Display device and input/output device

• US 10,521,032 B2
• Filed: 04/24/2015
• Issued: 12/31/2019
• Est. Priority Date: 05/02/2014
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Takahashi, Kei, Miyake, Hiroyuki
• Primary Examiner(s): Lee, Benjamin C
• Assistant Examiner(s): Neupane, Krishna P
• Application Number:
  US14/695,737
• Publication Number:
  US 20150317028A1
• Time in Patent Office: 1,712 Days
• Field of Search: None
• CPC Class Codes: G06F 2203/04102 Flexible digitiser, i.e. constructional details for allowing the whole digitising part of a device to be flexed or rolled like a sheet of paper
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• CPC Class Codes: G06F 3/04182 Filtering of noise external to the device and not generated by digitiser components
• CPC Class Codes: G06F 3/042 by opto-electronic means
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2300/0876 Supplementary capacities in pixels having special driving circuits and electrodes instead of being connected to common electrode or ground; Use of additional capacitively coupled compensation electrodes
• CPC Class Codes: G09G 2310/02 Addressing, scanning or driving the display screen or processing steps related thereto
• CPC Class Codes: G09G 2320/0295 by monitoring each display pixel
• CPC Class Codes: G09G 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 2380/02 Flexible displays
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element

Abstract

A circuit which detects an output current from a pixel and an output current from an input device, and converts the output current into data is provided. The current detection circuit includes an integrator circuit, a comparator, a counter, and a latch. The integrator circuit integrates the potential of a first signal during a period determined by a second signal and outputting it as a third signal. The comparator compares the potential of the third signal with a first potential and outputting a fourth signal. The counter outputs the number of pulses included in a fifth signal as a sixth signal during a period determined by the fourth signal. The latch holds the sixth signal. The integrator circuit preferably further includes an operational amplifier and some capacitors. The first signal is supplied from a pixel included in a display device or an input portion included in an input device.

Claims

1. An input/output device comprising:

a current detection circuit comprising an integrator circuit;

a display device; and

an input device,

wherein the integrator circuit comprises an operational amplifier, a first capacitor, a second capacitor, a first switch, a second switch, a third switch, and a fourth switch,

wherein a first electrode of the first capacitor is electrically connected to a first terminal of the operational amplifier,

wherein a second electrode of the first capacitor is electrically connected to a second terminal of the operational amplifier,

wherein a first terminal of the first switch is electrically connected to the first electrode of the first capacitor,

wherein a second terminal of the first switch is electrically connected to a first electrode of the second capacitor,

wherein a first terminal of the second switch is electrically connected to a second electrode of the second capacitor,

wherein a second terminal of the second switch is electrically connected to the second electrode of the first capacitor,

wherein a first terminal of the third switch is electrically connected to the display device,

wherein a second terminal of the third switch is electrically connected to the first terminal of the operational amplifier,

wherein a first terminal of the fourth switch is electrically connected to the input device,

wherein a second terminal of the fourth switch is electrically connected to the first terminal of the operational amplifier,

wherein the first switch, the second switch, and the fourth switch are turned off when the third switch is turned on, and

wherein the first switch, the second switch, and the fourth switch are turned on when the third switch is turned off.

2. The input/output device according to claim 1, wherein the current detection circuit further comprises a comparator, a counter and a latch.

3. The input/output device according to claim 1, wherein each of the first switch and the second switch is a transistor.

4. The input/output device according to claim 1,

wherein the integrator circuit further comprises a fifth switch comprising a first terminal and a second terminal,

wherein the first terminal of the fifth switch is electrically connected to the first terminal of the operational amplifier, the first electrode of the first capacitor, and the first terminal of the first switch, and

wherein the second terminal of the fifth switch is electrically connected to the second terminal of the operational amplifier, the second electrode of the first capacitor, and the second terminal of the second switch.

5. The input/output device according to claim 1, wherein a third terminal of the first switch is electrically connected to a third terminal of the second switch.

6. The input/output device according to claim 1,

wherein the display device comprises a pixel,

wherein the pixel comprises a transistor and a light emitting element,

wherein one of a source and a drain of the transistor is electrically connected to a power supply line, and

wherein the other of the source and the drain of the transistor is electrically connected to the light emitting element.