Image Display Apparatus, Image Display Monitor, and Television Receiver

• US 20090122207A1
• Filed: 03/15/2006
• Published: 05/14/2009
• Est. Priority Date: 03/18/2005
• Status: Abandoned Application

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Shigeta, Mitsuhiro, Shiraishi, Tai, Kumakura, Takeshi, Inoue, Akihiko
• Application Number:
  US11/883,941
• Publication Number:
  US 20090122207A1
• Time in Patent Office: Days
• US Class Current: 348/739
• CPC Class Codes: G09G 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 2320/0247 Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
• CPC Class Codes: G09G 2320/0261 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 2320/0606 Manual adjustment
• CPC Class Codes: G09G 2320/0613 The adjustment depending on the type of the information to be displayed
• CPC Class Codes: G09G 2320/0673 for control of gamma adjustment, e.g. selecting another gamma curve
• 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 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/2011 by amplitude modulation
• CPC Class Codes: G09G 3/2025 the sub-frames having all the same time duration
• CPC Class Codes: G09G 3/2081 with combination of amplitude modulation and time modulation space and time error diffusion G09G3/2066
• CPC Class Codes: G09G 3/3208 organic, e.g. using organic light-emitting diodes [OLED]
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers

Abstract

In the first display mode, a first tone converting circuit and a second tone converting circuit of a control LSI divide one frame period of an input image signal into a plurality of sub-frame periods to perform output to a display panel, thus realizing image display performed by time-division driving (pseudo-impulse driving). In the second display mode, the control LSI directly outputs an input image signal to the display panel, thus realizing image display performed by hold driving. In at least one embodiment, switching between the first display mode and the second display mode is performed by changing output of an output data selector according to a mode switching signal. This realizes an image display apparatus which effectively obtains the effect of suppressing blurring of a moving image and alleviates the problem of flickers caused by pseudo-impulse driving.

Claims

1. An image display apparatus having a first display mode and a second display mode,

the first display mode being a mode in which one frame period is divided into a plurality of sub-frame periods, and luminance of the one frame period based on an input image signal is distributed to the sub-frames so that the luminance of the one frame period is reproduced by the sub-frames for image display,

the second display mode being a mode in which image display during one frame period is performed at a single luminance level so that luminance of the one frame period based on an input image signal is reproduced,

wherein said image display apparatus switches between the first display mode and the second display mode to perform image display.

2. The image display apparatus according to claim 1, wherein

in the second display mode the one frame period is regarded as a single frame period so that a predetermined luminance is reproduced during the one frame period.

3. The image display apparatus according to claim 1, wherein

in the second display mode the one frame period is divided into a plurality of sub-frame periods, and luminance levels inputted into the respective sub-frames are equal to each other.

4. The image display apparatus according to claim 1, wherein

said image display apparatus has switching means that switches between the first display mode and the second display mode.

5. The image display apparatus according to claim 1, wherein

switching between the first display mode and the second display mode is performed by an external input operation.

6. The image display apparatus according to claim 1, wherein

switching between the first display mode and the second display mode is performed according to nature of an input image.

7. The image display apparatus according to claim 6, wherein

said image display apparatus determines whether the input image is a moving image or a still image to switch between the first display mode and the second display mode.

8. The image display apparatus according to claim 7, wherein

when the input image is determined as a moving image, the first display mode is selected, and

when the input image is determined as a still image, the second display mode is selected.

9. The image display apparatus according to claim 6, wherein

switching between the first display mode and the second display mode is performed according to average luminance of the input image.

10. The image display apparatus according to claim 9, wherein

when the average luminance of the input image is determined as being low, the first display mode is selected, and

when the average luminance of the input image is determined as being high, the second display mode is selected.

11. The image display apparatus according to claim 6, wherein

said image display apparatus switches between the first display mode and the second display mode according to frame frequency of the input image.

12. The image display apparatus according to claim 11, wherein

when the frame frequency of the input image is determined as being high, the first display mode is selected, and

when the frame frequency of the input image is determined as being low, the second display mode is selected.

13. The image display apparatus according to claim 12, wherein

a frame frequency threshold value, which is a criterion for switching between the first display mode and the second display mode, is set to be in a range from 50 Hz to 60 Hz.

14. The image display apparatus according to claim 1, wherein

switching between the first display mode and the second display mode is performed according to a result of image source determination in which a supply source of the input image is determined.

15. The image display apparatus according to claim 1, wherein

the nature of the input image is determined for each of pixels on the basis of the input image signal, and switching between the first display mode and the second display mode is performed according to a result of the determination.

16. The image display apparatus according to claim 1, wherein

the nature of the input image is determined for each of sub-areas on the basis of the input image signal, switching between the first display mode and the second display mode is performed according to a result of the determination.

35. An image display monitor comprising:

an image display apparatus according to claim 1; and

a signal input section for transmitting an external input image signal to the image display apparatus.

36. A television receiver comprising an image display apparatus according to claim 1.

17. An image display apparatus comprising:

first signal generating means that divides one frame period into a plurality of sub-frame periods, and generates a display image signal such that luminance of the one frame period based on an input image signal is distributed to the sub-frames so that the luminance of the one frame period is reproduced by a sum total of time integral values of luminance of the respective sub-frames; and

second signal generating means that generates a display image signal such that the one frame period is regarded as a single frame period so that a predetermined luminance is reproduced during the one frame period,

wherein

switching between output of the first signal generating means and output of the second signal generating means is performed so that the display image signal is outputted to a display section.

18. The image display apparatus according to claim 17, further comprising:

switching means that switches between output of the first signal generating means and output of the second signal generating means to output the display image signal to the display section.

19. The image display apparatus according to claim 17, wherein

switching between output of the first signal generating means and output of the second signal generating means is able to be performed by an external input operation.

20. The image display apparatus according to claim 17, further comprising:

determining means that determines nature of an input image on the basis of an input image signal, wherein

switching between output of the first signal generating means and output of the second signal generating means is performed according to a result of the determination performed by the determining means.

21. The image display apparatus according to claim 20, wherein

the determining means is moving/still image determining means that determines whether the input image is a moving image or a still image.

22. The image display apparatus according to claim 21, wherein

when the input image is determined as a moving image, the output of the first signal generating means is supplied as the display image signal to the display section, and

when the input image is determined as a still image, the output of the second signal generating means is supplied as the display image signal to the display section.

23. The image display apparatus according to claim 20, wherein

the determining means is luminance measuring means that measures average luminance of the input image.

24. The image display apparatus according to claim 23, wherein

when the average luminance of the input image is determined as being low, the output of the first signal generating means is supplied as the display image signal to the display section, and

when the average luminance of the input image is determined as being high, the output of the second signal generating means is supplied as the display image signal to the display section.

25. The image display apparatus according to claim 20, wherein

the determining means is frame frequency measuring means that measures frame frequency of the input image.

26. The image display apparatus according to claim 25, wherein

when the frame frequency of the input image is determined as being high, the output of the first signal generating means is supplied as the display image signal to the display section, and

when the frame frequency of the input image is determined as being low, the output of the second signal generating means is supplied as the display image signal to the display section.

27. The image display apparatus according to claim 26, wherein

the switching means has a frame frequency threshold value set to be in a range from 50 Hz to 60 Hz, the frame frequency threshold value being a criterion for switching between output of the first signal generating means and output of the second signal generating means.

28. The image display apparatus according to claim 17, further comprising:

image source determining means that determines a supply source of the input image,

wherein

the switching means switches between the output of the first signal generating means and the output of the second signal generating means according to a result of the determination performed by the image source determining means.

29. The image display apparatus according to claim 20, wherein

the determining means determines the nature of the input image for each of pixels on the basis of the input image signal, and

switching between the output of the first signal generating means and the output of the second signal generating means is performed for each of the pixels according to a result of the determination performed by the determining means.

30. The image display apparatus according to claim 29, wherein

the determining means is moving/still image determining means that determines for each of pixels whether the pixel corresponds to a moving image or a still image on the basis of the input image, wherein

for a pixel which is determined as corresponding to a moving image on the basis of the input image, the output of the first signal generating means is outputted as the display image signal to the display section, and for a pixel which is determined as corresponding to a still image on the basis of the input image, the output of the second signal generating means is outputted as the display image signal to the display section.

31. The image display apparatus according to claim 29, wherein

the determining means is luminance measuring means that measures luminance of each of pixels in the input image, wherein

for a pixel of which luminance is determined as being low in the input image, the output of the first signal generating means is supplied as the display image signal to the display section, and for a pixel of which luminance is determined as being high in the input image, the output of the second signal generating means is supplied as the display image signal to the display section.

32. The image display apparatus according to claim 17, wherein

the determining means determines the nature of the input image for each of sub-areas on the basis of the input image signal, and

switching between the output of the first signal generating means and the output of the second signal generating means is performed for each of the sub-areas according to a result of the determination performed by the determining means.

33. The image display apparatus according to claim 32, wherein

the determining means is moving/still image determining means that determines for each of sub-areas whether a sub-area corresponds to a moving image or a still image on the basis of the input image, and

for a sub-area which is determined as corresponding to a moving image on the basis of the input image, the output of the first signal generating means is supplied as the display image signal to the display section, and for a sub-area which is determined as corresponding to a still image on the basis of the input image, the output of the second signal generating means is supplied as the display image signal to the display section.

34. The image display apparatus according to claim 32, wherein

the determining means is luminance measuring means that measures luminance of each of sub-areas in the input image, and

for a sub-area of which average luminance is determined as being low in the input image, the output of the first signal generating means is supplied as the display image signal to the display section, and for a sub-area of which average luminance is determined as being high in the input image, the output of the second signal generating means is supplied as the display image signal to the display section.