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CN-118838031-B - Projection lens

CN118838031BCN 118838031 BCN118838031 BCN 118838031BCN-118838031-B

Abstract

The invention provides a projection lens, which sequentially comprises a first lens with positive focal power, a second lens with negative focal power, a third lens with focal power, a fourth lens with negative focal power, a fifth lens with positive focal power, a sixth lens with positive focal power and a convex image source side surface from a projection surface to an image source surface, wherein the effective focal length f of the projection lens and the curvature radius R12 of the image source side surface of the sixth lens meet the requirement that R12/f < -1 > are satisfied. The invention improves the imaging quality of the projection lens, reduces the aberration and improves the projection quality of the projection lens through reasonable configuration of the surface type of each lens and reasonable collocation of the focal power.

Inventors

  • Liang Liufeng
  • BAO YUMIN

Assignees

  • 江西联创电子有限公司

Dates

Publication Date
20260512
Application Date
20240808

Claims (10)

  1. 1. A projection lens comprising six lenses, in order from a projection surface to an image source surface along an optical axis, comprising: a first lens having positive optical power, the projection side surface and the image source side surface of which are both convex; a second lens having negative optical power, the image source side surface of which is concave; A third lens having optical power; a fourth lens having negative optical power, the image source side surface of which is concave; A fifth lens having positive optical power, the projection side surface and the image source side surface of which are both convex; a sixth lens having positive optical power, the image source side surface of which is convex; The effective focal length f of the projection lens and the curvature radius R12 of the image source side surface of the sixth lens meet the conditions that R12/f < -1 > is less than or equal to-3.29; The effective focal length f of the projection lens and the maximum field angle FOV and the real image height IH corresponding to the maximum field angle satisfy 0.95< (IH/2)/(f×tan (FOV/2)) <1.
  2. 2. The projection lens according to claim 1, wherein the chief ray incidence angle CRA at the maximum image height of the projection lens satisfies 1.89 ° -CRA <2.1 °, and the third lens is a meniscus lens.
  3. 3. The projection lens according to claim 1, wherein an effective focal length f of the projection lens and an image source side surface radius of curvature R12 of the sixth lens satisfy-3.29≤R12/f≤1.24; the effective focal length f of the projection lens and the maximum field angle FOV and the real image height IH corresponding to the maximum field angle are met, wherein (IH/2)/(f multiplied by tan (FOV/2)) is less than or equal to 0.96 and less than or equal to 0.98.
  4. 4. The projection lens of claim 1, wherein an effective focal length f of the projection lens and a back focal length BFL of the projection lens satisfy 1.8< BFL/f <2.5.
  5. 5. The projection lens of claim 1, wherein the effective focal length f of the projection lens and the focal length f1 of the first lens satisfy 1.4< f1/f <4.4.
  6. 6. The projection lens of claim 1, wherein the effective focal length f of the projection lens and the focal length f2 of the second lens satisfy-1.6 < f2/f < -0.5, and the effective focal length f of the projection lens and the focal length f6 of the sixth lens satisfy-1.4 < f6/f <2.9.
  7. 7. The projection lens of claim 1, wherein the effective focal length f of the projection lens and the image source side surface radius of curvature R2 of the first lens satisfy R2/f < -5.5.
  8. 8. The projection lens according to claim 1, wherein an effective focal length f of the projection lens and a projection side surface curvature radius R9 of the fifth lens satisfy 0.8< R9/f <3.2.
  9. 9. The projection lens of claim 1, wherein the radius of curvature R9 of the projection side surface of the fifth lens and the radius of curvature R10 of the image source side surface of the fifth lens satisfy R9/R10< -0.5 being-1.84.
  10. 10. The projection lens of claim 1, wherein the projection side surface light-transmitting half aperture d9 of the fifth lens and the projection side surface light-transmitting half aperture sagittal height Sag9 of the fifth lens satisfy 0.1< Sag9/d9<0.5, and the image source side surface light-transmitting half aperture d12 of the sixth lens and the image source side surface light-transmitting half aperture sagittal height Sag12 of the sixth lens satisfy-0.6 < Sag12/d12< -0.1.

Description

Projection lens Technical Field The present disclosure relates to imaging lenses, and particularly to a projection lens. Background Along with the continuous improvement of the requirements of people on driving experience, the use of the vehicle-mounted application projection lens in intelligent driving is more and more, and the position of the vehicle-mounted projection lens in the related industries of automobiles is continuously improved. The Head up Display system (HUD) is also called an automobile Head up Display system, which displays automobile driving auxiliary information, navigation information, inspection control information, ADAS information and the like on a windshield glass or in front of about 2m far and above the tip of an engine cover in a projection mode by utilizing an optical reflection principle, and can Display warning information from each driving auxiliary system, such as lane departure warning, pedestrian avoidance warning from a night vision auxiliary system with a pedestrian recognition function and the like, so that a driver is prevented from frequently looking down at an instrument or a vehicle-mounted screen in the driving process, and a good auxiliary effect is achieved on driving safety. However, the projection lens for the vehicle-mounted HUD in the market has the defects that the projected pattern is easy to generate dark angle, the brightness of the projection surface is insufficient, the pattern is unclear, and the like, so that the use requirement is difficult to meet. Disclosure of Invention In view of the foregoing, an object of the present invention is to provide a projection lens with high imaging quality. The invention provides a projection lens, which comprises six lenses in sequence from a projection surface to an image source surface along an optical axis: a first lens having positive optical power, the projection side surface and the image source side surface of which are both convex; a second lens having negative optical power, the image source side surface of which is concave; A third lens having optical power; a fourth lens having negative optical power, the image source side surface of which is concave; A fifth lens having positive optical power, the projection side surface and the image source side surface of which are both convex; a sixth lens having positive optical power, the image source side surface of which is convex; wherein the effective focal length f of the projection lens and the curvature radius R12 of the image source side surface of the sixth lens meet R12/f < -1. Further preferably, the incidence angle CRA of the chief ray at the maximum image height of the projection lens satisfies CRA <2.1 DEG, and the third lens is a meniscus lens. Further preferably, the effective focal length f of the projection lens satisfies 0.95< (IH/2)/(f×tan (FOV/2)) <1 with respect to the maximum field angle FOV and the real image height IH corresponding to the maximum field angle. Further preferably, the effective focal length f of the projection lens and the back focal length BFL of the projection lens satisfy BFL/f >1.8. Further preferably, the effective focal length f of the projection lens and the focal length f1 of the first lens satisfy 1.4< f1/f <4.4. Further preferably, the effective focal length f of the projection lens and the focal length f2 of the second lens meet-1.6 < f2/f < -0.5, and the effective focal length f of the projection lens and the focal length f6 of the sixth lens meet-1.4 < f6/f <2.9. Further preferably, the effective focal length f of the projection lens and the image source side surface curvature radius R2 of the first lens satisfy R2/f < -5.5. Further preferably, the effective focal length f of the projection lens and the projection side surface radius of curvature R9 of the fifth lens satisfy 0.8< R9/f <3.2. Further preferably, the radius of curvature R9 of the projection side surface of the fifth lens and the radius of curvature R10 of the image source side surface of the fifth lens satisfy R9/R10< -0.5. Further preferably, the projection side surface light-transmitting half aperture d9 of the fifth lens and the projection side surface light-transmitting half aperture Sag9 of the fifth lens satisfy that 0.1< Sag9/d9<0.5, and the image source side surface light-transmitting half aperture d12 of the sixth lens and the image source side surface light-transmitting half aperture Sag12 of the sixth lens satisfy that-0.6 < Sag12/d12< -0.1. The projection lens provided by the invention improves the imaging quality of the projection lens, reduces the aberration and improves the projection quality of the projection lens through reasonable configuration of the lens surfaces and reasonable collocation of the optical power, so that the lens has one or more advantages of small distortion, large aperture, large image surface, high imaging quality and the like. Drawings The foregoing and/or additional aspects and advantages of the invention will b