Image display device

• US 6,950,081 B2
• Filed: 08/06/2002
• Issued: 09/27/2005
• Est. Priority Date: 10/10/2001
• Status: Expired due to Term

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Hitachi, Ltd.
• Inventors: Akimoto, Hajime, Shiba, Takeo, Nishitani, Shigeyuki, Mikami, Yoshirou, Kinugawa, Kiyoshige
• Primary Examiner(s): Shankar, Vijay
• Assistant Examiner(s): Patel, Nitin
• Application Number:
  US10/212,046
• Publication Number:
  US 20030067424A1
• Time in Patent Office: 1,148 Days
• Field of Search: 345/55, 345/53, 345/77, 345/87, 345/88, 345/92, 345/93, 345/94, 345/97, 345/98, 345/99, 345/100, 345/80, 345/82, 345/83, 345/84, 345/90, 345/204, 340/782, 340/762, 315/169.3, 315/169.1
• US Class Current: 345/55
• CPC Class Codes: G09G 2300/0408 Integration of the drivers onto the display substrate
• CPC Class Codes: G09G 2300/0417 Special arrangements specific to the use of low carrier mobility technology
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• CPC Class Codes: G09G 2300/0439 Pixel structures
• CPC Class Codes: G09G 2300/0809 Several active elements per pixel in active matrix panels
• CPC Class Codes: G09G 2300/0819 used for counteracting undesired variations, e.g. feedback or autozeroing
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2300/0852 being a dynamic memory with more than 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 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 2310/027 Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters
• CPC Class Codes: G09G 2310/062 Waveforms for resetting a plurality of scan lines at a time
• CPC Class Codes: G09G 2310/065 Waveforms comprising zero voltage phase or pause
• CPC Class Codes: G09G 2310/066 Waveforms comprising a gently increasing or decreasing portion, e.g. ramp
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/0242 Compensation of deficiencies in the appearance of colours
• CPC Class Codes: G09G 2320/0257 Reduction of after-image effects
• CPC Class Codes: G09G 2320/0261 in the context of movement of objects on the screen or movement of the observer relative to the screen
• CPC Class Codes: G09G 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 3/2014 : by modulation of the duration of a single pulse during which the logic level remains constant
• CPC Class Codes: G09G 3/32 : semiconductive, e.g. using light-emitting diodes [LED]
• CPC Class Codes: G09G 3/3208 : organic, e.g. using organic light-emitting diodes [OLED]
• CPC Class Codes: G09G 3/3233 : with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: G09G 3/3258 : with pixel circuitry controlling the voltage across the light-emitting element
• 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
• CPC Class Codes: G09G 3/3291 : in which the data driver supplies a variable data voltage for setting the current through, or the voltage across, the light-emitting elements
• CPC Class Codes: G09G 5/10 : Intensity circuits
• CPC Class Codes: G09G 5/18 : Timing circuits for raster scan displays specially adapted for television H04N ; synchronisation between the display unit and other display units, videodisc player G09G5/12

Abstract

The invention provides an image display device that has an especially satisfactory display quality for animated images, and sufficiently suppresses the irregularities of display quality among pixels. The image display device includes a light emitting drive means that drives a light emitting means, based on an analog display signal inputted to the pixels, and a light emitting control switch for controlling a light-on or light-off of the light emitting means on one end of the light emitting drive means in each pixel.

Claims

1. An image display device comprising:

a display unit composed of plural pixels each having a light emitting means;

a signal line for inputting an analog display signal to the pixels; and

a light emitting drive means for driving the light emitting means based on the analog display signal inputted to the pixels through the signal line, wherein

the light emitting drive means provided for each of the pixels is a field effect transistor,

the signal line is connected to a gate of the field effect transistor through at least one capacitance means,

one of a source or a drain of the field effect transistor is connected to a power supply means, the other of the source and the drain is connected to the light emitting means, and at least one of the source and the drain is connected via a first switch to the power supply means or the light emitting means, and

the field effect transistor is constructed to apply one of the analog display signal and a virtually triangular pulse signal to the gate thereof through the capacitance means.

2. An image display device as claimed in claim 1, wherein the light emitting means is an organic light emitting diode.

3. An image display device as claimed in claim 1, wherein the light emitting drive means and the light emitting control switch means are polycrystalline silicon thin film transistors provided on a transparent substrate.

4. An image display device as claimed in claim 1, wherein a second switch is provided between the gate and the drain of the field effect transistor, while the first switch is provided between the drain and the light emitting means.

5. An image display device as claimed in claim 4, wherein the field effect transistor, the first switch, and the second switch are TFTs of the same conductivity type.

6. An image display device as claimed in claim 4, wherein the light-on and the light-off are alternated by alternating the first switch and the second switch.

7. An image display device as claimed in claim 4, wherein the first switch and the second switch are a drive switch and signal input switch.

8. An image display device as claimed in claim 1, wherein both the analog display signal and the virtually triangular pulse signal are generated by a common DA converter.

9. An image display device as claimed in claim 8, wherein the DA converter is composed of polycrystalline silicon thin film transistors.

10. An image display device comprising:

a display unit composed of plural pixels each having a light emitting means;

a signal line for inputting an analog display signal to the pixels;

a light emitting drive means for driving the light emitting means based on the analog display signal inputted to the pixels through the signal line; and

a light emitting control switch means for controlling a light-on or a light-off of the light emitting means during image-displaying,

wherein the light emitting means in each pixel connected to one end of the light emitting drive means, and

wherein a time period ratio of the light-on and the light-off ranges from 1;

9 to 9;

1.

11. An animation display device comprising:

an image display device including;

a display unit composed of plural pixels each having a light emitting means;

a signal line for inputting an analog display signal to the pixels;

a light emitting drive means for driving the light emitting means based on the analog display signal inputted to the pixels through the signal line; and

a light emitting control switch means for controlling a light-on or a light-off of the light emitting means during image-displaying, the light emitting means in each pixel connected to one end of the light emitting drive means;

an input interface circuit for receiving animated image data;

a microprocessor for decoding the animated image data;

a display panel controller incorporating a DA converter;

a triangular pulse generation circuit;

a first battery and a secondary battery; and

a frame memory.