The patent filing, titled "Display resolution increase with mechanical actuation," describes a mechanism that can bump the perceived resolution of a digital display without actually increasing the number or density of pixels, a method Apple calls "pixel multiplication."
While the idea of a wearable HUD is intriguing, existing technologies don't necessarily provide for a user experience consumers have come to expect from portable electronics. Perhaps most noticeable is the quality of a device's screen such as the high-resolution Retina displays used in Apple's iPhone, iPad and now MacBook Pro product lines. Despite its already high pixel density, even a Retina display would look unacceptable at extremely close viewing distances and Thursday's patent filing aims to solve this problem.
Illustration from Apple's patent filing. | Source: USPTO
In the filing's background, Apple notes manufacturing costs and energy concerns are the two main hurdles in building a high-resolution portable display:
These factors may take greater consideration in portable displays devices where batteries provide the power and space/weight may be limited. In particular, a portable heads-up display may be size and weight constrained such that addition of physical pixels may not be practical. Conventionally, fewer physical pixels may mean lower cost to manufacture, lower weight, smaller
size, but also lower resolution.Apple proposes a mechanism that can shift a specially-synchronized digital display assembly fast enough to create a higher perceived resolution without upping the number of physical pixels.
The filing explains:
In particular, an actuator is implemented to shift physical pixels between multiple positions within a prescribed time period so that a single physical pixel appears to a viewer as multiple pixels. Hence, the pixel density is effectively multiplied by the number of positions to which the physical pixels may be displayed.
Supporting claims include methods for storing and displaying image data, feeding said data to corresponding pixels at the correct time during actuation and using lens and mirror configurations to achieve optimal output.
Display actuation and data synchronization results in pixel multiplication. | Source: USPTO
Apple offers two separate methods by which pixel multiplication can be achieved. The first solution, described above, actuates the display itself while a second method involves adding an array of optics between the display and the user's eye. This lens and mirror assembly can be shifted in synchronization with physical pixel output to "give the appearance of multiple pixels per physical pixel."
Shifting of a lens array can alternately be used for pixel multiplication.
The filing notes the cost of actuators and circuitry should "generally be much less than the cost of physically representing the pixels independently, especially when the single physical pixel is scaled to represent four or more pixels."
It is unlikely that the technology will be used in a commercial application any time soon if at all, however the filing signals Apple's intent to remain a tech industry innovator.