CN1219680A - Eyeglass lens with gradually progressive focal length - Google Patents

Abstract

A progressive multi-focal-distance lens for glasses technically features that based on that the prism power at the geometric center (main reference point) of ordinary progressive multi-focal-distance lens for glasses is equal to zero, the geometric center moves down a proper distance to make the prism power at the geometric center not equal to zero. Its advantages are relaxing the fatigue of eyes, correcting the posture for reading and writing, and preventing myopia or delaying its deepaning.

Description

A kind of eyeglass lens with gradually progressive focal length

The present invention relates to a kind of lens, the eyeglass lens with gradually progressive focal length that especially a kind of teenager of being applicable to wears.

Eyeglass lens with gradually progressive focal length is a high-tech product now.After France in 1958 developed first eyeglass lens with gradually progressive focal length, nearly four during the last ten years, and the many developed countries in the world work out the eyeglass lens with gradually progressive focal length that has their own characteristics each in succession.In China,, the research of the eyeglass lens with gradually progressive focal length that is applicable to that teenager (10-16) wears in year and the preparation business of glasses have at first been released at home by the applicant since middle nineteen nineties.The main difference point of eyeglass lens with gradually progressive focal length and traditional common single focus lens is that this lens is made up of four zones, as shown in Figure 1: 1. far away from regional; 2. near with the zone; 3. fuzzy region; 4. progressive zone.Wherein far with the zone be used for that correction of refractive errors causes see that distant vision is not good.Near is that refractive diopter is far used in change along with additional number of degrees ADD (ADD=is far with the number of degrees-closely the use number of degrees) is big or small with the zone.Progressive zone is used to connect usefulness far away, closely uses two zones, thereby makes sight line arrive gradually from seeing the far field that vision is successional when seeing the near region.Present eyeglass lens with gradually progressive focal length in the world is used for the elderly more and wears, according to traditional design and processing request, the main reference point B of this kind lens is the lens geometric center, as shown in Figure 2, the C point is assembling "+" word line intersection point, and the C point is by wearer's interpupillary distance Pd and the high PH decision of pupil.At this moment, the prism degree at lens B point place is zero.B point top be an end prism up, is end prism down below the B point, as shown in Figure 3.Because the teenager is in growth and development stage, behind its lens the summit to eyes cornea distance usually less than adult distance (12mm), as shown in Figure 4.Therefore, when the teenager uses this kind lens, certainly will cause lens than the close more eyes of adult.Just because of this kind is close, make teenager wearer see when near, can not fully fully use near as the adult with the zone, as shown in Figure 5.To this defective, the asymptotic multi-focal spectacle lens of tradition processing can only adopt the method for upwards raising lens in strong timing artificially, as shown in Figure 6.Fully use nearly problem with the zone though the method can solve, can find in conjunction with Fig. 3, the wearer also can make when far away below the B point of sight line in Fig. 2 by the end prism arrival object of seeing down seeing.And end prism down is according to optical principle, the beholder seen on the image of an object move, as shown in Figure 7.When the people watches the image of moving for a long time, owing to eyes must look up, thereby the fatigue of eyes very easily takes place, especially for the teenager, more can influence the normal development of eyeball.

The object of the present invention is to provide a kind of overcome above-mentioned defective novel to be particularly useful for the eyeglass lens with gradually progressive focal length that the teenager wears.

Technical scheme of the present invention is: on the basis of adopting the eyeglass lens with gradually progressive focal length principle, during preparation main reference point (geometric center) B point among Fig. 2 moved down one suitably apart from d (0＜d＜3mm), thus produce a new main reference point (prism degree is zero) B ' point herein.Simultaneously, assembling "+" the word line intersection point C among Fig. 2 will shift to the B point, as shown in Figure 8.This moment, the prism degree at B point place no longer was zero, but had formed an end prism up that certain prism degree is arranged.Its prism degree is by formula p=d.F decision, and p represents the prism degree of this prism in the formula, and d represents the distance (cm of unit) between the BB ', and F represents wearer's near-sighted diopter.In order to obtain this prism degree, when preparation, will select base and top margin thickness that the lens of a certain amount of difference is arranged, and make this thickness difference g satisfy following formula: $g=\frac{\mathrm{Pd}}{100(n-1)}$ P represents prism degree in the formula, and d represents lens diameter (mm of unit), and n represents the refractive index of lens, the aerial velocity of propagation of 1 expression light, 100 expression computational constant.Because the prism degree that the present invention has made B order when lens is made in advance is non-vanishing, but be pre-formed at the bottom of one up prism, when then wearing to the teenager, the wearer sees when far away, sight line BB ' section be by one at the bottom of up prism, and end prism up can make the beholder see that the image of an object moves down according to optical principle, as shown in Figure 9, thereby the sight line that makes the people meets the physiological characteristic of eyeball, is difficult for making eye fatigue.This point is particularly important to the teenager.Meanwhile, be more suitable for wearing, correct its wrong read-write posture, prevent or delay its near-sighted intensification degree to reach in the teenager in order to make the present invention.In the manufacturing process of product of the present invention, determine according to the difference of additional number of degrees ADD, the channel width L in progressive zone, as shown in the table:

Additional number of degrees ADD	The clear ken (channel width L)
		????+1.00D ????+1.50D ????+2.00D ????+2.50D	????7.5-8.5mm ????5.0-6.0mm ????3.0-4.0mm ????2.0-3.0mm

Therefore, the present invention be adopt add in advance an end up prism take suitable two kinds of technical schemes selecting progressive regional channel width L for use simultaneously.Accomplish to make teenager wearer to alleviate eye fatigue effectively technically, correct its wrong read-write posture, finally reach the purpose that makes its myopia be prevented or delay to deepen.

The present invention has easy to process, can reach following purpose after the teenager wears:

(1) corrects the write-read posture;

(2) near far away shallow with district's number of degrees with the district, reduce eyes and regulate tired;

(3) degree that prevention, control myopia are deepened.

Fig. 1: be prior art of the present invention;

Fig. 2: be prior art of the present invention plane mark synoptic diagram;

Fig. 3: be prior art side view of the present invention;

Fig. 4: be the synoptic diagram of summit behind the lens to eyes cornea distance;

Fig. 5: it is near with zone use synoptic diagram when wearing identical glasses for the adult with the teenager;

Fig. 6: wear the synoptic diagram of upwards lifting lens when prior art product of the present invention is corrected for the teenager;

Fig. 7: be end prism imaging synoptic diagram down;

Fig. 8: be plane of the present invention mark synoptic diagram;

Fig. 9: be end prism imaging synoptic diagram up.

Set forth most preferred embodiment of the present invention below in conjunction with accompanying drawing:

Certain student 14 years old, right and left eyes is-5.00 degree myopia.This student before 2 years myopia be-3.00 degree, and eye hygiene custom is bad, reading/writing distance has only 20 centimetres, with long between at the moment, regulate with convergence excess be the main cause that its myopic degree is deepened.Can be formulated as follows the eyeglass lens with gradually progressive focal length of prescription for this student to this situation: far away with district's number of degrees-5.00, near with district's number of degrees-3.50, correct defects of vision is 1.0, additional number of degrees ADD is+1.50D, Pd (interpupillary distance) is 63mm, and PH (pupil height) is 26mm, and the mirror holder height is 40mm, lens is got CR-39 animi resin material, gets d=2mm.With its carry out slightly, fine lapping processing, make prism degree p=0.2cm * 5=1 △, progressive regional channel width L is 5-6mm.

This student expands the pupil optometry again through after the wearing of 1 year gradually progressive focal length glasses, and right and left eyes myopia-5.25 degree is deepened 0.25 degree than right and left eyes-5.00 degree myopia the year before, is 1/4th of former intensification speed.And eye fatigue disappears, and read-write posture is corrected (reading/writing distance 30-35 centimetre).

Claims (2)

1. eyeglass lens with gradually progressive focal length, by far away with the zone, closely constitute with zone, progressive zone, fuzzy region.It is suitable to d that main reference point (geometric center point) the B point that it is characterized in that lens vertically moves down, and d is greater than zero and less than 3 millimeters.The equidistant B point of shifting to of lens assembling "+" line point of crossing c.

2. a kind of eyeglass lens with gradually progressive focal length according to claim 1, it is characterized in that progressive regional channel width L can for:

When additional number of degrees ADD is+1.00D L=7.5mm-8.5mm;

When additional number of degrees ADD is+1.50D L=5.0mm-6.0mm;

When additional number of degrees ADD is+2.00D L=3.0mm-4.0mm;

When additional number of degrees ADD is+2.50D L=2.0mm-3.0mm.

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