The U.S. Patent and Trademark Office officially published a series of 82 newly granted patents for Apple Inc. today. In this particular report we cover Apple's patent relating to the use of photonic crystal material that could be used in future iPhone case, Apple Watch Bands, clothing and more. The material changes color when users touch or press on the material.  

Photonic crystals are periodic microstructures that affect the motion of photons that are incident upon the photonic crystals in a way that causes visual effects. These structures manipulate specific wavelengths of light, resulting in a visually varied or patterns of color. Unlike colored objects that contain chemical substances that reflect and absorb certain wavelengths of light to give the object a particular color, photonic crystals reflect color by its physical microstructures, and are therefore said to reflect color by "structural coloration."

Examples of photonic crystal structures in nature include some butterfly wings that are brilliant iridescent blue due to microstructures within the butterfly wing. Photonic crystals can also be fabricated using stacks of dielectric layers of material or by forming two-dimensional patterns within a substrate. For example, two materials having different refractive indices arranged in very closely packed array patterns can create such photonic crystal effects. However, fabricated photonic crystals have fixed microstructures, and therefore have fixed responses to incident light and therefore have corresponding fixed colors.

Apple's granted patent relates to photonic crystal structures capable of changing color in response to pressure, bending or other types of strain or stress. The systems and methods described can be used in the manufacture of consumer products, such as electronic products and electronic product accessories.

The photonic crystals include periodic microstructures formed within a deformable material such that when a compressive or tensile stress is applied to the photonic crystals, dimensional changes in the microstructures cause an apparent color shift. As used herein, the term "microstructure" is used to describe a structure of very small size, such as structures having dimensions on the scale of nanometers or micrometers. The photonic crystals can be incorporated into base materials for a number of applications, such as casings and enclosures for consumer products, fabrics for clothing, and thin films for application onto windows or display screens. The photonic crystals can be used for purely cosmetic purposes with dynamic color changes providing unusual visual effects, or they can provide a functional purpose, such as acting as visual sensors.

In some embodiments, the photonic crystals include particles of a first material embedded within a matrix of a second material, where the first material has a different index of refraction than the second material. For example, the particles can be composed of polymer, glass or ceramic, which are embedded within a matrix of polymer. Any suitable polymer material can be used. For example, polymer can be an organic polymer, a non-organic polymer or a combination thereof. In some embodiments, the polymer is a silicone or silicon-based polymer. The particles can have substantially the same diameter such that when the particles are closely packed within the second material, a periodic structure capable of producing photonic crystal colorization arises.

In some embodiments, the microstructures are voids formed within a flexible material using, for example, a laser. The voids can have any suitable shape and arrangement capable of forming the periodic microstructures of a photonic crystal. In some cases, the voids are in the shape of holes or channels within the flexible material. In some embodiments, the voids are filled with air, while in other embodiments the voids are filled with a liquid. In some embodiments, a composite material that includes multiple layers of photonic crystal structures is formed.

Beyond an iPhone case such as illustrated in patent FIGS. 9A&B below, other products could include wearable items, such as clothing (e.g., shirts or portions of shirts) and accessories such as wristbands, headbands, jewelry, gloves, belts, watches, ties, scarves, bags and backpacks etc.

In some embodiments, photonic crystal structures can deform in response to heating or cooling and change colors of red, green, blue and more.

In some embodiments, photonic crystal structure #100 flexes in response to a force that is exerted on its surface, such as a pressing force from a person's finger. FIG. 3 shows a perspective view of a portion of photonic crystal structure after a force has been applied to its surface #302.

Lastly, Apple's patent FIG. 7 above illustrates a flowchart indicating a process for forming flexible photonic crystal structures in accordance with some embodiments.

Apple's granted patent 10,690,946 was originally filed in Q3 2016 and published today by the US Patent and Trademark Office. Apple's inventor is listed as James Wilson, Apple's Senior Product Design Engineer, Materials.