Abstract: A method for producing polytetrafluoroethylene, which includes polymerizing tetrafluoroethylene in an aqueous medium in the presence of a nucleating agent and a hydrocarbon anionic surfactant to obtain polytetrafluoroethylene. A total amount of the nucleating agent and the hydrocarbon anionic surfactant at the initiation of polymerization is more than 50 ppm based on the aqueous medium.

Abstract: One object is to prevent electromagnetic wave interference between electronic components with restricted increase of the size of a circuit module. A circuit module according to an embodiment includes a circuit board, a plurality of electronic components provided on the circuit board, a resin mold provided on the circuit board so as to seal the plurality of electronic components in an insulating manner, a conductive shield covering the top surface and the side surfaces of the resin mold, and a plurality of conductive poles having a columnar shape provided in the resin mold and connecting the top surface of the conductive shield and the ground of the circuit board. The resonance caused by frequencies equal to or less than a predetermined maximum usable frequency is restricted.

Abstract: One object is to prevent electromagnetic wave interference between electronic components with restricted increase of the size of a circuit module. A circuit module according to an embodiment includes a circuit board, a plurality of electronic components provided on the circuit board, a resin mold provided on the circuit board so as to seal the plurality of electronic components in an insulating manner, a conductive shield covering the top surface and the side surfaces of the resin mold, and a plurality of conductive poles having a columnar shape provided in the resin mold and connecting the top surface of the conductive shield and the ground of the circuit board. The resonance caused by frequencies equal to or less than a predetermined maximum usable frequency is restricted.

Abstract: A communication module includes a circuit substrate having a first high-frequency processing section related to mobile phone communication, a second high-frequency processing section that processes reception signals related to satellite positioning systems, a system section having a baseband processing section and application processing section, and a power circuit section, a sealing member covering the electronic components mounted on the circuit substrate, a conductive shield layer formed on a surface of the sealing member, and a shield wall formed in the sealing member so as to demarcate a mounting area of the first high-frequency processing section and a mounting area of the second high-frequency processing section.

Abstract: A communication module includes a circuit substrate having a first high-frequency processing section related to mobile phone communication, a second high-frequency processing section that processes reception signals related to satellite positioning systems, a system section having a baseband processing section and application processing section, and a power circuit section, a sealing member covering the electronic components mounted on the circuit substrate, a conductive shield layer formed on a surface of the sealing member, and a shield wall formed in the sealing member so as to demarcate a mounting area of the first high-frequency processing section and a mounting area of the second high-frequency processing section.

Abstract: A communication module includes a circuit substrate having a first high-frequency processing section related to mobile phone communication, a system section having a baseband processing section and application processing section, and a power circuit section, a sealing member covering the electronic components mounted on the circuit substrate, a conductive shield layer formed on a surface of the sealing member, and a shield wall formed in the sealing member so as to demarcate one or both mounting areas of the system section and power circuit section and the mounting area of the first high-frequency processing section. The circuit substrate includes a core layer that is a conductive layer thicker than the other conductive layers and that functions as a ground. Electronic components are arranged in through-holes formed in the core layer.

Abstract: To prevent the local heating of an electronic apparatus chassis, there is provided a push button switch (10), which comprises a substrate (11) having a first contacting part (11a) and a second contacting part (11b) operable to be brought into electrical conduction with the first contacting part (11a), and a flexible electrically insulating sheet (13) covering the substrate (11) and having a click portion (13a) on the inside of which the first and second contacting parts are disposed to be brought into and out of electrical conduction therebetween in response to depression of the click portion. The electrically insulating sheet (13) includes a heat conducting layer (14) extending along the substrate (11).

Abstract: It is an object of the present invention to provide a key sheet and the like which can suppress local elevation of temperature, and effectively diffuse heat loss from electronic circuits. The key sheet includes: a viscoelastic sheet 16b having a viscoelastic property, and having a first surface and a second surface; a button section 16a located on the side of the first surface of the viscoelastic sheet 16b; a thermally-conductive sheet 14 located along the first surface or the second surface of the viscoelastic sheet 16b, the thermally-conductive sheet 14 having a thermal conductivity equal to a specific value; and a contact section 16d projected from the second surface of the viscoelastic sheet 16b, the contact section occupies a position corresponding to the button section 16a.

Abstract: It is an object of the present invention to provide a key sheet and the like which can suppress local elevation of temperature, and effectively diffuse heat loss from electronic circuits. The key sheet includes: a viscoelastic sheet 16b having a viscoelastic property, and having a first surface and a second surface; a button section 16a located on the side of the first surface of the viscoelastic sheet 16b; a thermally-conductive sheet 14 located along the first surface or the second surface of the viscoelastic sheet 16b, the thermally-conductive sheet 14 having a thermal conductivity equal to a specific value; and a contact section 16d projected from the second surface of the viscoelastic sheet 16b, the contact section occupies a position corresponding to the button section 16a.

Abstract: To prevent the local heating of an electronic apparatus chassis, there is provided a push button switch (10), which comprises a substrate (11) having a first contacting part (11a) and a second contacting part (11b) operable to be brought into electrical conduction with the first contacting part (11a), and a flexible electrically insulating sheet (13) covering the substrate (11) and having a click portion (13a) on the inside of which the first and second contacting parts are disposed to be brought into and out of electrical conduction therebetween in response to depression of the click portion. The electrically insulating sheet (13) includes a heat conducting layer (14) extending along the substrate (11).

Abstract: A high frequency power amplifier including: a multi-layer printed-circuit board, a transistor for amplifying an input signal and outputting the amplified signal, a first print circuit pattern for receiving the input signal and supplying the input signal to the transistor, a second print circuit pattern for supplying a supply voltage to the transistor, a ground terminal, and concentrated constant elements connected to the transistor on the multi-layer printed-circuit board is disclosed, wherein at least two layers of the multi-layer printed-circuit board are connected to the ground terminal, the first and second print circuit patterns are sandwiched on one layer of the multi-layer print circuit between the at least two layers, a first shielding circuit pattern, connected to the ground terminal, arranged around the first print circuit pattern on the one layer is further provided; and a second shielding circuit pattern, connected to the ground terminal, arranged around the second print circuit pattern on the one

Abstract: A power amplifier including an FET and a gate bias circuit having a variable resistor (VR) and a method of trimming the VR in the power amplifier are disclosed. The VR is trimmed to make the bias voltage to a pinch-off voltage of the FET. A first current in the pinch-off voltage condition from a bias supply voltage is measured. The VR is adjusted with a second current from the bias supply voltage measured. A difference between the first and second drain current values is calculated and a resistance of the VR is determined to make the difference within a reference. A second VR may be connected to the VR in parallel to make trimming the bias voltage easier or more accurately. The second VR may comprise a printed circuit pattern which shows 0.OMEGA. for the pinch-off condition and the printed circuit pattern also provides the infinite resistance when it is cut to adjust the VR. Another power amplifier including a memory and a D/A converter for generating the gate bias voltage is also disclosed.