the electromagnetic wave reflection layer is attached to the housing near the handset with an adhesive.

Preferably, the portable telephone of the present invention is characterized in that the electromagnetic wave reflecting layer has a large real part and a small imaginary part of complex permeability at the frequencies of the first and second radio signals. The mobile phone of the present invention is preferably characterized in that the electromagnetic wave reflection layer includes a layer formed by kneading and shaping the magnetic reflection material with a synthetic resin.

The portable telephone of the present invention is preferably characterized in that the magnetic reflection material contains carbonyl iron. Alternatively, the mobile phone of the present invention is preferably characterized in that the magnetic reflection material contains ferrite. The mobile phone of the present invention is preferably characterized in that the shield case has a case made of an insulating material and a conductive layer formed on the surface of the case.

This makes it possible to more effectively reduce electromagnetic energy absorption by the human body when using the portable telephone. ADVANTAGE OF THE INVENTION According to the electromagnetic wave reflection layer of the mobile telephone of this invention, the electromagnetic energy absorption by a human body can be reduced with less space compared with the case where a magnetic loss material is used.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the mobile phone according to the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 is a schematic diagram of a mobile phone according to this embodiment. As shown in FIG. 1, the mobile phone 101 is used in a state of being close to the head H of the user.

The portable telephone 101 includes an antenna 1, a feeder unit 2, a printed circuit board 3, a shield case 4, semiconductor integrated circuits 5A and 5B, a microphone 6, a keypad 7, a liquid crystal display unit 8, a speaker 9, and an insulating casing 10. Having. An electromagnetic wave reflection layer 11 including a magnetic reflection material is formed between the shield case 4 and the housing 10 so as to be close to the speaker 9. The longitudinal dimension of the housing 10 is, for example, 12 cm.

The transmitting / receiving antenna 1 protrudes from the upper end of the housing 10, transmits radio waves to the base station during transmission, and receives radio waves from the base station during reception. The antenna 1 is a retractable antenna that can expand and contract in the longitudinal direction of the housing 10. On one surface of the printed circuit board 3, a transistor,
A semiconductor integrated circuit 5A including a capacitor, a resistor, and the like is mounted. The semiconductor integrated circuit 5B is similarly mounted on the other surface of the printed circuit board 3.

Printed circuit board 3 and semiconductor integrated circuit 5
A and 5B constitute a printed circuit board 5. The printed circuit board 5 includes a switching circuit (SW) and a control circuit (CN).
T), a transmitting circuit (TRS) and a receiving circuit (RCV). Transmitting circuit and receiving circuit and antenna 1
Are connected via the switching circuit and the feeder unit 2.

The microphone 6 constitutes a transmitter, and the speaker 9
Constitutes the handset. The housing 10 has a hole 6 for the microphone 6.
H, hole 9H for speaker 9, window 8W for liquid crystal display section 8
Etc. are provided. The housing 10 houses the printed circuit board 5, the shield case 4, the microphone 6, the speaker 9, and the electromagnetic wave reflection layer 11. The microphone 6 is formed near one end of the housing 10 in the longitudinal direction. Speaker 9 is housing 10
Is formed in the vicinity of the other end in the longitudinal direction.

The sound uttered by the user is supplied to the microphone 6 through the hole 6H. The microphone 6 receives a user's utterance sound or the like and generates a first audio signal corresponding to the sound. The printed circuit board 5 converts the first audio signal into a first wireless signal. A first wireless signal is transmitted from antenna 1 to a base station. The base station transmits a second wireless signal to the mobile phone 101.

The printed circuit board 5 converts the second radio signal input to the antenna 1 into a second audio signal and supplies it to the speaker 9. The speaker 9 outputs a sound corresponding to the second audio signal and supplies the sound to the user. First
And / or the frequency of the second radio signal is eg 800
MHz or 900 MHz, or 1.8 GHz or 2 GHz. Circuits such as a printed circuit board 5, a microphone 6, a speaker 9, and a liquid crystal display unit 8 include a mobile phone 1
Power is supplied from a drive power supply (battery, not shown) in the power supply 01.

The keypad 7 has buttons such as numeric keys, and the user uses the keypad 7 to input information such as a telephone number. The liquid crystal display section 8 displays information such as characters or images. The shield case 4 is connected to the ground layer of the printed circuit board 5, and the printed circuit board 5
The printed circuit board 5 is surrounded so that electromagnetic interference between the antenna and the antenna 1 is suppressed.

The shield case 4 is made of a conductive material such as metal,
Alternatively, it is formed using a plastic material or the like having a surface coated with metal. Further, instead of applying a metal to the surface of the plastic material, metal plating such as nickel may be applied. Thereby, at least the surface of the shield case 4 becomes conductive.

An electromagnetic wave reflection layer 11 is formed on the surface of the shield case 4 in a region close to the human head during a call. The electromagnetic wave reflection layer 11 is adhered to the surface of the shield case 4 with a conductive adhesive, for example.
As the conductive adhesive, for example, an adhesive obtained by mixing aluminum or copper powder with a synthetic resin such as an epoxy resin is used. Alternatively, the electromagnetic wave reflection layer 11 can be attached using a double-sided tape or the like.

[0036] As shown in FIG.
For example, an electromagnetic wave absorbing layer 41 containing a magnetic loss material is formed on the surface of the shield case 34 for the purpose of reducing SAR. As the magnetic loss material, a material having a small real part of complex permeability and a large imaginary part as a loss term is used.
In contrast, according to the mobile phone 101 of the present embodiment,
As the magnetic reflection material for the electromagnetic wave reflection layer 11, a low-loss magnetic material having a large real part of complex magnetic permeability and a minimum imaginary part as a loss term is used.

When an AC magnetic field H is applied to the magnetic material, the magnetic flux density B
When there is a phase delay (loss angle δ) in the change of
Is represented by the following equation (2). μ = B / H = | μ | e− ^j (2) The complex magnetic permeability μ expressing this complexly is expressed by the following equation (3). μ = μ′−jμ ″ = | μ | cos δ−j | μ | sin δ (3)

Δ = 0 corresponds to the DC magnetic permeability. Since cos δ decreases as δ increases, the real part μ ′ of complex permeability
Decreases. On the other hand, μ ″ = | μ | sin δ corresponds to the energy loss. Since δ increases as the frequency increases, the imaginary part μ ″ also increases. The real part μ ′ and the imaginary part μ ″ of the complex magnetic permeability of the magnetic material change at a specific frequency due to the influence of magnetic resonance or the like.

FIG. 2A is a diagram schematically showing the complex magnetic permeability μ ′ and μ ″ of the electromagnetic wave reflection layer 11 of the mobile phone of the present embodiment. As shown in FIG. 2A, the electromagnetic wave reflection layer 11 of the mobile phone according to the present embodiment has a high frequency band (for example, 1 to 2 GHz) used for the first and second wireless signals.
And the resonance frequency are separated, the real part μ ′ of the complex magnetic permeability is large, and the imaginary part μ ″ is small.

On the other hand, FIG. 2B shows the complex magnetic permeability μ ′ of the electromagnetic wave absorbing layer 41 of the conventional portable telephone 202 shown in FIG.
FIG. 4 is a diagram schematically illustrating μ ″. As shown in FIG. 2B, the electromagnetic wave absorbing layer 41 of the conventional mobile phone is provided with a high frequency band (for example, 1 band) used for the first and second wireless signals.
Since the resonance frequency is close to the resonance frequency, the real part μ ′ of the complex permeability becomes smaller and the imaginary part μ ″ becomes larger when the specific frequency is exceeded.

The electromagnetic wave reflection layer 1 of the mobile phone according to the present embodiment
1, low-loss magnetic materials such as carbonyl iron,
Powder such as low-loss ferrite or flat powder is used. The powder of such a low-loss magnetic material is kneaded with a resin such as chlorinated polyethylene or silicon and molded into a predetermined shape. For example, carbonyl iron having a particle size of about 5 to 20 μm is
By kneading with chlorinated polyethylene so that the content of carbonyl iron becomes 80 wt%, and forming into a sheet,
The electromagnetic wave reflection layer 11 is formed.

As shown in FIG. 7, an electromagnetic wave absorbing layer 41 made of a magnetic loss material is formed, and the local SAR is reduced to, for example, 20%.
In order to reduce the size, 3-5cm square size and 2-3m thickness
The electromagnetic wave absorbing layer 41 needs to be about m. On the other hand, to form the electromagnetic wave reflection layer 11 and reduce the local SAR to the same extent, the electromagnetic wave reflection layer 11 having a size of 3 to 5 cm square and a thickness of about 0.5 mm may be formed. Therefore, S
A member for reducing AR can be made thinner and lighter.

In the mobile phone 101, the length of the housing 10 in the longitudinal direction is small with respect to the wavelength of the radio signal, and the conductive portion such as the shield case 4 operates as a part of the antenna. Therefore, when an electromagnetic wave is received or transmitted from the antenna 1, a current flows on the surface of the conductive portion such as the shield case 4, which causes an increase in local SAR.

However, the mobile phone 1 of the present embodiment
According to No. 01, the electromagnetic wave reflection layer 11 is formed in close contact with the surface of the shield case 4 near the speaker 9, that is, at the position where the surface current is maximum. Therefore, the electromagnetic wave radiated to the human body outside the housing 10 is reflected by the electromagnetic wave reflecting layer 1.
1 is reflected. Thereby, SAR is reduced.

FIG. 3 is a block diagram schematically showing the operation of mobile phone 101 in FIG. As shown in FIG. 3, the switching circuit (SW) 2A, the control circuit (CNT) 21, the transmitting circuit (TRS) 22, and the receiving circuit (RCV) 23 are composed of the semiconductor integrated circuits 5A and 5B and the printed circuit board 3 of FIG. 1 and mounted on the printed circuit board 5 of FIG.

A microphone (MIC) 6 receives a user's uttered sound or the like, and converts the input sound into an electroacoustic signal to generate a first audio signal S1 corresponding to the input sound. The transmission circuit (TRS) 22 modulates the first audio signal S1 to convert it into a first unvoiced signal S11, and this first radio signal S1
1 is output to the switching circuit (SW) 2A. Switching circuit (S
W) 2A supplies the first radio signal S11 from the transmission circuit (TRS) 22 to the antenna 1 via the feeder unit 2. The antenna 1 converts the first wireless signal S11 from an electric signal to a radio wave and sends the radio wave to a base station.

The second radio signal S12 obtained by modulating the second audio signal S2 is input to the antenna 1. The antenna 1 supplies the second wireless signal S12 to the switching circuit (SW) 2A via the feeder unit 2. The switching circuit 2A
The second radio signal S12 from the antenna 1 is supplied to a receiving circuit (RCV).

The receiving circuit (RCV) 23 demodulates the second radio signal S12 to generate a second audio signal S2, and outputs the second audio signal S2 to the speaker 9. The speaker 9 outputs a sound corresponding to the second audio signal S2 by performing electro-acoustic conversion on the second audio signal S2, and supplies the output sound to the user's ear.

The control circuit (CNT) 21
01, that is, the transmission circuit (TRS) 22,
The receiving circuit (RCV) 23, the switching circuit (SW) 2A, and the liquid crystal display (LCD) 8 are controlled. Further, the control circuit (CNT) 21 controls a transmission / reception sequence, a transmission / reception protocol, and the like.

Information is input to the control circuit (CNT) 21 from the keypad (PAD) 7. Control circuit (CN
T) 21 performs various signal processing based on input information of the keypad (PAD) 7. The control circuit (CNT) 21 controls the display of the liquid crystal display (LCD) 8, and displays, for example, information input to the keypad (PAD) 7 on a display screen.

According to the portable telephone of the present embodiment,
It is possible to reduce electromagnetic energy absorbed in a human head when using a mobile phone. Further, according to the mobile phone of the present embodiment, by using the magnetic reflection material, the SAR can be reduced in a smaller space as compared with the case where the magnetic loss material is used.

Further, according to the portable telephone of this embodiment, the electromagnetic energy radiated from the inside of the portable telephone toward the head of the human body is reflected by the electromagnetic wave reflection layer 11, and a part thereof is transmitted from the antenna 1. Radiated. Therefore, antenna radiation efficiency and communication characteristics are improved.

(Embodiment 2) FIG. 4 is a schematic diagram of a mobile phone according to this embodiment. As shown in FIG. 4, the mobile phone 102 of the present embodiment is such that the electromagnetic wave reflection layer 11 of the mobile phone 101 of the first embodiment shown in FIG. 1 is provided not on the surface of the shield case 4 but on the housing 10 side. . Although not shown in FIG. 4, the mobile phone 102 of FIG. 4 has the speaker 9 and the hole 9 for the speaker in the same manner as the mobile phone 101 of FIG.
H (see FIG. 1) is formed.

FIG. 5 is a sectional view taken along the line AA 'of FIG. As shown in FIG. 5, according to the mobile phone 102,
The speaker 9 and the electromagnetic wave reflection layer 11 are formed adjacent to each other. That is, according to the mobile phone 102, the speaker and the electromagnetic wave reflection layer 11 are formed side by side in a direction perpendicular to the plane of FIG.

Other configurations, ie, antenna 1, feeder unit 2, printed circuit board 3, shield case 4, semiconductor integrated circuits 5A and 5B, microphone 6, keypad 7, liquid crystal display unit 8, speaker 9, and insulating casing Reference numeral 10 is common to the mobile phone 101 (see FIG. 1).

Printed circuit board 3 and semiconductor integrated circuit 5
A and 5B constitute a printed circuit board 5. The operations of the switching circuit, the control circuit, the transmission circuit, and the reception circuit mounted on the printed circuit board 5 are the same as those of the mobile phone according to the first embodiment, and thus the description thereof is omitted.

According to the above-described portable telephone according to the embodiment of the present invention, similarly to the portable telephone according to the first embodiment, it is possible to reduce the electromagnetic energy absorbed in the human head when using the portable telephone. In addition, by using a magnetic reflection material, SAR can be reduced in a small space as compared with a case where a magnetic loss material is used. Further, the electromagnetic energy radiated from the inside of the mobile phone toward the head of the human body is reflected on the electromagnetic wave reflection layer 11 and a part thereof is radiated from the antenna 1, so that the antenna radiation efficiency and the communication characteristics are improved.

The embodiment of the portable telephone of the present invention is not limited to the above description. For example, the mixing ratio between the magnetic reflection material and the synthetic resin can be appropriately changed according to the frequency band. In addition, various changes can be made without departing from the gist of the present invention.

[0059]

According to the portable telephone of the present invention, it is possible to more effectively reduce electromagnetic energy absorption by a human body when the portable telephone is used.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a mobile phone according to a first embodiment of the present invention.

FIG. 2A is a diagram illustrating a complex magnetic permeability of an electromagnetic wave reflection layer of the mobile phone according to the first embodiment of the present invention.
(B) is a diagram showing the complex magnetic permeability of an electromagnetic wave absorbing layer of a conventional mobile phone.

FIG. 3 is a schematic block diagram of the mobile phone according to the first embodiment of the present invention.

FIG. 4 is a schematic diagram of a mobile phone according to a second embodiment of the present invention.

FIG. 5 is a cross-sectional view taken along line A-A 'of FIG.

FIG. 6 is a schematic diagram of a conventional mobile phone.

FIG. 7 is a schematic view of a conventional mobile phone.

[Explanation of symbols]

1, 31 ... antenna, 2, 32 ... feeder section, 2A ... switching circuit (SW), 3, 33 ... printed circuit board, 4, 34 ...
Shield case, 5, 35 ... printed circuit board, 5A, 5
B, 35A, 35B: semiconductor integrated circuit, 6, 36: microphone, 6H, 9H, 36H, 39H: hole, 7, 37: keypad, 8, 38: liquid crystal display section, 9, 39: speaker, 10, 40 ... Case, 11 ... Electromagnetic wave reflection layer, 21 ... Control circuit (CNT), 22 ... Transmission circuit (TRS), 23 ...
Receiving circuit (RCV), 41 ... electromagnetic wave absorbing layer, 101, 1
02, 201, 202 ... mobile phone.

Continuation of the front page F term (reference) 5J046 AA03 AA17 AB06 DA03 UA08 5J047 AA03 AA17 AB06 FD01 5K023 AA07 BB23 BB28 DD06 LL01 LL05

Claims (10)

[Claims] An antenna, a transmitter for generating a first audio signal corresponding to an input sound, and a first radio signal modulated by modulating the first audio signal from the transmitter. A transmission circuit that generates and transmits the first wireless signal via the antenna; and a second wireless signal that is a second wireless signal input to the antenna, wherein a second audio signal is modulated. And demodulate
A receiving circuit for reproducing the second audio signal; a receiver for outputting a sound corresponding to the second audio signal from the receiving circuit; a printed circuit board on which the receiving circuit and the transmitting circuit are mounted; A shield case surrounding the printed circuit board so as to suppress electromagnetic interference between the printed circuit board and the antenna, and a shield case having at least a conductive surface; and a housing for storing the transmitter, the receiver, and the shield case, A mobile phone having an electromagnetic wave reflection layer containing a magnetic reflection material, formed at least in part between the shield case and the housing. 2. The portable telephone according to claim 1, wherein said electromagnetic wave reflection layer is formed near said receiver so as to be in contact with said shield case. 3. The portable telephone according to claim 1, wherein said electromagnetic wave reflection layer is formed near said receiver so as to be in contact with said housing. 4. The mobile phone according to claim 2, wherein said electromagnetic wave reflection layer is attached to said shield case with an adhesive. 5. The portable telephone according to claim 3, wherein said electromagnetic wave reflection layer is attached to said housing near said receiver by an adhesive. 6. The electromagnetic wave reflection layer has a large real part of complex permeability at the frequencies of the first and second radio signals,
The mobile phone according to claim 1, wherein an imaginary part is small. 7. The portable telephone according to claim 6, wherein said electromagnetic wave reflection layer includes a layer obtained by kneading and molding said magnetic reflection material with a synthetic resin. 8. The portable telephone according to claim 7, wherein said magnetic reflection material contains carbonyl iron. 9. The portable telephone according to claim 7, wherein said magnetic reflection material includes ferrite. 10. The portable telephone according to claim 1, wherein said shield case has a case made of an insulating material and a conductive layer formed on a surface of said case.