BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A to 1B are sectional views schematically showing the high transmittance touch panel according to a first embodiment of the present invention.
FIGS. 2A to FIG. 2R are sectional views schematically showing the high transmittance touch panel according to a second embodiment of the present invention.
FIG. 3 is a sectional view schematically showing the high transmittance touch panel according to one form of a third embodiment of the present invention.
FIG. 6 is a sectional view schematically showing the high transmittance touch panel according to another form of a third embodiment of the present invention.
FIGS. 9A to 9B are sectional views schematically showing the high transmittance touch panel according to a fourth embodiment of the present invention.
FIG. 4, FIG. 7, and FIG. 10 to FIG. 12 are diagrams showing the relationship between the transmittance and the wavelength within the range of visible light in the conventional technologies and the present invention.
FIG. 5, FIG. 8, and FIG. 13 to FIG. 15 are diagrams showing the relationship between the reflectivity and the wavelength within the range of visible light in the conventional technologies and the present invention.
FIG. 16 is a diagram showing the total transmittances of the touch panels of the conventional technologies and the present invention, which are tested with the Haze-Gard Plus hazemeter according to ASTM-D1003.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Refer to FIG. 1A a sectional view schematically showing the high transmittance touch panel according to a first embodiment of the present invention. According to the first embodiment of the present invention, the high transmittance touch panel comprises: a substrate 6 and a first anti-reflection coating structure A. The substrate 6 has a front side 7 and a rear side 12, and the front side 7 is defined to be the side neighboring the user, and the rear side 12 is defined to be the side neighboring the backlight source. The substrate 6 may be made of glass, plastic, or another transparent material. The first anti-reflection coating structure A is a four-layer structure and comprises: a first layer 1, a second layer 2, a third layer 3 and a fourth layer 4, which are disposed sequentially from the front side 7 of the substrate 6. Those layers may be formed with a vacuum coating technology, such as sputtering, evaporation, chemical vapor deposition, or other wet coating technologies.
The first layer 1 is an oxide layer having a refractive index greater than 1.5. In this embodiment, the first layer 1 may be made of niobium pentoxide (Nb2O5). The material of the first layer 1 may also be selected from the group consisting of ITO (Indium Tin Oxide), ATO (Antimony Tin Oxide), niobium oxide, titanium oxide and tantalum oxide, or be a mixture of those oxides.
The second layer 2 is an oxide layer having a refractive index within from 1.3 to 1.5. In this embodiment, the second layer 2 may be made of silicon oxide (SiO2). The material of the second layer 2 may also be selected from the group consisting of porous low-refractive-index material, fluorinated low-refractive-index material and organically modified low-refractive-index material.
The third layer 3 is a transparent conductive layer having a refractive index within from 1.8 to 2.5 and an impedance value within from 200 to 10000 ohm/square. In this embodiment, the third layer 3 is connected with the electrode pattern along the perimeter of the touch panel and is made of ITO with an additive—niobium pentoxide (Nb2O5). The material of the third layer 3 may also be selected from the group consisting of ATO, pure ITO, tin dioxide (SnO2), zinc dioxide (ZnO2), indium oxide (In2O3), or be a mixture of those oxides. Whether to add the abovementioned additive niobium pentoxide (Nb2O5) depends on requirements, and the concentration of the additive is within from 0.1 to 20%.
The fourth layer 4 is a protective layer having a refractive index within from 1.3 to 1.5 and a thickness of at least 0.1 μm. The fourth layer 4 also has a hardness reaching 9H of ASTM-D3363 and passes at least 1000 strokes of the abrasion test according to MIL-C-675C. In this embodiment, the fourth layer 4 may be made of silicon dioxide or organically modified silica.
Thus, according to the first embodiment of the present invention, a four-layer structure of anti-reflection coating layers is coated on the front side 7 of the substrate 6 of the touch panel, and the refractive indexes of those layers are high, low, high, and low (denoted by H, L H, L) sequentially from the layer neighboring the substrate 6. Thereby, the light transmittance of the touch panel of the present invention can reach over 92% according to ASTM-D1003. Further, as the outmost layer of those layers is defined to be a protective layer, the abrasion resistance of the touch panel of the present invention is enhanced. Another preferred embodiment is shown in FIG. 1B. A protective layer 4a is added on the rear side 12 of the substrate 6 to protect the rear side 12. The material of protective layer 4a is the same as the fourth layer 4.
Refer to from FIG. 2A to FIG. 2R sectional views respectively schematically showing five forms of a second embodiment of the present invention. A first form is shown in FIG. 2A. In addition to the abovementioned four-layer anti-reflection coating structure, the front side 7 and the rear side 12 of the substrate 6 are roughened via an acid-dipping method or an acid-etching method in order to obtain an anti-glare effect. This embodiment is not limited to roughening double sides of the substrate 6, and roughening only the user-neighboring front side 7 of the substrate 6 may also work, as shown in FIG. 2C for a second form. A third form is shown in FIG. 2F, multiple particles 13 with the refractive indexes thereof within from 1.3 to 2.5 and the diameters thereof within from 0.01 to 4 μm may be added into the outmost layer (the fourth layer 4) to obtain an anti-glare effect. Further, as shown in FIG. 2J for a fourth form. A fifth layer 5 (an anti-glare layer) may be coated on the fourth layer 4 via a spraying method to roughen the surface of the touch panel with the roughness thereof within from 0.01 to 4 μm; thus, an anti-glare effect is obtained. Another preferred embodiment structure is to form an anti-glare layer 5a on the rear side 12 of the substrate 6 to as shown in FIG. 2L. Furthermore, in this embodiment, it is not necessary after four layers have been formed that the abovementioned fifth layer 5 is to be formed. As shown in FIG. 2N for a fifth form, the fifth layer 5 may be formed on the third layer 3 with a spraying method, and then, the fourth layer 4 is formed on the fifth layer 5.
Another preferred embodiment is based on the structures of FIGS. 2A, 2C, 2F, 2J, and 2N. A protective layer 4a is coated on the rear side 12 having a rough surface as shown in FIGS. 2B, 2D, 2G, 2K, and 20. In FIG. 2G, the protective layer 4a is further added a plurality of particles 13. The particles 13 with the refractive indexes within from 1.3 to 2.5 obtain a better anti-glare effect.
Refer to FIG. 3 for one form of a third embodiment of the present invention. In this embodiment, the rear side 12 of the substrate 6 further has a second anti-reflection coating structure B with mirror structure. The second anti-reflection coating structure B further comprises: an eighth layer 8, a ninth layer 9 and a tenth layer 10, which are disposed sequentially from the rear side 12 of the substrate 6. Those layers may also be formed with a vacuum coating technology, such as sputtering, evaporation, chemical vapor deposition, or other wet coating technologies.
The refractive index of the eighth layer 8 is identical to that of the first layer 1, and the refractive index of the ninth layer 9 is identical to that of the second layer 2. The refractive index of the tenth layer 10 is also identical to that of the third layer 3 and has an impedance value within 10 to 105 ohm/square and connects with the conductor along the perimeter of the touch panel. In this embodiment, the tenth layer 10 may be an ITO layer and has an impedance value within from 100 to 700 ohm/square.
Thus, according to the third embodiment of the present invention, a three-layer structure of anti-reflection coating layers is coated on the rear side 12 of the substrate 6, and the refractive indexes of those layers are high, low, and high (denoted by H, L H) sequentially from the layer neighboring the substrate 6. Thereby, the light reflection of the touch panel can be further reduced, and the light transmittance of the touch panel can be further increased. Furthermore, the tenth layer 10 also has an anti-EMI (ElectroMagnetic Interference) function.
Refer to FIG. 4 and FIG. 5 for the transmittance and the reflectivity of the anti-reflection coating structure of double ITO layers plus one protective layer mentioned above. For the wavelengths within from 431 to 692 nm, the corresponding transmittances are all over 92%. For the wavelengths within from 440 to 700 nm, the corresponding reflectivities are all below 10%.
Refer to FIG. 6 for another form of the third embodiment of the present invention. In this form, a fifth layer 5 (an anti-glare layer) is also coated on the fourth layer 4 with a spraying method. Further, the fifth layer 5 may also be disposed between the third layer 3 and the fourth layer 4 (as shown in FIG. 2R).
Refer to FIG. 7 and FIG. 8 for the transmittance and the reflectivity of the anti-reflection coating structure of double ITO layers plus one protective layer and one anti-glare layer (the fifth layer) mentioned above. The portion of the transmittance curve with the transmittance over 90% and the portion of the reflectivity curve with the reflectivity below 10% are both smoothed.
Refer to FIG. 9A for a fourth embodiment of the present invention. In comparison with the third embodiment, the second anti-reflection coating structure B further comprises an eleventh layer 11 in the fourth embodiment. The eleventh layer 11 has a refractive index identical to that of the fourth layer 4 and is a protective layer disposed on the tenth layer 10. Another preferred embodiment structure is further form another anti-glare layer 5b with a rough surface on the surface of the fourth layer 4 of the first anti-reflection coating structure A such that an anti-glare effect can be obtained.
Thus, according to the fourth embodiment of the present invention, the second anti-reflection coating structure B of the touch panel of the present invention may also be a four-layer structure, and further includes the eleventh layer 11 The eleventh layer 11 has a refractive index identical to that of the fourth layer 4 and is a protective layer disposed on the tenth layer 10. The four-layer structure corresponding to the first anti-reflection coating structure (HLHL)A is in mirror symmetry. Thereby, the total transmittance of the touch panel will be more stable within the range of the wavelength of visible light. Similarly, according to the first anti-reflection coating structure A of FIGS. 2C, 2F, 2I, and 2M, the second anti-reflection coating structure B with mirror structure is formed on the rear side 12 of the substrate 6 as shown in FIGS. 2E, 2H, 2M and 2P. Besides, FIG. 2I shows the preferred embodiment based on the structure of FIG. 2H but lacks of the eleventh layer 11 with the plurality of particles 13. In FIG. 2M, the surface of the eleventh layer 11 further forms the fifth layer 5 (anti-glare layer) with a rough surface. In FIG. 2P, the fifth layer 5 (an anti-glare layer) is between the tenth layer 10 and the eleventh layer 11 to provide an anti-glare effect. In addition, FIG. 2Q shows the preferred embodiment based on the structure of FIG. 2P but lacks of the fifth layer 5 (an anti-glare layer). Furthermore, FIG. 2R shows the preferred embodiment based on the structure of FIG. 2P but lacks of the fifth layer 5 (an anti-glare layer) and the eleventh layer 11.
The achievements of the present invention will be further demonstrated below. Firstly, the transmittance is to be compared. As shown in FIG. 10, for the visible-light wavelength within from 380 to 780 nm, the transmittance of a plain glass substrate is within from 80 to 90%. As shown in FIG. 11, for a glass substrate coated with double ITO layers, the transmittance thereof is over 90% for the wavelength within from 442 to 625 nm; however, the transmittance thereof is below 80% for the wavelength smaller than 407 nm or greater than 747 nm. When the abovementioned glass substrate with double ITO layers is further coated with a protective layer of the present invention, the transmittance thereof is increased to over 92% for the wavelength within from 431 to 692 nm, as shown in FIG. 4. In other words, besides increasing abrasion resistance, the protective layer of the present invention also enlarges the portion of the transmittance curve with the transmittance over 92%; thus, the portion of the transmittance curve with the transmittance over 92% in the present invention is greater than that in the conventional glass substrate only with double ITO layers. As shown in FIG. 7, when the fifth layer 5 (an anti-glare layer) is coated on the touch panel, the portion of the transmittance curve with the transmittance over 90% is smoothed; in other words, the display performance of the touch panel is further stabilized thereby. As shown in FIG. 12, the transmittances of all the abovementioned cases are plotted on the same diagram for comparison.
Next, the reflectivity is to be compared. Refer to FIG. 5, and refer to from FIG. 13 to FIG. 15, wherein the Y-axes denote reflectivity. As shown in FIG. 13, for a plain glass substrate, the reflectivity is below 10% for the range of the wavelength of visible light. As shown in FIG. 14, for the glass substrate with double ITO layers, the reflectivity is lowered to below 5% for the wavelength within from 480 to 580 nm, and the reflectivity rises to below 10% for the wavelength below 440 nm or the wavelength over 660 nm. As shown in FIG. 5, for the glass substrate with double ITO layers plus one protective layer of the present invention, the portion of the reflectivity curve with the reflectivity below 10% is enlarged to range from 440 to 700 nm, which is greater than that for the glass substrate with only double ITO layers. As shown in FIG. 8, for the glass substrate with double ITO layers plus one protective layer and the fifth layer (anti-glare layer), the portion of the reflectivity curve with the reflectivity below 10% is smoothed. As shown in FIG. 15, the reflectivities of all the abovementioned cases are plotted on the same diagram for comparison.
Refer to Table 1 and FIG. 16. The total transmittances of the touch panels of the abovementioned cases are measured with the Haze-Gard Plus hazemeter according to ASTM-D1003 (Such a hazemeter is a standard instrument for measuring the total transmittance, the transmittance haze, and clarity of TFT-LCD). It can be seen that the touch panel of the present invention with the glass substrate having one protective layer or one protective layer plus one anti-glare layer is superior to the conventional touch panel with only plain glass substrate or with the glass substrate having double ITO layers.
TABLE 1
|
|
Glass substrate
|
Glass substrate
with double
|
with double
ITO layers plus
|
Glass substrate
ITO layers plus
one protective
|
Plain glass
with double
one protective
layer and one
|
substrate
ITO layers
layer
anti-glare layer
|
Substrate
(2.8 m/m)
(2.8 m/m)
(2.8 m/m)
(2.8 m/m)
|
|
T
92.2
93
93.7
93.2
|
|
Those preferred embodiments disclosed above are to clarify the present invention; however it is not intended to limit the scope of the present invention. Although any person skilled in the art is likely to be able to make equivalent modifications or variations according to the spirit of the present invention, any anti-reflection coating structure is to be also included within the scope of the claims of the present invention, which is otherwise designed and formed on the front side 7 and/or the rear side 12 of the substrate 6 according to the principle of the four-layer anti-reflection coating structure disclosed above. Further, the scope of the present depends on the claims stated below.
Patent Application
20070292659
