An optical film

Abstract

The present invention proposes an optical film, the body of which comprises a quarter-wave plate functional layer, a first bonding layer, a polarizing functional layer, and a second bonding layer; the quarter-wave plate functional layer, the first bonding layer, the polarizing functional layer, and the second bonding layer are sequentially bonded layer by layer. The optical film also comprises a plurality of extensions; the hierarchical structure of the extensions is identical to that of the optical film body and is connected to the optical film body. The optical film effectively improves the interception rate of circularly polarized light and the transmittance of natural light. When the optical film is attached to the surface of an optical sensor, it effectively improves the performance of the optical sensor and the ID effect.

Description

Technical Field

[0001] The invention provides an optical film, belonging to the technical field of optical devices. Background Art

[0002] In recent years, mobile phones have gradually shifted towards full-screen displays, and the display area has gradually taken up the entire screen area, resulting in a lack of suitable placement for optical sensors. Optical sensors are primarily used to collect the brightness or color temperature of the phone's external ambient light. The brightness or color temperature of the phone screen is then adjusted to reduce power consumption and improve the user experience. In the past two years, several technologies have been proposed to place optical sensors at the bottom of OLED screens, but performance has consistently been poor. One approach is to place the sensor directly at the bottom of the OLED to collect external ambient light. Another approach is to place the sensor in the non-screen area of ​​the OLED, which offers better accuracy but affects the design and can result in poor ID. Summary of the Invention

[0003] The present invention provides an optical film to solve the problem that the solution of placing the optical sensor directly under the screen in existing mobile phones leads to poor performance, and the solution of placing the sensor outside the screen leads to poor ID. The technical solution adopted is as follows:

[0004] An optical film, the sheet body of which comprises a quarter wave plate functional layer, a first bonding layer, a polarizing functional layer and a second bonding layer; the quarter wave plate functional layer, the first bonding layer, the polarizing functional layer and the second bonding layer are bonded layer by layer in sequence.

[0005] Furthermore, the slow axis direction of the quarter wave plate functional layer is parallel to the absorption axis direction of the polarizing functional layer.

[0006] Furthermore, the first laminating layer and the second laminating layer are both PSA pressure-sensitive adhesive layers.

[0007] Furthermore, the polarizing functional layer includes a first triacetate cellulose film, a polarizing layer and a second triacetate cellulose film; the polarizing functional layer includes a first triacetate cellulose film, a polarizing layer and a second triacetate cellulose film laminated layer by layer in sequence.

[0008] Furthermore, the upper surface of the first triacetate film is bonded to the lower surface of the first bonding layer; and the lower surface of the second triacetate film is bonded to the upper surface of the second bonding layer.

[0009] Furthermore, the membrane thickness of the triacetate cellulose membrane 1 and the triacetate cellulose membrane 2 is obtained by the following formula:

[0010]

[0011] Wherein, L represents the thickness of the triacetate film; L0 represents the unit film thickness of the triacetate film, and the unit film thickness of the triacetate film is 0.01 mm; A0 represents the unit film transmittance corresponding to the unit film thickness of the triacetate film; λ i represents the wavelength of incident natural light; n represents the amount of mixed light in natural light; f(λ i ) represents the wavelength λ i The incident energy of natural light; T s (λ i ) represents the wavelength λ i The transmittance of natural light on triacetate film.

[0012] Furthermore, the optical film is also provided with a plurality of extensions; the hierarchical structure of the plurality of extensions is the same as the hierarchical structure of the sheet body of the optical film, and is connected to the sheet body of the optical film; the mating edges of two adjacent extensions 5 of the extensions adopt arc edges with the same direction and the same curvature.

[0013] Furthermore, the lower surface of the second laminating layer 4 includes a laminating area 1 and a laminating area 2;

[0014] The first laminating area is a circular area with the center point of the second laminating layer as the center and half the radius of the second laminating layer as the radius;

[0015] The second bonding area is the entire area between the edge of the first bonding area and the edge of the second bonding layer.

[0016] Furthermore, the roughness of the lower surface of the extension body is greater than the roughness of the first bonding area and less than the roughness of the second bonding area; and the relationship between the roughness of the first bonding area, the second bonding area, and the extension body and the adhesive force satisfies the following conditions:

[0017] The product of the roughness value of the laminating area 1 and its own adhesive strength value is less than 1820 and greater than 1560;

[0018] The product of the roughness value of the second laminating area and its own adhesive strength value is less than 1340 and greater than 1150;

[0019] The product of the roughness value of the extended body and its own adhesion value is less than 1780 and greater than 1610.

[0020] Furthermore, the thickness of the first laminating layer and the second laminating layer is obtained by the following formula:

[0021]

[0022] Wherein, D represents the thickness of the laminating layer; D0 represents the unit film thickness of the laminating layer, and the laminating layer adopts a PSA pressure-sensitive adhesive layer, and the unit film thickness of the PSA pressure-sensitive adhesive layer is 0.01 mm; B0 represents the unit film transmittance corresponding to the unit film thickness of the laminating layer; λ i represents the wavelength of incident natural light; n represents the amount of mixed light in natural light; f(λ i ) represents the wavelength λ i The incident energy of natural light; T p (λ i ) represents the wavelength λ i The transmittance of natural light on the bonding layer.

[0023] Beneficial effects of the present invention:

[0024] The proposed optical film utilizes the slow axis of a quarter-wave plate and the absorption axis of a polarizer to intercept circularly polarized light while transmitting natural light. Furthermore, by adding a PSA colloid beneath the polarizing layer, the optical film can be attached to other device surfaces. This optical film effectively improves both the interception rate of circularly polarized light and the transmittance of natural light. Attaching the optical film to the surface of an optical sensor can significantly enhance its performance and ID effectiveness. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of the sheet structure of the optical film of the present invention;

[0026] Figure 2 This is a diagram showing the principle of light path interception of the optical film of the present invention;

[0027] Figure 3 Schematic diagram of the structure of the extension body of the present invention Figure 1 ;

[0028] Figure 4 Schematic diagram of the lower surface area of ​​the second laminating layer of the present invention;

[0029] (1, 1 / 4 wave plate functional layer; 2, first bonding layer; 3, polarizing functional layer; 4, second bonding layer; 5, extension body; 31, triacetate cellulose film 1; 32, polarizing layer; 33, triacetate cellulose film 2; 41, bonding area 1; 42, bonding area 2; 51, bonding edge). DETAILED DESCRIPTION

[0030] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0031] The present invention provides an optical film to solve the problem that the solution of placing the optical sensor directly under the screen in existing mobile phones has poor performance, and the solution of placing the sensor outside the screen leads to poor ID. The technical solution adopted is as follows:

[0032] An optical film, such as Figure 1 As shown, the optical film comprises a quarter-wave plate functional layer 1, a first laminating layer 2, a polarizing functional layer 3, and a second laminating layer 4. The quarter-wave plate functional layer 1, the first laminating layer 2, the polarizing functional layer 3, and the second laminating layer 4 are laminated layer by layer in this order. The slow axis of the quarter-wave plate functional layer 1 is parallel to the absorption axis of the polarizing functional layer 3. Both the first laminating layer 2 and the second laminating layer 4 utilize PSA pressure-sensitive adhesive layers.

[0033] The working principle of the above scheme is as follows: the quarter-wave plate functional layer 1 is bonded to the upper surface of the first bonding layer 2; the first bonding layer 2 is bonded to the upper surface of the polarizing functional layer 3; the polarizing functional layer 3 is bonded to the upper surface of the second bonding layer 4, and the optical film is bonded to the corresponding optical component, such as an optical sensor, through the second bonding layer 4. The optical film utilizes the slow axis of the quarter-wave plate and the absorption axis of the polarizer to intercept circularly polarized light and transmit natural light. At the same time, by adding PSA colloid below the polarizing functional layer, the optical film can be attached to the surface of other devices.

[0034] The technical effect of the above solution is that the optical film proposed in this embodiment can effectively increase the interception rate of circularly polarized light and the transmittance of natural light. When attached to the surface of an optical sensor, the optical film effectively improves the optical sensor's lighting performance, lighting accuracy, and ID effect. Furthermore, the installation location of the optical sensor within the mobile phone is no longer restricted by lighting requirements and performance, increasing the flexibility of the optical sensor's installation within the mobile phone.

[0035] One embodiment of the present invention, as Figure 1 As shown, the polarizing functional layer 3 includes a first triacetate film 31, a polarizing layer 32 and a second triacetate film 33; the polarizing functional layer 3 includes a first triacetate film 31, a polarizing layer 32 and a second triacetate film 33 laminated layer by layer in sequence.

[0036] The upper surface of the first triacetate film 31 is bonded to the lower surface of the first bonding layer 2 ; the lower surface of the second triacetate film 33 is bonded to the upper surface of the second bonding layer 4 .

[0037] The working principle of the above scheme is as follows: Figure 2As shown, when linearly polarized light and circularly polarized light simultaneously enter the polarizing functional layer 3 , the circularly polarized light is intercepted by the polarizing layer 32 after passing through the triacetate film 31 and then through the polarizing layer 32 , while the linearly polarized light can penetrate the polarizing layer 32 .

[0038] The technical effect of the above solution is that the structural setting of the polarizing functional layer can effectively improve the interception rate of circularly polarized light, thereby improving the lighting performance and lighting accuracy of the optical sensor.

[0039] In one embodiment of the present invention, the thickness of the triacetate cellulose membrane 1 31 and the triacetate cellulose membrane 2 33 is obtained by the following formula:

[0040]

[0041] Wherein, L represents the thickness of the triacetate film; L0 represents the unit film thickness of the triacetate film, and the unit film thickness of the triacetate film is 0.01 mm; A0 represents the unit film transmittance corresponding to the unit film thickness of the triacetate film; λ i represents the wavelength of incident natural light; n represents the amount of mixed light in natural light; f(λ i ) represents the wavelength λ i The incident energy of natural light; T s (λ i ) represents the wavelength λ i The transmittance of natural light on triacetate film.

[0042] The working principle of the above scheme is: the thickness of the triacetate cellulose membrane 1 and the triacetate cellulose membrane 2 are calculated respectively by the above formula.

[0043] The technical effect of the above scheme is: by calculating the thickness of the triacetate film 1 and the triacetate film 2, the thickness of the triacetate film corresponding to the required transmittance can be accurately obtained, thereby improving the accuracy of the calculation of the triacetate film thickness, thereby ensuring that the transmittance of the optical film accurately reaches the required transmittance index.

[0044] One embodiment of the present invention, as Figure 3 As shown, the optical film is further provided with a plurality of extension bodies 5; the hierarchical structure of the plurality of extension bodies 5 is the same as the hierarchical structure of the sheet body of the optical film, and is connected to the sheet body of the optical film; the mating edges 51 of two adjacent extension bodies 5 of the extension body 5 adopt arc edges with the same direction and the same curvature.

[0045] Specifically, in this embodiment, four extension bodies 5 are used. The hierarchical structure of the extension bodies 5, from top to bottom, also includes a quarter-wave plate functional layer, a first bonding layer, a polarizing functional layer, and a second bonding layer. The polarizing functional layer also includes a first triacetate film, a polarizing layer, and a second triacetate film. The extension bodies 5 are connected to the optical film body and are evenly distributed around the periphery of the sheet. Furthermore, when the optical film adopts a circular structure, the curved edges on the left and right sides of the extension bodies 5 are arcs corresponding to a 120° arc angle with a radius of 1 / 3 the diameter of the optical film.

[0046] The working principle of the above scheme is as follows: In a mobile phone, the lighting accuracy and performance of the optical sensor are key to adjusting the brightness and color temperature of the mobile phone screen. When the optical film is attached to the optical sensor, due to the deviation of the patch position or the size error between the optical film and the optical sensor (that is, the size of the optical film is smaller than the size of the optical sensor attachment position), there will be a marginal gap between the edges of the two. This will cause circularly polarized light to pass through the gap and be collected by the optical sensor, affecting the performance of the optical sensor. Therefore, a number of extensions are provided on the optical film. When the sheet of the optical film is attached to the optical sensor, if there is a marginal gap at the edge of the attachment position of the optical film sheet and the optical sensor, the marginal gap can be completely filled by the extension, and the part of the extension not used for filling the gap is directly attached to the periphery of the optical sensor photosensitive area.

[0047] Furthermore, when the periphery of the optical sensor's photosensitive area and the edge of the photosensitive area are planar or ridged, the shape, structure, and curvature of the extensions ensure that the opposing sides (i.e., the mating edges) of two adjacent extensions are completely closed and abutted, eliminating any gaps between the optical film and the optical sensor from any angle. The shape, structure, and curvature of the extensions completely prevent the formation of edge gaps or unbonded areas during the bonding process between the optical film and the optical sensor due to structural issues at the edge of the optical sensor's photosensitive area.

[0048] In addition, the closed docking of two adjacent extensions generates a mutually restraining adhesive force in the horizontal direction of the optical film, which effectively prevents the optical film from shifting in position with the optical sensor due to long-term use, thereby improving the stability of the adhesion between the optical film and the optical sensor.

[0049] The technical effect of the above solution is that the shape and size of the extension effectively improve the tightness of the edge fit between the optical film and the optical sensor, effectively preventing edge gaps and unattached areas when the optical film and optical sensor are attached, thereby improving the optical film's circularly polarized light interception performance and comprehensiveness. Furthermore, the shape and size of the extension effectively improve the adhesion and stability of the optical film and the optical sensor, effectively preventing the optical film from shifting or falling off.

[0050] One embodiment of the present invention, as Figure 4 As shown, the lower surface of the second laminating layer 4 includes a laminating area 1 41 and a laminating area 2 42;

[0051] The first laminating area 41 is a circular area with the center point of the second laminating layer 4 as the center and a radius of 1 / 2 of the radius of the second laminating layer 4 as the radius;

[0052] The second bonding area 42 is the entire area between the edge of the first bonding area 41 and the edge of the second bonding layer 4 .

[0053] The roughness of the lower surface of the extension body 5 is greater than the roughness of the bonding area 1 41 and smaller than the roughness of the bonding area 2 42, that is: C1<C3<C2, wherein C1, C2 and C3 represent the surface roughness of the bonding area 1, the bonding area 2 and the lower surface of the extension body respectively.

[0054] Furthermore, the relationship between the roughness and the adhesive force of the first laminating area 41, the second laminating area 42 and the extension body 5 satisfies the following conditions:

[0055] The product of the roughness value of the laminating area 1 41 and its own adhesive strength value is less than 1820 and greater than 1560; that is, 1560<C1<1820;

[0056] The product of the roughness value of the second laminating area 42 and its own adhesive strength value is less than 1340 and greater than 1150; that is, 1150<C2<1340;

[0057] The product of the roughness value of the extension body 5 and its own adhesive force value is less than 1780 and greater than 1610; that is, 1610<C3<1780.

[0058] The working principle of the above scheme is as follows: the lower surface of the second bonding layer is the layer that directly bonds with the optical sensor. During the bonding process, since the photosensitive area of ​​the optical sensor is a smooth surface, bubbles are easily generated during the bonding process, affecting the lighting accuracy and lighting performance. In this embodiment, the lower surface of the second bonding layer 4 is divided into two bonding areas, and the surface roughness of the two bonding areas is different; bonding area 1 is located at the center of the lower surface of the second bonding layer, and bonding area 2 is the lower surface area of ​​the second bonding layer between bonding area 1 and the extension body; since bonding area 1 is the first bonding contact area between the optical film and the optical sensor, its bonding strength and roughness indicators are set so that the bonding strength of bonding area 1 is relatively large, reducing the generation rate of bubbles during the bonding process with the optical sensor and ensuring that bonding area 1 does not have loose bonding problems due to the roughness setting. At the same time, once a laminating bubble appears, the adhesion and roughness index settings of the laminating area 1 can ensure that the bubble can be easily pressed out of the laminating area 1 and into the laminating area 2 without damaging or wrinkling the optical film. At this time, the laminating area 2 has not yet been laminating, so the bubbles generated in the laminating area 1 during the laminating process of the optical film and the optical sensor are successfully eliminated. During the laminating process of the laminating area 2 and the optical sensor, due to the adhesion and roughness index settings, once a bubble is generated, it can be smoothly pressed out without causing damage or wrinkles to the film surface. At the same time, since the roughness of the laminating area 2 is the largest and the roughness and adhesion numerical indexes are the smallest, in order to ensure the stable laminating between the optical film and the optical sensor, the roughness and adhesion indexes of the extensions as described above are set, so that the multiple extensions can strengthen the stable laminating between the optical film and the optical sensor from both the longitudinal adhesion and the planar restraint. Moreover, if bonding bubbles are found in bonding area 1 and / or bonding area 2 after the stretch body has been bonded, the relationship between the surface roughness of bonding area 1, bonding area 2 and the lower surface of the stretch body and the setting of the numerical conditions can ensure that the bonding bubbles are smoothly pressed out area by area without causing damage or wrinkles to the optical film.

[0059] On the other hand, long-term use of the optical sensor can cause the adhesive strength of the lower surface of the second bonding layer to weaken. When this localized adhesive strength weakens to a certain extent, the membrane sheet can partially break away from the optical sensor, generating bubbles. Therefore, the relationship and numerical conditions for the surface roughness of the bonding area 1, bonding area 2, and the lower surface of the extension body described above can completely prevent the formation of bubbles between the membrane sheet and the optical sensor during long-term use.

[0060] The technical effect of the above solution is that the relationship and numerical conditions of the surface roughness of the first and second laminating regions and the lower surface of the extension ensure the secure lamination of the second laminating layer, the extension, and the optical sensor, while also ensuring the smoothness of the optical film surface and preventing bubbles from forming between the optical film and the optical sensor over time.

[0061] In one embodiment of the present invention, the thickness of the first laminating layer 2 and the second laminating layer 4 is obtained by the following formula:

[0062]

[0063] Wherein, D represents the thickness of the laminating layer; D0 represents the unit film thickness of the laminating layer, and the laminating layer adopts a PSA pressure-sensitive adhesive layer, and the unit film thickness of the PSA pressure-sensitive adhesive layer is 0.01 mm; B0 represents the unit film transmittance corresponding to the unit film thickness of the laminating layer; λ i represents the wavelength of incident natural light; n represents the amount of mixed light in natural light; f(λ i ) represents the wavelength λ i The incident energy of natural light; T p (λ i ) represents the wavelength λ i The transmittance of natural light on the bonding layer.

[0064] The working principle of the above scheme is: the thickness of the first laminating layer and the second laminating layer are calculated respectively by the above formula. Specifically, in this embodiment, the thickness of the laminating layer using a PSA pressure-sensitive adhesive layer is calculated.

[0065] The technical effect of the above scheme is: by calculating the thickness of the first bonding layer and the second bonding layer, the thickness of the bonding layer corresponding to the required transmittance can be accurately obtained, thereby improving the accuracy of the calculation of the bonding layer thickness, and thus ensuring that the transmittance of the optical film accurately reaches the required transmittance index.

[0066] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. An optical film, characterized in that: The optical film comprises a quarter wave plate functional layer (1), a first bonding layer (2), a polarizing functional layer (3) and a second bonding layer (4); the quarter wave plate functional layer (1), the first bonding layer (2), the polarizing functional layer (3) and the second bonding layer (4) are bonded layer by layer in sequence; the slow axis direction of the quarter wave plate functional layer (1) is parallel to the absorption axis direction of the polarizing functional layer (3); The optical film is further provided with a plurality of extension bodies (5); the lower surface of the second bonding layer (4) includes a bonding area 1 (41) and a bonding area 2 (42); the roughness of the lower surface of the extension body (5) is greater than the roughness of the bonding area 1 (41) and less than the roughness of the bonding area 2 (42); and the relationship between the roughness of the bonding area 1 (41), the bonding area 2 (42) and the extension body (5) and the adhesive force satisfies the following conditions: The product of the roughness value of the bonding area 1 (41) and its own adhesive strength value is less than 1820 and greater than 1560; The product of the roughness value of the second laminating area (42) and its own adhesive strength value is less than 1340 and greater than 1150; The product of the roughness value of the extension body (5) and its own adhesive force value is less than 1780 and greater than 1610.

2. The optical film according to claim 1, characterized in that: The first laminating layer (2) and the second laminating layer (4) both adopt PSA pressure-sensitive adhesive layers.

3. The optical film according to claim 1, wherein: The polarizing functional layer (3) comprises a first triacetate fiber film (31), a polarizing layer (32) and a second triacetate fiber film (33); the first triacetate fiber film (31), the polarizing layer (32) and the second triacetate fiber film (33) are laminated layer by layer in sequence.

4. The optical film according to claim 3, characterized in that: The upper surface of the first triacetate film (31) is bonded to the lower surface of the first bonding layer (2); the lower surface of the second triacetate film (33) is bonded to the upper surface of the second bonding layer (4).

5. The optical film according to claim 3, characterized in that: The membrane thickness of the triacetate cellulose membrane 1 (31) and the triacetate cellulose membrane 2 (33) is obtained by the following formula: Wherein, L represents the thickness of the triacetate cellulose film; L0 represents the unit film thickness of the triacetate cellulose film, A0 represents the unit film transmittance corresponding to the unit film thickness of the triacetate cellulose film; λ i represents the wavelength of incident natural light; n represents the amount of mixed light in natural light; f(λ i ) represents the wavelength λ i The incident energy of natural light; T s (λ i ) represents the wavelength λ i The transmittance of natural light on triacetate film.

6. The optical film according to claim 1, characterized in that: The hierarchical structure of the plurality of extension bodies (5) is the same as the hierarchical structure of the sheet body of the optical film, and the plurality of extension bodies (5) are connected to the sheet body of the optical film; the abutting edges of two adjacent extension bodies (5) of the extension body (5) adopt arc edges with the same direction and the same curvature.

7. The optical film according to claim 1 or 6, characterized in that: The first bonding area (41) is a circular area with the center point of the second bonding layer (4) as the center and 1 / 2 of the radius of the second bonding layer (4) as the radius; The second bonding area (42) is the entire area between the edge of the first bonding area (41) and the edge of the second bonding layer (4).

8. The optical film according to claim 1, characterized in that: The thickness of the first laminating layer (2) and the second laminating layer (4) is obtained by the following formula: Wherein, D represents the thickness of the laminating layer; D0 represents the unit film thickness of the laminating layer; B0 represents the unit film transmittance corresponding to the unit film thickness of the laminating layer; λ i represents the wavelength of incident natural light; n represents the amount of mixed light in natural light; f(λ i ) represents the wavelength λ i The incident energy of natural light; T p (λ i ) represents the wavelength λ i The transmittance of natural light on the bonding layer.

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