Detection device for phase difference film and production line

Abstract

The invention discloses a detection device for a phase difference film and a production line, and belongs to the technical field of optical film detection.The production line comprises the detection device for the phase difference film, and the detection device comprises a backlight module, a linear polarization element and a circular polarization element which are sequentially arranged in the first direction; the first direction is used for intersecting with the moving direction of the phase difference film, and the linear polarization element and the circular polarization element are used for being arranged on the two opposite sides of the phase difference film. Light emitted by the phase difference film can be converted into first linearly polarized light through the first phase difference layer of the circular polarization element, and an included angle is formed between the polarization direction of the first linearly polarized light and the polarization direction of the linear polarization layer of the circular polarization element, so that when the phase difference film has defects, the polarization direction of the first linearly polarized light is larger than that of the linear polarization layer. Therefore, the defect area and the qualified area of the phase difference film have different brightness. According to the detection device, the phase difference film can be detected without changing the position of the phase difference film, so that the detection operation of the phase difference film is simplified, and manpower is saved.

Description

Technical Field

[0001] The present application belongs to the technical field of optical film detection, and specifically relates to a detection device and production line for phase difference films. Background Art

[0002] Phase difference films, such as optical compensation films, are usually processed by coating liquid materials on the surface of the substrate. In this processing method, the coating thickness of the liquid, the uniformity of the liquid coating, foreign matter and scratches and other coating conditions will affect the phase difference value of the phase difference film, causing imaging problems in subsequent products. Therefore, in order to ensure the quality of the phase difference film, the phase difference film needs to be tested regularly.

[0003] However, currently, the liquid is usually coated on the substrate while the substrate is driven to move, and then the liquid coated on the substrate is solidified to obtain the desired phase difference film, and the processed phase difference film moves synchronously with the movement of the substrate and is wound on a winding mechanism, such as a winding roller. In this processing method, when the phase difference film needs to be tested, the phase difference film needs to be manually removed from the winding mechanism before the corresponding testing operation can be performed, which makes the testing operation of the phase difference film more complicated and consumes more manpower. Summary of the invention

[0004] The purpose of the embodiments of the present application is to provide a detection device and a production line for a phase difference film, which can solve the problem that the detection operation of the phase difference film in the related art is relatively complicated and consumes a lot of manpower.

[0005] In a first aspect, an embodiment of the present application provides a detection device for a phase difference film, comprising: a backlight module, a linear polarization element, and a circular polarization element sequentially arranged along a first direction, wherein the first direction is used to intersect with the moving direction of the phase difference film, and the linear polarization element and the circular polarization element are used to be arranged on two opposite sides of the phase difference film, and the circular polarization element comprises a first phase difference layer arranged toward the phase difference film and a linear polarization layer arranged away from the phase difference film; Among them, the first phase difference layer and the phase difference film are used to make the light produce opposite rotation directions, and the optical axis direction of the first phase difference layer is perpendicular to the optical axis direction of the phase difference film, so that the light emitted by the phase difference film is converted into a first linear polarized light through the first phase difference layer, and the polarization direction of the first linear polarized light is set at an angle to the polarization direction of the linear polarizing layer, so that when there are defects in the phase difference film, the defective area and the qualified area of ​​the phase difference film have different brightness.

[0006] In a second aspect, an embodiment of the present application provides a production line, which includes a driving mechanism and the detection device described above, wherein the driving mechanism is used to drive the phase difference film to move.

[0007] In an embodiment of the present application, the first phase difference layer of the circular polarizing element can convert the light emitted by the phase difference film into a first linear polarized light, and the polarization direction of the first linear polarized light is set at an angle to the polarization direction of the linear polarizing layer, so that when there are defects in the phase difference film, the defective area and the qualified area of ​​the phase difference film have different brightness, thereby the phase difference film can be detected, and in an embodiment of the present application, the backlight module, linear polarizing element and circular polarizing element of the detection device are arranged along a first direction, and the first direction is used to intersect with the moving direction of the phase difference film. That is to say, the detection device provided in the embodiment of the present application does not need to change the position of the phase difference film, and the phase difference film can be detected in situ while processing the phase difference film, thereby simplifying the detection operation of the phase difference film and saving manpower. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 This is a schematic diagram of the structure of the production line disclosed in the embodiment of the present application; Figure 2 A schematic diagram of the structure of a circular polarizing element disclosed in an embodiment of the present application; Figure 3 This is a schematic diagram of the structure of a detection device disclosed in one of the embodiments of the present application; Figure 4 A schematic diagram of the structure of a detection device disclosed in another embodiment of the present application; Figure 5 A schematic diagram of the arrangement of the substrate layer and the linear polarizing element disclosed in the embodiment of the present application; Figure 6 This is a schematic diagram of the structure of a detection device disclosed in yet another embodiment of the present application.

[0009] Description of reference numerals: 100-backlight module; 200-Linear polarizing element; 300-circular polarizing element, 310-first phase difference layer, 320-linear polarizing layer; 400-phase difference film, 410-substrate layer, 420-second phase difference layer; 510-first transmission roller, 520-second transmission roller; 600-users. DETAILED DESCRIPTION

[0010] The following will be combined with the drawings in the embodiments of the present application to clearly describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments in the present application belong to the scope of protection of this application.

[0011] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0012] The detection device and production line for phase difference film provided in the embodiments of the present application are described in detail below with reference to the accompanying drawings through specific embodiments and their application scenarios.

[0013] Please refer to Figures 1 to 6 As shown, in an embodiment of the present application, a detection device for a phase difference film 400 is provided, which includes: a backlight module 100, a linear polarizing element 200, and a circular polarizing element 300 arranged in sequence along a first direction, the first direction is used to intersect with the moving direction of the phase difference film 400, and optionally, the first direction is used to be perpendicular to the moving direction of the phase difference film 400, and the moving direction of the phase difference film 400 is, for example, Figure 1 The arrow A indicates the direction. The linear polarization element 200 and the circular polarization element 300 are arranged on opposite sides of the phase difference film 400. The phase difference film 400 is, for example, an optical compensation film, more specifically, a λ / 4 liquid crystal compensation film.

[0014] The circular polarizing element 300 includes a first phase difference layer 310 disposed toward the phase difference film 400 and a linear polarizing layer 320 disposed away from the phase difference film 400. The backlight module 100 is used to emit light to the linear polarizing element 200, and the light emitted by the backlight module 100 passes through the backlight module 100, the linear polarizing element 200, the phase difference film 400, the first phase difference layer 310 and the linear polarizing layer 320 in sequence along a first direction, for example.

[0015] Among them, the first phase difference layer 310 and the phase difference film 400 are used to make the light produce opposite rotation directions, and the optical axis direction of the first phase difference layer 310 is perpendicular to the optical axis direction of the phase difference film 400, so that the light emitted from the phase difference film 400 is converted into a first linear polarized light through the first phase difference layer 310, and the polarization direction of the first linear polarized light is set at an angle to the polarization direction of the linear polarizing layer 320, so that when there are defects in the phase difference film 400, the defective area and the qualified area of ​​the phase difference film 400 have different brightness.

[0016] During the actual detection process, the user 600 is located on the side of the linear polarizing layer 320 away from the first phase difference layer 310. When the user 600 observes the phase difference film 400 through the circular polarizing element 300, if the phase difference film 400 has defects, the defective area and the qualified area of ​​the phase difference film 400 will have different brightness. Therefore, it can be judged whether the phase difference film 400 has defects based on the brightness of each area of ​​the phase difference film 400.

[0017] In the embodiment of the present application, the first phase difference layer 310 of the circular polarizing element 300 can convert the light emitted by the phase difference film 400 into a first linear polarized light, and the polarization direction of the first linear polarized light is set at an angle to the polarization direction of the linear polarizing layer 320, so that when there are defects in the phase difference film 400, the defective area and the qualified area of ​​the phase difference film 400 have different brightness, so that the phase difference film 400 can be detected, and in the embodiment of the present application, the backlight module 100, the linear polarizing element 200 and the circular polarizing element 300 of the detection device are arranged along a first direction, and the first direction is used to intersect with the moving direction of the phase difference film 400. That is to say, the detection device provided in the embodiment of the present application does not need to change the position of the phase difference film 400, and the phase difference film 400 can be detected in situ while processing the phase difference film 400, thereby simplifying the detection operation of the phase difference film 400 and saving manpower.

[0018] Furthermore, currently when manufacturers mass-produce the phase difference film 400, they need to inspect the phase difference film 400 after the phase difference film 400 is completely rolled up. In this way, defects of the phase difference film 400 cannot be detected in time. The detection device provided in the embodiment of the present application can inspect the phase difference film 400 while the phase difference film 400 is moving, for example, before the phase difference film 400 is rolled up. Therefore, the detection device provided in the embodiment of the present application can detect defects of the phase difference film 400 in time, which is beneficial to improving the quality of the phase difference film 400.

[0019] In addition, the inventors have found that the circular polarizer 300 mentioned above can also be replaced by independently arranged linear polarizers and phase difference films, wherein the linear polarizer is equivalent to the linear polarization layer of the circular polarizer 300, and the phase difference film is equivalent to the phase difference layer of the circular polarizer 300. However, in this case, when detecting different positions of the phase difference film 400, the linear polarizer and the phase difference film need to be moved synchronously, which makes it difficult to move the linear polarizer and the phase difference film. However, the linear polarizer layer 320 and the first phase difference layer 310 of the circular polarizer 300 in the scheme adopted in this embodiment are an integrated structure, and the synchronous movement of the linear polarizer layer 320 and the first phase difference layer 310 can be achieved by moving the circular polarizer 300. Compared with independently arranged linear polarizers and phase difference films, the scheme adopted in this embodiment is less difficult to operate.

[0020] In another embodiment, reference Figure 3 As shown, the polarization direction of the first linear polarized light is the same as the polarization direction of the linear polarizing element 200. In this case, the first phase difference layer 310 completely offsets the influence of the phase difference film 400 on the light, and the polarization direction of the linear polarizing layer 320 is perpendicular to the polarization direction of the linear polarizing element 200, so that when there is a defect in the phase difference film 400, the defective area is bright and the qualified area is dark. In this way, the contrast between the bright state and the dark state is high, so it is relatively convenient and fast to determine whether the phase difference film 400 has a defect and the location of the defective area.

[0021] In addition, in the present embodiment, the polarization direction of the first linear polarized light is the same as the polarization direction of the linear polarizing element 200. In this way, the polarization direction of the linear polarizing layer 320 is made perpendicular to the polarization direction of the linear polarizing element 200, so that the defective area and the qualified area of ​​the phase difference film 400 can have different brightness, and the angle between the polarization direction of the linear polarizing layer 320 and the polarization direction of the linear polarizing element 200 can be adjusted more conveniently, thereby reducing the difficulty of using the detection device.

[0022] In the actual detection process, the light emitted from the first linear polarization element 200 is, for example, the third polarized light, and the polarization direction of the third polarized light is, for example, Figure 3 The direction indicated by the arrow line B in the middle, the polarization direction of the first linear polarized light is, for example, Figure 3 The direction indicated by the arrow line C in the middle, the polarization direction of the linear polarizing layer 320 is, for example, Figure 3 The direction indicated by the arrow line D.

[0023] In other optional embodiments, the polarization direction of the first linear polarized light is different from the polarization direction of the linear polarizing element 200. In this case, for example, the polarization direction of the linear polarizing layer 320 is perpendicular to the polarization direction of the first linear polarized light, so that when there are defects in the phase difference film 400, the defective area is bright and the qualified area is dark.

[0024] In another embodiment, reference Figure 4As shown, the polarization direction of the first linear polarized light is the same as the polarization direction of the linear polarizing element 200. Similarly, in this case, the first phase difference layer 310 completely offsets the influence of the phase difference film 400 on the light, and the angle between the polarization direction of the linear polarizing layer 320 and the polarization direction of the linear polarizing element 200 is 0 degrees or an acute angle, so that when there is a defect in the phase difference film 400, the defective area and the qualified area are both bright, and the brightness of the two is different. In this way, the angle between the polarization direction of the linear polarizing element 200 and the linear polarizing layer 320 is 0 degrees or an acute angle, so that the defective area and the qualified area of ​​the phase difference film 400 can be distinguished. As mentioned above, the angle between the linear polarizing layer 320 and the linear polarizing element 200 is convenient to adjust, thereby reducing the difficulty of using the detection device.

[0025] Optionally, the angle between the polarization direction of the linear polarizing layer 320 and the polarization direction of the linear polarizing element 200 is, for example, 35° to 55°, specifically, for example, 35 degrees, 45 degrees or 55 degrees.

[0026] It should be noted that Figure 4 The direction indicated by the arrow line F is the polarization direction of the linear polarization element 200, the direction indicated by the arrow line G is the polarization direction of the linear polarization layer 320, and Figure 4 The angle between the polarization direction of the linear polarizing layer 320 and the polarization direction of the linear polarizing element 200 is approximately 45 degrees.

[0027] In other optional embodiments, the polarization direction of the first linear polarized light is different from the polarization direction of the linear polarizing element 200. In this case, for example, the angle between the polarization direction of the linear polarizing layer 320 and the polarization direction of the first linear polarized light is set to 0 degrees or an acute angle, so that when there are defects in the phase difference film 400, both the defective area and the qualified area are bright and have different brightness.

[0028] In another embodiment, reference Figure 3 and Figure 4 As shown, the angle between the polarization direction of the linear polarizing element 200 and the optical axis direction of the phase difference film 400 is, for example, 45 degrees, so that the light emitted by the linear polarizing element 200 is converted into circularly polarized light through the phase difference film 400. The uniformity of the circularly polarized light is good, so that when there are defects in the phase difference film 400, it is beneficial to improve the contrast between the defective area and the qualified area of ​​the phase difference film 400, thereby improving the detection accuracy of the phase difference film 400.

[0029] It should be noted that the handedness of the circularly polarized light emitted from the phase difference film 400 is, for example, Figure 3 The direction indicated by arrow line E, or Figure 4 The direction indicated by the arrow line H.

[0030] In other optional embodiments, the angle between the polarization direction of the linear polarizing element 200 and the optical axis direction of the phase difference film 400 may also be greater than zero degrees and less than 45 degrees, or greater than 45 degrees and less than 90 degrees. In this case, the phase difference film 400 converts the light emitted by the linear polarizing element 200 into elliptically polarized light.

[0031] In another embodiment, reference Figure 5 and Figure 6 As shown, the linear polarizing element 200 is arranged toward the substrate layer 410 of the phase difference film 400, so that the light emitted by the linear polarizing element 200 passes through the substrate layer 410 and enters the phase difference film 400, and the polarization direction of the linear polarizing element 200 is the same as the optical axis direction of the substrate layer 410, so that when the substrate layer 410 has an in-plane phase difference, the light emitted by the substrate layer 410 is a second linear polarized light, and the polarization direction of the second linear polarized light is the same as the polarization direction of the linear polarizing element 200, that is, the polarized light emitted by the linear polarizing element 200 can pass through the substrate layer 410 without changing the polarization direction. In this way, even if the substrate layer 410 has an in-plane phase difference, the defective area and the qualified area of ​​the phase difference film 400 can still have different brightness. In other words, when the substrate layer 410 has an in-plane phase difference, the detection device provided in this embodiment can still detect the phase difference film 400. In this way, the detection device provided in this embodiment can detect various types of phase difference films 400, so that the detection device has better applicability.

[0032] In addition, the solution adopted in this embodiment does not require additional structures. The phase difference film 400 can be detected by simply adjusting the polarization direction of the linear polarizer 200 and the optical axis direction of the substrate layer 410 to be the same, thereby simplifying the structure of the detection device.

[0033] Optionally, refer to Figure 6 As shown, the phase difference film 400 further includes a second phase difference layer 420, which is located on the side of the substrate layer 410 facing the circular polarization element 300. When there is no in-plane phase difference in the substrate layer 410, the second phase difference layer 420 and the first phase difference layer 310 mentioned above are used, for example, to make the light produce opposite hand directions, and the optical axis direction of the second phase difference layer 420 is, for example, perpendicular to the optical axis direction of the first phase difference layer 310, so that the light emitted from the second phase difference layer 420 is converted into the first linear polarized light mentioned above through the first phase difference layer 310. In addition, the substrate layer 410 is, for example, a polyethylene terephthalate layer.

[0034] As a specific implementation method, refer to Figure 6As shown, the angle between the polarization direction of the linear polarizing element 200 and the optical axis of the phase difference film 400 is, for example, an acute angle, and the angle between the two is not equal to 45 degrees. In this case, the light emitted from the phase difference film 400 is, for example, elliptically polarized light. Figure 6 The direction indicated by the arrow line I is the hand direction of the elliptically polarized light, and the elliptically polarized light is converted into the first linearly polarized light mentioned above after passing through the first phase difference layer 310. Figure 6 In the figure, the direction indicated by the arrow line J is the polarization direction of the first linear polarizing element 200, the direction indicated by the arrow line K is the optical axis direction of the substrate layer 410, the direction indicated by the arrow line L is the polarization direction of the linear polarizing layer 320, and Figure 6 The angle between the polarization direction of the linear polarizing layer 320 and the polarization direction of the linear polarizing element 200 is, for example, greater than or equal to 35 degrees and less than or equal to 55 degrees, specifically, for example, 35 degrees or 45 degrees.

[0035] In other optional embodiments, the polarization direction of the linear polarizing element 200 may be different from the optical axis direction of the substrate layer 410 . In this case, for example, other optical elements are additionally provided to convert the light emitted from the substrate layer 410 into a second linear polarized light, thereby realizing the detection of the phase difference film 400 .

[0036] In another embodiment, in the second direction, the size of the backlight module 100 is not less than the size of the phase difference film 400, so that light can pass through the phase difference film 400 in the second direction, and the second direction, the first direction and the moving direction of the phase difference film 400 intersect each other, for example, they are perpendicular to each other. Optionally, the moving direction of the phase difference film 400 is, for example, the length direction of the phase difference film 400, the first direction is, for example, the thickness direction of the phase difference film 400, and the second direction is, for example, the width direction of the phase difference film 400.

[0037] In this embodiment, light passes through the phase difference film 400 in the second direction. In this way, by moving the linear polarization element 200 and the circular polarization element 300 along the second direction, any position of the phase difference film 400 in the second direction can be detected, thereby reducing the missed detection rate of the phase difference film 400 and improving the detection accuracy of the phase difference film 400.

[0038] In other optional embodiments, the size of the backlight module 100 may also be smaller than the size of the phase difference film 400. In this case, for example, light passes through a portion of the phase difference film 400 in the second direction. This means that moving the linear polarizing element 200 and the circular polarizing element 300 along the second direction can only detect a portion of the phase difference film 400 in the second direction.

[0039] In another embodiment, the backlight module 100 is provided with scale lines along the second direction, and the second direction, the first direction, and the moving direction of the phase difference film 400 intersect each other. In this way, when there is a defect in the phase difference film 400, the position of the defective area in the second direction of the phase difference film 400 can be conveniently and quickly determined with the help of the scale lines, which is helpful for subsequent processing of the defective area and for discovering periodic defects, thereby helping to find the cause of the defect.

[0040] In other optional embodiments, the backlight module 100 may not be provided with scale lines along the second direction.

[0041] In another embodiment, the detection device further includes a meter, which is used to contact the phase difference film 400 and detect the moving length of the phase difference film 400. In this way, when there is a defect in the phase difference film 400, the moving length of the phase difference film 400 corresponding to the defective area can be determined more conveniently and quickly with the help of the meter, which is also helpful for subsequent processing of the defective area and for discovering periodic defects, thereby helping to find the cause of the defect.

[0042] As a specific implementation, the meter counter includes, for example, a meter wheel, and the meter wheel is driven to rotate while the phase difference film 400 moves, thereby realizing the detection of the moving length of the phase difference film 400 .

[0043] In other optional embodiments, the detection device may not include a meter.

[0044] In another embodiment, the linear polarizing layer 320 includes a first sub-protective layer, a polarizing sub-layer, and a second sub-protective layer which are sequentially stacked along the thickness direction of the linear polarizing layer 320, and the first phase difference layer 310 is disposed on one side of the thickness direction of the linear polarizing layer 320 and is attached to the first sub-protective layer. In this configuration, the polarizing sub-layer is located between the first sub-protective layer and the second sub-protective layer, and both the first sub-protective layer and the second sub-protective layer can protect the polarizing sub-layer, thereby extending the service life of the polarizing sub-layer.

[0045] Optionally, the first sub-protective layer is connected to the polarizing layer through a first adhesive layer, and the second sub-protective layer is connected to the polarizing layer through a second adhesive layer, and specifically, the first adhesive layer and the second adhesive layer are both glue layers. In this way, the first sub-protective layer and the second sub-protective layer are both connected to the polarizing layer by bonding, and the bonding method has a good connection strength, thereby preventing the polarizing layer from being separated from the first sub-protective layer and the second sub-protective layer.

[0046] As a specific implementation, the first sub-protective layer is, for example, a triacetyl cellulose layer or a phase difference layer, the polarizing layer is, for example, a polyvinyl alcohol layer, and the second sub-protective layer is, for example, a triacetyl cellulose layer. The first adhesive layer is, for example, a polyvinyl alcohol adhesive layer or a photosensitive adhesive layer, and the second adhesive layer is, for example, a polyvinyl alcohol adhesive layer or a photosensitive adhesive layer.

[0047] In other optional embodiments, the linear polarizing layer 320 may also include only the polarizing sub-layer, but not the first sub-protective layer and the second sub-protective layer. In this case, the polarizing sub-layer is, for example, directly bonded to the linear polarizing layer 320 .

[0048] As a specific implementation, the backlight module 100 includes, for example, a backlight panel and a light source disposed on the backlight panel. When the light source is turned on, the backlight panel lights up to emit light to the linear polarization element 200 , and the light source is, for example, a halogen lamp or a light emitting diode.

[0049] refer to Figure 1 As shown, a production line is also provided in an embodiment of the present application, which includes a driving mechanism and the detection device mentioned above, and the driving mechanism is used to drive the phase difference film 400 to move.

[0050] Optionally, the driving mechanism includes, for example, a first transmission roller 510 and a second transmission roller 520, and the first transmission roller 510 and the circular polarizing element 300 are, for example, disposed on the same side of the phase difference film 400, and the second transmission roller 520 and the linear polarizing element 200 are, for example, disposed on the same side of the phase difference film 400, and the phase difference film 400 sequentially bypasses the first transmission roller 510 and the second transmission roller 520, and the first transmission roller 510 and the second transmission roller 520 are both used to drive the phase difference film 400 to move. The first transmission roller 510 and the second transmission roller 520 have a relatively simple structure, which is conducive to reducing the cost of the production line and simplifying the structure of the production line.

[0051] As a specific implementation, the production line also includes a curing device, which is used to cure the liquid coated on the substrate layer 410 to obtain the corresponding phase difference film 400. In other words, after the curing treatment, the phase difference film 400 is detected by the detection device provided in this embodiment.

[0052] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

Claims

1. A detection device for a phase difference film (400), characterized in that: include: A backlight module (100), a linear polarizing element (200), and a circular polarizing element (300) are sequentially arranged along a first direction, the first direction being used to intersect with the moving direction of the phase difference film (400), and the linear polarizing element (200) and the circular polarizing element (300) are used to be arranged on two opposite sides of the phase difference film (400), and the circular polarizing element (300) comprises a first phase difference layer (310) arranged toward the phase difference film (400) and a linear polarizing layer (320) arranged away from the phase difference film (400); The first phase difference layer (310) and the phase difference film (400) are used to make the light produce opposite rotation directions, and the optical axis direction of the first phase difference layer (310) is perpendicular to the optical axis direction of the phase difference film (400), so that the light emitted by the phase difference film (400) is converted into first linear polarized light through the first phase difference layer (310), and the polarization direction of the first linear polarized light is arranged at an angle with the polarization direction of the linear polarization layer (320), so that when the phase difference film (400) has defects, the defective area and the qualified area of ​​the phase difference film (400) have different brightness.

2. The detection device according to claim 1, characterized in that: The polarization direction of the first linear polarized light is the same as the polarization direction of the linear polarization element (200), and the polarization direction of the linear polarization layer (320) is perpendicular to the polarization direction of the linear polarization element (200), so that when there is a defect in the phase difference film (400), the defective area is in a bright state and the qualified area is in a dark state.

3. The detection device according to claim 1, characterized in that: The polarization direction of the first linear polarized light is the same as the polarization direction of the linear polarization element (200); The angle between the polarization direction of the linear polarization layer (320) and the polarization direction of the linear polarization element (200) is 0 degrees or an acute angle, so that when there is a defect in the phase difference film (400), both the defective area and the qualified area are bright and have different brightness.

4. The detection device according to claim 1, characterized in that: The angle between the polarization direction of the linear polarization element (200) and the optical axis direction of the phase difference film (400) is 45 degrees, so that the light emitted by the linear polarization element (200) is converted into circularly polarized light through the phase difference film (400).

5. The detection device according to claim 1, characterized in that: The linear polarization element (200) is used to be arranged toward the substrate layer (410) of the phase difference film (400), so that the light emitted by the linear polarization element (200) passes through the substrate layer (410) and enters the phase difference film (400), and the polarization direction of the linear polarization element (200) is used to be the same as the optical axis direction of the substrate layer (410), so that when the substrate layer (410) has an in-plane phase difference, the light emitted by the substrate layer (410) is a second linear polarized light, and the polarization direction of the second linear polarized light is the same as the polarization direction of the linear polarization element (200).

6. The detection device according to claim 1, characterized in that: In the second direction, the size of the backlight module (100) is not less than the size of the phase difference film (400), so that light can pass through the phase difference film (400) in the second direction, and the second direction, the first direction and the moving direction of the phase difference film (400) intersect each other.

7. The detection device according to claim 1, characterized in that: The backlight module (100) is provided with scale lines along a second direction, and the second direction, the first direction, and the moving direction of the phase difference film (400) intersect each other.

8. The detection device according to claim 1, characterized in that: The detection device further comprises a meter, wherein the meter is used to contact the phase difference film (400) and detect the moving length of the phase difference film (400).

9. The detection device according to claim 1, characterized in that: The linear polarizing layer (320) comprises a first sub-protective layer, a polarizing sub-layer and a second sub-protective layer which are sequentially stacked in a thickness direction of the linear polarizing layer (320); the first phase difference layer (310) is arranged on one side in the thickness direction of the linear polarizing layer (320) and is bonded to the first sub-protective layer.

10. A production line, characterized in that: It comprises a driving mechanism and a detection device as claimed in any one of claims 1 to 9, wherein the driving mechanism is used to drive the phase difference film (400) to move.

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