Grating assembly, light source apparatus and driving method of the same

The present disclosure, belonging to the field of display technology, provides a grating assembly, a light source apparatus and a driving method thereof, which can solve a problem that an existing light source cannot provide light with a controllable direction. The grating assembly of the present disclosure comprises: a diffraction grating divided into a plurality of sub-pixels, each sub-pixel being divided into a plurality of regions, the diffraction grating being configured to change light transmitted through each region into parallel light and cause light transmitted through different regions of a same sub-pixel to have different directions; and a selector divided into a plurality of sub-pixels corresponding to sub-pixels of the diffraction grating, each sub-pixel being divided into a plurality of regions corresponding to the regions of the sub-pixel of the diffraction grating, the selector being configured to control whether each region thereof transmits light or not.

TECHNICAL FIELD

The present disclosure belongs to the field of display technology, and in particular relates to a grating assembly, a light source apparatus and a driving method of the same.

BACKGROUND

Many existing display devices have strict requirements for incident light, and only if a direction of incident light is determined, a direction of emergent light can be correctly controlled to perform display.

However, a light source used in an existing display device can only provide light with a fixed direction, and cannot flexibly adjust the direction of light at different times, and thus cannot satisfy requirements of many display devices.

SUMMARY

In view of the problem that an existing light source cannot provide light with a controllable direction, the present disclosure provides a grating assembly capable of providing light with a controllable direction, a light source apparatus and a driving method of the same.

Technical solutions to solve the technical problem of the present disclosure include a grating assembly comprising:

a diffraction grating, which is divided into a plurality of sub-pixels, each sub-pixel being divided into a plurality of regions, the diffraction grating being configured to change light transmitted through each region into parallel light, and to cause light transmitted through different regions of a same sub-pixel to have different directions; and

a selector, which is divided into a plurality of sub-pixels corresponding to the sub-pixels of the diffraction grating, each sub-pixel being divided into a plurality of regions corresponding to the regions of the sub-pixel of the diffraction grating, the selector being configured to control whether each region thereof transmits light or not.

Optionally, the grating assembly further comprises: a liquid crystal lens, wherein the selector and the diffraction grating are positioned on a same side of the liquid crystal lens; and the liquid crystal lens is divided into a plurality of sub-pixels corresponding to the sub-pixels of the diffraction grating, and is configured to control a direction of light transmitted through each sub-pixel thereof.

Optionally, each region of the selector is one liquid crystal switch.

Optionally, in one frame of image, the selector is configured to control the regions of each of the sub-pixels thereof to sequentially transmit light one by one.

Technical solutions to solve the technical problem of the present disclosure include a light source apparatus comprising:

a surface light source for emitting light; and

the above grating assembly, located in front of a light emitting surface of the surface light source.

Optionally, the grating assembly is the above grating assembly comprising a liquid crystal lens, wherein the diffraction grating and the selector are positioned between the liquid crystal lens and the surface light source.

Optionally, the diffraction grating is a light transmitting plate, and a plurality of diffraction chutes parallel to each other are provided in each region thereof, wherein the diffraction chutes in a same region have a same chute angle, and the diffraction chutes in different regions of a same sub-pixel have different chute angles and/or extending directions.

Optionally, the surface light source includes a light guide plate and a blue light emitting device provided outside the light guide plate, the light guide plate is capable of emitting yellow light upon excitation by blue light; the diffraction chutes in each region of the diffraction grating include blue light diffraction chutes and yellow light diffraction chutes having different widths and respectively for converting transmitted blue and yellow light into light having a same direction.

Optionally, the selector is provided between the diffraction grating and the surface light source.

Optionally, each region of the selector is one liquid crystal switch.

Optionally, in one frame of image, the selector is configured to control the regions of each of its sub-pixels to sequentially transmit light one by one.

Technical solutions to solve the technical problem of the present disclosure include a driving method for a light source apparatus, wherein the light source apparatus is the above light source apparatus, and the driving method comprises:

emitting light by the surface light source; and

controlling by the selector whether each region thereof transmits light or not.

Optionally, the light source apparatus is the above light source apparatus including a liquid crystal lens, and the driving method further includes:

allowing light emitted onto each sub-pixel thereof to transmit, and controlling a direction of the transmitted light, by the liquid crystal lens.

In the light source apparatus of the present disclosure, the diffraction grating converts irregular light, which is emitted from the surface light source into each sub-pixel, into multiple sets of parallel light that have different directions, and the selector independently controls whether these sets of light (light in each region) can be emitted out or not; therefore, a light exiting direction in each sub-pixel of the light source apparatus is controllable, and can satisfy requirements of various display devices.

The light source apparatus of the present disclosure is suitable for use as a light source of a display device.

DETAILED DESCRIPTION

In order to provide a better understanding of the technical solutions of the present disclosure to those skilled in the art, the present disclosure is described in further detail below in conjunction with the drawings and specific implementations.

First Embodiment

The present embodiment provides a grating assembly including:

a diffraction grating, which is divided into a plurality of sub-pixels, each sub-pixel being divided into a plurality of regions, the diffraction grating being configured to change light transmitted through each region into parallel light and to causelight transmitted through different regions of a same sub-pixel to have different directions; and

a selector, which is divided into a plurality of sub-pixels corresponding to the sub-pixels of the diffraction grating, each sub-pixel being divided into a plurality of regions corresponding to the regions of the corresponding sub-pixel of the diffraction grating, and the selector being configured to control whether each region thereof transmits light or not.

Optionally, the grating assembly further includes a liquid crystal lens, wherein the selector and the diffraction grating are positioned on a same side of the liquid crystal lens; and the liquid crystal lens is divided into a plurality of sub-pixels corresponding to the sub-pixels of the diffraction grating, and is configured to control a direction of light transmitted through each sub-pixel thereof.

Optionally, each region of the selector is one liquid crystal switch.

Optionally, in one frame of image, the selector is configured to control each of the regions of the sub-pixels thereof to sequentially transmit light one by one.

The grating assembly of the present embodiment can be used in a light source apparatus, such that a light exiting direction of the light source apparatus is controllable, details of which are described in the following embodiment of a light source apparatus.

Second Embodiment

As shown inFIGS. 1 to 5, the present embodiment provides a light source apparatus.

The light source apparatus can provide light having a controllable direction, more specifically, each of its sub-pixels9may controllably emit parallel light towards multiple different directions, and thus the light source apparatus is applicable to various display devices.

As shown inFIG. 1, the light source apparatus includes the grating assembly of the first embodiment (which includes a selector2and a diffraction grating3) and a surface light source1, and the grating assembly is provided in front of a light emitting surface of the surface light source1. That is, the light source apparatus includes:

a surface light source1for emitting light;

a diffraction grating3provided in front of a light emitting surface of the surface light source1, wherein the diffraction grating3is divided into a plurality of sub-pixels9, each sub-pixel9being divided into a plurality of regions91, and the diffraction grating3is configured to change light transmitted through each region91into parallel light and cause light transmitted through different regions91of a same sub-pixel9to have different directions; and

a selector2provided in front of the light emitting surface of the surface light source1, wherein the selector is divided into a plurality of sub-pixels9corresponding to the sub-pixels of the diffraction grating3, each sub-pixel9being divided into a plurality of regions91corresponding to the regions of the corresponding sub-pixel of the diffraction grating3, and the selector2is configured to control each region91thereof to transmit light or not to transmit light.

The diffraction grating3and the selector2constitute the above-described grating assembly, and thus they are both located in front of the light emitting surface of the surface light source1.

A structure of the diffraction grating3is shown inFIG. 3, a function thereof is to convert light emitted thereon in different directions (for simplicity, incident light shown in the figure is in a same direction) into parallel transmitted light. The diffraction grating3of the present embodiment is divided into a plurality of sub-pixels9, and each sub-pixel9corresponds to one smallest independently displayable “dot” in a display device, such as one red sub-pixel, green sub-pixel, blue sub-pixel or the like in the display device. As shown inFIG. 2, each sub-pixel9is further divided into a plurality of regions91(e.g., four regions91in the figure), the diffraction grating3has different structures in different regions91of one same sub-pixel9. Therefore, the diffraction grating3of the present embodiment can convert light transmitted from a same region91(the incident light may be in various directions) into parallel light, and can assure that light transmitted through different regions91of each sub-pixel9has different directions, in other words, the diffraction grating3is configured to convert light transmitted from different positions of each sub-pixel9into multiple sets of parallel light having different directions.

The selector2has sub-pixels9and regions91corresponding to the sub-pixels and the regions of the diffraction grating3(of course, the sub-pixels9also correspond to sub-pixels of the display device), and may control each region91thereof whether to transmit light or not, that is, control whether parallel light in each region91of the diffraction grating3can be finally emitted out from the light source apparatus (or the grating assembly).

It can be seen that in the light source apparatus of the present embodiment, the diffraction grating3converts irregular light, which is emitted from the surface light source1towards each sub-pixel9, into multiple sets of parallel light having different predetermined directions, and the selector2independently controls whether light in each region91can be emitted out or not; therefore, a light exiting direction of each sub-pixel9of the light source apparatus is controllable, and can satisfy requirements of various display devices.

Optionally, the grating assembly of the light source apparatus has a liquid crystal lens4, and the selector2and the diffraction grating3are both located between the surface light source1and the liquid crystal lens4.

That is to say, as shown inFIG. 1, optionally, the light source apparatus further includes a liquid crystal lens4provided in front of the diffraction grating3and the selector2(that is, at a side of the diffraction grating3and the selector2distal to the surface light source1). The liquid crystal lens4is divided into a plurality of sub-pixels9corresponding to the sub-pixels of the diffraction grating3, and is configured to control a direction of light transmitted through each sub-pixel9thereof. Specifically, the liquid crystal lens4includes a liquid crystal layer provided between two substrates, a driving electrode and a common electrode configured to drive the liquid crystal layer, and the like. By controlling voltages on the electrodes, liquid crystal molecules in the liquid crystal layer at corresponding positions can be twisted, thereby producing an effect similar to that of a “lens (or prism)” and changing a direction of transmitted light; of course, a specific degree, a direction or the like of the change may be further adjusted by changing voltages on the electrodes.

It can be seen that, as shown inFIG. 1, in the light source apparatus of the present embodiment, after light emitted by the surface light source1passes through the diffraction grating3, light corresponding to each sub-pixel9is then converted into multiple sets of parallel light having different directions; and the selector2may control the parallel light corresponding to each region91of each sub-pixel9of the diffraction grating3whether to enter the liquid crystal lens4or not and when to enter the liquid crystal lens4; after selected parallel light is emitted on a sub-pixel9of the liquid crystal lens4at a predetermined time, the liquid crystal lens4further changes its direction as required (light exiting direction may be different at different times), ensuring in the end that light with a desired direction can be emitted out from a desired position. Therefore, by providing the liquid crystal lens4, further adjustment of light passing through the diffraction grating3can be achieved, such that not only a light existing position of the light source apparatus is controllable (that is, whether to emit out light is determined for each direction), but also a light exiting direction is changeable (that is, a direction of light emitted out from each region91of each sub-pixel9can be changed as required).

Optionally, the diffraction grating3is a light transmitting plate, and each region91thereof is provided therein with a plurality of diffraction chutes31parallel to each other, wherein the diffraction chutes31in a same region91have a same chute angle r (the chute angle r is an included angle between a surface of the diffraction chute31and a lower surface of the diffraction grating3), and the diffraction chutes31in different regions91of a same sub-pixel9have different chute angles r and/or extending directions (FIGS. 3 and 4both show examples in which extending directions are the same, that is, the extending directions of the diffraction chutes31illustrated causes emergent light to be emitted “generally” towards the upper left (for example, as shown inFIGS. 3 and 4), thus it can be seen that difference in extending direction between diffraction chutes31of two regions91may cause a “general direction” of emergent light in one region to differ from a “general direction” of emergent light in the other region.

That is to say, as shown inFIG. 3, the diffraction grating3may be a light transmitting medium layer with a plurality of grooves (diffraction chutes31). Since the diffraction chutes31have a size in the order of nanometers, when a particular condition is satisfied, the diffraction chutes31may enhance zero-order diffracted light due to diffraction effect, and convert light emitted into the diffraction grating3from multiple different directions into light emitted out in a direction perpendicular to the surface (inclined surface) of the diffraction chutes31. In order that light emitted out from a same region91has a same direction, the diffraction chutes31in the same region91must have a same chute angle r and be parallel to each other; and in order that light emitted out from different regions91of one sub-pixel9have different directions, the diffraction chutes31in different regions91should have different chute angles r so as to change a “value of angle” of emergent light, or, the diffraction chutes31in different regions91should have different extending directions so as to change a “general direction” of emergent light.

Specifically, the condition to be satisfied to achieve the above conversion is: 2d×sin r=λ, where λ is a wavelength of the incident light, the chute angle r is an included angle between the surface of the diffraction chute31and the lower surface of the diffraction grating3. Since a light exiting direction of each region91is determined, the chute angle r is determined, and the wavelength λ of the incident light is also determined. Thus, a width d of the diffraction chute31in each region91(that is, a width of a vertical projection of the diffraction chute31on the lower surface of the diffraction grating3) should be set according to the wavelength λ and a desired chute angle r, which is not described in detail here.

Optionally, the surface light source1includes a light guide plate and a blue light emitting device (such as a blue LED) provided outside the light guide plate, and the light guide plate is capable of emitting yellow light upon excitation by the blue light; as shown inFIG. 4, the diffraction chutes31in each region91of the diffraction grating3include blue light diffraction chutes311and yellow light diffraction chutes312having different widths d and configured to convert transmitted blue light and yellow light into light having a same direction, respectively.

That is to say, the above surface light source1may employ an edge-type backlight source which is commonly used in liquid crystal display devices. The surface light source1mainly includes a light guide plate and a light emitting device (as well as an optical film layer such as a reflector, etc., of course). Light emitted by the light emitting device is emitted onto a side surface of the light guide plate, and is emitted out from a top surface of the light guide plate after undergoing a series of reflection, refraction and the like. However, in the surface light source1having the light guide plate, an LED emitting blue light (such as an organic light emitting diode) is commonly employed as an actual light emitting device, and the blue light emitted therefrom can also excite the light guide plate to general yellow light, such that emergent light becomes commonly desired white light by mixing the yellow light and the blue light. In this case, since wavelengths λ of the yellow and blue light are different, and it is to be ensured that light of the two colors in one region91have a same light exiting direction (that is, the chute angles r are the same), the widths d of the diffraction chutes31corresponding thereto must be different. Therefore, as shown inFIG. 4, it is required to provide two types of diffraction chutes31having different widths d but same chute angles r in a same region91of the diffraction grating3(since the wavelength of the blue light is shorter, the width d of the blue light diffraction chutes311is necessarily smaller), for diffracting yellow light and blue light, respectively, and the yellow and blue light emitted out is mixed again to become parallel white light.

Optionally, the selector2is provided between the diffraction grating3and the surface light source1.

As shown inFIG. 3, light has different transmission directions in different regions91after passing through the diffraction grating3, thus light in two regions91may possibly overlap with each other. To avoid this phenomenon, preferably, the selector2is provided at a side of the diffraction grating3close to the surface light source1, that is, light passes through the selector2first and is then emitted onto the diffraction grating3, so as to ensure that light is emitted into desired regions91of the diffraction grating3only, thereby preventing overlapping of emergent light.

Optionally, each region91of the selector2is one liquid crystal switch.

That is to say, the selector2may employ a form of a liquid crystal switch.

Specifically, the selector2may include two substrates, and a liquid crystal layer and a plurality of driving electrodes respectively corresponding to the regions91are provided on inner sides of the two substrates, and polarizers (such as linear polarizers with polarization directions perpendicular to each other) are provided on outer sides of the two substrates, thus whether each region91transmits light or not by can be determined by controlling a voltage of each driving electrode. There are various specific forms of the liquid crystal switch, which are not described in detail here.

Optionally, in one frame of image, the selector2is configured to control the regions91of each sub-pixel9thereof to sequentially transmit light one by one.

That is to say, as shown inFIG. 5, when providing light for one frame of display image, the above selector2controls the regions91of each of its sub-pixels9to sequentially be in a light transmitting state one by one (in the figure, a dotted area represents non-light transmitting state, and an empty area represents light transmitting state), that is, in each of the sub-pixels9, only one region91transmits light at any arbitrary time, and in one frame, each of the regions91of each of the sub-pixels9transmits light once. Accordingly, for the diffraction grating3, in each of its sub-pixels9, light emitted out from only one region91can be emitted into the liquid crystal lens4at any arbitrary time. Thus for the liquid crystal lens4, parallel light having only one direction is emitted into each of its sub-pixels9at any arbitrary time, such that a light exiting direction can be controlled most precisely.

The light source apparatus of the present embodiment may control light emitted out from each sub-pixel9to be sequentially emitted towards multiple different directions in one frame of image. Therefore, a light exiting direction in each of the sub-pixels9in a display device using the light source apparatus can also be controllable. As long as a proportion of time when light emitted out from a certain sub-pixel9into human eyes in one frame of image is controlled, an energy density of light received by human eyes can be controlled, such that a human feels a change in brightness of the sub-pixel9.

Third Embodiment

The present embodiment provides a driving method for the above light source apparatus, including:

emitting light by the surface light source1, and controlling by the selector2whether each region91thereof transmits light or not.

Optionally, for the above light source apparatus having the liquid crystal lens4, the driving method further includes:

allowing light emitted onto each sub-pixel9thereof to transmit and controlling a direction of the transmitted light, by the liquid crystal lens4,1.

That is, when driving the light source apparatus of the embodiment to emit light, the surface light source1may be caused to emit light continuously, and the time at which and the angle in which parallel light is emitted onto each of the sub-pixels9of the liquid crystal lens4are determined by the selector2and the diffraction grating3, and the liquid crystal lens4then redirects the light towards a desired direction, so as to satisfy requirements of the display device.

It can be understood that the foregoing implementations are merely exemplary implementations used for describing the principle of the present disclosure, but the present disclosure is not limited thereto. Those of ordinary skill in the art may make various variations and modifications without departing from the spirit and essence of the present disclosure, and these variations and modifications shall fall into the protection scope of the present disclosure.