Performance specification table
Item

Speciﬁcations① Measurement lens shape

Convexity, meniscus (both spherical and aspherical)② Measurement range (MAX)

Convex surface up to 50mm / Concave surface (including meniscus) up to 30mm

③ Measurement range (MIN)

Up to 90 μm④ Measurable φ

10 to 100 mm (φ10 or less can be handled with a dedicated holder)⑤ ΔH

Up to approx. 10 mm⑥ Measurement accuracy (precision)<±2μm compared to the steel ball master instrument⑦ Measurement accuracy (repeatability)

Variation in 25 measurements <±2 μm⑧ Equipment dimensions (main unit)

W ２９５ｘＤ５０５ＸＨ５０３（ｍｍ）⑨ Equipment dimensions (control box)

W２２０ｘD４８０XH５０８（ｍｍ）⑩ Displacement Gauge

CL-3000 Multicolor Laser Coaxial Displacement Transducer manufactured by

Seek and measure lens cener thickness
only an exact point you need

Keyence Corporation⑪ Weight

Main unit (approx. 33kg) + Electrical box (approx. 25kg) Total: approx. 58kg

⑫ Power consumption

６A/６００W*Steel ball master sold separately (1", 1/2", with measurement data)◆ Manufacturer

G-Freude Co., Ltd.
203 Itabashi Hilltop Mansion
2-20-5, Itabashi, Itabashi-ku, Tokyo 173-0004
Phone: +81-3-6905-7575 Fax: +81-3-6905-7576
URL: https://www.g-freude.co.jp◆ Distributor

Nagata Co., Ltd.
Headquarters
2-4-15 Daiei-cho, Okaya City, Nagano 394-0025 Japan
Tel : +81 266-22-4592 (Main) Fax : +81 266-24-0317
Mail : inf@nagata-ss.co.jp

Tokyo Office
5-27-10 Owada-cho, Hachioji City,
Tokyo 192-0045 Japan
Tel : +81 42-631-1782 Fax : +81 42-631-1786

Utsunomiya Office43-102 Hiraide-Kogyo-Danchi, Utsunomiya City,
Tochigi 321-0905 Japan
Tel : +81 28-613-0255 Fax : +81 28-613-0277

Osaka Office
Shinko Kensetsu bldg. 405, 2-11 Kaimei-cho,Amagasaki City, Hyogo 660-0862 Japan
Tel : +81 6-6430-0125 Fax : +81 6-6430-0135

Oita Office
4-1 Kitaju, Beppu City, Oita 874-0845 Japan
Tel : +81 977-76-8201 Fax : +81 977-76-8202

Nagata (Hong Kong) Co., Ltd.
Ctr.,2-16 Kwai Fung Crescent, Kwai Chung, NT, HK
Tel ：+852 2614-7755 Fax : +852 2614-7767
Mail : info@nagata.com.hk

Nagata (Shanghai International) Trade Co., Ltd.
Hankou Road,Huang Pu Dist. Shanghai
Tel ：+86 21-6360-1527 Fax : +86 21-6360-1608
Mail : ekinlin@nagata-ss.co. jp / liupeisheng@nagata-ss.co. jp

Indonesia Jakarta Office
Jl. Raya Sukabumi, Ciawi, Bogor, Jawa Barat, Indonesia
Tel ：+62 812-941-0760
Mail : shimazu@nagata-opto.co.id

Non-contacting
Lens Center Thickness Gauge

Mastering the Measurement of Lens Center Thickness

1

Non-contact automatic measurement
without touching the lens

Although the center thickness of the lens is clearly indicated on thedesign drawing, it is diﬃcult to measure accurately, and the "contacttype" device is the mainstream. The accuracy of the "contact type"
depends on the mechanical structure, and "measurement scratch" isalso an issue.
Accurate and automatic “non-contact" measurement would be an ideal.
This machine was developed in response to such requests.

Keyence Displacement Transducer

Principle and method of measurement
Displacement gauge
Encoder

In XY stage,
vertex detection scan

Encoder
displacement
WD（UP）
Block gauge

T=T0（Given）

WD（Down ）Lens center
thickness

Encoder
displacement

Measurement
range
Measurement
range

What is lens center thickness?
The displacement transducer slides
smoothly up and down along the two LM
guides located on the back plate of the
instrument. In addition, the combination of
the displacement transducer's own
measurements and the LM guides allows
the system to handle a wide range of lens
thickness changes.

Lens center thickness = Block gauge thickness ± Encoder displacement ± Measurement of Displacement Sensor"Measure the center thickness of the lens without touching it,
regardless of the "refractive index" or "radius of curvature.

2

Automatic vertex detection andfast scan measurement

Automatically detects vertices by automatically scanning an
arbitrary measurement range.This feature eliminates the need forcentering of the lens. In addition, the input of "refractive index"
and “the radius of curvature” of the material is not required.

Lens vertex detection method

Measurement range of the adopted displacement transducer
in the Z direction = WD ±1.3 mm.
The scanning XY stage calculates all center thicknesses
within the measurement range and automatically detects thecenter thickness at its maximum (minimum) value.
WD (15ｍｍ）
Center thickness

Arbitrary measurement range

Center thickness

Automatic scan in the XY stage

line scan method
The measurement data captured by the linear motionof the stage is once imported to the PC side forhigh-speed calculation processing and 3D analysis.

High-speed scan

＋1.3mmStage

3

Cross-sectional image of
concave measurement

Measuring point

3D map display to capture visually

If the output is only numerical values, it is diﬃcult to know if the surface
vertex is really captured. Therefore, this system outputs a 3D map foreach measurement to visually enhance the reliability of the measurement.

Display of 3D maps
It is possible to display the front and back sides simultaneously.
It is also possible to use the scroll function to rotate the 3D map
and display the coordinates of the vertices.
23

Mastering the Measurement of Lens Center Thickness

1

Non-contact automatic measurement
without touching the lens

Although the center thickness of the lens is clearly indicated on thedesign drawing, it is diﬃcult to measure accurately, and the "contacttype" device is the mainstream. The accuracy of the "contact type"
depends on the mechanical structure, and "measurement scratch" isalso an issue.
Accurate and automatic “non-contact" measurement would be an ideal.
This machine was developed in response to such requests.

Keyence Displacement Transducer

Principle and method of measurement
Displacement gauge
Encoder

In XY stage,
vertex detection scan

Encoder
displacement
WD（UP）
Block gauge

T=T0（Given）

WD（Down ）Lens center
thickness

Encoder
displacement

Measurement
range
Measurement
range

What is lens center thickness?
The displacement transducer slides
smoothly up and down along the two LM
guides located on the back plate of the
instrument. In addition, the combination of
the displacement transducer's own
measurements and the LM guides allows
the system to handle a wide range of lens
thickness changes.

Lens center thickness = Block gauge thickness ± Encoder displacement ± Measurement of Displacement Sensor"Measure the center thickness of the lens without touching it,
regardless of the "refractive index" or "radius of curvature.

2

Automatic vertex detection andfast scan measurement

Automatically detects vertices by automatically scanning an
arbitrary measurement range.This feature eliminates the need forcentering of the lens. In addition, the input of "refractive index"
and “the radius of curvature” of the material is not required.

Lens vertex detection method

Measurement range of the adopted displacement transducer
in the Z direction = WD ±1.3 mm.
The scanning XY stage calculates all center thicknesses
within the measurement range and automatically detects thecenter thickness at its maximum (minimum) value.
WD (15ｍｍ）
Center thickness

Arbitrary measurement range

Center thickness

Automatic scan in the XY stage

line scan method
The measurement data captured by the linear motionof the stage is once imported to the PC side forhigh-speed calculation processing and 3D analysis.

High-speed scan

＋1.3mmStage

3

Cross-sectional image of
concave measurement

Measuring point

3D map display to capture visually

If the output is only numerical values, it is diﬃcult to know if the surface
vertex is really captured. Therefore, this system outputs a 3D map foreach measurement to visually enhance the reliability of the measurement.

Display of 3D maps
It is possible to display the front and back sides simultaneously.
It is also possible to use the scroll function to rotate the 3D map
and display the coordinates of the vertices.
23

In search of "accurate measurement precision”

1Comparative measurement witha block gauge built into the device

The way to increase the accuracy is to calibrate the instrument
more often. This instrument has a built-in ceramic block gauge,
which is programmed to automatically calibrate itself ﬁrst before
starting the actual measurement. Since the measurement is"reﬂective", it does not depend on the refractive index of the lens.

Verification of accuracy
WD

Principle of Master Steel Ball Measurement
A measuring machine needs a master plate called “Master”, but there is nomaster plate for this measurement. The reason for this is that there is no
exact method for measuring the center thickness. Therefore, the accuracyof the center thickness measurement can be demonstrated by measuring
the diameter of a steel ball with ultra-high precision (right ﬁgure).

Measurement value

Comparative verification by steel ball measurement
The ﬁgure below shows the Master Steel Ball, which is the manufacturing
standard for steel balls used in slide bearings, and its certiﬁcate and thedata measured by this device.

Master steel ball: 1/2 inch = 12.70000mm

WD

The length of the green line :diameter of the steel ballCT-gauge: 12.7001mm in average (error is +0.1μ)Opening up new possibilities for lenses
with unprecedented new measurement standards

2

Mechanical mechanism to measure the center thickness of the lens correctly

In lens measurement, a "yatoi" is often used, but it is costly and time-consuming to manufacture one for each measurement. In thissystem, a lens holding mechanism that does not use a tool is available. In addition, orthogonality between the measurement lightand the sample is important to measure the center thickness accurately with the reﬂection type.

Sample chucking mechanism
The lens holding mechanism is a V-shaped
support made of Delrin material that can holdany diameter. Also, automatic vertex detection
eliminates the need for centering and holding.
Available in diameters from 10 to 100 mm.
Individual holder is required for φ10 or less.

4

Check the level on a 3D map.
Use the parallel plane plate to adjust the level of the sample
holding surface.

Upper side : Lens 1

Upper side : Lens 1

Bottom side: Lens 1

Bottom side: Lens 1

Before tilt adjustment

After tilt adjustment

5

In search of "accurate measurement precision”

1Comparative measurement witha block gauge built into the device

The way to increase the accuracy is to calibrate the instrument
more often. This instrument has a built-in ceramic block gauge,
which is programmed to automatically calibrate itself ﬁrst before
starting the actual measurement. Since the measurement is"reﬂective", it does not depend on the refractive index of the lens.

Verification of accuracy
WD

Principle of Master Steel Ball Measurement
A measuring machine needs a master plate called “Master”, but there is nomaster plate for this measurement. The reason for this is that there is no
exact method for measuring the center thickness. Therefore, the accuracyof the center thickness measurement can be demonstrated by measuring
the diameter of a steel ball with ultra-high precision (right ﬁgure).

Measurement value

Comparative verification by steel ball measurement
The ﬁgure below shows the Master Steel Ball, which is the manufacturing
standard for steel balls used in slide bearings, and its certiﬁcate and thedata measured by this device.

Master steel ball: 1/2 inch = 12.70000mm

WD

The length of the green line :diameter of the steel ballCT-gauge: 12.7001mm in average (error is +0.1μ)Opening up new possibilities for lenses
with unprecedented new measurement standards

2

Mechanical mechanism to measure the center thickness of the lens correctly

In lens measurement, a "yatoi" is often used, but it is costly and time-consuming to manufacture one for each measurement. In thissystem, a lens holding mechanism that does not use a tool is available. In addition, orthogonality between the measurement lightand the sample is important to measure the center thickness accurately with the reﬂection type.

Sample chucking mechanism
The lens holding mechanism is a V-shaped
support made of Delrin material that can holdany diameter. Also, automatic vertex detection
eliminates the need for centering and holding.
Available in diameters from 10 to 100 mm.
Individual holder is required for φ10 or less.

4

Check the level on a 3D map.
Use the parallel plane plate to adjust the level of the sample
holding surface.

Upper side : Lens 1

Upper side : Lens 1

Bottom side: Lens 1

Bottom side: Lens 1

Before tilt adjustment

After tilt adjustment

5Other measurements and functions in"Expanding Possibilities”

1

Comparison of "contact" and "non-contact" data
Measurement examples and data comparison① Double concave lensSmall diameter lens measurement function
Small diameter lens measurement

CT measurement conditions

For small-diameter lenses such as those used in
microscopes, even the slightest center thickness error
is severe. This system uses a dedicated holder thatenables accurate measurement.
The ﬁgure on the right shows the results of hemisphericallens measurement with a diameter of 3 mm.

2

Measurement of hemispherical lens of 3 mm diameterContact measurement

Measuring machine for large diameter*Special specification

High-speed center thickness measuring machine*Currently under development

The center thickness of lenses for semiconductor
lithography equipment is in the 100mm class. In
addition, the cost of glass material is high, so
high-precision non-contact measurement is essential.

In order to meet the demands of a measurement with a more
focus on a higher speed than accuracy" and "additional
measurement of the outer diameter", a new measuring system
has been developed.
The project is scheduled for completion by the end of 2021.

In the past, there was no way to measure theamount of ΔH in a "non-contact" manner, andthe only way to do so was to use a depth gauge.

Sample lensVertexＷＤ

Ｓａｇ Value（⊿Ｈ）
XY ScanＷＤ

Shape：Meniscus lens φ57mm
Measurement range: 4mm square scan
Scan pitch: 0.4 mm
Number of points measured : 121 points
Measurement time: 17 seconds

Z displacement（⊿Ｚ）

Software that is easy to use and ingenious

Sample anti-collision software
Depending on the reﬂectivity of the sample, the displacementtransducer may move abnormally close to the sample. To prevent
this movement, the height information of the sample is input inadvance to prevent collision of the displacement transducer.

Inspection certiﬁcate
The system can create a pass/fail judgment report for sample
accuracy tolerance values required for production control.

Contact measurement data

: CT＝４.0５ｍｍ

Non-contact measurement（CT gauge） : CT＝４.0５０ｍｍ

Before correction

After correction

In the case of a small diameter lens with a small radius, thereﬂected light may not return properly depending on thestarting position of the scan. The stage side is equipped witha function to correct this slight misalignment.

6② Meniscus lensContact measurement

Sample centering correction function: CT＝2.03ｍｍ

CT measurement conditions

Parallel planar panel
Sample stage

XY StageContact measurement dataNon-contact measurement（CT gauge） : CT＝2.03１ｍｍ

Non-contact ΔH measurement function
ΔH measurement function

3

Holder mounted

Shape：Double concave lens φ40mm
Measurement range: 3mm square scan
Scan pitch: 0.3 mm
Number of points measured : 121 points
Measurement time: 15 seconds③ ΔH measurement
Front

Front

CT measurement conditions
Shape：Meniscus lens φ27.8 mm
Measurement range: 3mm square scan
Scan pitch: 0.3 mm
Number of points measured : 121 points
Measurement time: 14 seconds

Contact measurement

Zero reset: Sag＝０．
５１７ｍｍ

５１６ｍｍ
Non-contact measurement（CT gauge） : Sag＝０．

7

Other measurements and functions in"Expanding Possibilities”

1

Comparison of "contact" and "non-contact" data
Measurement examples and data comparison① Double concave lensSmall diameter lens measurement function
Small diameter lens measurement

CT measurement conditions

For small-diameter lenses such as those used in
microscopes, even the slightest center thickness error
is severe. This system uses a dedicated holder thatenables accurate measurement.
The ﬁgure on the right shows the results of hemisphericallens measurement with a diameter of 3 mm.

2

Measurement of hemispherical lens of 3 mm diameterContact measurement

Measuring machine for large diameter*Special specification

High-speed center thickness measuring machine*Currently under development

The center thickness of lenses for semiconductor
lithography equipment is in the 100mm class. In
addition, the cost of glass material is high, so
high-precision non-contact measurement is essential.

In order to meet the demands of a measurement with a more
focus on a higher speed than accuracy" and "additional
measurement of the outer diameter", a new measuring system
has been developed.
The project is scheduled for completion by the end of 2021.

In the past, there was no way to measure theamount of ΔH in a "non-contact" manner, andthe only way to do so was to use a depth gauge.

Sample lensVertexＷＤ

Ｓａｇ Value（⊿Ｈ）
XY ScanＷＤ② Meniscus lensShape：Meniscus lens φ57mm
Measurement range: 4mm square scan
Scan pitch: 0.4 mm
Number of points measured : 121 points
Measurement time: 17 seconds

Z displacement（⊿Ｚ）

Contact measurement

Before correction

Depending on the reﬂectivity of the sample, the displacementtransducer may move abnormally close to the sample. To prevent
this movement, the height information of the sample is input inadvance to prevent collision of the displacement transducer.

Inspection certiﬁcate
The system can create a pass/fail judgment report for sample
accuracy tolerance values required for production control.

: CT＝４.0５ｍｍ

After correction

In the case of a small diameter lens with a small radius, thereﬂected light may not return properly depending on thestarting position of the scan. The stage side is equipped witha function to correct this slight misalignment.

Sample anti-collision software

Contact measurement dataNon-contact measurement（CT gauge） : CT＝４.0５０ｍｍ

Software that is easy to use and ingenious
Sample centering correction function: CT＝2.03ｍｍ

CT measurement conditions

Parallel planar panel
Sample stage

XY StageContact measurement dataNon-contact measurement（CT gauge） : CT＝2.03１ｍｍ

Non-contact ΔH measurement function
ΔH measurement function

3

Holder mounted

Shape：Double concave lens φ40mm
Measurement range: 3mm square scan
Scan pitch: 0.3 mm
Number of points measured : 121 points
Measurement time: 15 seconds③ ΔH measurement
Front

Front

CT measurement conditions
Shape：Meniscus lens φ27.8 mm
Measurement range: 3mm square scan
Scan pitch: 0.3 mm
Number of points measured : 121 points
Measurement time: 14 seconds

Contact measurement

Zero reset: Sag＝０．
５１７ｍｍ

５１６ｍｍ
Non-contact measurement（CT gauge） : Sag＝０．

7
6

Performance specification table
Item

Speciﬁcations① Measurement lens shape

Convexity, meniscus (both spherical and aspherical)② Measurement range (MAX)

Convex surface up to 50mm / Concave surface (including meniscus) up to 30mm

③ Measurement range (MIN)

Up to 90 μm④ Measurable φ

10 to 100 mm (φ10 or less can be handled with a dedicated holder)⑤ ΔH

Up to approx. 10 mm⑥ Measurement accuracy (precision)<±2μm compared to the steel ball master instrument⑦ Measurement accuracy (repeatability)

Variation in 25 measurements <±2 μm⑧ Equipment dimensions (main unit)

W ２９５ｘＤ５０５ＸＨ５０３（ｍｍ）⑨ Equipment dimensions (control box)

W２２０ｘD４８０XH５０８（ｍｍ）⑩ Displacement Gauge

CL-3000 Multicolor Laser Coaxial Displacement Transducer manufactured by

Seek and measure lens cener thickness
only an exact point you need

Keyence Corporation⑪ Weight

Main unit (approx. 33kg) + Electrical box (approx. 25kg) Total: approx. 58kg

⑫ Power consumption

６A/６００W*Steel ball master sold separately (1", 1/2", with measurement data)◆ Manufacturer

G-Freude Co., Ltd.
203 Itabashi Hilltop Mansion
2-20-5, Itabashi, Itabashi-ku, Tokyo 173-0004
Phone: +81-3-6905-7575 Fax: +81-3-6905-7576
URL: https://www.g-freude.co.jp◆ Distributor

Nagata Co., Ltd.
Headquarters
2-4-15 Daiei-cho, Okaya City, Nagano 394-0025 Japan
Tel : +81 266-22-4592 (Main) Fax : +81 266-24-0317
Mail : inf@nagata-ss.co.jp

Tokyo Office
5-27-10 Owada-cho, Hachioji City,
Tokyo 192-0045 Japan
Tel : +81 42-631-1782 Fax : +81 42-631-1786

Utsunomiya Office43-102 Hiraide-Kogyo-Danchi, Utsunomiya City,
Tochigi 321-0905 Japan
Tel : +81 28-613-0255 Fax : +81 28-613-0277

Osaka Office
Shinko Kensetsu bldg. 405, 2-11 Kaimei-cho,Amagasaki City, Hyogo 660-0862 Japan
Tel : +81 6-6430-0125 Fax : +81 6-6430-0135

Oita Office
4-1 Kitaju, Beppu City, Oita 874-0845 Japan
Tel : +81 977-76-8201 Fax : +81 977-76-8202

Nagata (Hong Kong) Co., Ltd.
Ctr.,2-16 Kwai Fung Crescent, Kwai Chung, NT, HK
Tel ：+852 2614-7755 Fax : +852 2614-7767
Mail : info@nagata.com.hk

Nagata (Shanghai International) Trade Co., Ltd.
Hankou Road,Huang Pu Dist. Shanghai
Tel ：+86 21-6360-1527 Fax : +86 21-6360-1608
Mail : ekinlin@nagata-ss.co. jp / liupeisheng@nagata-ss.co. jp

Indonesia Jakarta Office
Jl. Raya Sukabumi, Ciawi, Bogor, Jawa Barat, Indonesia
Tel ：+62 812-941-0760
Mail : shimazu@nagata-opto.co.id

Non-contacting
Lens Center Thickness Gauge