Pseudo Multi-Domain Design for Improved Viewing Angle and Color Shift

• US 20100207862A1
• Filed: 02/13/2009
• Published: 08/19/2010
• Est. Priority Date: 02/13/2009
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Xu, Ming, Gu, Mingxia, Chen, Cheng, Zhong, John Z., Chang, Shih Chang, Gettemy, Shawn Robert
• Granted Patent: US 8,531,408 B2
• Time in Patent Office: Days
• US Class Current: 345/90
• CPC Class Codes: G02F 1/133512 Light shielding layers, e.g. black matrix G02F1/136209 takes precedence
• CPC Class Codes: G02F 1/133707 Structures for producing distorted electric fields, e.g. bumps, protrusions, recesses, slits in pixel electrodes
• CPC Class Codes: G02F 1/13373 Disclination line; Reverse tilt
• CPC Class Codes: G02F 1/134336 Matrix
• CPC Class Codes: G02F 1/134363 for applying an electric field parallel to the substrate, i.e. in-plane switching [IPS]
• CPC Class Codes: G02F 1/134372 for fringe field switching [FFS] where the common electrode is not patterned

Abstract

Aspects of the present disclosure relate to single-domain electrode configurations that may be implemented in the unit pixels of a LCD device, such as a fringe field switching (FFS) LCD, to provide a “pseudo-multi-domain” effect, wherein the benefits of both conventional single-domain and multi-domain pixel configuration devices are retained. In accordance with aspects of the present technique, single-domain unit pixels are angled or tilted in differing directions with respect to a vertical axis of the LCD panel (e.g., y-axis) to provide an alternating and/or periodic arrangement of different-angled pixel electrodes along each scanning line, data line, or a combination of both scanning and data lines. In this manner, the transmittance rates of conventional single-domain LCD panels may be retained while providing for improved viewing angle and color shift properties typical of conventional multi-domain LCD panels.

Claims

1. A liquid crystal display (LCD) panel, comprising:

a pixel array having a plurality of unit pixels, each being in a single-domain configuration, comprising;

a first set of unit pixels, wherein each of the first set of unit pixels comprises electrodes generally parallel to one another; and

a second set of unit pixels, wherein each of the second set of unit pixels comprises electrodes generally parallel to one another, but not generally parallel to the electrodes of the first set of unit pixels;

wherein the plurality of unit pixels are arranged in a plurality of groups, wherein each group comprises three directly adjacent unit pixels coupled to a common scanning line, wherein the three unit pixels comprise a red unit pixel, a blue unit pixel, and a green unit pixel, and wherein the three unit pixels within each group comprise either two unit pixels from the first set and one unit pixel from the second set, or one unit pixel from the first set and two unit pixels from the second set.

2. The LCD panel of claim 1, wherein the two unit pixels from the first set or the two unit pixels from the second set are directly adjacent along the common scanning line.

3. The LCD panel of claim 1, wherein the electrodes of the first set of unit pixels are tilted by a first angle in a first angular direction with respect to a vertical axis of the LCD panel, and wherein the electrodes of the second set of unit pixels are tilted by a second angle in a second angular direction with respect to the vertical axis, and wherein the first and second angular directions are opposite from each other.

4. The LCD panel of claim 3, wherein the magnitudes of the first and second angles are not substantially equal.

5. The LCD panel of claim 3, wherein the magnitudes of the first and second angles are substantially equal.

6. The LCD panel of claim 3, wherein the magnitude of the first angle is greater than 0°

with respect to the vertical axis, and wherein the magnitude of the second angle is less than 90°

with respect to the vertical axis.

7. The LCD panel of claim 3, wherein the magnitude of the first angle is greater than 0°

with respect to the vertical axis, and wherein the magnitude of the second angle is less than or equal to 15°

with respect to the vertical axis.

8. The LCD panel of claim 3, wherein the magnitude of the first angle is greater than or equal to 75°

with respect to the vertical axis, and wherein the magnitude of the second angle is less than 90°

with respect to the vertical axis.

9. The LCD panel of claim 1, wherein the magnitude of the first and second angles have a range from 15°

to 75°

.

10. The LCD panel of claim 1, wherein the plurality of unit pixels in the pixel array are arranged in rows and columns, and wherein the first and second set of unit pixels are arranged such that the unit pixels from the first and second sets alternate along a row, alternate along a column, or alternate along rows and columns of the pixel array.

11. The LCD panel of claim 1, wherein the electrodes of the first and second set of unit pixels comprise one or more of indium tin oxide or indium zinc oxide.

12. The LCD panel of claim 1, wherein the LCD panel comprises a fringe field switching (FFS) LCD panel.

13. The LCD panel of claim 1, wherein the LCD panel comprises a light-opaque matrix defining a light-transmissive aperture over each of the plurality of unit pixels, and wherein each of the apertures includes a color filter, and wherein the red, blue, and green unit pixels of each group of unit pixels are determined by a corresponding color filter associated with a respective aperture.

14. A liquid crystal display (LCD) panel, comprising:

a pixel array having a plurality of unit pixels arranged in a rows and columns defined by scanning lines and data lines, respectively, the pixel array comprising;

a first set of unit pixels, wherein each of the first set of unit pixels comprises electrodes generally parallel to one another but not generally parallel to a vertical axis of the LCD panel; and

a second set of unit pixels, wherein each of the second set of unit pixels comprises electrodes generally parallel to one another, but not generally parallel to the electrodes of the first set of unit pixels or the vertical axis;

wherein the scanning lines comprise a first set of scanning lines and a second set of scanning lines, and wherein each of the first set of unit pixels is coupled to one of the first set of scanning lines and respective data lines, and wherein each of the unit pixels from the second set of unit pixels is coupled to one of a second set of scanning lines and respective data lines, wherein the first and second sets of scanning lines are arranged in an alternating manner along the vertical axis of the LCD panel, and wherein each of the data lines are oriented such that the portions of each data line disposed between adjacent scanning lines are generally parallel to the electrodes of directly adjacent unit pixels.

15. The LCD panel of claim 14, wherein the plurality of unit pixels are arranged in groups of three directly adjacent unit pixels coupled to a common one of the scanning lines, wherein the three unit pixels comprise a red unit pixel, a blue unit pixel, and a green unit pixel.

16. The LCD panel of claim 14, wherein the electrodes of the first set of unit pixels are tilted by a first angle in a first angular direction with respect to the vertical axis, and wherein the electrodes of the second set of unit pixels are tilted by a second angle in a second angular direction with respect to the vertical axis, and wherein the first and second angular directions are opposite from each other.

17. The LCD panel of claim 14, wherein each of the data lines forms a generally zigzag shape generally along the vertical axis of the LCD panel.

18. The LCD panel of claim 14, comprising driving circuitry configured to transmit image data to the scanning lines and to the data lines.

19. The LCD panel of claim 14, comprising a light-opaque matrix defining a light-transmissive aperture over each of the first and second sets of unit pixels, wherein edges of each aperture in the direction of the vertical axis are generally parallel to the electrodes of its respective unit pixel.

20. The LCD panel of claim 19, wherein the light-opaque matrix masks disclinations between directly adjacent unit pixels coupled to either directly adjacent scanning lines or to directly adjacent data lines.

21. The LCD panel of claim 14, wherein the electrodes of each of the plurality of unit pixels have a single-domain configuration.

22. A method for displaying image data in a liquid crystal display (LCD) panel having an array of unit pixels arranged in rows and columns defined by scanning lines and data lines, respectively, the method comprising:

supplying a data signal representative of at least a portion of the image data to each of the data lines; and

supplying a scanning signal to each of the scanning lines, wherein the scanning lines comprises a first set of scanning lines and a second set of scanning lines, wherein the first set of scanning lines is coupled to a first set of unit pixels having pixel electrodes oriented at a first angle with respect to a vertical axis of the LCD panel in a first angular direction, wherein the second set of scanning lines is coupled to a second set of unit pixels having pixel electrodes oriented at a second angle with respect to the vertical axis in a second angular direction, and wherein the first and second sets of scanning lines are arranged in an alternating manner along the vertical axis;

wherein the first and second angular directions are opposite from each other, and wherein each data line has a generally zigzag generally shape along the vertical axis and is oriented such that the portions of each data line between adjacent scanning lines are generally parallel to the electrodes of directly adjacent unit pixels.

23. The method of claim 22, wherein the data signals are supplied to the data lines in a sequential manner.

24. The method of claim 22, wherein, when activated, each of the unit pixels from the first set generates an electrical field in a first direction and each of the unit pixels from the second set generates an electrical field in a second direction.

25. The method of claim 24, comprising masking disclinations resulting from interference between the first and second electric fields using a light-opaque matrix defining a light-transmissive aperture over each of the unit pixels of within the LCD panel.

26. A method for masking disclinations in a liquid crystal display (LCD) panel, comprising:

providing a light-opaque material disposed over a pixel array comprising a plurality of unit pixels arranged in rows and columns defined by scanning lines and data lines, respectively, the plurality of unit pixels comprising;

a first set of unit pixels having pixel electrodes oriented in a first angular direction at a first angle with respect to a vertical axis of the LCD panel and configured to generate an electrical field in a first direction; and

a second set of unit pixels having pixel electrodes oriented in a second angular direction opposite the first angular direction and at a second angle with respect to the vertical axis and configured to generate an electrical field in a second direction;

wherein an electrical field in the first direction and an electrical field in the second direction respectively generated by two directly adjacent unit pixels, including one unit pixel from the first set and one unit pixel from the second set, interfere with each other and cause one or more disclinations to form between the directly adjacent unit pixels, the one or more disclinations at least partially preventing light provided from a light source from being transmitted through the first unit pixel or the second unit pixel;

wherein the light-opaque material forms a matrix defining a light-transmissive aperture bordered by the light-opaque material over each of the plurality of unit pixels, wherein the light-opaque borders corresponding to the directly adjacent unit pixels mask the one or more disclinations.

27. The method of claim 26, wherein the light source comprises one of a backlight assembly or a light-reflective surface

28. The method of claim 26, wherein unit pixels coupled to a common one of the scanning lines within the pixel array are arranged in groups of three unit pixels, each group comprising a red unit pixel, a blue unit pixel, and a green unit pixel.

29. The method of claim 28, wherein each group of unit pixels comprises either two unit pixels from the first set and one unit pixel from the second set, or one unit pixel from the first set and two unit pixels from the second set.

30. The method of claim 26, wherein the unit pixels coupled to a respective data line are all from the first set of unit pixels or all from the second set of unit pixels.

31. The method of claim 26, wherein the unit pixels coupled to a respective data line alternate between a unit pixel from the first set and a unit pixel from the second set.

32. A liquid crystal display (LCD) panel, comprising:

a pixel array having a plurality of unit pixels comprising;

a first set of unit pixels having substantially straight pixel electrodes oriented in a first angular direction at a first angle that is less than 90 degrees with respect to a vertical axis of the LCD panel; and

a second set of unit pixels having substantially straight pixel electrodes oriented in a second angular direction opposite the first angular direction and at a second angle that is less than 90 degrees with respect to the vertical axis;

wherein the magnitudes of the first and second angles are not equal; and

a liquid crystal layer comprising a plurality of liquid crystal molecules disposed between a lower alignment layer and an upper alignment layer, wherein the lower and upper alignment layers are configured to align the liquid crystal layer in a direction that is offset from the vertical axis of the LCD panel by a third angle having a magnitude that is between the magnitudes of the first and the second angles.

33. The LCD panel of claim 32, wherein the plurality of unit pixels in the pixel array are arranged in rows and columns, and wherein the first and second set of unit pixels are arranged such that the unit pixels from the first and second sets alternate along a row, alternate along a column, or alternate along rows and columns of the pixel array.

34. The LCD panel of claim 32, wherein the liquid crystal molecules of the liquid crystal layer are disposed in one of a fluid material or a polymer network.

35. The LCD panel of claim 32, wherein the upper and lower alignment layers and the liquid crystal layer are disposed over the pixel electrodes, and wherein the LCD panel comprises a light source disposed under the pixel array and configured to transmit light through liquid crystal layer.

36. The LCD panel of claim 35, wherein, when oriented in a vertical or horizontal position and viewed through a polarized medium, the LCD panel having the liquid crystal layer aligned at the third angle is perceived as having a higher transmittance rate relative to an LCD panel having a liquid crystal layer aligned in a direction parallel to either the horizontal or vertical axis of the LCD panel.