RU2821443C2 - Spiral dioptric device with meridians of different optical power - Google Patents

Abstract

FIELD: optics.

SUBSTANCE: invention relates to optical instrument making and relates to an optical device. Optical device has an optical axis and comprises at least one surface with at least two meridians, at least one part of which, when viewed from the front, forms at least one spiral segment, the central point of which is located on the optical axis. Each spiral segment defines meridians with different optical power so that the obtained focus is distributed along the tubular area.

EFFECT: increased length of the focal region.

15 cl, 14 dwg

Description

Field of technology to which the invention relates

The present invention relates to the field of optical devices that form diopter interfaces.

Although the invention is described with reference to an ophthalmic lens application, it is applicable to any spherical or toric dioptric interface and to any dioptric interface the surface of which has at least two meridians that can be used to form an image and/or distribute optical power and/or vision correction.

Thus, the optical device according to the invention may be an optical lens of an optical system, a spectacle lens or a rigid or flexible contact lens, a photographic lens part, a motion detector part, or a light energy concentration device.

Generally, the invention is applicable to any application in which light is focused into a visible or invisible region.

State of the art

A lens, such as an ophthalmic lens, contains two opposing optical surfaces, called diopter interfaces, connected by an end surface that is typically fitted into a cylinder with a circular base.

Currently, optical surfaces are generally classified into four distinct categories, namely:

- spherical diopter interfaces, the surface of which is part of the inner or outer surface of the sphere;

- aspherical diopter interfaces obtained from spherical surfaces, the surface of which is part of a surface of rotation, the curvature of which continuously changes from the apex to the periphery;

- toric diopter interfaces, the surface of which has two orthogonal principal meridians of unequal curvature and the cross-section of which along these two meridians is nominally circular;

- atoric diopter interfaces, the surface of which has two main meridians, mutually perpendicular and unequal curvature, and the cross-section of at least one of the main meridians is not circular.

The focal point of a spherical lens formed by combining two spherical diopter interfaces has one focal length to a point called the focal point of the image. This point focus is characteristic of the so-called “stigmatic” optical system.

With reference to FIG. 1, the well-known principle of astigmatism (the absence of single-point stigmatism obtained with a spherical lens) created by an optical lens having a toric surface 1 will be recalled.

The toric surface 1 has a first meridian 2 curved with a first curvature C1 about the axis of rotation of the torus (not shown in the drawing), so that the first meridian 2 forms a circular arc of the first circle formed by the outer radius of the torus.

The toric surface 1 also has a second meridian 3, perpendicular to the first meridian 1 and curved with a second curvature C2, which is greater than the first curvature, around a center of curvature located at the radius of the torus that passes through the middle of the first meridian 2 - indicated by the reference numeral AA. The A-A axis is the optical axis of the toric surface.

The lens is made of an optical material with a refractive index n, so that light passing through said toric surface 1 is refracted.

In particular, in parallel illumination, light passing through the first meridian 2 converges at the first focal length 4, thereby forming a section 5 parallel to the first meridian 2, and light passing through the second meridian 3 converges at the second focal length 6, thereby forming a section 7 parallel to the second meridian 3.

Toric lens 1 has two optical powers D1 and D2, which are determined by the following relations: D1=(n-1)C1 and D2=(n-1)C2.

US Pat. No. 5,198,844 discloses a multifocal lens divided into a plurality of alternating sections that have at least two different refractive powers. In one embodiment, the boundaries between successive regions are arcs starting from the center of the lens. This lens consists solely of spherical or aspherical sections, these sections also having surface connections in the form of fins.

Basically, there is a need to improve the so-called stigmatic optical devices with a spherical surface in order to lengthen their focal area.

One object of the invention is to at least partially satisfy this need.

Disclosure of the invention

To this end, the invention relates, according to one aspect, to an optical device having an optical axis comprising at least one surface with at least two meridians, at least one part of which forms, when viewed from the front, at least one spiral segment, a central the point of which is on the optical axis, each spiral segment defining meridians of different optical powers, so that the focus is no longer simply a single point stigmatic, but spreads over a tubular region extended along the optical axis.

By “viewed from the front,” here and in the context of the invention, is meant a view of the device along the optical axis. In other words, we are talking about a view in projection onto a plane orthogonal to the optical axis.

For clarity, the spiral-shaped portion of the surface is defined in projection onto a plane orthogonal to the optical axis. Since the helical segment according to the invention develops on a three-dimensional surface, it is a helix.

Thus, the invention essentially consists of creating, from a surface with two or more diopter interface meridians, a surface containing at least one helix segment, i.e. spiral surface in projection onto a plane orthogonal to the optical axis.

In other words, the invention essentially consists of providing a diopter interface having a helical surface with two meridians.

In a sense, if a surface with two or more meridians were in a pliable state, it could be deformed by torsion along one or more spiral curves.

This spiralization can be applied to any non-spherical diopter interface surface that has more than two meridians.

Spiralization is preferably carried out on a toric surface and more preferably on an optical device containing two concentric tori with meridians located in opposite directions, i.e. at an angle of 90° to each other.

In the case of a toric surface, this allows light to propagate along the curvature of the first meridian to the first focal length, and light to propagate along the curvature of the second meridian to the second focal length, while the spiralization of the astigmatism axes leads to the creation of a spiral-shaped focal light tube and, thus, to increasing the focal length of the diopter interface.

The spiral segment according to the invention can have different shapes, for example according to a linear law, a quadratic law or a substantially logarithmic law. These different laws may also be combined on the same surface of the optical device, for example, to produce a lens with a logarithmic law in a first annular lens segment and a quadratic or linear law in a second annular lens segment surrounding the first annular segment.

The spiral segment according to the invention can be created in only one part of the diopter interface. Thus, it can be created only in the central part, in the part connecting two separate surfaces, for example two toric surfaces, or in the peripheral part.

The tubular focus obtained according to the invention is a focus that remains unchanged over an extended range of focal lengths and is inscribed in a tube.

The invention has many advantages, among which are:

- the ability to reduce the need to adjust focus in any optical imaging system, such as a photographic lens, camera, projector lens, virtual reality headset, etc.;

- the ability to reduce the volume of the optical imaging system, for example, by eliminating the currently used motorized focusing devices;

- the possibility of its use in optical force concentration systems, such as solar heating systems or laser cutting devices. For example, in a laser cutting device, a tubular focus allows the length of the focal region along the optical axis to be increased and thus the thickness that can be cut to be increased;

- the possibility of its use in optical detection systems, such as infrared motion detectors or physical measurement systems, the length of the field of focus due to the tubular focus advantageously reduces the need for focus adjustment;

- in vision correction applications, the tubular focus allows you to create a field of focus over a large range of focal lengths, for example, to provide near and far vision with a single ophthalmic lens and provide optical compensation for presbyopia and a number of ametropias. Thus, one ophthalmic lens can be used for more than one ametropia value. The tube focus also allows for better off-axis focusing of beams to improve the field of view. This may find particularly good use in ophthalmic lenses. An optical lens, one surface of which is formed by spiralization according to the invention, makes it possible, in particular, to lengthen the caustics of focal lengths.

In general, the optical device embodying the invention can be used in any imaging application, such as photography, video, optical detection, vision correction, and any other application requiring focusing.

The optical device, in particular the lens, can be made from any optical material such as optical glass or polymer.

One or more helical segments according to the invention can be manufactured using machining, additive manufacturing or molding technologies, or using a combination of several of these technologies.

According to one preferred embodiment, one or more helical segments are formed from a toric surface having a first meridian curved with a first non-zero curvature and a second meridian curved with a second curvature that is strictly greater than the first curvature, the second meridian being perpendicular to the first meridian.

According to this embodiment and one preferred embodiment, one or more helical segments are formed from first and second toric surfaces, the first toric surface having a first meridian curved with a first non-zero curvature about the axis of rotation of the first torus, and a second meridian curved with a second curvature, which is strictly greater than the first curvature, and the second meridian is perpendicular to the first meridian, and the second toric surface has a first meridian curved with a first non-zero curvature around the axis of rotation of the second torus, and a second meridian curved with a second curvature that is strictly greater than the first curvature, and perpendicular to the first meridian of the second toric surface,

wherein the first and second toric surfaces each contain a plurality of azimuthal angular sectors located around the optical axis,

the first meridian of the first toric surface and the first meridian of the second toric surface have azimuthal orientations separated by a non-zero angle relative to the optical axis,

the spiral segments define the first and second meridians of optical power, obtained from the first meridian of the first toric surface and from the first meridian of the second toric surface.

In one embodiment, the azimuthal angular sector of the first toric surface and the azimuthal angular sector of the second toric surface are adjacent across a spiral segment boundary.

The first and second toric surfaces may each contain two diametrically opposed azimuthal angular sectors.

Each corner sector of the first toric surface can be adjacent to two corner sectors of the second toric surface.

According to one preferred feature, the angle between the azimuthal orientations of the first meridian of the first toric surface and the first meridian of the second toric surface is from 60° to 90°.

Preferably, the first curvature of the first toric surface is equal to the first curvature of the second toric surface.

More preferably, the second curvature of the first toric surface is equal to the second curvature of the second toric surface.

In one embodiment, the radius of the helical segment is related in polar coordinates to the angle of the helix according to a linear law, a quadratic law, or a logarithmic law.

According to another embodiment, the optical device further includes a spherical surface centered on the optical axis.

The optical device according to the invention may preferably form an optical lens, the front side of which is a surface with at least one helical segment.

Another object of the invention is the use of the optical device just described for vision correction and/or light power concentration and/or image formation.

Brief description of drawings

Other advantages and features of the invention will become more apparent upon reading the detailed but non-limiting description of examples of embodiments of the invention, which are given by way of illustration with reference to the following drawings, in which:

- fig. 1 is a schematic representation of the distribution of a parallel beam of light passing through an optical lens of a toric surface;

- fig. 2 is a schematic front view of a first embodiment of a tubular focus optical lens;

- fig. 3 is a schematic front view of a multifocal optical lens with two toric surfaces axially opposed to each other;

- fig. 4 is a schematic perspective view of the multifocal optical lens of FIG. 3;

- fig. 5 is a schematic view of the distribution of a parallel beam of light passing through the optical lens of FIG. 3 and 4;

- fig. 6 is a schematic front view of a multifocal optical lens with two toric surfaces axially opposed to each other;

- fig. 7 is a schematic front view of an embodiment of a tubular focus lens according to the invention formed from the geometry of the lens of FIG. 6;

- fig. 8 is a schematic front view of another embodiment of a multifocal optical lens with two toric surfaces axially opposed to each other;

- fig. 9 is a schematic front view of another embodiment of a tubular focus lens according to the invention, formed from the geometry of the lens of FIG. 8;

- fig. 10 is a schematic side view of the distribution of a parallel light beam of light passing through an optical lens according to the invention and, in comparison, a spherical optical lens according to the prior art;

- fig. 11 is a schematic perspective view of a beam of parallel light rays passing through an optical lens according to the invention with logarithmic spirals, FIG. 11 shows a tubular light beam focusing area;

- fig. 12 is an enlarged view of the light beam focus tube of FIG. 11 and compares the focal area of the lens with toric surfaces located axially opposite each other, as shown in FIG. 6;

- fig. 13 is a front view of an embodiment of a tubular focus lens according to the invention comprising a spherical central portion and a helical peripheral portion;

- fig. 14 is a front view of another embodiment of a tubular focus lens according to the invention, comprising two toric surfaces and a helical connecting portion therebetween.

Carrying out the invention

Fig. 1, which relates to the prior art, has already been commented on in the introductory part. Therefore, it is not described in more detail below.

The following figures show a number of examples of optical lenses according to the invention containing surfaces with more than two meridians with at least one helical segment forming a focus extending along a tubular region.

As can be seen from the various figures, the spiralization segment can be obtained in various ways, for example, by a linear law, a quadratic law, or a substantially logarithmic law. These different laws can also be combined in the same lens, with a logarithmic law in the first annular lens segment and a quadratic or linear law in the second annular lens segment surrounding the first annular segment.

A given optical device may comprise a plurality of helical segments.

In fig. 2 shows a tubular focus optical lens 800 according to a first embodiment of the invention. The contrast representation used indicates a division perpendicular to the plane of the figure: darker means it is further away from the reader, and lighter means it is closer to the reader. The optical lens 800 is formed by spiralizing a toric lens surface as shown in FIG. 1. The center point is designated as 806. Thus, the geometry of the surface 801 is a spiral, the center point 806 of which is on the optical axis. In polar coordinates, the helix angle increases with radial distance from the optical axis. In particular, the first meridian 802 having a first curvature is further shaped like a spiral about the optical axis. In addition, lines 803 that have a second curvature and that would be parallel to the second meridian in the toric lens of FIG. 1, here they have different azimuthal orientations, with the orientation of the lines changing as they move away from the optical axis due to spiralization.

In fact, in order to carry out the invention, after analyzing the disadvantages of multifocal lenses of the prior art, the inventor sought to stretch the focal area along the optical axis.

Starting with multifocal lenses with two concentric toric surfaces, he then thought about positioning them axially opposite each other.

In fig. 3 and 4 show a front and perspective view of such a multifocal optical lens 100. The multifocal optical lens 100 includes a first toric surface 102 and a second toric surface 104 that concentrically surrounds the first surface 102.

Thus, when viewing the lens 100 in an axial direction along the optical axis A-A, a first surface 102 corresponds to a first optical region and a second surface 104 corresponds to a second optical region concentric with the first surface 102.

The first toric surface 102 has a first meridian 102 ₁ curved with a first curvature and a second meridian 102 ₂ curved with a second curvature and perpendicular to the first meridian 102 ₁ . Likewise, the second surface 104 has a first meridian 104 ₁ curved with a first curvature and a second meridian 104 ₂ curved with a second curvature and perpendicular to the first meridian 104 ₁ . Specifically, on each of the first and second surfaces 102, 104, the second curvature is greater than the first curvature.

The periphery of each of the first and second surfaces 102, 104 is a circular cross-section.

The first meridian 102 ₁ of the first surface 102 is perpendicular to the first meridian 104 ₁ of the first surface 104.

The first curvature of the first surface 102 may be different from or equal to the first curvature of the second surface 104. Likewise, the second curvature of the first surface 102 may be different from or equal to the second curvature of the second surface 104.

Thus, the lens 100 contains two concentric tori having different meridian axes, which in particular are located opposite each other or in a counter-axis format, that is, such that the angle between the two tori is 90°.

In fig. 5 shows the distribution of light transmitted through the multifocal optical lens 100 under parallel illumination in an example in which the first curvature of the first surface is equal to the first curvature of the second surface and in which the second curvature of the first surface is equal to the second curvature of the second surface. Light passing through the first meridian 102 ₁ of the first surface 102 converges at the first focal length 106, thereby forming a first portion 108 ₁ parallel to the first meridian 102 ₁ , and light passing through the second meridian 102 ₂ of the first surface 102 converges at the second focal length distance 110, forming a second section 108 ₂ , parallel to the second meridian 102 ₂ .

In addition, light passing through the first meridian 104 ₁ of the second surface 104 converges at the first focal length 106, thereby forming a first portion 112 ₁ parallel to the first meridian 104 ₁ , and light passing through the second meridian 104 ₂ of the second surface 104 converges at the second focal length 110, thereby forming a second section 112 ₂ parallel to the second meridian 104 ₂ .

Thus, with such a lens 100, the resulting focal area is longer than the focal areas of prior art multifocal lenses. This elongated focal region depends on the toricity of the surfaces 102, 104.

Noticing that this focal region was not sufficiently concentrated, the inventor then thought of spiralizing the surfaces to obtain a focus concentrated in a tubular region, thereby making it possible to obtain a focus at a longer distance along the optical axis.

Fig. 6 and 7 illustrate an embodiment of an optical lens 200 with a tubular focus and a double toric surface, axially opposed and helically opposed, respectively.

The optical lens 200 of FIG. 6 includes a first toric surface 202 having a first meridian 2021 curved with a first curvature about the axis of rotation of the first torus, and a second meridian (represented by an arc 202 ₂ parallel to the second meridian) that is curved with a second curvature that is greater than the first curvature and perpendicular to the first meridian 202 ₁ . The optical lens 200 also includes a second toric surface 204 adjacent the first toric surface 202 and having a first meridian 204 ₁ curved with a first curvature about the axis of rotation of the second torus, and a second meridian (represented by an arc 204 ₂ parallel to the second meridian) curved with second curvature and perpendicular to the first meridian 204 ₁ . When viewed from the front, that is, in projection onto a projection plane perpendicular to the optical axis of the lens 200 passing through its center 206, the first toric surface 202 corresponds to two azimuthal angular sectors 208 ₂ and 208 ₄ , diametrically opposed and intersecting at their vertices, which face center 206 of the optical lens 200. In the same way, the second toric surface 204 corresponds to two azimuthal angular sectors 208 ₁ and 208 ₃ that are diametrically opposed and intersect at their vertices, which face the center 206. Each azimuthal angular sector 208 ₂ and 208 ₄ of the first toric surface 202 is adjacent to two azimuthal angular sectors 208 ₁ and 208 ₃ of the second toric surface 204. The angular sectors 208 are limited by the points of intersection of the first toric surface 202 and the second toric surface 204, which represent the intersection lines in space of two cylindrical rings whose axes of rotation are perpendicular . These intersection lines are represented by boundaries 210 ₁ , 210 ₂ , 210 ₃ and 210 ₄ between azimuthal angular sectors 208 ₁ , 208 ₂ , 208 ₃ and 208 ₄ . In space, each of the boundaries 210 ₁ , 210 ₂ , 210 ₃ and 210 ₄ is shifted back in the direction of the optical axis relative to the first meridians 202 ₁ and 204 ₁ .

In fig. 7 shows an optical lens 200 obtained by spiralizing the toric surfaces of the lens in FIG. 6. Thus, the first meridian 202 ₁ of the first toric surface 202 and the first meridian 204 ₁ of the second toric surface 204 represent a spiral segment, the center point 206 of which is on the optical axis of the optical lens 200. Likewise, each of the boundaries 210 ₁ , 210 ₂ , 210 ₃ and 210 ₄ is a helical segment, the center point 206 of which is located on the optical axis of the optical lens 200.

Spiralization can be carried out in various ways, for example, according to a linear law, a quadratic law, or an essentially logarithmic law. To apply the logarithmic law, it is necessary to make a simplification near the center 206 of the lens, where the angle of the helix will mathematically diverge.

In the example shown in FIG. 7, the magnification angle reaches 45° at the periphery 25 of the optical lens 200. This angle can have a different value, for example, from 30° to 720° and, in particular, equal to 60°. The periphery 25 of the optical lens 200 here has a circular shape. This shape may be other than round.

Fig. 8 and 9 illustrate an embodiment of an optical lens 400 with a tubular focus and a double toric surface, axially opposed to each other and axially opposed to each other in a helical direction, respectively.

The tubular focus optical lens 400 of FIG. 8 is designed similarly to the optical lens 200 of FIG. 6, but with three separate azimuth sectors 401, 402 and 403 instead of four azimuth sectors. Each azimuthal sector 401, 402, 403 has a toric surface segment with corresponding first meridians 401 ₁ , 402 ₁ , 403 ₁ , which are oriented in different azimuthal directions at an angle of 120° to each other in a symmetrical case, as shown. The second meridians are not shown here, but in each case they are perpendicular to the corresponding first meridians. Azimuth sectors 401, 402, 403 are limited by boundaries 405.

In fig. 9 shows a lens 400 with a tubular focus formed from the surface of the lens of FIG. 8. Here the spiral segments obey the quadratic law of spiralization: the angle of the spiral is proportional to the square of the radial distance from the center 406 along the optical axis. Each of the boundaries 405 and each of the primary meridians 401 ₁ , 402 ₁ , 403 ₁ have the same spiral geometry. In the example shown, the helix angle reaches 360° at the periphery of the optical lens 400, i.e. one full revolution. A second full rotation could be made for a larger lens, i.e. with an angle of 720° or more.

As a numerical example, the tubular focus optical lens 400 of FIG. 9 with a front surface with four identical toric branches, the parameters of which are as follows:

- first curvature of a toric surface: focal length is 17.4 cm

- second curvature of the toric surface: focal length is 14 cm

- focuses are separated by 1.4 diopters

- spiral shape: logarithmic in the golden ratio

- spiral angle: 720°

- lens diameter: 10 mm

- other geometric parameters: the rear surface is spherical with a radius of curvature of 7.8 mm. The thickness at the center of the lens 400 is 0.5 mm.

In general, the tubular focus optical lens of the invention can be constructed similarly to one of the illustrated optical lenses 200, 400, 800 using any number of toric surfaces, each occupying one azimuthal angular sector. Thus, the number of toric arms distributed around the optical axis in the helical surface may be even (eg, 2 arms in optical lens 800, 4 arms in optical lens 200) or odd (eg, 3 arms in optical lens 400). Another number of branches is possible, for example 5, 6, 7 or more.

Moreover, the boundaries between adjacent toric surfaces can be sharp or smooth. For example, local curvature can be interpolated near boundaries to provide shallow transition regions between adjacent toric surfaces and thus limit extreme slopes.

The tubular focus obtained according to the invention is shown in FIG. 10 compares a spherical optical lens 1301 according to the prior art and a tubular focus optical lens 1302 according to the invention, each of the two lenses 1301, 1302 being intended for vision correction. As shown in FIG. 10, parallel illumination is incident on the lenses 1301 and 1302, where Z denotes the area of focus perceived by the human eye that is on either side of the focal point of the lenses. As can be very clearly seen from FIG. 10, the spiral lens 1302 allows for an elongation of the Z field of focus defined by an imaginary straight cylinder. Thus, the spiralization of different optical powers makes it possible to obtain a tubular focus of light rays. In other words, if in a prior art spherical lens 1301 one of the two diopter interfaces is replaced by a helical toric surface 1302 according to the present invention, this results in a longer focal area. The area of stigmatism no longer becomes a point, but a focal tube.

The inventor performed an optical ray tracing calculation for parallel illumination. In fig. 11 shows a lens 400 similar to the lens of FIG. 9, from the side of the focal point of the object. Focus area XV is shown enlarged at the top of FIG. 12.

In fig. 12 also shows the focal lengths D1 and D2 corresponding to the first curvature and second curvature of the original toric surface, respectively. On the right in Fig. 12, line 1501 shows the focal spot size in D1, and line 1502 shows the focal spot size in D2.

For comparison, at the bottom of FIG. 12 shows the same elements for an astigmatic lens, located axially opposite each other, as in FIG. 6, having the same curvature as the original ones from FIG. 11: Line 1511 shows the focal spot size on D1, and line 1512 shows the focal spot size on D2.

From fig. 12 clearly shows that the spiralization of the lens according to the invention causes the focal spot between D1 and D2 to be compressed into essentially the shape of an imaginary straight cylinder.

Other variations and advantages of the invention may be realized without departing from the scope of the invention.

If in the illustrated examples the helical segments were configured to extend directly through the optical surface of the lens, it may be possible to provide helicalization in only one area.

Thus, in FIG. 13 shows an embodiment in which the optical lens 300 includes a spherical surface 302 located at the center of the optical surface of the lens 300, with spiral segments provided only at the periphery of the optical surface.

In fig. 14 shows an embodiment in which an optical lens 100 with two concentric toric surfaces 102, 104 has a connecting part 114 made in a spiral according to the invention.

The invention is not limited to the examples just described; in particular, it is possible to combine features of the illustrated examples in embodiments that are not illustrated.

Claims (18)

1. An optical device (100, 200, 400, 800) having an optical axis containing at least one surface with at least two meridians, at least one part of which forms, when viewed from the front, at least one helical segment, the central point (206, 406, 806) of which is on the optical axis, with each spiral segment defining meridians with different optical powers so that the resulting focus is distributed over the tubular region. 2. An optical device according to claim 1, wherein one or more spiral segments are formed from a toric surface having a first meridian curved with a first non-zero curvature, and a second meridian (202 ₂ , 803) curved with a second curvature that is strictly greater than the first curvature, with the second meridian perpendicular to the first meridian. 3. The optical device of claim 2, wherein the one or more helical segments are formed from first and second toric surfaces, wherein the first toric surface (208 ₂ , 401) has a first meridian (202 ₁ , 401 ₁ ) curved with a first non-zero curvature around the axis of rotation of the first torus, and the second meridian (202 ₂ ), curved with a second curvature that is strictly greater than the first curvature, and the second meridian is perpendicular to the first meridian, and the second toric surface (208 ₁ , 402) has a first meridian (204 ₁ , 402 ₁ ), curved with the first non-zero curvature around the axis of rotation of the second torus, and the second meridian (204 ₂ ), curved with the second curvature, which is strictly greater than the first curvature, and perpendicular to the first meridian (204 ₁ ) of the second toric surface, wherein the first and second toric surfaces each contain a plurality of azimuthal angular sectors located around the optical axis, the first meridian (202 ₁ , 401 ₁ ) of the first toric surface (208 ₂ , 401) and the first meridian (204 ₁ , 402 ₁ ) of the second toric surface (208 ₁ , 402) have azimuthal orientations separated by a non-zero angle relative to the optical axis, the spiral segments define the first and second meridians (202 ₁ , 401 ₁ ; 204 ₁ , 402 ₁ ) of optical power, obtained from the first meridian (208 ₂ , 401) of the first toric surface and from the first meridian (208 ₁ , 402) of the second toric surface. 4. The optical device (200, 400) according to claim 3, wherein the azimuthal angular sector (208 ₂ ) of the first toric surface and the azimuthal angular sector of the second toric surface (208 ₁ ) are adjacent through the helical segment boundary (210). 5. The optical device (200) according to claim 3 or 4, wherein the first toric surface (208 ₂ , 208 ₄ ) and the second toric surface (208 ₁ , 208 ₃ ) each contain two diametrically opposed azimuthal angular sectors. 6. The optical device (200) of claim 5, wherein each corner sector of the first toric surface (208 ₂ , 208 ₄ ) is adjacent to two corner sectors of the second toric surface (208 ₁ , 208 ₃ ). 7. Optical device (200, 400) according to any one of claims 3-6, in which the angle between the azimuthal orientations of the first meridian of the first toric surface (208 ₂ , 401) and the first meridian of the second toric surface (208 ₁ , 402) is from 60 ° up to 90°. 8. An optical device (200, 400) according to any one of claims 3 to 7, wherein the first curvature of the first toric surface (208 ₂ , 401) is equal to the first curvature of the second toric surface (208 ₁ , 402). 9. An optical device according to any one of claims 3 to 8, wherein the second curvature of the first toric surface (208 ₂ , 401) is equal to the second curvature of the second toric surface (208 ₁ , 402). 10. An optical device (200, 400, 800) according to any of the previous paragraphs, in which the radius of the helical segment is related in polar coordinates to the angle of the helix according to a linear law, a quadratic law, or a logarithmic law. 11. An optical device according to any of the previous claims, further comprising a spherical surface (302) centered on the optical axis. 12. An optical device (200, 400, 800) according to any of the previous paragraphs, forming an optical lens whose front side is a surface with at least one helical segment. 13. Use of an optical device (200, 400, 800) according to any of the previous paragraphs for vision correction. 14. Use of an optical device (200, 400, 800) according to any one of claims 1 to 12 for concentrating light power. 15. Use of an optical device (200, 400, 800) according to any one of claims 1 to 12 for image formation.