KR20230073942A - Contact lenses having mutiple wave plate - Google Patents

Abstract

The present invention relates to a contact lens composed of a multi-layer wave plate capable of increasing the number of focal points by disposing two or more wave plates between a corneal protective layer and a lens surface layer of the contact lens, comprising: a lens surface layer; corneal protective layer; and a wave plate layer in which two or more wave plates made of a birefringent material are stacked and disposed between the lens surface layer and the cornea protective layer, wherein the phases of each adjacent wave plate in the wave plate layer are complementary to each other. It is characterized in that the phase code is reversed.

Description

Contact lens made of multilayer wave plate {CONTACT LENSES HAVING MUTIPLE WAVE PLATE}

The present invention relates to a contact lens composed of a multi-layer wave plate, and more particularly, to a contact lens composed of a multi-layer wave plate capable of increasing the number of focal points by disposing two or more wave plates between a corneal protective layer and a lens surface layer of the contact lens. It's about contact lenses.

Common disorders of visual impairment include myopia and hyperopia. These disorders are usually due to an imbalance between the length of the eye and the focus of the optical elements of the eye. Myopic eyes focus on the front of the retinal plane, and farsighted eyes focus on the back of the retinal plane. Myopia typically occurs because the axial length of the eye grows longer than the focal length of the optical components of the eye, that is, the eye grows too long. Hyperopia typically occurs because the axial length of the eye is too short compared to the focal length of the optical components of the eye, i.e., the eye does not grow long enough.

The ability to adjust the focal length, i.e. the ability to focus near and far objects without depending on focal length changes, can be enhanced by the use of intraocular multifocal lenses or contact lenses and the like. Multifocal lenses have different focal lengths for near and far vision.

Among the techniques for manufacturing a multifocal diffractive lens, a method including a diffractive waveplate element made of a birefringent material is known. This method has advantages in that the manufacturing process is relatively easy and the cost is low.

As a prior art related to a multifocal lens having a diffractive waveplate element, US registered patent US 9,753,193 (METHODS AND APPARATUS FOR HUMAN VISION CORRECTION USING DIFFRACTIVE WAVEPPLATE LENSES) is disclosed.

However, according to the US registered patent US 9,753,193, the overall structure is a single thin film layer, so in order to form a double or triple or more multifocal while minimizing phase distribution and optical aberration, a high-speed birefringent material arranged in a single thin film layer is used. and the low-speed shaft arrangement must be properly arranged, but this process is very complicated.

US Registered Patent US 9,753,193

An object of the present invention is to provide a contact lens made of multi-layered wave plates capable of increasing the number of focal points compared to a conventional contact lens by stacking and arranging a plurality of wave plates on the contact lens so as to have phases in a mutually complementary relationship.

A contact lens made of a multilayer wave plate according to the present invention for achieving the above object includes a lens surface layer; corneal protective layer; and a wave plate layer in which two or more wave plates made of a birefringent material are stacked and disposed between the lens surface layer and the cornea protective layer, wherein the phases of each adjacent wave plate in the wave plate layer are complementary to each other. It is characterized in that the phase code is reversed.

In addition, in one embodiment of the present invention, when the thickness of one or more wave plates in the wave plate layer is changed, the light intensity at the position where the focus is formed is changed accordingly.

Further, in one embodiment of the present invention, when the thickness of the wave plate layer is adjusted so that the light intensity at a position where one of the focal points is formed is zero, the number of focal points is changed.

In addition, in one embodiment of the present invention, the number of foci generated by the wave plate layer is characterized in that it is calculated by Equation 1 below.

<Equation 1>

Here, N is the maximum number of foci and m is the number of waveplates.

In addition, in one embodiment of the present invention, the position of the focal point generated by the wave plate layer is characterized in that it is calculated as in Equation 2 below according to the number of the wave plate.

< Equation 2 >

은 마지막 파장판을 통과한 후의 초점 거리이고,

은 각 파장판의 초점 거리임.here,

is the focal length after passing through the last wave plate,

is the focal length of each waveplate.

In addition, in one embodiment of the present invention, when the phase interval (X) between the point where the phase changes rapidly at the center of the lens in the phase distribution of the wave plate layer changes, the position where the focus is formed changes accordingly.

In addition, in an embodiment of the present invention, in the same phase period (X) between first and second wave plates adjacent to each other in the wave plate layer, when the phase in the first wave plate increases, the second wave plate The phase of is characterized by decreasing.

Further, in one embodiment of the present invention, the wave plate layer is characterized in that it is disposed in the central region of the corneal protective layer.

Further, in one embodiment of the present invention, the wave plate layer disposed in the central region is characterized in that it has a smaller area than the corneal protective layer.

In addition, in one embodiment of the present invention, one of the wave plate layers is disposed in the central region of the corneal protection layer, and another wave plate layer is disposed in the peripheral region excluding the central region in the outer direction of the central region. It is characterized in that it is arranged spaced apart from the area by a certain distance.

In addition, in one embodiment of the present invention, the wave plate layer disposed in the peripheral region is characterized in that it is formed in an annular shape with a constant thickness.

In addition, in one embodiment of the present invention, a plurality of wave plate layers disposed in the peripheral region are formed in an annular shape with a constant thickness, have different radii, and are spaced apart from adjacent wave plate layers by a predetermined distance.

In addition, in one embodiment of the present invention, the wave plate layer is characterized in that it is disposed in the peripheral region except for the central region of the corneal protective layer.

Further, in one embodiment of the present invention, the wave plate layer is characterized in that it is formed to surround the circumference of the corneal protective layer.

In addition, in one embodiment of the present invention, the wave plate layer is characterized in that formed inside the corneal protective layer.

In addition, in one embodiment of the present invention, the wave plate layer is characterized in that it is formed in an annular shape with a constant thickness.

Further, in one embodiment of the present invention, one of the wave plate layers is disposed in the first peripheral region excluding the central region of the corneal protection layer, and another wave plate layer is disposed in the outer direction of the first peripheral region. It is characterized in that it is disposed in a second peripheral area spaced apart from the first peripheral area by a predetermined distance.

In addition, in one embodiment of the present invention, a plurality of wave plate layers disposed in the second peripheral region are formed in an annular shape with a constant thickness, have different radii, and are spaced apart from adjacent wave plate layers by a predetermined distance. .

According to the present invention, the number of focal points can be increased in proportion to the number of wave plates, and a contact lens having multifocality can be easily manufactured using this.

In addition, the present invention can be generally applied to industrial fields requiring multifocal lenses, such as microscopes and cameras, as well as for vision correction.

In addition, in the present invention, the total number of wave plates, the curvature of the lens surface layer, and the refractive index distribution of each wave plate may be variously changed to achieve refractive compensation required for distance and near vision together with other lenses of the visual system.

In addition, when the thickness of the wave plate is changed, the degree of light intensity at the position where the focus is formed is changed, so that the number of focus points can be adjusted within the limit of the maximum number of focus points.

1 is a diagram showing the overall configuration of a contact lens made of a multilayer wave plate according to an embodiment of the present invention.
2 and 3 are views showing the structure of a contact lens made of a multilayer wave plate according to an embodiment of the present invention.
4 is a view showing a cross section of a conventional diffractive lens.
5 is a diagram illustrating a phase distribution of a wave plate according to an embodiment of the present invention.
6 is a view showing a state in which one wave plate is disposed on a contact lens.
FIG. 7 is a view showing positions of focal points and light intensity distribution according to a change in the thickness of the wave plate in FIG. 6 .
FIG. 8 is a view showing a state in which two wave plates that do not complement each other are stacked and disposed on a contact lens.
FIG. 9 is a view showing positions of focal points and light intensity distribution when each thickness of the wave plate in FIG. 8 is λ/4.
10 is a view showing a state in which multiple focal points are formed when two wave plates whose phases are complementary to each other are stacked and disposed in a contact lens according to an embodiment of the present invention.
11 is a view showing a change in light intensity at each focal position according to a change in thickness of a wave plate layer in a contact lens according to an embodiment of the present invention.
12 is a diagram showing the number of foci formed after incident light passes through a wave plate layer according to an embodiment of the present invention.
13A to 13F are diagrams illustrating various embodiments in which the waveplate layer of the present invention is disposed on a contact lens.

Hereinafter, a contact lens made of a multilayer wave plate according to a preferred embodiment will be described in detail with reference to the accompanying drawings. Here, the same reference numerals are used for the same components, and repeated descriptions and detailed descriptions of known functions and configurations that may unnecessarily obscure the subject matter of the invention are omitted. Embodiments of the invention are provided to more completely explain the present invention to those skilled in the art. Accordingly, the shapes and sizes of elements in the drawings may be exaggerated for clarity.

1 is a view showing the overall configuration of a contact lens made of a multi-layered wave plate according to an embodiment of the present invention, and FIGS. 2 and 3 show the structure of a contact lens made of a multi-layered wave plate according to an embodiment of the present invention. is the drawing shown.

Referring to FIGS. 1 to 3 , a contact lens made of a multilayer wave plate according to an embodiment of the present invention includes a corneal protective layer 10 , a wave plate layer 20 and a lens surface layer 30 .

The corneal protective layer 10 is configured to directly contact the eyeball when worn on the eyeball. Therefore, the corneal protective layer 10 has a convex shape with a substantially constant curvature according to the shape of the eyeball. The size or thickness of the corneal protective layer 10 may be variously set according to a designer's intention.

The lens surface layer 30 is configured to be exposed to the outside when worn on the eyeball. The lens surface layer 30 is formed to have a certain thickness to determine the dioptric power of the eye. The lens surface layer 30 has a convex shape with a substantially constant curvature, and is preferably formed as a smooth surface for natural contact with the eyelid when worn.

In the wave plate layer 20, two or more wave plates 21, 22, and 23 are stacked and disposed between the corneal protective layer 10 and the lens surface layer 30. The wave plate layer 20 may include a total of m (m≧2) wave plates from the first wave plate 21 to the last wave plate 23 . Although three or more wave plates are shown as being stacked in FIG. 1, as described above, two or more wave plates are stacked.

The wave plates 21, 22, and 23 are optical elements that change the polarization state of light, and are a waveplate lens (WL) made of a birefringent material. The wave plate 200 is also called a phase retardation plate. The polarization direction is referred to as the slow axis. The phase retardation plate includes a half wave plate (HWP), which is a λ/2 phase delay plate, and a quarter wave plate (QWP), which is a λ/4 phase retardation plate. For example, when a linearly polarized beam passes at an angle of θ with the fast axis of the HWP, it is rotated by 2θ and polarized, and when the linearly polarized beam passes at an angle of 45 degrees with the fast axis of the QWP, circularly polarized light is emitted. Polarization conversion technology of a linearly polarized or circularly polarized beam passing through HWP and QWP is a well-known technology, and a detailed description thereof is omitted herein.

4 is a view showing a cross section of a conventional diffractive lens.

On the other hand, according to the diffractive lens, generally known as a Fresnel lens, as shown in FIG. 4, it has a sawtooth shape as the radius increases from the center of the diffractive lens, and according to the size of the radius, Equation 1 below have the same phase distribution.

<Equation 1>

Here, r _j represents the j-th radius based on the center of the diffractive lens, λ is the wavelength length of the incident light, and F is the center focal length of the diffractive lens.

In addition, in the phase distribution of Equation 1, as the distance from the diffractive lens increases, several focal points are formed as shown in Equation 2 below.

< Equation 2 >

Here, m is the diffraction order of the diffractive lens.

Unlike the shape of the Fresnel lens described above, the wave plates 21, 22, and 23 according to the present invention are formed in an annular shape and manufactured to have a certain thickness according to the distance from the center of the wave plates 21, 22, and 23. It can perform the function of a Fresnel lens. At this time, when the incident light has left-handed circular polarization (LHCP) or right-handed circular polarization (RHCP), the arrangement direction of the fast axis and the slow axis of the wave plate according to the present invention is adjusted by adjusting the above equation A phase distribution with multifocality similar to Equation 1 and Equation 2 may be formed.

The wave plates 21, 22, and 23 according to an embodiment of the present invention are transparent materials, and may be composed of an anisotropic material such as a liquid crystal or, more generally, a reactive mesogen. can The thickness of the wave plates 21 , 22 , and 23 may be less than, equal to, or greater than the wavelength of the incident light 100 .

Regarding the manufacturing method of the wave plates 21, 22, and 23 according to an embodiment of the present invention, a previous research paper "J-H. Kim et al. "Fabrication of ideal geometric-phase holograms with arbitrary wavefronts", Optica Vol. 2 , No. 11, Nov. (2015)". According to the preceding research paper, the wave plates 21, 22, and 23 are manufactured by forming patterns for controlling optical axis rotation at their local positions. Here, as a method for patterning the rotation of the optical axis of the anisotropic material constituting the wave plates 21, 22, and 23, a rubbing method and an incident method of forming fine valleys on the surface of the wave plates 21, 22, and 23 by a mechanical method There is a photo-alignment method in which light is arranged in a certain direction according to the polarization of light.

Meanwhile, in the wave plate layer 20 , odd-numbered wave plates (eg, the first wave plate 21 ) and even-numbered wave plates (eg, the second wave plate 22 ) are disposed adjacent to each other. When the incident light 100 passes through the last wave plate 23 of the present invention, multifocal points 40 are formed. As shown in FIG. 1 , the multi-focal point 40 may include a total of n focal points from the first focal point 41 to the last focal point 43 . The number of focal points formed according to an embodiment of the present invention will be described later.

5 is a diagram illustrating a phase distribution of a wave plate according to an embodiment of the present invention.

The phase distribution of the wave plates 21, 22 and 23 of the present invention will be examined. FIG. 5 shows a phase distribution representing a phase difference of a light ray passing through a position separated by a radius r from the center of an optical axis (a point where r=0) in a transmitted wavefront incident on a wave plate. The retardation distribution shown in Fig. 5 is within the wavelength range of the incident light and has a sawtooth cross section.

The graph (a) of FIG. 5 is the phase distribution shown in odd-numbered wave plates, and the graph (b) in FIG. 5 shows the phase distribution shown in even-numbered wave plates. Looking at the phase distribution, a point appears where the phase changes rapidly (from +π to -π or from -π to +π) as the radius increases. In FIG. 5 , points where the phase changes abruptly in the phase distribution of odd-numbered waveplates are represented by P1 to Pn, and points where the phase changes abruptly in the phase distribution of even-numbered waveplates are represented by P1' to Pn'. The phase position Pn corresponds to the position of r _j in Equation 1 above. Here, the phase interval from the center (r = 0) to P1 is referred to as the X1 interval, and the phase interval from the center (r = 0) to P1' is referred to as the X1' interval. Although not shown in FIG. 3, phase intervals from the center (r = 0) to P2 and P2 are referred to as X2 and X2' intervals, respectively, and subsequent phase intervals may be displayed in the above-described manner. In this specification, the phase period from X1 thereafter and the phase period from X1 thereafter are collectively referred to as the X period.

Referring back to FIG. 5 , looking at the phase distribution according to an embodiment of the present invention, the phase of odd-numbered wave plates increases while the phase of even-numbered wave plates decreases in the same phase period (X). That is, the phase sign (+Φ) of the odd-numbered waveplate and the phase sign (-Φ) of the even-numbered waveplate must be opposite to each other. In this specification, this relationship is called a complementary relation. At this time, the value (absolute value) of the phase size may be the same or different.

Here, if the wave plates 21, 22, and 23 are manufactured so that the interval of the X section is different, the position where the focal point is formed can be adjusted. Specifically, referring to FIG. 5 and Equation 1, when one of the wave plates 21, 22, and 23 is manufactured, a phase value and a phase position (Pn or r _j ) within the range of -π to +π are determined. When the wave plates 21, 22, and 23 are manufactured such that the interval between the , X sections is changed, the focal length (F in Equation 1) is also changed while the phase position (Pn or r _j ) is changed. For example, if the interval of the X section decreases, the focal length also decreases.

Meanwhile, according to another embodiment of the present invention, in the same phase period (X), the phase of the odd-numbered lens waveplate may decrease and the phase of the even-numbered lens waveplate may increase.

The wave plate layer 20 may have a convex shape with a certain curvature so as to be naturally disposed on the corneal protective layer 10 and the lens surface layer 30 .

On the other hand, the total number of stacked wave plates, the curvature of the surface of the corneal protective layer 10 and the lens surface layer 30, the distribution of birefringent refractive index of each wave plate, etc., together with other lenses of the user's visual system, refraction correction necessary for distance and near vision. It can be changed in various ways to achieve.

Hereinafter, in order to investigate the effect of the contact lens made of the multilayer waveplate according to the present invention, the case where one waveplate is disposed and the case where the waveplates whose phase distribution is not mutually complementary are disposed adjacent to each other are the multilayer wavelength plates according to the present invention. It is explained in comparison with a contact lens made of a plate.

FIG. 6 is a view showing a state in which one wave plate is disposed on a contact lens, and FIG. 7 is a view showing positions of focal points and light intensity distribution according to a change in the thickness of the wave plate in FIG. 6 .

6 and 7, when only one wave plate 20' is disposed between the corneal protective layer 10 and the lens surface layer 30, linear polarized light 100 is incident. Then, three focal points 41', 42', and 43' are formed. As shown in FIG. 7, when the thickness (h) of the wave plate is λ/2, λ/3, and λ/4, the light intensity at each focal point appears. As such, in the case of a contact lens in which only one wave plate 20' is disposed, the total number of focal points is limited to a maximum of three. On the other hand, when the thickness (h) of the wave plate is changed, it can be seen that the light intensity at each focal position is changed.

8 is a view showing a state in which two wave plates that are not in a mutually complementary relationship are stacked and disposed on a contact lens, and FIG. 9 is a view showing positions of focal points and light intensity distribution when each thickness of the wave plates in FIG. 8 is λ/4. is a drawing showing

Referring to FIGS. 8 and 9 , a first wave plate 21" and a second wave plate 22" are stacked and disposed between the corneal protective layer 10 and the lens surface layer 30. Here, the first wave plate 21" and the second wave plate 22" are disposed adjacent to each other, but the phase distributions of the respective wave plates 21" and 22" do not complement each other. And, when the thickness of each wave plate is λ/4, the overall total thickness is λ/2. This is a case where the thickness of the wave plate is λ/2, and the total number of foci is limited to a maximum of 3 (see (a) of FIG. 7).

When a plurality of wave plates 21" and 22" that do not complement each other are disposed in the contact lens, the maximum number of foci can be obtained as shown in Equation 3 below.

< Equation 3 >

Here, N is the maximum number of foci and m is the number of waveplates.

In addition, Equation 3 above may be applied even when one wave plate is disposed on the contact lens.

10 is a view showing a state in which multiple focal points are formed when two wave plates whose phases are complementary to each other are stacked and disposed in a contact lens according to an embodiment of the present invention, and FIG. 11 is a view showing a contact lens according to an embodiment of the present invention. It is a diagram showing the change in light intensity at each focal position according to the change in the thickness of the wave plate layer in the lens.

10 and 11, two wave plates 21 and 22 are stacked on a contact lens. Here, the first wave plate 21 and the second wave plate 22 are disposed adjacent to each other, and the phase distributions of the respective wave plates 21 and 22 are complementary to each other. And, when the thickness of each wave plate is λ/4, the overall total thickness is λ/2. The number of foci formed by these multifocal lenses is at most seven.

In this way, when a plurality of wave plates complementary to each other are disposed in the contact lens, the effect of increasing the number of maximum foci occurs.

Meanwhile, as described above, when the first wave plate 21 and the second wave plate 22 have a mutually complementary relationship, the magnitude of the phase may be different. Here, if the size of the phase is different, the value of light intensity may vary without changing the number of focal points.

When a plurality of wave plates in a mutually complementary relationship are disposed in the contact lens, the maximum number of foci can be obtained as shown in Equation 4 below.

<Equation 4>

Here, N is the maximum number of foci and m is the number of waveplates.

11 is a view showing a change in light intensity at each focal position according to a change in thickness of a wave plate layer in a contact lens according to an embodiment of the present invention.

The value calculated by Equation 4 is the maximum number of focal points. If the thickness of the wave plate is adjusted, that is, the light intensity at each focal point is adjusted, it is possible to adjust the number of focal points within the limit of the maximum number of focal points. . For example, when seven focal points are formed according to the multifocal lens of the present invention, if the light intensity at at least one focal position is set to 0 by adjusting the thickness of at least one wave plate, the focal point at that position is It is possible to reduce the total number of focus points, since the same effect as disappearing can be obtained.

FIG. 11 shows a change in light intensity at each focus position as the thickness h of the wave plate increases from 0 to λ when five focus points 41, 42, 43, 44, and 45 are formed. For example, when the thickness (h) of the wave plate is λ/4, the light intensities at the positions of the three focal points 42, 43, and 44 are almost the same, and the thickness (h) of the wave plate is 3λ/4. Light intensities at the positions of the three focal points 42, 43 and 45 are almost the same. Accordingly, when the thickness (h) of each wave plate is adjusted from 0 to λ or more than λ, the light intensity distribution between focal points can be adjusted.

12 is a diagram showing the number of focal points formed after incident light passes through a wave plate layer according to an embodiment of the present invention.

As shown in FIG. 12, the number of foci formed according to the number of layers of the wave plate is a value calculated by Equation 4 above.

Meanwhile, a method of predicting the light intensity at the focal position is as follows. Specifically, when right-circularly polarized light or left-circularly polarized light is incident on the wave plate 200, the conversion efficiency to polarized light in the opposite direction can be obtained as shown in Equation 5 below.

<Equation 5>

로서, 위상 지연(입사광의 위상 변화)를 의미한다.

는 입사광의 파장이고,

파장판의 복굴절률이며,

는 파장판의 두께이다.here,

As , it means phase retardation (phase change of incident light).

is the wavelength of the incident light,

is the birefringence of the wave plate,

is the thickness of the wave plate.

Incident light that is linearly polarized has the same ratio of right circularly polarized light and left circularly polarized light. When linearly polarized light is incident on the wave plate, the direction of the circularly polarized light included in the incident light is changed. For example, right circularly polarized light included in linear polarized light is changed to left circularly polarized light. That is, as the linearly polarized light passes through the wave plate, the left circularly polarized light and the right circularly polarized light have opposite signs and experience a geometric phase delay. At this time, the remaining light that is not converted while passing through the wave plate passes through the wave plate with linear polarization without being affected by the geometric phase delay. Equation 5 is the efficiency of passing through the wave plate without being polarized (referred to as polarization conversion efficiency), and the light intensity at each focal point is affected by the polarization conversion efficiency. Here, it can be seen that the polarization conversion efficiency varies depending on the thickness of the wave plate.

Even when a plurality of wave plates are disposed, the light intensity at each focal point can be sufficiently predicted using Equation 5 above.

Meanwhile, a method for determining a focal position when a wave plate layer is disposed on a contact lens is as follows. Reference is made again to FIGS. 6 and 7 for explanation. As shown in FIG. 6, when there is one wave plate 20', the number of foci is three (F-1, F-2, F-3) according to Equation 3 (or Equation 4) above. . On the other hand, if the thickness of the wave plate 20' is a half-wavelength phase delay, since linear polarization is not generated, there are two focal points (see (a) of FIG. 7).

Each focal position can be obtained as shown in Equation 6 below.

<Equation 6>

는 파장판을 통과한 후 각 초점 위치에서의 초점 거리이고,

은 굴절렌즈의 초점 거리이며,

는 파장판의 초점 거리를 의미한다.here,

is the focal length at each focal position after passing through the wave plate,

is the focal length of the refractive lens,

is the focal length of the waveplate.

)와 관련하여, 상술한 바에 따르면 입사광이 원편광인 경우 파장판을 통과하면 위상 지연을 겪으면서 부호가 바뀐다. 따라서, 우원편광에 의한 초점 거리가

라면 좌원편광에 의한 초점 거리는

이다. 좌원편광과 우원편광이 파장판을 통과하는 경우 서로 반대 부호를 가진 원편광으로 변환되므로 이는 파장판이 어느 하나의 원편광에 대해서는 볼록렌즈처럼 기능하고 다른 하나의 원편광에 대해서는 오목렌즈처럼 기능한다. 한편, 입사광이 선형편광이라면 초점 거리는 무한대이다.The focal length of the waveplate (

), according to the foregoing, when the incident light is circularly polarized, the sign is changed while undergoing a phase delay when passing through the wave plate. Therefore, the focal length by right circular polarization is

If , the focal length due to left circular polarization is

am. When left circularly polarized light and right circularly polarized light pass through a waveplate, they are converted into circularly polarized light with opposite signs, so the waveplate functions like a convex lens for one circularly polarized light and a concave lens for the other circularly polarized light. On the other hand, if the incident light is linearly polarized, the focal length is infinite.

를 더 합하여 각 초점 거리를 구할 수 있다. 이때, 증가되는 초점의 개수는 상기 수학식 4에 의해 구할 수 있다. 이를 일반화하면 아래 수학식 7과 같다.Equation 6 is a formula for obtaining three focal lengths by one wave plate. However, when a plurality of wave plates are disposed, each focal distance formed by the wave plates can be calculated by repeating Equation 6 as many times as the number of wave plates. Specifically, when one more wave plate is increased in the state of FIG. 6, the right side of Equation 6

By further summing , each focal length can be obtained. At this time, the increased number of focal points can be obtained by Equation 4 above. Generalizing this, Equation 7 below is obtained.

<Equation 7>

은 마지막 파장판을 통과한 후의 초점 거리이고,

은 각 파장판의 초점 거리이다.here,

is the focal length after passing through the last wave plate,

is the focal length of each waveplate.

In summary, the contact lens made of multilayer waveplates according to the present invention can change the number of focal points by adjusting the thickness of the waveplates when the phase distribution between adjacent waveplates satisfies a mutually complementary relationship, and each wavelength The position of the focal point can be changed by adjusting the phase distribution of the plate (see Equations 1 and 7). In this case, the adjusted focus may be classified into a short-range focus, a middle-range focus, and a long-range focus according to settings. Therefore, according to the present invention, it is possible to form various focal points according to the visual acuity condition of the contact lens user and the purpose of use.

On the other hand, if the wave plate layer 20 according to the present invention is disposed on the contact lens, when the incident light passes through the contact lens, multiple layers spatially generated along the diameter distance of the contact lens away from the last wave plate in the Z-axis direction. The light intensity distribution of the foci is shown. That is, the focal points formed through the contact lens according to the present invention can be created spatially as well as in the Z-axis direction.

13A to 13F are diagrams illustrating various embodiments in which the waveplate layer of the present invention is disposed on a contact lens.

In the contact lens composed of multilayer wave plates according to the present invention, a wave plate layer 20 satisfying a mutually complementary relationship is disposed between the corneal protective layer 10 and the lens surface layer 30. At this time, the wave plate layer 20 considers various conditions such as the surrounding environment of the contact lens wearer (eg, indoors or outdoors), the user's eye condition (eg, farsightedness or nearsightedness), and a change in pupil size. It may be disposed on the corneal protective layer 10 in a suitable form.

Meanwhile, the corneal protective layer 10 may be divided into a central region, which is a central portion, and a peripheral region, which is a peripheral portion thereof. Here, the area of the central region may be variously set according to the designer's intention. The wave plate layer 20 may have various shapes (eg, circular, elliptical, polygonal, annular, etc.) and numbers, and may be disposed in the central region or the peripheral region.

In the embodiment shown in FIGS. 13A to 13C , the wave plate layer 20 is basically disposed in the central region of the corneal protective layer 10 . This embodiment may be suitable when the contact lens wearer is outdoors.

In the embodiment shown in FIG. 13A, the wave plate layer 20 is formed in a substantially circular shape and disposed only in the central region of the corneal protective layer 10. At this time, the area of the wave plate layer 20 is smaller than that of the corneal protective layer 10 .

In the embodiment shown in FIG. 13B, one wave plate layer 20 is disposed in the central region, and is formed in an annular shape with a constant thickness to surround the central region, and is spaced apart from the central region by a predetermined distance in the radial direction. 1 is placed in the area.

In the embodiment shown in FIG. 13C, one wave plate layer 20 is disposed in the central region, and is formed in an annular shape with a constant thickness so as to surround the central region, and has different radii in a radial direction in the central region. Two are placed in the peripheral area spaced apart from each other by a certain distance.

In the embodiment shown in FIGS. 13D to 13F , the wave plate layer 20 is basically disposed in the peripheral area except for the central area of the corneal protective layer 10 . This embodiment may be suitable when the contact lens wearer is indoors.

In the embodiment shown in FIG. 13D , the wave plate layer 20 is formed in an annular shape with a constant thickness so as to surround the circumference of the corneal protective layer 10 and is disposed in the peripheral region of the corneal protective layer 10 .

In the embodiment shown in FIG. 13E, the wave plate layer 20 is formed in an annular shape having a constant thickness while having a size smaller than that of the corneal protective layer 10, and is formed in the peripheral region except for the central region of the corneal protective layer 10. 1 is placed

In the embodiment shown in FIG. 13F, the wave plate layer 20 is formed in an annular shape with a constant thickness, and one wave plate layer 20 is disposed in the first peripheral area excluding the central area, and is formed in an annular shape with a constant thickness to form a first peripheral area. One is disposed in the second peripheral area spaced apart from the first peripheral area by a predetermined distance while enclosing the area.

However, the present invention is not limited to the embodiments shown in FIGS. 13A to 13F. As described above, the wave plate layer 20 disposed in the central region may have various shapes such as a circular shape, an elliptical shape, and a polygonal shape. In addition, the wave plate layer 20 disposed in the peripheral area may have a semi-circular shape spaced apart by a predetermined distance in the outer direction of the central area, a shape having the same radius and disposed at a predetermined interval in the circumferential direction, and the like.

Meanwhile, in the present invention, the total number of wave plates, the curvature of the surface of the refracting lens, and the distribution of the refractive index of each wave plate may be variously changed to achieve refractive compensation required for distance and near vision together with other lenses of the visual system. there is. In addition, the wave plate layer 20 may be disposed on the entire area or a partial area of the corneal protective layer 10 .

The present invention has been described with reference to an embodiment shown in the accompanying drawings, but this is only exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. You will be able to. Therefore, the true protection scope of the present invention should be defined only by the appended claims.

10: corneal protective layer 20: wave plate layer
30: lens surface layer 40: multifocal
100: incident light

Claims (18)

lens surface layer;
corneal protective layer; and
A wave plate layer in which two or more wave plates made of a birefringent material are stacked and disposed between the lens surface layer and the cornea protective layer;
A contact lens made of multi-layered waveplates, characterized in that the phase codes of the waveplates adjacent to each other in the waveplate layer are opposite to each other so that the phases are complementary to each other. According to claim 1,
A contact lens made of multi-layered wave plates, characterized in that when the thickness of one or more wave plates in the wave plate layer is changed, the light intensity at the focal point is changed accordingly. According to claim 2,
A contact lens made of a multi-layered wave plate, characterized in that the number of the focal points changes when the thickness of the wave plate layer is adjusted so that the light intensity at a position where one of the focal points is formed becomes 0. According to claim 1,
A contact lens made of a multi-layer wave plate, characterized in that the number of foci generated by the wave plate layer is calculated by Equation 1 below.
<Equation 1>

Here, N is the maximum number of foci and m is the number of waveplates. According to claim 1,
A contact lens made of a multi-layer wave plate, characterized in that the position of the focal point created by the wave plate layer is calculated as in Equation 2 below according to the number of the wave plate.
< Equation 2 >

here,

is the focal length after passing through the last wave plate,

is the focal length of each waveplate. According to claim 1,
A contact lens made of a multi-layered wave plate, characterized in that when the phase section (X) between points where the phase changes rapidly at the center of the wave plate layer changes, the position where the focus is formed changes accordingly. According to claim 1,
In the same phase period (X) between first and second wave plates adjacent to each other in the wave plate layer, when the phase in the first wave plate increases, the phase in the second wave plate decreases. A contact lens made of waveplates. According to claim 1,
The contact lens made of a multi-layered wave plate, characterized in that the wave plate layer is disposed in the central region of the corneal protective layer. According to claim 8,
The contact lens made of a multi-layered wave plate, characterized in that the wave plate layer disposed in the central region has a smaller area than the cornea protective layer. According to claim 1,
One of the wave plate layers is disposed in the central region of the corneal protective layer, and the other wave plate layer is disposed in a peripheral region excluding the central region and spaced apart from the central region by a predetermined distance in an outward direction of the central region. A contact lens made of a multi-layer wave plate. According to claim 10,
A contact lens made of a multi-layered wave plate, characterized in that the wave plate layer disposed in the peripheral region is formed in an annular shape with a constant thickness. According to claim 10,
A contact lens made of a multi-layered wave plate, characterized in that a plurality of wave plate layers disposed in the peripheral region are formed in an annular shape with a constant thickness, have different radii, and are spaced apart from adjacent wave plate layers by a predetermined distance. According to claim 1,
The contact lens made of a multi-layered wave plate, characterized in that the wave plate layer is disposed in the peripheral region except for the central region of the corneal protective layer. According to claim 13,
The contact lens made of a multi-layered wave plate, characterized in that the wave plate layer is formed to surround the circumference of the corneal protective layer. According to claim 13,
The contact lens made of a multi-layered wave plate, characterized in that the wave plate layer is formed inside the corneal protective layer. According to claim 13,
A contact lens made of a multi-layer wave plate, characterized in that the wave plate layer is formed in an annular shape with a constant thickness. According to claim 1,
One of the wave plate layers is disposed in a first peripheral region excluding the central region of the corneal protection layer, and another wave plate layer is a second wave plate layer spaced apart from the first peripheral region by a predetermined distance in an outer direction of the first peripheral region. A contact lens made of a multilayer wave plate, characterized in that it is disposed in the peripheral area. 18. The method of claim 17,
A contact lens made of a multi-layered wave plate, characterized in that a plurality of wave plate layers disposed in the second peripheral region are formed in an annular shape with a constant thickness, have different radii, and are spaced apart from adjacent wave plate layers by a predetermined distance.

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