TW202421443A - Bonding structure of curved optical lens and applied optical module thereof - Google Patents

Abstract

A bonding structure of a curved optical lens and an applied optical module thereof are provided. The bonding structure of the curved optical lens includes a curved lens, a composite film and a carrier film. The composite film includes an optical film, a first bonding layer, a functional film and a second bonding layer. The optical film is attached to the surface of the curved lens. The first bonding layer is bonded between the curved lens and the optical film. The functional film is bonded between the optical film and the first bonding layer or one side of the optical film facing away from the curved lens. The second bonding layer is bonded between the functional film and the optical film. The present invention adds the functional film to one side of the optical film to effectively reduce the tensile stress damage of the optical film during the bonding process, thereby reducing the radius of curvature and improving the bonding yield.

Description

Bonding structure of curved optical lens and optical module using the same

The present invention relates to the field of optical lenses, and in particular to a bonding structure of a curved optical lens and an optical module using the same.

Currently, free-form surface lenses have been widely used in a variety of optical systems. The demand for attaching various optical films or adhesives to the bonding structure of curved optical lenses has also increased. The aforementioned optical films can be, for example, polarizers, brightness enhancement films, reflective films, etc. How to ensure the bonding yield of free-form surface products is also a bottleneck that many industry players are struggling to break through.

As shown in FIG. 1 , a conventional optical system includes a display 1 and an optical module 2. The display 1 can emit light as a light source. The optical module 2 is composed of optical elements such as a first optical lens 21, a phase retardation lens 22, a second optical lens 23, a reflective polarizer 24, a linear polarizer 25, and a third optical lens 26. The light output from the display 1 is guided to the human eye after multiple reflections and phase adjustment by the optical module 2, so that the originally long light path is greatly shortened, so that the overall volume of the optical system can be minimized. In the above optical module, the phase retardation film 22 can be attached to the concave surface of the first optical lens 21 or the convex surface of the second optical lens 23, the reflective polarizer 24 can be attached to the concave surface of the second optical lens 23, the linear polarizer 25 can be attached to the convex surface of the third optical lens 26, and a curved optical lens can be used to replace at least one optical lens. Taking the phase retardation sheet 22 as an example, as shown in FIG. 2A , the basic structure of the phase retardation sheet 22 is two layers of TAC (triacetate) film 22a, sandwiching a layer of stretched PVA (polyvinyl alcohol) film 22b, and the surface of the phase retardation sheet 22 is usually covered with a protective film (not shown in the figure). When bonding, the phase retardation sheet 22 is first bonded to the carrier film 27, and then the protective film is torn off, and then the phase retardation sheet 22 is bonded to the concave surface of the first optical lens 21 with an adhesive material 28 such as optical adhesive (OCA) or pressure sensitive adhesive (PSA), or as shown in FIG. 2B , the phase retardation sheet 22 can be bonded to the convex surface of the second optical lens 23 with an adhesive material 28 such as OCA or PSA.

Here, the so-called "neutral plane" is explained. It refers to a plane where the material will not be stretched or compressed during bending, that is, a stress-free area. Therefore, finding the stress center plane as the stress balance point in the structural design can protect the parts of the structure that need the most protection. Figure 3A shows the stress condition of the composite membrane 30 formed by stacking multiple layers of membranes in Figure 2A. When the composite membrane 30 is bent, the upper side is shortened by the pressure, and the lower side is extended by the tension. The cross section between the upper and lower sides is the stress center plane NP. This cross section falls on the PVA film 22b in the middle of the phase delay sheet 22, which neither stretches nor shortens during bending. FIG. 3B shows the stress condition of the composite film 30 formed by stacking multiple layers of films in FIG. 2B. When the composite film 30 is bent, the upper side is stretched by the tensile force, and the lower side is shortened by the compressive force. The cross section between the upper side and the lower side is the stress center plane NP. This cross section also falls on the PVA film 22b in the middle of the phase delay film 22, which neither stretches nor shortens during bending. However, the composite film 30 does not have a stress compensation design, and its curvature radius is often not less than 30 mm, otherwise it will affect the bonding of the optical film and the environmental test yield. The composite film 30 will produce micro cracks that cannot be seen under a microscope. These micro cracks will provide a path for water and oxygen to invade during environmental testing, causing the optical film to warp. Furthermore, if the adhesive itself is not strong enough to fix the adhesives on both sides when the optical film is not at the stress balance point, this phenomenon will be more obviously induced under the high temperature conditions of environmental testing, thereby affecting the production yield.

Therefore, how to improve the bonding structure of curved optical lenses to solve the various deficiencies of the above-mentioned prior arts has become a topic that the relevant industry players are eager to research and develop.

In view of this, the main purpose of the present invention is to provide a bonding structure of curved optical lenses and an optical module using the same, by adding a functional film on one side of the optical film, the tensile stress damage to the optical film during the bonding process can be reduced, and the curvature radius can be reduced, thereby achieving an improvement in the bonding yield.

To achieve the above-mentioned purpose, the present invention provides a bonding structure of a curved optical lens, which includes a curved lens, a composite film sheet and a composite film sheet, wherein the composite film sheet includes an optical film, a first bonding layer, a functional film and a second bonding layer. The optical film is bonded to the surface of the curved lens. The first bonding layer is bonded between the curved lens and the optical film. The functional film is bonded between the optical film and the first bonding layer or to the side of the optical film facing away from the curved lens, and the second bonding layer is bonded between the functional film and the optical film. The carrier film is bonded to the side of the composite film sheet facing away from the curved lens.

According to an embodiment of the present invention, the aforementioned surface is a concave surface, and the functional film is bonded between the optical film and the first bonding layer.

According to an embodiment of the present invention, the aforementioned surface is a convex surface, and the functional film is attached to the side of the optical film facing away from the curved lens.

According to an embodiment of the present invention, the aforementioned optical film is a phase retardation film, a reflective polarizer or a linear polarizer.

According to an embodiment of the present invention, the aforementioned optical film is formed by stacking a plurality of optical films, which are at least one of a phase retardation film, a reflective polarizer, and a linear polarizer, and the optical films are bonded to each other via a third bonding layer.

According to an embodiment of the present invention, the first bonding layer and the second bonding layer are optical adhesive or pressure-sensitive adhesive.

According to an embodiment of the present invention, the in-plane phase difference between the first bonding layer and the second bonding layer is 10-20 nanometers.

According to an embodiment of the present invention, the functional film is composed of at least one film selected from cycloolefin polymer (COP), colorless polyimide (CPI), polycarbonate (PC), polyvinyl alcohol (PVA), polyarylate (PAR), polysulfone (PSU) and polyolefin (PO).

According to an embodiment of the present invention, the thickness of the functional film is 10-100 microns.

According to an embodiment of the present invention, the in-plane phase difference value of the aforementioned functional film is less than 30 nanometers.

According to an embodiment of the present invention, the penetration rate of the functional membrane is greater than 90%.

According to an embodiment of the present invention, the Young's modulus of the aforementioned functional film is less than 3 MPa.

According to an embodiment of the present invention, at least one side of the aforementioned functional film is provided with an anti-reflection coating or a bandpass filter layer.

In addition, the present invention also provides an optical module for receiving light emitted by a display and guiding it into a human eye. The optical module includes a first curved lens, a phase retardation lens, a second curved lens, a reflective polarizer, a linear polarizer and a third curved lens arranged in sequence in front of the display, and the optical module further includes a carrier film, a first bonding layer, a functional film and a second bonding layer configured according to the following conditions (1), (2), (3), (4), (5) or (6): (1) The phase retardation lens is bonded to a side of the first curved lens facing the second curved lens; The carrier film is bonded to a side of the phase retardation lens facing away from the first curved lens; The first bonding layer is bonded between the first curved lens and the phase retardation lens; The functional film is bonded between the phase retardation film and the first bonding layer; and The second bonding layer is bonded between the functional film and the phase retardation film; (2) The phase retardation film is bonded to the side of the second curved lens facing the first curved lens; The carrier film is bonded to the side of the phase retardation film facing away from the second curved lens; The first bonding layer is bonded between the second curved lens and the phase retardation film; The functional film is bonded to the side of the phase retardation film facing away from the second curved lens; and The second bonding layer is bonded between the functional film and the phase retardation film; (3) The reflective polarizer is bonded to the side of the second curved lens facing away from the first curved lens; The carrier film is bonded to the side of the reflective polarizer facing away from the second curved lens; The first bonding layer is bonded between the second curved lens and the reflective polarizer; The functional film is bonded between the reflective polarizer and the first bonding layer; and The second bonding layer is bonded between the functional film and the reflective polarizer; (4) The linear polarizer is bonded to the side of the third curved lens facing the second curved lens; The carrier film is bonded to the side of the linear polarizer facing away from the third curved lens; The first bonding layer is bonded between the third curved lens and the linear polarizer; The functional film is bonded to the side of the linear polarizer facing away from the third curved lens; and The second bonding layer is bonded between the functional film and the linear polarizer; (5) The reflective polarizer and the linear polarizer are bonded to each other by the third bonding layer, and bonded to the side of the second curved lens facing away from the first curved lens; The carrier film is bonded to the side of the linear polarizer facing away from the second curved lens; The first bonding layer is bonded between the second curved lens and the reflective polarizer; The functional film is bonded between the reflective polarizer and the first bonding layer; and The second bonding layer is bonded between the functional film and the reflective polarizer; (6) The reflective polarizer and the linear polarizer are bonded to each other by a third bonding layer, and bonded to the side of the third curved lens facing the second curved lens; The carrier film is bonded to the side of the linear polarizer facing away from the third curved lens; The first bonding layer is bonded between the third curved lens and the linear polarizer; The functional film is bonded to the side of the reflective polarizer facing away from the third curved lens; and The second bonding layer is bonded between the functional film and the reflective polarizer.

According to an embodiment of the present invention, the convex surfaces of the first curved lens, the second curved lens and the third curved lens face the display, and the concave surfaces face the human eye.

According to an embodiment of the present invention, the first bonding layer and the second bonding layer are optical adhesive or pressure-sensitive adhesive.

According to an embodiment of the present invention, the in-plane phase difference between the first bonding layer and the second bonding layer is 10-20 nanometers.

According to an embodiment of the present invention, the functional film is composed of at least one film selected from cycloolefin polymer (COP), colorless polyimide (CPI), polycarbonate (PC), polyvinyl alcohol (PVA), polyarylate (PAR), polysulfone (PSU) and polyolefin (PO).

According to an embodiment of the present invention, the thickness of the functional film is 10-100 microns.

According to an embodiment of the present invention, the in-plane phase difference value of the aforementioned functional film is less than 30 nanometers.

According to an embodiment of the present invention, the penetration rate of the functional membrane is greater than 90%.

According to an embodiment of the present invention, the Young's modulus of the aforementioned functional film is less than 3 MPa.

According to an embodiment of the present invention, at least one side of the aforementioned functional film is provided with an anti-reflection coating or a bandpass filter layer.

Compared with the prior art, the present invention has the following advantages: (1)     The present invention can break through the existing design of composite films for curved surface bonding, which lacks stress compensation and faces the problem that the optical film is easy to warp and peel off, thereby leading to the problem of poor production yield. (2)     The present invention adds a functional film on one side of the optical film in the composite film to adjust the stress balance point, so that the tensile stress damage of the optical film in the bonding process is effectively reduced, and the curvature radius can be reduced, which can improve the bonding and environmental test yield of the optical film, thereby greatly improving the reliability of its products.

The following detailed description is based on specific embodiments to make it easier to understand the purpose, technical content, features and effects of the present invention.

The embodiments of the present invention will be further explained below in conjunction with the relevant drawings. As much as possible, the same reference numerals in the drawings and the specification represent the same or similar components. In the drawings, the shapes and thicknesses may be exaggerated for the sake of simplicity and convenience. It is understood that the components not specifically shown in the drawings or described in the specification are the forms known to those with ordinary knowledge in the relevant technical field. Those with ordinary knowledge in this field can make various changes and modifications based on the content of the present invention.

It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

Please refer to FIG. 4A and FIG. 4B. FIG. 4A is a cross-sectional view of the composite film provided by the first embodiment of the present invention; FIG. 4B is a schematic diagram of the bonding state of the bonding structure of the curved optical lens provided by the first embodiment of the present invention. In this embodiment, the composite film 40 includes an optical film 41, a second bonding layer 42, a functional film 43 and a first bonding layer 44 from top to bottom. As shown in FIG. 4A, before use, the composite film 40 is usually covered with a protective film 45 on its surface for temporary protection. When the bonding process is performed, the protective film 45 is torn off, and as shown in FIG. 4B, the side of the optical film 41 facing away from the functional film 43 is bonded with a carrier film 50, and then the first bonding layer 44 is bonded to the surface of the curved lens 60. In detail, the bonding structure of the curved optical lens of this embodiment includes a curved lens 60 and a composite film 40 bonded to the surface of the curved lens 60, and a carrier film 50 is bonded to the surface of the composite film 40 facing away from the curved lens 60. In this embodiment, the optical film 41 is bonded to the concave surface of the curved lens 60, the first bonding layer 44 is bonded between the curved lens 60 and the optical film 41, the functional film 43 is bonded between the optical film 41 and the first bonding layer 44, and the second bonding layer 42 is bonded between the functional film 43 and the optical film 41.

Please refer to FIG. 5A and FIG. 5B. FIG. 5A is a cross-sectional view of the composite film provided by the second embodiment of the present invention; FIG. 5B is a schematic diagram of the bonding state of the bonding structure of the curved optical lens provided by the second embodiment of the present invention. In this embodiment, the composite film 40 includes a functional film 43, a second bonding layer 42, an optical film 41 and a first bonding layer 44 from top to bottom. As shown in FIG. 5A, the composite film 40 is also covered with a protective film 45 before use, and the protective film 45 is torn off during the bonding process. As shown in FIG. 5B, a carrier film 50 is attached to the side of the functional film 43 facing away from the optical film 41, and then the first bonding layer 44 is attached to the surface of the curved lens 60. In detail, the bonding structure of the curved optical lens of this embodiment includes a curved lens 60 and a composite film 40 bonded to the surface of the curved lens 60, and a carrier film 50 is bonded to the side of the composite film 40 facing away from the curved lens 60. In this embodiment, the optical film 41 is bonded to the convex surface of the curved lens 60, the first bonding layer 44 is bonded between the curved lens 60 and the optical film 41, the functional film 43 is bonded to the side of the optical film 41 facing away from the curved lens 60, and the second bonding layer 42 is bonded between the functional film 43 and the optical film 41.

Furthermore, in some embodiments, the optical film 41 used in the present invention may be a single-layer optical film, for example, the optical film may be a phase retardation film, a reflective polarizer, or a linear polarizer; the optical film 41 may also be formed by stacking a plurality of optical films 41, these optical films 41 may be at least one of a phase retardation film, a reflective polarizer, and a linear polarizer, and these optical films 41 are bonded to each other with a third bonding layer (see the seventh and eighth embodiments).

In some embodiments, the first bonding layer 44 and the second bonding layer 42 used in the present invention may be optical adhesive or pressure-sensitive adhesive. Preferably, the in-plane phase difference (R) of the first bonding layer 44 and the second bonding layer 42 used in the present invention is 10-20 nanometers.

In some embodiments, the functional film 43 used in the present invention may be composed of at least one film selected from cycloolefin polymer (COP), colorless polyimide (CPI), polycarbonate (PC), polyvinyl alcohol (PVA), polyarylate (PAR), polysulfone (PSU) and polyolefin (PO). In some embodiments, the thickness of the functional film 43 used in the present invention is 10-100 microns. It is worth noting that the smaller the in-plane phase difference of the functional film 43 used in the present invention, the better, which is basically less than 30 nanometers, preferably less than 20 nanometers, and can even approach or be equal to 0. The transmittance (T%) of the functional film 43 used in the present invention is greater than 90%. It is also worth mentioning that the Young's modulus of the functional film 43 used in the present invention is as small as possible, and is basically less than 3 MPa, and can even approach 0. In addition, the present invention can be provided with an anti-reflection coating or a bandpass filter layer on at least one side of the functional film 43.

Please refer to FIG. 6, which is a schematic diagram of the layout of the optical module provided by the third to eighth embodiments of the present invention. In the third to eighth embodiments, the optical module 100 is used to receive the light emitted by the display 1 and guide it into the human eye 70 for imaging. The optical module 100 includes a first curved lens 110, a phase retardation lens 120, a second curved lens 130, a reflective polarizer 140, a linear polarizer 150 and a third curved lens 160 arranged in sequence in front of the display 1; wherein the convex surfaces of the first curved lens 110, the second curved lens 130 and the third curved lens 160 face the display 1, and the concave surfaces face the human eye 70. The optical modules 100 of the third to eighth embodiments are further configured with a carrier film 50, a first bonding layer 44, a functional film 43 and a second bonding layer 42 respectively.

Please refer to Figure 7A and Figure 7B. Figure 7A is a schematic diagram of the phase retardation sheet bonded to the first curved lens in the third embodiment of the present invention; Figure 7B is a schematic diagram of the force applied to the composite film including the phase retardation sheet in Figure 7A. In this embodiment, the phase retardation sheet 120 is bonded to the concave surface of the first curved lens 110 to form a whole. As shown in FIG. 7A , the phase retardation film 120 is bonded to the side of the first curved lens 110 facing the second curved lens 130, the carrier film 50 is bonded to the side of the phase retardation film 120 facing away from the first curved lens 110, the first bonding layer 44 is bonded between the first curved lens 110 and the phase retardation film 120, the functional film 43 is bonded between the phase retardation film 120 and the first bonding layer 44, and the second bonding layer 42 is bonded between the functional film 43 and the phase retardation film 120. As shown in FIG. 7B , the phase delay sheet 120 of this embodiment is a layer of stretched PVA film 122 sandwiched between two layers of TAC film 121. When the composite film sheet 40 is bent, the upper side is shortened by pressure, and the lower side is extended by tension, and the cross section between the upper side and the lower side is the stress center plane NP, which neither extends nor shortens during bending. Compared with the prior art in which the stress center plane NP is the PVA film 22b in the middle of the phase delay sheet 22 (see FIG. 3A ), the stress center plane NP of this embodiment moves downward, and the TAC film 121 falling below the PVA film 122 can reduce the tensile stress to which the phase delay sheet 120 is subjected when bending.

Please refer to Figure 8A and Figure 8B. Figure 8A is a schematic diagram of the phase retardation sheet bonded to the second curved lens in the fourth embodiment of the present invention; Figure 8B is a schematic diagram of the force applied to the composite film including the phase retardation sheet in Figure 8A. In this embodiment, the phase retardation sheet 120 is bonded to the convex surface of the second curved lens 130 to form a whole. As shown in FIG. 8A , the phase retardation plate 120 is bonded to the side of the second curved lens 130 facing the first curved lens 110 (see FIG. 6 ), the carrier film 50 is bonded to the side of the phase retardation plate 120 facing away from the second curved lens 130 , the first bonding layer 44 is bonded between the second curved lens 130 and the phase retardation plate 120 , the functional film 43 is bonded to the side of the phase retardation plate 120 facing away from the second curved lens 130 , and the second bonding layer 42 is bonded between the functional film 43 and the phase retardation plate 120 . As shown in FIG. 8B , the phase retardation sheet 120 of this embodiment is a layer of stretched PVA film 122 sandwiched between two layers of TAC film 121. When the composite film sheet 40 is bent, the upper side is stretched by the tensile force, and the lower side is shortened by the compressive force, while the stress center plane NP between the upper side and the lower side is neither stretched nor shortened during bending. Compared with the prior art in which the stress center plane NP is the PVA film 22b in the middle of the phase retardation sheet 22 (see FIG. 3B ), the stress center plane NP of this embodiment moves upward, and the TAC film 121 falls on the PVA film 122, which can reduce the tensile stress on the phase retardation sheet 120 when bending.

Please refer to Figure 9A and Figure 9B. Figure 9A is a schematic diagram of the reflective polarizer being bonded to the second curved lens in the fifth embodiment of the present invention; Figure 9B is a schematic diagram of the force applied to the composite film including the reflective polarizer in Figure 9A. In this embodiment, the reflective polarizer 140 is bonded to the concave surface of the second curved lens 130 to form a whole. As shown in FIG. 9A , the reflective polarizer 140 is bonded to the side of the second curved lens 130 facing away from the first curved lens 110 , the carrier film 50 is bonded to the side of the reflective polarizer 140 facing away from the second curved lens 130 (see FIG. 6 ), the first bonding layer 44 is bonded between the second curved lens 130 and the reflective polarizer 140 , the functional film 43 is bonded between the reflective polarizer 140 and the first bonding layer 44 , and the second bonding layer 42 is bonded between the functional film 43 and the reflective polarizer 140 . As shown in FIG. 9B , when the composite film 40 of this embodiment is bent, the upper side is shortened by pressure, and the lower side is extended by tension, while the stress center plane NP between the upper side and the lower side is neither extended nor shortened during bending. Compared with the stress center plane NP falling in the middle of the optical film (phase delay film 22) in the prior art (see FIG. 3A ), the stress center plane NP of this embodiment moves downward and falls on the second bonding layer 42 below the reflective polarizer 140, which can reduce the tensile stress on the reflective polarizer 140 when it is bent.

Please refer to Figure 10A and Figure 10B. Figure 10A is a schematic diagram of the linear polarizer being bonded to the third curved lens in the sixth embodiment of the present invention; Figure 10B is a schematic diagram of the force applied to the composite film including the linear polarizer in Figure 10A. In this embodiment, the linear polarizer 150 is bonded to the convex surface of the third curved lens 160 to form a whole. As shown in FIG. 10A , the linear polarizer 150 is bonded to the side of the third curved lens 160 facing the second curved lens 130 (see FIG. 6 ), the carrier film 50 is bonded to the side of the linear polarizer 150 facing away from the third curved lens 160 , the first bonding layer 44 is bonded between the third curved lens 160 and the linear polarizer 150 , the functional film 43 is bonded to the side of the linear polarizer 150 facing away from the third curved lens 160 , and the second bonding layer 42 is bonded between the functional film 43 and the linear polarizer 150 . As shown in FIG. 10B , the linear polarizer 150 of this embodiment is a layer of stretched PVA film 152 sandwiched between two layers of TAC film 151. When the composite film 40 is bent, the upper side is stretched by the tensile force, and the lower side is shortened by the compressive force, while the stress center plane NP between the upper side and the lower side is neither stretched nor shortened during bending. Compared with the prior art in which the stress center plane NP is the PVA film 22b in the middle of the phase retardation film 22 (see FIG. 3B ), the stress center plane NP of this embodiment moves upward, and the TAC film 151 falls on the PVA film 152, which can reduce the tensile stress on the linear polarizer 150 when it is bent.

Please refer to Figure 11A and Figure 11B. Figure 11A is a schematic diagram of the reflective polarizer and the linear polarizer bonded to the second curved lens in the seventh embodiment of the present invention; Figure 11B is a schematic diagram of the force applied to the composite film including the reflective polarizer and the linear polarizer in Figure 11A. In this embodiment, the reflective polarizer 140 and the linear polarizer 150 are bonded to the concave surface of the second curved lens 130 to form a whole. As shown in FIG. 11A , the reflective polarizer 140 and the linear polarizer 150 are bonded to each other by a third bonding layer 46 , and are bonded to the side of the second curved lens 130 facing away from the first curved lens 110 (see FIG. 6 ). The carrier film 50 is bonded to the side of the linear polarizer 150 facing away from the second curved lens 130 . The first bonding layer 44 is bonded between the second curved lens 130 and the reflective polarizer 140 . The functional film 43 is bonded between the reflective polarizer 140 and the first bonding layer 44 . The second bonding layer 42 is bonded between the functional film 43 and the reflective polarizer 140 . As shown in FIG. 11B , when the composite film 40 of this embodiment is bent, the upper side is shortened by pressure, and the lower side is extended by tension, while the stress center plane NP between the upper side and the lower side is neither extended nor shortened during bending. Compared with the stress center plane NP in the prior art falling in the middle of the optical film (phase delay film 22) (see FIG. 3A ), which is equivalent to the position of the third bonding layer 46 between the reflective polarizer 140 and the linear polarizer 150 in this embodiment, the stress center plane NP of this embodiment moves downward and falls on the reflective polarizer 140 below the third bonding layer 46, which can reduce the tensile stress on the reflective polarizer 140 and the linear polarizer 150 when bent.

Please refer to Figure 12A and Figure 12B. Figure 12A is a schematic diagram of the eighth embodiment of the present invention in which the reflective polarizer and the linear polarizer are bonded to the third curved lens; Figure 12B is a schematic diagram of the force applied to the composite film including the reflective polarizer and the linear polarizer in Figure 12A. In this embodiment, the reflective polarizer 140 and the linear polarizer 150 are bonded to the convex surface of the third curved lens 160 to form a whole. As shown in FIG. 12A , the reflective polarizer 140 and the linear polarizer 150 are bonded to each other by a third bonding layer 46 , and bonded to the side of the third curved lens 160 facing the second curved lens 130 (see FIG. 6 ). The carrier film 50 is bonded to the side of the linear polarizer 150 facing away from the third curved lens 160 . The first bonding layer 44 is bonded between the third curved lens 160 and the linear polarizer 150 . The functional film 43 is bonded to the side of the linear polarizer 150 facing away from the third curved lens 160 . The second bonding layer 42 is bonded between the functional film 43 and the reflective polarizer 140 . As shown in FIG. 12B , when the composite film 40 of this embodiment is bent, the upper side is stretched by the tensile force, and the lower side is shortened by the compressive force, while the stress center plane NP between the upper side and the lower side is neither stretched nor shortened during bending. Compared with the prior art in which the stress center plane NP is the PVA film 22b in the middle of the phase retardation film 22 (see FIG. 3B ), which is equivalent to the position of the third bonding layer 46 between the reflective polarizer 140 and the linear polarizer 150 in this embodiment, the stress center plane NP of this embodiment moves upward, and the reflective polarizer 140 falls on the third bonding layer 46, which can reduce the tensile stress on the reflective polarizer 140 and the linear polarizer 150 when bending.

Based on the above description, the present invention utilizes a functional film disposed on one side of an optical film including a phase retardation film, a reflective polarizer or/and a linear polarizer. The addition of this functional film helps to adjust the stress balance point in the composite film structure, which can reduce the tensile stress on the optical film during the bonding process, and prevent the optical film from warping and eventually causing detachment or even falling, thereby greatly improving the reliability of the product and extending its service life.

As for the merging of two optical films, the previous technology usually pastes two optical films on two optical lenses respectively, and then assembles the two optical lenses into a semi-finished product. The present invention uses a composite film that combines two optical films with a third bonding layer, which can reduce one step in the bonding process. At the same time, the QC (quality control) of the two optical films can be combined, which can reduce the number of parts and improve the bonding yield.

However, the above is only the preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Therefore, all equivalent changes or modifications based on the features and spirit described in the scope of the present invention should be included in the scope of the patent application of the present invention.

1: Display 2: Optical module 21: First optical lens 22: Phase retardation film 22a: TAC film 22b: PVA film 23: Second optical lens 24: Reflective polarizer 25: Linear polarizer 26: Third optical lens 27: Carrier film 28: Adhesive material 30: Composite film 40: Composite film 41: Optical film 42: Second bonding layer 43: Functional film 44: First bonding layer 45: Protective film 46: Third bonding layer 50: Carrier film 60: Curved lens 70: Human eye 100: Optical module 110: First curved lens 120: Phase retardation film 121: TAC film 122: PVA film 130: Second curved lens 140: Reflective polarizer 150: Linear polarizer 151: TAC film 152: PVA film 160: Third curved lens NP: Stress center plane

FIG. 1 is a schematic diagram of the layout of an optical system provided by the prior art. FIG. 2A and FIG. 2B are schematic diagrams of the bonding conditions of the bonding structures of two curved optical lenses provided by the prior art. FIG. 3A and FIG. 3B are schematic diagrams of the force conditions of the composite membrane in FIG. 2A and FIG. 2B, respectively. FIG. 4A is a cross-sectional view of the composite membrane provided by the first embodiment of the present invention. FIG. 4B is a schematic diagram of the bonding conditions of the bonding structure of the curved optical lens provided by the first embodiment of the present invention. FIG. 5A is a cross-sectional view of the composite membrane provided by the second embodiment of the present invention. FIG. 5B is a schematic diagram of the bonding conditions of the bonding structure of the curved optical lens provided by the second embodiment of the present invention. FIG. 6 is a schematic diagram of the layout of the optical module provided by the third to eighth embodiments of the present invention. FIG. 7A is a schematic diagram of the phase retardation plate bonded to the first curved lens in the third embodiment of the present invention. FIG. 7B is a schematic diagram of the force condition of the composite film containing the phase retardation plate in FIG. 7A. FIG. 8A is a schematic diagram of the phase retardation plate bonded to the second curved lens in the fourth embodiment of the present invention. FIG. 8B is a schematic diagram of the force condition of the composite film containing the phase retardation plate in FIG. 8A. FIG. 9A is a schematic diagram of the reflective polarizer bonded to the second curved lens in the fifth embodiment of the present invention. FIG. 9B is a schematic diagram of the force condition of the composite film containing the reflective polarizer in FIG. 9A. FIG. 10A is a schematic diagram of the linear polarizer bonded to the third curved lens in the sixth embodiment of the present invention. FIG. 10B is a schematic diagram of the force condition of the composite film containing the linear polarizer in FIG. 10A. FIG. 11A is a schematic diagram of the reflective polarizer and the linear polarizer bonded to the second curved lens in the seventh embodiment of the present invention. FIG. 11B is a schematic diagram of the force condition of the composite film containing the reflective polarizer and the linear polarizer in FIG. 11A. FIG. 12A is a schematic diagram of the reflective polarizer and the linear polarizer bonded to the third curved lens in the eighth embodiment of the present invention. FIG. 12B is a schematic diagram of the force condition of the composite film containing the reflective polarizer and the linear polarizer in FIG. 12A.

40: Composite diaphragm

41: Optical film

42: Second bonding layer

43: Functional membrane

44: First bonding layer

50: Carrier film

60: Curved lens

Claims (23)

A bonding structure of a curved optical lens, comprising: a curved lens; a composite film, comprising: an optical film bonded to a surface of the curved lens; a first bonding layer bonded between the curved lens and the optical film; a functional film bonded between the optical film and the first bonding layer or on a side of the optical film facing away from the curved lens; and a second bonding layer bonded between the functional film and the optical film; and a carrier film bonded to a side of the composite film facing away from the curved lens. The bonding structure of the curved optical lens as described in claim 1, wherein the surface is a concave surface, and the functional film is bonded between the optical film and the first bonding layer. The bonding structure of the curved optical lens as described in claim 1, wherein the surface is convex and the functional film is bonded to the side of the optical film facing away from the curved lens. The bonding structure of the curved optical lens as described in claim 1, wherein the optical film is a phase retardation film, a reflective polarizer or a linear polarizer. The bonding structure of the curved optical lens as described in claim 1, wherein the optical film is formed by stacking a plurality of optical films, the optical films are at least one of a phase retardation film, a reflective polarizer and a linear polarizer, and the optical films are bonded to each other by a third bonding layer. The bonding structure of the curved optical lens as described in claim 1, wherein the first bonding layer and the second bonding layer are optical adhesive or pressure-sensitive adhesive. The bonding structure of the curved optical lens as described in claim 1, wherein the in-plane phase difference between the first bonding layer and the second bonding layer is 10-20 nanometers. The bonding structure of the curved optical lens as described in claim 1, wherein the functional film is composed of at least one thin film selected from cycloolefin polymer (COP), colorless polyimide (CPI), polycarbonate (PC), polyvinyl alcohol (PVA), polyarylate (PAR), polysulfone (PSU) and polyolefin (PO). The bonding structure of the curved optical lens as described in claim 1, wherein the thickness of the functional film is 10-100 microns. The bonding structure of the curved optical lens as described in claim 1, wherein the in-plane phase difference of the functional film is less than 30 nanometers. The bonding structure of the curved optical lens as described in claim 1, wherein the transmittance of the functional film is greater than 90%. The bonding structure of the curved optical lens as described in claim 1, wherein the Young's modulus of the functional film is less than 3 MPa. The bonding structure of the curved optical lens as described in claim 1, wherein an anti-reflection coating or a bandpass filter layer is provided on at least one side of the functional film. An optical module is used to receive light emitted by a display and guide it into a human eye. The optical module includes a first curved lens, a phase retardation lens, a second curved lens, a reflective polarizer, a linear polarizer and a third curved lens arranged in sequence in front of the display, and the optical module further includes a carrier film, a first bonding layer, a functional film and a second bonding layer configured according to the following conditions (1), (2), (3), (4), (5) or (6): (1)     The phase retardation lens is bonded to a side of the first curved lens facing the second curved lens; The carrier film is bonded to a side of the phase retardation lens facing away from the first curved lens; The first bonding layer is bonded between the first curved lens and the phase retardation lens; The functional film is bonded between the phase retardation film and the first bonding layer; and The second bonding layer is bonded between the functional film and the phase retardation film; (2)     The phase retardation film is bonded to the side of the second curved lens facing the first curved lens; The carrier film is bonded to the side of the phase retardation film facing away from the second curved lens; The first bonding layer is bonded between the second curved lens and the phase retardation film; The functional film is bonded to the side of the phase retardation film facing away from the second curved lens; and The second bonding layer is bonded between the functional film and the phase retardation film; (3)     The reflective polarizer is bonded to the side of the second curved lens facing away from the first curved lens; The carrier film is bonded to the side of the reflective polarizer facing away from the second curved lens; The first bonding layer is bonded between the second curved lens and the reflective polarizer; The functional film is bonded between the reflective polarizer and the first bonding layer; and The second bonding layer is bonded between the functional film and the reflective polarizer; (4)     The linear polarizer is bonded to the side of the third curved lens facing the second curved lens; The carrier film is bonded to the side of the linear polarizer facing away from the third curved lens; The first bonding layer is bonded between the third curved lens and the linear polarizer; The functional film is bonded to the side of the linear polarizer facing away from the third curved lens; and The second bonding layer is bonded between the functional film and the linear polarizer; (5)     The reflective polarizer and the linear polarizer are bonded to each other by a third bonding layer, and bonded to the side of the second curved lens facing away from the first curved lens; The carrier film is bonded to the side of the linear polarizer facing away from the second curved lens; The first bonding layer is bonded between the second curved lens and the reflective polarizer; The functional film is bonded between the reflective polarizer and the first bonding layer; and The second bonding layer is bonded between the functional film and the reflective polarizer; (6)     The reflective polarizer and the linear polarizer are bonded to each other by a third bonding layer, and bonded to the side of the third curved lens facing the second curved lens; The carrier film is bonded to the side of the linear polarizer facing away from the third curved lens; The first bonding layer is bonded between the third curved lens and the linear polarizer; The functional film is bonded to the side of the reflective polarizer facing away from the third curved lens; and The second bonding layer is bonded between the functional film and the reflective polarizer. An optical module as described in claim 14, wherein the convex surfaces of the first curved lens, the second curved lens, and the third curved lens face the display, and the concave surfaces face the human eye, An optical module as described in claim 14, wherein the first bonding layer and the second bonding layer are optical adhesive or pressure-sensitive adhesive. An optical module as described in claim 14, wherein the in-plane phase difference between the first bonding layer and the second bonding layer is 10-20 nanometers. An optical module as described in claim 14, wherein the functional film is composed of at least one thin film selected from the group consisting of cycloolefin polymer (COP), colorless polyimide (CPI), polycarbonate (PC), polyvinyl alcohol (PVA), polyarylate (PAR), polysulfone (PSU) and polyolefin (PO). An optical module as described in claim 14, wherein the thickness of the functional film is 10-100 microns. An optical module as described in claim 14, wherein the in-plane phase difference of the functional film is less than 30 nanometers. An optical module as described in claim 14, wherein the transmittance of the functional film is greater than 90%. An optical module as described in claim 14, wherein the Young's modulus of the functional film is less than 3 MPa. An optical module as described in claim 14, wherein an anti-reflection coating or a bandpass filter layer is provided on at least one side of the functional film.

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