Touch device

Abstract

An assembly for holding and controlling curvature of a glass plate for an optical touch sensitive system is described. The assembly comprising a first frame element extending in a first plane and configured to extend at least partially around a panel; at least one second frame element extending in a second plane and forming a support portion for the plate, and at least one spacing element positioned at least partially between the support portion and the first frame element. The spacing element us configured to control a curvature of the first frame element and wherein the at least one second frame element is configured to engage the plate at the support portion, is attached to the first frame element, and is tiltable, by controlling the curvature of the first frame element with said spacing element, to control a curvature of the plate.

Description

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS[0001]Any and all applications for which a foreign or domestic priority claim is identified in the Application Data Sheet as filed with the present application are hereby incorporated by reference under 37 CFR 1.57.BACKGROUNDField of the Invention[0002]This invention relates in general to the field of optical touch sensitive systems. More particularly, the invention relates to a curved plate and an assembly for holding a plate of the system, such as a glass plate, relative to a panel such that curvature of the plate is controlled. The invention also relates to a method for assembling a plate of an optical touch sensitive system with a panel (such as a display panel) in such a way that curvature is controlled.Background of the Invention[0003]In one category of touch sensitive panels known as above surface optical touch systems and known from e.g. U.S. Pat. No. 4,459,476, a plurality of optical emitters and optical receivers are a...

AI Technical Summary

Benefits of technology

The invention relates to controlling the curvature of a plate used in an optical touch-sensitive system to prevent distortion and improve accuracy. This is achieved by controlling the curvature of the plate during assembly with a panel, which increases the field of view for a detector and reduces the light budget required. The assembly is compact and the curvature can be controlled without touching the center of the plate.

Problems solved by technology

This type of system is only capable of reliably detecting the location of one object (single-touch detection).

Further, the required number of emitters and receivers, and thus cost and complexity, increases rapidly with increasing surface area and / or spatial resolution of the touch panel.

In systems where the light is directed closer to the touch surface, distortions in the plate have a disproportionally large effect on the light signal.

Therefore, glass plates as used in previously known above surface optical touch systems are unsuitable when the light is transmitted closer to the plate, since the accuracy of the system is impaired by the distortions in the plate.

Additionally, a frame for assembly of the plate of the optical touch sensitive system and a panel, such as an LCD panel, may introduce distortion in the form of uncontrolled warpage, i.e. a twist or curve in the plate is introduced even if it is usually flat.

The uncontrolled warpage may even block the light transmitted across the plate.

This is due to uncontrolled twisting of the frame as such when it is attached to the panel.

However, such solutions are unsuitable / insufficient for touch sensitive systems since they typically require bulky frames at the border of the glass and / or pressure points closer to the center of the panel where force may be applied to control the shape of the glass.

These solutions are unsuitable where a minimal / lightweight border bezel is required, and no supporting objects may touch the glass further in than at the borders.

Additionally, pre-bent glass is expensive and fragile to transport.

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