Showing papers by "Jun Koyama published in 2016"
Patent•
01 Nov 2016
TL;DR: In this paper, the luminance of a light emitting element was controlled by means of controlling a current that flows to the TFT in a signal line drive circuit, and the current was held to a desired value without depending on the characteristics of TFT.
Abstract: By controlling the luminance of light emitting element not by means of a voltage to be impressed to the TFT but by means of controlling a current that flows to the TFT in a signal line drive circuit, the current that flows to the light emitting element is held to a desired value without depending on the characteristics of the TFT. Further, a voltage of inverted bias is impressed to the light emitting element every predetermined period. Since a multiplier effect is given by the two configurations described above, it is possible to prevent the luminance from deteriorating due to a deterioration of the organic luminescent layer, and further, it is possible to maintain the current that flows to the light emitting element to a desired value without depending on the characteristics of the TFT.
78 citations
TL;DR: In this paper, the authors demonstrate a 16-level cell using a nonvolatile oxide semiconductor random access memory test chip based on c-axis-aligned a-b-plane-anchored crystal In-Ga-Zn oxide (CAAC-IGZO) FETs.
Abstract: We demonstrate a 16-level cell using a nonvolatile oxide semiconductor random access memory test chip based on c-axis-aligned a–b-plane-anchored crystal In–Ga–Zn oxide (CAAC-IGZO) FETs. The memory cell consists of a CAAC-IGZO FET, a p-channel metal–oxide–semiconductor Si FET, and a cell capacitor. Data are written using a threshold voltage cancel write method, and a read circuit composed of voltage followers outputs a read voltage. Using a 200 ns write time of the test chip, the obtained maximum read voltage distribution width is 37 mV in the case of 32768 memory cells. The distributions of 16 read voltages are separated from each other without overlapping, with a single voltage follower exhibiting a maximum read voltage distribution width of 25.3 mV. In the −40 to 85 °C temperature range, the voltage distribution range is 0.13 V, and the variation due to varying temperatures is 0.24 mV/°C.
2 citations
Patent•
29 Mar 2016
TL;DR: In this article, an analog circuit is formed with the use of a thin film transistor including an oxide semiconductor which has a function as a channel formation layer, has a hydrogen concentration of 5×1019 atoms/cm3 or lower, and substantially functions as an insulator in the state where no electric field is generated.
Abstract: An object is to obtain a semiconductor device having a high sensitivity in detecting signals and a wide dynamic range, using a thin film transistor in which an oxide semiconductor layer is used. An analog circuit is formed with the use of a thin film transistor including an oxide semiconductor which has a function as a channel formation layer, has a hydrogen concentration of 5×1019 atoms/cm3 or lower, and substantially functions as an insulator in the state where no electric field is generated. Thus, a semiconductor device having a high sensitivity in detecting signals and a wide dynamic range can be obtained.
Patent•
12 Jan 2016
TL;DR: In this article, the authors proposed to reduce the off-state current of a thin-film transistor to suppress the leakage of electric charge stored in a capacitor, leading to a malfunction of the logic circuit.
Abstract: A logic circuit includes a thin film transistor having a channel formation region formed using an oxide semiconductor, and a capacitor having terminals one of which is brought into a floating state by turning off the thin film transistor. The oxide semiconductor has a hydrogen concentration of 5×1019 (atoms/cm3) or less and thus substantially serves as an insulator in a state where an electric field is not generated. Therefore, off-state current of a thin film transistor can be reduced, leading to suppressing the leakage of electric charge stored in a capacitor, through the thin film transistor. Accordingly, a malfunction of the logic circuit can be prevented. Further, the excessive amount of current which flows in the logic circuit can be reduced through the reduction of off-state current of the thin film transistor, resulting in low power consumption of the logic circuit.
Patent•
05 Oct 2016
TL;DR: In this article, the silicon nitride layer 910 formed by plasma CVD using a gas containing a hydrogen compound such as silane (SiH 4 ) and ammonia (NH 3 ) is provided on and in direct contact with the oxide semiconductor layer 905 used for the resistor 354, and the silicon oxide layer 909 serving as a barrier layer interposed therebetween.
Abstract: The silicon nitride layer 910 formed by plasma CVD using a gas containing a hydrogen compound such as silane (SiH 4 ) and ammonia (NH 3 ) is provided on and in direct contact with the oxide semiconductor layer 905 used for the resistor 354 , and the silicon nitride layer 910 is provided over the oxide semiconductor layer 906 used for the thin film transistor 355 with the silicon oxide layer 909 serving as a barrier layer interposed therebetween. Therefore, a higher concentration of hydrogen is introduced into the oxide semiconductor layer 905 than into the oxide semiconductor layer 906 . As a result, the resistance of the oxide semiconductor layer 905 used for the resistor 354 is made lower than that of the oxide semiconductor layer 906 used for the thin film transistor 355.
Patent•
19 Oct 2016
TL;DR: In this article, a driving circuit is formed by a resistance element and a thin-film transistor, and a semiconductor device is manufactured by using an oxide semiconductor layer in which electrical properties are controlled.
Abstract: Provided are a driving circuit which is formed by a resistance element and a thin film transistor which are manufactured by using an oxide semiconductor layer in which electrical properties are controlled, and a semiconductor device using the driving circuit A silicon nitride layer (910) is directly touched on the oxide semiconductor layer (905) applied to the resistance element (354) The silicon nitride layer (910) is formed by a plasma CVD with gases including a hydrogen compound such as SiH_4, NH_3, etc The silicon nitride layer (910) is formed on the oxide semiconductor layer (906) applied to a thin film transistor (355) A silicon oxide layer (909), which functions as a barrier layer, is formed between the silicon nitride layer (910) and the oxide semiconductor layer (906) High concentration of hydrogen, which is higher than the concentration of the oxide semiconductor layer (906), is applied to the oxide semiconductor layer (905) As a result, a resistance value of the oxide semiconductor layer applied to the resistance element is lower than a resistance value of the oxide semiconductor layer (906) applied to the thin film transistor (355)
Patent•
10 Nov 2016
TL;DR: In this paper, a display device consisting of a plurality of pixels including a first transistor, a second transistor, and an organic EL element was proposed to extend the service life of an EL element.
Abstract: PROBLEM TO BE SOLVED: To provide an EL display device capable of extending the service life of an EL elementSOLUTION: A display device comprises a plurality of pixels including a first transistor, a second transistor, and an organic EL element The display device performs gradation display by controlling a time during which the organic EL element emits light The organic EL element includes a pixel electrode and a counter electrode There is a period during which EL drive voltage of opposite polarity is applied to the organic EL elementSELECTED DRAWING: Figure 3
Patent•
09 Mar 2016
TL;DR: In this article, a power receiving device that, in a mobile electronic device, when charging a battery, simplifies charging from a power feeder that is power supply means, and prevents a fault due to an external factor of an external terminal, or damage to the external terminal itself, is provided.
Abstract: PROBLEM TO BE SOLVED: To provide a power receiving device that, in a mobile electronic device, when charging a battery, simplifies charging from a power feeder that is power supply means, and prevents a fault due to an external factor of an external terminal, or damage to the external terminal itself, which are caused by directly connecting the battery and the power feeder, and to provide an electronic apparatus including the power receiving deviceSOLUTION: An antenna circuit 102 and a booster antenna for supplying power to a mobile electronic device 100 are disposed The antenna circuit 102 receives a radio signal such as an electromagnetic wave via the booster antenna, and electric power that is obtained through the reception of the radio signal is supplied to the battery 104 through a signal processing circuit 103 to perform chargingSELECTED DRAWING: Figure 1
Patent•
21 Sep 2016
TL;DR: In this paper, the silicon nitride layer 910 formed by plasma CVD using a gas containing a hydrogen compound such as silane (SiH4) and ammonia (NH 3 ) is provided on and in direct contact with the oxide semiconductor layer 905 used for the resistor 354, and the silicon oxide layer 909 serving as a barrier layer interposed therebetween.
Abstract: The silicon nitride layer 910 formed by plasma CVD using a gas containing a hydrogen compound such as silane (SiH4) and ammonia (NH 3 ) is provided on and in direct contact with the oxide semiconductor layer 905 used for the resistor 354, and the silicon nitride layer 910 is provided over the oxide semiconductor layer 906 used for the thin film transistor 355 with the silicon oxide layer 909 serving as a barrier layer interposed therebetween. Therefore, a higher concentration of hydrogen is introduced into the oxide semiconductor layer 905 than into the oxide semiconductor layer 906. As a result, the resistance of the oxide semiconductor layer 905 used for the resistor 354 is made lower than that of the oxide semiconductor layer 906 used for the thin film transistor 355.