It has been rumored for a long time that Apple is developing some form of head-mounted display, possibly in the form of VR or AR head display. There is also a product called "Apple Glass", which is considered as smart glasses with AR function. In a pair of patents granted to Apple by the U.S. Patent and Trademark Office on Tuesday, people can see that Apple is studying display elements in order to make the rumored devices achieve the best results in the competition.
The details of the new patent show that Apple AR head display or "Apple Glass" devices may use a movable display screen to compensate for motion blur, and Fresnel lens can help users reduce the weight of the head display. Among them, the first patent is called "Motion blur compensation through display driver", which deals with the motion blur problem in an unusual way.
although motion blur can usually be alleviated by reducing the persistence of pixels on the display, this may not be what we want because it reduces the perceived brightness of the display itself. Ideally, the display screen needs to keep the pixel illumination time long enough to make the user feel bright, while reducing the illumination time will make the display screen dark. In the patent, Apple suggested that the head-mounted display can include a sensor to detect the movement of the device to determine an inter-frame movement, such as direction and speed, which is used as a starting point to reduce the blur caused by the movement.
when motion is detected, an actuator can move the screen to counteract any motion blur. The motion data is used to adjust the actuator connected to the display to make it move against the position change between frames. By moving the screen, it counteracts the influence of the motion of the whole device and can reduce the motion blur.
The second patent is called "Head mounted display device with Fresnel lens", and Apple provides a display system, which may create a light head display for users. Usually, VR head displays rely on a series of lenses, so that users can clearly see the screen close to their eyes. With a lens, the screen looks like it is in focus and seems far away, but this may increase the weight of the head-up display design. Fresnel lens is a kind of lens with wedge, groove and ring to adjust the passage of light in different areas. This is similar to the concept that a lighthouse uses a Fresnel lens to concentrate light on the sea instead of illuminating the whole area.
In Apple's patent, the lens consists of an arc convex surface pointing to the display screen, and is equipped with a slope surface and a draft surface, so that users can see the screen. The screen itself can be flat or curved. If necessary, the lens structure can make use of the curvature of the screen. In order to reduce light scattering, opaque shielding materials can be coated on the draft surface, or concentric rings of similar materials can be arranged on the transparent substrate near the draft surface.
In such a system, a pair of Fresnel lenses can be used, one of which adjusts the light from the display to a specific distribution pattern. The second one can collect the light irradiated in this mode and aim it at the user's vision. By using Fresnel lens, Apple can build a system that uses a small number of lenses to work together, reducing the amount of glass used, and in turn reducing the weight of the head display itself.