Display arrangement with backlight means

• US 6,621,482 B2
• Filed: 04/04/2001
• Issued: 09/16/2003
• Est. Priority Date: 05/15/2000
• Status: Expired due to Term

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Fuller, Bradley Joseph
• Primary Examiner(s): Shankar, Vijay
• Assistant Examiner(s): Patel, Nitin
• Application Number:
  US09/826,444
• Publication Number:
  US 20020171617A1
• Time in Patent Office: 895 Days
• Field of Search: 345/102, 345/211, 345/98, 345/87, 348/673, 348/575, 348/691
• US Class Current: 345/102
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336

Abstract

A transmissive display arrangement is provided comprising an array of cells, video controlling means, backlight means and backlight controlling means. The video s controlling means is configured to derive an adjusted video signal based on an initial video signal. The initial video signal represents a frame to be displayed by the display arrangement. The backlight means provides a backlight signal to the array in response to a backlight control signal. The backlight control signal is associated with the frame. The backlight controlling means is coupled to the video controller and derives the backlight control signal from the initial video signal and the adjusted video signal.

Claims

1. An apparatus, comprising:

a transmissive display arrangement including an array of cells;

video controlling means for deriving an adjusted video signal from an initial video signal representing a frame to be displayed by the display arrangement;

backlight means, coupled to the array of cells, for providing a backlight signal to the array in response to a backlight control signal associated with the frame;

backlight controlling means, coupled to the video controlling means and to the backlight means, for deriving the backlight control signal from the initial video signal and the adjusted video signal;

wherein the backlight controlling means is configured to further derive the backlight control signal from a maximum allowed value for the initial video signal and from a reference value of the initial video signal, said reference value being determined from a distribution property of the initial video signal.

2. The apparatus of claim 1, wherein the backlight controlling means is configured to further derive the backlight control signal based on an initial backlight control signal, the initial backlight control signal being obtained from a previous setting of the display arrangement.

3. The apparatus of claim 1, wherein the backlight controlling means is configured to derive the backlight control signal for each frame.

4. The apparatus of claim 1, further comprising:

memory means, coupled to the backlight controlling means, for storing a lookup table representative of a transmittance characteristic of a cell of the array;

wherein, the backlight controlling means is configured to further determine the backlight control signal based on the transmittance characteristic of the cell.

5. The apparatus of claim 1, wherein the video controlling means is configured to further derive the adjusted video signal based on a distribution property of the initial video signal.

6. The apparatus of claim 1, wherein the reference value is a maximum of the initial video signal.

7. The apparatus of claim 1, wherein for each cell of the array, the video controlling means is configured to derive a value of the adjusted video signal associated with the cell based on the reference value, the maximum allowed value, and a value of the initial video signal associated with the cell.

8. A transmissive display arrangement, comprising:

an array of cells;

video controlling means for deriving an adjusted video signal from an initial video signal representing a frame to be displayed by the display arrangement;

backlight means coupled to the array of cells, for providing a backlight signal to the array in response to a backlight control signal associated with the frame; and

backlight controlling means, coupled to the video controlling means and to the backlight means, for deriving the backlight control signal from the initial video signal and the adjusted video signal;

wherein the backlight controlling means is configured to further derive the backlight control signal from a maximum allowed value for the initial video signal and from a reference value of the initial video signal, said reference value being determined from a distribution property of the initial video signal.

9. The display arrangement of claim 8, wherein the backlight controlling means is configured to further derive the backlight control signal based on an initial backlight control signal, the initial backlight control signal being obtained from a previous setting of the display arrangement.

10. The display arrangement of claim 8, wherein the backlight controlling means is configured to derive the backlight control signal for each frame.

11. The display arrangement of claim 8, wherein

the array comprises a group of cells respectively including a color filter associated with a specific one of the three primary colors;

the backlight means comprises a set of LEDs configured to transmit a color-associated backlight signal of the specific primary color in response to a color-associated backlight control signal; and

,

the backlight controlling means is configured to derive the color-associated backlight control signal from values of the initial video signal associated with the group of cells and from values of the adjusted video signal associated with the group of cells.

12. A control circuit for a transmissive display arrangement, the control circuit comprising:

a video controlling means for deriving an adjusted video signal from an initial video signal representing a frame to be displayed by the display arrangement; and

a backlight controlling means, coupled to the video controlling means, for deriving a backlight control signal, associated with the frame, from the initial video signal and the adjusted video signal, the backlight control signal being for adjusting a backlight signal in the display arrangement;

wherein the backlight controlling means is configured to further derive the backlight control signal from a maximum allowed value for the initial video signal and from a reference value of the initial video signal, said reference value being determined from a distribution property of the initial video signal.

13. The control circuit of claim 12, wherein the backlight controlling means is configured to further derive the backlight control signal based on an initial backlight control signal, the initial backlight control signal being obtained from a previous setting of the display arrangement.

14. A computer readable storage medium for storing instructions for carrying out a method of adjusting a backlight signal in a transmissive display arrangement, the method comprising:

deriving an adjusted video signal from an initial video signal representing a frame to be displayed by the display arrangement; and

deriving a backlight control signal, associated with the frame, from the adjusted video signal, the initial video signal, a maximum allowed value for the initial video signal, and from a reference value of the initial video signal, said reference value being determined from a distribution property of the initial video signal, the backlight control signal being for adjusting the backlight signal.