CN101055321A - High transmittance touch screen - Google Patents

Abstract

The invention discloses a high-transmittance touch screen, comprising a substrate and at least one multi-layer reflective structure. The multi-layer reflective structure is a four-layer structure coated on the front of the substrate. The refractive index of these film layers is designed to be high, low, high, and low, starting from the side adjacent to the substrate. The outermost layer is a protective layer with a protective function, the refractive index of which is between 1.3 and 1.5, the thickness is at least 0.1 micron, and the hardness passes the ASTM-D3363 international test standard of 9H. Through the design of this protective layer, the light transmittance of the touch screen of the invention can reach more than 92% of ASTM-D1003, and the wear resistance of its surface can also be enhanced.

Description

High transmittance touch screen

technical field

The invention relates to a touch screen with a multi-layer reflective structure, in particular to a capacitive touch screen with a protective layer as the surface layer of the multi-layer reflective structure to enhance the anti-wear effect. touch panel).

Background technique

Anti-reflective optical coatings were used in building materials such as glass and goggles in the past, but with the advancement of technology, this technology has gradually been transferred to semiconductors, optical disc read heads, liquid crystal displays, and touch panels. In the design principle of traditional anti-reflective optical coating layers, the layer coated on the contact substrate has a higher refractive index (i.e. H), and then faces this layer followed by another layer with a lower refractive index (i.e. L). Therefore, the structure of the traditional anti-reflection optical coating layer is H, L, H, L in order from the direction adjacent to the substrate.

And China Taiwan Patent Announcement No. 562736 (the same case as U.S. Patent No. 6,586,101), then proposes a technology that uses a transparent conductive layer as the surface layer of the anti-reflection optical coating layer, the anti-reflection optical coating layer of the case , also has a four-layer structure, and the design of the refractive index of each layer of film is L, H, L, H in order from the side adjacent to the substrate. Due to the above design, the transparent conductive layer is made on the outermost layer, so it is not necessary to use ultrasonic welding to destroy the surface layer to expose the transparent conductive layer of the lower layer, so as to overcome the resistance to mass production. Challenges in Reflective Optical Coatings.

To sum up, in the prior art mentioned above, all are emphasizing the performance of light transmittance and solving the difficult problems in the process, but none of them are particularly aimed at the abrasion resistance or anti-electromagnetic interference (EMI) of the outer layer of the anti-reflective optical coating layer. Or improve the stability of the overall light transmittance, and propose further solutions.

Contents of the invention

The main purpose of the present invention is to provide a high light transmittance touch screen, which is to coat a multi-layer reflective structure on the front surface of the substrate, wherein the outermost layer of the multi-layer structure is a protective layer, so the high transmittance of the present invention In addition to high light transmittance, the optical touch screen can further have anti-wear properties through the protective layer.

Another object of the present invention is to provide a high light transmittance touch screen, which is to coat another multi-layer reflective structure on the back surface of the substrate to further reduce reflection and increase light transmittance, and has anti-electromagnetic interference (EMI) ) function.

Yet another object of the present invention is to provide a touch screen with high light transmittance, which can add a fifth layer (anti-glare layer) (anti- Glare layer), so that the overall light transmittance can be more stable in the visible light wavelength range.

Based on the above-mentioned main purpose, the present invention provides a high light transmittance touch screen, comprising a substrate and a first anti-reflection coating layer structure coated on the front of the substrate, the preferred mode of the layer structure is to design the refractive index It is a four-layer structure of high, low, high, and low (counting from the side adjacent to the substrate), and the four-layer structure is called the first to fourth layers. The first layer is an oxide layer with a refractive index higher than 1.5; the second layer is an oxide layer with a refractive index between 1.3 and 1.5; the third layer is a transparent conductive layer with a refractive index between 1.8 and A refractive index of 2.5, and has an impedance value between 200-10000 ohms/unit area; the fourth layer is a protective layer, has a refractive index between 1.3-1.5, has a thickness of at least 0.1 microns (μm), and a hardness Passed the ASTM-D3363 international inspection standard of 9H.

In addition, based on the above another purpose, the present invention provides a high light transmittance touch screen, which is to coat a second anti-reflection coating layer structure on the back surface of the substrate, wherein the preferred mode of the structure is to design its refractive index It is a three-layer structure of high, low, and high (counting from the side adjacent to the substrate), and the three-layer structure is called the eighth to tenth layers. The eighth layer has the same refractive index as the first layer; the ninth layer has the same refractive index as the second layer; the tenth layer has the same refractive index as the first layer, and has an impedance value of 10-10 ⁵ ohms/unit area.

In addition, the touch screen with high light transmittance provided by the present invention can also make the surface of the substrate rough by dipping or etching the front and back sides of the substrate under the reflective structure with only four layers on the front side of the substrate. shape so as to have an anti-glare effect; in addition, particles can also be added to the outermost layer (ie, the protective layer) of the above-mentioned four-layer reflective structure to achieve an anti-glare effect. Of course, a fifth layer (anti-glare layer) can also be formed on the surface of the fourth layer, or between the third layer and the fourth layer.

In summary, in addition to high light transmittance, the high light transmittance touch screen according to the present invention also has anti-wear characteristics and anti-electromagnetic interference (EMI) functions, and the overall light transmittance is within the wavelength range of visible light performance is more stable.

Description of drawings

FIG. 1 is a cross-sectional view of a first preferred embodiment of a high light transmittance touch screen of the present invention.

2-1 to 2-5 are cross-sectional views of the second preferred embodiment of the high transmittance touch screen of the present invention.

FIG. 3 is a cross-sectional view of a state of the third preferred embodiment of the high light transmittance touch screen of the present invention.

FIG. 6 is a cross-sectional view of another state of the third preferred embodiment of the high transmittance touch screen of the present invention.

FIG. 9 is a cross-sectional view of a fourth preferred embodiment of the high light transmittance touch screen of the present invention.

Fig. 4, Fig. 7, Fig. 10 to Fig. 12 are diagrams showing the relationship between the light transmittance and the wavelength range of visible light in the present invention and the prior art.

Fig. 5, Fig. 8, Fig. 13 - Fig. 15 are diagrams showing the relationship between the reflectance and the wavelength range of visible light in the present invention and the prior art.

Fig. 16 is a graph showing the relationship between the overall transmittance measured by the Haze-Gard Plus haze meter according to the ASTM-D1003 international standard of the present invention and the prior art.

Detailed ways

Relevant preferred embodiment of the present invention and technical content, now in conjunction with accompanying drawing are described as follows:

First, please refer to FIG. 1 , in the first embodiment, the high transmittance touch screen of the present invention has a substrate 6 and a first anti-reflection coating layer structure A. As shown in FIG. Wherein, the substrate 6 has a front surface 7 and a reverse surface 12 relative to the front surface 7. It is defined here that the front surface 7 refers to the side adjacent to the user, and the reverse surface 12 refers to the side adjacent to the backlight source. The substrate 6 can be It is made of glass, plastic or other transparent materials; the first anti-reflection coating layer structure A is a four-layer structure, including a first layer 1, a second layer 2, a third layer 3 and a first layer Four layers 4, and the first layer 1, the second layer 2, the third layer 3 and the fourth layer 4 are sequentially arranged on the front surface 7 of the substrate 6 from the side adjacent to the substrate 6, and the configuration of these layers can be Formed by vacuum coating techniques such as sputtering, evaporation, chemical vapor deposition or other wet coating technologies.

The first layer 1 is an oxide layer with a refractive index higher than 1.5; and in this embodiment, the material of the first layer 1 is, for example, niobium pentoxide (Nb ₂ O ₅ ). Of course, the material of the first layer 1 can also be selected from the group consisting of indium tin oxide (ITO), antimony tin oxide (ATO), niobium oxide, titanium oxide, tantalum oxide ) and their mixed oxides (mixtures of these oxides).

The second layer 2 is an oxide layer with a refractive index ranging from 1.3 to 1.5; in this embodiment, the material of the second layer 2 is, for example, silicon dioxide (SiO ₂ ). In addition, the material of the second layer 2 can also be porous, fluorinated or organically modified low refractive index material.

The third layer 3 is a transparent conductive layer with a refractive index between 1.8-2.5 and an impedance value between 200-10000 Ohm/unit area (Ohm/square); in this embodiment , the third layer 3 is connected to the electrode pattern on the edge of the touch panel; in addition, the material of the third layer 3 is, for example, niobium pentoxide (Nb ₂ O ₅ ) added to indium tin oxide (ITO) . Of course, the material of the third layer 3 can also be antimony tin oxide (ATO), indium tin oxide (ITO), tin dioxide (SnO ₂ ), zinc dioxide (ZnO ₂ ), indium trioxide (In ₂ O ₃ ) and combinations thereof, where indium tin oxide (ITO) refers to pure ITO (pure ITO). However, the above-mentioned additive (Nb ₂ O ₅ ) can be added or not according to requirements, and the added content accounts for about 0.1-20% of the whole.

The fourth layer 4 is a protective layer with a refractive index between 1.3 and 1.5, the thickness of the layer is at least 0.1 micrometer (μm), and the hardness of the layer passes the ASTM-D3363 international inspection standard of 9H, and Can pass at least 1,000 scratch resistance tests of the U.S. Army military standard (military standard MIL-C-675C); in this embodiment, the material of the fourth layer 4 can be silicon dioxide (SiO ₂ ) or organic Modified silica (organically modified silica).

As can be seen from the above, the present invention coats a four-layer anti-reflection coating layer on the front surface 7 of the substrate 6 of the touch screen. Low, high, low (expressed as H, L, H, L), so that the light transmittance of the touch screen of the present invention can reach more than 92% of ASTM-D1003. In addition, because the outermost layer of these film layers is defined as a protective layer, and through the design of the protective layer, the abrasion resistance of the surface can be enhanced.

Next, please refer to Figure 2-1 to Figure 2-5, which are the second preferred embodiment of the present invention. There are five states, as shown in Figure 2-1, under the above-mentioned four-layer anti-reflection structure, you can also The two sides of the substrate 6 are pickled or etched to roughen the surfaces of the front and back sides 7, 12 of the substrate 6, thereby having an anti-glare effect. Of course, the method is not limited to the above-mentioned method of double-sided pickling or acid etching. As shown in FIG. 2-2 , a rough surface can be formed only on the front side 7 of the substrate 6 close to the user. In addition, as shown in Figures 2-3, it is also possible to add several particles (particles) 13 to the outermost layer (that is, the fourth layer 4) of the above-mentioned four-layer antireflection structure, so that the refractive index of the particles 13 becomes 1.5 to 1.5. 2.5, so as to achieve the anti-glare effect, and the diameter of the particles 13 is between 0.01-4 microns (μm). In addition, it is also possible to spray a fifth layer (anti-glare layer) 5 on the fourth layer 4 of the anti-reflection structure under the above-mentioned four-layer anti-reflection structure, as shown in Figure 2-4. The glare layer) 5 is formed by spraying, and the average roughness (roughness) is between 0.01-0.4 microns (μm), which can roughen the surface and thus have an anti-glare effect. Certainly, the fifth layer (anti-glare layer) 5 mentioned above is not limited to be formed after the anti-reflection structures of the four layers are all fabricated, and may also be formed after the third layer is fabricated as shown in Fig. 2-5. After 3, the fifth layer (anti-glare layer) 5 is sprayed, and finally the fourth layer 4 is formed.

Next, please refer to Fig. 3, which is one of the states of the third preferred embodiment of the present invention. layer 8, a ninth layer 9, and a tenth layer 10, and the eighth layer 8, the ninth layer 9, and the tenth layer 10 are sequentially arranged on the reverse surface 12 of the substrate 6 from the side adjacent to the substrate 6, these Layers can also be formed using vacuum coating techniques such as sputtering, evaporation, chemical vapor deposition or other wet coating techniques.

The refractive index of the eighth layer 8 is equal to that of the first layer 1; the refractive index of the ninth layer is equal to that of the second layer 2; the refractive index of the tenth layer 10 is equal to that of the third layer 3, and has 10-10 ⁵ ohms/unit The impedance value of the area and is connected to the conductor (conductor) at the edge of the panel. In this embodiment, the tenth layer 10 may be an indium tin oxide (ITO) layer, and has an impedance value of 100˜700 ohm/unit area (ohm/square).

As can be seen from the above, the present invention coats a three-layer structure anti-reflection coating layer on the reverse side 12 of the substrate 6 of the touch screen, and the refractive index of these film layers is calculated from the side adjacent to the substrate 6, and is successively designed to be high. , low, high (expressed as H, L, H), so that the touch screen of the present invention can further reduce reflection and increase light transmittance, and the design of the tenth layer 10 can also have the function of preventing electromagnetic interference (EMI) .

Under the structure of the above-mentioned double-layer ITO plus a protective layer, the performance of its light transmittance and reflectance can refer to Figure 4 and Figure 5. In the wavelength range of 431-692nm, the average light transmittance can be increased to 92%. above; the reflectance is lower than 10% in the wavelength range of 440-700nm.

Then, please refer to Fig. 6, which is another implementation state of the third preferred embodiment of the present invention, its difference with respect to Fig. 3 is that on the fourth layer 4 of the anti-reflection structure, a fifth layer (anti-glare) can be sprayed equally layer) 5. Of course, the fifth layer (anti-glare layer) 5 may also be disposed between the third layer 3 and the fourth layer 4 as described above (not shown).

And under the structure of the above-mentioned double-layer ITO plus a protective layer and a fifth layer (anti-glare layer) 5, the performance of its light transmittance and reflectance can refer to Figure 7 and Figure 8, especially the light transmittance can be greater than It is equal to 90% and the reflectivity is adjusted to a smoother curve in the range of less than or equal to 10%.

Next, please refer to FIG. 9, which is the fourth preferred embodiment of the present invention. The difference between this embodiment and the third preferred embodiment is that the second anti-reflection coating layer structure B may also include an eleventh layer 11, Its refractive index is equal to that of the fourth layer 4 , and this eleventh layer 11 is a protective layer arranged on the tenth layer 10 .

As can be seen from the above, the second anti-reflection coating layer structure B in the touch screen of the present invention can also be increased to a four-layer structure, and its refractive index is just a mirror image with respect to the first anti-reflection coating layer structure (HLHL) A (mirror) configuration design, so that the performance of the overall light transmittance in the wavelength range of visible light can be more stable.

The effect that the present invention can achieve can also be further proved from the following and corresponding drawings. Firstly, the comparison of light transmittance is explained. For a simple glass substrate, the overall light transmittance is between 80% and 90% in the visible light range with a wavelength of 380-780nm (as shown in Figure 10); After the glass substrate is coated with double-layer ITO, the light transmittance can be increased to more than 90% in the wavelength range of 442-625nm, but the light transmittance in the wavelength range of less than 407nm and greater than 747nm drops to below 80% ( As shown in Figure 11); after further coating the protective layer of the present invention based on the above, the light transmittance can be increased to more than 92% on average in the segment of 431-692nm wavelength (as shown in Figure 4); in other words , after the present invention is coated with the protective layer, in addition to increasing the anti-abrasion effect, the range of light transmittance above 92% is wider than that of the glass substrate coated with double-layer ITO; then, please Referring to Fig. 7, when the present invention adds the fifth layer (anti-glare layer) 5, especially the section with light transmittance above 90% can be adjusted to a relatively smooth curve; in other words, the touch screen can be further stabilized performance on display. For the overall comparison of the light transmittance of the above graph in the visible light range, refer to FIG. 12 .

Next, please refer to Fig. 5, Fig. 13-Fig. 15. The Y-axis of these figures is represented by reflectance. If only a glass substrate is used, and the wavelength is in the visible light range, the overall reflectance is below 10% (such as As shown in Figure 13); after coating double-layer ITO on the glass substrate, the reflectance in the wavelength range of 480-580nm drops below 5%, but the reflectance in the wavelength range of less than 440nm and greater than 660nm increases More than 10% (as shown in Figure 14); after further coating the protective layer of the present invention, the reflectivity of the section below 10% can be increased to the wavelength The scope of 440～700nm (as shown in Figure 5); When the present invention adds the 5th layer (anti-glare layer) 5 again, especially can adjust the section of reflectance below 10% to be comparatively smooth curve, and then Improve the performance of the touch screen on the display (as shown in Figure 8). For the overall comparison of the reflectance of the above graph in the visible light range, refer to FIG. 15 .

In addition, please refer to the following Table 1 and Figure 16, which shows the Haze-Gard Plus haze meter used according to the ASTM-D 1003 international standard (the haze meter is used to measure the penetration of TFT-LCD, such as total transmittance, transmittance The overall transmittance measured by the standard instrument of haze and perspective clarity), it can be seen from the results that the present invention has an additional layer of protective layer or the fifth layer (anti-glare layer) Under the structure of pure glass substrate or double-layer ITO, its overall penetration rate is indeed better than that of the existing technology.

Table I Glass substrate (plain glass) 2.8m/m Double layer ITO2.8m/m Double-layer ITO+ single-layer protective layer 2.8m/m Double-layer ITO + single-layer protective layer + fifth layer (anti-glare layer) 2.8m/m T 92.2 93 93.7 93.2

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. In the above-described embodiments, various modifications and changes are possible to the present invention. Within the spirit and principles of the present invention, any modifications, equivalent replacements, improvements, etc., such as on the front side 7 or the back side 12 of the substrate 6, are repeated to form more The anti-reflective layer of the layer should be included in the protection scope of the present invention.

Claims (16)

1. high light transmittance ratio touch screen is characterized in that comprising:

One substrate has a positive and reverse side with respect to described front; And

One first reflection coating layer structure, comprise a ground floor, a second layer, one the 3rd layer and one the 4th layer, and outside a side direction that is adjacent to described substrate with described ground floor, the described second layer, described the 3rd layer and described the 4th layer arranged in order on the described front of described substrate, wherein:

Described ground floor is the monoxide layer, has to be higher than 1.5 refractive index;

The described second layer is the monoxide layer, has the refractive index between 1.3～1.5;

Described the 3rd layer is a transparent conductive layer, has the refractive index between 1.8～2.5, and has the resistance value between 200～10000 ohm/unit area;

Described the 4th layer is a protective seam, has the refractive index between 1.3～1.5, and described the 4th layer thickness is at least 0.1 micron (μ m), and described the 4th layer hardness is by the international test stone of the ASTM-D3363 of 9H.

2. high light transmittance ratio touch screen according to claim 1 is characterized in that: the material of described ground floor is to be selected from niobium pentaoxide (Nb ₂O ₅), tin indium oxide (ITO), antimony tin (ATO), niobium oxide (niobium oxide), titanium oxide (titanium oxide), tantalum pentoxide (tantalum oxide) and the oxide (mixtures of these oxide) that mixes thereof.

3. high light transmittance ratio touch screen according to claim 1 is characterized in that: the material of the described second layer is silicon dioxide (SiO ₂).

4. high light transmittance ratio touch screen according to claim 1 is characterized in that: the material of the described second layer is the low-refraction material of poriness (porous), interpolation chlorine element (fluorinated) or organic transformation (organically modified).

5. high light transmittance ratio touch screen according to claim 1 is characterized in that: described the 3rd layer material is that tin indium oxide (ITO) adds niobium pentaoxide (Nb ₂O ₅) additive.

6. high light transmittance ratio touch screen according to claim 1 is characterized in that: described the 3rd layer optional autoxidation antimony of material tin (ATO), tin indium oxide (ITO), tin ash (SnO ₂), zinc oxide (ZnO ₂), indium sesquioxide (In ₂O ₃) and combination.

7. high light transmittance ratio touch screen according to claim 1 is characterized in that: described the 4th layer material is silicon dioxide (SiO ₂) or organic transformation tripoli (organicallymodified silica).

8. high light transmittance ratio touch screen according to claim 1, it is characterized in that: the described first reflection coating layer structure also comprises a layer 5, described layer 5 is to be configured in the anti-photosphere (anti-glare layer) of dazzling of one on described the 4th layer, described layer 5 (the anti-photosphere of dazzling) has a rough surface (rough surface), and mean roughness (roughness) is between 0.01～0.4 micron (μ m).

9. high light transmittance ratio touch screen according to claim 1 is characterized in that: the described front of described substrate and described reverse side or only described front are a roughened surface.

10. high light transmittance ratio touch screen according to claim 1, it is characterized in that: also further be added with a plurality of particulates (particle) in described the 4th layer, the diameter of these particulates makes described particulate have 1.5～2.5 refractive index between 0.01～4 micron (μ m).

11. high light transmittance ratio touch screen according to claim 1, it is characterized in that: also comprise a layer 5, described layer 5 is one to be configured in the anti-photosphere of dazzling between described the 3rd layer and described the 4th layer, described layer 5 (the anti-photosphere of dazzling) has a rough surface (roughsurface), and mean roughness (roughness) is between 0.01～0.4 micron (μ m).

12. high light transmittance ratio touch screen according to claim 1, it is characterized in that: also comprise one second reflection coating layer structure, comprise one the 8th layer, one the 9th layer and 1 the tenth layer, and outside a side direction that is adjacent to described substrate with described the 8th layer, the arranged in order of described the 9th layer and the described ten layer on the described reverse side of described substrate, wherein:

Described the 8th layer refractive index is equal to described ground floor;

Described the 9th layer refractive index is equal to the described second layer;

The described ten layer refractive index is equal to described the 3rd layer, and has 10～10 ⁵The resistance value of ohm/unit area (ohm/square).

13. high light transmittance ratio touch screen according to claim 12 is characterized in that: the described ten layer is a tin indium oxide (ITO) layer, and has the resistance value of 100～700 ohm/unit area (ohm/square).

14. high light transmittance ratio touch screen according to claim 12; it is characterized in that: the described second reflection coating layer structure also comprises an eleventh floor; the refractive index of described eleventh floor is equal to described the 4th layer, and described eleventh floor is one to be configured in the protective seam on the described ten layer.

15. high light transmittance ratio touch screen according to claim 12, it is characterized in that: also comprise a layer 5, described layer 5 is to be configured in the anti-photosphere of dazzling of one on described the 4th layer, described layer 5 (the anti-photosphere of dazzling) has a rough surface (rough surface), and mean roughness (roughness) is between 0.01～0.4 micron (μ m).

16. high light transmittance ratio touch screen according to claim 12, it is characterized in that: also comprise a layer 5, described layer 5 is to be configured in the anti-photosphere of dazzling of one between described the 3rd layer and described the 4th layer, described layer 5 (the anti-photosphere of dazzling) has a rough surface (rough surface), and mean roughness (roughness) is between 0.01～0.4 micron (μ m).

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