INTERLACED LIQUID CRYSTAL DISPLAY PANEL AND BACKLIGHT USED IN A HEAD MOUNTED DISPLAY

• US 20180182307A1
• Filed: 12/27/2016
• Published: 06/28/2018
• Est. Priority Date: 12/27/2016
• Status: Active Grant

• Current Assignee: META Platforms Technologies LLC (Meta Platforms, Inc. (f/k/a Facebook, Inc.))
• Original Assignee: Oculus VR, LLC (Meta Platforms, Inc. (f/k/a Facebook, Inc.))
• Inventors: Tseng, Shie Ping Jeffrey, Richards, Evan M., Shi, Jianru, Shi, Yue
• Granted Patent: US 10,170,060 B2
• Time in Patent Office: Days
• CPC Class Codes: G02B 2027/0118 comprising devices for improving the contrast of the display / brillance control visibility
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02F 1/1336 Illuminating devices
• CPC Class Codes: G02F 1/133626 providing two modes of illumination, e.g. day-night
• CPC Class Codes: G02F 2201/30 grating
• CPC Class Codes: G06F 1/163 Wearable computers, e.g. on a belt
• CPC Class Codes: G06F 3/011 Arrangements for interaction with the human body, e.g. for user immersion in virtual reality blind teaching G09B21/00
• CPC Class Codes: G06F 3/012 Head tracking input arrangements
• CPC Class Codes: G06F 3/013 Eye tracking input arrangements G06F3/015 takes precedence
• CPC Class Codes: G09G 2310/0224 Details of interlacing
• CPC Class Codes: G09G 2310/0237 Switching ON and OFF the backlight within one frame
• CPC Class Codes: G09G 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 3/02 by tracing or scanning a light beam on a screen
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers

Abstract

A liquid crystal display (LCD) device is driven in interlaced scan to accommodate for liquid crystal (LC) setting times without sacrificing brightness. The LCD device includes an LCD panel including a first group of (e.g., even) pixel lines and a second group (e.g., odd) pixel lines, a backlight disposed behind the LCD panel to emit light toward the even and odd pixel lines, a shift grating disposed between the LCD and the backlight, the shift grating configured to block the light from the backlight from reaching either the first group of pixel lines or the second group of pixel lines, and a controller. The controller drives the LCD panel using an interlaced scan, coordinates the activation of the backlight (e.g., a strobed backlight), and changes the state of the shift grating to block the light from the backlight from reaching either the first group of pixel lines or the second group of pixel lines.

Claims

1. A display device, comprising:

an liquid crystal display (LCD) panel including at least a first group of pixel lines and a second group of pixel lines;

a backlight disposed behind the LCD panel to emit light toward the first and second groups of pixel lines;

a shift grating disposed between the LCD and the backlight, the shift grating configured to block the light from the backlight from reaching either the first group of pixel lines or the second group of pixel lines; and

a controller configured to;

set the first group of pixel lines with first group line data for a video frame;

control the backlight and the shift grating such that the light from the backlight illuminates the first group of pixel lines when the first group of pixel lines are set with the first group line data;

while the backlight is illuminating the first group of pixel lines and the first group line data is set on the first group of pixel lines, set the second group of pixel lines with second group line data for the video frame; and

control the backlight and the shift grating such that the light from the backlight illuminates the second group of pixel lines when the second group of pixel lines are set with the second group line data.

2. The display device of claim 1, wherein the first group of pixel lines are even pixel lines and the second group of pixel lines are odd pixel lines.

3. The display device of claim 1, wherein the backlight is a strobed backlight, and the controller configured to control the backlight includes the controller being configured to flash the strobe backlight on and off according to a periodic signal.

4. The display device of claim 1, wherein:

the controller configured to control the shift grating includes the controller being configured to provide a shift grating control signal that transitions the shift grating between a first state and a second state according to a periodic signal;

the shift grating blocks the light from the backlight from reaching the second group of pixel lines in the first state;

the shift grating blocks the light from the backlight from reaching the first group of pixel lines in the first state.

5. The display device of claim 1, wherein:

the first group of pixel lines and the second group of pixel lines include pixel line pairs, each pixel line pair including a first pixel line and an adjacent second pixel line; and

the display device further includes micro-optic elements disposed in front of the LCD panel, the micro-optics elements configured to, for each pixel line pair, spread light from the first pixel line and the adjacent second pixel line across a pixel space of the pixel line pair.

6. The display device of claim 5, wherein each micro-optics element includes a prism and a negative cylindrical lens.

7. The display of claim 1, wherein the controller is further configured to:

while the backlight is illuminating the second group of pixel lines and the second group line data is set on the second group of pixel lines, set the first group of pixel lines with second first group line data for a second video frame; and

control the back light and the shift grating that the light from the backlight illuminates the first group of pixel lines when the first group of pixel lines are set with the second first group line data.

8. The display device of claim 1, wherein:

the first group of pixel lines and the second group of pixel lines include pixel line pairs, each pixel line pair including a first pixel line and an adjacent second pixel line; and

the controller is further configured to generate the first group line data and the second group line data from the video frame such that the first group line data and second group line data are the same for each pixel line pair.

9. The display device of claim 1, wherein:

the liquid crystals (LCs) of the first group of pixel lines are set with the first group line data within a LC setting time

the LCs of the second group of pixel lines are set with the second group line data within a second LCD setting time; and

the controller is configured to control the backlight and the shift grating with periodic signals such that the light from the backlight illuminates the first group of pixel lines after the LC setting time and the light from the backlight illuminates the second group of pixel lines after the second LC setting time.

10. The display device of claim 1, wherein the controller is further configured:

set the first group of pixel lines with the first group line data using a first progressive scan of the first group of pixel lines; and

set the second group of pixel lines with the second group line data using a second progressive scan of the second group of pixel lines.

11. The display device of claim 1, wherein:

the controller sets each of the first group of pixel lines and the second group of pixel lines at a first refresh rate;

the controller controls the backlight to flash on and off at a second refresh rate;

the controller controls the shift grating to block the light from the backlight from reaching either the first group of pixel lines or the second group of pixel lines at the second refresh rate; and

the first refresh rate is half the second refresh rate.

12. A head-mounted display (HMD), comprising:

a display device, including;

an liquid crystal display (LCD) panel including at least a first group of pixel lines and a second group of pixel lines;

a backlight disposed behind the LCD panel to emit light toward the first and second groups of pixel lines;

a shift grating disposed between the LCD and the backlight, the shift grating configured to block the light from the backlight from reaching either the first group of pixel lines or the second group of pixel lines; and

a controller configured to;

set the first group of pixel lines with first group line data for a video frame;

control the backlight and the shift grating such that the light from the backlight illuminates the first group of pixel lines when the first group of pixel lines are set with the first group line data;

while the backlight is illuminating the first group of pixel lines and the first group line data is set on the first group of pixel lines, set the second group of pixel lines with second group line data for the video frame; and

control the backlight and the shift grating such that the light from the backlight illuminates the second group of pixel lines when the second group of pixel lines are set with the second group line data.

13. The HMD of claim 12, wherein the first group of pixel lines are even pixel lines and the second group of pixel lines are odd pixel lines.

14. The HMD of claim 12, wherein the backlight is a strobed backlight, and the controller configured to control the backlight includes the controller being configured to flash the strobe backlight on and off according to a periodic signal.

15. The HMD of claim 12, wherein:

the controller configured to control the shift grating includes the controller being configured to provide a shift grating control signal that transitions the shift grating between a first state and a second state according to a periodic signal;

the shift grating blocks the light from the backlight from reaching the second group of pixel lines in the first state;

the shift grating blocks the light from the backlight from reaching the first group of pixel lines in the first state.

16. The HMD of claim 12, wherein:

the first group of pixel lines and the second group of pixel lines include pixel line pairs, each pixel line pair including a first pixel line and an adjacent second pixel line; and

the display device further includes micro-optic elements disposed in front of the LCD panel, the micro-optics elements configured to, for each pixel line pair, spread light from the first pixel line and the adjacent second pixel line across a pixel space of the pixel line pair.

17. The HMD of claim 16, wherein each micro-optics element includes a prism and a negative cylindrical lens.

18. The HMD of claim 12, wherein the controller is further configured to:

while the backlight is illuminating the second group of pixel lines and the second group line data is set on the second group of pixel lines, set the first group of pixel lines with second first group line data for a second video frame; and

control the back light and the shift grating that the light from the backlight illuminates the first group of pixel lines when the first group of pixel lines are set with the second first group line data.

19. The HMD of claim 12, wherein:

the first group of pixel lines and the second group of pixel lines include pixel line pairs, each pixel line pair including a first pixel line and an adjacent second pixel line; and

the controller is further configured to generate the first group line data and the second group line data from the video frame such that the first group line data and second group line data are the same for each pixel line pair.

20. The HMD of claim 12, wherein:

the liquid crystals (LCs) of the first group of pixel lines are set with the first group line data within a LC setting time the LCs of the second group of pixel lines are set with the second group line data within a second LCD setting time; and

the controller is configured to control the backlight and the shift grating with periodic signals such that the light from the backlight illuminates the first group of pixel lines after the LC setting time and the light from the backlight illuminates the second group of pixel lines after the second LC setting time.

21. The HMD of claim 12, wherein the controller is configured to:

set the first group of pixel lines with the first group line data using a first progressive scan of the first group of pixel lines; and

set the second group of pixel lines with the second group line data using a second progressive scan of the second group of pixel lines.

22. The HMD of claim 12, wherein:

the controller sets each of the first group of pixel lines and the second group of pixel lines at a first refresh rate;

the controller controls the backlight to flash on and off at a second refresh rate;

the controller controls the shift grating to block the light from the backlight from reaching either the first group of pixel lines or the second group of pixel lines at the second refresh rate; and

the first refresh rate is half the second refresh rate.