Compact optical system and packaging for head mounted display

• US 20050219152A1
• Filed: 01/26/2004
• Published: 10/06/2005
• Est. Priority Date: 07/27/2000
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Olyha, Robert S. Jr., Dove, Derek B., Powell, Carl G., Lovas, Istvan, Budd, Russell A.
• Granted Patent: US 8,289,231 B2
• Time in Patent Office: Days
• US Class Current: 345/8
• CPC Class Codes: G02B 2027/0132 comprising binocular systems
• CPC Class Codes: G02B 2027/0178 Eyeglass type eyeglass details G02C
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 27/0176 characterised by mechanical features
• CPC Class Codes: G02B 5/30 Polarising elements light-modulating devices with active elements G02F1/00

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.

Claims

1. 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;

an optical system mounting structure for supporting the optical system within the field of view of an eye of the user;

a housing to substantially contain at least the optical system; and

a light shield, the light shield being integrated with the housing and positioned with respect to the optical system such that, in an open position, the image signal is viewed by the user with background light entering the optical system, and in a closed position, the image signal is viewed by the user with background light at least partially blocked from entering the optical system.

2. The head mounted virtual image display unit of claim 1, wherein the light shield is slidably integrated in the optical system housing such that the light shield may be slid between the open position and the closed position.

3. The head mounted virtual image display unit of claim 1, wherein the light shield is one of opaque, partially opaque, colored and polarized.