Browse Prior Art Database

Display Illumination and Projection

IP.com Disclosure Number: IPCOM000062689D
Original Publication Date: 1986-Dec-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Seaton, RJ: AUTHOR

Abstract

An illumination and projection system is disclosed for a non-transparent, specular reflecting display device, such as an electrochromic display device. The display device is mounted off-center and normal with respect to a lens axis by at least half of the display height but within the area covered by the lens. A light source provides a beam normal to the axis to illuminate the device at the critical reflective angle via an angled mirror. Height reflected by the device is projected by the lens. When attempting to project an image of a non-transparent data medium, such as the electrochromic display device, a conflict occurs between the path for the light to illuminate the display and the path for the projected image.

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Display Illumination and Projection

An illumination and projection system is disclosed for a non-transparent, specular reflecting display device, such as an electrochromic display device. The display device is mounted off-center and normal with respect to a lens axis by at least half of the display height but within the area covered by the lens. A light source provides a beam normal to the axis to illuminate the device at the critical reflective angle via an angled mirror. Height reflected by the device is projected by the lens. When attempting to project an image of a non-transparent data medium, such as the electrochromic display device, a conflict occurs between the path for the light to illuminate the display and the path for the projected image. This display and projection system makes use of a conventional front surface mirror with a conventional lens of the type used in 35 mm single lens reflex (SLR) cameras. The layout and idealized ray paths are shown in the drawing. Key parameters are: 1.The display element must have a specular reflective form. 2. The display element is mounted off the lens axis downwards by at least half the display height, without

the display going outside the area covered by the lens.

This is normally a 43.3 mm diameter circle for 35 mm

camera lenses. 3. The edge of the mirror (ME in the drawing) is on

the center line of the display, and close to the rear

element of the projection lens and angled with respect

to the lens axis to prov...