CN104730692B - Full-frame lens of micro single-lens reflex camera - Google Patents

Abstract

The full-frame lens for mirrorless digital cameras mainly provides a full-frame lens for mirrorless digital cameras to solve the problems of spherical aberration and low imaging quality caused by the use of spherical mirrors in existing lenses. The full-frame lens of the mirrorless digital camera includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens and a ninth lens in order from the object side. The present invention adopts a compact design of a spherical surface and an aspherical surface, avoids the spherical aberration caused by all spherical mirrors, simplifies the structure and improves the imaging quality, and has a large field of view, and is suitable for shooting portraits, landscapes, and humanistic sketches. The lenses are all made of glass, which improves the performance parameters of a single lens, improves the yield rate of the entire lens and facilitates actual production.

Description

Mirrorless digital camera full frame lens

technical field

The invention relates to a full-frame lens for a mirrorless digital camera, specifically a full-frame lens for a mirrorless digital camera with a specification of 35mm f2.0, belonging to the field of camera lens preparation.

Background technique

The history of human development proves that no technology can be brilliant forever. In the film era, the medium for storing images - film must be strictly protected from light leakage when framing. However, in the digital age, the situation has changed fundamentally - CCD is not afraid of light leakage. It can be used not only for framing, but also for imaging after being cleared. Therefore, the necessity of the existence of the reflector has been greatly reduced. Its working principle determines that the viewfinder of the reflector is not suitable for digital photography. On an electronic digital camera, there is no need to keep a mechanical part - the mirror. Although people can tolerate the bulky and complex structure of the reflector because it can take into account the viewfinder through the lens and the protection of the film from light leakage, but the characteristics of image sensors in the digital age that are not afraid of light leakage make the existence of the reflector unnecessary. With the improvement of electronic viewfinder technology, one day, the clarity and brightness of electronic viewfinder will be good enough to replace the mirror sooner or later. So, in theory, a mirrorless camera can have almost all the advantages of a SLR camera. Once the waiting demand breaks out, such problems will definitely be solved. This lens is specially designed for mirrorless cameras. Compared with SLR lenses, it is smaller and of higher quality.

Contents of the invention

In order to solve the above problems, a full-frame lens for a mirrorless digital camera is provided. The full-frame lens of the micro-single digital camera adopts a spherical and aspherical compact design, which avoids the spherical aberration caused by all spherical lenses, simplifies the structure and improves the imaging quality. The field of view is large, suitable for shooting portraits, landscapes, and cultural sketches. The lenses are all made of glass, which improves the performance parameters of a single lens. The yield rate of the whole lens can be improved and the actual production is convenient.

To achieve the above object, the present invention adopts the following technical solutions:

A full-frame lens for a mirrorless digital camera, which sequentially includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a ninth lens from the object side; , the first lens is a double-concave spherical negative lens, including a concave first spherical surface and a concave second spherical surface, and the second lens is a double-convex spherical positive lens, including a convex second spherical surface and a convex third spherical surface; the first lens It forms a cemented lens with the second lens; the third lens is a biconvex spherical positive lens, including a convex fourth spherical surface and a convex fifth spherical surface; the fourth lens is a double concave spherical negative lens, including a concave fifth spherical surface and a concave sixth spherical surface ; the third lens and the fourth lens form a cemented lens; the fifth lens is an aspheric meniscus negative lens, including the seventh aspheric concave surface and the eighth aspheric convex surface; the sixth lens is a double concave spherical negative lens, including the fourth concave concave Nine spheres and a concave tenth sphere; the seventh lens is a biconvex spherical positive lens, including the convex tenth sphere and the convex eleventh sphere; the sixth lens and the seventh lens form a cemented lens; the eighth lens is a biconvex spherical positive lens , including the convex twelfth sphere and the convex thirteenth sphere; the ninth lens is a double-concave spherical negative lens, including the concave thirteenth sphere and the concave fourteenth sphere; the eighth lens and the ninth lens form a cemented lens; the first The lens to the ninth lens are all made of glass; the aperture is located on the object side, between the fourth lens and the fifth lens.

The refractive index of the first lens is greater than 1.4 and less than 1.6, and its dispersion is greater than 50 and less than 75, preferably HK51CDGM glass, whose refractive index and dispersion are 1.523 and 58.6, respectively.

The refractive index of the second lens is greater than 1.75 and less than 1.85, and its dispersion is greater than 35 and less than 50, preferably HZLAF50BCDGM. The refractive index and dispersion are 1.804 and 46.5, respectively.

The refractive index of the third lens is greater than 1.75 and less than 1.85, and its dispersion is greater than 35 and less than 50, preferably HZLAF50BCDGM. The refractive index and dispersion are 1.804 and 46.5, respectively.

The refractive index of the fourth lens is greater than 1.6 and less than 1.9, and its dispersion is greater than 20 and less than 35. It is preferably HZF4CDGM glass, and its refractive index and dispersion are 1.728 and 28.3, respectively.

The refractive index of the fifth lens is greater than 1.65 and less than 1.80, and its dispersion is greater than 20 and less than 35. It is preferably Japan SUMITA KCD120 special molded glass for low melting point aspheric surface, and its refractive index and dispersion are 1.7225 and 29.2, respectively.

The refractive index of the sixth lens is greater than 1.4 and less than 1.65, and its dispersion is greater than 65 and less than 75. HQK3CDGM is preferably used, and the refractive index and dispersion are 1.487 and 70.1, respectively.

The refractive index of the seventh lens is greater than 1.75 and less than 1.9, and its dispersion is greater than 35 and less than 50. Preferably, HZLAF55C CDGM is used, and the refractive index and dispersion are 1.83500 and 42.97, respectively.

The refractive index of the eighth lens is greater than 1.75 and less than 1.85, and its dispersion is greater than 35 and less than 50, preferably HZLAF50BCDGM, and the refractive index and dispersion are 1.804 and 46.5 respectively; Less than 35, preferably HZF10 CDGM glass, the refractive index and dispersion are 1.689 and 31.1, respectively.

The parameters of the full-frame lens of the mirrorless digital camera are:

; The seventh and eighth aspherical lens formulas and data are:

$\mathrm{<span\; class="notranslate">\; z</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; cr</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\sqrt{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; c</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; r</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; r</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; r</span>}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}{\mathrm{<span\; class="notranslate">\; r</span>}}^{\mathrm{<span\; class="notranslate">\; 6</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}{\mathrm{<span\; class="notranslate">\; r</span>}}^{\mathrm{<span\; class="notranslate">\; 8</span>}}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 5</span>}}{\mathrm{<span\; class="notranslate">\; r</span>}}^{\mathrm{<span\; class="notranslate">\; 10</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 6</span>}}{\mathrm{<span\; class="notranslate">\; r</span>}}^{\mathrm{<span\; class="notranslate">\; 12</span>}}<span\; class="notranslate">\; ...</span><span\; class="notranslate">\; ...</span>$

The beneficial effects of the present invention are:

The invention adopts the compact design of spherical surface plus aspheric surface, avoids spherical aberration caused by all spherical mirrors, simplifies structure and improves imaging quality. This mirrorless digital camera dedicated full-frame lens has a large field of view and is suitable for shooting portraits, landscapes, and cultural sketches. The lenses are all made of glass, which improves the performance parameters of a single lens. The yield rate of the whole lens can be improved and the actual production is convenient.

Description of drawings

Fig. 1 is the structural representation of digital camera full frame lens of the present invention;

Fig. 2 is the MTF figure of digital camera full frame lens of the present invention;

Fig. 3 is the field curvature diagram of the digital camera full-frame lens of the present invention;

Fig. 4 is the optical distortion diagram of the full-frame lens of the digital camera of the present invention;

Fig. 5 is a relative illuminance diagram of the full-frame lens of the digital camera of the present invention.

detailed description

With reference to Fig. 1-5, effective focal length of the present invention is f=35mm, and relative aperture is F=2, and the full field of view angle of whole optical system is 64 degree, and its total length of lens is 56mm, and structure is referring to Fig. 1, makes it can effectively Improve the performance of the lens.

Referring to Figure 1, the full-frame lens of a micro-single digital camera, which sequentially includes a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, a sixth lens 6, and a seventh lens from the object side 7. The eighth lens 8 and the ninth lens 9; wherein, the first lens 1 is a biconcave spherical negative lens, including a concave first spherical surface and a concave second spherical surface, and the second lens 2 is a biconvex spherical positive lens , including a convex second spherical surface and a convex third spherical surface; the first lens 1 and the second lens 2 form a cemented lens; the third lens 3 is a biconvex spherical positive lens, including a convex fourth spherical surface and a convex fifth spherical surface; the fourth lens 4 is a double concave spherical negative lens, including a concave fifth spherical surface and a concave sixth spherical surface; the third lens 3 and the fourth lens 4 form a cemented lens; the fifth lens 5 is an aspheric meniscus negative lens, including a concave seventh aspheric surface Spherical surface and convex surface eighth aspherical surface; sixth lens 6 is double concave spherical negative lens, including concave ninth spherical surface and concave tenth spherical surface; seventh lens 7 is double convex spherical positive lens, including convex tenth spherical surface and convex surface tenth spherical surface Eleven spherical surfaces; the sixth lens 6 and the seventh lens 7 form a cemented lens; the eighth lens 8 is a biconvex spherical positive lens, including a convex twelfth spherical surface and a convex thirteenth spherical surface; the ninth lens 9 is a double concave spherical negative The lens includes a concave 13th sphere and a concave 14th sphere; the eighth lens 8 and the ninth lens 9 form a cemented lens; the first lens 1 to the ninth lens 9 are all made of glass; the diaphragm 10 is located on the object side In terms of position, it is located between the fourth lens 4 and the fifth lens 5 .

The refractive index of the first lens 1 is greater than 1.4 and less than 1.6, and its dispersion is greater than 50 and less than 75, preferably HK51CDGM glass, and its refractive index and dispersion are 1.523 and 58.6, respectively.

The refractive index of the second lens 2 is greater than 1.75 and less than 1.85, and its dispersion is greater than 35 and less than 50, preferably HZLAF50BCDGM, and its refractive index and dispersion are 1.804 and 46.5, respectively.

The refractive index of the third lens 3 is greater than 1.75 and less than 1.85, and its dispersion is greater than 35 and less than 50, preferably HZLAF50BCDGM. The refractive index and dispersion are 1.804 and 46.5, respectively.

The refractive index of the fourth lens 4 is greater than 1.6 and less than 1.9, and its dispersion is greater than 20 and less than 35. It is preferably made of HZF4CDGM glass, and its refractive index and dispersion are 1.728 and 28.3, respectively.

The refractive index of the fifth lens 5 is greater than 1.65 and less than 1.80, and its dispersion is greater than 20 and less than 35. It is preferably Japan SUMITAKCD120 special molded glass for low melting point aspheric surface. The refractive index and dispersion are 1.7225 and 29.2 respectively.

The refractive index of the sixth lens 6 is greater than 1.4 and less than 1.65, and its dispersion is greater than 65 and less than 75. HQK3CDGM is preferably used, and the refractive index and dispersion are 1.487 and 70.1, respectively.

The refractive index of the seventh lens 7 is greater than 1.75 and less than 1.9, and its dispersion is greater than 35 and less than 50. It is preferable to use HZLAF55C CDGM, and the refractive index and dispersion are 1.83500 and 42.97 respectively.

The refractive index of the eighth lens 8 is greater than 1.75 and less than 1.85, and its dispersion is greater than 35 and less than 50, preferably HZLAF50BCDGM. The refractive index and dispersion are 1.804 and 46.5 respectively; the refractive index of the ninth lens 9 is greater than 1.6 and less than 1.9, and its dispersion is greater than 20 and less than 35 , preferably HZF10 CDGM glass, the refractive index and dispersion are 1.689, 31.1, respectively.

The parameters of the full-frame lens of the mirrorless digital camera are:

; The seventh and eighth aspherical lens formulas and data are:

$\mathrm{<span\; class="notranslate">\; z</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; cr</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\sqrt{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; c</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; r</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; r</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; r</span>}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}{\mathrm{<span\; class="notranslate">\; r</span>}}^{\mathrm{<span\; class="notranslate">\; 6</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}{\mathrm{<span\; class="notranslate">\; r</span>}}^{\mathrm{<span\; class="notranslate">\; 8</span>}}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 5</span>}}{\mathrm{<span\; class="notranslate">\; r</span>}}^{\mathrm{<span\; class="notranslate">\; 10</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 6</span>}}{\mathrm{<span\; class="notranslate">\; r</span>}}^{\mathrm{<span\; class="notranslate">\; 12</span>}}<span\; class="notranslate">\; ...</span><span\; class="notranslate">\; ...</span>$

Referring to Figure 2 for MTF performance, the diagonal half of the CMOS effective area is defined as the maximum image height, which is set to 1.0 field of view. In order to measure the spatial frequency of different image heights, 0.8 field of view, 0.6 field of view, and 0 field of view are used. In this embodiment, half of the CMOS diagonal is 21.6mm, that is, the image height of 1.0 field of view, the image height of 0.7 field of view is 21.6*0.7=15.12, the image height of 0.5 field of view is 21.6*0.5=10.8, and the image height of 0 field of view is 21.6*0.5=10.8. The image height is 0mm, which is the center point of CMOS.

Refer to Figure 3 to Figure 5 for spherical aberration, astigmatism, and illuminance. The meridian field curvature and sagittal field curvature of the digital camera full-frame lens are greater than -0.16mm and less than 0.12mm, and the optical distortion is greater than -0.09% and less than 0, all of which meet the imaging performance requirements . The relative illuminance of its edge reaches 33%, which meets the imaging performance requirements of modern ultra-high pixel (more than 24 million) mirrorless cameras.

Claims (10)

1. The full-frame lens of a micro-single digital camera is characterized in that it includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens in order from the object side , the ninth lens; wherein, the first lens is a biconcave spherical negative lens, including a concave first spherical surface and a concave second spherical surface, and the second lens is a biconvex spherical positive lens, including a convex second spherical surface and a convex second spherical surface. Three spherical surfaces; the first lens and the second lens form a cemented lens; the third lens is a biconvex spherical positive lens, including a convex fourth spherical surface and a convex fifth spherical surface; the fourth lens is a double concave spherical negative lens, including a concave fifth spherical surface Spherical and concave sixth spherical surface; the third lens and the fourth lens form a cemented lens; the fifth lens is an aspheric meniscus negative lens, including a concave seventh aspheric surface and a convex eighth aspherical surface; the sixth lens is a double concave spherical surface The negative lens includes the ninth spherical surface of the concave surface and the tenth spherical surface of the concave surface; the seventh lens is a biconvex spherical positive lens, including the tenth spherical surface of the convex surface and the eleventh spherical surface of the convex surface; the sixth lens and the seventh lens form a cemented lens; the eighth lens It is a biconvex spherical positive lens, including a convex twelfth sphere and a convex thirteenth sphere; the ninth lens is a biconcave negative lens, including a concave thirteenth sphere and a concave fourteenth sphere; the eighth lens and the ninth lens A cemented lens is formed; the first lens to the ninth lens are all made of glass; the aperture is located at the object position, between the fourth lens and the fifth lens. 2. The full-frame lens for a mirrorless digital camera according to claim 1, wherein the refractive index of the first lens is greater than 1.4 and less than 1.6, and its dispersion is greater than 50 and less than 75. 3. The full-frame lens for a mirrorless digital camera according to claim 1, wherein the refractive index of the second lens is greater than 1.75 and less than 1.85, and its dispersion is greater than 35 and less than 50. 4. The full-frame lens for a mirrorless digital camera according to claim 1, wherein the third lens has a refractive index greater than 1.75 and less than 1.85, and a dispersion greater than 35 and less than 50. 5. The full-frame lens for a mirrorless digital camera according to claim 1, wherein the refractive index of the fourth lens is greater than 1.6 and less than 1.9, and its dispersion is greater than 20 and less than 35. 6. The full-frame lens for a mirrorless digital camera according to claim 1, wherein the refractive index of the fifth lens is greater than 1.65 and less than 1.80, and its dispersion is greater than 20 and less than 35. 7. The full-frame lens for a mirrorless digital camera according to claim 1, wherein the refractive index of the sixth lens is greater than 1.4 and less than 1.65, and its dispersion is greater than 65 and less than 75. 8. The full-frame lens for a mirrorless digital camera according to claim 1, wherein the refractive index of the seventh lens is greater than 1.75 and less than 1.9, and its dispersion is greater than 35 and less than 50. 9. The full-frame lens for a mirrorless digital camera according to claim 1, wherein the refractive index of the eighth lens is greater than 1.75 and less than 1.85, and its dispersion is greater than 35 and less than 50; the refractive index of the ninth lens is greater than 1.6 Less than 1.9, its dispersion is greater than 20 and less than 35. 10. The full-frame lens of the mirrorless digital camera as claimed in claim 1, wherein the parameters of the full-frame lens of the mirrorless digital camera are: ; The seventh and eighth aspherical lens formulas and data are: $\mathrm{<span\; class="notranslate">\; z</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; cr</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\sqrt{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; c</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; r</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; r</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; r</span>}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}{\mathrm{<span\; class="notranslate">\; r</span>}}^{\mathrm{<span\; class="notranslate">\; 6</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}{\mathrm{<span\; class="notranslate">\; r</span>}}^{\mathrm{<span\; class="notranslate">\; 8</span>}}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 5</span>}}{\mathrm{<span\; class="notranslate">\; r</span>}}^{\mathrm{<span\; class="notranslate">\; 10</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 6</span>}}{\mathrm{<span\; class="notranslate">\; r</span>}}^{\mathrm{<span\; class="notranslate">\; 12</span>}}<span\; class="notranslate">\; ...</span><span\; class="notranslate">\; ...</span>$