Patent Application
20170123191
The subject matter herein generally relates to a wide angle lens system.
In the field of photography, a wide angle lens can capture an image of an object with a wide angle (the field angle>100°) of view in high resolution. Many mobile phones and image systems, such as a surveillance cameras, are now equipped with the wide angle lens. Conventionally, optical aberrations are larger when the field angle is wider, especially field curvatures, which lowers the resolution of the image.
Many aspects of the disclosure can be better understood with reference to the following drawing. The components in the drawing are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the disclosure. Implementations of the present technology will now be described, by way of example only, with reference to the attached figure.
It will be appreciated that for simplicity and clarity of illustration, where appropriate, reference numerals have been repeated among the different figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the embodiments described herein. However, it will be understood by those of ordinary skill in the art that the embodiments described herein can be practiced without these specific details. In other instances, methods, procedures and components have not been described in detail so as not to obscure the related relevant feature being described. Also, the description is not to be considered as limiting the scope of the embodiments described herein. The drawings are not necessarily to scale and the proportions of certain parts may be exaggerated to better illustrate details and features of the present disclosure.
A definition that applies throughout this disclosure will now be presented.
The term “comprising,” when utilized, means “including, but not necessarily limited to;” it specifically indicates open-ended inclusion or membership in the so-described combination, group, series and the like.
The present disclosure relates to a wide angle lens system.
The first lens 10 is an aspheric lens. The object side surface 12 and the image side surface 14 of the first lens 10 are an aspheric surface, the image side surface 14 of the first lens 10 includes a concave surface 142, and the concave surface 142 is configured to rotate symmetrically about a central optical axis of the first lens 10.
The aperture 20 is positioned on the object side surface 32 of the second lens 30, the aperture 20 is configured to rotate symmetrically about a central optical axis of the second lens 30. The aperture 20 is configured to control optical aberrations of light.
The second lens 30 is an aspheric lens. The object side surface 32 and the image side surface 34 of the second lens 30 are an aspheric surface. The image side surface 34 of the second lens 30 is a convex surface. A central optical axis of the second lens 30 is aligned with the central optical axis of the first lens 10.
The filter 40 is configured to transmit an infrared light with a wavelength range of 800-850 nm, and to filter out others like an ultraviolet light or a visible light.
The glass cover 50 is configured to protect the image plane 60 and keep the image plane 60 clean.
A light from an object couples to the wide angle lens system 100 and is focused by the first lens 10 and the second lens 30, the filter 40 and the glass cover 50 transmit the light to the image plane 60. The light is positioned on the image plane 60 and an image of the object is constituted on the image plane 60 by a sensor (not shown).
The wide angle lens system 100 satisfies the formulas:
5<TTL/f<7; (1)
−1.9</f<−1.0; (2)
1.0<f2/f<2.0; (3)
where TTL is a distance between the object side surface 12 of the first lens 10 and the image plane 60, f is a focal length of the wide angle lens system 100, f1 is a focal length of the first lens 10, f2 is a focal length of the second lens 20. Formula (1) is used for decreasing the total thickness of the wide angle lens system 100. Formula (2) is used for capturing the image of the object with high quality in a wide angle. Formula (3) is used for correcting the optical aberrations of the image.
In a first embodiment, the wide angle lens system 100 satisfies the parameters of Tables 1-2. The symbols listed below are used in Tables 1 and Table 2, where a diameter, L, of the aperture 20 is satisfied L=0.113 mm, a field angle, 2ω, of the wide angle lens system 100 is satisfied 2ω=123°. Listed below are the symbols used in Table 1:
R: a radius of curvature,
D: a distance between surfaces on the optical axis,
Nd: a refractive index of lens corresponding to a light of wavelength 850 nm,
Vd: an Abbe number corresponding to a light of wavelength 850 nm,
The even aspherical surfaces are shaped according to the formula:
where Z is a displacement of the z-component from the aspherical surface to a vertex of the aspherical surface, h is a height from the optical axis of the lenses to the aspherical surface, c is a radius of curvature, k is a conic constant, and Ai are i-th order correction coefficients of the aspherical surfaces.
In the first embodiment of the wide angle lens system 100, the wide angle lens system 100 satisfies TTL=3.9, f=0.6409, f1=−0.9159, f2=0.9795, TTL/f=6.085, f1/f=−1.429, f2/f=1.528.
In the first embodiment, the spherical aberration graph, the field curvature graph, and the distortion graph of the wide angle lens system 100 are respectively shown in
In a second embodiment, the wide angle lens system 100 satisfies the parameters of Tables 3-4. The symbols listed below are used in Tables 3 and Table 4, where a diameter of the aperture 20 is satisfied L=0.118 mm, a field angle of the wide angle lens system 100 is satisfied 2ω=121.4°. Listed below are the symbols used in Table 3:
R: a radius of curvature,
D: a distance between surfaces on the optical axis,
Nd: a refractive index of lens corresponding to a light of wavelength 850 nm,
Vd: an Abbe number corresponding to a light of wavelength 850 nm,
In the second embodiment of the wide angle lens system 100, the wide angle lens system 100 also satisfies TTL=3.9, f=0.66, f1=−0.85, f2=0.986, TTL/f=5.909, f1/f=−1.288, f2/f=1.494.
In the second embodiment, the spherical aberration graph, the field curvature graph, and the distortion graph of the wide angle lens system 100 are respectively shown in
The embodiments shown and described above are only examples. Many details are often found in the art such as the other features of a wide angle lens system. Therefore, many such details are neither shown nor described. Even though numerous characteristics and advantages of the present technology have been set forth in the foregoing description, together with details of the structure and function of the present disclosure, the disclosure is illustrative only, and changes may be made in the details, including in matters of shape, size, and arrangement of the parts within the principles of the present disclosure, up to and including the full extent established by the broad general meaning of the terms used in the claims. It will therefore be appreciated that the embodiments described above may be modified within the scope of the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 104135943 | Oct 2015 | TW | national |
