WO2001051888A1 - Measurement of back radius of curvature and center material thickness of a contact lens in solution - Google Patents
Measurement of back radius of curvature and center material thickness of a contact lens in solution Download PDFInfo
- Publication number
- WO2001051888A1 WO2001051888A1 PCT/US2001/001017 US0101017W WO0151888A1 WO 2001051888 A1 WO2001051888 A1 WO 2001051888A1 US 0101017 W US0101017 W US 0101017W WO 0151888 A1 WO0151888 A1 WO 0151888A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- lens
- ultrasound wave
- accordance
- reflected
- curvature
- Prior art date
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
- G01M11/02—Testing optical properties
- G01M11/0207—Details of measuring devices
- G01M11/0214—Details of devices holding the object to be tested
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B17/00—Measuring arrangements characterised by the use of infrasonic, sonic or ultrasonic vibrations
- G01B17/02—Measuring arrangements characterised by the use of infrasonic, sonic or ultrasonic vibrations for measuring thickness
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B17/00—Measuring arrangements characterised by the use of infrasonic, sonic or ultrasonic vibrations
- G01B17/06—Measuring arrangements characterised by the use of infrasonic, sonic or ultrasonic vibrations for measuring contours or curvatures
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
- G01M11/02—Testing optical properties
- G01M11/0242—Testing optical properties by measuring geometrical properties or aberrations
- G01M11/025—Testing optical properties by measuring geometrical properties or aberrations by determining the shape of the object to be tested
Definitions
- the present invention relates generally to field of contact lenses, and more particularly to the measurement of the front radius of curvature, back radius of curvature and center material thickness of a contact lens in solution
- U S Patent No 5,062,297 discloses a method of measuring a profile of an object, wherein an ultrasonic wave is radiated from an ultrasonic transducer toward an object supported by a supporting member in water, and a wave reflected at the surface of the object is detected by the transducer
- the method disclosed in the patent requires that the transducer be moved to different measurement points to obtain multiple profiles in order to generate average BC, FC & BC SAG and is therefore inefficient
- This measurement technique is inefficient in that it requires repeated parameter measurements that result in increased costs
- the patented method uses a diffused ultrasound beam that is more susceptible to changes in the curvature of the lens and thus, is not suitable for use with a tone lens
- FIG. 1 diagrammatically depicts an example measuring system in accordance with the present invention.
- Figure 2 diagrammatically depicts a top view of the support member of Figure 1
- the present invention is directed to a method and device for simultaneously measuring the center material thickness and back radius of curvature of a lens, and in particular a tone lens
- An ultrasound wave is radiated by a transducer towards a lens and, in turn, reflected off of the front and back surfaces of the lens Voltage-versus-time waveforms are generated based on the output of the transducer in response to the received reflected ultrasound waves
- the center material thickness is determined by measuring the lapse in time between receipt at the transducer of the reflected waveform off of the first surface and the reflected waveform off of the second surface of the lens Based on the lapse in time the center material thickness may be determined using a look-up table or database that accounts for the speed of sound in the lens material at the current experimental temperature
- the sagittal height is measured by first detecting the time lapse between a reflected ultrasound wave, or echo, off of the first surface of the lens and the echo of a reference plane membrane below the lens
- the reference plane may be a physical membrane or alternatively a
- a containing means 1 such as a bowl, is supported by a base 18 Ring 17 preferably is interposed between the bowl and the base to prevent slippage
- the containing means 1 includes outer and inner fluid reservoirs, depicted in Figure 1 as outer reservoir 19 and an inner reservoir 20
- the inner reservoir 20 is filled with a first fluid 23a, such as a buffered saline solution
- Outer reservoir 19 is covered by a lid 16 and filled with a thermal transfer medium 23b, for example distilled water, maintained at a substantially constant temperature to stabilize the temperature of an object under test 2 and a transducer 3
- a lid or cover 22 is placed over the lid 16 and interior container 20 during measurement of the material under test 2
- lid 22 includes a knob 25 for facilitating its removal and placement on and off of the containing means 1
- the transducer 3 is disposed in a casing 29 along with a delay media/filter 28 and a focusing or acoustic lens 30 The focusing lens narrows the beam to
- the outer reservoir 19 has a support member 21 , such as a conically tapered pedestal with a passage or channel 21 a defined longitudinally therethrough, projecting upwards into the inner reservoir 20
- An annular groove or ridge 27b is defined in the top surface of the holder 27, as shown in Figure 2
- One or more radial slots 27c are defined in the groove 27b to allow the free flow or passage of the first fluid 23a between the inner reservoir 20 and channel 21 a
- an annular ridge may be used with one or more radial slots defined therein
- Multiple holding means are provided, each having a different diameter annular groove 27b The operator selects a particular holding means 27 based on the diameter of the contact lens under test
- a holder 27 is selected having an annular groove 27b of sufficient dimension so that when placed therein the lens 2 has negligible, if any, tolerance to move This ensures that the ultrasound beam will strike substantially perpendicular to an incident surface of the lens
- the object under test 2 for example, a tone contact lens
- the contact lens 2 is preferably allowed to settle into place for a predetermined period of time, preferably approximately 10 seconds, so as to come to rest in the groove 27b
- the transducer 3 is disposed below the support member 21 with its side walls surrounded by the outer reservoir 19 so that the thermal transfer medium 23b stabilizes the temperature of the transducer
- the lens 2 is placed approximately 67 mm away from the focal point of the transducer Securing means 24, such as O- ⁇ ngs, are interposed between the transducer 3 and outer reservoir 19
- the first fluid 23a from the inner reservoir 20 passes freely through the permeable contact lens 2 and slots 27c defined in the holder 27 and into the channel 21 a, but does not mix or exchange with the thermal transfer medium 23b
- transducer 3 radiates ultrasound waves generated by an ultrasound voltage pulse generator 4, such as a pulser, towards the lens 2 which, in turn, are reflected off the surface of the lens and received by the transducer
- the pulser may pulses between approximately 1 to approximately 10,000 times per second, with each pulse signal having a frequency from approximately 5 MHz to approximately 100 MHz
- the lens 2 has a first surface (closest to the transducer 3) and a second surface (furthest away from the transducer 3) Each surface produces a reflected ultrasound wave
- a timing gate 5 is connected to the ultrasound voltage pulse generator 4 and synchronized with the pulse signal or main bang Gate 5 is also connected to processors 8, 10, limiting the processing of return signals from transducer 3 to include only ultrasound waves reflected off of one or both of the surfaces of the lens 2, and suppress those waves reflected
- a voltage is used to drive the transducer crystal or polymer Specifically, the applied voltage has a piezoelectric effect causing the transducer to become deformed and transmit an ultrasound wave
- the wave passes through the solution or interface between the transducer 3 and material under test 2
- a portion of the ultrasound wave is reflected off of the first surface of the lens while the remaining portion of the wave passes through the lens 2 and is reflected off of the second surface
- Each reflected ultrasound wave impacts and deforms the transducer 3 thereby changing its associated voltage over time, which may be represented as a voltage versus time waveform
- the voltage output from the transducer is reproduced by a splitter 26 and transmitted to a first receiver 6 for determining the material center thickness (MT) and a second receiver 7 for determining water path (WP), from which the BC SAG may be derived
- Receivers 6, 7 measure the voltage output of the transducer over time to generate MT and WP waveforms, respectively
- Each surface of the lens produces an associated reflected ultrasound wave that is represented by a
- a physical reference plane structure for example, a plastic plate
- the reference plate is preferably made of a material having substantially the same acoustic impedance as the lens polymer under test This is advantageous because the reflection amplitude depends on the difference between the immersion fluid and the reflective object at the interface between the two materials Since the amplification gain circuit 9 shifts the electrical waveform in time to a different degree for signals which are not of equivalent amplitude, a more accurate results will be realized if the reference plate and lens under test have substantially equivalent acoustic impedance
- an aluminum plate is not very desirable, while a glass plate is preferred, and a hydrophobic plastic, such as an oriented polyolefin is more preferred
- R is the back radius of curvature
- h is the sagittal height of the object.
- the chord C represents the fixed artificial reference plane at the ends of the contact lens, e g the diameter of the lens as long as the support 27 intersects with the edge of the lens If the lens under test is a Tone lens having two radii, then plugging in the known variables in equation (1 ) and solving for the radius R results in a generated value representing the effective or average BC SAG of the two radii
- a LUT or database is generally used to determine the effective or average BC SAG based on the SAG height
- a first automatic gain control (AGC) 9 is connected via a feedback loop between the first processor 8 and the first receiver 6
- a second automatic gain control (AGC) 1 1 is connected via a feedback loop between the second processor 10 and the second receiver 7
- the AGC circuits 9, 1 1 are used to change the signal gam when the ultrasound beam radiated from the transducer does not strike substantially perpendicular to the incident surface of the lens or if the acoustic impedance of the lens yields a weaker or stronger echo
- the AGC compensates for the narrow dynamic range of the receiver/processor
- the first processor 8 is connected to a first display 12 and first alarm or indicator 13, while the second system logic circuit 10 is connected to a second display 14 and second alarm or indicator 15
- An operator is able to view the results on the display If the ultrasound does not strike substantially perpendicular to the incident surface of the lens and is below a predetermined minimum threshold level which may be compensated for by adjusting the gam, the alarm or indicator 13, 15 is activated instructing the operator to adjust the position of the lens on the support member
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Geometry (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Length Measuring Devices Characterised By Use Of Acoustic Means (AREA)
- Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
- Length Measuring Devices With Unspecified Measuring Means (AREA)
- Testing Of Optical Devices Or Fibers (AREA)
- Eyeglasses (AREA)
Abstract
Description
Claims
Priority Applications (7)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
BR0104049-9A BR0104049A (en) | 2000-01-14 | 2001-01-11 | Measurement of posterior radius of curvature and central material thickness of a contact lens in solution |
AU30918/01A AU3091801A (en) | 2000-01-14 | 2001-01-11 | Measurement of back radius of curvature and center material thickness of a contact lens in solution |
KR1020017011701A KR20020006029A (en) | 2000-01-14 | 2001-01-11 | Measurement of back radius of curvature and center material thickness of a contact lens in solution |
JP2001552054A JP2003519787A (en) | 2000-01-14 | 2001-01-11 | Apparatus and method for measuring lens characteristics |
EP01903048A EP1169615A1 (en) | 2000-01-14 | 2001-01-11 | Measurement of back radius of curvature and center material thickness of a contact lens in solution |
CA002366499A CA2366499A1 (en) | 2000-01-14 | 2001-01-11 | Measurement of back radius of curvature and center material thickness of a contact lens in solution |
HK02102607.9A HK1041043A1 (en) | 2000-01-14 | 2002-04-08 | Measurement of back radius of curvature and center material thickness of a contact lens in solution |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US48336300A | 2000-01-14 | 2000-01-14 | |
US09/483,363 | 2000-01-14 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2001051888A1 true WO2001051888A1 (en) | 2001-07-19 |
Family
ID=23919758
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US2001/001017 WO2001051888A1 (en) | 2000-01-14 | 2001-01-11 | Measurement of back radius of curvature and center material thickness of a contact lens in solution |
Country Status (10)
Country | Link |
---|---|
EP (1) | EP1169615A1 (en) |
JP (1) | JP2003519787A (en) |
KR (1) | KR20020006029A (en) |
CN (1) | CN1364231A (en) |
AU (1) | AU3091801A (en) |
BR (1) | BR0104049A (en) |
CA (1) | CA2366499A1 (en) |
HK (1) | HK1041043A1 (en) |
TW (1) | TW484007B (en) |
WO (1) | WO2001051888A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2090229A1 (en) * | 2008-02-16 | 2009-08-19 | Technische Universität Dresden | Assembly and method for determining the combination of curvature radii and distances to acoustic boundary areas in test objects using ultrasounds |
CN112985228A (en) * | 2021-02-05 | 2021-06-18 | 西安应用光学研究所 | Optical element center thickness precision measurement appearance of quick centering |
CN118408477A (en) * | 2024-06-28 | 2024-07-30 | 北京特思迪半导体设备有限公司 | Displacement sensor structural parameter adjusting method, liquid environment control method and device |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN101283260B (en) * | 2005-10-13 | 2011-07-27 | 诺瓦提斯公司 | Cuvette for optical inspection of free floating ophthalmic lenses |
AR064643A1 (en) * | 2006-12-21 | 2009-04-15 | Univ Arizona | OPTICAL LENS TRAY |
CN108734766B (en) * | 2018-05-17 | 2022-04-08 | 业成科技(成都)有限公司 | Method for evaluating curvature radius of curved surface device |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS61195327A (en) * | 1985-02-26 | 1986-08-29 | Asahi Optical Co Ltd | Lens meter with measurement mechanism for radius of curvature |
EP0357905A2 (en) * | 1988-08-16 | 1990-03-14 | Toray Industries, Inc. | Method of measuring a profile of an object and an apparatus for carrying out the method |
EP0766063A2 (en) * | 1995-09-29 | 1997-04-02 | JOHNSON & JOHNSON VISION PRODUCTS, INC. | Lens parameter measurement using optical sectioning |
-
2001
- 2001-01-11 CA CA002366499A patent/CA2366499A1/en not_active Abandoned
- 2001-01-11 WO PCT/US2001/001017 patent/WO2001051888A1/en not_active Application Discontinuation
- 2001-01-11 EP EP01903048A patent/EP1169615A1/en not_active Withdrawn
- 2001-01-11 KR KR1020017011701A patent/KR20020006029A/en not_active Application Discontinuation
- 2001-01-11 AU AU30918/01A patent/AU3091801A/en not_active Abandoned
- 2001-01-11 CN CN01800458A patent/CN1364231A/en active Pending
- 2001-01-11 JP JP2001552054A patent/JP2003519787A/en active Pending
- 2001-01-11 BR BR0104049-9A patent/BR0104049A/en not_active Application Discontinuation
- 2001-03-28 TW TW090100665A patent/TW484007B/en active
-
2002
- 2002-04-08 HK HK02102607.9A patent/HK1041043A1/en unknown
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS61195327A (en) * | 1985-02-26 | 1986-08-29 | Asahi Optical Co Ltd | Lens meter with measurement mechanism for radius of curvature |
EP0357905A2 (en) * | 1988-08-16 | 1990-03-14 | Toray Industries, Inc. | Method of measuring a profile of an object and an apparatus for carrying out the method |
EP0766063A2 (en) * | 1995-09-29 | 1997-04-02 | JOHNSON & JOHNSON VISION PRODUCTS, INC. | Lens parameter measurement using optical sectioning |
Non-Patent Citations (1)
Title |
---|
PATENT ABSTRACTS OF JAPAN vol. 011, no. 022 (P - 538) 21 January 1987 (1987-01-21) * |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2090229A1 (en) * | 2008-02-16 | 2009-08-19 | Technische Universität Dresden | Assembly and method for determining the combination of curvature radii and distances to acoustic boundary areas in test objects using ultrasounds |
CN112985228A (en) * | 2021-02-05 | 2021-06-18 | 西安应用光学研究所 | Optical element center thickness precision measurement appearance of quick centering |
CN112985228B (en) * | 2021-02-05 | 2024-02-27 | 西安应用光学研究所 | Quick centering optical element center thickness precision measuring instrument |
CN118408477A (en) * | 2024-06-28 | 2024-07-30 | 北京特思迪半导体设备有限公司 | Displacement sensor structural parameter adjusting method, liquid environment control method and device |
Also Published As
Publication number | Publication date |
---|---|
KR20020006029A (en) | 2002-01-18 |
AU3091801A (en) | 2001-07-24 |
BR0104049A (en) | 2001-12-18 |
HK1041043A1 (en) | 2002-06-28 |
EP1169615A1 (en) | 2002-01-09 |
CN1364231A (en) | 2002-08-14 |
JP2003519787A (en) | 2003-06-24 |
CA2366499A1 (en) | 2001-07-19 |
TW484007B (en) | 2002-04-21 |
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