Image display apparatus and image display method

• US 20040201561A1
• Filed: 05/04/2004
• Published: 10/14/2004
• Est. Priority Date: 05/10/1999
• Status: Active Grant

• Current Assignee: Katsuyuki Arimoto, Takahiro Kobayashi, Taro Funamoto, Wataru Machidori, Yoshihito Ota
• Original Assignee: Katsuyuki Arimoto, Takahiro Kobayashi, Taro Funamoto, Wataru Machidori, Yoshihito Ota
• Inventors: Kobayashi, Takahiro, Ota, Yoshihito, Arimoto, Katsuyuki, Funamoto, Taro, Machidori, Wataru
• Granted Patent: US 7,265,743 B2
• Time in Patent Office: Days
• US Class Current: 345/89
• CPC Class Codes: G06F 3/14 Digital output to display device ; Cooperation and interconnection of the display device with other functional units
• CPC Class Codes: G09G 2320/0238 Improving the black level
• CPC Class Codes: G09G 2320/0247 Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
• CPC Class Codes: G09G 2320/0271 Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping
• CPC Class Codes: G09G 2320/0276 for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction
• 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 2320/0653 Controlling or limiting the speed of brightness adjustment of the illumination source
• CPC Class Codes: G09G 2320/066 for control of contrast
• CPC Class Codes: G09G 2320/103 Detection of image changes, e.g. determination of an index representative of the image change
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2340/10 Mixing of images, i.e. displayed pixel being the result of an operation, e.g. adding, on the corresponding input pixels
• CPC Class Codes: G09G 2360/145 the light originating from the display screen
• 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
• CPC Class Codes: G09G 3/3426 the different display panel areas being distributed in two dimensions, e.g. matrix
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers

Abstract

Provided are an image display apparatus and method capable of visually improving a sense of contrast by adjusting contrast and a light source to have correlation. A characteristics detection part 11 detects MAX, MIN, and APL of an input signal. A control data generation part 12 calculates Gain for amplifying a difference between MAX and MIN to a width of a dynamic range and Offset indicating the DC level to be shifted so that the input video signal amplified by Gain falls with in the output dynamic range of a DC level adjustment part 13B. A signal amplitude adjustment part 13A amplifies the input video signal with reference to APL and in accordance with Gain. The DC level adjustment part 13B shifts the DC level of the amplified input video signal in accordance with a value of Offset. A light source control part 16 controls a light source 18 so that a visual brightness level on a screen is equal to a brightness level of the input video signal.

Claims

1-40. -40 (Cancelled)

41. An image display apparatus displaying an image on a passive light modulation part including a light source, the apparatus comprising:

a video signal input part inputting a video signal; and

a light source control part controlling a brightness of said light source, wherein

said video signal input part and said light source control part are connected to each other via a high-pass filter.

42. The image display apparatus according to claim 41, wherein a signal to be inputted to said high-pass filter is generated in accordance with said video signal.

43. An image display apparatus displaying an image on a passive light modulation part including a light source, the apparatus comprising:

a high-pass filter to which a signal for dynamically controlling a brightness of said light source is inputted;

an addition part adding a signal outputted from said high-pass filter to a reference light adjustment control signal generated based on the light-emitting efficiency of said light source; and

a light source control section controlling the brightness of said light source in accordance with a signal outputted from said addition part.

44. The image display apparatus according to claim 43, wherein a signal to be inputted to said high-pass filter is generated in accordance with said video signal.

45. An image display apparatus displaying an image on a passive light modulation part including a light source, the apparatus comprising:

a high-pass filter to which a signal for controlling a brightness of said light source is inputted;

an addition part adding a reference light adjustment control signal with a fixed value to a signal outputted from said high-pass filter; and

a light source control section controlling the brightness of said light source in accordance with a signal outputted from said addition part, wherein

said reference light adjustment control signal is determined such that when a signal identical to said reference light adjustment control signal is outputted from said addition part, the light-emitting efficiency of said light source becomes maximum.

46. The image display apparatus according to claim 45, further comprising:

a control data generation part generating a signal for controlling the brightness of said light source, in accordance with a video signal to be inputted to said image display apparatus.

47. An image display method of displaying an image on a passive light modulation part including a light source, the method comprising:

a video signal input step of inputting a video signal;

a light source control step of controlling a brightness of said light source, and

a low frequency removing step of removing low frequency components, between said video signal input step and said light source control step.

48. The image display method according to claim 47, wherein in said low frequency removing step, the low frequency components of a signal generated in accordance with said video signal is removed.

49. An image display method of displaying an image on a passive light modulation part including a light source, the method comprising:

a low frequency removing step of removing low frequency components of a signal for dynamically controlling a brightness of said light source;

an addition step of adding a signal obtained as a result of said low frequency removing step to a reference light adjustment control signal generated based on the light-emitting efficiency of said light source; and

a light source control step of controlling the brightness of said light source in accordance with a signal obtained as a result of said addition step.

50. The image display method according to claim 49, wherein in said low frequency removing step, the low frequency components of a signal generated in accordance with said video signal is removed.

51. An image display method of displaying an image on a passive light modulation part including a light source, the method comprising:

a low frequency removing step of removing low frequency components of a signal for controlling a brightness of said light source;

an addition step of adding a reference light adjustment control signal with a fixed value to a signal obtained as a result of said low frequency removing step; and

a light source control step of controlling the brightness of said light source in accordance with a signal obtained as a result of said addition step, wherein

said reference light adjustment control signal is determined such that when a signal identical to said reference light adjustment control signal is obtained as a result of said addition step, the light-emitting efficiency of said light source becomes maximum.

52. The image display method according to claim 51, further comprising:

a control data generation step of generating a signal for controlling the brightness of said light source, in accordance with a video signal to be inputted.