TWI326363B - Pickup image lens - Google Patents

Description

The 1326363 type positive lens 'and its imaging end surface is convex toward the imaging end; and the object end surface of the fourth lens is convex toward the imaging end. As described above, the pickup lens of the present invention must satisfy this condition: 0.1 < I - 1 < 1 f4 where 'F is the focal length value of the pickup lens, and f4 is the focal length value of the fourth lens. .

As described above, the first, third, and fourth lenses of the pickup lens of the present invention each have at least one aspherical surface. As described above, the aperture stop of the pickup lens of the present invention is located between the first lens and the second lens. As described above, the object end surface and the image forming end surface of the fourth lens of the present invention further satisfy this condition: 0.05 < RB - R7 Λ 8 + R7 < 0.8

Wherein R7 is the radius of curvature of the object end surface of the fourth lens, and R8 is the radius of curvature of the imaging end surface of the fourth lens. As described above, the object end surface of the second lens of the pickup lens of the present invention is convex toward the image forming end. An advantage of the present invention is that the use of a four-grain lens makes the pickup lens of the present invention have the advantages of a short length and a light weight. Preferably, the first positive lens, the second negative lens, the third positive lens, and the fourth lens are all made of a plastic material. Another advantage of the present invention is that the aperture lens is disposed between the first and sixth second lenses such that the image pickup lens has a wide viewing angle. The above and other technical contents, features and effects of the present invention will be apparent from the following detailed description of the preferred embodiments. The pickup lens of the present invention can be applied to an image manipulation device for imaging an object to an image sensing element such as a charge coupled device (CCD) or a complementary metal oxide semiconductor device (CMOS). The pickup lens sequentially includes a first lens having a positive refractive power, a second lens having a negative refractive power, a third lens having a positive refractive power, and a third having a weak refractive power from the object end to the money end. Four lenses. The aperture light is disposed between the first lens and the second lens. The first, third, and fourth lenses each have at least one aspherical surface. In the pickup lens of the present invention, the first lens is a crescent-shaped positive lens, and the object end surface thereof is convex toward the object end. The second lens is a negative lens whose object end surface is convex toward the imaging end. The third lens is a crescent-shaped positive lens, and its image end surface is convex toward the imaging end. The object end surface of the fourth lens is concave toward the imaging end, and its imaging end surface is convex toward the imaging end. In the present invention, the pickup lens must satisfy the following conditions: 01 < 1^1 < 1 (1) where 'F is the focal length value of the pickup lens, and f4 is the focal length value of the fourth lens. When 丨丨 is greater than the upper limit of condition (1), the total length of the pickup lens will be too long. When 丨F/f4| is smaller than the lower limit value of the condition (1), the distortion aberration 1326363 (distortion aberration) of the pickup lens is deteriorated to deteriorate the image quality. In addition, the object end surface and the imaging end surface of the fourth lens of the present invention further satisfy this condition: (2) °·05<Ι^<0·8 where R7 is the radius of curvature of the object end surface of the fourth lens And R8 is the radius of curvature of the imaging end surface of the fourth lens. When it is greater than the upper limit of the condition (2) R 〇 + R7 , the system aberration of the pickup lens is deteriorated to deteriorate the image quality. When it is less than the lower limit of the condition (2), the /?〇 + ΚΊ four lens will not be able to repair the aberration of the pickup lens. DETAILED DESCRIPTION OF THE INVENTION Referring to Fig. 1, in an embodiment of the pickup lens of the present invention, the pickup lens includes a first lens G1 having a positive refractive power and a first negative refractive power from an object end OBJ to an imaging end IMA. The second lens G2, the third lens G3 of positive refractive power, and the fourth lens G4 of weak refractive power; and the system focal length of the pickup lens are F=5.30 mm, and Fno.=2.86. Further, the aperture stop STO is located between the first lens G1 and the second lens G2. The first lens G1 is a crescent-shaped positive lens, and the first surface L1 and the second surface L2 are respectively included from the object end OBJ to the imaging end IMA, and the first surface L1 of the adjacent object end OBJ protrudes toward the object end OBJ. Further, the first surface L1 and the second surface L2 are both aspherical. The second lens G2 is a negative lens, and the third surface 8 1326363 L3 adjacent to the object end OBJ must protrude toward the imaging end IMA. Referring to Fig. 1, in this embodiment, the second lens G2 is a double concave lens, and the fourth surface L4 adjacent to the imaging end IMA is convex toward the object end OBJ. Further, the third surface L3 and the fourth surface L4 are both aspherical.

The third lens G3 is a crescent-shaped positive lens, and the fifth end surface L5 and the sixth surface L6 are respectively included from the object end OBJ to the imaging end IMA, and the sixth surface L6 adjacent to the imaging end IMA protrudes toward the imaging end IMA. Further, the fifth surface L5 and the sixth surface L6 are both aspherical. The fourth lens G4 is a crescent lens, and the self-object end OBJ to the imaging end IMA further includes a seventh surface L7 and an eighth surface L8, respectively, and an eighth surface L8 adjacent to the imaging end IMA protrudes toward the imaging end IMA. Further, the seventh surface L7 and the eighth surface L8 are both aspherical.

In the embodiment of the present invention, the parameters of the first, second, third, and fourth lenses of the image pickup lens are listed in Table 1:

Table 1 System focal length F = 5.30 mm ; Fno. = 2.86 Surface number Curvature radius (mm) Thickness (mm) Refractive index (Nd) Abbe's coefficient (Vd) L1 1.930 1.3000 1.524708 56.209669 L2 5.310 0.1260 1.000000 STO Infinity 0.0960 1.000000 L3 -7.050 0.4500 1.632205 23.000000 L4 17 0.2100 1.000000 L5 -11.030 1.2100 1.524708 56.209669 L6 -1.500 1.0700 1.000000 L7 -0.870 1.0100 1.632205 23.000000 L8 -1.350 0.6513811 1.000000 P1 Infinity 0.4000 BK7 BK7 P2 Infinity 0.5000 1.000000 IMA 9 1326363 Furthermore, an embodiment of the invention The first surface L1 and the second surface L2 of the first lens G1, the third surface L3 and the fourth surface L4 of the second lens G2, the fifth surface L5 and the sixth surface L6 of the third lens G3, and the fourth The seventh surface L7 and the eighth surface L8 of the lens G4 are aspherical, and the aspherical surface thereof

The relevant values are listed in Table 2: Table 2 Surface No. K E4 E6 E8 L1 0.48 -0.0050392926 0.0021913456 -0.0014250465 L2 2.38 -0.00083352449 -0.0013718912 0.040188674 L3 -21.04757 -0.053546679 0.013717798 0.033175 L4 69.82262 -0.024292605 0.046017405 0.04088452 L5 92 -0.056554037 0.056145764 - 0.042401596 L6 -0.4770624 0 -0.012896515 0.01564612 L7 -0.9245092 -0.037010503 0.073054406 -0.02508864 L8 -0.9410524 -0.011470449 0.0087493284 0.00013760692 Table 2 Surface No. E10 E12 E14 L1 0.00037960031 0.0002 L2 -0.018302779 -0.035079705 L3 -0.067300787 -0.016831451 L4. -0.099223281 0.03857995 L5 0.056375505 -0.035149063 L6 -0.019007507 0.010899159 -0.0021977762 L7 0.0014034024 0.00060022254 L8 -0.00056919011 0.000063340851 According to Table 1, it can be seen that the focal length f4 of the 4th lens G4 with weak refractive power is -20.963, which can be obtained as |F/f4|=0.253 and indeed meets Condition (1). According to Table 1, it is understood that the radius of curvature R7 of the seventh surface L7 of the fourth lens G4 is -0.87 mm, and the radius of curvature of the eighth surface L8 of the fourth through-wound G4 is R8 = -1.35 mm. Substituting R7 and R8 into R8-R7 R8 + R7 yields R8-R7 R8 + R7 10 1326363 0.216 and does qualify (2). Fig. 2 shows the spherical aberration of the pickup lens of the embodiment of the present invention. The spherical aberration is less than 0.07 mm in the range of 0.9283 mm. Fig. 3 shows a field curvature of a pickup lens according to an embodiment of the present invention. In the range of the image field height of 2.9 mm, the field aberration of the light of the meridional plane and the sagittal plane is less than 0.08 mm. Fig. 4 shows the distortion aberration of the pickup lens of the embodiment of the present invention. In the range of the image field height of 2.9 mm, the distortion of each wavelength of light is less than 0.15%. Fig. 5 shows ray aberrations (also referred to as ray fans) of the pickup lens of the embodiment of the present invention. When the image height is 0·0 mm, 1.8 mm, 2.3 mm, and 2.9 mm, the astigmatism of the pickup lens remains fairly flat. As apparent from the above, the pickup lens of the embodiment of the present invention has excellent image quality; although the first lens, the second lens, the third lens, and the fourth lens all use a plastic injection molded lens, they are not subject to temperature changes. And the imaging quality is deteriorated. Referring to Fig. 1 and Table 1, the aperture stop ST0 of the pickup lens of the present invention is located between the first lens G1 and the second lens G2. The above is only the specific embodiment of the present invention, and the scope of the present invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are all It is still within the scope of the invention patent. 11 1326363 BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows the position of a pickup lens of an embodiment of the present invention; FIG. 2 shows a spherical aberration of an image pickup lens according to an embodiment of the present invention; FIG. 3 shows an embodiment of the present invention. Fig. 4 shows the distortion aberration of the pickup lens of the embodiment of the present invention; Fig. 5 shows the ray aberration of the pickup lens of the embodiment of the present invention.

[Description of main component symbols] L1 First surface G1 * First lens L2 · · · Second surface G2 · ' · Second lens L3 · ' Third surface G3 · · Third lens L4 ... Fourth surface G4 .. Fourth lens L5 · 'Fifth surface IMA ' · Imaging end L6 · 'Sixth surface STO aperture stop L7 · · · Seventh surface OBJ * · Object L8 .. Eighth surface 0A ' * · Optical axis 12

Claims (1)

1326363 X. Patent application scope: Λ......... 1. A kind of pickup lens, including from the object end to the imaging end on the optical axis: the first lens is positive refractive power; a second lens having a negative refractive power; a third lens 'which is a positive refractive power; and a fourth lens having a weak refractive power, wherein the aperture mirror is disposed between the first lens and the second lens; the fourth lens A crescent lens has an object end surface and an image end surface, and both the object end surface and the image end surface are convex toward the imaging end; and the pickup lens satisfies the following condition: 0.1 &lt;丨&lt;1 ·' RS-R7 0.05&lt;0.8; where F is the focal length value of the pickup lens, and f4 is the focal length value of the fourth lens, and R7 is the radius of curvature of the object end surface of the fourth lens And R8 is the radius of curvature of the imaging end surface of the fourth lens. 2. The pickup lens according to claim </ RTI> wherein the first lens is a crescent-shaped positive lens having an object end surface and an image end surface, and the object end surface is convex toward the object end. 3. The pickup lens according to claim 2, wherein the third lens is a crescent-shaped positive lens having an object end surface and an image end surface, and an image end surface thereof is convex toward the image forming end. 4. According to the cleaning lens described in the third paragraph of the patent application, the fourth through 13 1326363 ί) ί 7 . , \ mirror is a crescent lens. 5. According to the scope of claim 4 A pickup lens, wherein the second lens has an object end surface and an image end surface, and an object end surface thereof protrudes toward the imaging end. 6. The first and third crescent-type positive lenses are made of a plastic material according to the image pickup lens described in the item 3-5 of the patent application. , 14