Abstract: A display device in which power consumed in an image holding period is suppressed. The display device includes a liquid crystal display panel which is driven by power supplied from a converter or a backup circuit. A fixed potential may be supplied and a capacitor may be charged with the use of the converter in a writing operation where a load is large, and the fixed potential may be preferentially supplied from the capacitor without using the converter in an image holding period when the load is small.

Abstract: An electronic device of a novel embodiment, specifically an arm-worn electronic device used while being worn on an arm, is provided. An arm-worn secondary battery used while being worn on an arm is provided. An electronic device is provided, which includes a structure body having a curved surface as a support structure body, a flexible secondary battery including a film as an exterior body over the curved surface of the support structure body, and a display portion including a plurality of display elements between a pair of films over the secondary battery. The plurality of display elements and the secondary battery overlap with each other at least partly. It is possible to provide an electronic device which has a small maximum thickness of 1 cm or less and a light weight of 50 g or less even when an arm-worn secondary battery is provided with a display portion.

Abstract: A substrate cooling method is for, using a load-lock mechanism for controlling a pressure therein between a first pressure close to an atmospheric pressure and a second pressure in a vacuum state, cooling a substrate transferred from the second module to the first module. The method includes maintaining a pressure in the chamber to the second pressure, allowing the chamber to communicate with a second module, and loading the substrate into the chamber; locating the substrate to a cooling position close to the cooling member; exhausting the chamber such that the pressure in the chamber becomes a third pressure where a region between a surface of the cooling member and a backside of the substrate satisfies a molecular flow condition. The method further includes introducing a purge gas into the chamber to increase the pressure in the chamber to the first pressure, and cooling the substrate by the cooling member.

Abstract: To suppress a loss of data in a semiconductor device. To provide a display device including a capacitor storing data, a display element performing display in accordance with the data, and switching elements connected to electrodes of the capacitor. In the display device, the voltage is held between the electrodes of the capacitor by turning the switching elements off; thus, the data can be stored even when supplying the power supply is stopped.

Abstract: A resonant power feeding system that can provide high power transmission efficiency between a power feeding device and a power reception device without dynamically controlling the oscillation frequency in accordance with the distance between the power feeding device and the power reception device. High power transmission efficiency between the power feeding device and the power reception device is obtained by addition of a structure for adjusting the matching condition to both the power reception device and the power feeding device. Specifically, a transmission-reception circuit and a matching circuit are provided in both the power reception device and the power feeding device, and wireless signals for adjusting the matching circuit are transmitted and received through a resonant coil. Thus, the power feeding device can efficiently supply power to the power reception device without adjusting the oscillation frequency.

Abstract: A wireless power feeding system includes a power feeding device and a power receiving device. The power feeding device includes a first resonance coil connected to a high-frequency power source through a first matching circuit, and a first control circuit connected to the first matching circuit and a first transmitter-receiver circuit. The power receiving device includes a second resonance coil configured to be in magnetic resonance with the first resonance coil, and a second control circuit connected to a load, a second matching circuit, and a second transmitter-receiver circuit.

Abstract: A resonant power feeding system that can provide high power transmission efficiency between a power feeding device and a power reception device without dynamically controlling the oscillation frequency in accordance with the distance between the power feeding device and the power reception device. High power transmission efficiency between the power feeding device and the power reception device is obtained by addition of a structure for adjusting the matching condition to both the power reception device and the power feeding device. Specifically, a transmission-reception circuit and a matching circuit are provided in both the power reception device and the power feeding device, and wireless signals for adjusting the matching circuit are transmitted and received through a resonant coil. Thus, the power feeding device can efficiently supply power to the power reception device without adjusting the oscillation frequency.

Abstract: To suppress a loss of data in a semiconductor device. To provide a display device including a capacitor storing data, a display element performing display in accordance with the data, and switching elements connected to electrodes of the capacitor. In the display device, the voltage is held between the electrodes of the capacitor by turning the switching elements off; thus, the data can be stored even when supplying the power supply is stopped.

Abstract: An electronic device of a novel embodiment, specifically an arm-worn electronic device used while being worn on an arm, is provided. An arm-worn secondary battery used while being worn on an arm is provided. An electronic device is provided, which includes a structure body having a curved surface as a support structure body, a flexible secondary battery including a film as an exterior body over the curved surface of the support structure body, and a display portion including a plurality of display elements between a pair of films over the secondary battery. The plurality of display elements and the secondary battery overlap with each other at least partly. It is possible to provide an electronic device which has a small maximum thickness of 1 cm or less and a light weight of 50 g or less even when an arm-worn secondary battery is provided with a display portion.

Abstract: A resonant power feeding system that can provide high power transmission efficiency between a power feeding device and a power reception device without dynamically controlling the oscillation frequency in accordance with the distance between the power feeding device and the power reception device. High power transmission efficiency between the power feeding device and the power reception device is obtained by addition of a structure for adjusting the matching condition to both the power reception device and the power feeding device. Specifically, a transmission-reception circuit and a matching circuit are provided in both the power reception device and the power feeding device, and wireless signals for adjusting the matching circuit are transmitted and received through a resonant coil. Thus, the power feeding device can efficiently supply power to the power reception device without adjusting the oscillation frequency.

Abstract: A wireless power feeding system includes a power feeding device and a power receiving device. The power feeding device includes a first resonance coil connected to a high-frequency power source through a first matching circuit, and a first control circuit connected to the first matching circuit and a first transmitter-receiver circuit. The power receiving device includes a second resonance coil configured to be in magnetic resonance with the first resonance coil, and a second control circuit connected to a load, a second matching circuit, and a second transmitter-receiver circuit.

Abstract: A display device in which power consumed in an image holding period is suppressed. The display device includes a liquid crystal display panel which is driven by power supplied from a converter or a backup circuit. A fixed potential may be supplied and a capacitor may be charged with the use of the converter in a writing operation where a load is large, and the fixed potential may be preferentially supplied from the capacitor without using the converter in an image holding period when the load is small.