| 摘要 |
A mini fixed focus lens module is provided. From an object end to an image end thereof, the mini fixed focus lens module sequentially includes a first lens, a second lens, a third lens and a fourth lens. The first lens has a positive diopter, the second lens has a negative diopter, the third lens has a positive diopter, the fourth lens has a negative diopter, a combined diopter of the second and third lenses is positive, and the mini fixed focus lens module satisfies the following formula: 0.2<f23/f<1 , wherein f23 is a combined focal length of the second and third lenses, and f is a system focal length of the mini fixed focus lens module. The invention arranges the first, second, third and fourth lenses to control a ratio of the combined focal length to the system focal length.
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