US 6,061,177 A · Integrated computer display and graphical input apparatus and method

Abstract

A touch screen input device and method for use with a rear-mounted video output projection system incorporates a transparent sheet preferably having substantially parallel top and bottom surfaces as the touch screen panel. A rear-mounted light source projects light onto the rear surface of the touch screen panel, on which a diffusing surface is imposed, with the result that some of the light from the light source is totally internally reflected within the touch screen panel and is imaged by a rear-mounted video camera. When the front surface of the touch screen panel is touched by a finger or rubbery object, total internal reflection is interrupted and the video camera images the touch as a dark spot. Because the touch screen panel is a sheet having substantially parallel surfaces, the video output system with which the input device is designed to be used is a projection system, and the technology used to detect touches is optical imaging, the touch screen input device can be readily scaled up to desktop or large work-surface sizes. The touch screen input device operates equally well in an environment with any level of ambient light or no ambient light and can simultaneously detect multiple touches. The touch screen input device remains operative while books or other common desktop objects are left resting on portions of the touch screen panel.

Claims32

Dependent claims

A touch screen input device, which comprises:

a transparent sheet having a first surface and a second surface, the transparent sheet having an index of refraction greater than that of air, and the first surface being a smooth surface defining a touch surface of the touch screen input device;
a diffusing surface imposed on the second surface of the transparent sheet;
a light source positioned in proximity to the second surface so that the second surface is closer than the first surface to the light source, and positioned to project light onto the diffusing surface of the transparent sheet, and so that when light is projected onto the diffusing surface some light refracts as said some light passes through the diffusing surface and reflects within the transparent sheet when said some light reaches the first surface;
and
a camera positioned in proximity to the second surface so that the second surface is closer than the first surface to the camera, and positioned to image light emanating from the second surface of the transparent sheet;
whereby reflection of light within the transparent sheet is interrupted where the touch surface is being touched and light emanating from the second surface is thereby reduced.

3 more elements

A method for providing a reference light level to an imaging means in a touch screen input device, the touch screen input device having a screen panel with substantially parallel top and bottom surfaces, the top surface forming a touch surface having central areas and perimeter areas, and the bottom surface forming a diffusing surface having central areas and perimeter areas that correspond to the central areas and perimeter areas of the touch surface;

a light source for projecting light onto the diffusing surface;
the imaging means for imaging light from the bottom surface;
and an opaque covering positioned on some portion of the perimeter areas of the touch surface such that ambient light does not transmit through the opaque covering, the method comprising the steps of:
projecting light onto the perimeter areas of the diffusing surface of the screen panel corresponding to the portion of the perimeter areas of the touch surface on which the opaque covering is positioned using the light source, such that some of the projected light passes through the diffusing surface and is totally internally reflected within the screen panel and some of the projected light reflects directly off the perimeter areas of the diffusing surface corresponding to the portion of the perimeter areas of the touch surface on which the opaque covering is positioned;
and
imaging the projected light that is totally internally reflected within the screen panel and that passes back through the perimeter areas of the diffusing surface corresponding to the portion of the perimeter areas of the touch surface on which the opaque covering is positioned and the projected light that reflects directly off the perimeter areas of the diffusing surface corresponding to the portion of the perimeter areas of the touch surface on which the opaque covering is positioned with the imaging means, such that the imaged light from the perimeter areas of the diffusing surface corresponding to the portion of the perimeter areas of the touch surface on which the opaque covering is positioned provides a reference light level for comparison with imaged light from the central areas of the diffusing surface.

3 more elements

Dependencies are inferred from the claim text.

Integrated computer display and graphical input apparatus and method

Life of this patent

Integrated computer display and graphical input apparatus and method

Life of this patent

Abstract

Claims32