K9 Plano-Concave Lens

Overview

The Essential Negative Lens for Optical Design

The VenusLab PC-K9 Plano-Concave Series is engineered for applications requiring light divergence. In optical systems, they are typically placed in the beam path to expand spot diameter or combined with positive lenses to balance spherical aberration and extend system focal length.

Our K9 material undergoes precision annealing to ensure refractive index uniformity (n=1.519 @ 546.1nm), and combined with surface power accuracy of λ/4, guarantees wavefront integrity. Whether for laboratory beam expansion setups or industrial beam shaping, the PC-K9 Series delivers stable and reliable performance.

Key Applications

Beam Expanders:Used as the negative element in Galilean beam expanders (combined with a plano-convex lens).
Projection Systems: Diverging light beams for wide-area illumination.
Focal Length Extension : Increasing the effective focal length of an existing lens system.

Dimension:

Qualification

General Technical Specifications

Property	Specification
Material	K9 (Grade A Optical Glass)
Shape	Plano-Concave
Design Wavelength (λc)	546.1nm (n=1.519)
Surface Quality	40-20 Scratch-Dig
Surface Power (Fringes)	1-5
Irregularity (Fringes)	0.2-1
Clear Aperture	> 90%
Centration (General)	3' (Standard)
Chamfer	0.25mm x 45°
Diameter Tolerance	+0.0 / -0.1 mm
Thickness Tolerance	± 0.1 mm
Focal Length Tolerance	± 1%

Selection Chart

PC-K9 Series Model List

Model	D (mm)	f (mm)	Te (mm)	Tc (mm)	fb (mm)	r (mm)	Centration
VLPC-K9-06-06	6	-6	6	2	-7.3	3.114	≤ 1'
VLPC-K9-06-12	6	-12	4	2	-13.3	6.22	≤ 1'
VLPC-K9-10-15	10	-15	3.8	2	-16.3	7.79	≤ 1'
VLPC-K9-10-20	10	-20	3.3	2	-21.3	10.38	≤ 1'
VLPC-K9-10-30	10	-30	2.8	2	-31.3	15.57	≤ 1'
VLPC-K9-12-15	12.7	-15	5.3	2	-16.3	7.79	≤ 1'
VLPC-K9-12-25	12.7	-25.4	3.7	2	-26.7	13.18	≤ 1'
VLPC-K9-12-35	12.7	-35	3.2	2	-36.32	18.17	≤ 1'
VLPC-K9-12-38	12.7	-38	3.1	2	-39.4	19.72	≤ 1'
VLPC-K9-12-50	12.7	-50	2.8	2	-51.32	25.95	≤ 1'
VLPC-K9-12-400	12.7	-400	2.4	2	-401.3	207.6	≤ 1'
VLPC-K9-12-1K	12.7	-1000	2.2	2	-1001.4	519	≤ 1'
VLPC-K9-15-30	15	-30	3.9	2	-31.3	15.57	≤ 1'
VLPC-K9-20-25	20	-25	6.7	2	-26.3	12.98	≤ 1'
VLPC-K9-20-30	20	-30	5.6	2	-31.3	15.57	≤ 1'
VLPC-K9-20-40	20	-40	4.6	2	-41.3	20.76	≤ 1'
VLPC-K9-20-50	20	-50	4	2	-51.3	25.95	≤ 1'
VLPC-K9-20-80	20	-80	3.2	2	-81.3	41.52	≤ 1'
VLPC-K9-20-100	20	-100	3	2	-101.3	51.9	≤ 1'
VLPC-K9-20-150	20	-150	2.6	2	-151.3	77.85	≤ 1'
VLPC-K9-25-25	25	-25	11.16	2	-26.3	12.98	≤ 1'
VLPC-K9-25-35	25	-35	7	2	-36.3	18.17	≤ 1'
VLPC-K9-25-50	25	-50	5.2	2	-51.3	25.95	≤ 1'
VLPC-K9-25-75	25	-75	4.1	2	-76.3	38.93	≤ 1'
VLPC-K9-25-100	25	-100	3.5	2	-101.3	51.9	≤ 1'
VLPC-K9-25-200	25	-200	2.8	2	-201.3	103.8	≤ 1'
VLPC-K9-25-300	25	-300	2.57	2	-301.3	155.7	≤ 1'
VLPC-K9-25-500	25	-500	2.3	2	-501.3	259.5	≤ 1'
VLPC-K9-25A-35	25.4	-35	7	2	-36.3	18.17	≤ 1'
VLPC-K9-25A-50	25.4	-50	5.3	2	-51.3	25.95	≤ 1'
VLPC-K9-25A-75	25.4	-75	4.2	2	-76.3	38.93	≤ 1'
VLPC-K9-25A-100	25.4	-100	3.6	2	-101.3	51.9	≤ 1'
VLPC-K9-25A-150	25.4	-150	3	2	-151.3	77.85	≤ 1'
VLPC-K9-25A-200	25.4	-200	2.8	2	-201.3	103.8	≤ 1'
VLPC-K9-25A-300	25.4	-300	2.6	2	-301.3	155.7	≤ 1'
VLPC-K9-25A-400	25.4	-400	2.4	2	-401.3	207.6	≤ 1'
VLPC-K9-25A-800	25.4	-800	2.2	2	-801.3	415.2	≤ 1'
VLPC-K9-25A-1K	25.4	-1000	2.16	2	-1001.8	519	≤ 1'
VLPC-K9-25A-R2	25.4	-385	2.4	2	-386.3	200	≤ 1'
VLPC-K9-30-35	30	-35	9.9	2	-36.3	18.17	≤ 1'
VLPC-K9-30-50	30	-50	6.8	2	-51.3	25.95	≤ 1'
VLPC-K9-30-80	30	-80	4.8	2	-81.3	41.52	≤ 1'
VLPC-K9-30-100	30	-100	4.2	2	-101.3	51.9	≤ 1'
VLPC-K9-30-200	30	-200	3.1	2	-201.32	103.8	≤ 1'
VLPC-K9-50-75	50	-75	13.8	2	-76.3	38.93	≤ 1'
VLPC-K9-50-200	50	-200	6.1	2	-202	103.8	≤ 1'
VLPC-K9-50-100	50.8	-100	9.6	3	-101.4	51.9	≤ 1'