Zoom lens

A zoom lens and lens group technology, applied in the field of zoom lenses, can solve problems such as defocus and chromatic aberration, achieve the effect of shortening the total length and realizing a large aperture ratio

Inactive Publication Date: 2015-04-29
TAMRON
View PDF6 Cites 4 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] In general, in a lens system designed for use in the visible light region, especially, chromatic aberration occurs in the near-infrared region, thereby causing defocus when shooting with near-infrared rays at night

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Zoom lens
  • Zoom lens
  • Zoom lens

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0083] figure 1 It is a sectional view along the optical axis showing the structure of the zoom lens according to the first embodiment. In this zoom lens, the first lens group G having negative refractive power is sequentially arranged on the object side not shown in the figure. 11 , an aperture stop ST that specifies a predetermined aperture, and a second lens group G with positive refractive power 12 . In the second lens group G 12 A cover glass CG is disposed between the imaging surface IMG and the imaging plane IMG. The cover glass CG is a member arranged as needed, and can be omitted when unnecessary. Furthermore, a light receiving surface of an imaging element such as a CCD or a CMOS is disposed on the imaging surface IMG.

[0084] The first lens group G 11 Negative lens L arranged in order from the object side 111 , negative lens L 112 , and positive lens L 113 made. Negative lens L 111 Consists of a meniscus lens with the convex surface facing the object sid...

Embodiment 2

[0164] image 3It is a sectional view along the optical axis showing the structure of the zoom lens according to the second embodiment. The zoom lens is arranged sequentially from the object side not shown, and has a first lens group G having negative refractive power. 21 , an aperture stop ST that specifies a predetermined aperture, and a second lens group G with positive refractive power 22 . In the second lens group G 22 A cover glass CG is disposed between the imaging surface IMG and the imaging plane IMG. The cover glass CG is a member arranged as needed, and can be omitted when unnecessary. Furthermore, a light receiving surface of an imaging element such as a CCD or a CMOS is disposed on the imaging surface IMG.

[0165] The first lens group G 21 Negative lens L arranged in order from the object side 211 , negative lens L 212 , and the positive lens L 213 made. Negative lens L 211 Consists of a meniscus lens with the convex surface facing the object side. Ne...

Embodiment 3

[0245] Figure 5 It is a sectional view along the optical axis showing the structure of the zoom lens according to the third embodiment. The zoom lens is arranged sequentially from the object side not shown, and has a first lens group G having negative refractive power. 31 , an aperture stop ST that specifies a predetermined aperture, and a second lens group G with positive refractive power 32 . In the second lens group G 32 A cover glass CG is disposed between the imaging surface IMG and the imaging plane IMG. The cover glass CG is a member arranged as needed, and can be omitted when unnecessary. Furthermore, a light receiving surface of an imaging element such as a CCD or a CMOS is disposed on the imaging surface IMG.

[0246] The first lens group G 31 Negative lens L arranged in order from the object side 311 , negative lens L 312 , and the positive lens L 313 made. Negative lens L 311 Consists of a meniscus lens with the convex surface facing the object side. N...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

No PUM Login to view more

Abstract

A zoom lens includes sequentially from an object side a first lens group having a negative refractive power; an aberture stop; and a second lens group having a positive refractive power. The second lens group is moved along an optical axis toward the object side to zoom from a wide angle edge to a telephoto edge. The first lens group is moved along the optical axis toward en image side to correct image plane variation accompanying zooming. The second lens group includes sequentially from the object side, a positive lens having at least one aspheric surface, and a cemented lens configured by a negative lens, a positive lens, and a negative lens. The zoom lens satisfies a conditional expression (1) 1.8<D2 / Z<2.3, where D2 indicates an amount of movement of the second lens group, accompanying zooming from the wide angle edge to the telephoto edge, and Z indicates a zoom ratio.

Description

technical field [0001] The present invention relates to a zoom lens for a surveillance camera that can be used in a video camera, an electronic still camera, etc., and is particularly suitable for shooting day and night. Background technique [0002] Conventionally, monitoring cameras such as CCTV (Closed Circuit TeleVision) have been widely used for monitoring unmanned facilities. Surveillance cameras are mostly used for daytime photography with visible light and nighttime for near-infrared photography. Therefore, surveillance cameras are required to use lens systems that can be used regardless of day and night, that is, lens systems that can cope with light in both the visible light region and the near-infrared region. [0003] In general, in a lens system designed for use in the visible region, especially, chromatic aberration occurs in the near-infrared region, thereby causing defocus when shooting with near-infrared rays at night. In contrast, as a lens system mounted...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
Patent Type & Authority Applications(China)
IPC IPC(8): G02B15/177
CPCG02B15/1425
Inventor 未来
Owner TAMRON
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap