KR20240026065A - Display apparatus - Google Patents

Abstract

The disclosed display device includes a display element that emits light that displays an image; a waveguide including a first surface on which the light is incident, and a second surface opposing the first surface; an input coupler provided in the waveguide to input the light into the waveguide; a telecentric assembly configured to equalize the angle of incidence of light incident on the input coupler; and an output coupler that outputs the light propagating within the waveguide to the outside.

Description

Display apparatus {Display apparatus}

An exemplary embodiment relates to a display device with improved light uniformity.

Virtual reality is a technology that allows people to experience life-like experiences in a computer-generated virtual world. Augmented reality is a technology that allows virtual images to be mixed with the physical environment or space of the real world. Near-eye displays, which are implemented as virtual reality displays or augmented reality displays, focus virtual images in space using a combination of optical and stereoscopic images. In these display devices, display resolution and image processing are important.

Optical systems based on waveguides are being researched and developed as augmented reality devices such as augmented reality glasses. Conventional waveguides input light into the waveguide using free-form reflection or multi-mirror reflection, or input light into the waveguide using an input-coupling diffractive element such as a diffractive optical element or a holographic optical element. When using free-form reflection or multi-mirror reflection, the structure can be simple and light transmission efficiency can be high, but there is a limit to the viewing angle and it is difficult to make the waveguide thinner. Additionally, image quality may deteriorate due to low uniformity of light propagating through the waveguide.

A display device according to an example embodiment includes a display element that emits light that displays an image. The waveguide includes a first surface on which the light is incident, and a second surface opposing the first surface. An input coupler is provided in the waveguide to input the light into the waveguide. The telecentric assembly is provided between the display element and the waveguide and is configured to equalize the angle of incidence of light incident on the input coupler. The output coupler outputs light propagating within the waveguide to the outside.

Figure 1 schematically shows a display device according to an exemplary embodiment.
FIG. 2 is a diagram illustrating an optical path in a display device according to an exemplary embodiment.
Figure 3 shows the diffraction efficiency of the output coupler according to the area of the waveguide of the display device according to an exemplary embodiment.
Figure 4 shows a display device according to one embodiment.
Figure 5 shows an example in which a display device according to an embodiment includes two display elements.
Figure 6 is a cross-sectional view taken along line II of Figure 5.
FIG. 7 illustrates an example of sending image light generated from one display element through two paths in a display device according to an embodiment.
FIG. 8 illustrates an example of implementing an augmented reality display device in a display device according to an embodiment.
Figure 9 schematically shows an electronic device according to an example embodiment.
FIG. 10 illustrates an example in which a user wears a display device according to an exemplary embodiment.

Hereinafter, display devices according to various embodiments will be described in detail with reference to the attached drawings. In the following drawings, the same reference numerals refer to the same components, and the size of each component in the drawings may be exaggerated for clarity and convenience of explanation. Terms such as first, second, etc. may be used to describe various components, but the components should not be limited by the terms. Terms are used only to distinguish one component from another.

Singular expressions include plural expressions unless the context clearly dictates otherwise. Additionally, when a part "includes" a certain component, this means that it may further include other components rather than excluding other components, unless specifically stated to the contrary. Additionally, the size or thickness of each component in the drawings may be exaggerated for clarity of explanation. Additionally, when a predetermined material layer is described as existing on a substrate or another layer, the material layer may exist in direct contact with the substrate or other layer, or a third layer may exist in between. In addition, since the materials forming each layer in the examples below are illustrative, other materials may be used.

In addition, terms such as “... unit” and “module” used in the specification refer to a unit that processes at least one function or operation, which may be implemented as hardware or software, or as a combination of hardware and software. .

The specific implementations described in this embodiment are examples and do not limit the technical scope in any way. For the sake of brevity of the specification, descriptions of conventional electronic components, control systems, software, and other functional aspects of the systems may be omitted. In addition, the connections or connection members of lines between components shown in the drawings exemplify functional connections and/or physical or circuit connections, and in actual devices, various functional connections or physical connections may be replaced or added. Can be represented as connections, or circuit connections.

The use of the term “above” and similar referential terms may refer to both the singular and the plural.

The steps comprising the method may be performed in any suitable order unless explicitly stated that they must be performed in the order described. In addition, the use of all exemplary terms (e.g., etc.) is simply for explaining the technical idea in detail, and unless limited by the claims, the scope of rights is not limited by these terms.

Figure 1 illustrates a display device according to an exemplary embodiment.

The display device 100 includes a display element 110 that emits light for displaying an image, a waveguide 130 that transmits light from the display element 110, and a device provided between the display element 110 and the waveguide 130. It includes a telecentric assembly 120, an input coupler 140 that inputs light into the waveguide 130, and an output coupler 150 that outputs light propagating within the waveguide 130 to the outside.

The display element 110 may include an LCD, Liquid Crystal on Silicon (LCoS), an OLED display, an LED display, or a projector. The display element 110 may process image signals to form a two-dimensional image or a three-dimensional image. Alternatively, the display element 110 may include computed generated holography (CGH) to form a holographic image.

The image output from the display element 110 may be incident on the waveguide 130 and transmitted to the user's eyes (E) through the waveguide 130. In this specification, the image includes the concept of image light displaying the image.

The telecentric assembly 120 may be configured to make the angle of incidence of light incident on the input coupler 140 the same at all positions. The telecentric assembly 120 includes a first lens 121, a second lens 122 spaced apart from the first lens 121, and a space between the first lens 121 and the second lens 122. It may include an optical filter 123. The optical filter 123 may include, for example, a pinhole structure. Light passing through the telecentric assembly 120 becomes parallel light and may be incident on the input coupler 140 at the same angle of incidence. For example, light passing through the telecentric assembly 120 may be vertically incident on the input coupler 140.

Light emitted from the display element 110 may be incident on the telecentric assembly 120 without diffusion. Generally, a display element is provided with a diffusion plate to diffuse the light emitted from the display element, but the display element 110 of this embodiment does not have a diffusion plate and allows the light emitted from the display element 110 to proceed without diffusion. Since the light emitted from the display element 110 is not spread but travels straight, the light emitted from each pixel of the display element 110 can propagate as a straight ray. A pixel may represent the basic unit for forming an image in a display device. Since the light emitted from the display element 110 travels straight without diffusion, the light passing through the telecentric assembly 120 may be incident on the input coupler 140 with a cross-sectional area equal to the area of the display element 110. The area of the display element 110 may represent an effective area used to form an image in the display element 110. In other words, the cross-sectional width of the light bundle emitted from the display element 110 may be the same as the width W1 of the display element 110. The width W1 of the display element 110 may represent the width in the horizontal direction (x-direction) of the effective area of the display element 110 or the width in the horizontal direction (x-direction) based on the direction in which the user views the image.

When a straight ray from the display element 110 is incident on the input coupler 140 through the telecentric assembly 120, the light corresponding to each pixel of the display element 110 is parallel light and is transmitted to the input coupler 140. Since the incident angle of light incident on the input coupler 140 may all be the same. Since the incident angles of the light incident on the input coupler 140 are all the same, the diffraction angle (θ) at the input coupler 140 and the number of reflections at the waveguide 130 of the lights corresponding to each pixel of the display element 110 are the same. can do. Accordingly, the image formed in the display element 110 can be copied and propagated with the same light intensity and quality across all pixels.

In the case of a general display device, a diffuser is provided in front of the display element, so the light is diffused in each pixel of the display element as the light passes through the display element after hitting the diffuser. Accordingly, because the light corresponding to each pixel is incident on the input coupler at different angles, it may propagate at different angles in the waveguide. Therefore, the intensity of light may vary depending on the location of the waveguide. To solve this problem, in an exemplary embodiment, light passes through the display element 110 without diffusion, so that the light coming from each pixel of the display element 110 does not spread but propagates in the form of a thin straight beam. In addition, the telecentric assembly 120 can further refine the light corresponding to each pixel propagating as a thin straight beam using the optical filter 123. As the light corresponding to each pixel thus refined passes through the second lens 122, it may be incident on the input coupler 140 in the form of parallel light at all positions. Since the light emitted from each pixel of the display element 110 travels creating one parallel light bundle, the angle of incidence of the light incident on the input coupler 140 is the same, and accordingly, the diffraction is diffracted by the input coupler 140. The angle (θ) can also all be the same. For example, light incident on the input coupler 140 may be incident perpendicular to the input coupler 140.

According to the above-described structure, the waveguide 130 can be configured to have a thickness t that satisfies the following equation.

t = W1 / 2 tan(θ) <Equation 1>

Here, W1 represents the width of the display element 110, and θ represents the diffraction angle of light diffracted by the input coupler 140.

Meanwhile, hereinafter, the lights corresponding to each pixel of the display element 110 will be referred to as a field.

As described above, the light from the display element 110 exits without diffusion and enters the input coupler 140 as parallel light by the telecentric assembly 120, so that the width W1 of the display element 110 is, The cross-sectional width of the light passing through the telecentric assembly 120 may be equal to the width W2 of the input coupler 140. The cross-sectional width of light may represent the x-direction width, and the width W2 of the input coupler 140 may represent an effective width in the same direction as the width W1 of the display element 110. The effective width may represent the width in the horizontal direction (x direction) of the area where light enters. The horizontal direction (x direction) may represent the horizontal direction based on which the viewer views the image.

The waveguide 130 may include a first surface 131 on which light is incident, and a second surface 132 opposing the first surface 131. The input coupler 140 may be provided on at least one of the first surface 131 and the second surface 132. Figure 1 shows an example in which the input coupler 140 is provided on the first surface 131. The input coupler 140 may include, for example, a diffractive optical element or a holographic optical element.

The output coupler 150 faces the direction selection diffusion plate 151 provided on either the first side 131 or the second side 132 of the waveguide 130. It may include a lens array 153 provided on the other side of the waveguide 130. The direction-selective diffusion plate 151 can diffuse only light entering at a specific angle and transmit light entering at other angles as is. The direction selective diffusion plate 151 may include holographic optical elements (HOEs) or volume grating (VG). Referring to FIG. 2, since part of the fields reaching the direction selective diffusion plate 151 are diffused and the remaining part is totally reflected again and propagated to the waveguide 130, the display device 100 is operated by the display element 110. At the same time as the formed image is copied, each field can have the effect of spreading. In an exemplary embodiment, since all the light diffracted in the input coupler 140 propagates at the same angle, the image light transmitted through the waveguide 130 can be replicated with the same size as the image formed in the display element 110. .

Meanwhile, in order for the image formed by the display element 110 to be displayed to the viewer, each field must spread out over a wide area and be delivered to the viewer. In an exemplary embodiment, since each field propagates in the form of a thin ray as it is emitted from the display element 110, the lens array 153 can spread each field over a wide area so that it enters the viewer's eye (E). In other words, the lens array 153 can allow each field to be propagated to the user in the form of wide parallel light. At this time, because all fields propagate at the same angle and are diffracted the same number of times, the image light can be delivered to the user with the same intensity. Therefore, users can watch images with uniform brightness.

Referring again to FIG. 1, the lens array 153 may include a plurality of lenses 152, and the plurality of lenses 152 may be provided to correspond to positions where image light generated by the display element 110 is copied. You can. For example, as the image light is transmitted through the waveguide 130, the first region (pos1), the second region (pos2), the third region (pos3), the fourth region (pos4), and the fifth region (pos5) , a duplicate image can be displayed in the sixth area (pos6). The number of duplicate images is not limited to this. Additionally, each lens 152 of the lens array 153 may be provided to correspond to a duplicate image. Accordingly, the width W3 of the lens 152 may be equal to the width W1 of the display element 110.

Meanwhile, the direction selective diffusion plate 151 may include a holographic pattern whose diffraction efficiency increases from the entrance to the exit of the waveguide 130. In other words, the direction-selective diffusion plate 151 may include a holographic pattern whose diffraction efficiency gradually increases along the direction (x-direction) in which light propagates in the waveguide 130. Figure 3 shows the diffraction efficiency of the direction selective diffusion plate 151 for each area of the waveguide 130. Referring to FIG. 3, the direction selective diffusion plate 151 has a diffraction efficiency of the first area (pos1) (e1) < diffraction efficiency of the second area (pos2) (e2) < diffraction efficiency of the third area (pos3) It may be configured to have a relationship of e4) < diffraction efficiency (e4) of the fourth region (pos4) < diffraction efficiency (e5) of the fifth region (pos5). By adjusting the diffraction efficiency of the direction selective diffusion plate 151 in this way, the light intensity can be made uniform in the direction in which light propagates in the waveguide 130.

Figure 4 shows a display device according to another embodiment.

Components using the same reference numerals as in FIG. 1 in FIG. 4 are substantially the same as those described with reference to FIG. 1 , and therefore detailed description thereof will be omitted here.

The display device 200 includes an output coupler 250 that outputs light propagating from the waveguide 130 to the outside. The output coupler 250 includes a polarization volume grating 251 provided on one of the first side 131 and the second side 132 of the waveguide 130, and a polarization modulation layer provided on the other side of the waveguide 130 ( 255) and a lens array 253. Polarization volume grating 251 can only respond to specific polarization. For example, the first polarized light may be reflected and the second polarized light may be transmitted. For example, the polarization volume grating 251 may be configured to reflect S-polarized light and transmit P-polarized light, or to reflect right-handed circularly polarized light and transmit left-handed circularly polarized light. The polarization modulation layer 255 can modulate the degree of polarization for each region. The polarization modulation layer 255 may include an anisotropic material such as liquid crystal, and the degree of polarization or the polarization modulation rate may be adjusted depending on the degree of rotation of the anisotropic material. The diffraction efficiency diffracted by the polarization volume grating 251 may vary depending on the polarization modulated in the polarization modulation layer 255. Through this, the efficiency of light diffracted by the polarization volume grating 251 can be adjusted to easily increase brightness uniformity.

By adjusting the degree of polarization of the polarization modulation layer 255, the polarization volume grating 251 has the diffraction efficiency (e1) of the first region (pos1) < diffraction efficiency (e2) of the second region (pos2) < third region ( The relationship between diffraction efficiency (e4) of pos3) < diffraction efficiency (e4) of fourth region (pos4) < diffraction efficiency (e5) of fifth region (pos5) < diffraction efficiency (e6) of sixth region (pos6) You can have it. By adjusting the diffraction efficiency of the polarization volume grating 251 in this way, the light intensity can be made uniform in the direction in which light propagates in the waveguide 130.

A lens array 253 may be provided under the polarization modulation layer 255. The lens array 253 can spread each field over a wide area so that it enters the viewer's eyes (E).

Figures 5 and 6 schematically show a display device equipped with two input couplers. FIG. 5 is a plan view of the display device, and FIG. 6 is a cross-sectional view taken along line II of FIG. 5 .

Components using the same reference numerals as in FIG. 1 in FIGS. 5 and 6 are substantially the same as those described with reference to FIG. 1 , and therefore detailed descriptions thereof are omitted here.

The display device 100A includes a first display element 111 emitting first light Ll and a second display element 112 emitting second light L2, and the first display element 111 may be arranged to make the first light L1 incident on one side of the waveguide 130, and the second display element 112 may be arranged to make the second light L2 incident on the other side of the waveguide 130. . A first input coupler 141 is provided in the waveguide 130 to correspond to the first display element 111, and a second input coupler 142 is provided in the waveguide 130 to correspond to the second display element 112. It can be. The first input coupler 141 and the second input coupler 142 may be arranged to face each other diagonally on one surface of the waveguide 130.

A first telecentric assembly 1201 is disposed between the first display element 111 and the waveguide 130, and a second telecentric assembly 1202 is disposed between the second display element 112 and the waveguide 130. can be placed. Since the configuration and operational effects of the first telecentric assembly 1201 and the second telecentric assembly 1202 are substantially the same as those described with reference to FIG. 1, detailed descriptions are omitted here.

A first optical path converter 145 may be further provided to convert the optical path of the first light L1 diffracted by the first input coupler 141 to the direction selection diffusion plate 151. In addition, a second optical path converter 146 may be further provided to convert the optical path of the second light L2 diffracted by the second input coupler 142 toward the direction selection diffusion plate 151.

In the display device 100A, the first light L1 from the first display element 111 and the second light L2 from the second display element 112 propagate symmetrically on both sides of the waveguide 130, respectively. Therefore, the decrease in diffraction efficiency along the direction of light propagation in the direction selective diffusion plate 151 can be canceled out in both directions. Therefore, even without adjusting the diffraction efficiency of the direction selective diffusion plate 151, the uniformity of the light intensity propagating along the waveguide 130 can be increased.

Figure 7 shows a display device according to another embodiment.

The display device 100B shows an embodiment in which image light emitted from one display element 110 is split into two paths and sent to the waveguide 130.

Components using the same reference numerals as those in FIGS. 1 and 6 in FIG. 7 are substantially the same as those described with reference to FIG. 1 , and therefore detailed description thereof will be omitted here.

The display device 100B may further include an optical element 160 that splits light emitted from the display element 110 into a first optical path P1 and a second optical path P2. The optical element 160 may include, for example, a polarizing beam splitter that transmits S-polarized light and reflects P-polarized light, or a beam splitter that transmits some light and reflects some light.

A telecentric assembly 120 may be provided in each of the first optical path P1 and the second optical path P2, and the telecentric assembly 120 is shown in a simplified manner for convenience. A first direction selection diffusion plate 154 and a second direction selection diffusion plate 155 may be stacked on one side of the waveguide 130. The first direction selection diffusion plate 154 diffracts the first light L1 reflected from the first input coupler 141, and the second direction selection diffusion plate 155 diffracts the first light L1 reflected from the second input coupler 142. The second light L2 may be diffracted.

The display device 100B may divide image light from one display element 110 into two optical paths and propagate symmetrically on both sides of the waveguide 130. As a result, the decrease in diffraction efficiency along the light propagation direction in the first direction selective diffusion plate 154 and the second direction selective diffusion plate 155 can be offset by propagating light in both directions. . Therefore, even without adjusting the diffraction efficiency of the direction selective diffusion plate 151, the uniformity of the light intensity propagating along the waveguide 130 can be increased.

Figure 8 shows a display device according to another exemplary embodiment.

Components using the same reference numerals as in FIG. 1 in FIG. 8 are substantially the same as those described with reference to FIG. 1 , and therefore detailed description thereof will be omitted here.

The display device 300 includes an output coupler 350 that outputs light propagating from the waveguide 130 to the outside. The output coupler 350 includes a polarization volume grating 351 provided on one of the first side 131 and the second side 132 of the waveguide 130, and a geometric phase lens array provided on the other side of the waveguide 130. It may include (353).

Additionally, a first circular polarizer 305 may be further provided between the telecentric assembly 120 and the waveguide 130. Alternatively, the first circular polarizer 305 may be disposed between the display element 110 and the telecentric assembly 120. The first circular polarizer 305 can convert the polarization of incident light into circular polarization. For example, the first circular polarizer 305 may pass only right-handed circularly polarized light among the light incident through the telecentric assembly 120. However, it is not limited to this, and it is also possible for the first circular polarizer 305 to pass only left-hand circularly polarized light. The first circular polarizer 305 can pass right-handed circularly polarized light or left-handed circularly polarized light depending on the combination with the output coupler 350 and the second circular polarizer 355, which will be described later.

A second circular polarizer 355 may be provided spaced apart from the polarization volume grating 351. The second circular polarizer 355 may be configured to pass circularly polarized light in a direction opposite to the circularly polarized light operating in the first circular polarizer 355 . Additionally, the second circular polarizer 355 may be configured to operate on circularly polarized light opposite to the circularly polarized light operating on the polarization volume grating 351. The second circular polarizer 355 selectively transmits light entering the waveguide 130 from the outside of the display device 300, allowing the user to view an external object while wearing the display device 300. That is, the display device 300 can implement an augmented reality display device.

The operation of the display device 300 will be described.

Image light formed by the display element 110 enters the first circular polarizer 305 through the telecentric assembly 120. For example, the first circular polarizer 305 may allow only right-circularly polarized light among incident light to pass through and enter the waveguide 130. Right-circularly polarized light may be reflected from the input coupler 140, propagate through the waveguide 130, and be incident on the polarization volume grating 351. The polarization volume grating 351 can diffract only specific polarized light and directly transmit other polarized light. For example, the polarization volume grating 351 may diffract right circularly polarized light and transmit left circularly polarized light straight through. Therefore, right-circularly polarized image light incident on the polarization volume grating 351 is diffracted by the polarization volume grating 351 and enters the geometric phase lens array 353.

Geometric phased lens array 353 may operate as a lens for a particular polarization while operating as a transparent element for the conjugate polarization of a particular polarization. The geometric phase lens array 353 can implement augmented reality using light of left-circular polarization and right-circular polarization, which are conjugate polarizations. When right-circularly polarized image light is incident on the geometric phased lens array 353, the geometrical phased lens array 353 may operate as a lens for right-circularly polarized light. Accordingly, the image light can be diffused by the geometric phase lens array 353 and enter the viewer's eyes.

Meanwhile, only left circularly polarized external light incident on the second circular polarizer 355 from the outside can pass through the second circular polarizer 355. Left circularly polarized light is incident on the polarization volume grating 351, and the polarization volume grating 351 can transmit the left circularly polarized light in a straight line. Left circularly polarized light passes through the waveguide 130 and is incident on the geometric phase lens array 353. The geometric phase lens array 353 operates as a transparent element for left-hand circularly polarized light and can transmit left-hand circularly polarized light in a straight line. Through the above-described process, light coming from outside the display device 300 enters the user's eyes and allows the user to view an actual image.

As described above, the display device 300 of this embodiment can be implemented as an augmented reality display device that can view the image from the display element 110 and the actual image from outside the display device 300 together.

The display device according to an exemplary embodiment includes a telecentric assembly and can increase light uniformity by allowing light emitted from the display element to enter the waveguide at the same angle. The disclosed display device can be implemented as wearable or non-wearable.

Figure 9 shows a block diagram of an electronic device according to an exemplary embodiment. The electronic device 400 may include a display device 420 according to an example embodiment. The display device 420 may include the embodiments described with reference to FIGS. 1 to 8 . The electronic device 400 may be installed in the network environment 470. In the network environment 470, the electronic device 400 communicates with another electronic device 455, for example, a smart phone, through the network 450 (a short-range wireless communication network or a long-range wireless communication network, etc.), or with the server 460. You can communicate with.

The electronic device 400 may include a display device 420 that displays an image and an image processor 430 that processes the image. Additionally, the electronic device 400 may include a communication module 440 that can communicate with another electronic device 455 or a server 460 through the network 450. An image transmitted from another electronic device 455 can be received through the communication module 440 and displayed on the display device 420. Meanwhile, the image processor 430 may compensate for optical aberrations by considering aberrations for each position of the virtual image using an optimized hologram generation algorithm.

FIG. 10 illustrates an example in which a user wears a display device with glasses according to an exemplary embodiment. The glasses-type display device may include a display element 410 that provides an image, and a display device 420 that transmits the image provided by the display element 410 to the user's eyes. The display device 420 may be applied to the glass of glasses. Here, the display element 410 is shown independently from the display device 420, but this is for convenience of explanation, and the display device 410 may be included in the display device 420.

The display device according to the exemplary embodiment may be applied to a virtual reality (VR) device, an augmented reality (AR) device, a mixed reality (MR) device, a head-up display device, a flat panel display device, etc. . Virtual reality is a technology that makes it seem like people are interacting with their actual surroundings without directly experiencing environments that are difficult to experience on a daily basis, and augmented reality augments virtual information in real space in real time so that users can use the augmented virtual information. Work efficiency can be improved by interacting with. Mixed reality (MR) is a concept that includes virtual reality (VR) and augmented reality (AR). It mixes real space and virtual space to build a new space where real and virtual objects interact in real time. You can. It can be applied to various fields in the form of head-mounted displays (HMDs) or smart glasses by combining the immersion, which is the advantage of virtual reality, and the realism, which is the advantage of augmented reality.

A display device according to an exemplary embodiment includes a display element that emits light that displays an image; a waveguide including a first surface on which the light is incident, and a second surface opposing the first surface; an input coupler provided in the waveguide to input the light into the waveguide; a telecentric assembly provided between the display element and the waveguide and configured to equalize the angle of incidence of light incident on the input coupler; and an output coupler that outputs the light propagating within the waveguide to the outside.

The light from the display element is incident on the telecentric assembly 120 without diffusion, and the light is incident on the input coupler with a cross-sectional area equal to the area of the display element by the telecentric assembly 120. It can be configured.

The waveguide may be configured to have a thickness t that satisfies the following equation. <expression>

t = W1/ 2tan(θ)

Here, W1 represents the width of the display element, and θ represents the diffraction angle of light diffracted from the input coupler.

The telecentric assembly may include a first lens, a second lens disposed to be spaced apart from the first lens, and an optical filter provided between the first lens and the second lens.

The output coupler may include a direction-selective diffusion plate provided on one of the first and second surfaces of the waveguide, and a lens array provided on the other side of the waveguide.

The direction selective diffusion plate may include a holographic pattern configured to increase diffraction efficiency along the direction of propagation of light in the waveguide.

The output coupler may include a polarization volume grating provided on one of the first and second sides of the waveguide and a lens array provided on the other side of the waveguide.

A polarization modulation layer may be further provided between the waveguide and the lens array.

The output coupler may include a polarization volume grating provided on one of the first and second surfaces of the waveguide and a geometric phase lens array provided on the other side of the waveguide.

A circular polarizer may be further provided to be spaced apart from the polarization volume grating, and the circular polarizer may be configured to operate on circularly polarized light in an opposite direction to the circularly polarized light operating on the polarization volume grating.

A circular polarizer may be further provided between the telecentric assembly and the waveguide.

The display element includes a first display element emitting first light and a second display element emitting second light, and the first display element is arranged to make the first light incident on one side of the waveguide. , the second display element may be arranged to make the second light incident on the other side of the waveguide.

The input coupler may include a first input coupler provided to correspond to the first display element and a second input coupler provided to correspond to the second display element.

An optical element that splits the light emitted from the display element into a first optical path and a second optical path may be further provided.

The input coupler may include a first input coupler into which the light transmitted through the first optical path is incident, and a second input coupler into which the light transmitted through the second optical path is incident.

a first direction selective diffusion plate in which the output coupler outputs the first light incident on the waveguide through the first input coupler, and a second diffusion plate on which the output coupler outputs the second light incident on the waveguide through the second input coupler. It may include a direction selective diffusion plate.

The width of the display element may be the same as the width of the input coupler.

The output coupler may include a lens array, the lens array may include a plurality of lenses, and a width of each of the plurality of lenses may be equal to the width of the display element.

The above-described embodiments are merely illustrative, and various modifications and other equivalent embodiments can be made by those skilled in the art. Therefore, the true scope of technical protection according to the exemplary embodiments should be determined by the technical idea described in the following patent claims.

100,100A,100B,200,300: Display device
110,111,112: Display element
120,121,122:Telesenic assembly
130:Waveguide
140,141,142: Input coupler
150,250:350:Output coupler
151: Direction selection diffusion plate
153,253:Lens array
251,351: Polarization volume grating
255: Polarization modulation layer
305,355: Circular polarizer
353:Geometric phase lens array

Claims (18)

A display element 110 that emits light to display an image;
A waveguide 130 including a first surface on which the light is incident and a second surface opposing the first surface;
an input coupler 140 provided in the waveguide to input the light into the waveguide;
a telecentric assembly 120 provided between the display element and the waveguide and configured to equalize the angle of incidence of light incident on the input coupler; and
A display device comprising: an output coupler 150 that outputs light propagating within the waveguide to the outside. According to claim 1,
The light emitted from the display element 110 is incident on the telecentric assembly 120 without diffusion, and the light has a cross-sectional area equal to the area of the display element due to the telecentric assembly 120 and is connected to the input coupler. A display device configured to be incident on. According to claim 1 or 2,
The waveguide 130 is configured to have a thickness t that satisfies the following equation.
<expression>
t = W1/ 2tan(θ)
Here, W1 represents the width of the display element, and θ represents the diffraction angle of light diffracted from the input coupler. According to any one of claims 1 to 3,
The telecentric assembly 120 includes a first lens 121, a second lens 122 spaced apart from the first lens 121, and a space between the first lens 121 and the second lens 122. A display device including an optical filter 123 provided in . According to any one of claims 1 to 4,
The output coupler 150 includes a direction selection diffusion plate 151 provided on one of the first and second surfaces of the waveguide 130, and a lens array provided on the other side of the waveguide 130 ( 153), including a display device. According to clause 5,
The direction selective diffusion plate (151) includes a holographic pattern configured to increase diffraction efficiency along the direction of propagation of light in the waveguide (130). According to any one of claims 1 to 4,
The output coupler 250 includes a polarization volume grating 251 provided on one of the first and second sides of the waveguide 130 and a lens array 253 provided on the other side of the waveguide 130. Including, a display device. According to clause 7,
A display device further comprising a polarization modulation layer (255) between the waveguide (130) and the lens array (253). According to any one of claims 1 to 4,
The output coupler 350 includes a polarization volume grating 351 provided on one of the first and second sides of the waveguide 130, and a geometric phase lens array 353 provided on the other side of the waveguide 130. ), including a display device. According to clause 9,
A circular polarizer 355 is further provided to be spaced apart from the polarization volume grating 351, and the circular polarizer 355 is configured to operate on circular polarization opposite to the circular polarization operating on the polarization volume grating 351, Display device. According to clause 9,
A display device further comprising a circular polarizer (305) between the telecentric assembly (120) and the waveguide (130). According to any one of claims 1 to 4,
The display element 110 includes a first display element 111 that emits first light and a second display element 112 that emits second light, and the first display element is positioned on one side of the waveguide. A display device arranged to make first light incident, and wherein the second display element is arranged to make the second light incident to the other side of the waveguide. According to claim 12,
The input coupler 140 includes a first input coupler 141 provided to correspond to the first display element 111, and a second input coupler 142 provided to correspond to the second display element 112. Including, a display device. According to any one of claims 1 to 4,
A display device further comprising an optical element 160 that splits the light emitted from the display element 110 into a first optical path and a second optical path. According to claim 14,
The input coupler 140 includes a first input coupler 141 into which the light transmitted through the first optical path is incident, and a second input coupler 142 into which the light transmitted through the second optical path is incident. , display device. According to claim 15,
A first direction selection diffusion plate 154 through which the output coupler 150 outputs the first light incident on the waveguide 130 through the first input coupler 141, and the second input coupler 142 A display device comprising a second direction selective diffusion plate 155 that outputs the second light incident on the waveguide 130 through. According to any one of claims 1 to 16,
A display device wherein the width of the display element (110) is equal to the width of the input coupler (140). According to any one of claims 1 to 17,
A display wherein the output coupler 150 includes a lens array 153, the lens array 153 includes a plurality of lenses 152, and the width of each of the plurality of lenses is equal to the width of the display element. Device.

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