Display device, and method of operation thereof

• US 20060158458A1
• Filed: 12/02/2005
• Published: 07/20/2006
• Est. Priority Date: 12/22/2004
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Tanada, Yoshifumi, Yamazaki, Shunpei, Tachimura, Yuko, Kojima, Yu
• Granted Patent: US 8,319,714 B2
• Time in Patent Office: Days
• US Class Current: 345/592
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side
• CPC Class Codes: G09G 2300/06 Passive matrix structure, i.e. with direct application of both column and row voltages to the light emitting or modulating elements, other than LCD or OLED
• CPC Class Codes: G09G 2300/0809 Several active elements per pixel in active matrix panels
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2300/0847 being a dynamic memory without any storage capacitor, i.e. with use of parasitic capacitances as storage elements
• 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 2310/0251 Precharge or discharge of pixel before applying new pixel voltage
• 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 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/3216 using a passive matrix
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 5/02 characterised by the way in which colour is displayed details of colour display specific for CRTs G09G1/28; specific for flat matrix panels other than liquid crystal displays G09G3/2003; specific for liquid crystal displays G09G3/3607

Abstract

It is an object of the invention to provide a display device which performs high grayscale display in accordance with display contents and a game machine with an improved realistic sensation. The invention is a display device characterized by including a pixel portion which performs display based on a video signal and a driver circuit portion inputted with the video signal, wherein the driver circuit portion has a unit for controlling a grayscale in accordance with display of the pixel portion. In a liquid crystal display device, luminance of a lighting unit is controlled based on a signal from the unit for controlling a grayscale whereas a current supplied to a light emitting element is controlled in a light emitting device. By applying such a display device to a game machine, a realistic sensation can be improved.

Claims

1. A display device comprising:

a pixel portion which performs display based on a video signal; and

a driver circuit portion inputted with the video signal,

wherein the driver circuit portion includes a unit for controlling a grayscale so that a highest grayscale is different in accordance with display of the pixel portion.

6. A game machine using the display device according to any one of claims 1 to 5.

2. A display device comprising:

a pixel portion including a light emitting element which performs display based on a video signal; and

a driver circuit portion inputted with the video signal,

wherein the driver circuit portion includes a circuit for controlling a grayscale of the video signal so that a highest grayscale is different in accordance with display of the pixel portion.

3. A display device comprising:

a pixel portion which performs display based on a video signal;

a lighting unit which supplies light to the pixel portion; and

a driver circuit portion which is inputted with the video signal and controls the lighting unit,

wherein the driver circuit portion includes a circuit for controlling light emission intensity of the lighting unit so that a highest grayscale is different in accordance with display of the pixel portion.

4. A display device comprising:

a pixel portion including a light emitting element which performs display based on a video signal; and

a driver circuit portion inputted with the video signal,

wherein the driver circuit portion includes a control circuit which controls light emission intensity of the light emitting element in accordance with display of a first region of the pixel portion and controls light emission intensity of the light emitting element in accordance with display of a second region; and

wherein a highest grayscale is different between the first region and the second region.

5. A display device comprising:

a pixel portion which performs display based on a video signal;

a lighting unit which supplies light to the pixel portion; and

a driver circuit portion which is inputted with the video signal and controls the lighting unit,

wherein the driver circuit portion includes a control circuit which controls light emission intensity of the lighting unit in accordance with display of a first region of the pixel portion and controls an alignment of the liquid crystal in accordance with display of a second region; and

wherein a highest grayscale is different between the first region and the second region.

7. An operating method of a display device comprising:

a pixel portion which performs display based on a video signal;

a driver circuit portion where the video signal is to be inputted; and

a control circuit for controlling a grayscale in accordance with display of the pixel portion in the driver circuit portion,

wherein the video signal is inputted to a frame memory included in the control circuit and the video signal for one frame is stored in the frame memory;

carrying out a process to determine a ratio of a high grayscale region to a low grayscale region based on the video signal by a determining circuit included in the control circuit; and

carrying out an addition process by a converter circuit included in the control circuit to display a high grayscale region at higher luminance based on a result of the determination process.

8. An operating method of a display device comprising:

a pixel portion which performs display based on a video signal;

a driver circuit portion inputted with the video signal; and

a control circuit for controlling a grayscale in accordance with display of the pixel portion in the driver circuit portion,

wherein the video signal is inputted to a frame memory included in the control circuit and a video signal for one frame is stored in the frame memory,

carrying out a process to determine a ratio of a high grayscale region to a low grayscale region based on the video signal by a determining circuit included in the control circuit; and

carrying out a subtraction process by a converter circuit included in the control circuit to decrease luminance of a whole screen based on a result of the determination process.