Near-eye display system

Abstract

A near-eye display system includes an image generating device, a polarization beam splitting element, and a first reflecting module. The image generating device is configured to provide an image light beam having a first polarization state. The polarization beam splitting element is configured to transmit the image light beam having the first polarization state to the first reflecting module. The first reflecting module is configured to reflect the image light beam having the first polarization state to form an image light beam having a second polarization state that is transmitted back to the polarization beam splitting element. The polarization beam splitting element is configured to transmit the image light beam having the second polarization state in a direction away from the image generating device. The near-eye display system can maintain a small size while extending the virtual image distance.

Description

Technical Field

[0001] This utility model relates to a display system, and more particularly to a near-eye display system. Background Technology

[0002] Traditional virtual reality (VR) display systems typically place a Fresnel magnifying lens in front of the display panel to create a virtual image. However, to increase the distance between the human eye and the virtual image, the object distance is set to be close to the lens focal length or a telephoto lens is used, according to the imaging formula. However, while magnifying the object distance can increase the distance between the human eye and the virtual image, it also increases the module depth, making it less portable and comfortable to wear. Using a short-focal-length Fresnel lens can save space, but it is prone to problems such as vignetting, stray light, and image distortion (such as scattering), as well as image quality degradation. In addition, while using aspherical or freeform lenses can improve image quality, their manufacturing complexity increases costs.

[0003] Virtual reality optical systems need to avoid vergence accommodation conflict (VAC) to reduce eye fatigue and dizziness. Related studies suggest that the distance between the human eye and the virtual image should be set at about 1.3 to 2.0 meters for comfort. If it is less than about 0.8 meters, it has deviated from the VAC comfort range and is prone to causing discomfort or visual fatigue. Therefore, it is necessary to increase the distance between the human eye and the virtual image to increase the wearing durability.

[0004] The "Background Art" paragraph is only used to help understand the content of this utility model. Therefore, the content disclosed in the "Background Art" paragraph may include some known technologies that are not known to those skilled in the art. The content disclosed in the "Background Art" paragraph does not mean that the content or the problems to be solved by one or more embodiments of this utility model were known or recognized by those skilled in the art prior to this application. Utility Model Content

[0005] This invention provides a near-eye display system that can extend the virtual image distance while maintaining a small size.

[0006] Other objects and advantages of this utility model can be further understood from the technical features disclosed herein.

[0007] To achieve one, some, or all of the above-mentioned objectives, or other objectives, one embodiment of the present invention provides a near-eye display system, including an image generating device, a polarizing beam splitter, and a first reflection module. The image generating device is used to provide an image beam having a first polarization state, wherein the image generating device is a liquid crystal display. The polarizing beam splitter is disposed on the optical path of the image beam having the first polarization state. The polarizing beam splitter is used to allow the image beam having the first polarization state to be transmitted to the first reflection module, and the first reflection module is used to reflect the image beam having the first polarization state to form an image beam having a second polarization state that is transmitted back to the polarizing beam splitter, wherein the polarizing beam splitter is used to allow the image beam having the second polarization state to be transmitted in a direction deviating from the image generating device.

[0008] Based on the above, the near-eye display system of this utility model has at least one of the following advantages: In the near-eye display system of this utility model, the optical path of the image beam is folded using a polarizing beam splitter and a first reflection module, so that the image beam is reflected by the first reflection module and transmitted back to the polarizing beam splitter, and finally transmitted out of the near-eye display system and to the user's eye. Therefore, the optical path length from the image generation device to the eye can be lengthened, allowing the near-eye display system of this utility model to extend the virtual image distance while maintaining a small size. Attached Figure Description

[0009] Figure 1 This is a cross-sectional schematic diagram of a near-eye display system according to an embodiment of the present invention.

[0010] Figure 2 This is a cross-sectional schematic diagram of a near-eye display system according to another embodiment of the present invention.

[0011] Figure 3 This is a cross-sectional schematic diagram of a near-eye display system according to another embodiment of the present invention.

[0012] Figure 4 This is a cross-sectional schematic diagram of a near-eye display system according to another embodiment of the present invention.

[0013] Figure 5 This is a cross-sectional schematic diagram of a near-eye display system according to another embodiment of the present invention.

[0014] Explanation of reference numerals in the attached figures: 50: Eyes 60: virtual image 100, 100a, 100b, 100c, 100d: Near-eye display system 110: Image generating device 111: Display Surface 112, 112a, 112b, 114, 114a, 114b, 116, 116a: Image beams 113: Light Emitting Diode Display Panel 115: Polarizing film 117: Third quarter-wave plate 120, 120a: Polarization beam splitter 121: Splitting surface 130, 130a, 130b: First reflection module 131, 141: Reflecting surfaces 132, 132b: First reflecting mirror 134, 134b: First quarter-wave plate 140, 140a: Second reflection module 142: Second reflecting mirror 144: Second quarter-wave plate 150: Lens A1: Optical axis D1: Virtual Image Distance DR: Suitable eye distance P1, P1', P1”: First polarization state P2, P2', P2”: Second polarization state Si: Image distance. Detailed Implementation

[0015] The foregoing description and other technical contents, features, and effects of this utility model will be clearly presented in the following detailed description of one of the preferred embodiments with reference to the accompanying drawings. The directional terms mentioned in the following embodiments, such as up, down, left, right, front, or back, are only for reference to the directions in the accompanying drawings. Therefore, the directional terms used are for illustrative purposes and not for limiting the scope of this utility model.

[0016] Figure 1 This is a cross-sectional schematic diagram of a near-eye display system according to an embodiment of the present invention. Please refer to... Figure 1The near-eye display system 100b of this embodiment includes an image generating device 110, a polarizing beam splitter 120, and a first reflection module 130b. The image generating device 110 is used to provide an image beam 112b having a first polarization state P1". In this embodiment, the image generating device 110 is, for example, a liquid crystal display, which can provide an image beam 112b having a first polarization state P1", wherein the first polarization state P1" is, for example, a linear polarization state. However, in other embodiments, the image generating device 110 may also be a light-emitting diode display panel with a polarizer disposed in front of it. The polarizer can filter the image beam 112b with natural light emitted by the light-emitting diode display panel into an image beam 112b having a first polarization state P1" (e.g., a linear polarization state), wherein the light-emitting diode display panel is, for example, a micro light-emitting diode display panel or an organic light-emitting diode display panel.

[0017] A polarizing beam splitter 120 is disposed on the optical path of an image beam 112b having a first polarization state P1”, and is used to transmit the image beam 112b having the first polarization state P1” to the first reflection module 130b. In this embodiment, the polarizing beam splitter 120 is used to reflect the image beam 112b having the first polarization state P1” to the first reflection module 130b. In this embodiment, the polarizing beam splitter 120 is, for example, a polarizing beam splitter (PBS) or a reflective brightness enhancement polarizing film, wherein the reflective brightness enhancement polarizing film is, for example, an APCF (Advanced Polarization Conversion Film) film or a DBEF (Dual Brightness Enhancement Film) film. The first polarization state P1” is, for example, an S polarization state for the polarizing beam splitter 120, therefore the image beam 112b having the first polarization state P1” as an S polarization state can be reflected by the polarizing beam splitter 120.

[0018] The first reflection module 130b is used to reflect the image beam 112b having a first polarization state P1” to form an image beam 114b having a second polarization state P2” that is transmitted back to the polarization beam splitter 120. The polarization beam splitter 120 is used to transmit the image beam 114b having the second polarization state P2” in a direction deviating from the image generating device 110, for example, to transmit the image beam 114b having the second polarization state P2” in a direction perpendicular to the transmission direction of the image beam 112b having the first polarization state P1”. In this embodiment, the polarization beam splitter 120 is used to allow the image beam 114b having the second polarization state P” to pass through and be transmitted out of the near-eye display system 100b in a direction perpendicular to the transmission direction of the image beam 112b having the first polarization state P1”, for example, to the user's eye 50.

[0019] In this embodiment, the first reflection module 130 includes a first reflector 132b and a first quarter-wave plate 134b. The first reflector 132b is disposed on the optical path of the image beams 112b and 114b, and the first quarter-wave plate 134b is disposed on the optical path of the image beams 112b and 114b between the polarization beam splitter 120 and the first reflector 132b. In this embodiment, the second polarization state P2” is, for example, a P-polarization state for the polarization beam splitter 120. This is because the image beam 112b with the first polarization state P1” from the polarization beam splitter 120 first passes through the first quarter-wave plate 134b. At this time, the image beam 112b with the first polarization state P1” is transformed into an image beam 112b with a single rotation direction of circular polarization (e.g., left-hand circular polarization or right-hand circular polarization). When this image beam 112b with a single rotation direction of circular polarization is reflected by the first mirror 132b into an image beam 114b, the image beam 114b will have the same polarization state as the image beam 114b. If the image beam 112b has a circularly polarized state with opposite rotation, for example, if the image beam 112b has a right-handed circularly polarized state, then the image beam 114b will have a left-handed circularly polarized state. Furthermore, the image beam 114b will pass through the first quarter-wave plate 134b again, so the polarization state of the image beam 114b passing through the first quarter-wave plate 134b will change to a second polarization state P2”, where the second polarization state P2” is a linear polarization state, for example, a P-polarization state. Therefore, the image beam 114b with the second polarization state P2” transmitted back to the polarization beam splitter 120 will have a P-polarization state and penetrate the polarization beam splitter 120, thus reaching the user's eye 50. In this way, the eye 50 can see a virtual image 60 corresponding to the image displayed by the image generating device 110 through the near-eye display system 100b.

[0020] In the near-eye display system 100b of this embodiment, the optical paths of image beams 112b and 114b are folded using a polarizing beam splitter 120 and a first reflection module 130b. This causes the image beams 112b and 114b to be reflected back to the polarizing beam splitter 120 by the first reflection module 130b, and finally pass through the polarizing beam splitter 120 to exit the near-eye display system 100b and reach the user's eye 50. Therefore, the optical path length from the image generating device 110 to the eye 50 can be lengthened, allowing the near-eye display system 100 of this embodiment to extend the virtual image distance D1 (i.e., the distance from the eye 50 to the virtual image 60) while maintaining a small size. This also effectively improves the problem of visual convergence-accommodation conflict.

[0021] In this embodiment, the near-eye display system 100b further includes at least one lens 150 (in... Figure 1In this embodiment, two lenses 150 are used as an example, but in other embodiments, only one lens 150 may be used. Lens 150 is positioned on the optical path of the image beam 114b that exits the near-eye display system 100b. For example, lens 150 is positioned on the optical path of the image beam 114b between the eye 50 and the polarizing beam splitter 120. In this embodiment, lens 150 has positive diopter, thus allowing it to elongate the virtual image distance D1. In this embodiment, lens 150 can be a general spherical lens or an aspherical lens. However, in other embodiments, lens 150 can also be a Fresnel lens or a freeform lens. Furthermore, in this embodiment, the first reflecting mirror 132b can be a concave mirror, which further increases the virtual image distance D1. However, in other embodiments, the first reflecting mirror 132b can also be a plane mirror.

[0022] Figure 2 This is a cross-sectional schematic diagram of a near-eye display system according to another embodiment of the present invention. Please refer to... Figure 2 The near-eye display system 100c of this embodiment and Figure 1 Similar to the near-eye display system 100b, the main differences between the two are as follows. In the near-eye display system 100c of this embodiment, the polarization beam splitter 120 is used to allow an image beam 112 having a first polarization state P1 to pass through and be transmitted to the first reflection module 130b, and to reflect an image beam 114 having a second polarization state P2 and transmit it out of the near-eye display system 100c. In this embodiment, the first polarization state P1 is, for example, a P-polarization state for the polarization beam splitter 120, and the second polarization state P2 is, for example, an S-polarization state for the polarization beam splitter 120.

[0023] In this embodiment, the first reflecting mirror 132b is, for example, a concave mirror. However, in other embodiments, the first reflecting mirror 132b may also be a plane mirror.

[0024] In this embodiment, the polarization beam splitter 120 is used to reflect the image beam 114 having a second polarization state P2 and transmit it out of the near-eye display system 100b in a direction perpendicular to the transmission direction of the image beam 112 having a first polarization state P1, for example, to the user's eye 50.

[0025] Figure 3 This is a cross-sectional schematic diagram of a near-eye display system according to another embodiment of the present invention. Please refer to... Figure 3 The near-eye display system 100d in this embodiment and Figure 1 Similar to the near-eye display system 100b, the main differences between the two are as follows. In the near-eye display system 100d of this embodiment, the first reflecting mirror 132 of the first reflecting module 130 is a plane mirror, and the first quarter-wave plate 134 of the first reflecting module 130 is flat. Similarly, if Figure 2 If the first reflecting mirror 132 of the first reflecting module 130 is a plane mirror, then the first quarter-wave plate 134 of the first reflecting module 130 is flat. In contrast, in Figure 1 In the near-eye display system 100b, the first reflecting mirror 132b of the first reflecting module 130b should be a concave mirror, and the first quarter-wave plate 134b of the first reflecting module 130b is also curved along with the concave mirror. Similarly, in Figure 2 In the near-eye display system 100c, the first reflecting mirror 132b of the first reflecting module 130b should be a concave mirror, and the first quarter-wave plate 134b of the first reflecting module 130b is also curved along with the concave mirror.

[0026] Figure 4 This is a cross-sectional schematic diagram of a near-eye display system according to another embodiment of the present invention. Please refer to... Figure 4 The near-eye display system 100 of this embodiment includes an image generating device 110, a polarizing beam splitter 120, a first reflection module 130, and a second reflection module 140. The image generating device 110 is used to provide an image beam 112 having a first polarization state P1. In this embodiment, the image generating device 110 is, for example, a liquid crystal display panel, which can provide an image beam 112 having a first polarization state P1, wherein the first polarization state P1 is, for example, a linear polarization state. However, in other embodiments, the image generating device 110 may also be a light-emitting diode display panel with a polarizer disposed in front of it. The polarizer can filter the image beam 112 with natural light emitted by the light-emitting diode display panel into an image beam 112 having a first polarization state P1 (e.g., a linear polarization state), wherein the light-emitting diode display panel is, for example, a micro light-emitting diode display panel or an organic light-emitting diode display panel.

[0027] A polarizing beam splitter 120 is disposed in the optical path of an image beam 112 having a first polarization state P1, and is used to allow the image beam 112 having the first polarization state P1 to pass through. In this embodiment, the polarizing beam splitter 120 is, for example, a polarizing beam splitter (PBS) or a reflective brightness enhancement polarizing film, wherein the reflective brightness enhancement polarizing film is, for example, an APCF (Advanced Polarization Conversion Film) film or a DBEF (Dual Brightness Enhancement Film) film. The first polarization state P1 is, for example, a P-polarized state with respect to the polarizing beam splitter 120, therefore the image beam 112 having the first polarization state P1 as a P-polarized state can pass through the polarizing beam splitter 120.

[0028] The first reflection module 130 is disposed on the optical path of the image beam 112 having a first polarization state P1 that passes through the polarization beam splitter 120, and is used to reflect the image beam 112 having the first polarization state P1 to form an image beam 114 having a second polarization state P2 that is transmitted back to the polarization beam splitter 120, wherein the polarization beam splitter 120 is used to reflect the image beam 114 having the second polarization state P2. In this embodiment, the first reflection module 130 includes a first reflector 132 and a first quarter-wave plate 134. The first reflector 132 is disposed on the optical path of the image beam 114, and the first quarter-wave plate 134 is disposed on the optical path of the image beams 112 and 114 between the polarization beam splitter 120 and the first reflector 132. In this embodiment, the second polarization state P2 is, for example, an S-polarization state for the polarization beam splitter 120. This is because the image beam 112 from the polarization beam splitter 120 with the first polarization state P1 first passes through the first quarter-wave plate 134. At this time, the image beam 112 with the first polarization state P1 is transformed into an image beam 112 with a single rotation direction of circular polarization (e.g., left-handed or right-handed circular polarization). When this image beam 112 with a single rotation direction of circular polarization is reflected by the first mirror 132 into an image beam 114, the image beam 114... The image beam 114 will have a circular polarization state with the opposite rotation direction to the image beam 112. For example, if the image beam 112 has a left-hand circular polarization state, then the image beam 114 will have a right-hand circular polarization state. The image beam 114 will pass through the first quarter-wave plate 134 again. Therefore, the polarization state of the image beam 114 passing through the first quarter-wave plate 134 will change to a second polarization state P2. The second polarization state P2 is a linear polarization state, for example, an S-polarization state. Therefore, the image beam 114 with the second polarization state P2 that is transmitted back to the polarization beam splitter 120 will have an S-polarization state and be reflected by the polarization beam splitter 120.

[0029] The second reflection module 140 is disposed on the optical path of the image beam 114 having a second polarization state P2 reflected by the polarization beam splitter 120, and is used to reflect the image beam 114 having a second polarization state P2 to form an image beam 116 having a first polarization state P1 that is transmitted back to the polarization beam splitter 120. The polarization beam splitter 120 is used to allow the image beam 116 having a first polarization state P1 to pass through and be transmitted out of the near-eye display system 100 in a transmission direction perpendicular to the image beam 112 having a first polarization state P1, for example, to the user's eye 50.

[0030] In this embodiment, the second reflection module 140 includes a second reflector 142 and a second quarter-wave plate 144. The second reflector 142 is disposed on the optical path of the image beams 114 and 116, and the second quarter-wave plate 144 is disposed on the optical path of the image beams 114 and 116 between the polarization beam splitter 120 and the second reflector 142. The image beam 114 with a second polarization state P2 from the polarization beam splitter 120 first passes through the second quarter-wave plate 144. At this time, the image beam 112 with the second polarization state P2 is transformed into an image beam 114 with a single rotation direction of circular polarization. When this image beam 114 with a single rotation direction of circular polarization is reflected by the second mirror 142 into an image beam 116, the image beam 116 will have a circular polarization state with the opposite rotation direction to the image beam 112. The image beam 116 will then pass through the second quarter-wave plate 144 again. Therefore, the polarization state of the image beam 116 passing through the second quarter-wave plate 144 will be transformed into a first polarization state P1. The first polarization state P1 is, for example, a P-polarization state. Therefore, the image beam 116 with the first polarization state P1 transmitted back to the polarization beam splitter 120 will have a P-polarization state and can penetrate the polarization beam splitter 120 and be transmitted to the user's eye 50. In this way, the eye 50 can see a virtual image 60 in front of it that corresponds to the image displayed by the image generating device 110 through the near-eye display system 100.

[0031] In the near-eye display system 100 of this embodiment, the optical paths of image beams 112, 114, and 116 are folded using a polarizing beam splitter 120, a first reflection module 130, and a second reflection module 140. This allows image beams 112 and 114 to be sequentially reflected by the first reflection module 130 and the second reflection module 140, returning to the polarizing beam splitter 120, and finally passing through the polarizing beam splitter 120 to exit the near-eye display system 100 and reach the user's eye 50. Therefore, the optical path length from the image generating device 110 to the eye 50 can be lengthened, enabling the near-eye display system 100 of this embodiment to extend the virtual image distance D1 (i.e., the distance from the eye 50 to the virtual image 60) while maintaining a small size. This also effectively improves the problem of visual convergence-accommodation conflict.

[0032] In this embodiment, the near-eye display system 100 further includes a lens 150, which is disposed on the optical path of the image light beam 116 exiting the near-eye display system 100. The lens 150 is, for example, disposed on the optical path of the image light beam 116 between the eye 50 and the polarization beam splitter 120. In this embodiment, the lens 150 has positive diopter, such that the lens 150 can be used to extend the virtual image distance D1. In one embodiment, the distance of the virtual image 60 of the image generating device 110 seen by the eye 50 through the lens 150 (i.e., the virtual image distance D1) falls within the range of 0.8 to 2.0 meters. In this embodiment, the lens 150 is a Fresnel lens. However, in other embodiments, the lens 150 may also be an aspheric lens or a free-form surface lens.

[0033] The imaging formula followed by the lens 150 is as follows: 1 / So + 1 / Si = 1 / f Equation (1) Wherein, f is the focal length of the lens 150, So is the object distance, and Si is the image distance. At a fixed focal length, if the virtual image distance D1 needs to be increased, the object distance is required to be closer to the focal length of the lens 150, so a longer virtual image distance D1 can be obtained by increasing the object distance, and the virtual image magnification effect can be achieved only under the condition of So<f. The virtual image distance D1 is equal to the image distance Si between the lens 150 and the virtual image 60 plus the eye relief DR, wherein the eye relief DR is the distance from the eye 50 to the lens 150. In this embodiment, the method of folding the image light beams 112, 114, and 116 twice can effectively increase the object distance, make the object distance close to the focal length of the lens 150, and further effectively extend the virtual image distance D1, so that the virtual image distance D1 reaches 0.8 to 2.0 meters. In addition, the near-eye display system 100 of this embodiment has high integrated optical efficiency, good optical path efficiency, easy assembly, low cost, and can effectively improve display comfort and eye use stability. When a Fresnel lens is used as the lens 150, the thickness and material amount of the lens can be greatly reduced, and the volume, weight and cost of the near-eye display system 100 can be further effectively reduced.

[0034] In this embodiment, the optical axis A1 of the lens 150 is parallel to the image generating device 110 and the first reflection module 130, and is perpendicular to the second reflection module 140. Specifically, the optical axis A1 is parallel to the display surface 111 of the image generating device 110 and the reflection surface 131 of the first reflection module 130, and is perpendicular to the reflection surface 141 of the second reflection module 140. In this embodiment, the polarization beam splitter 120 is inclined by 45 degrees relative to the optical axis A1 of the lens 150. Specifically, the beam splitting surface 121 of the polarization beam splitter 120 is inclined by 45 degrees relative to the optical axis A1.

[0035] In this embodiment, the image generating device 110 and the second reflection module 140 are arranged at a 90-degree angle, the second reflection module 140 and the first reflection module 130 are arranged at a 90-degree angle, and the image generating device 110 and the first reflection module 130 are arranged parallel to each other on opposite sides of the polarization beam splitter 120. Specifically, the display surface 111 of the image generating device 110 and the reflective surface 141 of the second reflection module 140 are arranged at a 90-degree angle, the reflective surface 141 of the second reflection module 140 and the reflective surface 131 of the first reflection module 130 are arranged at a 90-degree angle, and the display surface 111 of the image generating device 110 and the reflective surface 131 of the first reflection module 130 are arranged parallel to each other on opposite sides of the polarization beam splitter 120. In this embodiment, the polarization beam splitter 120 is tilted at a 45-degree angle relative to the image generating device 110, the first reflection module 130 and the second reflection module 140. Specifically, the beam-splitting surface 121 of the polarization beam-splitting element 120 is tilted at 45 degrees relative to the display surface 111 of the image generating device 110, the reflective surface 131 of the first reflective module 130, and the reflective surface 141 of the second reflective module 140.

[0036] Figure 5 This is a cross-sectional schematic diagram of a near-eye display system according to another embodiment of the present invention. The near-eye display system 100a of this embodiment is... Figure 4 Similar to the near-eye display system 100, the main differences between the two are as follows. In the near-eye display system 100a of this embodiment, the first reflecting module 130a is a first reflecting mirror, and the second reflecting module 140a is a second reflecting mirror. In this embodiment, neither the first reflecting module 130a nor the second reflecting module 140a has a quarter-wave plate. One of the first polarization state P1' and the second polarization state P2' is a left-handed circularly polarized state, and the other of the first polarization state P1' and the second polarization state P2' is a right-handed circularly polarized state. Furthermore, the polarization beam splitter 120a is, for example, a cholesteric liquid crystal layer, and the following uses a left-handed cholesteric liquid crystal layer as an example.

[0037] In this embodiment, the image generation apparatus 110a includes a light-emitting diode (LED) display panel 113, a polarizer 115, and a third quarter-wave plate 117. The third quarter-wave plate 117 is disposed between the polarization beam splitter 120a and the LED display panel 113, and the polarizer 115 is disposed between the third quarter-wave plate 117 and the LED display panel 113. In this way, the polarizer 115 can first filter the image beam with natural light emitted from the LED display panel 113 into an image beam with a linear polarization state, and then the third quarter-wave plate 117 converts the linearly polarized image beam into an image beam 112a with a circular polarization state (i.e., a first polarization state P1'). In this example, the image beam 112a has a right-hand circular polarization state. In this embodiment, the LED display panel 113 is, for example, a miniature LED display panel or an organic light-emitting diode (OLED) display panel.

[0038] Since the polarizing beam splitter 120a is a left-handed cholesteric liquid crystal layer in this example, it allows the image beam 112a with a right-handed circular polarization state (i.e., the first polarization state P1') to pass through and be transmitted to the first reflection module 130a (i.e., the first reflector). The first reflection module 130a reflects the image beam 112a to form an image beam 114a with a left-handed circular polarization state (i.e., the second polarization state P2'). Since the polarizing beam splitter 120a is a left-handed cholesteric liquid crystal layer in this example, it reflects the image beam 114a with a left-handed circular polarization state (i.e., the second polarization state P2') to the second reflection module 140a (i.e., the second reflector). The second reflection module 140a reflects the image beam 114a with a left-handed circular polarization state (i.e., the second polarization state P2') into an image beam 116a with a right-handed circular polarization state (i.e., the first polarization state P1'). Since the polarization beam splitter 120a is a left-handed cholesterol liquid crystal layer in this example, it allows the image beam 116a with a right-handed circular polarization state (i.e., the first polarization state P1') to pass through. The image beam 116a after passing through the polarization beam splitter 120a will be transmitted in a direction perpendicular to the transmission direction of the image beam 112a with the first polarization state P1' and will be transmitted sequentially to the lens 150 and the eye 50.

[0039] In another embodiment, a liquid crystal display panel can be used instead of a light-emitting diode display panel 113. Since the light emitted by the liquid crystal display panel is linearly polarized light, the polarizer 115 can be omitted, and only a third quarter-wave plate 117 disposed between the polarizing beam splitter 120a and the liquid crystal display panel can be used.

[0040] In summary, the near-eye display system of this invention has at least one of the following advantages: In the near-eye display system of this invention, a polarizing beam splitter and a first reflection module are used to fold the optical path of the image beam, so that the image beam is reflected by the first reflection module and transmitted back to the polarizing beam splitter, and finally transmitted out of the near-eye display system and to the user's eye. Therefore, the optical path length from the image generation device to the eye can be lengthened, allowing the near-eye display system of this invention to extend the virtual image distance while maintaining a small size.

[0041] The above description is merely a preferred embodiment of this utility model and should not be construed as limiting the scope of this utility model. Any simple equivalent changes and modifications made in accordance with the claims and content of this utility model shall still fall within the scope of this utility model patent. Furthermore, no embodiment or claim of this utility model needs to achieve all the objectives, advantages, or features disclosed in this utility model. In addition, the abstract and title of the utility model are only used to assist in patent document retrieval and are not intended to limit the scope of this utility model. Furthermore, the terms "first," "second," etc., mentioned in this specification or claims are only used to name elements or distinguish different embodiments or scopes, and are not used to limit the upper or lower limit of the number of elements.

Claims

1. A near-eye display system, characterized in that, The near-eye display system includes an image generation device, a polarization beam splitter, and a first reflection module, wherein: The image generating device is used to provide an image beam having a first polarization state, wherein the image generating device is a liquid crystal display; The polarization beam splitter is disposed on the optical path of the image beam having the first polarization state; and The polarization beam splitter is used to transmit the image beam having the first polarization state to the first reflection module, and the first reflection module is used to reflect the image beam having the first polarization state to form an image beam having the second polarization state that is transmitted back to the polarization beam splitter, wherein the polarization beam splitter is used to transmit the image beam having the second polarization state in a direction away from the image generating device.

2. The near-eye display system according to claim 1, characterized in that, The polarization beam splitter is used to reflect the image beam having the first polarization state to the first reflection module, and to allow the image beam having the second polarization state to pass through and be transmitted out of the near-eye display system.

3. The near-eye display system according to claim 1, characterized in that, The polarization beam splitter is used to allow the image beam with the first polarization state to pass through and be transmitted to the first reflection module, and to reflect the image beam with the second polarization state and transmit it out of the near-eye display system.

4. The near-eye display system according to claim 1, characterized in that, The first reflection module includes: A first reflecting mirror is disposed on the optical path of the image beam; and A first quarter-wave plate is disposed on the optical path of the image beam between the polarizing beam splitter and the first reflector.

5. The near-eye display system according to claim 1, characterized in that, The near-eye display system also includes a lens disposed on the optical path through which the image beam of the near-eye display system is transmitted.

6. The near-eye display system according to claim 5, characterized in that, The lens is a Fresnel lens.

7. The near-eye display system according to claim 5, characterized in that, The lens is an aspherical lens or a freeform lens.

8. The near-eye display system according to claim 5, characterized in that, The lens has positive diopter.

9. The near-eye display system according to claim 1, characterized in that, The polarizing beam splitter allows the image beam having the first polarization state to pass through, and the polarizing beam splitter also reflects the image beam having the second polarization state. The near-eye display system further includes a second reflection module disposed on the optical path of the image beam having the second polarization state reflected by the polarizing beam splitter, and used to reflect the image beam having the second polarization state to form an image beam having the first polarization state that is transmitted back to the polarizing beam splitter. The polarizing beam splitter allows the image beam having the first polarization state that is transmitted back to the polarizing beam splitter to pass through and exit the near-eye display system.

10. The near-eye display system according to claim 9, characterized in that, The near-eye display system further includes a lens disposed on the optical path through which the image beam of the near-eye display system is transmitted, wherein the optical axis of the lens is parallel to the image generating device and the first reflection module, and perpendicular to the second reflection module.

11. The near-eye display system according to claim 10, characterized in that, The polarizing beam splitter is tilted at 45 degrees relative to the optical axis of the lens.

12. The near-eye display system according to claim 9, characterized in that, The near-eye display system further includes a lens disposed on the optical path through which the image beam of the near-eye display system is transmitted, wherein the distance at which the eye sees the virtual image of the image generating device through the lens falls within the range of 0.8 to 2.0 meters.

13. The near-eye display system according to claim 9, characterized in that, The first reflection module includes: A first reflecting mirror is disposed on the optical path of the image beam; and A first quarter-wave plate is disposed on the optical path of the image beam between the polarizing beam splitter and the first reflector, and The second reflection module includes: A second reflecting mirror is disposed in the optical path of the image beam; and A second quarter-wave plate is disposed on the optical path of the image beam between the polarizing beam splitter and the second reflector, wherein the first polarization state is a P-polarization state and the second polarization state is an S-polarization state.

14. The near-eye display system according to claim 13, characterized in that, The polarization beam splitter is a polarization beam splitter or a reflective brightness enhancement polarizing film.

15. The near-eye display system according to claim 9, characterized in that, The first reflection module is a first reflector, the second reflection module is a second reflector, one of the first polarization state and the second polarization state is a left-handed circular polarization state, and the other of the first polarization state and the second polarization state is a right-handed circular polarization state.

16. The near-eye display system according to claim 15, characterized in that, The polarization beam splitter is a cholesterol liquid crystal layer.

17. The near-eye display system according to claim 9, characterized in that, The image generating apparatus includes a liquid crystal display panel and a third quarter-wave plate, wherein the third quarter-wave plate is disposed between the polarizing beam splitter and the liquid crystal display panel.

18. The near-eye display system according to claim 9, characterized in that, The image generating device is configured at a 90-degree angle to the second reflection module, and the second reflection module is configured at a 90-degree angle to the first reflection module. The image generating device and the first reflection module are configured parallel to each other on opposite sides of the polarization beam splitter.

19. The near-eye display system according to claim 18, characterized in that, The polarization beam splitter is tilted at 45 degrees relative to the image generating device, the first reflection module, and the second reflection module.

20. The near-eye display system according to claim 1, characterized in that, The polarization beam splitter is used to propagate the image beam having the second polarization state in a direction perpendicular to the propagation direction of the image beam having the first polarization state.

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