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Claims  |
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What is claimed is:
1. The method of manufacturing a modular lens for eyeglasses, comprising:
determining the prescription required for the finished modular lens;
measuring the pupillary distance of the patient who will wear the
eyeglasses;
selecting a preground, prefinished, single vision lens having the spherical
and cylindrical power required by said prescription and having an optical
major reference point;
determining the decentration required to fit the selected single vision
lens to the patient;
selecting a prism wedge lens having the prism power required to produce the
required decentration of said major reference point of said single vision
lens; and
assembling said single vision lens and said prism wedge lens to produce a
surface finished modular lens having the required decentration.
2. The method of claim 1, wherein the step of assembling said single vision
and prism wedge lenses includes aligning said prism wedge lens with
respect to the cylinder axis of said single vision lens.
3. The method of claim 1, wherein the step of assembling said single vision
and prism wedge lenses includes the steps of
applying adhesive to one of said lenses;
aligning and angularly orienting said lenses with respect to each other;
and
curing said adhesive to bond said prism wedge lens to said single vision
lens.
4. The method of claim 1, further including:
selecting a frame having an opening for receiving said modular lens;
wherein the step of selecting a single vision lens includes selecting the
smallest diameter single vision lens that will cut out the size and shape
of said frame opening before decentration.
5. The method of claim 1, further including;
selecting at least one near-vision segment as required by said
prescription; and
assembling said segment to said prism wedge lens by aligning said segment
with respect to said decentered major reference point and adhesively
securing said segment to said prism wedge lens to form a multifocal lens.
6. The method of claim 1, further including edge grinding said finished
modular lens to fit a selected eyeglass frame.
7. The method of claim 3, further including:
selecting a frame having an opening for receiving said modular lens;
the step of selecting a single vision lens including determining the
smallest diameter single vision lens having the power required by said
prescription that will cut out to the size and shape of said frame opening
before decentration of said lens; and
edge grinding said modular lens to fit said frame opening.
8. The method of manufacturing a modular lens for eyeglasses comprising:
selecting from a stock of preground, prefinished single vision lenses
having various diameters and various spherical and cylindrical powers, the
single vision lens having the power required for the prescription to be
filled and having ( the smallest diameter that will fill the frame opening
in which the lens is to be mounted;
rotating the selected stock lens to orient the cylinder angle as required
by the prescription to be filled;:
selecting from a stock of prefinished prism wedges having different prism
powers, the prism wedge required to decenter said single vision lens by
the amount required for the frame in which the lens is to be mounted; and
assembling said single vision lens and said prism wedge lens to produce a
surface finished modular lens having the required prescription and
decentration.
9. The method of claim 8, further including edge grinding said assembled
modular lens to fit the frame opening in which the lens is to be mounted.
10. The method of claim 9, further including securing on said modular lens
a near-vision segment.
11. The method of manufacturing a prescription modular lens for eyeglasses,
comprising:
providing a multiplicity of preground, prefinished single vision stock
lenses each having a different known spherical and cylindrical powers and
different known diameters;
providing a multiplicity of prism wedge lenses having different known prism
powers;
determining for each of said single vision stock lenses the decentration of
its optical major reference point that will be produced by each of said
prism wedge lenses, whereby one of said prism wedge lenses can be selected
for combination with any selected single vision stock lens to produce a
desired decentration for the stock lens;
determining the prescription required by a patient for a finished modular
lens;
measuring the pupillary distance of the patient who will wear the
eyeglasses containing the finished modular lens;
determining the decentration required to fit the modular lens to the
patient;
selecting from said multiplicity of single vision stock lenses the lens
having the spherical and cylindrical power required by said prescription;
selecting from said multiplicity of prism wedge lenses the lens having the
prism power required to produce the required decentration of the major
reference point of the selected single vision stock lens; and
assembling said selected single vision stock lens and said selected prism
wedge lens to produce a surface finished modular lens having the required
decentration.
12. The method of claim 11, wherein data concerning said stock lenses, and
said prism wedge lenses, and the decentration provided by each combination
thereof, is stored in a computer memory for access for use in selecting
the lenses required for assembling a modular lens having a determined
prescription and decentration.
13. The method of claim 12, wherein the step of assembling a selected
single vision stock lens and a selected prism wedge lens includes;
aligning and angularly orienting said lenses with respect to each other to
produce the required decentration of the optical major reference point of
said single vision stock lens; and
bonding said prism wedge lens to said single vision stock lens.
14. The method of claim 12, further including:
selecting a frame having an opening for receiving said modular lens;
wherein the step of selecting a single vision stock lens includes
determining and selecting the smallest diameter single vision stock lens
that will cut out to the size and shape of said frame opening before
decentration.
15. The method of claim 12, further including:
storing, in a computer memory, data concerning the size and shape of the
lens openings for a multiplicity of eyeglass frame styles and sizes;
selecting a frame style and size for receiving said assembled modular lens;
producing from said stored frame data a frame pattern; and
edge grinding said modular lens, following said frame pattern.
16. A modular optical manufacturing system for producing from modular lens
components finished prescription eyeglass lenses, comprising:
data terminal means at a first location for receiving information
concerning the prescription of eyeglasses to be manufactured for a
patient, the size, style and manufacturer of the eyeglass frames selected
by the patient, and the pupillary distance between the pupils of the
patient's eyes;
computer means at a second location remote from said first location, said
computer including:
a. first storage means for receiving and storing frame pattern shape data
for a plurality of frames;
b. second storage means for receiving and storing modular lens data for use
in producing finished lenses from single vision elements and prism wedge
elements, the finished lenses having said prescription and each having a
major reference point which coincides with the location of a patient's
pupils;
said computer responding to information from said data terminal to provide
at said first location frame pattern data for the patient selected frame,
and modular lens data corresponding to the prescription and the pupillary
distance information;
pattern cutter means at said first location responsive to said frame
pattern data for producing a frame pattern having a size and shape equal
to the lens openings of said patient selected frame;
modular lens assembler means at said first location for assembling a
surface finished prescription lens from the single vision element and the
prism wedge element specified by the modular lens data provided by said
computer means; and
means for edge grinding said modular lens to the shape of said frame
pattern, whereby said modular lens is adapted to fit in said patient
selected frame. |
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Claims |
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Description |
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BACKGROUND OF THE INVENTION
The present invention relates, in general, to the manufacture of
prescription eyeglass lenses and, more particularly, to a unique method
and apparatus for accurately and rapidly manufacturing such lenses to
prescription through the assembly of modular components. The invention
further relates to a method and apparatus for identifying and assembling
component parts of a prescription lens and incorporates a method of edging
lenses to fit selected frames for complete eyeglass manufacture.
For over 100 years, the ophthalmic lens manufacturing industry has remained
static with eyeglass lenses being produced, using grinding and polishing
technology that has been available for most of that period. Although some
new lens materials have been introduced, such as plastics, and although a
small percentage of prescription lenses can be cast with the finished
optics, the vast majority of both glass and plastic lenses must still be
ground and polished, one at a time. This process involves so many
manufacturing steps that human error remains a large cost of doing
business.
Many attempts have been made to modernize the ophthalmic lens industry, but
the many failures are testimony to the fact that the production of quality
eyeglass optics is far more complicated than is generally imagined. There
are so many different prescriptions possible that most technological
innovations simply do not take into account all of the possibilities, and
thus are unacceptable.
One change that was made many years ago involved a shifting of the lens
manufacturing and lens edging steps away from the retail optometrist to
wholesale laboratories which are geared to large volume production of
prescription lenses. This shift was based almost solely on ecomonics,
since the cost of lens manufacturing equipment and inventory was so great
that it was beyond the reach of most retail operations that wished to
remain price-competitive. However, in giving up the manufacturing postion
of the business, the retail lens dispenser also gave up many desirable
features of his business, such as speed in meeting customer requirements
and detailed product control. Problems in communication to and from the
wholesaler, slow delivery times, the cost of double record keeping, the
cost of double overhead and the inflexibility of a wholesale manufacturing
operation were but a few of the problems created by this shift. The
problems encountered by wholesale manufacturers in meeting the needs of
the lens dispensers spurred the creation of "semi-finished" lens blank
manufacturers who supplied semi-finished blanks to the wholesalers,
creating yet another level of lost control and increased inventory
variability. This additional level in the process of supplying lenses
further compounded the problems noted above since such manufacturers
proceeded to expand the availability of semifinished lens blanks,
increasing the wholesalers inventory record keeping problems, and creating
additional complexities and costs.
Eyeglass frame manufacturers contribute to the problems which exist in the
industry since frame shapes and sizes are now dictated largely by fashion,
and thus are subject to constant change. Since the frame geometry, or
shape, always dictates the optical configuration of the prescription lens,
such geometry is a critical variable that must be precisely defined before
the lenses are produced. However, the huge number of frame shapes now
available on the market cannot be managed efficiently by even the largest
wholesale laboratories.
The present procedure for obtaining a pair of prescription eyeglasses
requires that the patient first have his or her eyes examined and
corrective lenses prescribed. An optician at the retail dispensary level
helps the patient select a suitable frame that is compatible with the
prescribed lenses and the distance between the patient's eyes is measured
so that the distance between the major reference points of the lenses,
when they are placed in the frames, will match the line of sight of the
patient's eyes. The optical prescription as well as data relating to the
style, size and shape of the frame is communicated to a wholesale
laboratory where the lenses are to be manufactured. In a small portion of
cases, the prescription can be produced from stock lenses often present at
the dispenser's location, but most prescriptions must be surfaced from a
blank. The prescription is verified by the wholesale laboratory and
optical computations are made to select the proper lens blanks for the
patient and for the selected frame so that the required frame shape can be
"cut out" from the surfaced blanks. The lens blanks are then pulled from
inventory and are mounted on blocks, or holders, which enable the blanks
to be mounted in lens grinding and polishing equipment. A grinding and
polishing tool, premanufactured to the compound curves required by the
particular prescription, is selected from inventory. This tool holds the
abrasive and polishing pads required to surface the lense through
oscillation on the surface of the lens blank to contour the lens surface
to the final compound curve geometry required by the prescription. A
number of steps are required, using finer and finer abrasives, to produce
the required high luster optical finish. This grinding and polishing
process is ordinarily done so as to properly relocate the optical center
of the lens from its geometric center to an offset location which
corresponds to the patient's line of sight through the frame. This
grinding to produce not only a prescription but decentration of the
optical center requires complex calculations and is a significant source
of error. Further, such grinding operation introduces distortions in the
lens, which is often a source of customer dissatisfaction.
Once the lens has been polished, it is optically measured for correctness
and then undergoes an edging process where the lens is geometrically
edge-shaped to fit the frame selected by the patient. This requires an
accurate location of the optical center of each lens of a pair with
respect to the frame so that the resultant lenses, when mounted, will fit
the patient. The completed spectacles are then optically and cosmetically
inspected and shipped to the dispenser. The dispenser confirms the
accuracy of the completed prescription and recalls the patient for fitting
and delivery.
The normal process described above takes several days to complete, even if
all of the necessary components are readily available at the laboratory.
If a lens blank or particular frame is not available, additional
delays--while the needed component is obtained from a manufacturer--are
encountered. Because of the reciprocal relationship between a dispenser
and a wholesale laboratory, there is a great redundancy in record keeping.
Furthermore, the time required for this process is objectionable to
everyone, particularly the patient, and all of the handling and record
keeping required is costly and inconvenient. Furthermore, the potential
for miscommunication is great and may result in conflict between the
dispenser/retailer and the wholesaler, or between the dispenser/retailer
and the patient, often leading to a loss of customers.
SUMMARY OF THE INVENTION
The present invention is directed to an apparatus and to a process for
manufacturing prescription lenses which will eliminate incompatible
retail-wholesale-patient relationships and which will enable prescription
lenses to be manufactured, edge-shaped, fitted to a frame, and delivered
to a patient, all at the dispenser/retail location and essentially while
the patient waits. In accordance with the invention, a simple and rapid
manufacturing procedure is provided which requires minimal capital
investment for the dispenser and which avoids the problems of record
keeping, communication, and multiple opportunities for human error that
occurs in present systems for prescription lens and eyeglass
manufacturing.
In accordance with the present invention, the entire manufacturing process
is carried out at the dispensing location, which may be a retail store,
where the patient is present and where all the information required for
preparing the eyeglasses is readily available. The invention requires the
availability at the dispensing location of some apparatus, which is
normally already available at such locations, as well as some additional
apparatus. Thus, there must be a selection of frames from which the
patient can choose, and normally there will be an inventory of stock
single vision lenses which would satisfy about 25% of the demand for
prescriptions. Also required would be a lens edger for shaping the
prescription optics to the shape of the frames selected by the patient.
Such lens edgers are standard equipment in most retail locations.
In addition to the foregoing, a retail location taking advantage of the
present invention would have an inventory of inexpensive modular lens
components from which prescription lenses may be assembled in the manner
to be described hereinbelow. In addition, a lens assembler, also to be
described, would be required together with a computer terminal to allow
communication with a central computer. Stored in the central computer is
data which identifies which modular lens components would be required to
construct a given prescription, plus frame pattern data corresponding to
eyeglass frame shapes. Also located at the dispensing location is a
pattern cutter which is responsive to information from the central
computer to produce a frame pattern which corresponds to the geometry of
the frame selected by the patient and which may be used in the lens edger
to edge-shape the completed lens to fit the frame.
With the foregoing apparatus available, the process of manufacturing and
fitting eyeglasses to a patient involves the usual measurements for the
prescription and for the frame, including a measurement of the patient's
pupilary distance to determine the location of the major reference points,
or the optical center of the lenses with respect to the geometric centers
of the frame openings in the selected frame. The information concerning
the optical prescription, and the size, style, and manufacturer of the
frame, is transmitted to a central computer. The computer then responds to
transmit to the dispensing location instructions for assembling specific
modular lens components to produce a lens with the required prescription
and with the optical center, or major reference point of the lens,
properly located for fitting the edge-finished lens into the selected
frame. The central computer also provides instructions for producing a
full-sized pattern shaped to fit the selected frame, which pattern is then
automatically cut on the pattern cutter while the specified modular lens
components are being assembled on the lens assembler device.
Premanufactured modular lens components are selected at the dispensing
location in accordance with the computer instructions and are laminated
together to form the desired lens. The completed lens is then edge-shaped
in the usual way in accordance with the pattern produced by the pattern
cutter, the lenses are mounted in the frame selected by the patient, and
the frame is fitted to the patient. All of this is done at the dispensing
location and may be accomplished while the patient waits, thus avoiding
the need for return visits by the patient.
The simplicity and desirability of the present invention is based on the
discovery that an extremely large number of complex lenses can be
constructed from a relatively small number of fundamental, modular
components. These components serve as building blocks for producing,
through modern lamination techniques, a wide variety of prescription
lenses. The modular components fall into a small number of categories, the
principal ones being:
(a) A simple, single-vision, sphero-cylindrical stock lenses which may have
positive or negative power and which are normally carried by most
wholesale laboratories and most dispenser/retail outlets;
(b) prism wedges which have no spherical or cylindrical power, but which
may be combined with sphero-cylindrical stock lenses to induce controlled
shifts of the optical centers thereof, or may be used to produce
prescribed prism effects in prescription lenses;
(c) bifocal or multifocal components which always contain a net positive
power and which may be attached to the surface of a lens to produce near
vision, or "reading" improvement; and
(d) "slab-off" prism wedges which are similar to (b) above, but are only
semicircular in shape. Such slab-off wedges may be used to correct the
prismatic imbalance which occur when a patient wears eyeglasses having two
lenses of greatly different power.
The foregoing optical modular components may be accurately and
inexpensively produced by mass production machinery. Only a relatively
small selection of optical values woul | | |
