Lens assembly and display device

Abstract

The utility model relates to a lens assembly and a display device. The lens assembly includes an incident side on which light is incident and an exit side opposite to the incident side, the lens assembly including: a first polarization layer disposed adjacent to the incident side; a second polarization layer provided between the first polarization layer and the exit side; and a phase retardation layer disposed between the first polarization layer and the second polarization layer. The phase retardation layer has a first phase retardation refractive index along a first direction, a second phase retardation refractive index along a second direction equal to the first phase retardation refractive index, and a third phase retardation refractive index along a third direction perpendicular to the first direction and the second direction, and the first phase delay refractive index and the second phase delay refractive index are different from the third phase delay refractive index.

Description

Technical Field

[0001] The present disclosure relates to a lens assembly and a display device including the lens assembly. Background Art

[0002] As information technology has developed, the importance of display devices as a connection medium between users and information has become prominent. Accordingly, the use of display devices such as liquid crystal display devices and organic light emitting display devices has been increasing.

[0003] Recently, as a type of display device, a head-mounted display (HMD) has been developed. A head-mounted display is a display device that is worn on a user's head and provides an image, and is currently available on the market and widely used in various fields including the entertainment industry.

[0004] For example, a head-mounted display can be used in various applications such as virtual reality (VR) and augmented reality (AR).

[0005] Recently, methods for improving the display quality of head-mounted displays have been continuously studied. For example, methods for reducing ghost images are being studied to provide users with virtual reality and augmented reality that are closer to reality. Summary of the Utility Model

[0006] Embodiments of the present disclosure provide a lens assembly and a display device including the lens assembly that can improve display quality.

[0007] Embodiments of the present disclosure provide a lens assembly including an incident side where light enters and an exit side opposite to the incident side, characterized in that the lens assembly includes: a first polarization layer disposed adjacent to the incident side; a second polarization layer disposed between the first polarization layer and the exit side; and a phase retardation layer disposed between the first polarization layer and the second polarization layer. In such an embodiment, the phase retardation layer has a first phase retardation refractive index along a first direction, has a second phase retardation refractive index equal to the first phase retardation refractive index along a second direction, and has a third phase retardation refractive index along a third direction perpendicular to the first direction and the second direction, and the first phase retardation refractive index and the second phase retardation refractive index are different from the third phase retardation refractive index.

[0008] In an embodiment, the lens assembly may further include: a first quarter-wave plate disposed between the second polarization layer and the exit side; a partial mirror layer disposed between the first quarter-wave plate and the exit side; a second quarter-wave plate disposed between the partial mirror layer and the exit side; and a third polarization layer disposed adjacent to the exit side.

[0009] In an embodiment, relative to visible light, the phase retardation layer may have a phase retardation value in the range of 500 nm to 1500 nm, wherein the phase retardation value of the phase retardation layer is represented by R th and satisfies the following equation: R th ={(N X +N Y ) / 2 - N Z}×d, where N X represents the first phase retardation refractive index, N Y represents the second phase retardation refractive index, N Z represents the third phase retardation refractive index, and d represents the thickness of the phase retardation layer. Each of the first phase retardation refractive index to the third phase retardation refractive index is in the range of 1.5 to 1.9.

[0010] In an embodiment, the phase retardation layer may change the polarization state of light incident in a direction different from the third direction, and the first direction and the second direction may be the same as the direction in which the plane in which the phase retardation layer is disposed extends.

[0011] In an embodiment, the optical transmission axes of the first polarizing layer and the second polarizing layer may be parallel to each other.

[0012] In an embodiment, the first polarizing layer may be a linear polarizing layer.

[0013] In an embodiment, the first polarizing layer may be in the form of a film and the first polarizing layer and the phase retardation layer may be spaced apart from each other.

[0014] In an embodiment, the lens assembly may further include: an adhesive layer disposed between the first polarizing layer and the phase retardation layer. The phase retardation layer may be coupled to the first polarizing layer through the adhesive layer.

[0015] In an embodiment, the phase retardation layer and the first polarizing layer may be in contact with each other.

[0016] In an embodiment, the display device may include: a display panel including a substrate layer disposed on a plane defined by a first direction and a second direction different from the first direction, and a light-emitting element disposed on the substrate layer; and the above-described lens assembly disposed on the display panel. The lens assembly may transmit light provided from the display panel.

[0017] Embodiments of the present disclosure provide a lens assembly, including an incident side for light incidence and an exit side opposite to the incident side. Wherein, the lens assembly includes: a first polarization layer disposed adjacent to the incident side; a second polarization layer disposed between the first polarization layer and the exit side; a phase retardation layer disposed between the first polarization layer and the second polarization layer; a first quarter-wave plate disposed between the second polarization layer and the exit side; a partial mirror layer disposed between the first quarter-wave plate and the exit side; a second quarter-wave plate disposed between the partial mirror layer and the exit side; and a third polarization layer disposed adjacent to the exit side. In such an embodiment, the phase retardation layer has a first phase retardation refractive index along a first direction, a second phase retardation refractive index equal to the first phase retardation refractive index along a second direction, and a third phase retardation refractive index along a third direction perpendicular to the first direction and the second direction, and the first phase retardation refractive index and the second phase retardation refractive index are different from the third phase retardation refractive index.

[0018] In an embodiment, the phase retardation layer may include a material having refractive index anisotropy.

[0019] In an embodiment, with respect to visible light, the phase retardation layer may have a phase retardation value (R th ) in the range of about 500 nm to about 1500 nm. In such an embodiment, the phase retardation value (R th ) of the phase retardation layer satisfies the following equation: R th = {(N X + N Y ) / 2 - N Z} × d, where N X represents the first phase retardation refractive index, N Y represents the second phase retardation refractive index, N Z represents the third phase retardation refractive index, and d represents the thickness of the phase retardation layer.

[0020] In an embodiment, the material having refractive index anisotropy may include discotic materials or liquid crystal materials.

[0021] In an embodiment, the first phase retardation refractive index to the third phase retardation refractive index may be in the range of about 1.5 to about 1.9.

[0022] In an embodiment, the phase retardation layer may change the polarization state of light incident in a direction different from the third direction, and the first direction and the second direction may be the same as the direction in which the plane of the phase retardation layer extends.

[0023] In an embodiment, the optical transmission axis of the first polarization layer and the optical transmission axis of the second polarization layer may be parallel to each other.

[0024] In an embodiment, the first polarization layer may be a linear polarization layer.

[0025] In an embodiment, the first polarization layer may be in the form of a film.

[0026] In an embodiment, the first polarization layer and the phase retardation layer may be spaced apart from each other.

[0027] In an embodiment, a material having refractive index isotropy may be disposed between the first polarization layer and the phase retardation layer.

[0028] In an embodiment, the lens assembly may further include an adhesive layer disposed between the first polarization layer and the phase retardation layer, wherein the phase retardation layer may be coupled to the first polarization layer through the adhesive layer.

[0029] In an embodiment, the phase retardation layer and the first polarization layer may be in contact with each other.

[0030] In an embodiment, the phase retardation layer may be a layer formed on the first polarization layer by a coating or deposition process.

[0031] Another embodiment of the present disclosure provides a display device, the display device including: a display panel including a substrate layer disposed on a plane defined by a first direction and a second direction different from the first direction, and a light-emitting element disposed on the substrate layer; and a lens assembly disposed on the display panel, wherein the lens assembly transmits light provided from the display panel, and the lens assembly includes an incident side adjacent to the display panel and an exit side opposite to the incident side. In such an embodiment, the lens assembly includes: a first polarization layer disposed adjacent to the incident side; a second polarization layer disposed between the first polarization layer and the exit side; a phase retardation layer disposed between the first polarization layer and the second polarization layer; a first quarter-wave plate disposed between the second polarization layer and the exit side; a partial mirror layer disposed between the first quarter-wave plate and the exit side; a second quarter-wave plate disposed between the partial mirror layer and the exit side; and a third polarization layer disposed adjacent to the exit side. In such an embodiment, the phase retardation layer has a first phase retardation refractive index along the first direction, a second phase retardation refractive index equal to the first phase retardation refractive index along the second direction, and a third phase retardation refractive index along a third direction perpendicular to the first direction and the second direction, and the first phase retardation refractive index and the second phase retardation refractive index are different from the third phase retardation refractive index.

[0032] In an embodiment, with respect to visible light, the phase retardation layer may have a phase retardation value (R th ) in a range of about 500 nm to about 1500 nm. In such an embodiment, the phase retardation value (R th ) of the phase retardation layer satisfies the following equation: R th = {(N X + N Y ) / 2 - N Z} × d, where N X represents the first phase retardation refractive index, N Y represents the second phase retardation refractive index, N Z represents the third phase retardation refractive index, and d represents the thickness of the phase retardation layer.

[0033] In an embodiment, the phase retardation layer may include a material having refractive index anisotropy, and the phase retardation layer changes the polarization state of light incident in a direction different from the third direction.

[0034] In an embodiment, the optical transmission axes of the first polarization layer, the second polarization layer, and the third polarization layer may be parallel to each other.

[0035] Another embodiment of the present disclosure provides a lens assembly configured to guide light, and including an incident side where light enters and an exit side opposite to the incident side. The lens assembly includes: a first polarization layer disposed adjacent to the incident side; a second polarization layer disposed between the first polarization layer and the exit side; and a phase retardation layer disposed between the first polarization layer and the second polarization layer. In such an embodiment, the phase retardation layer has a first phase retardation refractive index along a first direction, a second phase retardation refractive index equal to the first phase retardation refractive index along a second direction, and a third phase retardation refractive index along a third direction perpendicular to the first direction and the second direction, and the first phase retardation refractive index and the second phase retardation refractive index are different from the third phase retardation refractive index.

[0036] In an embodiment, with respect to visible light, the phase retardation layer may have a phase retardation value (R th ) in the range of about 500 nm to about 1500 nm. In such an embodiment, the phase retardation value (R th ) of the phase retardation layer satisfies the following equation: R th = {(N X + N Y ) / 2 - N Z} × d, where N X represents the first phase retardation refractive index, N Y represents the second phase retardation refractive index, N Z represents the third phase retardation refractive index, and d represents the thickness of the phase retardation layer.

[0037] According to an embodiment of the present disclosure, a lens assembly that can improve display quality and a display device including the lens assembly can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A display device according to an embodiment is schematically illustrated.

[0039] Figure 2 A schematic top plan view of a display panel according to an embodiment is shown.

[0040] Figure 3 A schematic cross-sectional view of a lens assembly according to an embodiment is shown.

[0041] Figure 4 The light paths of side light and front light emitted from the display panel are schematically illustrated.

[0042] Figures 5A to 5FShows the TECH WIZ 1D simulation results of the outgoing light according to the presence or absence of the phase delay layer and the phase delay value of the phase delay layer.

[0043] Figure 6 Schematically shows the path where the light path is folded.

[0044] Figure 7 Shows a schematic cross-sectional view of a lens assembly according to another embodiment.

[0045] Figure 8 Shows a schematic cross-sectional view of a lens assembly according to another embodiment.

[0046] Figure 9 and Figure 10 Schematically shows an embodiment of an electronic device of a display device to which Figure 1 can be applied.

[0047] Figure 11 Schematically shows an embodiment of a head-mounted display worn on a user. Detailed Description

[0048] The present invention will now be described more fully hereinafter with reference to the accompanying drawings showing various embodiments. However, the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present invention to those skilled in the art. Like reference numerals always refer to like elements.

[0049] It will be understood that when an element is referred to as being "on" another element, the element may be directly on the other element, or there may be intervening elements between the element and the other element. Conversely, when an element is referred to as being "directly" on another element, there are no intervening elements.

[0050] It will be understood that although the terms "first", "second", "third", etc. may be used herein to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Thus, without departing from the teachings herein, the "first element", "first component", "first region", "first layer" or "first part" discussed below may be referred to as a second element, second component, second region, second layer or second part.

[0051] The terms used in this specification are for the purpose of describing particular embodiments only and are not intended to be limiting. Unless the context clearly dictates otherwise, as used herein, "a," "an," "the," and "at least one" do not denote a limitation of quantity and are intended to include both the singular and the plural. Thus, a reference to "an" element in a claim after a reference to "the" element includes one element and a plurality of the elements. For example, unless the context clearly dictates otherwise, "element" and "at least one element" have the same meaning. "At least one" should not be construed as limiting "a" or "an." "Or" means "and / or." As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. It will also be understood that when used in this specification, the terms "comprises" and / or "comprising," or "includes" and / or "including" specify the presence of the stated features, regions, wholes, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, regions, wholes, steps, operations, elements, components, and / or groups thereof.

[0052] Moreover, relative terms such as "lower" or "bottom" and "upper" or "top" may be used herein to describe the relationship of one element to another element as shown in the figures. It will be understood that relative terms are also intended to cover different orientations of the device in addition to the orientation depicted in the figures. For example, if the device in a figure is flipped, then an element described as on the "lower" side of other elements will then be oriented on the "upper" side of the other elements. Thus, depending on the particular orientation of the figure, the term "lower" can cover both the "lower" and "upper" orientations. Similarly, if the device in a figure is flipped, then an element described as "beneath" or "under" other elements will then be oriented "above" the other elements. Thus, the terms "beneath" or "under" can cover both the above and below orientations.

[0053] Taking into account the measured values being discussed and the errors associated with the measurement of a particular quantity (i.e., the limitations of the measurement system), "about" or "approximate" as used herein includes the stated value and represents within an acceptable deviation range of the particular value as determined by a person of ordinary skill in the art. For example, "about" can mean within one or more standard deviations, or within ±30%, ±20%, ±10%, or ±5% of the stated value.

[0054] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. It should also be understood that terms, such as those defined in a general dictionary, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and this disclosure, and should not be interpreted in an idealized or overly formal sense, unless expressly so defined herein.

[0055] Embodiments are described herein with reference to cross-sectional views that are schematic illustrations of idealized embodiments. As such, variations in the shapes of the illustrations due to, for example, manufacturing techniques and / or tolerances are to be expected. Accordingly, the embodiments described herein should not be construed as limited to the particular shapes of regions shown herein, but are to include deviations in shapes resulting from, for example, manufacturing. For example, regions shown or described as flat will generally have rough and / or non-linear features. Additionally, sharp corners shown may be rounded. Thus, the regions shown in the figures are schematic in nature, and their shapes are not intended to show the exact shape of a region and are not intended to limit the scope of the claims.

[0056] Hereinafter, a lens assembly according to an embodiment and a display device including the lens assembly will be described with reference to the drawings.

[0057] First, reference will be made to Figure 1 briefly describe the configuration included in the display device DD.

[0058] Figure 1 A display device according to an embodiment is schematically shown.

[0059] In an embodiment, the display device DD may include a display panel DP and a lens assembly OCP.

[0060] The display panel DP is configured to emit light. In some embodiments, the display panel DP may display moving images or still images. The display panel DP may be used as a display screen of a portable electronic device such as a mobile phone, a smart phone, a tablet personal computer (PC), a smart watch, a watch phone, a mobile communication terminal, an electronic note, an e-book, a portable multimedia player (PMP), a navigation device, and an ultra-mobile PC (UMPC), and may be used as a display screen of various products such as a television, a laptop computer, a monitor, a billboard, and an Internet of Things (IoT) device. However, the application fields of the display panel DP are not limited to specific examples.

[0061] The lens assembly OCP can transmit the light provided (or emitted) from the display panel DP. The lens assembly OCP can guide the light provided from the display panel DP. The lens assembly OCP can guide the light provided from the display panel DP to increase the area (viewing window or eye box) where the user can observe the image. Thus, the lens assembly OCP can effectively provide virtual reality or augmented reality to the user.

[0062] The lens assembly OCP can be disposed on the display panel DP. In some embodiments, the lens assembly OCP can be disposed at a predetermined distance from the display panel DP. In some embodiments, the lens assembly OCP can be directly disposed on the display panel DP.

[0063] Hereinafter, reference will be made to Figure 2 describe the display panel DP of the display device DD.

[0064] Figure 2 A schematic top plan view of a display panel according to an embodiment is shown.

[0065] Refer to Figure 2 , an embodiment of the display panel DP includes a substrate layer BSL on a plane defined by a first direction DR1 and a second direction DR2 intersecting the first direction DR1, and a light-emitting element disposed on the substrate layer BSL.

[0066] The display panel DP can be formed in a flat shape having a rectangular shape, the rectangular shape having a short side in the first direction DR1 and a long side in a second direction DR2 (different from the first direction DR1) intersecting the first direction DR1. The corners where the short side of the first direction DR1 and the long side of the second direction DR2 intersect can be rounded to have a predetermined curvature, or can be formed to have a right angle. The flat shape of the display panel DP is not limited to a quadrilateral shape, and can be formed in a rounded shape such as another polygon shape, a circular shape, or an elliptical shape. The display panel DP can be formed flat, but is not limited thereto. In an embodiment, for example, the display panel DP can include curved portions formed at the left and right ends and have a constant curvature or a variable curvature. In addition, the display panel DP can be formed to be flexible (e.g., can be bent, curved, folded, or curled).

[0067] In the present disclosure, the first direction DR1 is the row direction of the pixels PXL, and can also be referred to as the "horizontal" direction. The second direction DR2 can be the column direction of the pixels PXL, and can also be referred to as the "vertical" direction. The first direction DR1 and the second direction DR2 can be perpendicular to each other. The third direction DR3 can be the display direction of the display panel DP, or the normal direction of the plane of the substrate layer BSL. The third direction DR3 can be the thickness direction of the display panel DP or the substrate layer BSL.

[0068] The display panel DP may include a display area DA and a non-display area NDA. The non-display area NDA may represent an area other than the display area DA. The non-display area NDA may surround at least a part of the display area DA.

[0069] The display area DA may represent an area where pixels PXL are provided. The non-display area NDA may represent an area where pixels PXL are not provided. In the non-display area NDA, a driving circuit portion, wirings, and pads connected to the pixels PXL in the display area DA may be provided.

[0070] In some embodiments, a pixel PXL (or a sub-pixel SPX) may include a first sub-pixel SPX1, a second sub-pixel SPX2, and a third sub-pixel SPX3. At least one selected from the first sub-pixel SPX1, the second sub-pixel SPX2, and the third sub-pixel SPX3 may form or jointly define a pixel unit PXU capable of emitting light of various colors. Figure 2 An embodiment is shown in which each of a plurality of pixels PXL includes three sub-pixels SPX1, SPX2, and SPX3 (i.e., a first sub-pixel SPX1, a second sub-pixel SPX2, and a third sub-pixel SPX3), but the present utility model is not limited thereto.

[0071] In some embodiments, pixels PXL (or sub-pixels SPX) may be arranged according to a stripe or arrangement structure. However, the present disclosure is not necessarily limited thereto.

[0072] The first sub-pixel SPX1 may emit first light, the second sub-pixel SPX2 may emit second light, and the third sub-pixel SPX3 may emit third light. Here, the first light may be light in a red wavelength band, the second light may be light in a green wavelength band, and the third light may be light in a blue wavelength band. The red wavelength band is a band of approximately 600 nanometers (nm) to approximately 750 nm, the green wavelength band is a band of approximately 480 nm to approximately 560 nm, and the blue wavelength band may be a band of approximately 370 nm to approximately 460 nm, but is not limited thereto.

[0073] Each of the first sub-pixel SPX1, the second sub-pixel SPX2, and the third sub-pixel SPX3 may include an inorganic light-emitting element containing an inorganic semiconductor, or an organic light-emitting diode (OLED), as a light-emitting element that emits light. However, the embodiments of the specification are not limited thereto.

[0074] Hereinafter, a lens assembly OCP according to an embodiment will be described with reference to Figures 3 to 6 description.

[0075] Figure 3Shows a schematic cross-sectional view of a lens assembly according to an embodiment. Figure 4 Schematically shows the light paths of side light and front light emitted from a display panel. Figure 4 Shows Figure 3 regions S1 and the display panel DP. Figures 5A to 5F Shows the TECH WIZ 1D simulation results of the emitted light according to the presence or absence of a phase retardation layer and the phase retardation value of the phase retardation layer. Figure 6 Schematically shows the path where the light path is folded. Figure 6 Shows Figure 3 region S2.

[0076] As a reference, TECH WIZ is one of multiple optical simulation programs known in the art.

[0077] Referring Figure 3 , the lens assembly OCP may include an incident side A1 that can be disposed adjacent to the display panel DP in a third direction DR3 (e.g., see Figure 1 ), and an exit side A2 opposite to the incident side A1.

[0078] The lens assembly OCP may include a first polarization layer POL1, a phase retardation layer RTHL, a second polarization layer POL2, a first quarter-wave plate QWP1, a partial mirror layer HFM, a second quarter-wave plate QWP2, and a third polarization layer POL3. In some embodiments, the lens assembly OCP may have a structure in which the first polarization layer POL1, the phase retardation layer RTHL, the second polarization layer POL2, the first quarter-wave plate QWP1, the partial mirror layer HFM, the second quarter-wave plate QWP2, and the third polarization layer POL3 are sequentially disposed.

[0079] In the drawings of the present disclosure, the components of the lens assembly OCP are shown as having flat surfaces, and the cross-sections of the components of the lens assembly OCP are shown as having a quadrilateral shape, but the present disclosure is not limited thereto. In some embodiments, each of the multiple components of the lens assembly OCP may have a concave surface or a convex surface, and the cross-section of each of the multiple components of the lens assembly OCP may be concave or convex.

[0080] In an embodiment of the lens assembly OCP, the first polarization layer POL1 may be disposed on the display panel DP with respect to the third direction DR3. The first polarization layer POL1 may be disposed adjacent to the incident side A1. In an embodiment, for example, the first polarization layer POL1 may be disposed closer to the display panel DP than the second polarization layer POL2. In some embodiments, the first polarization layer POL1 and the display panel DP may be physically spaced apart from each other. The first polarization layer POL1 and the display panel DP may not be in contact with each other. However, the present disclosure is not limited thereto. In an embodiment, the first polarization layer POL1 may be directly disposed on the display panel DP to be in contact with the display panel DP.

[0081] The first polarization layer POL1 may have a transmission axis (e.g., a light transmission axis) (or a through axis) aligned along a predetermined direction. For example, the first polarization layer POL1 may have a transmission axis aligned along the fourth direction DR4, which is a direction perpendicular to the third direction DR3. The fourth direction DR4 may be parallel to Figure 2 the first direction DR1 or the second direction DR2 shown in. The first polarization layer POL1 may be a linear polarization layer. The first polarization layer POL1 may be in the form of a film. The first polarization layer POL1 may linearly polarize unpolarized or partially polarized light emitted from the display panel DP. In an embodiment, for example, the first polarization layer POL1 may transmit only the component of light vibrating along the transmission axis of the first polarization layer POL1 and may not transmit the remaining component of the light. Thus, as the light emitted from the display panel DP passes through the first polarization layer POL1, the light may be aligned with the transmission axis of the first polarization layer POL1 and be linearly polarized.

[0082] The second polarization layer POL2 may be disposed on the first polarization layer POL1 with respect to the third direction DR3. The second polarization layer POL2 may be disposed between the exit side A2 and the first polarization layer POL1. The second polarization layer POL2 may be disposed farther from the incident side A1 than the first polarization layer POL1. For example, the second polarization layer POL2 may be disposed closer to the exit side A2 than the first polarization layer POL1. The second polarization layer POL2 may be disposed farther from the display panel DP than the first polarization layer POL1.

[0083] The second polarization layer POL2 may have a transmission axis (or a through-axis) aligned along a predetermined direction. The second polarization layer POL2 may have a transmission axis in the same direction as the first polarization layer POL1 (or the transmission axes of the first polarization layer POL1 and the second polarization layer POL2 are parallel to each other). In an embodiment, for example, the second polarization layer POL2 may have a transmission axis aligned along the fourth direction DR4. The second polarization layer POL2 may be a linear polarization layer. The second polarization layer POL2 may linearly polarize the light passing through the second polarization layer POL2. For example, the second polarization layer POL2 may transmit only the component of the light vibrating along the transmission axis of the second polarization layer POL2 and may not transmit the remaining component of the light.

[0084] The retardation layer RTHL may be disposed on the first polarization layer POL1 with respect to the third direction DR3. The retardation layer RTHL may be disposed adjacent to the first polarization layer POL1. The retardation layer RTHL may be disposed between the first polarization layer POL1 and the second polarization layer POL2. The retardation layer RTHL may be disposed to be spaced apart from the first polarization layer POL1 and the second polarization layer POL2 and between the first polarization layer POL1 and the second polarization layer POL2. The retardation layer RTHL may not be in contact with the first polarization layer POL1 and the second polarization layer POL2.

[0085] A material having an isotropic refractive index (or a material with an isotropic refractive index) may be filled between the retardation layer RTHL and the first polarization layer POL1 and between the retardation layer RTHL and the second polarization layer POL2. In an embodiment, for example, air may be filled between the retardation layer RTHL and the first polarization layer POL1 and between the retardation layer RTHL and the second polarization layer POL2.

[0086] The retardation layer RTHL may have a retardation value within a numerical range. The retardation value may be represented by Equation 1 below.

[0087]

Equation 1

[0088] R th ={(N X +N Y ) / 2-N Z}×d

[0089] In Equation 1, R th represents the retardation value of the retardation layer RTHL, N X represents the refractive index of the retardation layer RTHL in the first direction DR1, N Y represents the refractive index of the retardation layer RTHL in the second direction DR2, N Zrepresents the refractive index of the phase retardation layer RTHL in the third direction DR3, and d represents the thickness D of the phase retardation layer RTHL.

[0090] In the present disclosure, the thickness D is defined in the third direction DR3, and the first direction DR1 and the second direction DR2 are the same as the directions in which the plane on which the phase retardation layer RTHL is provided extends. Further, N in Equation 1 X , N Y and N Z are respectively defined as the first phase retardation refractive index, the second phase retardation refractive index, and the third phase retardation refractive index. The phase retardation layer RTHL may have a first phase retardation refractive index (N X ) along the first direction DR1. The phase retardation layer RTHL may have a second phase retardation refractive index (N Y ) along the second direction DR2. The phase retardation layer RTHL may have a third phase retardation refractive index (N Z ) along the third direction DR3 perpendicular to the first direction DR1 and the second direction DR2.

[0091] The first phase retardation refractive index (N X ) and the second phase retardation refractive index (N Y ) are the refractive indices of the plane of the phase retardation layer RTHL (for example, the plane on which the phase retardation layer RTHL is provided), and may have the same value as each other. The third phase retardation refractive index (N Z ) is the refractive index in the thickness direction (for example, the third direction DR3), and may have a different value from the first phase retardation refractive index (N X ) and the second phase retardation refractive index (N Y ). The third phase retardation refractive index (N Z ) may have an anisotropic refractive index with respect to the first phase retardation refractive index (N X ) and the second phase retardation refractive index (N Y ). Thus, the polarization state of light incident on the phase retardation layer RTHL can be changed by forming an angle with respect to the third direction DR3 (or along a direction different from the third direction DR3).

[0092] In some embodiments, each of the first phase retardation refractive index, the second phase retardation refractive index, and the third phase retardation refractive index may be in the range of about 1.5 to about 1.9. However, the present disclosure is not limited thereto.

[0093] Relative to visible light (e.g., light having a wavelength of approximately 400 nm to approximately 700 nm), the phase retardation layer RTHL can have a phase retardation value in the range of approximately 500 nm to approximately 1500 nm. The phase retardation value can be determined according to process conditions. For example, when the liquid crystal with a value of approximately 0.15 of “(N X +N Y ) / 2 - N Z ” is vertically oriented, and the phase retardation layer RTHL has a thickness of approximately 3.5 micrometers (μm), the phase retardation value can be approximately 525 nm (= 0.15 × 3.5 μm).

[0094] The phase retardation layer RTHL can include a material having refractive index anisotropy. In an embodiment, for example, the material having refractive index anisotropy can include a liquid crystal material. In an embodiment, for example, the material having refractive index anisotropy can include a reactive liquid crystal element. In an embodiment, for example, the material having refractive index anisotropy can include a discotic material (e.g., discotic liquid crystal element).

[0095] In some embodiments, the phase retardation layer RTHL can be a film layer. The phase retardation layer RTHL can be a single film layer.

[0096] Referring to Figure 4 , the display panel DP (e.g., the light-emitting element of the display panel DP) can emit light similar to Lambertian distribution, and the light emitted from the display panel DP can include front light FLGT and side light SLGT.

[0097] Experimentally, when the display device DD (see Figure 1 ) is implemented as a head-mounted display, the front light FLGT and side light SLGT emitted from the display panel DP can form images for providing virtual reality and augmented reality to the user. For example, the front light FLGT and side light SLGT emitted from the display panel DP can pass through the lens assembly OCP (see Figure 3 ) and form images in front of the user's eyes.

[0098] The front light FLGT is the light emitted in the direction perpendicular to the display panel DP, and can be parallel to the third direction DR3. The side light SLGT is the light emitted in a direction not perpendicular to the display panel DP, and can be emitted in a direction forming an angle with respect to the third direction DR3.

[0099] Experimentally, when the display device DD is implemented as a head-mounted display, the front light FLGT can be light that forms a focus in front of the user's eyes and can be main ray angle (CRA) light that enters the user's viewing angle (or eyebox). Since the side light SLGT may not form an appropriate focus, the side light SLGT may form a ghost image to provide a virtual image to the user and may cause the light emitted from the light-emitting element to be mixed.

[0100] The display device DD according to an embodiment of the present disclosure can minimize the loss of the front light FLGT while appropriately minimizing the amount of the side light SLGT emitted outside the lens assembly OCP. Accordingly, the display quality of the display device DD can be improved.

[0101] When the front light FLGT is emitted from the display panel DP, passes through the first polarization layer POL1, and passes through the retardation layer RTHL, the front light FLGT is parallel to the third direction DR3 such that the front light FLGT can pass through without changing the individual light information. That is, when the front light FLGT passes through the retardation layer RTHL, the front light FLGT can pass through the retardation layer RTHL without changing the polarization state of the front light FLGT. Accordingly, since the polarization state of the front light FLGT that has passed through the retardation layer RTHL is not changed, the front light FLGT can pass through the second polarization layer POL2. Hereinafter, the light that has passed through the second polarization layer POL2 is defined as "second polarization layer passing light LGT".

[0102] In such an embodiment, when the side light SLGT is emitted from the display panel DP and passes through the first polarization layer POL1 and the retardation layer RTHL, since the side light SLGT is incident at an angle with respect to the third direction DR3, the polarization state can be changed according to the retardation value. That is, when the side light SLGT passes through the retardation layer RTHL, the polarization state of the side light SLGT can be changed. Accordingly, among the components of the side light SLGT whose polarization state has been changed after passing through the retardation layer RTHL, the components that do not vibrate along the transmission axis of the second polarization layer POL2 can be blocked by the second polarization layer POL2. In other words, the polarization state of the side light SLGT can be changed by passing through the retardation layer RTHL, and at least a part of the side light SLGT that vibrates in a direction different from the transmission axis of the second polarization layer POL2 may not be allowed to pass through the second polarization layer POL2.

[0103] In this regard, reference will be made to Figures 5A to 5F and in conjunction with Figure 1 、 Figure 3 and Figure 4 Describe the simulation results of the optical information according to the presence or absence of the retardation layer RTHL and the retardation value of the retardation layer RTHL. Figures 5A to 5FShows the TECH WIZ1D simulation results of the emitted light according to the presence or absence of the phase retardation layer RTHL and the phase retardation value of the phase retardation layer RTHL. Hereinafter, Figures 5A to 5F the simulation results shown in are respectively defined as the first image 5A to the sixth image 5F.

[0104] In Figures 5A to 5F the first image 5A is the simulation result of the light emitted from the lens assembly OCP that does not provide the phase retardation layer RTHL. The second image 5B is the simulation result of the light emitted from the lens assembly OCP in which the phase retardation layer RTHL is set to have a phase retardation value of 300 nm. The third image 5C is the simulation result of the light emitted from the lens assembly OCP in which the phase retardation layer RTHL is set to have a phase retardation value of 500 nm. The fourth image 5D is the simulation result of the light emitted from the lens assembly OCP in which the phase retardation layer RTHL is set to have a phase retardation value of 1000 nm. The fifth image 5E is the simulation result of the light emitted from the lens assembly OCP in which the phase retardation layer RTHL is set to have a phase retardation value of 1500 nm. The sixth image 5F is the simulation result of the light emitted from the lens assembly OCP in which the phase retardation layer RTHL is set to have a phase retardation value of 1800 nm.

[0105] These images show the viewing angle distribution of the transmittance for each light. For each brightness and darkness, the transmittance of the light corresponds to Vlax shown on the right, and the unit of the transmittance is a.u. (arbitrary unit).

[0106] Comparing the first image 5A with the second image 5B to the sixth image 5F, it can be seen that the first image 5A has a dark result value (for example, a value of Vlax 30 to 40) in a relatively large area corresponding to the center when compared with the second image 5B to the sixth image 5F. In the TECH WIZ 1D simulation results, the relatively dark result values corresponding to the values of Vlax 30 to 40 are widely distributed in the central region, which means a large emission degree of the side light SLGT from the emitted light. That is, comparing the first image 5A with the second image 5B to the sixth image 5F, it can be seen that more side light SLGT may be generated in the lens assembly OCP without the phase retardation layer RTHL.

[0107] Comparing the second image 5B with the third image 5C, it can be seen that the second image 5B has a dark result value in a relatively large area when compared with the third image 5C. This may be because when the phase retardation value of the phase retardation layer RTHL is less than 500 nm, only a small amount of the sidelight SGLT in the outgoing light is blocked. Experimentally, when only a small amount of the sidelight SGLT in the outgoing light is blocked, a ghost image may often be formed. Therefore, when the phase retardation layer RTHL is formed to have a phase retardation value less than 500 nm, only a small amount of the sidelight SGLT is blocked, making it possible to often form a ghost image.

[0108] Comparing the fifth image 5E with the sixth image 5F, it can be seen that the sixth image 5F has a relatively narrow black result value (e.g., values of Vlax 0 to 5) in the area adjacent to the edge region in the diagonal direction when compared with the fifth image 5E. Experimentally, the reduction of the black part (e.g., the area with values of Vlax 0 to 5) in the edge region may mean a decrease in the brightness of the outgoing light. Therefore, this may indicate that when the phase retardation value of the phase retardation layer RTHL exceeds 1500 nm, the brightness of the display device DD may be excessively reduced. As a result, when the phase retardation layer RTHL is formed to have a phase retardation value exceeding 1500 nm, the brightness of the display device DD may be excessively reduced to deteriorate the quality of the display device DD.

[0109] Therefore, it is desirable to design or set the phase retardation layer RTHL by selecting an appropriate range of phase retardation values that can appropriately block the sidelight SLGT without excessively reducing the brightness.

[0110] Referring to Figure 3 and Figure 6 In an embodiment of the lens assembly OCP, the first quarter-wave plate QWP1 may be disposed on the second polarization layer POL2 with respect to the third direction DR3. The first quarter-wave plate QWP1 may be disposed adjacent to the second polarization layer POL2. The first quarter-wave plate QWP1 may be disposed between the second polarization layer POL2 and the outgoing side A2. In some embodiments, the first quarter-wave plate QWP1 may be physically spaced apart from the second polarization layer POL2. The first quarter-wave plate QWP1 may not contact the second polarization layer POL2.

[0111] The first quarter-wave plate QWP1 may have an optical axis aligned at approximately 45 degrees with respect to the transmission axes of the first polarization layer POL1 and the second polarization layer POL2. By providing a phase difference of λ / 4, the first quarter-wave plate QWP1 can change linearly polarized light to circularly polarized light, or change circularly polarized light to linearly polarized light. In an embodiment, for example, when the light LGT passing through the second polarization layer is linearly polarized light at 0°, and when the light LGT passing through the second polarization layer passes through the first quarter-wave plate QWP1, the light LGT passing through the second polarization layer can become a first light L1 that is left-handed circularly polarized (LCP). In some embodiments, when the light LGT passing through the second polarization layer passes through the first quarter-wave plate QWP1, the light LGT passing through the second polarization layer can be right-handed circularly polarized (RCP), but in the present disclosure, for the sake of convenience, embodiments in which the light LGT passing through the second polarization layer is left-handed circularly polarized will be mainly described.

[0112] A material with isotropic refractive index can be filled between the first quarter-wave plate QWP1 and the second polarization layer POL2. In an embodiment, for example, air can be filled between the first quarter-wave plate QWP1 and the second polarization layer POL2.

[0113] The partial reflector layer HFM can be disposed on the first quarter-wave plate QWP1 with respect to a third direction DR3. The partial reflector layer HFM can be disposed adjacent to the first quarter-wave plate QWP1. The partial reflector layer HFM can be disposed between the first quarter-wave plate QWP1 and the output side A2. In some embodiments, the partial reflector layer HFM can be physically spaced apart from the first quarter-wave plate QWP1. The partial reflector layer HFM can not contact the first quarter-wave plate QWP1.

[0114] The partial reflector layer HFM can include a metal mirror coating or other mirror coatings such as a dielectric multilayer coating that is 50% transparent and 50% reflective on its surface.

[0115] At least a part of the first light L1 can pass through the partial reflector layer HFM to become a second light L2. The polarization states of the first light L1 and the second light L2 can be the same as each other.

[0116] A material with isotropic refractive index (or a material having isotropic refractive index) can be filled between the partial reflector layer HFM and the first quarter-wave plate QWP1. In an embodiment, for example, air can be filled between the partial reflector layer HFM and the first quarter-wave plate QWP1.

[0117] The second quarter-wave plate QWP2 can be disposed on the partial reflector layer HFM relative to the third direction DR3. The second quarter-wave plate QWP2 can be disposed adjacent to the partial reflector layer HFM. The second quarter-wave plate QWP2 can be disposed between the partial reflector layer HFM and the output side A2. In some embodiments, the second quarter-wave plate QWP2 can be physically spaced apart from the partial reflector layer HFM. The second quarter-wave plate QWP2 can be not in contact with the partial reflector layer HFM.

[0118] The second quarter-wave plate QWP2 can provide a phase difference of λ / 4 to vertically polarize the light LGT passing through the second polarization layer. The light LGT passing through the second polarization layer can be vertically polarized to become the third light L3. For example, when the light LGT passing through the second polarization layer is linearly polarized light at 0° with respect to the transmission axis of the first polarization layer POL1 and the transmission axis of the second polarization layer POL2, the light LGT passing through the second polarization layer can pass through the first quarter-wave plate QWP1 and the second quarter-wave plate QWP2 to be polarized into linearly polarized light at 90° with respect to the transmission axes of the first polarization layer POL1 and the second polarization layer POL2.

[0119] A refractive index isotropic material can be filled between the second quarter-wave plate QWP2 and the partial reflector layer HFM. In an embodiment, for example, air can be filled between the second quarter-wave plate QWP2 and the partial reflector layer HFM.

[0120] The third polarization layer POL3 can be disposed on the second quarter-wave plate QWP2 relative to the third direction DR3. The third polarization layer POL3 can be disposed adjacent to the output side A2. The third polarization layer POL3 can be disposed adjacent to the second quarter-wave plate QWP2. In some embodiments, the third polarization layer POL3 can be physically spaced apart from the second quarter-wave plate QWP2. The third polarization layer POL3 can be not in contact with the second quarter-wave plate QWP2.

[0121] A refractive index isotropic material can be filled between the third polarization layer POL3 and the second quarter-wave plate QWP2. In an embodiment, for example, air can be filled between the third polarization layer POL3 and the second quarter-wave plate QWP2.

[0122] The third polarization layer POL3 can have a transmission axis (or through axis) aligned along a predetermined direction. In an embodiment, for example, the third polarization layer POL3 can have a transmission axis aligned along the fourth direction DR4. The third polarization layer POL3 can be a reflective polarization layer. In an embodiment, for example, the third polarization layer POL3 can transmit only the component of light vibrating along the transmission axis of the third polarization layer POL3 and can reflect the remaining components of the light.

[0123] Thus, when the second polarized layer transmits light LGT which is linearly polarized light at 0° with respect to the transmission axes of the first polarized layer POL1 and the second polarized layer POL2, and the third light L3 is linearly polarized light at 90° with respect to the transmission axes of the first polarized layer POL1 and the second polarized layer POL2, the third light L3 can be reflected from the third polarized layer POL3 to become the fourth light L4.

[0124] The fourth light L4 can pass through the second quarter-wave plate QWP2 again to become the fifth light L5 which is right-handed circularly polarized. The right-handed circularly polarized fifth light L5 can be reflected from the partial mirror layer HFM. In this case, when circularly polarized light is reflected, the phase can change by 180°, and the right-handed circularly polarized fifth light L5 can be reflected from the partial mirror layer HFM to become the left-handed circularly polarized sixth light L6. The left-handed circularly polarized sixth light L6 can pass through the second quarter-wave plate QWP2 again to become the seventh light L7 which is linearly polarized light at 0° with respect to the transmission axes of the first polarized layer POL1 and the second polarized layer POL2.

[0125] As a result, the light LGT transmitted through the second polarized layer and the seventh light L7 can have the same polarization value or state, and the seventh light L7 can pass through the third polarized layer POL3.

[0126] In an embodiment, as described above, while the light emitted from the display panel DP passes through the second polarized layer POL2, the first quarter-wave plate QWP1, the partial mirror layer HFM, the second quarter-wave plate QWP2, and the third polarized layer POL3, the optical path can be folded, and the optical path can increase the distance between the third polarized layer POL3 and the partial mirror layer HFM. Therefore, compared with the case where the lens assembly OCP does not include the second polarized layer POL2, the first quarter-wave plate QWP1, the partial mirror layer HFM, the second quarter-wave plate QWP2, and the third polarized layer POL3, the lens assembly OCP can be formed closer to the focal point, and the thickness of the display device DD can be reduced.

[0127] Hereinafter, reference will be made to Figure 7 describe a lens assembly OCP' according to another embodiment. Figure 7 A schematic cross-sectional view of a lens assembly according to another embodiment is shown.

[0128] Except that the phase retardation layer RTHL' can be adhered (or joined) to the first polarized layer POL1 through the adhesive layer 101, Figure 7 the lens assembly OCP' shown in Figure 3The lens assembly OCP shown is substantially the same. However, the position of the phase retardation layer RTHL' is not limited thereto, and in some embodiments, the phase retardation layer RTHL' may be adhered to the lower portion of the second polarization layer POL2 through an adhesive layer 101. For ease of description, repeated detailed descriptions of elements that are the same as or similar to the above elements will be omitted or simplified.

[0129] In an embodiment, as Figure 7 shown, the phase retardation layer RTHL' may be adhered to (or coupled to) the first polarization layer POL1 through an adhesive layer 101 to form a phase retardation film attached to the first polarization layer POL1.

[0130] The adhesive layer 101 may include an optically isotropic material.

[0131] The adhesive layer 101 may include a flexible material. In some embodiments, the flexible material may include at least one selected from polyimide, polyethylene terephthalate, and polyethylene naphthalate.

[0132] The adhesive layer 101 may include at least one selected from a pressure-sensitive adhesive (PSA) and an optically clear adhesive (OCA). However, the present disclosure is not limited thereto.

[0133] Hereinafter, reference will be made to Figure 8 describe the lens assembly OCP” according to another embodiment. Figure 8 A schematic cross-sectional view of a lens assembly according to another embodiment is shown.

[0134] Except that the phase retardation layer RTHL” is directly disposed on the first polarization layer POL1, Figure 8 the lens assembly OCP” shown in Figure 3 is substantially the same as the lens assembly OCP shown in. However, the position of the phase retardation layer RTHL” is not limited thereto, and in some embodiments, the phase retardation layer RTHL” may be directly disposed below the second polarization layer POL2.

[0135] For ease of description, repeated detailed descriptions of elements that are the same as or similar to the above elements will be omitted or simplified.

[0136] In an embodiment, as Figure 8 shown, the phase retardation layer RTHL” may be directly disposed on the first polarization layer POL1 through a coating or deposition process.

[0137] In an embodiment, for example, the phase retardation layer RTHL” may be disposed by directly coating or depositing a material having a phase retardation value in the range of about 500 nm to about 1500 nm on the first polarization layer POL1.

[0138] The coating or deposition process can be carried out by methods commonly used in the art. In an embodiment, for example, one or more of coating processes such as spin coating, roll coating, bar coating, dip coating, gravure coating, curtain coating, die coating, spray coating, blade coating, and kneader coating can be used. In an embodiment, for example, one or more of deposition processes (such as chemical vapor deposition (CVD), physical vapor deposition (PVD), and plasma enhanced chemical vapor deposition (PECVD)) and printing processes (such as screen printing, spray printing, inkjet printing, offset printing, single-sheet printing, and lithographic printing) can be used.

[0139] Figure 9 and Figure 10 Schematically shows an embodiment of an electronic device to which the Figure 1 display device can be applied.

[0140] Referring to Figure 9 , an embodiment of the display device DD (see Figure 1 ) can be implemented as a head-mounted display 2000. The head-mounted display 2000 can be a wearable electronic device that can be worn on a user's head. The head-mounted display 2000 can include a head mounting band 2100 and a display device housing 2200.

[0141] The head mounting band 2100 can be connected to the display device housing 2200 to fix the display device housing 2200. As shown in Figure 9 , the head mounting band 2100 includes a horizontal band and a vertical band for fixing the head-mounted display 2000 to the user's head. The horizontal band can surround the side portion of the user's head, and the vertical band can surround the upper portion of the user's head. However, the present disclosure is not necessarily limited thereto, and the head mounting band 2100 can be implemented in the form of a spectacle frame or a helmet.

[0142] Referring to Figure 10 , an embodiment of the display device DD (see Figure 1 ) can be implemented as smart glasses 1000, which is another form of a head-mounted display. The smart glasses 1000 can include a frame 111 and a lens portion 112. The smart glasses 1000 is a wearable electronic device that can be worn on a user's face and can have a structure in which a part of the frame 111 is folded or unfolded. For example, the smart glasses 1000 can be a wearable device for augmented reality. However, the present disclosure is not limited thereto.

[0143] The frame 111 can include a housing 111b that supports the lens portion 112 and leg portions 111a for the user to wear. The leg portions 111a can be coupled to the housing 111b through hinges to be folded or unfolded.

[0144] A battery, a touchpad, a microphone, and / or a camera can be embedded in the frame 111. In addition, a projector that outputs light and / or a processor that controls optical signals, etc. can be embedded in the frame 111.

[0145] The lens part 112 can be an optical member that transmits or reflects light. The lens part 112 can include glass and / or transparent synthetic resin.

[0146] The display device DD can be applied to the lens part 112 of the smart glasses 1000. For example, the user can recognize an image displayed by an optical signal transmitted from the projector of the frame 111 through the lens part 112. For example, the user can recognize information such as time and date displayed in the lens part 112.

[0147] Figure 11 An embodiment of a head-mounted display worn on a user is schematically shown.

[0148] Referring to Figure 11 , a first display panel DP1 and a second display panel DP2 are provided in the head-mounted display 2000. The head-mounted display 2000 may further include one or more lenses LOCP and ROCP. The lenses LOCP and ROCP may correspond to the above-mentioned lens assembly OCP. Figure 11 The head-mounted display 2000 shown in Figure 9 may correspond to the embodiment shown in

[0149] In the display device housing 2200, the right-eye lens ROCP can be disposed between the first display panel DP1 and the user's right eye. In the display device housing 2200, the left-eye lens LOCP can be disposed between the second display panel DP2 and the user's left eye.

[0150] The image output from the first display panel DP1 can be displayed to the user's right eye through the right-eye lens ROCP. The right-eye lens ROCP can refract the light from the first display panel DP1 that is to be directed to the user's right eye. The right-eye lens ROCP can perform an optical function to adjust the viewing distance between the first display panel DP1 and the user's right eye.

[0151] The image output from the second display panel DP2 can be displayed to the user's left eye through the left-eye lens LOCP. The left-eye lens LOCP can refract the light from the second display panel DP2 that is to be directed to the user's left eye. The left-eye lens LOCP can perform an optical function to adjust the viewing distance between the second display panel DP2 and the user's left eye.

[0152] In an embodiment, each of the right-eye lens ROCP and the left-eye lens LOCP may include an optical lens having a flat cross-section. The optical lens having a flat cross-section may includeFigure 3 The second polarization layer POL2, the first quarter-wave plate QWP1, the partial mirror layer HFM, the second quarter-wave plate QWP2, and the third polarization layer POL3 shown in

[0153] In an embodiment, each of the right-eye lens ROCP and the left-eye lens LOCP may include a multi-channel lens including sub-regions having different optical characteristics. In such an embodiment, each display panel outputs an image corresponding to the sub-region of the multi-channel lens, and the output image may pass through the sub-region and be viewed by the user.

[0154] The present utility model should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the present utility model to those skilled in the art.

[0155] Although the present utility model has been specifically shown and described with reference to embodiments thereof, those of ordinary skill in the art will understand that various changes in form and detail may be made therein without departing from the spirit or scope of the present utility model as defined by the appended claims.

Claims

1. A lens assembly, comprising an incident side for light incidence and an exit side opposite to the incident side, characterized in that, The lens assembly includes: A first polarization layer disposed adjacent to the incident side; A second polarization layer disposed between the first polarization layer and the exit side; and A phase retardation layer disposed between the first polarization layer and the second polarization layer, wherein the phase retardation layer has a first phase retardation refractive index along a first direction, a second phase retardation refractive index equal to the first phase retardation refractive index along a second direction, and a third phase retardation refractive index along a third direction perpendicular to the first direction and the second direction, and wherein the first phase retardation refractive index and the second phase retardation refractive index are different from the third phase retardation refractive index.

2. The lens assembly according to claim 1, wherein The lens assembly further includes: A first quarter-wave plate disposed between the second polarization layer and the exit side; A partial mirror layer disposed between the first quarter-wave plate and the exit side; A second quarter-wave plate disposed between the partial mirror layer and the exit side; and A third polarization layer disposed adjacent to the exit side.

3. The lens assembly according to claim 1, wherein with respect to visible light, the phase retardation layer has a phase retardation value in the range of 500 nm to 1500 nm, wherein, the phase delay value of the phase delay layer is represented by R th and satisfies the following equation: R th = { ( N X + N Y ) / 2 - N Z} × d, wherein N X represents the first phase delay refractive index N Y represents the second phase delay refractive index N Z represents the third phase delay refractive index, and d represents the thickness of the phase retardation layer, [[ID= ​ ​ ​ ​ ​ ​ ​ ​ ​ 8. The lens assembly according to claim 7, wherein, ​ ​ ​ ​ ​ 10. A display device, characterized in that, ​ ​ ​

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