TRANSPARENT CAPACITIVE TOUCH PANEL

The capacitive touch panel includes a transparent substrate, a first transparent conductive layer, a first transparent insulative layer, a second transparent conductive layer, and a second transparent insulative layer. Each transparent conductive layer has a plurality of capacitive sensor rows. Every adjacent two of the capacitive sensor rows are formed with a gap to be insulated. The transparent insulative layers have a refractive index equal to or greater than that of the transparent conductive layers and fill the gaps. Each of the insulative layers is composed of a plurality of insulative coatings, and each coating is less than 100 nm in thickness.

DETAILED DESCRIPTION OF THE INVENTION

Please refer toFIGS. 1-3. The invention forms a fundamental insulative layer2, an X-axis conductive layer3, an intermediate insulative layer4, a Y-axis transparent conductive layer5, and a protective insulative layer6in sequence on a substrate1.

The substrate1may use soda lime glass with a refractive index (RI) of about 1.5.

The X-axis and Y-axis conductive layers3,5may use indium tin oxide (ITO). There are transparent X-axis capacitive sensor rows31at a constant interval along X-axis on the X-axis conductive layer3. A gap33is remained between every two adjacent X-axis capacitive sensor rows31. The gaps33divide the X-axis capacitive sensor rows31to be insulated. Ends of the X-axis capacitive sensor rows31are electrically separately connected with signal wires32with signal output ends34. Similarly, there are transparent Y-axis capacitive sensor rows51at a constant interval along Y-axis on the Y-axis conductive layer5. A gap53is remained between every two adjacent Y-axis capacitive sensor rows51. The gaps53divide the Y-axis capacitive sensor rows51to be insulated. Ends of the Y-axis capacitive sensor rows51are electrically separately connected with signal wires52with signal output ends54.

The insulative layers2,4,6use a material with a refraction index (RI) equal to or greater than that of the conductive layers3,5, such as a polymeric material containing silicon dioxide (SiO2, RI≈1.6), aluminum oxide (Al2O3, RI≈1.8) or niobium pentoxide (Nb2O5, RI≈2.3). Generally speaking, a desired thickness of each of the insulative layers2,4,6is between 10 nm and 1000 nm. In a preferred embodiment, each of the insulative layers2,4,6is composed of multiple coatings, the dry coating method, such as the vacuum coating approach, is utilized to form multiple insulative coatings on the conductive layers3,5. Each single coating had better be below 100 nm to avoid internal stress due to excessive thickness. As shown inFIG. 4, each of the insulative layers2,4,6is composed of multiple coatings9. Additionally, each of the insulative layers2,4,6may use two or more different coatings in material to obtain an insulative layer with a greater thickness, better insulation ability and a suitable RI for matching the conductive layer3,5. Preferably, the coatings9are odd in number, for example three or five, and the odd coatings are made of the same material to avoid deformation resulting from uneven stress.

The fundamental insulative layer2is completely superposed on the substrate1. The intermediate insulative layer4is disposed on the X-axis conductive layer3and the gaps33are filled with an insulative material. The protective insulative layer6is disposed on the Y-axis conductive layer5and the gaps53are filled with an insulative material. By selecting the insulative material with an RI matching with the conductive layers3,5and filling the gaps33,53with the insulative material, evenness of RI and optical properties of the conductive layers3,5can be effectively enhanced.

FIG. 5shows another embodiment of the invention. This embodiment is to directly form the X-axis conductive layer3on the substrate1and then form the intermediate insulative layer4, Y-axis conductive layer5and protective insulative layer6in the order as abovementioned. In other words, the first transparent insulative layer of the above embodiment may be selectively omitted to simplify the manufacturing process and reduce the costs.

The foregoing description is only the most preferred embodiments of the present invention, but the structural feature of the present invention is not limited thereto. It would be appreciated by those skilled in the art that variations or modifications may be contemplated readily without departing from the following claims of the invention.