Method for driving liquid crystal display assembly

• US 20070247415A1
• Filed: 04/12/2007
• Published: 10/25/2007
• Est. Priority Date: 04/19/2006
• Status: Active Grant

• Current Assignee: Saturn Licensing LLC (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Yasunaga, Hiroaki
• Granted Patent: US 7,847,784 B2
• Time in Patent Office: Days
• US Class Current: 345/102
• CPC Class Codes: G09G 2320/0247 Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
• CPC Class Codes: G09G 2320/0252 Improving the response speed
• 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 3/3413 Details of control of colour illumination sources

Abstract

A method driving an LCD assembly, the LCD assembly including a transmission-type LCD including a display area configured of pixels, a planar-light-source device illuminating the display area, and a driving circuit driving the planar-light-source device and LCD; wherein the driving circuit supplies a control signal controlling the optical transmittance of each pixel to each pixel, the method comprising, for each frame with LCD image display, the steps of: controlling the luminance of the planar-light-source device by the driving circuit such that, when assuming that the control signal equivalent to a driving signal having the maximum value of driving signals input to the driving circuit driving all the pixels making up the display area is supplied to a pixel, the luminance of the pixel is obtained; and controlling the luminance of the planar-light-source device by the driving circuit based on the response speed of a liquid-crystal material making up the pixels.

Claims

1. A method for driving a liquid crystal display assembly, said liquid crystal display assembly including

a transmission-type liquid crystal display including a display area made up of pixels arrayed in a two-dimensional matrix form,

a planar light source device illuminating said display area from the back, and

a driving circuit for driving said planar light source device and said liquid crystal display,

wherein a control signal for controlling the optical transmittance of each of said pixels is supplied to each of said pixels from said driving circuit;

said method comprising, for each frame with image display of said liquid crystal display, the steps of;

controlling the luminance of said planar light source device by said driving circuit such that, when assuming that said control signal equivalent to a driving signal having a value equivalent to an intra-frame driving signal maximum value X_F-max which is the maximum value of the values of driving signals that are input to said driving circuit for driving all of said pixels making up said display area is supplied to a pixel, the luminance of said pixel is obtained; and

controlling the luminance of said planar light source device by said driving circuit based on the response speed of a liquid crystal material making up said pixels.

2. The method for driving a liquid crystal display assembly according to claim 1, wherein each of said pixels is configured with multiple sub pixels as a set each of which emits light having a different color;

and wherein said control signal for controlling the optical transmittance of each of said sub pixels is supplied from said driving circuit to each of said sub pixels making up each of said pixels.

3. The method for driving a liquid crystal display assembly according to claim 1, wherein a light source making up said planar light source device is made up of a light emitting diode driven based on pulse-width modulation;

and

wherein, when assuming that the number of the unit luminescence periods of said light emitting diode in one frame is K, a duty ratio in driving based on the pulse-width modulation of said light emitting diode during the k′

th unit luminescence period (wherein k=1, 2, 3, and so on through K) is controlled, thereby controlling the luminance of said planar light source device based on the response speed of said liquid crystal material making up said pixels.

4. A method for driving a liquid crystal display assembly, said liquid crystal display assembly including

a transmission-type liquid crystal display including a display area made up of pixels arrayed in a two-dimensional matrix form, which is subjected to line sequential driving,

a planar light source device which is made up of, when assuming that said display area of said liquid crystal display are divided into P×

Q virtual display area units, P×

Q planar light source units corresponding to said P×

Q display area units, with each of said planar light source units illuminating the display area unit corresponding thereto from the back, and

a driving circuit for driving said planar light source device and said liquid crystal display,

wherein a control signal for controlling the optical transmittance of each of said pixels is supplied to each of said pixels from said driving circuit,

said method comprising, for each frame with image display of said liquid crystal display, the steps of;

controlling the luminance of said planar light source unit by said driving circuit such that, when assuming that said control signal equivalent to a driving signal having a value equivalent to an intra-frame driving signal maximum value X_F-max which is the maximum value of the values of driving signals that are input to said driving circuit for driving all of said pixels making up said display area is supplied to a pixel, the luminance of said pixel is obtained;

controlling the luminance of said planar light source unit by said driving circuit based on the response speed of a liquid crystal material making up said pixels; and

controlling the light emitting start period of each of said planar light source units by said driving circuit depending on the disposed position of each of said planar light source units.

5. The method for driving a liquid crystal display assembly according to claim 4, wherein each of said pixels is configured with multiple sub pixels as a set each of which emits light having a different color;

and

wherein said control signal for controlling the optical transmittance of each of said sub pixels is supplied from said driving circuit to each of said sub pixels making up each of said pixels.

6. The method for driving a liquid crystal display assembly according to claim 4, wherein a light source making up said planar light source unit is made up of a light emitting diode driven based on pulse-width modulation;

and

wherein, when assuming that the number of the unit luminescence periods of said light emitting diode in one frame is K, a duty ratio in driving based on the pulse-width modulation of said light emitting diode during the k′

th unit luminescence period (wherein k=1, 2, 3, and so on through K) is controlled, thereby controlling the luminance of said planar light source unit based on the response speed of said liquid crystal material making up said pixels.

7. A method for driving a liquid crystal display assembly, said liquid crystal display assembly including

a transmission-type liquid crystal display including a display area made up of pixels arrayed in a two-dimensional matrix form, which is subjected to line sequential driving,

a planar light source device which is made up of, when assuming that said display area of said liquid crystal display are divided into P×

Q virtual display area units, P×

Q planar light source units corresponding to said P×

Q display area units, with each of said planar light source units illuminating the display area unit corresponding thereto from the back, and

a driving circuit for driving said planar light source device and said liquid crystal display;

wherein a control signal for controlling the optical transmittance of each of said pixels is supplied to each of said pixels from said driving circuit; and

wherein for each frame with image display of said liquid crystal display said method includes the steps of;

controlling the luminance of said planar light source unit corresponding to said display unit by said driving circuit with each of said planar light source units such that, when assuming that said control signal equivalent to a driving signal having a value equivalent to an intra-display-area-unit driving signal maximum value X_U-max which is the maximum value of the values of driving signals that are input to said driving circuit for driving all of said pixels making up said display area is supplied to a pixel, the luminance of said pixel is obtained, and

controlling the luminance of said planar light source unit by said driving circuit based on the response speed of a liquid crystal material making up said pixels.

8. The method for driving a liquid crystal display assembly according to claim 7, for each frame with image display of said liquid crystal display, further including the step of:

controlling the light emitting start period of each of said planar light source units by said driving circuit depending on the disposed position of each of said planar light source units.

9. The method for driving a liquid crystal display assembly according to claim 7, wherein each of said pixels is configured with multiple sub pixels as a set each of which emits light having a different color;

and

wherein said control signal for controlling the optical transmittance of each of said sub pixels is supplied from said driving circuit to each of said sub pixels making up each of said pixels.

10. The method for driving a liquid crystal display assembly according to claim 7, wherein a light source making up said planar light source unit is made up of a light emitting diode driven based on pulse-width modulation;

and

wherein, when assuming that the number of the unit luminescence periods of said light emitting diode in one frame is K, a duty ratio in driving based on the pulse-width modulation of said light emitting diode during the k′

th unit luminescence period (wherein k=1, 2, 3, and so on through K) is controlled, thereby controlling the luminance of said planar light source unit based on the response speed of said liquid crystal material making up said pixels.

11. The method for driving a liquid crystal display assembly according to claim 10, wherein the value of K is an integral multiple of the value of Q.