JP2008089618A - Glasses lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a glasses lens which can be used not only as a vision correcting tool but positively as tension easing auxiliary tool at near vision. <P>SOLUTION: The glasses lens (1) is for normal vision or vision correction, with a tension easing area, for reducing a regulating power at near vision to ease the tensed condition of an eye, being formed in a near vision area used for near viewing. The tension easing area is formed well below a distant vision area used for distance viewing via a 8-18 mm power transition area (19). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a spectacle lens, and more particularly to relaxation of eye tension in spectacle lenses for normal vision or vision correction.

  The progressive focus lens developed in 1972 has since undergone many design improvements, and has increased its demand as a spectacle lens for the senior generation that compensates for adjusting power according to applications such as far, middle, near and near. Yes. Although it is known that the decline of accommodation is progressing from a fairly young age, it is generally used for correcting vision such as normal myopia, hyperopia, and astigmatism for younger age than the presbyopia generation that starts around 40 years old. The current situation is that only the function of the lens is sufficient.

  However, reflecting the recent IT era, there are many opportunities to increase the stress applied to the eye accommodation function, and as a negative effect, there are more cases of symptoms such as shoulder stiffness and neck stiffness besides eye fatigue. This phenomenon is a problem that may occur even for a normal sighter who does not require correction of visual acuity (originally does not require a spectacle lens), and an examinee or a PC user who keeps eye tension for a long time is no exception. As a result, in addition to these subjective symptoms, actual harm such as false myopia occurs.

  The present invention has been made in view of the above-described problems, and provides a spectacle lens that can be actively used not only as a vision correction tool but also as a strain relief aid in near vision. Objective.

  In order to solve the above-mentioned problems, the present invention is a spectacle lens for normal vision or vision correction, and in a near vision region corresponding to a near view, the accommodation power of the eye is reduced by reducing the adjustment power at the near vision. There is provided a spectacle lens characterized in that a strain relief region for relaxing a tension state is formed.

  According to a preferred aspect of the present invention, the strain relief region is formed through a frequency transition region of 8 mm to 18 mm downward from a far vision region corresponding to a distant view. Moreover, it is preferable that the frequency of the strain relief region is set on the plus power side with respect to the far power by a predetermined power within a range of 0.5 diopter to 1.25 diopter. In this case, it is preferable that the predetermined frequency is set without depending on the magnitude of the far power. Moreover, it is preferable that the tension alleviating region is formed on at least one of the front surface and the rear surface of the semifinished blank material for a single focus lens. In the far vision region above the horizontal line passing through the distance eye point and having a radius of 30 mm or less around the distance eye point, astigmatism based on performance evaluation assuming wearing state is within 0.50 diopter. Preferably there is.

  In the spectacle lens of the present invention, a tension relief (stress relief) region is formed in the near vision region corresponding to the near view, and the adjustment power for near vision is reduced by the action of the strain relief region, and as a result Relieve tension. As a result, the spectacle lens of the present invention can be actively used not only as a vision correction tool but also as a strain relief assisting tool in near vision.

  Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a diagram schematically showing a configuration of a spectacle lens according to a first embodiment of the present invention. In the first embodiment, the present invention is applied to a normal single-focus spectacle lens. As shown in FIG. 1, the spectacle lens 1 of the first embodiment has a lens front surface 1a formed in a spherical shape or an aspherical shape with an optical center O as an axis of symmetry, and a strain relief region as described later. Lens rear surface 1b.

  Generally, in the case of a single focus lens, a distance eye point (also referred to as a fitting point) 11 indicated by a cross mark in the figure coincides with the optical center O, and a horizontal line (broken line in the figure) passes through the distance eye point 11. The region above 12 is a far vision region corresponding to a distant view (a distant line of sight passes). A circle 13 (shown by a broken line in the figure) adjacent to the distance eyepoint 11 in the far vision region is a measurement reference circle for the distance power (far power).

  On the other hand, a pair of small circles 14 and 15 that are horizontally spaced directly below the horizontal line 12 with the distance eye point 11 in between are horizontal reference marks (permanent marks). A circle 16 spaced downward from the distance eye point 11 is a measurement reference circle for the power of the near vision area corresponding to the near view (where the near line of sight passes), that is, the near vision power (near power). It is.

  A power transition region (intermediate progressive zone) exists between the far vision region above the horizontal line 12 and the near vision region centered on the measurement reference circle 16 for the near power. Curves 17 and 18 drawn by broken lines are examples of the present invention showing contour lines with astigmatism (astigmatic difference) of 0.5 diopters, that is, 0.5D as power curves.

  In the first embodiment, for example, using a semi-finished blank material for a single focus lens, the power in the measurement reference circle 16 of the near power, that is, the near power is the power in the measurement reference circle 13 of the distance power, that is, the far power. The rear surface 1b of the spectacle lens 1 is processed so as to have a power on the plus side of the far power by a predetermined power in the range of 0.5 diopter to 1.25 diopter, for example, irrespective of the size of the lens.

  As described above, in the spectacle lens 1 according to the first embodiment, for example, a strain relief region having a frequency on the plus side of the distance power by a power of about 0.5 diopter to 1.25 diopter is formed in the near vision region. Therefore, by the action of the strain relief region, it is possible to reduce the adjustment force necessary for near vision and to relax the eye tension state. That is, the spectacle lens 1 according to the first embodiment can be actively used not only as a visual acuity correction tool but also as a strain relief aid for near vision.

  In the above description, for example, the rear surface of the semifinished blank material for a single focus lens is processed. In the case of astigmatism prescription, the progressive surface for the strain relief region and the astigmatism surface may be fused on the rear surface, however, a progressive surface for the strain relief region is provided in front of the spectacle lens for normal vision or vision correction. In addition, an astigmatism surface may be provided on the rear surface. Alternatively, the strain relief region can be formed in the near vision region by processing both the front surface and the rear surface of the spectacle lens for normal vision or vision correction. The semi-finished blank material for a single focus lens is a semi-finished blank material conventionally used for a single focus lens.

  FIG. 2 is a diagram schematically showing a configuration of a spectacle lens according to a second embodiment of the present invention. The second embodiment is similar to the first embodiment, but is different from the first embodiment in that the present invention is applied to a polarizing spectacle lens. Therefore, in FIG. 2, the same reference numerals as those in FIG. 1 are assigned to the same elements as those in FIG. Hereinafter, the second embodiment will be described by paying attention to differences from the first embodiment.

  In the polarizing spectacle lens 2 of the second embodiment, since the polarizing filter 21 is embedded in the vicinity of the lens front surface 2a or bonded to the front surface 2a, the front surface 2a is processed and the strain relief region is formed in the near vision region. It is impossible to provide a progressive surface for Therefore, the front surface 2a is formed into a spherical shape or an aspherical shape with the optical center O as an axis of symmetry, and only the rear surface 2a of the lens is processed to provide a progressive surface for the strain relief region in the near vision region (near view). A strain relief function is added to the viewing area).

  In the example of FIGS. 1 and 2, the distance eye point and the center of the distance power measurement reference circle are drawn at positions separated from each other. However, it goes without saying that this can be matched depending on the lens design policy. Nor. In that case, it matches on a straight line connecting two horizontal reference marks. In this way, it is expected that the eyeglass lens of the present invention can be handled in the same manner as a single focus lens by aligning the center of the distance eye point and the distance power measurement reference circle on the horizontal reference line. it can.

  In the spectacle lens of the present invention, the distance from the distance eye point (in the case of a single focus lens, generally coincides with the optical center of the lens) to the position where the predetermined additional refractive power is obtained, that is, the frequency transition region 19 (FIGS. 1 and 2) (corresponding to the length of the progressive zone of the progressive power lens) is 8 mm to 18 mm (more preferably 8 mm to 15 mm), and as much lens aberration as possible remains in the far vision region of the upper half of the lens. No design is desirable. In other words, it is desirable that the strain relief region is formed downward from the far vision region via the power transition region 19 of 8 mm to 18 mm (more preferably, via the power transition region of 8 mm to 15 mm).

  In general, when the distance corresponding to the length of the progressive zone is shortened, the width of the progressive zone that can be clearly seen becomes narrower, and the astigmatism (astigmatism) generated in the side portion of the progressive zone increases rapidly. Not recommended in terms of aberration reduction. However, in the spectacle lens of the present invention, the added power is kept small and the power gradient is gentle. Therefore, in terms of usability of the line of sight, the length of the power transition region may be a small value within the range of the distance. In addition, in recent small spectacle frames, that is, spectacle frames with a narrow top and bottom width, it is desirable that the frequency transition region is short considering that it is cut by frame processing, but if the frequency transition region is too short, the frequency changes And the occurrence of astigmatism increases, the length of the power transition region is determined in consideration of the lens performance.

  In order to select a lens that matches the purpose of use of the wearer, a single-focus lens with the most variety of products on the market is optimal. In addition to various lens materials ranging from high refractive index to low refractive index, various anti-reflective coatings, water / oil repellency, dyeing, bonding of polarized light and special color filters, etc., in addition to various surface treatments, spherical design The design of the front surface of the lens, such as an aspherical design, can be selected as a product type. Since the product price of the lens reflects these functions, it is possible to select from an inexpensive one to an expensive one. It is advantageous to add a strain relief function to the rear surface of the semi-finished blank material of a single-focus lens product with many types so that the lens can be selected according to the purpose, preference, budget and the like.

  The spectacle lens of the present invention having a tension relieving function, for example, can slightly reduce the adjustment power necessary for near vision by the plus refractive power added to the near vision region of the single focus lens, and thus the eye It is intended to reduce fatigue. In particular, it is a useful lens for those in their 40s who can be regarded as a reserve arm of presbyopic glasses that are close to presbyopia. The spectacle lens of the present invention is similar in form to a progressive power lens (progressive focus lens) for presbyopia, but differs in the following points.

  First, in the spectacle lens of the present invention, unlike the progressive addition lens, since there is no idea that various types of addition power are prepared according to the adjustment power of the wearer, the added refractive power is, for example, 0.5 diopter to 1 A constant value within the range of 25 diopters. In addition, the wearing target of the spectacle lens of the present invention is an age group from a young group in their 20s to a late 40s of early presbyopia symptoms, That are not subject to. Furthermore, in the spectacle lens of the present invention, in particular, for the purpose of responding to various needs of users by adding a strain relief function to the rear surface of the semi-finished blank material for single focus lenses possessing many varieties. Yes. Further, as described above, it is possible to cope with various lenses in which a filter is attached to the front surface of the lens like a polarizing lens. For astigmatism prescription, it is possible to fuse the progressive surface for the strain relief region and the toroidal surface on the rear surface of the lens, but it is also acceptable to add a strain relief function to the front if there are restrictions on the processing of the rear surface Is done.

  Since the spectacle lens of the present invention having a tension relieving function is targeted for the generation where the adjustment power remains to some extent, the existence of the progressive zone is not important, so that the appearance is not seen in the presbyopia lens. Is important. In order to add a positive power without borders to the near vision region, it is necessary to form a progressive zone, but when a progressive zone is formed, as known as Minkitz's law, the side of the progressive zone is astigmatized. Aberration occurs. Since this astigmatism reduces visual acuity and causes image shaking and distortion, it is required to reduce it as much as possible, and progressive power lenses of various designs have been developed.

  In the spectacle lens of the present invention, it is particularly important to make the astigmatism in the far vision region (distance region) in the upper half of the lens as inconspicuous as possible. This is because it is natural that the visual acuity value is improved by wearing a single-focus lens according to the prescription, and lenses whose visual acuity is reduced by wearing the lens are generally not allowed. Therefore, it is important that the visual acuity of distant vision is not lost as much as possible, and is worn in a far vision region above the horizontal line passing through the distance eye point and having a radius of 30 mm or less around the distance eye point. It is desirable that the astigmatism by the performance evaluation assuming the above is suppressed within 0.50 diopter (more preferably within 0.25 diopter).

  Therefore, when designing a strain relief region using a semi-finished blank for single focus lenses according to the prescription power ordered, an optimization design should be adopted so that the lens performance is optimized at that prescription power. Can also be selected. Although the manufacturing method with a base curve is reasonable, as described later, the best performance is not always ensured at all frequencies in the production frequency range. Optimizing the lens surface design when setting is effective and useful.

  In addition to the prescription power described above, this optimization can target various parameters such as the shape of the spectacle frame, the wearing distance of the lens, the near vision distance, the forward tilt angle of the lens, and the tilt angle of the lens. Above all, considering the shape of the spectacle frame of the wearer and optimizing only this inner region will result in fewer design constraints than optimizing with the lens reference outer diameter, so aberration can be further reduced. The possibility remains and further improvement in performance can be expected.

  In addition, it is comfortable for the user to reduce the transmittance so that only an appropriate amount of light is transmitted through only the light rays that are kind to the eyes by selectively transmitting the light rays in consideration of the spectroscopic characteristics of the spectacle lens depending on the purpose of use. Can expect further tension relief effect. As an example, light having a shorter wavelength than 400 nm, which is a highly stimulating ultraviolet and blue light, is reduced or cut, and further, the transmittance is reduced only by a light having a wavelength range of 530 nm to 590 nm, which has the highest eye visibility. In addition, by having an anti-glare effect, it is possible to relieve the stimulus received by the retina of the eye and relieve eye strain. In addition, since the lens material formed by chelating with rare earth elements such as neodymium has an anti-glare effect, the transmittance is reduced by 15% or more in a spectral width between 530 nm and 590 nm with a half width of 15 nm or more. It is desirable to use a lens material. In addition, a tension-relaxing effect can also be expected in purple-type lens coloring that gives comfort.

  It is desirable to attach a permanent mark, a temporary paint mark, or the like on the front surface or the rear surface of the spectacle lens of the present invention. As shown in FIGS. 1 and 2, a horizontal reference mark as a permanent mark for lens alignment can be attached to the front or rear surface of the lens at a position of about 17 mm horizontally from side to side across the design center of the lens. Further, a pre-set strain relief function mark and a horizontal alignment mark may be processed as permanent marks on the front or rear surface of the lens so that it can be seen at a glance that the eyeglass lens has a strain relief function. Further, in order to indicate the horizontal reference mark position, generally, temporary paint marks can be attached at two locations along the horizontal direction on the same side as the alignment permanent mark.

  By the way, in the case of a progressive power lens, a semi-finished blank material consisting of several (3-5) base curves is generally prepared and the rear surface is processed, so a semi-finished blank material with the same base curve is used. The frequency range to be widened. In this case, in general, the lens is designed so that the power at the center of the power range is the best in terms of performance, and therefore the aberration of the lens tends to increase as the distance from the design power increases. From this point of view, single-focus lenses have more base curves than multifocal lenses or progressive-power lenses, so the frequency range that a semi-finished blank with one base curve can handle is narrowed. Therefore, it is possible to supply a product excellent in performance over a wide frequency range by adding a tension relaxation function to the rear surface of the semi-finished blank material for a single focus lens.

It is a figure which shows schematically the structure of the spectacle lens concerning 1st Embodiment of this invention. It is a figure which shows schematically the structure of the spectacle lens concerning 2nd Embodiment of this invention.

Explanation of symbols

1, 2 Eyeglass lenses 1a, 2a Front surfaces 1b, 2b of eyeglass lenses Rear eyepiece 11 Distance eye point 13 Distance power measurement reference circles 14, 15 Horizontal reference mark 16 Near power measurement reference circles 17, 18 0.5D As power curve 19 Power transition region 21 Polarizing filter

Claims (6)

A spectacle lens for normal vision or vision correction,
A spectacle lens characterized in that a near-field region corresponding to a near view is formed with a strain relief region for relieving a tension state of an eye by reducing an adjustment force when performing near vision. The spectacle lens according to claim 1, wherein the strain relief region is formed through a power transition region of 8 mm to 18 mm downward from a far vision region corresponding to a distant view. 3. The spectacles according to claim 1 or 2, wherein the power of the strain relief region is set to a plus power side with respect to a far power by a predetermined power within a range of 0.5 diopter to 1.25 diopter. lens. The spectacle lens according to claim 3, wherein the predetermined power is set without depending on the magnitude of the far power. The said tension relaxation area | region is formed in at least one surface of the front surface and the back surface of the semifinished blank material for single focus lenses, The any one of Claims 1 thru | or 4 characterized by the above-mentioned. Eyeglass lens. In the far vision region above the horizontal line passing through the distance eye point and having a radius within 30 mm with the distance eye point as the center, the astigmatism based on performance evaluation assuming wearing state should be within 0.50 diopter. The spectacle lens according to any one of claims 1 to 5.

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