TWI394997B - Miniature camera lens - Google Patents

Description

Miniature imaging lens

The invention relates to an image taking lens, in particular to a high-performance, low-cost and short-sized miniature image taking lens suitable for use in a thin digital image product.

The integration of digital imaging products and optoelectronic technology has become one of the trends in the development of today's technology. In order to meet the requirements of portability, light, thin, short and small have become the basic needs of digital imaging products. In the lens shape and material selection of the image capturing lens used in the digital image product, since the material selection of the conventional spherical grinding glass lens is large, it is advantageous for correcting the chromatic aberration, and thus has been widely used in the industry. However, when the spherical grinding glass lens is used in a case where the numerical aperture (F Number) is small and the viewing angle (Wide-angle) is large, correction of aberrations such as spherical aberration and astigmatism is still difficult. In order to effectively correct the aberrations, the conventional image taking lens is usually composed of a plurality of lens groups, such as the image taking lens structure disclosed in U.S. Patent No. 6,031,670. However, such an image taking lens composed of a multi-lens group has a relatively long overall size, and requires a large installation space, and is not suitable for a thin digital image product such as a mobile phone or a digital camera having a thickness of 20 mm or less. The lens is difficult to fit into digital imaging products, and the cost is increased due to excessive lenses and the weight of the final product is increased.

The appearance of the aspherical lens solves the above problem. Applying it to the optical system of the lens can greatly improve the imaging quality and reduce the barrel deformation of the wide-angle lens, and an aspherical lens can replace the several spherical lenses to compensate for the aberration. Significantly simplifies the optical design of the lens, reducing its size and weight. The aspherical lens can be classified into an aspherical plastic lens, an aspherical glass lens, and an aspheric composite lens depending on the material. Production of aspherical glass lens Forming the method for precision grinding and molding. Among them, the precision grinding method needs to undergo aspherical grinding and polishing process, the mass production is relatively low and the technical threshold is high, and the manpower, raw materials and equipment required for the glass mold forming method (GMP, Glass Molding Press) are high, so It is greatly limited when used in thin digital imaging products with cost requirements. The aspherical composite lens (HBL, Hybrid Lens) is formed by laminating a layer of aspherical resin on the polished glass spherical lens, so that the manufacturing cost is high and the temperature is not high. Non-spherical plastic lenses can be fabricated by precision turning or injection molding. In comparison, they are easy to process and cost less. Therefore, aspherical plastic lenses are used in the industry as optical components for small imaging lenses to shorten the entire optical system. System and reduce costs.

Recently, with the rapid development of thin digital image products such as digital cameras, the design has become increasingly thin and short, and the cost has been decreasing. At the same time, image sensing components such as CCDs in digital imaging products have also become high pixels. For the above reasons and to overcome optical aberrations, the design of the miniature image taking lens tends to be strict. Therefore, how to design a miniature image-taking lens suitable for thin digital image products such as digital cameras, which has the advantages of short size, simple structure, easy processing, low cost, good image quality and high pixel demand. Advantages have become a common aspiration in the industry.

It is an object of the present invention to provide a miniature image taking lens which has the characteristics of short size, simple structure, easy processing, low cost, and good image quality to meet high pixel requirements.

A miniature image taking lens provided for the purpose of the present invention can be applied to a thin digital image A product, such as a digital camera, includes a first lens group having a negative refracting power, an aperture stop, and a second lens group having a positive refracting power, wherein the first lens group is sequentially along the optical axis from the object side to the image side. Consisting of a first lens having a negative refracting power, the second lens group sequentially follows a second lens having a positive refracting power, a third lens having a positive refracting power, and a negative refracting power from the object side to the image side along the optical axis. a fourth lens composition; the miniature image taking lens includes at least three aspherical lenses and satisfies -0.5 < (2Gf / 1Gf) < 0, wherein 1Gf is the focal length of the first lens group, and 2Gf is the focal length of the second lens group .

The miniature image taking lens of the present invention more satisfies -4.5 < (L1f / L2f) < - 2, where L1f is the focal length of the first lens, and L2f is the focal length of the second lens.

The miniature image taking lens of the present invention is more satisfying to -1.5 < (L3f / L4f) < - 0.5, wherein L3f is the focal length of the third lens, and L4f is the focal length of the fourth lens.

According to a preferred embodiment of the present invention, the first lens, the second lens and the fourth lens are all aspherical lenses.

According to a preferred embodiment of the present invention, the first lens of the first lens group is a crescent-type negative lens having a concave surface facing the object side and a convex surface facing the image side. The first lens is a plastic aspherical lens, and the concave surface and the convex surface are aspherical surfaces.

According to a preferred embodiment of the present invention, the second lens of the second lens group is a crescent-shaped positive lens having a concave surface facing the object side and a convex surface facing the image side, the third lens being a pair A convex positive lens, the fourth lens being a double concave negative lens. Wherein, the second lens is a plastic aspherical lens, and the concave surface and the convex surface are aspherical surfaces; the fourth lens is also a plastic aspherical lens, and the image surface is an aspherical surface; the third lens is a glass Spherical The lens or a plastic aspherical lens, when the third lens is a plastic aspherical lens, comprises at least one aspherical surface.

According to a preferred embodiment of the present invention, the third lens and the fourth lens of the second lens group are glued together.

According to a preferred embodiment of the present invention, a glass plate is further disposed between the second lens group and the imaging surface.

Compared with the prior art, the miniature image taking lens of the present invention has only a negative and a positive lens group, that is, four lenses, and has the advantages of short size, simple structure, and convenient assembly; by using at least three aspherical lenses and components The lens refractive index configuration can effectively correct various aberrations and chromatic aberrations, improve resolution and meet high pixel requirements; replace multiple traditional spherical glass lenses or aspherical glass lenses with multiple aspherical plastic lenses. Or aspheric composite lenses, which can greatly reduce the cost, and can easily correct aberrations, shorten the optical length of the lens, and improve production yield. In addition, the third and fourth lenses are glued together to avoid unnecessary tolerances, which makes the lens of the present invention easier to process and further reduces the cost.

The miniature image taking lens of the present invention can be applied to a thin digital image product such as a digital camera for imaging a target image to an image sensing element such as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS).

The foregoing and other objects, features, and advantages of the invention will be apparent from For the sake of brevity, the same elements are denoted by the same reference numerals in the various embodiments.

First embodiment

Referring to the first embodiment of the miniature image taking lens of the present invention shown in the first figure, the miniature image capturing lens of the present invention is from the object side (one side indicated by OBJ in the figure) to the image side (one of the IMA marks in the figure) The side side includes, along the optical axis OA, a first lens group G1 having a negative refracting power, an aperture stop ST, a second lens group G2 having a positive refracting power, a glass plate GP, and an imaging surface IP.

The first lens group G1 is composed of a first lens L1 having a negative refracting power, and the first lens L1 is a crescent-shaped negative lens having a concave surface S1 facing the object side and a convex surface S2 facing the image side. The first lens L1 is an aspherical lens made of plastic, and both the concave surface S1 and the convex surface S2 are aspherical.

The second lens group G2 includes, in order from the object side to the image side along the optical axis OA, a second lens L2 having positive refractive power, a third lens L3 having positive refractive power, and a fourth lens L4 having negative refractive power. The second lens L2 is a crescent-shaped positive lens having a concave surface S4 facing the object side and a convex surface S5 facing the image side. The third lens L3 is a double convex positive lens having two convex surfaces S6 and S7. The fourth lens L4 is a double concave negative lens having two concave surfaces S7 and S8. In the present embodiment, the third lens L3 and the fourth lens L4 are glued together to each other, whereby the aberrations can be effectively corrected by the combination of the two lenses, one convex and one concave. In the production material, the second lens L2 and the fourth lens L4 are made of plastic, and the third lens L3 is made of glass. In the aspherical configuration, preferably, the concave surface S4 and the convex surface S5 of the second lens L2 are aspherical, and the image surface S8 of the fourth lens L4 is also an aspherical surface.

As described above, the first lens L1 is a concave lens having a negative refractive power, and the second lens L2 As a convex lens having a positive refractive power, the two are respectively disposed on both sides of the aperture stop ST, and the mutual cooperation can effectively correct the chromatic aberration. By providing both the first lens L1 and the second lens L2 as aspherical lenses, the aberration can be corrected to improve the resolution.

The glass plate GP is disposed between the second lens group G2 and the image plane IP, which may be a member capable of providing a proper function, for example, a suitable optical coating may be applied on the surfaces S9 and S10 to provide a desired optical property. It can also be any suitable function or construction that is well known to those skilled in the art.

The tolerance distribution of the first lens group G1 and the second lens group G2 of the present invention is evenly distributed, and the production yield of the micro imaging lens of the present invention can be greatly improved.

The miniature image taking lens of the first embodiment of the present invention satisfies the following conditional expression (1): -0.5 < (2Gf / 1Gf) < 0 (1)

Here, 1Gf is the focal length of the first lens group G1, and 2Gf is the focal length of the second lens group G2.

The miniature image taking lens of the first embodiment of the present invention further satisfies the following conditional expression (2): -4.5 < (L1f / L2f) < - 4 (2)

Here, L1f is the focal length of the first lens L1, and L2f is the focal length of the second lens L2.

The miniature image taking lens of the first embodiment of the present invention satisfies the following conditional expression (3): -1.5 < (L3f / L4f) < - 0.5 (3)

Here, L3f is the focal length of the third lens L3, and L4f is the focal length of the fourth lens L4.

According to the conditions of the above first embodiment, the first numerical embodiment of the micro imaging lens of the present invention will be described in detail below. In the first numerical embodiment shown in Tables 1 and 2 and the numerical examples described below, the radius of curvature and the distance/thickness value are in millimeters (mm). In addition, Table 1 The two columns "type" and "curvature radius" refer to the type of the corresponding lens surface (ie whether it is "aspherical" or "standard" type surface) and its radius of curvature; the "distance/thickness" column is Refers to the thickness measured by each lens along the optical axis OA, or the distance between two adjacent elements along the optical axis OA, such as the image side surface (surface S5) of the previous lens (such as the second lens L2) and the latter The distance between the object surface (surface S6) of the lens (such as the third lens L3) along the optical axis OA; the column of "material" refers to the material of each lens L1 to L4 and the glass plate GP; "aspherical parameters" The column refers to the parameter Conic of the aspherical surface of each lens.

As shown in Table 1, in the first embodiment, both surfaces S1 and S2 of the first lens L1, the two surfaces S4 and S5 of the second lens L2, and the image surface S8 of the fourth lens L4 are aspherical. Some aspheric design formulas are expressed as follows:

Where: z is the displacement value of the surface apex as the reference distance from the optical axis along the optical axis direction; k is the taper constant (Conic Constant); c=1/r, r is the radius of curvature; h is the lens height A represents four aspherical coefficients (4th Order Aspheric Coefficient); B represents six aspherical coefficients; C represents eight aspherical coefficients; D represents ten aspherical coefficients; and E represents twelve non-spherical coefficients; Spherical coefficient; F represents fourteen aspheric coefficients; G represents sixteen aspheric coefficients.

In the first embodiment, the specific values of the aspheric coefficients are: Surface number S1 (object-side surface of the first lens L1): A=0.016216529 B=0.00069809517 C=4.9084973e-005 D=0.000176196 E=-0.00054887983 F=0.00028821148 G=-4.8640658e-005

Surface number S2 (image side surface of the first lens L1): A=0.014085077 B=0.0073518457 C=-0.0140479 D=0.012392953 E=0.0014480977 F=-0.010521447 G=0.0043430415

Surface number S4 (object-side surface of the second lens L2): A=-0.0090528106 B=-0.022641676 C=0.034316925 D=-0.044037015 E=0.0057647445 F=0.020371297 G=-0.011650563

Surface number S5 (image side surface of the second lens L2): A=-0.00029088056 B=-0.00075969358 C=0.0011149694 D=-0.00061092153 E=0.00018238334 F=-2.5981683e-005 G=1.6007994e-006

Surface number S8 (image side surface of the fourth lens L4): A=0.0024996357 B=-0.00045958532 C=-0.00012389176 D=9.6362954e-006 E=2.2009957e-005 F=-8.0792764e-006 G=8.2836645e-007

According to the first embodiment described above and the first numerical embodiment thereof, as shown in the second, third, fourth to fourth F and fifth figures, respectively, the miniature of the first embodiment of the present invention The image lens has a good correction effect on field curvature, distortion aberration, comet aberration and longitudinal spherical aberration, and can meet the demand of high pixels. In addition, the sixth figure shows an MTF (Modulation Transfer Function) modulation transfer function characteristic curve, which shows that the miniature image taking lens of the first embodiment of the present invention has good contrast characteristics and resolution performance. The seventh figure shows a one-phase contrast (refers to the percentage of the central illumination of the screen and the peripheral illumination), which shows that the miniature imaging lens of the first embodiment of the present invention has good light transmission efficiency.

Second embodiment

Referring to the second embodiment of the miniature image taking lens of the present invention shown in FIG. 8 , which is structurally different from the first embodiment shown in the first figure in that the third lens of the second lens group G2 L3 and the fourth lens L4 are mutually independent lenses, and the first to fourth lenses L1 to L4 are all aspherical lenses made of plastic. In the second embodiment, preferably, both surfaces of each of the first, second, and third lenses L1, L2, and L3 are aspherical, and the image-side surface S9 of the fourth lens L4 is also aspherical.

The miniature image taking lens of the second embodiment of the present invention satisfies the following conditional expression (1): -0.5 < (2Gf / 1Gf) < 0 (1)

Here, 1Gf is the focal length of the first lens group G1, and 2Gf is the focal length of the second lens group G2.

The miniature image taking lens of the second embodiment of the present invention further satisfies the following conditional expression (4): -3 < (L1f / L2f) < - 2 (4)

Here, L1f is the focal length of the first lens L1, and L2f is the focal length of the second lens L2.

The miniature image taking lens of the second embodiment of the present invention satisfies the following conditional expression (3): -1.5 < (L3f / L4f) < - 0.5 (3)

Here, L3f is the focal length of the third lens L3, and L4f is the focal length of the fourth lens L4.

In accordance with the conditions of the second embodiment above, the relevant numerical values of the second numerical embodiment of the micro imaging lens of the present invention will be listed in detail below, as shown in Tables 3 and 4.

As shown in Table 3, in the second embodiment, both surfaces S1 and S2 of the first lens L1, both surfaces S4 and S5 of the second lens L2, and both surfaces S6 and S7 of the third lens L3 and the fourth lens L4 are shown. The image surface S9 is aspherical.

In the second embodiment, the specific values of the aspherical coefficients are: Surface number S1 (object-side surface of the first lens L1): A=0.013114762 B=0.0063792957 C=-0.007025758 D=0.0041449169 E=-0.0014934894 F=0.00033329354 G=-3.7465436e-005

Surface number S2 (image side surface of the first lens L1): A=-0.027216598 B=0.033666296 C=-0.007711144 D=-0.011418147 E=0.0062444734 F=0.0018589121 G=-0.0013222171

Surface number S4 (object-side surface of the second lens L2): A=0.0053282954 B=-0.051228129 C=0.082795241 D=-0.070753612 E=0.012582494 F=0.01586379 G=-0.007442531

Surface number S5 (image side surface of the second lens L2): A=0.0025630078 B=-0.0020559344 C=0.0027263808 D=-0.00149524 E=0.00037260802 F=-2.2936181e-005 G=-4.832126e-006

Surface number S6 (object-side surface of the third lens L3): A=-0.00018375321 B=0.0012571401 C=-5.2397887e-005 D=-1.0515669e-005 E=3.1781937e-006 F=-8.887507e-009 G= -1.1434298e-008

Surface number S7 (image side surface of the third lens L3): A=0.0017145826 B=0.0016583387 C=0.00011294023 D=-4.1353991e-006 E=-1.0062774e-006 F=-4.8802445e-007 G=-1.2590963e- 008

Surface number S9 (image surface of the fourth lens L4): A = 0.0015197167 B = -0.00018631148 C = -0.00010468062 D = -3.7087444e - 006 E = 4.1943319e - 005 F = -1.4465194e - 005 G = 1.9195662e - 006

Designed in accordance with the second embodiment above and its second numerical embodiment, as shown in the ninth, tenth, eleventh to eleventh, and twelfth, respectively, the second The miniature image taking lens of the embodiment has a good correcting effect on field curvature, distortion aberration, comet aberration and longitudinal spherical aberration, and can satisfy the requirement of high pixel. In addition, the thirteenth graph shows the characteristic curve of the MTF modulation transfer function, which shows that the miniature image taking lens of the second embodiment of the present invention has good contrast characteristics and resolution performance. FIG. 14 is a schematic diagram showing the phase contrast (refer to the percentage of the central illumination of the screen and the peripheral illumination), showing that the miniature image taking lens of the second embodiment of the present invention has good light transmission efficiency.

Third embodiment

Referring to the third embodiment of the miniature image taking lens of the present invention shown in the fifteenth figure, the first embodiment is different from the first embodiment shown in the first figure in the first lens to the fourth lens L1. The L4 is an aspherical lens made of plastic. In the third embodiment, preferably, both surfaces of each of the first and second lenses L1 and L2 are aspherical, and the object-side surface S6 of the third lens L3 is aspherical, and the image of the fourth lens L4 The square surface S8 is also aspherical.

The miniature image taking lens of the third embodiment of the present invention satisfies the following conditional expression (1): -0.5 < (2Gf / 1Gf) < 0 (1)

Here, 1Gf is the focal length of the first lens group G1, and 2Gf is the focal length of the second lens group G2.

The miniature image taking lens of the third embodiment of the present invention further satisfies the following conditional expression (5): -4.5 < (L1f / L2f) < - 3.5 (5)

Here, L1f is the focal length of the first lens L1, and L2f is the focal length of the second lens L2.

The miniature image taking lens of the third embodiment of the present invention satisfies the following conditional expression (3): -1.5 < (L3f / L4f) < - 0.5 (3)

Here, L3f is the focal length of the third lens L3, and L4f is the focal length of the fourth lens L4.

According to the conditions of the third embodiment above, the relevant numerical values of the third numerical embodiment of the micro imaging lens of the present invention will be listed in detail below, as shown in Tables 5 and 6.

As shown in Table 5, in the third embodiment, both surfaces S1, S2 of the first lens L1, both surfaces S4, S5 of the second lens L2, the object surface S6 of the third lens L3, and the fourth lens L4 The image surface S9 is aspherical.

In the third embodiment, the specific values of the aspherical coefficients are: Surface number S1 (object-side surface of the first lens L1): A=0.014076683 B=0.0041829274 C=-0.0049735487 D=0.0036086819 E=-0.0018147872 F=0.00054321128 G=-6.9697923e-005

Surface number S2 (image surface of the first lens L1): A=-0.030525004 B=0.045422514 C=-0.023900737 D=-0.0021963248 E=0.0087902249 F=-0.0032264782 G=0.00019896892

Surface number S4 (object-side surface of the second lens L2): A=0.0036332926 B=-0.054843677 C=0.1016071 D=-0.10117618 E=0.018635526 F=0.030467158 G=-0.015415026

Surface number S5 (image side surface of the second lens L2): A=0.0010448169 B=-0.00061015882 C=0.0022678218 D=-0.0015767344 E=0.00054648251 F=-8.5704622e-005 G=5.8302332e-006

Surface number S6 (object-side surface of the third lens L3): A=-0.0026104859 B=0.0010495525 C=-0.00018515284 D=-1.7664494e-005 E=9.0355572e-006 F=-1.3623116e-007 G=-1.3683447e -007

Surface number S8 (image side surface of the fourth lens L4): A=0.0013185684 B=-0.00018248401 C=0.00026122546 D=-0.00017294818 E=6.2833262e-005 F=-1.1116447e-005 G=6.9943175e-007

According to the third embodiment and the third numerical embodiment thereof, as shown in the sixteenth, seventeenth, eighteenth to eighteenth and nineteenth, respectively, the present invention The miniature image taking lens of the third embodiment has a good correcting effect on field curvature, distortion aberration, comet aberration and longitudinal spherical aberration, and can satisfy the demand of high pixels. In addition, as shown in the twentieth For the MTF modulation transfer function characteristic curve, the micro image taking lens of the third embodiment of the present invention has good contrast characteristics and resolution performance. FIG. 21 is a schematic diagram showing the phase contrast (refer to the percentage of the central illumination of the screen and the peripheral illumination), showing that the miniature image taking lens of the third embodiment of the present invention has good light transmission efficiency.

As is broadly understood from the above three embodiments, the miniature image taking lens of the present invention satisfies the following conditional expressions: -0.5 < (2Gf / 1Gf) < 0; - 4.5 < (L1f / L2f) < - 2; and - 1.5 < (L3f /L4f)<-0.5

Where 1Gf is the focal length of the first lens group, 2Gf is the focal length of the second lens group, L1f is the focal length of the first lens, L2f is the focal length of the second lens, L3f is the focal length of the third lens, and L4f is the fourth lens focal length.

Compared with the prior art, the miniature image taking lens of the present invention has only the negative and positive lens groups G1 and G2, that is, only composed of four lenses L1 to L4, and has the advantages of short size, simple structure and convenient assembly; The configuration of at least three aspherical lenses and the refractive power of each component lens can effectively correct various aberrations and chromatic aberrations, improve resolution and meet high pixel requirements; instead of the traditional ones, multiple aspherical plastic lenses are used. The spherical glass lens group, the aspherical glass lens or the aspherical composite lens can greatly reduce the cost, and can easily correct aberrations, shorten the optical total length of the lens, and improve the production yield. In addition, the third and fourth lenses L3 and L4 are glued together to avoid unnecessary tolerances, which makes the lens of the present invention easier to process and further reduces the cost.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. please. However, the above description is only the preferred embodiment of the present invention, and equivalent modifications or variations made by those skilled in the art to the spirit of the present invention are included in the scope of the appended claims.

First lens group ‧‧‧G1

Second lens group ‧‧‧G2

First lens ‧‧‧L1

Aperture stop ‧‧‧ST

Second lens ‧‧‧L2

Third lens ‧‧‧L3

Fourth lens ‧‧‧L4

Glass plate ‧ ‧ GP

Imaging surface ‧‧‧IP

Optical axis ‧‧ OA

‧‧‧OBJ

Like ‧‧‧IMA

Surface ‧‧S1, S2, S4, S5, S6, S7, S8, S9, S10, S11

The first figure is an optical structural view of a miniature image taking lens according to a first embodiment of the present invention.

The second drawing is a schematic diagram of the image of the miniature image taking lens of the present invention according to the first numerical embodiment.

The third figure is a schematic diagram of the distortion aberration of the miniature image taking lens of the present invention according to the first numerical embodiment.

The fourth to fourth F diagrams are schematic diagrams of the comet aberration of the micro imaging lens of the present invention according to the first numerical embodiment.

The fifth drawing is a schematic diagram of the longitudinal spherical aberration of the micro imaging lens of the present invention according to the first numerical embodiment.

The sixth drawing is a schematic diagram of the MTF characteristic curve of the micro image taking lens of the present invention according to the first numerical embodiment.

The seventh drawing is a schematic diagram of the relative illuminance of the miniature image taking lens of the present invention according to the first numerical embodiment.

Figure 8 is an optical structural view of a miniature image taking lens of a second embodiment of the present invention.

The ninth drawing is a schematic diagram of the image of the miniature image taking lens of the present invention according to the second numerical embodiment.

The tenth drawing is a schematic diagram of distortion aberration of the micro image taking lens of the present invention according to the second numerical embodiment.

11A to 11F are drawings of the miniature image taking lens of the present invention according to the second numerical embodiment A diagram of the comet aberration.

Figure 12 is a schematic diagram showing the longitudinal spherical aberration of the miniature image taking lens of the present invention in accordance with the second numerical embodiment.

The thirteenth drawing is a schematic diagram showing the MTF characteristic curve of the micro image taking lens of the present invention according to the second numerical embodiment.

Fig. 14 is a schematic diagram showing the relative illuminance of the miniature image taking lens of the present invention in accordance with the second numerical embodiment.

Fig. 15 is an optical structural view of a miniature image taking lens of a third embodiment of the present invention.

Fig. 16 is a schematic view showing the image of the miniature image taking lens of the present invention in accordance with the third numerical embodiment.

Fig. 17 is a schematic diagram showing the distortion aberration of the miniature image taking lens of the present invention according to the third numerical embodiment.

The eighteenth through eighteenth Fth drawings are schematic diagrams of the comet aberration of the miniature image taking lens of the present invention according to the third numerical embodiment.

Fig. 19 is a schematic diagram showing the longitudinal spherical aberration of the micro imaging lens of the present invention according to the third numerical embodiment.

Fig. 20 is a schematic diagram showing the MTF characteristic curve of the micro imaging lens of the present invention according to the third numerical embodiment.

The twenty-first embodiment is a schematic diagram of the relative illuminance of the miniature image taking lens of the present invention according to the third numerical embodiment.

First lens group ‧‧‧G1

Second lens group ‧‧‧G2

First lens ‧‧‧L1

Aperture stop ‧‧‧ST

Second lens ‧‧‧L2

Third lens ‧‧‧L3

Fourth lens ‧‧‧L4

Glass plate ‧ ‧ GP

Imaging surface ‧‧‧IP

Optical axis ‧‧ OA

‧‧‧OBJ

Like ‧‧‧IMA

Surface ‧‧S1, S2, S4, S5, S6, S7, S8, S9, S10

Claims (19)

A miniature image taking lens sequentially includes a first lens group having a negative refracting power, an aperture stop, and a second lens group having a positive refracting power from the object side to the image side along the optical axis, wherein the first lens group Consisting of a first lens having a negative refractive power, the first lens is a crescent-shaped negative lens having a concave surface facing the object side and a convex surface facing the image side; the second lens group is from the object side to the image side edge The optical axis is sequentially composed of a second lens having positive refracting power, a third lens having positive refracting power, and a fourth lens having negative refracting power; the miniature image capturing lens includes at least three aspherical lenses and satisfies the following conditions Formula: -0.5 < (2Gf / 1Gf) < 0 where 1Gf is the focal length of the first lens group, and 2Gf is the focal length of the second lens group. The miniature image taking lens of claim 1, wherein the first lens is a plastic aspherical lens, and the concave surface and the convex surface are aspherical surfaces. The micro-image taking lens of claim 1, wherein the second lens is a crescent-shaped positive lens having a concave surface facing the object side and a convex surface facing the image side; the third lens is a A double convex positive lens; the fourth lens is a double concave negative lens. The miniature image taking lens of claim 3, wherein the second lens is a plastic aspherical lens, and the concave surface and the convex surface are aspherical surfaces. The miniature image taking lens of claim 4, wherein the third lens is a glass spherical lens or a plastic aspheric lens. The miniature image taking lens of claim 5, wherein the fourth lens is a A plastic aspherical lens whose image surface is an aspherical surface. For example, the miniature image taking lens described in claim 1 further satisfies the following conditional expression: -0.5<(2Gf/1Gf)<0 -4.5<(L1f/L2f)<-2 -1.5<(L3f/L4f) <-0.5 wherein L1f is the focal length of the first lens, and L2f is the focal length of the second lens. The miniature image taking lens according to claim 1 further satisfies the following conditional expression: -1.5 < (L3f / L4f) < - 0.5, wherein L3f is the focal length of the third lens, and L4f is the focal length of the fourth lens. The micro-capture lens of claim 1, wherein the first lens, the second lens, and the fourth lens are all aspherical lenses. The micro-capture lens of claim 9, wherein both surfaces of the first lens are aspherical. The micro-capture lens of claim 9, wherein both surfaces of the second lens are aspherical. The miniature image taking lens of claim 9, wherein the image side surface of the fourth lens is aspherical. The miniature image taking lens of claim 9, wherein the third lens is a glass spherical lens. The miniature image taking lens of claim 9, wherein the third lens comprises at least one aspherical surface. The miniature image taking lens of claim 1, wherein the three aspherical lenses The face lenses are all plastic aspherical lenses. The micro imaging lens of claim 1, wherein the third lens and the fourth lens are glued together. The micro-capture lens of claim 1, wherein a glass plate is further disposed between the second lens group and the imaging surface. A miniature image taking lens sequentially includes a first lens group having a negative refracting power, an aperture stop, and a second lens group having a positive refracting power from the object side to the image side along the optical axis, wherein the first lens group Consisting of a first lens having a negative refractive power, the first lens is a crescent-shaped negative lens having a concave surface facing the object side and a convex surface facing the image side; the second lens group is from the object side to the image side edge The optical axis is sequentially composed of a second lens having positive refracting power, a third lens having positive refracting power, and a fourth lens having negative refracting power; the miniature image capturing lens includes at least three aspherical lenses and satisfies the following conditions Formula: -4.5 < (L1f / L2f) < - 2 where L1f is the focal length of the first lens, and L2f is the focal length of the second lens. A miniature image taking lens sequentially includes a first lens group having a negative refracting power, an aperture stop, and a second lens group having a positive refracting power from the object side to the image side along the optical axis, wherein the first lens group Consisting of a first lens having a negative refractive power, the first lens is a crescent-shaped negative lens having a concave surface facing the object side and a convex surface facing the image side; the second lens group is from the object side to the image side edge The optical axis is sequentially composed of a second lens having positive refracting power, a third lens having positive refracting power, and a fourth lens having negative refracting power; the miniature image capturing lens includes at least three aspherical lenses and satisfies the following Formula: -1.5 < (L3f / L4f) < - 0.5 where L3f is the focal length of the third lens, and L4f is the focal length of the fourth lens.