Exposure-suppressing imaging system

1. An exposure-suppressing imaging system installed in motor vehicle comprising:

a first optical assembly forming a first image of an object at a focal plane thereof and having:

a first lens having a central concavity which radius is −5.73 to −7 mm defined on a first surface thereof and a convexity which radius is −7.65 to −9.35 mm defined on a second surface thereof;

a second lens having convexities respectively defined on a first surface and a second surface thereof with radiuses 17.36 to 21.21 mm and −10.86 to −13.28 mm respectively;

a third lens having a central concavity which radius is −8.85 to −10.81 mm defined on a first surface thereof and a planar area defined on a second surface thereof;

a fourth lens having a convexity which radius is 13.53 to 16.53 mm defined on a first surface thereof and a planar defined on a second surface thereof,

wherein the first lens, the second lens, the third lens and the fourth lens are sequentially centered on a common optical axis;

a beam splitter positioned between the first optical assembly and the focal plane of the first optical assembly;

an LCOS reflective light modulator positioned on the focal plane, and selectively and partially altering the reflectivity thereof to reflect the first image back to the beam splitter;

a second optical assembly positioned on a side of the beam splitter and receiving the reflected first image to form a second image on a focal plane of the second optical assembly, and having:

a fifth lens having a concavity which radius is −45.71 to −55.87 mm defined on a first surface thereof and a convexity which radius is −13.13 to −16.05 mm defined on a second surface thereof;

a sixth lens having convexities which radiuses are 11.18 to 13.66 mm respectively defined on a first surface and a second surface thereof;

a seventh lens coupled to the sixth lens, having a concavity which radius is −6.12 to −7.57 mm defined on a first surface thereof and a planar area defined on a second surface thereof;

an eighth lens having convexities which radiuses are 6.63 to 8.1 mm and −25.43 to −31.08 mm respectively defined on a first surface and a second surface thereof; and

a ninth lens having a central concavity which radius is −3.30 to −4.03 mm defined on a first surface thereof and a planar area defined on a second surface thereof,

in which the fifth lens, the sixth lens, the seventh lens, the eighth lens and the ninth lens are sequentially centered on the common optical axis;

a light sensor positioned on the focal plane of the second optical assembly and converting the second image into a signal; and

a controller receiving the signal and computing the signal to generate a third image, and selectively controlling the reflectivity of the LCOS reflective light modulator according to whether the signal contains information of overexposure on the third image.

2. The exposure-suppressing imaging system as claimed in claim 1 , wherein the first optical assembly has a focal length of 17 mm and a F-number of 8.

3. The exposure-suppressing imaging system as claimed in claim 1 , wherein the second optical assembly has a focal length of 8.24 mm.

4. The exposure-suppressing imaging system as claimed in claim 2 , wherein the second optical assembly has a focal length of 8.24 mm.

5. The exposure-suppressing imaging system as claimed in claim 1 , wherein the first optical assembly is a telecentric optical imaging system.

6. The exposure-suppressing imaging system as claimed in claim 2 , wherein the first optical assembly is a telecentric optical imaging system.

7. The exposure-suppressing imaging system as claimed in claim 4 , wherein the first optical assembly is a telecentric optical imaging system.