Light deflector and light output device including the light deflector

Abstract

The present invention provides a light deflector and a light output device including the light deflector, the light deflector comprising: a first electrode layer and a second electrode layer, which are spaced apart from each other and face each other; and a deflection layer, configured to deflect light incident thereon based on a voltage applied to the first electrode layer and the second electrode layer, wherein the first electrode layer comprises a plurality of electrode elements spaced apart from each other and a resistor that contacts at least part of the plurality of electrode elements and generates a voltage drop therein.

Description

Technical Field

[0001] Example embodiments of the present disclosure relate to a light deflector and a light output device including the light deflector. Background Art

[0002] The holographic display system converts a general image signal into a holographic image signal, and then provides the converted holographic image to both eyes by using an optical system, thereby enabling viewing of 3D images. The optical system can be used to deflect the holographic image to both eyes.

[0003] Typical optical systems for deflecting light may include a micro-electromechanical system (MEMS) scanner, a galvano mirror, a linear spatial light modulator, or a liquid crystal light deflector. In particular, a liquid crystal light deflector having a small volume may be applied to various light output devices. Summary of the invention

[0004] Provided are a light deflector and a light output device including the light deflector.

[0005] Additional aspects will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of example embodiments.

[0006] According to one aspect of an example embodiment, a light deflector is provided, comprising: a first electrode layer and a second electrode layer, which are spaced apart from each other and face each other; and a deflection layer configured to deflect light incident thereon based on a voltage applied to the first electrode and the second electrode, wherein the first electrode layer comprises a plurality of electrode elements spaced apart from each other and a resistor which contacts at least some of the plurality of electrode elements and generates a voltage drop therein.

[0007] The resistor may include a material having electrical conductivity smaller than electrical conductivity of the plurality of electrode elements.

[0008] The resistor may include at least one of a conductive material, a semiconductor material, and an impurity-doped dielectric material.

[0009] An upper surface of the resistor may be in contact with lower surfaces of at least some of the plurality of electrode elements.

[0010] The resistor may include a first region overlapping the plurality of electrode elements and a second region not overlapping the plurality of electrode elements with respect to an incident direction of the incident light.

[0011] A side surface of the resistor may be in contact with side surfaces of at least some of the plurality of electrode elements.

[0012] The resistor may include a plurality of resistance elements disposed alternately with the plurality of electrode elements.

[0013] The plurality of electrode elements may include a first electrode element configured to receive a first voltage, a second electrode element configured to receive a second voltage different from the first voltage, and a third electrode element configured to receive a third voltage different from the first voltage and the second voltage through a resistor.

[0014] The third electrode element may be disposed between the first electrode element and the second electrode element.

[0015] The level of the third voltage may be between the level of the first voltage and the level of the second voltage.

[0016] The light deflector may further include a driving circuit configured to apply the first voltage and the second voltage to the first electrode element and the second electrode element, respectively.

[0017] The driving circuit may include: a first channel configured to output a reference signal of the light deflector; and a second channel configured to output a driving signal of the light deflector.

[0018] The driving circuit may include: a first switching unit, electrically connected to the first channel, the second channel and the first electrode element, and configured to apply any one of a reference signal and a driving signal as a first voltage to the first electrode element; and a second switching unit, electrically connected to the first channel, the second channel and the second electrode element, and configured to apply any one of the reference signal and the driving signal as a second voltage to the second electrode element.

[0019] The first switching unit may include: a first switching element electrically connecting the first channel to the first electrode element; and a second switching element electrically connecting the second channel to the first electrode element.

[0020] The plurality of electrode elements may have a pitch of 20 μm or less.

[0021] The deflection layer may include a plurality of liquid crystal molecules, wherein an orientation of the plurality of liquid crystal molecules may be changed based on an applied voltage.

[0022] According to another aspect of an example embodiment, a light output device is provided, the light output device comprising: a light source configured to emit light; a deflection layer configured to deflect the light emitted by the light source based on an applied voltage; and a first electrode layer and a second electrode layer spaced apart from each other with the deflection layer therebetween, wherein the first electrode layer comprises a plurality of electrode elements arranged spaced apart from each other and a resistor contacting at least some of the plurality of electrode elements and generating a voltage drop therein.

[0023] The resistor may be in contact with lower surfaces of at least some of the plurality of electrode elements.

[0024] The resistor may include a first region overlapping the plurality of electrode elements and a second region not overlapping the plurality of electrode elements with respect to an incident direction of light emitted by the light source.

[0025] The resistor may be in contact with side surfaces of at least some of the plurality of electrode elements.

[0026] The resistor may include a plurality of resistance elements alternately disposed with the plurality of electrode elements.

[0027] The plurality of electrode elements may include a first electrode element configured to receive a first voltage, a second electrode element configured to receive a second voltage different from the first voltage, and a third electrode element disposed between the first electrode element and the second electrode element and configured to receive a third voltage through a resistor, the third voltage being different from the first voltage and the second voltage, respectively.

[0028] The level of the third voltage may be between the level of the first voltage and the level of the second voltage.

[0029] The light output device may be one of a three-dimensional display device and a steering device.

[0030] According to one aspect of an example embodiment, a light deflector is provided, which includes: a first electrode layer, including a plurality of electrode elements spaced apart from each other and a resistor, the resistor being in contact with at least a portion of the plurality of electrode elements and configured to generate a voltage drop; a second electrode layer; a deflection layer, disposed between the first electrode layer and the second electrode layer, and configured to deflect light incident thereon based on a voltage output to the first electrode layer and the second electrode layer; and a driving circuit, including a plurality of channels, the plurality of channels being connected to some of the plurality of electrode elements and configured to output a voltage to the some of the plurality of electrode elements, the number of the plurality of channels being less than the number of the plurality of electrode elements.

[0031] The plurality of electrode elements may include: a first electrode element connected to a first channel among the plurality of channels and configured to receive a first voltage through the first channel; a second electrode element connected to a second channel among the plurality of channels and configured to receive a second voltage different from the first voltage through the second channel; and a third electrode element disposed between the first electrode element and the second electrode element and configured to receive a third voltage through a resistor based on a voltage drop generated by a difference between the first voltage and the second voltage, the third voltage being different from the first voltage and the second voltage, respectively. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The above and / or other aspects will become apparent and more readily understood from the following description of example embodiments in conjunction with the accompanying drawings, in which:

[0033] Figure 1 is a cross-sectional view of a light deflector according to an example embodiment;

[0034] Figure 2 Is used to describe Figure 1 A reference view showing a state where voltages are applied to some of a plurality of electrode elements of a light deflector;

[0035] Figure 3 is a reference view for describing an example of applying a voltage to a light deflector that does not include a resistor;

[0036] Figure 4 is used to describe a method according to an example embodiment Figure 1 A reference view of an example of applying voltages to some of the plurality of electrode elements of a light deflector;

[0037] Figure 5 is a cross-sectional view of a light deflector according to an example embodiment;

[0038] Figure 6 is a cross-sectional view of a light deflector according to an example embodiment;

[0039] Figure 7 shows a light deflector including a driving circuit according to an example embodiment;

[0040] Fig. 8A and Figure 8B Is used to describe Figure 7 Reference view of an example of applying voltage to a light deflector;

[0041] Fig. 9 shows a light output device according to an example embodiment;

[0042] Fig.10 is a cross-sectional view of a schematic structure of a holographic display device including a light deflector according to an example embodiment;

[0043] Fig.11 shows a schematic structure of a holographic display device including a light deflector according to an example embodiment; and

[0044] Fig.12 is a block diagram of a light steering device including a light deflector according to an example embodiment. DETAILED DESCRIPTION

[0045] The example embodiments are described in detail with reference to the accompanying drawings. However, the present disclosure is not limited thereto, and it will be understood that various changes in form and details may be made therein without departing from the spirit and scope of the following claims. That is, only descriptions of specific structures or functions may be given for the purpose of illustrating the example embodiments.

[0046] In a layer structure, when a constituent element is disposed “on” or “over” another constituent element, the constituent element may be merely directly on the other constituent element or over other constituent elements in a non-contact manner.

[0047] Although such terms as "first", "second", etc. may be used to describe various components, such components are not necessarily limited to the above terms. The above terms are only used to distinguish one component from another.

[0048] When used in this specification, the terms "comprising" and / or "comprising..." indicate the presence of the features, integers, steps, operations, elements, components, or combinations thereof, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. Expressions such as "at least one of...", when following a list of elements, modify the entire list of elements without modifying the individual elements in the list. For example, the expression "at least one of a, b, and c" should be understood to include only a, only b, only c, both a and b, both a and c, both b and c, or all a, b, and c.

[0049] Figure 1 is a cross-sectional view of a light deflector 100 according to an example embodiment. Figure 1 , the light deflector 100 may include: a first electrode layer 110 and a second electrode layer 120, which are spaced apart from each other and arranged to face each other; and a deflection layer 130 for deflecting incident light based on a voltage applied to the first electrode layer 110 and the second electrode layer 120. In addition, the light deflector 100 may further include a first substrate 140 and a second substrate 150 supporting the first electrode layer 110 and the second electrode layer 120, respectively.

[0050] The first electrode layer 110 may include a plurality of electrode elements 210 arranged spaced apart from each other and a resistor 220 in contact with the electrode elements 210. The electrode elements 210 may be formed as a blazed grating pattern. For example, the electrode elements 210 may be arranged spaced apart from each other and may each have a strip shape. The electrode elements 210 may be arranged at a specific pitch P in a first direction (e.g., an X-axis direction). For example, the pitch P of the electrode elements 210 may be about 20 μm or less. As the pitch P decreases, the diffraction angle or deflection angle of the light by the light deflector 100 may increase. The electrode elements 210 may have the same width w. The width of the electrode elements 210 may be about 10 μm or less, but the embodiment is not limited thereto. Compared with the first direction, the electrode elements 210 may be formed longer in the second direction (e.g., the Y-axis direction).

[0051] The electrode element 210 may include a transparent conductive material. For example, the electrode element 210 may be formed of indium tin oxide (ITO), indium zinc oxide (IZO), or indium tin zinc oxide (ITZO).

[0052] The resistor 220 may contact the electrode element 210, and a voltage drop may be generated by a voltage applied to the electrode element 210. The resistor 220 may have a flat plate shape in contact with the lower surface of the electrode element 210. For example, the resistor 220 may be disposed between the first substrate 140 and the electrode element 210. Therefore, with respect to the direction in which the incident light travels, a partial area of ​​the resistor 220 may overlap with the electrode element 210, and the remaining area of ​​the resistor 220 may not overlap with the electrode element 210.

[0053] The resistor 220 may include a material having a conductivity smaller than that of the electrode element 210. In addition, the resistor 220 may be formed of a transparent material. The resistor 220 may include at least one of a conductive material, a semiconductor material, and a dielectric material doped with impurities. Therefore, when a voltage is applied to the electrode element 210, a voltage drop may be generated in a remaining region of the resistor 220 disposed between adjacent electrode elements 210, and thus a voltage may be applied to the resistor 220.

[0054] The electrode element 210 may include an effective electrode receiving a voltage from the driving circuit and a dummy electrode receiving a voltage from the resistor 220 instead of receiving a voltage from the driving circuit. The effective electrode and the dummy electrode are described later.

[0055] A voltage (e.g., a reference voltage) may be applied to the second electrode layer 120 for forming an electric field with the first electrode layer 110. The second electrode layer 120 may have a flat plate shape facing the entire portion of the electrode element 210, but the embodiment is not limited thereto. The second electrode layer 120 may be implemented in a form similar to the electrode element 210 of the first electrode layer 110. For example, the second electrode layer 120 may include an electrode element corresponding to the electrode element 210 of the first electrode layer 110. In this state, the same reference voltage may be applied to all electrode elements of the second electrode layer 120.

[0056] The second electrode layer 120 may include a transparent conductive material, such as ITO, IZO, or ITZO.

[0057] The deflection layer 130 may be disposed between the first electrode layer 110 and the second electrode layer 120. The deflection layer 130 may include liquid crystal molecules 131 that change orientation based on an input voltage. The liquid crystal molecules 131 may be initially arranged such that their long axis directions are parallel to one direction, for example, the X-axis direction.

[0058] The liquid crystal molecules 131 may be molecules having positive dielectric anisotropy, but the embodiment is not limited thereto. When a voltage is applied to each of the first electrode layer 110 and the second electrode layer 120, an electric field (E field) may be formed in the deflection layer 130 between the first electrode layer 110 and the second electrode layer 120. Based on the intensity of the E field (that is, the voltage difference between the applied voltages), the liquid crystal molecules 131 may be rotated in their orientation to be parallel to the E field. The phase modulation of the light (L) incident through the first substrate 140 may be caused by using the above effect phase modulation. When the long axis of the liquid crystal molecules 131 rotates in its orientation based on the E field formed between the first electrode layer 110 and the second electrode layer 120, the light deflector 100 deflects the light in a specific direction by forming an electric prism. Although the liquid crystal molecules 131 are described as deflection elements, the embodiment is not limited thereto. Any element other than the liquid crystal molecules 131 may be used, which is capable of deflecting light based on the applied electrical signal.

[0059] The first substrate 140 and the second substrate 150 may include an insulating material and may be transparent. For example, at least one of the first substrate 140 and the second substrate 150 may be formed of glass or transparent plastic.

[0060] Since the voltage corresponds to the width of each electrode element 210, a quantization error may occur. An electric field distortion effect corresponding to the interval between the electrode elements 210 may occur in the deflection layer 130. In order to reduce the electric field distortion effect, it is necessary to reduce the pitch P of the electrode elements 210 or the interval between the electrode elements 210. However, even when the pitch P of the electrode elements 210 or the interval between the electrode elements 210 is reduced in the optical deflector 100, the drive circuit 300 (see Figure 2 ) is limited and is less than the number of electrode elements 210, so it is difficult to apply voltage to all electrode elements 210 of the light deflector 100. Even when the light deflector 100 is integrated, the limited number of channels of the driving circuit 300 makes it difficult to reduce noise and increases the deflection angle.

[0061] In the light deflector 100 according to an example embodiment, since only some of the electrode elements 210 of the first electrode layer 110 receive a voltage from the driving circuit 300 and the remaining electrode elements 210 receive a voltage through the resistor 220, noise may be reduced by reducing a quantization error.

[0062] Figure 2 Is used to describe Figure 1 A reference view showing an example of applying voltage to some of the electrode elements 210 of the light deflector 100. Figure 2As shown, the driving circuit 300 may apply a voltage only to the electrode element arranged at the [3(k-1)+1]th position among the electrode elements 210, where k is a natural number. For example, the driving circuit 300 may apply a voltage to the first electrode layer 110, for example, apply a reference voltage (for example, 0V, which is the same as that applied to the second electrode layer 120) to the first electrode element 210, apply a voltage of 3V to the fourth electrode element, and apply a voltage of 6V to the seventh electrode element 210. Thus, in the deflection layer 130, an E field corresponding to 3V may be formed in a region where the fourth electrode element 210 and the second electrode layer 120 overlap each other, and an E field corresponding to 6V may be formed in a region where the seventh electrode element 210 and the second electrode layer 120 overlap each other. The electrode element 210 to which the voltage is directly applied by the driving circuit 300 may be an effective electrode.

[0063] A voltage drop is generated in the region of the resistor 220 disposed between the first electrode element 210 and the fourth electrode element 210 due to the voltage difference between 0V and 3V, and thus a current flows. A voltage of 1V is applied to the second electrode element 210, and a voltage of 2V is applied to the third electrode element 210. Therefore, in the deflection layer 130, an E field corresponding to 1V may be formed in a region where the second electrode element 210 and the second electrode layer 120 overlap each other, and an E field corresponding to 2V may be formed in a region where the third electrode element 210 and the second electrode layer 120 overlap each other. In this way, although not directly receiving a voltage from the drive circuit 300, the electrode elements (such as the second electrode element and the third electrode element) that receive a voltage due to the voltage drop of the resistor 220 but do not directly receive a voltage from the drive circuit 300 may be dummy electrodes. Since the E field is formed in the region where the dummy electrode and the second electrode layer 120 overlap each other, the E field distortion effect in the deflection layer 130 may be reduced.

[0064] Figure 3 is a reference view for describing an example of applying a voltage to the light deflector 10 that does not include a resistor. Figure 1 The light deflector 100 and Figure 3 When comparing the light deflector 10, Figure 3 The light deflector 10 may not include the resistor 220 . Figure 3 The light deflector 10 may include electrode elements 210 having a constant interval, similar to Figure 1 The light deflector 100. In order to Figure 3 The light deflector 10 is formed with Figure 2 The same E field of the light deflector 100 is used with Figure 2 A driving circuit having a number of channels three times the number of channels of the driving circuit 300. However, it may be difficult to separately manufacture a driving circuit having the same number of channels as the number of electrode elements of the light deflector 10.

[0065] when Figure 2 The driving circuit 300 is applied to Figure 3 When the light deflector 10 is used, in the deflection layer 130, the E field may be formed only in the region overlapping with the electrode element 210 arranged at the [3(k-1)+1]th position, where k is a natural number, and the E zone may not be formed or may be slightly formed in the region overlapping with the electrode element 210 arranged at the [3(k-1)+2]th position (where k is a natural number) and the electrode element 210 arranged at the 3kth position (where k is a natural number). Therefore, an E field distortion effect is generated in the deflection layer 130. As a result, distortion is generated in a considerable portion of the ideal prism shape, and the diffraction efficiency is adversely affected.

[0066] Thus, the light deflector 100 including the resistor 220 can reduce the E field distortion effect caused by using fewer channels of the driving circuit 300 than the number of channels of the electrode element 210. In addition, the resistor 220 can reduce the number of operating channels of the driving circuit 300.

[0067] Figure 4 According to another example embodiment, Figure 1 Reference diagram of some examples of applied voltages in the electrode elements 210 of the light deflector 100. Figure 4 As shown, the driving circuit 300 can apply voltage only to a plurality of electrode elements arranged at the position [9(k-1)+1] (where k is a natural number) and a plurality of electrode elements arranged at the position [9(k-1)+7] (where k is a natural number) among the electrode elements 210. In this state, the electrode element arranged at the position [9(k-1)+1] and the electrode element arranged at the position [9(k-1)+7] can be referred to as an effective electrode, and the remaining electrode elements can be referred to as a dummy electrode. For example, since the driving circuit 300 can provide a reference voltage (e.g., 0V) to the electrode element arranged at the position [9(k-1)+1] and provide a driving voltage (e.g., 6V) to the electrode element arranged at the position [9(k-1)+7], voltages of 1V, 2V, 3V, 4V, and 5V can be sequentially and respectively applied to the electrode element arranged at the position [9(k-1)+2], the electrode element arranged at the position [9(k-1)+3], the electrode element arranged at the position [9(k-1)+4], the electrode element arranged at the position [9(k-1)+5], and the electrode element arranged at the position [9(k-1)+6] due to the voltage drop of the resistor 220. Therefore, only a reference signal and a driving signal having one value are applied without dividing the size of the driving signal, thereby reducing the load of the driving circuit 300.

[0068] Figure 5is a cross-sectional view of a light deflector 100a according to another example embodiment. Figure 5 In the light deflector 100a, Figure 5 The first electrode layer 110a may include a plurality of electrode elements 510 arranged to be spaced apart from each other and a plurality of resistor elements 520 arranged alternately with the electrode elements 510. A side surface of each resistor element 520 may be in contact with a side surface of an adjacent electrode element 510. Therefore, each resistor element 520 may reduce a voltage of one electrode element 510 in contact with one side thereof among the electrode elements 510 and apply the reduced voltage to another electrode element 510 in contact with the other side thereof among the electrode elements 510.

[0069] Figure 6 is a cross-sectional view of a light deflector 100b according to another example embodiment. Figure 6 In the light deflector 100b, Figure 6 The first electrode layer 110b of the present invention may include an electrode element 610 and a resistor 620, wherein the resistor element 610 includes a plurality of effective electrodes 610a arranged spaced apart from each other and a plurality of dummy electrodes 610b arranged spaced apart from the effective electrodes 610a, and the resistor 620 includes a plurality of resistor elements 621 each arranged between adjacent effective electrodes 610a, wherein the dummy electrodes 610b are disposed on the resistor elements 621 and in contact with the resistor elements 621. The side surface of each resistor element 621 may be in contact with the side surface of the effective electrode 610a. The lower surface of each dummy electrode 610b may be in contact with the upper surface of each resistor element 621. Since one of the resistor elements 621 is in contact with only two of the effective electrodes 610a, signal interference between other effective electrodes 610a may be reduced.

[0070] Although the driving circuit 300 for providing voltage to the light deflectors 100, 100a and 100b may include a channel through which the voltage is output to each electrode element electrically connected thereto, the embodiment is not limited thereto. The driving circuit 300 may include a number of channels less than the number of effective electrodes. The channel may include an amplifier.

[0071] Figure 7 FIG. 1 shows a light deflector 100c including a driving circuit 300a according to another example embodiment. Figure 7As shown, the driving circuit 300a may include a first channel 310a through which a reference signal is output, a second channel 310b through which a driving signal having a size different from that of the reference signal is output, and a plurality of switch units 330 electrically connecting the first channel 310a and the second channel 310b to the electrode elements 210. Each switch unit 330 may include: a first switch element SW1 electrically connecting the first channel 310a to a corresponding one of the electrode elements 210; and a second switch element SW2 electrically connecting the second channel 310b to a corresponding one of the electrode elements 210.

[0072] Each of the switch units 330 may cut off at least one of the first switch element SW1 and the second switch element SW2 under the control of the controller 400. For example, each switch unit 330 may turn on the first switch element SW1 and cut off the second switch element SW2 to transmit a reference signal to one of the electrode elements 210 corresponding thereto, and may cut off the first switch element SW1 and turn on the second switch element SW2 to transmit a drive signal to one of the electrode elements 210 corresponding thereto. In addition, by cutting off both the first switch element SW1 and the second switch element SW2, neither the reference signal nor the drive signal is transmitted to a corresponding one of the electrode elements 210. Any electrode element 210 corresponding to the switch unit 330 in which both the first switch element SW1 and the second switch element SW2 are cut off may become a dummy electrode. In other words, the effective electrode and the dummy electrode may change based on the application of a voltage from the drive circuit 300.

[0073] Fig. 8A and Figure 8B Is used to describe Figure 7 Reference view of an example of applying voltage to the light deflector 100c.

[0074] Connecting to Fig. 8A Among the electrode elements 210 of the driving circuit 300, the reference signal V COM can be applied to the electrode element E arranged at its rightmost R , and the driving signal V INPUT can be applied to the electrode element E arranged at its leftmost L Then, a light path changing surface CF1 for deflecting incident light may be formed in the deflection layer 130. The light path changing surface CF1 may be formed by changing the alignment of liquid crystal molecules by a voltage applied between the first electrode layer 110 and the second electrode layer 120.

[0075] like Figure 8B As shown, among the plurality of electrode elements connected to the driving circuit 300a, the reference signal V COMCan be applied to the electrode elements 210 arranged at odd positions, the driving signal V INPUT May be applied to the electrode elements 210 arranged at even-numbered positions. Then, an optical path changing surface CF2 for deflecting incident light may be formed in the deflecting layer 130. Figure 8B The optical path changing surface CF2 shown can deflect the incident light by more than Fig. 8A The light path changing surface CF1 is shown.

[0076] The light deflector according to an example embodiment may be one of constituent elements of the light output device. Fig. 9 FIG. 1 shows a light output device 1000 according to an example embodiment. Fig. 9 As shown, the light output device 1000 may include a light source 1100 for emitting light and a light deflector 1200 for deflecting the light emitted from the light source 1100. The light source 1100 may emit light corresponding to the purpose of the light output device 1000. For example, when the light output device 1000 is a holographic display device, the light source 1100 may be a light source that emits coherent light. When the light output device 1000 is a light redirection device for detecting an external object, the light source 1100 may be a light source that emits light in the infrared range. The above-mentioned light deflectors 100, 100a, 100b, and 100c may be used as the light deflector 1200.

[0077] Fig.10 is a cross-sectional view of a schematic structure of a holographic display device 2000 including a light deflector 2200 according to an example embodiment.

[0078] The holographic display device 2000 may include a light source 2100 for emitting coherent light, a light deflector 2200 for deflecting light emitted from the light source 2100, and a spatial light modulator 2600 for forming a holographic image by diffracting light.

[0079] The holographic display device 2000 may further include: an f-θ lens 2400 that amplifies the light deflected by the light deflector 2200 to a size corresponding to the spatial light modulator 2600 and adjusts the focal track to a plane according to the deflection direction; and a field lens 2500 that focuses the holographic image formed by the spatial light modulator 2600 in space. The arrangement order of the field lens 2500 and the spatial light modulator 2600 is not limited to the arrangement order shown, and the arrangement positions can be interchanged with each other.

[0080] The holographic display device 2000 may also include: an eye tracking sensor 2700 for tracking the position of the viewer's left eye and right eye; and a processor 2800 for controlling the direction in which the light deflector 2200 deflects light and performing computer generated hologram (CGH) calculations for a holographic pattern formed by the spatial light modulator 2600.

[0081] The above-mentioned light deflectors 100, 100a, 100b, and 100c may be used as the light deflector 2200. The light emitted from the light source 2100 is deflected by the light deflector 2200 and incident on the spatial light modulator 2600 via the f-θ lens 2400 and the field lens 2500. The spatial light modulator 2600 may form a holographic pattern having interference fringes for modulating light. When the incident light is diffracted and modulated by the holographic pattern formed by the spatial light modulator 2600, a holographic image may be reproduced at a position in space.

[0082] Fig.11 A schematic structure of a holographic display device 2000a including a light deflector 2200 according to another example embodiment is shown.

[0083] The holographic display device 2000a may include a light source 2100 for emitting coherent light, a light deflector 2200 for deflecting light emitted from the light source 2100, and a spatial light modulator 2600 for forming a holographic image by diffracting incident light. In addition, the holographic display device 2000b may further include: a light guide unit 2300 for guiding the light emitted from the light source 2100 to travel toward the spatial light modulator 2600; and a field lens 2500 for focusing the holographic image in space. The arrangement order of the field lens 2500 and the spatial light modulator 2600 may not be limited to the arrangement order shown, and the arrangement positions may be interchanged with each other.

[0084] The holographic display device 2000a may further include an eye tracking sensor 2700 for tracking the left and right eyes of the viewer and a processor 2800 for controlling the direction in which the light deflector 2200 deflects light and performing CGH calculations for a holographic pattern formed by the spatial light modulator 2600.

[0085] The light deflector 2200 may deflect the light emitted from the light source 2100 to travel in one direction. As the size difference between the light deflector 2200 and the spatial light modulator 2600 increases, Fig.11 Since the holographic display device 2000a according to the example embodiment adopts the light guide unit 2300 that can magnify the light deflected by the light deflector 2200 to fit the size of the spatial light modulator 2600, the length of the holographic display device 2000a in the Z-axis direction can be reduced.

[0086] The light emitted from the light source 2100 may be deflected by the light deflector 2200, and then may be guided by the light guide unit 2300 to be amplified to a size corresponding to the size of the spatial light modulator 2600 and output in a direction toward the spatial light modulator 2600. The light guide unit 2300 may include an input coupler 2320 for allowing the light deflected by the light deflector 2200 to be incident, and an output coupler 2340 for outputting the light traveling through the guidance of the light guide unit 2300.

[0087] The directional light output through the light guide unit 2300 is incident on the spatial light modulator 2600 via the field lens 2500. The spatial light modulator 2600 forms a holographic pattern with interference fringes to modulate the incident light. When the incident light is diffracted and modulated by the holographic pattern formed by the spatial light modulator 2600, a holographic image can be reproduced at a position in space. The left-eye holographic image can be reproduced at the left-eye position, and the right-eye holographic image can be reproduced at the right-eye position.

[0088] The directional light output by the optical deflector 2200 is incident on the spatial light modulator 2600 via the field lens 2500. The spatial light modulator 2600 forms a holographic pattern with interference fringes to modulate the incident light. When the incident light is diffracted and modulated by the holographic pattern formed by the spatial light modulator 2600, a holographic image can be reproduced at a position in space. The first light deflected in the first direction can be used as a holographic light for the left eye, and the second light deflected in the second direction can be used as a holographic light for the right eye.

[0089] The position of the light deflector 2200 in each of the holographic display devices 2000 and 2000a is not limited to Fig.10 and Fig.11 The position of the optical deflector 2200 may be changed in various ways. For example, the optical deflector 2200 may be located between the field lens 2500 and the spatial light modulator 2600, or the spatial light modulator 2600 may be located between the field lens 2500 and the optical deflector 2200.

[0090] Fig.12 3 is a block diagram of a light redirecting device 3000 including a light deflector 3200 according to an example embodiment. The light redirecting device 3000 may include a light source 3100 for emitting light, a light deflector 3200 for deflecting the light emitted from the light source 3100 at a specific angle so as to be output to an external environment, a light detector 3300 for detecting a portion of light reflected or scattered by an object; and a processor 3400, which obtains information about an object existing in the external environment by using the detected light.

[0091] The light source 3100 may be a device for emitting light. For example, the light source 3100 may emit light in the infrared range. When light in the infrared range is used, natural light in the visible range, such as sunlight, may be reduced or prevented from mixing therewith. However, the light emitted from the light source 3100 is not limited to light in the infrared range, and the light source 3100 may emit light in various wavelength ranges. In this case, correction may be required to remove information of the mixed natural light. The above-mentioned light deflectors 100, 100a, 100b, and 100c may be used as the light deflector 3200. Light may be deflected by the light deflector 3200 to be emitted to the external environment.

[0092] The photodetector 3300 can detect a portion of the light reflected or scattered by the object 11. The photodetector 3300 may include one or more pixels. The pixel may be a light receiving element that operates when a bias voltage is applied to the pixel. For example, the photodetector 3300 may include an avalanche photodiode (APD) or a single photon avalanche diode (SPAD). Based on which of the light receiving elements of the APD or SPAD is included, the photodetector 3200 may have different circuit configurations, such as an analog front end (AFE) or a time digital counter (TDC). The distance from the object 11 can be calculated based on the light emission time of the light source 3100 and the light detection time of the photodetector 3300.

[0093] The processor 3400 may obtain information about the object 11 by using the voltage applied by the light detector 3300. The processor 3400 may obtain information about the object 11 by detecting the peak value of the electric signal. The processor 3400 may determine the presence of the object 11 based on the detection of the peak value. In addition, the processor 3400 may determine the distance information from the object 11, that is, the depth information of the object 11, by using the detection time of the detected peak value and the output time of the light output from the light source 3100. In this way, the light deflector 3200 may be applied to various light output devices.

[0094] It should be understood that the example embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects in each example embodiment should typically be considered available for other similar features or aspects in other example embodiments.

[0095] Although example embodiments have been described with reference to the accompanying drawings, workers skilled in the art will understand that various changes in form and details may be made therein without departing from the spirit and scope defined by the following claims.

[0096] This application claims the priority of Korean Patent Application No. 10-2019-0021953 filed on February 25, 2019 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

Claims

1. A light deflector, comprising: a first electrode layer and a second electrode layer, spaced apart from each other and facing each other; and a deflection layer configured to deflect light incident thereon based on a voltage applied to the first electrode layer and the second electrode layer, wherein the first electrode layer includes a plurality of electrode elements arranged to be spaced apart from each other and a resistor that contacts at least part of the plurality of electrode elements and generates a voltage drop therein, The plurality of electrode elements include: a first active electrode configured to receive a first voltage from a driving circuit; a second active electrode configured to receive a second voltage different from the first voltage from the drive circuit; a third effective electrode configured to receive a third voltage from the driving circuit that is different from the first voltage and the second voltage; a first dummy electrode provided between the first effective electrode and the second effective electrode and configured to receive a fourth voltage through the resistor, the fourth voltage being between the first voltage and the second voltage; and a second dummy electrode provided between the second effective electrode and the third effective electrode and configured to receive a fifth voltage through the resistor, the fifth voltage being between the second voltage and the third voltage, wherein the first effective electrode, the first dummy electrode, the second effective electrode, the second dummy electrode and the third effective electrode are arranged in sequence along a first direction, and The electrode element is formed of a transparent conductive material. 2 . The light deflector according to claim 1 , wherein the resistor includes a material having a smaller conductivity than that of the plurality of electrode elements. 3 . The light deflector of claim 1 , wherein the resistor comprises at least one of a conductive material, a semiconductor material, and an impurity-doped dielectric material. 4 . The light deflector according to claim 1 , wherein an upper surface of the resistor is in contact with lower surfaces of at least some of the plurality of electrode elements. 5 . The light deflector according to claim 1 , wherein the resistor includes a first region overlapping with the plurality of electrode elements and a second region not overlapping with the plurality of electrode elements with respect to an incident direction of incident light. 6 . The light deflector according to claim 4 , wherein a side surface of the resistor is in contact with side surfaces of at least some of the plurality of electrode elements.

7. The light deflector according to claim 1, wherein the resistor includes a plurality of resistance elements alternately arranged with the plurality of electrode elements.

8. The light deflector according to claim 1, further comprising: The driving circuit is configured to apply the first voltage, the second voltage, and the third voltage to the first effective electrode, the second effective electrode, and the third effective electrode, respectively.

9. The light deflector according to claim 8, wherein the driving circuit comprises: a first channel configured to output a reference signal of the optical deflector; a second channel configured to output a first driving signal for the optical deflector; as well as The third channel is configured to output a second driving signal for the optical deflector. 10 . The light deflector according to claim 1 , wherein a pitch of the plurality of electrode elements is 20 μm or less.

11. The light deflector according to claim 1, wherein the deflection layer comprises a plurality of liquid crystal molecules, The alignment of the plurality of liquid crystal molecules changes based on an applied voltage.

12. A light output device, comprising: a light source configured to emit light; a deflection layer configured to deflect light emitted by the light source based on an applied voltage; and a first electrode layer and a second electrode layer, arranged at a distance from one another with the deflection layer in between, wherein the first electrode layer includes a plurality of electrode elements arranged spaced apart from each other and a resistor contacting at least some of the plurality of electrode elements and generating a voltage drop therein, The plurality of electrode elements include: a first active electrode configured to receive a first voltage from a driving circuit; a second active electrode configured to receive a second voltage different from the first voltage from the drive circuit; a third effective electrode configured to receive a third voltage from the driving circuit that is different from the first voltage and the second voltage; a first dummy electrode provided between the first effective electrode and the second effective electrode and configured to receive a fourth voltage through the resistor, the fourth voltage being between the first voltage and the second voltage; and a second dummy electrode provided between the second effective electrode and the third effective electrode and configured to receive a fifth voltage through the resistor, the fifth voltage being between the second voltage and the third voltage, wherein the first effective electrode, the first dummy electrode, the second effective electrode, the second dummy electrode and the third effective electrode are arranged in sequence along a first direction, and The electrode element is formed of a transparent conductive material. 13 . The light output device according to claim 12 , wherein the resistor is in contact with lower surfaces of at least some of the plurality of electrode elements. 14 . The light output device according to claim 12 , wherein the resistor includes a first region overlapping with the plurality of electrode elements and a second region not overlapping with the plurality of electrode elements with respect to an incident direction of light emitted by the light source. 15 . The light output device according to claim 13 , wherein the resistor is in contact with side surfaces of at least some of the plurality of electrode elements. 16 . The light output device according to claim 12 , wherein the resistor comprises a plurality of resistance elements alternately arranged with the plurality of electrode elements.

17. A light deflector comprising: a first electrode layer including a resistor and a plurality of electrode elements spaced apart from each other, the resistor being in contact with at least a portion of the plurality of electrode elements and configured to generate a voltage drop; a second electrode layer; a deflection layer disposed between the first electrode layer and the second electrode layer and configured to deflect light incident thereon based on a voltage output to the first electrode layer and the second electrode layer; a driving circuit comprising a plurality of channels connected to some of the plurality of electrode elements and configured to output voltages to the some of the plurality of electrode elements, the number of the plurality of channels being less than the number of the plurality of electrode elements, The plurality of electrode elements include: a first active electrode configured to receive a first voltage from a driving circuit; a second active electrode configured to receive a second voltage different from the first voltage from the drive circuit; a third effective electrode configured to receive a third voltage from the driving circuit that is different from the first voltage and the second voltage; a first dummy electrode provided between the first effective electrode and the second effective electrode and configured to receive a fourth voltage through the resistor, the fourth voltage being between the first voltage and the second voltage; and a second dummy electrode provided between the second effective electrode and the third effective electrode and configured to receive a fifth voltage through the resistor, the fifth voltage being between the second voltage and the third voltage, wherein the first effective electrode, the first dummy electrode, the second effective electrode, the second dummy electrode and the third effective electrode are arranged in sequence along a first direction, and The electrode element is formed of a transparent conductive material.

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