After announcing Glass Enterprise Edition 2, Google now patents holographic smart glasses

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Google Glass was released to consumers in 2013 for nearly $1500.

In 2014, the Google Glass team exited Google X and started reporting to Nest founder, Tony Fadell.

In 2015, the production of Google Glass was stopped but the company insisted that it was committed to launching smart glasses to consumers in a different form.

Google announced Glass Enterprise Edition in 2017 and Glass Enterprise Edition 2 in May 2019.

On July 9th, The United States Patent & Trademark Office granted a patent to Google that relates to holographic smart glasses.

Google notes in its patent that, “An average human eye can accommodate its focus within an object distance range of 7 cm to infinity–an average human eye, in other words, has difficulty focusing well on objects less than 7 cm away. Ideally, the object distance ranges from a couple of meters to infinity to prevent eye strain during prolonged viewing.

Head mounted displays (HMDs) have thus been traditionally designed to project the image from an electronic display, such as a liquid crystal display (LCD) or an array of light emitting diodes (LED), through a lens and into the eye such that the image of the display is virtually projected at a distance far greater than the physical display distance. This prevents the HMD from being huge and ungainly. 

Using this technique traditional HMD designs involve the use of a display, a collimator, and a method of relaying this collimated image into the eye, such as a waveguide.

Some designs combine the collimator and the relay into one optical component, which can greatly simplify the design. But encapsulation of such designs into an eyeglass lens is often difficult because of size, geometry, and see-through constraints. In the interest of having a discreet HMD design, it would be ideal if an image could be projected into the eye without the use of bulky optics and micro-displays, while at the same time being see through and able to be encapsulated in the lens.”

Google’s holographic smart glasses

Google’s figure 1A illustrates an embodiment of a near-eye display (Google smart glasses) #100. Display #100 includes a holographic film #102 having a reflective hologram #104 recorded therein.

Polarizer #106 is positioned on a surface of holographic film #102, and a dynamic mask #108 is positioned on polarizer #106 so the polarizer is sandwiched between the dynamic mask and the holographic film.

The dynamic mask is a mask that can let ambient light pass through unimpeded while dynamically changing the masking of reflective hologram #104 with respect to light incident from light source #112, for instance by selectively darkening or lightening elements within the dynamic mask such as pixels #109, to selectively and dynamically shield parts of reflective hologram #104 from incident light.

In other words, dynamic mask #108 spatially modulates light originating from light source #112 before it is reflected by reflective hologram #104. But, as described below, it does not spatially modulate ambient light that travels from the outside scene through the near-eye display to the eye. 

A transparent spacer #110 is positioned on dynamic mask #108 so that dynamic mask #108 is sandwiched between spacer #110 and polarizer #106. Light source #112 is positioned on spacer #110 and oriented to direct light toward reflective hologram #104 so that light emitted by light source #112 will be incident on reflective hologram #104 after passing through other elements such as spacer #110, dynamic mask #108, and polarizers #114 and #106.

An additional polarizer #114 is sandwiched between spacer #110 and light source #112 so that light emitted by light source #112 can be immediately polarized upon emission. 

Google’s figure 5 illustrates an embodiment of a near eye display (Google smart glasses) #500. Display #500 is similar in most respects to display #100. The primary difference between displays #100 and #500 is that near eye display #500 omits dynamic mask #108 and includes a static holographic image #502.

Static mask #502 can be patterned directly into reflective hologram #104, for instance by appropriately masking one of the recording beam during recording of reflective hologram #104 in holographic film #102 (see figure 1A).

Masked areas of reflective hologram #104 do not reflect light, but instead let it pass through. This effectively superimposes the masked image onto the light that is reflected back toward pupil #117. 

This patent was initially filed in June 2015.

We have to wait and see if Google incorporates this invention into its smart glasses.

Let us know your thoughts in the comments section.

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