Apple may have found a way to add a camera with a true optical zoom into their next or next next iPhone and iPad.
The new set-up is described in a patent application “Digital camera with light splitter” and shows a camera module with optical zoom lens, that can fit into a portable device that is 6 to 13mm thick and 18 to 32mm wide. Which is well within the 123.8×58.6×7.6mm dimensions of iPhone 5.
The new camera works like this:
Behind the first plano-concave lens (22 in the picture below) that captures the incoming light, the imaging system will have a deflector which, instead of letting the light to pass through straight, will turn it at a 90 degree angle along the x-axis (width) of the device. The deflector (20) may be an angled mirror or other optical element that can perform a similar function. This arrangement allows Apple to place other camera components along the full width of the device, without worrying it’ll become too thick. And gives enough space to install a zoom lens with movable lens elements (21).
Another interesting part of the new Apple camera is the light splitter cube (2 in the picture above, see details in the picture below). Its purpose is to split the incoming light into three separate color components (e.g. Red, Green, Blue) and send each color out through one of cube’s three sides.
Because then, to capture that light of one known color and convert it into electronic signals which can be processed, you can use image sensors that are:
“… clear pixel array sensors that have no color filter array or color separation capabilities, making them relatively inexpensive yet more accurate (due to no color interpolation or demosaicing required). In such a color splitting architecture, the amount of light incident on each pixel is about three times greater than in a conventional Bayer-pattern color filter array (CFA) sensor. Also, the color splitting cube may essentially avoid the color-crosstalk that is typical of traditional Bayer-pattern CFA sensors.
The color splitter cube is made of 4 identically sized optically transparent polyhedrons. The sides of polyhedrons are covered by optical coating consisting of one or more layers of optical material. Adjoining faces of the polyhedrons are optically bonded to each other with no air gap, and tuned only to one color of light (red, green or blue), while letting the other wavelengths pass through. This way, only a light of one color gets out of one side of the light splitting cube, and is sent to the image sensor and further processing.
Apple has already tested such a camera module, and claims that:
“… simulation of such an optical system has shown that, where the light splitter 2 is a cube of 3.5 mm.times.3.5 mm.times.3.5 mm, the x-length of the combination may be in the range 18 mm-32 mm, while at the same time being able to achieve 22.degree.-66.degree. angle of view. This is a particularly compact arrangement that is suitable for being integrated within portable wireless communications devices such as tablet computers and smart phones in which the outer housing of the communications device has a z-height or thickness within the range of 6 mm-13 mm.”
This patent application has been filed in September 2011, so Apple has been working on the new camera with optical zoom for a while now. And I am sure there are still quite a few things to iron out, before its ready for mass production.
But this technology feels to be much close to real life implementation, than most of the stuff I’ve seen in Apple’s patents.