TWI718739B - Optical assembly - Google Patents

Abstract

An optical assembly adapted to dispose on a display surface of a display device is provided. The optical assembly includes an optical film stack and at least one electrode element. The optical film stack includes a plurality of optical films of different refractive index and at least one optical control film. The at least one electrode element is electrically connected to the at least one optical control film, wherein the reflectivity of the optical film stack to ambient light is less than or equal to 1%, and the at least one optical control film is adapted to increase the reflectivity to the ambient light by greater than or equal to 1% by applied a voltage.

Description

Optical accessories

The present invention relates to an optical device, and particularly relates to an optical accessory.

Generally speaking, the surface of electronic screens (such as computer monitors, robots, smart phones or tablet computers, etc.) is often coated with an anti-reflection layer to reduce reflections caused by ambient light and reduce visibility. In a specific practice, a single layer or multiple layers of material can be coated between the transparent substrate and the air to reduce the reflection at the interface between the glass and the air.

However, in general electronic screens, the coated anti-reflection layer is a passive optical function layer. In other words, other kinds of optical effects cannot be produced by further control. If it can be changed to an active optical function layer, the electronic screen can be used for more purposes when viewed, such as security functions such as color change or anti-peeping. Therefore, how to design a passive optical function layer as an active optical function layer to produce other kinds of optical effects is what the art needs to focus on.

The present invention provides an optical accessory, which can switch the anti-reflection function or the non-anti-reflection function in different situations to achieve a good optical display effect or anti-peeping effect.

An embodiment of the present invention provides an optical accessory for installation on a display surface of a display device. The optical accessory includes an optical film stack and at least one electrode element. The optical film stack includes a plurality of optical films with different refractive indexes and at least one optical control film. At least one electrode element is correspondingly electrically connected to at least one optical control film, wherein the reflectance of the optical film stack to an ambient light is less than or equal to 1%, and at least one optical control film is adapted to increase the resistance to ambient light by being applied with a voltage. The reflectivity is greater than or equal to 1%.

In an embodiment of the present invention, the above-mentioned at least one optical control film improves the reflectivity of ambient light by changing the refractive index or the extinction coefficient.

In an embodiment of the present invention, the number of the aforementioned at least one optical control film is the same as the number of the at least one electrode element.

In an embodiment of the present invention, the number of the above-mentioned at least one optical control film and the number of the at least one electrode element are both one.

In an embodiment of the present invention, at least one of the aforementioned at least one optical control film is located between the optical film and the display surface.

In an embodiment of the present invention, the above-mentioned optical film includes at least one first optical film and at least one second optical film stacked in a staggered manner, and the refractive index of the at least one first optical film is greater than that of the at least one second optical film.

In an embodiment of the present invention, the material of the at least one optical control film mentioned above is the same as the material of the at least one first optical film.

In an embodiment of the present invention, the above-mentioned electrode elements are distributed at the edge of the display device.

In an embodiment of the present invention, the above-mentioned electrode element distribution positions correspond to the positions of multiple display pixels in the display device.

In an embodiment of the present invention, the above-mentioned optical accessory is detachably provided on the display device.

Based on the above, in the optical accessory of the present invention, the optical film stack of the optical accessory is composed of a plurality of optical films with different refractive indexes and at least one optical control film. Therefore, the anti-reflection function can be generated under normal circumstances, and the display device can achieve a good optical display effect. The optical control film can change the refractive index and extinction coefficient by controlling the control of the electrode element. In this way, the anti-reflection function or the non-anti-reflection function can be switched in different situations, thereby achieving a good optical display effect or anti-peeping effect.

In order to make the above-mentioned features and advantages of the present invention more comprehensible, the following specific embodiments are described in detail in conjunction with the accompanying drawings.

FIG. 1 is a schematic diagram of an optical accessory disposed on a display surface of a display device according to an embodiment of the present invention. Please refer to Figure 1. This embodiment provides an optical accessory 100 for being arranged on a display surface S of a display device 10. The optical accessory 100 is, for example, directly fabricated on the display surface S of the display device 10, or detachably installed on the display device 10, but the present invention is not limited to this. For example, the optical accessory 100 may be a screen pendant mounted on the display device 10 to cover the display surface S.

In detail, in this embodiment, the optical accessory 100 includes an optical film stack 110 and at least one electrode element 120. The optical film stack 110 includes a plurality of optical films 112 with different refractive indexes and at least one optical control film 114. In this embodiment, the optical film 112 includes at least one first optical film 112_1 and at least one second optical film 112_2 stacked alternately, wherein the refractive index of the at least one first optical film 112_1 is greater than that of the at least one second optical film 112_2. For example, in this embodiment, the optical film stack 110 is composed of a first optical film 112_1, two second optical films 112_2, and an optical control film 114, which are sequentially composed of the optical control film 114, the optical control film 114, and the optical control film 114 from the bottom to the top. The second optical film 112_2, the first optical film 112_1, and the second optical film 112_2 are stacked. In other words, in this embodiment, the refractive index is high, low, high, and low in order from bottom to top, but the present invention is not limited to this. It is worth mentioning that in this embodiment, the uppermost layer of the optical film stack 110 is a film layer with a relatively small refractive index, that is, the second optical film 112_2 is arranged on the uppermost layer of the optical film stack 110. In an embodiment with a five-layer stack structure in the optical film stack, the optical control film 114, the first optical film 112_1, the second optical film 112_2, the first optical film 112_1, and the second optical film can be arranged in order from bottom to top. 112_2 is stacked, wherein the optical control film 114 can be made of the same material as the second optical film 112_2 or other materials with a lower refractive index than the first optical film 112_1. In other words, the refractive index is low, high, low, high, and low in order from bottom to top. In this embodiment, at least one of the optical control films 114 is located between the optical film 112 and the display surface S, but the invention is not limited to this.

The first optical film 112_1 and the optical control film 114 can be selected from tungsten trioxide (WO3) or niobium pentoxide (Nb ₂ O ₅ ), and the second optical film 112_2 can be selected from silicon dioxide (Silicon dioxide , SiO ₂ ). In other words, in this embodiment, the material of the optical control film 114 is the same as the material of the first optical film 112_1. In other embodiments, the material of the optical control film 114 and the material of the first optical film 112_1 can be made of different materials, and the present invention is not limited thereto. Therefore, under the staggered stacking of the niobium pentoxide optical film and the silicon dioxide optical film, the reflectivity of the optical film stack 110 to the ambient light L can be less than or equal to 1%, thereby achieving the anti-reflection function.

The electrode element 120 is electrically connected to the optical control film 114 correspondingly. Specifically, the electrode elements 120 are, for example, a pair of electrode structures distributed at the edge of the display device 10, or the distribution positions of the electrode elements 120 correspond to the positions of multiple display pixels in the display device 10. The present invention is not limited to this. . In addition, in this embodiment, the number of the electrode element 120 and the optical control film 114 is the same, for example, both are one. However, in other embodiments, the same number of multiple electrode elements 120 and multiple optical control films 114 can also be used, and the present invention is not limited to this. In this embodiment, the electrode element 120 can be triggered by an external physical button, or it can be activated by computer software control, and the present invention is not limited to this.

Fig. 2 is a graph showing the change of light transmittance of a conventional material to different wavelengths under different voltages. Fig. 3 is a graph showing the change of the refractive index of the material of Fig. 2 to light of different wavelengths under different heat treatments. Fig. 4 is a graph showing the change of the light extinction coefficient of the material of Fig. 2 at different wavelengths under different heat treatments. Please refer to Figure 1 to Figure 4. It should be noted that the graphs of the material properties in Figures 2 to 4 are quoted from the article in the journal Proceedings of SPIE-The International Society for Optical Engineering 8902:24 (2013): Characterization and application of WO3 films for electrochromic devices . The optical control film 114 and the first optical film 112_1 of this embodiment can use the materials taught in FIGS. 2 to 4, so the following description will take the optical control film 114 and the first optical film 112_1 using tungsten trioxide as an example . In one embodiment, the material of the optical control film 114 and the first optical film 112_1 is tungsten trioxide. The optical control film 114 using tungsten trioxide as a material is suitable for increasing the reflectivity of the ambient light L by greater than or equal to 1% by being applied with a voltage. Specifically, when the electrode element 120 applies different voltages to the optical control film 114, the transmittance of the optical control film 114 to light of different wavelengths changes with different voltages, as shown in FIG. 2.

In detail, as shown in Figure 2, the X-axis coordinate represents the wavelength of the ambient light, and the unit is nanometers. The Y-axis coordinate represents the transmittance of ambient light, which is displayed as a percentage. The line segment 201 represents the transmittance of the optical control film 114 to light of different wavelengths when the electrode element 120 does not apply a voltage to the optical control film 114. The line 202 represents the transmittance of the optical control film 114 to light of different wavelengths when the electrode element 120 applies a voltage of 1 volt to the optical control film 114. The line segment 203 represents the transmittance of the optical control film 114 to light of different wavelengths when the electrode element 120 applies a voltage of 2 volts to the optical control film 114. The line segment 204 represents the transmittance of the optical control film 114 to light of different wavelengths when the electrode element 120 applies a 3 volt voltage to the optical control film 114. The line segment 205 represents the transmittance of the optical control film 114 to light of different wavelengths when the electrode element 120 applies a 4 volt voltage to the optical control film 114. The line segment 206 represents the transmittance of the optical control film 114 to light of different wavelengths when the electrode element 120 applies a voltage of 5 volts to the optical control film 114.

In other words, the optical control film 114 has different transmittances for different wavelengths of light with different voltages, because the refractive index or extinction coefficient of the optical control film 114 is changed. In some embodiments, different processing treatments may be performed when the optical control film 114 is made according to different requirements. For example, as shown in FIG. 3 and FIG. 4, in FIG. 3, the X-axis coordinate represents the wavelength of the ambient light, and the unit is nanometer. The Y-axis coordinate represents the refractive index to ambient light. In Figure 4, the X-axis coordinates represent the wavelength of the ambient light in nanometers. The Y-axis coordinate represents the extinction coefficient of ambient light. The line segment 301 represents the refractive index of the optical control film 114 to light of different wavelengths before the thermal processing. The line segment 302 represents the refractive index of the optical control film 114 to light of different wavelengths after 400 degrees Celsius thermal processing. The line segment 401 represents the extinction coefficient of the optical control film 114 to light of different wavelengths before the thermal processing. The line segment 402 represents the extinction coefficient of the optical control film 114 to light of different wavelengths after 400 degrees Celsius thermal processing.

Therefore, the optical control film 114 shown in FIG. 2 can change the characteristics of different transmittances when different voltage values are applied, and the optical control film 114 shown in FIG. 3 can change the characteristics of different refractive index and extinction coefficient under different thermal processing treatments. It can be seen that in the optical accessory 100, the electrode element 120 can be used to apply a voltage to the optical control film 114 to change the refractive index of the optical control film 114 to produce transmittance to light of different wavelengths, thereby eliminating the resistance to ambient light L. The reflection function prevents the user from obtaining clear image information from the display surface S of the display device 10. In other words, the optical control film 114 to which a voltage is applied can also provide an anti-peeping effect. In this way, the refractive index and extinction coefficient of the optical control film 114 can be controlled by manipulating the electrode element 120 to switch the anti-reflection function or the non-anti-reflection function in different situations, thereby achieving a good optical display effect or anti-peeping effect . In addition, compared with general electrochromic materials, this embodiment can further save the components required for the configuration of electrochromic materials such as electrolyte.

It is worth mentioning that if the optical control film 114 is made of tungsten trioxide, it can produce a deep blue color by being applied with a voltage. In some embodiments, the optical control film 114 may be made of molybdenum oxide, niobium oxide, or titanium oxide. Therefore, different opaque colors can be produced by being applied with voltage. Therefore, the anti-peeping effect of the display surface S can be further improved.

In summary, in the optical accessory of the present invention, the optical film stack of the optical accessory is composed of a plurality of optical films with different refractive indexes and at least one optical control film. Therefore, the anti-reflection function can be generated under normal circumstances, and the display device can achieve a good optical display effect. The optical control film can change the refractive index and extinction coefficient by controlling the control of the electrode element. In this way, the anti-reflection function or the non-anti-reflection function can be switched in different situations, thereby achieving a good optical display effect or anti-peeping effect.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention. Anyone with ordinary knowledge in the relevant technical field can make some changes and modifications without departing from the spirit and scope of the present invention. The scope of protection of the present invention shall be determined by the scope of the attached patent application.

10: Display device 100: Optical accessories 110: Optical film stack 112: Optical film 112_1: the first optical film 112_2: The second optical film 114: Optical control film 120: Electrode element 201~206, 301, 302, 401, 402: line segment L: ambient light S: display surface

FIG. 1 is a schematic diagram of an optical accessory disposed on a display surface of a display device according to an embodiment of the present invention. Fig. 2 is a graph showing the change of light transmittance of a conventional material to different wavelengths under different voltages. Fig. 3 is a graph showing the change of the refractive index of the material of Fig. 2 to light of different wavelengths under different heat treatments. Fig. 4 is a graph showing the change of the extinction coefficient of the material of Fig. 2 for different wavelengths under different heat treatments.

10: Display device

100: Optical accessories

110: Optical film stack

112: Optical film

112_1: the first optical film

112_2: The second optical film

114: Optical control film

120: Electrode element

L: ambient light

S: display surface

Claims (9)

An optical accessory, which is used to be arranged on a display surface of a display device, includes: an optical film stack, including a plurality of optical films with different refractive indexes and at least one optical control film; and at least one electrode element correspondingly electrically connected to The at least one optical control film, wherein the reflectance of the optical film stack to an ambient light is less than or equal to 1%, and the at least one optical control film is adapted to be applied with a voltage to increase the reflectance of the ambient light to be greater than or equal to 1%, the at least one optical control film improves the reflectivity of the ambient light by changing the refractive index or the extinction coefficient. According to the optical accessory described in claim 1, wherein the number of the at least one optical control film is the same as the number of the at least one electrode element. According to the optical accessory described in claim 1, wherein the number of the at least one optical control film and the number of the at least one electrode element are both one. According to the optical accessory described in claim 1, wherein at least one of the at least one optical control film is located between the optical films and the display surface. The optical accessory according to claim 1, wherein the optical films include at least one first optical film and at least one second optical film stacked in a staggered manner, and the refractive index of the at least one first optical film is greater than that of the at least one optical film. The second optical film. According to the optical accessory described in claim 1, wherein the material of the at least one optical control film is the same as the material of the at least one first optical film. According to the optical accessory described in item 1 of the scope of patent application, the electrode elements are distributed at the edge of the display device. As described in the first item of the scope of patent application, the distribution position of the electrode element corresponds to the position of a plurality of display pixels in the display device. The optical accessory as described in item 1 of the scope of patent application, wherein the optical accessory is detachably arranged on the display device.

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