G - Physics – 02 – B
Patent
G - Physics
02
B
88/105
G02B 11/30 (2006.01) G02B 13/24 (2006.01) G02B 21/02 (2006.01)
Patent
CA 1120298
ABSTRACT OF THE DISCLOSURE A reproducing objective lens for videodiscs for which the working distance is large, the flatness of field is high, resolving power is high and further, the objective lens is so corrected as to compensate for aberrations introduced by addi- tional elements fixed in the optical path and occurring in the long conjugate of the objective lens. For the objective lens, according to the present invention, the Gauss-type lens con- figuration is adopted as it is easier to obtain a large working distance and high flatness of field with the Gauss-type lens configuration. The objective lens for videodiscs, according to the present invention, is a modified Gauss-type lens system comprising five single lenses, i.e., a first, second, third, fourth and fifth lens. The first lens is a positive lens with its planar surface positioned toward the object side, the second lens is a positive lens, the third lens is a negative meniscus lens with its convex surface positioned toward the ob- ject side, the fourth lens is a negative meniscus lens with its concave surface positioned toward the object side and the fifth lens is a positive meniscus lens with its concave surface positioned toward the object side. Further, the objective lens for videodiscs of the present invention satisfies the following conditions when reference symbol f represents the focal length of the lens system as a whole. Reference symbol f3 represents the focal length of the third lens. Reference symbol f4 represents the focal length of the fourth lens. Reference symbol r6 represents the radius of curvature of the surface on the image side of the third lens. Reference symbol r7 re- presents the radius of curvature of the surface on the object side of the fourth lens. Reference symbol d represents the thickness of the first lens and reference symbol d5 represents the thickness of the third lens. 1. 0.30 .DELTA. r6/f ? 0.23 2. 0.25 ? d1/f ? 0.l5 3. 1.4 ? r6 ¦r7¦? 0.9 4. 6.0 ? f3¦/¦ f4 ? 2.5 5. 0.31 ? d5/f ? 0.21
343255
Gowling Lafleur Henderson Llp
Mca Discovision Inc.
LandOfFree
Reproducing objective lens for videodiscs does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Reproducing objective lens for videodiscs, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Reproducing objective lens for videodiscs will most certainly appreciate the feedback.
Profile ID: LFCA-PAI-O-97816