Image displaying apparatus

• US 20070103418A1
• Filed: 10/26/2006
• Published: 05/10/2007
• Est. Priority Date: 11/09/2005
• Status: Abandoned Application

• Current Assignee: Hitachi Displays Limited (Japan Display Incorporated)
• Original Assignee: Hitachi Displays Limited (Japan Display Incorporated)
• Inventors: Ono, Kikuo, Kabuto, Nobuaki, Ooishi, Yoshihisa, Ogino, Masahiro, Mori, Ikuko
• Application Number:
  US11/586,543
• Publication Number:
  US 20070103418A1
• Time in Patent Office: Days
• US Class Current: 345/89
• CPC Class Codes: G09G 2310/061 for resetting or blanking
• 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 2320/0271 Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping
• CPC Class Codes: G09G 2320/0633 by amplitude modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2320/064 by time modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2340/0435 Change or adaptation of the frame rate of the video stream
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/2025 the sub-frames having all the same time duration
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers

Abstract

An image displaying apparatus, for improving motion blur, in particular, on an image displaying apparatus of hold-type, such as, a liquid crystal display element, etc., comprising: sub-frame producing portions (5, 6) for producing a first sub-frame, a second sub-frame being lower in the gradation than the first sub-frame, from an image of one (1) frame of an image signal inputted; a histogram detection portion (2) for detecting brightness histogram of the image signal; an image determination portion (3) for determining on whether the image signal inputted is a high-gradation image or not, from that brightness histogram; and a level compensation portion (4) for lowering a gradation level of that image signal inputted. And, according to the present invention, lowering the gradation of the high-gradation image keeps the difference in brightness between the first and the second sub-frames, and thereby increasing an effect of improving the motion blur.

Claims

1. An image displaying apparatus, comprising:

a sub-frame producing portion, which is configured to produce a first sub-frame and a second sub-frame, which is lower in gradation thereof than said first sub-frame, from one (1) frame of image on an image signal inputted; and

a level compensation portion, which is configured to lower a gradation level of said image signal inputted, in case when the gradation of said image signal inputted is equal or greater than a predetermined value;

wherein said sub-frame producing portion produces the first and the second sub-frames with using the image signal, which is lowered in the gradation level thereof by means of said level compensation portion, when the gradation of said image signal inputted is equal or greater than the predetermined value.

2. The image displaying apparatus, as described in the claim 1, wherein said level compensation portion lowers the gradation level of said image signal inputted, by lowering a black level of said image signal inputted, when the gradation of said image signal inputted is equal or greater than the predetermined value.

3. The image displaying apparatus, as described in the claim 1, wherein said level compensation portion lowers the gradation level of said image signal inputted, by compressing an amplitude level of said image signal inputted, when the gradation of said image signal inputted is equal or greater than the predetermined value.

4. The image displaying apparatus, as described in the claim 1, wherein said image displaying apparatus is a liquid crystal displaying apparatus of hold-type of forming an image through modulation of a light from a light source, and further comprising:

a light source control portion, which is configure to increase an intensity of illumination of said light source, when the gradation of said image signal inputted is equal or greater than the predetermined value.

5. The image displaying apparatus, as described in the claim 1, wherein said level compensation portion lowers the gradation level of said image signal inputted, so that the gradation of said input comes to be equal or lower than a predetermined gradation.

6. An image displaying apparatus, comprising:

a liquid crystal displaying portion, which is configured to modulate a light from a light source;

a sub-frame producing portion, which is configured to produce a first sub-frame and a second sub-frame, which is lower in gradation thereof than said first sub-frame, from one (1) frame of image on an image signal inputted, to be supplied to said liquid crystal displaying portion;

a level compensation portion, which is configured to lower a gradation level of said image signal inputted, in case when said image signal inputted is a high-gradation image, gradation of which is equal or higher than a predetermined value; and

a light source control portion, which is configure to control an intensity of illumination from said light source;

wherein said sub-frame producing portion produces the first and the second sub-frames with using the image signal, which is lowered in the gradation level thereof by means of said level compensation portion, when said image signal inputted is the high-gradation image, and

said light source control portion controls so that the intensity of illumination from said light source is increased, when said image signal inputted is the high-gradation image.

7. The image displaying apparatus, as described in the claim 6, further comprising:

a histogram detection portion, which is configure to detect a histogram indicative of frequencies of appearances, for each of plural numbers of gradation areas, during a predetermined time-period, from said image signal inputted; and

an image determination portion, which is configured to determine on whether the image signal inputted is said high-gradation image or not, from the histogram detected by said histogram detection portion;

wherein said image determination portion determines that said image signal inputted is said high-gradation image, when the frequency of appearances in a predetermined gradation area is equal or greater than a predetermined threshold value on said histogram, and

said level compensation portion and said light source control portion are controlled depending upon a result of determination of said image determination portion.

8. The image displaying apparatus, as described in the claim 7, further comprising:

a detection range setup portion, which is configured to set up an image area where said histogram should be detected;

wherein said histogram is detected within a detection range, which is determined by said detection range setup portion.

9. The image displaying apparatus, as described in the claim 6, further comprising:

an APL detection portion, which is configured to detect an averaged brightness level during a predetermined time-period, from said image signal inputted;

an image determination portion, which is configured to determine on whether the image signal inputted is said high-gradation image or not, from the averaged brightness level detected by said APL detection portion;

wherein said image determination portion determines that said image signal inputted is said the high-gradation image, when said averaged brightness level is equal or greater than a predetermined value, and

said level compensation portion and said light source control portion are controlled depending upon a result of determination of said image determination portion.

10. The image displaying apparatus, as described in the claim 9, further comprising:

a detection range setup portion, which is configured to set up an image area where said averaged brightness level should be detected;

wherein said averaged brightness level is detected within a detection range, which is determined by said detection range setup portion.

11. An image displaying apparatus, comprising:

a sub-frame producing portion, which is configured to produce a plural number of sub-frames, differing in gradation from each other, from one (1) frame of image on an image signal inputted; and

a pull-down detection portion, which is configured to determine on whether said image signal inputted is a signal treated with 2-3 pull-down process or with 2-2 pull-down process;

wherein gradation levels are made equal to each other, between the sub-frames at exchange portions of the frames of said image signal inputted, among the plural number of the sub-frames, which are produced within said sub-frame producing portion, when determining that the image signal inputted is the signal treated with said pull-down process by said pull-down detection portion.

12. The image displaying apparatus, as described in the claim 11, further comprising:

a pull-down gradation level setup portion;

wherein grouping is made on the plural number of sub-frames, which are produced within said sub-frame producing portion, into four (4) pieces of sub-frames, and

said pull-down gradation level setup portion sets up a gradation level for each of said four (4) pieces of the grouped sub-frames, when said image signal inputted is determined to be the signal treated with the 2-2 pull-down process by said pull-down detection portion.

13. The image displaying apparatus, as described in the claim 12, wherein said pull-down gradation level setup portion determines the gradations for said four (4) pieces of the grouped sub-frames, so as to change in a step-like manner, and makes gradation levels at exchange portions of the frames being equal to each other.

14. The image displaying apparatus, as described in the claim 11, further comprising:

a pull-down gradation level setup portion;

wherein the plural number of sub-frames, which are produced within said sub-frame producing portion, are divided into a first group, by grouping every four (4) pieces of sub-frames, and a second group, by grouping every six (6) pieces of sub-frames, and

said pull-down gradation level setup portion sets up gradation levels, for each of the four (4) pieces of sub-frames included within said first group, and for each of the six (6) pieces of sub-frames included within said second group, when said image signal inputted is determined to be the signal treated with the 2-3 pull-down process.

15. The image displaying apparatus, as described in the claim 11, wherein said pull-down gradation level setup portion determines gradation levels for said four (4) pieces of the grouped sub-frames included within said first group and for the six (6) pieces of the sub-frames included within said second group, so as to change in a step-like manner, respectively, and makes gradation levels at exchange portions of the frames being equal to each other.