Imaging module with high resolution and compact size

An imaging module comprising,

• an imaging lens system comprising, in the order from the object side to the image side thereof, a first lens of positive refraction power, a second lens of negative refraction power, a third lens of positive refraction power, and a fourth lens of negative refraction power;
• and
• an image sensor placed aligned with the imaging lens system and placed at the image side of the imaging lens system,
• wherein the imaging module satisfying the formulas:
• D/T≧1.1,
• −3.5<R2/F1<1.5,
• −2.5<R3/F2<−0.5, and
• 1.5<|R7/F4|<3.5,
• wherein D is the diagonal length of the sensing area of the image sensor, T is the length from the object surface of the first lens to the sensing surface of the image sensor, R2 is the radius of curvature of the image side surface of the first lens, F1 is the focal length of the first lens, R3 is the radius of curvature of the object side surface of the second lens, F2 is the focal length of the second lens, R7 is the radius of curvature of the object side surface of the fourth lens, F4 is the focal length of the fourth lens.