HOLD-TYPE IMAGE DISPLAY APPARATUS AND DISPLAY METHOD USING THE HOLD-TYPE IMAGE DISPLAY APPARATUS

• US 20110025726A1
• Filed: 07/16/2010
• Published: 02/03/2011
• Est. Priority Date: 07/28/2009
• Status: Abandoned Application

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Tatsumi, Eisaku
• Application Number:
  US12/837,603
• Publication Number:
  US 20110025726A1
• Time in Patent Office: Days
• US Class Current: 345/690
• 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 2320/0276 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 2340/0435 Change or adaptation of the frame rate of the video stream
• 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 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336

Abstract

An image processing circuit generates an output video signal from an input video signal and outputs the output video signal to a display panel with a higher frame frequency than the frame frequency of the input video signal. The output video signal includes a main-frame image and a sub-frame image. The image processing circuit has a luminance control unit. When the frame frequency of the output video signal is Io, and the display luminance of the sub-frame is B (0<B<0.5), the luminance control unit determines the ratio of the display luminance between the main-frame image and the sub-frame image so that the frequency In calculated by B=(2/3)×(1−(Io/2In)²) is equal to or more than 65 Hz and equal to or less than 80 Hz.

Claims

1. A hold-type image display apparatus comprising:

a display panel having a plurality of display devices; and

an image processing circuit which generates an output video signal, including a main-frame image corresponding to an original image included in an input video signal and a sub-frame image generated by interpolation of the original image, from the input video signal, and, outputs the output video signal to the display panel with a higher frame frequency than the frame frequency of the input video signal,

wherein

the image processing circuit has a luminance control unit which controls a display luminance of each frame image of the output video signal according to the frame frequency of the output video signal, and

when the frame frequency of the output video signal is Io and the display luminance of the sub-frame image is B (the sum of the display luminance of the main-frame image and the display luminance of the sub-frame image is 1, and, 0<

B<

0.5), the luminance control unit determines, with regard to at least the display luminance corresponding to the maximum gradation, the ratio of the display luminance between the main-frame image and the sub-frame image so that the frequency In calculated by B=(2/3)×

(1−

(Io/2In)²) is equal to or more than 65 Hz and equal to or less than 80 Hz.

2. The hold-type image display apparatus according to claim 1,

wherein the ratio of the display luminance between the main-frame image and the sub-frame image is constant regardless of the input video signal.

3. A hold-type image display apparatus comprising:

a display panel having a plurality of display devices; and

an image processing circuit which generates an output video signal, including a main-frame image corresponding to an original image included in an input video signal and a sub-frame image generated by interpolation of the original image, from the input video signal, and, outputs the output video signal to the display panel with a higher frame frequency than the frame frequency of the input video signal,

wherein

the image processing circuit has a luminance control unit which controls a display luminance of each frame image of the output video signal,

with regard to at least the display luminance corresponding to the maximum gradation, the luminance control unit renders the display luminance of the sub-frame image smaller than the display luminance of the main-frame image, and

the ratio of the display luminance between the main-frame image and the sub-frame image is constant regardless of the input video signal.

4. The hold-type image display apparatus according to claim 3,

wherein the luminance control unit renders the ratio of the display luminance of sub-frame image to the display luminance of the main-frame image in a low gradation region smaller than the ratio in a high gradation region.

5. The hold-type image display apparatus according to claim 3,

wherein the image processing circuit comprises a luminance ratio changing unit which changes the ratio of the display luminance of the sub-frame image to the display luminance of the main-frame image, according to an instruction value input by a viewer.

6. The hold-type image display apparatus according to claim 3,

wherein the luminance control unit is a gradation conversion circuit that controls the display luminance of each frame image by converting the respective gradations of the main-frame image and the sub-frame image with the use of different gradation conversion characteristics.

7. The hold-type image display apparatus according to claim 3,

wherein the luminance control unit is a voltage control circuit that controls the display luminance of each frame image by making a value of a drive voltage, applied to the plurality of display devices, different between the main-frame image and the sub-frame image.

8. The hold-type image display apparatus according to claim 3,

wherein the display panel has a backlight, and the luminance control unit is a backlight control circuit that controls the display luminance of each frame image by making the luminance of the backlight different between the main-frame image and the sub-frame image.

9. A display method using a hold-type image display apparatus, which includes a display panel having a plurality of display devices, comprising the steps of:

generating, from an input video signal, an output video signal that includes a main-frame image, corresponding to an original image included in the input video signal, and a sub-frame image generated by interpolation of the original image;

controlling a display luminance of each frame image of the output video signal according to a frame frequency of the output video signal; and

outputting the output video signal to the display panel with a higher frame frequency than the frame frequency of the input video signal,

wherein

when the frame frequency of the output video signal is Io and the display luminance of the sub-frame image is B (the sum of the display luminance of the main-frame image and the display luminance of the sub-frame image is 1, and, 0<

B<

0.5), with regard to at least the display luminance corresponding to the maximum gradation, the ratio of the display luminance between the main-frame image and the sub-frame image is determined so that the frequency In calculated by B=(2/3)×

(1−

(Io/2In)²) is equal to or more than 65 Hz and equal to or less than 80 Hz.