# US 11,308,900 B2 · Display apparatus and method incorporating sub-pixel aware shifting and overlap compensation

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- Number: US 11,308,900 B2
- Document ID: US11308900B2
- Status: Granted
- Kind: B2
- Application number: 17/167,233
- Filed: 2021-02-04
- Published: 2021-08-12
- Granted: 2022-04-19
- Earliest claimed: 2020-02-06
- Assignees: Varjo Technologies Oy
- Applicants: Varjo Technologies Oy
- Inventors: Mikko Strandborg; Klaus Melakari; Ville Miettinen
- Web page: https://patentgrep.com/patent/US11308900B2

## CPC

- G09G 3/001: {using specific devices not provided for in groups G09G3/02 - G09G3/36, e.g. using an intermediate record carrier such as a film slide; Projection systems; Display of non-alphanumerical information, solely or in combination with alphanumerical information, e.g. digital display on projected diapositive as background (slide projectors per se G03B23/00 = 42 HP)}
- G09G 3/3607: {for displaying colours or for displaying grey scales with a specific pixel layout, e.g. using sub-pixels (display of colours in flat matrix panels other than liquid crystal displays G09G3/2003; grey scales specific for television H04N3/127)}
- G09G 3/003: {to produce spatial visual effects}
- G09G 3/2092: {Details of a display terminals using a flat panel, the details relating to the control arrangement of the display terminal and to the interfaces thereto (suitable for both CRT and flat panel G09G5/003; specific for a CRT G09G1/165)}
- G09G 3/3611: {Control of matrices with row and column drivers}
- G09G 3/3648: {using an active matrix (G09G3/367 - G09G3/3696 take precedence)}
- G09G 3/007: {Use of pixel shift techniques, e.g. by mechanical shift of the physical pixels or by optical shift of the perceived pixels}
- G09G 2300/0426: Layout of electrodes and connections
- G09G 2300/0452: Details of colour pixel setup, e.g. pixel composed of a red, a blue and two green components
- G09G 2300/0871: with level shifting
- G09G 2310/04: Partial updating of the display screen
- G09G 2320/0242: Compensation of deficiencies in the appearance of colours
- G09G 2320/028: by changing the viewing angle properties, e.g. widening the viewing angle, adapting the viewing angle to the view direction
- G09G 2340/0407: Resolution change, inclusive of the use of different resolutions for different screen areas
- G09G 2340/0435: Change or adaptation of the frame rate of the video stream
- G09G 2340/0457: Improvement of perceived resolution by subpixel rendering
- G09G 2340/0464: Positioning
- G09G 2354/00: Aspects of interface with display user
- G09G 2360/16: Calculation or use of calculated indices related to luminance levels in display data
- G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00)

## Abstract

In a display apparatus, a liquid-crystal structure, arranged in front of an image renderer, is controlled to shift light of a given sub-pixel to target positions according to a shifting sequence in a repeated manner, while output image frames are displayed. To generate a given output image frame, a given target position to which the light is to be shifted is determined based on the shifting sequence. An input colour value of the given sub-pixel provided in a given input image frame is then adjusted to generate an output colour value of the given sub-pixel for the given output image frame, based on an output colour value of at least one other sub-pixel whose light overlaps with the given target position during display of a previous output image frame, and a retention coefficient between a colour of the at least one other sub-pixel and a colour of the given sub-pixel.

## Claims

### Claim 1

A display apparatus comprising:
an image renderer having a plurality of pixels, a given pixel comprising at least three sub-pixels;
a liquid-crystal device comprising a liquid-crystal structure and a control circuit, wherein the liquid-crystal structure is arranged in front of an image-rendering surface of the image renderer, wherein the liquid-crystal structure is to be electrically controlled, via the control circuit, to shift light emanating from a given sub-pixel of the image renderer to a plurality of target positions on an image plane according to a shifting sequence in a repeated manner; and
at least one processor configured to:
process an input sequence of input image frames to generate an output sequence of output image frames; and
display the output image frames in the output sequence,
wherein, when processing a given input image frame to generate a given output image frame, the at least one processor is configured to:
determine a given target position on the image plane to which the light emanating from the given sub-pixel of the image renderer is to be shifted during display of the given output image frame, based on the shifting sequence;
adjust an input colour value of the given sub-pixel provided in the given input image frame to generate an output colour value of the given sub-pixel for the given output image frame, based on:
an output colour value of at least one other sub-pixel of the image renderer whose light overlaps with the given target position on the image plane during display of at least one previous output image frame, and
a retention coefficient between a colour of the at least one other sub-pixel and a colour of the given sub-pixel.

### Claim 2 (depends on 1)

The display apparatus claim 1, wherein the at least one previous output image frame comprises a first output image frame and a second output image frame, and the at least one other sub-pixel comprises a first sub-pixel and a second sub-pixel, wherein light emanating from the first sub-pixel is shifted to the given target position on the image plane during display of the first output image frame, and light emanating from the second sub-pixel is shifted to the given target position on the image plane during display of the second output image frame, the second output image frame being displayed subsequent to the first output image frame, wherein the given output image frame is to be displayed subsequent to the second output image frame,
wherein, when adjusting the input colour value of the given sub-pixel, the at least one processor is configured to apply a first weightage and a second weightage to a first retention coefficient between a colour of the first sub-pixel and the colour of the given sub-pixel and a second retention coefficient between a colour of the second sub-pixel and the colour of the given sub-pixel, respectively, the second weightage being greater than the first weightage.

### Claim 3 (depends on 2)

The display apparatus of claim 2, wherein the first weightage and the second weightage are determined based on time elapsed from the display of the first output image frame and the second output image frame, respectively, to the display of the given output image frame.

### Claim 4 (depends on 1)

The display apparatus of claim 1, wherein the at least one processor configured to determine the retention coefficient between the colour of the at least one other sub-pixel and the colour of the given sub-pixel, based on a frame rate of the image renderer.

### Claim 5 (depends on 1)

The display apparatus of claim 1, wherein the liquid-crystal structure is to be electrically controlled in a manner that one of the plurality of target positions overlaps with a physical position of the given sub-pixel on the image renderer, and at least two of the plurality of target positions overlap with physical positions of two neighbouring sub-pixels of the given sub-pixel on the image renderer.

### Claim 6 (depends on 1)

The display apparatus of claim 1, wherein the at least one processor is configured to select the input colour value of the given sub-pixel from amongst a plurality of input colour values provided for the given sub-pixel in the given input image frame, based on the given target position on the image plane, wherein a number of input colour values provided for the given sub-pixel in the given input image frame is equal to a number of target positions in the plurality of target positions.

### Claim 7

A method of displaying, via a display apparatus comprising an image renderer and a liquid-crystal device, the image renderer having a plurality of pixels, a given pixel comprising at least three sub-pixels, the liquid-crystal device comprising a liquid-crystal structure and a control circuit, wherein the liquid-crystal structure is arranged in front of an image-rendering surface of the image renderer, the method comprising:
electrically controlling the liquid-crystal structure, via the control circuit, to shift light emanating from a given sub-pixel of the image renderer to a plurality of target positions on an image plane according to a shifting sequence in a repeated manner;
processing an input sequence of input image frames to generate an output sequence of output image frames, wherein the step of processing a given input image frame to generate a given output image frame comprises:
determining a given target position on the image plane to which the light emanating from the given sub-pixel of the image renderer is to be shifted during display of the given output image frame, based on the shifting sequence; and
adjusting an input colour value of the given sub-pixel provided in the given input image frame to generate an output colour value of the given sub-pixel for the given output image frame, based on an output colour value of at least one other sub-pixel of the image renderer whose light overlaps with the given target position on the image plane during display of at least one previous output image frame, and a retention coefficient between a colour of the at least one other sub-pixel and a colour of the given sub-pixel; and
displaying the output image frames in the output sequence.

### Claim 8 (depends on 7)

The method of claim 7, wherein the at least one previous output image frame comprises a first output image frame and a second output image frame, and the at least one other sub-pixel comprises a first sub-pixel and a second sub-pixel, wherein light emanating from the first sub-pixel is shifted to the given target position on the image plane during display of the first output image frame, and light emanating from the second sub-pixel is shifted to the given target position on the image plane during display of the second output image frame, the second output image frame being displayed subsequent to the first output image frame, the given output image frame being displayed subsequent to the second output image frame,
wherein the step of adjusting the input colour value of the given sub-pixel comprises applying a first weightage and a second weightage to a first retention coefficient between a colour of the first sub-pixel and the colour of the given sub-pixel and a second retention coefficient between a colour of the second sub-pixel and the colour of the given sub-pixel, respectively, the second weightage being greater than the first weightage.

### Claim 9 (depends on 8)

The method of claim 8, further comprising determining the first weightage and the second weightage based on time elapsed from the display of the first output image frame and the second output image frame, respectively, to the display of the given output image frame.

### Claim 10 (depends on 9)

The method of claim 9, further comprising determining the retention coefficient between the colour of the at least one other sub-pixel and the colour of the given sub-pixel, based on a frame rate of the image renderer.

### Claim 11 (depends on 7)

The method of claim 7, wherein the liquid-crystal structure is electrically controlled in a manner that one of the plurality of target positions overlaps with a physical position of the given sub-pixel on the image renderer, and at least two of the plurality of target positions overlap with physical positions of two neighbouring sub-pixels of the given sub-pixel on the image renderer.

### Claim 12 (depends on 7)

The method of claim 7, further comprising selecting the input colour value of the given sub-pixel from amongst a plurality of input colour values provided for the given sub-pixel in the given input image frame, based on the given target position on the image plane, wherein a number of input colour values provided for the given sub-pixel in the given input image frame is equal to a number of target positions in the plurality of target positions.