Imaging lens

Abstract

To obtain a high-performance imaging lens coping with a larger number of pixels. The imaging lens includes a first positive lens G1 whose surface on an object side is convex, a second lens G2 which is a negative meniscus turning its concave surface to an image surface side, a third lens G3 which is a positive meniscus turning its convex surface to the image surface side, a fourth negative lens G4 whose both surfaces are aspherical and whose surface on the image surface side is concave near an optical axis, and a fifth positive or negative lens G5 whose both surfaces are aspherical in order from the object side. The imaging lens satisfies following conditions; (1) [nu]d1>50, (2) [nu]d2<30 and (3) [nu]d4<30 concerning the Abbe numbers of the first and the second lenses G1 and G2 are [nu]d1 and [nu]d2, and the Abbe number of the fourth lens G4 is [nu]d4.

Description

technical field [0001] The present invention relates to an imaging lens mounted on a video camera using an imaging element such as a CCD (Charged Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor). Background technique [0002] Imaging elements such as CCDs and CMOSs ​​have been progressing towards very small size and high pixel count in recent years. For this reason, the camera body and the lens mounted thereon are also required to be compact and high performance. In addition, in order to correspond to a high-pixel imaging element, telecenter is required, that is, the incident angle of the chief ray to the imaging element is approximately parallel to the optical axis (the incident angle on the imaging surface is approximately parallel to the normal line of the imaging surface). to zero). Conventionally, for example, many imaging lenses mounted on a mobile phone with a video camera consist of three lenses. However, the number of lenses tends to increase fu...

AI Technical Summary

Problems solved by technology

[0004] However, the imaging lens described in Patent Document 1 has room for improvement in terms of chromatic aberration and the like.

In addition, in the imaging lens, in order to ensure the telecentricity, it is considered that the aperture stop is arranged on the object side as much as possible, but in this case, as in the imaging lens described in Patent Document 1, the object side of the second lens If the surface is concave, the manufacturing sensitivity is high. For example, if there is a misalignment of the lens during manufacturing, it is easy to cause image plane fluctuations

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