Optical Glass

preforms for precision molding lens

Preform for precision molding lens is optimized for molding aspherical lens or other special lenses. We provide the glass as gob or as polishing preforms.(polished ball or preform with approximate radius)

preforms for precision molding lens

gob preforms(non-polished preforms)

"The gob preform" is aggregated glass directly molded from furnace.
Use of the gob preform enables lens manufacturing that does not need grinding and polishing.

general specifications of precision gob preform

weight/pc 250~ 350mg 350~ 500mg 500~ 700mg 700~ 1000mg 1000~ 1200mg 1200~ 1500mg 1500mg〜
weight tolerance ± 5mg ± 5mg ± 5~10mg ± 10mg ± 10~15mg ± 15mg ± 20mg
shape biconvex, plano-convex, convex-concave
minimum quantity/lot 30,000pcs / lot consultation
  • ※ Please contact us about the minimum quantity/lot, separately.
  • ※ The weight tolerance may vary according to the glass type.
  • ※ Customized products within our specification is possible.

listing our glass type.(Gobs only)

Glass Type Catalogue Value After Molding※1 Tg At αx10-7 DW S.g Available form※2 Coloration※3
nd νd nd νd (°C) (°C)
K-PSFn202 2.01960 21.5 2.01365 21.5 460 486 86 1 6.22 (44)/40※6
K-PSFn2 2.00170 20.6 1.99670 20.6 480 514 92 1 5.48 (50)/40※6
K-PSFn1 1.90680 21.2 1.89948 21.4 498 543 102 1 4.15 (49)/39※6
K-VC99 1.85060 41.6 1.84604 41.5 616 653 73 1 5.15 42/32※6
K-PSFn3 1.83917 23.9 1.83352 24.0 477 515 118 1 3.90 (43)/38※6
K-VC89 1.81000 41.0 1.80589 40.9 528 559 83 1 4.75 40/34
K-VC100 1.80400 43.6 1.79916 43.5 570 609 72 1 4.71 40/34
K-VC82 1.75550 45.6 1.75029 45.4 526 563 80 1 4.25 38/33
K-CD120 1.72250 29.2 1.71468 29.6 508 549 119 1 3.01 43/36
K-ZnSF8 1.71430 38.9 1.71142 38.9 518 546 60 2 3.72 39/34
K-VC80 1.69384 53.1 1.68984 52.8 530 566 94 1 3.81 36/29
K-CD45 1.69320 33.7 1.68673 34.1 470 507 121 1 3.13 41/35
K-VC78 1.66955 55.4 1.66625 55.2 520 556 100 1 3.44 35/28
K-PG395 1.65800 36.9 1.65295 36.8 363 392 159※5 1 3.50 38/35
K-PSK200 1.61305 59.0 1.61083 58.9 386 412 123 1 3.38 34/31
K-VC79 1.61035 57.9 1.60736 57.5 516 553 93 2 3.09 34/29
K-PSK300 1.59950 65.6 ※7 ※7 463 498 128 2 3.49 36/31
K-PSK100 1.59170 60.7 1.58793 60.5 390 415 114 1 3.24 36/32
K-CSK120 1.58700 59.6 1.58444 59.2 498 536 91 2 3.00 35/31
K-PG375 1.54250 62.9 1.53921 62.5 344 367 160※5 2 2.90 36/31
K-PBK50 1.52250 62.3 1.52023 62.0 481 518 92 2 2.43 34/29
  • ※1:Reference value after molding by SUMITA
  • ※2:Available form:○ Gobs or Polished Preform △ Polished Preform
  • ※3:Transmittance wavelength at 80%/5%
  • ※4:Value (50〜200℃)
  • ※5:Value (50〜250℃)
  • ※6:Transmittance wavelength at 70%/5%
  • ※7:The data is being measured now

polishing preforms

"For such optical glass that gob preform is difficult to be manufactured, it is general to apply polished "ball" or "preform with approximate radius".
Sumita's polished preforms are available for a wide range of applications covering from small production to mass production as stable preforms for precision molding lenses.

specifications for polishing preforms

shape balls approximate radius
Dimensions (mm) φ1.2〜20 consultation
ball sphericity (mm) less than φ ± 0.005
surface finish mirror polishing
  • ※ For other specifications, please contact us separately.
  • ※ Concerning K-PSFn1 and K-PSFn3, please consult us in advance, since solarization may occur according to the conditions of application in.
  • ※ Customized products within our specification is possible.

listing our glass type.

Glass Type Catalogue Value After Molding※1 Tg At αx10-7 DW S.g Available form※2 Coloration※3
nd νd nd νd (°C) (°C)
K-PSFn214 2.14355 17.8 2.13909 17.7 425 449 98 1 7.06 (48)/42※6
K-PSFn202 2.01960 21.5 2.01365 21.5 460 486 86 1 6.22 (44)/40※6
K-PSFn2 2.00170 20.6 1.99670 20.6 480 514 92 1 5.48 (50)/40※6
K-PSFn1 1.90680 21.2 1.89948 21.4 498 543 102 1 4.15 (49)/39※6
K-VC91 1.88660 35.0 1.88176 34.9 589 638 95 1 4.87 48/36※6
K-VC90 1.85280 39.0 1.84859 38.9 583 633 94 1 4.98 45/34※6
K-VC99 1.85060 41.6 1.84604 41.5 616 653 73 1 5.15 42/32※6
K-PSFn3 1.83917 23.9 1.83352 24.0 477 515 118 1 3.90 (43)/38※6
K-VC89 1.81000 41.0 1.80589 40.9 528 559 83 1 4.75 40/34
K-VC100 1.80400 43.6 1.79916 43.5 570 609 72 1 4.71 40/34
K-LaFK50 1.77200 50.0 1.76831 49.6 560 592 90 1 5.20 37/29
K-LaFK50T 1.76600 49.8 ※7 ※7 576 612 81 1 4.75 37/30
K-VC82 1.75550 45.6 1.75029 45.4 526 563 80 1 4.25 38/33
K-CD120 1.72250 29.2 1.71468 29.6 508 549 119 1 3.01 43/36
K-ZnSF8 1.71430 38.9 1.71142 38.9 518 546 60 2 3.72 39/34
K-LaFK58 1.69560 59.0 ※7 ※7 542 577 93 1 4.56 36/28
K-LaFK55 1.69400 56.3 1.68874 55.7 514 556 91 1 4.34 37/29
K-VC80 1.69384 53.1 1.68984 52.8 530 566 94 1 3.81 36/29
K-CD45 1.69320 33.7 1.68673 34.1 470 507 121 1 3.13 41/35
K-VC78 1.66955 55.4 1.66625 55.2 520 556 100 1 3.44 35/28
K-PG395 1.65800 36.9 1.65295 36.8 363 392 159※5 1 3.50 38/35
K-LaFK60 1.63246 63.8 1.62847 63.2 485 528 114 1 4.29 38/28
K-PSK200 1.61305 59.0 1.61083 58.9 386 412 123 1 3.38 34/31
K-VC79 1.61035 57.9 1.60736 57.5 516 553 93 2 3.09 34/29
K-PSK300 1.59950 65.6 ※7 ※7 463 498 128 2 3.49 36/31
K-GFK68 1.59240 68.3 1.58999 68.1 512 536 152 1 4.51 34/28
K-PSK100 1.59170 60.7 1.58793 60.5 390 415 114 1 3.24 36/32
K-CSK120 1.58700 59.6 1.58444 59.2 498 536 91 2 3.00 35/31
K-GFK70 1.56907 71.3 1.56626 71.2 485 509 156 1 4.46 34/28
K-PG375 1.54250 62.9 1.53921 62.5 344 367 160※5 2 2.90 36/31
K-PMK30 1.52500 70.4 1.52003 69.9 528 572 87 2 2.60 33/29
K-PBK50 1.52250 62.3 1.52023 62.0 481 518 92 2 2.43 34/29
K-PBK40 1.51760 63.5 1.51497 63.4 501 549 73 2 2.39 33/29
K-PG325 1.50670 70.5 1.50506 70.3 288 317 165※4 1 3.00 34/30
K-PFK80 1.49700 81.5 1.49533 80.9 461 483 154 1 3.60 34/27
K-PFK85 1.48563 85.2 1.48375 85.0 452 484 163 1 3.97 34/29
K-PFK90 1.45880 90.0 1.45744 87.6 431 461 165 1 3.72 34/29
K-CaFK95 1.43425 95.0 1.43312 95.0 431 450 167 1 3.54 33/28
  • ※1:Reference value after molding by SUMITA
  • ※2:Available form:○ Gobs or Polished Preform △ Polished Preform
  • ※3:Transmittance wavelength at 80%/5%
  • ※4:Value (50〜200℃)
  • ※5:Value (50〜250℃)
  • ※6:Transmittance wavelength at 70%/5%
  • ※7:The data is being measured now
Contact us for information and questions
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