Abstract: A high dynamic range image sensor may include a plurality of pixel groups. One or more pixel groups may include attenuated pixels in addition to unattenuated pixels. The unattenuated pixels may include a photosensitive area, a color filter element and a microlens of a first size. Each attenuated pixel may include a photosensitive area, a color filter element, a neutral density filter, and a microlens of a second size that is smaller than the first size. The color filter elements for each pixel in a given pixel group may be the same color. The neutral density filter may attenuate light for the attenuated pixels, increasing dynamic range of the image sensor. The microlenses of varying sizes may redirect light from attenuated pixels towards unattenuated pixels, further increasing the dynamic range.

Abstract: An image sensor may include one or more phase detection pixel groups. A phase detection pixel group may include at least two phase detection pixels with respective photosensitive areas and a per-group microlens that covers all of the phase detection pixels in that group. Each phase detection pixel may have an asymmetric response to incident light. The phase detection pixel group may also include per-pixel microlenses that each cover a respective photosensitive area of a phase detection pixel. The per-group microlens may overlap the per-pixel microlenses. A low-index filler may be interposed between the per-group microlens and the per-pixel microlenses. The per-pixel microlenses may be incorporated into phase detection pixel groups in both front-side illuminated image sensors and back-side illuminated image sensors. The phase detection pixel groups may have a 2×2 arrangement.

Abstract: A high dynamic range image sensor may include a plurality of pixel groups. One or more pixel groups may include attenuated pixels in addition to unattenuated pixels. The unattenuated pixels may include a photosensitive area, a color filter element and a microlens of a first size. Each attenuated pixel may include a photosensitive area, a color filter element, a neutral density filter, and a microlens of a second size that is smaller than the first size. The color filter elements for each pixel in a given pixel group may be the same color. The neutral density filter may attenuate light for the attenuated pixels, increasing dynamic range of the image sensor. The microlenses of varying sizes may redirect light from attenuated pixels towards unattenuated pixels, further increasing the dynamic range.

Abstract: An imaging device may have an array of image sensor pixels that includes infrared image pixels. Backside and frontside reflectors may be incorporated into the infrared pixels to increase effective thicknesses of photosensitive regions within the pixels. In other words, light incident on each pixel may be reflected and traverse the photosensitive region multiple times, thereby allowing silicon in the photosensitive region to absorb infrared light more efficiently. The backside reflector may be interposed between the silicon and a microlens, which may have a toroidal shape to direct light around the backside reflector. If desired, the toroidal lens may have a concave opening. Alternatively, the backside reflector may be ring-shaped, and a spherical microlens may focus light through a center portion of the reflector. A top surface of the silicon layer may be curved to focus light toward the center of the photosensitive region and improve pixel efficiency.

Abstract: An imaging device may have an array of image sensor pixels that includes infrared image pixels. Backside and frontside reflectors may be incorporated into the infrared pixels to increase effective thicknesses of photosensitive regions within the pixels. In other words, light incident on each pixel may be reflected and traverse the photosensitive region multiple times, thereby allowing silicon in the photosensitive region to absorb infrared light more efficiently. The backside reflector may be interposed between the silicon and a microlens, which may have a toroidal shape to direct light around the backside reflector. If desired, the toroidal lens may have a concave opening. Alternatively, the backside reflector may be ring-shaped, and a spherical microlens may focus light through a center portion of the reflector. A top surface of the silicon layer may be curved to focus light toward the center of the photosensitive region and improve pixel efficiency.

Abstract: An image sensor may be provided with an array of imaging pixels. A color filter array may be formed over photosensitive elements in the pixel array. The color filter array may include color filter elements of different sizes. The color filter array may include color filter elements of at least three different sizes. The color filter array may include color filter elements of only two different sizes. Each color filter element by be square, octagonal, or rectangular. Microlenses of different sizes may also be formed on top of the color filter elements of different sizes. Forming color filter elements with different sizes may help skew the quantum efficiency for light at particular wavelengths of interest so that smaller pixel sizes can be used without suffering from diffraction limits.