Optical system
Assignee3M Innovative Properties Company
InventorsTimothy L. Wong, Timothy J. Lindquist
Life of this patent
Estimating the term…
Abstract
An optical system (200) that allows a viewer (10) to simultaneously see images created by an electronic display (20) as well as real world objects (30b) includes a reflective polarizer (41) as an image combiner for head-mounted displays and an absorptive polarizer (42) deployed in the same combiner to reduce glare by minimizing ambient reflections from the reflective polarizer. To prevent the absorptive polarizer (42) from blocking linearly polarized light sources from being transmitted through the combiner, a weak absorptive polarizer is provided to allow transmission of polarized sources while still minimizing glare.
Claims15
An optical system for displaying first and second images to a viewer, comprising:
- different first and second displays;
- and
- an optical stack configured to receive:
- a first light ray from the first display and reflect the received first light ray for viewing by the viewer;
- and
- a second light ray, different than the first light ray, from the second display and transmit the received second light ray for viewing by the viewer, wherein, the optical stack comprises:
- a reflective polarizer facing the first display;
- and
- an absorbing polarizer disposed on the reflective polarizer and facing the second display, each of the reflective and absorbing polarizers comprising orthogonal pass and block axes, such that for substantially normally incident light having a wavelength in a range from about 400 nm to about 700 nm:
- the reflective polarizer reflects at least 70% of the incident light polarized along the block axis of the reflective polarizer, and transmits at least 70% of the incident light polarized along the pass axis of the reflective polarizer;
- and
- the absorbing polarizer absorbs at least 50% and at most 85% of the incident light polarized along the block axis of the absorbing polarizer, and transmits at least 70% of the incident light polarized along the pass axis of the absorbing polarizer,
- wherein the block axes of the reflective and absorbing polarizers make an angle with each other between about 5 degrees to about 40 degrees.
A see-through optical system for displaying a virtual image to a viewer, comprising:
- a first display configured to emit a first image having a first polarization state;
- and
- an optical stack curved along two mutually orthogonal directions and configured to receive the emitted first image and reflect the received first image for viewing by the viewer, the viewer observing a magnified virtual image of the first image, the viewer able to receive and see a polarized real-world object in a real-world scene through the optical stack, such that for light having at least one wavelength in a predetermined wavelength range and propagating along a substantially normal incident direction, the optical stack:
- reflects at least 70% of the incident light polarized along the first polarization state;
- and
- absorbs at least 50% and at most 85% of the incident light having an orthogonal second polarization state,
- wherein the polarized real-world object remains viewable by the viewer as the optical stack is continuously rotated at least 180 degrees about light incident on the optical stack from the polarized real-world object.
Dependencies are inferred from the claim text.