Patent Description:
In a display apparatus including an optical waveguide, light from a light source of the display apparatus may be coupled into or out of the optical waveguide through a grating to complete display of the display apparatus.

<CIT> provides a display device including a backlight unit including a field sequential light source operated using a sequential partition method and an optical shutter using an electrowetting phenomenon disposed on a light emitting surface of the backlight unit and switching light outputted from the backlight unit.

<CIT> provides a biomimetic optical stack that operates on the basis of electrowetting. The stack is comprised of several layers of solid and liquid materials sandwiched together to form a single hermetic panel. The first layer in the stack is a dielectric (<NUM>). The second layer in the stack is an electrode (<NUM>). The third layer in the stack is a discriminator (<NUM>). The fourth layer in the stack is an electrode (<NUM>) that is spaced apart from discriminator (<NUM>). The space between discriminator (<NUM>) and electrode (<NUM>) is filled with an anterior liquid (<NUM>) and a posterior liquid (<NUM>) that are immiscible. Liquid (<NUM>) is composed of an insulating fluid that exhibits a stronger affinity for the surface of discriminator (<NUM>) than does liquid (<NUM>). Liquid (<NUM>) is composed of a conducting fluid that exhibits a stronger affinity for the surface of electrode (<NUM>) than does liquid (<NUM>). The final layer in the stack is a dielectric (<NUM>).

<CIT> provides a liquid crystal display device including an upper substrate; a lower substrate facing the upper substrate; a liquid crystal layer formed between the upper and the lower substrates; common electrodes and pixel electrodes formed parallel to each other in pixel regions of the lower substrate; and polymer walls formed between the upper and the lower substrates. A manufacturing method includes forming gate and data lines on a lower substrate, the gate and data lines intersecting each other to define a plurality of pixel regions; forming thin film transistors at respective intersections of the gate and data lines; forming common electrodes and pixel electrodes in parallel with each other in the pixel regions; joining an upper substrate with the lower substrate so that a liquid crystal layer is disposed between the upper and the lower substrates; and forming a plurality of polymer walls between the upper and the lower substrates.

<CIT> provides a head-mounted display (HMD) including a frame configured to be fixated to a head, a light-transmissive display unit fixated to the frame and outputting a VR image in a VR mode and an AR image in an AR mode, a light transmission control layer having changed transmittance, a lens unit having a refractive index changed in the VR mode and the AR mode, and a controller control the light transmission control layer to increase transmittance in the AR mode and decrease transmittance in the VR mode.

<CIT> discloses an electrowetting device (an iris diaphragm) in which the electrowetting fluid comprises melanin.

In one aspect, an optical switch is provided. The optical switch is defined by appended claim <NUM>.

In another aspect, a control method of an optical switch is provided. The control method is defined by appended claim <NUM>.

In yet another aspect, a display apparatus is provided. The display apparatus is defined by appended claim <NUM>.

In order to explain technical solutions in some embodiments of the present disclosure more clearly, the accompanying drawings used in some embodiments of the present disclosure will be introduced briefly. Obviously, the accompanying drawings to be described below are merely some embodiments of the present disclosure, and a person of ordinary skill in the art may obtain other drawings according to these drawings.

Technical solutions in some embodiments of the present disclosure will be described clearly and completely with reference to accompanying drawings in some embodiments of the present disclosure. Obviously, the described embodiments are merely some but not all embodiments of the present disclosure.

In the field of optics, Fraunhofer diffraction (also referred to as far-field diffraction) is a type of wave diffraction that typically occurs when a field wave passes through a circular hole or a slit. This causes a problem that in a display apparatus including an optical waveguide, if an area of an orthographic projection of a grating on a display surface of the display apparatus is small, when light is coupled into or out of the optical waveguide through the grating, optical crosstalk is easy to occur due to generation of the Fraunhofer diffraction. That is, a display effect of the display apparatus is adversely affected. For example, brightness of an image displayed by the display apparatus is caused to be uneven and the image is caused to be blurred, or display distortion is caused. In addition, in a display apparatus using a pinhole imaging technique, the Fraunhofer diffraction is also easy to occur when light exits through the pinhole, thereby reducing a display effect of the display apparatus.

On this basis, some embodiments of the present disclosure provide an optical switch. As shown in <FIG>, the optical switch includes a plurality of micro-grooves <NUM>, a micro-fluid <NUM> disposed in each micro-groove <NUM> of the plurality of micro-grooves <NUM>, and a driving electrode <NUM> disposed corresponding to the micro-fluid <NUM> in each micro-groove <NUM>. The driving electrode <NUM> is configured to provide a voltage to a corresponding micro-fluid <NUM> to control light transmittance of a region where the micro-fluid is located.

The micro-grooves <NUM> are usually formed on a corresponding carrier. The carrier is, for example, a glass substrate, or a light-transmitting substrate made of light-transmitting resin or light-transmitting polyester compound. Here, specifications of the carrier (e.g., a thickness of the light-transmitting substrate) may be selectively set according to actual needs. For example, the specifications of the carrier are determined after design conditions or process conditions of the optical switch are comprehensively considered. Optionally, an upper surface and a lower surface of the light-transmitting substrate have good flatness and good parallelism.

The plurality of micro-grooves <NUM> are formed in the corresponding carrier by using an etching process, or a plurality of barrier walls are formed on the corresponding carrier, so that the plurality of barrier walls enclose the micro-grooves <NUM>, both of which are allowed. Some embodiments of the present disclosure do not limit a manner in which the micro-grooves <NUM> are formed.

In addition, a shape of a notch of a micro-groove <NUM> may be selectively set according to actual needs. For example, the notch of the micro-groove <NUM> has a rectangular shape, a rhombus shape, a circular shape or other shapes.

It will be added that, a size of the micro-groove <NUM> is in an order of micrometers (µm). That is, the size of the micro-groove <NUM> (e.g., a groove depth, or a groove width) is measured in micrometers as a minimum unit. For example, the groove depth of the micro-groove <NUM> ranges from <NUM> to <NUM>, inclusive.

The micro-fluid <NUM> is disposed in a corresponding micro-groove <NUM>. The region where the micro-fluid <NUM> is located refers to a spatial region in the corresponding micro-groove <NUM> that is configured to accommodate the micro-fluid <NUM>. In a same optical switch, structures of the plurality of micro-grooves <NUM> may be the same or different, both of which are allowed. In addition, the plurality of micro-grooves <NUM> are uniformly distributed or non-uniformly distributed on the carrier, which may be selectively set according to actual needs.

In some examples, the structures of the plurality of micro-grooves <NUM> are the same, and the plurality of micro-grooves <NUM> are distributed in an array on the carrier. That is, a spacing between every two adjacent micro-grooves <NUM> is the same. In some other examples, the plurality of micro-grooves are non-uniformly distributed on the carrier. That is, the carrier has at least two regions, and a distribution density of micro-grooves <NUM> in each region of the at least two regions is different. For example, the carrier has a first region and a second region that have a same area. A number of micro-grooves <NUM> distributed in the first region is different from a number of micro-grooves <NUM> distributed in the second region.

Here, the spacing between two adjacent micro-grooves <NUM> is related to a control accuracy of a light exit region in the optical switch. For example, in an equal-area region, if the spacing between the two adjacent micro-grooves <NUM> is small, a distribution density of micro-grooves <NUM> in this region will be large, which may ensure a high control accuracy of the light exit region in the optical switch.

The micro-fluid <NUM> in each micro-groove <NUM> is correspondingly provided with a driving electrode <NUM>. In some examples not according to the claimed invention, the micro-fluid <NUM> is liquid crystal. By providing voltages of different magnitudes by the driving electrode <NUM>, light transmittance of the corresponding micro-fluid (i.e., the liquid crystal) may be controlled to change. According to the claimed invention, the micro-fluid <NUM> is an electrowetting micro-fluid. By providing voltages of different magnitudes by the driving electrode <NUM>, a contact angle between the corresponding micro-fluid <NUM> (i.e., the electrowetting micro-fluid) and a bottom surface of the groove is capable of being changed, thereby controlling the light transmittance of the region where the micro-fluid <NUM> is located by using a distribution state of the micro-fluid <NUM> in the corresponding micro-groove <NUM>. In some embodiments of the present disclosure, by selecting the electrowetting micro-fluid as the micro-fluid <NUM> in the optical switch, a fast response speed (e.g., a response time of the optical switch that is less than <NUM>) may be obtained, thereby achieving a fast response of the optical switch, i.e., achieving regulation over light that is not observed by human eyes by using the optical switch.

In some embodiments, with reference to <FIG>, the optical switch further includes a first substrate <NUM> and a second substrate <NUM> that are disposed opposite to each other, and a plurality of light-shielding portions <NUM> disposed between the first substrate <NUM> and the second substrate <NUM>. The plurality of light-shielding portions <NUM> enclose the plurality of micro-grooves <NUM> in some embodiments described above on the first substrate <NUM> or the second substrate <NUM>. Here, each light-shielding portion <NUM> is used as a barrier wall corresponding to a micro-groove <NUM>, and a shape, a size, and a material of the light-shielding portion <NUM> may be selectively set according to actual needs. For example, the light-shielding portions <NUM> are a black matrix (abbreviated as BM), which has a simple structure and is easy to manufacture.

After the first substrate <NUM> and the second substrate <NUM> are assembled, and the micro-fluid <NUM> is filled into the corresponding micro-groove <NUM>, through the plurality of light-shielding portions <NUM>, a height of a region where corresponding micro-fluids are located (i.e., a dimension of the region where the micro-fluids are located in a direction perpendicular to the first substrate <NUM>) may be effectively controlled, and light from two adjacent micro-grooves <NUM> is prevented from interfering with each other, so that local dynamic dimming is achieved by using the optical switch, and adverse effects of ambient light and other stray light are effectively prevented. In addition, a height of a region where each micro-fluid is located may also be controlled by combining the light-shielding portions <NUM> with a photo spacer.

In some embodiments, with continued reference to <FIG>, the optical switch further includes at least one support portion <NUM> disposed between the first substrate <NUM> and the second substrate <NUM>. The at least one support portion <NUM> is usually located at an edge of the first substrate <NUM> and is connected to the second substrate <NUM> to support an assembly of the first substrate <NUM> and the second substrate <NUM>, thereby effectively controlling a thickness between the first substrate <NUM> and the second substrate <NUM> (i.e., a spacing between the first substrate <NUM> and the second substrate <NUM>). Here, a shape, a size and a material of a support portion <NUM> may be selectively set according to actual needs. For example, the support portion <NUM> is a photo spacer (abbreviated as PS) made of a photoresist material.

For example, the support portion <NUM> is made of a black photoresist material that is the same as the black matrix. In this way, each support portion <NUM> is made of a same material as the light-shielding portion <NUM>, which is advantageous for simplifying a manufacturing process, reducing a manufacturing cost, and effectively preventing interference of the ambient light.

In some embodiments, the driving electrode <NUM> includes a first electrode <NUM> and a second electrode <NUM>. There are a plurality of ways of arranging the first electrode <NUM> and the second electrode <NUM>, which may be selectively set according to actual needs.

In one example, as shown in <FIG>, the first electrode <NUM> and the second electrode <NUM> are disposed opposite to each other, and a vertical electric field may be formed between the first electrode <NUM> and the second electrode <NUM>. The micro-fluid <NUM> is located between a corresponding first electrode <NUM> and a corresponding second electrode <NUM>. Optionally, the first electrode <NUM> provides a driving voltage signal, the second electrode <NUM> provides a common voltage signal, and the first electrode <NUM> and the second electrode <NUM> are both planar electrodes. In a case where the second electrode <NUM> provides the common voltage signal, second electrodes <NUM> of driving electrodes <NUM> are integrally connected.

In another example, as shown in <FIG>, the first electrode <NUM> and the second electrode <NUM> are disposed to be insulated from each other, and the first electrode <NUM> and the second electrode <NUM> are located at a same side of a corresponding micro-fluid <NUM>, and an arc-shaped electric field may be formed between the first electrode <NUM> and the second electrode <NUM>. For example, the second electrode <NUM>, an insulating medium <NUM> and the first electrode <NUM> are sequentially stacked at a side of the first substrate <NUM> proximate to the micro-fluid <NUM>.

In yet another example, as shown in <FIG> and <FIG>, the driving electrode <NUM> further includes at least one third electrode <NUM> on an inner side wall of each micro-groove <NUM>. In a same driving electrode <NUM>, one of the first electrode <NUM> and the second electrode <NUM> is electrically connected to the at least one third electrode <NUM>, and the other of the first electrode <NUM> and the second electrode <NUM> is insulated from the at least one third electrode <NUM>.

Optionally, in the same driving electrode <NUM>, as shown in <FIG>, the third electrode <NUM> is electrically connected to the first electrode <NUM>, and is insulated from the second electrode <NUM>. Or, as shown in <FIG>, the third electrode <NUM> is electrically connected to the second electrode <NUM>, and is insulated from the first electrode <NUM>. Both arrangements are allowed. Some embodiments of the present disclosure do not limit this.

In addition, the number of the third electrode(s) <NUM> and position(s) thereof on the inner side wall of the micro-groove <NUM> may be selectively set according to actual needs. For example, each micro-groove <NUM> includes four inner side walls enclosing a rectangle, and at least one inner side wall is provided with one third electrode <NUM> thereon. In a case where each inner side wall is provided with a third electrode <NUM> thereon, third electrodes <NUM> are connected to each other to form a single electrode.

The driving electrode <NUM> in some embodiments of the present disclosure includes the first electrode <NUM>, the second electrode <NUM> and the third electrode <NUM>. In this way, control over a multi-directional electric field may be achieved in the micro-groove <NUM>, thereby facilitating to achieve accurate control over the corresponding micro-fluid <NUM> by the driving electrode <NUM>.

In some examples, the first electrode <NUM>, the second electrode <NUM> and the third electrode <NUM> of the driving electrode <NUM> are all transparent electrodes. The first electrode <NUM>, the second electrode <NUM> and the third electrode <NUM> may be made of indium tin oxide (abbreviated as ITO), a metal (e.g., molybdenum (Mo), or silver (Ag)) or other materials. In addition, a thickness of the first electrode <NUM>, a thickness of the second electrode <NUM>, and a thickness of the third electrode <NUM> may be selectively set according to actual needs, as long as requirements for voltages applied to them may be met. In some examples, the thickness of the first electrode <NUM>, the thickness of the second electrode <NUM>, or the thickness of the third electrode <NUM> ranges from <NUM> to <NUM>, inclusive. Typically, the thickness of the first electrode <NUM>, the thickness of the second electrode <NUM>, or the thickness of the third electrode <NUM> ranges from <NUM> to <NUM>, inclusive.

In some embodiments described above, control over the optical switch in a turn-off state, in a turn-on state or in a gated state is related to the material of the micro-fluids <NUM> in the corresponding plurality of micro-grooves <NUM>.

In the claimed invention, as shown in <FIG>, the micro-fluid <NUM> is the electrowetting micro-fluid <NUM>. The electrowetting micro-fluid <NUM> includes a light-transmitting micro-fluid <NUM> and a non-light-transmitting micro-fluid <NUM> that is immiscible with the light-transmitting micro-fluid <NUM>. A contact angle of one of the light-transmitting micro-fluid <NUM> and the non-light-transmitting micro-fluid <NUM> may be changed under driving of a corresponding driving electrode <NUM>.

Here, in the claimed invention where the non-light-transmitting micro-fluid <NUM> is a conductive medium, a contact angle of the non-light-transmitting micro-fluid <NUM> is changed under the driving of the corresponding driving electrode <NUM>.

In some examples not according to the claimed invention, the non-light-transmitting micro-fluid <NUM> is a non-conductive fluid medium, such as oil doped with a plurality of light-shielding particles. Optionally, the non-light-transmitting micro-fluid <NUM> is a light-absorbing micro-fluid, and the light-shielding particles are made of melanin (including natural melanin, synthetic melanin, or oxidized melanin). Correspondingly, the light-transmitting micro-fluid <NUM> is a conductive fluid medium, such as water.

In the claimed invention, the non-light-transmitting micro-fluid <NUM> is a conductive fluid medium. The non-light-transmitting micro-fluid <NUM> includes water and a melanin solute dissolved in water. Here, water is a conductive substance and is immiscible with the light-transmitting micro-fluid <NUM>. The light-transmitting micro-fluid <NUM> is a water-insoluble and non-conductive organic substance, such as gasoline.

In addition, a weight percentage of the melanin solute in the non-light-transmitting micro-fluid <NUM> ranges from <NUM> wt% to <NUM> wt%, inclusive.

It will be noted that, according to different applications of the optical switch, in electrowetting micro-fluids <NUM>, materials of light-transmitting micro-fluids <NUM> may be different, materials of non-light-transmitting micro-fluids <NUM> may be different, and ratios of the light transmitting micro-fluids <NUM> and the non-light-transmitting micro-fluids <NUM> may be also different. That is, the materials and the ratios may be selectively set according to actual needs. Some embodiments of the present disclosure do not limit this.

In a case where the micro-fluid <NUM> is the electrowetting micro-fluid <NUM>, with reference to <FIG> and <FIG>, use of the optical switch will be described below by taking an example not according to the claimed invention in which the light-transmitting micro-fluid <NUM> is water (which is conductive), and the non-light-transmitting micro-fluid <NUM> is the oil doped with the plurality of melanin particles (which is non-conductive).

With reference to <FIG>, in a case where no voltage is applied to each driving electrode <NUM>, surface energy of the light-transmitting micro-fluid <NUM> is the largest, and there is a largest contact angle between the light-transmitting micro-fluid <NUM> and a bottom surface of a corresponding micro-groove <NUM>. That is, the light-transmitting micro-fluid <NUM> is incapable of wetting the bottom surface of the corresponding micro-groove <NUM>. The light-transmitting micro-fluid <NUM> is immiscible with the non-light-transmitting micro-fluid <NUM>. Therefore, under repulsive interaction of the light-transmitting micro-fluid <NUM> and the non-light-transmitting micro-fluid <NUM>, the non-light-transmitting micro-fluid <NUM> and the light-transmitting micro-fluid <NUM> in each micro-groove <NUM> may spread parallel to the bottom surface of the corresponding micro-groove <NUM>. In this way, light entering the optical switch may be absorbed by the non-light-transmitting micro-fluid <NUM> in each micro-groove <NUM>. Therefore, no light passes through the optical switch and then is emitted. That is, the optical switch is in the turn-off state.

With reference to <FIG>, after a voltage is applied to each driving electrode <NUM>, a voltage provided by each driving electrode <NUM> enables the surface energy of the corresponding light-transmitting micro-fluid <NUM> to be reduced. In a case where the light-transmitting micro-fluid <NUM> has the smallest surface energy, there is a smallest contact angle between the light-transmitting micro-fluid <NUM> and the bottom surface of the corresponding micro-groove <NUM>. That is, the light-transmitting micro-fluid <NUM> is capable of wetting the bottom surface of the corresponding micro-groove <NUM>. The light-transmitting micro-fluid <NUM> is immiscible with the non-light-transmitting micro-fluid <NUM>. Therefore, under the repulsive interaction of the light-transmitting micro-fluid <NUM> and the non-light-transmitting micro-fluid <NUM>, the light-transmitting micro-fluid <NUM> in each micro-groove <NUM> may spread parallel to the bottom surface of the corresponding micro-groove <NUM>, and the non-light-transmitting micro-fluid <NUM> is pushed to at least one inner side wall of the corresponding micro-groove <NUM>. In this way, the light entering the optical switch is capable of passing through the light-transmitting micro-fluid <NUM> in each micro-groove <NUM> and then is emitted. That is, the optical switch is in the turn-on state.

The turn-on state or the turn-off state of the optical switch is for the optical switch as a whole. That is to say, in a case where the micro-fluids <NUM> are made of a same material, a same control condition (e.g., a driving voltage) is provided for the micro-fluids <NUM> in the micro-grooves <NUM> in the optical switch, and light transmittance of the regions where the micro-fluids are located will be the same. Of course, if different control conditions are respectively provided for the micro-fluids in different regions in the optical switch, the light transmittance of the regions where the micro-fluids are located will be different. In this way, in the optical switch, one region or a plurality of different regions may be turned on or turned off selectively. That is, the optical switch is in the gated state.

With reference to <FIG>, target regions are selected in the optical switch, and a target region is provided with at least one micro-groove <NUM> therein. A voltage is input to the at least one driving electrode <NUM> in the target region, and light transmittance of a region where a corresponding micro-fluid is located may be controlled by using the at least one driving electrode <NUM>. For example, two target regions are selected in the optical switch, which are a first target region A1 and a second target region A2. After applying a voltage to a driving electrode <NUM> corresponding to each micro-groove <NUM> in the first target region A1 and the second target region A2, a light-transmitting micro-fluid <NUM> corresponding to each micro-groove <NUM> in the two regions (i.e., A1 and A2) spreads out parallel to a bottom surface of a corresponding micro-groove <NUM>, and a non-light-transmitting micro-fluid <NUM> in a same micro-groove <NUM> is pushed to at least one inner side wall of the same micro-groove <NUM>. Thus, the first target region A1 and the second target region A2 in the optical switch are light-transmissive, other regions into which no voltages are applied in the optical switch are non-light- transmissive, and the optical switch is in the gated state.

As such, some embodiments of the present disclosure provide a control method of an optical switch. The control method of the optical switch includes: inputting a voltage to at least one driving electrode in a target region, and controlling light transmittance of a region where a corresponding micro-fluid is located by using the at least one driving electrode. It will be seen that, in some embodiments of the present disclosure, by controlling a gated state of the optical switch, accurate local dynamic dimming may be achieved.

In addition, in some examples, by inputting different voltages to a same driving electrode <NUM> in the target region in a time-sharing manner, a region where a corresponding micro-fluid is located may be controlled to have different light transmittance. That is, a same region may have different light transmittance at different times.

Of course, by inputting different voltages to different driving electrodes <NUM> at a same time, regions where corresponding micro-fluids are located may also be controlled to have different light transmittance. That is, different regions have different light transmittance at the same time. For example, by inputting different voltages to different driving electrodes <NUM> at the same time, light-transmitting micro-fluids <NUM> in corresponding micro-grooves <NUM> will have different surface energy, and distributions of the non-light-transmitting micro-fluids <NUM> in the micro-grooves <NUM> are as shown in <FIG>. That is, under control of the voltages applied to the driving electrodes <NUM>, spreading areas of the non-light-transmitting micro-fluids <NUM> in the micro-grooves <NUM> in a direction parallel to bottom surfaces of the micro-grooves are different. In this way, the regions where the micro-fluids are located will have different luminous flux (i.e., light transmittance).

It will be understood that, in the description of some embodiments described above, being light-transmissive or being non-light-transmissive is not an absolute state. That is, being light-transmissive is not a light exit without light loss, and being non-light-transmissive is not without any light signal. Optionally, being light-transmissive means that corresponding light transmittance is greater than or equal to <NUM>%, and being non-light-transmissive means that a corresponding light transmittance is less than or equal to <NUM>%.

In some other examples not according to the claimed invention, the micro-fluid <NUM> is the liquid crystal <NUM>. A material of the liquid crystal <NUM> may be set according to actual needs.

In some examples not according to the claimed invention, as shown in <FIG>, the liquid crystal <NUM> is twisted nematic (abbreviated as TN) liquid crystal, which may ensure a high response speed of the optical switch.

The driving electrode <NUM> corresponding to the TN liquid crystal in each micro-groove <NUM> includes the first electrode <NUM> and the second electrode <NUM> disposed at two opposite sides of the TN liquid crystal. The first electrode <NUM> is configured to provide a driving voltage signal to the TN liquid crystal, and the second electrode <NUM> is configured to provide a common voltage signal to the TN liquid crystal. The TN liquid crystal is light-transmissive in a non-energized state. With reference to <FIG>, a third target region A3 is selected in the optical switch, and a voltage is input to each driving electrode <NUM> in the third target region A3. In this way, liquid crystal molecules of corresponding TN liquid crystal may be deflected under action of an electric field formed by the driving electrode <NUM>, so that the TN liquid crystal in the third target region A3 is changed from being light-transmissive to being non-light-transmissive. In this way, the third target region A3 in the optical switch is non-light-transmissive, other regions into which no voltages are applied in the optical switch are light-transmissive, and the optical switch is in the gated state.

In some other examples not according to the claimed invention, as shown in <FIG>, the liquid crystal <NUM> is in-plane switching (abbreviated as IPS) liquid crystal or advanced super dimension switch (abbreviated as ADS) liquid crystal.

For example, the liquid crystal <NUM> is the IPS liquid crystal. The driving electrode <NUM> corresponding to the IPS liquid crystal in each micro-groove <NUM> includes the first electrode <NUM> and the second electrode <NUM> disposed at the same side of the IPS liquid crystal. The first electrode <NUM> is configured to provide a driving voltage signal to the IPS liquid crystal, and the second electrode <NUM> is configured to provide a common voltage signal to the IPS liquid crystal. The IPS liquid crystal is non-light-transmissive in the non-energized state. With reference to <FIG>, a fourth target region A4 is selected in the optical switch, and a voltage is input to each driving electrode <NUM> in the fourth target region A4. In this way, liquid crystal molecules of corresponding IPS liquid crystal may be deflected under action of an electric field formed by the driving electrode <NUM>, so that the IPS liquid crystal in the fourth target region A4 is changed from being non-light-transmissive to being light-transmissive. In this way, the fourth target region A4 in the optical switch is light-transmissive, other regions into which no voltages are applied in the optical switch are non-light-transmissive, and the optical switch is in the gated state.

In some embodiments, by controlling each driving electrode <NUM> in a corresponding target region in the optical switch according to requirements for a light exit shape, the light exit region in the optical switch may have a determined shape, such as a circle shape or a rectangle shape, in the gated state according to a fitting shape of the region where the micro-fluid corresponding to the driving electrode <NUM> is located. The greater a distribution density of the micro-grooves <NUM> in the optical switch is, that is, the greater the number of driving electrodes <NUM> in an equal-area region is, the higher a shaping accuracy of the shape of the light exit region in the optical switch that may be controlled by each driving electrode <NUM>, thereby achieving accurate control over the light exit region in the optical switch.

In some other embodiments, the driving electrode <NUM> corresponding to the micro-fluid <NUM> in each micro-groove <NUM> includes the first electrode <NUM> and the second electrode <NUM>. Whether first electrodes <NUM> or second electrodes <NUM> corresponding to different micro-fluids <NUM> are electrically connected is related to voltage signals provided by the first electrodes <NUM> or the second electrodes <NUM>.

In some examples, the first electrode <NUM> provides a driving voltage signal, and the second electrode <NUM> provides a common voltage signal. At least two first electrodes <NUM> are electrically connected. By using a shape of a pattern formed by electrically connecting the at least two first electrodes <NUM>, it may be ensured that the light exit region in the optical switch has a determinate shape when a driving voltage signal is input to the at least two first electrodes. Correspondingly, second electrodes <NUM> corresponding to the at least two first electrodes <NUM> may be electrically connected or may not be electrically connected, both of which are allowed.

For example, as shown in <FIG>, at least two first electrodes <NUM> are electrically connected to form a square electrode. By applying a driving voltage signal to the square electrode, light transmittance of a region where the square electrode is located may be controlled, so that the light exit region in the optical switch has a square shape.

In some other examples, the first electrode <NUM> provides a common voltage signal, and the second electrode <NUM> provides a driving voltage signal. At least two second electrodes <NUM> are electrically connected. By using a shape of a pattern formed by electrically connecting the at least two second electrodes <NUM>, it may be ensured that the light exit region in the optical switch has a determinate shape when a driving voltage signal is input to the at least two second electrodes. Correspondingly, first electrodes <NUM> corresponding to the at least two second electrodes <NUM> may be electrically connected or may not be electrically connected, both of which are allowed.

For example, as shown in <FIG>, at least two second electrodes <NUM> are electrically connected to form an annular electrode. By applying a driving voltage signal to the annular electrode, light transmittance of a region where the annular electrode is located may be controlled, so that the light exit region in the optical switch has an annular shape.

In yet some embodiments, the plurality of micro-grooves <NUM> are distributed in an array. With reference to <FIG>, the optical switch further includes a plurality of first signal lines <NUM> and a plurality of second signal lines <NUM> that are insulated from each other and are crosswise arranged. First electrodes <NUM> in at least one row are electrically connected to a same first signal line <NUM>, and second electrodes <NUM> in at least one column are electrically connected to a same second signal line <NUM>.

A voltage signal input to corresponding first electrodes <NUM> through the first signal line <NUM> and a voltage signal input to corresponding second electrodes <NUM> through the second signal line <NUM> may control light transmittance of a region corresponding to a node where the first signal line <NUM> and the second signal line <NUM> in the optical switch are crosswise arranged. In this way, through the interleaving control of the plurality of first signal lines <NUM> and the plurality of second signal lines <NUM>, the shape of the light exit region of the optical switch may be effectively controlled to be, for example, square, rectangular or circular.

For example, with reference to <FIG>, a fifth target region A5 and a sixth target region A6 are selected in the optical switch. By using voltage signals input through first signal lines <NUM> and second signal lines <NUM> passing through the fifth target region A5, the optical switch may be controlled to have a square light exit region having a same shape as the fifth target region A5. By using voltage signals input through first signal lines <NUM> and second signal lines <NUM> passing through the sixth target region A6, the optical switch may be controlled to have a circular light exit region having a same shape as the sixth target region A6.

Here, the circular shape of the sixth target region A6 that is shown is only an example. In a case where a distribution density of the first signal lines <NUM> and the second signal lines <NUM> is very large, the region corresponding to the node where one first signal line <NUM> and one second signal line <NUM> are crosswise arranged may be regarded as a point. In this way, by controlling light transmittance of the region corresponding to the node where the first signal line <NUM> and the second signal line <NUM> are crosswise arranged in the optical switch, a circular light exit region may be obtained through fitting.

In some embodiments of the present disclosure, the optical switch includes the plurality of micro-grooves <NUM>, the micro-fluid <NUM> disposed in each micro-groove <NUM>, and the driving electrode <NUM> disposed corresponding to the micro-fluid <NUM> in each micro-groove <NUM>. A structure of the optical switch is light and thin, and the optical switch may be applied to a display apparatus having a grating, such as an optical waveguide display apparatus, so as to achieve an ultra-light weight and an ultra-small thickness of the display apparatus. In addition, through separate control over each driving electrode <NUM> in the optical switch, i.e., control over the gated state of the optical switch, the local dynamic dimming may be effectively achieved. In this way, after the optical switch is applied to the display apparatus having the grating or a display apparatus using a pinhole imaging technique, light diffracted from the grating or light exiting from the pinhole is regulated by the optical switch. For example, by using the optical switch to dynamically control a region from which light needs to exit to be light-transmissive, and to control a corresponding region where interference light is located to be non-light-transmissive or to control effective absorption of the interference light, optical crosstalk caused by the Fraunhofer diffraction may be effectively reduced or eliminated, thereby improving a display effect of the display apparatus.

In addition, the optical switch may also be applied to other apparatuses or devices that require dimming, such as an augmented reality (abbreviated as AR)/virtual reality (abbreviated as VR) display apparatus, a smart window, glass, or glasses.

Some embodiments of the present disclosure provide a display apparatus to which the above optical switch is applied.

In some embodiments, with reference to <FIG> and <FIG>, the display apparatus includes the optical switch <NUM> and at least one grating <NUM>. The optical switch <NUM> is located at a light exit side of the at least one grating <NUM>. In this way, light diffracted from the at least one grating <NUM> may accurately exit under gating control of the optical switch <NUM>. For example, by controlling a region facing the at least one grating <NUM> in the optical switch to be light-transmissive, and controlling a region in the optical switch other than the region facing the at least one grating <NUM> to be non-light-transmissive (that is, controlling the corresponding region where the interference light is located to be non-light-transmissive or controlling the effective absorption of the interference light), light exiting through the optical switch <NUM> in the display apparatus may be light required for display (i.e., collimated light diffracted from the grating), thereby reducing or eliminating the effect of the optical crosstalk caused by the Fraunhofer diffraction.

In some examples, if a size and weight of the display apparatus have no adverse effect on a use effect of the display apparatus, for example, the display apparatus is a desktop display apparatus or a monitor, the optical switch <NUM> in some embodiments described above may be directly attached to a corresponding position in the display apparatus as a finished product.

For example, with reference to <FIG>, the display apparatus is an optical waveguide display apparatus. The display apparatus includes: an optical waveguide <NUM>, a backlight source <NUM> disposed at a light incident side of the optical waveguide <NUM>, at least one grating <NUM> disposed at a light exit side of the optical waveguide <NUM>, and the optical switch <NUM> disposed at the light exit side of the at least one grating <NUM>.

Here, each grating <NUM> includes a plurality of sub-gratings. The number of the sub-gratings and a spacing between two adjacent sub-gratings may be set according to actual needs.

In addition, optionally, as shown in <FIG>, the optical waveguide <NUM> is a light guide plate with a refractive index of <NUM>, and the backlight source <NUM> is located at a side of the light guide plate. The display apparatus further includes a reflective layer <NUM> disposed at a side of the optical waveguide <NUM> opposite to the backlight source <NUM>. Light entering from the backlight source <NUM> in the light guide plate is capable of propagating in the light guide plate in a total reflection manner, and is coupled out of a region where each grating <NUM> is located. The reflective layer <NUM> is capable of reflecting the light in the light guide plate to prevent leakage of light signals and effectively improve a light energy utilization rate of the backlight source <NUM>.

With continued reference to <FIG>, the display apparatus further includes a planarization layer <NUM> disposed at a side of the at least one grating <NUM> facing away from the optical waveguide <NUM>. The first substrate <NUM> in the optical switch <NUM> is attached to a surface of the planarization layer <NUM> facing away from the at least one grating <NUM>. The light signals coupled out of the region where each grating <NUM> is located in the display apparatus may exit in a collimated manner under control of the optical switch <NUM>.

It will be worth mentioning that, in the display apparatus, by inputting different voltages to a same driving electrode <NUM> in a target region of the optical switch <NUM> in a time-sharing manner, or by inputting different voltages to different driving electrodes <NUM> in the optical switch <NUM>, a region where a corresponding micro-fluid <NUM> is located may be effectively controlled to have different light transmittance, thereby achieving fast switching of different gray scales in the display apparatus.

For example - not according to the claimed invention - , with reference to <FIG>, the micro-fluid <NUM> is the electrowetting micro-fluid <NUM>, the light transmitting micro-fluid <NUM> in the electrowetting micro-fluid <NUM> is water (which is conductive), and the non-light-transmitting micro-fluid <NUM> is the oil doped with the plurality of melanin particles (which is non-conductive). The first electrode <NUM> in the driving electrode <NUM> provides a driving voltage signal, and the second electrode <NUM> provides a common voltage signal. In this case, by inputting different voltages to different first electrodes <NUM> respectively, different gray scale display may be obtained. Optionally, if a driving voltage input to a first electrode <NUM> is a threshold voltage Vth, a region where a micro-fluid <NUM> corresponding to the first electrode <NUM> is located will have the maximum light transmittance, and a maximum gray scale (e.g., a gray scale with a value of <NUM>) may be correspondingly displayed. If a driving voltage input to a first electrode <NUM> is 0V (i.e., no voltage being applied), a region where a micro-fluid <NUM> corresponding to the first electrode <NUM> is located will be non-light-transmissive, and a minimum gray scale (e.g., a gray scale with a value of <NUM>) may be correspondingly displayed. If a driving voltage input to a first electrode <NUM> is between 0V and Vth, a light transmittance of a region where a micro-fluid <NUM> corresponding to the first electrode <NUM> is located will be between the maximum light transmittance and the minimum light transmittance, and other gray scales between the maximum gray scale and the minimum gray scale may be correspondingly displayed.

In some other examples, if the size and the weight of the display apparatus have a great effect on the use effect of the display apparatus, for example, the display apparatus is a head-mounted display apparatus or a mobile display apparatus, the optical switch <NUM> in some embodiments described above may be integrated onto a display substrate of the display apparatus to achieve the ultra-light weight and the ultra-small thickness of the display apparatus.

For example, with reference to <FIG>, and partial structures in the display apparatus are the same as corresponding structures in the display apparatus shown in <FIG>. Parts with same structures of the two display apparatuses will not be described in detail here, and only differences between the two display apparatuses will be described below.

With continued reference to <FIG>, in the display apparatus, the backlight source <NUM> includes a light bar <NUM> and a reflective cover <NUM>. The light bar <NUM> is disposed in the reflective cover <NUM>, and light emitted by the light bar <NUM> may enter the optical waveguide <NUM> under reflection action of the reflective cover <NUM>. Optionally, the light bar <NUM> is a light-emitting diode (abbreviated as LED) light bar.

In a case where the display apparatus includes the planarization layer <NUM>, the plurality of micro-grooves <NUM> in the optical switch <NUM> may be directly formed in or on a surface of the planarization layer <NUM>. That is, taking the planarization layer <NUM> as the carrier of each micro-groove <NUM> in the optical switch, the optical switch <NUM> is integrated onto the display substrate of the display apparatus to further reduce the thickness of the display apparatus.

In some other embodiments, the display apparatus is the AR/VR display apparatus, which may achieve switching display between the AR and the VR. With reference to <FIG>, the display apparatus includes the optical switch <NUM> and an AR display screen <NUM>. The optical switch <NUM> is located at an ambient light incident side of the AR display screen <NUM>. The AR display screen <NUM> includes an optical waveguide display substrate <NUM> and a display portion <NUM> located at a display light incident side of the optical waveguide display substrate <NUM>. The optical waveguide display substrate <NUM> is provided with a coupling-in grating <NUM> and a coupling-out grating <NUM> therein.

Optionally, an edge of the optical switch <NUM> is adhered to the AR display screen <NUM> through an adhesive layer <NUM>, and an air interlayer <NUM> is disposed between the optical switch <NUM> and the AR display screen <NUM>. In this way, in a case where a refractive index of the first substrate <NUM> in the optical switch <NUM> is the same as or similar to a refractive index of the optical waveguide display substrate <NUM> in the AR display screen <NUM>, it is possible to prevent the optical switch <NUM> from interfering with total reflection of display light signals in the optical waveguide display substrate <NUM> by using the air interlayer <NUM>.

In some examples, with reference to <FIG> and <FIG>, the display light incident side and the ambient light incident side are located on both sides of the optical waveguide display substrate <NUM>, and the display portion <NUM> is a display light source.

When the display apparatus is used to implement AR display, as shown in <FIG>, the optical switch <NUM> is in the turn-on state or the gated state, and ambient light signals are capable of passing through light-transmitting regions in the optical switch <NUM> and entering the AR display screen <NUM>. In this case, after entering the optical waveguide display substrate <NUM> through the coupling-in grating <NUM>, the display light signals emitted by the display light source are capable of propagating in the optical waveguide display substrate <NUM> in a total reflection manner. After passing through the light-transmitting regions in the optical switch <NUM> and entering the optical waveguide display substrate <NUM>, the ambient light signals can merge with the display light signals and enter the human eyes through the coupling-out grating, so that the human eyes may view an AR image combining virtuality and reality.

In addition, optionally, as shown in <FIG>, a region in the optical switch <NUM> facing a peripheral region of the coupling-in grating <NUM> is controlled to be non-light-transmissive, and a region in the optical switch <NUM> facing a peripheral region of the coupling-out grating <NUM> is controlled to be non-light-transmissive. By using a boundary between the light-transmitting regions and the non-light-transmitting regions in the optical switch <NUM>, adverse crosstalk between the ambient light signals and the light diffracted from the gratings may also be effectively reduced.

When the display apparatus is used to implement VR display, as shown in <FIG>, the optical switch <NUM> is in the turn-off state, and the ambient light is incapable of passing through the optical switch <NUM> and entering the AR display screen <NUM>. After entering the optical waveguide display substrate <NUM> through the coupling-in grating <NUM>, the display light signals emitted by the display light source <NUM> are capable of propagating in the optical waveguide display substrate <NUM> in the total reflection manner. Then, the display light signals enter the human eyes through the coupling-out grating <NUM>, so that the human eyes may view a virtual VR image.

In some other examples, with reference to <FIG> and <FIG>, the display light incident side and the ambient light incident side are located on a same side of the optical waveguide display substrate <NUM>. The display portion <NUM> includes a display micro-screen <NUM>, a color filter portion <NUM> and a light collimation portion <NUM> that are sequentially arranged in an incident direction of the display light signals.

When the display apparatus is used to implement the AR display, as shown in <FIG>, the optical switch <NUM> is in the turn-on state or the gated state, and the display light signals and the ambient light signals are both capable of passing through the light-transmitting regions in the optical switch <NUM> and entering the AR display screen <NUM>. In this case, after being filtered by the color filter portion <NUM> and being collimated by the light collimation portion <NUM>, display light signals emitted by the display micro-screen <NUM> pass through the light-transmitting regions in the optical switch <NUM> and enter the optical waveguide display substrate <NUM> through the coupling-in grating <NUM>, and then propagate in the optical waveguide display substrate <NUM> in the total reflection manner. After passing through the light-transmitting regions in the optical switch <NUM> and entering the optical waveguide display substrate <NUM>, the ambient light signals can merge with the display light signals and enter the human eyes through the coupling-out grating, so that the human eyes may view an AR image combining the virtuality and the reality.

When the display apparatus is used to implement VR display, as shown in <FIG>, a region in the optical switch <NUM> facing the coupling-in grating <NUM> is controlled to be light-transmissive, and other regions except for this region are controlled to be non-light-transmissive. In this way, the ambient light signals are incapable of passing through the optical switch <NUM> and entering the AR display screen <NUM>. After being filtered by the color filter portion <NUM> and being collimated by the light collimation portion <NUM>, the display light signals emitted by the display micro-screen <NUM> pass through the light-transmitting region in the optical switch <NUM> and enter the optical waveguide display substrate <NUM> through the coupling-in grating <NUM>. Then, the display light signals propagate in the optical waveguide display substrate <NUM> in the total reflection manner, and finally enter the human eyes through the coupling-out grating, so that the human eyes may view a virtual VR image.

In some embodiments of the present disclosure, the optical switch <NUM> is disposed at the ambient light incident side of the AR display screen <NUM>, so that the display apparatus may be switched between the AR display and the VR display by controlling the optical switch <NUM>, and operation is simple and convenient. In addition, adverse interference caused by grating diffraction or pinhole diffraction in the AR display screen <NUM> may be reduced by dynamically regulating and controlling the optical switch, so as to ensure that the AR display screen <NUM> displays a clear and accurate center image (i.e., an image after the interference caused by the grating diffraction or the pinhole diffraction is removed).

It will be noted that, by using the optical switch to control light effects of coupling-out light signals in a visible range of the human eyes to be substantially the same, the human eyes may view a continuous image with uniform brightness.

In addition, in yet some examples, the display apparatus further includes a human eye tracking sensor located at a display light exit side of the AR display screen <NUM>. In this way, by using the human eye tracking sensor to track a position observed by the human eyes, the optical switch and a turn-on state or a turn-off state of the coupling-in grating and the coupling-out grating in the AR screen <NUM> may be dynamically regulated according to the position observed by the human eyes, thereby considering display effects of maximum light effect (facilitating to view a clear image with high contrast in an outdoor environment) and uniform light exit (ensuring uniform brightness of an entire image).

A structure and use of the human eye tracking sensor may be selectively set according to actual needs. Sizes and positions of regions where the coupling-in grating and the coupling-out grating in the AR screen <NUM> are located may also be selectively set according to actual needs.

In some embodiments described above, driving signals for dynamically regulating the optical switch and driving signals corresponding to the display light signals in the AR display screen are synchronous signals. That is, a size of a light signal coupling-out region, a diffraction intensity of the gratings and a diffraction range of the gratings may be pre-determined through a same controller or processor, thereby outputting the driving signals in real time to dynamically regulate the optical switch, and further reducing the optical crosstalk and the interference caused by the grating diffraction by using the optical switch.

It will be noted that arrows "→" in <FIG> are only used to indicate a transmission direction of light and are not limited to an actual transmission path of the light.

Claim 1:
An optical switch (<NUM>), comprising:
a plurality of micro-grooves (<NUM>);
a micro-fluid (<NUM>) disposed in each micro-groove (<NUM>) of the plurality of micro-grooves (<NUM>); and
a driving electrode (<NUM>) disposed corresponding to the micro-fluid (<NUM>) in each micro-groove (<NUM>), the driving electrode (<NUM>) being configured to provide a voltage to a corresponding micro-fluid (<NUM>) to control light transmittance of a region where the micro-fluid (<NUM>) is located; wherein
the micro-fluid (<NUM>) includes an electrowetting micro-fluid (<NUM>);
the electrowetting micro-fluid (<NUM>) includes a light-transmitting micro-fluid (<NUM>) and a non-light-transmitting micro-fluid (<NUM>) that is immiscible with the light-transmitting micro-fluid (<NUM>), and a contact angle of one of the light-transmitting micro-fluid (<NUM>) and the non-light-transmitting micro-fluid (<NUM>) is capable of being changed under driving of a corresponding driving electrode (<NUM>); characterized in that,
the non-light-transmitting micro-fluid (<NUM>) is a conductive fluid medium and includes water and a melanin solute dissolved in water, and a weight percentage of the melanin solute in the non-light-transmitting micro-fluid (<NUM>) ranges from <NUM> wt% to <NUM> wt%, inclusive, and the light-transmitting micro-fluid (<NUM>) is a water-insoluble and non-conductive organic substance.