Flat-panel display device and display method

• US 6,128,045 A
• Filed: 03/27/1998
• Issued: 10/03/2000
• Est. Priority Date: 03/27/1997
• Status: Expired due to Term

• Current Assignee: Japan Display Central Incorporated (Japan Display Incorporated)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Anai, Kimio
• Primary Examiner(s): LEE, MICHAEL
• Application Number:
  US09/048,852
• Time in Patent Office: 921 Days
• Field of Search: 348/556, 348/792, 348/558, 348/555, 348/790, 348/441, 348/445, 348/913
• US Class Current: 348/556
• CPC Class Codes: H04N 7/0122 the input and the output signals having different aspect ratios

Abstract

A liquid crystal display device is composed of a liquid crystal panel including a plurality of pixels and a plurality of data signal lines, and a panel control unit CNT for controlling the liquid crystal panel so that a selected one of a high vision signal image and an NTSC signal image can be displayed. The control unit includes an auxiliary video signal generating circuit for generating an auxiliary video signal representing an auxiliary image to be displayed in first and second remainder areas provided on both sides of a display area for displaying an NTSC signal image on the screen of the liquid crystal panel. The control unit further includes a circuit for driving the data signal lines according to results obtained by sampling the auxiliary video signal in a horizontal blanking period of an NTSC video signal and the NTSC video signal in a period excluding the horizontal blanking period from one horizontal scanning period of the NTSC video signal.

Claims

1. A flat-panel display device comprising:

a display panel having a matrix array of pixels serving as a screen and a plurality of data signal lines formed to set potentials of the pixels of each row for displaying an image on the screen according to the potentials of the pixels; and

control means connected to receive a first video signal representing a first image and a second video signal representing a second image of an aspect ratio lower than that of the first image and for controlling the display panel such that the first image is displayed in a first display mode and the second image is displayed in a second display mode;

wherein the control means includes,

auxiliary video signal generating means for generating an auxiliary video signal representing an auxiliary image to be displayed on at least one side of the second image within the screen of the display panel in the second display mode, and

signal line driving means for driving the data signal lines according to sampling results obtained by sampling the second video signal and the auxiliary video signal during every horizontal scanning period for the second video signal, the auxiliary video signal being sampled in a horizontal blanking period included in the horizontal scanning period and not used for sampling the second video signal.

2. The flat-panel display device according to claim 1, wherein the signal line driving means includes sampling means for sampling the auxiliary video signal at a frequency higher than that of the second video signal.

3. The flat-panel display device according to claim 2, wherein a sampling frequency of the auxiliary video signal is equal to a sampling frequency of the first video signal when the first video signal represents the first image of an aspect ratio of 9:

16 and the second video signal represents the second image of an aspect ratio of 3;

4.

4. The flat-panel display device according to claim 1, wherein the signal line driving means includes sampling clock signal generating means for generating a sampling clock signal which is set at the first frequency to sample the auxiliary video signal and at the second frequency to sample the second video signal, and sampling means for sampling each of the auxiliary video signal and the second video signal in response to a corresponding sampling clock signal generated from the sampling clock generating means.

5. The flat-panel display device according to claim 4, wherein the sampling clock signal generating means includes reference sampling clock generating means for generating a reference sampling clock signal, first frequency-dividing means for frequency-dividing the reference sampling clock signal into a sampling clock signal of the first frequency, second frequency-dividing means for frequency-dividing the reference sampling clock signal to a sampling clock signal of the second frequency, and clock switch means for switching the sampling clock signal of the first frequency obtained by the first frequency-dividing circuit and the sampling clock signal of the second frequency obtained by the second frequency-dividing circuit.

6. The flat-panel display device according to claim 5, wherein the sampling clock generating means includes clock stop means for temporarily stopping supply of the sampling clock signal obtained by the clock switch means to the sampling means in accordance with a frequency transit period.

7. The flat-panel display device according to claim 1, wherein the signal line driving means includes video signal switch means for multiplexing the second video signal and the auxiliary video signal in a time-sharing manner in the second display mode.

8. The flat-panel display device according to claim 1, wherein the control means includes a positioning section for determining a position of the display area of the second image and sampling timing adjusting means for adjusting a sampling start timing of the signal line driving means in accordance with the position determined by the positioning section.

9. The flat-panel display device according to claim 8, wherein the positioning section includes a selecting section for selecting one of a leftmost position, a rightmost position and a center position as the position of the display area of the second image.

10. The flat-panel display device according to claim 8, wherein the control means includes:

a common voltage generating circuit for generating a common voltage level-inverted in at least every horizontal scanning period and serving as a reference voltage for the pixels;

a level inverting circuit for level-inverting the second video signal and the auxiliary video signal in synchronism with level inversion of the common voltage generated from the common voltage generating circuit; and

an inversion timing adjusting means for adjusting a level inversion timing of the common voltage generated from the common voltage generating circuit in accordance with the position determined by the positioning section.

11. A flat-panel display device comprising:

a display panel having a matrix array of pixels serving as a screen and a plurality of data signal lines formed to set potentials of the pixels of each row for displaying an image on the screen according to the potentials of the pixels; and

control means connected to receive a main video signal representing a main image of an aspect ratio of lower than that of the screen of said display panel and for controlling the display panel such that the main image is displayed;

wherein the control means includes,

auxiliary video signal generating means for generating an auxiliary video signal representing an auxiliary image to be displayed along with the main image within the screen of said display panel,

signal line driving means for driving the data signal lines according to sampling results obtained by sampling the main video signal and the auxiliary video signal in every horizontal scanning period for the main video signal, the auxiliary video signal being sampled in a horizontal blanking period included in the horizontal scanning period and not used for sampling the main video signal;

a positioning section for determining a display position of the main image, and

a sample timing adjusting means for adjusting sampling start timing of said signal line driving means in according with the display position determined by the positioning section.

12. The flat-panel display device according to claim 11, wherein the positioning section includes a selecting section for selecting one of a leftmost position, a rightmost position and a center position as the position of the display area of the main image.

13. The flat-panel display device according to claim 11, wherein the control means includes:

a common voltage generating circuit for generating a common voltage level-inverted in at least every horizontal scanning period and serving as a reference voltage for the pixels;

a level inverting circuit for level-inverting the main video signal and the auxiliary video signal in synchronism with level inversion of the common voltage generated from the common voltage generating circuit; and

an inversion timing adjusting means for adjusting a level inversion timing of the common voltage generated from the common voltage generating circuit in accordance with the display position determined by the positioning section.

14. A flat-panel display device comprising:

a display panel including rows of horizontal display pixels serving as an effective display screen of a predetermined aspect ratio and a plurality of data signal lines formed to set potentials of the pixels of each row; and

a data signal line driver section for supplying voltages obtained by sequentially sampling a video signal input thereto to the data signal lines, respectively; and

a controller section for controlling the video signal and sampling of the video signal;

wherein the controller section includes,

a display mode selecting section for selecting a display mode which specifies a position of a display area for the video signal within the display screen, and

a timing control section for setting a start timing and a clock for sampling based on the display mode selected by said display mode selecting section.

15. The flat-panel display device according to claim 14, wherein each horizontal scanning period for the video signal has an effective video period and a blanking period.

16. The flat-panel display device according to claim 15, wherein the video signal as another video information assigned to the blanking period.

17. The flat-panel display device according to claim 15, wherein the timing control section is constructed such that the sampling start timing is determined to cope with the effective video period and the sampling clock is determined so as to complete samplings for substantially all the data signal lines within the effective video period.

18. The flat-panel display device according to claim 15, wherein the timing control section is constructed such that the sampling start timing is determined in the blanking period between the effective video periods and the sampling clock is determined to be at a higher frequency in the blanking period than in the effective video period.

19. The flat-panel display device according to claim 18, wherein the frequency of the sampling clock is switched while the sampling is stopped.

20. A display method for displaying a first image corresponding to a first video signal in a first display mode and a second image corresponding to a second video image and having an aspect ratio lower than that of the first image in a second display mode on a display panel which has a matrix array of pixels serving as a screen and a plurality of data signal lines formed to set potentials of the pixels of each row, the method comprising the steps of:

generating an auxiliary video signal representing an auxiliary image to be displayed on at least one side of the second image within the screen of the display panel in the second display mode; and

driving the data signal lines according to sampling results obtained by sampling the second video signal and the auxiliary video signal in every horizontal scanning period for the second video signal, the auxiliary video signal being sampled in a horizontal blanking period included in the horizontal scanning period and not used for sampling the second video signal.

21. The display method according to claim 20, wherein the auxiliary video signal is sampled at a frequency higher than that of the second video signal.

22. The display method according to claim 21, wherein a sampling frequency of the auxiliary video signal is equal to a sampling frequency of the first video signal when the first video signal represents the first image of an aspect ratio of 9:

16 and the second video signal represents the second image of an aspect ratio of 3;

4.

23. The display method according to claim 20, wherein the auxiliary video signal is sampled in response to a sampling clock signal of a first frequency and the second video signal is sampled in response to a sampling clock signal of a second frequency.

24. The display method according to claim 23, wherein each of the sampling clock signals is produced by frequency-dividing a reference sampling clock signal.