Brightness enhancement film assembly, optical film group, display device and electronic equipment

Abstract

The invention discloses a brightness enhancement film assembly, an optical film group, a display device and electronic equipment, and belongs to the technical field of display device design. The brightness enhancement film assembly comprises at least two brightness enhancement films, the at least two brightness enhancement films comprise a first brightness enhancement film and a second brightness enhancement film which are stacked, the first working wave band of the first brightness enhancement film is different from the second working wave band of the second brightness enhancement film, the maximum wavelength of the first working wave band is smaller than 555 nm, and the maximum wavelength of the second working wave band is smaller than 555 nm. The minimum wavelength of the second working wave band is larger than 555 nm. According to the scheme, the problem that a display device related to the related technology is poor in display effect can be solved.

Description

Technical Field

[0001] The present application belongs to the technical field of display device design, and specifically relates to a brightness enhancement film assembly, an optical film group, a display device and an electronic device. Background Art

[0002] Display devices are typically equipped with a brightness enhancement film that selectively reflects light, thereby improving the display quality. Specifically, to achieve a high brightness enhancement ratio, the related art typically ensures that the operating wavelength of the brightness enhancement film overlaps as closely as possible with the luminous spectrum of the display device's light-emitting layer, while also increasing the reflectivity of the brightness enhancement film. This allows the film to selectively reflect more light, thereby improving the display quality.

[0003] However, since the brightness enhancement film can selectively reflect more light, more light will be reflected to the non-luminous area of ​​the display device at an oblique angle and thus be absorbed, and the brightness attenuation of the display device at an oblique angle will be higher. At the same time, since the reflectivity of the brightness enhancement film is relatively high, the reflectivity of the brightness enhancement film to external light is also relatively high, which can easily affect the display effect of the display device.

[0004] In summary, the display devices involved in the related art have the problem of poor display effects. Summary of the Invention

[0005] The present application discloses a brightness enhancement film assembly, an optical film assembly, a display device, and an electronic device to solve the problem of poor display effect of the display device involved in the related art.

[0006] In order to solve the above technical problems, this application adopts the following technical solutions: A brightness enhancing film assembly includes at least two brightness enhancing films, wherein the at least two brightness enhancing films include a first brightness enhancing film and a second brightness enhancing film stacked together, wherein a first operating band of the first brightness enhancing film is different from a second operating band of the second brightness enhancing film, and a maximum wavelength of the first operating band is less than 555 nm, and a minimum wavelength of the second operating band is greater than 555 nm.

[0007] An optical film group includes a circularly polarizing film and the brightness enhancing film assembly described above. In the thickness direction of the optical film group, the circularly polarizing film and the brightness enhancing film assembly are stacked in sequence, and the handedness of the circularly polarized light reflected by the first brightness enhancing film and the handedness of the circularly polarized light reflected by the second brightness enhancing film are opposite to the handedness of the circularly polarized light transmitted by the circularly polarizing film.

[0008] A display device comprises a light-emitting layer and the optical film group described above. In the thickness direction of the display device, the optical film group and the light-emitting layer are stacked in sequence, and the brightness enhancement film assembly and the light-emitting layer are bonded together by a second adhesive layer.

[0009] An electronic device comprises a housing and the display device described above, wherein the display device is mounted on the housing.

[0010] The technical solution adopted in this application can achieve the following beneficial effects: In the present application, since the maximum wavelength of the first operating band is less than 555nm and the maximum wavelength of the second operating band is greater than 555nm, that is, both operating bands avoid the wavelengths to which the human eye has the highest brightness response, that is, the wavelengths to which the human eye is most sensitive. This can effectively reduce the reflectivity of the brightness enhancement film to external light and reduce brightness attenuation at oblique viewing angles. Moreover, since the two different operating bands can correspond to two colors, the mixing of the two colors can ensure that the final reflected hue of the display device is closer to the neutral color, thereby improving the display effect of the display device. Therefore, the brightness enhancement film assembly disclosed in the present application can solve the problem of poor display effect of the display device involved in the related art. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 A schematic cross-sectional view of a display device according to an embodiment of the present application; Figure 2 A schematic diagram of the light path of external light entering the display device disclosed in the embodiment of the present application; Figure 3 This is a schematic diagram of the light path of the light emitted by the light-emitting layer disclosed in the embodiment of the present application.

[0012] Description of reference numerals: 100-brightness enhancing film, 110-first brightness enhancing film, 120-second brightness enhancing film; 200-circular polarizing film; 300-compensation film; 400-luminescent layer. DETAILED DESCRIPTION

[0013] To make the purpose, technical solutions, and advantages of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0014] The brightness enhancement film assembly disclosed in the embodiments of the present application will be described in detail below through specific embodiments and their application scenarios in conjunction with the accompanying drawings.

[0015] Please refer to Figure 1-Figure 3 The present application discloses a brightness enhancement film assembly, which includes at least two brightness enhancement films 100 .

[0016] Please refer to Figure 1 In the present application, the brightness enhancing film 100 is applied to the display device described later. The at least two brightness enhancing films 100 may include a stacked first brightness enhancing film 110 and a second brightness enhancing film 120. The first working band of the first brightness enhancing film 110 is different from the second working band of the second brightness enhancing film 120, that is, the first brightness enhancing film 110 and the second brightness enhancing film 120 can selectively reflect circularly polarized light of different wavelengths, so that the circularly polarized light of different wavelengths can all be used as brightness enhancing light, thereby improving the display brightness of the display device.

[0017] Specifically, the maximum wavelength of the first working band can be less than 555nm, and the minimum wavelength of the second working band can be greater than 555nm, that is, the first working band and the second working band both avoid light with a wavelength of 555nm, so that the reflected color of the first brightness enhancing film 110 and the reflected color of the second brightness enhancing film 120 respectively cover the two ends of the spectrum. By mixing the two reflected colors, it can be ensured that the final reflected color of the display device is closer to the neutral color, thereby improving the display effect of the display device.

[0018] Furthermore, while ensuring that the final hue is neutral, the 555nm wavelength of light is not within the first operating band of the first brightness enhancement film 110 and the second operating band of the second brightness enhancement film 120. Figure 2 In the right area of ​​, when external light is irradiated onto the display device, since the display device is usually provided with a circular polarization film 200 (specifically the circular polarization film 200 described later), the circular polarization film 200 can be a device that selectively absorbs circularly polarized light of a certain handedness and transmits circularly polarized light of another handedness, that is, the handedness of the circular polarization film 200 is the handedness of the selectively transmitted circular polarized light. For example, when the handedness of the circular polarization film 200 is left-handed, the circular polarization film 200 can absorb right-handed circularly polarized light and transmit left-handed circularly polarized light, that is, left-handed circularly polarized light can pass through the circular polarization film 200. Conversely, when the handedness of the circular polarization film 200 is right-handed, the circular polarization film 200 can absorb left-handed circularly polarized light and transmit right-handed circularly polarized light, that is, right-handed circularly polarized light can pass through the circular polarization film 200.

[0019] Therefore, a portion of the external circularly polarized light corresponding to the wavelength of 555nm can pass through the circularly polarizing film 200 and the brightness enhancing film 100, that is, pass through the circularly polarizing film 200, the first brightness enhancing film 110 and the second brightness enhancing film 120. When this portion of the circularly polarized light is reflected by the light-emitting layer 400 of the display device (specifically the light-emitting layer 400 described later), the handedness of this portion of the circularly polarized light will change, so that after passing through the brightness enhancing film 100, it will be completely absorbed by the circularly polarizing film 200 and cannot return to the air side. It can be seen that this can reduce the reflectivity of the display device to external light to a certain extent.

[0020] In this embodiment, please refer to Figure 3 In the right area of ​​, at a viewing angle perpendicular to the plane where the display device resides, that is, at a normal viewing angle of the display device, when the light emitted by the light-emitting layer 400 passes through the brightness enhancing film 100, since the light corresponding to the 555nm wavelength is not within the first operating band of the first brightness enhancing film 110 and the second operating band of the second brightness enhancing film 120, the first brightness enhancing film 110 and the second brightness enhancing film 120 do not reflect the light corresponding to the 555nm wavelength. In other words, all the light corresponding to the 555nm wavelength can directly pass through the first brightness enhancing film 110 and the second brightness enhancing film 120, thereby ensuring the display effect of the display device. Similarly, at a viewing angle of 30° with the plane where the display device resides, that is, at an oblique viewing angle, since the first brightness enhancing film 110 and the second brightness enhancing film 120 still do not reflect the light corresponding to the 555nm wavelength, in other words, all the light corresponding to the 555nm wavelength can directly pass through the first brightness enhancing film 110 and the second brightness enhancing film 120. This can, to a certain extent, reduce the brightness attenuation of the display device at oblique viewing angles, thereby ensuring the display effect of the display device.

[0021] In addition, since the wavelength of 555nm has the highest brightness response to the human eye, that is, the wavelength to which the human eye is most sensitive, and the display device absorbs all external light corresponding to the wavelength of 555nm, the human eye is not easily stimulated by the reflected light of the display device. At an oblique viewing angle, the user can still observe the light emitted by the light-emitting layer 400 corresponding to the wavelength of 555nm. Therefore, even at an oblique viewing angle, the user can still clearly see the content displayed on the display device.

[0022] In the present application, since the maximum wavelength of the first operating band is less than 555nm and the maximum wavelength of the second operating band is greater than 555nm, both operating bands avoid the wavelengths to which the human eye has the highest brightness response, that is, the wavelengths to which the human eye is most sensitive. This can effectively reduce the reflectivity of the brightness enhancement film 100 to external light and reduce brightness attenuation at oblique viewing angles. Moreover, since the two different operating bands can correspond to two colors, the mixing of the two colors can ensure that the final reflected hue of the display device is closer to the neutral color, thereby improving the display effect of the display device. Therefore, the brightness enhancement film assembly disclosed in the present application can solve the problem of poor display effect of the display device involved in the related art.

[0023] Optionally, the maximum wavelength of the first working band of the first brightness enhancing film 110 can be greater than 545nm, that is, the maximum wavelength of the first working band of the first brightness enhancing film 110 is closer to the wavelength of 555nm, and the minimum wavelength of the second working band of the second brightness enhancing film 120 can be less than 565nm, that is, the minimum wavelength of the second working band of the second brightness enhancing film 120 is closer to the wavelength of 555nm.

[0024] In another embodiment, the maximum wavelength of the first operating band can be less than or equal to 545 nm, so that the maximum wavelength of the first operating band of the first brightness enhancing film 110 is relatively far from the wavelength of 555 nm. This can further reduce the reflectivity of external light. The first brightness enhancing film 110 can also avoid reflecting most light of different wavelengths near the wavelength of 555 nm (e.g., between 546 nm and 555 nm), further reducing brightness attenuation at off-angle viewing angles, thereby improving the display quality of the display device. At the same time, the minimum wavelength of the first operating band can be less than or equal to 465 nm, so that the first operating band of the first brightness enhancing film 110 can effectively cover blue light (generally around 460 nm). That is, the first operating band covers the wavelength of blue light. This allows the first brightness enhancing film 110 to reflect more blue light, thereby serving as brightening light. In other words, the proportion of blue light in the brightening light is higher, thereby reducing the power consumption of the display device for blue light at the same brightness. In other words, the power consumption of the display device is lower.

[0025] In this embodiment, the minimum wavelength of the second operating band can be greater than or equal to 565nm, so that the minimum wavelength of the second operating band of the second brightness enhancing film 120 is relatively far away from the wavelength of 555nm, which can further reduce the reflectivity of external light, and the second brightness enhancing film 120 can avoid reflecting most light of different wavelengths near the wavelength of 555nm (for example, between 556nm and 564nm), further reducing the brightness attenuation at oblique viewing angles and improving the display effect of the display device. At the same time, the maximum wavelength of the second operating band can be greater than or equal to 615nm, so that the second operating band of the second brightness enhancing film 120 can effectively cover red light (generally around 620nm), that is, the second operating band covers the wavelength of red light, which causes the second brightness enhancing film 120 to reflect more red light, thereby serving as brightening light, that is, the proportion of red light in the brightening light is also higher, thereby reducing the power consumption of the display device for red light at the same brightness, that is, the power consumption of the display device is lower. In summary, the overall power consumption of the display device is lower.

[0026] Optionally, the brightness enhancement film assembly provided in the embodiments of the present application is described in detail below in combination with three embodiments and seven comparative examples: The difference between Example 1, Example 2 and Example 3 is that the selected first working bands are different, and the selected second working bands are different, but the maximum wavelength of each first working band, that is, the upper limit of each first working band is not higher than 545nm, and the minimum wavelength of each first working band, that is, the lower limit of each first working band is not higher than 465nm. That is, this application does not impose specific restrictions on the specific values ​​of each first working band in Example 1, Example 2 and Example 3, as long as the upper limit of each first working band is not higher than 545nm m, the lower limit of each first working band is not higher than 465nm; similarly, the maximum wavelength of each second working band, that is, the upper limit of each second working band, is not lower than 615nm, and the minimum wavelength of each second working band, that is, the lower limit of each second working band is not lower than 565nm. That is, this application does not impose specific restrictions on the specific values ​​of each second working band in Example 1, Example 2 and Example 3, as long as the upper limit of each second working band is not lower than 615nm and the lower limit of each second working band is not lower than 565nm.

[0027] Comparative Example 1: The difference between this embodiment and Comparative Example 1 is that Comparative Example 1 only uses the first brightness enhancement film 110 of the present application.

[0028] Comparative Example 2: The difference between this embodiment and Comparative Example 2 is that Comparative Example 2 only uses the second brightness enhancement film 120 of the present application.

[0029] Comparative Example 3: The difference between this embodiment and Comparative Example 3 is that Comparative Example 3 only uses the third brightness enhancement film, and the upper limit of the third working band of the third brightness enhancement film is greater than or equal to 615nm, and the lower limit of the third working band is less than or equal to 465nm.

[0030] Comparative Example 4: The difference between this embodiment and Comparative Example 4 is that, in addition to the second brightness enhancing film 120 of the present application, Comparative Example 4 also uses a fourth brightness enhancing film, and the upper limit of the fourth working band of the fourth brightness enhancing film is greater than 545nm, and the lower limit of the fourth working band is less than or equal to 465nm.

[0031] Comparative Example 5: The difference between this embodiment and Comparative Example 5 is that, in addition to the second brightness enhancing film 120 of the present application, Comparative Example 5 also uses a fifth brightness enhancing film, and the upper limit of the fifth working band of the fifth brightness enhancing film is less than or equal to 545 nm, and the lower limit of the fifth working band is greater than 465 nm.

[0032] Comparative Example 6: The difference between this embodiment and Comparative Example 6 is that, in addition to the first brightness enhancing film 110 of the present application, Comparative Example 6 also uses a sixth brightness enhancing film, and the upper limit of the sixth working band of the sixth brightness enhancing film is less than 615nm, and the lower limit of the sixth working band is greater than or equal to 565nm.

[0033] Comparative Example 7: The difference between this embodiment and Comparative Example 7 is that, in addition to the first brightness enhancing film 110 of the present application, Comparative Example 7 also uses a seventh brightness enhancing film, and the upper limit of the seventh working band of the seventh brightness enhancing film is greater than or equal to 615nm, and the lower limit of the seventh working band is less than 565nm.

[0034] This application conducts simulations based on optical simulation software for Examples 1 to 3 and Comparative Examples 1 to 7. In the simulation model, the light-emitting layer 400 is assumed to be divided into an opening area where the light-emitting pixels are located and a non-opening area. The opening area is the light-emitting area of ​​the light-emitting layer 400, and the non-opening area is the non-light-emitting area of ​​the light-emitting layer 400. The light reflectivity of the opening area is 50%, and the non-opening area is completely absorbed. The proportion of the opening area is 20%. The simulation is divided into a simulation of external light reflection at a normal viewing angle and a simulation of brightness attenuation at an oblique viewing angle. The oblique viewing angle is specifically a 30-degree viewing angle. That is, the angle between the line of sight and the thickness direction of the brightness enhancement film 100 is 30 degrees.

[0035] In the simulation of external light reflection at a normal viewing angle, i.e., in the simulation of measuring the reflectivity of the display device to external light, the external light is incident from the air side above the circular polarizing film 200. Since the brightness enhancement film 100 has a semi-transmissive and semi-reflective effect, the light has multiple paths. For details, please refer to Figure 2 .

[0036] Path 1: Please refer to Figure 2 In the right area, since the wavelength corresponding to this part of the external light is not in the brightness enhancing film 100, that is, it is not within the first working band of the first brightness enhancing film 110 and the second working band of the second brightness enhancing film 120, this part of the external light is absorbed by the circular polarizing film 200 after passing through the circular polarizing film 200 and the brightness enhancing film 100, and the other part of the external light is reflected by the light-emitting layer 400 after passing through the brightness enhancing film 100, and the handedness changes, so that it passes through the brightness enhancing film 100 and is finally absorbed by the circular polarizing film 200, which can reduce the reflectivity of the external light.

[0037] Path 2: Please refer to Figure 2 In the left area, part of the external light passes through the circular polarizing film 200 and the brightness enhancing film 100 and is reflected by the light-emitting layer 400, and then is reflected by the brightness enhancing film 100 and the light-emitting layer 400 in sequence, and then passes through the brightness enhancing film 100 and the circular polarizing film 200 in sequence and is emitted. In this path, the light is reflected multiple times, and part of the light is absorbed during the multiple reflections, which can also reduce the reflectivity of the external light to a certain extent.

[0038] In the slant angle brightness attenuation simulation, since the light changes in the normal angle brightness attenuation simulation and the slant angle brightness attenuation simulation are basically the same, this application takes the normal angle brightness attenuation simulation as an example. For details, please refer to Figure 3In the right area, the self-luminescence of the light-emitting layer 400 is non-polarized light, which is incident upward on the brightness enhancement film 100. Since the wavelength corresponding to the part of the light emitted by the light-emitting layer 400 is not within the first working band of the first brightness enhancement film 110 and the second working band of the second brightness enhancement film 120, this part of the light can directly pass through the brightness enhancement film 100 and the circular polarization film 200 in sequence and emit; and the wavelength corresponding to the part of the light emitted by the light-emitting layer 400 is within the first working band of the first brightness enhancement film 110 and the second working band of the second brightness enhancement film 120, please refer to Figure 3 In the left area, this part of the light is reflected by the brightness enhancement film 100 and then reflected by the light emitting layer 400, and then sequentially passes through the brightness enhancement film 100 and the circular polarization film 200 and is emitted.

[0039] In the simulation model, the spectrum of the incident light in the simulation of external light reflection at a normal viewing angle is the D65 spectrum, and the brightness value of the outgoing light divided by the brightness value of the incident light is defined as the reflectivity. The self-luminous spectrum of the light-emitting layer 400 in the brightening simulation is defined to include a blue light part, a green light part, and a red light part, and the central wavelength of the blue light part ranges from 450nm to 470nm, the central wavelength of the green light part ranges from 520nm to 540nm, the central wavelength of the red light part ranges from 610nm to 630nm, and the half-height width is normally distributed between 20nm and 30nm. The simulation results of Examples 1 to 3 and Comparative Examples 1 to 7 are shown in Table 1 below. According to the simulation results, it can be concluded that the solutions provided in Examples 1 to 3 of the present application have a lower brightness attenuation when viewed at a 30° oblique viewing angle, that is, the light output rate at the oblique viewing angle is higher, so that the solutions provided in Examples 1 to 3 of the present application have better visibility when viewed at an oblique viewing angle.

[0040] Specifically, in the simulation results in Table 1 below, the hue values ​​corresponding to neutral colors, i.e., chromaticity indices u'=0.198 and v'=0.468, are shown. Since the hue values ​​u' and v' in Examples 1 to 3 are all relatively close to 0.198 and 0.468, respectively, the final reflected hue of the display device of the present application is closer to neutral colors. Furthermore, since Examples 1 to 3, i.e., the brightness enhancement film 100 of the present application, exhibits relatively low reflectivity to external light and relatively low brightness attenuation at oblique viewing angles, this ensures the display quality of the display device. Furthermore, the power consumption reduction is relatively significant, i.e., the power consumption of the display device is relatively low.

[0041] Table 1 Simulation results are as follows:

[0042] In the present application, the handedness of the circularly polarized light reflected by the first brightness enhancing film 110 and the handedness of the circularly polarized light reflected by the second brightness enhancing film 120 can be the same, that is, the handedness of the circularly polarized light selectively reflected by the first brightness enhancing film 110 and the handedness of the circularly polarized light selectively reflected by the second brightness enhancing film 120 can be the same. In other words, the handedness of the first brightness enhancing film 110 and the second brightness enhancing film 120 are the same as the handedness of the circularly polarized light selectively reflected by the first brightness enhancing film 110 and the second brightness enhancing film 120, so that the first brightness enhancing film 110 and the second brightness enhancing film 120 are the same. The brightening films 120 can selectively reflect left-handed circularly polarized light or right-handed circularly polarized light. Specifically, the materials made of the first brightness enhancing film 110 and the second brightness enhancing film 120 can both be liquid crystal materials, specifically, they are made of cholesteric rod-shaped liquid crystal polymers with a twisted orientation in the thickness direction. Since the molecular arrangement of the cholesteric rod-shaped liquid crystal presents a unique spiral structure, the spiral structure has chirality, that is, it can be right-handed or left-handed, which makes the first brightness enhancing film 110 and the second brightness enhancing film 120 can be right-handed or left-handed.

[0043] In this embodiment, the handedness of the first brightness enhancing film 110 and the handedness of the second brightness enhancing film 120 determine their optical properties, so that the first brightness enhancing film 110 and the second brightness enhancing film 120 can both selectively reflect left-handed circularly polarized light or right-handed circularly polarized light. For example, when the handedness of the first brightness enhancing film 110 and the second brightness enhancing film 120 are both right-handed, the first brightness enhancing film 110 and the second brightness enhancing film 120 can both reflect right-handed circularly polarized light of a specific wavelength and transmit left-handed circularly polarized light of a specific wavelength. When the handedness of the first brightness enhancing film 110 and the second brightness enhancing film 120 are both left-handed, the first brightness enhancing film 110 and the second brightness enhancing film 120 can both reflect left-handed circularly polarized light of a specific wavelength and transmit right-handed circularly polarized light of a specific wavelength, and the light reflected by the first brightness enhancing film 110 and the second brightness enhancing film 120 can be used as brightening light.

[0044] And the handedness of the first brightness enhancing film 110 and the handedness of the second brightness enhancing film 120 can be kept matched with the handedness of the circular polarizing film 200. Specifically, the handedness of the first brightness enhancing film 110 and the handedness of the second brightness enhancing film 120 are opposite to the handedness of the circular polarizing film 200, that is, the handedness of the circularly polarized light selectively reflected by the first brightness enhancing film 110 and the handedness of the circularly polarized light selectively reflected by the second brightness enhancing film 120 are opposite to the handedness of the circularly polarized light selectively transmitted by the circular polarizing film 200. In other words, the handedness of the first brightness enhancing film 110 and the handedness of the second brightness enhancing film 120 are opposite to the handedness of the circularly polarized light selectively transmitted by the circular polarizing film 200, that is, the circularly polarized light passing through the circular polarizing film 200 can all pass through the first brightness enhancing film 110 and the second brightness enhancing film 120. Of course, in other embodiments, in a direction perpendicular to the thickness direction of the brightness enhancing film 100, the handedness of the circularly polarized light reflected by the majority of the regions of the first brightness enhancing film 110 and the handedness of the circularly polarized light reflected by the majority of the regions of the second brightness enhancing film 120 may be the same, while the handedness of the circularly polarized light reflected by the minority of the regions of the first brightness enhancing film 110 and the handedness of the circularly polarized light reflected by the minority of the regions of the second brightness enhancing film 120 may be different.

[0045] Optionally, the first brightness enhancement film 110 and the second brightness enhancement film 120 may be connected by heat sealing. Specifically, the first brightness enhancement film 110 and the second brightness enhancement film 120 are melted by heat and bonded together by heat sealing.

[0046] In another embodiment, the first brightness enhancement film 110 and the second brightness enhancement film 120 may be bonded together via a first adhesive layer. Using the first adhesive layer to bond the first brightness enhancement film 110 and the second brightness enhancement film 120 is relatively efficient and convenient.

[0047] Optionally, the first adhesive layer may be a photosensitive adhesive, a water-based adhesive, or a pressure-sensitive adhesive, so that the first adhesive layer has a relatively good waterproof effect and is not likely to damage the structure of the first brightness enhancement film 110 and the second brightness enhancement film 120. Of course, in other embodiments, the first adhesive layer may be an optical glass adhesive.

[0048] The first brightness enhancing film 110 may have a first ordinary refractive index and a first non-trivial refractive index, and the second brightness enhancing film 120 may have a second ordinary refractive index and a second non-trivial refractive index, the ordinary refractive index refers to the refractive index when the vibration direction of the light wave electric vector is perpendicular to the liquid crystal director, and the non-trivial refractive index refers to the refractive index when the vibration direction of the light wave electric vector is parallel to the liquid crystal director. And according to the foregoing content, it can be seen that since the molecular arrangement of the cholesteric rod-shaped liquid crystal presents a unique spiral structure, this makes the first brightness enhancing film 110 and the second brightness enhancing film 120 both have a spiral structure, and then the spiral structure of the first brightness enhancing film 110 and the spiral structure of the second brightness enhancing film 120 both have a certain pitch. Specifically, the first brightness enhancing film 110 may have a first pitch, and the second brightness enhancing film 120 may have a second pitch.

[0049] Since the working band of the brightness enhancing film 100 can be obtained by multiplying the refractive index of the brightness enhancing film 100 by the pitch, in order to ensure that the wavelengths corresponding to the first working band of the first brightness enhancing film 110 are all smaller than the wavelengths corresponding to the second working band of the second brightness enhancing film 120, optionally, in this embodiment, the first ordinary refractive index and the second ordinary refractive index can be different, the first non-trivial refractive index and the second non-trivial refractive index can also be different, and the first ordinary refractive index is smaller than the second ordinary refractive index, and the first non-trivial refractive index is smaller than the second non-trivial refractive index. At the same time, the first pitch can be less than or equal to the second pitch, so as to ensure that the first working band of the first brightness enhancing film 110 is different from the second working band of the second brightness enhancing film 120, and that the wavelengths corresponding to the first working band of the first brightness enhancing film 110 are all smaller than the wavelengths corresponding to the second working band of the second brightness enhancing film 120. Of course, in other embodiments, when the first trivial refractive index is smaller than the second trivial refractive index and the first non-trivial refractive index is smaller than the second non-trivial refractive index, the first pitch may be slightly larger than the second pitch, as long as the wavelengths corresponding to the first operating band of the first brightness enhancing film 110 are all smaller than the wavelengths corresponding to the second operating band of the second brightness enhancing film 120.

[0050] Alternatively, in another embodiment, the first trivial refractive index may be equal to or greater than the second trivial refractive index, the first non-trivial refractive index may be equal to or greater than the second non-trivial refractive index, and the first pitch may be smaller than the second pitch, so as to ensure that the first operating band is different from the second operating band, and that the wavelengths corresponding to the first operating band of the first brightness enhancing film 110 are smaller than the wavelengths corresponding to the second operating band of the second brightness enhancing film 120.

[0051] Optionally, the first pitch may include a first maximum pitch and a first minimum pitch, the second pitch may include a second maximum pitch and a second minimum pitch, and the first maximum pitch and the first minimum pitch may both be smaller than the second maximum pitch and the second minimum pitch. The first maximum pitch and the first minimum pitch may be the same or different. When the first maximum pitch and the first minimum pitch are the same, the pitch of the first brightness enhancing film 110 is a uniform pitch. When the first maximum pitch and the first minimum pitch are different, the pitch of the first brightness enhancing film 110 is a gradient pitch. Similarly, the second maximum pitch and the second minimum pitch may be the same or different. When the second maximum pitch and the second minimum pitch are the same, the pitch of the second brightness enhancing film 120 is a uniform pitch. When the second maximum pitch and the second minimum pitch are different, the pitch of the second brightness enhancing film 120 is a gradient pitch.

[0052] Optionally, in this embodiment, the operating wavelength band of the brightness enhancement film 100 can be approximately considered to be 2×no λ ×p min ~2×ne λ ×p max Where neλ and noλ are the non-trivial refractive index and the ordinary refractive index of the brightness enhancement film 100 at a wavelength of λnm. Specifically, for the calculation of the first working band of the first brightness enhancement film 110, ne can be the first non-trivial refractive index, no can be the first ordinary refractive index, and p min Can be the first minimum pitch, p max It can be the first maximum pitch, λ can be selected from the wavelength near the first working band for approximate calculation, for example, 500nm can be selected; for the calculation of the second working band of the second brightness enhancement film 120, ne can be the second non-trivial refractive index, no can be the second trivial refractive index, p min Can be the second minimum pitch, p max It can be the second maximum pitch, and λ can be approximately calculated by selecting a wavelength near the second operating band, for example, 600 nm. Of course, this application does not impose any specific limitation on this.

[0053] Optionally, since the brightness enhancing film assembly disclosed in the present application includes at least two brightness enhancing films 100, that is, it can include multiple brightness enhancing films 100, the operating bands of each brightness enhancing film 100 can be different. Specifically, the present application can adjust different brightness enhancing films 100 by adjusting the refractive index (such as the above-mentioned non-trivial refractive index and ordinary refractive index) and pitch (such as the above-mentioned first pitch and second pitch) of each brightness enhancing film 100, thereby obtaining different operating bands.

[0054] Optionally, the present application also discloses an optical film group, including a circular polarizing film 200 and the brightness enhancing film assembly described above. In the thickness direction of the optical film group, the circular polarizing film 200 and the brightness enhancing film assembly can be stacked in sequence, and the handedness of the circularly polarized light reflected by the first brightness enhancing film 110 and the handedness of the circularly polarized light reflected by the second brightness enhancing film 120 are opposite to the handedness of the circularly polarized light transmitted by the circular polarizing film 200, that is, the handedness of the circularly polarized light selectively reflected by the first brightness enhancing film 110 and the handedness of the circularly polarized light selectively reflected by the second brightness enhancing film 120 are opposite to the handedness of the circularly polarized light selectively transmitted by the circular polarizing film 200. In other words, the handedness of the first brightness enhancing film 110 and the handedness of the second brightness enhancing film 120 are opposite to the handedness of the circularly polarized light selectively transmitted by the circular polarizing film 200, so that the circularly polarized light passing through the circular polarizing film 200 can all pass through the first brightness enhancing film 110 and the second brightness enhancing film 120.

[0055] In this embodiment, the circular polarizing film 200 can be the same as the above-mentioned circular polarizing film 200. The circular polarizing film 200 can absorb circularly polarized light with a chirality opposite to its own. The circular polarizing film 200 can include a linear polarizer and a phase difference film. The linear polarizer can be formed by dyeing a polymer stretched film with iodine ions or by coating anisotropic dye liquid crystals. The phase difference film can be formed by stretching or liquid crystal coating.

[0056] Optionally, the optical film assembly may further include a compensation film 300. In the thickness direction of the optical film assembly, the circular polarizing film 200, the compensation film 300, and the brightness enhancement film assembly may be stacked in sequence. The compensation film 300 can compensate for the phase difference of the brightness enhancement film 100 at an oblique viewing angle. The compensation film 300 ensures that light outside the operating band of the brightness enhancement film 100 does not change its polarization state after passing through the brightness enhancement film 100 and the compensation film 300 at an oblique viewing angle, thereby ensuring that the circular polarizing film 200 can completely absorb the light passing through the brightness enhancement film 100 and the compensation film 300, thereby reducing the reflectivity at an oblique viewing angle. The compensation film 300 provided in the embodiment of the present application can reduce the reflectivity of external light and improve the oblique viewing angle integrated black. Optionally, the compensation film 300 can be made of a vertically aligned rod-shaped liquid crystal polymer film. Of course, in other embodiments, the optical film assembly may also not include the compensation film 300.

[0057] Optionally, the present application further discloses a display device comprising a light-emitting layer 400 and the optical film assembly described above. In the thickness direction of the display device, the optical film assembly and the light-emitting layer 400 are stacked in sequence, and the brightness enhancement film assembly and the light-emitting layer 400 can be bonded together by a second adhesive layer. Optionally, the second adhesive layer can be a photosensitive adhesive, a water-based adhesive, or a pressure-sensitive adhesive, that is, the material of the second adhesive layer can be the same as the material of the first adhesive layer, or of course, different, and this application does not impose specific restrictions on this. In this embodiment, the light-emitting layer 400 can be the same as the light-emitting layer 400 described above, and the light-emitting layer 400 can be an organic light-emitting device, that is, the light-emitting layer 400 can be a light-emitting pixel.

[0058] Alternatively, the first brightness enhancing film 110 and the second brightness enhancing film 120 may be disposed sequentially in the direction in which the optical film assembly extends toward the light-emitting layer 400, with the first brightness enhancing film 110 being closer to the external environment and the second brightness enhancing film 120 being closer to the light-emitting layer 400. In other words, in this embodiment of the present application, the first brightness enhancing film 110, which has a smaller operating band, may be disposed closer to the external environment, while the second brightness enhancing film 120, which has a larger operating band, may be disposed closer to the light-emitting layer 400, thereby reducing the reflectivity of the display device. Of course, in other embodiments, the second brightness enhancing film 120 and the first brightness enhancing film 110 may be disposed sequentially in the direction in which the optical film assembly extends toward the light-emitting layer 400.

[0059] Optionally, the present application further discloses an electronic device, comprising a housing and the display device described above, wherein the display device is mounted on the housing, and the housing can better protect the display device.

[0060] The above embodiments of this application focus on the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. Considering the simplicity of the text, they will not be repeated here.

[0061] The foregoing is merely an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should all be included within the scope of the claims of the present application.

Claims

1. A brightness enhancement film assembly, characterized in that: The invention comprises at least two brightness enhancing films (100), wherein the at least two brightness enhancing films (100) comprise a first brightness enhancing film (110) and a second brightness enhancing film (120) stacked together, wherein a first working band of the first brightness enhancing film (110) is different from a second working band of the second brightness enhancing film (120), and a maximum wavelength of the first working band is less than 555 nm, and a minimum wavelength of the second working band is greater than 555 nm.

2. The brightness enhancement film assembly according to claim 1, characterized in that: The maximum wavelength of the first working band is less than or equal to 545 nm, the minimum wavelength of the first working band is less than or equal to 465 nm, the maximum wavelength of the second working band is greater than or equal to 615 nm, and the minimum wavelength of the second working band is greater than or equal to 565 nm.

3. The brightness enhancement film assembly according to claim 1, characterized in that: The handedness of the circularly polarized light reflected by the first brightness enhancement film (110) is the same as the handedness of the circularly polarized light reflected by the second brightness enhancement film (120).

4. The brightness enhancement film assembly according to claim 1, characterized in that: The first brightness enhancement film (110) and the second brightness enhancement film (120) are bonded together via a first adhesive layer.

5. The brightness enhancement film assembly according to claim 4, characterized in that: The first adhesive layer is photosensitive adhesive, water-based adhesive or pressure-sensitive adhesive.

6. An optical film assembly, characterized in that: The invention comprises a circular polarizing film (200) and a brightness enhancing film assembly according to any one of claims 1 to 5, wherein the circular polarizing film (200) and the brightness enhancing film assembly are stacked in sequence in the thickness direction of the optical film group, and the handedness of the circularly polarized light reflected by the first brightness enhancing film (110) and the handedness of the circularly polarized light reflected by the second brightness enhancing film (120) are opposite to the handedness of the circularly polarized light transmitted by the circular polarizing film (200).

7. The optical film assembly according to claim 6, wherein: The optical film group further comprises a compensation film (300), and in the thickness direction of the optical film group, the circular polarization film (200), the compensation film (300) and the brightness enhancement film assembly are stacked in sequence.

8. A display device, characterized in that: The invention comprises a light-emitting layer (400) and the optical film assembly according to claim 6 or claim 7, wherein the optical film assembly and the light-emitting layer (400) are stacked in sequence in the thickness direction of the display device, and the brightness enhancement film assembly and the light-emitting layer (400) are bonded together by a second adhesive layer.

9. The display device according to claim 8, wherein In the direction in which the optical film group extends toward the light-emitting layer (400), the first brightness enhancement film (110) and the second brightness enhancement film (120) are arranged in sequence.

10. An electronic device, characterized in that: The invention comprises a housing and the display device according to claim 8 or claim 9, wherein the display device is mounted on the housing.

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