IMAGE DISPLAY APPARATUS AND METHOD FOR CONTROLLING SAME

• US 20180040279A1
• Filed: 02/12/2016
• Published: 02/08/2018
• Est. Priority Date: 02/23/2015
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Kimura, Takushi, Kanai, Izumi, Furumoto, Yoshihisa, Ikeda, Takeshi
• Granted Patent: US 10,636,368 B2
• Time in Patent Office: Days
• CPC Class Codes: G02F 1/133602 Direct backlight
• CPC Class Codes: G02F 1/133611 including means for improving the brightness uniformity
• CPC Class Codes: G02F 2203/64 Normally black display, i.e. the off state being black
• CPC Class Codes: G09G 2320/0238 Improving the black level
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/342 using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines
• 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

An image display apparatus includes: a display unit; a plurality of light emitting units; and a light-emission controller configured to individually control light-emission brightness of each of the light emitting units, wherein in a case where brightness of light applied to a region of the display unit on which a black region of an input image is displayed is less than or equal to predetermined brightness, transmittance of the display unit is controlled such that transmittance of the region of the display unit corresponding to the black region becomes higher than that in a case in which the brightness is higher than the predetermined brightness.

Claims

1. An image display apparatus comprising:

a display unit configured to display an image by controlling transmittance of light based on an input image;

a plurality of light emitting units configured to apply light to the display unit; and

a light-emission controller configured to individually control light-emission brightness of each of the light emitting units based on brightness of each part of the input image corresponding to each of the light emitting units, wherein

in a case where brightness of light applied to a region of the display unit on which a black region of the input image is displayed is less than or equal to predetermined brightness, transmittance of the display unit is controlled such that transmittance of the region of the display unit corresponding to the black region becomes higher than that in a case in which the brightness is higher than the predetermined brightness.

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

in a case where the brightness of the light applied to the region of the display unit corresponding to the black region is higher than the predetermined brightness, the transmittance of the region of the display unit corresponding to the black region is controlled at transmittance lower than predetermined transmittance.

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

the transmittance of the display unit is controlled based on a gradation value of the input image, and

the transmittance of the region of the display unit corresponding to the black region is controlled based on a predetermined gradation value in a case where the brightness of the light applied to the region of the display unit corresponding to the black region is higher than the predetermined brightness.

4. The image display apparatus according to claim 1, further comprising:

a first corrector configured to increase a gradation value smaller than a first gradation value of the input image to generate a first correction image; and

a second corrector configured to correct a gradation value of a pixel of the first correction image according to brightness of light applied to a region of the display unit corresponding to the pixel and reduce the corrected gradation value smaller than a second gradation value to generate a second correction image, wherein

the transmittance of the display unit is controlled based on the second correction image.

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

the second corrector converts the corrected gradation value smaller than the second gradation value into a gradation value representing a black color to generate the second correction image.

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

the light-emission controller individually controls the light-emission brightness of each of the light emitting units based on brightness of each part of the first correction image corresponding to each of the light emitting units, and

the second corrector corrects a gradation value of the first correction image according to the light-emission brightness of each of the light emitting units.

7. The image display apparatus according to claim 4, further comprising:

an estimation unit configured to estimate distribution of the brightness of the light applied to the display unit using the light-emission brightness of each of the light emitting units, wherein

the second corrector corrects the gradation value of the first correction image into a greater gradation value as the brightness estimated by the estimation unit is lower.

8. The image display apparatus according to claim 1, further comprising:

a brightness setting unit configured to set a maximum value of display brightness capable of being displayed by the image display apparatus, wherein

a ratio of a minimum value of light-emission brightness capable of being controlled by the light-emission controller to a maximum value of the light-emission brightness capable of being controlled by the light-emission controller is smaller as the maximum value of the display brightness is higher.

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

a ratio of a minimum value of light-emission brightness capable of being controlled by the light-emission controller to a maximum value of the light-emission brightness capable of being controlled by the light-emission controller is smaller as the first gradation value is greater.

10. An image display apparatus comprising:

a plurality of light emitting units configured to apply light to a display unit;

a light-emission controller configured to individually control light-emission brightness of each of the light emitting units based on brightness of each part of an image corresponding to each of the light emitting units;

a first corrector configured to increase a gradation value smaller than a first gradation value of an input image to generate a first correction image;

a second corrector configured to correct a gradation value of a pixel of the first correction image according to brightness of light applied to the display unit corresponding to the pixel and reduce the corrected gradation value smaller than a second gradation value to generate a second correction image; and

the display unit configured to display an image by transmitting light applied from the plurality of light emitting units based on the second correction image.

11. A method for controlling an image display apparatus having a display unit configured to display an image by transmitting light, and a plurality of light emitting units configured to apply light to the display unit, the method comprising:

a light-emission control step of individually controlling light-emission brightness of each of the light emitting units based on brightness of each part of an input image corresponding to each of the light emitting units; and

a transmittance control step of controlling transmittance of the display unit based on the input image, wherein

in a case where brightness of light applied to a region of the display unit on which a black region of the input image is displayed is less than or equal to predetermined brightness, transmittance of the display unit is controlled in the transmittance control step such that transmittance of the region of the display unit corresponding to the black region becomes higher than that in a case in which the brightness is higher than the predetermined brightness.

12. The method according to claim 11, wherein

in a case where the brightness of the light applied to the region of the display unit corresponding to the black region is higher than the predetermined brightness, in the transmittance control step, the transmittance of the region of the display unit corresponding to the black region is controlled at transmittance lower than predetermined transmittance.

13. The method according to claim 11, wherein

in the transmittance control step,

the transmittance of the display unit is controlled based on a gradation value of the input image, and

the transmittance of the region of the display unit corresponding to the black region is controlled based on a predetermined gradation value in a case where the brightness of the light applied to the region of the display unit corresponding to the black region is higher than the predetermined brightness.

14. The method according to claim 11, further comprising:

a first correction step of increasing a gradation value smaller than a first gradation value of the input image to generate a first correction image; and

a second correction step of correcting a gradation value of a pixel of the first correction image according to brightness of light applied to a region of the display unit corresponding to the pixel and reducing the corrected gradation value smaller than a second gradation value to generate a second correction image, wherein

in the transmittance control step, the transmittance of the display unit is controlled based on the second correction image.

15. The method according to claim 14, wherein

in the second correction step, the corrected gradation value smaller than the second gradation value is converted into a gradation value representing a black color to generate the second correction image.

16. The method according to claim 15, wherein

in the light-emission control step, the light-emission brightness of each of the light emitting units is individually controlled based on brightness of each part of the first correction image corresponding to each of the light emitting units, and

in the second correction step, a gradation value of the first correction image is corrected according to the light-emission brightness of each of the light emitting units.

17. The method according to claim 14, further comprising:

an estimation step of estimating distribution of the brightness of the light applied to the display unit using the light-emission brightness of each of the light emitting units, wherein

in the second correction step, the gradation value of the first correction image is corrected into a greater gradation value as the brightness estimated in the estimation step is lower.

18. The method according to claim 11, further comprising:

a brightness setting step of setting a maximum value of display brightness capable of being displayed by the image display apparatus, wherein

a ratio of a minimum value of light-emission brightness capable of being controlled in the light-emission control step to a maximum value of the light-emission brightness capable of being controlled in the light-emission control step is smaller as the maximum value of the display brightness is higher.

19. The method according to claim 11, wherein

a ratio of a minimum value of light-emission brightness capable of being controlled in the light-emission control step to a maximum value of the light-emission brightness capable of being controlled in the light-emission control step is smaller as the first gradation value is greater.

20. A method for controlling an image display apparatus having a display unit configured to display an image by transmitting light, and a plurality of light emitting units configured to apply light to the display unit, the method comprising:

a light-emission control step of individually controlling light-emission brightness of each of the light emitting units based on brightness of each part of an image corresponding to each of the light emitting units;

a first correction step of increasing a gradation value smaller than a first gradation value of an input image to generate a first correction image;

a second correction step of correcting a gradation value of a pixel of the first correction image according to brightness of light applied to the display unit corresponding to the pixel and reducing the corrected gradation value smaller than a second gradation value to generate a second correction image; and

a transmittance control step of controlling transmittance of the display unit, based on the second correction image.