Image sensors

1. An image sensor, comprising:

a semiconductor substrate containing a plurality of photoelectric conversion elements;

a filter array, including a first color filter, a second color filter, a third color filter and an infrared filter, disposed above the semiconductor substrate;

an isolated partition disposed in the filter array to surround one of the first, second and third color filters and the infrared filter, wherein the isolated partition has a refractive index that is lower than the refractive indexes of the first, second and third color filters and the refractive index of the infrared filter, wherein an area of the isolated partition and the one of the first filter, the second filter, the third filter and the infrared filter surrounded by the isolated partition added together is equal to the area of the other one of the first filter, the second filter, the third filter and the infrared filter that is not surrounded by the isolated partition; and

an additional isolated partition disposed in the filter array, wherein the filter array includes a red color filter, a green color filter, a blue color filter and the infrared filter, the isolated partition and the additional isolated partition surround the red and the blue color filters, respectively, and the infrared filter is in contact with the green color filter.

2. The image sensor as claimed in claim 1 , wherein a material of the isolated partition and the additional isolated partition include silicon oxide or a material with a refractive index that is lower than the refractive index of silicon oxide.

3. The image sensor as claimed in claim 1 , further comprising a microlens structure disposed above the filter array, wherein a material of the isolated partition and the additional isolated partition are the same as the material of the microlens structure.

4. The image sensor as claimed in claim 1 , wherein an area of the isolated partition and one red color filter surrounded by the isolated partition added together, an area of the additional isolated partition and one blue color filter surrounded by the additional isolated partition added together, an area of one green color filter, and an area of one infrared filter are equal.

5. The image sensor as claimed in claim 1 , further comprising:

a microlens structure disposed above the filter array;

a light-shielding layer disposed underneath the filter array;

a high dielectric-constant film disposed on the semiconductor substrate;

a buffer layer disposed on the high dielectric-constant film; and

a passivation layer disposed on the buffer layer and covering the light-shielding layer.

6. The image sensor as claimed in claim 1 , further comprising:

a microlens structure disposed above the filter array;

a high dielectric-constant film disposed on the semiconductor substrate;

a buffer layer disposed on the high dielectric-constant film; and

a light-shielding layer and the filter array disposed on the top surface of the buffer layer, wherein the light-shielding layer has the shape of a grid and is disposed between the first, second and third color filters and the infrared filter, the top of the light-shielding layer is lower than the top of the filter array, and the isolated partition is disposed on the light-shielding layer.

7. The image sensor as claimed in claim 1 , wherein the filter array is arranged with eight green color filters, four infrared filters, two red color filters and two blue color filters in a repeat unit of the filter array, or is arranged with eight green color filters, four blue color filters, two red color filters and two infrared filters in a repeat unit of the filter array.