An optical lens

Abstract

The utility model discloses an optical lens relates to lens technical field. Optical lens includes the first lens with negative optical power, the second lens with negative optical power, the third lens with positive optical power, the fourth lens with positive optical power, the fifth lens with negative optical power, the sixth lens with positive optical power, the seventh lens with negative optical power and the eighth lens with positive optical power that have negative optical power in order along the optical axis from object side to image side. Adopt above-mentioned technical scheme, the optical power of each lens, position can be allocated reasonably, can realize the design of infrared confocal optical lens of big light -passing, big target surface, small volume, high image quality, can realize the aperture for 1.28 finally, and the total length of optics is not more than 22.5mm, and the imaging target surface can match the optical lens of 1 / 1.8 inch chip, satisfies the demand of definition imaging under extremely dark environment, can also satisfy the higher use demand in the field of security monitoring.

Claims

1. An optical lens, characterized in that, include: The following lenses are arranged sequentially along the optical axis from the object side to the image side: a first lens with negative optical power, a second lens with negative optical power, a third lens with positive optical power, a fourth lens with positive optical power, a fifth lens with negative optical power, a sixth lens with positive optical power, a seventh lens with negative optical power, and an eighth lens with positive optical power.

2. The optical lens according to claim 1, characterized in that, The object-side surface of the first lens is convex, and the image-side surface of the first lens is concave. The object-side surface of the second lens is concave, and the image-side surface of the second lens is convex. The object-side surface of the third lens is convex, and the image-side surface of the third lens is convex. The object-side surface of the fourth lens is convex, and the image-side surface of the fourth lens is convex. The object-side surface of the fifth lens is convex, and the image-side surface of the fifth lens is concave. The object-side surface of the sixth lens is convex, and the image-side surface of the sixth lens is convex. The object-side surface of the seventh lens is concave, and the image-side surface of the seventh lens is convex. The object-side surface of the eighth lens is convex.

3. The optical lens according to claim 1, characterized in that, The first lens, the second lens, the third lens, the seventh lens, and the eighth lens are all plastic aspherical lenses; The fourth lens, the fifth lens, and the sixth lens are all glass spherical lenses.

4. The optical lens according to claim 1, characterized in that, -1.20≤(Φ1+Φ2) / Φ≤-0.96; Φ1 is the optical power of the first lens; Φ2 is the optical power of the second lens; Φ is the overall optical power of the optical lens.

5. The optical lens according to claim 1, characterized in that, 1.001≤(Φ3+Φ4) / Φ≤1.17; Wherein, Φ3 is the optical power of the third lens; Φ4 is the optical power of the fourth lens.

6. The optical lens according to claim 1, characterized in that, The fifth lens is a convex-concave lens; the sixth lens is a biconvex positive power lens; the fifth lens and the sixth lens are bonded together with adhesive. Wherein, 0.16≤Φ56 / Φ≤0.27; -0.86≤Φ5 / Φ≤-0.19; 0.38≤Φ6 / Φ≤0.96; Φ56 is the optical power of the lens group formed by cementing the fifth lens and the sixth lens, Φ5 is the optical power of the fifth lens, and Φ6 is the optical power of the sixth lens.

7. The optical lens according to claim 1, characterized in that, -0.035≤(Φ7+Φ8) / Φ≤0.1; Wherein, Φ7 is the optical power of the seventh lens; Φ8 is the optical power of the eighth lens.

8. The optical lens according to claim 1, characterized in that, 1.43 <Nd4<1.66,53.6<Vd4<98; 1.59 <Nd5<2.01;16<Vd5<36.4; 1.43 <Nd6<1.63,54.0<Vd6<96.0; Wherein, Nd4 is the refractive index of the fourth lens, and Vd4 is the Abbe number of the fourth lens; Nd5 is the refractive index of the fifth lens, and Vd5 is the Abbe number of the fifth lens; Nd6 is the refractive index of the sixth lens, and Vd6 is the Abbe number of the sixth lens.

9. The optical lens according to claim 1, characterized in that, 0.77≤(BFL / TTL)*EPDI≤1.03; Wherein, BFL is the optical back focal length of the optical lens; TTL is the total length of the optical system of the optical lens; and EPDI is the entrance pupil diameter of the optical lens.

10. The optical lens according to claim 1, characterized in that, H / f≤0.98; Where H is the vertical height of the intersection point of the principal ray of the maximum field of view of the optical lens and the image plane; f is the focal length of the optical lens.

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