JP2009069462A - Eyeglass lens, and method of manufacturing eyeglass lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an eyeglass lens capable of reducing astigmatism generated intensively on intermediate side parts arranged on both sides of a progressive part. <P>SOLUTION: The eyeglass lens includes a distant part 1A, a near part 1B, and the progressive part 1C of which refractive power changes progressively between the distant part 1A and the near part 1B, and the intermediate side parts 1D provided on both sides of the progressive part 1C. The intermediate side part 1D has a diffraction structure 4, and a longitudinal axis y and a horizontal axis x of the diffraction structure 4 has different pitches. That is, the diffraction structure 4, in which a normal line passes through a fitting point FT, is formed of a plurality of straight lines arranged in parallel to each other. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a spectacle lens having a distance portion, a near portion, a progressive portion in which refractive power gradually changes between the distance portion and the near portion, and a method of manufacturing the spectacle lens. .

  In recent years, when the ability to adjust the eye has decreased due to presbyopia or the like, a bifocal spectacle lens has been used. This spectacle lens is a progressive multifocal spectacle lens in which one lens has different powers. In this progressive multifocal spectacle lens, for example, the upper part is a distance part for viewing the distance, the lower part is a near part for viewing the distance, and the refractive power is progressively increased from the distance part to the near part. It is a progressive portion that changes, and a progressive surface constituting the distance portion, the near portion, and the progressive portion is added to the eyeball side surface or the object side surface.

Since such a progressive multifocal spectacle lens is designed to reduce astigmatism on the main line of sight, it is located on the side of the intermediate portion provided on both sides of the progressive portion (the ear side and the nose side of the progressive zone). Astigmatism is concentrated.
FIG. 13 shows a state in which astigmatism is concentrated on the side of the intermediate portion.
FIG. 13A is an aberration diagram of a progressive multifocal spectacle lens, and FIG. 13B is a frequency distribution diagram thereof. The progressive multifocal spectacle lens shown in FIGS. 13A and 13B has a base curve of 4.00 D, an addition power of 2.00 D, a progressive length of 14 mm, The progressive start position (Fitting point) (x, y) is (0, 4) mm and the diameter (DIA) is 60 mm.

As shown in FIGS. 13A and 13B, the upper portion of the progressive multifocal lens is the distance portion A, and the lower portion is the near portion B. A progressive portion C is provided from the distance portion A to the near portion B, and intermediate side portions D are provided on both sides of the progressive portion C. The intermediate portion side D has a power of 4.5D and an aberration of 2.0D.
Astigmatism is concentrated on the side of the intermediate part (ear side and nose side of the progressive zone), and this causes blurring, distortion, and shaking of the image to the eyeglass user.

Here, as a conventional example for correcting the aberration, there is a spectacle lens having a diffractive structure (Patent Document 1).
This conventional spectacle lens has a diffractive structure composed of steps that are rotationally symmetric with respect to the optical axis.
This diffractive structure is composed of steps formed on concentric circles, and the pitch of the steps decreases as the distance from the center of the lens increases.

JP 2000-284238 A

However, in the progressive multifocal lens, there is no conventional example for correcting astigmatism. In the conventional example shown in Patent Document 1, the object to be corrected is chromatic aberration, not astigmatism.
That is, in the conventional example shown in Patent Document 1, all the diffractive structures are composed of concentric annular zones with respect to the optical axis, and there is a problem that it is not possible to cope with elimination of astigmatism on the side of the intermediate portion.

  An object of the present invention is to provide a spectacle lens and a method for manufacturing a spectacle lens that can reduce astigmatism that is concentrated on the side of an intermediate portion provided on both sides of a progressive portion.

Therefore, in the spectacle lens of the present invention, either the object-side surface or the eyeball-side surface is a distance portion, a near portion, and the refractive power is progressive between the distance portion and the near portion. A progressive lens having a progressive surface that changes gradually, and a progressive surface provided on both sides of the progressive portion, the intermediate portion being provided with a diffractive structure on the side of the intermediate portion. The pitch is different between the vertical axis and the horizontal axis crossing the vertical axis.
In the invention of this configuration, in order to correct astigmatism on the side of the intermediate portion, the diffractive structure is arranged so as to act on a region where astigmatism is concentrated. At this time, the astigmatism due to the diffraction structure and the astigmatism generated by the macroscopic surface shape of the progressive multifocal lens are offset.
Therefore, the astigmatism caused by the macroscopic surface shape on the side of the intermediate portion can be reduced by the amount of astigmatism provided by the diffraction structure.
As a result, astigmatism on the side of the intermediate portion is reduced, and blurring, distortion, and shaking of the image are less likely to be given to the eyeglass user.

Here, in the spectacle lens of the present invention, the diffractive structure may be composed of a plurality of straight lines arranged in parallel to each other, or the diffractive structure is concentrically centered on a predetermined position on the side of the intermediate portion. It is good also as what is comprised from the several ellipse formed in this.
If the diffractive structure is composed of a plurality of straight lines, the diffractive structure can be accurately aligned, so that the diffractive structure can be easily formed on the spectacle lens.
If the diffractive structure is composed of a plurality of ellipses, the frequency change between the vertical axis and the horizontal axis becomes smooth, so that eye wear is not caused to the user of the glasses.

The diffractive structure is preferably provided on the object side surface.
In the invention with this configuration, if a diffractive structure is provided on the object side surface, astigmatism can be corrected even if the progressive surface is processed on the side surface of the eyeball.

The diffractive structure preferably has a concave lens effect such that a light beam incident in parallel with the optical axis is separated from the optical axis.
In the invention of this configuration, since the concave lens effect is generated by the diffractive structure, a large astigmatism can be imparted.

The diffractive structure preferably has a plurality of chevron shapes with continuous cross sections, and the pitch of the chevron shape decreases as the distance from the optical axis increases, or the angle of the chevron shape increases with respect to a plane perpendicular to the optical axis.
In the invention with this configuration, it is possible to easily manufacture a spectacle lens that can correct astigmatism by simply forming a predetermined chevron shape on the spectacle lens.

The diffractive structure is preferably formed on a lens substrate, and a coating layer made of a material having a refractive index different from that of the lens substrate is formed on the diffractive structure formed on the lens substrate.
In the invention of this configuration, since the coating layer is formed on the diffractive structure, the diffractive structure is protected by the coating layer, and the durability of the spectacle lens can be ensured.

The spectacle lens manufacturing method of the present invention is a method for manufacturing a spectacle lens having the above-described configuration, wherein a transfer shape that is reversed to the diffraction structure is formed in a lens mold by lithography, and a lens substrate is formed using the lens mold. It is characterized by manufacturing.
In the invention of this configuration, a transfer shape is formed on the lens mold by a simple technique called lithography, and when the lens is manufactured with the lens mold, the transfer structure is transferred to the spectacle lens itself to easily form the diffraction structure. it can.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
First, the structure of the progressive multifocal spectacle lens 1 according to the present embodiment will be described with reference to FIGS.
FIG. 1 is a schematic view of the spectacle lens 1 as seen from the front. FIG. 2 is a cross-sectional view of the spectacle lens 1.

In FIG. 1, the spectacle lens 1 has an upper portion as a distance portion 1A and a lower portion as a near portion 1B. A progressive portion 1C is provided from the distance portion 1A to the near portion 1B, and intermediate side portions 1D are provided on both sides of the progressive portion 1C. The progressive portion 1C is formed from a fitting point FT formed on the vertical axis y to a predetermined negative position on the vertical axis y.
In FIG. 2, the spectacle lens 1 includes a plastic lens substrate 2 and a coating layer 3 provided on the object side surface of the plastic lens substrate 2.
The plastic lens substrate 2 has a diffractive structure 4 formed on the surface facing the coating layer 3, that is, the object side surface, and a progressive surface 5 formed on the eyeball side surface in the intermediate side 1D. The progressive surface 5 is provided with the above-mentioned distance portion 1A, near portion 1B, progressive portion 1C and intermediate portion side 1D. In FIG. 2, the left side is the object side, and the right side is the eyeball side.

  The plastic lens substrate 2 is formed of a thermosetting resin. This thermosetting resin is, for example, tetrakis (2,3-epithiopropylthio) tin, tetrakis (2,3-epithiopropylthio) silicon, tetrakis (2,3-epithiopropylthio) having a high refractive index. Examples thereof include thermosetting resins obtained by polymerizing compounds such as zirconium, tetrakis (2,3-epithiopropylthio) germanium, tetrakis (2,3-epithiopropylthio) titanium.

The coating layer 3 is allyl diglycol carbonate or other synthetic resin material and has a refractive index of n1, and this refractive index n1 is not the same as the refractive index n2 of the plastic lens substrate 2.
A primer layer, a hard coat layer, and an antireflection layer (not shown) are formed on the surface of the coating layer 3 as necessary. A known material can be used for these layers.

  In the spectacle lens 1 shown in FIG. 1, the planar view of the diffractive structure 4 is a plurality of linear gratings each having a normal line toward the fitting point FT and inclined by 45 ° with respect to the horizontal axis x. . These gratings are parallel to each other. In this embodiment, instead of the diffractive structure 4 shown in FIG. 1, the diffractive structure 4 shown in FIG. 3, that is, concentrically about the substantially central portion of the region 1D in the middle portion side view in plan view. A plurality of elliptical annular lattices may be used.

FIG. 4 shows a cross section of the spectacle lens 1. 4A is a cross-sectional view taken along the line AA of the spectacle lens 1 shown in FIG. 1, and FIG. 4B is along the line BB of the spectacle lens 1 shown in FIG. FIG.
As shown in FIG. 4A, in the spectacle lens 1 whose front is shown in FIG. 1, the diffractive structure 4 is formed by continuously forming a plurality of cross-sectional chevron shaped portions 4A from the fitting point FT to the peripheral portion. Shape.
As shown in FIG. 4B, in the spectacle lens 1 whose front is shown in FIG. 3, the diffractive structure 4 has a shape in which the cross-sectional chevron portions 4A are continuously formed. The diffractive structure 4 is symmetrical on the left and right.

The chevron shaped portion 4A constituting the diffractive structure 4 includes a rising surface 4A1 substantially parallel to the optical axis Z and an inclined surface 4A2 formed continuously with the rising surface 4A1.
In order to produce a concave lens effect in which the light beam incident on the diffractive structure 4 in parallel with the optical axis Z is separated from the optical axis Z, the inclined surface 4A2 has an intersection between the vertical line segment and the optical axis Z. It is formed so as to be closer to the object side than the lens 1.

In the present embodiment, the diffractive structure 4 is designed so as to reduce the astigmatism on the side part D occurring in the conventional progressive multifocal lens.
When the spherical power by the diffractive structure 4 is Φ _P and the spherical power by the macroscopic surface shape of the lens surface is Φ _L , the spherical power Φ of the entire lens surface can be obtained from the sum of both, Φ = Φ _P + Φ _L.
The diffractive structure 4 is specifically obtained from the following equation.
First, the height of the rising surface 4A1 of the chevron shaped portion 4A is the lattice thickness d, and this lattice thickness d is obtained from the following equation (1).

For example, in order to form the diffractive structure 4 of the spectacle lens 1 whose front is shown in FIG. 3, a mercury lamp e-line λ ₀ = 546.07 nm (JIS T7330) is used as the reference wavelength.
The material of the coating layer 3 is allyl diglycol carbonate (n ₁ = 1.50), and the plastic lens substrate 2 is a thiourethane resin (Mitsui Chemicals, Inc. MR-8, n ₂ = 1.60). The optical path length difference m given by the diffractive structure 4 is one wavelength (m = 1).
The specific lattice thickness d under the above conditions is d≈5.46 μm.
The material of the coating layer 3 is allyl diglycol carbonate (n ₁ = 1.50), and the plastic lens base 2 is a disulfide resin (Mitsui Chemicals, Inc. MR-174, n ₂ = 1.74). The optical path length difference given by the diffractive structure 4 is one wavelength (m = 1).
The specific lattice thickness d under the above conditions is d≈2.28 μm.

  The radius of the annular zone of the m-th diffractive structure 4 counted from the center point CP (pitch of the diffractive structure 4) is obtained from the following equation (2). In the formula, f is a focal length.

Here, in consideration of the refractive index n2 of the plastic lens substrate 2 constituting the diffractive structure 4, the radius rm of the _mth diffractive structure annular zone is as shown in Expression (3).

  Therefore, the pitch of the annular zone of the diffractive structure 4 is as shown in the equation (4).

For example, if the spherical power is 0.50 diopter (S doe = 0.50D) and the sum of the spherical power and the astigmatic power is 1.00 diopter (S + C doe = 1.00D), the pitch relationship is shown in FIG. Street.
In FIG. 5, reference symbol P ₁ is a grating inclined by 45 ° from the horizontal axis x, and reference symbol P ₂ is a grating inclined by 135 ° (45 ° + 90 °) from the horizontal axis x. Pitch P ₁ and the pitch P ₂ and is seen to be different from FIG. Moreover, these pitches P ₁ and P ₂ become smaller from the center point CP toward the peripheral edge (as the number increases). Therefore, if the lattice thickness d is constant, the angle formed by the inclined surface 4A2 with the center point CP increases as it goes toward the peripheral edge.
Here, the pitch in the vertical axis direction and the pitch in the horizontal axis direction are in the relationship of Expression (5) in each annular zone.

  When connecting the diffraction element on the vertical axis and the diffraction element on the horizontal axis with an ellipse, if the number of the ellipse (ring zone) is m (m = 0, 1, 2,...), The diffraction structure 4 can be expressed by the elliptic equation shown.

On the other hand, in order to form the diffraction structure 4 of the spectacle lens 1 whose front is shown in FIG. 1, as in the case of the spectacle lens 1 shown in FIG. 3, the mercury lamp e-line λ ₀ = 546.07 nm as the reference wavelength. (JIS T7330) is used. The material of the coating layer 3 and the material of the plastic lens substrate 2 are the same as those shown in FIG. 3, and the optical path length difference m given by the diffractive structure 4 is also one wavelength (m = 1) as shown in FIG. It is. Therefore, the specific grating thickness d of the progressive multifocal spectacle lens 1 of FIG. 1 is d≈5.46 μm.
For example, assuming that the spherical power is 0.00 diopter (S doe = 0.00D) and the sum of the spherical power and the astigmatic power is 0.50 diopter (S + C doe = 0.50D), the pitch relationship is shown in FIG. Street. In calculating the numerical values, the above formulas (1) to (6) are referred to.
In FIG. 6, reference numeral P ₁ is a grating inclined by 45 ° from the horizontal axis x, and reference numeral P ₂ is a grating inclined by 135 ° (45 ° + 90 °) from the horizontal axis x, but the spectacle lens shown in FIG. in 1, the diffractive structure 4 is formed from a plurality of straight lines, because these lines coincides with the line of 45 ° from the horizontal axis x, the pitch indicated by the reference numeral P ₂ is 0.

Next, a method for manufacturing the spectacle lens 1 having the above-described configuration will be described with reference to FIGS.
[Diffraction structure forming process to lens mold]
As will be described later, a thermosetting resin is injected into a mold 15 having a pair of lens molds 10 to polymerize the plastic lens substrate 2, but diffraction is performed on one lens mold 10 of the pair of lens molds 10. A transfer shape 40 that is opposite to the structure 4 is formed. Therefore, a photosensitive material is thinly and uniformly applied to the inner surface of the lens mold 10, and the pattern is baked with light and transferred.

[Molding process]
The molding process assembled using the lens mold 10 will be described with reference to FIG.
In FIG. 7, while rotating the pair of lens molds 10 held by the chucks 12 and 13, the tape 14 is wound around the peripheral portions of the pair of lens molds 10, and the tape 14 is wound around the entire peripheral surfaces of the pair of lens molds 10. When it is done, a predetermined position is cut with a cutter (not shown). Thereby, the mold 15 is shape | molded.
In FIG. 7, reference numeral 16 denotes a roll that presses the tape 14 against the peripheral surface of the lens mold 10.

[Plastic polymerization process]
The plastic polymerization process will be described with reference to FIG. FIG. 8 shows a plastic lens manufacturing apparatus.
In FIG. 8, the plastic lens manufacturing apparatus includes a resin injection mechanism 20 that injects a thermosetting resin into the mold 15, and the resin injection mechanism 20 supplies a resin raw material into the mold 15. 21 and a control unit 22 for controlling the amount of the resin raw material to be supplied.
The supply unit 21 is connected to a nozzle 211 for injecting a resin material into the mold 15, a resin material flow pipe 212 having a lower end connected to the base end of the nozzle 211, and an upper end of the resin material flow pipe 212. The amount of the resin raw material supplied from the nozzle 211 is controlled by controlling the opening amount with an injection control valve 214 provided in the resin raw material distribution pipe 212.
The control unit 22 includes a flow rate adjusting unit 221 that controls the injection control valve 214, a sensor 222 that detects that the resin raw material has been injected into the mold 15 to a predetermined position, a sensor 224 that switches the flow rate of the resin raw material, And a control unit main body 223 for receiving the signals from the sensors 222 and 224 and controlling the flow rate adjusting unit 221.

In the plastic lens manufacturing apparatus, a thermosetting resin is injected into the mold 15 by the resin injection mechanism 20. At this time, the liquid level of the thermosetting resin rises with the injection of the resin raw material, but the sensor 224 detects that the liquid level has reached the vicinity of the injection port 14A, and the injection flow rate is gradually reduced. . When the sensor 222 detects that the resin raw material is filled in the mold 15, a signal from the sensor 222 is sent to the control unit 22, and the injection of the resin raw material is stopped. After the resin injection, the injection port 14A is sealed by an appropriate means. When the inlet 14A is sealed, the mold 15 is placed in a furnace and cured by heating.
As a result, the plastic is polymerized and the transfer shape 40 formed on the lens mold 10 is transferred to the plastic lens substrate 2.

[Release process]
In the mold 15 taken out from the furnace, the tape 14 is peeled off from the peripheral surfaces of the pair of lens molds 10, and the pair of lens molds 10 is peeled off to form the plastic lens substrate 2. Since this plastic lens substrate 2 is a semi-finished lens, it becomes a spectacle lens 1 having a progressive surface by a process described later.
[Coating layer forming process]
A coating layer 3 is formed on the surface of the plastic lens substrate 2 on which the diffractive structure 4 is formed. For this purpose, a lens mold (not shown) is arranged facing the surface of the plastic lens substrate 2 on which the diffractive structure 4 is formed, and a synthetic resin for forming the coating layer 3 between the lens mold and the plastic lens substrate 2 is used. Inflow. After the synthetic resin is cured, the lens mold is removed.

[Eyeball side surface formation process]
A progressive surface is formed on one surface of the plastic lens substrate 2 manufactured by the above process.
Therefore, a spectacle lens blank in which the diffractive structure 4 and the coating layer 3 are provided in advance is prepared, and the opposite side of the surface on which the diffractive structure 4 of the plastic lens substrate 2 is provided, that is, on the side of the eyeball according to the prescription. Machining the progressive surface. This processing step is the same as the conventional one, and is performed, for example, by the method described in JP-A-10-175149.
Thereafter, a primer layer, a hard coat layer and an antireflection layer are formed on the surface of the spectacle lens 1 in the same manner as in the prior art.

Therefore, in the present embodiment, the following operational effects can be achieved.
(1) The spectacle lens 1 includes a distance portion 1A, a near portion 1B, a progressive portion 1C in which refractive power changes progressively between the distance portion 1A and the near portion 1B, and a progressive portion 1C. An intermediate portion side 1D provided on both sides is provided, and the intermediate portion side 1D is provided with a diffractive structure, and the vertical axis y and the horizontal axis x of the diffractive structure 4 have different pitches. In other words, in order to correct the astigmatism on the intermediate side 1D, the astigmatism caused by the diffractive structure 4 and the astigmatism generated by the macroscopic surface shape of the progressive multifocal lens are canceled out. The difference in curvature radius between the astigmatism axis direction at the intermediate side 1D and the cross axis direction orthogonal to the astigmatism axis is reduced by the amount of astigmatism imparted by the diffractive structure 4, thereby Astigmatism has been reduced, and image blurring, distortion, and shaking are less likely to be given to spectacle users.

(2) By configuring the diffractive structure 4 from a plurality of straight lines that pass through the fitting point FT and that are arranged in parallel to each other, the diffractive structure 4 can be accurately aligned. Can be easily formed on the eyeglass lens 1.
9 to 12 show graphs for confirming the effects when the diffractive structure 4 is composed of a plurality of straight lines arranged in parallel to each other.
In FIGS. 9 to 12, the line indicated by reference numeral Q ₀ is the spherical power of the lens surface, the line indicated by reference numeral Q ₁ is a frequency when the added aberrations of the lens surfaces, reference symbol S the cylinder axis Is the angle.

FIG. 9 shows the relationship between the power (pow (D)) and the position of the horizontal axis x at the position where the vertical axis y of the spectacle lens 1 of the present embodiment is −10 mm (y = −10 mm) and the astigmatic axis. The relationship between the orientation and the position of the horizontal axis x is shown. The position of −10 mm on the vertical axis y is a position near the end position of the progressive surface.
FIG. 10 shows a spectacle lens in a conventional example, and this spectacle lens has the same conditions as in FIG.
9 and 10, in the present embodiment and the conventional example, differ in degree plus aberration of the lens surface indicated by reference numeral Q _1. That is, in this embodiment, the power decreases in the region of +10 mm or more and −10 mm or less on the horizontal axis x as compared with the conventional example, and it can be seen that the astigmatism is reduced by the diffraction structure 4.

FIG. 11 shows the relationship between the power (pow (D)) and the position of the horizontal axis x at the position where the vertical axis y of the spectacle lens 1 of the present embodiment is 4 mm (y = 4 mm) and the direction of the astigmatic axis. The relationship with the position of the horizontal axis x is shown. A position of 4 mm on the vertical axis y is a fitting point where the progressive surface starts.
FIG. 12 shows a spectacle lens in a conventional example, and this spectacle lens has the same conditions as in FIG.
11 and 12, in the present embodiment and the conventional example, differ in degree plus aberration of the lens surface indicated by reference numeral Q _1. That is, in this embodiment, the power decreases in the region of +8 mm or more and −8 mm or less on the horizontal axis x as compared with the conventional example, and it can be seen that the astigmatism is reduced by the diffraction structure 4.

(3) If the diffractive structure 4 is composed of a plurality of ellipses, the frequency change between the vertical axis y and the horizontal axis x becomes smooth. Therefore, even if a user wearing glasses changes his / her line of sight, the eyes will not become tired.
(4) Since the diffractive structure 4 is provided on the object side surface, astigmatism can be imparted even if the eyeball side surface is processed.

(5) Since the diffractive structure 4 is configured to produce a concave lens effect in which a light beam incident in parallel to the optical axis Z is separated from the optical axis, large astigmatism can be efficiently imparted.
(6) The diffractive structure 4 has a plurality of chevron-shaped portions 4A having a continuous cross section, and the pitch between the chevron-shaped portions 4A decreases from the optical axis Z toward the peripheral portion. It is possible to easily manufacture the spectacle lens 1 capable of producing the above-described effect simply by forming the spectacle lens.

(7) Since the diffractive structure 4 is formed on the plastic lens substrate 2 and the coating layer 3 having a refractive index different from that of the plastic lens substrate 2 is formed on the diffractive structure 4 of the plastic lens substrate 2, the plastic lens The diffractive structure 4 formed on the substrate 2 is protected by the coating layer 3, and the durability of the spectacle lens 1 can be ensured.

(8) The transfer shape 40 is formed on the lens mold 10 by a simple technique called lithography, and the transfer shape 40 is transferred when the plastic lens substrate 2 is polymerized using the lens mold 10 to form the diffraction structure 4. did. Therefore, the diffractive structure 4 can be easily formed on the plastic lens substrate 2.

(9) Since the spectacle lens blank having the diffraction structure 4 provided in advance on the object side surface is prepared and the progressive surface is processed in accordance with the prescription, the parts of the spectacle lens 1 can be shared. .

It should be noted that the present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.
For example, in the above-described embodiment, the diffractive structure 4 is configured by a plurality of ellipses or a plurality of straight lines formed concentrically. However, in the present invention, the diffraction structure 4 is formed by a plurality of triangles formed concentrically or concentrically. A plurality of rectangles may be diffractive structures.
In the present invention, it is not always necessary to provide the coating layer 3.
Further, the substrate may be formed from glass other than plastic, for example.
The method of forming the diffractive structure 4 on the plastic lens substrate 2 is not limited to the method of forming the transfer shape 40 on the lens mold 10 by lithography. For example, the diffractive structure is formed on the lens substrate using a laser. 4 may be formed directly.

  The present invention can be used for spectacle lenses formed of plastic or other materials.

The schematic diagram which looked at the spectacle lens concerning one Embodiment of this invention from the front. Sectional drawing of the said spectacle lens. The schematic diagram which looked at the spectacle lens of the diffraction structure different from FIG. 1 from the front. (A) is an arrow sectional view along the AA line of FIG. 1, (B) is an arrow sectional view along the BB line of FIG. The graph which shows the relationship between the number of a grating | lattice, and a pitch in the spectacle lens shown in FIG. The graph which shows the relationship between the grating | lattice number and pitch in the spectacle lens shown in FIG. The perspective view explaining the outline of a mold formation process. The figure explaining the outline of a plastic polymerization process. The graph by which the relationship between the frequency (D) in the position where the vertical axis y of the spectacle lens of this embodiment is -10 mm, and the position of the horizontal axis x, and the direction of the astigmatic axis and the position of the horizontal axis x is shown. The graph which shows the relationship between the frequency (D) in the position whose vertical axis | shaft y of the prior art example is -10 mm, and the position of the horizontal axis x, and the relationship between the direction of an astigmatism axis, and the position of the horizontal axis x. The graph which shows the relationship between the frequency (D) in the position where the vertical axis | shaft y of the spectacle lens of this embodiment is 4 mm, and the position of the horizontal axis x, and the relationship between the direction of an astigmatism axis, and the position of the horizontal axis x. The graph which shows the relationship between the frequency (D) in the position where the vertical axis | shaft y of the prior art example is 4 mm, and the position of the horizontal axis x, and the relationship between the direction of the astigmatic axis and the position of the horizontal axis x. (A) is an aberration diagram of a conventional progressive multifocal spectacle lens, (B) is its frequency distribution diagram.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Eyeglass lens, 1A ... Distance part, 1B ... Near part, 1C ... Progressive part, 1D ... Intermediate part side, 2 ... Plastic lens base material, 3 ... Coating layer, 4 ... Diffraction structure, 4A ... Angle shape Part, 5 ... progressive surface, 40 ... transfer shape, 10 ... lens type, FT ... fitting point, x ... horizontal axis, y ... vertical axis

Claims (9)

Either the object-side surface or the eyeball-side surface is a distance portion, a near portion, a progressive portion whose refractive power changes progressively between these distance portions and the near portion, and progressive A spectacle lens having a progressive surface with intermediate side portions provided on both sides of the portion,
A spectacle lens characterized in that a diffraction structure is provided on a side of the intermediate portion, and a pitch of the diffraction structure is different between a vertical axis and a horizontal axis intersecting the vertical axis. The spectacle lens according to claim 1,
The eyeglass lens, wherein the diffractive structure is composed of a plurality of straight lines arranged in parallel to each other. The spectacle lens according to claim 1,
The diffractive structure is composed of a plurality of ellipses formed concentrically around a predetermined position on the side of the intermediate portion. In the spectacle lens according to any one of claims 1 to 3,
The spectacle lens, wherein the diffractive structure is provided on an object side surface. The spectacle lens according to claim 4,
An eyeglass lens, wherein the progressive surface is processed on a side surface of the eyeball. In the spectacle lens according to any one of claims 1 to 5,
The spectacle lens according to claim 1, wherein the diffractive structure produces a concave lens effect such that a light beam incident parallel to the optical axis is separated from the optical axis. In the spectacle lens according to claim 6,
The diffractive structure has a plurality of chevron shapes with continuous cross sections, and the pitch of the chevron shape decreases as the distance from the optical axis increases, or the inclination of the chevron shape increases with respect to a plane perpendicular to the optical axis. Eyeglass lens. In the spectacle lens according to any one of claims 1 to 7,
The diffractive structure is formed on a lens base material, and a coating layer made of a material having a refractive index different from that of the lens base material is formed on the diffractive structure formed on the lens base material. . A method of manufacturing a spectacle lens according to any one of claims 1 to 8,
A method for manufacturing a spectacle lens, comprising: forming a transfer shape that reverses the diffraction structure in a lens mold by lithography; and manufacturing a lens substrate using the lens mold.

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