Driver with driving current interruption

• US 7,817,114 B2
• Filed: 11/23/2004
• Issued: 10/19/2010
• Est. Priority Date: 12/04/2003
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Yamashita, Takanori, Kawano, Fujio, Kawasaki, Somei, Iseki, Masami
• Primary Examiner(s): Mengistu; Amare
• Assistant Examiner(s): ZUBAJLO, JENNIFER L
• Application Number:
  US10/994,310
• Publication Number:
  US 20050122150A1
• Time in Patent Office: 2,156 Days
• Field of Search: 345 76- 83, 315/169.3, 313/463, 313/504
• US Class Current: 345/76
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2300/0861 with additional control of the display period without amending the charge stored in a pixel memory, e.g. by means of additional select electrodes
• CPC Class Codes: G09G 2310/0289 Details of voltage level shifters arranged for use in a driving circuit
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2330/026 Arrangements or methods related to booting a display
• CPC Class Codes: G09G 2330/045 Protection against panel overheating
• CPC Class Codes: G09G 3/3241 the current through the light-emitting element being set using a data current provided by the data driver, e.g. by using a two-transistor current mirror
• CPC Class Codes: G09G 3/325 the data current flowing through the driving transistor during a setting phase, e.g. by using a switch for connecting the driving transistor to the data driver
• CPC Class Codes: G09G 3/3266 Details of drivers for scan electrodes
• CPC Class Codes: G09G 3/3283 in which the data driver supplies a variable data current for setting the current through, or the voltage across, the light-emitting elements

Abstract

A display apparatus includes a plurality of pixel circuits, wherein each of the pixel circuits comprises a light emitting element, a drive transistor for supplying the light emitting element with a current, as a driving current, of a quantity corresponding to a potential between a gate and a source of the drive transistor, a first switch for controlling a flow of the current supplied to the light emitting element, a second switch for switching between a first state of setting the potential between the gate and the source of the drive transistor and a second state of holding the potential between the gate and the source of the drive transistor, and a circuit for supplying the first switch with a signal for switching a state of controlling the flowing of the current of the driving current. In addition, a circuit supplies the second switch with a signal for switching the second switch between the first and second states, and a circuit sets the potential between the gate and the source of the driving transistor at a potential to flow the driving current so as to set the light emitting element at a low level driving state, at a time of starting a power source or a waiting state of the power source, and under a state that the first switch suppresses the flowing of the driving current and the second switch is at the first state.

Claims

1. A display apparatus comprising:

a plurality of pixel circuits arranged in a matrix, wherein each of the pixel circuits comprises;

a light emitting element;

a drive transistor for supplying the light emitting element with a drive current of a quantity corresponding to a gate potential of the drive transistor;

a first switch for switching between a first drive state of shutting off the drive current to the light emitting element and a second drive state of flowing the drive current to the light emitting element to control a flow of the drive current supplied to the light emitting element;

a second switch for switching between a first scan state of setting the gate potential of the drive transistor and a second scan state of keeping the set gate potential of the drive transistor;

a row drive circuit for generating, in response to a clock of an active matrix display operation, a first scan line signal to be applied to the first switch through a scan line so that the first switch switches between the first and second drive states, and a second scan line signal to be applied to the second switch through the scan line so that the second switch switches between the first and second scan states; and

a column drive circuit for generating, in response to an image signal, a data signal to be applied to each of the pixel circuits through a data line,

wherein said row drive circuit applies, in response to turn-on of a power source or start of a waiting state, a switch control signal to the first and second switches for all of the pixel circuits through the scan line for a predetermined interval after the turn-on of the power source or a waiting state interval, as a priority signal to the first and second scan signals so that, for all of the pixel circuits, the first switch becomes the first drive state and the second switch becomes the first scan state for the predetermined interval or the waiting state interval, and

wherein the column drive circuit shuts off the data signal or applies a predetermined low level signal on the data line for all of the pixel circuits during the predetermined interval after the turn-on of the power source or the waiting state interval and prior to a normal display drive period.

2. A display apparatus according to claim 1, wherein each of the pixel circuits further comprises a third switch connected to the data line, with the first scan line signal applied to the third switch through the scan line so that the data signal is applied to the drive transistor and the second switch during the first drive state.