Light guide device and electronic device including same

Abstract

A light guide device according to an embodiment of the present invention comprises: an input diffraction element including a first region having a first grating pattern and a second region having a second grating pattern; a transmission diffraction element including a third region having a third grating pattern and a fourth region having a fourth grating pattern; and an output diffraction element including a fifth region having a fifth grating pattern and a sixth region having a sixth grating pattern, wherein the period of the first grating pattern and the period of the second grating pattern are different from each other, the period of the third grating pattern and the period of the fourth grating pattern are also different from each other, and the period of each grating pattern may be set such that all the wavelengths of light incident on the input diffraction element are propagated.

Description

Light guide device and electronic device including the same

[0001] The present invention relates to a light guide device and an electronic device including the same, and more specifically, to a light guide device including a diffraction element having a plurality of grating patterns and an electronic device including the same, and a light guide device including a diffraction element for changing the direction of leaking light and an electronic device including the same.

[0002] Virtual Reality (VR) refers to a specific environment or situation, or the technology itself, created using artificial technology such as computers that is similar to reality but is not actually real.

[0003] Augmented Reality (AR) refers to a technology that superimposes virtual objects or information onto a real environment to make them appear as if they exist in the original environment.

[0004] Mixed Reality (MR) or Hybrid Reality refers to the creation of new environments or new information by combining the virtual world and the real world. In particular, it is called Mixed Reality when referring to the ability to interact in real time between things existing in the real world and the virtual world.

[0005] In this case, the created virtual environment or situation stimulates the user's five senses and enables spatial and temporal experiences similar to reality, thereby allowing the user to freely cross the boundary between reality and imagination. Furthermore, the user can not only simply immerse themselves in this environment but also interact with the elements implemented within it, such as by using actual devices to perform operations or issue commands.

[0006] Recently, active research is being conducted on equipment (gear, devices) used in these technological fields. However, there is a growing need for miniaturization and improvement of optical performance for such equipment.

[0007] The technical problem that the present invention aims to solve is to provide a light guide device with improved diffraction efficiency and an electronic device including the same.

[0008] In addition, the technical problem that the present invention aims to solve is to provide a light guide device with increased uniformity of light output and an electronic device including the same.

[0009] In addition, the technical problem that the present invention aims to solve is to provide a miniaturized light guide device and an electronic device including the same.

[0010] In addition to this, the technical problems that the present invention aims to solve are not limited to those described above, and other technical problems may exist.

[0011] A light guide device according to an embodiment of the present invention comprises an input diffraction element including a first region having a first grating pattern and a second region having a second grating pattern, a transfer diffraction element including a third region having a third grating pattern and a fourth region having a fourth grating pattern, and an output diffraction element including a fifth region having a fifth grating pattern and a sixth region having a sixth grating pattern, wherein the period of the first grating pattern and the period of the second grating pattern are different from each other, and the period of the third grating pattern and the period of the fourth grating pattern are also different from each other, and the period of each grating pattern can be set so that the wavelength of light incident on the input diffraction element is fully propagated.

[0012] In a light guide device according to an embodiment of the present invention, if the wavelength of light incident on the input diffraction element is set to propagate completely, the wavelength of light incident on the input diffraction element and the period of the grating pattern may all be the same.

[0013] In a light guide device according to an embodiment of the present invention, the period of the fifth grid pattern and the period of the sixth grid pattern may also be different from each other.

[0014] In a light guide device according to an embodiment of the present invention, the azimuth angle of the first grid pattern and the azimuth angle of the second grid pattern are the same, the azimuth angle of the third grid pattern and the azimuth angle of the fourth grid pattern are the same, and the azimuth angle of the fifth grid pattern and the azimuth angle of the fifth grid pattern may be the same.

[0015] In a light guide device according to an embodiment of the present invention, the azimuth angle of the first grid pattern and the azimuth angle of the second grid pattern are different from each other, the third region and the fourth region are physically separated and arranged, the azimuth angle of the third grid pattern and the azimuth angle of the fourth grid pattern are different from each other, and the azimuth angle of the fifth grid pattern and the azimuth angle of the sixth grid pattern may be different from each other.

[0016] In a light guide device according to an embodiment of the present invention, the output diffraction element may be positioned between the third region and the fourth region of the transfer diffraction element.

[0017] In a light guide device according to an embodiment of the present invention, the azimuth angle of the first grating pattern and the azimuth angle of the second grating pattern are different from each other, the third region and the fourth region are physically separated and arranged, the azimuth angle of the third grating pattern and the azimuth angle of the fourth grating pattern are different from each other, and the output diffraction element is arranged on one side of the third region and the fourth region of the transfer diffraction element so that the period and azimuth angle of the fifth grating pattern may be the same as the period and azimuth angle of the sixth grating pattern.

[0018] In a light guide device according to an embodiment of the present invention, the first to sixth regions may be composed of a plurality of sub-regions.

[0019] In a light guide device according to an embodiment of the present invention, the size of the cell in the fifth region and the size of the cell in the sixth region may be smaller than the size of the eye box.

[0020] A light guide device according to an embodiment of the present invention comprises a substrate, an input diffraction element, a transfer diffraction element, an output transfer element, and a redirecting diffraction element disposed on the substrate, wherein the input diffraction element diffracts light incident from outside the substrate and emits it to the transfer diffraction element, the transfer diffraction element diffracts light incident to the transfer diffraction element and emits it to the output diffraction element, the output diffraction element diffracts light incident from the transfer diffraction element and emits it to outside the substrate, and the redirecting diffraction element can diffract light incident from the input diffraction element or the transfer diffraction element and emit it.

[0021] In a light guide device according to an embodiment of the present invention, the redirecting diffraction element is positioned in a direction opposite to the direction in which the transfer diffraction element is positioned relative to the input diffraction element, so as to diffract light incident from the input diffraction element and send it out to the input diffraction element.

[0022] In a light guide device according to an embodiment of the present invention, the redirecting diffraction element includes a grating pattern, and the period of the grating pattern of the redirecting diffraction element may be half the period of the grating pattern of the input diffraction element.

[0023] In the light guide device according to an embodiment of the present invention, the shape of the redirecting diffraction element may be symmetrical with respect to the shape of the transfer diffraction element with respect to the input diffraction element.

[0024] In a light guide device according to an embodiment of the present invention, the redirecting diffraction element comprises at least one of a first redirecting diffraction element and a second redirecting diffraction element, wherein the first redirecting diffraction element is positioned in a direction opposite to the direction in which the input diffraction element is positioned relative to the transfer diffraction element, and diffracts the incident light emitted from the transfer diffraction element and emits it to the transfer diffraction element, and the second redirecting diffraction element is positioned in a direction opposite to the direction in which the output diffraction element is positioned relative to the transfer diffraction element, and diffracts the incident light emitted from the transfer diffraction element and emits it to the output diffraction element.

[0025] In a light guide device according to an embodiment of the present invention, the first redirecting diffraction element includes a first grating pattern, and the period of the first grating pattern of the first redirecting diffraction element is half the period of the grating pattern of the input diffraction element, and the second redirecting diffraction element includes a second grating pattern, and the period of the second grating pattern of the second redirecting diffraction element may be half the period of the grating pattern of the output diffraction element.

[0026] In a light guide device according to an embodiment of the present invention, the shape of the first redirecting diffraction element may be a shape in which the shape of the transfer diffraction element is extended in a direction opposite to the direction in which the input diffraction element is arranged.

[0027] In the light guide device according to an embodiment of the present invention, the shape of the second redirecting diffraction element may be a shape in which the shape of the transfer diffraction element is extended in a direction opposite to the direction in which the output diffraction element is arranged.

[0028] In a light guide device according to an embodiment of the present invention, the redirecting diffraction element includes a grating pattern, and the shape of the grating pattern may be one of slant, binary, and trapezoid.

[0029] In the light guide device according to an embodiment of the present invention, the shape of the redirecting diffraction element may be one of a rectangle, a triangle, a trapezoid, and a parallelogram.

[0030] In the light guide device according to an embodiment of the present invention, the shape of the redirecting diffraction element may be part of one of a rectangle, a triangle, a trapezoid, and a parallelogram.

[0031] In the light guide device according to an embodiment of the present invention, the redirecting diffraction element may be metal-coated.

[0032] A light guide device according to an embodiment of the present invention comprises a substrate, an input diffraction element, an output transmission element, and a redirecting diffraction element disposed on the substrate, wherein the input diffraction element diffracts light incident from outside the substrate and emits it to the output diffraction element, the output diffraction element diffracts light incident from the input diffraction element and emits it to outside the substrate, and the redirecting diffraction element diffracts light incident from the input diffraction element and emits it to the output diffraction element.

[0033] In a light guide device according to an embodiment of the present invention, the redirecting diffraction element is positioned in a direction opposite to the direction in which the output diffraction element is positioned relative to the input diffraction element, so as to diffract light incident from the input diffraction element and output it to the output diffraction element.

[0034] According to an embodiment of the present invention, the efficiency and uniformity with respect to the wavelength of light in a light guide device can be increased.

[0035] According to an embodiment of the present invention, the generation of a ghost image can be prevented by separating regions with different grating patterns of diffraction elements in a light guide device.

[0036] According to an embodiment of the present invention, light that is not transmitted to the eye box from the light guide device can be diffracted again and transmitted to the eye box.

[0037] According to an embodiment of the present invention, light that is not transmitted from the light guide device to the eye box can be transmitted again, thereby increasing the efficiency and uniformity of the light.

[0038] In addition to these, the effects obtainable from the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art to which the present invention belongs from the description below.

[0039] FIG. 1 is a block diagram showing the configuration of an electronic device (10) including a light guide device according to an embodiment of the present invention.

[0040] FIG. 2 is a perspective view of an electronic device including a light guide device according to an embodiment of the present invention.

[0041] FIG. 3 is a schematic diagram of a light guide device according to an embodiment of the present invention.

[0042] FIG. 4 is a diagram showing the grating pattern of a diffraction element of a light guide device according to an embodiment of the present invention.

[0043] FIG. 5a is a diagram showing the arrangement of diffraction elements included in a light guide device according to a first embodiment of the present invention.

[0044] FIGS. 5B and FIGS. 5C are diagrams showing the NA space of light passing through a diffraction element including a plurality of regions exemplified in FIG. 5A.

[0045] FIG. 6 is a diagram showing the arrangement of diffraction elements included in a light guide device according to a second embodiment of the present invention.

[0046] FIG. 7 is a diagram showing the arrangement of diffraction elements included in a light guide device according to a third embodiment of the present invention.

[0047] FIGS. 8a to 8c are drawings showing various examples of an input diffraction element including a plurality of regions according to an embodiment of the present invention.

[0048] FIGS. 9a and 9b are drawings illustrating various examples of a transfer diffraction element or an output diffraction element including a plurality of regions according to an embodiment of the present invention.

[0049] FIG. 10a is a diagram showing the path of light from a plurality of diffraction elements included in an optical guide device, and FIG. 10b is a diagram showing this in NA space.

[0050] FIG. 11a is a diagram showing the path of light in a diffraction element included in a light guide device according to the first embodiment of the present invention.

[0051] FIG. 11b is a side view of the path of light that is not incident on the transfer diffraction element among the light emitted from the input diffraction element in a light guide device according to the first embodiment of the present invention.

[0052] FIG. 11c is a diagram showing the path of light in the NA space in a light guide device according to the first embodiment of the present invention.

[0053] FIGS. 12a and FIGS. 12b are drawings showing examples of various shapes of a redirecting diffraction element included in a light guide device according to the first embodiment of the present invention.

[0054] FIG. 13a is a diagram showing the path of light in a diffraction element included in a light guide device according to a second embodiment of the present invention.

[0055] FIG. 13b is a diagram showing, as an example, the path of light in NA space in a light guide device according to a second embodiment of the present invention.

[0056] FIGS. 14a to 14d are drawings showing various examples of a first redirecting diffraction element and a second redirecting diffraction element included in a light guide device according to a second embodiment of the present invention.

[0057] FIG. 15a is a diagram showing the path of light in a diffraction element included in a light guide device according to a third embodiment of the present invention, and FIG. 15b is a diagram showing this in NA space.

[0058] FIGS. 16a and FIGS. 16b are drawings showing examples of various shapes of a redirecting diffraction element included in a light guide device according to a third embodiment of the present invention.

[0059] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

[0060] However, the technical concept of the present invention is not limited to some of the described embodiments but can be implemented in various different forms, and within the scope of the technical concept of the present invention, one or more of the components among the embodiments may be selectively combined or substituted.

[0061] In addition, terms used in the embodiments of the present invention (including technical and scientific terms) may be interpreted in a sense that is generally understood by those skilled in the art to which the present invention belongs, unless explicitly and specifically defined otherwise. Terms that are commonly used, such as terms defined in advance, may be interpreted in consideration of their meaning in the context of the relevant technology.

[0062] Furthermore, the terms used in the embodiments of the present invention are for the purpose of describing the embodiments and are not intended to limit the present invention.

[0063] In this specification, the singular form may include the plural form unless specifically stated otherwise in the text, and when described as "at least one of A and B and C (or more than one)," it may include one or more of all combinations that can be formed from A, B, and C.

[0064] In addition, terms such as first, second, A, B, (a), (b), etc. may be used when describing the components of the embodiments of the present invention.

[0065] These terms are intended merely to distinguish a component from other components and are not limited by the nature, order, sequence, etc., of the said component.

[0066] And, where it is stated that a component is 'connected', 'combined', or 'joined' to another component, this may include not only cases where the component is directly connected, combined, or joined to the other component, but also cases where it is 'connected', 'combined', or 'joined' due to another component located between the component and the other component.

[0067] Furthermore, when described as being formed or placed "above or below" each component, "above" or "below" includes not only cases where two components are in direct contact with each other, but also cases where one or more other components are formed or placed between the two components. Additionally, when expressed as "above or below," it may include the meaning of a downward direction as well as an upward direction relative to a single component.

[0068] Extended Reality (XR) is a collective term for Virtual Reality (VR), Augmented Reality (AR), and Mixed Reality (MR). VR technology provides real-world objects or backgrounds solely as CG images, AR technology provides virtual CG images superimposed on real-world images, and MR technology provides virtual objects mixed and combined with the real world.

[0069] MR technology is similar to AR technology in that it displays real-world objects and virtual objects together. However, there is a difference in that while virtual objects in AR technology are used to complement real-world objects, virtual objects and real-world objects are used as equals in MR technology.

[0070] XR technology can be applied to HMDs (Head-Mount Displays), HUDs (Head-Up Displays), mobile phones, tablet PCs, laptops, desktops, TVs, digital signage, etc., and devices to which XR technology is applied can be called XR devices.

[0071] Hereinafter, an electronic device providing augmented reality according to an embodiment of the present invention will be described. In particular, a projection device applied to augmented reality and an electronic device including the same will be described in detail.

[0072] FIG. 1 is a block diagram showing the configuration of an electronic device (10) including a light guide device according to an embodiment of the present invention.

[0073] Referring to FIG. 1, an electronic device (10) including a light guide device may include a wireless communication unit (11), an input unit (12), a sensing unit (13), an output unit (14), an interface unit (15), a memory (16), a control unit (17), and a power supply unit (18), etc. Since the components illustrated in FIG. 1 are not essential for implementing the electronic device (10), the electronic device (10) described herein may have more or fewer components than those listed above.

[0074] More specifically, among the above components, the wireless communication unit (11) may include one or more modules that enable wireless communication between the electronic device (10) and a wireless communication system, between the electronic device (10) and another electronic device, or between the electronic device (10) and an external server. Additionally, the wireless communication unit (11) may include one or more modules that connect the electronic device (10) to one or more networks.

[0075] This wireless communication unit (11) may include at least one of a broadcast reception module, a mobile communication module, a wireless internet module, a short-range communication module, and a location information module.

[0076] The input unit (12) may include a camera or video input unit for inputting a video signal, a microphone or audio input unit for inputting an audio signal, and a user input unit for receiving information from a user (e.g., a touch key, a mechanical key, etc.). Voice data or image data collected from the input unit (12) may be analyzed and processed into a user's control command.

[0077] The sensing unit (13) may include one or more sensors for detecting at least one of information within the electronic device (10), information about the surrounding environment surrounding the electronic device (10), and user information.

[0078] For example, the sensing unit (13) may include at least one of a proximity sensor, an illumination sensor, a touch sensor, an acceleration sensor, a magnetic sensor, a gravity sensor (G-sensor), a gyroscope sensor, a motion sensor, an RGB sensor, an infrared sensor (IR sensor: infrared sensor), a fingerprint sensor (finger scan sensor), an ultrasonic sensor, an optical sensor (e.g., a shooting means), a microphone, a battery gauge, an environmental sensor (e.g., a barometer, a hygrometer, a thermometer, a radiation detection sensor, a heat detection sensor, a gas detection sensor, etc.), and a chemical sensor (e.g., an electronic nose, a healthcare sensor, a biometric sensor, etc.). Meanwhile, the electronic device (10) disclosed in this specification may utilize information detected by at least two of these sensors in combination.

[0079] The output unit (14) is intended to generate output related to sight, hearing, or touch, and may include at least one of a display unit, an audio output unit, a haptic module, and an optical output unit. The display unit may form a layered structure with the touch sensor or be formed integrally to implement a touch screen. Such a touch screen functions as a user input means that provides an input interface between the electronic device (10) and the user, and at the same time can provide an output interface between the electronic device (10) and the user.

[0080] The interface section (15) serves as a channel for various types of external devices connected to the electronic device (10). Through the interface section (15), the electronic device (10) can receive content from the external device and interact by exchanging various input signals, sensing signals, and data.

[0081] For example, the interface section (15) may include at least one of a wired / wireless headset port, an external charger port, a wired / wireless data port, a memory card port, a port for connecting a device equipped with an identification module, an audio I / O (Input / Output) port, a video I / O (Input / Output) port, and an earphone port.

[0082] Additionally, the memory (16) stores data that supports various functions of the electronic device (10). The memory (16) can store a number of applications (application programs or applications) running on the electronic device (10), data for the operation of the electronic device (10), and instructions. At least some of these applications may be downloaded from an external server via wireless communication. Additionally, at least some of these applications may exist on the electronic device (10) from the time of shipment for the basic functions of the electronic device (10) (e.g., phone incoming and outgoing functions, message receiving and outgoing functions).

[0083] In addition to operations related to the application, the control unit (17) can generally control the overall operation of the electronic device (10). The control unit (17) can process signals, data, information, etc. that are input or output through the components described above.

[0084] Additionally, the control unit (17) can control at least some of the components by running an application program stored in the memory (16) to provide appropriate information to the user or process functions. Furthermore, the control unit (17) can operate at least two or more of the components included in the electronic device (10) in combination with each other to run the application program.

[0085] Additionally, the control unit (17) can detect the movement of the electronic device (10) or the user by using a gyroscope sensor, gravity sensor, motion sensor, etc. included in the sensing unit (13). Alternatively, the control unit (17) can detect an object approaching the electronic device (10) or the user by using a proximity sensor, light sensor, magnetic sensor, infrared sensor, ultrasonic sensor, light sensor, etc. included in the sensing unit (13). Furthermore, the control unit (17) can also detect the movement of the user through sensors provided in a controller that operates in conjunction with the electronic device (10).

[0086] In addition, the control unit (17) can perform the operation (or function) of the electronic device (10) using an application program stored in the memory (16).

[0087] The power supply unit (18) can supply power to each component included in the electronic device (10) by receiving external power or internal power under the control of the control unit (17). The power supply unit (18) includes a battery, and the battery may be provided in a built-in or replaceable form.

[0088] At least some of the above components may operate in cooperation with each other to implement the operation, control, or control method of an electronic device according to various embodiments described below. Additionally, the operation, control, or control method of an electronic device may be implemented on the electronic device by running at least one application program stored in memory (16).

[0089] Hereinafter, an electronic device including a light guide device described as an example of the present invention is described based on an embodiment applied to a Head Mounted Display (HMD).

[0090] FIG. 2 is a perspective view of an electronic device including a light guide device according to an embodiment of the present invention.

[0091] As illustrated in FIG. 2, an electronic device according to an embodiment of the present invention may include a frame (100), a project device (200), and a display unit (300).

[0092] The electronic device may be of the smart glass type. The smart glass type electronic device is configured to be wearable on the head of the human body and may be provided with a frame (case, housing, etc.) (100) for this purpose. The frame (100) may be formed of a flexible material to facilitate wearing.

[0093] The frame (100) is supported on the head and provides a space for mounting various components. As illustrated, electronic components such as a projector (200), a user input unit (130), or an audio output unit (140) may be mounted on the frame (100). Additionally, a lens covering at least one of the left and right eyes may be detachably mounted on the frame (100).

[0094] As shown in the drawing, the frame (100) may have the form of glasses worn on the face of the user, but is not necessarily limited thereto and may have the form of goggles worn in close contact with the user's face.

[0095] Such a frame (100) may include a front frame (110) having at least one opening, and a pair of side frames (120) that extend in the y direction (in FIG. 2) intersecting the front frame (110) and are parallel to each other.

[0096] The frame (100) may have the same or different length (D1) in the x direction and length (L1) in the y direction.

[0097] The projection device (200) is configured to control various electronic components equipped in an electronic device. The projection device (200) may be used interchangeably with 'light output device', 'light projection device', 'light irradiation device', 'optical device', etc.

[0098] The projection device (200) can generate an image or a continuous video of images that is displayed to the user. The projection device (200) may include an image source panel that generates an image and a plurality of lenses that diffuse and converge the light generated from the image source panel.

[0099] The project device (200) may be fixed to one of the two side frames (120). For example, the project device (200) may be fixed to the inside or outside of one of the side frames (120), or may be formed integrally by being embedded inside one of the side frames (120). Alternatively, the project device (200) may be fixed to the front frame (110) or provided separately from the electronic device.

[0100] The display unit (300) can be implemented in the form of a head-mounted display (HMD). A head-mounted display refers to a display method that is mounted on the head and displays an image directly in front of the user's eyes. In order to provide an image directly in front of the user's eyes when the user wears the electronic device, the display unit (300) may be positioned to correspond to at least one of the left eye and the right eye. In this drawing, the display unit (300) is exemplified as being located in the part corresponding to the right eye so as to output an image toward the user's right eye. However, as described above, it is not limited to this and may be positioned on both the left eye and the right eye.

[0101] The display unit (300) can allow the user to visually perceive the external environment while simultaneously displaying an image generated by the projection device (200) to the user. For example, the display unit (300) can project an image onto a display area using a prism.

[0102] And the display unit (300) may be formed to be transparent so that the projected image and the general field of view in front (the range the user looks at through their eyes) can be seen simultaneously. For example, the display unit (300) may be translucent and may be formed of an optical member including glass.

[0103] The display unit (300) may be inserted into and fixed to an opening included in the front frame (110), or positioned on the back of the opening [i.e., between the opening and the user] and fixed to the front frame (110). Although the drawing illustrates an example where the display unit (300) is positioned on the back of the opening and fixed to the front frame (110), the display unit (300) may be positioned and fixed at various locations on the frame (100).

[0104] As shown in FIG. 2, when an image light for an image is incident on one side of a display unit (300) from a projection device (200), the image light is emitted through the display unit (300) to the other side, thereby allowing the image generated by the projection device (200) to be shown to the user.

[0105] Accordingly, the user can view the external environment through the opening of the frame (100) while simultaneously viewing the image generated by the projection device (200). That is, the image output through the display unit (300) can be seen overlapping with the normal field of view. The electronic device can utilize these display characteristics to provide Augmented Reality (AR), which superimposes a virtual image onto a real image or background to display it as a single image.

[0106] Furthermore, in addition to this operation, the external environment and the image generated by the projection device (200) may be provided to the user with a time difference for a short period that is not perceived by the user. For example, within a single frame, the external environment may be provided to the user in one section, and the image from the projection device (200) may be provided to the user in another section. Alternatively, both overlap and time difference may be provided.

[0107] The display unit below may be represented as a light guide device. The light guide device according to the embodiment may correspond to the display unit included in the electronic device described above.

[0108] The first direction below may correspond to the X-axis direction on the drawing, and the second direction may correspond to the Y-axis direction on the drawing. The first direction and the second direction may be directions perpendicular to each other. Additionally, the third direction may be the opposite direction to the second direction. The first direction, the second direction, and the third direction may be directions perpendicular to the optical axis direction.

[0109] FIG. 3 is a schematic diagram of a light guide device according to an embodiment of the present invention.

[0110] Referring to FIG. 3, the light guide device (300) according to the embodiment may include a substrate (310), an input diffraction element (320), a transfer diffraction element (330), and an output diffraction element (340). Additionally, the light guide device (300) may include a cover (350).

[0111] The light guide device (300) can change the path of the incident light output from the projector device (200) and output the light to the outside again. The light can be sequentially incident on an input diffraction element, a substrate, a transfer diffraction element, and an output diffraction element and output to the outside again. The direction of incidence of the light to the light guide device (300) may be a third direction. The third direction may mean the direction of incidence of the light or the opposite direction. Additionally, the third direction may mean the direction of the optical axis.

[0112] The substrate (310) can serve as a path for transmitting light. The substrate (310) can transmit light. An input diffraction element (320), a transfer diffraction element (330), and an output diffraction element (340) may be disposed on the substrate (310). Light may travel along the interior of the substrate (310) by total internal reflection. The input diffraction element (320), the transfer diffraction element (330), and the output diffraction element (340) may be disposed spaced apart from each other on the substrate (310). The substrate (310) may be disposed in a second direction.

[0113] The input diffraction element (320) can serve as a path for incident light. The input diffraction element (320) can be placed on the substrate (310). Light can be incident from the outside through the input diffraction element (320) to the light guide device (300) and transmitted through the substrate (310). The input diffraction element (320) can change the path of the light by diffracting the light. The input diffraction element (320) can be placed adjacent to the transmission diffraction element (330). Light diffracted from the input diffraction element (320) can be transmitted through the substrate (310) and reach the transmission diffraction element (330).

[0114] The transfer diffraction element (330) can change the path of light. The transfer diffraction element (330) can be placed on the substrate (310). The transfer diffraction element (330) can change the path of light incident through the input diffraction element (320). The transfer diffraction element (330) can change the path of light so that it is directed toward the output diffraction element (340). The transfer diffraction element (330) can change the path of light by diffracting the light. The transfer diffraction element (330) can be placed between the input diffraction element (320) and the output diffraction element (340) in the path of light.

[0115] The output diffraction element (340) can serve as a path for light to be emitted. The output diffraction element (340) can be placed on the substrate (310). Light can be emitted to the outside of the light guide device (300) through the output diffraction element (340). The output diffraction element (340) can receive light with a changed path from the transfer diffraction element (330) and emit it to the outside. The output diffraction element (340) can change the path of the light and emit it to the outside. The output diffraction element (340) can change the path of the light by diffracting the light.

[0116] A cover (350) may be placed on a substrate (310), an input diffraction element (320), a transfer diffraction element (330), and an output diffraction element (340). The cover (350) may be placed adjacent to a projector device (200) on the substrate (310), the input diffraction element (320), the transfer diffraction element (330), and the output diffraction element (340). Light irradiated by the projector device (200) may pass through the cover (350) and be incident on the input diffraction element (320). The cover (350) may have the effect of protecting the interior of the light guide device (300).

[0117] FIG. 4 is a diagram showing the grating pattern of a diffraction element of a light guide device according to an embodiment of the present invention.

[0118] Referring to FIG. 4, the input diffraction element (320), the transfer diffraction element (330), and the output diffraction element (340) may each have a grating pattern in which a plurality of protrusions are repeatedly arranged. The plurality of protrusions may have a constant width, period, and height and may be arranged on the input diffraction element (320), the transfer diffraction element (330), and the output diffraction element (340). The plurality of protrusions may protrude in the direction of the optical axis on the input diffraction element (320), the transfer diffraction element (330), and the output diffraction element (340). The plurality of protrusions may be spaced apart in the vector direction of the pattern containing the protrusions. Depending on the width, period, and height of the plurality of protrusions, the path of light may change differently after passing through the input diffraction element (320), the transfer diffraction element (330), and the output diffraction element (340). The grating period (or period) of a diffraction element can be defined as the shortest distance between one side of a protrusion and one side of an adjacent protrusion. The grating period of a diffraction element can be the shortest distance between identical sides of a protrusion.

[0119] The grating vector of the diffraction element may be the direction of separation of adjacent protrusions of the diffraction element. Additionally, the magnitude of the grating vector may be the angle (i.e., azimuth) that the grating vector makes with the first direction. The first direction is perpendicular to the optical axis direction and may be the direction in which the input diffraction element (320) is separated from the output diffraction element (340). For example, the first direction may be the horizontal direction in which the substrate is placed. The first direction may refer to the X-axis direction of FIG. 4.

[0120] The input diffraction element (320) may include a plurality of first protrusions (321). The grating period (λ1) of the input diffraction element (320) may be the shortest distance between one side of the first protrusion (321) and one side of the adjacent first protrusion (321). Additionally, the grating period (λ1) of the input diffraction element (320) may be the shortest distance between the same sides of adjacent first protrusions (321). The grating vector (φ1) of the input diffraction element (320) may be the direction of separation of the adjacent first protrusions (321) of the input diffraction element (320). The magnitude of the grating vector (φ1) of the input diffraction element (320) may be the angle formed by the grating vector (φ1) of the input diffraction element (320) with the first direction.

[0121] The transfer diffraction element (330) may include a plurality of second protrusions (331). The grating period (λ2) of the transfer diffraction element (330) may be the shortest distance between one side of the second protrusion (331) and one side of the adjacent second protrusion (331). Additionally, the grating period (λ2) of the transfer diffraction element (330) may be the shortest distance between the same sides of adjacent second protrusions (331). The grating vector (φ2) of the transfer diffraction element (330) may be the direction of separation of the adjacent second protrusions (331) of the transfer diffraction element (330). The magnitude of the grating vector (φ2) of the transfer diffraction element (330) may be the angle formed by the grating vector (φ2) of the transfer diffraction element (330) with the first direction.

[0122] The output diffraction element (340) may include a plurality of third protrusions (341). The grating period (λ3) of the output diffraction element (340) may be the shortest distance between one side of the third protrusion (341) and one side of the adjacent third protrusion (341). Additionally, the grating period (λ3) of the output diffraction element (340) may be the shortest distance between the same sides of adjacent third protrusions (341). The grating vector (φ3) of the output diffraction element (340) may be the direction of separation of the adjacent third protrusions (341) of the output diffraction element (340). The magnitude of the grating vector (φ3) of the output diffraction element (340) may be the angle formed by the grating vector (φ3) of the output diffraction element (340) with the first direction.

[0123] The diffraction efficiency and uniformity of optical output according to the wavelength of light may vary depending on the grating pattern of the input diffraction element, the transfer diffraction element, and the output diffraction element. However, if the input diffraction element, the transfer diffraction element, and the output diffraction element each have a single grating pattern, the diffraction efficiency and uniformity of optical output according to the wavelength of light may be poor compared to the case where they have multiple grating patterns. However, since this may vary depending on the structure of the multiple grating patterns and the position of the diffraction elements, the present invention proposes how to set the grating pattern structure of the input diffraction element, the transfer diffraction element, and the output diffraction element divided into multiple regions, and how to arrange the positions of the diffraction elements.

[0124] FIG. 5a is a diagram showing the arrangement of a diffraction element included in a light guide device according to a first embodiment of the present invention, and FIG. 5b and FIG. 5c are diagrams showing the NA space of light passing through a diffraction element including a plurality of regions exemplified in FIG. 5a.

[0125] Referring to FIG. 5a, the light guide device (500) may include an input diffraction element (510), a transfer diffraction element (520), and an output diffraction element (530). The input diffraction element (510), the transfer diffraction element (520), and the output diffraction element (530) may each be composed of one.

[0126] According to the first embodiment, the input diffraction element (510) may include a plurality of regions. For example, the input diffraction element (510) may include a first region and a second region. The first region and the second region may be regions distinguished by a grating pattern. The first region may have a first grating pattern, and the second region may have a second grating pattern. In the present invention, variables for distinguishing grating patterns include period (or grating period) and azimuth (or grating vector), and if any one of the variables representing the grating pattern is different from each other, the two grating patterns may not be the same grating pattern. In the first embodiment, the first grating pattern and the second grating pattern may be different. Specifically, the period of the first grating pattern and the period of the second grating pattern may be different from each other. There are no restrictions on the setting of the period of the first grating pattern and the period of the second grating pattern, but they must be set so that light of wavelengths corresponding to RGB can propagate. In order for light of wavelengths corresponding to RGB to be set to propagate, the period of the first grating pattern and the period of the second grating pattern must satisfy the following [Equation 1].

[0127] [Mathematical Formula 1]

[0128] Center wavelength of Blue / Period of the first grating pattern of the input diffraction element = Center wavelength of Red / Period of the second grating pattern of the input diffraction element

[0129] The azimuth of the first grating pattern and the azimuth of the second grating pattern may be the same. For example, the periods of the first grating pattern and the second grating pattern may be 303 nm and 414 nm, and the azimuth may be -75 degrees. The arrangement of the first region and the second region in the input diffraction element (510) is described in FIGS. 8a to 8c and is omitted here.

[0130] The transfer diffraction element (520) may also include a plurality of regions, similar to the input diffraction element (510). For example, the transfer diffraction element (520) may include a third region and a fourth region. The third region and the fourth region may also be regions distinguished by a grating pattern. Accordingly, the third region may have a third grating pattern, and the fourth region may have a fourth grating pattern. For reference, the third and fourth may be used to distinguish them from the first and second of the input diffraction element. In the first embodiment, the third grating pattern and the fourth grating pattern may have different periods but the same azimuth angle. For example, the periods of the third grating pattern and the fourth grating pattern may be 224.2 nm and 306.4 nm, respectively, and the azimuth angle may be 57.46 degrees. The arrangement of the third region and the fourth region in the transfer diffraction element (520) is described in FIGS. 9a and 9b and is omitted here.

[0131] According to one embodiment, light incident on a first region of an input diffraction element (510) can be transmitted to a third region of a transfer diffraction element (520), and light incident on a second region of an input diffraction element (510) can be transmitted to a fourth region of a transfer diffraction element (520).

[0132] Referring to FIG. 5a, the output diffraction element (530) may be positioned on one side of the input diffraction element (510) and the transfer diffraction element (520) and may include a plurality of regions. For example, the output diffraction element (530) may include a fifth region and a sixth region. The fifth region and the sixth region may each have a grating pattern, and in the first embodiment, the fifth grating pattern and the sixth grating pattern may be grating patterns that differ only in their period. For example, the period of the fifth grating pattern and the sixth grating pattern may be 303 nm and 414 nm, and the azimuth may be -170 degrees. The arrangement of the fifth region and the sixth region in the output diffraction element (530) is described in FIG. 9a and FIG. 9b and is therefore omitted here.

[0133] According to one embodiment, light incident on the third region of the transfer diffraction element (520) can be transmitted to the fifth region of the output diffraction element (530), and light incident on the fourth region of the transfer diffraction element (520) can be transmitted to the sixth region of the output diffraction element (530). However, if light incident on the third region of the transfer diffraction element (520) is transmitted to the sixth region of the output diffraction element (630), or light incident on the fourth region of the transfer diffraction element (520) is transmitted to the fifth region of the output diffraction element (530), a ghost image may occur.

[0134] FIG. 5b shows the NA space of light incident through the first region of the input diffraction element, exemplified by FIG. 5a, passing through the third region of the transfer diffraction element, and exiting through the fifth region of the output diffraction element. FIG. 5c shows the NA space of light incident through the second region of the input diffraction element, exemplified by FIG. 5a, passing through the fourth region of the transfer diffraction element, and exiting through the sixth region of the output diffraction element. FIG. 5b and FIG. 5c are arranged so that the NA of the center wavelength of the light transferred by the input diffraction element, that is, the center wavelength of RGB, is located at the center of the circle. Referring to FIG. 5b and FIG. 5c, the result of [Equation 1] is 1.5, indicating that the period of the first grating pattern and the period of the second grating pattern are set so that light of all wavelengths corresponding to RGB is propagated.

[0135] FIG. 6 is a diagram showing the arrangement of diffraction elements included in a light guide device according to a second embodiment of the present invention.

[0136] Referring to FIG. 6, the light guide device (600) may include an input diffraction element (610), a transfer diffraction element (620-1, 620-2), and an output diffraction element (630). The input diffraction element (610) and the output diffraction element (630) may be physically configured as one, and the transfer diffraction elements (620-1, 620-2) may be physically configured separately.

[0137] According to the second embodiment, the input diffraction element (610) may include a plurality of regions. For example, the input diffraction element (610) may include a first region and a second region. The first region and the second region may be regions distinguished by a grating pattern. The first region may have a first grating pattern, and the second region may have a second grating pattern. In the present invention, variables for distinguishing grating patterns include period and azimuth angle, and if either of the variables representing the two grating patterns is different from each other, the two grating patterns may not be the same grating pattern. In the second embodiment, the first grating pattern and the second grating pattern may be different. Specifically, the period of the first grating pattern may be different from the period of the second grating pattern. There are no restrictions on the setting of the period of the first grating pattern and the period of the second grating pattern, but they must be set so that light of wavelengths corresponding to RGB can propagate. In order for light of wavelengths corresponding to RGB to be propagated, the period of the first grating pattern and the period of the second grating pattern must satisfy [Equation 1] as described in FIG. 5a above. Additionally, the azimuth angle of the first grating pattern may differ from the azimuth angle of the second grating pattern. For example, the periods of the first grating pattern and the second grating pattern may be 303 nm and 414 nm, and the azimuth angles may be -55 degrees and 55 degrees. The arrangement of the first region and the second region in the input diffraction element (610) is described in FIG. 8a to FIG. 8c and is therefore omitted here.

[0138] The transfer diffraction element (620-1, 620-2) may also include a plurality of regions. The input diffraction element (610) is a diffraction element in which a plurality of regions are physically composed as one, but the transfer diffraction element (620-1, 620-2) may be a diffraction element in which a plurality of regions are physically separated. For example, the transfer diffraction element may include a third region (620-1) and a fourth region (620-2), and the third region (620-1) and the fourth region (620-2) may be physically separated regions. In the second embodiment, the third region (620-1) may have a third grating pattern, and the fourth region (620-2) may have a fourth grating pattern. Here, the third grating pattern and the fourth grating pattern may be different from each other. Specifically, the period and azimuth of the third grating pattern may be different from the period and azimuth of the fourth grating pattern. For example, the periods of the third and fourth lattice patterns may be 224.2 nm and 280.7 nm, and the azimuths may be 77.5 degrees and -82.5 degrees.

[0139] According to one embodiment, light incident on a first region of an input diffraction element (610) can be transmitted to a third region (620-1) of a transfer diffraction element, and light incident on a second region of an input diffraction element (610) can be transmitted to a fourth region (620-2) of a transfer diffraction element.

[0140] Referring again to FIG. 6, the output diffraction element (630) may be positioned between multiple regions of physically separated transfer diffraction elements. Specifically, the output diffraction element (630) may be positioned between a third region (620-1) and a fourth region (620-2).

[0141] According to one embodiment, the output diffraction element (630) may also include a plurality of regions. For example, the output diffraction element (630) may include a fifth region and a sixth region. Although the output diffraction element (630) includes a plurality of regions, it may be a diffraction element physically composed as a single unit, similar to the input diffraction element (610). According to one embodiment, the fifth region of the output diffraction element (630) may have a fifth grating pattern, and the sixth region of the output diffraction element (630) may have a sixth grating pattern. The fifth grating pattern and the sixth grating pattern may be different from each other. Specifically, the period and azimuth of the fifth grating pattern may be different from the period and azimuth of the sixth grating pattern. For example, the period of the fifth grating pattern and the sixth grating pattern may be 303 nm and 414 nm, and the azimuth of the fifth grating pattern may be -150 degrees and 140 degrees. The arrangement of the fifth and sixth regions in the output diffraction element (630) is described in FIG. 9a and FIG. 9b and is omitted here.

[0142] According to one embodiment, light incident on the third region (620-1) of the transfer diffraction element can be transmitted to the fifth region of the output diffraction element (630), and light incident on the fourth region (620-2) of the transfer diffraction element can be transmitted to the sixth region of the output diffraction element (630). As in the second embodiment, if the regions of the transfer diffraction element are physically separated and the output diffraction element (630) is placed between them, light incident on the third region (620-1) of the transfer diffraction element may not be transmitted to the sixth region of the output diffraction element, or light incident on the fourth region (620-2) of the transfer diffraction element may not be transmitted to the fifth region of the output diffraction element. This prevents the generation of a ghost image.

[0143] FIG. 7 is a diagram showing the arrangement of diffraction elements included in a light guide device according to a third embodiment of the present invention.

[0144] Referring to FIG. 7, the light guide device (700) may include an input diffraction element (710), a transfer diffraction element (720-1, 720-2), and an output diffraction element (730). The input diffraction element (710) and the output diffraction element (730) may be physically configured as one, and the transfer diffraction elements (720-1, 720-2) may be physically configured as separate.

[0145] Similar to FIGS. 5a and FIG. 6, in the third embodiment, the input diffraction element (710) may include a plurality of regions. For example, the input diffraction element (710) may include a first region and a second region. The first region and the second region may be regions distinguished by a grating pattern. That is, if the grating patterns are the same, they may be referred to as the same region even if they are physically separated. The first region may have a first grating pattern, and the second region may have a second grating pattern. In the present invention, variables for distinguishing grating patterns include period and azimuth, and if either of the variables representing the two grating patterns is different from each other, the two grating patterns may not be the same grating pattern. In the third embodiment, the first grating pattern and the second grating pattern may also be different. Specifically, the period and azimuth of the first grating pattern may be different from the period and azimuth of the second grating pattern. According to one embodiment, there are no restrictions on the setting of the period of the first grating pattern and the period of the second grating pattern, but they must be set so that light of wavelengths corresponding to RGB can propagate. There are no restrictions on the setting of the period of the first grating pattern and the period of the second grating pattern, but they must be set so that light of wavelengths corresponding to RGB can propagate. For example, the periods of the first grating pattern and the second grating pattern may be 303 nm and 414 nm, and the azimuth angles may be -120 degrees and -55 degrees. The arrangement of the first region and the second region in the input diffraction element (710) is described in FIGS. 8a to 8c and is omitted here.

[0146] The transfer diffraction element (720-1, 720-2) may also include a plurality of regions. The input diffraction element (710) may be a diffraction element in which a plurality of regions are physically composed as one, or the transfer diffraction element (720-1, 720-2) may be a diffraction element in which a plurality of regions are physically separated. For example, the transfer diffraction element may include a third region (720-1) and a fourth region (720-2), and the third region (720-1) and the fourth region (720-2) may be physically separated regions. According to one embodiment, the third region (720-1) may have a third grating pattern, and the fourth region (720-2) may have a fourth grating pattern. In the third embodiment, the third grating pattern and the fourth grating pattern may be different from each other. Specifically, the period and azimuth of the third grating pattern may be different from the period and azimuth of the fourth grating pattern. For example, the periods of the third and fourth lattice patterns may be 183.6 nm and 362.2 nm, and the azimuths may be 37.6 degrees and 62.46 degrees.

[0147] According to one embodiment, light incident on a first region of an input diffraction element (710) can be transmitted to a third region (720-1) of a transfer diffraction element, and light incident on a second region of an input diffraction element (710) can be transmitted to a fourth region (720-2) of a transfer diffraction element.

[0148] Referring again to FIG. 7, the output diffraction element (730) may be placed on one side of a physically separated transfer diffraction element. Specifically, the output diffraction element (730) may be placed on one side of the third region (720-1) and the fourth region (720-2).

[0149] In the third embodiment, the output diffraction element (730) may be composed of a single region. Alternatively, the output diffraction element (730) may include a plurality of regions. However, the output diffraction element (730) may be composed of a single grating pattern. That is, even if the output diffraction element (730) includes a plurality of regions, each of the plurality of regions may have the same grating pattern. According to one embodiment, light incident on the third region (720-1) of the transfer diffraction element may be transmitted to the output diffraction element (730), and light incident on the fourth region (720-2) of the transfer diffraction element may also be transmitted to the output diffraction element (730). Accordingly, the period and azimuth angle of the grating patterns of the first and second regions of the input diffraction element and the third region (720-1) and fourth region (720-2) of the transfer diffraction element can be adjusted so that light transmitted from the third region (720-1) and the fourth region (720-2) of the transfer diffraction element is transmitted at the same angle. That is, the azimuth angle can be adjusted so that the grating patterns of the third region (720-1) and the fourth region (720-2) of the transfer diffraction element do not overlap. For example, the period of the fifth grating pattern and the sixth grating pattern can be 370 nm, and the azimuth angle can be -170 degrees. Through this, the output diffraction element (730) can remove ghost images using only one type of grating pattern.

[0150] FIGS. 8a to 8c are drawings showing various examples of an input diffraction element including a plurality of regions according to an embodiment of the present invention.

[0151] Referring to FIGS. 8a through 8c, the input diffraction element (800) may have a circular shape. As previously described, the input diffraction element (800) may include a plurality of regions. Each of the plurality of regions may be a region distinguished based on a grating pattern. The plurality of regions may be physically divided into sub-regions, but sub-regions belonging to the same region may have the same grating pattern. In FIGS. 8a through 8c, the plurality of regions is two regions, and FIGS. 8a and 8b show examples where it is physically divided into two regions. FIGS. 8c shows an example where it is divided into two regions based on a grating pattern but physically divided into more regions. Specifically, each region may be divided arbitrarily. For example, as in FIGS. 8a and 8b, the input diffraction element (800) may be divided in half, with one half being the first region (810) and the other being the second region (820). Alternatively, the input diffraction element (800) can be divided into a horizontal length of n and a vertical length of m, and the first region (810) and the second region (820) can be arranged alternately.

[0152] FIGS. 9a and 9b are drawings illustrating various examples of a transfer diffraction element or an output diffraction element including a plurality of regions according to an embodiment of the present invention.

[0153] Referring to FIGS. 9a and 9b, the transfer diffraction element or / and the output diffraction element (900) may have a rectangular shape. As previously described, the transfer diffraction element or / and the output diffraction element (900) may include a plurality of regions. Similar to the input diffraction element, each of the plurality of regions may be a region distinguished based on a grating pattern. The plurality of regions may be physically divided into sub-regions, but sub-regions belonging to the same region may have the same grating pattern. However, the minimum size of the sub-region must be smaller than the size of the eyebox. In FIGS. 9a and 9b as well, the plurality of regions may consist of two regions, or each of the plurality of regions may include a plurality of sub-regions. Referring to FIG. 9a and FIG. 9b, the transfer diffraction element or / and output diffraction element (900) may have a sub-region included in the first region (910) and a sub-region included in the second region (920) arranged in an alternating manner, and the shape of each region may be square or triangular, but is not limited thereto.

[0154] FIG. 10a is a diagram showing the path of light from a plurality of diffraction elements included in an optical guide device, and FIG. 10b is a diagram showing this in NA space.

[0155] Referring to FIG. 10a, the light guide device (1000) may include an input diffraction element (1010), a transfer diffraction element (1020), and an output diffraction element (1030). In the light guide device (1000), the path of light is such that light entering from the outside first enters the input diffraction element (1010), then passes through the transfer diffraction element (1020), and is emitted from the output diffraction element (1030). More specifically, light incident on the input diffraction element (1010) may be diffracted and then emitted from the transfer diffraction element (1020). Light emitted from the input diffraction element (1010) may enter the transfer diffraction element (1020), be diffracted, and then be emitted from the output diffraction element (1030). Finally, light emitted from the transfer diffraction element (1020) can be incident on the output diffraction element (1030), diffracted, and then emitted outside the light guide device (1000). The path of such light is shown in the NA space as in FIG. 10b. First, in FIG. 10b, the center wavelength of the light incident on the input diffraction element (1010) is positioned at the center (1070) of the circle in the NA space. The light incident on the input diffraction element (1010) can be diffracted by the input diffraction element (1010) and move to a first position (1080). The first position (1080) may be the position of the light emitted from the input diffraction element (1010) and incident on the transfer diffraction element (1020). The first position (1080) may be determined by the grating pattern of the input diffraction element (1010). For example, the first position (1080) may vary based on the period, azimuth, and height of the grating pattern. Light incident on the transfer diffraction element (1020) may be diffracted by the transfer diffraction element (1020) and moved to the second position (1090). The second position (1090) may be the position of light emitted from the transfer diffraction element (1020) and incident on the output diffraction element (1030). Likewise, the second position (1090) may be determined by the grating pattern of the transfer diffraction element (1020).The second position (1090) may vary based on the period, azimuth, and height of the grid pattern. Finally, light incident on the output diffraction element (1030) can be diffracted by the output diffraction element (1030) and moved back to the center of the circle (1070). That is, light corresponding to the center of the circle (1070) can be emitted from the output diffraction element (1030).

[0156] The above represents the most ideal path of light in the light guide device (1000), but not all light is transmitted along such a path, and some of it may deviate from the path and not be transmitted to the eye box. Additionally, the amount of light that deviates from the path may vary depending on the wavelength of the transmitted light. Referring again to FIG. 10a, some of the light incident on the input diffraction element (1010) may be diffracted and emitted to a place other than the transmission diffraction element (1020) (1040). Also, some of the light incident on the transmission diffraction element (1020) may also be emitted to a place other than the output diffraction element (1030) (1050). Finally, some of the light incident on the output diffraction element (1030) may also be emitted to a place other than the outside of the light guide device (1000) (1060). As light is transmitted in such an undesirable direction, the diffraction efficiency and / or uniformity of the light may be poor.

[0157] In the following, a redirecting diffraction element added to a light guide device to diffract light that is transmitted in an undesirable direction, that is, escapes, according to various embodiments of the present invention, is described.

[0158] FIG. 11a is a diagram showing the path of light in a diffraction element included in a light guide device according to the first embodiment of the present invention.

[0159] Referring to FIG. 11a, the light guide device (1100) may include an input diffraction element (1110), a transfer diffraction element (1120), and an output diffraction element (1130). The light guide device (1100) may further include a redirecting diffraction element (1140) compared to FIG. 10a. The path through which light incident within the light guide device (1100) is transmitted in the order of the input diffraction element (1110), the transfer diffraction element (1120), and the output diffraction element (1130) is the same as described in FIG. 10a and is therefore omitted here. The redirecting diffraction element (1140) may be a diffraction element for directing light that is not incident on the transfer diffraction element (1120) among the light emitted from the input diffraction element (1110). According to one embodiment, the redirecting diffraction element (1140) may be positioned in a direction opposite to the direction in which the transfer diffraction element is positioned relative to the input diffraction element (1110). The redirecting diffraction element (1140) may irradiate light that is not incident on the transfer diffraction element (1120) among the light emitted from the input diffraction element (1110), diffract it in the direction in which the input diffraction element (1110) or the transfer diffraction element (1120) is located, and then emit it. The redirecting diffraction element (1140) may also have a grating pattern like the input diffraction element (1110), the transfer diffraction element (1120), and the output diffraction element (1130). The shape of the grating pattern of the redirecting diffraction element (1140) may be one of slant, binary, and trapezoid, but is not limited thereto. The period of the grating pattern of the redirecting diffraction element (1140) may be half the period of the grating pattern of the input diffraction element (1110). The redirecting diffraction element (1140) may be metal-coated. The shape of the redirecting diffraction element (1140) may be one of a rectangle, a triangle, a trapezoid, and a parallelogram, but is not limited thereto.

[0160] FIG. 11b is a side view of the path of light that is not incident on the transfer diffraction element among the light emitted from the input diffraction element in a light guide device according to the first embodiment of the present invention.

[0161] When viewed from the side, an input diffraction element (1110), a redirecting diffraction element (1140), and a transfer diffraction element (not shown) may be disposed on a substrate (1105). With respect to the input diffraction element (1110), a redirecting diffraction element (1140) may be disposed on one side and a transfer diffraction element (not shown) may be disposed on the other side.

[0162] Referring to FIG. 11b, light (1150-1) incident on the input diffraction element (1110) can be emitted directly in the direction where the transfer diffraction element (not shown) is placed by the input diffraction element (1110) (not shown), but due to the characteristics of the light, some of it can be emitted in the direction where the redirecting diffraction element (1140) is placed (1150-2). Light (1150-3) incident on the redirecting diffraction element (1140) can be diffracted by the redirecting diffraction element (1140) and emitted again in the direction where the input diffraction element (1110) is placed (1150-4). Light emitted from the redirecting diffraction element (1140) can be incident again on the input diffraction element (1110) (1150-5). The light incident on the input diffraction element (1110) can be emitted in the direction where the transfer diffraction element (not shown) is positioned (1150-6). The light that escapes from the input diffraction element (1110) can be transferred back to the transfer diffraction element (not shown) by the redirecting diffraction element (1140), thereby increasing the efficiency of the light.

[0163] FIG. 11c is a diagram showing the path of light in the NA space in a light guide device according to the first embodiment of the present invention.

[0164] Similar to Fig. 10b, Fig. 11c also arranges the center wavelength of the light incident on the input diffraction element to be located at the center of the circle (1160) of the NA space. The light that escapes from the light incident on the input diffraction element may be incident on the redirecting diffraction element (1140). When the light incident on the redirecting diffraction element is displayed in the NA space, it is located at the first position (1170). Subsequently, the light emitted by the redirecting diffraction element and incident on the transfer diffraction element is located at the second position (1180) in the NA space. The light incident on the transfer diffraction element is diffracted and incident on the output diffraction element, which is located at the third position (1190) in the space. Subsequently, the light emitted from the output diffraction element can be seen as being located at the center of the circle (1160) in the space.

[0165] FIGS. 12a and FIGS. 12b are drawings showing examples of various shapes of a redirecting diffraction element included in a light guide device according to the first embodiment of the present invention.

[0166] Referring to FIG. 12a and FIG. 12b, the light guide device (1200) may include an input diffraction element (1210), a transfer diffraction element (1220), an output diffraction element (1230), and a redirecting diffraction element (1240, 1250). The redirecting diffraction element may be a diffraction element for incident light that is diffracted in a different direction from the input diffraction element (1210) without being diffracted in the direction in which the transfer diffraction element (1220) is positioned. For example, the redirecting diffraction element may be positioned in a direction opposite to the transfer diffraction element (1220) with respect to the input diffraction element (1210) so as to incident light that is diffracted in a direction opposite to the transfer diffraction element (1220) from the input diffraction element (1210). To this end, a redirecting diffraction element may be placed in the path of light transmitted from the input diffraction element (1210) in a direction opposite to the direction in which the transmission diffraction element (1220) is placed.

[0167] While increasing the size of a redirecting diffraction element allows for more incident light and thus improves efficiency, there may be various constraints such as the miniaturization of the light guide device, manufacturing processes, and costs.

[0168] In addition, the shape of the redirecting diffraction element may vary. For example, the shape of the redirecting diffraction element may be one of a rectangle, a triangle, a trapezoid, or a parallelogram. Most preferably, a trapezoid, which is a shape that extends widely relative to the input diffraction element, may be the most efficient shape. Furthermore, among the trapezoids, the side closer to the input diffraction element may have a shape that corresponds to or surrounds the input diffraction element.

[0169] For example, in FIG. 12a and FIG. 12b, the shape of the redirecting diffraction element may be trapezoidal. Specifically, in FIG. 12a, the redirecting diffraction element (1240) has a trapezoidal shape that is long in the direction perpendicular to the transfer diffraction element (1220) with respect to the input diffraction element (1210), and in FIG. 12b, the redirecting diffraction element (1250) may have a trapezoidal shape that is long in the direction opposite to the transfer diffraction element (1220) with respect to the input diffraction element (1210). According to one embodiment, in the trapezoidal shape of the redirecting diffraction element, the side that contacts the input diffraction element (1210) may be a shape that corresponds to the input diffraction element (1210) or surrounds the input diffraction element (1210).

[0170] FIG. 13a is a diagram showing the path of light in a diffraction element included in a light guide device according to a second embodiment of the present invention.

[0171] The first embodiment according to the present invention includes a diffraction element for switching the direction of light emitted to a location other than the transfer diffraction element, whereby light diffracted from an input diffraction element is switched, whereas the second embodiment according to the present invention relates to a light guide device including a diffraction element for switching the direction of light emitted to a location other than the output diffraction element, whereby light diffracted from a transfer diffraction element is switched. Specifically, the light guide device according to the second embodiment may include at least one of a first redirecting diffraction element and a second redirecting diffraction element as a redirecting diffraction element.

[0172] Referring to FIG. 13a, the light guide device (1300) may include an input diffraction element (1310), a transfer diffraction element (1320), and an output diffraction element (1330), and at least one of a first redirecting diffraction element (1340) and a second redirecting diffraction element (1350). Light incident on the input diffraction element (1310) may be diffracted and emitted through the transfer diffraction element (1320). Light incident on the transfer diffraction element (1320) may be diffracted and emitted through the output diffraction element (1330). However, some of the light may not be emitted through the output diffraction element (1330) but may be diffracted in a different direction and then emitted (1370-1). The first redirecting diffraction element (1340) may be a diffraction element for directing light that is diffracted in the opposite direction to the direction in which the input diffraction element (1310) is positioned, rather than being diffracted in the direction in which the output diffraction element (1330) is positioned at the transmission diffraction element (1320). The light that is diffracted by being incident on the first redirecting diffraction element (1340) may be diffracted again in the direction in which the transmission diffraction element (1320) is positioned and then emitted (1370-3).

[0173] The second redirecting diffraction element (1350) may be a diffraction element for directing light that is diffracted in the opposite direction to the direction in which the output diffraction element (1330) is positioned, rather than being diffracted in the direction in which the output diffraction element (1330) is positioned, when light incident on the transmission diffraction element (1320) is not diffracted in the transmission diffraction element (1320). The light incident on the second redirecting diffraction element (1350) and diffracted may be diffracted in the direction in which the transmission diffraction element (1320) is positioned and then emitted (1370-4). According to one embodiment, the light incident on the second redirecting diffraction element (1350) may be light (1370-2) diffracted from light emitted from the input diffraction element (1310) and incident on the transfer diffraction element (1320), or light (1370-4) diffracted from light emitted from the first redirecting diffraction element (1340) and incident on the transfer diffraction element (1320). Likewise, the light incident on the first redirecting diffraction element (1340) may be light diffracted from light emitted from the input diffraction element (1310) and incident on the transfer diffraction element (1320), or light diffracted from light emitted from the second redirecting diffraction element (1350) and incident on the transfer diffraction element (1320).

[0174] The first redirecting diffraction element (1340) and the second redirecting diffraction element (1350) may also have a grating pattern, similar to the input diffraction element (1310), the transfer diffraction element (1320), and the output diffraction element (1330). The shape of the grating pattern of the first redirecting diffraction element (1340) and the second redirecting diffraction element (1350) may be one of slant, binary, and trapezoid, but is not limited thereto. The period of the grating pattern of the first redirecting diffraction element (1340) may be half the period of the grating pattern of the input diffraction element (1310). The period of the grating pattern of the second redirecting diffraction element (1350) may be half the period of the grating pattern of the output diffraction element (1330). The first redirecting diffraction element (1340) and the second redirecting diffraction element (1350) may be coated with metal. The shape of the first redirecting diffraction element (1340) and the second redirecting diffraction element (1350) may be one of a rectangle, a triangle, a trapezoid, and a parallelogram, but is not limited thereto. Preferably, a shape that extends widely along one side of the transfer diffraction element (1320) may be the most efficient shape.

[0175] FIG. 13b is a diagram showing, as an example, the path of light in NA space in a light guide device according to a second embodiment of the present invention.

[0176] Specifically, FIG. 13b shows the central wavelength of light incident on the input diffraction element (1310) positioned at the center (1380) of the circle in NA space. Light emitted from the input diffraction element (1310) can be incident on the transfer diffraction element (1320). Light incident on the transfer diffraction element (1320) can be located at a first position (1382) in NA space. Some of the light diffracted from the transfer diffraction element (1320) can be incident on the first redirecting diffraction element (1340) rather than the output diffraction element (1330). Light incident on the first redirecting diffraction element (1340) can be located at a second position (1384) in NA space. Light diffracted from the first redirecting diffraction element (1340) can be incident on the transfer diffraction element (1320). Some of the light incident on the transfer diffraction element (1320) can be diffracted and incident on the second redirecting diffraction element (1350). Light incident on the second redirecting diffraction element (1350) can be located at a third position (1386) in NA space. Light diffracted from the second redirecting diffraction element (1350) can be incident on the transfer diffraction element (1320). Light incident on the transfer diffraction element (1320) can be incident on the output diffraction element (1330). Light incident on the output diffraction element (1330) can be located at a fourth position (1388) in NA space. Afterwards, light incident on the output diffraction element (1330) can be diffracted and emitted to the outside of the light guide device.

[0177] FIGS. 14a to 14d are drawings showing examples of various shapes of a first redirecting diffraction element and a second redirecting diffraction element included in a light guide device according to a second embodiment of the present invention.

[0178] As described in FIG. 13a, the light guide device (1400) according to the second embodiment may include a first redirecting diffraction element (1440, 1450) and / or a second redirecting diffraction element (1470, 1480) as a redirecting diffraction element. FIG. 14a and FIG. 14b show examples of the shape of the first redirecting diffraction element (1440, 1450) included in the light guide device (1400) according to the second embodiment of the present invention, and FIG. 14c and FIG. 14d show examples of the shape of the second redirecting diffraction element (1470, 1480) included in the light guide device (1400) according to the second embodiment of the present invention.

[0179] Referring to FIG. 14a and FIG. 14b, the first redirecting diffraction element (1440, 1450) may be located in the opposite direction to the input diffraction element (1410) with respect to the transfer diffraction element (1420). The first redirecting diffraction element (1440, 1450) may receive light emitted from the transfer diffraction element (1420) and emitted in the first direction (1460) without being transferred to the output diffraction element (1430).

[0180] The larger the size of the first redirecting diffraction element (1440, 1450), the more light can be incident and thus the higher the efficiency can be, but the size may be limited due to various constraints such as miniaturization of the light guide device, manufacturing process, and cost.

[0181] The shape of the first redirecting diffraction element (1440, 1450) may vary. For example, the shape of the first redirecting diffraction element (1440, 1450) may be one of a rectangle, a triangle, a trapezoid, and a parallelogram. Most preferably, a trapezoid, which is a shape that extends widely relative to the transfer diffraction element (1420), may be the most efficient shape. For example, a trapezoid shape that extends from one side of the transfer diffraction element (1420) furthest from the input diffraction element (1410) may be the most efficient shape.

[0182] For example, in FIG. 14a and FIG. 14b, the shape of the first redirecting diffraction element (1440, 1450) may be trapezoidal. Specifically, in FIG. 14a, the first redirecting diffraction element (1440) may have a trapezoidal shape that is long in the second direction (1465), and in FIG. 14b, the first redirecting diffraction element (1450) may have a trapezoidal shape that is long in the first direction (1460).

[0183] Referring to FIG. 14c and FIG. 14d, the second redirecting diffraction element (1470, 1480) may be positioned opposite to the output diffraction element (1430) with respect to the transfer diffraction element (1420). The second redirecting diffraction element (1470, 1480) may be incident on light that is emitted from the transfer diffraction element (1420) and is not transmitted to the output diffraction element (1430) but is emitted in a third direction (1490).

[0184] The larger the size of the second redirecting diffraction element (1470, 1480), the more light can be incident and thus the higher the efficiency can be, but the size may be limited due to various constraints such as miniaturization of the light guide device, manufacturing process, and cost.

[0185] The shape of the second redirecting diffraction element (1470, 1480) may also vary. For example, the shape of the second redirecting diffraction element (1470, 1480) may be one of a rectangle, a triangle, a trapezoid, and a parallelogram. Most preferably, a trapezoid, which is a shape that extends widely relative to the transfer diffraction element (1420), may be the most efficient shape. For example, a trapezoid shape that extends from one side of the transfer diffraction element (1420) furthest from the output diffraction element (1430) may be the most efficient shape.

[0186] For example, in FIG. 14c and FIG. 14d, the shape of the second redirecting diffraction element (1470, 1480) may be trapezoidal. Specifically, in FIG. 14c, the second redirecting diffraction element (1470) may have a trapezoidal shape that is long in the fourth direction (1495), and in FIG. 14d, the second redirecting diffraction element (1480) may have a trapezoidal shape that is long in the third direction (1490).

[0187] Although the first and second embodiments have been described separately, according to one embodiment, the light guide device may include all the redirecting diffraction elements included in the first and second embodiments.

[0188] FIG. 15a is a diagram showing the path of light in a diffraction element included in a light guide device according to a third embodiment of the present invention, and FIG. 15b is a diagram showing this in NA space.

[0189] A third embodiment relates to a light guide device comprising an input diffraction element and an output diffraction element without a transfer diffraction element. The light guide device according to the third embodiment may also further include a redirecting diffraction element. Referring to FIG. 15a, the light guide device (1500) may include an input diffraction element (1510), an output diffraction element (1530), and a redirecting diffraction element (1540). Light incident on the input diffraction element (1510) may be diffracted and incident on the output diffraction element (1530), but due to the characteristics of light, some of the light incident on the input diffraction element (1510) may be diffracted in a different direction. Light diffracted in a different direction from the input diffraction element (1510) may be incident on the redirecting diffraction element (1540) (1550-1). Light incident on the redirecting diffraction element (1540) can be diffracted from the redirecting diffraction element (1540) again in the direction where the input diffraction element (1510) is located and emitted (1550-2). The light emitted from the redirecting diffraction element (1540) can finally be incident on the output diffraction element (1530), diffracted, and emitted to the outside. When such a light path is represented on the NA space, it is as shown in FIG. 15b. First, FIG. 15b shows the central wavelength of the light incident on the input diffraction element (1510) positioned at the center (1560) of the circle in the NA space. The light that escapes from the light incident on the input diffraction element (1510) can be incident on the redirecting diffraction element (1540). At this time, when the light incident on the redirecting diffraction element (1540) is displayed in the NA space, it is located at the first position (1570). Subsequently, the light emitted from the redirecting diffraction element (1540) can pass through the second position (1580) and the third position (1590) and be emitted to the outside of the light guide device. A detailed description is similar to that of the first and second embodiments and is therefore omitted here.

[0190] According to one embodiment, the redirecting diffraction element (1540) may have a grating pattern similar to the input diffraction element (1510) and the output diffraction element (1530). The shape of the grating pattern of the redirecting diffraction element (1540) may be one of slant, binary, and trapezoid, but is not limited thereto. The period of the grating pattern of the redirecting diffraction element (1540) may be half the period of the grating pattern of the input diffraction element (1510). The redirecting diffraction element (1540) may be metal-coated. The shape of the redirecting diffraction element (1540) may be one of a rectangle, a triangle, a trapezoid, and a parallelogram, but is likewise not limited thereto.

[0191] FIGS. 16a and FIGS. 16b are drawings showing examples of various shapes of a redirecting diffraction element included in a light guide device according to a third embodiment of the present invention.

[0192] Referring to FIGS. 16a and 16b, the light guide device (1600) may include an input diffraction element (1610), an output diffraction element (1630), and a redirecting diffraction element (1640, 1650). The redirecting diffraction element may be a diffraction element for directing light that is diffracted in a different direction from the input diffraction element (1610) without being diffracted in the direction in which the output diffraction element (1630) is positioned. For example, the redirecting diffraction element may be positioned in a direction opposite to the output diffraction element (1630) with respect to the input diffraction element (1610) to direct light that is diffracted in a direction opposite to the output diffraction element (1630) from the input diffraction element (1610). To this end, a redirecting diffraction element may be placed in a path through which light diffracted from an input diffraction element (1610) is transmitted in a direction opposite to the direction in which the output diffraction element (1630) is placed.

[0193] Although increasing the size of a redirecting diffraction element allows for more incident light and thus improves efficiency, its size may be limited due to various constraints such as the miniaturization of the light guide device, manufacturing processes, and costs.

[0194] In addition, the shape of the redirecting diffraction element may vary. For example, the shape of the redirecting diffraction element may be one of a rectangle, a triangle, a trapezoid, or a parallelogram. Most preferably, a trapezoid, which is a shape that extends widely relative to the input diffraction element, may be the most efficient shape. Furthermore, among the trapezoids, the side closer to the input diffraction element may have a shape that corresponds to or surrounds the input diffraction element.

[0195] For example, in FIG. 16a and FIG. 16b, the shape of the redirecting diffraction element may be trapezoidal. Specifically, in FIG. 16a, the redirecting diffraction element (1640) has a trapezoidal shape that is long in the direction perpendicular to the output diffraction element (1630) with respect to the input diffraction element (1610), and in FIG. 16b, the redirecting diffraction element (1650) may have a trapezoidal shape that is long in the direction opposite to the output diffraction element (1630) with respect to the input diffraction element (1610). According to one embodiment, in the trapezoidal shape of the redirecting diffraction element, the side that contacts the input diffraction element (1610) may be a shape that corresponds to the input diffraction element (1610) or surrounds the input diffraction element (1610).

[0196] According to one embodiment, the shape of the redirecting diffraction element presented in FIGS. 16a and 16b may be the same or similar to the shape of the redirecting diffraction element presented in FIGS. 12a and 12b.

[0197] Although the invention has been described above with reference to embodiments, this is merely illustrative and does not limit the invention. Those skilled in the art will understand that various modifications and applications not exemplified above are possible within the scope of the essential characteristics of the embodiments. For example, each component specifically shown in the embodiments may be modified and implemented. Furthermore, differences related to such modifications and applications should be interpreted as being included within the scope of the invention as defined in the appended claims.

Claims

1. An input diffraction element comprising a first region having a first grating pattern and a second region having a second grating pattern; A transfer diffraction element comprising a third region having a third grating pattern and a fourth region having a fourth grating pattern; and The output diffraction element includes a fifth region having a fifth grating pattern and a sixth region having a sixth grating pattern, and The period of the first grid pattern and the period of the second grid pattern are different from each other, The period of the third grid pattern and the period of the fourth grid pattern are also different from each other, A light guide device in which the period of each of the above grating patterns is set so that the wavelength of light incident on the input diffraction element is fully propagated.

2. In Paragraph 1, If the above input diffraction element is set so that all wavelengths of light incident on it are propagated, A light guide device in which the wavelength of light incident on the input diffraction element and the period of the grating pattern are both the same.

3. In Paragraph 1, A light guide device in which the period of the fifth grid pattern and the period of the sixth grid pattern are also different from each other.

4. In Paragraph 3, The azimuth angle of the first grid pattern and the azimuth angle of the second grid pattern are the same, The azimuth angle of the third grid pattern and the azimuth angle of the fourth grid pattern are the same, A light guide device in which the azimuth angle of the fifth grid pattern and the azimuth angle of the fifth grid pattern are the same.

5. In Paragraph 3, The azimuth angle of the first grid pattern and the azimuth angle of the second grid pattern are different from each other, The third region and the fourth region are physically separated and arranged, and the azimuth angle of the third grid pattern and the azimuth angle of the fourth grid pattern are different from each other, and A light guide device in which the azimuth angle of the fifth grid pattern and the azimuth angle of the sixth grid pattern are different from each other.

6. In Paragraph 5, The above output diffraction element is a light guide device disposed between the third region and the fourth region of the above transfer diffraction element.

7. In Paragraph 1, The azimuth angle of the first grid pattern and the azimuth angle of the second grid pattern are different from each other, The third region and the fourth region are physically separated and arranged, and the azimuth angle of the third grid pattern and the azimuth angle of the fourth grid pattern are different from each other, and A light guide device wherein the output diffraction element is disposed on one side of the third region and the fourth region of the transfer diffraction element, and the period and azimuth of the fifth grating pattern are the same as the period and azimuth of the sixth grating pattern.

8. In Paragraph 1, A light guide device in which the first to sixth regions are composed of a plurality of sub-regions.

9. In Paragraph 8, A light guide device in which the size of the cell in the fifth region and the size of the cell in the sixth region are smaller than the size of the eyebox.

10. Substrate; It includes an input diffraction element, a transfer diffraction element, an output transfer element, and a redirecting diffraction element disposed on the substrate, and The above input diffraction element diffracts light incident from outside the substrate and emits it to the transfer diffraction element; The above-mentioned transfer diffraction element diffracts light incident on the above-mentioned transfer diffraction element and emits it to the above-mentioned output rotating element; The output diffraction element diffracts light incident from the transfer diffraction element and emits it to the outside of the substrate; and The above-described redirecting diffraction element is a light guide device that diffracts and emits incident light emitted from the above-described input diffraction element or the above-described transfer diffraction element.

Images