Display device with backlight unit having switchable multi-coloured lightsources

1 . A system comprising:

tracking means;

a display device comprising:

a backlight unit comprising a plurality of light sources that are controllable, to switch between lights of different colours;

an active panel comprising:

a liquid crystal (LC) layer comprising a plurality of LC cells;

a linear polarizer arranged on an optical path of the LC layer; and

a drive circuit employed to individually control the plurality of LC cells of the LC layer; and

at least one processor configured to:

obtain at least one predefined sequence in which sub-images of a given image are to be displayed via the display device, wherein each of the sub-images corresponds to a respective one of at least two different colours; and

display the sub-images of the given image by employing temporal multiplexing, wherein when displaying the sub-images of the given image, the at least one processor is configured to:

generate different sets of drive signals corresponding to respective ones of the sub-images of the given image, based on the at least one predefined sequence in which the sub-images are to be displayed, wherein for a given sub-image, a corresponding set of drive signals is generated to individually control the plurality of LC cells of the LC layer, based on intensity values of pixels in the given sub-image;

send the different sets of drive signals to the drive circuit according to the at least one predefined sequence in which the sub-images are to be displayed; and

control individually, via the drive circuit, the plurality of LC cells of the LC layer using the different sets of drive signals according to the at least one predefined sequence, whilst controlling the backlight unit to switch between lights of the at least two different colours according to the at least one predefined sequence in which the sub-images are to be displayed via the display device;

the system further comprising:

a multiscopic optical element arranged on an optical path of the display device; and

at least one processor configured to:

determine a relative location of a first eye and of a second eye of at least one user with respect to an image plane of the display device, by utilising the tracking means, wherein the given image is a light field image that is generated or retrieved based on the relative location of the first eye and of the second eye of the at least one user with respect to the image plane; and

control the multiscopic optical element, based on the relative location of the first eye and of the second eye of the at least one user with respect to the image plane, to direct light corresponding to a first set of pixels and a second set of pixels of the light field image to produce a first part and a second part of a synthetic light field, respectively, for the first eye and the second eye of the at least one user,

wherein the system further comprises an optical combiner arranged on an optical path of the display device and on an optical path of a real-world light field of a real-world environment, wherein the optical combiner is employed to reflect the first part and the second part of the synthetic light field towards the first eye and the second eye of the at least one user, whilst optically combining the real-world light field with the first part and the second part of the synthetic light field.

2 . The display device of claim 1 , wherein the at least one processor is configured to display sub-images of another given image by employing temporal multiplexing, wherein the sub-images of the another given image are displayed according to at least one another predefined sequence, the at least one another predefined sequence being different from the at least one predefined sequence employed for the given image.

3 . The display device of claim 1 , wherein the at least one predefined sequence in which the sub-images of the given image are to be displayed is obtained based on colours of at least one virtual object being presented by the given image.

4 . The display device of claim 3 , wherein the backlight unit is colour-adjustable on a per-region basis, the at least one predefined sequence comprising at least two different predefined sequences, wherein when obtaining the at least one predefined sequence, the at least one processor is configured to obtain the at least two different predefined sequences to be employed for respective ones of at least two different regions of the given image, based on colours of different parts of the at least one virtual object being presented respectively by the at least two different regions of the given image.

5 . The display device of claim 1 , wherein the backlight unit is colour-adjustable on a per-region basis, the at least one predefined sequence comprising a first predefined sequence and a second predefined sequence, wherein the at least one processor is configured to:

obtain information indicative of a gaze direction of a user; and

determine a first region and a second region of the given image, based on the gaze direction of the user, wherein the second region surrounds the first region,

wherein when obtaining the at least one predefined sequence, the at least one processor is configured to obtain the first predefined sequence and the second predefined sequence to be employed for the first region and the second region of the given image, respectively.

6 . The display device of claim 1 , wherein the at least one processor is configured to:

detect when at least a region of a next image is to present an emergency notification to a user; and

when it is detected that at least the region of the next image is to present the emergency notification to the user,

control the backlight unit to produce light of a same colour for sub-images of the next image;

generate a same set of drive signals for the sub-images of the next image, to individually control the plurality of LC cells of the LC layer according to intensity values of pixels in one of the sub-images that corresponds to the same colour;

send the same set of drive signals to the drive circuit for the sub-images of the next image; and

control individually, via the drive circuit, the plurality of LC cells of the LC layer using the same set of drive signals, whilst the backlight unit is controlled to produce the light of the same colour, thereby displaying the next image using the same colour.

7 . The display device of claim 1 , wherein the backlight unit is colour-adjustable on a per-region basis, wherein the at least one processor is configured to:

detect when a region of a next image is to present an emergency notification to a user; and

when it is detected that the region of the next image is to present the emergency notification to the user,

determine a region of the backlight unit that corresponds to said region of the next image;

control said region of the backlight unit to produce light of a same colour, whilst controlling a remaining region of the backlight unit to switch between lights of at least two different colours according to a corresponding predefined sequence in which the sub-images of the next image are to be displayed via the display device;

generate a same set of drive signals for respective regions of the sub-images of the next image that correspond to said region of the next image, whilst generating different sets of drive signals for respective ones of remaining regions of the sub-images of the next image, based on the corresponding predefined sequence in which the sub-images are to be displayed; and

send, to the drive circuit, the same set of drive signals for said respective regions of the sub-images of the next image, and the different sets of drive signals for the respective ones of said remaining regions of the sub-images of the next image according to the corresponding predefined sequence in which the sub-images are to be displayed.

8 . The display device of claim 1 , wherein the plurality of light sources of the backlight unit are implemented as at least one white light source and at least one colour wheel arranged on an optical path of the at least one white light source, wherein the at least one colour wheel comprises colour filters of primary colours.

9 . The display device of claim 1 , wherein the plurality of light sources of the backlight unit are implemented as a plurality of laser light sources of primary colours, the backlight unit further comprising a light guide employed to guide light emitted by the plurality of light sources towards the active panel, wherein the plurality of laser light sources are individually controllable.

10 . The display device of claim 1 , wherein the plurality of light sources of the backlight unit are implemented as an array of light-emitting elements of primary colours, wherein the light-emitting elements of said array are individually controllable.

11 . The display device of claim 10 , wherein a given sub-image of the given image corresponds to one of the primary colours, wherein when displaying the given sub-image, the at least one processor is configured to:

activate light-emitting elements of the one of the primary colours in at least a region of said array, to produce light of the one of the primary colours at full brightness; and

simultaneously, activate a first predefined percent of light-emitting elements of at least one other of the primary colours in at least said region of said array, to produce light of the at least one other of the primary colours at a second predefined percent of full brightness.

12 . The display device of claim 10 , wherein another given sub-image of the given image corresponds to a non-primary colour that corresponds to additive mixing of a first primary colour and a second primary colour, wherein when displaying the another given sub-image, the at least one processor is configured to:

activate light-emitting elements of the first primary colour in at least a region of said array, to produce light of the first primary colour; and

simultaneously, activate light-emitting elements of the second primary colour in at least said region of said array, to produce light of the second primary colour.

13 . A method comprising:

obtaining at least one predefined sequence in which sub-images of a given image are to be displayed via a display device, wherein the display device comprises a backlight unit comprising a plurality of light sources that are controllable to switch between lights of different colours, and an active panel comprising a liquid crystal (LC) layer comprising a plurality of LC cells, a linear polarizer arranged on an optical path of the LC layer, and a drive circuit employed to individually control the plurality of LC cells of the LC layer; and

displaying the sub-images of the given image by employing temporal multiplexing, wherein each of the sub-images corresponds to a respective one of at least two different colours, wherein the step of displaying the sub-images of the given image comprises:

generating different sets of drive signals corresponding to respective ones of the sub-images of the given image, based on the at least one predefined sequence in which the sub-images are to be displayed, wherein for a given sub-image, a corresponding set of drive signals is generated to individually control the plurality of LC cells of the LC layer, based on intensity values of pixels in the given sub-image;

sending the different sets of drive signals to the drive circuit according to the at least one predefined sequence in which the sub-images are to be displayed; and

controlling individually, via the drive circuit, the plurality of LC cells of the LC layer using the different sets of drive signals according to the at least one predefined sequence, whilst controlling the backlight unit to switch between lights of the at least two different colours according to the at least one predefined sequence in which the sub-images are to be displayed via the display device;

the method further comprising:

determining a relative location of a first eye and of a second eye of at least one user with respect to an image plane of the display device, by utilising a tracking means, wherein the given image is a light field image that is generated or retrieved based on the relative location of the first eye and of the second eye of the at least one user with respect to the image plane; and

controlling a multiscopic optical element, arranged on an optical path of the display device, based on the relative location of the first eye and of the second eye of the at least one user with respect to the image plane, to direct light corresponding to a first set of pixels and a second set of pixels of the light field image to produce a first part and a second part of a synthetic light field, respectively, for the first eye and the second eye of the at least one user,

employing an optical combiner arranged on an optical path of the display device and on an optical path of a real-world light field of a real-world environment, to reflect the first part and the second part of the synthetic light field towards the first eye and the second eye of the at least one user, whilst optically combining the real-world light field with the first part and the second part of the synthetic light field.

14 . The method of claim 13 , further comprising displaying sub-images of another given image by employing temporal multiplexing, wherein the sub-images of the another given image are displayed according to at least one another predefined sequence, the at least one another predefined sequence being different from the at least one predefined sequence employed for the given image.

15 . The method of claim 13 , wherein the at least one predefined sequence in which the sub-images of the given image are to be displayed is obtained based on colours of at least one virtual object being presented by the given image,

wherein optionally, the backlight unit is colour-adjustable on a per-region basis, and the at least one predefined sequence comprises at least two different predefined sequences, and wherein the step of obtaining the at least one predefined sequence comprises obtaining the at least two different predefined sequences to be employed for respective ones of at least two different regions of the given image, based on colours of different parts of the at least one virtual object being presented respectively by the at least two different regions of the given image.

16 . The method of claim 13 , wherein the backlight unit is colour-adjustable on a per-region basis, the at least one predefined sequence comprising a first predefined sequence and a second predefined sequence, wherein the method further comprises:

obtaining information indicative of a gaze direction of a user; and

determining a first region and a second region of the given image, based on the gaze direction of the user, wherein the second region surrounds the first region, wherein the step of obtaining the at least one predefined sequence comprises obtaining the first predefined sequence and the second predefined sequence to be employed for the first region and the second region of the given image, respectively.

17 . The method of claim 13 , further comprising:

detecting when at least a region of a next image is to present an emergency notification to a user; and

when it is detected that at least the region of the next image is to present the emergency notification to the user,

controlling the backlight unit to produce light of a same colour for sub-images of the next image;

generating a same set of drive signals for the sub-images of the next image, to individually control the plurality of LC cells of the LC layer according to intensity values of pixels in one of the sub-images that corresponds to the same colour;

sending the same set of drive signals to the drive circuit for the sub-images of the next image; and

controlling individually, via the drive circuit, the plurality of LC cells of the LC layer using the same set of drive signals, whilst the backlight unit is controlled to produce the light of the same colour, thereby displaying the next image using the same colour.

18 . The method of claim 13 , wherein the backlight unit is colour-adjustable on a per-region basis, wherein the method further comprises:

detecting when a region of a next image is to present an emergency notification to a user; and

when it is detected that the region of the next image is to present the emergency notification to the user,

determining a region of the backlight unit that corresponds to said region of the next image;

controlling said region of the backlight unit to produce light of a same colour, whilst controlling a remaining region of the backlight unit to switch between lights of at least two different colours according to a corresponding predefined sequence in which the sub-images of the next image are to be displayed via the display device;

generating a same set of drive signals for respective regions of the sub-images of the next image that correspond to said region of the next image, whilst generating different sets of drive signals for respective ones of remaining regions of the sub-images of the next image, based on the corresponding predefined sequence in which the sub-images are to be displayed; and

sending, to the drive circuit, the same set of drive signals for said respective regions of the sub-images of the next image, and the different sets of drive signals for the respective ones of said remaining regions of the sub-images of the next image according to the corresponding predefined sequence in which the sub-images are to be displayed.

19 . The method of claim 13 , wherein the plurality of light sources of the backlight unit are implemented as an array of light-emitting elements of primary colours, wherein the light-emitting elements of said array are individually controllable,

wherein optionally, a given sub-image of the given image corresponds to one of the primary colours, and wherein the step of displaying the given sub-image comprises:

activating light-emitting elements of the one of the primary colours in at least a region of said array, to produce light of the one of the primary colours at full brightness; and

simultaneously, activating a first predefined percent of light-emitting elements of at least one other of the primary colours in at least said region of said array, to produce light of the at least one other of the primary colours at a second predefined percent of full brightness.

20 . The method of claim 19 , wherein another given sub-image of the given image corresponds to a non-primary colour that corresponds to additive mixing of a first primary colour and a second primary colour, and wherein the step of displaying the another given sub-image comprises:

activating light-emitting elements of the first primary colour in at least a region of said array, to produce light of the first primary colour; and

simultaneously, activating light-emitting elements of the second primary colour in at least said region of said array, to produce light of the second primary colour.