BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention is related to a touch device, particularly to a spatial image display touch device that mitigates the problem of ghost images.

2. Description of the Related Art

Spatial images can be generated by holographic projection technology which allows users to see 3D images projected to the air. The spatial images are usually applied for 3D demonstration.

In Taiwan patent no. 1654445, a spatial image display device with touch function is disclosed. With reference toFIG. 6, a display80is disposed beside and inclined relative to an imaging element70in a casing (not shown). When the display generates an image (as indicated by image light L1), the image light L1is incident on one side of the imaging element70and then reflected by the imaging element70to produce a floating image90visible at another side of the imaging element70.

However, the image light L1from the display80may further directly pass through the imaging element70and be seen as indicated by L2. When an observer looks at the display80through a window of the casing, the appearance of the display80is visible to cause a problem of poor visual sensation.

With further reference toFIG. 7, ghost images91next to the floating image90may also occur and overlap the floating image91. The overlap problem will affect and blur the appearance of the floating image90.

SUMMARY OF THE INVENTION

An objective of the present invention is to provide a spatial image display touch device that uses an optical film to eliminate the ghost images and avoid the problem that the user may directly observe the appearance of the display.

To achieve the objective, the spatial image display includes:

a housing defining a space therein and having a display window formed through a surface of the housing;

an imaging element retained in the space of the housing and attached to the display window, the imaging element comprising a substrate having a plurality of openings disposed in a matrix on the substrate, with each opening provided with a dihedral corner reflector consisting of a first reflecting element and a second reflecting element respectively arranged on two adjacent side surfaces of the opening, wherein the first reflecting element and the second reflecting element face toward a first direction and a second direction respectively;

a display mounted in the space of the housing and being inclined relative to the imaging element at an angle, the display having a display surface facing toward the imaging element and configured to display an image light, the image light passing through the imaging element to form a spatial image at a positon being plane-symmetric to the imaging element;

an optical film attached on the display surface of the display and being composed of a plurality of micro grids arranged in a matrix; and a sensor unit mounted in the space of the housing and emitting a sensing light toward the spatial image, wherein the sensing light overlaps a virtual plane where the spatial image is displayed to form a sensing plane; wherein the sensor unit is configured to detect position data of an object in the sensing plane.

By providing the optical film on the display, oblique light from the display can be filtered out by the optical film. Only the image light exiting from the optical film in a specific light-exit angle range can pass through the imaging element to produce a spatial image. Therefore, the ghost images resulted from oblique light of the display is avoided and the appearance of the display is invisible.

Other objectives, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

