★Raw Material
About 250 types of high value glass for lens use. 100~200 times more expensive than ordinary glass. The lens is pressed to shape that closely matches the shape of the finishied product.
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★Grinding / Curve Generating
The surface of the blank lens is ground to generate the required radius
that is very close to the design redius and reduce thickness up to 0.01
mm of the design thickness using diamond grinding wheel.
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★Pellet Polishing
Lens undergoes this intermediate process after grinding and curve generating
to further reduce thickness and improve surface.
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★Pad Polishing
Lens from previous lapping process undergoes final polishing to make the
lens transparent. Depending on the pad polishing tool and polishing slurry
used, the accuracy of the lens curvature is further improve to about 0.0003
to 0.001 mm. This process requires high level of technological and operational
expertise.
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★Pitch Polishing
A number of lenses are attached to a base made of pitch and then polished
using polishing slurry, a mixture of water and polishing powder, at low
rpm to futher improve radius of lens and reduce the thickness to about
0.01 of the design value. Surface quality is very high because of the low
speed used in the process.
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★Inspection
Accuracy of curvature is checked by observing the light interference bands
called Newton Rings produced by a lens when placed in contact with a standard
Newton plate or test glass. Scratch and other polishing defects are visually
inspected against strong light.Scratch width is limited to 0.003〜0.006o.
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★Centering
The lens is machined for final diameter and accurate alignment of its optical
axis mechanical axis. This process is important for good image production.
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★Coating
To protect
lens, reduce its reflectivity and improve its transmissibility, a very thin
coating, about 14μ, is applied through vacuum deposition of magnesium fluoride.
Further protection is obtained through multiple coating.
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★Cementing
Depending on lens application, lenses of different materials are paired
and bonded. In pairing, it is very necessary that the optical axes of both
lenses be properly aligned.
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★Assembly
Finished lenses are assembled inside a frame or housing and alignment of
the optical axis of lens with the mechanical axis of the mounting is inspected
prior to delivery.
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★Plastic Lens Molding
This process uses high precision mold, fully automated injection machine,
high quality material dryer, and a clean room environment in order to produce
high quality plastic lenses. The process employs one hundred percent quality
control that is done through visual inspection and checking. Use of an
interferometer ensures high precision and constant level of product quality.
Materials used arecommonly PMMA and PS resins but are not necessarily restricted
to these.
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★Plastic Molding
Modern Injection Molding Machines are used to produce high precision molded
plastic products. These products are manufactured using short cycle times
in a fully air conditioned production room. Commonly used materials are
GPPS, PP, PC, SAN and ABS. Other materials may be used as required by design.
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