Development of a noncontact optical sensor for measuring the shape of a surface and thickness of transparent objects

Ryu, Young Kee

doi:10.1117/1.1355260

Cited by 18 publications

(5 citation statements)

References 3 publications

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“…This technique, however, is relatively slow, provides no feedback and may experience an instrument drift error. Another solution to the problem is to utilize a 3D surface profile instrument to perform a surface profile measurement [ 13 , 16 , 19 , 25 ]. However, the high cost and complexity of such an instrument may make this technique impractical for routine production processes.…”

Section: Introductionmentioning

confidence: 99%

Development and Beam-Shape Analysis of an Integrated Fiber-Optic Confocal Probe for High-Precision Central Thickness Measurement of Small-Radius Lenses

Sutapun

Somboonkaew

Amarit

et al. 2015

Sensors

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This work describes a new design of a fiber-optic confocal probe suitable for measuring the central thicknesses of small-radius optical lenses or similar objects. The proposed confocal probe utilizes an integrated camera that functions as a shape-encoded position-sensing device. The confocal signal for thickness measurement and beam-shape data for off-axis measurement can be simultaneously acquired using the proposed probe. Placing the probe’s focal point off-center relative to a sample’s vertex produces a non-circular image at the camera’s image plane that closely resembles an ellipse for small displacements. We were able to precisely position the confocal probe’s focal point relative to the vertex point of a ball lens with a radius of 2.5 mm, with a lateral resolution of 1.2 µm. The reflected beam shape based on partial blocking by an aperture was analyzed and verified experimentally. The proposed confocal probe offers a low-cost, high-precision technique, an alternative to a high-cost three-dimensional surface profiler, for tight quality control of small optical lenses during the manufacturing process.

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Section: Introductionmentioning

confidence: 99%

Development and Beam-Shape Analysis of an Integrated Fiber-Optic Confocal Probe for High-Precision Central Thickness Measurement of Small-Radius Lenses

Sutapun

Somboonkaew

Amarit

et al. 2015

Sensors

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“…For, example, Surface reflectances have traditionally been made with purpose-built devices known as gonioreflectometers [3], which are rare and expensive. Regarding the refractive index, which is typical optical properties of a transparent object, there are many methods available for measurement [4]- [6]. However, their methods are completely differ form both the geometrical properties and surface reflectance.…”

Section: Introductionmentioning

confidence: 99%

Measurement method of optical properties by use of a rangefinder

Ohtani

Narita²,

Baba

2007

SICE Annual Conference 2007

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We here propose a new laser rangefinder, which can determine both the geometrical property and optical properties. The feature of this rangefinder is to equip an image sensor which has the ability of simultaneously detecting the position of a light and the incident angle onto the sensor. As a result, this rangefinder can determine the 3D shape of an object, which is geometrical property, and the surface reflectance of a specular object and the refractive index of a transparent object, which are optical properties.

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“…A charge-coupled device (CCD) camera captured the diffraction image with a 4 × 4 matrix of light spots from the top and bottom surfaces of the glass. Ryu et al [14] a noncontact optical sensor to measure the thickness of transparent plates by using a hologram laser unit. Liu et al [15] developed a transmission-type optical measuring system based on an astigmatic optical design for thickness measurements of glass.…”

Section: Introductionmentioning

confidence: 99%

A simple technique for measuring thickness distribution of transparent plates from a single image by using the sampling moiré method

Ri¹,

Muramatsu²

2010

Meas. Sci. Technol.

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A simple measurement technique for the thickness distribution of transparent plates is proposed by using the sampling moiré method. The thickness distribution is automatically analyzed by measuring the phase difference of the moiré fringe obtained from a single image, consistent with light refraction. The relationship between the actual thickness and phase difference of the moiré fringe is calibrated by using glass plates of known thicknesses. The thickness measured by the present method was found to be in agreement with measurements using a digital micrometer. In our experiment, the average error in glass plate thickness was 1.9% over a 3.5 mm measurement range. Experimental results indicate that the present method can be useful for nondestructive measurements of the thickness distribution of various transparent plates.

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Development of a noncontact optical sensor for measuring the shape of a surface and thickness of transparent objects

Cited by 18 publications

References 3 publications

Development and Beam-Shape Analysis of an Integrated Fiber-Optic Confocal Probe for High-Precision Central Thickness Measurement of Small-Radius Lenses

Development and Beam-Shape Analysis of an Integrated Fiber-Optic Confocal Probe for High-Precision Central Thickness Measurement of Small-Radius Lenses

Measurement method of optical properties by use of a rangefinder

A simple technique for measuring thickness distribution of transparent plates from a single image by using the sampling moiré method

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