Variable focus lens element, corrective lens assembly, and optical display system

Abstract

The present application provides a variable focus lens element, a corrective lens assembly and an optical display system. The variable focus lens element comprises a lens unit and a polarization controller. The lens unit has different optical powers for light beams with different polarization directions. When a light beam is introduced into the variable focus lens element via the polarization controller in a first state, the polarization direction of the light beam is converted by the polarization controller. When the light beam is introduced into the variable focus lens element via the polarization controller in a second state, the polarization direction of the light beam is prevented from being converted by the polarization controller.

Description

Technical Field

[0001] The present invention relates to a variable focus lens element, and more particularly to a variable focus lens element, a corrective lens assembly having at least one variable focus lens element, and an optical display system having at least one variable focus lens element. Background Technology

[0002] Near-eye displays (e.g., head-mounted displays) are frequently used in systems such as Virtual Reality (VR) and Augmented Reality (AR) to create virtual images within the user's field of view (FOV). However, due to the phenomenon of vergence-accommodation conflict (VAC), users using near-eye displays cannot easily estimate the relative distance of objects by simultaneously performing convergence and accommodation with both eyes, which can easily lead to visual fatigue or eye strain.

[0003] To provide a better field of view, the distance between the near-eye display and the user's eyes is typically limited to a specific range (e.g., 15mm to 25mm). However, if the user wears glasses, the distance between their eyes and the near-eye display cannot be maintained within this specific range, which is detrimental to the presentation of the field of view. Furthermore, providing the user with additional special glasses for viewing images would cause inconvenience. Summary of the Invention

[0004] The object of the present invention is to provide a variable focal length lens element suitable for optical display systems (e.g., near-eye displays) to eliminate or mitigate at least one of the aforementioned disadvantages.

[0005] The present invention relates to a variable focus lens element, comprising a lens unit and a polarization controller.

[0006] The lens unit includes a polarization-dependent lens and has different optical powers for beams with different polarization directions.

[0007] The polarization controller is coupled to the lens unit and can be switched from a first state to a second state via an electrically driven method.

[0008] Specifically, when the light beam is introduced into the variable focus lens element along the optical axis in the Z direction and passes through the polarization controller in the first state, the polarization direction of the light beam will be changed by the polarization controller. When the light beam is introduced into the variable focus lens element along the optical axis and passes through the polarization controller in the second state, the polarization direction of the light beam can be prevented from being changed by the polarization controller.

[0009] Preferably, in the variable focus lens element of the present invention, the lens unit further includes a polarization-independent lens.

[0010] Preferably, in the variable focus lens element of the present invention, the polarization-dependent lens and the polarization-independent lens each have two surfaces, and the two surfaces are selected from one of a plane, a spherical surface, an aspherical surface, a freeform surface, a concave surface, and a convex surface.

[0011] Preferably, in the variable focus lens element of the present invention, the polarization controller is selected from twisted nematic liquid crystal elements, liquid crystal waveplates, and combinations thereof.

[0012] Preferably, in the variable focus lens element of the present invention, the polarization-dependent lens has a plurality of liquid crystal molecules whose long axes are arranged along a Y direction orthogonal to the Z direction. When a light beam polarized along an X direction orthogonal to the Y direction and the Z direction passes through the lens unit, the lens unit has a first optical power. When a light beam polarized along the Y direction passes through the lens unit, the lens unit has a second optical power different from the first optical power.

[0013] Another object of the present invention is to provide a corrective lens assembly.

[0014] The corrective lens assembly of the present invention includes at least one variable focus lens element and a polarizer as described above.

[0015] The polarizer is used to transmit linearly polarized light to the at least one variable focus lens element, and the polarization controller and lens unit of the at least one variable focus lens element are respectively arranged in a manner close to and far from the polarizer.

[0016] Another object of the present invention is to provide an optical display system.

[0017] The optical display system of the present invention includes at least one variable focus lens element as described above.

[0018] Preferably, the optical display system of the present invention further includes a display for providing a light beam through the at least one variable focus lens element, wherein the polarization controller and lens unit of the at least one variable focus lens element are respectively arranged in a manner adjacent to and distant from the display.

[0019] Preferably, the optical display system of the present invention further includes a polarizer disposed between the display and the at least one variable focus lens element.

[0020] Preferably, the optical display system of the present invention further includes a fixed-focus lens disposed downstream of the display, the fixed-focus lens being used to transmit a light beam from the display to a viewer via the fixed-focus lens and the at least one variable-focus lens element.

[0021] Preferably, the optical display system of the present invention further includes a beam splitter for combining a beam from a real object and a beam from the display and output by the at least one variable focus lens element.

[0022] Preferably, in the optical display system of the present invention, the beam splitter is a polarization-independent beam splitter.

[0023] Preferably, in the optical display system of the present invention, the beam splitter is used to partially transmit a light beam from a real object located in front of the beam splitter, and the display is disposed to the left or right of the beam splitter.

[0024] Preferably, in the optical display system of the present invention, the at least one variable focus lens element is disposed between the beam splitter and the display.

[0025] Preferably, the optical display system of the present invention further includes a fixed-focus lens for guiding the light beam from the display to the beam splitter via the at least one variable-focus lens element and the fixed-focus lens.

[0026] Preferably, in the optical display system of the present invention, the beam splitter is located between the at least one variable focus lens element and the display, and the optical display system further includes a fixed focus lens disposed outside the at least one variable focus lens element, so that the light beam from the display and passing through the beam splitter can be reflected back to the beam splitter by the fixed focus lens.

[0027] Preferably, the optical display system of the present invention further includes an augmented reality element, the augmented reality element being used to direct a combined image from the augmented reality element to a viewer via the at least one zoom lens element.

[0028] Preferably, the optical display system of the present invention further includes a polarizer disposed between the augmented reality element and the at least one variable focus lens element, the polarizer being used to convert the light beam from the combined image into linearly polarized light so as to pass through the at least one variable focus lens element.

[0029] The beneficial effects of the present invention are as follows: the at least one variable focus lens element changes the polarization direction of the light beam by switching the state of its polarization controller, thereby giving the lens unit different optical powers. The corrective lens assembly can have a variety of possible optical power changes by switching the state of its at least one variable focus lens element, which is suitable for daily vision correction. Similarly, the optical display system can move the formation position of the generated virtual image according to the viewer's distance requirements by switching the state of its at least one variable focus lens element, thereby mitigating the visual convergence-accommodation conflict caused by near-eye displays. Attached Figure Description

[0030] Figure 1 This is a schematic diagram illustrating an embodiment of the variable focus lens element of the present invention, with its polarization controller in a first state;

[0031] Figure 2 This is a diagram, for illustrative purposes only. Figure 1 This indicates that the polarization controller in the described embodiment is in a second state;

[0032] Figure 3 This is a schematic diagram illustrating a first embodiment of the corrective lens assembly of the present invention;

[0033] Figure 4 This is a schematic diagram illustrating a second embodiment of the corrective lens assembly of the present invention;

[0034] Figures 5 to 7 It is similar to Figure 4 The schematic diagram illustrates that the second embodiment of the corrective lens assembly is in another implementation state;

[0035] Figure 8 This is a schematic diagram illustrating a first embodiment of the optical display system of the present invention;

[0036] Figure 9 This is a diagram, for illustrative purposes only. Figure 8 This indicates that the optical display system is in another embodiment.

[0037] Figure 10 This is a schematic diagram illustrating a second embodiment of the optical display system of the present invention;

[0038] Figures 11 to 13 It is similar to Figure 10 The schematic diagram illustrates that the second embodiment of the optical display system is in another implementation state;

[0039] Figure 14 This is a schematic diagram illustrating a third embodiment of the optical display system of the present invention;

[0040] Figure 15 This is a diagram, for illustrative purposes only. Figure 14 This indicates that the third embodiment of the optical display system is in another implementation state;

[0041] Figure 16 This is a schematic diagram illustrating a fourth embodiment of the optical display system of the present invention, and indicating the optical path used to form a virtual image;

[0042] Figure 17 This is a schematic diagram illustrating the fourth embodiment of the optical display system, and indicating the optical path used to form an image of a real object; and

[0043] Figure 18 This is a schematic diagram illustrating the fifth embodiment of the optical display system described in this invention. Detailed Implementation

[0044] Before the present invention is described in detail, it should be noted that similar elements are represented by the same numbers in the following description. The relevant technical content, features, and effects of the present invention will be clearly presented in the following detailed description of embodiments with reference to the accompanying drawings. Furthermore, it should be noted that the drawings of the present invention are only for illustrating the structural and / or positional relationships between elements and are not related to the actual dimensions of each element. The directional terms used in the description and scope of the application (e.g., front, back, left, right, top, bottom, etc.) are intended only to help describe the content and should not be considered as limitations of the present invention in any way.

[0045] See Figure 1 and Figure 2 This is an embodiment of the variable focus lens element 10 of the present invention, which includes a lens unit 20 and a polarization controller 30.

[0046] The lens unit 20 includes a polarization-dependent lens 21, which has different optical powers for beams with different polarization directions. In some embodiments, the lens unit 20 further includes a polarization-independent lens 22, and the polarization-dependent lens 21 and the polarization-independent lens 22 each have two surfaces that are opposite to each other to determine their optical properties, and the two surfaces are selected from one of a plane, a sphere, an aspherical surface, a freeform surface, a concave surface, and a convex surface.

[0047] In this embodiment, one of the polarization-dependent lens 21 and the polarization-independent lens 22 is a plano-concave lens, and the other is a plano-convex lens. Figure 1and Figure 2 The variable focus lens element 10 shown is illustrated using the example of the polarization-dependent lens 21 being a plano-concave lens and the polarization-independent lens 22 being a plano-convex lens.

[0048] In some embodiments, the polarization-dependent lens 21 has a plurality of liquid crystal molecules 211, the major axis L of which is arranged along a Y direction orthogonal to the Z direction. A light beam is guided and passes through the variable focus lens element 10, and is guided and passes through the variable focus lens element 10 along the optical axis A located in the Z direction.

[0049] like Figure 1 As shown, when the light beam passes through the lens unit 20, it is polarized along the X direction, which is orthogonal to the Y and Z directions, forming X-polarized light 102. The polarization direction of the X-polarized light 102 is orthogonal to the alignment direction of the long axis L of the liquid crystal molecules 211. Under this condition, the X-polarized light 102 is considered ordinary ray, and the lens unit 20 has a first optical power Po.

[0050] like Figure 2 As shown, when the light beam (i.e., Y-polarized light 101) passes through the lens unit 20, it is polarized along the Y direction, and the polarization direction of the Y-polarized light 101 is parallel to the alignment direction of the long axis L of the liquid crystal molecules 211. Under this condition, the Y-polarized light 101 is considered an extraordinary ray, and the lens unit 20 has a second optical power Pe, which is different from the first optical power Po.

[0051] The polarization controller 30 is coupled to the lens unit 20 and can be switched between a first state and a second state via an electrically driven method.

[0052] When the light beam is guided along the optical axis A into the variable focal length lens element 10 and passes through the polarization controller 30 in the first state (see... Figure 1 When the beam polarization direction is changed by the polarization controller 30, for example: Figure 1 The Y-polarized light 101 shown is converted into X-polarized light 102 by the polarization controller 30. When the beam is guided along the optical axis A into the variable focal length lens element 10 and passes through the polarization controller 30 in the second state (see...), Figure 2 When this is done, it can prevent the polarization direction of the light beam from being changed by the polarization controller 30. For example: Figure 2 The Y-polarized light 101 shown is not converted by the polarization controller 30.

[0053] The polarization controller 30 is selected from twisted nematic (TN) liquid crystal elements, liquid crystal waveplates, and combinations thereof. In this embodiment, the polarization controller 30 is a twisted nematic liquid crystal element, which can switch between the first state (off state) and the second state (on state) in a very short time.

[0054] See Figure 3 This invention describes a first embodiment of the corrective lens assembly 300, suitable for everyday vision correction. The corrective lens assembly 300 includes at least one variable-focus lens element 10 and a polarizer 40. The polarizer 40 is used to transmit linearly polarized light to the at least one variable-focus lens element 10. The at least one variable-focus lens element 10 is arranged such that the polarization controller 30 is adjacent to and away from the lens unit 20, respectively.

[0055] In some embodiments, such as Figure 3 As shown, the corrective lens assembly 300 includes multiple variable focus lens elements 10a to 10n. When the polarization controllers 30 of all variable focus lens elements 10a to 10n are in the second state (start-up state), and a Y-polarized light 103 passes through the lens unit 20 of the variable focus lens elements 10a to 10n, each of the variable focus lens elements 10a to 10n has an optical power Pae to Pne. Under this condition, the optical power of the corrective lens assembly 300 is the sum of Pae to Pne (i.e., the sum of the optical powers of the variable focus lens elements 10a to 10n).

[0056] On the other hand, when one of the variable focus lens elements 10a is in the first state (off state), while the other variable focus lens elements 10b to 10n are in the second state (on state), and X-polarized light (not shown) passes through the lens unit 20 of the variable focus lens elements 10a to 10n, under these conditions, the optical power of the corrective lens assembly 300 is the sum of Pao to Pno (i.e., the sum of the optical power of the variable focus lens elements 10a to 10n). Therefore, by changing the state of the polarization controller 30 of the variable focus lens elements 10a to 10n, the optical power of the corrective lens assembly 300 has 2n possible variations. Therefore, the optical power of the corrective lens assembly 300 can be adjusted according to the vision correction required by a user's eye 100.

[0057] See Figures 4 to 7 This is a second embodiment of the corrective lens assembly 300 of the present invention. The second embodiment is similar to the first embodiment, except that the corrective lens assembly 300 of the second embodiment includes only two variable focus lens elements 10a and 10b, and has polarization controllers 30a and 30b, and lens units 20a and 20b, respectively.

[0058] When both polarization controllers 30a and 30b are in the first state (off state), the polarization conversion of the light beam in the corrective lens assembly 300 is as follows: Figure 4 As shown. Y-polarized light 104 is converted into X-polarized light 105 by the polarization controller 30a. Next, the X-polarized light 105 passes through the lens unit 20a, giving the lens unit 20a an optical power Pao. Then, the X-polarized light 105 is converted into Y-polarized light 106 by the polarization controller 30b. The Y-polarized light 106 passes through the lens unit 20b, giving the lens unit 20b an optical power Pbe. Therefore, in... Figure 4 Under the conditions shown, the optical power of the corrective lens assembly 300 is the sum of Pao and Pbe.

[0059] When the polarization controller 30a is in the second state (start state) and the polarization controller 30b is in the first state (off state), the polarization conversion of the light beam in the corrective lens assembly 300 is as follows: Figure 5 As shown. Y-polarized light 104 passes through the polarization controller 30a without being converted. Next, the Y-polarized light 104 passes through the lens unit 20a, giving the lens unit 20a an optical power Pae. Subsequently, the Y-polarized light 104 is converted into X-polarized light 107 by the polarization controller 30b. Then, the X-polarized light 107 passes through the lens unit 20b, giving the lens unit 20b an optical power Pbo. Therefore, in... Figure 5 Under the conditions shown, the optical power of the corrective lens assembly 300 is the sum of Pae and Pbo.

[0060] When the polarization controller 30a is in the first state (off state) and the polarization controller 30b is in the second state (on state), the polarization conversion of the light beam in the corrective lens assembly 300 is as follows: Figure 6 As shown. Y-polarized light 104 is converted into X-polarized light 105 by the polarization controller 30a. Next, the X-polarized light 105 passes through the lens unit 20a, giving the lens unit 20a an optical power Pao. Subsequently, the X-polarized light 105 passes through the polarization controller 30b without being converted. Then, the X-polarized light 105 passes through the lens unit 20b, giving the lens unit 20b an optical power Pbo. Therefore, in... Figure 6 Under the conditions shown, the optical power of the corrective lens assembly 300 is the sum of Pao and Pbo.

[0061] When both polarization controllers 30a and 30b are in the second state (start state), the polarization conversion of the light beam in the corrective lens assembly 300 is as follows: Figure 7 As shown. Y-polarized light 104 passes through the polarization controller 30a without being converted. Next, the Y-polarized light 104 passes through the lens unit 20a, giving the lens unit 20a an optical power Pae. Subsequently, the Y-polarized light 104 passes through the polarization controller 30b without being converted. Afterward, the Y-polarized light 104 passes through the lens unit 20b, giving the lens unit 20b an optical power Pbe. Therefore, in... Figure 7 Under the conditions shown, the optical power of the corrective lens assembly 300 is the sum of Pae and Pbe.

[0062] Therefore, when the corrective lens assembly 300 includes two variable focus lens elements 10a and 10b, the optical power of the corrective lens assembly 300 can have four possible variations.

[0063] See Figure 8 and Figure 9 This is a first embodiment of the optical display system 400 of the present invention. The optical display system 400 includes a variable focus lens element 10 and a display 50. The display 50 is used to provide a light beam to pass through the variable focus lens element 10. The variable focus lens element 10 is arranged such that the polarization controller 30 is adjacent to and the lens unit 20 is distant from the display 50, respectively. In some embodiments, the display 50 provides unpolarized light, and the optical display system 400 further includes a polarizer 40 (see...). Figure 8 , Figure 9 In some embodiments, if the display 50 provides linearly polarized light (e.g., Y-polarized light 201), the optical display system 400 does not configure the polarizer 40.

[0064] exist Figure 8 and Figure 9 In some embodiments, the optical display system 400 further includes a fixed-focus lens 60 disposed downstream of the display 50, allowing light from the display 50 to be transmitted to a viewer (represented by an eye 100) via the fixed-focus lens 60 and the at least one variable-focus lens element 10, thereby forming a virtual image V. The fixed-focus lens 60 can be selected from any optical lens having a desired focal length. In some embodiments, the fixed-focus lens 60 is disposed between the at least one variable-focus lens element 10 and the viewer.

[0065] When the polarization controller 30 of the variable focal length lens element 10 is in the first state, the polarization conversion of the light beam in the optical display system 400 is as follows: Figure 8 As shown, Y-polarized light 201 from the display 50 passes through the fixed-focus lens 60 and is converted into X-polarized light 202 by the polarization controller 30. The X-polarized light 202 passes through the lens unit 20, giving the lens unit 20 an optical power Po, and then travels to the viewer's eye 100. Under these conditions, the virtual image V is formed at a first distance d1 behind the display 50.

[0066] When the polarization controller 30 is in the second state, the polarization conversion of the light beam in the optical display system 400 is as follows: Figure 9 As shown, Y-polarized light 201 from the display 50 passes through the fixed-focus lens 60 and the polarization controller 30 without being converted. The Y-polarized light 201 then passes through the lens unit 20, giving the lens unit 20 an optical power Pe, and subsequently travels to the viewer's eye 100. Under these conditions, the virtual image V is formed at a second distance d2 behind the display 50, and the second distance d2 is smaller than the first distance d1.

[0067] Therefore, the formation position of the virtual image V can be moved by changing the state of the polarization controller 30 of the variable focus lens element 10.

[0068] In some embodiments, such as Figure 8 and Figure 9 The optical display system 400 shown can be used as part of a near-eye display suitable for a virtual reality (VR) system (not shown). The optical display system 400 can move the virtual image V by switching the state of the polarization controller 30 of the variable focus lens element 10. Furthermore, the optical display system 400 can be used to mitigate the visual convergence-accommodation conflict (VAC) caused by the near-eye display, and / or for vision correction in the near-eye display.

[0069] See Figures 10 to 13 This is a second embodiment of the optical display system 400 of the present invention. The optical display system 400 of the second embodiment is similar to the optical display system 400 of the first embodiment (e.g., Figure 8 Similar to (shown), the difference is that the optical display system 400 of the second embodiment includes three variable focus lens elements 10 (represented by 10a, 10b, and 10c respectively), each of the variable focus lens elements 10a, 10b, and 10c including polarization controllers 30a, 30b, and 30c, and lens units 20a, 20b, and 20c.

[0070] At Figure 10In this configuration, polarization controller 30a is in the first state, while polarization controllers 30b and 30c are in the second state. When Y-polarized light 203 from the display 50 passes through the fixed-focus lens 60, the Y-polarized light 203 is converted into X-polarized light 204 by polarization controller 30a. Then, the X-polarized light 204 sequentially passes through lens unit 20a, polarization controller 30b, lens unit 20b, polarization controller 30c, and lens unit 30c, finally reaching the viewer's eye 100. Therefore, in such a configuration... Figure 10 Under the conditions shown, the variable focus lens elements 10a, 10b, and 10c have optical power, which is the sum of Pao, Pbo, and Pco. In the embodiment, the virtual image V is formed at a distance X1 behind the display 50 (e.g., the distance X1 is approximately 480 cm).

[0071] exist Figure 11 In this configuration, polarization controllers 30a and 30c are in the second state, while polarization controller 30b is in the first state. When the Y-polarized light 203 from the display 50 passes through the fixed-focus lens 60, the polarization controller 30a, and the lens unit 20a, the Y-polarized light 203 is converted into X-polarized light 205 by the polarization controller 30b. Then, the X-polarized light 205 sequentially passes through the lens unit 20b, the polarization controller 30c, and the lens unit 30c, finally reaching the viewer's eye 100. Therefore, in Figure 11 Under the conditions shown, the variable focus lens elements 10a, 10b, and 10c have optical power, which is the sum of Pae, Pbo, and Pco. In the embodiment, the virtual image V is formed at a distance X2 behind the display 50, and the distance X2 is less than the distance X1 (e.g., the distance X2 is approximately 73 cm).

[0072] exist Figure 12 In this configuration, polarization controllers 30a and 30b are in the second state, while polarization controller 30c is in the first state. When the Y-polarized light 203 from the display 50 passes through the fixed-focus lens 60, the polarization controller 30a, the lens unit 20a, the polarization controller 30b, and the lens unit 20b, the Y-polarized light 203 is converted into X-polarized light 206 by the polarization controller 30c. Then, the X-polarized light 206 sequentially passes through the lens unit 20c and finally reaches the viewer's eye 100. Therefore, in Figure 12Under the conditions shown, the variable focus lens elements 10a, 10b, and 10c have optical power, which is the sum of Pae, Pbe, and Pco. In the embodiment, the virtual image V is formed at a distance X3 behind the display 50, and the distance X3 is less than the distance X2 (e.g., the distance X3 is approximately 35 cm).

[0073] exist Figure 13 In this context, the polarization controllers 30a, 30b, and 30c are in the second state. When the Y-polarized light 203 from the display 50 passes through the fixed-focus lens 60, the polarization controller 30a, the lens unit 20a, the polarization controller 30b, the lens unit 20b, the polarization controller 30c, and the lens unit 20c, it travels to the viewer's eye 100. Therefore, in... Figure 13 Under the conditions shown, the variable focus lens elements 10a, 10b, and 10c have optical power, which is the sum of Pae, Pbe, and Pce. In the embodiment, the virtual image V is formed at a distance X4 behind the display 50, and the distance X4 is less than the distance X3 (e.g., the distance X3 is approximately 21 cm).

[0074] See Figure 14 and Figure 15 This is a third embodiment of the optical display system 500 of the present invention. The optical display system 500 of the third embodiment is different from the optical display system 400 of the first embodiment (e.g., Figure 8 Similar to (shown), the difference is that the optical display system 500 also includes a beam splitter 70 for combining a beam from a real object and a beam from the display 50 and output by the at least one zoom lens element 10, which can be used as part of a near-eye display suitable for augmented reality (AR) systems (not shown).

[0075] In some embodiments, the beam splitter 70 is a polarization-independent beam splitter that reflects approximately 50% of the incident light and transmits approximately 50% of the light.

[0076] In some embodiments, such as Figure 14 and Figure 15 As shown, the beam splitter 70 is used to partially transmit a light beam, the light beam originating from the real object located in front of the beam splitter 70 and from the display 50 located to the right or left of the beam splitter 70. At least one variable focus lens element 10 is disposed between the beam splitter 70 and the display 50.

[0077] The fixed-focus lens 60 is used to guide a light beam from the display 50, passing through the variable-focus lens element 10, to the beam splitter 70. In some embodiments, such as Figure 14 and Figure 15 As shown, the fixed-focus lens 60 is disposed between the at least one variable-focus lens element 10 and the beam splitter 70. In other embodiments, the fixed-focus lens 60 is disposed between the at least one variable-focus lens element 10 and the display 50. When the display 50 provides unpolarized light, a polarizer 40 (see [reference needed]) is also required, located between the display 50 and the at least one variable-focus lens element 10. Figure 14 , Figure 15 When the display 50 provides linearly polarized light (e.g., Y-polarized light 301), the polarizer 40 is not required.

[0078] Figure 14 The optical path L1 for forming a virtual image V1 and the optical path L2 for forming a real-world image are described. A real object R1 is positioned away from the optical display system 500. When Y-polarized light 301 from the display 50 travels along the optical path L1 and passes through the polarization controller 30 in the first state, the Y-polarized light 301 is converted into X-polarized light 302. Then, the X-polarized light 302 travels along the optical path L1 through the lens unit 20, giving the lens unit 20 an optical power Po. The X-polarized light 302 continues to travel along the optical path L1 and, after passing through the fixed-focus lens 60, is split into two beams by the beam splitter 70, which travel along two branch paths L11 and L12 respectively. In other words, approximately 50% of the X-polarized light passes through the beam splitter 70 and travels along the branch path L11, while approximately 50% of the X-polarized light is reflected by the beam splitter 70 and travels along the branch path L12, reaching the viewer's eye 100. The X-polarized light traveling along the branch path L12 forms a virtual image V1 adjacent to the real object R1.

[0079] Furthermore, the light beam from the real object R1 travels along the light path L2 and passes through the beam splitter 70. Approximately 50% of the light beam traveling along the light path L2 passes through the beam splitter 70 and reaches the viewer's eye 100 along the branch path L21, while approximately 50% is reflected by the beam splitter 70 and travels along the branch path L22. The light beam traveling along the branch path L21 forms the real-world image.

[0080] Figure 15 Describe the optical path L3 used to form the virtual image V2, and the optical path L4 used to form the real-world image. Compared to... Figure 14The real objects R1 and R2 shown are positioned adjacent to the optical display system 500. When the Y-polarized light 301 from the display 50 travels along the optical path L3 and passes through the polarization controller 30 in the second state, it is prevented from being converted. Then, the Y-polarized light 301 passes through the lens unit 20, giving the lens unit 20 an optical power Pe. The Y-polarized light 301 continues to travel along the optical path L3 and, after passing through the fixed-focus lens 60, is split into two beams by the beam splitter 70, which travel along two branch paths L31 and L32 respectively. That is, about 50% of the Y-polarized light passes through the beam splitter 70 and travels along the branch path L31, while about 50% of the Y-polarized light is reflected by the beam splitter 70 and travels along the branch path L32, reaching the viewer's eye 100. Y-polarized light traveling along the branch path L32 will form a virtual image V2 adjacent to the real object R2.

[0081] Furthermore, the light beam from the real object R2 travels along the light path L4 and passes through the beam splitter 70. Approximately 50% of the light beam traveling along the light path L4 passes through the beam splitter 70 and reaches the viewer's eye 100 along the branch path L41, while approximately 50% is reflected by the beam splitter 70 and travels along the branch path L42. The light beam traveling along the branch path L41 forms the real-world image.

[0082] As described above, the formation position of the virtual image can be moved by changing the state of the polarization controller 30. In other embodiments (not shown), the optical display system 500 includes a plurality of variable focus lens elements 10; therefore, by switching the state of the polarization controller 30, the virtual image can be moved to a desired position. Furthermore, the optical display system 500 can be used to mitigate the visual convergence-accommodation conflict caused by the near-eye display.

[0083] See Figure 16 and Figure 17 This is a fourth embodiment of the optical display system 600 of the present invention. The optical display system 600 of the fourth embodiment and the optical display system 500 of the third embodiment (e.g.) Figure 14 Similar to (as shown), the difference lies in the relative positions of the at least one variable focus lens element 10 and the display 50, and the beam splitter 70 is located between the at least one variable focus lens element 10 and the display 50. Furthermore, the optical display system 600 is not equipped with... Figure 14 , Figure 15The illustrated fixed-focus lens 60 also includes a fixed-focus mirror 80 disposed outside the at least one variable-focus lens element 10, which allows the light beam from the display 50 to be reflected back to the beam splitter 70 after passing through the beam splitter 70 and the at least one variable-focus lens element 10. The fixed-focus mirror 80 can be selected from any reflective curved mirror with a desired focal length.

[0084] In some embodiments, if the display 50 provides unpolarized light, a polarizer 40 located between the display 50 and the at least one variable focus lens element 10 needs to be configured (see...). Figure 16 , Figure 17 For example, the polarizer 40 can be disposed between the display 50 and the beam splitter 70, or between the beam splitter 70 and the at least one variable focus lens element 10. In some embodiments, if the display 50 is used to provide linearly polarized light (e.g., Y-polarized light 401), the optical display system 600 will not be configured with the polarizer 40.

[0085] exist Figure 16 In the first state, the polarization controller 30 is in the first state, and the optical path L5 used to form the virtual image V3 is as follows: Figure 16As shown. The display 50 provides Y-polarized light 401, which travels along the optical path L5. The Y-polarized light 401 is guided by the beam splitter 70 and split into two beams, which travel along two branch paths L51 and L52, respectively. That is, about 50% of the Y-polarized light passes through the beam splitter 70 and travels along the branch path L51, while about 50% of the Y-polarized light is reflected by the beam splitter 70 and travels along the branch path L52, reaching the viewer's eye 100. The Y-polarized light traveling along the branch path L51 is converted into X-polarized light 402 by the polarization controller 30. The X-polarized light 402 then travels along the branch path L51, passes through the lens unit 20, and is reflected by the fixed-focus lens 80. Next, the reflected X-polarized light 403 travels along the branch path L51 again, passes through the lens unit 20, and is converted into Y-polarized light 404 by the polarization controller 30. The Y-polarized light 404 then travels along the branch path L51 and is split into two beams by the beam splitter 70, which travel along two secondary branch paths L511 and L512, respectively. That is, approximately 50% of the Y-polarized light passes through the beam splitter 70 and travels along the secondary branch path L511, while approximately 50% is reflected by the beam splitter 70 and travels along the secondary branch path L512 before reaching the viewer's eye 100. The light beam traveling along the secondary branch path L512 forms a virtual image V3 adjacent to the real object R3. Under these conditions, the light beam forming the virtual image V3 passes through the lens unit 20 twice, meaning the lens unit 20 can modulate the light beam twice. Therefore, the optical display system 600 has twice the optical power compared to the optical display system 500. In other words, when the polarization controllers 30 of both optical display systems 500 and 600 are in the second state, the virtual image formed by the optical display system 600 will be closer to the viewer.

[0086] Figure 17 A light path L6 is described for forming a real-world image. A light beam from a real object R3 travels along the light path L6 and passes through the beam splitter 70. Approximately 50% of the light beam traveling along the light path L6 is transmitted by the beam splitter 70 and reaches the viewer's eye 100 along a branch path L61. Approximately 50% is reflected by the beam splitter 70 and travels along a branch path L62. The light beam traveling along the branch path L61 forms the real-world image.

[0087] Furthermore, the formation position of the virtual image can be changed by altering the state of the polarization controller 30. In other embodiments (not shown), the optical display system 600 includes multiple variable-focus lens elements 10, thus allowing the virtual image to be formed at more possible positions by adjusting the state of the polarization controller 30 of the variable-focus lens elements 10. The optical display system 600 can also be used to mitigate the visual convergence-accommodation conflict caused by a near-eye display (not shown).

[0088] See Figure 18 This is a fifth embodiment of the optical display system 700 of the present invention, comprising at least one zoom lens element 10 and an augmented reality element 90. The augmented reality element 90 is used to direct a combined image from the at least one zoom lens element 10 to the viewer (represented by the viewer's eye 100). The augmented reality element 90 can be selected from any commercially available augmented reality element, or from the optical display systems 500 and 600 described above.

[0089] In some embodiments, the optical display system 700 further includes a polarizer 40 disposed between the augmented reality element 90 and the at least one variable focus lens element 10, for converting the light beam from the combined image into linearly polarized light and passing it through the at least one variable focus lens element 10.

[0090] In some embodiments, such as Figure 18 As shown, the optical display system 700 includes multiple variable focus lens elements 10a to 10n, which have similar functions to the variable focus lens elements 10a to 10n in the corrective lens assembly 300. That is, the total optical power of the variable focus lens elements 10a to 10n can be adjusted according to the visual correction needs of the viewer's eye 100. Therefore, when using the optical display system 700 to view a combined image, the viewer can directly view the combined image (i.e., the merged image of the virtual image V and the real-world image R) without wearing glasses or any vision correction device.

[0091] In summary, the variable focus lens element 10 of the present invention converts the polarization direction of the light beam by switching the state of its polarization controller 30, thereby giving the lens unit 20 different optical powers. The corrective lens assembly 300 can have a variety of possible optical power changes by switching the state of one or more of the variable focus lens elements 10 configured therein, which is suitable for daily vision correction. Similarly, the optical display systems 400, 500, 600, and 700 can move the formation position of the virtual image V according to the viewer's distance requirements by switching the state of one or more of the variable focus lens elements 10 configured therein, thereby mitigating the visual convergence-accommodation conflict caused by the near-eye display. Therefore, the purpose of the present invention can indeed be achieved.

[0092] The above description is only a preferred embodiment of the present invention, but it is not intended to limit the scope of the present invention. Any person skilled in the art can make further improvements and changes on this basis without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope defined in the claims of this application.

Claims

1. An optical display system, characterized by, A system comprising a display, at least one variable focus lens element, a beam splitter, and a fixed focus mirror, the display is configured to provide a light beam passing through the at least one variable focus lens element, the at least one variable focus lens element comprises a lens unit and a polarization controller, the lens unit comprises a polarization dependent lens and has different optical power for light beams of different polarization directions, the polarization controller is coupled to the lens unit and is capable of being switched from a first state to a second state via electrical driving, the lens unit and the polarization controller are respectively arranged in a manner of being adjacent to and being away from the display, the beam splitter is configured to combine a light beam from a real object and a light beam from the display and outputted by the at least one variable focus lens element, the beam splitter is configured to partially transmit the light beam from the real object located in front of the beam splitter, and the display is arranged on the left side or the right side of the beam splitter, the beam splitter is located between the at least one variable focus lens element and the display, and the fixed focus mirror is arranged outside the at least one variable focus lens element, so that the light beam from the display and passing through the beam splitter can be reflected by the fixed focus mirror back to the beam splitter, wherein, when the light beam is introduced into the at least one variable focus lens element along an optical axis located in the Z direction and passes through the polarization controller in the first state, the polarization direction of the light beam is converted by the polarization controller, and when the light beam is introduced into the at least one variable focus lens element along the optical axis and passes through the polarization controller in the second state, the polarization direction of the light beam is prevented from being converted by the polarization controller.

2. The optical display system of claim 1, wherein, Further comprising a polarizer arranged between the display and the at least one variable focus lens element.

3. The optical display system of claim 1, wherein, Further comprising a fixed focus lens arranged downstream of the display, the fixed focus lens is configured to enable the light beam from the display to be transmitted to a viewer via the fixed focus lens and the at least one variable focus lens element.

4. The optical display system of claim 1, wherein, The beam splitter is a polarization independent beam splitter.

5. The optical display system of claim 1, wherein, Further comprising an augmented reality element, the augmented reality element is configured to enable a combined image from the augmented reality element to be directed to a viewer via the at least one variable focus lens element.

6. The optical display system of claim 5, wherein, Further comprising a polarizer arranged between the augmented reality element and the at least one variable focus lens element, the polarizer is configured to convert the light beam from the combined image into linearly polarized light to pass through the at least one variable focus lens element.

7. The optical display system of claim 1, wherein, The lens unit further comprises a polarization independent lens.

8. The optical display system of claim 7, wherein, The polarization dependent lens and the polarization independent lens each have two surfaces, and the two surfaces are selected from one of a plane, a spherical surface, an aspherical surface, a free-form surface, a concave surface, and a convex surface.

9. The optical display system of claim 1, wherein, The polarization controller is selected from a twisted nematic liquid crystal element, a liquid crystal wave plate, and a combination thereof.

10. The optical display system of claim 1, wherein, The polarization-dependent lens has a plurality of liquid crystal molecules whose long axes are aligned along a Y direction orthogonal to the Z direction, and has a first optical power when a light beam polarized along an X direction orthogonal to the Y direction and the Z direction passes through the lens unit, and has a second optical power different from the first optical power when a light beam polarized along the Y direction passes through the lens unit.

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