Compact optical system and packaging for head mounted display
First Claim
1. A compact optical system for directing an image signal for viewing by a user, the image signal being generated in accordance with a microdisplay, the system comprising:
- a beam splitting prism positioned proximate to the microdisplay;
a field lens positioned between the beam splitting prism and the microdisplay;
a negative lens positioned between the field lens and the beam splitting prism;
a reflective lens positioned proximate to the beam splitting prism, on a side of the beam splitting prism opposite the microdisplay; and
a quarter wave plate positioned between the reflective lens and the beam splitting prism;
wherein the beam splitting prism, the field lens, the negative lens, the reflective lens and the quarter wave plate are arranged such that the image signal, linearly polarized in accordance with the microdisplay;
(a) passes through the field lens and the negative lens;
(b) enters the beam splitting prism substantially passing through a polarizing surface of the beam splitting prism;
(c) passes through the quarter wave plate becoming circularly polarized;
(d) reflects at a surface of the reflective lens back toward the quarter wave plate passing through the quarter wave plate a second time becoming linearly polarized with a polarization direction rotated by 90 degrees with respect to an original linear polarization direction associated with the image signal; and
(e) reenters the beam splitting prism substantially reflecting at the polarizing surface of the beam splitting prism and exits the beam splitting prism for viewing by the user.
1 Assignment
0 Petitions
Accused Products
Abstract
A head mounted virtual image display unit is provided which is compact in size and weight, and incorporates a high performance optical system offering a clear see-through capability. A sliding light shield may be incorporated for those instances when see-through capability is not desired. A focus adjustment may be incorporated to permit the focusing of the image, for example, at a distance of approximately 18 inches to infinity. An adjustable headband may be incorporated that adapts to fit the users head. A flexible boom structure may be incorporated to facilitate fine positional adjustment of the optical assembly. A slider and ball joint mechanism may also be incorporated to facilitate positional adjustment of the optical assembly. A built-in microphone may be incorporated to enable speech input by the user. The head mounted virtual image display unit may be used comfortably in conjunction with eye or safety glasses, and provides a useful image to the user without blocking his view of the surrounding environment. The unit is designed to have a pleasing appearance so as to greatly enhance user acceptability.
359 Citations
24 Claims
-
1. A compact optical system for directing an image signal for viewing by a user, the image signal being generated in accordance with a microdisplay, the system comprising:
-
a beam splitting prism positioned proximate to the microdisplay;
a field lens positioned between the beam splitting prism and the microdisplay;
a negative lens positioned between the field lens and the beam splitting prism;
a reflective lens positioned proximate to the beam splitting prism, on a side of the beam splitting prism opposite the microdisplay; and
a quarter wave plate positioned between the reflective lens and the beam splitting prism;
wherein the beam splitting prism, the field lens, the negative lens, the reflective lens and the quarter wave plate are arranged such that the image signal, linearly polarized in accordance with the microdisplay;
(a) passes through the field lens and the negative lens;
(b) enters the beam splitting prism substantially passing through a polarizing surface of the beam splitting prism;
(c) passes through the quarter wave plate becoming circularly polarized;
(d) reflects at a surface of the reflective lens back toward the quarter wave plate passing through the quarter wave plate a second time becoming linearly polarized with a polarization direction rotated by 90 degrees with respect to an original linear polarization direction associated with the image signal; and
(e) reenters the beam splitting prism substantially reflecting at the polarizing surface of the beam splitting prism and exits the beam splitting prism for viewing by the user.- View Dependent Claims (2, 3, 4, 5, 6, 7)
-
-
8. A head mounted virtual image display unit, the unit comprising:
-
a microdisplay;
an optical system for directing an image signal for viewing by a user, the image signal being generated in accordance with the microdisplay; and
an optical system mounting structure for supporting the optical system within the field of view of an eye of the user;
wherein the optical system includes;
a beam splitting prism positioned proximate to the microdisplay;
a field lens positioned between the beam splitting prism and the microdisplay;
a negative lens positioned between the field lens and the beam splitting prism;
a reflective lens positioned proximate to the-beam splitting prism, on a side of the beam splitting prism opposite the microdisplay; and
a quarter wave plate positioned between the reflective lens and the beam splitting prism; and
further wherein the beam splitting prism, the field lens, the negative lens, the reflective lens and the quarter wave plate are arranged such that the image signal, linearly polarized in accordance with the microdisplay;
(a) passes through the field lens and the negative lens;
(b) enters the beam splitting prism substantially passing through a polarizing surface of the beam splitting prism;
(c) passes through the quarter wave plate becoming circularly polarized;
(d) reflects at a surface of the reflective lens back toward the quarter wave plate passing through the quarter wave plate a second time becoming linearly polarized with a polarization direction rotated by 90 degrees with respect to an original linear polarization direction associated with the image signal; and
(e) reenters the beam splitting prism substantially reflecting at the polarizing surface of the beam splitting prism and exits the beam splitting prism for viewing by the user.- View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
-
-
24. A portable computer system, comprising:
-
(a) a head mounted virtual image display unit, the unit including;
a microdisplay;
an optical system for directing an image signal for viewing by a user, the, image signal being generated in accordance with the microdisplay, the optical system including;
a beam splitting prism positioned proximate to the microdisplay;
a field lens positioned between the beam splitting prism and the microdisplay;
a negative lens positioned between the field lens and the beam splitting prism;
a reflective lens positioned proximate to the beam splitting prism, on a side of the beam splitting prism opposite the microdisplay; and
a quarter wave plate positioned between the reflective lens and the beam splitting prism;
wherein the beam splitting prism, the field lens, the negative lens, the reflective lens and the quarter wave plate are arranged such that the image signal, linearly polarized in accordance with the microdisplay;
(a) passes through the field lens and the negative lens;
(b) enters the beam splitting prism substantially passing through a polarizing surface of the beam splitting prism;
(c) passes through the quarter wave plate becoming circularly polarized;
(d) reflects at a surface of the reflective lens back toward the quarter wave plate passing through the quarter wave plate a second time becoming linearly polarized with a polarization direction rotated by 90 degrees with respect to an original linear polarization direction associated with the image signal; and
(e) reenters the beam splitting prism substantially reflecting at the polarizing surface of the beam splitting prism and exits the beam splitting prism for viewing by the user; and
an optical system mounting structure for supporting the optical system and microdisplay within the field of view of an eye of the user; and
(b) a computer-based device, coupled to the head mounted virtual image display unit, for generating and providing an electrical signal to the microdisplay for use in generating the image signal to be viewed by the user.
-
Specification