Liquid crystal varifocus lens and electronic device

Abstract

A liquid crystal varifocus lens (100) and an electronic device, belonging to the technical field of liquid crystals. The liquid crystal varifocus lens (100) comprises two nematic liquid crystal lenses (10, 20), wherein the two nematic liquid crystal lenses (10, 20) are stacked, with the liquid crystal alignment directions of the two nematic liquid crystal lenses (10, 20) being perpendicular to each other; the nematic liquid crystal lenses (10, 20) comprise liquid crystal layers (11, 21) and lens layers (12, 22); and the refractive index of the liquid crystal layers (11, 21) and the refractive index of the lens layers (12, 22) of the two nematic liquid crystal lenses (10, 20) satisfy a preset relationship, such that the liquid crystal varifocus lens (100) is configured to have an optical power of 0 diopters in a power-off state. The liquid crystal varifocus lens (100) does not correct the vision of a user in the power-off state, preventing the liquid crystal varifocus lens (100) from remaining in a state with non-zero optical power, thereby avoiding potential safety hazards resulting from failure to switch states due to power depletion or a circuit fault.

Description

LCD zoom lenses and electronic devices Technical Field

[0001] This application relates to the field of liquid crystal technology, and in particular to a liquid crystal zoom lens and an electronic device. Background Technology

[0002] When people face vision problems such as nearsightedness, farsightedness, or presbyopia, they usually correct their vision by wearing glasses. Different users can choose the appropriate lenses based on their specific visual impairments.

[0003] Some users don't need to wear glasses all the time. For example, people with farsightedness usually need to wear glasses when reading or looking at distant objects, but not when looking at distant objects. This requires users to repeatedly put on and take off their glasses.

[0004] A liquid crystal zoom lens is a special type of lens used in eyeglasses, allowing the glasses to adjust their power according to the user's needs, eliminating the need for frequent wearing and removal of glasses. Typically, to achieve refractive index matching, the refractive index of the substrate material is set to match the refractive index of the liquid crystal molecules, for example, n... s =n o Or n s =n e With this setting, the effect is that the lens is in a focused state when no voltage is applied, and in a defocused state when voltage is applied.

[0005] However, considering the actual usage rate during actual use—that is, users will mostly be accustomed to being in a state without applying additional focal length—applying voltage (consuming more power) as described above would reduce the overall usage time. Furthermore, considering special scenarios such as when the battery is depleted or a circuit malfunction occurs, for safety reasons, the product should restore the user's original vision, an effect that the above configuration cannot achieve. This results in certain safety hazards associated with the current glasses in the event of a battery depletion or circuit failure. Summary of the Invention

[0006] This application provides a liquid crystal zoom lens and an electronic device, which helps to reduce safety hazards during use.

[0007] The technical solution is as follows:

[0008] In a first aspect, embodiments of this application provide a liquid crystal zoom lens, the liquid crystal zoom lens comprising two nematic liquid crystal lenses, the two nematic liquid crystal lenses being stacked, and the liquid crystal alignment directions of the two nematic liquid crystal lenses being perpendicular to each other;

[0009] The nematic liquid crystal lens includes a liquid crystal layer and a lens layer. The refractive indices of the liquid crystal layer and the refractive index of the lens layer of the two nematic liquid crystal lenses satisfy a preset relationship, so that the liquid crystal zoom lens is configured such that the focal length is 0 when the power is off.

[0010] In some examples, the liquid crystal zoom lens is also configured such that, in the energized state, the liquid crystal molecules in both nematic liquid crystal lenses are deflected so that the focal length of the liquid crystal zoom lens is not 0.

[0011] In some examples, the two nematic liquid crystal lenses include a first nematic liquid crystal lens and a second nematic liquid crystal lens; the first nematic liquid crystal lens includes a first liquid crystal layer, a first lens layer and two first substrates, the two first substrates are arranged in parallel and facing each other, the first liquid crystal layer is located between the two first substrates, and the first lens layer is located between the two first substrates and is located on the surface of the first substrate that is farther away from the second nematic liquid crystal lens.

[0012] The second nematic liquid crystal lens includes a second liquid crystal layer, a second lens layer, and two second substrates. The two second substrates are arranged in parallel and facing each other. The second liquid crystal layer is located between the two second substrates, and the second lens layer is located between the two second substrates and is located on the surface of the second substrate that is closer to the surface of the first nematic liquid crystal lens.

[0013] In some examples, the first nematic liquid crystal lens and the second nematic liquid crystal lens satisfy the following relationship: |(2n s1 -n e1 -n o1 )h1+(2n s2 -n e2 -n o2 h2|≤Δ1,

[0014] Where, n s1 n is the refractive index of the first lens layer; s2 n is the refractive index of the second lens layer; e1 n is the non-optical refractive index of the first liquid crystal layer; o1 n is the ordinary light refractive index of the first liquid crystal layer; e2 n is the optical refractive index of the second liquid crystal layer; o2 h1 is the ordinary light refractive index of the second liquid crystal layer; h2 is the thickness of the first lens layer; h3 is the thickness of the second lens layer; Δ1 is the first tolerance value.

[0015] In some examples, the optical refractive index n of the first liquid crystal layer e1 The refractive index n of the second liquid crystal layere2 The absolute value of the difference does not exceed the second tolerance value Δ2; and / or, the ordinary light refractive index n of the first liquid crystal layer o1 The ordinary light refractive index n of the second liquid crystal layer o2 The absolute value of the difference does not exceed the third tolerance value Δ3.

[0016] In some examples, the first liquid crystal layer and the second liquid crystal layer are formed using the same liquid crystal material.

[0017] In some examples, the thickness h1 of the first lens layer and the thickness h2 of the second lens layer are the same.

[0018] In some examples, the refractive index n of the first lens layer s1 and the refractive index n of the second lens layer s2 same.

[0019] In some examples, the absolute value of the difference between the focal power value of the first lens layer and the focal power value of the second lens layer does not exceed 200.

[0020] Secondly, embodiments of this application also provide an electronic device, the electronic device including a power supply and a liquid crystal zoom lens as described in the first aspect, the power supply being used to power the liquid crystal zoom lens.

[0021] In some examples, the electronic device further includes a third lens and a fourth lens, the third lens being located on one side of the liquid crystal zoom lens and the fourth lens being located on the other side of the liquid crystal zoom lens.

[0022] The beneficial effects of the technical solutions provided in this application include at least the following:

[0023] By stacking two nematic liquid crystal lenses with their liquid crystal alignment directions perpendicular to each other, and ensuring the refractive indices of the liquid crystal layers and lens layers satisfy a preset relationship, the power value of the liquid crystal zoom lens is 0 when the power is off, thus preventing the lens from correcting the user's vision. For users who wear farsighted glasses, they are accustomed to a state without additional power, i.e., without vision correction. When this liquid crystal zoom lens is applied to farsighted glasses, it does not correct the user's vision when the power is off, avoiding the safety hazards caused by the lens always being in a power-on state and unable to switch states. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 is a schematic diagram of the structure of a liquid crystal zoom lens provided in an embodiment of this application;

[0026] Figure 2 is a schematic diagram of the structure of a first nematic liquid crystal lens provided in an embodiment of this application;

[0027] Figure 3 is a schematic diagram of the refractive index of a liquid crystal zoom lens provided in an embodiment of this application;

[0028] Figure 4 is a schematic diagram of the refractive index of a liquid crystal zoom lens provided in an embodiment of this application;

[0029] Figure 5 is a schematic diagram of the structure of an electronic device provided in an embodiment of this application;

[0030] Figure 6 is a schematic diagram of the structure of an electronic device provided in an embodiment of this application.

[0031] Reference numerals in the figures: First nematic liquid crystal lens: 10; Second nematic liquid crystal lens: 20; First liquid crystal layer: 11; First lens layer: 12; First substrate: 13; Transparent electrode layer: 14; Alignment layer: 15; Frame: 16; Second liquid crystal layer: 21; Second lens layer: 22; Second substrate: 23; Optical adhesive: 30; Liquid crystal zoom lens: 100; Power supply: 200; Third lens: 300; Fourth lens: 400. Detailed Implementation

[0032] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0033] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0034] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0035] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0036] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0037] References to "one embodiment" or "some embodiments" in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized. "A plurality" means two or more.

[0038] This application provides a liquid crystal zoom lens, which includes two nematic liquid crystal lenses stacked together, with the liquid crystal alignment directions of the two nematic liquid crystal lenses perpendicular to each other. Each nematic liquid crystal lens includes a liquid crystal layer and a lens layer. The refractive indices of the liquid crystal layer and the lens layer satisfy a preset relationship, enabling the liquid crystal zoom lens to be configured such that its focal length is 0 in the power-off state.

[0039] By stacking two nematic liquid crystal lenses with their liquid crystal alignment directions perpendicular to each other, and ensuring the refractive indices of the liquid crystal layers and lens layers satisfy a preset relationship, the power value of the liquid crystal zoom lens is 0 when the power is off, thus preventing the lens from correcting the user's vision. For users who wear farsighted glasses, they are accustomed to a state without additional power, i.e., without vision correction. When this liquid crystal zoom lens is applied to farsighted glasses, it does not correct the user's vision when the power is off, avoiding the safety hazards caused by the lens always being in a power-on state and unable to switch states.

[0040] As an example, Figure 1 is a schematic diagram of a liquid crystal zoom lens provided in an embodiment of this application. As shown in Figure 1, the liquid crystal zoom lens includes a first nematic liquid crystal lens 10 and a second nematic liquid crystal lens 20, which are stacked together.

[0041] The liquid crystal in the first nematic liquid crystal lens 10 and the liquid crystal in the second nematic liquid crystal lens 20 are both nematic liquid crystals. The liquid crystal alignment direction of the first nematic liquid crystal lens 10 is perpendicular to the liquid crystal alignment direction of the second nematic liquid crystal lens 20.

[0042] The liquid crystal zoom lens has a power-off state and a power-on state. The refractive indices of the liquid crystal layers and the lens layers of the two nematic liquid crystal lenses satisfy a preset relationship, so that the liquid crystal zoom lens is configured to have a power value of 0 in the power-off state. In the power-on state, the liquid crystal molecules in the first nematic liquid crystal lens 10 and the liquid crystal molecules in the second nematic liquid crystal lens 20 are both deflected, so that the power value of the liquid crystal zoom lens is not 0. That is, in the power-on state, the power value of the liquid crystal zoom lens can be greater than 0 or less than 0.

[0043] In this embodiment, the energized state refers to the state in which the liquid crystal molecules in the first nematic liquid crystal lens 10 and the second nematic liquid crystal lens 20 are subjected to an electric field; the de-energized state refers to the state in which the liquid crystal molecules in the first nematic liquid crystal lens 10 and the second nematic liquid crystal lens 20 are not subjected to an electric field. For example, in the event of power depletion or circuit failure, no electric field is generated in the first nematic liquid crystal lens 10 and the second nematic liquid crystal lens 20 to act on the liquid crystal molecules, therefore, in this case, the liquid crystal zoom lens is in the de-energized state.

[0044] By stacking a first nematic liquid crystal lens 10 and a second nematic liquid crystal lens 20, with the liquid crystal alignment direction of the first nematic liquid crystal lens 10 perpendicular to that of the second nematic liquid crystal lens 20, the effects of birefringence can be eliminated, avoiding ghosting. When the liquid crystal zoom lens is energized, the liquid crystal molecules in both the first nematic liquid crystal lens 10 and the second nematic liquid crystal lens 20 are deflected, resulting in a non-zero power value, allowing the liquid crystal zoom lens to correct the user's vision. When the liquid crystal zoom lens is de-energized, its power value is zero, meaning it does not correct the user's vision. For users wearing farsighted glasses, most of the time they are accustomed to a state without additional power, i.e., without vision correction. When this liquid crystal zoom lens is applied to farsighted glasses, the lens does not correct the user's vision when the power is off, avoiding the safety hazards caused by the liquid crystal zoom lens always being in a power-on state and unable to switch states.

[0045] Taking the application of a liquid crystal zoom lens in eyeglasses for farsighted users as an example, in actual use, users only need the glasses to correct their vision in scenarios such as reading. Most of the time, users are accustomed to a state without additional focal length. When using eyeglasses with the liquid crystal zoom lens provided in this embodiment, during scenarios such as reading, the liquid crystal zoom lens can be energized. The liquid crystal molecules in the first nematic liquid crystal lens 10 and the second nematic liquid crystal lens 20 are deflected, and the focal length of the liquid crystal zoom lens is not 0, thus applying additional focal length to the human eye, allowing the user to see objects at close range clearly. When reading ends and the user transitions to walking, the liquid crystal zoom lens is de-energized, and its focal length is 0, applying no additional focal length to the human eye. The user's vision returns to its original level, allowing the user to see objects at a distance clearly. Because the power value of the liquid crystal zoom lens is 0 when the power is off, it will also become 0 when the glasses run out of power or experience a circuit malfunction. This restores the user's vision to its original level, preventing safety hazards caused by the user's vision not returning to its original state when transitioning from reading to walking, or in other similar situations. Hyperopia is a common visual impairment among the elderly. Using glasses with the liquid crystal zoom lens provided in this embodiment can significantly reduce the risk of falls and bumps caused by changes in usage scenarios and the inability to restore vision.

[0046] As shown in Figure 1, the first nematic liquid crystal lens 10 includes a first liquid crystal layer 11, a first lens layer 12, and two first substrates 13. The two first substrates 13 are arranged in parallel and facing each other. The first liquid crystal layer 11 is located between the two first substrates 13, and the first lens layer 12 is located between the two first substrates 13, and is located on the surface of the first substrate 13 that is farther away from the second nematic liquid crystal lens 20. The refractive index of the first nematic liquid crystal lens 10 includes at least the refractive index of the first liquid crystal layer 11 and the refractive index of the first lens layer 12.

[0047] The second nematic liquid crystal lens 20 includes a second liquid crystal layer 21, a second lens layer 22, and two second substrates 23. The two second substrates 23 are arranged in parallel and facing each other. The second liquid crystal layer 21 is located between the two second substrates 23, and the second lens layer 22 is located between the two second substrates 23, and is located on the surface of the second substrate 23 that is closer to the surface of the second substrate 23 of the first nematic liquid crystal lens 10. The refractive index of the second nematic liquid crystal lens 20 includes at least the refractive index of the second liquid crystal layer 21 and the refractive index of the second lens layer 22.

[0048] The first lens layer 12 and the second lens layer 22 are used to provide the phase distribution required to achieve the lens effect. The first lens layer 12 and the second lens layer 22 can be any one of a refractive lens, a diffractive lens, or a superlens. For example, the first lens layer 12 and the second lens layer 22 can be Fresnel lenses.

[0049] Figure 2 is a schematic diagram of a first nematic liquid crystal lens provided in an embodiment of this application. As shown in Figure 2, the first nematic liquid crystal lens 10 further includes two transparent electrode layers 14, two alignment layers 15, and a frame 16. The two transparent electrode layers 14 are located between two first substrates 13, with one transparent electrode layer 14 located on the surface of one first substrate 13 and the other transparent electrode layer 14 located on the surface of the first lens layer 12 near the first liquid crystal layer 11. The two alignment layers 15 are located between the two transparent electrode layers 14, with one alignment layer 15 located on the surface of one transparent electrode layer 14 and the other alignment layer 15 located on the surface of the other transparent electrode layer 14. The frame 16 is located between the two first substrates 13 and is arranged along the edge of the first substrate 13. The frame 16 and the two first substrates 13 form a housing, in which the first liquid crystal layer 11 is located. The first liquid crystal layer 11 can be injected into the housing by drop-in injection or vacuum crystal injection.

[0050] In other examples, the transparent electrode layer 14 located on the surface of the first lens layer 12 may also be arranged on the surface of the first lens layer 12 away from the first liquid crystal layer 11, and the alignment layer 15 located on the surface of the transparent electrode layer 14 may be arranged on the surface of the first lens layer 12 close to the first liquid crystal layer 11.

[0051] The first substrate 13 can be a transparent glass substrate or a substrate of a synthetic material, wherein the synthetic material can be, but is not limited to, polyethylene terephthalate (PET), polycarbonate (PC), or cellulose triacetate (TAC).

[0052] As an example, the thickness of the first substrate 13 can be from 1 μm to 2000 μm.

[0053] The first lens layer 12 can be directly fabricated on the surface of the first substrate 13, or it can be bonded to the first substrate 13 by adhesive bonding.

[0054] The structure of the second nematic liquid crystal lens 20 can be the same as that of the first nematic liquid crystal lens 10, and will not be described in detail here.

[0055] In some examples, the first nematic liquid crystal lens 10 and the second nematic liquid crystal lens 20 can be bonded together, for example, by means of transparent optical adhesive 30.

[0056] In some other possible implementations, the first substrate 13 of the first nematic liquid crystal lens 10 near the second nematic liquid crystal lens 20 and the second substrate 23 of the second nematic liquid crystal lens 20 near the first nematic liquid crystal lens 10 can also be an integral structure, that is, the first nematic liquid crystal lens 10 and the second nematic liquid crystal lens 20 can share a single substrate.

[0057] There can be multiple preset relationships that satisfy the refractive index of the liquid crystal layer and the refractive index of the lens layer of two nematic liquid crystal lenses. For example, the preset relationship can include any one of the six relationships shown in equations (A) to (F) below.

[0058] In some examples, the first nematic liquid crystal lens 10 and the second nematic liquid crystal lens 20 satisfy the following relationship: |(2n s1 -n e1 -n o1 )h1+(2n s2 -n e2 -n o2 h2|≤Δ1 (A)

[0059] Where, n s1 n is the refractive index of the first lens layer 12; s2 n is the refractive index of the second lens layer 22; e1 n is the optical refractive index of the first liquid crystal layer 11; o1 n is the ordinary light refractive index of the first liquid crystal layer 11; e2 n is the optical refractive index of the second liquid crystal layer 21; o2h1 is the ordinary light refractive index of the second liquid crystal layer 21; h2 is the thickness of the first lens layer 12; h2 is the thickness of the second lens layer 22; Δ1 is the first tolerance value.

[0060] For a first nematic liquid crystal lens 10 and a second nematic liquid crystal lens 20 with identical structures, by making the refractive index of the first lens layer 12 and the refractive index of the second lens layer 22 both half the sum of the biaxial refractive indices of the liquid crystal molecules, that is, half the sum of the extraordinary refractive index and the ordinary refractive index, the power of the liquid crystal zoom lens is 0 in the off-state, i.e., when no electric field is applied to the first nematic liquid crystal lens 10 and the second nematic liquid crystal lens 20 to deflect the liquid crystal molecules. However, after applying an electric field, the liquid crystal molecules deflect, and the power of the liquid crystal zoom lens is not 0.

[0061] In actual production, the first nematic liquid crystal lens 10 and the second nematic liquid crystal lens 20 may not be exactly the same. By setting a first tolerance value Δ1 and ensuring that the relevant parameters of the first nematic liquid crystal lens 10 and the second nematic liquid crystal lens 20 satisfy the above relationship, the effect produced by the liquid crystal zoom lens in the power-off state can meet the design requirements.

[0062] The value of the first tolerance Δ1 can be set according to the design requirements. For example, the first tolerance Δ1 can be 0, 0.01, 0.05, 0.1, 0.15, 0.2, etc.

[0063] Among them, the structures are completely identical, including the first liquid crystal layer 11 and the second liquid crystal layer 21 made of the same material, the first lens layer 12 and the second lens layer 22 made of the same material, and the first nematic liquid crystal lens 10 and the second nematic liquid crystal lens 20 having the same size.

[0064] In some examples, the optical refractive index n of the first liquid crystal layer 11 e1 The refractive index n of the second liquid crystal layer 21 e2 The absolute value of the difference does not exceed the second tolerance value Δ2; and / or, the ordinary light refractive index n of the first liquid crystal layer 11 o1 With the ordinary light refractive index n of the second liquid crystal layer 21 o2 The absolute value of the difference does not exceed the third tolerance value Δ3.

[0065] The second tolerance value Δ2 and the third tolerance value Δ3 can be set according to specific design requirements. For example, the second tolerance value Δ2 can be any value between 0 and 0.2. For example, the second tolerance value Δ2 can be 0, 0.05, 0.1, 0.15, or 0.2. The third tolerance value Δ3 can also be any value between 0 and 0.2. For example, the third tolerance value Δ3 can be 0, 0.05, 0.1, 0.15, or 0.2.

[0066] By adjusting the very light refractive index n of the first liquid crystal layer 11 e1 The refractive index n of the second liquid crystal layer 21 e2 The absolute value of the difference is controlled within the second tolerance value Δ2, thereby controlling the ordinary light refractive index n of the first liquid crystal layer 11. o1 With the ordinary light refractive index n of the second liquid crystal layer 21 o2 The absolute value of the difference is controlled within the third tolerance value Δ3, so that the difference in the refraction of light by the first liquid crystal layer 11 and the second liquid crystal layer 21 is smaller, and the focal length value presented by the liquid crystal zoom lens in the power-off state and the power-on state is more accurate.

[0067] As an example, the first liquid crystal layer 11 and the second liquid crystal layer 21 are formed using the same liquid crystal material.

[0068] The first liquid crystal layer 11 and the second liquid crystal layer 21 are formed using the same liquid crystal material, such that the refractive index n of the first liquid crystal layer 11 is... e1 The refractive index n of the second liquid crystal layer 21 e2 Similarly, the ordinary light refractive index n of the first liquid crystal layer 11 o1 With the ordinary light refractive index n of the second liquid crystal layer 21 o2 The same principle applies, which helps to further improve the accuracy of the focal length value presented by the liquid crystal zoom lens in both power-off and power-on states.

[0069] Using the same liquid crystal material to form the first liquid crystal layer 11 and the second liquid crystal layer 21, the aforementioned relationship (A) can be simplified to the following relationship: |(2n s1 -n e -n o )h1+(2n s2 -n e -n o h2|≤Δ1 (B)

[0070] Where, n e n is the extremely high refractive index of the liquid crystal material; o is the ordinary light refractive index of the liquid crystal material.

[0071] The simplified relation (B) has fewer parameters, making the fabrication of liquid crystal zoom lenses simpler.

[0072] In some examples, the absolute value of the difference between the power values ​​of the first lens layer 12 and the second lens layer 22 does not exceed 200. A small difference in the power values ​​of the two lenses is beneficial for improving image quality.

[0073] For example, the difference between the focal power value of the first lens layer 12 and the focal power value of the second lens layer 22 is 0, that is, the focal power values ​​of the first lens layer 12 and the second lens layer 22 are the same.

[0074] In some examples, the thickness h1 of the first lens layer 12 is the same as the thickness h2 of the second lens layer 22.

[0075] By setting the thicknesses of the first lens layer 12 and the second lens layer 22 to be the same, the aforementioned relationship (B) can be further simplified. The simplified relationship is as follows: |n s1 +n s2 -n e -n o |≤Δ1 / h (C)

[0076] Where h is the thickness of the first lens layer 12 or the second lens layer 22.

[0077] In the most ideal state, the first tolerance value Δ1 is 0. When the thicknesses of the first lens layer 12 and the second lens layer 22 are the same, the relationship (C) becomes independent of the thickness h, and only related to the refractive index n of the first lens layer 12. s1 The refractive index n of the second lens layer 22 s2 The exceptional refractive index n of liquid crystal materials e The ordinary optical refractive index n of liquid crystal materials o This is relevant. It can be seen that the simplified equation (C) has fewer parameters, making the fabrication of liquid crystal zoom lenses simpler.

[0078] When the first tolerance value Δ1 is 0, the relation (C) can be simplified to the following relation: n s1 +n s2 =n e +n o (D)

[0079] In other words, the sum of the refractive indices of the first lens layer 12 and the second lens layer 22 is equal to the optical refractive index n of the liquid crystal material. e The ordinary optical refractive index n of liquid crystal materials o The sums must be equal.

[0080] Figure 3 is a schematic diagram of the refractive index of a liquid crystal zoom lens according to an embodiment of this application. As shown in Figure 3, light is incident from the first nematic liquid crystal lens 10 and exits from the second nematic liquid crystal lens 20. The refractive index of the first lens layer 12 is n. s The refractive index of the second lens layer 22 is n e +n o -n s .

[0081] During the process of light passing through the liquid crystal zoom lens, the refractive index of the first lens layer 12 for both extraordinary and ordinary rays remains constant, regardless of whether the power is off or on. sThe refractive index of the second lens layer 22 for both extraordinary and ordinary light is always n. e +n o -n s The first liquid crystal layer 11 has the same effect on ordinary light but a different effect on extraordinary light, while the second liquid crystal layer 21 has a different effect on ordinary light but the same effect on extraordinary light.

[0082] Furthermore, in some examples, the refractive index n of the first lens layer 12 s1 The refractive index n of the second lens layer 22 s2 The same applies. This further simplifies the manufacturing of liquid crystal zoom lenses.

[0083] As an example, the first lens layer 12 and the second lens layer 22 can be made of the same material, so that the first lens layer 12 and the second lens layer 22 have the same refractive index.

[0084] The first lens layer 12 and the second lens layer 22 have the same refractive index, and the relationship (C) can be further simplified as follows: |2n s -n e -n o |≤Δ1 / h (E)

[0085] Where, n s The refractive index is the refractive index of the first lens layer 12 or the second lens layer 22.

[0086] In the most ideal state, the first tolerance value Δ1 is 0, and the relationship (E) can be further simplified as follows: 2n s =n e +n o (F)

[0087] In other words, when the materials of the first liquid crystal layer 11 and the second liquid crystal layer 21 are the same, and the thicknesses of the first lens layer 12 and the second lens layer 22 are the same, the refractive index of the first lens layer 12 and the refractive index of the second lens layer 22 are both the optical refractive index n of the liquid crystal material. e And the ordinary refractive index n o The arithmetic mean of the arithmetic mean can make the focal length of the liquid crystal zoom lens zero when the power is off, but not zero when the power is on.

[0088] Figure 4 is a schematic diagram of the refractive index of a liquid crystal zoom lens according to an embodiment of this application. As shown in Figure 4, light is incident from the first nematic liquid crystal lens 10 and exits from the second nematic liquid crystal lens 20. During the passage of light through the liquid crystal zoom lens, in both the power-off and power-on states, the refractive index of the first lens layer 12 and the second lens layer 22 for both ordinary and extraordinary light is always equal to the ordinary light refractive index n of the liquid crystal material.e And the ordinary refractive index n o The arithmetic mean. The first liquid crystal layer 11 has the same effect on ordinary light but a different effect on extraordinary light, while the second liquid crystal layer 21 has a different effect on ordinary light but the same effect on extraordinary light.

[0089] Figure 5 is a schematic diagram of an electronic device provided in an embodiment of this application. The electronic device can be eyeglasses or a wearable display (such as a head-mounted display). As shown in Figure 5, the electronic device includes a power supply 200 and a liquid crystal zoom lens 100, with the power supply 200 providing power to the liquid crystal zoom lens 100.

[0090] For example, the power supply 200 can be electrically connected to the transparent electrode layer 14 in the aforementioned first nematic liquid crystal lens 10 and second nematic liquid crystal lens 20 to provide voltage and control the operation of the first liquid crystal layer 11 and the second liquid crystal layer 21.

[0091] In this electronic device, by stacking a first nematic liquid crystal lens 10 and a second nematic liquid crystal lens 20, with the liquid crystal alignment direction of the first nematic liquid crystal lens 10 perpendicular to that of the second nematic liquid crystal lens 20, the effects of birefringence can be eliminated, avoiding ghosting. When the electronic device's liquid crystal zoom lens 100 is powered on, the liquid crystal molecules in both the first nematic liquid crystal lens 10 and the second nematic liquid crystal lens 20 are deflected, and the power value of the liquid crystal zoom lens 100 is not zero, allowing it to correct the user's vision. When the power is off, the power value of the liquid crystal zoom lens 100 is zero, allowing the user's vision to return to its original state without being affected by the liquid crystal zoom lens 100. This avoids the safety hazard caused by the liquid crystal zoom lens 100 remaining in a power-on state during power outages and being unable to switch states. The proportion of farsightedness-related vision impairment is relatively high among the elderly. Using glasses with liquid crystal zoom lenses provided in the embodiments of this application can greatly reduce the risk of falls and bumps caused by changes in usage scenarios and irreversible vision loss in the elderly.

[0092] Figure 6 is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. As shown in Figure 6, compared with the electronic device shown in Figure 5, the electronic device may also include a third lens 300 and a fourth lens 400. The third lens 300 is located on one side of the liquid crystal zoom lens 100, and the fourth lens 400 is located on the other side of the liquid crystal zoom lens 100.

[0093] The liquid crystal zoom lens 100 is arranged on the third lens 300 and the fourth lens 400 to form a combined lens. The focal length value generated by the liquid crystal zoom lens 100 is superimposed with the focal length values ​​of the third lens 300 and the fourth lens 400, so that the combined lens can produce higher or lower focal length values ​​to meet the needs of different users.

[0094] For example, the third lens 300 can be any one of a refractive lens, a liquid crystal lens, or a superlens, and the fourth lens 400 can also be any one of a refractive lens, a liquid crystal lens, or a superlens.

[0095] For example, the third lens 300 can be a plano-concave lens, and the fourth lens 400 can be a plano-convex lens.

[0096] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A liquid crystal zoom lens, characterized in that, It includes two nematic liquid crystal lenses, which are stacked and whose liquid crystal alignment directions are perpendicular to each other; The nematic liquid crystal lens includes a liquid crystal layer and a lens layer. The refractive indices of the liquid crystal layer and the refractive index of the lens layer of the two nematic liquid crystal lenses satisfy a preset relationship, so that the liquid crystal zoom lens is configured such that the focal length is 0 when the power is off.

2. The liquid crystal zoom lens according to claim 1, characterized in that, The liquid crystal zoom lens is further configured such that, in the energized state, the liquid crystal molecules in both nematic liquid crystal lenses are deflected so that the focal length of the liquid crystal zoom lens is not 0.

3. The liquid crystal zoom lens according to claim 1 or 2, characterized in that, The two nematic liquid crystal lenses include a first nematic liquid crystal lens (10) and a second nematic liquid crystal lens (20); The first nematic liquid crystal lens (10) includes a first liquid crystal layer (11), a first lens layer (12), and two first substrates (13). The two first substrates (13) are arranged in parallel and facing each other. The first liquid crystal layer (11) is located between the two first substrates (13), and the first lens layer (12) is located between the two first substrates (13) and is located on the surface of the first substrate (13) that is farther away from the second nematic liquid crystal lens (20). The second nematic liquid crystal lens (20) includes a second liquid crystal layer (21), a second lens layer (22), and two second substrates (23). The two second substrates (23) are arranged in parallel and facing each other. The second liquid crystal layer (21) is located between the two second substrates (23), and the second lens layer (22) is located between the two second substrates (23) and is located on the surface of the second substrate (23) that is closer to the first nematic liquid crystal lens (10).

4. The liquid crystal zoom lens according to claim 3, characterized in that, The first nematic liquid crystal lens (10) and the second nematic liquid crystal lens (20) satisfy the following relationship: |(2n s1 -n e1 -n o1 )h1+(2n s2 -n e2 -n o2 h2|≤Δ1, Where, n s1 n is the refractive index of the first lens layer (12); s2 n is the refractive index of the second lens layer (22); e1 n is the optical refractive index of the first liquid crystal layer (11); o1 n is the ordinary light refractive index of the first liquid crystal layer (11); e2 n is the optical refractive index of the second liquid crystal layer (21); o2 h1 is the ordinary light refractive index of the second liquid crystal layer (21); h2 is the thickness of the first lens layer (12); h2 is the thickness of the second lens layer (22); Δ1 is the first tolerance value.

5. The liquid crystal zoom lens according to claim 4, characterized in that, The optical refractive index n of the first liquid crystal layer (11) e1 The refractive index n of the second liquid crystal layer (21) e2 The absolute value of the difference does not exceed the second tolerance value Δ2; and / or, the ordinary light refractive index n of the first liquid crystal layer (11) o1 The ordinary light refractive index n of the second liquid crystal layer (21) o2 The absolute value of the difference does not exceed the third tolerance value Δ3.

6. The liquid crystal zoom lens according to claim 5, characterized in that, The first liquid crystal layer (11) and the second liquid crystal layer (21) are formed using the same liquid crystal material.

7. The liquid crystal zoom lens according to any one of claims 4 to 6, characterized in that, The thickness h1 of the first lens layer (12) is the same as the thickness h2 of the second lens layer (22).

8. The liquid crystal zoom lens according to any one of claims 4 to 6, characterized in that, The refractive index n of the first lens layer (12) s1 and the refractive index n of the second lens layer (22) s2 same.

9. The liquid crystal zoom lens according to any one of claims 4 to 6, characterized in that, The absolute value of the difference between the power value of the first lens layer (12) and the power value of the second lens layer (22) does not exceed 200.

10. An electronic device, characterized in that, It includes a power supply (200) and a liquid crystal zoom lens (100) as described in any one of claims 1 to 9, wherein the power supply (200) is used to supply power to the liquid crystal zoom lens (100).

11. The electronic device according to claim 10, characterized in that, The electronic device further includes a third lens (300) and a fourth lens (400), the third lens (300) being located on one side of the liquid crystal zoom lens (100) and the fourth lens (400) being located on the other side of the liquid crystal zoom lens (100).

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