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Zoom lens, camera, information device and portable information terminal device

A zoom lens and focal length technology, applied in the field of zoom lens, can solve the problem of large moving amount of focus, and achieve the effects of high speed, reduced driving energy, and light weight

Active Publication Date: 2012-08-15
RICOH KK
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] However, in the zoom lens described in Patent Document 4, the absolute value of the lateral magnification of the third lens group related to focusing is large, so focusing requires a large amount of movement, and the miniaturization of the zoom lens in use needs to be further improved.

Method used

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  • Zoom lens, camera, information device and portable information terminal device
  • Zoom lens, camera, information device and portable information terminal device
  • Zoom lens, camera, information device and portable information terminal device

Examples

Experimental program
Comparison scheme
Effect test

no. 1 approach 》

[0111] Figure 1 to Figure 5 The first embodiment of the present invention is shown.

[0112] The conditional formula (1) in the present invention represents the relationship between the focal length F2 of the second lens group and the focal length F3 of the third lens group. Since both the second lens group and the third lens group have negative refractive power, the focal lengths F2 and F3 are both negative.

[0113] If the upper limit of the conditional formula (1) is greater than -0.5, the energy of the third lens group to be calculated is relatively reduced, and the amount of movement during focusing increases, which hinders high-speed automatic focusing, or the energy of the second lens group The increase will cause the increase of the manufacturing error sensitivity, which is not conducive to the assembly performance of the lens.

[0114] On the contrary, if the lower limit value of the conditional formula (1) is less than -3.0, the energy of the third lens group incr...

Embodiment 1～5

[0139] Figure 1 to Figure 5 The zoom lenses shown are the zoom lenses of Examples 1 to 5, respectively.

[0140] The symbols in all the following examples (1 to 9) are as follows.

[0141] f: focal length of the whole system

[0142] F: F value

[0143] ω: half angle of view

[0144] R: Radius of curvature (aspheric surface is paraxial curvature radius)

[0145] D: distance between faces

[0146] Nd: Refractive index

[0147] vd: Abbe number

[0148] K: aspheric conic constant

[0149] A 4 : Quartic aspheric coefficient

[0150] A 6 : Sixth power aspheric coefficient

[0151] A 8 : Eighth power aspheric coefficient

[0152] A 10 : Tenth power aspheric coefficient

[0153]A 12 : Twelfth power aspheric coefficient

[0154] A 14 : Fourteenth power aspherical coefficient

[0155] The aspherical surface is represented by the well-known following formula, where C is the reciprocal of the paraxial curvature radius, that is, the paraxial curvature, H is the height ...

Embodiment 1

[0161] figure 1 The structure of the zoom lens of Example 1 is shown. Such as figure 1 As shown, the first lens group G1 of the zoom lens in Example 1 is configured such that a negative crescent lens (first lens L1) with a convex surface facing the subject and a negative crescent lens (first lens L1) with a convex surface facing the subject are provided in order from the subject side. positive crescent lens (second lens L2) on one side of the body.

[0162] The second lens group G2 is composed of three lenses, that is, a negative crescent lens (third lens L3) with a convex surface facing the subject and an aspherical surface on the subject side is arranged sequentially from the subject side. A biconcave negative lens (fourth lens L4 ) with a larger concave surface on the imaging side, and a biconvex positive lens (fifth lens L5 ) with a larger convex surface on the subject side.

[0163] The third lens group G3 is composed of one biconcave lens (sixth lens L6 ) whose concav...

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Abstract

The present invention relates to a zoom lens, a camera with the zoom lens as a photographing optical system, an information device and a portable information terminal device. The invention aims to provide a high-performance small-size zoom lens which has the following advantages: high setting density of focusing lens set, small focusing movement amount, high semi visual angle which is above 36.8 DEG at wide angle, zoom ratio in about 1.5-5 times, and high definition which corresponds to the photographing component with pixels between 5,000,000 and 10,000,000. The zoom lens is provided with the following components from a photographed member side along an optical axis: a first lens group (G1) which has positive refraction power, a second lens group (G2) which has negative refraction power, a third lens group (G3) which has negative refraction power, a fourth lens group (G4) which has positive refraction power, and a fifth lens group (G5) which has positive refraction power. The third lens group performs focusing. The focal lengths and wide angles of the second lens group and the third lens group and a geometric mean of the whole system focal length in looking in the distance satisfy a preset conditional expression.

Description

technical field [0001] The present invention relates to a zoom lens, a camera using the zoom lens as a photographing optical system, an information device, and a portable information terminal device. Background technique [0002] In recent years, zoom lenses have been widely used as photographic optical systems in information devices such as digital cameras. In particular, zoom lenses with a focal length range of approximately 50mm in terms of angle of view when converted to a 35mm silver halide camera are widely known. For these zoom lenses, users have further requested miniaturization, wide-angle, and high-speed autofocus. [0003] The above-mentioned zoom lens has a structure in which a first lens group with positive refractive power, a second lens group with negative refractive power, and subsequent lens groups are sequentially arranged from the subject side to the imaging side, and can take into account a large zoom ratio. This is a so-called positive-lead type zoom l...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G02B15/17G03B17/12G03B29/00G03B30/00
Inventor 高野洋平厚海广道
Owner RICOH KK
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